JP2017194526A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of absorbing shock when a movable mirror travels to a side of an evacuation position approaching a fiber optical system with a simple configuration having improved space efficiency.SOLUTION: An imaging apparatus includes: a movable mirror capable of traveling to a first position that is positioned on an optical path of a photographing optical system and reflects object light to an observation optical system, and a second position for allowing the object light to pass through a photographing light reception part without reflection; a focus plate support member for supporting a focus plate; and a mirror shock absorption member for absorbing shock by allowing for contact by the movable mirror when the movable mirror travels from the first position to the second position. The mirror shock absorption member is positioned at a side of an object body from the center of the focus plate in a direction along a light axis of the photographing optical system, and is supported by the focus plate support member so as to be movable in a plate thickness direction of the focus plate.SELECTED DRAWING: Figure 7

Description

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

  In a single-lens reflex camera, which is an imaging device that has 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 photographic optical system to direct the subject light to the finder optical system side The movable mirror is retracted from the optical path of the photographing optical system when photographing (exposure). 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 retracting position of the movable mirror.

  Inside the single-lens reflex camera, there is a movement restricting section that abuts when the movable mirror reaches the viewfinder light guide position or retracted position and restricts further movement. When coming into contact with the restricting portion, there is a risk that vibration will occur due to an impact. The vibration of the movable mirror at the finder light guide position causes a shake of the subject image when observing with the finder optical system. In a single-lens reflex camera of a type that guides subject light to a focal length detection device or a sensor for photometry using a movable mirror in a state at the finder light guide position, while the movable mirror vibrates at the finder light guide position. Accurate focus state determination and photometry cannot be performed. The vibration of the movable mirror at the retracted position causes camera shake during exposure and a delay in exposure operation. In order to alleviate these problems, various shock absorbing mechanisms for suppressing the vibration of the movable mirror have been proposed. For example, Patent Literature 1 and Patent Literature 2 describe an impact absorbing mechanism that suppresses vibration of the movable mirror at the retracted position.

Japanese Patent No. 5849458 JP 2014-145878 A

  In the single-lens reflex camera described in Patent Document 1, an impact 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 driving mechanism for driving the movable mirror, a shutter charging mechanism, and the like, and the components of the finder optical system are also supported on the upper part of the mirror box. . In recent years, an image sensor (imaging device) used in a single-lens reflex camera has been increased in size, and accordingly, a finder optical system tends to be increased in size. Then, the subject that it becomes difficult to ensure the arrangement space of the impact absorbing mechanism for the retracted position that suppresses the vibration of the movable mirror at a position close to the finder optical system becomes difficult.

  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 with respect to a screen base that is a fixing member, and rotates coaxially with the screen holding member. A mirror up cushioning material holder is provided. A buffer material unit is fixed to the screen base, and the mirror-up buffer material is held by the mirror-up buffer material holder. When the movable mirror pivots to the retracted position, the movable mirror contacts the mirror-up cushioning material held by the mirror-up cushioning material holder, the mirror-up cushioning material holder slightly pivots and contacts the cushioning material unit, Absorbs impact from movable mirrors. In the shock absorbing mechanism of Patent Document 2, the shock absorbing unit that finally absorbs the shock is arranged using the space in front of the focusing screen. The shock absorbing mechanism extends from the movable mirror to the shock absorbing unit. As a structure, a mirror-up cushioning material holder, which is a rotating member that is long in the optical axis direction of the imaging optical system, is used, and there is a problem that the overall size becomes large. The screen base is fixed to the upper part of the mirror box, and a mirror-up cushioning material holder is rotatably supported on the screen base. For this reason, the mirror-up cushioning material holder has substantially the same configuration as that supported by the mirror box, and the same problem as that of Patent Document 1 described above occurs with respect to the support of the mirror-up cushioning material holder.

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

  The present invention includes 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 unit without being reflected. A movable mirror, a focus plate constituting the observation optical system, a focus plate support member for supporting the focus plate, and the movable mirror when the movable mirror moves from the first position to the second position. The mirror impact absorbing member is positioned closer to the subject than the center of the focusing plate in the direction along the optical axis of the imaging optical system. It is supported by a focus plate support member so as to be movable in the plate thickness direction of the plate.

