JP7767786B2 - Zoom lens and imaging device - Google Patents

Description

This disclosure relates to a zoom lens and an imaging device.

Photographic optical systems used in imaging devices (cameras) require optical systems with a variety of focal lengths and apertures depending on the application. For example, telephoto zoom lenses that can capture distant subjects at a desired angle of view require high image quality, be compact and lightweight, have a high zoom ratio, and be capable of quick focusing. A known zoom lens that meets these requirements is a positive-lead type, in which a lens group with positive refractive power is positioned closest to the object (see, for example, Patent Documents 1 and 2).

Japanese Patent Application Laid-Open No. 2020-106778 Japanese Patent Application Laid-Open No. 2020-52338

To achieve high image quality in telephoto zoom lenses, it is important to correct various aberrations that occur during zooming, such as axial chromatic aberration, lateral chromatic aberration, spherical aberration, and field curvature, but suppressing fluctuations requires a large number of lenses. In the zoom lenses described in Patent Documents 1 and 2, the refractive power of the positive lens group that moves during magnification variation is very strong, which increases the lens weight and number of lenses, making them less than optimal for a lightweight zoom lens configuration.

It is desirable to provide a zoom lens and imaging device that is lightweight yet capable of effectively correcting various aberrations.

A first zoom lens according to an embodiment of the present disclosure comprises, in order from the object side to the image plane side, a first fixed lens group that remains fixed during zooming, a variable magnification lens group that is arranged closer to the object than the aperture stop and has a plurality of lens groups including a positive lens group and a negative lens group that move along different trajectories during zooming, a second fixed lens group that has positive refractive power and remains fixed during zooming, and a first focus lens group that is arranged adjacent to the second fixed lens group on the image plane side and moves during zooming and focusing, the plurality of lens groups in the variable magnification lens group having three lens groups, the lens group with the largest absolute value of refractive power among the plurality of lens groups in the variable magnification lens group being composed of three or fewer lenses, and satisfying the following conditional expression:
0.05≦ffix/fzp<0.67...(1)
however,
fzp: focal length of the lens group having the greatest positive refractive power among the plurality of lens groups in the variable magnification lens group; ffix: focal length of the second fixed lens group.

A second zoom lens according to an embodiment of the present disclosure comprises, in order from the object side to the image plane side, a first fixed lens group that remains fixed during zooming, a variable magnification lens group that is arranged closer to the object than the aperture stop and has a plurality of lens groups including a positive lens group and a negative lens group that move along different trajectories during zooming, a second fixed lens group that has positive refractive power and remains fixed during zooming, a first focus lens group that is arranged adjacent to the second fixed lens group on the image plane side and moves during zooming and focusing , and the second focus lens group that moves together with the first focus lens group during focusing , wherein the lens group with the largest absolute value of refractive power among the plurality of lens groups in the variable magnification lens group is composed of three or fewer lenses , and satisfies the following conditional expression:
0.05≦ffix/fzp<0.67...(1)
0.5<|ff1/ff2|<3.0...(3)
however,
fzp: focal length of the lens group having the greatest positive refractive power among the multiple lens groups in the magnification-varying lens group ffix: focal length of the second fixed lens group
ff1: focal length of the first focus lens group
ff2: focal length of the second focus lens group
Let's say.

A first imaging device according to one embodiment of the present disclosure includes a zoom lens and an imaging element that outputs an imaging signal corresponding to an optical image formed by the zoom lens, and the zoom lens is configured by the first zoom lens according to the embodiment of the present disclosure.

A second imaging device according to one embodiment of the present disclosure includes a zoom lens and an imaging element that outputs an imaging signal corresponding to an optical image formed by the zoom lens, and the zoom lens is configured by the second zoom lens according to the embodiment of the present disclosure.

In the first or second zoom lens or the first or second image pickup device according to an embodiment of the present disclosure, the configuration of each lens group is optimized to enable excellent correction of various aberrations while remaining lightweight.

1 is a lens cross-sectional view showing a first configuration example (Example 1) of a zoom lens according to an embodiment of the present disclosure. 4A and 4B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 1 at the wide-angle end and when focused on infinity. 4A and 4B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 1 when the zoom lens is positioned at an intermediate point and focused at infinity. 4A and 4B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 1 at the telephoto end when focused on infinity. 4A and 4B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 1 at the wide-angle end when focusing on a close distance. 5A and 5B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 1 at an intermediate position and when focusing on a close distance. 4A and 4B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 1 at the telephoto end when focusing on a close object. 4A and 4B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 1 at the wide-angle end and when focused on infinity. 5A and 5B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 1 when the zoom lens is positioned at an intermediate point and focused on infinity. 4A and 4B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 1 at the telephoto end and when focused on infinity. 4A and 4B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 1 at the wide-angle end when focusing on a close distance. 5A and 5B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 1 at an intermediate position and when focusing on a close distance. 4A and 4B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 1 at the telephoto end when focusing on a close object. FIG. 1 is a lens cross-sectional view showing a second configuration example (Example 2) of a zoom lens according to an embodiment. 10A and 10B are aberration diagrams illustrating longitudinal aberrations at the wide-angle end of the zoom lens according to Example 2 when focused on infinity. 10A and 10B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 2 when the zoom lens is positioned at an intermediate point and focused on infinity. 10A and 10B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 2 at the telephoto end when focused on infinity. 10A and 10B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 2 at the wide-angle end when focusing on a close distance. 10A and 10B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 2 when the zoom lens is positioned at an intermediate position and focused on a close distance. 10A and 10B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 2 at the telephoto end when focusing on a close object. 10A and 10B are aberration diagrams illustrating lateral aberrations at the wide-angle end of the zoom lens according to Example 2 when focused on infinity. 10A and 10B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 2 when the zoom lens is positioned at an intermediate point and focused at infinity. 10A and 10B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 2 at the telephoto end when focused on infinity. 10A and 10B are aberration diagrams illustrating lateral aberrations at the wide-angle end of the zoom lens according to Example 2 when focusing on a close distance. 10A and 10B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 2 when the zoom lens is positioned at an intermediate position and focused on a close distance. 10A and 10B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 2 at the telephoto end when focusing on a close distance. FIG. 10 is a lens cross-sectional view showing a third configuration example (Example 3) of a zoom lens according to an embodiment. 10A and 10B are aberration diagrams illustrating longitudinal aberrations at the wide-angle end of the zoom lens according to Example 3 when focused on infinity. 10A and 10B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 3 when the zoom lens is positioned at an intermediate point and focused on infinity. 10A and 10B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 3 at the telephoto end when focused on infinity. 10A and 10B are aberration diagrams illustrating longitudinal aberrations at the wide-angle end of the zoom lens according to Example 3 when focusing on a close distance. 10A and 10B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 3 when the zoom lens is positioned at an intermediate position and focused on a close distance. 10A and 10B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 3 at the telephoto end when focusing on a close object. 10A and 10B are aberration diagrams illustrating lateral aberrations at the wide-angle end of the zoom lens according to Example 3 when focused on infinity. 10A and 10B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 3 when the zoom lens is positioned at an intermediate point and focused on infinity. 10A and 10B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 3 at the telephoto end when focused on infinity. 10A and 10B are aberration diagrams illustrating lateral aberrations at the wide-angle end of the zoom lens according to Example 3 when focusing on a close distance. 10A and 10B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 3 when the zoom lens is positioned at an intermediate position and focused on a close distance. 10A and 10B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 3 at the telephoto end when focusing on a close distance. FIG. 10 is a lens cross-sectional view showing a fourth configuration example (Example 4) of a zoom lens according to an embodiment. 10A and 10B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 4 at the wide-angle end and when focused on infinity. 10A and 10B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 4 when the zoom lens is positioned at an intermediate point and focused on infinity. 10A and 10B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 4 at the telephoto end when focused on infinity. 10A and 10B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 4 at the wide-angle end when focusing on a close distance. 10A and 10B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 4 when the zoom lens is positioned at an intermediate position and focused on a close distance. 10A and 10B are aberration diagrams illustrating longitudinal aberrations of the zoom lens according to Example 4 at the telephoto end when focusing on a close object. 10A and 10B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 4 at the wide-angle end and when focused on infinity. 10A and 10B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 4 when the zoom lens is positioned at an intermediate point and focused on infinity. 10A and 10B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 4 at the telephoto end when focused on infinity. 10A and 10B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 4 at the wide-angle end when focusing on a close distance. 10A and 10B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 4 when the zoom lens is positioned at an intermediate position and focused on a close distance. 10A and 10B are aberration diagrams illustrating lateral aberrations of the zoom lens according to Example 4 at the telephoto end when focusing on a close object. 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. FIG. 1 is a diagram illustrating an example of a schematic configuration of an endoscope system. A block diagram showing an example of the functional configuration of the camera and CCU shown in Figure 56. FIG. 1 is a diagram illustrating an example of a schematic configuration of a microsurgery system.

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.
1. Basic lens configuration 2. Actions and effects 3. Examples of application to imaging devices 4. Numerical examples of lenses 5. Application examples 6. Other embodiments

<1. Basic lens structure>
FIG. 1 shows a first configuration example of a zoom lens according to an embodiment of the present disclosure, which corresponds to the configuration of Example 1 described below. FIG. 14 shows a second configuration example of a zoom lens according to an embodiment, which corresponds to the configuration of Example 2 described below. FIG. 27 shows a third configuration example of a zoom lens according to an embodiment, which corresponds to the configuration of Example 3 described below. FIG. 40 shows a fourth configuration example of a zoom lens according to an embodiment, which corresponds to the configuration of Example 4 described below.

