JP2009192595A - Mirror mechanism for af single lens reflex camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mirror mechanism for an AF single lens reflex camera capable of effectively preventing luminous flux intruding into a finder from advancing to photographic luminous flux when opening operation of a shutter is performed. <P>SOLUTION: An auxiliary light shielding member 42 operated interlocked with sub mirror devices 38 and 40 is provided separately from the sub mirror devices. When a main mirror device exists at a photographing position, the back surface of the main mirror is shielded from light by the sub mirror devices and the auxiliary light shielding member. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mirror mechanism of an AF single-lens reflex camera.

As a prior art of a mirror mechanism of an AF single-lens reflex camera, one having a main mirror device and a sub mirror device that move in conjunction with each other is known. The main mirror device includes a mirror support frame made of a non-translucent material having an opening at the center, and a main mirror composed of a half mirror supported on the mirror support frame so as to close the opening. On the other hand, the sub mirror device includes a sub mirror support frame made of a non-translucent material and a sub mirror supported by the sub mirror support frame.
When the shutter is not in operation, the main mirror interferes with the photographic light beam that passes through the photographic lens toward the image plane, reflects a part of the photographic light beam toward the viewfinder optical system, and the remaining photographic images that have passed through the main mirror A light beam passes through the opening. On the other hand, the sub-mirror reflects the part of the photographic light beam transmitted through the opening toward the light receiving element for AF distance measurement.
When the shutter is actuated and opened, the main mirror device is temporarily retracted to the viewfinder optical system side so as not to interfere with the photographing light beam, and the sub mirror moves to a position for closing the opening.
Publication country: Japan, Publication name: Photo Industry 82, Publisher: Photo Industry Publishing Co., Ltd., Publication date: February 1, 1982, Number: February issue, Page: 72nd page

  In recent years, the opening of the main mirror device has become larger with the expansion of the AF distance measurement range. Therefore, in order to completely prevent the finder intruding light beam from moving toward the photographing light beam when the shutter is opened, the sub mirror It is necessary to enlarge the support frame.

  However, if the size of the sub mirror support frame is increased, the sub mirror support frame interferes with other members (for example, shutter curtains) positioned closer to the image plane than the sub mirror disposed in the camera body when the shutter is not operated. There is a fear, but since it is difficult to increase the size of these members, there is a limit to increasing the size of the submirror. Further, in a digital camera, a shutter (shutter curtain) positioned on the subject side of the mirror mechanism tends to be disposed closer to a low-pass filter or an image sensor positioned on the imaging plane side of the mirror mechanism. The space provided in the direction of the optical axis is small, so the above problems are more likely to occur.

  An object of the present invention is to provide a mirror mechanism of an AF single-lens reflex camera that can effectively prevent a finder intruding light beam from entering a photographing light beam during a shutter opening operation without increasing the size of a sub mirror support frame.

  The mirror mechanism of the AF single-lens reflex camera of the present invention has a main mirror comprising a main mirror support frame having an opening, and a half mirror supported by the main mirror support frame in a manner to close the opening, and A main mirror device that can move between an observation position at which the main mirror reflects the photographic light beam and guides it to the finder optical system and a photographic position that does not interfere with the photographic light beam, and when the main mirror device is at the observation position. And a sub-mirror device for reflecting a part of the photographic light beam transmitted through the main mirror toward the AF ranging light-receiving element, in a mirror mechanism of an AF single-lens reflex camera, the sub-mirror device separately from the sub-mirror device An auxiliary light shielding member that operates in conjunction with the sub mirror device and the auxiliary light shielding member when the main mirror device is at the photographing position. By the wood to shield the back side the main mirror, the light flux from the finder optical system is characterized in that to prevent the ingress to the photographing light beam through the main mirror and the aperture.

  One end of the sub mirror device is supported on the main mirror support frame so as to be rotatable about an axis extending in the width direction of the camera, and the sub mirror support frame. It is practical to include a sub-mirror that reflects toward the light receiving element for distance.

  When the auxiliary light shielding member and the rear end of the sub-mirror device are pivotally mounted so as to be rotatable about an axis extending in the width direction of the camera, and when the main mirror device is at the observation position, the entire auxiliary light shielding member is connected. It is preferable to be positioned closer to the subject than the image plane.

  One end of the link member is pivotally attached to the auxiliary light shielding member so as to be rotatable about an axis parallel to the axis, and the other end of the link member is rotatable to the main mirror support frame around an axis parallel to the axis. It may be pivotally attached to.

