Optical device and imaging device

Abstract

To provide a lens device capable of positioning a lens with high accuracy while reducing lens surface distortion with a simple configuration.SOLUTION: A lens device comprises a lens, a holding lens barrel that holds the lens, a biasing barrel that holds the lens between the holding lens barrel and the biasing barrel, and an elastic member that biases the biasing barrel toward the holding lens barrel. The holding lens barrel includes an optical axis direction receiving portion for positioning the lens in an optical axis direction and an orthogonal direction receiving portion for positioning the lens in an orthogonal direction to an optical axis. The elastic member biases the biasing barrel to cause the lens to be pressed against the optical axis direction receiving portion and the orthogonal direction receiving portion and cause the lens to be held with respect to the holding lens barrel in the optical axis direction and the orthogonal direction, and the lens device comprises a movement amount limiting portion that limits a relative movement amount between the biasing barrel and the holding lens barrel in the optical axis direction and the orthogonal direction.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a lens apparatus and an imaging apparatus. [Background technology]

[0002] In some lens barrels, such as interchangeable lenses, thermal caulking or adhesives are used to fix the lens to the lens barrel. In this case, the stress generated when fixing the lens to the lens barrel may cause a change in the surface accuracy of the lens (lens surface distortion), which may deteriorate the optical performance of the lens.

[0003] Patent Document 1 discloses a technique for pressing a lens toward a holding recess of a lens holder with a pressing member that snaps into the lens holder, thereby biasing and fixing the lens to the lens holder. The pressing portion of the pressing member that presses the lens is made of a ring-shaped elastic material such as foam or rubber, and the lens is pressed against the lens holder via the elastic material. This discloses a technique for fixing the lens to the lens holder while suppressing lens surface distortion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-109804 A Summary of the Invention [Problem to be solved by the invention]

[0005] In order to suppress distortion of the lens surface caused by the stress for fixing the lens when fixing the lens to the lens barrel, it is necessary to fix the lens with a weak force. Specifically, if the lens has a mass of about 10 g, by pressing and fixing the lens with a force of about 500 mN, the stress acting on the lens relative to the rigidity of the lens is small, and distortion of the lens surface can be suppressed to a small level.

[0006] However, when the lens is fixed via an elastic member provided in a narrow slit between the lens and the pressing member, the spring constant of the elastic member becomes very large, and the pressing force also becomes large. Also, it is not easy to fix the lens with the same force without variation for each individual lens.

[0007] Patent Document 1 does not disclose any fixation in a direction perpendicular to the optical axis of the lens. Even when the lens is fixed by press-fitting it into the lens barrel, the stress will worsen the distortion of the lens surface. Furthermore, if there is play between the lens barrel that holds the lens and the direction perpendicular to the optical axis of the lens, the lens will move and the lens position accuracy will deteriorate, which may result in deterioration of the optical performance of the lens.

[0008] SUMMARY OF THE PRESENT EMBODIMENTS An object of the present invention is to provide a lens device that has a simple configuration and is capable of positioning a lens with high accuracy while reducing lens surface distortion. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, a lens device as one aspect of the present invention comprises a lens, a holding barrel that holds the lens, a biasing tube that clamps the lens between the holding barrel, and an elastic member that biases the biasing tube toward the holding barrel, the holding barrel having an optical axis direction receiving portion for positioning the lens in the optical axis direction and an orthogonal direction receiving portion for positioning the lens in a direction orthogonal to the optical axis, and by biasing the biasing tube with the elastic member, the lens is pressed against the optical axis direction receiving portion and the orthogonal direction receiving portion, and is positioned and held in the optical axis direction and the orthogonal direction relative to the holding barrel, and has a movement amount limiting portion that limits the relative movement amount of the biasing tube and the holding barrel in the optical axis direction and the orthogonal direction when the lens is positioned and held. Effect of the Invention

[0010] The present invention provides a lens device that has a simple configuration and is capable of positioning a lens with high accuracy while reducing lens surface distortion. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing a configuration of an imaging device including a lens barrel of the present invention. [Diagram 2] FIG. 2 is a diagram showing a configuration of a lens barrel according to the present invention. [Diagram 3] FIG. 2 is a diagram showing a configuration of a lens barrel according to the present invention. [Figure 4] FIG. 3 is a cross-sectional view taken along line AA in FIG. [Diagram 5] FIG. 4 is a cross-sectional view taken along line BB in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. EXAMPLES

[0013] The system configuration of an imaging device 1 including a lens device 100 and a camera device 200 of the present invention will be described with reference to FIG.

