Optical device and imaging apparatus

Abstract

To provide an optical device that can prevent a reduction in the position detection accuracy of an optical element.SOLUTION: An optical device has: a movable lens barrel that holds an optical element; a stationary lens barrel that holds the movable lens barrel movably in an optical axis direction; and a first position detection unit that includes a detector held on one of the movable lens barrel and the stationary lens barrel, and a scale to be detected held on the other of the movable lens barrel and the stationary lens barrel. The stationary lens barrel has a first light shielding wall and a second light shielding wall that are formed on an inner wall of the stationary lens barrel toward an inner diameter side, and at least part of each of the light shielding walls overlap each other in a circumferential direction centered on an optical axis and are separated from each other in a radial direction on a cross section perpendicular to the optical axis. The first position detection unit is arranged in a space on the cross section surrounded by the inner wall of the stationary lens barrel and the first and second light shielding walls.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an optical device and an imaging device. [Background technology]

[0002] In a lens barrel (zoom optical system), image plane fluctuation occurs when the lens group is moved to change the magnification, so the focus lens is moved to correct the image plane fluctuation and control is performed to maintain the in-focus state. The movement trajectory of the focus lens is predetermined by electronic cam data for each subject distance. In such a zoom optical system, in order to change the magnification while maintaining the in-focus state, it is necessary to always accurately maintain the relationship between the position of the moving lens group and the position of the focus lens, which is determined by the electronic cam data.

[0003] Patent document 1 discloses a lens driving device that detects the position of a lens moved by a stepping motor using a detection means that combines an optical sensor and a reflective scale fixed to the lens holding part, enabling accurate focusing control regardless of backlash or manufacturing errors in the driving mechanism.

[0004] In such a position detection means using an optical sensor, a minimum gap is required between the optical sensor and the reflective scale so that they do not come into contact with each other. Therefore, light may enter through this gap, causing various problems. Patent Document 2 discloses an optical device in which a light-shielding wall is provided between the optical sensor and the image sensor to prevent light from the light-emitting part of the optical sensor from passing through the gap and reaching the image sensor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-204941 A [Patent Document 2] JP 2016-045283 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the configuration of Patent Document 2, although the optical path from the position detection unit to the image sensor is shielded by the light shielding wall, the space between the inner wall of the upper part of the lens barrel and the light shielding wall is not shielded, so there is a possibility that light incident from the object side of the lens passes between the inner wall and the light shielding wall, is reflected by the inner wall of the lens barrel, and reaches the sensor. When stray light other than the light emitted from the light emitting unit reflected by the reflective scale is reflected by the reflective scale and reaches the light receiving unit of the optical sensor, the amount of light received changes, which may reduce the position detection accuracy.

[0007] SUMMARY OF THE PRESENT DISCLOSURE In view of the above, an object of the present invention is to provide an optical device capable of suppressing a decrease in the accuracy of detecting the position of an optical element. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the optical device of the present invention comprises a movable barrel that holds an optical element and is movable in the optical axis direction, a fixed barrel that holds the movable barrel, and a first position detection unit that includes a detector provided on one of the movable barrel or the fixed barrel, and a detected object provided on the other of the movable barrel or the fixed barrel, wherein a first light-shielding wall and a second light-shielding wall are formed on the inner wall of the fixed barrel, at least a portion of the first light-shielding wall and the second light-shielding wall overlap each other when viewed from a radial direction and are spaced apart from each other in the radial direction, and the first position detection unit is arranged in a space surrounded by the first light-shielding wall and the second light-shielding wall and the inner wall of the fixed barrel in a cross section perpendicular to the optical axis. Effect of the Invention

