JP7422452B2 - Lens equipment and camera systems - Google Patents

Description

The present invention relates to a lens device and a camera system.

A positive lead type zoom lens in which a lens group with a positive refractive power is disposed closest to the object side is known as a zoom lens that can be relatively easily increased in magnification. For example, Patent Document 1 discloses a zoom lens in which a lens group having a positive refractive power disposed closest to the object side is moved toward the object side during zooming from a wide-angle end to a telephoto end. In this zoom lens, the relatively lightweight fifth lens group is moved during focusing.

Japanese Patent Application Publication No. 2011-090190

When increasing the aperture of the zoom lens disclosed in Patent Document 1, aberration fluctuations tend to increase during focusing. Furthermore, when attempting to suppress the aberration fluctuations, the weight of a lens group (hereinafter referred to as a focus group) that is moved during focusing tends to increase.

When the focus group is relatively heavy, in order to improve the drive efficiency of the motor for moving the focus group, it is necessary to provide a booster circuit that boosts the voltage supplied to the motor. However, if the booster circuit is installed at an inappropriate position without considering the configuration of the optical system of the lens device, the outer diameter of the lens device may become large, and the magnetic field generated from the coil included in the booster circuit may cause damage to the camera. There is a risk that noise may be superimposed on the image signal acquired by the image sensor.

SUMMARY OF THE INVENTION An object of the present invention is to provide a lens device and a camera system that can reduce noise in image signals acquired by an image sensor while making the lens device compact.

The lens device of the present invention includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, which are arranged in order from the object side to the image side, and a rear lens group having an overall positive refractive power in the entire zoom range. an optical system in which the distance between adjacent lens groups changes during zooming, and the first lens group moves toward the object side during zooming from a wide-angle end to a telephoto end; a transformer including a coil; and a transformer including a coil. an actuator that is driven by an output voltage from the optical system and moves a part of the lens part of the optical system during focusing, and the coil is arranged to move a part of the lens part of the optical system at the wide-angle end in the optical axis direction. is located at a position farther from the image side than the maximum movement amount of the first lens group from the position of and at a position closer to the object side than the most image-side surface of the optical system and the most object-side position of the actuator at the wide-angle end. It is characterized by

According to the present invention, it is possible to reduce noise in an image signal acquired by an image sensor while configuring a lens device in a small size.

FIG. 1 is a diagram showing the configuration of a lens device according to a first embodiment. FIG. 3 is a diagram for explaining a focus mechanism. FIG. 3 is a cross-sectional view of the configuration around the motor unit. FIG. 3 is a perspective view showing the configuration of a motor unit. FIG. 2 is a perspective view of main parts showing the connection between a drive board and a control board. 3 is a cross-sectional view of the optical system of Example 1. FIG. 3 is an aberration diagram of the optical system of Example 1. FIG. FIG. 3 is a cross-sectional view of the optical system of Example 2. FIG. 7 is an aberration diagram of the optical system of Example 2. FIG. 3 is a cross-sectional view of the optical system of Example 3. FIG. 7 is an aberration diagram of the optical system of Example 3. FIG. 4 is a cross-sectional view of the optical system of Example 4. FIG. 4 is an aberration diagram of the optical system of Example 4. FIG. 5 is a cross-sectional view of the optical system of Example 5. FIG. 7 is an aberration diagram of the optical system of Example 5. FIG. 7 is a cross-sectional view of the optical system of Example 6. FIG. 6 is an aberration diagram of the optical system of Example 6. It is a figure showing the composition of the lens device of a 2nd embodiment. FIG. 1 is a diagram showing the configuration of a camera system.

EMBODIMENT OF THE INVENTION Hereinafter, a lens device and a camera system according to an embodiment of the present invention will be described in detail based on the accompanying drawings. Note that in each figure, the same components are denoted by the same reference numerals, and redundant explanations will be omitted.

[Configuration of lens device]
(About the main configuration)
FIG. 1 is a diagram showing the configuration of a lens device 200 according to the first embodiment. The lens device 200 is an optical system OL (that is, a zoom lens) with a variable focal length, and FIG. 1(a) is a cross-sectional view of the lens device 200 at the wide-angle end, and FIG. 1(b) is a cross-sectional view of the lens device 200 at the telephoto end. FIG. 2 is a cross-sectional view of a lens device 200.

The lens device 200 is an interchangeable lens that can be attached to and detached from a camera body (described later). The lens device 200 includes an optical system OL, a member (described later) that holds the optical system OL, a voltage transformer including a coil, and an actuator (described later) that moves a part of the lens portion of the optical system OL during focusing. The image formed by the optical system OL is then read out as an image signal by an image sensor (described later) disposed within the camera body.

First, the main configuration of the optical system OL will be explained using FIG. 6. FIG. 6 is a diagram showing the configuration of an embodiment of the optical system OL. The optical system OL includes a plurality of lens groups in which the distance between adjacent lens groups changes during zooming. The plurality of lens groups include a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, and a positive refractive power as a whole in the entire zoom range, which are arranged in order from the object side to the image side. It consists of the rear group LR. Then, during zooming from the wide-angle end to the telephoto end, the first lens group L1 moves toward the object side. Furthermore, some lens units of the optical system OL (second lens group L2 in FIG. 6) function as a focus group that moves during focusing. The focus group is illustrated using the symbol Lf in FIG. The first and second lenses from the object side of the first lens group L1 are illustrated using the reference numeral 220 in FIG.

Generally, in the case of a refractive power configuration like the optical system OL, the outer diameter of the first lens group L1 tends to be larger than that of the other lens groups. Furthermore, since the first lens group L1 moves toward the object side during zooming, an actuator is used to move the focus group Lf to the object side of the first lens group L1 or to the outside of the first lens group (in the direction perpendicular to the optical axis). etc. is difficult to arrange.

Returning to the explanation of FIG. 1, the configuration other than the optical system OL will be explained. In addition, in this specification, the expression that members are fixed to each other means that the members are configured to reduce relative positional deviation in a predetermined direction by means of fixing means (not shown) such as screws or adhesive material. shows.

The lens device 200 includes an exterior tube 211, a mount ring 212 fixed to the exterior tube 211 on the image side of the exterior tube 211, and a mount fixed to the mount ring 212 on the image side of the mount ring 212. The main external appearance is formed by the portion 213. A guide tube 201 is arranged inside the exterior tube 211 and fixed to the exterior tube 211 .

(About the zoom mechanism)
The cam ring 202 is a member that rotates integrally with the zoom ring 210 as the zoom ring 210 is rotated. The cam ring 202 is fixed to the guide tube 201 at a fixed position in the optical axis direction and rotatably in the rotational direction.

The holding member 221 holds the first lens group L1 and moves in the optical axis direction together with the first lens group L1. The holding member is fixed to the straight cylinder 222. The linear tube 222 has cam followers 222a arranged at three locations in the circumferential direction with respect to the optical axis, and the cam followers 222a engage with the linear groove (guide groove) 201a of the guide tube 201 and the cam 202a of the cam ring 202. . When the zoom ring 210 is operated by the user, the cam ring 202 rotates with respect to the guide tube 201, and the linear tube 222 and the holding member 221 move in the optical axis direction. Regarding other lens groups that move during zooming, the cam ring 202 rotates with respect to the guide tube 201, similarly to the first lens group L1, so that the holding member that holds the other lens groups moves in the optical axis direction. Moving.

(About the focus mechanism)
The focus group Lf is held in a focus lens barrel 204. The motor unit 100 is an actuator for moving the focus group Lf in the optical axis direction during focusing. The drive board 301 is a means for boosting the voltage supplied to the motor unit 100 (voltage transformation means). The control board 214 has a function as a control section that controls driving of the motor unit. Further, the control board 214 has a function as a communication unit for communicating with the camera. The specific functions and arrangement of the drive board 301, control board 214, flexible printed circuit board 214a (hereinafter referred to as FPC board 214a), and electrical contacts 214b will be described later.

