JP2012042558A - Filter switch-over unit and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To interrupt infrared rays coming incident on an image pickup element from a photo-interrupter even if infrared cut filter switch-over is manually accomplished.SOLUTION: A filter switch-over unit 8 that causes an infrared cut filter 37 to move into and out of a path of light coming incident from photographic optical systems L1 to L4 on an image pickup element 41, a filter frame having a rail 43 and so configured as to be turnable while holding the infrared cut filter, an IR reset 39 having a transmissive photo-interrupter that detects the position of the filter frame, an image pickup element holder 38 that has a rail 47 sliding in contact with the rail 43 over the turning range of the filter frame and holding the image pickup element, wherein the rail 47 has a part protruding farther out than a light emitting part of the transmissive photo-interrupter in the direction of the optical axes of the photographic optical systems and, when the infrared cut filter is off the optical path, the rails 43 and 47 interrupt the light coming incident from the transmissive photo-interrupter on the image pickup element.

Description

  The present invention relates to a filter switching unit having an infrared cut filter (hereinafter sometimes referred to as an “IR cut filter”) and an imaging apparatus.

  In an imaging device equipped with an infrared cut filter and a photo interrupter that detects its position, infrared light from the photo interrupter enters the image sensor when the infrared cut filter is out of the optical path of light from the imaging optical system to the image sensor. It is necessary not to do.

  Therefore, Patent Document 1 has a mechanism that supports the infrared cut filter so as to be able to move forward and backward in the optical path of light incident on the image sensor, and turns off the light emitting portion of the photo interrupter when the infrared cut filter is located at the retracted position. The proposed imaging device is proposed.

JP 2008-131562 A

  In Patent Document 1, since the infrared cut filter is driven and switched by an actuator, the light-emitting portion of the photo interrupter can be turned off according to the driving state of the actuator (that is, according to the position of the infrared cut filter). is there. However, in the case of a lens barrel in which the infrared cut filter is switched by manual driving, there is a problem that the timing for turning off the photo interrupter is unknown and cannot be handled.

  Accordingly, the present invention provides an exemplary object of providing a filter switching unit and an imaging apparatus that can block infrared light incident on an image sensor from a photo interrupter even when the infrared cut filter is manually switched. And

  The filter switching unit of the present invention is a filter switching unit for moving the infrared cut filter back and forth in the optical path of light incident on the image sensor from the photographing optical system, and has a first rail and holds the infrared cut filter. A filter holding portion configured to be rotatable, a transmissive photo interrupter for detecting the position of the filter holding portion, and a first slide that contacts and slides on the first rail over a range in which the filter holding portion rotates. An image sensor holding unit that holds the image sensor, and the second rail is closer to the object side than the light emitting unit of the transmissive photo interrupter in the optical axis direction of the photographing optical system. And when the infrared cut filter is out of the optical path, the first rail and the second rail are the transmissive photointerrupter. Characterized by shielding light incident on the imaging element from the data.

  According to the present invention, it is possible to provide a filter switching unit and an image pickup apparatus that can block infrared light incident on an image pickup device from a photo interrupter even when the infrared cut filter is manually switched.

It is a fragmentary sectional view in night mode of the filter switching unit of an imaging device. Example 1 It is a fragmentary sectional view of the imaging device shown in FIG. Example 1 It is a fragmentary sectional view of the imaging device shown in FIG. Example 1 FIG. 2 is a partially exploded perspective view of the imaging apparatus illustrated in FIG. 1. Example 1 It is a disassembled perspective view of the filter switching unit shown in FIG. Example 1 It is a top view of the filter switching unit shown in FIG. Example 1 FIG. 2 is a plan view of the filter switching unit shown in FIG. 1 in a day mode. Example 1 It is BB 'sectional drawing of FIG. Example 1 It is a top view of the filter switching unit shown in FIG. 1 immediately after switching from day mode to night mode. Example 1 It is CC 'sectional drawing of FIG. Example 1 It is a block diagram of the imaging device shown in FIG. Example 1 It is a disassembled perspective view of a filter switching unit. (Example 2) It is a top view of the filter switching unit shown in FIG. (Example 2) It is DD 'sectional drawing of FIG. (Example 2) FIG. 13 is a plan view of the filter switching unit shown in FIG. 12 in the day mode. (Example 2) It is EE 'sectional drawing of FIG. (Example 2)

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 2 is a partial cross-sectional view (XZ cross-sectional view) of the vicinity of the lens barrel 1 of the image pickup apparatus (video camera or the like) according to the first embodiment. FIG. 3 is a partial cross-sectional view (XY cross-sectional view) in the vicinity of the lens barrel 1 of the image pickup apparatus according to the first embodiment. FIG. 4 is an exploded perspective view of the lens barrel 1 of the imaging apparatus according to the first embodiment. In each figure, the X-axis direction is defined as a direction parallel to the optical axis, the Y-axis is defined as a vertical direction orthogonal to the optical axis direction, and the Z-axis is defined as a horizontal direction orthogonal to the optical axis direction.

