JP6790434B2 - Imaging device - Google Patents

Description

The present invention relates to an image pickup apparatus, and more particularly to an image pickup apparatus provided with a shock absorbing mechanism of a movable mirror.

In a single-lens reflex camera, which is an imaging device having a movable mirror (quick return mirror), when observing a subject through the finder optical system, the movable mirror is positioned on the optical path of the photographing optical system to direct the subject light to the finder optical system side. When shooting (exposure), the movable mirror is retracted from the optical path of the shooting optical system. The former position on the optical path of the photographing optical system is defined as the finder light guide position of the movable mirror, and the latter position retracted from the optical path of the photographing optical system is defined as the retracted position of the movable mirror.

Inside the single-lens reflex camera, there is a movement control unit that contacts the movable mirror when it reaches the finder light guide position or the retracted position and regulates further movement, and the movable mirror that operates at high speed moves. There is a risk of vibration due to impact when contacting the regulation part. The vibration of the movable mirror at the finder light guide position causes the subject image to fluctuate when observed by the finder optical system. In addition, in a single-lens reflex camera of the type that guides the subject light to the focal length detection device or the photometric sensor using the movable mirror in the finder light guide position, while the movable mirror is vibrating in the finder light guide position It is not possible to accurately determine the in-focus state or measure the light. The vibration of the movable mirror at the retracted position causes the camera to shake during exposure and delay the exposure operation. In order to alleviate these problems, various shock absorption mechanisms that suppress the vibration of the movable mirror have been proposed. For example, Patent Document 1 and Patent Document 2 describe a shock absorbing mechanism that suppresses vibration of a movable mirror at a retracted position.

Japanese Patent No. 5849458 Japanese Unexamined Patent Publication No. 2014-145878

In the single-lens reflex camera described in Patent Document 1, a shock absorbing mechanism is provided on the side of a mirror box in which a movable mirror is provided. In addition to the shock absorbing mechanism of the movable mirror, the mirror box supports a drive mechanism for driving the movable mirror and a mechanism for shutter charging, and the components of the finder optical system are also supported on the upper part of the mirror box. .. In recent years, image sensors (imaging elements) used in single-lens reflex cameras have become larger, and the finder optical system has tended to become larger accordingly. Then, there arises a problem that it becomes difficult to secure a space for arranging the shock absorbing mechanism for the retracted position that suppresses the vibration of the movable mirror at a position close to the finder optical system in the mirror box.

In the single-lens reflex camera described in Patent Document 2, a screen holding member that holds a focusing screen (focus plate) is rotatably supported by a screen base that is a fixing member, and is rotated coaxially with the screen holding member. It is equipped with a mirror-up cushioning material holder. The cushioning material unit is fixed to the screen base, and the mirror-up cushioning material is held in the mirror-up cushioning material holder. When the movable mirror rotates to the retracted position, the movable mirror abuts on the mirror-up cushioning material held in the mirror-up cushioning material holder, and the mirror-up cushioning material holder rotates slightly and abuts on the cushioning material unit. Absorbs the impact from the movable mirror. In the shock absorbing mechanism of Patent Document 2, the cushioning material unit that finally absorbs the shock is arranged by utilizing the space in front of the focusing screen, but the shock absorbing mechanism from the movable mirror to the cushioning material unit is used. As a structure, a mirror-up cushioning material holder, which is a rotating member long in the optical axis direction of the optical system for photographing, is used, and there is a problem that the size becomes large as a whole. Further, the screen base is fixed to the upper part of the mirror box, and the mirror lockup cushioning material holder is rotatably supported with respect to the screen base. Therefore, the structure is substantially the same as that of the mirror lockup cushioning material holder supported by the mirror box, and the support of the mirror lockup cushioning material holder has the same problems as in Patent Document 1 described above.

The present invention has been made in view of the above problems, and has a simple and space-efficient configuration, and can absorb shocks when the movable mirror moves to the retracted position side approaching the finder optical system. It is an object of the present invention to provide an image pickup apparatus.

The present invention has a first position that is located on the optical path of the photographing optical system and reflects the subject light to the observation optical system, and a second position that allows the subject light to pass through the photographing light receiving portion without being reflected. A movable mirror that can be moved to, a focus plate that constitutes the observation optical system, a focus plate support member that supports the focus plate, and the movable mirror when the movable mirror moves from the first position to the second position. In an imaging device provided with a mirror shock absorbing member that abuts and absorbs a shock, the mirror shock absorbing member is located on the subject side from the center of the focus plate in the direction along the optical axis of the photographing optical system and is in focus. the thickness movably focusing plate support member in the direction of the plate that have been supported.

In addition, a moving support mechanism that movably supports the mirror shock absorbing member with respect to the focus plate support member in the thickness direction of the focus plate is provided on the subject side with respect to the focus plate in the direction along the optical axis of the photographing optical system. you place. As a configuration of this moving support mechanism, a first wall portion located on the subject side of the focus plate in the direction along the optical axis of the photographing optical system and substantially perpendicular to the plate surface of the focus plate is used as the focus plate support member. The mirror shock absorbing member is provided with a second wall portion substantially parallel to the first wall portion of the focus plate support member, and a mirror for the focus plate support member is provided on one of the first wall portion and the second wall portion. It is preferable to provide a long hole oriented in the longitudinal direction in the moving direction of the shock absorbing member, and to provide a protrusion that projects from the other of the first wall portion and the second wall portion and is slidably inserted into the long hole.

It is preferable to include an urging member that urges the mirror shock absorbing member in a direction opposite to the pressing direction by the movable mirror when the movable mirror moves from the first position to the second position.

The focus plate support member can be rotatably supported with respect to the fixing member. In this case, it has a support plate portion that is fixedly supported by the fixing member and an engagement / disengagement portion that is elastically deformable with respect to the support plate portion and can be engaged / disengaged with respect to the focus plate support member. Is provided with a lock member that determines the support position of the focus plate by the focus plate support member by engaging with the focus plate support member, one end of the lock member comes into contact with the support plate portion of the lock member, and the other end of the mirror shock absorbing member. It is possible to use at least one coil spring that comes into contact with the urging member. Further, it is preferable to provide a spring insertion hole for inserting the coil spring in the fixing member so that the support plate portion of the fixing member covers the spring insertion hole and is supported by the fixing member.