  A moving support mechanism that supports the mirror shock absorbing member so as to be movable in the thickness direction of the focus plate with respect to the focus plate support member is disposed on the subject side with respect to the focus plate in a direction along the optical axis of the imaging optical system. It is preferable. As the structure of this moving support machine mechanism, a first wall portion that is located on the subject side of the focus plate in the direction along the optical axis of the photographing optical system and is substantially perpendicular to the plate surface of the focus plate is used as the focus plate support member. A mirror shock absorbing member having 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 on one of the first wall portion and the second wall portion. It is preferable to provide a long hole whose longitudinal direction is directed in the moving direction of the shock absorbing member, and to provide a protrusion that protrudes 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 provide a biasing member that biases the mirror impact 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 fixed member. In this case, it has a support plate portion 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, one end abuts on 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 in contact as the biasing member. Further, it is preferable that a spring insertion hole for inserting the coil spring is provided 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 part supported by the mirror shock absorbing member and an elastically deformable elastic contact part protruding from the base part 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 impact absorbing member.

  As a component of the observation optical system, a transmissive display that is fixedly supported by a fixed member and transmits subject light when the movable mirror is at the first position and displays information on an observed image. And a position of the focus plate may be determined by contact with the transmissive display in a state where 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 in a space-efficient manner with a simple configuration on the subject side from the center of the focus plate. Thus, the structure and size of the imaging device can be prevented from becoming complicated.

It is sectional drawing which shows the internal structure in the mirror down state of the single-lens reflex camera provided with the mirror impact absorption mechanism of 1st Embodiment to which this invention is 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 finder optical system in the mirror up state of FIG. It is sectional drawing to which a part of FIG. 3 was expanded. It is sectional drawing which shows the state by which the impact-absorbing member is pressed by the quick return mirror when it will be in a mirror up state. It is sectional drawing which follows the VI-VI line of FIG. It is a perspective view of the mirror impact absorption mechanism and finder optical system of a 1st embodiment. It is the perspective view which expanded a part of FIG. It is a perspective view which shows the state by which the finder optical system and the mirror impact absorption mechanism of 1st Embodiment are assembled | attached with respect to the fixing member. It is a perspective view of the mirror impact absorption mechanism and finder optical system of 2nd Embodiment. It is the perspective view which expanded a part of FIG. It is sectional drawing which shows the state by which the finder optical system and the mirror impact absorption mechanism of 2nd Embodiment are assembled | attached with respect to the fixing member along the plane XII of FIG.

  1 and 2 show the internal structure of a single-lens reflex camera 10 that is an embodiment of an imaging apparatus to which the present invention is applied. The single-lens reflex camera 10 has a quick return mirror 11 (movable mirror) operable in a mirror-down state (first position) shown in FIG. 1 and a mirror-up state (second position) shown in FIGS. 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 flux that has passed 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). A part of the subject light flux is transmitted through the main mirror M1, reflected by the sub-mirror M2, and guided to the focus detection device 15. When the quick return mirror 11 is in the mirror-up state of FIG. 2, the subject light flux that has passed through the photographing lens system 13 of the lens barrel 12 is not reflected by the main mirror M1 and the sub-mirror M2, but the image sensor 16 (photographing light receiving unit). Proceed toward. 1 and 2, the lens barrel 12 shows only a part near the rear end, and shows only the rearmost lens among a plurality of lenses (groups) constituting the photographing lens system 13. . The focus detection device 15 is a well-known device that detects an in-focus state by a phase difference method, and is schematically shown in FIGS. 1 and 2.

  In the following description of the single-lens reflex camera 10, the front-rear direction 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) where the lens barrel 12 is located. The left side of FIG. 1 is the front, and the image sensor 16 side (the right side of FIGS. 1 and 2) is the rear. 1 and 2, the direction perpendicular to the optical axis OA is the up-down direction, the finder optical system 14 side is the upper side, and the focus detection device 15 side is the lower side. Also, the direction perpendicular to the paper surface of FIGS. 1 and 2 is the left-right direction. Here, the vertical direction and the horizontal direction are for convenience, and the direction changes depending on how the single-lens reflex camera 10 is held, so the vertical direction matches the vertical direction and the horizontal direction does not always match the horizontal direction. Absent.