FIG. 2 is a diagram for explaining the focus mechanism. The focus lens barrel 204 has three cam followers 204a on the outer periphery, and the cam followers 204a are engaged with the cam grooves 203a of the focus cam ring 203. A focus key 102c fixed to the rotation ring 102 is engaged with a keyway 204b provided in a portion extending in the optical axis direction from the outer periphery of the focus lens barrel 204 so as to be movable in the optical axis direction. Thereby, when the rotation ring 102 is rotated by the drive of the motor unit 100, the rotational force is transmitted to the focus lens barrel 204 via the focus key 102c. Focus adjustment is performed by moving the focus lens barrel 204 toward the object side while rotating and moving the focus group Lf together with the focus lens barrel 204.

(About the configuration of the motor unit)
Next, the configuration of the motor unit 100 for moving the focus group Lf in the optical axis direction during focusing will be described. FIG. 3 is a sectional view of the structure around the motor unit 100, indicated by the broken line in FIG. In addition, in FIG. 3, the motor unit 100 and the rotating ring 102 are annular members around the optical axis.

The motor unit 100 is an ultrasonic motor, and by rotating the rotation ring 102, it indirectly moves the focus group Lf in the optical axis direction.

The motor unit 100 includes a rotor (mover) 104 and a stator (stator) 105. A piezoelectric element 106 is fixedly arranged with respect to the stator 105, and the piezoelectric element 106 vibrates based on instructions from a control board 214. As the piezoelectric element 106 vibrates, a portion 105a of the stator 105 that is in contact with the rotor 104 (hereinafter referred to as the contact portion 105a) moves in an elliptical manner, and the rotor 104, which is arranged so as to be in constant contact with the contact portion 105a, rotates. do.

The stator 105 is supported with respect to the fixed cylinder 101 via a piezoelectric element 106, a buffer member 107, and a buffer member 108. Further, the stator 105 is connected to a biasing member 111 via a buffer member 107, a metal ring 109, and a washer 110, and is biased by the biasing member 111 toward the rotor 104 with a predetermined pressing force. By shifting the position of the biasing member 111 in the optical axis direction, the pressing force applied to the stator 105 can be adjusted.

The rotating ring 102 is arranged around the outer periphery of the fixed cylinder 101, which is a cylindrical member fixed to the guide cylinder 201. A rubber ring 103 is fixed to the rotating ring 102, and a rotor 104 is fixed to the rubber ring 103. Therefore, as the rotor 104 rotates, the rubber ring 103 and the rotating ring 102 rotate integrally with the rotor 104. The rotating ring 102 is in contact with bearings 112 arranged at equal intervals in the circumferential direction via an end surface 102a, and is supported in the optical axis direction via the bearings 112 and screws 113. A sensor 118 detects a periodic pattern formed on a scale 117 disposed around the inner circumference of the rotating ring 102. Control board 214 controls motor unit 100 using the detection results. That is, the control board 214 controls the rotation angle and speed of the rotating ring 102 by controlling the drive of the motor unit 100, and further controls the moving direction and moving speed of the focus group Lf.

Next, a circuit configuration for driving the motor unit 100 will be described using FIGS. 4 and 5. FIG. 4 is a perspective view of the motor unit 100, with the rotating ring 102 and rotor 104 removed.

In FIG. 4, the drive board 301 is a voltage transformer including coils 302a to 302d, and in this embodiment, includes a booster circuit that boosts the voltage supplied (input) from the camera using the coils 302a to 302d. . Note that since the booster circuit is a general circuit, detailed explanation will be omitted. Then, the output voltage output from the booster circuit of the drive board 301 is supplied to the motor unit 100, and the motor unit 100 is driven using the output voltage.

The drive board 301 is arranged so as to be wrapped around the outer periphery of the fixed cylinder 101, and has flat parts 301a, 301b, 301c, and 301d (the flat part 301d is shown in FIG. 5) for mounting electronic components.

Further, a coil 302a is arranged on the plane part 301a, a coil 302b is arranged on the plane part 301b, a coil 302c is arranged on the plane part 301c, and a coil 302d is arranged on the plane part 301d. In this way, all of the coils 302a to 302d are not arranged in one plane part, but the coils 302a to 302d are arranged in a distributed manner in the circumferential direction (direction around the optical axis) of the optical system OL. Further, in order to enable such arrangement of the coils 302a to 302d, the flat portions 301a to 301d are composed of a plurality of surfaces that are non-parallel to each other. With such configurations of the flat portions 301a to 301d and the coils 302a to 302d, it is possible to suppress an increase in the outer diameter of the lens device 200. Note that the configurations of the flat portions 301a to 301d and the coils 302a to 302d are merely examples, and are not limited to the configuration shown in FIG. 4.

FIG. 5 is a perspective view of main parts showing the connection between the drive board 301 and the control board 214. In FIG. 5, only parts related to electrical connections are illustrated. The control board 214 controls the drive of the motor unit 100, electromagnetic aperture unit (not shown), and the like. The plane part 301a is connected to the stator 105 and the FPC board 305, the plane part 301c is connected to the control board 214 and the FPC board 304, and the plane part 301d is connected to the control board 214 and the FPC board 303. Power supplied from the camera through the electrical contacts 214b (shown in FIG. 1) arranged on the mount section 213 is supplied to the control board 214 through the FPC board 214a, and the remaining power is supplied through the FPC board 303. It is supplied to the drive board 301. Furthermore, drive commands transmitted from the camera via the electrical contacts 214b (shown in FIG. 1) and signals from the focus ring (not shown) are transmitted to the control circuit of the drive board 301 via the FPC board 304. . The voltage boosted by the booster circuit including the coils 302a to 302d is transmitted to the piezoelectric element 106 of the stator 105 via the output FPC board 305. The rotational position information of the rotating ring 102 detected by the sensor 118 is transmitted to the control board 214 via the FPC board 306 for feedback control of the rotating ring 102.

Next, a preferred arrangement of the drive board 301 including the coils 302a to 302d will be described.

The driving board 301 is configured such that the positions of the coils 302a to 302d are arranged in the range from the position of the most object-side surface of the optical system OL at the wide-angle end (the object-side surface of the most object-side lens of the first lens group L1) to the first lens group. It is arranged to be at a position away from the image side by more than the maximum movement amount of L1.

The first reason for this arrangement is that the first lens group L1 moves toward the object side during zooming from the wide-angle end to the telephoto end. This is because it is difficult to arrange 302d.

The second reason is to avoid increasing the outer diameter of the lens device 200. If the coils 302a to 302d are arranged on the side perpendicular to the optical axis than the holding member 221 and the linear cylinder 222 that moves integrally with the holding member 221, the outer diameter of the lens device 200 will increase. Therefore, the coils 302a to 302d are arranged closer to the image side than the holding member 221 and the rectilinear cylinder 222 that moves together. The linear cylinder 222, which moves integrally with the holding member 221 holding the first lens group L1, may require a length in the optical axis direction that is greater than the maximum movement amount of the first lens group L1 during zooming. many. Therefore, as described above, the positions of the coils 302a to 302d are specified using the position of the surface of the first lens group L1 closest to the object at the wide-angle end and the maximum movement amount. In this way, by shifting the positions of the coils 302a to 302d in the optical axis direction and the holding member 221 that holds the first lens group L1, which has the largest outer diameter in the lens device 200, the outer diameter of the lens device 200 can be increased. This reduces the size of the lens device 200.

Further, the drive board 301 is arranged such that the coils 302a to 302d are positioned closer to the object side than the most image side surface of the optical system OL at the wide-angle end. As a result, the coils 302a to 302d, which are sources of noise, can be placed away from the image plane IMG where the image sensor of the camera is arranged, and it is possible to reduce noise in the image signal acquired by the image sensor. A more preferable position of the coils 302a to 302d is a position away from the image plane IMG toward the object side by at least twice the back focus of the optical system OL at the wide-angle end. Here, the "back focus" is the distance on the optical axis from the final surface (the lens surface closest to the image side) of the optical system OL to the paraxial image surface expressed in air equivalent length.

Furthermore, it is preferable to arrange the drive board 301 so that the coils 302a to 302d are arranged within the outermost diameter range of the holding member 221 and the linearly moving cylinder 222 when viewed in the optical axis direction. Thereby, unnecessary increase in the outer diameter of the lens device 200 can be suppressed.