In Figure 1 and other figures, Z1 indicates the optical axis. An optical element such as a cover glass for protecting the image sensor may be disposed between the zoom lenses 1 to 4 according to the first to fourth configuration examples and the image plane IMG. In addition to the cover glass, various optical filters such as a low-pass filter or an infrared cut filter may also be disposed as optical elements.

The configuration of a zoom lens according to an embodiment of the present disclosure will be described below, corresponding to zoom lenses 1 to 4 according to the configuration examples shown in Figure 1 and elsewhere, as appropriate; however, the technology according to the present disclosure is not limited to the configuration examples shown.

A zoom lens according to one embodiment comprises, in order from the object side to the image plane side, a first fixed lens group that remains fixed during zooming, a zoom lens group that is positioned closer to the object than the aperture stop St, a second fixed lens group that has positive refractive power and remains fixed during zooming, and a first focus lens group.

The variable magnification lens group has multiple lens groups, including a positive lens group and a negative lens group, which move on different trajectories. Of the multiple lens groups in the variable magnification lens group, the lens group with the largest absolute value of refractive power is composed of, for example, three lenses or less. The multiple lens groups in the variable magnification lens group are composed of, for example, three lens groups.

The first focus lens group is positioned adjacent to the second fixed lens group on the image plane side and moves during zooming and focusing. Note that the zoom lens according to one embodiment may further include a second focus lens group.

In Figure 1 and other figures, the upper row shows the lens arrangement when the lens is at the wide-angle end (Wide) and focused at infinity, and the middle row shows the lens arrangement when the lens is at the intermediate position (Mid) and focused at infinity. The lower row shows the lens arrangement when the lens is at the telephoto end (Tele) and focused at infinity. Also, in Figure 1 and other figures, arrows indicate the direction of movement of the first and second focus lens groups when focusing from infinity to a close distance.

In the examples described below, the zoom lenses according to Examples 1 to 4 are composed of a first lens group GR1 to an eighth lens group GR8. In the zoom lenses according to Examples 1 to 4 described below, the first lens group GR1 corresponds to the first fixed lens group described above. The second lens group GR2 to the fourth lens group GR4 correspond to the variable magnification lens group described above. The fifth lens group GR5 corresponds to the second fixed lens group described above. The sixth lens group GR6 corresponds to the first focus lens group described above. The seventh lens group GR7 corresponds to the second focus lens group described above.

In addition, the zoom lens according to one embodiment may further satisfy certain conditional expressions, etc., which will be described later.

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

In a zoom lens according to one embodiment, the configuration of each lens group is optimized to enable excellent correction of various aberrations while being lightweight. This makes it possible to provide a zoom lens that is lightweight yet capable of excellent correction of various aberrations, as well as an imaging device equipped with such a zoom lens.

In a zoom lens according to one embodiment, the variable magnification lens group has a positive lens group and a negative lens group, and the positive lens group and the negative lens group move on different trajectories. This allows for a large change in the combined focal length of the variable magnification lens group, thereby suppressing fluctuations in various aberrations caused by zooming. Furthermore, by configuring the lens group with the largest absolute value of refractive power among the multiple lens groups in the variable magnification lens group to consist of three or fewer lenses, it is possible to suppress the weight increase of the lens group with the largest refractive power, which tends to be heavy. Note that configuring the lens group with the largest absolute value of refractive power to consist of two or fewer lenses is preferable, as this further suppresses weight increase. Note that in the examples described below, in the zoom lens according to Example 1, the fourth lens group GR4 corresponds to the lens group with the largest absolute value of refractive power, and in the zoom lenses according to Examples 2 to 4, the second lens group GR2 corresponds to the lens group with the largest absolute value of refractive power.

In addition, in a zoom lens according to one embodiment, by including a negative lens group and a positive lens group in the variable magnification lens group, it is possible to reduce the number of lenses while controlling the composite principal point position and correcting aberration fluctuations due to zooming. Furthermore, by locating a second fixed lens group with strong positive refractive power on the object side of the first focus lens group, it is possible to reduce the diameter of the first focus lens group.

A zoom lens according to an embodiment may satisfy the following conditional expression (1).
0.05≦ffix/fzp<0.67...(1)
however,
fzp: focal length of the lens group having the greatest positive refractive power among the plurality of lens groups in the variable magnification lens group; ffix: focal length of the second fixed lens group.

Conditional formula (1) establishes an appropriate relationship between the focal length of the second fixed lens group and the focal length of the lens group with the strongest positive refractive power among the multiple lens groups in the variable magnification lens group. Conditional formula (1) enables weight reduction while still providing excellent aberration correction. To reduce weight, the variable magnification lens group is a positive lens group with weak refractive power, which reduces the effect of converging axial rays. However, by placing a lens group with strong positive refractive power in the second fixed lens group, axial rays are converged, allowing the diameter of the subsequent first focus lens group to be reduced. If the lower limit of conditional formula (1) is exceeded, the refractive power of the second fixed lens group becomes too strong, making it difficult to correct various aberrations, such as spherical aberration, that occur in the second fixed lens group. On the other hand, if the upper limit of conditional formula (1) is exceeded, the refractive power of the second fixed lens group becomes too weak, making it impossible to suppress the diameter of the light rays incident on the first focus lens group, and making size reduction difficult.

It should be noted that a greater effect can be obtained by setting the numerical range of conditional expression (1) as in the following conditional expression (1A).
0.15≦ffix/fzp<0.65...(1A)

Furthermore, the zoom lens according to an embodiment may satisfy the following conditional expression (2).
0.0≦(ff1/｜ff1｜)*(dw-dt)/dw≦1.0 ...(2)
however,
ff1: focal length of the first focus lens group, dw: distance on the optical axis from the vertex of the surface of the first focus lens group closest to the object to the image plane when focused at the wide-angle end and at infinity, dt: distance on the optical axis from the vertex of the surface of the first focus lens group closest to the object to the image plane when focused at the telephoto end and at infinity. * indicates a multiplication symbol.

Conditional expression (2) is a conditional expression for establishing an appropriate relationship between the axial distance from the vertex of the surface of the first focus lens group closest to the object to the image plane when focusing at infinity at the wide-angle end and at the telephoto end. Conditional expression (2) appropriately controls the movement trajectory of the first focus lens group during zooming and focusing, minimizing the total stroke amount during movement of the first focus lens group. If the lower limit of conditional expression (2) is exceeded, the focusing position at infinity at the telephoto end, where the stroke is longest for focusing, will be closer to the image plane, increasing the total stroke amount and making compact design difficult. On the other hand, if the upper limit of conditional expression (2) is exceeded, the movement amount of the first focus lens group during zooming will be too large, making compact design difficult.

It should be noted that a better effect can be obtained by setting the numerical range of conditional expression (2) as in the following conditional expression (2A).
0.0≦(ff1/｜ff1｜)*(dw-dt)/dw≦0.3 ...(2A)

In addition, in a zoom lens according to one embodiment, it is preferable that at least two or more of the multiple lens groups in the variable magnification lens group are positioned closer to the image plane at the telephoto end than at the wide-angle end. This allows the height of off-axial rays to be significantly changed in each lens group in the variable magnification lens group, resulting in a configuration that is advantageous for correcting various aberrations such as chromatic aberration of magnification and curvature of field. Note that by positioning three of the multiple lens groups in the variable magnification lens group closer to the image plane at the telephoto end than at the wide-angle end, it becomes a configuration that is even more advantageous for correcting various aberrations.

Furthermore, in a zoom lens according to one embodiment, it is preferable that each of the multiple lens groups in the variable magnification lens group does not move in a reciprocating manner when moving from the wide-angle end to the telephoto end. This makes it possible to suppress fluctuations in decentering of the lens groups that move during zooming, which is advantageous from a mechanical standpoint.

Furthermore, in a zoom lens according to one embodiment, the lens group closest to the object among the multiple lens groups in the variable magnification lens group may be configured to have negative refractive power. This makes it easier to ensure the stroke of the lens group with negative refractive power during zooming, resulting in a configuration advantageous for achieving high magnification.

In addition, in a zoom lens according to one embodiment, the lens group closest to the image plane among the multiple lens groups in the variable magnification lens group may be configured to have positive refractive power. This allows the lens group with positive refractive power to be positioned on the image plane side where the height of the axial ray at the wide-angle end is the highest among the variable magnification lens groups, reducing the diameter of the lens group closer to the image plane than the variable magnification lens group, resulting in a configuration advantageous for compactness.

Furthermore, in a zoom lens according to one embodiment, the multiple lens groups of the variable magnification lens group may be configured to include three lens groups. This allows for a large change in the combined focal length of the variable magnification lens group, suppressing fluctuations in various aberrations due to zooming, and providing an advantageous configuration for improving performance.

Furthermore, in a zoom lens according to one embodiment, it is preferable to configure the variable magnification lens group to have eight or fewer lenses. This not only results in a configuration that is advantageous for reducing the weight of the variable magnification lens group, but also makes it possible to simplify the method of fixing each lens, thereby enabling mechanical weight reduction.

Furthermore, in a zoom lens according to one embodiment, it is preferable to configure the lens group having the largest absolute value of refractive power among the multiple lens groups in the variable magnification lens group to be the lens group having negative refractive power. This makes it easier to ensure the variable magnification ratio of the lens group having negative refractive power in the variable magnification lens group, resulting in a configuration advantageous for achieving high magnification.