[0014] The lens device 100 has, in order from the object side (left side in FIG. 1) to the image side (right side in FIG. 1), a first lens group 101, a second lens group 102, a third lens group 103, an aperture unit 104, a fourth lens group 105, and a fifth lens group 106. The second lens group 102 is supported by a lens barrel having a mechanism capable of moving with a component perpendicular to the optical axis, and constitutes an image blur correction unit that is driven in a plane perpendicular to the optical axis for image blur correction. The fourth lens group 105 is a focus lens group that is supported by a lens barrel that is movable in the optical axis direction, and adjusts focus by moving in the optical axis direction. The first lens group 101, the third lens group 103, and the fifth lens group 106 are held by a lens barrel that does not move in the optical axis direction.

[0015] Each of the first lens group 101, the second lens group 102, the third lens group 103, the fourth lens group 105, and the fifth lens group 106 is composed of one or more lenses. The positional relationship of the lenses in each lens group does not change during optical operations such as zooming, focus adjustment, and image blur correction.

[0016] The lens apparatus 100 also includes a gyro sensor 111 as a detection unit that detects vibrations of the lens apparatus 100, and a lens control unit 110 that controls the driving of the movable lens group and the aperture stop.

[0017] The lens control unit 110 controls the aperture driving unit 113 and the focus lens driving unit 114 to drive the aperture unit 104 and the fourth lens group 105, thereby changing the aperture diameter and adjusting the focus.

[0018] The lens control unit 110 calculates the amount of image blur correction based on the detection value of the gyro sensor 111, and performs image blur correction by controlling the image blur correction drive unit 112. The image blur correction is performed by driving the second lens group 102 in a y direction (yaw direction) and a p direction (pitch direction) that are perpendicular to each other in a plane perpendicular to the optical axis direction (x direction in the figure).

[0019] The lens control unit 110 also has a function of determining the holding state (change in attitude) of the lens device 100 or the camera device 200 based on the detection value of the gyro sensor 111.

[0020] The lens device 100 is detachably connected to a camera device 200 via a mount 120. The camera device 200 has an image sensor 201, and captures an image of a subject formed by an optical system within the lens device 100.

[0021] The camera device 200 includes a camera control unit 202, a release button 203 as an operating member, a main power supply operation unit 204, a recording unit 205, and the like. The release button 203 has a two-stage depression configuration, and can perform a first release operation at the first stage where the button is pressed shallowly, and a second release operation at the second stage where the button is pressed deeper. When the first release operation is performed, the camera control unit 202 cooperates with the lens control unit 110 as necessary to perform preparations to start shooting, such as returning from shooting standby, starting image blur correction, starting autofocus, and starting photometry. When the second release operation is performed, the camera control unit 202 shoots a picture and records the image in the recording unit 205.

[0022] In addition, power is exchanged between the camera device 200 and the lens device 100 via a contact block (not shown) provided on the mount 120, and shooting information is communicated between the camera control unit 202 and the lens control unit 110.

[0023] A lens barrel according to a first embodiment of the present invention will be described with reference to FIGS.

[0024] 2 to 5 are diagrams showing a five-group lens barrel 300 that holds the fifth lens group 106, as a lens barrel according to the first embodiment of the present invention.

[0025] Fig. 2 is a view of five-group barrel 300 as seen from the object side along the optical axis. Fig. 3 is a side view of five-group barrel 300 as seen from the lower side of the paper surface of Fig. 2. Fig. 4 is a cross-sectional view along the line AA in Fig. 2. Fig. 5 is a cross-sectional view along the line BB in Fig. 3.

[0026] The 5-group barrel 300 is a barrel that holds the lens 301 that constitutes the 5th lens group 106, and includes a biasing tube 302, a holding tube 303, and an elastic member 304. In this embodiment, the elastic member 304 is configured with two tension coil springs, but the present invention is not limited to this, and may be configured with a compression coil spring, a leaf spring, rubber, or the like. The elastic member 304 has a first hook portion provided at one end thereof and engaging with an elastic member fixing portion 302e of the biasing tube 302, and a second hook portion provided at the other end thereof and engaging with an elastic member fixing portion 303e of the holding tube 303. The two elastic members 304 are disposed at positions that are substantially opposite each other across the optical axis O.

