JP7768435B2 - Optical system and imaging device - Google Patents

Description

This disclosure relates to an optical system suitable for an interchangeable lens that can be attached to, for example, a digital still camera or a digital mirrorless camera, and an imaging device equipped with such an optical system.

In recent years, the number of pixels in the image sensors used in interchangeable lens digital camera systems has been increasing, and optical systems are being required to provide correspondingly high image quality. Furthermore, compact and lightweight camera bodies are the norm for the interchangeable lens mirrorless cameras that have become increasingly popular in recent years, and optical systems that are also being required to be compact and lightweight are being developed (see Patent Document 1).

Japanese Patent Application Laid-Open No. 2017-215492

On the other hand, telephoto lenses compatible with large image sensors such as full-frame sensors are generally large in size, so the optical system must have a weight balance with a center of gravity close to that of the camera body, making it ideal for small, lightweight camera bodies in terms of maneuverability.

It is desirable to provide an optical system that is lightweight, easy to handle, and has high optical performance across the entire screen, as well as an imaging device equipped with such an optical system.

An optical system according to an embodiment of the present disclosure includes, in order from the object side to the image surface side, a first lens group having positive refractive power as a whole and being fixed relative to the image surface during focusing; a second lens group having positive refractive power as a whole and performing focusing from infinity to a close distance by moving the whole group in the direction of the optical axis; and a third lens group divided, in order from the object side to the image surface side, into groups 3a, 3b, and 3c, wherein group 3b corrects image blur by moving in a direction approximately perpendicular to the optical axis, having negative refractive power as a whole and being fixed relative to the image surface during focusing. An aperture stop is located within the third lens group between groups 3a and 3b, and the third lens group satisfies conditional expressions (1) to (3), and the third lens group includes at least one negative lens that satisfies conditional expression (6):
D_g1max/f>0.23...(2)
D_3bImg/f<0.24...(3)
θgF_3cn-(-0.001801*νd_3cn+0.648262)>0.008...(6)
however,
L: distance from the surface of the first lens group closest to the object to the image plane f: focal length of the entire system when focused at infinity D_g1max: maximum air gap on the optical axis within the first lens group D_3bImg: distance from the surface of the 3b group closest to the object to the image plane θgF_3cn: partial dispersion ratio between the g line and the F line of the negative lens in the 3c group νd_3cn: Abbe number for the d line of the negative lens in the 3c group
Moreover, an optical system according to an embodiment of the present disclosure may comprise, in order from the object side to the image surface side, a first lens group having positive refractive power as a whole and being fixed relative to the image surface during focusing; a second lens group having negative refractive power as a whole and performing focusing from infinity to a close distance by moving the whole group in the direction of the optical axis; and a third lens group divided, in order from the object side to the image surface side, into groups 3a, 3b, and 3c, wherein group 3b performs image blur correction by moving in a direction approximately perpendicular to the optical axis, having positive refractive power as a whole and being fixed relative to the image surface during focusing; an aperture stop between groups 3a and 3b in the third lens group ; and the third lens group may include at least one negative lens that satisfies conditional expressions (1) to (3).

An imaging device according to one embodiment of the present disclosure includes an optical system and an imaging element that outputs an imaging signal corresponding to an optical image formed by the optical system, and the optical system is configured using the optical system according to the embodiment of the present disclosure.

An optical system or imaging device according to one embodiment of the present disclosure is composed of three lens groups overall, with the configuration of each lens group optimized.

1 is a lens cross-sectional view illustrating a first configuration example (Example 1) of an optical system according to an embodiment of the present disclosure. 2 is an aberration diagram showing longitudinal aberration when focusing at infinity in the optical system according to Example 1 in which specific values are applied to the optical system shown in FIG. 1 . 2 is an aberration diagram showing lateral aberration when focused on infinity and when image stabilization is not performed in the optical system according to Example 1 in which specific values are applied to the optical system shown in FIG. 1 . 2 is an aberration diagram showing lateral aberration when focusing on infinity and when vibration reduction is performed in the optical system according to Example 1 in which specific values are applied to the optical system shown in FIG. 1 . FIG. 10 is a lens cross-sectional view showing a second configuration example (Example 2) of the optical system according to the embodiment. 6 is an aberration diagram showing longitudinal aberration when focusing at infinity in an optical system according to Example 2 in which specific numerical values are applied to the optical system shown in FIG. 5 . 6 is an aberration diagram showing lateral aberration when focused on infinity and when image stabilization is not performed in an optical system according to Example 2 in which specific values are applied to the optical system shown in FIG. 5 . 6 is an aberration diagram showing lateral aberration when focusing on infinity and when vibration reduction is performed in an optical system according to Example 2 in which specific values are applied to the optical system shown in FIG. 5 . FIG. 10 is a lens cross-sectional view showing a third configuration example (Example 3) of the optical system according to the embodiment. 10 is an aberration diagram showing longitudinal aberration when focusing at infinity in an optical system according to Example 3 in which specific values are applied to the optical system shown in FIG. 9 . 10 is an aberration diagram showing lateral aberration when focused on infinity and when image stabilization is not performed in the optical system according to Example 3 in which specific values are applied to the optical system shown in FIG. 9 . 10A and 10B are aberration diagrams showing lateral aberrations when focusing on infinity and when vibration reduction is performed in an optical system according to Example 3 in which specific values are applied to the optical system shown in FIG. 9 . FIG. 10 is a lens cross-sectional view showing a fourth configuration example (Example 4) of an optical system according to an embodiment. 14 is an aberration diagram showing longitudinal aberration when focusing at infinity in the optical system according to Example 4 in which specific values are applied to the optical system shown in FIG. 13. 14A and 14B are aberration diagrams showing lateral aberrations when focused on infinity and when image stabilization is not performed in the optical system according to Example 4 in which specific values are applied to the optical system shown in FIG. 13. 14A and 14B are aberration diagrams showing lateral aberrations when focusing on infinity and when vibration reduction is performed in an optical system according to Example 4 in which specific values are applied to the optical system shown in FIG. 13. FIG. 10 is a lens cross-sectional view showing a fifth configuration example (Example 5) of an optical system according to an embodiment. 18 is an aberration diagram showing longitudinal aberration when focusing at infinity in the optical system according to Example 5 in which specific values are applied to the optical system shown in FIG. 17. 18A and 18B are aberration diagrams showing lateral aberrations when focused on infinity and when image stabilization is not performed in the optical system according to Example 5 in which specific values are applied to the optical system shown in FIG. 17. 18A and 18B are aberration diagrams showing lateral aberrations when focusing on infinity and when vibration reduction is performed in an optical system according to Example 5 in which specific values are applied to the optical system shown in FIG. 17. FIG. 10 is a lens cross-sectional view showing a sixth configuration example (Example 6) of an optical system according to an embodiment. 22 is an aberration diagram showing longitudinal aberration when focusing at infinity in an optical system according to Example 6 in which specific values are applied to the optical system shown in FIG. 21. 22 is an aberration diagram showing lateral aberration when focused on infinity and when image stabilization is not performed in the optical system according to Example 6 in which specific values are applied to the optical system shown in FIG. 21. FIG. 22A and 22B are aberration diagrams showing lateral aberrations when focusing on infinity and when vibration reduction is performed in an optical system according to Example 6 in which specific values are applied to the optical system shown in FIG. 21 . FIG. 10 is a lens cross-sectional view showing a seventh configuration example (Example 7) of an optical system according to an embodiment. 26 is an aberration diagram showing longitudinal aberration when focusing at infinity in the optical system according to Example 7 in which specific values are applied to the optical system shown in FIG. 25. 26 is an aberration diagram showing lateral aberration when focused on infinity and when image stabilization is not performed in the optical system according to Example 7 in which specific values are applied to the optical system shown in FIG. 25. FIG. 26 is an aberration diagram showing lateral aberration when focusing on infinity and when vibration reduction is performed in the optical system according to Example 7 in which specific values are applied to the optical system shown in FIG. 25. FIG. FIG. 13 is a lens cross-sectional view showing an eighth configuration example (Example 8) of an optical system according to an embodiment. FIG. 30 is an aberration diagram showing longitudinal aberration when focusing at infinity in the optical system according to Example 8 in which specific values are applied to the optical system shown in FIG. 29 . 30 is an aberration diagram showing lateral aberration when focused on infinity and when image stabilization is not performed in the optical system according to Example 8 in which specific values are applied to the optical system shown in FIG. 29. 30 is an aberration diagram showing lateral aberration when focusing on infinity and when image stabilization is performed in the optical system according to Example 8 in which specific values are applied to the optical system shown in FIG. 29. FIG. 13 is a lens cross-sectional view showing a ninth configuration example (Example 9) of an optical system according to an embodiment. 34 is an aberration diagram showing longitudinal aberration when focusing at infinity in the optical system according to Example 9 in which specific values are applied to the optical system shown in FIG. 33. 34 is an aberration diagram showing lateral aberration when focused on infinity and when image stabilization is not performed in the optical system according to Example 9 in which specific values are applied to the optical system shown in FIG. 33. FIG. 34 is an aberration diagram showing lateral aberration when focusing on infinity and when image stabilization is performed in the optical system according to Example 9 in which specific values are applied to the optical system shown in FIG. 33. FIG. FIG. 16 is a lens cross-sectional view showing a tenth configuration example (Example 10) of an optical system according to an embodiment. FIG. 38 is an aberration diagram showing longitudinal aberration when focusing at infinity in the optical system according to Example 10 in which specific values are applied to the optical system shown in FIG. 37. FIG. 38 is an aberration diagram showing lateral aberration in an optical system according to Example 10 in which specific values are applied to the optical system shown in FIG. 37 when focused on infinity and when image stabilization is not performed. 38 is an aberration diagram showing lateral aberration when focusing on infinity and when image stabilization is performed in the optical system according to Example 10 in which specific values are applied to the optical system shown in FIG. 37. FIG. FIG. 12 is a lens cross-sectional view showing an eleventh configuration example (Example 11) of an optical system according to an embodiment. 42 is an aberration diagram showing longitudinal aberration when focusing at infinity in the optical system according to Example 11 in which specific numerical values are applied to the optical system shown in FIG. 41. 42 is an aberration diagram showing lateral aberration when focused on infinity and when image stabilization is not performed in the optical system according to Example 11 in which specific values are applied to the optical system shown in FIG. 41. FIG. 42 is an aberration diagram showing lateral aberration when focusing on infinity and when image stabilization is performed in the optical system according to Example 11 in which specific values are applied to the optical system shown in FIG. 41. FIG. FIG. 1 is a block diagram illustrating an example of the configuration of an imaging device. 1 is a block diagram showing an example of a schematic configuration of a vehicle control system; FIG. 2 is an explanatory diagram showing an example of the installation positions of an outside-vehicle information detection unit and an imaging unit. 1 is a configuration diagram showing an example of a schematic configuration of an endoscopic surgery system. FIG. 49 is a block diagram showing an example of the functional configuration of the camera head and CCU shown in FIG. 48.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be made in the following order.
0. Comparative Example 1. Basic Lens Configuration 2. Actions and Effects 3. Application Examples to Imaging Devices 4. Numerical Examples of Lenses 5. Application Examples 6. Other Embodiments

<0. Comparative Example>
Compact and lightweight camera bodies are the norm for interchangeable lens mirrorless cameras, which have become popular in recent years. However, telephoto lenses compatible with large image sensors such as full-frame sensors generally end up being quite large, so there is a strong demand for optical systems that have a weight balance with a center of gravity close to the camera body, which is ideal for compact and lightweight bodies, and for the optical system itself to be lightweight.

Patent Document 1 (JP 2017-215492 A) proposes an optical system that is composed of, in order from the object side to the image plane side, a first lens group with positive refractive power, a second lens group with positive or negative refractive power, and a third lens group with positive or negative refractive power, and in which the second lens group moves during focusing, changing the spacing between adjacent lens groups. In the optical system in Patent Document 1, the first lens group includes a positive lens G1p arranged closest to the object, a positive lens G2p arranged closer to the image plane than the positive lens G1p, and a positive lens G3p arranged closer to the image plane than the positive lens G2p. In the optical system of Patent Document 1, when the focal length of the optical system is f, the distance on the optical axis from the lens surface of the first lens group closest to the object to the image plane is LD, the distance on the optical axis between the positive lens G1p and the lens arranged adjacent to the positive lens G1p on the image plane side is D12, the Abbe number of the material of the positive lens G2p is νdG2p, and the Abbe number of the material of the positive lens G3p is νdG3p, the following conditional expression is satisfied.
LD/f<1.0
0.20≦D12/LD<0.500
νdG2p>73.0
νdG3p>73.0

The optical system in Patent Document 1 achieves a lightweight lens barrel by providing a large air gap within the first lens group. However, while Patent Document 1 states that any lens block within the optical system can be configured as the vibration isolation group, in reality, only a very limited number of lens blocks can function as the vibration isolation group with the appropriate vibration isolation sensitivity (the ratio of the amount of image movement to the amount of movement of the vibration isolation group in a direction perpendicular to the optical axis) and good optical performance when the vibration isolation group shifts, making it impossible to configure any lens block as the vibration isolation group to achieve the minimum level of vibration isolation functionality for the optical system. Furthermore, in Patent Document 1, the lens blocks that could actually fulfill the role of the vibration isolation group in the examples are all located away from the image plane, which means the center of gravity of the lens barrel is located away from the camera body, making it difficult to achieve comfortable maneuverability of the lens barrel.