Furthermore, in one embodiment of the zoom lens, in addition to the first focus lens group, a second focus lens group that moves together with the first focus lens group during focusing may be further provided. This makes it possible to maintain high optical performance from infinity to subjects at finite distances.

Furthermore, the zoom lens according to an embodiment may satisfy the following conditional expression (3).
0.5<|ff1/ff2|<3.0...(3)
however,
ff1: focal length of the first focus lens group, and ff2: focal length of the second focus lens group.

Conditional formula (3) is a conditional formula for ensuring an appropriate relationship between the ratio of the focal length of the first focus lens group and the focal length of the second focus lens group. Conditional formula (3) enables weight reduction while still providing good aberration correction. Below the lower limit of conditional formula (3), the refractive power of the first focus lens group becomes too strong, making it difficult to correct various aberrations, such as spherical aberration, that occur in the first focus lens group. On the other hand, above the upper limit of conditional formula (3), the refractive power of the first focus lens group becomes too weak, making the stroke of the first focus lens group too long and making it difficult to achieve compactness.

It should be noted that a greater effect can be obtained by setting the numerical range of conditional expression (3) as in the following conditional expression (3A).
0.7<|ff1/ff2|<2.5...(3A)

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

Figure 53 shows an example configuration of an imaging device 100 that uses a zoom lens according to one embodiment. This imaging device 100 is, for example, a digital still camera, and includes a camera block 110, 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 110 is responsible for the imaging function and includes an imaging lens 11 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 11 into an electrical signal, and outputs an imaging signal (image signal) corresponding to the optical image. Zoom lenses 1 to 4 according to the configuration examples shown in Figure 1 and elsewhere can be used as the imaging lens 11.

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 110, and controls motors and the like (not shown) that drive each lens of the imaging lens 11 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 corresponding to an image photographed by the camera block 110 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, for example, the CPU 60 outputs a control signal to the lens drive control unit 80, and a predetermined lens of the imaging lens 11 moves under the control of the lens drive control unit 80.

When the shutter (not shown) of the camera block 110 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 11 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 zoom lens according to an embodiment of the present disclosure will be described. Here, examples will be described in which specific numerical values are applied to the zoom lenses 1 to 4 according to the configuration examples shown in FIG.

The meanings of the symbols used in the tables and explanations below are as follows: "Si" indicates the number of the i-th surface, with the numbers increasing from the closest to the object. "ri" indicates the value (mm) of the paraxial radius of curvature of the i-th surface. "di" indicates the value (mm) of the axial spacing between the i-th surface and the (i+1)-th surface. "ndi" indicates the value of the refractive index at the d-line (wavelength 587.6 nm) of the material of the optical element that makes up the i-th surface. "νdi" indicates the value of the Abbe number at the d-line of the material of the optical element that makes up the i-th surface. "φi" indicates the value (mm) of the effective diameter of the i-th surface. A portion where the value of "ri" is "∞" indicates a flat surface, an aperture surface, etc. "ASP" in the surface number (Si) column indicates that the surface in question is aspherical. "STO" in the surface number column indicates that an aperture stop St is located at the corresponding position. "OBJ" in the surface number column indicates that the surface in question is the object plane (subject plane). "IMG" in the surface number column indicates that the surface in question is the image plane. "f" indicates the focal length of the entire 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 optical length (the distance on the optical axis from the surface closest to the object to the image plane IMG) (unit: mm).

Furthermore, some of the lenses used in each embodiment have aspherical lens surfaces. The aspherical shape is defined by the following formula. In the tables showing aspherical coefficients described below, "E-i" represents an exponential expression with base 10, i.e., "10 ^-i "; for example, "0.12345E-05" represents "0.12345×10 ^-5 ".

(Aspherical surface formula)
x=c ² y ² /(1+(1-(1+k)c ² y ² ) ^1/2 )+A4・y ⁴ +A6・y ⁶ +A8・y ⁸ +A10・y ¹⁰ +A12・y ¹² +A14・y ¹⁴
Here, the distance from the vertex of the lens surface in the optical axis direction (sag amount) is "x," the height in the direction perpendicular to the optical axis is "y," the paraxial curvature (the reciprocal of the radius of curvature) at the vertex of the lens surface is "c," and the conic constant is "k." A4, A6, A8, A10, A12, and A14 are the 4th-, 6th-, 8th-, 10th-, 12th-, and 14th-order aspheric coefficients, respectively.

[Example 1]
Table 1 shows basic lens data for the zoom lens 1 according to Example 1 shown in FIG. 1 . Table 2 shows the focal length f, F-number, total angle of view 2ω, image height Y, and total optical length L of the entire system for the zoom lens 1 according to Example 1. Table 3 shows data on surface spacings that are variable during zooming and focusing for the zoom lens 1 according to Example 1. Table 2 also shows values for the wide-angle end (Wide), the middle position (Mid), and the telephoto end (Tele) when the object distance (d0) is infinity. Table 3 also shows values for the wide-angle end (Wide), the middle position (Mid), and the telephoto end (Tele) when the object distance (d0) is infinity and when the object distance is close. Table 4 shows values of coefficients representing the shape of the aspherical surface for the zoom lens 1 according to Example 1. Table 5 shows the starting surface and focal length (unit: mm) of each lens group in the zoom lens 1 according to Example 1.

The zoom lens 1 according to Example 1 is configured to include a first lens group GR1, a second lens group GR2, a third lens group GR3, a fourth lens group GR4, a fifth lens group GR5 including an aperture stop St, a sixth lens group GR6, a seventh lens group GR7, and an eighth lens group GR8, which are arranged in this order from the object side to the image plane side.

In the zoom lens 1 according to Example 1, the first lens group GR1 corresponds to the first fixed lens group described above. The second to fourth lens groups GR2 to GR4 correspond to the variable magnification lens groups described above. The fifth lens group GR5 corresponds to the second fixed lens group described above. The sixth lens group GR6 corresponds to the first focus lens group described above. The seventh lens group GR7 corresponds to the second focus lens group described above.

The first lens group GR1 has positive refractive power. The first lens group GR1 consists of, in order from the object side to the image plane side, lenses L11 to L13. Lens L11 is a negative meniscus lens with its convex surface facing the object side. Lens L12 is a positive biconvex lens. Lens L13 is a positive meniscus lens with its convex surface facing the object side.

The second lens group GR2 has negative refractive power. The second lens group GR2 consists, in order from the object side to the image plane side, of lens L21 and lens L22. Lens L21 is a positive meniscus lens with its convex surface facing the object side. Lens L22 is a negative meniscus lens with its convex surface facing the object side. Lenses L21 and L22 form a cemented lens.

The third lens group GR3 has positive refractive power. The third lens group GR3 consists of, in order from the object side to the image plane side, lens L31 and lens L32. Lens L31 is a negative meniscus lens with its convex surface facing the object side. Lens L32 is a positive meniscus lens with its convex surface facing the object side.

The fourth lens group GR4 has negative refractive power. The fourth lens group GR4 consists of, in order from the object side to the image plane side, lenses L41 to L43. Lens L41 is a negative meniscus lens with its convex surface facing the object side. Lens L42 is a negative biconcave lens. Lens L43 is a positive meniscus lens with its convex surface facing the object side. Lenses L42 and L43 form a cemented lens.

The fifth lens group GR5 has positive refractive power. From the object side to the image side, the fifth lens group GR5 consists of lenses L51 to L54, an aperture stop St, lenses L55 to L59, and a lens L510. Lens L51 is a positive meniscus lens with its convex surface facing the object side. Lens L52 is a negative meniscus lens with its convex surface facing the object side. Lens L53 is a positive meniscus lens with its convex surface facing the object side. Lenses L52 and L53 form a cemented lens. Lens L54 is a positive meniscus lens with its convex surface facing the object side. Lens L55 is a positive meniscus lens with its convex surface facing the image side. Lens L56 is a negative biconcave lens. Lenses L55 and L56 form a cemented lens. Lens L57 is a negative meniscus lens with its convex surface facing the object side. Lens L58 is a biconvex positive lens. Lenses L57 and L58 form a cemented lens. Lens L59 is a biconvex positive lens. Lens L510 is a negative meniscus lens with its convex surface facing the image plane. Lenses L59 and L510 form a cemented lens.

The sixth lens group GR6 has negative refractive power. The sixth lens group GR6 consists of, in order from the object side to the image plane side, lens L61 and lens L62. Lens L61 is a biconvex positive lens. Lens L62 is a biconcave negative lens. Lenses L61 and L62 form a cemented lens.

The seventh lens group GR7 has positive refractive power. The seventh lens group GR7 is made up of lens L71. Lens L71 is a positive biconvex lens.

The eighth lens group GR8 has negative refractive power. From the object side to the image side, the eighth lens group GR8 consists of a lens L81 and a lens L82. Lens L81 is a negative biconcave lens. Lens L82 is a negative meniscus lens with its convex surface facing the image side.

When focusing from infinity to a close object distance, the zoom lens 1 of Example 1 moves the sixth lens group GR6 toward the image plane, and the seventh lens group GR7 toward the object, along different trajectories in the optical axis direction. The focusing method is not limited to moving the sixth lens group GR6 and the seventh lens group GR7. For example, instead of the seventh lens group GR7, lens L81 may be moved along the optical axis as a focus lens group, or lens L81 may be moved along the optical axis as a focus lens group in addition to the sixth lens group GR6 and the seventh lens group GR7. Furthermore, by moving lenses L57 and L58, which form the cemented lens, in a direction perpendicular to the optical axis as an image stabilization lens group, image stabilization can be achieved against camera shake and the like.