[0027] The two tension coil springs of the elastic member 304 are disposed at an angle of approximately 45 degrees with respect to a plane perpendicular to the optical axis O. By disposing them in this manner, the resultant force of the tensile forces of the two tension coil springs also acts in a direction inclined at approximately 45 degrees with respect to a plane perpendicular to the optical axis O. Here, approximately 45 degrees with respect to the plane perpendicular to the optical axis means an angle of 30 degrees or more and 60 degrees or less, preferably 40 degrees or more and 50 degrees or less, and more preferably 42 degrees or more and 48 degrees or less with respect to the plane perpendicular to the optical axis.

[0028] Moreover, the two tension coil springs of the elastic member 304 are arranged so that their extension directions are approximately parallel to each other. It is preferable that the two tension coil springs of the elastic member 304 are arranged so that they are approximately parallel to each other, because the respective elastic forces act as a resultant force efficiently to bias the lens 301. Here, "the extension directions of the two tension coil springs being approximately parallel to each other" refers to an arrangement in which the angle between the extension direction of one and the extension direction of the other is 10 degrees or less, preferably 5 degrees or less, and more preferably 3 degrees or less.

[0029] 3, biasing tube 302 is biased in a diagonally downward left direction on the page (a direction inclined at approximately 45 degrees with respect to a plane perpendicular to the optical axis) toward holding tube 303 by elastic member 304. Lens 301 is sandwiched and disposed between holding tube 303 and biasing tube 302 in the optical axis direction and in a plane perpendicular to the optical axis.

[0030] The holding barrel 303 has three optical axis direction receiving portions 303c at approximately equal intervals of approximately 120 degrees in the circumferential direction centered on the optical axis, which receive the lens 301 in the optical axis direction. The biasing barrel 302 has three optical axis direction biasing portions 302c at approximately equal intervals of approximately 120 degrees in the circumferential direction centered on the optical axis. The lens 301 is pressed against the optical axis direction receiving portions 303c by the optical axis direction biasing portions 302c of the biasing barrel 302 receiving an elastic force from the elastic member 304, and is positioned in the optical axis direction. The optical axis direction receiving portions 303c may be configured at three or more positions, or may be configured all around the circumference.

[0031] The optical axis direction biasing portion 302c may be provided at three or more positions, or may be provided around the entire circumference.

[0032] As described above, the resultant force of the biasing forces acting on the biasing tube 302 by the two tension coil springs, which are the elastic member 304, acts near the optical axis. Therefore, the biasing tube 302 can bias the vicinity of the center of gravity of the lens 301 in the optical axis direction relative to the holding barrel 303. As a result, the lens 301 can be biased evenly in a well-balanced manner and positioned. This makes it possible to prevent the axis of the lens 301 from falling relative to the optical axis of the optical system of the lens device 100, which would otherwise deteriorate the optical performance of the entire lens device, by biasing the lens 301 by the resultant force acting on a position away from the center of gravity of the lens 301.

[0033] The holding barrel 303 has two optical axis orthogonal receiving portions 303d for positioning in a plane perpendicular to the optical axis of the lens 301. The biasing cylinder 302 is biased to the left side of the paper surface of FIG. 3 by a biasing force having a component in a plane perpendicular to the optical axis by two tension coil springs. The optical axis orthogonal receiving portions 303d arranged in two places on the holding barrel 303 are arranged on the opposite side to the side on which the two elastic member fixing portions 302e of the biasing cylinder 302 are arranged, with respect to a first plane parallel to the optical axis passing through the two elastic member fixing portions 303e. In addition, the optical axis orthogonal receiving portions 303d arranged in two places are arranged in positions symmetrical with respect to a second plane perpendicular to the first plane and including the optical axis, and are arranged at positions spaced approximately 120° apart from each other with the optical axis as the center.