As a different form of the urging member, at least one leaf spring having a base supported by the mirror shock absorbing member and an elastically deformable elastic contact portion protruding from the base and contacting the fixing member may be used. ..

The fixing member may be provided with a notch for accommodating at least a part of the mirror shock absorbing member.

As a component of the observation optical system, a transparent display that is fixedly supported by a fixed member, transmits subject light when the movable mirror is in the first position, and displays information on the observed image. A device may be provided, and the position of the focus plate may be determined by contact with the transmission display while the focus plate is supported by the focus plate support member.

According to the present invention, a mirror shock absorbing member that absorbs shock when the movable mirror moves to the retracted position side approaching the finder optical system is arranged on the subject side from the center of the focus plate, and is used as a focus plate support member. On the other hand, by arranging a moving support mechanism that movably supports the mirror shock absorbing member on the subject side with respect to the focus plate, it is possible to efficiently absorb the shock of the movable mirror with a simple configuration and to perform shock absorption of the movable mirror. It is possible to prevent the structure of the structure from becoming complicated and large.

It is sectional drawing which shows the internal structure in the mirror down state of the single-lens reflex camera provided with the mirror shock absorption mechanism of 1st Embodiment to which this invention was applied. It is sectional drawing which shows the internal structure in the mirror-up state of a single-lens reflex camera. It is sectional drawing which shows the relationship between the quick return mirror and the finder optical system in the mirror lockup state of FIG. It is a cross-sectional view which expanded a part of FIG. It is sectional drawing which shows the state which the shock absorbing member is pressed by the quick return mirror when it becomes a mirror lockup state. It is sectional drawing which follows the VI-VI line of FIG. It is a perspective view of the mirror shock absorption mechanism and the finder optical system of 1st Embodiment. It is an enlarged perspective view of a part of FIG. 7. It is a perspective view which shows the state which the finder optical system and the mirror shock absorption mechanism of 1st Embodiment are assembled with respect to a fixed member. It is a perspective view of the mirror shock absorption mechanism and the finder optical system of the 2nd Embodiment. It is an enlarged perspective view of a part of FIG. It is sectional drawing which shows the state which the finder optical system and the mirror shock absorption mechanism of 2nd Embodiment are assembled with respect to a fixed member along the plane XII of FIG.

1 and 2 show the internal structure of a single-lens reflex camera 10 which is an embodiment of an imaging device to which the present invention is applied. The single-lens reflex camera 10 has a quick return mirror 11 (movable mirror) that can operate in the mirror down state (first position) shown in FIG. 1 and the mirror lockup state (second position) shown in FIGS. 2 to 4. doing. The quick return mirror 11 has a main mirror M1 and a sub mirror M2.

When the quick return mirror 11 is in the mirror down state of FIG. 1, the subject light beam passing through the photographing lens system 13 of the lens barrel 12 is reflected by the main mirror M1 and guided to the finder optical system 14 (observation optical system). Then, a part of the subject light beam passes through the main mirror M1 and is reflected by the sub mirror M2 and guided to the focus detection device 15. When the quick return mirror 11 is in the mirror lockup state of FIG. 2, the subject luminous flux passing through the photographing lens system 13 of the lens barrel 12 is not reflected by the main mirror M1 and the sub mirror M2, and the image sensor 16 (light receiving unit for photographing). Proceed towards. In addition, in FIGS. 1 and 2, the lens barrel 12 shows only a part near the rear end, and shows only the rearmost lens among the plurality of lenses (groups) constituting the photographing lens system 13. .. The focus detection device 15 is a well-known device that detects a focused state by a phase difference method, and is schematically shown in FIGS. 1 and 2.

The front-back direction in the following description of the single-lens reflex camera 10 means a direction along the optical axis OA (FIGS. 1 and 2) of the photographing lens system 13, and the subject side (FIGS. 1 and 2) in which the lens barrel 12 is located. The left side of the lens is the front, and the image sensor 16 side (the right side of FIGS. 1 and 2) is the rear. In FIGS. 1 and 2, the direction perpendicular to the optical axis OA is the vertical direction, the finder optical system 14 side is upward, and the focus detection device 15 side is downward. Further, the direction perpendicular to the paper surface of FIGS. 1 and 2 is defined as the left-right direction. Note that the vertical and horizontal directions here are for convenience, and the orientation changes depending on how the single-lens reflex camera 10 is held. Therefore, the vertical direction does not always match the vertical direction, and the horizontal direction does not always match the horizontal direction. Absent.

The finder optical system 14 has a focusing plate (focusing screen) 20, a transmissive liquid crystal 21 (transmissive display), a distortion correction lens 22, and a pentagonal roof prism 23 in this order from the bottom near the quick return mirror 11. It has an eyepiece (not shown) located behind the Ludha prism 23. Behind the pentagonal roof prism 23, a photometric sensor 24 is provided above the eyepiece.

A shutter unit 25 is provided between the quick return mirror 11 and the image sensor 16 in the front-rear direction. The shutter unit 25 has a focal plane shutter that controls the exposure time by operating the front curtain and the rear curtain with a predetermined time difference, and normally closes the shutter to allow the subject light beam to travel toward the image sensor 16. At the time of shielding and exposure, the front curtain and the rear curtain are operated to reach the image sensor 16 with the subject light beam.

The quick return mirror 11 supports the main mirror M1 on the main mirror sheet 30 and the sub mirror M2 on the sub mirror sheet 35. The main mirror sheet 30 has a main mirror M1 placed in the recess 31, and has a contact portion 32 on the front edge of the recess 31 that slightly protrudes from the main mirror M1. Further, an opening 33 penetrating the front and back surfaces of the main mirror sheet 30 is formed in the center of the recess 31. The portion of the main mirror M1 that overlaps with the opening 33 is a half mirror, and the light transmitted through the main mirror M1 can travel to the back surface side of the main mirror sheet 30 through the opening 33.

The main mirror sheet 30 is pivotally supported by a hinge pin 34 and is supported by a link mechanism (not shown). The main mirror sheet 30 and the main mirror M1 move to the finder light guide position shown in FIG. 1 and the retracted position shown in FIGS. 2 to 4 by rotating around the hinge pin 34 and changing the position by the link mechanism. be able to. As shown in FIGS. 1 to 3, the hinge pin 34 moves closer to the optical axis OA at the finder light guide position, and the hinge pin 34 moves upward away from the optical axis OA at the retracted position.