Furthermore, it is preferable that the drive board 301 be arranged near the second lens group L2. Specifically, it is preferable that the second lens group L2 and the drive board 301 at the wide-angle end are arranged such that at least a portion thereof overlaps when viewed in a direction perpendicular to the optical axis. Since the second lens group L2 is easy to optically configure to have a small outer diameter, the coils 302a to 302d can be placed away from the image plane IMG without increasing the outer diameter of the lens device 200.

In a large-diameter lens such as the optical system OL, the mass of the lens group that moves during focusing becomes large, and the motor unit 100 is required to have a force that generates high torque. Correspondingly, the coils 302a to 302d provided on the motor unit 100 and the drive board 301 tend to be larger. Therefore, in this embodiment, the drive board 301 and the motor unit 100 are arranged offset in the optical axis direction. This arrangement suppresses an increase in the outer diameter of the lens device 200. Furthermore, a drive board 301 is arranged on the object side of the motor unit 100. By arranging the drive substrate 301 as far away from the image plane IMG as possible, it is possible to reduce noise in the image signal acquired by the image sensor disposed on the image plane IMG.

Further, the drive board 301 and the motor unit 100 are arranged closer to the object than the control board 214. Thereby, the influence of the magnetic field generated from the coils 302a to 302d on the drive board 301 can be reduced, and the influence of vibrations generated in the motor unit 100 on the image signal acquired by the image sensor can be reduced. Note that a configuration may be adopted in which the drive board 301 is arranged on the object side of the control board 214 and the motor unit 100 is arranged on the image side of the control board 214.

Further, it is preferable that the coils 302a to 302d are disposed offset from at least one of the straight groove 201a and the cam groove 203a. Here, being deviated means that the coils 302a to 302d do not overlap with at least one of the linear groove 201a and the cam groove 203a when viewed in a direction perpendicular to the optical axis. This suppresses the magnetic field generated from the coils 302a to 302d from entering the inside of the guide tube 201 via the straight groove 201a and the cam groove 203a, and reduces noise in the image signal acquired by the image sensor. Can be done.

In addition, although the case where the focus group Lf is the second lens group L2 has been described as an example, the configuration of the focus group Lf is not limited to this.

Moreover, although the case where the motor unit 100 is an ultrasonic motor has been described as an example, the specific configuration of the motor unit 100 is not limited to this as long as it is a means that can move the focus group Lf. Further, although the case where the coils 302a to 302d are used in a booster circuit has been described as an example, the present invention is not limited to this. The drive board 301 only needs to have a function as a voltage transformer, and for example, if desired in relation to the motor unit 100, the coils 302a to 302d may be used in a voltage step-down circuit.

(Regarding the preferred configuration of the optical system)
Next, the configuration of a suitable optical system OL in the lens device 200 of the embodiment will be described.

As described above, the optical system OL of the present invention includes a plurality of lens groups in which the distance between adjacent lens groups changes during zooming. The plurality of lens groups are arranged in order from the object side to the image side, including a first lens group L1 having a positive refractive power, a second lens group L2 having a negative refractive power, and a rear lens group having an overall positive refractive power. Consists of group LR. In particular, when zooming from the wide-angle end to the telephoto end, a high zoom ratio is achieved by moving the first lens group L1 toward the object side.

Furthermore, when focusing from an object at infinity to a near object, it is preferable that the second lens group L2 moves toward the object side. Thereby, even when the aperture of the optical system OL is increased, good optical performance can be achieved over the entire focus range while reducing fluctuations in coma aberration and lateral chromatic aberration during focusing.

Further, it is preferable that the optical system OL satisfies at least one of the following conditional expressions (1) to (5). Thereby, it is possible to obtain at least one of the following effects: high optical performance of the optical system OL, miniaturization of the lens device 200, and reduction of noise in the image signal acquired by the image sensor.

When the amount of movement of the first lens group L1 during zooming from the wide-angle end to the telephoto end is M1, and the focal length of the optical system OL at the wide-angle end is fw, it is preferable to satisfy conditional expression (1).
0.5<|M1|/fw<1.3...(1)

Conditional expression (1) defines a preferable range of movement amount of the first lens group L1. If the lower limit of conditional expression (1) is exceeded and the amount of movement of the first lens group L1 becomes small, it becomes difficult to ensure the zoom ratio, which is not preferable. When the upper limit of conditional expression (1) is exceeded and the amount of movement of the first lens group L1 increases, the holding member 221 and the linear cylinder 222 become longer in the optical axis direction in accordance with the amount of movement of the first lens group L1. Therefore, the coils 302a to 302d are arranged close to the image plane IMG, which is not preferable because it becomes difficult to reduce noise in the image signal acquired by the image sensor.

When the effective diameter of the surface closest to the object side of the first lens group L1 is B1obj_ea, and the effective diameter of the surface closest to the image side of the second lens group L2 is B2img_ea, it is preferable that conditional expression (2) is satisfied. However, in this specification, the effective diameter refers to the diameter on the lens surface of the light ray that passes through the position farthest from the optical axis among the light rays that pass through the lens surface.
1.5<B1obj_ea/B2img_ea<3.0...(2)

Conditional expression (2) defines the ratio between the effective diameter of the lens closest to the object side of the first lens group L1 and the effective diameter of the lens closest to the image side of the second lens group L2.

The outer diameter of the optical system OL tends to be determined by the outer diameter of the first lens group L1. Furthermore, when the coils 302a to 302d are arranged at positions that satisfy the above-mentioned configuration, the coils 302a to 302d are arranged by the first lens group L1 and the second lens group L2 having a smaller outer diameter than the first lens group L1. It can be placed in the space formed. Therefore, when the lower limit of conditional expression (2) is exceeded and the effective diameter of the surface closest to the image side of the second lens group becomes large, it is difficult to arrange the coils 302a to 302d while making the lens device 200 compact. This is not desirable because it becomes If the upper limit of conditional expression (2) is exceeded, the effective diameter of the surface closest to the object side of the first lens group L1 becomes large, and the outer diameter of the lens device 200 becomes large, which is not preferable.

Among the lens groups composing the rear group LR, the lens group disposed closest to the object side is the third lens group L3, and among the effective diameters of the lenses composing the third lens group L3, the effective diameter of the largest lens is B3max_ea, and the focal length of the optical system OL at the wide-angle end is fw. At this time, it is preferable that conditional expression (3) is satisfied.
1.0<B3max_ea/fw<2.0...(3)

Conditional expression (3) defines the ratio between the effective diameter of the largest lens among the effective diameters of the lenses constituting the third lens group L3 and the focal length of the optical system OL at the wide-angle end. If the maximum effective diameter of the third lens group L3 becomes smaller than the lower limit of conditional expression (3), it becomes difficult to both secure a sufficiently bright open F-number at the telephoto end and achieve a high zoom ratio. Therefore, it is undesirable. If the maximum effective diameter of the third lens group L3 becomes larger than the upper limit of conditional expression (3), the outer diameter of the lens device 200 becomes large when the coils 302a to 302d are arranged, which is not preferable.

When the back focus of the optical system OL at the wide-angle end is skw, and the focal length of the optical system OL at the wide-angle end is fw, it is preferable that conditional expression (4) is satisfied.
0.3<skw/fw<1.1 (4)

Conditional expression (4) indicates the ratio between the back focus and the focal length of the optical system at the wide-angle end. When the back focus becomes short by falling below the lower limit of conditional expression (4), the coils 302a to 302d are arranged relatively close to the image plane IMG. This is not preferable because it becomes difficult to reduce noise in the image signal acquired by the image sensor. Furthermore, it is undesirable because the lens disposed closest to the image side may interfere with the shutter mechanism of the camera or cause strong ghosts to occur. When the back focus becomes longer than the upper limit of conditional expression (4), it becomes necessary for the optical system OL to have a retrofocus configuration. This is not preferable because it becomes difficult to correct distortion and the like.