  2 to 4, the lens barrel 1 has a four-group lens composed of L1 to L4, and has a photographing optical system that forms an optical image of a subject.

  L1 is a first lens unit. L2 is a second lens unit that moves in the optical axis direction and performs zooming. L3 is a third lens unit that shifts in a direction orthogonal to the optical axis of the photographing optical system (hereinafter referred to as an optical axis orthogonal direction) to reduce image blur and move in the optical axis direction. L4 is a fourth lens unit that moves in the optical axis direction to adjust the focus.

  Reference numeral 2 denotes a first lens frame that holds the first lens unit L1. Reference numeral 3 denotes a variator moving frame that holds the second lens unit L2. Reference numeral 4 denotes a shift unit that holds the third lens unit L3. Reference numeral 5 denotes a focus movement frame that holds the fourth lens unit L4. Reference numeral 6 denotes a fixed barrel, and 7 denotes a rear barrel. The fixed lens barrel 6 has a rear end coupled to the rear lens barrel 7 and a front end fixed to the first lens frame 2 in order to fix the first lens unit L1 at a predetermined position.

  Reference numerals 9 a and 9 b denote a first guide bar and a second guide bar, both ends of which are held by the fixed barrel 6 and the rear barrel 7. The third guide bar 10, the fourth guide bar (not shown), the fifth guide bar 11, and the sixth guide bar 11b are held at both ends by the rear barrel 7, the image sensor holder 7, and a filter switching unit 8A described later. Yes.

  The variator moving frame 3 is supported by the first and second guide bars 9a and 9b so as to be movable in the optical axis direction. The shift unit 4 is supported by a third guide bar 10 and a fourth guide bar (not shown) so as to be movable in the optical axis direction, and is fixed to the rear barrel 7.

  A light amount adjusting unit 12 changes the light amount incident on the photographing optical system and is fixed to the rear barrel 7. The aperture diameter is changed by moving two or more aperture blades in the direction perpendicular to the optical axis. Further, the light quantity adjustment unit 12 is configured such that a gradation ND filter (not shown) can advance and retreat with respect to the optical path independently of the aperture blade. The focus moving frame 5 is supported by the fifth and sixth guide bars 11a and 11b so as to be movable in the optical axis direction.

  A stepping motor 13 drives the variator moving frame 3 in the optical axis direction and is fixed to the rear barrel 6. A lead screw 14 is formed on the output shaft of the stepping motor 13. Since the rack 15 attached to the variator moving frame 3 is engaged with the lead screw 14, the variator moving frame 3 is driven in the optical axis direction when the stepping motor 13 is energized and the lead screw 14 rotates.

  Reference numeral 16 denotes a zoom reset for detecting the reference position of the variator moving frame 3, which detects the switching between the light shielding state and the light transmitting state due to the movement of the light shielding portion 207 formed in the variator moving frame 3 in the optical axis direction. It is comprised by the photointerrupter.

  The zoom reset 16 is fixed to the rear barrel 7 via the substrate. The variator moving frame 3 holds a sensor magnet 17 that is multipolarly magnetized in the direction of the optical axis, and a line of magnetic force accompanying the movement of the sensor magnet 17 is located at a position facing the sensor magnet 17 of the rear barrel 7. An MR sensor 18 for reading the change is fixed. By using the signal from the MR sensor 18, it is possible to detect the amount of movement of the variator moving frame 3, that is, the second lens unit L2, from a predetermined reference position.

  A stepping motor 19 drives the shift unit 4 in the optical axis direction and is fixed to the rear barrel 7. A lead screw 20 is formed on the output shaft of the stepping motor 19. Since a shift rack (not shown) attached to the shift unit 4 is engaged with the lead screw 20, when the stepping motor 19 is energized and the lead screw 20 rotates, the shift unit 4 is driven in the optical axis direction.