The sub mirror sheet 35 is pivotally supported on the main mirror sheet 30 via a support shaft (not shown). The sub mirror sheet 35 operates in conjunction with the main mirror sheet 30. When the main mirror sheet 30 is in the finder light guide position of FIG. 1, the sub mirror sheet 35 and the sub mirror M2 are held in a protruding position that projects obliquely rearward with respect to the main mirror sheet 30. When the main mirror sheet 30 is in the retracted position of FIGS. 2 to 4, the sub mirror sheet 35 and the sub mirror M2 are held in a storage position along the back surface of the main mirror sheet 30. At the storage position, a part of the sub mirror sheet 35 and the sub mirror M2 enters the opening 33 of the main mirror sheet 30.

In the mirror down state (FIG. 1) of the quick return mirror 11, the main mirror sheet 30 is in the finder light guide position and the sub mirror sheet 35 is in the protruding position. In the mirror-up state (FIGS. 2 to 4) of the quick return mirror 11, the main mirror sheet 30 is in the retracted position and the sub mirror sheet 35 is in the retracted position. The quick return mirror 11 can be driven by a mirror drive mechanism (not shown) including the link mechanism described above to bring the mirror down state and the mirror up state.

In the mirror down state of FIG. 1, the main mirror M1 is obliquely provided on the photographing optical path between the photographing lens system 13 and the shutter unit 25, and the subject luminous flux passing through the photographing lens system 13 is reflected upward by the main mirror M1. .. A focus plate 20 is provided above the main mirror M1 at a position optically equivalent to the light receiving surface of the image sensor 16, and the subject light beam reflected by the main mirror M1 is imaged on the focus plate 20 to form a transmissive liquid crystal. The subject image can be observed through the distortion correction lens 22, the pentagonal roof prism 23, and the eyepiece (that is, via the finder optical system 14). In this state, photometry can be performed by the photometric sensor 24 provided behind the pentagonal roof prism 23. Further, in the mirror down state, a predetermined proportion of the subject luminous flux transmitted through the main mirror M1 which is a half mirror travels backward through the opening 33, and the focus detection device 15 is provided by the sub mirror M2 located behind the opening 33. Reflected towards. The focus detection device 15 receives the subject light beam guided through the sub mirror M2 and detects the in-focus state by a phase difference method. The focusing information (focusing state, focusing area, etc.) of the subject obtained by the focus detecting device 15 is superimpose displayed on the transmissive liquid crystal 21, and the focusing information can be observed together with the subject image through the eyepiece.

In the mirror lockup state of FIGS. 2 to 4, the quick return mirror 11 approaches the focus plate 20, and the main mirror M1 and the sub mirror M2 are close to parallel to the focus plate 20, respectively. In this state, the main mirror sheet 30 (main mirror M1) and the sub mirror sheet 35 (sub mirror M2) block the subject light beam for exposure traveling from the photographing lens system 13 of the lens barrel 12 toward the shutter unit 25 and the image sensor 16. Instead, the shutter unit 25 can drive the focal plane shutter to reach the image sensor 16 with the subject light beam.

The quick return mirror 11 and the finder optical system 14 are supported via the fixing member 40 shown in FIG. The fixing member 40 has a box-shaped mirror box 41. Although not shown, the components of the mirror drive mechanism that operates the quick return mirror 11 in the mirror down state and the mirror lockup state described above are arranged along the side walls 42 (FIG. 9) on both sides of the mirror box 41. Further, a shutter charge mechanism for charging the shutter of the shutter unit 25 and an aperture drive mechanism for operating the aperture in the lens barrel 12 are also arranged along the side walls 42 on both sides of the mirror box 41.

An annular lens mount 36 (FIGS. 1 to 3) for attaching / detaching the lens barrel 12 is provided on the front surface side of the mirror box 41. The mirror box 41 is formed with openings in the front and rear and in the upper and lower directions. In both the mirror down state (FIG. 1) and the mirror up state (FIGS. 2 to 4), the subject light beam passing through the photographing lens system 13 of the lens barrel 12 attached to the lens mount 36 is mirrored from the front opening. Enter the box 41. The shutter unit 25 and the image sensor 16 are provided at a position facing the opening behind the mirror box 41, and the focus detection device 15 is provided at a position facing the opening below the mirror box 41. The components of the finder optical system 14 are supported in and near the opening above the mirror box 41. The support structure of the component of the finder optical system 14 will be described.

The fixing member 40 has a support frame 43 (FIG. 3) above the mirror box 41, and the transmissive liquid crystal 21 is supported by the support frame 43. The transmissive liquid crystal 21 is a plate-like body having a substantially rectangular outer shape, and is supported by the support frame 43 with a pair of short sides in the front-rear direction and a pair of long sides in the left-right direction. The support frame 43 has a vertical wall 44 that surrounds the opening above the mirror box 41, and a flange 45 that protrudes from the vertical wall 44 and narrows the opening above the mirror box 41. The vertical wall 44 and the flange 45 are They are provided at the front-rear position and the left-right position corresponding to the four sides of the transmissive liquid crystal 21, respectively. The position of the transmissive liquid crystal 21 in the front-rear direction and the left-right direction is determined by surrounding four sides by the vertical wall 44, and the position in the vertical direction is determined by the peripheral edge of the downward-facing surface abutting on the flange 45.

As shown in FIG. 9, the fixing member 40 has a focus plate 20, a transmissive liquid crystal 21, and a front plate 46 that covers the front of the distortion correction lens 22 in the finder optical system 14, and is near the center of the front plate 46 in the left-right direction. A notch 47 is formed by partially cutting out. The notch 47 is provided at a position in the vertical direction corresponding to the focus plate 20 and the transmissive liquid crystal 21, and a bridge entanglement portion 48 forming an upper edge portion of the front plate 46 is provided above the notch 47. As shown in FIG. 3, the support frame 43 does not exist at the formation position of the notch 47. Support frames 43 are provided on the front plate 46 at the left and right portions of the cutout portion 47, and the front edge portion of the transmissive liquid crystal 21 is also reliably supported by the support frame 43.