The above configuration allows for a lightweight telephoto zoom lens that delivers high image quality.

Figure 2 shows the longitudinal aberration of the zoom lens 1 of Example 1 at the wide-angle end and when focused at infinity. Figure 3 shows the longitudinal aberration of the zoom lens 1 of Example 1 at an intermediate position and when focused at infinity. Figure 4 shows the longitudinal aberration of the zoom lens 1 of Example 1 at the telephoto end and when focused at infinity. Figure 5 shows the longitudinal aberration of the zoom lens 1 of Example 1 at the wide-angle end and when focused at a close distance. Figure 6 shows the longitudinal aberration of the zoom lens 1 of Example 1 at an intermediate position and when focused at a close distance. Figure 7 shows the longitudinal aberration of the zoom lens 1 of Example 1 at the telephoto end and when focused at a close distance. Figure 8 shows the lateral aberration of the zoom lens 1 of Example 1 at the wide-angle end and when focused at infinity. Figure 9 shows the lateral aberration of the zoom lens 1 of Example 1 at an intermediate position and when focused at infinity. Figure 10 shows the lateral aberration of the zoom lens 1 of Example 1 at the telephoto end and when focused at infinity. FIG. 11 shows the lateral aberration of the zoom lens 1 according to Example 1 at the wide-angle end and when focusing on a close distance. FIG. 12 shows the lateral aberration of the zoom lens 1 according to Example 1 at the intermediate position and when focusing on a close distance. FIG. 13 shows the lateral aberration of the zoom lens 1 according to Example 1 at the telephoto end and when focusing on a close distance.

Figures 2 to 7 show spherical aberration, astigmatism (field curvature), and distortion as longitudinal aberrations. In the spherical aberration diagrams in Figures 2 to 7 and the lateral aberration diagrams in Figures 8 to 13, the solid line indicates values at the d-line (587.56 nm), the dashed-dotted line indicates values at the g-line (435.84 nm), and the dashed line indicates values at the C-line (656.27 nm). In the astigmatism diagrams in Figures 2 to 7, S indicates values at the sagittal image plane, and T indicates values at the tangential image plane. In the astigmatism diagrams and distortion diagrams in Figures 2 to 7, values at the d-line are shown.
The same applies to the aberration diagrams in the other examples that follow.

As can be seen from each aberration diagram, the zoom lens 1 according to Example 1 effectively corrects various aberrations and has excellent imaging performance.

[Example 2]
Table 6 shows basic lens data for the zoom lens 2 according to Example 2 shown in FIG. 14 . Table 7 shows values for the focal length f, F-number, total angle of view 2ω, image height Y, and total optical length L of the entire system for the zoom lens 2 according to Example 2. Table 8 shows data on surface spacings that are variable during zooming and focusing for the zoom lens 2 according to Example 2. Table 7 also shows values for the wide-angle end (Wide), the middle position (Mid), and the telephoto end (Tele) when the object distance (d0) is infinity. Table 8 also shows values for the wide-angle end (Wide), the middle position (Mid), and the telephoto end (Tele) when the object distance (d0) is infinity and when the object distance is close. Table 9 shows values of coefficients representing the shape of the aspherical surface for the zoom lens 2 according to Example 2. Table 10 shows the initial surface and focal length (unit: mm) of each lens group of the zoom lens 2 according to Example 2.

The zoom lens 2 according to Example 2 is configured to include a first lens group GR1, a second lens group GR2, a third lens group GR3, a fourth lens group GR4, a fifth lens group GR5 including an aperture stop St, a sixth lens group GR6, a seventh lens group GR7, and an eighth lens group GR8, which are arranged in this order from the object side to the image plane side.

In the zoom lens 2 according to Example 2, the first lens group GR1 corresponds to the first fixed lens group described above. The second to fourth lens groups GR2 to GR4 correspond to the variable magnification lens group described above. The fifth lens group GR5 corresponds to the second fixed lens group described above. The sixth lens group GR6 corresponds to the first focus lens group described above. The seventh lens group GR7 corresponds to the second focus lens group described above.

The first lens group GR1 has positive refractive power. The first lens group GR1 consists of, in order from the object side to the image plane side, lenses L11 to L13. Lens L11 is a negative meniscus lens with its convex surface facing the object side. Lens L12 is a positive biconvex lens. Lens L13 is a positive meniscus lens with its convex surface facing the object side.

The second lens group GR2 has negative refractive power. The second lens group GR2 is made up of lens L21. Lens L21 is a negative meniscus lens with its convex surface facing the object side.

The third lens group GR3 has negative refractive power. The third lens group GR3 consists of, in order from the object side to the image plane side, lens L31 and lens L32. Lens L31 is a negative biconcave lens. Lens L32 is a positive meniscus lens with its convex surface facing the object side. Lenses L31 and L32 form a cemented lens.

The fourth lens group GR4 has positive refractive power. It consists of lens L41. Lens L41 is a positive meniscus lens with its convex surface facing the object side.

The fifth lens group GR5 has positive refractive power. From the object side to the image plane side, the fifth lens group GR5 consists of lens L51, aperture stop St, and lenses L52 to L55. Lens L51 is a biconvex positive lens. Lens L52 is a biconcave negative lens. Lens L53 is a negative meniscus lens with its convex surface facing the object side. Lens L54 is a biconvex positive lens. Lenses L53 and L54 form a cemented lens. Lens L55 is a biconvex positive lens.

The sixth lens group GR6 has negative refractive power. The sixth lens group GR6 consists of, in order from the object side to the image side, lens L61 and lens L62. Lens L61 is a plano-convex lens with its convex surface facing the image side. Lens L62 is a negative lens with a biconcave shape. Lenses L61 and L62 form a cemented lens.

The seventh lens group GR7 has positive refractive power. The seventh lens group GR7 is made up of lens L71. Lens L71 is a positive biconvex lens.

The eighth lens group GR8 has negative refractive power. From the object side to the image side, the eighth lens group GR8 consists of a lens L81 and a lens L82. Lens L81 is a negative biconcave lens. Lens L82 is a negative meniscus lens with its convex surface facing the image side.

When focusing from infinity to a close object distance, the zoom lens 2 according to Example 2 moves the sixth lens group GR6 toward the image plane and the seventh lens group GR7 toward the object along different trajectories in the optical axis direction. The focusing method is not limited to moving the sixth lens group GR6 and the seventh lens group GR7. For example, instead of the seventh lens group GR7, lens L41 may be moved along the optical axis as a focus lens group, or lens L41 may be moved along the optical axis as a focus lens group in addition to the sixth lens group GR6 and the seventh lens group GR7. Furthermore, by moving lenses L53 and L54, which form the cemented lens, in a direction perpendicular to the optical axis as an image stabilization lens group, image stabilization can be achieved against camera shake and the like.

The above configuration allows for a lightweight telephoto zoom lens that delivers high image quality.

Figure 15 shows the longitudinal aberration of the zoom lens 2 of Example 2 at the wide-angle end and when focused at infinity. Figure 16 shows the longitudinal aberration of the zoom lens 2 of Example 2 at an intermediate position and when focused at infinity. Figure 17 shows the longitudinal aberration of the zoom lens 2 of Example 2 at the telephoto end and when focused at infinity. Figure 18 shows the longitudinal aberration of the zoom lens 2 of Example 2 at the wide-angle end and when focused at a close distance. Figure 19 shows the longitudinal aberration of the zoom lens 2 of Example 2 at an intermediate position and when focused at a close distance. Figure 20 shows the longitudinal aberration of the zoom lens 2 of Example 2 at the telephoto end and when focused at a close distance. Figure 21 shows the lateral aberration of the zoom lens 2 of Example 2 at the wide-angle end and when focused at infinity. Figure 22 shows the lateral aberration of the zoom lens 2 of Example 2 at an intermediate position and when focused at infinity. Figure 23 shows the lateral aberration of the zoom lens 2 of Example 2 at the telephoto end and when focused at infinity. FIG. 24 shows the lateral aberration of the zoom lens 2 according to Example 2 at the wide-angle end and when focusing on a close distance. FIG. 25 shows the lateral aberration of the zoom lens 2 according to Example 2 at the intermediate position and when focusing on a close distance. FIG. 26 shows the lateral aberration of the zoom lens 2 according to Example 2 at the telephoto end and when focusing on a close distance.

As can be seen from each aberration diagram, the zoom lens 2 according to Example 2 has excellent correction for various aberrations and has excellent imaging performance.

[Example 3]
Table 11 shows basic lens data for the zoom lens 3 according to Example 3 shown in FIG. 27 . Table 12 shows values for the focal length f, F-number, total angle of view 2ω, image height Y, and total optical length L of the entire system for the zoom lens 3 according to Example 3. Table 13 shows data on surface spacings that are variable during zooming and focusing for the zoom lens 3 according to Example 3. Table 12 also shows values for the wide-angle end (Wide), the middle position (Mid), and the telephoto end (Tele) when the object distance (d0) is infinity. Table 13 also shows values for the wide-angle end (Wide), the middle position (Mid), and the telephoto end (Tele) when the object distance (d0) is infinity and when the object distance is close. Table 14 shows values of coefficients representing the shape of the aspherical surfaces for the zoom lens 3 according to Example 3. Table 15 shows the initial surface and focal length (unit: mm) of each lens group of the zoom lens 3 according to Example 3.