The distance on the optical axis from the surface closest to the object side of the second lens group L2 to the surface closest to the image side of the second lens group L2 is T2, and the distance on the optical axis from the surface closest to the object side of the second lens group L2 is T2. Let To be the distance on the optical axis from the surface of the final lens group closest to the object side to the surface of the final lens group closest to the image side. At this time, it is preferable that conditional expression (5) be satisfied.
0.3<T2/To<1.0...(5)

Conditional expression (5) defines the ratio of the lengths of the second lens group L2 and the final lens group in the optical axis direction. If the lower limit of conditional expression (5) is exceeded and the final lens group becomes longer in the optical axis direction, the diameter of the lens placed closest to the image side of the optical system OL may become larger, or the rays within the second lens group L2 may become longer. This is not preferable because the change in height cannot be taken sufficiently, making it difficult to correct curvature of field and the like. If the second lens group L2 becomes longer in the optical axis direction by exceeding the upper limit of conditional expression (5), it is not preferable because the diameter of the lens disposed closest to the object side of the optical system OL becomes large. Furthermore, when the second lens group moves during focusing, it becomes difficult to perform quick focusing, which is not preferable.

Note that it is more preferable to set the numerical ranges of conditional expressions (1) to (5) as follows.
0.7<|M1|/fw<1.1...(1a)
2.0<B1obj_ea/B2img_ea<2.8...(2a)
1.2<B3max_ea/fw<1.5...(3a)
0.5<skw/fw<1.0...(4a)
0.7<T2/To<0.95...(5a)

Next, preferred embodiments of the optical system OL will be described using FIGS. 6 to 17. In the cross-sectional views of the optical system OL shown in FIGS. 6, 8, 10, 12, 14, and 16, the image plane IMG corresponds to the arrangement position of the image sensor in the camera.

The aberration diagrams shown in FIGS. 7, 9, 11, 13, 15, and 17 are, from left to right, a spherical aberration diagram, an astigmatism diagram, a distortion aberration diagram, and a chromatic aberration diagram. The solid line of spherical aberration indicates the d-line (wavelength 587.6 nm) of the Fraunhofer line, and the dashed-two dotted line indicates the g-line (wavelength 435.8 nm). The solid line ΔS in the astigmatism diagram shows the sagittal ray, the broken line ΔM shows the meridional ray, the solid line in the distortion diagram shows the d-line, and the two-dot chain line in the chromatic aberration diagram shows the g-line.

The optical system OL of Examples 1 to 3 will be explained. FIG. 6 is a cross-sectional view of the optical system OL of Example 1 at the wide-angle end. FIG. 7(a) is an aberration diagram at the wide-angle end when focusing on an object at infinity, FIG. 7(b) is an aberration diagram at an intermediate position when focusing on an object at infinity, and FIG. ) is an aberration diagram at the telephoto end when focusing on an object at infinity.

FIG. 8 is a cross-sectional view of the optical system OL of Example 2 at the wide-angle end. FIG. 9(a) is an aberration diagram at the wide-angle end when focusing on an object at infinity, FIG. 9(b) is an aberration diagram at an intermediate position when focusing on an object at infinity, and FIG. ) is an aberration diagram at the telephoto end when focusing on an object at infinity.

FIG. 10 is a cross-sectional view of the optical system OL of Example 3 at the wide-angle end. FIG. 11(a) is an aberration diagram at the wide-angle end when focusing on an object at infinity, FIG. 11(b) is an aberration diagram at an intermediate position when focusing on an object at infinity, and FIG. ) is an aberration diagram at the telephoto end when focusing on an object at infinity.

The optical system OL of Examples 1 to 3 includes a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, and a second lens group L2 with positive refractive power, which are arranged in order from the object side to the image side. It consists of three lens groups L3 and a fourth lens group L4 with positive refractive power. That is, the rear group LR having positive refractive power over the entire zoom range is composed of the third lens group L3 and the fourth lens group L4.

In the optical systems OL of Examples 1 to 3, when zooming from the wide-angle end to the telephoto end, the first lens group L1 moves to the object side, the second lens group L2 moves to the image side, and then moves to the object side. , the third lens group L3 and the fourth lens group L4 move toward the object side. When focusing from an object at infinity to an object at a short distance, the second lens group L2 moves toward the object side.

The optical systems of Examples 1 to 3 differ from each other in the number of lenses in each lens group, and the refractive index and shape of the lenses constituting the optical system OL.

Next, the optical system OL of Example 4 will be explained. FIG. 12 is a cross-sectional view of the optical system OL of Example 4 at the wide-angle end. FIG. 13(a) is an aberration diagram at the wide-angle end when focusing on an object at infinity, FIG. 13(b) is an aberration diagram at an intermediate position when focusing on an object at infinity, and FIG. ) is an aberration diagram at the telephoto end when focusing on an object at infinity.

The optical system OL of Example 4 includes a first lens group L1 with a positive refractive power, a second lens group L2 with a negative refractive power, and a third lens with a positive refractive power, which are arranged in order from the object side to the image side. Consists of group L3. That is, the rear group LR having positive refractive power over the entire zoom range is composed of the third lens group L3.

When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves to the object side, the second lens group L2 moves to the image side and then to the object side, and the third lens group L3 moves to the object side. do. When focusing from an object at infinity to an object at a short distance, the second lens group L2 moves toward the object side.

Next, the optical system OL of Example 5 will be explained. FIG. 14 is a cross-sectional view of the optical system OL of Example 5 at the wide-angle end. FIG. 15(a) is an aberration diagram at the wide-angle end when focusing on an object at infinity, FIG. 15(b) is an aberration diagram at an intermediate position when focusing on an object at infinity, and FIG. ) is an aberration diagram at the telephoto end when focusing on an object at infinity.

The optical system OL of Example 5 includes a first lens group L1 with a positive refractive power, a second lens group L2 with a negative refractive power, and a third lens with a positive refractive power, which are arranged in order from the object side to the image side. It consists of a lens group L3, a fourth lens group L4 with positive refractive power, and a fifth lens group L5 with positive refractive power. That is, the rear group LR having positive refractive power over the entire zoom range is composed of the third lens group L3, the fourth lens group L4, and the fifth lens group L5.

During zooming from the wide-angle end to the telephoto end, the first lens group L1 moves to the object side, the second lens group L2 moves to the image side and then to the object side, and the third lens group L3 and fourth lens group L4 and the fifth lens group L5 move toward the object side. When focusing from an object at infinity to an object at a short distance, the second lens group L2 moves toward the object side.

Embodiments of the present invention are not limited to so-called positive lead zoom lenses in which the lens group closest to the object side has positive refractive power, but also to so-called negative lead zoom lenses in which the lens group closest to the object side has negative refractive power. It can also be applied to lenses. The optical system OL of Example 6 will be described below as a negative lead zoom lens.

FIG. 16 is a cross-sectional view of the optical system OL of Example 6 at the wide-angle end. FIG. 17(a) is an aberration diagram at the wide-angle end when focusing on an object at infinity, FIG. 17(b) is an aberration diagram at an intermediate position when focusing on an object at infinity, and FIG. ) is an aberration diagram at the telephoto end when focusing on an object at infinity.

The optical system OL of Example 6 includes a first lens group L1 with a negative refractive power, a second lens group L2 with a positive refractive power, and a third lens with a negative refractive power, which are arranged in order from the object side to the image side. It consists of a lens group L3, a fourth lens group L4 with positive refractive power, a fifth lens group L5 with negative refractive power, and a sixth lens group L6 with positive refractive power. The second lens group L2 to the sixth lens group L6 are a rear group LR having positive refractive power as a whole.

During zooming from the wide-angle end to the telephoto end, the first lens group L1 moves to the image side and then moves to the object side, and the second lens group L2, third lens group L3, fourth lens group L4, and fifth lens group L5 and the sixth lens group L6 move toward the object side. When focusing from an object at infinity to an object at a short distance, the third lens group L3 moves toward the object side.

FIG. 18(a) is a diagram showing the configuration of the lens device 300 of the second embodiment at the wide-angle end, and FIG. 18(b) is a diagram showing the configuration of the lens device 300 at the telephoto end. The optical system OL is a negative lead type zoom lens. In the lens device 300, the fixed tube 501, the mount section 502, the guide tube 503, and the cam ring 504 have the same structural functions as the fixed tube 101, the mount section 213, the guide tube 201, and the cam ring 202 of the lens device 200, respectively.