[0034] Furthermore, in this embodiment, the optical axis orthogonal receiving portion 303d is configured to have an arc shape with a radius L1 centered on the position of the optical axis in a plane perpendicular to the optical axis. However, the optical axis orthogonal receiving portion 303d is not limited to being formed in an arc shape in a plane perpendicular to the optical axis, and may be configured to be cut out in a D-cut shape, for example. In that case, the optical axis orthogonal receiving portion 303d is configured so that the distance between the D-cut plane and the optical axis is L1.

[0035] The holding barrel 303 is provided with a guide portion 303f on the opposite side of the optical axis orthogonal direction receiving portion 303d with respect to the first plane. The guide portion 303f is provided to provisionally assemble and roughly position the lens 301 and the holding barrel 303 before the biasing tube 302 is assembled to the holding barrel 303. The guide portion 303f is formed in an arc shape with a radius of L2 centered on the optical axis position. A portion of the holding barrel 303 in a phase corresponding to the position of the optical axis orthogonal direction biasing portion 302d of the biasing tube 302 described later is cut out so that the optical axis orthogonal direction biasing portion 302d can abut and bias the outer diameter portion of the lens 301.

[0036] The biasing tube 302 has an optical axis orthogonal direction biasing portion 302d, which biases the lens 301 toward the optical axis orthogonal direction receiving portion 303d (left direction in FIG. 5) by the biasing force of the elastic member 304, on the opposite side of the optical axis orthogonal direction receiving portion 303d with respect to the first plane. This allows the lens 301 to be positioned relative to the holding tube 303 in a plane perpendicular to the optical axis.

[0037] Here, the radius L1 of the receiving portion 303d in the direction perpendicular to the optical axis, the radius L2 of the guide portion 303f in the direction perpendicular to the optical axis, and the radius R of the outer diameter of the lens 301 are given by: L1=R (1) R <L2 ··· (2) That is, the guide portion 303f is configured so that there is play between the holding barrel 303 and the lens 301 in at least one direction in a plane perpendicular to the optical axis when the lens 301 is in contact with the optical axis direction receiving portion 303c and the optical axis orthogonal direction receiving portion 303d.

[0038] First, by configuring the holding barrel 303 to satisfy the formula (1), the lens 301 is positioned in a state where it is loosely attached to the optical axis orthogonal receiving portion 303d of the holding barrel 303, so that the lens 301 can be fixed to the holding barrel 303 without decentering. This makes it possible to prevent a deterioration in the optical performance of the entire lens device 100. In addition, the difference (L2-L1) (>0) between the radius L2 and the radius L1 is set to be as small as possible within a range in which the lens 301 can be provisionally assembled to the holding barrel 303, taking into consideration manufacturing errors and the like. The difference (L2-L1) should be such that when the lens 301 is provisionally assembled to the holding barrel 303, the lens 301 and the holding barrel 303 can be held with play in a plane perpendicular to the optical axis, rather than being pressed in. For example, L2 can be set to be larger than L1 by, for example, 0.01 mm. In the illustrated embodiment, the guide portion 303f is formed in an arc shape with a radius of L2 centered on the optical axis position, but the present invention is not limited to this shape. It is sufficient that the guide portion 303f is provided on the opposite side of the optical axis orthogonal direction receiving portion 303d with respect to the first plane, with the closest position being a position away from the optical axis position by a radius R.

[0039] As a result, the lens 301 is not press-fitted at the stage of temporarily holding the lens 301 in the holding barrel 303, and no stress is applied to the lens 301, so that distortion of the lens surface is not aggravated.

[0040] Furthermore, at the stage where lens 301 is temporarily held in holding barrel 303, lens 301 is held in a position close to the state in which the assembly of biasing barrel 302 is completed, making subsequent assembly and fixing easier. Furthermore, when an impact force having a component in a direction perpendicular to the optical axis and in a direction opposite to the biasing force of elastic member 304 is applied to lens device 100 in the completed assembled state, biasing barrel 302 and lens 301 will be displaced relative to holding barrel 303. However, since lens 301 abuts against guide portion 303f of holding barrel 303, lens 301 will not be displaced by more than the difference between L2 and L1.

[0041] In this way, the elastic member 304, which urges the lens 301 against the holding barrel 303 via the urging barrel 302, urges the lens 301 at an angle relative to the optical axis, so that the single urging barrel 302 realizes positioning of the lens 301 in the optical axis direction and in the direction within a plane perpendicular to the optical axis.