Therefore, it is desirable to provide an optical system that is optimal for mirrorless camera systems, etc., that is a telephoto lens with vibration reduction functionality compatible with large image sensors, is lightweight, has a center of gravity close to the image plane, is easy to maneuver, and has high optical performance with chromatic aberrations and other aberrations suppressed across the entire image plane.
An optical system according to an embodiment of the present disclosure described below is suitable for a telephoto lens used in such a mirrorless digital camera or the like.

<1. Basic lens structure>
FIG. 1 illustrates a first configuration example of an optical system according to an embodiment of the present disclosure, which corresponds to the configuration of Example 1 described below. FIG. 5 illustrates a second configuration example of an optical system according to an embodiment, which corresponds to the configuration of Example 2 described below. FIG. 9 illustrates a third configuration example of an optical system according to an embodiment, which corresponds to the configuration of Example 3 described below. FIG. 13 illustrates a fourth configuration example of an optical system according to an embodiment, which corresponds to the configuration of Example 4 described below. FIG. 17 illustrates a fifth configuration example of an optical system according to an embodiment, which corresponds to the configuration of Example 5 described below. FIG. 21 illustrates a sixth configuration example of an optical system according to an embodiment, which corresponds to the configuration of Example 6 described below. FIG. 25 illustrates a seventh configuration example of an optical system according to an embodiment, which corresponds to the configuration of Example 7 described below. FIG. 29 illustrates an eighth configuration example of an optical system according to an embodiment, which corresponds to the configuration of Example 8 described below. FIG. 33 illustrates a ninth configuration example of an optical system according to an embodiment, which corresponds to the configuration of Example 9 described below. FIG. 37 illustrates a tenth configuration example of an optical system according to an embodiment, which corresponds to the configuration of Example 10 described below. FIG. 41 illustrates an eleventh configuration example of an optical system according to an embodiment, which corresponds to the configuration of Example 11 described below.

In Figure 1 and other figures, Z1 indicates the optical axis. An optical component such as a cover glass for protecting the image sensor may be disposed between the optical systems 1 to 11 according to the first to sixth configuration examples and the image plane Simg. In addition to the cover glass, various optical filters such as a low-pass filter or an infrared cut filter may also be disposed.

The configuration of an optical system according to one embodiment of the present disclosure will be described below, appropriately corresponding to optical systems 1 to 11 according to the configuration examples shown in Figure 1 and elsewhere, but the technology according to the present disclosure is not limited to the configuration examples shown.

The optical system according to one embodiment is composed of, in order from the object side to the image plane side, a first lens group GR1, a second lens group GR2, and a third lens group GR3.

The first lens group GR1 as a whole has positive refractive power, and the entire group is fixed relative to the image plane Simg during focusing.

The second lens group GR2 has positive or negative refractive power as a whole, and focuses from infinity to close distances by moving the entire group along the optical axis. Note that each configuration example, such as Figure 1, shows the lens arrangement when focusing at infinity. In the first configuration example (Example 1) to the sixth configuration example (Example 6), the second lens group GR2 has positive refractive power as a whole, and moves toward the object when focusing from infinity to close distances. In the seventh configuration example (Example 7) to the eleventh configuration example (Example 11), the second lens group GR2 has negative refractive power as a whole, and moves toward the image plane when focusing from infinity to close distances.

The third lens group GR3 has negative or positive refractive power as a whole, and is fixed relative to the image plane Simg during focusing. The third lens group GR3 is divided into the 3a group GR3a, the 3b group GR3b, and the 3c group GR3c, from the object side to the image plane side. The 3b group GR3b is an image stabilization group that corrects image blur by moving in a direction approximately perpendicular to the optical axis Z1. In the first configuration example (Example 1) to the tenth configuration example (Example 10), the third lens group GR3 has negative refractive power as a whole. In the eleventh configuration example (Example 11), the third lens group GR3 has positive refractive power as a whole.

It is desirable that the aperture stop St be positioned between the 3a group GR3a and the 3b group GR3b.

Moreover, the optical system according to one embodiment satisfies the following conditional expressions (1) to (3).
L/f<1...(1)
D_g1max/f>0.23...(2)
D_3bImg/f<0.24...(3)
however,
L: distance from the surface of the first lens group GR1 closest to the object to the image plane Simg; f: focal length of the entire system when focusing at infinity; D_g1max: maximum air gap on the optical axis within the first lens group GR1; D_3bImg: distance from the surface of the 3b group GR3b closest to the object to the image plane Simg.

In addition, it is desirable for the optical system according to one embodiment to satisfy certain conditional expressions, etc., which will be described later.

<2. Actions and Effects>
Next, the operation and effects of the optical system according to the embodiment of the present disclosure will be described, along with a more desirable configuration of the optical system according to the embodiment of the present disclosure.
The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

In one embodiment of the optical system, the overall configuration is composed of three lens groups, with each lens group optimized for its configuration. This makes it lightweight, with the center of gravity located close to the image plane, making it easy to maneuver, and achieving high optical performance with chromatic aberrations and other aberrations suppressed across the entire image plane.

In an optical system according to one embodiment, a large air gap is provided within the first lens group GR1, achieving a lightweight design. Furthermore, in an optical system according to one embodiment, by positioning the vibration isolation group (3b group GR3b) at the rear, the actuator that drives the lens can be positioned closer to the image plane, bringing the center of gravity closer to the image plane, resulting in an optical system with excellent maneuverability.

Satisfying conditional formula (1) above generally indicates that the optical system is a telephoto system. In optical systems that satisfy conditional formula (1), such as telephoto lenses, the third lens group GR3, which is fixed relative to the image plane Simg, is divided into three blocks: group 3a GR3a, group 3b GR3b, and group 3c GR3c. The central group 3b GR3b is used as a vibration reduction group, and is positioned relative to the image plane Simg to satisfy conditional formula (3). By sandwiching the vibration reduction group 3b GR3b between group 3a GR3a and group 3c GR3c, which complement each other in aberration correction during vibration reduction, and by positioning the vibration reduction group at a rear position relative to the image plane Simg to satisfy conditional formula (3), the height at which light rays pass through the vibration reduction group from on-axis to the peripheral image height, which is related to aberration degradation during vibration reduction, is reduced, resulting in good imaging performance even during vibration reduction. In addition, because the light ray passage height is reduced, the diameter of the vibration isolation group can be reduced, and it is also easy to make the actuator unit that drives the vibration isolation group smaller and lighter. Furthermore, by placing the vibration isolation group at the rear, the actuator that drives the vibration isolation group is also located at the rear, which moves the center of gravity closer to the image plane, resulting in an optical system with excellent maneuverability.

Furthermore, by satisfying conditional expressions (1) and (3) as well as conditional expression (2), it is possible to reduce the weight of the optical elements at the front of the lens barrel, which accounts for a large portion of the lens barrel weight in a telephoto lens. However, simply satisfying conditional expression (2) and providing a large air gap within the first lens group GR1 would cause chromatic aberrations occurring in the optical system closer to the object than the maximum air gap to be magnified in proportion to the distance as they propagate through the air gap, making it difficult to achieve high imaging performance as a whole. However, by simultaneously satisfying conditional expression (3) above, the 3c group GR3c, along with the 3b group GR3b, is positioned at the rear of the optical system, i.e., close to the image plane Simg and at a high marginal ray height, thereby providing high aberration correction capabilities. This allows them to cancel out aberrations occurring within the first lens group GR1, which is positioned roughly symmetrically in the optical system, and thus enables high imaging performance to be achieved even when a large air gap is provided within the first lens group GR1.

In order to better realize the effects of the above-described conditional expressions (2) and (3), it is more desirable to set the numerical ranges of the conditional expressions (2) and (3) as shown in the following conditional expressions (2)′ and (3)′.
D_g1max/f>0.24...(2)'
D_3bImg/f<0.23...(3)'

Even more preferably, the numerical ranges of the conditional expressions (2) and (3) should be set as shown in the following conditional expressions (2)'' and (3)''.
D_g1max/f>0.25...(2)''
D_3bImg/f<0.22...(3)''

In the optical system according to one embodiment, it is desirable that the first lens group GR1 has at least one positive lens that satisfies the following conditional expressions (4) and (5).
νd_1p>90...(4)
θgF_1p-(-0.001801*νd_1p+0.648262)>0.04...(5)
however,
νd_1p: Abbe number for the d-line of the positive lens in the first lens group GR1. θgF_1p: partial dispersion ratio for the g-line and F-line of the positive lens in the first lens group GR1.

By using a low-dispersion glass material with strong anomalous dispersion that simultaneously satisfies conditional expressions (4) and (5) for the positive lens in the first lens group GR1, chromatic aberration, a problem in telephoto lenses, can be effectively corrected. Below the lower limit of conditional expression (4), correction of first- and second-order chromatic aberration becomes insufficient, resulting in a deterioration in imaging performance across the entire frame. Below the lower limit of conditional expression (5), correction of second-order chromatic aberration becomes insufficient, resulting in a deterioration in imaging performance across the entire frame. Note that first-order chromatic aberration refers to chromatic aberration between the F-line and C-line, while second-order chromatic aberration refers to chromatic aberration in the even shorter wavelength region (typically the g-line).

In order to more effectively realize the effect of the above-mentioned conditional expression (5), it is more desirable to set the numerical range of the conditional expression (5) as shown in the following conditional expression (5)'.
θgF_1p-(-0.001801*νd_1p+0.648262)>0.05 ...(5)'

Even more preferably, the numerical range of conditional expression (5) should be set as shown in the following conditional expression (5)''.
θgF_1p-(-0.001801*νd_1p+0.648262)>0.06 ...(5)''

In the optical system according to one embodiment, it is desirable that the 3c group GR3c includes at least one negative lens that satisfies the following conditional expression (6).
θgF_3cn-(-0.001801*νd_3cn+0.648262)>0.008...(6)
however,
θgF_3cn: partial dispersion ratio between the g line and the F line of the negative lens in the 3c group GR3c. νd_3cn: Abbe number for the d line of the negative lens in the 3c group GR3c.

By using an anomalous dispersion glass material that satisfies conditional expression (6) for the negative lens in group 3c GR3c, lateral chromatic aberration is well corrected, resulting in good imaging performance even at the periphery. If the lower limit of conditional expression (6) is not met, correction of primarily secondary lateral chromatic aberration becomes insufficient, resulting in poor imaging performance at the periphery of the image.

In order to more effectively realize the effect of the above-mentioned conditional expression (6), it is more desirable to set the numerical range of the conditional expression (6) as shown in the following conditional expression (6)'.
θgF_3cn-(-0.001801*νd_3cn+0.648262)>0.012 ...(6)'

Even more preferably, the numerical range of conditional expression (6) should be set as in the following conditional expression (6)''.
θgF_3cn-(-0.001801*νd_3cn+0.648262)>0.016 ...(6)''

In the optical system according to one embodiment, it is desirable that the 3c group GR3c includes at least one negative lens that satisfies the following conditional expression (7).
νd_3cn<31...(7)
however,
νd_3cn: Abbe number for the d-line of the negative lens in the 3c group GR3c.

By using an anomalous dispersion glass material that satisfies conditional expression (7) for the negative lens in group 3c GR3c, lateral chromatic aberration is well corrected, resulting in good imaging performance even at the periphery. Exceeding the upper limit of conditional expression (7) results in insufficient correction of primary and secondary chromatic aberration, resulting in a deterioration in imaging performance across the entire frame.

In order to more effectively realize the effect of the above-mentioned conditional expression (7), it is more desirable to set the numerical range of the conditional expression (7) as shown in the following conditional expression (7)'.
νd_3cn<28...(7)'

Even more preferably, the numerical range of conditional expression (7) should be set as in the following conditional expression (7)''.
νd_3cn<25...(7)''

In the optical system according to one embodiment, it is desirable that the 3c group GR3c includes at least one negative lens that satisfies the following conditional expression (8).
0<|f3cn/f|<0.15...(8)
however,
f3cn: focal length of the negative lens in the 3c group GR3c; f: focal length of the entire system when focused at infinity.

By placing a negative lens in group 3c GR3c that satisfies the focal length specified in conditional expression (8), lateral chromatic aberration in the peripheral areas is corrected more effectively, allowing for good imaging performance even in the peripheral areas. If the upper limit of conditional expression (8) is exceeded, the negative lens loses its function and is unable to provide chromatic aberration correction. If the lower limit of conditional expression (8) is exceeded, the power of the negative lens becomes too strong, resulting in poor correction of field curvature, astigmatism, and distortion.

In order to more effectively realize the effect of the above-mentioned conditional expression (8), it is more desirable to set the numerical range of the conditional expression (8) as shown in the following conditional expression (8)'.
0<|f3cn/f|<0.13...(8)'

Even more preferably, the numerical range of conditional expression (8) should be set as in the following conditional expression (8)''.
0<|f3cn/f|<0.10...(8)''

In an optical system according to one embodiment, it is desirable that the 3c group GR3c include at least one negative lens element that simultaneously satisfies any one of the above-mentioned conditional expressions (6), (7), and (8) and the following conditional expression (9):
D_3cnImg/f<0.15...(9)
however,
f: focal length of the entire system when focused at infinity; D_3cnImg: distance between the vertex of the surface of the negative lens in the 3c group GR3c on the object side and the image plane Simg.

By positioning a negative lens element with high chromatic aberration correction capabilities closer to the image plane so that either one of the above conditional expressions (6), (7), or (8) and conditional expression (9) are simultaneously satisfied, chromatic aberration is suppressed across the entire image plane, resulting in high imaging performance. If the upper limit of conditional expression (9) is exceeded, the negative lens element will be farther away from the image plane Simg, resulting in insufficient chromatic aberration correction capabilities.