  According to the present invention, it is possible to obtain a mirror mechanism of an AF single-lens reflex camera that can effectively prevent a viewfinder intruding light beam from entering a photographing light beam during a shutter opening operation without increasing the size of the sub mirror device.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. 1 is based on FIG. 1, the left side (subject side) of FIG. 1 is “front”, the right side (imaging plane side) is “rear”, and the upper and lower sides are as shown in FIG. . The left and right are the left and right directions when the camera (digital camera) is viewed from the front.
FIG. 1 shows a mirror mechanism 20 disposed in a camera body (not shown) of an AF single-lens reflex digital camera and its peripheral members. As shown in FIG. 1, a box-shaped metal mirror box 10 is disposed in the camera body, and an opening 12 is formed in the ceiling plate 11 of the mirror box 10. The bottom plate 13 has an opening 14 smaller than the opening 12. Further, an opening 16 is formed in the front plate 15. A photographing lens (not shown) is disposed in front of the front plate 15, and the optical axis OA of the photographing lens coincides with the central axis A of the opening 16. As shown in FIG. 1, a finder optical system L1 (refer to a virtual line) made of an optical element is disposed above the opening 12, and an upper part of the back surface of the camera body faces the finder optical system L1. A finder window F (see virtual line) is provided. The finder optical system L1 and the finder window F are components of the finder.

  The space surrounded by the left and right side plates 17 (see FIGS. 1 and 2; only one side plate is shown in these drawings), the front plate 15, the ceiling plate 11, and the bottom plate 13 is provided with the mirror mechanism 20. The opening 18 is provided in the back surface of the mirror box 10. A hollow shutter case 19 is fixed to the rear surface of the mirror box 10, and openings 19a1 and 19b1 that are smaller than the opening 18 and concentric with each other are formed in the front plate 19a and the rear plate 19b of the shutter case 19, respectively. Has been. A known shutter curtain (shutter) S is disposed between the front plate 19a and the rear plate 19b. The shutter curtain S is composed of a plurality of plates, and one of the left and right ends of each plate is supported by the rear plate 19b. As is well known, the shutter curtain S is provided with spring means for urging the shutter curtain S in the fully open direction, and the shutter curtain S is brought into the fully closed state shown in FIG. Is retained. When a shutter button (not shown) provided on the camera body is pressed, the shutter curtain is unlocked by the stopper in conjunction with the movement of the shutter button, and the shutter curtain S is fully opened by the biasing force of the spring means. After a lapse of a certain time, a rotation signal is sent from a CPU (control means) provided in the camera body to a shutter drive motor (not shown), and the shutter curtain S is fully closed by the rotational force of the shutter drive motor. The stopper returns to hold the shutter curtain S in the fully closed state.

Although not shown, an imaging surface (imaging surface) of the imaging element is located behind the shutter curtain S.
An AF ranging light-receiving element B including a plurality of lenses L2 is disposed immediately below the opening 14. This AF ranging light receiving element B is one of the components of a known AF ranging means. When the AF ranging light receiving element B receives light, the AF ranging means performs distance measurement.

Next, the mirror mechanism 20 will be described in detail mainly with reference to FIGS. 5-10, illustration of a part of link member is abbreviate | omitted.
A pivot pin 22 extending in the left-right direction (the width direction of the AF single-lens reflex camera) protrudes from one end of the surface of the pair of left and right link members 21 facing the side plate 17. The side plates 17 are supported so as to be rotatable around their respective axes. At the other ends of the left and right link members 21, projecting pieces 24 extending from the left and right side portions of the main mirror support frame 23 are rotatably supported around the pivot pin 25 by pivot pins 25 extending in the left and right direction. Yes. As shown in FIGS. 1, 6, 8, 9, and 10, a rectangular recess is formed on the front surface of the main mirror support frame 23 made of a non-translucent material. An opening 26 is provided on the bottom surface of the part. A main mirror 27 that is substantially the same shape as the recess and has a half mirror on the entire surface is fitted and fixed to the recess (the main mirror device is constituted by the main mirror support frame 23 and the main mirror 27). . One pair of left and right link members 29 project from the pair of left and right projecting pieces 28 projecting from the rear ends of the left and right side portions of the main mirror support frame 23, respectively. It is pivotally mounted so that it can rotate around 30. Left and right pivot pins 31 project from the other end of the left and right link members 29 facing the side plates 17, and both pivot pins 31 are respectively pivoted on the left and right side plates 17. Is rotatably supported. A link member 33 is located on the left side of the main mirror support frame 23, and one end of the link member 33 is one end of a link member 35 located on the left side of the main mirror support frame 23 via a pivot pin 34 extending in the left-right direction. It is pivotally mounted as a rotatable. A support hole 36 is formed in the other end of the link member 35, and a support pin 37 (see FIGS. 1 to 3) that protrudes to the right from the left side plate 17 is fitted into the left and right support holes 36. Thus, the link member 35 is supported by the left side plate 17 so as to be rotatable around the support pin 37.