The zoom lens 3 according to Example 3 is configured to include a first lens group GR1, a second lens group GR2, a third lens group GR3, a fourth lens group GR4, a fifth lens group GR5 including an aperture stop St, a sixth lens group GR6, a seventh lens group GR7, and an eighth lens group GR8, arranged in this order from the object side to the image plane side.

In the zoom lens 3 according to Example 3, the first lens group GR1 corresponds to the first fixed lens group described above. The second to fourth lens groups GR2 to GR4 correspond to the variable magnification lens group described above. The fifth lens group GR5 corresponds to the second fixed lens group described above. The sixth lens group GR6 corresponds to the first focus lens group described above. The seventh lens group GR7 corresponds to the second focus lens group described above.

The first lens group GR1 has positive refractive power. The first lens group GR1 consists of, in order from the object side to the image plane side, lenses L11 to L13. Lens L11 is a negative meniscus lens with its convex surface facing the object side. Lens L12 is a positive biconvex lens. Lens L13 is a positive meniscus lens with its convex surface facing the object side.

The second lens group GR2 has negative refractive power. The second lens group GR2 is made up of lens L21. Lens L21 is a negative meniscus lens with its convex surface facing the object side.

The third lens group GR3 has negative refractive power. The third lens group GR3 consists of, in order from the object side to the image plane side, lens L31 and lens L32. Lens L31 is a negative biconcave lens. Lens L32 is a positive meniscus lens with its convex surface facing the object side. Lenses L31 and L32 form a cemented lens.

The fourth lens group GR4 has positive refractive power. It consists of lens L41. Lens L41 is a positive meniscus lens with its convex surface facing the object side.

The fifth lens group GR5 has positive refractive power. The fifth lens group GR5 consists, in order from the object side to the image side, of lens L51, aperture stop St, and lenses L52 to L55. Lens L51 is a biconvex positive lens. Lens L52 is a negative meniscus lens with its convex surface facing the object side. Lens L53 is a negative meniscus lens with its convex surface facing the object side. Lens L54 is a biconvex positive lens. Lenses L53 and L54 form a cemented lens. Lens L55 is a biconvex positive lens.

The sixth lens group GR6 has negative refractive power. The sixth lens group GR6 consists of, in order from the object side to the image plane side, lenses L61 to L63. Lens L61 is a positive biconvex lens. Lens L62 is a negative biconcave lens. Lenses L61 and L62 form a cemented lens. Lens L63 is a positive meniscus lens with its convex surface facing the object side.

The seventh lens group GR7 has positive refractive power. The seventh lens group GR7 is made up of lens L71. Lens L71 is a positive biconvex lens.

The eighth lens group GR8 has negative refractive power. From the object side to the image side, the eighth lens group GR8 consists of a lens L81 and a lens L82. Lens L81 is a negative biconcave lens. Lens L82 is a negative meniscus lens with its convex surface facing the image side.

When focusing from infinity to a close object distance, the zoom lens 3 according to Example 3 moves the sixth lens group GR6 toward the image plane and the seventh lens group GR7 toward the object along different trajectories in the optical axis direction. The focusing method is not limited to moving the sixth lens group GR6 and the seventh lens group GR7. For example, instead of the seventh lens group GR7, lens L81 may be moved along the optical axis as a focus lens group, or lens L81 may be moved along the optical axis as a focus lens group in addition to the sixth lens group GR6 and the seventh lens group GR7. Furthermore, by moving lenses L53 and L54, which form the cemented lens, in a direction perpendicular to the optical axis as an image stabilization lens group, image stabilization can be achieved against camera shake and the like.

The above configuration allows for a lightweight telephoto zoom lens that delivers high image quality.

Figure 28 shows the longitudinal aberration of the zoom lens 3 of Example 3 at the wide-angle end and when focused on infinity. Figure 29 shows the longitudinal aberration of the zoom lens 3 of Example 3 at an intermediate position and when focused on infinity. Figure 30 shows the longitudinal aberration of the zoom lens 3 of Example 3 at the telephoto end and when focused on infinity. Figure 31 shows the longitudinal aberration of the zoom lens 3 of Example 3 at the wide-angle end and when focused on a close distance. Figure 32 shows the longitudinal aberration of the zoom lens 3 of Example 3 at an intermediate position and when focused on a close distance. Figure 33 shows the longitudinal aberration of the zoom lens 3 of Example 3 at the telephoto end and when focused on a close distance. Figure 34 shows the lateral aberration of the zoom lens 3 of Example 3 at the wide-angle end and when focused on infinity. Figure 35 shows the lateral aberration of the zoom lens 3 of Example 3 at an intermediate position and when focused on infinity. Figure 36 shows the lateral aberration of the zoom lens 3 of Example 3 at the telephoto end and when focused on infinity. FIG. 37 shows the lateral aberration of the zoom lens 3 according to Example 3 at the wide-angle end when focusing on a close distance. FIG. 38 shows the lateral aberration of the zoom lens 3 according to Example 3 at the intermediate position when focusing on a close distance. FIG. 39 shows the lateral aberration of the zoom lens 3 according to Example 3 at the telephoto end when focusing on a close distance.

As can be seen from each aberration diagram, the zoom lens 3 according to Example 3 has excellent correction for various aberrations and has excellent imaging performance.

[Example 4]
Table 16 shows basic lens data for the zoom lens 4 according to Example 4 shown in FIG. 40 . Table 17 shows values for the focal length f, F-number, total angle of view 2ω, image height Y, and total optical length L of the entire system for the zoom lens 4 according to Example 4. Table 18 shows data on surface spacings that are variable during zooming and focusing for the zoom lens 4 according to Example 4. Table 17 also shows values for the wide-angle end (Wide), the middle position (Mid), and the telephoto end (Tele) when the object distance (d0) is infinity. Table 18 also shows values for the wide-angle end (Wide), the middle position (Mid), and the telephoto end (Tele) when the object distance (d0) is infinity and when the object distance is close. Table 19 shows values of coefficients representing the shape of the aspherical surface for the zoom lens 4 according to Example 4. Table 20 shows the initial surface and focal length (unit: mm) of each lens group of the zoom lens 4 according to Example 4.

The zoom lens 4 according to Example 4 is configured to include a first lens group GR1, a second lens group GR2, a third lens group GR3, a fourth lens group GR4, a fifth lens group GR5 including an aperture stop St, a sixth lens group GR6, a seventh lens group GR7, and an eighth lens group GR8, arranged in this order from the object side to the image plane side.

In the zoom lens 4 according to Example 4, the first lens group GR1 corresponds to the first fixed lens group described above. The second to fourth lens groups GR2 to GR4 correspond to the variable magnification lens groups described above. The fifth lens group GR5 corresponds to the second fixed lens group described above. The sixth lens group GR6 corresponds to the first focus lens group described above. The seventh lens group GR7 corresponds to the second focus lens group described above.

The first lens group GR1 has positive refractive power. The first lens group GR1 consists of, in order from the object side to the image plane side, lenses L11 to L13. Lens L11 is a negative meniscus lens with its convex surface facing the object side. Lens L12 is a positive biconvex lens. Lens L13 is a positive meniscus lens with its convex surface facing the object side.

The second lens group GR2 has negative refractive power. The second lens group GR2 is made up of lens L21. Lens L21 is a negative meniscus lens with its convex surface facing the object side.

The third lens group GR3 has negative refractive power. The third lens group GR3 consists of, in order from the object side to the image plane side, lens L31 and lens L32. Lens L31 is a negative biconcave lens. Lens L32 is a positive meniscus lens with its convex surface facing the object side. Lenses L31 and L32 form a cemented lens.

The fourth lens group GR4 has positive refractive power. It consists of lens L41. Lens L41 is a positive meniscus lens with its convex surface facing the object side.

The fifth lens group GR5 has positive refractive power. From the object side to the image plane side, the fifth lens group GR5 consists of lens L51, aperture stop St, and lenses L52 to L54. Lens L51 is a biconvex positive lens. Lens L52 is a biconcave negative lens. Lens L53 is a negative meniscus lens with its convex surface facing the object side. Lens L54 is a biconvex positive lens. Lenses L53 and L54 form a cemented lens.

The sixth lens group GR6 has positive refractive power. The sixth lens group GR6 is made up of lens L61. Lens L61 is a positive biconvex lens.

The seventh lens group GR7 has negative refractive power. The seventh lens group GR7 consists of, in order from the object side to the image side, lens L71 and lens L72. Lens L71 is a plano-convex lens with its convex surface facing the image side. Lens L72 is a negative lens with a biconcave shape. Lenses L71 and L72 form a cemented lens.

The eighth lens group GR8 has positive refractive power. The eighth lens group GR8 consists of, in order from the object side to the image side, lenses L81 to L83. Lens L81 is a positive biconvex lens. Lens L82 is a negative biconcave lens. Lens L83 is a negative meniscus lens with its convex surface facing the image side.

When focusing from infinity to a close object distance, the zoom lens 4 of Example 4 moves the sixth lens group GR6 toward the object, and the seventh lens group GR7 toward the image plane along different trajectories in the optical axis direction. The focusing method is not limited to moving the sixth lens group GR6 and the seventh lens group GR7. For example, instead of the seventh lens group GR7, lens L41 may be moved along the optical axis as a focus lens group, or lens L41 may be moved along the optical axis as a focus lens group in addition to the sixth lens group GR6 and the seventh lens group GR7. Furthermore, by moving lenses L53 and L54, which form the cemented lens, in a direction perpendicular to the optical axis as an image stabilization lens group, image stabilization can be achieved against camera shake and the like.