In order to more effectively realize the effect of the above-mentioned conditional expression (9), it is more desirable to set the numerical range of the conditional expression (9) as shown in the following conditional expression (9)'.
D_3cnImg/f<0.14...(9)'

Even more preferably, the numerical range of conditional expression (9) should be set as in the following conditional expression (9)''.
D_3cnImg/f<0.12...(9)''

In the optical system according to one embodiment, it is desirable that the first lens group GR1 has at least one negative lens that satisfies the following conditional expressions (10) and (11).
νd_1n<35...(10)
θgF_1n-(-0.001801*νd_1n+0.648262)<0.010...(11)
however,
νd_1n: Abbe number for the d-line of the negative lens in the first lens group GR1. θgF_1n: partial dispersion ratio for the g-line and F-line of the negative lens in the first lens group GR1.

By using a glass material with dispersion characteristics that satisfy conditional expressions (10) and (11) for the negative lens in the first lens group GR1, chromatic aberration, which is a problem in telephoto lenses, can be effectively corrected. Exceeding the upper limit of conditional expression (10) results in insufficient correction of first- and second-order chromatic aberrations, degrading imaging performance across the entire image field. Exceeding the upper limit of conditional expression (11) results in insufficient correction of second-order chromatic aberrations, degrading imaging performance across the entire image field.

In order to better realize the effects of the above-described conditional expressions (10) and (11), it is more desirable to set the numerical ranges of the conditional expressions (10) and (11) as shown in the following conditional expressions (10)′ and (11)′.
νd_1n<32...(10)'
θgF_1n-(-0.001801*νd_1n+0.648262)<0.009...(11)'

Even more preferably, the numerical range of conditional expression (10) should be set as in the following conditional expression (10)''.
νd_1n<27...(10)''

Moreover, it is desirable that the optical system according to one embodiment satisfies the following conditional expression (12).
0.05<|f3c/f|<0.3...(12)
however,
f3c: focal length of the 3c group GR3c; f: focal length of the entire system when focused at infinity.

By setting the focal length of the 3c group GR3c within a range that satisfies conditional expression (12), it is possible to obtain good optical performance during image stabilization while maintaining image stabilization sensitivity at a value appropriate for the image stabilization group. If the lower limit of conditional expression (12) is exceeded, the power of the 3c group GR3c becomes excessive, and the correction of field curvature, astigmatism, and distortion aberrations deteriorates. If the upper limit of conditional expression (12) is exceeded, the power of the 3c group GR3c becomes too weak, making it difficult to lower the image stabilization group rearward while maintaining high optical performance during image stabilization.

In order to more effectively realize the effect of the above-mentioned conditional expression (12), it is more desirable to set the numerical range of the conditional expression (12) as shown in the following conditional expression (12).
0.05<|f3c/f|<0.15...(12)'

Furthermore, in an optical system according to one embodiment, it is desirable that the second lens group GR2 be composed of a cemented lens or a single lens. This makes it possible to obtain a lightweight focusing group, and to achieve high-speed, high-tracking AF (autofocus) performance.

3. Application example to imaging device
Next, a specific example of application of the optical system according to the embodiment of the present disclosure to an imaging device will be described.

Figure 45 shows an example configuration of an imaging device 100 to which an optical system according to one embodiment is applied. This imaging device 100 is, for example, a digital still camera, and includes a camera block 10, a camera signal processing unit 20, an image processing unit 30, an LCD (Liquid Crystal Display) 40, an R/W (Reader/Writer) 50, a CPU (Central Processing Unit) 60, an input unit 70, and a lens drive control unit 80.

The camera block 10 is responsible for the imaging function and has an optical system including an imaging lens 110 and an imaging element 12 such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor). The imaging element 12 converts the optical image formed by the imaging lens 110 into an electrical signal, and outputs an imaging signal (image signal) corresponding to the optical image. The optical systems 1 to 11 according to the configuration examples shown in Figure 1 and elsewhere can be used as the imaging lens 110.

The camera signal processing unit 20 performs various signal processing operations on the image signal output from the image sensor 12, such as analog-to-digital conversion, noise removal, image quality correction, and conversion to luminance and color difference signals.

The image processing unit 30 performs recording and playback processing of image signals, including compression, encoding, decompression, and decoding of image signals based on a predetermined image data format, as well as conversion of data specifications such as resolution.

The LCD 40 has the function of displaying various data such as the user's operation status on the input unit 70 and captured images. The R/W 50 writes image data encoded by the image processing unit 30 to the memory card 1000 and reads image data recorded on the memory card 1000. The memory card 1000 is, for example, a semiconductor memory that can be inserted into and removed from a slot connected to the R/W 50.

The CPU 60 functions as a control processing unit that controls each circuit block provided in the imaging device 100, and controls each circuit block based on instruction input signals and the like from the input unit 70. The input unit 70 consists of various switches and the like that are operated as required by the user. The input unit 70 is composed of, for example, a shutter release button for operating the shutter and a selection switch for selecting an operating mode, and is configured to output instruction input signals to the CPU 60 in response to user operations. The lens drive control unit 80 controls the drive of the lenses arranged in the camera block 10, and is configured to control motors and the like (not shown) that drive each lens of the imaging lens 110 based on control signals from the CPU 60.

The operation of the imaging device 100 will be described below.
In a standby state for photographing, under the control of the CPU 60, an image signal photographed by the camera block 10 is output to the LCD 40 via the camera signal processing unit 20 and displayed as a camera-through image. Furthermore, when an instruction input signal for zooming or focusing is input from the input unit 70, the CPU 60 outputs a control signal to the lens drive control unit 80, and a predetermined lens of the imaging lens 110 moves under the control of the lens drive control unit 80.

When the shutter (not shown) of the camera block 10 is operated by an instruction input signal from the input unit 70, the captured image signal is output from the camera signal processing unit 20 to the image processing unit 30, where it is compressed and encoded and converted into digital data in a specified data format. The converted data is output to the R/W 50 and written to the memory card 1000.

Focusing is performed by the lens drive control unit 80 moving a specific lens of the imaging lens 110 based on a control signal from the CPU 60, for example, when the shutter release button on the input unit 70 is pressed halfway or fully pressed for recording (photography).

When playing back image data recorded on the memory card 1000, the R/W 50 reads out the specified image data from the memory card 1000 in response to an operation on the input unit 70, and the image processing unit 30 performs decompression and decoding processing. After that, the playback image signal is output to the LCD 40, and the playback image is displayed.

In the above-described embodiment, an example was shown in which the imaging device was applied to a digital still camera, but the application range of the imaging device is not limited to digital still cameras and it can be applied to various other imaging devices. For example, it can be applied to digital single-lens reflex cameras, digital non-reflex cameras, digital video cameras, surveillance cameras, etc. It can also be widely used as the camera section of digital input/output devices such as mobile phones with built-in cameras and information terminals with built-in cameras. It can also be applied to cameras with interchangeable lenses.

<4. Numerical examples of lenses>
Next, specific numerical examples of the optical system according to the embodiment of the present disclosure will be described. Here, examples will be described in which specific numerical values are applied to the optical systems 1 to 11 according to the configuration examples shown in FIG.

The symbols used in the tables and explanations below have the following meanings: "Si" indicates the surface number, which refers to the ith surface counting from the object side. "ri" indicates the radius of curvature of the ith surface counting from the object side (unit: mm). "di" indicates the axial surface spacing between the ith surface and the (i+1)th surface counting from the object side (unit: mm). "ndi" indicates the refractive index at the d-line (wavelength 587.6 nm) of the glass material or material that has the ith surface on the object side. "νdi" indicates the Abbe number at the d-line of the glass material or material that has the ith surface on the object side. "θgF" indicates the partial dispersion ratio between the g-line (wavelength 435.8 nm) and the F-line (wavelength 486.1 nm). "∞" in the radius of curvature indicates that the surface is flat. "STO" in the surface number column indicates that the aperture stop St is located at the corresponding position. "f" indicates the focal length of the entire lens system (unit: mm). "Fno" indicates the maximum aperture (F-number). "ω" indicates the half angle of view (unit: °). "Y" indicates the image height (unit: mm). "L" indicates the total lens length (the distance from the surface of the optical system closest to the object to the image plane) (unit: mm). "BF" indicates the back focus (unit: mm).

[Configuration common to each embodiment]
The optical systems 1 to 11 to which the following Examples 1 to 11 are applied all have a configuration that satisfies the above-mentioned <1. Basic lens configuration>.

That is, each of optical systems 1 to 11 is composed of a first lens group GR1, a second lens group GR2, and a third lens group GR3.

The first lens group GR1 as a whole has positive refractive power, and the entire group is fixed relative to the image plane Simg during focusing.

The second lens group GR2 has positive or negative refractive power as a whole, and focuses from infinity to close distances by moving the entire group along the optical axis.

The third lens group GR3 has negative or positive refractive power as a whole, and is fixed relative to the image plane Simg during focusing. The third lens group GR3 is further divided, from the object side to the image plane side, into the 3a group GR3a, the 3b group GR3b, and the 3c group GR3c. The 3b group GR3b is an image stabilization group that compensates for image blur by moving in a direction approximately perpendicular to the optical axis Z1.

Aperture stop St is located between group 3a GR3a and group 3b GR3b.

[Example 1]
Table 1 shows basic lens data for Example 1, in which specific values are applied to the optical system 1 shown in Fig. 1. Table 2 shows values for focal length (f), F-number (Fno), half angle of view (ω), image height (Y), total lens length (L), and back focus (BF) when focusing at infinity. Table 3 shows values for surface spacing that are variable when focusing at infinity and when focusing at close range.

In the optical system 1 according to Example 1, the first lens group GR1 is composed of seven lenses, lenses L11 to L17, in order from the object side to the image plane side. The largest air gap on the optical axis within the first lens group GR1 is between lenses L11 and L12.

In the optical system 1 according to Example 1, the second lens group GR2 is composed of a cemented lens consisting of, in order from the object side to the image plane side, a lens L21 and a lens L22. The second lens group GR2 as a whole has positive refractive power, and when focusing from infinity to a close distance, the second lens group GR2 moves toward the object side.

In the optical system 1 according to Example 1, the third lens group GR3 is composed of, in order from the object side to the image plane side, lenses L31 to L43. The 3a group GR3a is composed of lenses L31 and L32. The 3b group GR3b is composed of lenses L33 to L35. The 3c group GR3c is composed of lenses L36 to L43. The third lens group GR3 has negative refractive power as a group as a whole.

Figure 2 shows the longitudinal aberration of the optical system 1 according to Example 1 when focused at infinity. Figure 2 shows the longitudinal aberrations, including spherical aberration, astigmatism (field curvature), and distortion. In the spherical aberration diagram, the dashed-dotted line indicates values for the C-line (wavelength 545.3 nm), the solid line indicates values for the d-line (wavelength 587.6 nm), and the dashed line indicates values for the g-line (wavelength 435.8 nm). In the astigmatism diagram, the solid line (S) indicates values for the sagittal image plane of the d-line, and the dashed-dotted line (T) indicates values for the tangential image plane of the d-line. In the distortion diagram, values for the d-line are shown. Also, Figures 3 and 4 show the lateral aberration of the optical system 1 according to Example 1 when focused at infinity. Figure 3 shows the lateral aberration without image stabilization, and Figure 4 shows the lateral aberration with image stabilization. In the lateral aberration diagram, y indicates the image height, Δy indicates the lateral aberration in the tangential direction, and Δx indicates the lateral aberration in the sagittal direction. The same applies to the aberration diagrams in the other examples that follow.

As can be seen from each aberration diagram, the optical system 1 according to Example 1 is lightweight, has a center of gravity close to the imaging plane, and is easy to maneuver, providing good optical performance with chromatic aberrations and other aberrations suppressed across the entire image field. Furthermore, in the telephoto range, it provides sufficient image stabilization while producing high-quality images.

[Example 2]
Table 4 shows basic lens data for Example 2, in which specific values are applied to the optical system 2 shown in Figure 5. Table 5 also shows values for the focal length (f), F-number (Fno), half angle of view (ω), image height (Y), total lens length (L), and back focus (BF) when focusing at infinity. Table 6 shows values for the surface spacing that are variable when focusing at infinity and when focusing at close range.

In the optical system 2 according to Example 2, the first lens group GR1 is composed of seven lenses, lenses L11 to L17, in order from the object side to the image plane side. The largest air gap on the optical axis within the first lens group GR1 is between lenses L11 and L12.

In the optical system 2 according to Example 2, the second lens group GR2 is composed of a cemented lens consisting of, in order from the object side to the image plane side, a lens L21 and a lens L22. The second lens group GR2 as a whole has positive refractive power, and when focusing from infinity to a close distance, the second lens group GR2 moves toward the object side.

In the optical system 2 according to Example 2, the third lens group GR3 is composed of, in order from the object side to the image plane side, lenses L31 to L43. The 3a group GR3a is composed of lenses L31 and L32. The 3b group GR3b is composed of lenses L33 to L35. The 3c group GR3c is composed of lenses L36 to L43. The third lens group GR3 has negative refractive power as a group as a whole.

Figure 6 shows the longitudinal aberration of the optical system 2 according to Example 2 when focused at infinity. Figures 7 and 8 show the lateral aberration of the optical system 2 according to Example 2 when focused at infinity.