  Reference numeral 21 denotes a zoom reset for detecting the reference position of the shift unit 4, which is a photo for detecting the switching between the light shielding state and the light transmitting state due to the movement of the light shielding portion 22 formed in the shift unit 4 in the optical axis direction. It is composed of interrupters. The zoom reset 21 is fixed to the rear barrel 7 via the substrate. Further, switching between the zoom reset 21 and the light shielding / transmission state of the light projecting unit 22 is set to be detected when the shift unit 4 is within the movable range and outside the movable range of the focus moving frame 5. ing.

  Reference numeral 22 denotes a shift holding frame that holds the third lens unit L3. The shift holding frame 22 holds two shift drive magnets 23 and a first yoke 24 for closing the magnetic path of the magnets.

  A shift base 25 serves as a base member of the shift unit 4 and holds a shift coil 26 and a second yoke 27 for closing the magnetic path of the shift drive magnet 23. When the shift coil 26 is energized, a driving force is generated in the shift magnet, and the third lens unit L3 moves relative to the shift holding frame 22 in a direction perpendicular to the optical axis. There are two sets each of the shift drive magnet 23, the first yoke 24, the second yoke 27, and the shift coil 26, and these portions serve as shift drive actuator portions.

  In FIG. 2, with respect to the optical axis center, a pitch direction driving shift drive actuator portion is provided in the −Z direction, and a yaw driving shift drive actuator portion is provided in the Y direction. Since there are two sets of shift drive units, the third lens unit L3 can be driven in any direction within a plane perpendicular to the optical axis.

  The shift coil 26 is soldered to the shift flexible board 46 so as to be electrically conductive. The shift flexible substrate 28 is fixed to a stopper (not shown) provided in the rear lens barrel 7 and is connected to the shift unit 4 via a U-turn shape 28a provided in the lens barrel. The U-turn shape 47 has a shape that prevents the reaction force of the flexible substrate key from being applied to the shift unit 4 when the shift unit 4 moves in the optical axis direction.

  Reference numerals 29, 30, and 31 denote a drive coil, a drive magnet, and a yoke member for closing a magnetic flux constituting a focus motor (voice coil motor) that drives the fourth lens unit L4 in the optical axis direction.

  The drive coil 29 is attached to the focus movement frame 4. The drive magnet 30 is provided in the yoke member 31, and the yoke member 31 is attached to the filter switching unit 8A. Here, when a current is passed through the drive coil 29, a Lorentz force is generated due to repulsion between the lines of magnetic force generated between the magnet 30 and the drive coil 29, and the fourth lens unit L4 moves in the optical axis direction together with the focus moving frame 5. Driven.

  The focus moving frame 5 holds a sensor magnet 32 magnetized in a multipolar manner in the optical axis direction, and a magnetic field line accompanying the movement of the sensor magnet 32 is located at a position facing the sensor magnet 32 in the rear barrel 7. An MR sensor 33 for reading the change is fixed. By using the signal from the MR sensor 33, the amount of movement of the focus movement frame 5, that is, the fourth lens unit L4 from the predetermined reference position can be detected. The focus moving frame 5 is energized to the coil, moves in the −X direction parallel to the subject side, that is, the optical axis, and detects a state in which the focus moving frame 5 is in contact with the mechanical end as a reference position.

  In a state where the coil 29 is energized (hereinafter referred to as an energized state), Lorentz force is generated and the focus moving frame 5 is moved in the optical axis direction. On the other hand, in a state where the coil 29 is not energized (hereinafter referred to as a non-energized state), the driving force to the focus moving frame 5 is not generated, and the focus moving frame 5 itself does not have a self-holding force. . Here, the “self-holding force” is a force capable of stopping the movable coil 29 and further the focus moving frame 5 provided with the coil 29 on the spot in a non-energized state.

  The drive coil 29 is soldered to the focus flexible substrate 34 and is configured to be electrically conductive. Further, the focus flexible substrate 34 is fixed to a not-shown stopper provided in the rear lens barrel 7 and is fixed to the focus moving frame 5 via a U-turn shape 34a provided in the lens barrel. The coil 29 is connected.

  8A is a filter switching unit that switches between the night mode and the day mode by moving the infrared cut filter back and forth in the optical path of the light incident on the image sensor from the photographing optical system. Here, the “night mode” is a mode for irradiating the image sensor 41 with infrared rays for dark place photography, and the “day mode” is a mode for not irradiating infrared rays.