The holding member 511 holds the first lens group L1 and moves in the optical axis direction together with the first lens group L1. The holding member 512 integrally holds the rear group LR. The holding member 513 holds the third lens group, which is the focus lens group, and the holding member 515 holds the fifth lens group. In response to the rotation of the cam ring 504, the holding member 511, the holding member 512, and the holding member 515 move in the optical axis direction, thereby performing zooming. The first lens group L1 moves by a distance L during zooming from the wide-angle end to the telephoto end.

The motor unit 516, drive board 517, and control board 518 have the same functions as the motor unit 100, drive board 301, and control board 214 of the lens device 200, respectively. That is, the drive board 517 is a voltage boosting means that includes a plurality of coils that boosts the voltage supplied to the motor unit 516. In FIG. 18, one coil among the plurality of coils is illustrated as coil 517a. The detailed driving principle of the motor unit 516 is almost the same as that in the first embodiment, so a detailed explanation will be omitted.

Even in the optical system OL consisting of the first lens group L1 having a negative refractive power and the rear group LR having a positive refractive power as a whole, the mass of the lens group that moves during focusing increases, generating high torque in the motor unit 516. force is likely to be required. Accordingly, the motor unit 516 and drive board 517 tend to become larger.

In this embodiment, as in the first embodiment, the drive board 517 and the motor unit 516 are arranged offset in the optical axis direction. Thereby, an increase in the outer diameter of the lens device 300 can be suppressed. Further, a drive board 517 is arranged on the object side of the motor unit 100. By arranging the drive board 517 as far away from the image plane IMG as possible, it is possible to reduce the occurrence of noise in the image signal acquired by the image sensor disposed on the image plane IMG. Note that the drive board 517 may be arranged on the object side of the control board 518, and the motor unit 516 may be arranged on the image side of the control board 518.

The drive board 517 is arranged such that the position of the coil 517a is from the position of the most object-side surface of the optical system OL at the wide-angle end (the object-side surface of the most object-side lens of the first lens group L1) to the position of the first lens group L1. It is arranged so as to be at a position away from the image side by more than the maximum movement amount. The reason is as explained in the first embodiment.

Further, it is preferable that the drive board 517 is arranged such that the coil 517a is positioned closer to the object than the most image-side surface of the optical system OL at the wide-angle end. More preferably, the coil 517a is located at a position that is at least twice as far away from the image plane IMG toward the object side as the back focus of the optical system OL at the wide-angle end.

Furthermore, it is preferable to arrange the drive board 517 so that the coil 517a is arranged within the range of the outermost diameter of the holding member 511 and the linear cylinder when viewed in the optical axis direction. Thereby, unnecessary increase in the outer diameter of the lens device 300 can be suppressed.

Further, it is preferable that the drive board 517 is arranged near the second lens group L2. Specifically, it is preferable that the second lens group L2 and the drive board 517 at the wide-angle end are arranged such that at least a portion thereof overlaps when viewed in a direction perpendicular to the optical axis. Thereby, the coil 517a can be placed away from the image plane IMG without increasing the outer diameter of the lens device 300.

Furthermore, it is preferable that the coil 517a is disposed offset from at least one of the linear groove and the cam groove of the lens device 300. Thereby, noise in the image signal acquired by the image sensor can be reduced.

In addition, although the case where the focus group Lf is the third lens group L3 has been described as an example, the configuration of the focus group Lf is not limited to this.

Moreover, although the case where the motor unit 516 is an ultrasonic motor has been described as an example, the specific configuration of the motor unit 516 is not limited to this as long as it is a means that can move the focus group Lf. Furthermore, the drive board 517 only needs to have a function as a voltage transformer, and for example, if desired in relation to the motor unit 516, the coil may be used in a voltage step-down circuit.

Also in this embodiment, the lens device 300 further satisfies the above-mentioned conditional expressions (1) to (4). Thereby, each of the above-mentioned effects can be obtained.

Numerical examples corresponding to the optical system OL of Examples 1 to 6 are shown in [Numerical Example 1] to [Numerical Example 6]. In each numerical example, the surface number indicates the order of the optical surfaces from the object side. r is the radius of curvature of the optical surface (mm), d is the distance between adjacent optical surfaces (mm), nd is the refractive index of the material of the optical member at the d-line, and νd is the Abbe's value of the material of the optical member with respect to the d-line. Show the number. When the refractive index of the material for the Fraunhofer line F line (486.1 nm), d line (587.6 nm), and C line (656.3 nm) is respectively Ng, NF, Nd, and NC, the Abbe number νd is,
νd=(Nd-1)/(NF-NC)
Expressed as A portion where the interval d is (variable) indicates that the interval changes during zooming. The distance d at typical zoom positions is separately described.

BF indicates back focus. The "back focus" is as described above, and the "total lens length" is the distance on the optical axis from the frontmost surface (lens surface closest to the object) of the optical system OL to the final surface plus the back focus. be.

Aspherical surfaces are marked with * to the right of the surface number in each numerical example. For the aspherical shape, the optical axis direction is the X axis, the direction perpendicular to the optical axis is the H axis, the traveling direction of the light is positive, R is the paraxial radius of curvature, K is the conic constant, and A4, A6, A8, A10, and A12 are respectively When the aspheric coefficient is

It is expressed as The aspherical coefficient "e±x" means 10 ^±x .

Furthermore, values corresponding to conditional expressions (1) to (5) in each of [Numerical Example 1] to [Numerical Example 6] are shown in [Table 1].

[Numerical Example 1]
Unit: mm
Surface data Surface number rd nd vd Effective diameter
1 153.129 2.10 1.80810 22.8 77.37
2 68.126 9.20 1.72916 54.7 72.90
3 229.651 0.15 72.09
4 56.538 8.42 1.77250 49.6 66.23
5 143.922 (variable) 64.80
6* 177.309 1.50 1.85135 40.1 39.40
7 21.050 9.92 29.85
8 -48.645 0.90 1.76385 48.5 27.55
9 25.647 8.34 1.85478 24.8 25.49
10 -50.942 2.34 26.71
11 -31.481 5.59 1.51742 52.4 26.99
12 -18.463 1.20 1.88300 40.8 28.04
13* -44.498 (variable) 31.63
14(Aperture) ∞ 0.30 35.48
15 65.756 4.12 1.72916 54.7 37.69
16 371.024 0.15 37.92
17 45.665 9.76 1.80400 46.6 39.09
18* -76.624 3.63 38.26
19 -51.901 1.50 1.73800 32.3 35.75
20 27.845 8.48 1.49700 81.5 34.23
21 510.252 (variable) 34.47
22 39.711 7.32 1.43875 94.7 35.21
23 -174.360 0.15 34.76
24 37.228 7.09 1.59522 67.7 32.96
25 -104.496 0.30 32.54
26 87.786 1.10 1.69895 30.1 30.89
27 31.012 5.54 29.28
28* -1000.000 2.00 1.85400 40.4 29.24
29* 55.807 1.31 30.31
30 57.476 1.20 1.48749 70.2 32.34
31 35.136 5.66 1.85025 30.1 33.65
32 172.397 (variable) 33.86
Image plane ∞
Aspheric data 6th surface
K = 0.00000e+000 A 4= 5.10348e-006 A 6=-4.34457e-009 A 8= 1.37999e-011 A10=-2.48862e-014 A12= 2.63278e-017

Page 13
K = 0.00000e+000 A 4=-1.62945e-006 A 6=-1.93301e-009 A 8=-6.21737e-012 A10= 2.66590e-014 A12=-4.35899e-017

Page 18
K = 0.00000e+000 A 4= 2.55792e-006 A 6=-1.69292e-009 A 8=-2.27540e-012 A10= 4.02496e-015 A12=-2.17151e-018

Page 28
K = 0.00000e+000 A 4=-4.41081e-005 A 6= 1.28044e-007 A 8=-2.10057e-010 A10=-1.84393e-013 A12= 8.43712e-016

Page 29
K = 0.00000e+000 A 4=-3.09220e-005 A 6= 1.56402e-007 A 8=-2.84790e-010 A10= 1.76646e-013 A12= 2.07899e-016