[0009] According to the present invention, it is possible to provide an optical device capable of suppressing a decrease in the accuracy of detecting the position of an optical element. [Brief description of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of an entire lens barrel according to a first embodiment. [Diagram 2] 1 is a cross-sectional view of a lens barrel according to a first embodiment, as viewed from the object side. [Diagram 3] FIG. 2 is a perspective view of a second group movement frame in the lens barrel of the first embodiment. [Figure 4] FIG. 2 is a perspective view of a front fixed barrel in the lens barrel of the first embodiment. [Diagram 5] 4 is a cross-sectional view showing external light entering a space in the lens barrel of the first embodiment. FIG. [Figure 6] 3 is a cross-sectional view taken along line BB in FIG. 2 of the lens barrel according to the first embodiment of the present invention. [Figure 7] 4 is a cross-sectional view of a reset detection portion in the lens barrel of the first embodiment. FIG. [Figure 8] 1 is a diagram showing a conventional optical path of external light incident from the front surface of a lens until it reaches an optical sensor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In a lens barrel (zoom optical system, optical device), image plane fluctuation occurs when the lens group is moved in the optical axis direction to change the magnification, so the focus lens is moved to correct the image plane fluctuation and control is performed to maintain the in-focus state. The movement trajectory of the focus lens is predetermined for each subject distance and saved as electronic cam data. In such a zoom optical system, in order to change the magnification while maintaining the in-focus state, it is necessary to always accurately maintain the relationship between the position of the moving lens group and the position of the focus lens, which is determined as electronic cam data.

[0012] A driving mechanism consisting of a stepping motor, a feed screw rotated by the stepping motor, and a rack attached to a lens holding part and meshing with the feed screw is often used in the lens barrel of a video camera. However, there is backlash in the meshing part of the feed screw and the rack of the driving mechanism, and in the joint part between the lens holding member and the rack. In addition, the feed screw and the rack contain manufacturing errors such as an error in the screw pitch. Such backlash and manufacturing errors cause a mismatch between the number of driving pulses applied to the stepping motor and the actual position of the variable magnification lens. As a result, the relationship between the position of the variable magnification lens and the position of the focus lens deviates from the relationship determined by the cam data, and a focus shift occurs as the magnification changes.

[0013] Conventionally, a lens driving device has been disclosed that detects the position of a lens moved by a stepping motor using a detection means that combines an optical sensor and a reflective scale fixed to a lens holding part, thereby enabling accurate focusing control regardless of backlash or manufacturing error of the driving mechanism. In such a position detection means using an optical sensor, a minimum gap is required between the optical sensor and the reflective scale so that they do not come into contact with each other, and light can enter through this gap, causing various problems. EXAMPLES

[0014] 1 is a cross-sectional view of a lens barrel 100 according to a first embodiment of the present invention. In this specification, in order to clarify the positional relationship of the configuration of the device in each drawing, the optical axis direction is defined as the X direction, and directions perpendicular to each other in a plane perpendicular to the X direction are defined as the Y direction and the Z direction. In particular, although this is not intended to limit the arrangement of the lens device of the present invention, the drawings and explanations will be given assuming that the Z direction is the vertical direction and the Y direction is the horizontal direction.

[0015] Lens barrel 100 includes a variable magnification optical system (zoom lens system) made up of five lens groups L1 to L5, each of which includes at least one optical element; a light amount adjustment unit 6; an ND unit 7; and an IR unit 8.

[0016] The first lens group L1 does not move in the optical axis direction. The second lens group L2, the third lens group L3, and the fifth lens group L5 move in the optical axis direction to change the magnification. The third lens group L3 is composed of the 3a lens group L3a and the 3b lens group L3b, and serves not only as a magnification change mechanism but also as an optical system for image blur correction. The 3b lens group L3b is an anti-vibration lens group that shifts in a direction perpendicular to the optical axis of the photographing optical system to reduce image blur. The fourth lens group L4 moves in the optical axis direction to correct the image plane fluctuation caused by the magnification change and adjust the focus.

[0017] The first lens group holding frame 1 holds the first lens group L1. The second lens group movement frame (moving barrel) 2 holds the second lens group L2. The third lens group movement frame 3 holds the 3a lens group L3a, and the vibration isolation movement frame 30 holds the 3b lens group L3b. The vibration isolation movement frame 30 is attached to the third lens group movement frame 3 so as to be movable in a direction perpendicular to the optical axis. The fourth lens group movement frame 4 holds the fourth lens group L4. The fifth lens group movement frame 5 holds the fifth lens group L5.