  FIG. 5 is an exploded perspective view of the filter switching unit 8A. FIG. 6 is a plan view of the night-mode filter switching unit 8A as viewed from the object side, and the IR base 35 is not displayed. 1 is a cross-sectional view taken along the line AA ′ of FIG.

  FIG. 7 is a plan view of the day-mode filter switching unit 8A as viewed from the object side, and the IR base 35 is not displayed. 8 is a cross-sectional view taken along the line BB ′ of FIG.

  FIG. 9 is a plan view of the filter switching unit 8A viewed from the object side at the moment when the light-shielding wall 36c starts to shield light emitted from the photo interrupter after switching to the night mode, and the IR base 35 and the infrared cut filter 37 are not displayed. It is said. 10 is a cross-sectional view taken along the line CC ′ of FIG.

  1 and 5 to 10, the filter switching unit 8 </ b> A includes an IR base 35, a filter frame 36, an infrared cut filter 37, an image sensor holder 38, an IR reset 39, a drive unit 40, and an image sensor 41.

  The IR base 35 includes an outer wall 35a indicated by a dotted line in FIGS. 1, 8, and 10, and an opening 44 and a convex rail 46 on the optical axis. The outer wall 35a includes the surface of the IR base 35 on the image sensor side.

  A filter frame (filter holding unit) 36 holds an infrared cut filter 37 and is rotatable by being sandwiched between an IR base 35 provided on the subject side (object side) and an image pickup device holder 38 provided on the image pickup device side. It is configured. The filter frame 36 has a convex rail 42 on the object side, and has a convex rail 43 (first rail) on the image sensor side. The rail 42 is in contact with and opposed to the rail 46.

  The filter frame 36 includes a long hole portion 36a, a perfect circle portion 36b, and a light shielding wall 36c. The light shielding wall 36c shields light from a light emitting portion 49 (to be described later) of the IR reset 39 from the light receiving portion 48 in the night mode.

  The imaging element holder (imaging element holding unit) 38 holds the imaging element 41, a projection 38a inserted into the perfect circle part 36b, an opening 45 and a convex rail 47 (second rail) on the optical axis. And having. The rail 43 is in contact with the rail 47 in opposition. Since the rail 47 has a portion that protrudes closer to the object side than a light emitting portion 49 of an IR reset 39 to be described later in the optical axis direction of the photographing optical system, the light from the light emitting portion 49 can be shielded.

  The IR reset 39 is an element that detects the position of the filter frame 36 and includes a transmissive photo interrupter having a light receiving unit 48 and a light emitting unit 49. The IR reset 39 is attached to the image sensor holder 38 such that the light receiving unit 48 is on the IR base 35 side and the light emitting unit 49 is the image sensor holder 38, and is arranged adjacent to the rails 46 and 47 in a YZ plane. Yes. Since the drive unit 40 of this embodiment is not automatic but manual, the timing for turning off the photo interrupter is not known as in Patent Document 1, and thus the light emitting unit 49 emits infrared light regardless of the position of the filter frame 36. It always emits light.

  The image sensor 41 converts an optical image captured by the imaging optical system into an electrical signal, and is attached to the X direction side of the opening 45 on the optical axis.

  The drive unit 40 is connected to a connecting member (not shown) outside the lens barrel 1, and when the connecting member is displaced by a manual operation, the arm 40a on the driving arm moves. The arm 40 a is inserted into the long hole portion 36 a of the filter frame 36.

  When the drive unit 40 is rotationally driven, the arm 40a rotates the filter frame 36 around the perfect circle part 36b while the rails 42, 46 and the rails 43, 47 contact and slide. Since the rails 46 and 47 are provided over the sliding range, the rails 42 and 46 and the rails 43 and 47 always come into contact with each other and slide when the filter holding frame 36 rotates.

  As shown in FIG. 6, the night mode is when the infrared cut filter 37 is removed from the opening 45, and the day mode is when the infrared cut filter 37 is on the opening 45 as shown in FIG.

  In the night mode, the light shielding wall 36c is located between the light emitting portion 49 and the light receiving portion 48 to shield light from the light emitting portion 49 to the light receiving portion 48. In the day mode, the light shielding wall 36c is separated from between the light emitting portion 49 and the light receiving portion 48. The light from the light emitting unit 49 enters the light receiving unit 48 without blocking the light.

  Light that is about to enter the image sensor 41 from the light emitting unit 49 is captured after the direct light R1 that directly enters the image sensor 41 from the light emitting unit 49 and the light from the light emitting unit 49 is reflected by the outer wall 35a of the IR base 35. There is reflected light R2 incident on the element 41. In the present embodiment, a light shielding unit for preventing the infrared light from the light emitting unit 49 from entering the image sensor 41 is provided.