  The viewfinder optical system 14 includes, in order from the bottom near the quick return mirror 11, a focus plate (focusing screen) 20, a transmissive liquid crystal 21 (transmissive display), a distortion correction lens 22, and a pentagonal roof prism 23, and further pentagona. It has an eyepiece lens (not shown) located behind the Rudach prism 23. A photometric sensor 24 is provided behind the pentagonal roof prism 23 at a position 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. Normally, the shutter unit 25 is closed, and the subject luminous flux travels toward the image sensor 16 side. The front and rear curtains are operated during exposure and the subject luminous flux reaches the image sensor 16 during exposure.

  The quick return mirror 11 supports the main mirror M 1 on the main mirror sheet 30 and supports the sub mirror M 2 on the sub mirror sheet 35. The main mirror sheet 30 has the main mirror M1 placed in the recess 31, and has a contact portion 32 that protrudes slightly from the main mirror M1 at the front edge of the recess 31. In addition, an opening 33 that penetrates the front and back of the main mirror sheet 30 is formed in the center of the recess 31. The main mirror M1 is a half mirror at least at a portion overlapping the opening 33, and the light transmitted through the main mirror M1 can travel to the back side of the main mirror sheet 30 through the opening 33.

  The main mirror sheet 30 is supported by a hinge pin 34 and supported via 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 the rotation around the hinge pin 34 and the position change by the link mechanism. be able to. As shown in FIGS. 1 to 3, the hinge pin 34 approaches the optical axis OA at the finder light guide position, and the hinge pin 34 moves away from the optical axis OA at the retracted position.

  The sub mirror sheet 35 is pivotally supported with respect to 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 at the finder light guide position in FIG. 1, the sub mirror sheet 35 and the sub mirror M <b> 2 are held at protruding positions that protrude 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 M <b> 2 are held at the retracted position along the back surface of the main mirror sheet 30. At the retracted position, a part of the sub mirror sheet 35 and the sub mirror M2 enters the opening 33 of the main mirror sheet 30.

  When the quick return mirror 11 is in the mirror-down state (FIG. 1), the main mirror sheet 30 is in the finder light guide position, and the sub mirror sheet 35 is in the protruding position. When the quick return mirror 11 is in the mirror up state (FIGS. 2 to 4), 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 be in a mirror-down state and a 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 light flux that has passed 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 a subject light beam reflected by the main mirror M1 forms an image on the focus plate 20 to transmit transmissive liquid crystal. The object image can be observed through the distortion correction lens 22, the pentagonal roof prism 23, and the eyepiece lens (that is, via the viewfinder optical system 14). In this state, photometry by the photometric sensor 24 provided behind the pentagonal roof prism 23 is possible. In the mirror-down state, a predetermined proportion of the subject luminous flux that has passed through the main mirror M1 that is a half mirror travels rearward through the opening 33, and the focus detection device 15 is moved by the submirror M2 that is located behind the opening 33. Reflected towards. The focus detection device 15 receives the subject light beam guided via the sub-mirror M2 and detects the in-focus state by the phase difference method. Focus information of the subject (focus state, focus area, etc.) obtained by the focus detection device 15 is displayed superimposed on the transmissive liquid crystal 21, and the focus information can be observed together with the subject image through the eyepiece.

  2 to 4, the quick return mirror 11 approaches the focus plate 20, and the main mirror M <b> 1 and the sub mirror M <b> 2 are almost 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 flux for exposure that travels from the photographing lens system 13 of the lens barrel 12 toward the shutter unit 25 and the image sensor 16. First, the focal plane shutter can be driven by the shutter unit 25 so that the subject luminous flux can reach the image sensor 16.