As can be seen from each aberration diagram, the optical system 2 according to Example 2 is lightweight, has a center of gravity close to the imaging plane, and is easy to maneuver, providing good optical performance with chromatic aberrations and other aberrations suppressed across the entire image field. Furthermore, in the telephoto range, it provides sufficient image stabilization while producing high-quality images.

[Example 3]
Table 7 shows basic lens data for Example 3, in which specific values are applied to the optical system 3 shown in Figure 9. Table 8 shows values for the focal length (f), F-number (Fno), half angle of view (ω), image height (Y), total lens length (L), and back focus (BF) when focusing at infinity. Table 9 shows values for the surface spacing that is variable when focusing at infinity and when focusing at close range.

In the optical system 3 according to Example 3, the first lens group GR1 is composed of seven lenses, lenses L11 to L17, in order from the object side to the image plane side. The largest air gap on the optical axis within the first lens group GR1 is between lenses L11 and L12.

In the optical system 3 according to Example 3, the second lens group GR2 is composed of a cemented lens consisting of, in order from the object side to the image plane side, a lens L21 and a lens L22. The second lens group GR2 as a whole has positive refractive power, and when focusing from infinity to a close distance, the second lens group GR2 moves toward the object side.

In the optical system 3 according to Example 3, the third lens group GR3 is composed of, in order from the object side to the image plane side, lenses L31 to L44. The 3a group GR3a is composed of lenses L31 and L32. The 3b group GR3b is composed of lenses L33 to L35. The 3c group GR3c is composed of lenses L36 to L44. The third lens group GR3 has negative refractive power as a group as a whole.

Figure 10 shows the longitudinal aberration when the optical system 3 according to Example 3 is focused at infinity. Figures 11 and 12 show the lateral aberration when the optical system 3 according to Example 3 is focused at infinity.

As can be seen from each aberration diagram, the optical system 3 according to Example 3 is lightweight, has a center of gravity close to the imaging plane, and is easy to maneuver, providing good optical performance with chromatic aberrations and other aberrations suppressed across the entire image field. Furthermore, in the telephoto range, it provides sufficient image stabilization while producing high-quality images.

[Example 4]
Table 10 shows basic lens data for Example 4, in which specific values are applied to the optical system 4 shown in Figure 13. Table 11 shows values for the focal length (f), F-number (Fno), half angle of view (ω), image height (Y), total lens length (L), and back focus (BF) when focusing at infinity. Table 12 shows values for the surface spacing that are variable when focusing at infinity and when focusing at close range.

In the optical system 4 according to Example 4, the first lens group GR1 is composed of seven lenses, lenses L11 to L17, in order from the object side to the image plane side. The largest air gap on the optical axis within the first lens group GR1 is between lenses L11 and L12.

In the optical system 4 according to Example 4, the second lens group GR2 is composed of a cemented lens consisting of, in order from the object side to the image plane side, a lens L21 and a lens L22. The second lens group GR2 as a whole has positive refractive power, and when focusing from infinity to a close distance, the second lens group GR2 moves toward the object side.

In the optical system 4 according to Example 4, the third lens group GR3 is composed of, in order from the object side to the image plane side, lenses L31 to L44. The 3a group GR3a is composed of lenses L31 and L32. The 3b group GR3b is composed of lenses L33 to L35. The 3c group GR3c is composed of lenses L36 to L44. The third lens group GR3 has negative refractive power as a group as a whole.

Figure 14 shows the longitudinal aberration when the optical system 4 according to Example 4 is focused at infinity. Figures 15 and 16 show the lateral aberration when the optical system 4 according to Example 4 is focused at infinity.

As can be seen from each aberration diagram, the optical system 4 according to Example 4 is lightweight, has a center of gravity close to the imaging plane, and is easy to maneuver, providing good optical performance with chromatic aberrations and other aberrations suppressed across the entire image field. Furthermore, in the telephoto range, it provides sufficient image stabilization while producing high-quality images.

[Example 5]
Table 13 shows basic lens data for Example 5, in which specific values are applied to the optical system 5 shown in Figure 17. Table 14 shows values for the focal length (f), F-number (Fno), half angle of view (ω), image height (Y), total lens length (L), and back focus (BF) when focusing at infinity. Table 15 shows values for the surface spacing that are variable when focusing at infinity and when focusing at close range.

In the optical system 5 according to Example 5, the first lens group GR1 is composed of seven lenses, lenses L11 to L17, in order from the object side to the image plane side. The largest air gap on the optical axis within the first lens group GR1 is between lenses L11 and L12.

In the optical system 5 according to Example 5, the second lens group GR2 is composed of a cemented lens consisting of, in order from the object side to the image plane side, a lens L21 and a lens L22. The second lens group GR2 as a whole has positive refractive power, and when focusing from infinity to a close distance, the second lens group GR2 moves toward the object side.

In the optical system 5 according to Example 5, the third lens group GR3 is composed of, in order from the object side to the image plane side, lenses L31 to L43. The 3a group GR3a is composed of lenses L31 and L32. The 3b group GR3b is composed of lenses L33 to L35. The 3c group GR3c is composed of lenses L36 to L43. The third lens group GR3 has negative refractive power as a group as a whole.

Figure 18 shows the longitudinal aberration when the optical system 5 according to Example 5 is focused at infinity. Figures 19 and 20 show the lateral aberration when the optical system 5 according to Example 5 is focused at infinity.

As can be seen from each aberration diagram, optical system 5 according to Example 5 is lightweight, has a center of gravity close to the imaging plane, and is easy to maneuver, providing good optical performance with chromatic aberrations and other aberrations suppressed across the entire image field. Furthermore, it provides a high-quality image while fully demonstrating image stabilization effects in the telephoto range.

[Example 6]
Table 16 shows basic lens data for Example 6, in which specific values are applied to the optical system 6 shown in Figure 21. Table 17 shows values for focal length (f), F-number (Fno), half angle of view (ω), image height (Y), total lens length (L), and back focus (BF) when focusing at infinity. Table 18 shows values for surface spacing that are variable when focusing at infinity and when focusing at close range.

In the optical system 6 according to Example 6, the first lens group GR1 is composed of seven lenses, lenses L11 to L17, in order from the object side to the image plane side. The largest air gap on the optical axis within the first lens group GR1 is between lenses L11 and L12.

In the optical system 6 according to Example 6, the second lens group GR2 is composed of a single lens (lens L21). The second lens group GR2 as a whole has positive refractive power, and when focusing from infinity to a close distance, the second lens group GR2 moves toward the object side.

In the optical system 6 according to Example 6, the third lens group GR3 is composed of, in order from the object side to the image plane side, lenses L31 to L45. The 3a group GR3a is composed of lenses L31 and L32. The 3b group GR3b is composed of lenses L33 to L35. The 3c group GR3c is composed of lenses L36 to L45. The third lens group GR3 has negative refractive power as a group as a whole.

Figure 22 shows the longitudinal aberration when the optical system 6 according to Example 6 is focused at infinity. Figures 23 and 24 show the transverse aberration when the optical system 6 according to Example 6 is focused at infinity.

As can be seen from each aberration diagram, the optical system 6 according to Example 6 is lightweight, has a center of gravity close to the imaging plane, and is easy to maneuver, providing good optical performance with chromatic aberrations and other aberrations suppressed across the entire image field. Furthermore, in the telephoto range, it provides sufficient image stabilization while producing high-quality images.

[Example 7]
Table 19 shows basic lens data for Example 7, in which specific values are applied to the optical system 7 shown in Figure 25. Table 20 shows values for the focal length (f), F-number (Fno), half angle of view (ω), image height (Y), total lens length (L), and back focus (BF) when focusing at infinity. Table 21 shows values for the surface spacing that are variable when focusing at infinity and when focusing at close range.

In the optical system 7 according to Example 7, the first lens group GR1 is composed of six lenses, lenses L11 to L16, in that order from the object side to the image plane side. The largest air gap on the optical axis within the first lens group GR1 is between lenses L11 and L12.

In the optical system 7 according to Example 7, the second lens group GR2 is composed of a single lens (lens L21). The second lens group GR2 as a whole has negative refractive power, and when focusing from infinity to a close distance, the second lens group GR2 moves toward the image plane.

In the optical system 7 according to Example 7, the third lens group GR3 is composed of, in order from the object side to the image plane side, lenses L31 to L45. The 3a group GR3a is composed of lenses L31 to L34. The 3b group GR3b is composed of lenses L35 to L37. The 3c group GR3c is composed of lenses L38 to L45. The third lens group GR3 has negative refractive power as a group as a whole.

Figure 26 shows the longitudinal aberration when the optical system 7 according to Example 7 is focused at infinity. Figures 27 and 28 show the transverse aberration when the optical system 7 according to Example 7 is focused at infinity.

As can be seen from each aberration diagram, optical system 7 according to Example 7 is lightweight, has a center of gravity close to the imaging plane, and is easy to maneuver, providing good optical performance with chromatic aberrations and other aberrations suppressed across the entire image field. Furthermore, it provides a high-quality image while fully demonstrating image stabilization effects in the telephoto range.

[Example 8]
Table 22 shows basic lens data for Example 8, in which specific values are applied to the optical system 8 shown in Figure 29. Table 23 shows values for focal length (f), F-number (Fno), half angle of view (ω), image height (Y), total lens length (L), and back focus (BF) when focusing at infinity. Table 24 shows values for surface spacing that are variable between focusing at infinity and when focusing at close range.

In the optical system 8 according to Example 8, the first lens group GR1 is composed of six lenses, lenses L11 to L16, in that order from the object side to the image plane side. The largest air gap on the optical axis within the first lens group GR1 is between lenses L11 and L12.

In the optical system 8 according to Example 8, the second lens group GR2 is composed of a single lens (lens L21). The second lens group GR2 as a whole has negative refractive power, and when focusing from infinity to a close distance, the second lens group GR2 moves toward the image plane.

In the optical system 8 according to Example 8, the third lens group GR3 is composed of, in order from the object side to the image plane side, lenses L31 to L46. The 3a group GR3a is composed of lenses L31 to L34. The 3b group GR3b is composed of lenses L35 to L37. The 3c group GR3c is composed of lenses L38 to L46. The third lens group GR3 has negative refractive power as a group as a whole.

Figure 30 shows the longitudinal aberration when the optical system 8 according to Example 8 is focused at infinity. Figures 31 and 32 show the transverse aberration when the optical system 8 according to Example 8 is focused at infinity.

As can be seen from each aberration diagram, the optical system 8 according to Example 8 is lightweight, has a center of gravity close to the imaging plane, and is easy to maneuver, providing good optical performance with chromatic aberrations and other aberrations suppressed across the entire image field. Furthermore, it provides a high-quality image while fully demonstrating image stabilization effects in the telephoto range.

[Example 9]
Table 25 shows basic lens data for Example 9, in which specific values are applied to the optical system 9 shown in Figure 33. Table 26 shows values for focal length (f), F-number (Fno), half angle of view (ω), image height (Y), total lens length (L), and back focus (BF) when focusing at infinity. Table 27 shows values for surface spacing that are variable between focusing at infinity and when focusing at close range.

In the optical system 9 according to Example 9, the first lens group GR1 is composed of six lenses, lenses L11 to L16, in that order from the object side to the image plane side. The largest air gap on the optical axis within the first lens group GR1 is between lenses L11 and L12.

In the optical system 9 according to Example 9, the second lens group GR2 is composed of a single lens (lens L21). The second lens group GR2 as a whole has negative refractive power, and when focusing from infinity to a close distance, the second lens group GR2 moves toward the image plane.

In the optical system 9 according to Example 9, the third lens group GR3 is composed of, in order from the object side to the image plane side, lenses L31 to L46. The 3a group GR3a is composed of lenses L31 to L34. The 3b group GR3b is composed of lenses L35 to L37. The 3c group GR3c is composed of lenses L38 to L46. The third lens group GR3 has negative refractive power as a group as a whole.

Figure 34 shows the longitudinal aberration when focusing at infinity in the optical system 9 according to Example 9. Figures 35 and 36 show the transverse aberration when focusing at infinity in the optical system 9 according to Example 9.

As can be seen from each aberration diagram, the optical system 9 according to Example 9 is lightweight, has a center of gravity close to the imaging plane, and is easy to maneuver, providing good optical performance with chromatic aberrations and other aberrations suppressed across the entire image field. Furthermore, it provides a high-quality image while fully demonstrating image stabilization effects in the telephoto range.

[Example 10]
Table 28 shows basic lens data for Example 10, in which specific values are applied to the optical system 10 shown in Figure 37. Table 29 shows values for focal length (f), F-number (Fno), half angle of view (ω), image height (Y), total lens length (L), and back focus (BF) when focusing at infinity. Table 30 shows values for surface spacing that are variable when focusing at infinity and when focusing at close range.

In the optical system 10 according to Example 10, the first lens group GR1 is composed of six lenses, lenses L11 to L16, in that order from the object side to the image plane side. The largest air gap on the optical axis within the first lens group GR1 is between lenses L11 and L12.

In the optical system 10 according to Example 10, the second lens group GR2 is composed of a cemented lens consisting of, in order from the object side to the image plane side, a lens L21 and a lens L22. The second lens group GR2 as a whole has negative refractive power, and when focusing from infinity to a close distance, the second lens group GR2 moves toward the image plane side.

In the optical system 10 according to Example 10, the third lens group GR3 is composed of, in order from the object side to the image plane side, lenses L31 to L46. The 3a group GR3a is composed of lenses L31 to L34. The 3b group GR3b is composed of lenses L35 to L37. The 3c group GR3c is composed of lenses L38 to L46. The third lens group GR3 has negative refractive power as a group as a whole.