[0042] Regarding the positioning of the lens 301 in the optical axis direction, the lens 301 is positioned by being pushed against the optical axis direction receiving portion 303c of the holding barrel 303 by the biasing tube 302. By creating the surface of the optical axis direction receiving portion 303c with high precision, the position of the lens 301 in the optical axis direction can be accurately positioned, and the lens surface can be prevented from being tilted. The biasing force in the optical axis direction by the elastic member 304 is set to a force of about 2 to 10 times the lens mass. Specifically, if the lens mass is 10 g, the biasing force in the optical axis direction by the elastic member 304 is set to about 200 mN to 1000 mN. This is smaller than the stress applied when the lens is fixed to the barrel by thermal caulking, for example, and distortion occurring on the lens surface can be suppressed to a small value, thereby suppressing deterioration of optical performance.

[0043] The positioning of the lens 301 in a direction perpendicular to the optical axis is performed by the biasing tube 302 by moving the lens 301 to the optical axis perpendicular direction receiving portion 303d of the holding tube 303. The distance (arc radius) L1 from the optical axis of the optical axis perpendicular direction receiving portion 303d and the radius R of the lens 301 are set as L1=R, so the lens 301 has a reference surface that can be positioned with good eccentricity accuracy with respect to the holding tube 303. The biasing force of the elastic member 304 biasing the lens 301 in a direction perpendicular to the optical axis is set to a force of about 2 to 10 times the lens mass. Specifically, if the lens mass is 10 g, the biasing force of the elastic member 304 in the optical axis direction is set to about 200 mN to 1000 mN. This is very small compared to the stress applied to the lens 301 when the lens 301 is fixed by pressing it in the radial direction into the holding tube 303. Therefore, when fixing the lens according to the present invention to the lens barrel, distortion occurring on the lens surface can be kept small, and deterioration of optical performance can be suppressed.

[0044] In this embodiment, a tension coil spring is used as the elastic member 304. If a wave washer is used as the elastic member 304, it is difficult to secure a sufficiently long space in the biasing direction, and it is difficult to reduce the spring constant. Therefore, a slight change in the position in the biasing direction (compressed length of the wave washer) causes a large change in the biasing force, making it difficult to apply the desired biasing force. As described above, if the desired biasing force is a relatively small biasing force of about 200 mN to 1000 mN, it is even more difficult to apply the desired biasing force. In the case of a resin spring or rubber, the spring constant becomes large, making it difficult to apply the desired biasing force, and there is also a concern that the biasing force will change over time if creep occurs.

[0045] When tension is used, if the spring length can be secured, the spring constant can be set small, and it is easy to realize a weak biasing force as designed. In addition, the risk of the biasing force changing over time can be kept low. Therefore, in this embodiment, it is possible to achieve both the desired biasing force and a space-saving arrangement. Regarding the elastic member 304, as long as the above requirements are met, a leaf spring or the like can be used in addition to a tension coil spring.

[0046] In order to stably and precisely bias and fix the lens 301, the resultant force of the biasing forces acting on the two elastic member fixing portions 302e with which the elastic member 304 engages must act near the center of gravity P of the lens 301. Region V shown in FIG. 4 indicates an area within half the distance from the center of gravity P of the lens 301 to the outer shape of the lens 301. In other words, region V is an area surrounded by the midpoint of the line segment from the center of gravity P of the lens 301 to the outer shape of the lens 301. If the resultant force of the biasing forces of the elastic member 304 is configured to act within region V, the lens 301 can be stably and precisely biased and fixed to the holding barrel 303.

[0047] Conversely, when the resultant of the urging forces acts at a position outside the region V, the resultant of the urging forces and the reaction force against the urging force of the optical axis direction receiving portion 303c become unbalanced, and the lens is not sufficiently pressed down in the phase where the urging force is weak, which may cause the lens to fall over. Also, when the resultant of the urging forces acts at a position far removed from the region V, there is a risk that the lens will fall over due to a moment, particularly when an impact force is applied from the outside, due to the relationship with the reaction force against the urging force from the optical axis direction receiving portion 303c.