A prism support frame 50 made of a member different from the fixing member 40 is fixed to the upper part of the support frame 43 of the fixing member 40. As shown in FIG. 3, the prism support frame 50 is located above the lens holding portion 51 for fitting and holding the peripheral edge portion of the distortion correction lens 22 and the lower surface (incident surface) of the pentagonal roof prism 23. ) Has a prism support surface 52 that supports the peripheral edge portion. The distortion correction lens 22 and the pentagonal roof prism 23 are supported by a prism support frame 50, and a dustproof cushion 53 and a light shielding frame 54 are sandwiched between them. The dust-proof cushion 53 and the light-shielding frame 54 each have a frame shape along the peripheral edge of the distortion correction lens 22. The dustproof cushion 53 forms a dustproof space by being sandwiched between the distortion correction lens 22 and the pentagonal roof prism 23 in a compressed state. The light-shielding frame 54 blocks harmful ambient light from the distortion correction lens 22 toward the pentagonal roof prism 23.

As shown in FIG. 3, the dustproof cushion 55 is sandwiched between the lower surface of the prism support frame 50 and the transmissive liquid crystal 21. The dustproof cushion 55 has a rectangular frame shape along the peripheral edge of the transmissive liquid crystal 21, and is sandwiched in a compressed state to form a dustproof space between the transmissive liquid crystal 21 and the distortion correction lens 22. Further, a force of pressing the compressed dustproof cushion 55 against the transmissive liquid crystal 21 toward the flange 45 of the support frame 43 acts, and the transmissive liquid crystal 21 is stably supported. A viewing frame 56 is sandwiched between the transmissive liquid crystal 21 and the flange 45. The field frame 56 has a rectangular frame shape along the peripheral edge of the transmissive liquid crystal 21, and determines the observation range (field of view) in the finder optical system 14.

The focus plate 20 is a plate-like body having a substantially rectangular outer shape like the transmissive liquid crystal 21, and is a focus plate 20 via a focus plate support frame 60 (focus plate support member) as shown in FIGS. 3 and 7. Is supported. The focus plate support frame 60 has vertical walls 61 that surround the front, back, left, and right of the focus plate 20, and a bent portion 62 that faces the peripheral edge of the lower surface of the focus plate 20 is provided at the lower end of the vertical wall 61. The vertical wall 61 of the focus plate 20 regulates the movement of the focus plate 20 in the front-rear direction and the left-right direction with respect to the focus plate support frame 60. The focus plate 20 has a flange 57 (FIG. 3) that abuts on the upper end of the vertical wall 61, and the contact between the flange 57 and the vertical wall 61 causes the focus plate 20 to move downward with respect to the focus plate support frame 60. Is regulated. Further, a focus plate support spring 63 (FIG. 8) made of a leaf spring is inserted between the lower surface of the focus plate 20 and the bent portion 62. As shown in FIG. 7, a pair of support shafts 64 projecting in the left-right direction are provided near the rear ends of the left and right vertical walls 61 of the focus plate support frame 60. As shown in FIG. 9, each support shaft 64 is pivotally supported by a shaft support portion 49 formed on the fixing member 40, and the focus plate support frame 60 can rotate (swing) around the support shaft 64. ..

The lock member 65 that regulates the rotation of the focus plate support frame 60 is supported by the front plate 46 of the fixing member 40. The lock member 65 is made of a metal plate material, and has a support plate portion 66 supported on the upper surface of a bridge entanglement portion 48 which is a part of the front plate 46, and an engagement / disengagement protruding from the support plate portion 66 as a cantilever protrusion. It has a part 67. The engaging / disengaging portion 67 projects upward with respect to the support plate portion 66 and then is curved downward, and extends below the support plate portion 66. As shown in FIG. 8, the engaging / disengaging portion 67 has a through hole 67a penetrating in the front-rear direction, and an engaging piece 68 is provided on the lower edge of the through hole 67a. The support plate portion 66 is fixed to the bridge entanglement portion 48 of the front plate 46 by three fixing screws 69, and the engagement / disengagement portion 67 having a free end at the tip can be elastically deformed in the front-rear direction with the support plate portion 66 as a base. is there.

As shown in FIG. 8, a lock protrusion 70 is provided at substantially the center in the left-right direction of the front portion of the focus plate support frame 60. The lock member 65 can engage and disengage the engaging piece 68 with the lock protrusion 70 by elastically deforming the engaging and disengaging portion 67 in the front-rear direction. The engaging / disengaging portion 67 maintains a locked state in which the engaging piece 68 and the lock protrusion 70 are engaged when no external force is applied. In this locked state, since the downward movement of the lock protrusion 70 is restricted by the engaging piece 68, the focus plate support frame 60 does not rotate around the support shaft 64 and is held at a fixed holding position (FIGS. 1 to 1 to FIG. 5. It is held at the position shown in FIGS. 7 to 9). As shown in FIG. 3, when the focus plate support frame 60 is held at the holding position by the lock member 65, the focus plate washer 71 is sandwiched between the focus plate 20 and the transmissive liquid crystal 21, and the focus plate 20 is transparent. The vertical position is determined by the contact with the liquid crystal 21 (indirect contact relationship with the focus plate washer 71 sandwiched between them). The focus plate washer 71 has a rectangular frame shape along the peripheral edges of the focus plate 20 and the transmissive liquid crystal 21. The focus plate support spring 63 (FIG. 8) that abuts on the lower surface of the focus plate 20 elastically deforms while the focus plate support frame 60 is in the holding position to generate an urging force that presses the focus plate 20 against the focus plate washer 71. .. As shown in FIG. 3, the focus plate 20 supported by the focus plate support frame 60 at the holding position has a substantially parallel relationship with the transmissive liquid crystal 21, and is held at an imaging position optically equivalent to the image sensor 16. Will be done.

In this way, the distance between the focus plate 20 and the transmissive liquid crystal 21 can be reduced by forming the structure in which the vertical position of the focus plate 20 is determined by the transmissive liquid crystal 21 without using the fixing member 40. In the finder optical system 14, information display such as focusing information displayed on the transmissive liquid crystal 21 is observed through the eyepiece together with the subject image. Therefore, by reducing the distance between the focus plate 20 and the transmissive liquid crystal 21, the focus plate 20 The deviation of the diopter of the information display on the transmissive liquid crystal 21 with respect to the subject image formed above is reduced, and the observation quality of the finder optical system 14 can be improved.