Figure 38 shows the longitudinal aberration when focusing at infinity in the optical system 10 according to Example 10. Figures 39 and 40 show the transverse aberration when focusing at infinity in the optical system 10 according to Example 10.

As can be seen from each aberration diagram, the optical system 10 according to Example 10 is lightweight, has a center of gravity close to the imaging plane, and is easy to maneuver, providing good optical performance with chromatic aberrations and other aberrations suppressed across the entire image field. Furthermore, in the telephoto range, it provides sufficient image stabilization while producing high-quality images.

[Example 11]
Table 31 shows basic lens data for Example 11, in which specific values are applied to the optical system 11 shown in Figure 41. Table 32 shows values for focal length (f), F-number (Fno), half angle of view (ω), image height (Y), total lens length (L), and back focus (BF) when focusing at infinity. Table 33 shows values for surface spacing that are variable between focusing at infinity and focusing at close distances.

In the optical system 11 according to Example 11, the first lens group GR1 is composed of six lenses, lenses L11 to L16, in that order from the object side to the image plane side. The largest air gap on the optical axis within the first lens group GR1 is between lenses L11 and L12.

In the optical system 11 of Example 11, the second lens group GR2 is composed of a cemented lens consisting of, in order from the object side to the image plane side, a lens L21 and a lens L22. The second lens group GR2 as a whole has negative refractive power, and when focusing from infinity to a close distance, the second lens group GR2 moves toward the image plane side.

In the optical system 11 according to Example 11, the third lens group GR3 is composed of, in order from the object side to the image plane side, lenses L31 to L46. The 3a group GR3a is composed of lenses L31 to L34. The 3b group GR3b is composed of lenses L35 to L37. The 3c group GR3c is composed of lenses L38 to L46. The third lens group GR3 has positive refractive power as a group as a whole.

Figure 42 shows the longitudinal aberration when the optical system 11 of Example 11 is focused at infinity. Figures 43 and 44 show the transverse aberration when the optical system 11 of Example 11 is focused at infinity.

As can be seen from each aberration diagram, the optical system 11 according to Example 11 is lightweight, has a center of gravity close to the imaging plane, and is easy to maneuver, providing good optical performance with chromatic aberrations and other aberrations suppressed across the entire image field. Furthermore, in the telephoto range, it provides sufficient image stabilization while producing high-quality images.

[Other Numerical Data for Each Example]
Tables 34 to 41 show a summary of the values for each of the above-mentioned conditional expressions for each example. In Tables 34 to 41, the lenses that satisfy each conditional expression are listed together with their numerical values, as appropriate. As can be seen from Tables 34 to 41, the values for each example fall within the numerical range for each conditional expression.

<5. Application Examples>
[5.1 First Application Example]
The technology according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of moving body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, a robot, construction machinery, or agricultural machinery (tractor).

FIG. 46 is a block diagram showing a schematic configuration example of a vehicle control system 7000, which is an example of a mobile object control system to which the technology disclosed herein can be applied. The vehicle control system 7000 includes multiple electronic control units connected via a communication network 7010. In the example shown in FIG. 46, the vehicle control system 7000 includes a drive system control unit 7100, a body system control unit 7200, a battery control unit 7300, an outside-vehicle information detection unit 7400, an inside-vehicle information detection unit 7500, and an integrated control unit 7600. The communication network 7010 connecting these multiple control units may be an in-vehicle communication network conforming to any standard, such as CAN (Controller Area Network), LIN (Local Interconnect Network), LAN (Local Area Network), or FlexRay (registered trademark).

Each control unit includes a microcomputer that performs arithmetic processing according to various programs, a memory unit that stores the programs executed by the microcomputer or parameters used in various calculations, and a drive circuit that drives various controlled devices. Each control unit includes a network I/F for communicating with other control units via the communication network 7010, as well as a communication I/F for communicating with devices or sensors inside and outside the vehicle via wired or wireless communication. Figure 46 illustrates the functional configuration of the integrated control unit 7600, including a microcomputer 7610, a general-purpose communication I/F 7620, a dedicated communication I/F 7630, a positioning unit 7640, a beacon receiving unit 7650, an in-vehicle device I/F 7660, an audio/video output unit 7670, an in-vehicle network I/F 7680, and a memory unit 7690. Other control units similarly include microcomputers, communication I/Fs, memory units, etc.

The drivetrain control unit 7100 controls the operation of devices related to the vehicle's drivetrain in accordance with various programs. For example, the drivetrain control unit 7100 functions as a control device for a driveforce generating device such as an internal combustion engine or drive motor that generates vehicle driveforce, a driveforce transmission mechanism that transmits driveforce to the wheels, a steering mechanism that adjusts the vehicle's steering angle, and a braking device that generates vehicle braking force. The drivetrain control unit 7100 may also function as a control device for an ABS (Antilock Brake System) or ESC (Electronic Stability Control), etc.

A vehicle state detection unit 7110 is connected to the drivetrain control unit 7100. The vehicle state detection unit 7110 includes, for example, at least one of a gyro sensor that detects the angular velocity of the axial rotational motion of the vehicle body, an acceleration sensor that detects the acceleration of the vehicle, or a sensor for detecting the amount of operation of the accelerator pedal, the amount of operation of the brake pedal, the steering angle of the steering wheel, the engine rotation speed, or the rotation speed of the wheels. The drivetrain control unit 7100 performs arithmetic processing using signals input from the vehicle state detection unit 7110, and controls the internal combustion engine, drive motor, electric power steering device, brake device, etc.

The body system control unit 7200 controls the operation of various devices installed in the vehicle body according to various programs. For example, the body system control unit 7200 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 7200. The body system control unit 7200 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

The battery control unit 7300 controls the secondary battery 7310, which is the power supply source for the drive motor, in accordance with various programs. For example, information such as battery temperature, battery output voltage, and remaining battery capacity is input to the battery control unit 7300 from a battery device equipped with the secondary battery 7310. The battery control unit 7300 performs calculations using these signals to regulate the temperature of the secondary battery 7310 or control cooling devices and other devices equipped in the battery device.

The outside vehicle information detection unit 7400 detects information outside the vehicle equipped with the vehicle control system 7000. For example, the outside vehicle information detection unit 7400 is connected to at least one of an imaging unit 7410 and an outside vehicle information detection unit 7420. The imaging unit 7410 includes at least one of a ToF (Time Of Flight) camera, a stereo camera, a monocular camera, an infrared camera, and other cameras. The outside vehicle information detection unit 7420 includes at least one of, for example, an environmental sensor for detecting the current weather or climate, or a surrounding information detection sensor for detecting other vehicles, obstacles, pedestrians, etc. around the vehicle equipped with the vehicle control system 7000.

The environmental sensor may be, for example, at least one of a raindrop sensor that detects rain, a fog sensor that detects fog, a sunshine sensor that detects the level of sunlight, and a snow sensor that detects snowfall. The surrounding information detection sensor may be at least one of an ultrasonic sensor, a radar device, and a LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) device. The imaging unit 7410 and the outside vehicle information detection unit 7420 may each be provided as an independent sensor or device, or may be provided as a device that integrates multiple sensors or devices.

Here, Figure 47 shows an example of the installation locations of the imaging unit 7410 and the vehicle exterior information detection unit 7420. The imaging units 7910, 7912, 7914, 7916, and 7918 are installed, for example, at least one of the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle cabin of the vehicle 7900. The imaging unit 7910 installed on the front nose and the imaging unit 7918 installed on the upper part of the windshield inside the vehicle cabin mainly capture images of the front of the vehicle 7900. The imaging units 7912 and 7914 installed on the side mirrors mainly capture images of the sides of the vehicle 7900. The imaging unit 7916 installed on the rear bumper or back door mainly captures images of the rear of the vehicle 7900. The imaging unit 7918 installed on the upper part of the windshield inside the vehicle cabin is mainly used to detect leading vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

Note that Figure 47 shows an example of the imaging ranges of each of the imaging units 7910, 7912, 7914, and 7916. Imaging range a indicates the imaging range of the imaging unit 7910 provided on the front nose, imaging ranges b and c indicate the imaging ranges of the imaging units 7912 and 7914 provided on the side mirrors, respectively, and imaging range d indicates the imaging range of the imaging unit 7916 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 7910, 7912, 7914, and 7916, an overhead image of the vehicle 7900 viewed from above can be obtained.

External vehicle information detection units 7920, 7922, 7924, 7926, 7928, and 7930 installed on the front, rear, sides, corners, and above the windshield inside the vehicle 7900 may be, for example, ultrasonic sensors or radar devices. External vehicle information detection units 7920, 7926, and 7930 installed on the front nose, rear bumper, back door, and above the windshield inside the vehicle 7900 may be, for example, LIDAR devices. These external vehicle information detection units 7920 to 7930 are primarily used to detect preceding vehicles, pedestrians, obstacles, etc.

Returning to Figure 46, the explanation continues. The outside vehicle information detection unit 7400 causes the imaging unit 7410 to capture images outside the vehicle and receives the captured image data. The outside vehicle information detection unit 7400 also receives detection information from the connected outside vehicle information detection unit 7420. If the outside vehicle information detection unit 7420 is an ultrasonic sensor, radar device, or LIDAR device, the outside vehicle information detection unit 7400 emits ultrasonic waves or electromagnetic waves, and receives information on the received reflected waves. Based on the received information, the outside vehicle information detection unit 7400 may perform object detection processing or distance detection processing for people, vehicles, obstacles, signs, text on the road, etc. Based on the received information, the outside vehicle information detection unit 7400 may also perform environmental recognition processing to recognize rainfall, fog, road conditions, etc. Based on the received information, the outside vehicle information detection unit 7400 may calculate the distance to objects outside the vehicle.

The outside vehicle information detection unit 7400 may also perform image recognition processing or distance detection processing to recognize people, cars, obstacles, signs, or text on the road surface based on the received image data. The outside vehicle information detection unit 7400 may also perform processing such as distortion correction or alignment on the received image data, and may also generate an overhead image or panoramic image by combining image data captured by different image capture units 7410. The outside vehicle information detection unit 7400 may also perform viewpoint conversion processing using image data captured by different image capture units 7410.

The in-vehicle information detection unit 7500 detects information inside the vehicle. Connected to the in-vehicle information detection unit 7500 is, for example, a driver state detection unit 7510 that detects the driver's state. The driver state detection unit 7510 may include a camera that captures an image of the driver, a biosensor that detects the driver's biometric information, or a microphone that collects audio from within the vehicle cabin. The biosensor is provided, for example, on the seat or steering wheel, and detects the biometric information of a passenger sitting in the seat or the driver gripping the steering wheel. The in-vehicle information detection unit 7500 may calculate the driver's level of fatigue or concentration based on the detection information input from the driver state detection unit 7510, or may determine whether the driver is dozing off. The in-vehicle information detection unit 7500 may perform processing such as noise canceling on the collected audio signal.

The integrated control unit 7600 controls the overall operation of the vehicle control system 7000 in accordance with various programs. An input unit 7800 is connected to the integrated control unit 7600. The input unit 7800 may be implemented by a device that can be operated by an occupant, such as a touch panel, button, microphone, switch, or lever. Data obtained by voice recognition of voice input via a microphone may be input to the integrated control unit 7600. The input unit 7800 may be, for example, a remote control device that uses infrared or other radio waves, or an externally connected device such as a mobile phone or PDA (Personal Digital Assistant) that can operate the vehicle control system 7000. The input unit 7800 may be, for example, a camera, in which case the occupant can input information using gestures. Alternatively, data obtained by detecting the movement of a wearable device worn by the occupant may be input. Furthermore, the input unit 7800 may include, for example, an input control circuit that generates an input signal based on information input by the occupant using the input unit 7800 and outputs the signal to the integrated control unit 7600. By operating this input unit 7800, passengers and others can input various data and issue processing instructions to the vehicle control system 7000.

The storage unit 7690 may include a ROM (Read Only Memory) that stores various programs executed by the microcomputer, and a RAM (Random Access Memory) that stores various parameters, calculation results, sensor values, etc. The storage unit 7690 may also be implemented using a magnetic storage device such as an HDD (Hard Disc Drive), a semiconductor storage device, an optical storage device, or a magneto-optical storage device.

The general-purpose communication I/F 7620 is a general-purpose communication I/F that mediates communication between various devices present in the external environment 7750. The general-purpose communication I/F 7620 may implement cellular communication protocols such as GSM (registered trademark) (Global System of Mobile communications), WiMAX (registered trademark), LTE (registered trademark) (Long Term Evolution) or LTE-Advanced (LTE-A), or other wireless communication protocols such as wireless LAN (also known as Wi-Fi (registered trademark)) and Bluetooth (registered trademark). The general-purpose communication I/F 7620 may connect to devices (e.g., application servers or control servers) present on an external network (e.g., the Internet, a cloud network, or an operator-specific network) via, for example, a base station or access point. The general-purpose communication I/F 7620 may also connect to a terminal located near the vehicle (for example, a terminal of a driver, pedestrian, or store, or an MTC (Machine Type Communication) terminal) using, for example, P2P (Peer To Peer) technology.

The dedicated communication I/F 7630 is a communication I/F that supports communication protocols designed for use in vehicles. The dedicated communication I/F 7630 may implement standard protocols such as WAVE (Wireless Access in Vehicle Environment), which is a combination of the lower layer IEEE 802.11p and the upper layer IEEE 1609, DSRC (Dedicated Short Range Communications), or a cellular communication protocol. The dedicated communication I/F 7630 typically performs V2X communication, a concept that includes one or more of vehicle-to-vehicle communication, vehicle-to-infrastructure communication, vehicle-to-home communication, and vehicle-to-pedestrian communication.