The above configuration allows for a lightweight telephoto zoom lens that delivers high image quality.

Figure 41 shows the longitudinal aberration of the zoom lens 4 of Example 4 at the wide-angle end and when focused on infinity. Figure 42 shows the longitudinal aberration of the zoom lens 4 of Example 4 at an intermediate position and when focused on infinity. Figure 43 shows the longitudinal aberration of the zoom lens 4 of Example 4 at the telephoto end and when focused on infinity. Figure 44 shows the longitudinal aberration of the zoom lens 4 of Example 4 at the wide-angle end and when focused on a close distance. Figure 45 shows the longitudinal aberration of the zoom lens 4 of Example 4 at an intermediate position and when focused on a close distance. Figure 46 shows the longitudinal aberration of the zoom lens 4 of Example 4 at the telephoto end and when focused on a close distance. Figure 47 shows the lateral aberration of the zoom lens 4 of Example 4 at the wide-angle end and when focused on infinity. Figure 48 shows the lateral aberration of the zoom lens 4 of Example 4 at an intermediate position and when focused on infinity. Figure 49 shows the lateral aberration of the zoom lens 4 of Example 4 at the telephoto end and when focused on infinity. Figure 50 shows the lateral aberration of the zoom lens 4 according to Example 4 at the wide-angle end when focusing on a close distance. Figure 51 shows the lateral aberration of the zoom lens 4 according to Example 4 at the intermediate position when focusing on a close distance. Figure 52 shows the lateral aberration of the zoom lens 4 according to Example 4 at the telephoto end when focusing on a close distance.

As can be seen from each aberration diagram, the zoom lens 4 according to Example 4 has excellent correction for various aberrations and has excellent imaging performance.

[Other Numerical Data for Each Example]
Tables 21 and 22 show the values for each of the above conditional expressions for each example. As can be seen from Tables 21 and 22, the values for each example fall within the numerical ranges for conditional expressions (1) to (3).

<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. 54 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. 54, 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 a Controller Area Network (CAN), a Local Interconnect Network (LIN), a Local Area Network (LAN), or FlexRay (registered trademark).

Each control unit includes a microcomputer that performs arithmetic processing in accordance with 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 54 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 55 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 top 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 top 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 top 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 55 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 54, 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. 54, 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 an eyeglass-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. 54, 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 zoom lens and imaging device of the present disclosure 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 can be applied to a medical imaging system, which is a medical system that uses imaging technology, such as an endoscope system or a microscope system.

[Endoscope system]
An example of an endoscopic system will be described with reference to FIGS. 56 and 57 . FIG. 56 is a diagram illustrating an example of a schematic configuration of an endoscopic system 5000 to which the technology according to the present disclosure can be applied. FIG. 57 is a diagram illustrating an example of the configuration of an endoscope 5001 and a CCU (Camera Control Unit) 5039. FIG. 56 illustrates a state in which an operator (e.g., a doctor) 5067, who is a surgical participant, is performing surgery on a patient 5071 on a patient bed 5069 using the endoscopic system 5000. As shown in FIG. 56 , the endoscopic system 5000 includes an endoscope 5001, which is a medical imaging device, a CCU 5039, a light source device 5043, a recording device 5053, an output device 5055, and a support device 5027 that supports the endoscope 5001.

In endoscopic surgery, an insertion aid called a trocar 5025 is inserted into the patient 5071. Then, a scope 5003 and surgical tools 5021 connected to an endoscope 5001 are inserted into the body of the patient 5071 via the trocar 5025. The surgical tools 5021 are, for example, energy devices such as electric scalpels, or forceps.

Surgical images, which are medical images showing the inside of the body of a patient 5071 captured by an endoscope 5001, are displayed on a display device 5041. A surgeon 5067 performs treatment on the surgical subject using surgical tools 5021 while viewing the surgical images displayed on the display device 5041. Note that medical images are not limited to surgical images, and may also be diagnostic images captured during a diagnosis.

[Endoscope]
The endoscope 5001 is an imaging unit that captures images of the inside of the patient's 5071. For example, as shown in FIG. 57 , the endoscope 5001 is a camera 5005 that includes a focusing optical system 50051 that focuses incident light, a zoom optical system 50052 that changes the focal length of the imaging unit to enable optical zoom, a focus optical system 50053 that changes the focal length of the imaging unit to enable focus adjustment, and a light-receiving element 50054. The endoscope 5001 generates pixel signals by focusing light onto the light-receiving element 50054 via a connected scope 5003, and outputs the pixel signals to the CCU 5039 via a transmission system. The scope 5003 has an objective lens at its tip and is an insertion section that guides light from a connected light source device 5043 into the inside of the patient's 5071. The scope 5003 is, for example, a rigid scope for rigid endoscopes or a flexible scope for flexible endoscopes. The scope 5003 may be a direct endoscope or an oblique endoscope. Furthermore, the pixel signal may be a signal based on a signal output from a pixel, such as a RAW signal or an image signal. Furthermore, a configuration may be adopted in which a memory is installed in the transmission system connecting the endoscope 5001 and the CCU 5039, and parameters related to the endoscope 5001 and the CCU 5039 are stored in the memory. The memory may be located, for example, in a connection portion of the transmission system or on a cable. For example, parameters at the time of shipment of the endoscope 5001 and parameters that change when power is applied may be stored in the memory of the transmission system, and the operation of the endoscope may be changed based on parameters read from the memory. Furthermore, the endoscope and the transmission system may be collectively referred to as an endoscope. The light-receiving element 50054 is a sensor that converts received light into a pixel signal, and is, for example, a CMOS (Complementary Metal Oxide Semiconductor) type image sensor. It is preferable that the light-receiving element 50054 be an image sensor capable of color imaging with a Bayer array. Furthermore, the light receiving element 50054 is preferably an imaging element having a number of pixels corresponding to a resolution of, for example, 4K (3840 horizontal pixels × 2160 vertical pixels), 8K (7680 horizontal pixels × 4320 vertical pixels), or square 4K (3840 or more horizontal pixels × 3840 or more vertical pixels). The light receiving element 50054 may be a single sensor chip or multiple sensor chips. For example, a prism may be provided to separate incident light into predetermined wavelength bands, and each wavelength band may be captured by a different light receiving element. Multiple light receiving elements may also be provided for stereoscopic vision. The light receiving element 50054 may also be a sensor including an arithmetic processing circuit for image processing within its chip structure, or a Time of Flight (ToF) sensor. The transmission system may be, for example, an optical fiber cable or wireless transmission. The wireless transmission may be any method as long as it is capable of transmitting pixel signals generated by the endoscope 5001. For example, the endoscope 5001 and the CCU 5039 may be connected wirelessly, or the endoscope 5001 and the CCU 5039 may be connected via a base station in the operating room. In this case, the endoscope 5001 may simultaneously transmit not only the pixel signals but also information related to the pixel signals (for example, the processing priority of the pixel signals, a synchronization signal, etc.). Note that the endoscope may be configured such that the scope and camera are integrated, or a light-receiving element is provided at the tip of the scope.

[CCU (Camera Control Unit)]
The CCU 5039 is a control device that comprehensively controls the connected endoscope 5001 and light source device 5043, and is, for example, an information processing device having an FPGA 50391, a CPU 50392, a RAM 50393, a ROM 50394, a GPU 50395, and an I/F 50396, as shown in FIG. 57 . The CCU 5039 may also comprehensively control the connected display device 5041, recording device 5053, and output device 5055. For example, the CCU 5039 controls the irradiation timing, irradiation intensity, and type of irradiation light source of the light source device 5043. The CCU 5039 also performs image processing such as development processing (e.g., demosaic processing) and correction processing on pixel signals output from the endoscope 5001, and outputs the processed pixel signals (e.g., an image) to an external device such as the display device 5041. Furthermore, the CCU 5039 transmits a control signal to the endoscope 5001 to control the driving of the endoscope 5001. The control signal is, for example, information regarding imaging conditions such as the magnification and focal length of the imaging unit. The CCU 5039 may have an image down-conversion function and be configured to be able to simultaneously output a high-resolution (e.g., 4K) image to the display device 5041 and a low-resolution (e.g., HD) image to the recording device 5053.

The CCU 5039 may also be connected to external devices (e.g., recording devices, display devices, output devices, support devices) via an IP converter that converts signals into a specified communication protocol (e.g., IP (Internet Protocol)). The connection between the IP converter and external devices may be configured via a wired network, or part or all of the network may be constructed as a wireless network. For example, the IP converter on the CCU 5039 side may have wireless communication capabilities, and may transmit received video to an IP switcher or output-side IP converter via a wireless communication network such as a fifth-generation mobile communication system (5G) or sixth-generation mobile communication system (6G).