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

  On the front side of the mirror box 41, an annular lens mount 36 (FIGS. 1 to 3) for attaching and detaching the lens barrel 12 is provided. The mirror box 41 has openings in the front and rear and the top and bottom. In both the mirror-down state (FIG. 1) and the mirror-up state (FIGS. 2 to 4), the subject luminous flux 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 box 41. The shutter unit 25 and the image sensor 16 are provided at a position facing the rear opening of the mirror box 41, and the focus detection device 15 is provided at a position facing the lower opening of the mirror box 41. The components of the finder optical system 14 are supported by the opening above the mirror box 41 and in the vicinity thereof. A support structure for the components 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 supports the transmissive liquid crystal 21 by the support frame 43. The transmissive liquid crystal 21 is a plate 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 includes 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 The front and rear positions and the left and right positions respectively corresponding to the four sides of the transmissive liquid crystal 21 are provided. The position of the transmissive liquid crystal 21 in the front-rear direction and the left-right direction is determined by the four sides being surrounded by the vertical wall 44, and the position in the vertical direction is determined by the peripheral edge of the surface facing downward contacting the flange 45.

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

  A prism support frame 50, which is a member different from the fixed member 40, is fixed to the upper part of the support frame 43 of the fixed member 40. As shown in FIG. 3, the prism support frame 50 includes a lens holding portion 51 that fits and holds the peripheral edge portion of the distortion correction lens 22, and a lower surface (incident surface) of the pentagonal roof prism 23 that is positioned above the lens holding portion 51. ) Of the prism support surface 52 for supporting the peripheral portion. The distortion correction lens 22 and the pentagonal roof prism 23 are supported by the prism support frame 50 and sandwich a dustproof cushion 53 and a light shielding frame 54 between each other. Each of the dustproof cushion 53 and the light shielding frame 54 has a frame shape along the periphery 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, a 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 periphery of the transmissive liquid crystal 21, and forms a dustproof space between the transmissive liquid crystal 21 and the distortion correction lens 22 by being sandwiched in a compressed state. Moreover, the force which presses toward the flange 45 of the support frame 43 with respect to the transmissive liquid crystal 21 from the compressed dustproof cushion 55 acts, and the transmissive liquid crystal 21 is supported stably. A field 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 periphery of the transmissive liquid crystal 21, and determines an observation range (field) in the finder optical system 14.

  The focus plate 20 is a plate-like body having a substantially rectangular outer shape similar to the transmissive liquid crystal 21, and the focus plate 20 is interposed via a focus plate support frame 60 (focus plate support member) as shown in FIGS. Is supported. The focus plate support frame 60 has a vertical wall 61 that surrounds the front and rear and the left and right sides of the focus plate 20, and a bent portion 62 that faces the periphery of the lower surface of the focus plate 20 is provided at the lower end of the vertical wall 61. The vertical movement of the focus plate 20 with respect to the focus plate support frame 60 is restricted by the vertical wall 61. The focus plate 20 has a flange 57 (FIG. 3) that abuts the upper end of the vertical wall 61, and the focus plate 20 moves downward with respect to the focus plate support frame 60 by the contact of the flange 57 and the vertical wall 61. Is regulated. Further, a focus plate support spring 63 (FIG. 8) made of a plate 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. .

  A lock member 65 that restricts 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 a support plate portion 66 supported on the upper surface of the bridging portion 48 that is a part of the front plate 46, and an engagement / disengagement protruding from the support plate portion 66 as a cantilevered protrusion. Part 67. The engagement / disengagement portion 67 protrudes upward with respect to the support plate portion 66 and then curves downward, and extends below the support plate portion 66. As shown in FIG. 8, the engaging / disengaging part 67 has a through hole 67a penetrating in the front-rear direction, and an engagement piece 68 is provided at the lower edge of the through hole 67a. The support plate portion 66 is fixed to the bridging portion 48 of the front plate 46 by three fixing screws 69, and an engaging / disengaging 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 the approximate center in the left-right direction of the front portion of the focus plate support frame 60. The lock member 65 is capable of engaging / disengaging the engagement piece 68 with the lock protrusion 70 by elastically deforming the engagement / disengagement portion 67 in the front-rear direction. The engagement / disengagement portion 67 maintains a locked state in which the engagement piece 68 and the lock protrusion 70 are engaged when no external force is applied. In this locked state, the downward movement of the lock projection 70 is restricted by the engagement piece 68, so that the focus plate support frame 60 does not rotate about the support shaft 64 and is held at a fixed holding position (FIGS. 1 to 5). 5, the position shown in FIGS. As shown in FIG. 3, when the focus plate support frame 60 is held at the holding position by the lock member 65, a focus plate washer 71 is sandwiched between the focus plate 20 and the transmissive liquid crystal 21, and the focus plate 20 is transmissive. The position in the vertical direction is determined by contact with the liquid crystal 21 (indirect contact relationship with the focus plate washer 71 interposed). The focus plate washer 71 has a rectangular frame shape along the periphery of the focus plate 20 and the transmissive liquid crystal 21. The focus plate support spring 63 (FIG. 8) that contacts the lower surface of the focus plate 20 is elastically deformed with the focus plate support frame 60 in the holding position, and generates a biasing 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 in the holding position has a substantially parallel relationship with the transmissive liquid crystal 21 and is held at an image formation position that is optically equivalent to the image sensor 16. Is done.