[0018] The front fixed barrel (fixed barrel) 9 has an object side end fixed to the first lens group holding frame 1, and fixes the first lens group L1 at a predetermined position. It also has a rear end connected to the rear fixed barrel 11. The middle fixed barrel 10 holds a light amount adjustment unit 6, and has a rear end connected to the rear fixed barrel 11. The light amount adjustment unit 6 changes the aperture diameter of the optical system by moving the diaphragm blades in a plane perpendicular to the optical axis using a drive unit (not shown), thereby adjusting the amount of light. The rear fixed barrel 11 has an object side end fixed to the front fixed barrel 9 and the middle fixed barrel 10, and has a rear end connected to the image sensor holding frame 12.

[0019] The image sensor holding frame 12 has an object side end fixed to the rear fixed lens barrel 11, and contains an ND unit 7, an IR unit 8, and an image sensor (not shown). If the light amount is adjusted only by changing the area of ​​the opening of the light amount adjustment unit 6, the opening of the light amount adjustment unit 6 becomes small when shooting a high-luminance subject, and optical performance deteriorates due to the diffraction of light. Therefore, the ND unit 7 reduces the amount of light using a filter. When used in the visible light range, the IR unit 8 is configured with a mechanism that arranges an infrared light cut filter that cuts near-infrared light on the object side of the optical axis direction of the image sensor, and removes the infrared light cut filter when used in the near-infrared light range. The image sensor (not shown) is an image sensor that photoelectrically converts the subject image formed by the first to fifth lens groups L1 to L5.

[0020] The second lens group moving frame 2 is supported by second lens group guide bars 13A and 13B, both ends of which are held by the front fixed lens barrel 9 and the rear fixed lens barrel 11, so as to be movable in the optical axis direction. The third lens group moving frame 3 is supported by a third lens group guide bar 14, both ends of which are held by the center fixed lens barrel 10 and the rear fixed lens barrel 11, so as to be movable in the optical axis direction. The fourth lens group moving frame 4 is supported by a fourth lens group guide bar 15, both ends of which are held by the center fixed lens barrel 10 and the rear fixed lens barrel 11, so as to be movable in the optical axis direction. The fifth lens group moving frame 5 is supported by a fifth lens group guide bar 16, both ends of which are held by the center fixed lens barrel 10 and the rear fixed lens barrel 11, so as to be movable in the optical axis direction. The second lens group moving frame 2, the third lens group moving frame 3, and the fifth lens group moving frame 5 are each moved in the optical axis direction by a stepping motor (not shown). The fourth lens group moving frame 4 is moved in the optical axis direction by a voice coil motor (not shown). Each of the moving frames, the second lens group moving frame 2 to the fifth lens group moving frame 5, holds a reflective scale. The rear fixed barrel 11 holds respective optical sensors at positions facing the reflective scales held by the second lens group moving frame 2 to the fifth lens group moving frame 5. The position of each moving frame is detected by a pair of the reflective scale and the optical sensor, and details will be described later.

[0021] When the user inputs a zoom operation, the second lens group movement frame 2 is moved in the optical axis direction by the stepping motor. When the second lens group movement frame 2 moves in the optical axis direction, its position in the optical axis direction is detected by an optical sensor (optical detector) 18 and a reflective scale (detected object) 17. The third lens group movement frame 3 and the fifth lens group movement frame 5 are moved along a movement trajectory determined for each position of the second lens group movement frame 2 detected above, and magnification is changed. The fourth lens group movement frame 4 is moved along a movement trajectory determined for each position (focal length) of the second lens group movement frame 2 detected above and for each subject distance, and magnification is changed while maintaining the focused state.