[Light source device]
The light source device 5043 is a device capable of emitting light in a predetermined wavelength band and includes, for example, multiple light sources and a light source optical system that guides the light from the multiple light sources. The light sources are, for example, a xenon lamp, an LED light source, or an LD light source. The light source device 5043 has, for example, LED light sources corresponding to the three primary colors R, G, and B, and emits white light by controlling the output intensity and output timing of each light source. Furthermore, the light source device 5043 may include a light source capable of emitting special light used for special light observation, in addition to a light source that emits normal light used for normal light observation. The special light is light in a predetermined wavelength band different from the normal light used for normal light observation, such as near-infrared light (light with a wavelength of 760 nm or more), infrared light, blue light, or ultraviolet light. The normal light is, for example, white light or green light. Narrowband light observation, a type of special light observation, alternately emits blue light and green light, thereby utilizing the wavelength-dependence of light absorption in body tissue to enable high-contrast imaging of specific tissue, such as blood vessels on the surface of mucous membranes. Furthermore, in fluorescence observation, a type of special light observation, excitation light is applied to excite a drug injected into the body tissue, and fluorescence emitted by the drug as a marker is received to obtain a fluorescence image, thereby making it easier for the surgeon to visualize body tissues that are difficult for the surgeon to see under normal light. For example, in fluorescence observation using infrared light, infrared light having an excitation wavelength band is applied to a drug such as indocyanine green (ICG) injected into the body tissue, and the fluorescence of the drug is received, making it easier to visualize the structure of the body tissue and affected areas. Furthermore, in fluorescence observation, a drug (e.g., 5-ALA) that is excited by special light in the blue wavelength band and emits fluorescence in the red wavelength band may be used. The type of light irradiated by the light source device 5043 is set under the control of the CCU 5039. The CCU 5039 may have a mode in which normal light observation and special light observation are alternately performed by controlling the light source device 5043 and the endoscope 5001. In this case, it is preferable to superimpose information based on pixel signals obtained by special light observation on pixel signals obtained by normal light observation. The special light observation may be infrared light observation, which irradiates infrared light to view areas deeper than the surface of an organ, or multispectral observation using hyperspectral spectroscopy. Furthermore, photodynamic therapy may be combined.

[Recording device]
The recording device 5053 is a device, such as a recorder, that records pixel signals (e.g., images) acquired from the CCU 5039. The recording device 5053 records images acquired from the CCU 5039 on a HDD, SSD, or optical disk. The recording device 5053 may be connected to an intra-hospital network and may be accessible from devices outside the operating room. The recording device 5053 may also have an image down-conversion or up-conversion function.

[Display device]
The display device 5041 is a device capable of displaying an image, such as a display monitor. The display device 5041 displays an image based on pixel signals acquired from the CCU 5039. The display device 5041 may also function as an input device that enables gaze recognition, voice recognition, and instruction input using gestures by including a camera and a microphone.

[Output device]
The output device 5055 is a device, such as a printer, that outputs information acquired from the CCU 5039. The output device 5055 prints, for example, a print image based on pixel signals acquired from the CCU 5039 onto paper.

[Support device]
The support device 5027 is an articulated arm including a base 5029 having an arm control device 5045, an arm 5031 extending from the base 5029, and a holder 5032 attached to the tip of the arm 5031. The arm control device 5045 is configured with a processor such as a CPU and controls the drive of the arm 5031 by operating according to a predetermined program. The support device 5027 controls the position and posture of the endoscope 5001 held by the holder 5032, for example, by controlling parameters such as the length of each link 5035 constituting the arm 5031 and the rotation angle and torque of each joint 5033 using the arm control device 5045. This allows the endoscope 5001 to be changed to a desired position or posture, allowing the scope 5003 to be inserted into the patient 5071 and the observation area within the body to be changed. The support device 5027 functions as an endoscope support arm that supports the endoscope 5001 during surgery. This allows the support device 5027 to take the place of an assistant scopist who holds the endoscope 5001. The support device 5027 may also be a device that supports a microscope device 5301 (described later) and may also be called a medical support arm. The support device 5027 may be controlled autonomously by the arm control device 5045, or may be controlled by the arm control device 5045 based on user input. For example, the control method may be a master-slave method in which the support device 5027, which serves as a slave device (replica device) serving as a patient cart, is controlled based on the movement of a master device (primary device) that serves as an operator console near the user. The support device 5027 may also be remotely controlled from outside the operating room.

The above describes an example of an endoscope system 5000 to which the technology disclosed herein can be applied. For example, the technology disclosed herein may also be applied to a microscope system.

[Microscope system]
58 is a diagram showing an example of a schematic configuration of a microsurgical system to which the technology according to the present disclosure can be applied. In the following description, components similar to those in the endoscope system 5000 are assigned the same reference numerals, and redundant description thereof will be omitted.

Figure 58 shows a schematic diagram of an operator 5067 performing surgery on a patient 5071 on a patient bed 5069 using a microsurgical system 5300. For simplicity, Figure 58 omits the illustration of the cart 5037, which is part of the microsurgical system 5300, and also shows a simplified illustration of the microscope device 5301 that replaces the endoscope 5001. However, the microscope device 5301 in this description may refer to the microscope unit 5303 provided at the tip of the link 5035, or may refer to the entire configuration including the microscope unit 5303 and the support device 5027.

As shown in Figure 58, during surgery, a microsurgical system 5300 is used to display an enlarged image of the surgical site captured by a microscope device 5301 on a display device 5041 installed in the operating room. The display device 5041 is installed in a position facing the surgeon 5067, who performs various procedures on the surgical site, such as resecting the affected area, while observing the state of the surgical site using the image displayed on the display device 5041. Microsurgical systems are used, for example, in ophthalmic surgery and brain surgery.

The foregoing describes examples of an endoscopic system 5000 and a microsurgery system 5300 to which the technology disclosed herein can be applied. Note that the systems to which the technology disclosed herein can be applied are not limited to these examples. For example, the support device 5027 may support another observation device or another surgical tool at its tip instead of the endoscope 5001 or microscope unit 5303. Examples of such other observation devices include forceps, a surgeon, an insufflation tube for insufflation, or an energy treatment tool for incising tissue or sealing blood vessels by cauterization. Supporting these observation devices and surgical tools with a support device allows them to be more stably fixed in position than when medical staff support them manually, and also reduces the burden on medical staff. The technology disclosed herein may be applied to support devices that support components other than such a microscope unit.

The technology disclosed herein can be suitably applied to the camera 5005, which has the configuration described above. In particular, the zoom lens disclosed herein can be suitably applied to at least some of the optical systems of the camera 5005: the focusing optical system 50051, the zoom optical system 50052, and the focus optical system 50053.

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

For example, the shapes and numerical values of each part shown in the above embodiment and 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, for example, the configuration may include a number of lenses different from the number of lenses shown in the above embodiment and example. Furthermore, the configuration may include an additional lens that has substantially no refractive power.

For example, the present technology can be configured as follows.
According to the present technology having the following configuration, the configuration of each lens group is optimized so that it is possible to effectively correct various aberrations while being lightweight, thereby making it possible to provide a zoom lens that is lightweight yet capable of effectively correcting various aberrations, and an imaging device equipped with such a zoom lens.