  In this way, by adopting a 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, the distance between the focus plate 20 and the transmissive liquid crystal 21 can be reduced. In the finder optical system 14, since information display such as focusing information displayed on the transmissive liquid crystal 21 is observed through the eyepiece together with the subject image, the focus plate 20 is reduced by reducing the distance between the focus plate 20 and the transmissive liquid crystal 21. The deviation of the diopter of the information display on the transmissive liquid crystal 21 with respect to the subject image formed on the top 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 engagement / disengagement portion 67 of the lock member 65 forward and elastically deforming, the engagement piece 68 is detached from the position where it overlaps the lock projection 70, and the locked state by the lock member 65 is released. By releasing the locked state, the focus plate support frame 60 can be rotated around 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 the vertical positioning is released, and the focus plate 20 is removed (replaced). In addition, 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 67 b below the engaging piece 68. When the focus plate support frame 60 is rotated from the open position toward the holding position, the lock protrusion 70 contacts the tapered portion 67b. Then, due to the inclined shape of the taper portion 67b, a component force that pushes the engagement / disengagement portion 67 forward is generated from the force in the rotational direction of the focus plate support frame 60. get over. When the focus plate support frame 60 reaches the holding position, the lock projection 70 is released from being pushed into the tapered portion 67b, and the engagement piece 68 is engaged with the lock projection 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 enters the mirror-up state and suppresses vibration (bound). The mirror shock absorbing mechanism includes a shock absorbing member 72 (mirror shock absorbing member) supported movably with respect to 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 a vertical plate portion 73 (moving support mechanism, second wall portion) and a lower plate portion over substantially the entire longitudinal direction. 74 is provided. Moreover, the upper board part 75 is formed in the predetermined range from the both ends of the longitudinal direction. The vertical plate portion 73 forms a wall portion extending in the vertical direction, the lower plate portion 74 protrudes rearward from the lower end of the vertical plate portion 73, and the upper plate portion 75 protrudes 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 opened rearward.

  As shown in FIGS. 7 and 8, the vertical plate portion 73 of the shock absorbing member 72 is higher in the central portion than the both side portions in the longitudinal direction (left-right direction) where 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. In addition, a pair of guide holes 77 (moving support mechanisms, long holes) are formed in the central portion of the vertical plate portion 73 where the height upward is increased, and the positions are changed in the left-right direction. An access hole 78 is formed between the guide holes 77. Each guide hole 77 is a long 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 the unlocking operation of the focus plate support frame 60 by the lock member 65 described above. At this time, the engaging / disengaging part 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 spaced forward from the focus plate 20. The support wall 79 forms a wall portion that extends 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 that holds the peripheral portion of the focus plate 20. It is located in front of the holding part. A pair of guide pins 80 (moving support mechanisms, 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 positioned in front of the guide portion 80a. Each of the guide portion 80a and the retaining portion 80b is a projecting portion 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). 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 each guide pin 80 inserted into each guide hole 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 connected. Opposite with a slight clearance between them.