[0022] Here, with reference to Fig. 8, an optical path of external light OL incident from the front surface of the first lens group L1 held by the first lens group holding frame 500 in a conventional lens barrel is described, where the external light OL is reflected inside the barrel and reaches the optical sensor 501. Fig. 8(a) shows the entire optical path of external light OL incident from the front surface of the first lens group L1, is reflected inside the barrel, and reaches the optical sensor 501. Fig. 8(b) shows an enlarged view of the periphery of the optical sensor 501.

[0023] The reflective scale 502 is fixed to a scale holder 504 formed on a second lens group movement frame 503. The optical sensor 501 is disposed in an opening of a front fixed barrel 505 formed in a position facing the reflective scale 502. The optical sensor 501 is mounted on an FPC (Flexible Printed Circuits), which is fixed to the front fixed barrel 505. During zooming, the reflective scale 502 moves integrally with the second lens group movement frame 503 in the optical axis direction (left and right direction in FIG. 8). In this specification, it is assumed that the reflective scale 502 is fixed to the second lens group movement frame 503 and the optical sensor 501 is fixed to the front fixed barrel 505, but the present invention is not limited to this. The reflective scale may be fixed to the front fixed barrel 505 and the optical sensor 501 may be fixed to the second lens group movement frame 503. That is, it is sufficient that the reflective scale 502 is fixed to one of the second lens group movement frame 503 or the front fixed barrel 505, and the optical sensor 501 is fixed to the other of the second lens group movement frame 503 or the front fixed barrel 505.

[0024] The optical sensor 501 has a light emitting unit and a light receiving unit, and the light emitting unit irradiates light onto the reflective scale 502 and the light receiving unit receives the reflected light. A periodic pattern is formed in the optical axis direction on the reflective scale 502. Therefore, during movement, the actual position in the optical axis direction can be detected by reading the light reflected by the pattern of the reflective scale 502 with the light receiving unit.

[0025] 8(b), a predetermined gap A is set between the scale holder 504 and the front fixed barrel 505 so that they do not come into contact with each other when moving. Therefore, as shown in FIG. 8(b), external light OL incident from the object side of the first lens group L1 passes through the gap A, is reflected a first time by the inner wall of the front fixed barrel 505, is reflected a second time by the reflective scale 502, and then may reach the optical sensor 501.

[0026] When external light OL reflected by the inner wall of the lens barrel reaches the light receiving section of optical sensor 501, the amount of light detected by the light receiving section changes significantly, degrading the position detection accuracy. Also, it is possible that the light path will reach optical sensor 501 after being reflected by the surface of another shiny metal member, and in such a case, the position detection accuracy may be further degraded.

[0027] Therefore, the present invention provides a lens device that suppresses a decrease in the accuracy of lens position detection by optical position detection and prevents malfunction of the lens drive control. With reference to Figures 2 to 7, the structure of the lens barrel of the present invention that prevents stray light reflected inside the barrel including the guide bar from reaching optical sensor 18 will be described.

[0028] The second lens group movement frame 2 of the present invention will be described with reference to Figs. 2 and 3. Fig. 2 shows a cross-sectional view of the lens barrel 100 as viewed from the object side. Fig. 3 shows a perspective view of the second lens group movement frame 2. The second lens group movement frame 2 is formed with a lens holding portion 2a, a sleeve (guide sleeve) 2b, a scale holding portion 2c, a reinforcing portion 2d, a U-shaped groove 2e, and a flange portion (second flange portion) 2f. The second lens group L2 fits into the lens holding portion 2a, and is fixed to the second lens group movement frame 2 by thermal caulking.

[0029] A fitting hole is formed in the sleeve 2b, into which a second lens group guide bar 13A, both ends of which are held by the front fixed barrel 9 and the rear fixed barrel 11, is slidably fitted. On the opposite side of the sleeve 2b in the Y direction across the second lens group L2, a U-shaped groove 2e for preventing rotation is formed, into which a second lens group guide bar 13B, both ends of which are held by the front fixed barrel 9 and the rear fixed barrel 11, is fitted. The second lens group movement frame 2 is guided in the optical axis direction by the second lens group guide bars 13A and 13B.