[0048] In this case, in order to apply a biasing force within the region V of the lens 301, two elastic member fixing parts 302e, which engage with tension coil springs as the elastic member 304, are arranged at positions that are substantially opposite each other with the vicinity of the center of gravity P of the lens 301 in between. Furthermore, as shown in FIG. 3, the two tension coil springs are arranged substantially parallel to each other and tilted at approximately 45 degrees with respect to a plane perpendicular to the optical axis. By arranging them in this manner, it is possible to achieve a resultant force of the biasing forces acting within the region V with a small number of springs and a small space. The elastic member 304 is not limited to being composed of two tension coil springs, and three or more elastic members may be used as long as the lens 301 can be biased so that the resultant force of the biasing forces acts within the region V.

[0049] Next, the assembly of this unit will be described. First, the lens 301 is placed in the holding barrel 303, aligned with the optical axis direction receiving portion 303d and the guide portion 303f. Since the lens 301 is not press-fitted in the radial direction, no special tools are required, and the lens 301 can be easily placed in the optical axis direction receiving portion 303c of the holding barrel 303 without applying stress to the lens 301 for press-fitting.

[0050] Next, the biasing tube 302 is assembled into the holding tube 303. The biasing tube 302 has bayonet claws 302g at three locations spaced 120 degrees apart to engage with the holding tube 303. The holding tube 303 has bayonet grooves 303g at three locations spaced 120 degrees apart to correspond to the bayonet claws 302g. The holding tube 303 has an assembly groove at a position rotated about 15 degrees around the optical axis from the position where the bayonet grooves 303g are arranged, through which the bayonet claws 302g pass when the biasing tube 302 is assembled. When the biasing tube 302 is assembled into the holding tube 303, the biasing tube 302 is inserted in this phase state to a predetermined position in the optical axis direction relative to the holding tube 303, and then rotated 15 degrees to be assembled into the completed position shown in FIG. 2. This is the same as the configuration and assembly of a general bayonet system.

[0051] In this state, the tension coil springs are fixed by hooking the hook portions of the two tension coil springs, which are elastic members 304, on elastic member fixing portions 302e and 303e. This also determines the position of the rotation phase of biasing tube 302 and holding tube 303 about the relative optical axis.

[0052] As described above, lens 301 can be easily fixed to holding barrel 303 with high precision without using special tools such as those used for thermal caulking of a lens during assembly.

[0053] Next, the behavior of the lens device when an impact is applied thereto will be described. 4, in a state where lens 301 is assembled to holding barrel 303 by biasing cylinder 302 and elastic member 304, optical axis orthogonal direction stopper portion 302b and optical axis orthogonal direction stopper portion 303b are configured to have a gap d2 in a direction perpendicular to the optical axis. It is desirable to make gap d2 as small as possible, but not zero, even when manufacturing variations in parts are taken into consideration.

[0054] The optical axis direction stopper portion 303a and the optical axis direction stopper portion 302a are configured to have a gap d1 in the optical axis direction between the bayonet groove 303g provided in the holding barrel 303 and the bayonet claw 302g provided in the biasing barrel 302. It is desirable to make the gap d1 as small as possible, but not zero, even when the manufacturing variation of the parts is taken into consideration.

[0055] When the lens 301 is held by the above-mentioned bayonet mechanism, there is some play in the relative position of the actuating tube 302 and the holding tube 303 in the optical axis direction and the perpendicular direction, and a movement amount limiting section is formed which limits the relative movement amount.

[0056] When an impact caused by a fall or the like is applied to the lens device 100, and a force greater than the biasing force of the elastic member 304 of the biasing cylinder 302 is applied in the opposite direction, the biasing cylinder 302 moves in the direction opposite to the biasing force. As a result, the lens 301 moves in the same manner. However, in the direction perpendicular to the optical axis, the optical axis perpendicular direction stopper portion 302b and the optical axis perpendicular direction stopper portion 303b act as stoppers that define the movement limit, and the relative displacement of the biasing cylinder 302 and the lens 301 does not exceed d2. When the impact force is removed, the biasing force of the elastic member 304 returns them to their original positioning positions.

[0057] In the optical axis direction, optical axis direction stopper portion 303a of holding barrel 303 and optical axis direction stopper portion 302a of biasing barrel 302 act as stoppers that define the movement limit, and the relative displacement amount of biasing barrel 302 and lens 301 does not exceed d1. When the impact force is removed, the biasing force of elastic member 304 returns them to their original positioning position.