As shown in FIG. 9, the engaging / disengaging portion 67 of the lock member 65 is exposed in the opening in front of the mirror box 41 through the notch 47 of the fixing member 40, and the lens barrel 12 is removed from the lens mount 36. The engagement / disengagement unit 67 can be operated in the state. Then, by pulling the engaging / disengaging portion 67 of the lock member 65 forward to elastically deform it, the engaging piece 68 is released from the position where it overlaps with the lock protrusion 70, and the locked state by the lock member 65 is released. By releasing the locked state, the focus plate support frame 60 can rotate about the support shaft 64. By rotating the focus plate support frame 60 to an open position (not shown) that lowers the front end downward, the focus plate 20 is separated from the transmissive liquid crystal 21 and its vertical positioning is released, and the focus plate 20 is removed (replaced). Also, maintenance around the focus plate 20 and the transmissive liquid crystal 21 can be performed.

The engaging / disengaging portion 67 of the lock member 65 is provided with a tapered portion 67b below the engaging piece 68. When the focus plate support frame 60 is rotated from the open position to the holding position, the lock protrusion 70 comes into contact with the tapered portion 67b. Then, due to the inclined shape of the tapered portion 67b, a component force for pressing the engaging / disengaging portion 67 forward is generated from the force in the rotation direction of the focus plate support frame 60, and the locking projection 70 is elastically deformed while the engaging / disengaging portion 67 is elastically deformed. get over. When the focus plate support frame 60 reaches the holding position, the lock protrusion 70 is released from being pushed into the tapered portion 67b, and the engaging piece 68 is locked to engage with the lock protrusion 70. That is, the return of the focus plate support frame 60 from the open position to the holding position can be easily performed only by rotating the focus plate support frame 60.

The single-lens reflex camera 10 includes a mirror shock absorbing mechanism that absorbs shock when the quick return mirror 11 is in a mirror lockup state and suppresses vibration (bound). The mirror shock absorbing mechanism includes a shock absorbing member 72 (mirror shock absorbing member) movably supported by the focus plate support frame 60. As shown in FIGS. 7 and 8, the shock absorbing member 72 is a member that is long in the left-right direction, and has a vertical plate portion 73 (moving support mechanism, a second wall portion) and a lower plate portion over substantially the entire longitudinal direction. 74 is provided. Further, the upper plate portion 75 is formed in a predetermined range from both ends in the longitudinal direction. The vertical plate portion 73 forms a wall portion extending in the vertical direction, the lower plate portion 74 projects rearward from the lower end of the vertical plate portion 73, and the upper plate portion 75 projects rearward from the upper end of the vertical plate portion 73. The vertical plate portion 73, the lower plate portion 74, and the upper plate portion 75 form a U-shaped cross-sectional structure that is open toward the rear.

As shown in FIGS. 7 and 8, the height of the vertical plate portion 73 of the shock absorbing member 72 is higher in the central portion than on both side portions in the longitudinal direction (left-right direction) in which the upper plate portion 75 is formed. A spring receiving seat 76 that protrudes forward from the upper end of the central portion of the vertical plate portion 73 is provided. Further, in the central portion of the vertical plate portion 73 having a large upward height, a pair of guide holes 77 (moving support mechanism, elongated holes) are formed at different positions in the left-right direction, and a pair of guide holes 77 (moving support mechanism, elongated holes) are formed. Access holes 78 are formed between the guide holes 77. Each guide hole 77 is an elongated hole that is long in the vertical direction. The access hole 78 is formed by cutting out the vertical plate portion 73 in a predetermined range in the left-right direction between the pair of guide holes 77, and performs an operation of releasing the locked state of the focus plate support frame 60 by the lock member 65 described above. At that time, the engagement / disengagement unit 67 can be operated through the access hole 78.

As shown in FIG. 4, the focus plate support frame 60 has a support wall 79 (moving support mechanism, first wall portion) that is separated forward from the focus plate 20. The support wall 79 forms a wall portion extending in the vertical direction (substantially perpendicular to the plate surface of the focus plate 20), and the front edge of the focus plate 20 of the vertical wall 61 holding the peripheral edge portion of the focus plate 20 is formed. It is located in front of the part to be held. A pair of guide pins 80 (moving support mechanism, protrusions) are attached to the support wall 79 at different positions in the left-right direction. Each guide pin 80 is inserted into an insertion hole formed in the support wall 79 and is prevented from coming off by a snap ring 81. Each guide pin 80 has a guide portion 80a that protrudes forward from the support wall 79 and is inserted into the guide hole 77, and a retaining portion 80b that is located in front of the guide portion 80a. Both the guide portion 80a and the retaining portion 80b are projecting portions having a circular cross section, and the diameter of the guide portion 80a is substantially the same as the width of the guide hole 77 in the left-right direction (short direction), and is above and below the guide hole 77. It is smaller than the length in the direction (longitudinal direction). The diameter of the retaining portion 80b is larger than the diameter of the guide portion 80a. With the guide pins 80 inserted into the guide holes 77, the vertical plate portion 73 of the shock absorbing member 72 is substantially parallel to the support wall 79 of the focus plate support frame 60, and the vertical plate portion 73 and the support wall 79 are mutually parallel. Face each other with a slight clearance so that there is no rattling between them.

Therefore, the shock absorbing member 72 with respect to the focus plate support frame 60 due to the contact relationship between the vertical plate portion 73 and the support wall 79 and the sliding relationship between each guide hole 77 and each guide pin 80 (particularly the guide portion 80a). Therefore, the focus plate 20 is movably supported in the plate thickness direction (direction substantially orthogonal to the plate surface of the focus plate 20). When the focus plate support frame 60 is in the holding position shown in each figure (when the focus plate 20 is held in the imaging position), the shock absorbing member 72 moves in the vertical direction with respect to the focus plate support frame 60. .. The movement of the shock absorbing member 72 with respect to the focus plate support frame 60 in the left-right direction is restricted by the contact between the side surface of each guide hole 77 and the guide portion 80a of each guide pin 80. Further, as shown in FIG. 4, the vertical plate portion 73 is sandwiched between the retaining portion 80b of each guide pin 80 and the support wall 79 of the focus plate support frame 60, so that the shock absorbing member for the focus plate support frame 60 The movement of 72 in the front-back direction is restricted.