The positioning unit 7640 performs positioning by receiving, for example, GNSS signals from GNSS (Global Navigation Satellite System) satellites (e.g., GPS signals from GPS (Global Positioning System) satellites), and generates location information including the vehicle's latitude, longitude, and altitude. The positioning unit 7640 may determine the current location by exchanging signals with a wireless access point, or may obtain location information from a terminal with positioning functionality, such as a mobile phone, PHS, or smartphone.

The beacon receiver 7650 receives, for example, radio waves or electromagnetic waves transmitted from radio stations installed on the road, and acquires information such as the current location, traffic congestion, road closures, and travel time. Note that the functions of the beacon receiver 7650 may be included in the dedicated communication I/F 7630 described above.

The in-vehicle device I/F 7660 is a communication interface that mediates connections between the microcomputer 7610 and various in-vehicle devices 7760 present in the vehicle. The in-vehicle device I/F 7660 may establish a wireless connection using a wireless communication protocol such as wireless LAN, Bluetooth (registered trademark), NFC (Near Field Communication), or WUSB (Wireless USB). The in-vehicle device I/F 7660 may also establish a wired connection via a connection terminal (and, if necessary, a cable) not shown, such as USB (Universal Serial Bus), HDMI (High-Definition Multimedia Interface), or MHL (Mobile High-Definition Link). The in-vehicle device 7760 may include, for example, at least one of a mobile device or wearable device owned by the passenger, or an information device carried or installed in the vehicle. The in-vehicle device 7760 may also include a navigation device that searches for a route to a desired destination. The in-vehicle device I/F 7660 exchanges control signals or data signals with these in-vehicle devices 7760.

The in-vehicle network I/F 7680 is an interface that mediates communication between the microcomputer 7610 and the communication network 7010. The in-vehicle network I/F 7680 sends and receives signals in accordance with a specific protocol supported by the communication network 7010.

The microcomputer 7610 of the integrated control unit 7600 controls the vehicle control system 7000 in accordance with various programs based on information acquired via at least one of the general-purpose communication I/F 7620, dedicated communication I/F 7630, positioning unit 7640, beacon receiving unit 7650, in-vehicle device I/F 7660, and in-vehicle network I/F 7680. For example, the microcomputer 7610 may calculate control target values for the driving force generating device, steering mechanism, or braking device based on acquired information from inside and outside the vehicle, and output control commands to the drivetrain control unit 7100. For example, the microcomputer 7610 may perform cooperative control aimed at realizing the functions of an Advanced Driver Assistance System (ADAS), including vehicle collision avoidance or impact mitigation, following driving based on inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, and vehicle lane departure warning. Furthermore, the microcomputer 7610 may perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation, by controlling the driving force generation device, steering mechanism, braking device, etc. based on the acquired information about the vehicle's surroundings.

The microcomputer 7610 may generate three-dimensional distance information between the vehicle and surrounding objects such as structures and people based on information acquired via at least one of the general-purpose communication I/F 7620, dedicated communication I/F 7630, positioning unit 7640, beacon receiving unit 7650, in-vehicle equipment I/F 7660, and in-vehicle network I/F 7680, and create local map information including information about the area around the vehicle's current location. Furthermore, the microcomputer 7610 may predict dangers such as a vehicle collision, approaching pedestrians, or entering a closed road based on the acquired information, and generate a warning signal. The warning signal may be, for example, a signal to generate a warning sound or turn on a warning lamp.

The audio/video output unit 7670 transmits at least one audio and/or visual output signal to an output device capable of visually or audibly notifying vehicle occupants or the outside of the vehicle of information. In the example of FIG. 46, an audio speaker 7710, a display unit 7720, and an instrument panel 7730 are illustrated as output devices. The display unit 7720 may include, for example, at least one of an on-board display and a head-up display. The display unit 7720 may have an AR (Augmented Reality) display function. The output device may also be other devices, such as headphones, a wearable device such as a glasses-type display worn by the occupant, a projector, or a lamp. When the output device is a display device, the display device visually displays the results obtained by various processes performed by the microcomputer 7610 or information received from other control units in various formats, such as text, images, tables, and graphs. When the output device is an audio output device, the audio output device converts audio signals consisting of reproduced audio data or acoustic data into analog signals and outputs them audibly.

In the example shown in FIG. 46, at least two control units connected via the communication network 7010 may be integrated into a single control unit. Alternatively, each control unit may be composed of multiple control units. Furthermore, the vehicle control system 7000 may include another control unit not shown. In the above description, some or all of the functions performed by one of the control units may be performed by another control unit. In other words, as long as information is sent and received via the communication network 7010, predetermined calculation processing may be performed by one of the control units. Similarly, a sensor or device connected to one of the control units may be connected to another control unit, and multiple control units may send and receive detection information to each other via the communication network 7010.

In the vehicle control system 7000 described above, the optical system and imaging device disclosed herein can be applied to the imaging unit 7410 and imaging units 7910, 7912, 7914, 7916, and 7918.

[5.2 Second Application Example]
The technology disclosed herein may be applied to an endoscopic surgery system.

Figure 48 is a diagram showing an example of the general configuration of an endoscopic surgery system 5000 to which the technology disclosed herein can be applied. Figure 48 shows an operator (doctor) 5067 performing surgery on a patient 5071 on a patient bed 5069 using the endoscopic surgery system 5000. As shown in the figure, the endoscopic surgery system 5000 is composed of an endoscope 5001, other surgical tools 5017, a support arm device 5027 that supports the endoscope 5001, and a cart 5037 on which various devices for endoscopic surgery are mounted.

In endoscopic surgery, instead of cutting the abdominal wall and opening the abdomen, multiple punctures using cylindrical drilling instruments called trocars 5025a-5025d are inserted into the abdominal wall. The tube 5003 of the endoscope 5001 and other surgical instruments 5017 are then inserted into the body cavity of the patient 5071 through the trocars 5025a-5025d. In the illustrated example, the other surgical instruments 5017 inserted into the body cavity of the patient 5071 include an insufflation tube 5019, an energy treatment instrument 5021, and forceps 5023. The energy treatment instrument 5021 is a treatment instrument that uses high-frequency current or ultrasonic vibration to incise and dissect tissue, seal blood vessels, and perform other operations. However, the illustrated surgical instrument 5017 is merely an example, and various surgical instruments commonly used in endoscopic surgery, such as a surgeon or retractor, may be used as the surgical instrument 5017.

An image of the surgical site inside the body cavity of the patient 5071, captured by the endoscope 5001, is displayed on the display device 5041. While viewing the image of the surgical site displayed on the display device 5041 in real time, the surgeon 5067 performs treatment such as resecting the affected area using the energy treatment tool 5021 and forceps 5023. Although not shown in the figure, the insufflation tube 5019, energy treatment tool 5021, and forceps 5023 are supported by the surgeon 5067 or an assistant during surgery.

(Support arm device)
The support arm device 5027 includes an arm portion 5031 extending from a base portion 5029. In the example shown, the arm portion 5031 is composed of joints 5033a, 5033b, and 5033c and links 5035a and 5035b, and is driven under control of an arm control device 5045. The arm portion 5031 supports the endoscope 5001, and controls its position and orientation. This allows the endoscope 5001 to be stably fixed in position.

(Endoscopy)
The endoscope 5001 is composed of a lens barrel 5003, a region of a predetermined length from the tip of which is inserted into a body cavity of a patient 5071, and a camera head 5005 connected to the base end of the lens barrel 5003. In the example shown in the figure, the endoscope 5001 is configured as a so-called rigid lens barrel having a rigid lens barrel 5003, but the endoscope 5001 may also be configured as a so-called flexible lens barrel having a flexible lens barrel 5003.

An opening into which an objective lens is fitted is provided at the tip of the tube 5003. A light source device 5043 is connected to the endoscope 5001, and light generated by the light source device 5043 is guided to the tip of the tube by a light guide extending inside the tube 5003, and is then irradiated via the objective lens towards the object to be observed inside the body cavity of the patient 5071. The endoscope 5001 may be a direct-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

The camera head 5005 contains an optical system and an image sensor, and the optical system focuses reflected light (observation light) from the object being observed onto the image sensor. The image sensor photoelectrically converts the observation light to generate an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. This image signal is sent to the camera control unit (CCU) 5039 as RAW data. The camera head 5005 is also equipped with a function for adjusting the magnification and focal length by appropriately driving the optical system.

Note that, for example, to accommodate stereoscopic vision (3D display), the camera head 5005 may be provided with multiple image sensors. In this case, multiple relay optical systems are provided inside the lens barrel 5003 to guide observation light to each of the multiple image sensors.

(Various devices mounted on the cart)
The CCU 5039 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and comprehensively controls the operations of the endoscope 5001 and the display device 5041. Specifically, the CCU 5039 performs various image processing, such as development processing (demosaic processing), on the image signal received from the camera head 5005 in order to display an image based on the image signal. The CCU 5039 provides the image signal after the image processing to the display device 5041. The CCU 5039 also transmits a control signal to the camera head 5005 to control its drive. The control signal may include information regarding imaging conditions, such as magnification and focal length.

Under the control of the CCU 5039, the display device 5041 displays an image based on an image signal that has been image processed by the CCU 5039. If the endoscope 5001 is compatible with high-resolution imaging, such as 4K (3840 horizontal pixels x 2160 vertical pixels) or 8K (7680 horizontal pixels x 4320 vertical pixels), and/or is compatible with 3D display, the display device 5041 may be capable of high-resolution display and/or 3D display, respectively. If the endoscope is compatible with high-resolution imaging, such as 4K or 8K, a display device 5041 with a size of 55 inches or larger can be used to achieve a more immersive experience. Furthermore, multiple display devices 5041 with different resolutions and sizes may be provided depending on the application.

The light source device 5043 is composed of a light source such as an LED (light emitting diode) and supplies illumination light to the endoscope 5001 when photographing the surgical site.

The arm control device 5045 is configured with a processor such as a CPU, and operates according to a predetermined program to control the drive of the arm portion 5031 of the support arm device 5027 according to a predetermined control method.

The input device 5047 is an input interface for the endoscopic surgery system 5000. The user can input various information and instructions to the endoscopic surgery system 5000 via the input device 5047. For example, the user inputs various information related to the surgery, such as the patient's physical information and information about the surgical procedure, via the input device 5047. In addition, for example, the user can input via the input device 5047 instructions to drive the arm unit 5031, instructions to change the imaging conditions (type of irradiation light, magnification, focal length, etc.) of the endoscope 5001, instructions to drive the energy treatment tool 5021, etc.

The type of input device 5047 is not limited, and the input device 5047 may be any known input device. Examples of the input device 5047 that may be used include a mouse, keyboard, touch panel, switch, foot switch 5057, and/or lever. When a touch panel is used as the input device 5047, the touch panel may be provided on the display surface of the display device 5041.

Alternatively, the input device 5047 may be a device worn by the user, such as a glasses-type wearable device or an HMD (Head Mounted Display), and various inputs are made in response to the user's gestures and line of sight detected by these devices. The input device 5047 may also include a camera capable of detecting the user's movements, and various inputs are made in response to the user's gestures and line of sight detected from the image captured by the camera. The input device 5047 may also include a microphone capable of picking up the user's voice, and various inputs are made via voice via the microphone. In this way, the input device 5047 is configured to be able to input various types of information contactlessly, thereby enabling a user (e.g., the surgeon 5067) in a particularly clean area to operate equipment in an unclean area in a contactless manner. Furthermore, the user can operate equipment without removing their hands from the surgical tools they are holding, improving user convenience.

The treatment tool control device 5049 controls the operation of the energy treatment tool 5021 for cauterizing tissue, incising, sealing blood vessels, etc. The insufflation device 5051 sends gas into the body cavity of the patient 5071 via the insufflation tube 5019 to inflate the body cavity in order to ensure a clear field of view for the endoscope 5001 and to ensure working space for the surgeon. The recorder 5053 is a device capable of recording various types of information related to the surgery. The printer 5055 is a device capable of printing various types of information related to the surgery in various formats, such as text, images, or graphs.

Below, we will explain in more detail the particularly distinctive features of the endoscopic surgery system 5000.

(Support arm device)
The support arm device 5027 includes a base 5029 serving as a base and an arm 5031 extending from the base 5029. In the illustrated example, the arm 5031 is composed of multiple joints 5033a, 5033b, and 5033c and multiple links 5035a and 5035b connected by the joint 5033b. However, for simplicity, FIG. 48 illustrates a simplified configuration of the arm 5031. In practice, the shapes, number, and arrangement of the joints 5033a to 5033c and the links 5035a and 5035b, as well as the directions of the rotation axes of the joints 5033a to 5033c, can be appropriately set so that the arm 5031 has the desired degrees of freedom. For example, the arm 5031 can be preferably configured to have six or more degrees of freedom. This allows the endoscope 5001 to be moved freely within the movable range of the arm portion 5031, making it possible to insert the telescope tube 5003 of the endoscope 5001 into the body cavity of the patient 5071 from the desired direction.

Actuators are provided in the joints 5033a to 5033c, and the joints 5033a to 5033c are configured to rotate around a predetermined rotation axis when driven by the actuators. The drive of the actuators is controlled by the arm control device 5045, which controls the rotation angle of each joint 5033a to 5033c and controls the drive of the arm 5031. This makes it possible to control the position and attitude of the endoscope 5001. In this case, the arm control device 5045 can control the drive of the arm 5031 using various known control methods, such as force control or position control.