[0030] A rack 19 is held by the second lens group movement frame 2. The rack 19 meshes with a lead screw attached to the tip of a stepping motor (not shown). Therefore, when the stepping motor rotates, the second lens group movement frame 2 moves in the optical axis direction via the rack 19.

[0031] The scale holder 2c is formed adjacent to the sleeve 2b, and the reflective scale 17 is adhesively fixed thereto. The reflective scale 17 is disposed in a position adjacent to the rack 19, which is a driving mechanism, so that the position of the second lens group movement frame 2 can be accurately detected. The reflective scale 17 has a length that covers the amount of movement of the second lens group movement frame 2. Therefore, the scale holder 2c has a shape that extends toward the image side in the optical axis direction with respect to the position of the second lens group L2. Also, although only the front end and the rear end of the sleeve 2b are shown in FIG. 3, the sleeve 2b has a predetermined length of a cylinder extending from the front end to the rear end in the optical axis direction in order to suppress the influence of tilting due to play in fitting with the second lens group guide bar 13A.

[0032] Between the sleeve 2b and the scale holding portion 2c and the lens holding portion 2a, a groove is formed that extends parallel to the optical axis direction through which a light-shielding wall formed in the front fixed lens barrel 9 described later passes. The sleeve 2b and the scale holding portion 2c are connected to the lens holding portion 2a by a flange portion 2f formed on the image side in the optical axis direction and a connection portion 2h extending from the flange portion 2f in the optical axis direction. The sleeve 2b, the scale holding portion 2c, and the reflective scale 17 are arranged at a position where light is blocked by the wall of the connection portion 2h in a cross section perpendicular to the optical axis with respect to the optical path passing through the second lens group L2. In addition, a reinforcing portion 2d that connects the sleeve 2b and the lens holding portion 2a is formed extending from the flange portion 2f toward the object side in the optical axis direction over almost the entire length of the sleeve. Since the sleeve 2b and the lens holding portion 2a are connected by the reinforcing portion 2d that extends from the lens holding portion 2a to the flange portion 2f in the optical axis direction, it is possible to suppress the sleeve 2b from falling over with respect to the lens holding portion 2a.

[0033] Next, the light-shielding wall will be described with reference to FIG. 2 and FIG. Fig. 4 shows a perspective view of the front fixed barrel 9. As shown in Fig. 4, a flange portion (first flange portion) 9c is formed on the object side of the front fixed barrel 9 in the optical axis direction. A first light-shielding wall 9a and a second light-shielding wall 9b are formed parallel to the optical axis from the flange portion 9c toward the image side in the optical axis direction. The first light-shielding wall 9a and the second light-shielding wall 9b are formed so as to extend in opposite directions from the inner wall of the front fixed barrel 9 in the circumferential direction.

[0034] As shown in FIG. 2, the first light-shielding wall 9a extending from the inner wall of the side surface of the front fixed lens barrel 9 is disposed inside the scale holding portion 2c and the sleeve 2b (inner diameter side with respect to the optical axis as the center). The second light-shielding wall 9b extending from the inner wall of the lower surface of the front fixed lens barrel 9 to the opposite side in the circumferential direction with respect to the extending direction of the first light-shielding wall 9a is formed inside the sleeve 2b (inner diameter side with respect to the optical axis as the center). In addition, in a cross section perpendicular to the optical axis, the tips of the first light-shielding wall 9a and the second light-shielding wall 9b are formed so as to overlap in the circumferential direction with the optical axis as the center. In other words, in a cross section perpendicular to the optical axis, the first light-shielding wall 9a, the second light-shielding wall 9b and the lens barrel inner wall form an enclosed space (hereinafter, this space is also referred to as the detection unit space) with the overlapping portion being an opening. The first light-shielding wall 9a and the second light-shielding wall 9b are formed from the inner wall of the front fixed barrel 9 toward the inner diameter side, and in a cross section perpendicular to the optical axis, they overlap in the circumferential direction centered on the optical axis and form an overlapping portion spaced apart from each other in the radial direction. At least a portion of each of the first light-shielding wall 9a and the second light-shielding wall 9b overlaps with each other when viewed from the radial direction and is spaced apart from each other in the radial direction. Hereinafter, in this specification, the space formed by the first light-shielding wall 9a, the second light-shielding wall 9b, and the barrel inner wall with the overlapping portion as an opening is also referred to as "a space surrounded by the first light-shielding wall 9a, the second light-shielding wall 9b, and the barrel inner wall in a cross section perpendicular to the optical axis direction."