  Therefore, the shock absorbing member 72 is in contact with the focus plate support frame 60 by 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 (especially the guide portion 80a). Thus, the focus plate 20 is supported so as to be movable 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 at the holding position shown in each drawing (when the focus plate 20 is held at the imaging position), the moving direction of the shock absorbing member 72 relative to the focus plate support frame 60 is the vertical direction. . The movement of the shock absorbing member 72 in the left-right direction with respect to the focus plate support frame 60 is limited by the contact between the side surface of each guide hole 77 and the guide portion 80 a of each guide pin 80. Further, as shown in FIG. 4, an impact absorbing member for the focus plate support frame 60 is obtained by sandwiching the vertical plate portion 73 between the retaining portion 80 b of each guide pin 80 and the support wall 79 of the focus plate support frame 60. The movement of 72 in the front-rear direction is restricted.

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

  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, a spring insertion hole 83 penetrating in the vertical direction is formed in the bridging portion 48 of the fixing member 40, and a support plate for 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 contacts the seat 76. 3 and 6 show the lengths of the coil springs 82 in a free state. When each coil spring 82 is inserted in a compressed state (FIGS. 4 and 5), the shock absorbing member 72 is shown. The force that moves and urges downwards works. The shock absorbing member 72 that is urged to move downward is a downward moving end (in each drawing excluding FIG. 5) in which the guide portion 80 a of the guide pin 80 abuts on the upper end of each guide hole 77 when no external force is applied. (Position shown). 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 formed by the inner peripheral surface of the spring insertion hole 83. 82 buckling is prevented.

  As shown in FIG. 6, four spring insertion holes 83 aligned in the left-right direction are formed in the bridging portion 48 of the fixing member 40, and the springs of the support plate portion 66 of the lock member 65 and the shock absorbing member 72 are formed. 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. However, the coil springs 82 are adapted 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 images can be arbitrarily selected.

  An elastic buffer 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 that substantially corresponds to the length in the left-right direction of the focus plate support frame 60, and an elastic buffer corresponding to this length. 84 also has a shape that is long in the left-right direction. The elastic buffer 84 is made of a flexible material. Specifically, the elastic buffer 84 may be made of a material having a high vibration damping property such as foam material or rubber having an open cell structure or closed cell structure.

  As shown in FIG. 9, a part of the impact absorbing member 72 is located in the notch 47 of the fixing member 40. Specifically, a spring receiving seat 76 and a guide pin 80 protruding forward from the vertical plate portion 73 of the shock absorbing member 72 are accommodated inside the notch portion 47. Thereby, interference of the spring seat 76 and the guide pin 80 with respect to the front plate 46 of the fixing member 40 can be prevented. In particular, since the spring receiving seat 76 changes its position in the vertical direction as the shock absorbing member 72 moves, the horizontal width of the notch 47 is set larger than the horizontal length of the spring receiving seat 76, and The vertical width of the notch 47 is set larger than the vertical movement range of the spring 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 the unlocking operation of the engagement / disengagement part 67 of the lock member 65 through the notch 47 as described above. It can be carried out. The cutout portion 47 of the present embodiment has a structure in which the bridging portion 48 is provided only in the upper part and the lower part is opened. However, the cutout part can be configured as a through part in the front-rear direction that does not open the lower part. It 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 movement end by the biasing 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) impacts. It contacts 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 lower 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 absorbing the impact, the urging force of the coil spring 82 is set so that the upward movement of the impact absorbing member 72 stops before the guide portion 80a of the guide pin 80 contacts the upper end of the guide hole 77. Accordingly, a strong impact does not act on the focus plate support frame 60 from the shock absorption member 72, and the impact absorption member 72 is movably supported by the focus plate support frame 60, but there is an adverse effect on the focus plate 20. Can be prevented. 5 shows a state in which the spring receiving seat 76 is close to the lower surface of the bridging portion 48, the urging force of the coil spring 82 is impacted before the spring receiving seat 76 comes into contact with the lower surface of the bridging 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 front space of the focus plate 20 via the focus plate support frame 60 and is movable in the vertical direction along the support wall 79 of the focus plate support frame 60. Further, the structure (moving support mechanism) for movably supporting 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 the front space of the focus plate 20. The space required for the operation of the shock absorbing member 72 can be small. Therefore, even when the component of the finder optical system 14 is large or when there is no space in the portion along the side wall 42 of the mirror box 41, the impact absorbing member 72 is not subjected to the contraction of the fixing member 40 and the space is provided. A mirror shock absorbing mechanism that can be arranged efficiently and is excellent in shock absorption while saving space is 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 portion of the focusing plate 20 in the direction along the optical axis OA (front-rear direction). On the other hand, the shock absorbing member 72 is located in front of the focusing plate 20 in the direction along the optical axis OA (front-rear direction), and is the abutting portion at the tip (front end) farthest from the hinge pin 34 in the main mirror sheet 30. The shock absorbing member 72 (elastic shock absorber 84) is positioned on the movement locus of 32. When the main mirror sheet 30 operates, the amount of movement and acceleration increase as it moves away from the hinge pin 34 and advances toward the distal end side (abutting portion 32 side). Therefore, an impact absorbing member 72 is disposed in front of the focus plate 20. The configuration in which the impact is absorbed by contact with the contact portion 32 is also excellent in terms of the efficiency of impact absorption.