Various data Zoom ratio 2.35
Wide Angle Intermediate Telephoto Focal Length 28.90 42.99 67.90
F number 2.05 2.05 2.06
Half angle of view (degrees) 36.82 26.72 17.67
Image height 21.64 21.64 21.64
Lens total length 163.98 171.82 184.65
BF 27.79 35.08 42.63

d 5 4.20 15.98 29.54
d13 16.62 8.94 2.27
d21 6.11 2.56 0.95
d32 27.79 35.08 42.63

Zoom lens group data group Starting plane Focal length
1 1 105.64
2 6 -19.62
3 14 53.91
4 22 48.64

[Numerical Example 2]
Unit: mm
Surface data Surface number rd nd vd Effective diameter
1 149.047 2.10 1.80810 22.8 77.63
2 68.781 8.93 1.72916 54.7 72.67
3 223.676 0.15 71.87
4 58.980 8.28 1.77250 49.6 66.39
5 159.657 (variable) 65.01
6* 176.499 1.50 1.76902 49.3 40.92
7 20.208 9.19 30.20
8 -63.499 0.90 1.76385 48.5 29.27
9 24.792 8.37 1.85478 24.8 26.74
10 -55.595 1.57 25.71
11 -41.903 5.18 1.48749 70.2 25.91
12 -19.594 1.20 1.88300 40.8 26.61
13* -74.922 (variable) 29.60
14(Aperture) ∞ 0.30 32.51
15 64.431 4.46 1.72916 54.7 34.49
16 ∞ 0.15 34.82
17 40.646 8.99 1.80400 46.6 35.97
18* -88.160 4.14 35.05
19 -47.780 1.50 1.73800 32.3 32.29
20 25.016 7.71 1.49700 81.5 30.89
21 248.460 (variable) 31.13
22 33.078 6.71 1.43875 94.7 31.98
23 -469.348 0.15 31.50
24 40.254 6.46 1.59522 67.7 32.14
25 -101.746 0.30 31.78
26 59.526 4.51 1.49700 81.5 30.01
27 -177.956 1.00 1.80610 33.3 28.99
28 44.079 4.23 27.51
29* -1000.000 3.00 1.85400 40.4 27.41
30* 109.178 3.26 28.71
31 -45.198 1.20 1.48749 70.2 29.04
32 45.131 6.42 2.00100 29.1 34.58
33 -169.151 (variable) 35.20
Image plane ∞
Aspheric data 6th surface
K = 0.00000e+000 A 4= 4.40628e-006 A 6=-2.80374e-009 A 8= 3.12113e-012 A10= 2.43107e-015 A12=-2.17038e-018

Page 13
K = 0.00000e+000 A 4=-2.36140e-006 A 6=-1.08356e-009 A 8=-1.99552e-011 A10= 1.00829e-013 A12=-1.77388e-016

Page 18
K = 0.00000e+000 A 4= 2.15576e-006 A 6=-2.33619e-009 A 8=-1.82040e-012 A10=-1.99976e-016 A12= 4.53234e-018

Page 29
K = 0.00000e+000 A 4=-4.82313e-005 A 6= 1.54634e-008 A 8= 3.00393e-010 A10=-1.04531e-012 A12= 1.51938e-015

Page 30
K = 0.00000e+000 A 4=-2.82244e-005 A 6= 5.87972e-008 A 8= 2.35247e-010 A10=-8.07024e-013 A12= 9.56680e-016

Various data Zoom ratio 2.35
Wide Angle Intermediate Telephoto Focal Length 28.91 42.97 67.89
F number 2.05 2.05 2.06
Half angle of view (degrees) 36.81 26.72 17.68
Image height 21.64 21.64 21.64
Lens total length 155.86 165.41 178.09
BF 19.57 25.90 33.38

d 5 3.86 16.61 29.64
d13 14.92 8.44 2.27
d21 5.66 2.61 0.95
d33 19.57 25.90 33.38

Zoom lens group data group Starting plane Focal length
1 1 105.82
2 6 -18.96
3 14 48.62
4 22 41.98

[Numerical Example 3]
Unit: mm
Surface data Surface number rd nd vd Effective diameter
1 185.690 2.10 1.89286 20.4 70.03
2 102.616 5.96 1.59522 67.7 67.25
3 506.983 0.15 66.40
4 60.547 6.61 1.76385 48.5 60.07
5 145.490 (variable) 58.57
6* 196.972 1.40 1.88300 40.8 38.96
7 23.897 8.29 31.23
8 -66.605 1.10 1.59282 68.6 30.42
9 27.915 4.65 1.90366 31.3 28.59
10 94.203 0.50 28.91
11 115.549 8.99 1.72825 28.5 29.11
12 -23.106 1.10 1.88300 40.8 29.78
13 -77.496 3.91 31.56
14 -25.285 1.20 1.95375 32.3 31.56
15 -39.935 (variable) 34.13
16(Aperture) ∞ 0.30 38.87
17 57.217 5.76 1.80400 46.6 42.54
18 -14821.675 0.15 42.60
19 48.154 8.94 1.77250 49.5 42.92
20* -101.713 5.94 42.12
21 -56.728 1.40 1.85025 30.1 37.21
22 29.702 7.73 1.49700 81.5 35.67
23 318.842 (variable) 36.07
24 46.088 5.77 1.49700 81.5 37.51
25 -2453.348 0.15 37.36
26 44.616 6.25 1.59522 67.7 36.94
27 -342.571 0.25 36.79
28 40.473 1.40 2.00100 29.1 35.76
29 33.629 9.25 1.49700 81.5 34.58
30 -70.003 0.15 33.63
31* 180.669 1.40 1.85400 40.4 31.91
32 24.228 3.96 1.48749 70.2 30.02
33 38.371 6.68 30.09
34 -35.992 1.40 1.59522 67.7 30.23
35 42.748 6.75 2.00069 25.5 36.02
36 -218.385 (variable) 36.59
Image plane ∞
Aspheric data 6th surface
K = 0.00000e+000 A 4= 4.39158e-006 A 6=-9.82898e-010 A 8= 2.69004e-012 A10=-1.15093e-015 A12= 6.67612e-018

Page 20
K = 0.00000e+000 A 4= 2.99070e-006 A 6=-2.29872e-009 A 8=-1.18958e-012 A10= 3.78487e-015 A12=-2.25763e-018

Page 31
K = 0.00000e+000 A 4=-1.47587e-005 A 6=-1.30088e-008 A 8= 2.79729e-011 A10=-7.52442e-014 A12= 1.40883e-016

Various data Zoom ratio 2.70
Wide Angle Intermediate Telephoto Focal Length 28.84 44.96 77.80
F number 2.06 2.06 2.06
Half angle of view (degrees) 36.87 25.70 15.54
Image height 21.64 21.64 21.64
Lens total length 162.79 173.70 191.92
BF 15.28 23.29 33.80

d 5 3.47 18.39 35.68
d15 16.63 8.99 1.85
d23 7.83 3.44 1.00
d36 15.28 23.29 33.80

Zoom lens group data group Starting plane Focal length
1 1 120.53
2 6 -20.85
3 16 52.49
4 24 40.08

[Numerical Example 4]
Unit: mm
Surface number rd nd vd Effective diameter
1 150.854 2.10 1.80810 22.8 80.04
2 67.631 9.20 1.72916 54.7 72.45
3 234.942 0.15 71.01
4 55.670 8.42 1.77250 49.6 59.72
5 166.444 (variable) 56.37
6* 141.978 1.50 1.85135 40.1 44.03
7 21.106 9.92 31.77
8 -47.855 0.90 1.76385 48.5 31.77
9 26.216 8.34 1.85478 24.8 28.81
10 -52.510 2.34 27.92
11 -31.512 5.59 1.51742 52.4 27.23
12 -18.748 1.20 1.88300 40.8 28.33
13* -42.199 (variable) 31.78
14(Aperture) ∞ 0.30 35.42
15 57.610 4.12 1.72916 54.7 37.80
16 181.689 0.15 37.91
17 39.841 9.76 1.80400 46.6 39.02
18* -112.072 3.63 37.86
19 -76.051 1.50 1.73800 32.3 35.10
20 22.014 8.48 1.49700 81.5 32.24
21 77.733 9.98 32.28
22 41.069 7.32 1.43875 94.7 35.15
23 -155.403 0.15 34.83
24 32.330 7.09 1.59522 67.7 34.40
25 -190.252 0.30 34.03
26 78.705 1.10 1.69895 30.1 32.53
27 29.270 6.20 30.82
28* ∞ 2.00 1.85400 40.4 30.84
29* 72.196 0.50 32.16
30 49.371 1.20 1.48749 70.2 34.85
31 34.914 5.66 1.85025 30.1 35.73
32 105.610 (variable) 35.71
Image plane ∞