[0035] In this space, a position detection section (first position detection section) consisting of a reflective scale 17 and an optical sensor 18, and the second lens group guide bar 13A are arranged. Therefore, of the external light OL incident from the object side of the first lens group L1, the light rays directly incident on the inner wall of the lens barrel in the detection section space and the second lens group guide bar 13A can be blocked by the first light-shielding wall 9a and the second light-shielding wall 9b. Therefore, it is possible to prevent the internally reflected stray light from reaching the optical sensor 18.

[0036] There is a gap in the radial direction around the optical axis at the overlapping portion at the tip of the first light-shielding wall 9a and the second light-shielding wall 9b. A reinforcing portion 2d formed on the sleeve 2b is disposed in this gap. In this way, by dividing the light-shielding wall into two and overlapping the tip, a reinforcing portion that suppresses the sleeve 2b from falling over relative to the lens holding portion 2a is formed through the overlapping portion while forming a light-shielding space. Therefore, it is possible to prevent stray light reflected inside the lens barrel from reaching the optical sensor 18 without compromising the strength of the second lens group moving frame 2.

[0037] 5 shows a projection of a light ray L that may enter the detection space through between the first light-shielding wall 9a and the second light-shielding wall 9b onto a cross section perpendicular to the optical axis. As shown in FIG. 5, the direct optical path that may enter the detection space is such that external light does not directly enter the second lens group guide bar 13A. Also, as shown in FIG. 5, the direction in which the gap in the overlapping portion of the first light-shielding wall 9a and the second light-shielding wall 9b extends does not face the direction of the lens in the cross section perpendicular to the optical axis. That is, in the cross section perpendicular to the optical axis direction, the longitudinal direction of the gap in the overlapping portion of the first light-shielding wall 9a and the second light-shielding wall 9b is configured not to intersect with the optical element.

[0038] Fig. 6 shows a cross-sectional view taken along line BB in Fig. 2. In Fig. 6, the upper side is the object side and the lower side is the image side. The optical sensor 18 is fixed to the inner surface of the front fixed lens barrel 9 in the detection space. The reflective scale 17 is fixed to the scale holder 2c of the second lens group movement frame 2 in the detection space so as to face the optical sensor 18.

[0039] In the cross section of Figure 6, the detection space is surrounded (defined) by the object-side flange portion 9c and the image-side flange portion 2f even in the optical axis direction, so that external light does not directly enter the optical sensor 18 and the reflective scale 17 from the first lens group L1 side (upper side in Figure 6).

[0040] In this embodiment, the sleeve 2b and the second lens group guide bar 13A are disposed in the space surrounded by the first and second light-shielding walls 9a and 9b and the inner wall of the front fixed barrel 9, and the reinforcing portion 2d of the sleeve 2b is disposed between the first and second light-shielding walls 9a and 9b, but the present invention is not limited to this configuration. Only the scale holding portion 2c may be disposed in the space surrounded by the first and second light-shielding walls 9a and 9b and the inner wall of the front fixed barrel 9, and the reinforcing portion 2d of the scale holding portion 2c may be disposed between the first and second light-shielding walls 9a and 9b.

[0041] In addition, in a cross section perpendicular to the optical axis, the gap between the first light-shielding wall 9a and the second light-shielding wall 9b is configured to extend in the circumferential direction centered on the optical axis position, and does not extend toward the lens. That is, in a cross section perpendicular to the optical axis, the lens is not located on the extension of the gap between the first light-shielding wall 9a and the second light-shielding wall 9b, and the second lens group guide bar 13A is not located on the extension of the gap on the detection space side. Therefore, even if there is external light that enters the detection space through the gap, it is reflected multiple times by the inner wall of the lens barrel and becomes attenuated light. Therefore, even if the external light that has entered the detection space subsequently reaches the optical sensor 18, the intensity is weakened, so deterioration of position detection can be suppressed.