  In the day mode, as shown in FIGS. 7 and 8, the direct light R <b> 1 is blocked by the rail 43 from the light emitting unit 49. The reflected light R <b> 2 is shielded by the infrared cut filter 37 because the infrared cut filter 37 is on the image sensor 41.

  On the other hand, in the night mode, as shown in FIGS. 1 and 6, light from the light emitting unit 49 is blocked by the rails 43 and 47, so that light incident on the image sensor 41 from the light emitting unit 49 is blocked.

  As shown in FIGS. 9 and 10, in the middle of switching from the day mode to the night mode, when the light shielding wall 36 c starts to shield light from the light emitting unit 49 to the light receiving unit 48, the reflected light from the IR base 35 is reflected by the opening 45. Is shielded by the infrared cut filter 37 and the filter frame 36. Thereby, the reflected light does not enter the image sensor 41.

  FIG. 11 is a block diagram of an imaging apparatus having the lens barrel of the first embodiment. In FIG. 11, the light from the subject passes through the lens group in the lens barrel 1 and enters the image sensor 41 during shooting. Incident light is photoelectrically converted to a processing signal 50, passes through an AF gate 51 as a digital signal, is input to the CPU 54 after performing AF signal processing 52 and the like. When the zoom switch 53 functions, the lens units L2, L3, and L4 are moved in the optical axis direction by the coil 29 and the stepping motors 13 and 19 based on the signal input to the CPU.

  The imaging apparatus according to the second embodiment is different from the first embodiment in that it includes a filter switching unit 8B having a rail shape different from that of the filter switching unit 8A, and the other configurations are common.

  FIG. 12 is an exploded perspective view of the filter switching unit 8B. FIG. 13 is a plan view of the night-mode filter switching unit 8B as viewed from the object side, and the IR base is not displayed. 14 is a cross-sectional view taken along the line DD ′ of FIG. FIG. 15 is a plan view of the day-mode filter switching unit 8B as viewed from the object side, and the IR base is not displayed. 16 is a cross-sectional view taken along the line EE ′ of FIG.

  12 to 16, the filter switching unit 8B includes an IR base 55, a filter frame 56, an infrared cut filter 57, an image sensor holder 58, an IR reset 59, a drive unit 60, and an image sensor 61.

  The IR base 55 includes an outer wall 55a indicated by a dotted line in FIGS. 14 and 16, and an opening 65 and a convex rail 66 on the optical axis. The outer wall 55a includes the surface of the IR base 55 on the image sensor side.

  The filter frame (filter holding unit) 56 holds the infrared cut filter 57 and is sandwiched between an IR base 55 provided on the subject side (object side) and an image sensor holder 58 provided on the image sensor side. The filter frame 56 has a convex rail 62 (first rail) on the object side, and a concave rail 63 (second rail) on the image sensor side. The rail 62 is opposed to and in contact with the rail 66.

  The filter frame 36 includes a long hole portion 56a, a perfect circle portion 56b, and a light shielding wall 56c. The light blocking wall 56c blocks light from a light emitting unit 59 (to be described later) of the IR reset 59 to the light receiving unit 58 in the night mode.

  The image pickup device holder (image pickup device holding portion) 58 holds the image pickup device 61, and includes a protrusion 58a inserted into the perfect circle portion 56b, and an opening 65 and a convex rail 67 on the optical axis. The rail 63 faces and contacts the rail 67.

  The IR reset 59 is an element that detects the position of the filter frame 56 and is a transmissive photo interrupter having a light receiving portion 68 and a light emitting portion 69. The IR reset 59 is attached to the image sensor holder 58 so that the light receiving unit 68 is on the IR base 55 side and the light emitting unit 69 is the image sensor holder 58, and is arranged adjacent to the rails 66 and 67 in a YZ plane. Yes.

  The image sensor 61 converts an optical image photographed by the photographing optical system into an electrical signal, and is attached to the X direction side of the opening 65 on the optical axis.

  The drive unit 60 is connected to a connection member (not shown) outside the lens barrel 1, and when the connection member is displaced by a manual operation, the arm 60a on the drive arm moves. The arm 60 a is inserted into the long hole portion 56 a of the filter frame 56.