  Note that the vicinity of the rear end portion of the lower plate portion 74 in the shock absorbing member 72 is in a positional relationship overlapping the focus plate 20 in the direction along the optical axis OA (front-rear direction). That is, the present invention does not require the entire shock absorbing member 72 to be positioned in front of the focus plate 20, and the shock absorbing member 72 is at least ahead of the center of the focus plate 20 in the direction along the optical axis OA. It is established if it satisfies the requirement of being located (and not blocking the observation light beam passing through the focusing plate 20 by the shock absorbing member 72). As can be seen from FIG. 3, the region where the lower plate portion 74 of the shock absorbing member 72 overlaps with the focus plate 20 is located in front of the front edge of the field frame 56, and the lower plate portion 74 is located in the viewfinder. The observation range by the optical system 14 is not obstructed.

  In addition, the coil spring 82 that biases the shock absorbing member 72 is housed in the bridging portion 48 that is a part of the fixing member 40, and the shock absorbing member 72 is placed in the notch 47 positioned below the bridging portion 48. Since the spring receiving seat 76 is accommodated, the shock absorbing member 72 and its support structure are excellent in space efficiency even in the relationship with the fixing member 40. In addition, the effect of preventing buckling of the coil spring 82 by the spring insertion hole 83 in the bridging portion 48 can also be obtained. 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 improving the assemblability by reducing the number of parts can be obtained.

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

  As shown in FIG. 12, the support frame 43 of the fixing member 40 is positioned above the elastic contact portion 88 of each leaf spring 85. Since the amount of upward protrusion of the elastic contact portion 88 (shown by a solid line in FIG. 12) in the free state 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 contacts the lower surface of the support frame 43 in a state of being elastically deformed downward (shown by a one-dot chain line in FIG. 12). And the elastic contact part 88 is urged | biased below by the force which the elastic contact part 88 tries to restore | restore from elastic deformation.

  The first embodiment has an advantage that the biasing force to 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, since 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 the guide by the focus plate support frame 60 and the guide pin 80, There is an advantage that a moment in the rotational direction (a force to tilt in the front-rear direction) hardly acts on the shock absorbing member 72.

  As mentioned above, although this invention was demonstrated based on illustration embodiment, this invention is not limited to illustration 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 members forming the (guide hole 77) and the protrusion (guide pin 80) can be reversed. In addition, since the vertical plate portion 73 of the impact absorbing member 72 and the support wall 79 of the focus plate support frame 60 are thin plates in the front-rear direction, a long hole (guide hole 77) and a protrusion (guide pin 80) are provided. However, when the conditions such as the shape of the shock absorbing member are different, as a structure for supporting the shock absorbing member movably, a guide shaft and a guide hole, a groove and a convex portion of a concave cross section, etc. Various structures other than the long hole and the protrusion can be adopted.

  The mirror shock absorbing member of the embodiment has a structure in which an elastic shock absorber 84 is attached to the lower part of a plate-like shock absorbing member 72 bent at a plurality of locations, and the elastic shock absorber 84 enhances the quietness at the time of mirror contact. However, the mirror impact absorbing member to which the present invention is applied is not limited to this. For example, it is also possible to employ a mirror impact absorbing member in a form that does not include a portion corresponding to the elastic buffer 84.