The shock absorbing member 72 is made of a material having required rigidity (strength) and hardness so as to be smoothly and movably supported by the focus plate support frame 60 without causing inclination or distortion due to deformation. .. As an example, by using a metal plate material such as stainless steel, the shock absorbing member 72 can be made compact (thin) while ensuring strength, which contributes to the improvement of space saving around the shock absorbing member 72. However, the material of the shock absorbing member 72 is not limited to this, and can be arbitrarily selected, and it is also possible to use a molded product of synthetic resin.

A coil spring 82 is inserted between the support plate portion 66 of the lock member 65 and the spring receiving seat 76 of the shock absorbing member 72. Two coil springs 82 are arranged at different positions in the left-right direction. As shown in FIGS. 4 to 6, the bridging portion 48 of the fixing member 40 is formed with a spring insertion hole 83 penetrating in the vertical direction, and the support plate of the lock member 65 fixed on the bridging portion 48. The portion 66 closes the opening on the upper end side of the spring insertion hole 83. Each coil spring 82 is inserted into the spring insertion hole 83, the upper end of the coil spring 82 abuts on the support plate portion 66 of the lock member 65, and the lower end of the coil spring 82 protruding below the spring insertion hole 83 is the spring receiver of the shock absorbing member 72. It abuts on the seat 76. 3 and 6 show the length of the coil spring 82 in the free state, and when each coil spring 82 is inserted in a compressed state rather than in the free state (FIGS. 4 and 5), the shock absorbing member 72 The force that moves and urges downwards works. The shock absorbing member 72 that has been moved and urged downward has a downward moving end (in each drawing except FIG. 5) in which the guide portion 80a of the guide pin 80 abuts on the upper end of each guide hole 77 in a state where no external force is applied. It is held in the indicated position). The spring insertion hole 83 has a cylindrical inner peripheral surface, and the coil spring 82 is inserted with a slight clearance from the inner peripheral surface of the spring insertion hole 83, and the coil spring is inserted by the inner peripheral surface of the spring insertion hole 83. The buckling of 82 is prevented.

As shown in FIG. 6, four spring insertion holes 83 arranged in the left-right direction are formed in the bridge entanglement portion 48 of the fixing member 40, and the support plate portion 66 of the lock member 65 and the spring of the shock absorbing member 72. A maximum of four coil springs 82 can be inserted between the receiving seats 76. In the present embodiment, the coil springs 82 are arranged in the two spring insertion holes 83 located at both ends in the left-right direction, but the coil springs 82 are arranged according to the magnitude of the urging force applied to the shock absorbing member 72 and the balance of the urging forces. The number and arrangement of the can be arbitrarily selected.

An elastic shock absorber 84 (mirror shock absorbing member) is attached to the lower surface of the lower plate portion 75 of the shock absorbing member 72. As shown in FIGS. 7 and 8, the lower plate portion 75 has a length in the left-right direction substantially corresponding to the length in the left-right direction of the focus plate support frame 60, and an elastic shock absorber corresponding to this. 84 also has a long shape in the left-right direction. The elastic buffer 84 is made of a flexible material. Specifically, it is preferable to configure the elastic cushioning body 84 with a material having a high vibration damping property such as a foam material having an open cell structure or a closed cell structure or rubber.

As shown in FIG. 9, a part of the shock absorbing member 72 is located in the notch 47 of the fixing member 40. Specifically, the spring receiving seat 76 and the guide pin 80 projecting forward from the vertical plate portion 73 of the shock absorbing member 72 are housed inside the notch portion 47. As a result, it is possible to prevent the spring receiving seat 76 and the guide pin 80 from interfering with the front plate 46 of the fixing member 40. In particular, since the spring receiving seat 76 changes its position in the vertical direction as the shock absorbing member 72 moves, the width of the notch 47 in the left-right direction is set to be larger than the length of the spring receiving seat 76 in the left-right direction. The vertical width of the notch 47 is set to be larger than the vertical movement range of the spring receiving seat 76. Further, the notch 47 exposes the access hole 78 of the shock absorbing member 72 in the opening in front of the mirror box 41, and as described above, the unlocking operation of the engaging / disengaging portion 67 of the lock member 65 is performed through the notch 47. It can be carried out. The cutout portion 47 of the present embodiment has a structure in which the bridge entanglement portion 48 is provided only on the upper side and the lower portion is open, but the cutout portion can be configured as a penetrating portion in the front-rear direction without opening the lower portion. Is.

In the mirror down state shown in FIG. 1, the quick return mirror 11 is separated from the shock absorbing member 72, and the shock absorbing member 72 is held at the downward moving end by the urging force of the coil spring 82. When the quick return mirror 11 changes from the mirror down state to the mirror up state shown in FIGS. 2 to 4, the vicinity of the front end of the main mirror sheet 30 provided with the contact portion 32 (and the vicinity of the front end of the main mirror M1) is impacted. It comes into contact with the elastic buffer 84 of the absorbing member 72. At this time, as shown in FIG. 5, the shock absorbing member 72 is pushed upward from the downward moving end against the load of the coil spring 82 to absorb the shock, and the bounce of the quick return mirror 11 can be suppressed. At the time of this shock absorption, the urging force of the coil spring 82 is set so that the upward movement of the shock absorbing member 72 is stopped before the guide portion 80a of the guide pin 80 comes into contact with the upper end of the guide hole 77. Therefore, a strong impact does not act on the focus plate support frame 60 from the shock absorbing member 72, and the structure is such that the shock absorbing member 72 is movably supported by the focus plate support frame 60, but adversely affects the focus plate 20. Can be prevented. Although FIG. 5 shows a state in which the spring receiving seat 76 approaches the lower surface of the bridge entanglement portion 48, the urging force of the coil spring 82 impacts before the spring receiving seat 76 abuts on the lower surface of the bridge entanglement portion 48. The size is set to stop the upward movement of the absorbing member 72.