  When the drive unit 60 is rotationally driven, the arm 60a rotates the filter frame 56 around the perfect circle part 56b while the rails 62, 66 and the rails 63, 67 are in contact with each other. Since the rails 66 and 67 are all around the sliding range, the rails 62 and 66 and the rails 63 and 67 always rotate while being in contact with each other.

  As shown in FIG. 13, the night mode is when the infrared cut filter 57 is removed from the opening 45, and the day mode is when the infrared cut filter 57 is on the opening 65 as shown in FIG.

  In the night mode, the light shielding wall 56c is located between the light emitting unit 69 and the light receiving unit 68 and blocks light from the light emitting unit 69 to the light receiving unit 68. The light from the light emitting unit 69 enters the light receiving unit 68 without blocking the light.

  Light that is about to enter the image sensor 61 from the light emitting unit 69 is captured after the direct light R1 that directly enters the image sensor 61 from the light emitting unit 69 and the light from the light emitting unit 69 is reflected by the outer wall 55a of the IR base 55. There is reflected light R2 incident on the element 61. Also in this embodiment, a light shielding unit for preventing the infrared light from the light emitting unit 69 from entering the image sensor 61 is provided.

  In the day mode, the direct light R1 is blocked by the rail 63 from the light emitting portion 69, as shown in FIGS. The reflected light R <b> 2 is shielded by the infrared cut filter 57 because the infrared cut filter 57 is on the image sensor 61.

  On the other hand, in the night mode, as shown in FIGS. 13 and 14, light from the light emitting unit 69 is blocked by the rails 63 and 67, so that light incident on the image sensor 61 from the light emitting unit 69 is blocked.

  Unlike the first embodiment, the second embodiment has a nested shape in which the rail 67 is inserted into the rail 63. Therefore, the rail 67 can be made longer than the rail 67 of the first embodiment on the object side. Therefore, it becomes easy to block the direct light incident on the image sensor 61 from the light emitting unit 69 in the day mode. Even in the night mode, in Example 1, there is a slight gap between the rails 43 and 47 during driving due to vibration or the like, and light from the light emitting unit 69 may leak slightly from there. This reduces the possibility.

  Similarly to the first embodiment, during the switching from the day mode to the night mode, the reflected light from the IR base 55 passes through the opening 65 when the light shielding wall 56c starts to shield the light from the light emitting unit 69 to the light receiving unit 68. Light is shielded by the infrared cut filter 57 and the filter frame 56. Thereby, the reflected light does not enter the image sensor 61.

  As mentioned above, although the preferable Example of this invention was described, this invention is not limited to these Examples, A various deformation | transformation and change are possible within the range of the summary.

  The imaging device can be applied to use for imaging a subject.

8A, 8B Filter switching unit 35, 55 IR base 36, 56 Filter frame (filter holding unit)
37, 57 Infrared cut filter 38, 58 Image sensor holder (image sensor holder)
39, 59 IR reset (transmission type photo interrupter)
41, 61 Image sensor 43, 63 Rail (first rail)
47, 67 rail (second rail)

Claims (6)

A filter switching unit for moving the infrared cut filter back and forth in the optical path of light incident on the image sensor from the imaging optical system,
A filter holding unit having a first rail and configured to hold and rotate the infrared cut filter;
A transmissive photo interrupter for detecting the position of the filter holding unit;
An image sensor holding unit that holds the image sensor, and has a second rail that slides in contact with the first rail over a range in which the filter holder rotates.
Have
The second rail has a portion that protrudes closer to the object side than the light emitting portion of the transmissive photointerrupter in the optical axis direction of the photographing optical system, and the second rail when the infrared cut filter is out of the optical path. The filter switching unit, wherein one rail and the second rail block light incident on the image sensor from the transmissive photo interrupter.   2. The light emitting device according to claim 1, wherein when the infrared cut filter is inserted in the optical path, the first rail blocks light incident directly on the image sensor from the transmissive photo interrupter. Filter switching unit.   The filter switching according to claim 1 or 2, wherein the first rail has a concave shape, and the second rail has a convex shape in cross section and is inserted into the first rail. unit.   4. The apparatus according to claim 1, wherein the imaging element is covered with the infrared cut filter and the filter holding unit when the infrared cut filter is being removed from the optical path. 5. The filter switching unit described.   The filter switching according to any one of claims 1 to 4, wherein the transmissive photo interrupter emits light regardless of a position of the infrared cut filter, and the filter holding unit is manually rotated. unit.   An image pickup apparatus comprising the filter switching unit according to claim 1.