  In each embodiment, the coil spring 82 and the leaf spring 85 are alternatively used as the biasing member that biases the mirror shock absorbing member. However, the coil spring 82 and the leaf spring 85 can be used in combination. In addition to the coil spring 82 and the plate spring 85 spring, any urging member can be used. 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 the main mirror M1 and the sub mirror M2, the present invention can also be applied to a movable mirror of the type including only the main mirror M1.

  The single-lens reflex camera 10 of the embodiment is a so-called digital camera that uses the image sensor 22 as a light-receiving unit for photographing. However, 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 SLR 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 detection device 16 Image sensor (photographing light receiving unit)
20 Focus plate 21 Transmission liquid crystal (transmission 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 portion 48 Bridge portion 49 Axial support portion 50 Prism support frame 51 Lens holding portion 52 Prism support surface 53 Dustproof cushion 54 Light shielding frame 55 Dustproof cushion 56 Field 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 Engaging / disengaging part 67a Through hole 67b Taper part 68 Engagement piece 69 Fixing screw 70 Lock projection 71 Focus plate washer 72 Shock absorbing member ( Mirror shock absorbing member)
73 Vertical plate (moving support mechanism, second wall)
74 Lower plate portion 75 Upper plate portion 76 Spring receiving seat 77 Guide hole (moving support mechanism, long hole)
78 Access hole 79 Support wall (moving support mechanism, first wall)
80 Guide pin (moving support mechanism, protrusion)
80a guide portion 80b retaining portion 81 snap ring 82 coil spring (biasing member)
83 Spring insertion hole 84 Elastic buffer (mirror shock absorbing member)
85 Leaf spring (biasing member)
86 Fixing portion 87 Base portion 88 Elastic contact portion 89 Rivet M1 Main mirror M2 Sub mirror OA Optical axis of photographing lens system

Claims (9)

Moveable between 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 unit without being reflected. A movable mirror,
A focusing plate constituting the observation optical system;
A focus plate support member for supporting the focus plate;
A mirror impact absorbing member that abuts the movable mirror and absorbs an impact when the movable mirror moves from the first position to the second position;
The mirror impact absorbing member is positioned on the subject side from the center of the focusing plate in a direction along the optical axis of the imaging optical system, and is supported by the focusing plate support member so as to be movable in the thickness direction of the focusing plate. An imaging apparatus characterized by being configured.   A moving support mechanism for supporting the mirror impact absorbing member so as to be movable in the plate thickness direction of the focus plate with respect to the focus plate support member with respect to the focus plate in a direction along the optical axis of the photographing optical system. The imaging apparatus according to claim 1, wherein the imaging apparatus is located on a subject side. The moving support mechanism is
A first wall portion provided on the focus plate support member and positioned on the subject side of the focus plate in a 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 impact absorbing member;
A long hole provided in one of the first wall and the second wall and oriented in the longitudinal direction in the moving direction of the mirror shock absorbing member relative to the focus plate support member;
The imaging apparatus according to claim 2, further comprising: a projection protruding from the other of the first wall portion and the second wall portion and slidably inserted into the elongated hole.   4. A biasing member that biases the mirror impact absorbing member in a direction opposite to a pressing direction by the movable mirror when the movable mirror moves from the first position to the second position. The imaging device according to any one of the above. The focus plate support member is rotatably supported with respect to the fixed member,
A support plate portion 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 with and disengaged from the focus plate support member. A lock member that engages the focus plate support member to determine a support position of the focus plate by the focus plate support member,
The imaging device according to claim 4, wherein the biasing member is at least one coil spring whose one end abuts on the support plate portion of the lock member and whose other end abuts on the mirror impact absorbing member.   The imaging device according to claim 5, 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 fixed member,
5. The at least one leaf spring having a base portion supported by the mirror shock absorbing member and an elastically deformable elastic contact portion that protrudes from the base portion and contacts the fixed member. The imaging device described.   The imaging device according to claim 5, wherein the fixing member has a cutout portion that accommodates at least a part of the mirror impact absorbing member. The observation optical system is fixedly supported by the fixed member, transmits the subject light when the movable mirror is at the first position, and displays information on an observed image. Equipped with a transparent indicator,
The imaging apparatus according to claim 5, wherein a position of the focus plate is determined by contact with the transmissive display in a state where the focus plate is supported by the focus plate support member.

Images