As described above, the shock absorbing member 72 is supported in the space in front of the focus plate 20 via the focus plate support frame 60, and can move in the vertical direction along the support wall 79 of the focus plate support frame 60. Further, the structure (moving support mechanism) that movably supports the shock absorbing member 72 via the focus plate support frame 60 is a simple and compact structure using the guide holes 77 and the guide pins 80, and is a space in front of the focus plate 20. Since it is housed in, the space required for the operation of the shock absorbing member 72 can be small. Therefore, even if the component of the finder optical system 14 is large or there is no space in the portion along the side wall 42 of the mirror box 41, the shock absorbing member 72 is spaced without receiving the contract of the fixing member 40. A mirror shock absorbing mechanism that can be arranged efficiently and has excellent shock absorption while saving space can be obtained.

As shown in FIGS. 1 and 2, the hinge pin 34 that pivotally supports the main mirror sheet 30 is located behind the center of the focus plate 20 in the direction (front-back direction) along the optical axis OA. On the other hand, the shock absorbing member 72 is located in front of the focus plate 20 in the direction along the optical axis OA (front-back direction), and is the contact portion at the tip (front end) of the main mirror sheet 30 farthest from the hinge pin 34. The shock absorbing member 72 (elastic buffer 84) is located on the moving locus of 32. When the main mirror sheet 30 operates, the amount of movement and the acceleration increase as it moves away from the hinge pin 34 toward the tip side (contact portion 32 side), so that the shock absorbing member 72 is arranged in front of the focus plate 20. The configuration in which the shock is absorbed by contacting the contact portion 32 is also excellent in terms of the efficiency of shock absorption.

The vicinity of the rear end portion of the lower plate portion 74 of the shock absorbing member 72 has a positional relationship of overlapping with the focus plate 20 in the direction (front-back direction) along the optical axis OA. That is, the present invention does not require that the entire shock absorbing member 72 is located in front of the focus plate 20, and the shock absorbing member 72 is located in front of the center of the focus plate 20 at least in the direction along the optical axis OA. It is established if the requirement of being positioned (and the shock absorbing member 72 does not block the light flux for observation passing through the focus plate 20) is satisfied. As can be seen from FIG. 3, the region in which the lower plate portion 74 of the shock absorbing member 72 overlaps the focus plate 20 is located in front of the front edge of the viewing frame 56, and the lower plate portion 74 is the finder. It does not block the observation range of the optical system 14.

Further, the coil spring 82 that urges the shock absorbing member 72 is housed inside the bridging portion 48 which is a part of the fixing member 40, and the shock absorbing member 72 is housed in the notch 47 located below the bridging portion 48. Since the spring receiving seat 76 is housed, the shock absorbing member 72 and its supporting structure are excellent in space efficiency also in relation to the fixing member 40. In addition, the buckling prevention effect of the coil spring 82 can be obtained by the spring insertion hole 83 in the bridge entanglement portion 48. Further, since the support plate portion 66 of the lock member 65 for holding the focus plate support frame 60 is used to support the upper end of the coil spring 82, the effect of reducing the number of parts and improving the assembling property can be obtained.

10 to 12 show the mirror shock absorbing mechanism of the second embodiment. This mirror shock absorbing mechanism includes a leaf spring 85 (a urging member) that urges the shock absorbing member 72 downward. The leaf springs 85 are provided one by one near the ends of the shock absorbing member 72 in the left-right direction. As shown in FIG. 11, each leaf spring 85 is made of a metal plate material, and has a fixed portion 86 fixed to the front surface of the vertical plate portion 73 of the shock absorbing member 72 with a rivet 89 and a fixed portion 86 protruding rearward from the fixed portion 86. It has a base portion 87 supported by the upper plate portion 75 of the shock absorbing member 72, and a cantilever elastic contact portion 88 extending obliquely upward from the base portion 87. The elastic contact portion 88 can be elastically deformed in the vertical direction with the base portion 87 as a fulcrum. The two leaf springs 85 project their elastic contact portions 88 from the left-right end portion of the shock absorbing member 72 toward the center in the direction in which the tips (free ends) of the shock absorbing member 72 approach each other.

As shown in FIG. 12, the support frame 43 of the fixing member 40 is located above the elastic contact portion 88 of each leaf spring 85. The amount of protrusion of the elastic contact portion 88 in the free state (shown by the solid line in FIG. 12) upward is larger than the vertical distance between the upper plate portion 75 of the shock absorbing member 72 and the lower surface of the support frame 43. The elastic contact portion 88 abuts on the lower surface of the support frame 43 in a state of being elastically deformed downward (indicated by a chain line in FIG. 12). Then, the elastic contact portion 88 is urged downward by the force that the elastic contact portion 88 tries to restore from the elastic deformation.

The first embodiment has an advantage that the urging force on the shock absorbing member 72 can be easily adjusted (changed) by setting the number and length of the coil springs 82. In the second embodiment, the shock absorbing member 72 receives the urging force from the leaf spring 85 at a position in the front-rear direction close to the plate surface of the vertical plate portion 73 that receives guidance from the focus plate support frame 60 and the guide pin 80. There is an advantage that a moment in the rotational direction (a force for tilting in the front-rear direction) is unlikely to act on the shock absorbing member 72.

Although the present invention has been described above based on the illustrated embodiment, the present invention is not limited to the illustrated embodiment. For example, as a configuration for supporting the shock absorbing member 72 so as to be movable in the vertical direction, the guide hole 77 is formed in the shock absorbing member 72 and the guide pin 80 is provided in the focus plate support frame 60 in the embodiment. The member forming the (guide hole 77) and the protrusion (guide pin 80) can be reversed. Further, since the vertical plate portion 73 of the shock absorbing member 72 and the support wall 79 of the focus plate support frame 60 each have a thin plate shape in the front-rear direction, a long hole (guide hole 77) and a protrusion (guide pin 80) are formed. However, when conditions such as the shape of the shock absorbing member are different, a guide shaft and a guide hole, a groove and a convex portion having a concave cross section, etc. are provided as a structure for movably supporting the shock absorbing member. It is possible to adopt various structures other than elongated holes and protrusions.