[1]
From the object side to the image plane side,
a first fixed lens group that is fixed during zooming;
a variable magnification lens group that is disposed closer to the object than the aperture stop and has a plurality of lens groups including a positive lens group and a negative lens group that move along different loci when the magnification is changed;
a second fixed lens group having positive refractive power and fixed during zooming;
a first focus lens group disposed adjacent to the second fixed lens group on the image plane side and moving during zooming and focusing;
the lens group having the largest absolute value of refractive power among the plurality of lens groups of the variable magnification lens group is composed of three or less lenses,
A zoom lens that satisfies the following conditional expression:
0.05≦ffix/fzp<0.67...(1)
however,
fzp: focal length of the lens group having the largest positive refractive power among the plurality of lens groups in the variable magnification lens group; and ffix: focal length of the second fixed lens group.
[2]
The zoom lens according to the above item [1] further satisfies the following conditional expression:
0.0≦(ff1/｜ff1｜)*(dw-dt)/dw≦1.0 ...(2)
however,
ff1: focal length of the first focus lens group; dw: distance on the optical axis from the vertex of the surface of the first focus lens group closest to the object to the image plane when at the wide-angle end and focusing at infinity; dt: distance on the optical axis from the vertex of the surface of the first focus lens group closest to the object to the image plane when at the telephoto end and focusing at infinity.
[3]
The zoom lens according to the above [1] or [2], wherein at least two or more lens groups among the plurality of lens groups of the variable magnification lens group are positioned closer to the image plane at a telephoto end than at a wide-angle end.
[4]
The zoom lens according to any one of [1] to [3] above, wherein each of the plurality of lens groups of the variable magnification lens group does not move in a reciprocating manner when moving from a wide-angle end to a telephoto end.
[5]
The zoom lens according to any one of the above [1] to [4], wherein the lens group closest to the object side among the plurality of lens groups in the variable magnification lens group has negative refractive power.
[6]
The zoom lens according to any one of the above [1] to [5], wherein the lens group closest to the image plane among the plurality of lens groups in the variable magnification lens group has a positive refractive power.
[7]
The zoom lens according to any one of [1] to [6] above, wherein the plurality of lens groups of the variable magnification lens group includes three lens groups.
[8]
The zoom lens according to any one of [1] to [7] above, wherein the number of lenses constituting the variable magnification lens group is eight or less.
[9]
The zoom lens according to any one of [1] to [8] above, wherein the lens group having the largest absolute value of refractive power among the plurality of lens groups of the variable magnification lens group is a lens group having negative refractive power.
[10]
The zoom lens according to any one of [1] to [9] above, further comprising: a second focus lens group that moves together with the first focus lens group during focusing.
[11]
The zoom lens according to the above [10] further satisfies the following conditional expression:
however,
ff1: focal length of the first focus lens group, and ff2: focal length of the second focus lens group.
[12]
From the object side to the image plane side,
a first fixed lens group that is fixed during zooming;
a variable magnification lens group that is disposed closer to the object than the aperture stop and has a plurality of lens groups including a positive lens group and a negative lens group that move along different loci when the magnification is changed;
a second fixed lens group having positive refractive power and fixed during zooming;
a first focus lens group disposed adjacent to the second fixed lens group on the image plane side and moving during zooming and focusing;
the plurality of lens groups of the variable magnification lens group are configured by three lens groups,
A zoom lens that satisfies the following conditional expression:
0.05≦ffix/fzp<0.67...(1)
however,
fzp: focal length of the lens group having the largest positive refractive power among the plurality of lens groups in the variable magnification lens group; and ffix: focal length of the second fixed lens group.
[13]
a zoom lens and an imaging element that outputs an imaging signal corresponding to an optical image formed by the zoom lens;
The zoom lens is
From the object side to the image plane side,
a first fixed lens group that is fixed during zooming;
a variable magnification lens group that is disposed closer to the object than the aperture stop and has a plurality of lens groups including a positive lens group and a negative lens group that move along different loci when the magnification is changed;
a second fixed lens group having positive refractive power and fixed during zooming;
a first focus lens group disposed adjacent to the second fixed lens group on the image plane side and moving during zooming and focusing;
the lens group having the largest absolute value of refractive power among the plurality of lens groups of the variable magnification lens group is composed of three or less lenses,
An imaging device that satisfies the following conditional expression:
0.05≦ffix/fzp<0.67...(1)
however,
fzp: focal length of the lens group having the largest positive refractive power among the plurality of lens groups in the variable magnification lens group; and ffix: focal length of the second fixed lens group.
[14]
a zoom lens and an imaging element that outputs an imaging signal corresponding to an optical image formed by the zoom lens;
The zoom lens is
From the object side to the image plane side,
a first fixed lens group that is fixed during zooming;
a variable magnification lens group that is disposed closer to the object than the aperture stop and has a plurality of lens groups including a positive lens group and a negative lens group that move along different loci when the magnification is changed;
a second fixed lens group having positive refractive power and fixed during zooming;
a first focus lens group disposed adjacent to the second fixed lens group on the image plane side and moving during zooming and focusing;
the plurality of lens groups of the variable magnification lens group are configured by three lens groups,
An imaging device that satisfies the following conditional expression:
0.05≦ffix/fzp<0.67...(1)
however,
fzp: focal length of the lens group having the largest positive refractive power among the plurality of lens groups in the variable magnification lens group; and ffix: focal length of the second fixed lens group.
[15]
The zoom lens according to any one of the above [1] to [12], further comprising a lens having substantially no refractive power.
[ 16 ]
The imaging device according to the above [13] or [14], wherein the zoom lens further comprises a lens having substantially no refractive power.

GR1...first lens group (first fixed lens group), GR2...second lens group (variable lens group), GR3...third lens group (variable lens group), GR4...fourth lens group (variable lens group), GR5...fifth lens group (second fixed lens group), GR6...sixth lens group (first focus lens group), GR7...seventh lens group (second focus lens group), GR8...eighth lens group, IMG...image plane, St...aperture diaphragm, Z1...optical axis, 1-4...zoom lens, 110...camera block, 11...imaging lens, 112...imaging element, 20...camera signal processing unit, 30...image processing unit, 40...LCD, 50...R/W (reader/writer), 60...CPU, 70...input unit, 80...lens drive control unit, 100...imaging device, 1000...memory card, 5005...camera, 50051...light-collecting optical system, 50052...zoom optical system, 50053...focus optical system, 50054...light-receiving element, 7410...imaging unit, 7910, 7912, 7914, 7916, 7918...imaging units.

Claims (13)

From the object side to the image plane side,
a first fixed lens group that is fixed during zooming;
a variable magnification lens group that is disposed closer to the object than the aperture stop and has a plurality of lens groups including a positive lens group and a negative lens group that move along different loci when the magnification is changed;
a second fixed lens group having positive refractive power and fixed during zooming;
a first focus lens group disposed adjacent to the second fixed lens group on the image plane side and moving during zooming and focusing;
the plurality of lens groups of the variable magnification lens group include three lens groups,
the lens group having the largest absolute value of refractive power among the plurality of lens groups of the variable magnification lens group is composed of three or less lenses,
A zoom lens that satisfies the following conditional expression:
0.05≦ffix/fzp<0.67...(1)
however,
fzp: focal length of the lens group having the largest positive refractive power among the plurality of lens groups in the variable magnification lens group; and ffix: focal length of the second fixed lens group. From the object side to the image plane side,
a first fixed lens group that is fixed during zooming;
a variable magnification lens group that is disposed closer to the object than the aperture stop and has a plurality of lens groups including a positive lens group and a negative lens group that move along different loci when the magnification is changed;
a second fixed lens group having positive refractive power and fixed during zooming;
a first focus lens group disposed adjacent to the second fixed lens group on the image plane side and moving during zooming and focusing;
a second focus lens group that moves together with the first focus lens group during focusing;
Equipped with
the lens group having the largest absolute value of refractive power among the plurality of lens groups of the variable magnification lens group is composed of three or less lenses,
The following condition is satisfied:
Zoom lens.
0.05≦ffix/fzp<0.67...(1)
0.5<|ff1/ff2|<3.0...(3)
however,
fzp: focal length of the lens group having the largest positive refractive power among the plurality of lens groups in the variable magnification lens group
ffix: focal length of the second fixed lens group
ff1: focal length of the first focus lens group
ff2: focal length of the second focus lens group
Let's say. 3. The zoom lens according to claim 1 , further satisfying the following conditional expression:
0.0≦(ff1/｜ff1｜)*(dw-dt)/dw≦1.0 ...(2)
however,
ff1: focal length of the first focus lens group; dw: distance on the optical axis from the vertex of the surface of the first focus lens group closest to the object to the image plane when at the wide-angle end and focusing at infinity; dt: distance on the optical axis from the vertex of the surface of the first focus lens group closest to the object to the image plane when at the telephoto end and focusing at infinity. 3. The zoom lens according to claim 1, wherein at least two or more of the plurality of lens groups in the variable magnification lens group are positioned closer to the image plane at a telephoto end than at a wide-angle end. 3. The zoom lens according to claim 1, wherein each of the plurality of lens groups of the variable magnification lens group does not move in a reciprocating manner when moving from a wide-angle end to a telephoto end. 3. The zoom lens according to claim 1, wherein the lens group closest to the object side among the plurality of lens groups in the variable magnification lens group has negative refractive power. 3. The zoom lens according to claim 1, wherein the lens group closest to the image plane among the plurality of lens groups in the variable magnification lens group has positive refractive power. 3. The zoom lens according to claim 1, wherein the number of lenses constituting the variable magnification lens group is eight or less. 3. The zoom lens according to claim 1, wherein the lens group having the largest absolute value of refractive power among the plurality of lens groups in the variable magnification lens group is a lens group having negative refractive power. a zoom lens and an imaging element that outputs an imaging signal corresponding to an optical image formed by the zoom lens;
The zoom lens is
From the object side to the image plane side,
a first fixed lens group that is fixed during zooming;
a variable magnification lens group that is disposed closer to the object than the aperture stop and has a plurality of lens groups including a positive lens group and a negative lens group that move along different loci when the magnification is changed;
a second fixed lens group having positive refractive power and fixed during zooming;
a first focus lens group disposed adjacent to the second fixed lens group on the image plane side and moving during zooming and focusing;
the plurality of lens groups of the variable magnification lens group include three lens groups,
the lens group having the largest absolute value of refractive power among the plurality of lens groups of the variable magnification lens group is composed of three or less lenses,
An imaging device that satisfies the following conditional expression:
0.05≦ffix/fzp<0.67...(1)
however,
fzp: focal length of the lens group having the largest positive refractive power among the plurality of lens groups in the variable magnification lens group; and ffix: focal length of the second fixed lens group. a zoom lens and an imaging element that outputs an imaging signal corresponding to an optical image formed by the zoom lens;
The zoom lens is
From the object side to the image plane side,
a first fixed lens group that is fixed during zooming;
a variable magnification lens group that is disposed closer to the object than the aperture stop and has a plurality of lens groups including a positive lens group and a negative lens group that move along different loci when the magnification is changed;
a second fixed lens group having positive refractive power and fixed during zooming;
a first focus lens group disposed adjacent to the second fixed lens group on the image plane side and moving during zooming and focusing ;
a second focus lens group that moves together with the first focus lens group during focusing;
Equipped with
the lens group having the largest absolute value of refractive power among the plurality of lens groups of the variable magnification lens group is composed of three or less lenses ,
An imaging device that satisfies the following conditional expression:
0.05≦ffix/fzp<0.67...(1)
0.5<|ff1/ff2|<3.0...(3)
however,
fzp: focal length of the lens group having the largest positive refractive power among the plurality of lens groups in the variable magnification lens group; ffix: focal length of the second fixed lens group;
ff1: focal length of the first focus lens group
ff2: focal length of the second focus lens group
Let's say. 10. The zoom lens according to claim 1, further comprising a lens having substantially no refractive power. The imaging device according to claim 10 or 11 , wherein the zoom lens further comprises a lens having substantially no refractive power.