Aspheric data 6th surface
K = 0.00000e+000 A 4= 4.40847e-006 A 6=-6.65502e-009 A 8= 2.33218e-011 A10=-4.27753e-014 A12= 3.97452e-017

Page 13
K = 0.00000e+000 A 4=-1.89550e-006 A 6=-1.66337e-009 A 8=-5.39284e-012 A10= 9.54074e-015 A12= 2.00846e-018

Page 18
K = 0.00000e+000 A 4= 3.02728e-006 A 6=-3.04809e-009 A 8= 1.61555e-012 A10=-6.28747e-015 A12= 8.01506e-018

Page 28
K = 0.00000e+000 A 4=-5.48184e-005 A 6= 1.47546e-007 A 8=-1.54308e-010 A10= 5.34243e-015 A12= 3.31189e-017

Page 29
K = 0.00000e+000 A 4=-4.52422e-005 A 6= 1.72898e-007 A 8=-2.36785e-010 A10= 1.82207e-013 A12=-7.90015e-017

Various data Zoom ratio 2.10
Wide Angle Intermediate Telephoto Focal Length 29.50 55.96 62.01
F number 2.05 2.05 2.05
Half angle of view (degrees) 36.26 21.14 19.23
Image height 21.64 21.64 21.64
Lens total length 170.24 182.90 186.28
BF 27.86 44.59 45.27

d 5 3.30 15.88 19.84
d13 19.97 3.33 2.06
d32 27.86 44.59 45.27

Zoom lens group data group Starting plane Focal length
1 1 95.47
2 6 -20.79
3 14 38.89

[Numerical Example 5]
Unit: mm
Surface data Surface number rd nd vd Effective diameter
1 155.037 2.10 1.80810 22.8 81.70
2 70.116 9.20 1.72916 54.7 76.52
3 195.501 0.15 75.57
4 57.008 8.42 1.77250 49.6 69.08
5 142.617 (variable) 68.11
6* 214.923 1.50 1.85135 40.1 40.56
7 21.096 9.92 30.15
8 -47.358 0.90 1.76385 48.5 27.97
9 25.320 8.34 1.85478 24.8 25.67
10 -50.621 2.34 25.15
11 -29.869 5.59 1.51742 52.4 25.45
12 -18.475 1.20 1.88300 40.8 26.78
13* -41.822 (variable) 29.88
14(Aperture) ∞ 0.30 33.57
15 66.026 4.12 1.72916 54.7 35.48
16 364.260 0.15 35.76
17 45.771 9.76 1.80400 46.6 36.84
18* -76.427 3.63 35.94
19 -51.795 1.50 1.73800 32.3 33.65
20 27.337 8.48 1.49700 81.5 32.48
21 627.170 (variable) 32.81
22 39.190 7.32 1.43875 94.7 33.59
23 -169.944 0.15 33.12
24 35.976 7.09 1.59522 67.7 33.59
25 -105.493 0.30 33.23
26 87.336 1.10 1.69895 30.1 31.45
27 30.956 5.54 29.74
28* -979.971 2.00 1.85400 40.4 29.70
29* 60.597 (variable) 30.74
30 58.679 1.20 1.48749 70.2 33.01
31 36.321 5.66 1.85025 30.1 34.26
32 171.275 (variable) 34.47
Image plane ∞

Aspheric data 6th surface
K = 0.00000e+000 A 4= 5.33975e-006 A 6=-4.16853e-009 A 8= 1.20950e-011 A10=-2.07542e-014 A12= 2.33792e-017

Page 13
K = 0.00000e+000 A 4=-1.42782e-006 A 6=-2.17995e-009 A 8=-3.88250e-012 A10= 2.49763e-014 A12=-4.87268e-017

Side 18
K = 0.00000e+000 A 4= 2.64561e-006 A 6=-1.91946e-009 A 8=-2.05520e-012 A10= 3.81185e-015 A12=-1.75514e-018

Page 28
K = 0.00000e+000 A 4=-4.42649e-005 A 6= 1.28218e-007 A 8=-2.04999e-010 A10=-1.48969e-013 A12= 7.20523e-016

Page 29
K = 0.00000e+000 A 4=-3.10150e-005 A 6= 1.57698e-007 A 8=-2.81303e-010 A10= 1.78277e-013 A12= 1.99011e-016

Various data Zoom ratio 2.19
Wide Angle Intermediate Telephoto Focal Length 26.96 38.38 59.03
F number 2.05 2.05 2.06
Half angle of view (degrees) 38.75 29.41 20.13
Image height 21.64 21.64 21.64
Lens total length 162.55 169.75 183.06
BF 26.37 32.98 40.70

d 5 4.84 15.74 29.53
d13 16.11 8.89 2.40
d21 5.83 2.61 0.98
d29 1.45 1.57 1.48
d32 26.37 32.98 40.70

Zoom lens group data group Starting plane Focal length
1 1 114.61
2 6 -19.54
3 14 54.33
4 22 75.16
5 30 73.67

[Numerical Example 6]
Unit: mm
Surface data Surface number rd nd vd Effective diameter
1 30.000 1.60 1.77250 49.6 37.45
2 18.850 4.50 31.64
3* 26.555 2.50 1.53110 55.9 31.50
4* 22.754 4.00 29.33
5 -586.400 1.25 1.69680 55.5 29.45
6 21.473 0.50 26.46
7 21.403 4.50 1.80810 22.8 26.58
8 43.781 (variable) 25.57
9* 113.037 2.00 1.53110 55.9 13.30
10 -62.214 (variable) 13.30
11 -25.577 1.00 1.53110 55.9 12.10
12* 69.090 (variable) 12.48
13 3436.015 2.00 1.53110 55.9 13.25
14* -32.138 0.15 13.56
15 24.000 4.00 1.60311 60.6 13.96
16 -23.373 0.75 1.84666 23.9 13.86
17 -53.850 1.00 13.91
18 (aperture) ∞ (variable) 13.68
19 -775.077 0.60 1.58144 40.8 12.14
20 13.120 2.10 1.80610 33.3 11.79
21 23.477 1.00 11.40
22 ∞ (variable) 11.37
23 1993.370 1.70 1.53110 55.9 16.20
24* 129.782 0.90 16.95
25 39.224 3.30 1.48749 70.2 18.09
26 -43.398 (variable) 18.47
Image plane ∞

Aspheric data 3rd surface
K = 4.32691e-001 A 4=-2.01075e-005 A 6=-5.77042e-008 A 8= 2.18817e-010
A10=7.74314e-014

Side 4
K =-8.80639e-001 A 4=-1.89233e-005 A 6=-8.57520e-008 A 8= 4.23972e-010
A10=-5.11033e-014

9th page
K = 6.06800e+001 A 4=-2.73271e-006 A 6=-9.63836e-008 A 8= 1.03681e-009

Side 12
K = 3.45986e+001 A 4=-1.72460e-006 A 6=-2.27910e-007 A 8= 2.66175e-009

Side 14
K = 6.16063e+000 A 4= 1.73713e-005 A 6= 1.56379e-007 A 8=-5.99782e-010

Page 24
K =-5.25180e+001 A 4= 3.24345e-005 A 6= 6.21489e-008 A 8=-4.19270e-010
A10= 4.06004e-012

Various data Zoom ratio 2.88

Focal length 18.58 36.51 53.49
F number 3.56 4.68 5.87
Half angle of view (degrees) 36.32 20.51 14.32
Image height 13.66 13.66 13.66
Lens total length 125.55 116.84 125.36
BF 34.95 50.70 66.45

d 8 32.96 8.50 1.28
d10 3.15 3.89 4.29
d12 2.34 1.60 1.20
d18 3.38 9.00 12.35
d22 9.42 3.79 0.44
d26 34.95 50.70 66.45

Zoom lens group data group Starting plane Focal length
1 1 -29.86
2 9 75.86
3 11 -35.02
4 13 21.61
5 19 -57.76
6 23 50.77

[Embodiment of camera system]
FIG. 19 is a diagram showing the configuration of a camera system 10 according to an embodiment of the present invention. The camera system 10 includes a lens device 200 and a light receiving element (imaging element) 12 that receives an image formed by an optical system OL (not shown in FIG. 19) of the lens device 200 and generates a captured image.