For example, the surgeon 5067 may perform appropriate operational input via the input device 5047 (including the foot switch 5057), which may then cause the arm control device 5045 to appropriately control the drive of the arm unit 5031 in accordance with the operational input, thereby controlling the position and posture of the endoscope 5001. Through this control, the endoscope 5001 at the tip of the arm unit 5031 can be moved from any position to any other position, and then fixedly supported in that position. The arm unit 5031 may also be operated in a so-called master-slave manner. In this case, the arm unit 5031 can be remotely controlled by the user via the input device 5047 installed in a location away from the operating room.

Furthermore, when force control is applied, the arm control device 5045 may perform so-called power assist control, in which the actuators of the joints 5033a to 5033c are driven so that the arm unit 5031 receives an external force from the user and moves smoothly in accordance with that external force. This allows the user to move the arm unit 5031 with a relatively light force when moving the arm unit 5031 while directly touching it. This makes it possible to move the endoscope 5001 more intuitively and with simpler operations, improving user convenience.

In general, during endoscopic surgery, the endoscope 5001 is supported by a doctor called a scopist. By using the support arm device 5027, the position of the endoscope 5001 can be fixed more reliably without manual intervention, enabling stable images of the surgical site to be obtained and enabling the surgery to be carried out smoothly.

Note that the arm control device 5045 does not necessarily have to be provided on the cart 5037. Furthermore, the arm control device 5045 does not necessarily have to be a single device. For example, an arm control device 5045 may be provided on each of the joints 5033a to 5033c of the arm section 5031 of the support arm device 5027, and drive control of the arm section 5031 may be achieved by multiple arm control devices 5045 working together.

(Light source device)
The light source device 5043 supplies illumination light to the endoscope 5001 when photographing the surgical site. The light source device 5043 is composed of a white light source, such as an LED, a laser light source, or a combination of these. In this case, if the white light source is composed of a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, allowing the light source device 5043 to adjust the white balance of the captured image. In this case, it is also possible to time-share images corresponding to each RGB by irradiating the object of observation with laser light from each RGB laser light source and controlling the drive of the image sensor of the camera head 5005 in synchronization with the irradiation timing. This method allows color images to be obtained without providing a color filter to the image sensor.

The light source device 5043 may also be controlled to change the intensity of the light it outputs at predetermined time intervals. The image sensor of the camera head 5005 is controlled to acquire images in a time-division manner in synchronization with the timing of the change in light intensity, and these images are then combined to generate a high dynamic range image free of so-called blocked-up shadows and blown-out highlights.

The light source device 5043 may also be configured to provide light in a predetermined wavelength band compatible with special light observation. Special light observation, for example, utilizes the wavelength dependence of light absorption in body tissue to irradiate light with a narrower band than the light irradiated during normal observation (i.e., white light), thereby capturing high-contrast images of specific tissue, such as blood vessels on the surface of the mucosa, in what is known as narrow-band imaging. Alternatively, special light observation may involve fluorescence observation, in which images are obtained using fluorescence generated by irradiating excitation light. Fluorescence observation may involve irradiating excitation light onto body tissue and observing the fluorescence from the tissue (autofluorescence observation), or irradiating the tissue with excitation light corresponding to the fluorescent wavelength of a reagent such as indocyanine green (ICG) to obtain a fluorescent image. The light source device 5043 may be configured to provide narrow-band light and/or excitation light compatible with such special light observation.

(Camera head and CCU)
The functions of the camera head 5005 and the CCU 5039 of the endoscope 5001 will be described in more detail with reference to Fig. 49. Fig. 49 is a block diagram showing an example of the functional configuration of the camera head 5005 and the CCU 5039 shown in Fig. 48.

Referring to Figure 49, the camera head 5005 has, as its functions, a lens unit 5007, an imaging unit 5009, a drive unit 5011, a communication unit 5013, and a camera head control unit 5015. The CCU 5039 also has, as its functions, a communication unit 5059, an image processing unit 5061, and a control unit 5063. The camera head 5005 and CCU 5039 are connected via a transmission cable 5065 to enable bidirectional communication.

First, the functional configuration of the camera head 5005 will be described. The lens unit 5007 is an optical system provided at the connection point with the lens barrel 5003. Observation light taken in from the tip of the lens barrel 5003 is guided to the camera head 5005 and enters the lens unit 5007. The lens unit 5007 is composed of a combination of multiple lenses, including a zoom lens and a focus lens. The optical characteristics of the lens unit 5007 are adjusted so that the observation light is focused on the light receiving surface of the image sensor of the imaging section 5009. In addition, the zoom lens and focus lens are configured so that their positions on the optical axis can be moved to adjust the magnification and focus of the captured image.

The imaging unit 5009 is composed of an imaging element and is arranged after the lens unit 5007. Observation light that passes through the lens unit 5007 is focused on the light-receiving surface of the imaging element, and an image signal corresponding to the observed image is generated by photoelectric conversion. The image signal generated by the imaging unit 5009 is provided to the communication unit 5013.

The imaging element constituting the imaging unit 5009 is, for example, a CMOS (Complementary Metal Oxide Semiconductor) type image sensor with a Bayer array capable of color imaging. The imaging element may also be capable of capturing high-resolution images, for example, 4K or higher. Obtaining high-resolution images of the surgical site allows the surgeon 5067 to grasp the state of the surgical site in more detail, enabling the surgery to proceed more smoothly.

The imaging element constituting the imaging unit 5009 is configured to have a pair of imaging elements for acquiring image signals for the right eye and left eye, respectively, corresponding to 3D display. 3D display allows the surgeon 5067 to more accurately grasp the depth of the biological tissue at the surgical site. Note that if the imaging unit 5009 is configured as a multi-plate type, multiple lens units 5007 are also provided corresponding to each imaging element.

Furthermore, the imaging unit 5009 does not necessarily have to be provided in the camera head 5005. For example, the imaging unit 5009 may be provided inside the lens barrel 5003, immediately after the objective lens.

The drive unit 5011 is composed of an actuator, and under the control of the camera head control unit 5015, moves the zoom lens and focus lens of the lens unit 5007 a predetermined distance along the optical axis. This allows the magnification and focus of the image captured by the imaging unit 5009 to be adjusted appropriately.

The communication unit 5013 is composed of a communication device for transmitting and receiving various information to and from the CCU 5039. The communication unit 5013 transmits image signals obtained from the imaging unit 5009 as RAW data to the CCU 5039 via the transmission cable 5065. At this time, in order to display the captured images of the surgical site with low latency, it is preferable that the image signals be transmitted via optical communication. During surgery, the surgeon 5067 performs the surgery while observing the condition of the affected area using the captured images, so for a safer and more reliable surgery, it is necessary that moving images of the surgical site be displayed as real-time as possible. When optical communication is used, the communication unit 5013 is provided with a photoelectric conversion module that converts electrical signals into optical signals. The image signals are converted into optical signals by the photoelectric conversion module and then transmitted to the CCU 5039 via the transmission cable 5065.

The communication unit 5013 also receives control signals from the CCU 5039 for controlling the operation of the camera head 5005. These control signals include information related to the imaging conditions, such as information specifying the frame rate of the captured image, information specifying the exposure value during imaging, and/or information specifying the magnification and focus of the captured image. The communication unit 5013 provides the received control signals to the camera head control unit 5015. Note that the control signals from the CCU 5039 may also be transmitted by optical communication. In this case, the communication unit 5013 is provided with a photoelectric conversion module that converts optical signals into electrical signals, and the control signals are converted into electrical signals by the photoelectric conversion module before being provided to the camera head control unit 5015.

The above-mentioned imaging conditions, such as frame rate, exposure value, magnification, and focus, are automatically set by the control unit 5063 of the CCU 5039 based on the acquired image signal. In other words, the endoscope 5001 is equipped with so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function.

The camera head control unit 5015 controls the driving of the camera head 5005 based on control signals received from the CCU 5039 via the communication unit 5013. For example, the camera head control unit 5015 controls the driving of the image sensor of the imaging unit 5009 based on information specifying the frame rate of the captured image and/or information specifying the exposure during image capture. Furthermore, for example, the camera head control unit 5015 appropriately moves the zoom lens and focus lens of the lens unit 5007 via the drive unit 5011 based on information specifying the magnification and focus of the captured image. The camera head control unit 5015 may further have a function for storing information for identifying the lens barrel 5003 and the camera head 5005.

In addition, by arranging components such as the lens unit 5007 and imaging unit 5009 in a sealed structure that is highly airtight and waterproof, the camera head 5005 can be made resistant to autoclave sterilization.

Next, the functional configuration of the CCU 5039 will be described. The communication unit 5059 is composed of a communication device for transmitting and receiving various information to and from the camera head 5005. The communication unit 5059 receives an image signal transmitted from the camera head 5005 via the transmission cable 5065. At this time, as described above, the image signal can be preferably transmitted by optical communication. In this case, to support optical communication, the communication unit 5059 is provided with an optoelectric conversion module that converts optical signals into electrical signals. The communication unit 5059 provides the image signal converted into an electrical signal to the image processing unit 5061.

The communication unit 5059 also transmits a control signal to the camera head 5005 for controlling the operation of the camera head 5005. This control signal may also be transmitted by optical communication.

The image processing unit 5061 performs various types of image processing on the image signal, which is RAW data transmitted from the camera head 5005. This image processing includes various well-known signal processing such as development processing, high-quality image processing (band enhancement processing, super-resolution processing, NR (Noise Reduction) processing, and/or image stabilization processing, etc.), and/or enlargement processing (electronic zoom processing). The image processing unit 5061 also performs detection processing on the image signal to perform AE, AF, and AWB.

The image processing unit 5061 is configured with a processor such as a CPU or GPU, and the processor operates in accordance with a predetermined program to perform the image processing and detection processing described above. If the image processing unit 5061 is configured with multiple GPUs, the image processing unit 5061 divides the information related to the image signal appropriately and performs image processing in parallel using these multiple GPUs.

The control unit 5063 performs various controls related to the imaging of the surgical site by the endoscope 5001 and the display of the captured images. For example, the control unit 5063 generates a control signal for controlling the operation of the camera head 5005. At this time, if the imaging conditions have been input by the user, the control unit 5063 generates a control signal based on the user's input. Alternatively, if the endoscope 5001 is equipped with an AE function, an AF function, and an AWB function, the control unit 5063 appropriately calculates the optimal exposure value, focal length, and white balance according to the results of the detection processing by the image processing unit 5061, and generates a control signal.

The control unit 5063 also displays an image of the surgical site on the display device 5041 based on the image signal that has been image processed by the image processing unit 5061. At this time, the control unit 5063 recognizes various objects within the surgical site image using various image recognition technologies. For example, the control unit 5063 can recognize surgical tools such as forceps, specific biological parts, bleeding, mist generated when using the energy treatment tool 5021, and the like by detecting the shape and color of the edges of objects included in the surgical site image. When the control unit 5063 displays the image of the surgical site on the display device 5041, it uses the recognition results to superimpose various surgical support information onto the image of the surgical site. By superimposing the surgical support information and presenting it to the surgeon 5067, the surgery can be carried out more safely and reliably.

The transmission cable 5065 connecting the camera head 5005 and the CCU 5039 is an electrical signal cable for electrical signal communication, an optical fiber for optical communication, or a composite cable of these.

In the illustrated example, communication is performed wired using a transmission cable 5065, but communication between the camera head 5005 and the CCU 5039 may also be performed wirelessly. If communication between the two is performed wirelessly, there is no need to lay the transmission cable 5065 within the operating room, which can eliminate the situation where the transmission cable 5065 interferes with the movement of medical staff within the operating room.

The above describes an example of an endoscopic surgery system 5000 to which the technology disclosed herein can be applied. Note that while the endoscopic surgery system 5000 has been described here as an example, systems to which the technology disclosed herein can be applied are not limited to this example. For example, the technology disclosed herein may be applied to flexible endoscope systems for inspection or microsurgery systems.

The technology disclosed herein can be suitably applied to the camera head 5005 of the configurations described above. In particular, the optical system disclosed herein can be suitably applied to the lens unit 5007 of the camera head 5005.

6. Other embodiments
The technology according to the present disclosure is not limited to the above-described embodiment and examples, and various modifications are possible.

For example, the shapes and numerical values of each part shown in the above examples are merely examples of specific embodiments for implementing this technology, and should not be interpreted as limiting the technical scope of this technology.

Furthermore, in the above embodiment and example, a configuration consisting essentially of three lens groups has been described, but the configuration may also include an additional lens that has essentially no refractive power.

For example, the present technology can be configured as follows.
According to the present technology having the following configuration, the entire lens group is configured with three lens groups, and the configuration of each lens group is optimized, making it possible to realize an optical system and an imaging device that are lightweight, easy to handle, and have high optical performance across the entire screen.