The mirror shock absorbing member of the embodiment has a structure in which an elastic cushioning body 84 is attached to a lower portion of a plate-shaped shock absorbing member 72 bent at a plurality of places, and the elastic cushioning body 84 enhances quietness at the time of mirror contact. However, the mirror shock absorbing member to which the present invention is applied is not limited to this. For example, it is also possible to adopt a mirror shock absorbing member in a form that does not have a portion corresponding to the elastic buffer 84.

Although the coil spring 82 and the leaf spring 85 are selectively used as the urging member for urging the mirror shock absorbing member in each embodiment, the coil spring 82 and the leaf spring 85 can also be used together. Further, any urging member can be used in addition to the coil spring 82 and the leaf spring 85 spring. For example, as the spring, a tension spring or the like can be used instead of the compression spring such as the coil spring 82. Further, as a configuration other than the spring, an urging member made of a material such as foam material or rubber may be used.

Although the quick return mirror 11 of the embodiment includes a main mirror M1 and a sub mirror M2, the present invention can be applied to a movable mirror of a type including only the main mirror M1.

The single-lens reflex camera 10 of the embodiment is a so-called digital camera that uses an image sensor 22 as a light receiving unit for photographing, but the present invention can also be applied to an imaging device that uses a silver salt film as a light receiving unit for photographing. ..

10 Single-lens reflex camera (imaging device)
11 Quick return mirror (movable mirror)
12 Lens barrel 13 Shooting lens system 14 Finder optical system (observation optical system)
15 Focus detector 16 Image sensor (light receiving part for photography)
20 Focus plate 21 Transmissive liquid crystal (transmissive display)
22 Distortion correction lens 23 Pentagonal Dach prism 24 Photometric sensor 25 Shutter unit 30 Main mirror sheet 31 Recess 32 Abutment 33 Opening 34 Hinge pin 35 Sub mirror sheet 36 Lens mount 40 Fixing member 41 Mirror box 42 Side wall 43 Support frame 44 Vertical wall 45 Flange 46 Front plate 47 Notch 48 Bridge entanglement 49 Shaft support 50 Prism support frame 51 Lens holding part 52 Prism support surface 53 Dust-proof cushion 54 Light-shielding frame 55 Dust-proof cushion 56 Viewing frame 60 Focus plate support frame (focus plate support member)
61 Vertical wall 62 Bending part 63 Focus plate support spring 64 Support shaft 65 Lock member 66 Support plate part 67 Engagement / disengagement part 67a Through hole 67b Taper part 68 Engagement piece 69 Fixing screw 70 Lock protrusion 71 Focus plate washer 72 Shock absorbing member ( Mirror shock absorber)
73 Vertical plate (moving support mechanism, second wall)
74 Lower plate part 75 Upper plate part 76 Spring receiving seat 77 Guide hole (moving support mechanism, long hole)
78 Access hole 79 Support wall (moving support mechanism, first wall part)
80 Guide pin (moving support mechanism, protrusion)
80a Guide part 80b Retaining part 81 Snap ring 82 Coil spring (urging member)
83 Spring insertion hole 84 Elastic shock absorber (mirror shock absorbing member)
85 leaf spring (urging member)
86 Fixed part 87 Base part 88 Elastic contact part 89 Rivet M1 Main mirror M2 Sub mirror OA Optical axis of shooting lens system

Claims (8)

It can be moved to a first position that is located on the optical path of the shooting optical system and reflects the subject light to the observation optical system, and a second position that allows the subject light to pass through the shooting light receiving unit without being reflected. Movable mirror and
The focus plate that constitutes the observation optical system and
The focus plate support member that supports the focus plate and
When the movable mirror moves from the first position to the second position, the movable mirror comes into contact with the mirror shock absorbing member to absorb the shock .
With
The mirror shock absorbing member is located on the subject side from the center of the focus plate in the direction along the optical axis of the photographing optical system, and is supported by the focus plate support member so as to be movable in the thickness direction of the focus plate. It is,
A moving support mechanism that movably supports the mirror shock absorbing member with respect to the focus plate support member in the plate thickness direction of the focus plate is provided with respect to the focus plate in a direction along the optical axis of the photographing optical system. An imaging device characterized by being located on the subject side . The movement support mechanism
A first wall portion provided on the focus plate support member, located on the subject side of the focus plate in the direction along the optical axis of the photographing optical system and substantially perpendicular to the plate surface of the focus plate,
A second wall portion substantially parallel to the first wall portion of the focus plate support member provided on the mirror shock absorbing member, and
An elongated hole provided on one of the first wall portion and the second wall portion and oriented in the longitudinal direction in the moving direction of the mirror shock absorbing member with respect to the focus plate support member.
Imaging device according to claim 1, further comprising a projection and which is slidably inserted into the slots and protrudes from the other of said first wall portion and the second wall portion. Claim 1 or 2 having the mirror shock absorbing member having an urging member that urges the movable mirror in a direction opposite to the pressing direction by the movable mirror when the movable mirror moves from the first position to the second position. The imaging apparatus described. The focus plate support member is rotatably supported with respect to the fixing member.
It has a support plate portion that is fixedly supported by the fixing member, and an engagement / disengagement portion that is elastically deformable with respect to the support plate portion and can be engaged / disengaged with respect to the focus plate support member. Is provided with a lock member that engages the focus plate support member to determine the support position of the focus plate by the focus plate support member.
The imaging device according to claim 3 , wherein the urging member is at least one coil spring in which one end abuts on the support plate portion of the lock member and the other end abuts on the mirror shock absorbing member. The imaging device according to claim 4 , wherein the fixing member has a spring insertion hole for inserting the coil spring, and the support plate portion of the fixing member covers the spring insertion hole and is supported by the fixing member. The focus plate support member is rotatably supported with respect to the fixing member.
3. The urging member is at least one leaf spring having a base portion supported by the mirror shock absorbing member and an elastically deformable elastic contact portion protruding from the base portion and abutting against the fixing member. The imaging apparatus described. The imaging device according to any one of claims 4 to 6 , wherein the fixing member has a notch for accommodating at least a part of the mirror shock absorbing member. The observation optical system is fixedly supported by the fixing member, transmits the subject light when the movable mirror is in the first position, and displays information on the observed image. Equipped with a transparent display
The imaging apparatus according to any one of claims 4 to 7 , wherein the position of the focus plate is determined by contact with the transmission display while the focus plate is supported by the focus plate support member.

Images