Note that the lens device 200 may be configured to be detachable from the camera body 201, or the lens device 200 and the camera body 201 may be configured integrally (not detachably). When the lens device 200 and the camera body 201 are integrally configured, the lens device 200 does not need to be provided with the mount ring 212 or the mount section 213.

The camera body 201 may be a single-lens reflex camera or a mirrorless camera.

In such a camera system, noise in the image signal acquired by the image sensor 12 can be reduced while obtaining high optical performance.

Although preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist thereof.

OL Optical system L1 1st lens group L2 2nd lens group LR Rear group Lf Focus group 100, 516 Motor unit (actuator)
200, 300 Lens device 301, 517 Drive board (voltage transformation means)
302a-302d, 517a coil

Claims (25)

Consists of a first lens group with positive refractive power, a second lens group with negative refractive power, and a rear lens group with positive refractive power as a whole in the entire zoom range, which are arranged in order from the object side to the image side. an optical system in which the interval between matching lens groups changes, and the first lens group moves toward the object side during zooming from a wide-angle end to a telephoto end;
transformer means including a coil;
an actuator that is driven by a voltage from the voltage transformation means and moves a part of the lens portion of the optical system during focusing;
The coil is located at a position that is away from the most object-side surface of the optical system at the wide-angle end toward the image side by more than the maximum movement amount of the first lens group in the optical axis direction, and at a position of the optical system at the wide-angle end. A lens device characterized in that the lens device is disposed at a position closer to the object side than a surface closest to the image side and a position closest to the object side of the actuator. comprising a control unit that controls driving of the actuator;
2. The lens device according to claim 1, wherein a position of the actuator closest to the object is located closer to the object than the control unit in the optical axis direction. a holding member that holds the first lens group and moves together with the first lens group during zooming;
3. The lens device according to claim 1, wherein the coil is disposed within an outermost diameter range of the holding member when viewed in the optical axis direction. 4. The lens device according to claim 1, wherein the coil is disposed at a position that is at least twice as far away from the image plane as a back focus of the optical system at a wide-angle end. a guide tube having a guide groove for guiding the part of the lens portion;
a cam ring having a cam follower that engages with the guide groove and a cam groove that engages with the cam follower;
5. The lens device according to claim 1, wherein the coil is disposed offset from at least one of the guide groove and the cam groove. The lens device according to any one of claims 1 to 5, wherein the transformer has a plurality of coils, and the plurality of coils are distributed and arranged in a circumferential direction of the optical system. . a substrate having a plurality of surfaces non-parallel to each other in the circumferential direction of the optical system;
7. The lens device according to claim 6, wherein the plurality of coils are distributed and arranged on a plurality of surfaces of the substrate. When the amount of movement of the first lens group during zooming from the wide-angle end to the telephoto end is M1, and the focal length of the optical system at the wide-angle end is fw, the optical system is
0.5<|M1|/fw<1.3
8. The lens device according to claim 1, wherein the lens device satisfies the following conditional expression. When the effective diameter of the surface closest to the object side of the first lens group is B1obj_ea, and the effective diameter of the surface closest to the image side of the second lens group is B2img_ea, the optical system has the following characteristics:
1.5<B1obj_ea/B2img_ea<3.0
9. The lens device according to claim 1, wherein the lens device satisfies the following conditional expression. The lens group disposed closest to the object side of the rear group is a third lens group, and the effective diameter of the largest lens among the effective diameters of the lenses constituting the third lens group is B3max_ea, and the optical system at the wide-angle end. When the focal length of is fw, the optical system is
1.0<B3max_ea/fw<2.0
10. The lens device according to claim 1, wherein the lens device satisfies the following conditional expression. When the back focus of the optical system at the wide-angle end is skw, and the focal length of the optical system at the wide-angle end is fw, the optical system is
0.3<skw/fw<1.1
11. The lens device according to claim 1, wherein the lens device satisfies the following conditional expression. The distance on the optical axis from the most object-side surface of the second lens group to the most image-side surface of the second lens group is T2, and the distance on the optical axis from the most object-side surface of the second lens group to the most image-side surface of the second lens group is T2; When the distance on the optical axis from the surface closest to the object side of the final lens group to the surface closest to the image side of the final lens group is To, the optical system is
0.3<T2/To<1.0
12. The lens device according to claim 1, wherein the lens device satisfies the following conditional expression. The part of the lens portion is the second lens group,
13. The lens device according to claim 1, wherein the second lens group moves toward the object side when focusing from infinity to a close object. 14. The lens device according to claim 1, wherein the transformer includes a booster circuit that boosts the input voltage and outputs the boosted voltage. Consisting of a first lens group with negative refractive power arranged in order from the object side to the image side, and a rear group with positive refractive power as a whole over the entire zoom range, the distance between adjacent lens groups changes during zooming, resulting in a wide-angle lens. an optical system in which the first lens group moves toward the object side during zooming from the end to the telephoto end;
transformer means including a coil;
an actuator that is driven by a voltage from the voltage transformation means and moves a part of the lens portion of the optical system during focusing;
The coil is located at a position that is away from the most object-side surface of the optical system at the wide-angle end toward the image side by more than the maximum movement amount of the first lens group in the optical axis direction, and at a position of the optical system at the wide-angle end. A lens device characterized in that the lens device is disposed at a position closer to the object side than a surface closest to the image side and a position closest to the object side of the actuator. comprising a control unit that controls driving of the actuator;
16. The lens device according to claim 15, wherein a position of the actuator closest to the object is located closer to the object than the control unit in the optical axis direction. a holding member that holds the first lens group and moves together with the first lens group during zooming;
17. The lens device according to claim 15, wherein the coil is disposed within an outermost diameter range of the holding member when viewed in the optical axis direction. 18. The lens device according to claim 15, wherein the coil is disposed at a position that is at least twice as far away from the image plane as the back focus of the optical system at the wide-angle end. a guide tube having a guide groove for guiding the part of the lens portion;
a cam ring having a cam follower that engages with the guide groove and a cam groove that engages with the cam follower;
The lens device according to any one of claims 15 to 18, wherein the coil is disposed offset from at least one of the guide groove and the cam groove. The lens device according to any one of claims 15 to 19, wherein the transformer has a plurality of coils, and the plurality of coils are distributed and arranged in a circumferential direction of the optical system. . a substrate having a plurality of surfaces non-parallel to each other in the circumferential direction of the optical system;
21. The lens device according to claim 20, wherein the plurality of coils are distributed and arranged on a plurality of surfaces of the substrate. When the effective diameter of the surface closest to the object side of the first lens group is B1obj_ea, and the effective diameter of the surface closest to the image side of the second lens group disposed closest to the object side in the rear group is B2img_ea, the optical system teeth,
1.5<B1obj_ea/B2img_ea<3.0
22. The lens device according to claim 15, wherein the lens device satisfies the following conditional expression. a second lens group disposed closest to the object side in the rear group; and a third lens group disposed adjacent to the second lens group on the image side;
The part of the lens portion is the third lens group,
23. The lens device according to claim 15, wherein the third lens group moves toward the object side when focusing from infinity to a close object. 24. The lens device according to claim 15, wherein the transformer includes a booster circuit that boosts the input voltage and outputs the boosted voltage. The lens device according to any one of claims 1 to 24,
A camera system comprising: a light receiving element that receives an image formed by the optical system.

Images