[0042] FIG. 7 shows a cross-sectional view of the reset detection section (second position detection section) that detects the reference position in the position detection of the second lens group moving frame 2. The front fixed lens barrel 9 holds a photointerrupter 20 as a reset detection section. The second lens group moving frame 2 is formed with a reset light-shielding protrusion 2g. When the second lens group moving frame 2 moves in the optical axis direction, the reset light-shielding protrusion 2g passes between the photointerrupters 20, switching between a light-shielding state and a light-transmitting state, and resetting the number of pulses of the stepping motor. As shown in FIG. 7, the photointerrupter 20 is disposed in a detection section space surrounded by the first light-shielding wall 9a and the second light-shielding wall 9b. Therefore, it is possible to prevent external light OL incident from the object side of the first lens group L1 from reaching the light-receiving section of the photointerrupter 20, which would deteriorate the reset detection accuracy.

[0043] 6, the optical sensor 18 and the photointerrupter 20 are disposed in a detection space surrounded by the flange portions 9c and 2f not only in the radial direction about the optical axis but also in the optical axis direction. Therefore, it is possible to prevent the light emitted from the light emitting portion of the optical sensor 18 and the photointerrupter 20 from reflecting inside the lens barrel including the second lens group guide bar 13A and reaching the imaging element and affecting the captured image.

[0044] As described above, the lens barrel of the present invention can provide a lens device that suppresses deterioration in the accuracy of lens position detection by optical position detection and prevents malfunction of lens drive control.

[0045] Furthermore, a lens device having the lens barrel of the present invention can be realized that can enjoy the effects of the lens barrel of the present invention. Furthermore, an imaging device having the lens barrel of the present invention and an imaging device having an imaging element that captures an image formed by the lens device can be realized that can enjoy the effects of the lens barrel of the present invention.

[0046] The disclosure of this embodiment includes the following configuration. (Configuration 1) a movable lens barrel that holds an optical element and is movable in the direction of an optical axis; a fixed barrel that holds the movable barrel; a first position detection unit including a detector provided on one of the movable barrel or the fixed barrel, and a detected object provided on the other of the movable barrel or the fixed barrel; a first light-shielding wall and a second light-shielding wall are formed on an inner wall of the fixed barrel, At least a portion of each of the first light-shielding wall and the second light-shielding wall overlaps with each other when viewed in a radial direction and is spaced apart from each other in the radial direction, An optical device characterized in that the first position detection unit is arranged in a space surrounded by the first light-shielding wall, the second light-shielding wall, and an inner wall of the fixed barrel in a cross section perpendicular to the optical axis. (Configuration 2) the fixed barrel has a guide bar extending in the optical axis direction, the movable barrel has a guide sleeve into which the guide bar is slidably fitted, The guide sleeve and the guide bar are disposed in the space, The optical device described in configuration 1, characterized in that the guide sleeve is connected to a reinforcing portion extending along the length of the guide sleeve in the optical axis direction through at least a portion of the gap between the first light-shielding wall and the second light-shielding wall. (Configuration 3) the movable lens barrel has a holder for holding one of the detector or the detected object, 3. The optical device according to configuration 2, wherein the holding portion is fixed to the reinforcing portion. (Configuration 4) the fixed barrel has a first flange portion that is connected to one end of the first light-shielding wall and one end of the second light-shielding wall in the optical axis direction and extends from an inner wall of the fixed barrel toward an inner diameter side, the movable barrel has, on an image side, a second flange portion that is connected to the other end of the reinforcing portion in the optical axis direction and extends in a plane perpendicular to the optical axis, 4. The optical device according to claim 2, wherein an end of the space in the optical axis direction is defined by the first flange portion and the second flange portion. (Configuration 5) the fixed barrel has a first flange portion that is connected to one end of the first light-shielding wall and one end of the second light-shielding wall in the optical axis direction and extends from an inner wall of the fixed barrel toward an inner diameter side, The optical device described in any one of configurations 2 to 4, characterized in that the movable barrel has a second flange portion on the image side that connects to the other end of the reinforcing portion in the optical axis direction and extends in a plane perpendicular to the optical axis. (Configuration 6) 6. The optical device according to any one of configurations 1 to 5, further comprising a second position detector disposed in the space and detecting a reference position of the movable barrel. (Configuration 7) The optical device described in any one of configurations 1 to 6, characterized in that in a cross section perpendicular to the optical axis, the longitudinal direction of at least a portion of the gap between the first light-shielding wall and the second light-shielding wall does not intersect with the optical element. (Configuration 8) The optical device according to any one of configurations 1 to 7, wherein the optical element is a lens. (Configuration 9) An imaging device including the optical device according to any one of configurations 1 to 8, and an imaging element that receives an image formed by the optical device. [Explanation of symbols]