[0058] At this time, if the gap d2 in the direction perpendicular to the optical axis and the gap d1 in the optical axis direction are large, the relative movement amount between the biasing cylinder 302 and the lens 301 also becomes large, but in this embodiment, the gaps d2 and d1 are set small, so the movement amount is small. This reduces the risk of the lens tilting and becoming twisted when the movable amount is large, and the risk of the lens not reaching the position due to friction when the movable amount is small or when the lens is press-fitted and fixed. In other words, even if an impact is applied to the lens device 100, the relative positional relationship between the lens 301 and the holding barrel 303 does not change, and it is easy to return to the original relative positional relationship. In other words, a lens with little change in optical performance even when an impact is applied can be realized.

[0059] As described above, by applying the configuration of this embodiment, it is possible to reduce distortion of the lens surface and position the lens with high precision, thereby realizing a lens device that prevents deterioration of optical performance due to the assembly of the lens into the lens device. In particular, in order to reduce the overall length of the lens and make it lightweight, it is desirable to make the center thickness and peripheral thickness of the lens as thin as possible. However, making the lens thin reduces the rigidity of the lens, making it more susceptible to distortion of the lens surface. Even in such cases, by using the present invention, it is possible to reduce distortion of the lens surface and realize a high-performance lens.

[0060] Even if lens surface distortion occurs, if the same lens surface distortion occurs on the object side and image side (rear surface) of the lens, the adverse effect on optical performance may be canceled. On the other hand, when using a mirror lens (reflective optical element) used in a telescope, etc., there is no cancellation relationship as described above, so the surface distortion of the mirror lens directly leads to deterioration of optical performance. In the present invention, since the lens surface distortion itself can be suppressed to a small value without relying on the cancellation relationship, it is also effective for the holding configuration of the mirror lens.

[0061] In this embodiment, the case where the lens is applied to the fifth lens group is illustrated, but the present invention is not limited thereto, and can be applied to positioning and fixing the lens in other lens groups to the lens barrel. In addition, in the above embodiment, the lens is applied to a lens group that does not move for focusing or zooming, but the present invention is not limited thereto, and can be similarly applied to a lens group that moves. When applied to a moving lens group, it is advisable to determine the magnitude of the elastic force that biases the lens, taking into consideration the acceleration and direction during the movement.

[0062] The disclosure of this embodiment includes the following configuration. (Configuration 1) Lenses and a lens holding barrel for holding the lens; an actuating cylinder that holds the lens between itself and the holding barrel; an elastic member that urges the urging tube toward the holding tube, the holding barrel has an optical axis direction receiving portion for positioning the lens in the optical axis direction, and an orthogonal direction receiving portion for positioning the lens in a direction orthogonal to the optical axis, By biasing the biasing cylinder by the elastic member, the lens is pressed against the optical axis direction receiving portion and the orthogonal direction receiving portion, and is positioned and held in the optical axis direction and the orthogonal direction relative to the holding barrel, a lens device having a movement limiting portion that limits the relative movement of the biasing tube and the holding tube in the optical axis direction and the perpendicular direction when the lens is positioned and held in the lens device; (Configuration 2) The lens device described in configuration 1, characterized in that when the lens is in contact with the optical axis direction receiving portion and the orthogonal direction receiving portion, the holding barrel has a guide portion configured so that the lens has play in a plane perpendicular to the optical axis. (Configuration 3) The orthogonal direction receiving portion has an arc shape having a radius equal to the radius of the lens, the guide portion has an arc shape centered on the position of the optical axis of the lens in a state in which the lens is in contact with the optical axis direction receiving portion and the orthogonal direction receiving portion, 3. The lens device according to claim 2, wherein the radius of the arc shape of the guide portion is larger than the radius of the lens. (Configuration 4) The lens device according to any one of configurations 1 to 3, wherein the movement amount limiting portion is a bayonet mechanism configured between the holding barrel and the biasing barrel. (Configuration 5) 5. The lens device according to any one of configurations 1 to 4, wherein the elastic member is composed of at least two coil springs. (Configuration 6) The lens device according to configuration 5, wherein a resultant force of the biasing forces acting on the lens by the at least two coil springs acts on an area within 1 / 2 of the distance from the center of gravity of the lens to its outer shape. (Configuration 7) The elastic member is two coil springs, The two coil springs are disposed at positions facing each other across the center of gravity of the lens, One end of each of the two coil springs engages with the holding barrel, and the other end of each of the two coil springs engages with the biasing barrel, and the two coil springs are disposed obliquely with respect to a plane perpendicular to the optical axis. 7. A lens device according to any one of configurations 1 to 6. (Configuration 8) 8. The lens device according to claim 7, wherein each of the two coil springs is disposed so as to have an angle of 30 degrees or more and 60 degrees or less with respect to a plane perpendicular to the optical axis. (Configuration 9) 8. The lens device according to configuration 7, wherein each of the two coil springs is disposed so as to have an angle of 40 degrees or more and 50 degrees or less with respect to a plane perpendicular to the optical axis. (Configuration 10) 8. The lens device according to configuration 7, wherein the two coil springs are arranged parallel to each other. (Configuration 11) 11. An imaging device comprising: a lens device according to any one of configurations 1 to 10; and an imaging element that captures an image formed by the lens device. [Explanation of symbols]