[1]
From the object side to the image plane side,
a first lens group having positive refractive power as a whole, the first lens group being fixed relative to an image plane during focusing;
a second lens group that has positive or negative refractive power as a whole and performs focusing from infinity to a close distance by moving the whole group in the optical axis direction;
a third lens group divided into, in order from the object side toward the image plane side, a 3a group, a 3b group, and a 3c group, the 3b group being adapted to correct image blur by moving in a direction approximately perpendicular to the optical axis, the group as a whole having negative or positive refractive power, and the group as a whole being fixed relative to the image plane during focusing;
An optical system that satisfies the following condition:
L/f<1...(1)
D_g1max/f>0.23...(2)
D_3bImg/f<0.24...(3)
however,
L: distance from the surface of the first lens group closest to the object to the image plane; f: focal length of the entire system when focused at infinity; D_g1max: maximum air gap on the optical axis within the first lens group; D_3bImg: distance from the surface of the 3b group closest to the object to the image plane.
[2]
The optical system according to the above [1], wherein the first lens group has at least one positive lens that satisfies the following conditional expressions (4) and (5):
νd_1p>90...(4)
θgF_1p-(-0.001801*νd_1p+0.648262)>0.04...(5)
however,
νd_1p: Abbe number of the positive lens in the first lens group for the d-line, and θgF_1p: partial dispersion ratio of the positive lens in the first lens group for the g-line and the F-line.
[3]
The optical system according to the above [1] or [2], wherein the 3c group includes at least one negative lens that satisfies the following conditional expression (6):
θgF_3cn-(-0.001801*νd_3cn+0.648262)>0.008...(6)
however,
θgF_3cn: partial dispersion ratio between the g line and the F line of the negative lens in the 3c group. νd_3cn: Abbe number for the d line of the negative lens in the 3c group.
[4]
The optical system according to any one of [1] to [3] above, wherein the 3c group includes at least one negative lens that satisfies the following conditional expression (7):
νd_3cn<31...(7)
however,
νd_3cn: Abbe number for the d-line of the negative lens in the 3c group.
[5]
The optical system according to any one of [1] to [4] above, wherein the 3c group includes at least one negative lens that satisfies the following conditional expression (8):
0<|f3cn/f|<0.15...(8)
however,
f3cn: focal length of the negative lens in the 3c group; f: focal length of the entire system when focused at infinity.
[6]
The optical system according to the above [1] or [2], wherein the 3c group includes at least one negative lens that satisfies any one of the following conditional expressions (6), (7), and (8) and conditional expression (9):
θgF_3cn-(-0.001801*νd_3cn+0.648262)>0.008...(6)
νd_3cn<31...(7)
0<|f3cn/f|<0.15...(8)
D_3cnImg/f<0.15...(9)
however,
θgF_3cn: partial dispersion ratio between the g line and the F line of the negative lens in the 3c group νd_3cn: Abbe number for the d line of the negative lens in the 3c group f3cn: focal length of the negative lens in the 3c group f: focal length of the entire system when focused at infinity D_3cnImg: distance between the vertex of the object-side surface of the negative lens in the 3c group and the image plane.
[7]
The optical system according to any one of [1] to [6] above, wherein the first lens group has at least one negative lens that satisfies the following conditional expressions (10) and (11):
νd_1n<35...(10)
θgF_1n-(-0.001801*νd_1n+0.648262)<0.010...(11)
however,
νd_1n: Abbe number for d-line of the negative lens in the first lens group, and θgF_1n: partial dispersion ratio for g-line and F-line of the negative lens in the first lens group.
[8]
The optical system according to any one of the above [1] to [7], which satisfies the following conditional expression:
0.05<|f3c/f|<0.3...(12)
however,
f3c: focal length of the 3c group; f: focal length of the entire system when focused at infinity.
[9]
The optical system according to any one of [1] to [8] above, wherein the second lens group is composed of a cemented lens or a single lens.
[10]
The optical system according to any one of [1] to [9] above, wherein the second lens group has a positive refractive power as a whole, and the third lens group has a negative refractive power as a whole.
[11]
The optical system according to any one of [1] to [9] above, wherein the second lens group has a negative refractive power as a whole, and the third lens group has a positive refractive power as a whole.
[12]
The optical system according to any one of [1] to [9] above, wherein the second lens group has a negative refractive power as a whole, and the third lens group has a negative refractive power as a whole.
[13]
an optical system; and an imaging element that outputs an imaging signal corresponding to an optical image formed by the optical system;
The optical system comprises:
From the object side to the image plane side,
a first lens group having positive refractive power as a whole, the first lens group being fixed relative to an image plane during focusing;
a second lens group that has positive or negative refractive power as a whole and performs focusing from infinity to a close distance by moving the whole group in the optical axis direction;
a third lens group divided into, in order from the object side toward the image plane side, a 3a group, a 3b group, and a 3c group, the 3b group being adapted to correct image blur by moving in a direction approximately perpendicular to the optical axis, the group as a whole having negative or positive refractive power, and the group as a whole being fixed relative to the image plane during focusing;
An imaging device that satisfies the following conditional expression:
L/f<1...(1)
D_g1max/f>0.23...(2)
D_3bImg/f<0.24...(3)
however,
L: distance from the surface of the first lens group closest to the object to the image plane; f: focal length of the entire system when focused at infinity; D_g1max: maximum air gap on the optical axis within the first lens group; D_3bImg: distance from the surface of the 3b group closest to the object to the image plane.
[14]
The optical system according to any one of [1] to [12] above, further comprising a lens having substantially no refractive power.
[15]
The imaging device according to [13] above, wherein the optical system further comprises a lens having substantially no refractive power.

This application claims priority based on Japanese Patent Application No. 2019-104612, filed on June 4, 2019, with the Japan Patent Office, the entire contents of which are incorporated herein by reference.

It is understood that those skilled in the art will be able to conceive of various modifications, combinations, subcombinations, and variations depending on design requirements and other factors, and that these are within the scope of the appended claims and their equivalents.

Claims (15)

From the object side to the image plane side,
a first lens group having positive refractive power as a whole, the first lens group being fixed relative to an image plane during focusing;
a second lens group that has positive refractive power as a whole and performs focusing from infinity to a close distance by moving the whole group in the optical axis direction;
a third lens group which is divided into, in order from the object side toward the image plane side, a 3a group, a 3b group, and a 3c group, the 3b group being adapted to correct image blur by moving in a direction approximately perpendicular to the optical axis, the group as a whole having negative refractive power, and the group as a whole being fixed relative to the image plane during focusing;
an aperture stop is provided between the 3a group and the 3b group in the third lens group,
The following conditional expressions (1) to (3) are satisfied:
The optical system includes at least one negative lens element that satisfies the following conditional expression (6):
L/f<1...(1)
D_g1max/f>0.23...(2)
D_3bImg/f<0.24...(3)
θgF_3cn-(-0.001801*νd_3cn+0.648262)>0.008...(6)
however,
L: distance from the surface of the first lens group closest to the object to the image plane f: focal length of the entire system when focused at infinity D_g1max: maximum air gap on the optical axis within the first lens group D_3bImg: distance from the surface of the 3b group closest to the object to the image plane θgF_3cn: partial dispersion ratio between the g line and the F line of the negative lens in the 3c group νd_3cn: Abbe number for the d line of the negative lens in the 3c group From the object side to the image plane side,
a first lens group having positive refractive power as a whole, the first lens group being fixed relative to an image plane during focusing;
a second lens group that has negative refractive power as a whole and performs focusing from infinity to a close distance by moving the whole group in the optical axis direction;
a third lens group divided into, in order from the object side toward the image plane side, a 3a group, a 3b group, and a 3c group, the 3b group being adapted to correct image blur by moving in a direction approximately perpendicular to the optical axis, the group as a whole having positive refractive power, and the group as a whole being fixed relative to the image plane during focusing;
an aperture stop is provided between the 3a group and the 3b group in the third lens group,
The following conditional expressions (1) to (3) are satisfied:
The optical system includes at least one negative lens element that satisfies the following conditional expression (6):
L/f<1...(1)
D_g1max/f>0.23...(2)
D_3bImg/f<0.24...(3)
θgF_3cn-(-0.001801*νd_3cn+0.648262)>0.008...(6)
however,
L: distance from the surface of the first lens group closest to the object to the image plane f: focal length of the entire system when focused at infinity D_g1max: maximum air gap on the optical axis within the first lens group D_3bImg: distance from the surface of the 3b group closest to the object to the image plane θgF_3cn: partial dispersion ratio between the g line and the F line of the negative lens in the 3c group νd_3cn: Abbe number for the d line of the negative lens in the 3c group 3. The optical system according to claim 1, wherein the first lens group has at least one positive lens that satisfies the following conditional expressions (4) and (5):
νd_1p>90...(4)
θgF_1p-(-0.001801*νd_1p+0.648262)>0.04...(5)
however,
νd_1p: Abbe number of the positive lens in the first lens group for the d-line, and θgF_1p: partial dispersion ratio of the positive lens in the first lens group for the g-line and the F-line. The optical system according to claim 1 , wherein the 3c group includes at least one negative lens that satisfies the following conditional expression (7):
νd_3cn<31...(7)
however,
νd_3cn: Abbe number for the d-line of the negative lens in the 3c group. The optical system according to claim 1 , wherein the 3c group includes at least one negative lens that satisfies the following conditional expression (8):
0<|f3cn/f|<0.15...(8)
however,
f3cn: focal length of the negative lens in the 3c group; f: focal length of the entire system when focused at infinity. 3. The optical system according to claim 1, wherein the 3c group includes at least one negative lens that satisfies either conditional expression (7) or (8) below and conditional expression (9).
νd_3cn<31...(7)
0<|f3cn/f|<0.15...(8)
D_3cnImg/f<0.15...(9)
however,
νd_3cn: Abbe number for the d-line of the negative lens in the 3c group, f3cn: focal length of the negative lens in the 3c group, f: focal length of the entire system when focused at infinity, and D_3cnImg: distance between the vertex of the object-side surface of the negative lens in the 3c group and the image plane. 3. The optical system according to claim 1, wherein the first lens group has at least one negative lens that satisfies the following conditional expressions (10) and (11):
νd_1n<35...(10)
θgF_1n-(-0.001801*νd_1n+0.648262)<0.010...(11)
however,
νd_1n: Abbe number for d-line of the negative lens in the first lens group, and θgF_1n: partial dispersion ratio for g-line and F-line of the negative lens in the first lens group. The optical system according to claim 1 or 2, which satisfies the following conditional expression:
0.05<|f3c/f|<0.3...(12)
however,
f3c: focal length of the 3c group; f: focal length of the entire system when focused at infinity. The optical system according to claim 1 , wherein the second lens group is made up of a cemented lens or a single lens. The optical system according to claim 2 , wherein the second lens group is made of a cemented lens. The optical system according to claim 1 or 2, wherein, during image blur correction, only the 3b group moves in a direction substantially perpendicular to the optical axis. an optical system; and an imaging element that outputs an imaging signal corresponding to an optical image formed by the optical system;
The optical system comprises:
From the object side to the image plane side,
a first lens group having positive refractive power as a whole, the first lens group being fixed relative to an image plane during focusing;
a second lens group that has positive refractive power as a whole and performs focusing from infinity to a close distance by moving the whole group in the optical axis direction;
a third lens group which is divided into, in order from the object side toward the image plane side, a 3a group, a 3b group, and a 3c group, the 3b group being adapted to correct image blur by moving in a direction approximately perpendicular to the optical axis, the group as a whole having negative refractive power, and the group as a whole being fixed relative to the image plane during focusing;
an aperture stop is provided between the 3a group and the 3b group in the third lens group,
The following conditional expressions (1) to (3) are satisfied:
The imaging device, wherein the 3c group includes at least one negative lens that satisfies the following conditional expression (6):
L/f<1...(1)
D_g1max/f>0.23...(2)
D_3bImg/f<0.24...(3)
θgF_3cn-(-0.001801*νd_3cn+0.648262)>0.008...(6)
however,
L: distance from the surface of the first lens group closest to the object to the image plane f: focal length of the entire system when focused at infinity D_g1max: maximum air gap on the optical axis within the first lens group D_3bImg: distance from the surface of the 3b group closest to the object to the image plane θgF_3cn: partial dispersion ratio between the g line and the F line of the negative lens in the 3c group νd_3cn: Abbe number for the d line of the negative lens in the 3c group an optical system; and an imaging element that outputs an imaging signal corresponding to an optical image formed by the optical system;
The optical system comprises:
From the object side to the image plane side,
a first lens group having positive refractive power as a whole, the first lens group being fixed relative to an image plane during focusing;
a second lens group that has negative refractive power as a whole and performs focusing from infinity to a close distance by moving the whole group in the optical axis direction;
a third lens group divided into, in order from the object side toward the image plane side, a 3a group, a 3b group, and a 3c group, the 3b group being adapted to correct image blur by moving in a direction approximately perpendicular to the optical axis, the group as a whole having positive refractive power, and the group as a whole being fixed relative to the image plane during focusing;
an aperture stop is provided between the 3a group and the 3b group in the third lens group,
The following conditional expressions (1) to (3) are satisfied:
The imaging device, wherein the 3c group includes at least one negative lens that satisfies the following conditional expression (6):
L/f<1...(1)
D_g1max/f>0.23...(2)
D_3bImg/f<0.24...(3)
θgF_3cn-(-0.001801*νd_3cn+0.648262)>0.008...(6)
however,
L: distance from the surface of the first lens group closest to the object to the image plane f: focal length of the entire system when focused at infinity D_g1max: maximum air gap on the optical axis within the first lens group D_3bImg: distance from the surface of the 3b group closest to the object to the image plane θgF_3cn: partial dispersion ratio between the g line and the F line of the negative lens in the 3c group νd_3cn: Abbe number for the d line of the negative lens in the 3c group The optical system according to claim 1 , further comprising a lens having substantially no refractive power. The imaging device according to claim 12 or 13 , wherein the optical system further comprises a lens having substantially no refractive power.