[0047] 100: Lens barrel (optical device) L2: Second lens group (optical element) 2: Second lens group moving frame (moving barrel) 9: Front fixed tube (fixed tube) 9a: 1st light shielding wall 9b:Second light shielding wall 17: Reflective scale (detector, first position detection unit) 18: Optical sensor (optical detector, first position detection unit)

Claims

1. a movable lens barrel that holds an optical element and is movable in the direction of an optical axis; a fixed barrel that holds the movable barrel; a first position detection unit including a detector provided on one of the movable barrel or the fixed barrel, and a detected object provided on the other of the movable barrel or the fixed barrel; a first light-shielding wall and a second light-shielding wall are formed on an inner wall of the fixed barrel, At least a portion of each of the first light-shielding wall and the second light-shielding wall overlaps with each other when viewed in a radial direction and is spaced apart from each other in the radial direction, An optical device characterized in that the first position detection unit is arranged in a space surrounded by the first light-shielding wall, the second light-shielding wall and an inner wall of the fixed barrel in a cross section perpendicular to the optical axis.

2. the fixed barrel has a guide bar extending in the optical axis direction, the movable barrel has a guide sleeve into which the guide bar is slidably fitted, The guide sleeve and the guide bar are disposed in the space, The optical device according to claim 1, characterized in that the guide sleeve is connected to a reinforcing portion extending through at least a portion of the gap between the first light-shielding wall and the second light-shielding wall over the length of the guide sleeve in the optical axis direction.

3. the movable lens barrel has a holder for holding either the detector or the detected object, The optical device according to claim 2 , wherein the holding portion is fixed to the reinforcing portion.

4. the fixed barrel has a first flange portion that is connected to one end of the first light-shielding wall and one end of the second light-shielding wall in the optical axis direction and extends from an inner wall of the fixed barrel toward an inner diameter side, the movable barrel has, on an image side, a second flange portion that is connected to the other end of the reinforcing portion in the optical axis direction and extends in a plane perpendicular to the optical axis, The optical device according to claim 2 , wherein both ends of the space in the optical axis direction are defined by the first flange portion and the second flange portion.

5. the fixed barrel has a first flange portion that is connected to one end of the first light-shielding wall and one end of the second light-shielding wall in the optical axis direction and extends from an inner wall of the fixed barrel toward an inner diameter side, 3. The optical device according to claim 2, wherein the movable barrel has a second flange portion on the image side, the second flange portion being connected to the other end of the reinforcing portion in the optical axis direction and extending in a plane perpendicular to the optical axis.

6. 2. The optical device according to claim 1, further comprising a second position detector disposed in the space and detecting a reference position of the movable lens barrel.

7. 2 . The optical device according to claim 1 , wherein a longitudinal direction of the gap between the first light-shielding wall and the second light-shielding wall does not intersect with the optical element in a cross section perpendicular to the optical axis.

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

9. An imaging device comprising the optical device according to claim 1 and an imaging element that receives an image formed by the optical device.

Images