[0063] 100 Lens device 106 5th lens group 301 Lens 302 Force tube 303 Holding tube 304 Elastic Members 303c Optical axis direction receiver 303d Optical axis perpendicular direction receiving part

Claims

1. An optical element, a holding cylinder for holding the optical element, a biasing cylinder for sandwiching the optical element between the holding cylinder, and an elastic member for biasing the biasing cylinder toward the holding cylinder, wherein the holding cylinder has an optical axis direction receiving portion for positioning in the optical axis direction of the optical element and an orthogonal direction receiving portion for positioning in the direction orthogonal to the optical axis of the optical element, by biasing the biasing cylinder with the elastic member, the optical element is pressed against the optical axis direction receiving portion and the orthogonal direction receiving portion, and is positioned and held in the optical axis direction and the orthogonal direction with respect to the holding cylinder, and the optical device is characterized by having a movement amount limiting portion for limiting the relative movement amount between the biasing cylinder and the holding cylinder in the optical axis direction and the orthogonal direction in a state where the optical element is positioned and held.

2. In a state where the optical element is in contact with the optical axis direction receiving portion and the orthogonal direction receiving portion, the holding cylinder has a guide portion configured to have a gap with the optical element in a plane perpendicular to the optical axis, according to the optical device of claim 1.

3. The orthogonal direction receiving portion has an arc shape with a radius equal to the radius of the optical element, the guide portion has an arc shape centered on the position of the optical axis of the optical element in a state where the optical element is in contact with the optical axis direction receiving portion and the orthogonal direction receiving portion, and the radius of the arc shape of the guide portion is larger than the radius of the optical element, according to the optical device of claim 2.

4. The movement amount limiting portion is a bayonet mechanism configured between the holding cylinder and the biasing cylinder, according to the optical device of claim 1.

5. The elastic member is composed of at least two coil springs, according to the optical device of claim 1.

6. The resultant force of the biasing forces acting on the optical element by the at least two coil springs acts in a region within 1 / 2 of the distance from the center of gravity to the outer shape of the optical element, according to the optical device of claim 5.

7. The elastic member is two coil springs, the two coil springs are arranged at positions facing each other with the center of gravity of the optical element interposed therebetween, one end of each of the two coil springs is engaged with the holding cylinder, the other end of each of the two coil springs is engaged with the biasing cylinder, and they are arranged obliquely with respect to a plane perpendicular to the optical axis The optical device according to claim 1.

8. The optical device according to claim 7, wherein each of the two coil springs is arranged to have an angle of 30 degrees or more and 60 degrees or less with respect to a plane perpendicular to the optical axis.

9. The optical device according to claim 7, wherein each of the two coil springs is arranged to have an angle of 40 degrees or more and 50 degrees or less with respect to a plane perpendicular to the optical axis.

10. The optical device according to claim 7, wherein the two coil springs are arranged parallel to each other.

11. The optical device according to claim 1, wherein the optical element is a lens.

12. The optical device according to claim 1, wherein the optical element is a mirror.

13. An imaging device, comprising: the optical device according to any one of claims 1 to 12; and an imaging element that captures an image formed by the optical device.

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