A sub-mirror support frame 38 made of a non-translucent material is positioned directly below the main mirror support frame 23, and the other end of the link member 33 (the pivot pin 34 is located at the rear end of the left side of the sub-mirror support frame 38. The end of the main mirror support frame 23 is fixed to the left side of the main mirror support frame 23 by a pivot pin 32 extending in the left-right direction. It is attached so that it can rotate around 32. As shown in FIGS. 5 and 6, a sub-mirror 40 smaller in size than the sub-mirror support frame 38 is bonded and fixed to the front surface of the sub-mirror support frame 38 (a sub-mirror device is constituted by the sub-mirror support frame 38 and the sub-mirror 40. ing). A pair of left and right protrusions projecting from the rear end portion of the auxiliary light shielding member 42 extending in the left-right direction are provided at the lower end portions (rear end portions) of the left and right side surfaces of the sub-mirror support frame 38 by pivot pins 41 extending in the left-right direction. Each of the pieces 43 is supported so as to be rotatable around a horizontal axis. Further, the lower end portions of the pair of left and right link members 45 are supported at the front end portions of the left and right side surfaces of the auxiliary light shielding member 42 so as to be rotatable around the pivot pins 44 by pivot pins 44 extending in the horizontal direction. Yes. The upper end portions of the left and right link members 45 are respectively supported on the left and right sides of the main mirror support frame 23 so as to be rotatable around the pivot pin 46 by pivot pins 46 extending in the left-right direction.
Thus, the four-link mechanism is constituted by the pivot pin 32, the pivot pin 41, the pivot pin 44, the pivot pin 46, the main mirror support frame 23, the sub mirror support frame 38, the auxiliary light shielding member 42, and the link member 45. It is configured.

  Although not shown, the left (or right) pivot pin 22 passes through the left (or right) side plate 17 and protrudes to the left (or right side) of the side plate 17. A pinion gear is fixed to the tip of 22. The pinion gear is linked to a pinion gear fixed to an output shaft of a mirror driving motor provided in the camera body via a gear train. Further, the mirror driving motor is electrically connected to the CPU, and when the CPU sends a signal to the mirror driving motor, the mirror driving motor rotates and the pivot pin 22 rotates.

An AF single-lens reflex camera including the mirror mechanism 20 having the above-described configuration operates as follows.
When the shutter button provided on the camera body is not pressed, the mirror mechanism 20 is in the initial state shown in FIGS. 1, 2, 5, and 8, and the main mirror support frame 23 and the main mirror 27 pass through the photographing lens. Thus, it is located in the photographic light beam O toward the image plane (see FIGS. 1 and 2. The position of the main mirror 27 at this time is the observation position). As shown in FIG. 1, a part of the photographing light beam O is reflected upward by the main mirror 27 and guided to the finder optical system L1 through the opening 12. On the other hand, the remaining portion of the photographic light beam O is transmitted through the main mirror 27 and the opening 26 formed of a half mirror, reflected downward by the sub mirror 40, and received by the AF ranging light receiving element B through the opening 14. . Thus, when the mirror mechanism 20 is in the initial state, the photographing light beam O does not reach the shutter curtain S.

  When the shutter button is fully pressed in this state, the CPU detects this and sends a rotation signal to the mirror driving motor. Upon receiving the signal, the mirror driving motor rotates in the forward direction and rotates the pivot pin 22 counterclockwise in FIGS. Then, as shown in FIGS. 3, 6 and 9, the link member 21 rotates counterclockwise about the pivot pin 22, and the link member 33 and the link member 35 which are arranged in a substantially straight line in a side view. Becomes substantially V-shaped. The sub mirror support frame 38 and the link member 45 rotate clockwise around the pivot pin 32 and the pivot pin 46, respectively, and the link member 29 rotates counterclockwise around the pivot pin 31.

When the mirror driving motor continues to rotate further forward, the mirror mechanism 20 is in the flipped-up state shown in FIGS. 4, 7, and 10, and as shown in FIG. 4, the main mirror support frame 23, the main mirror 27, and the sub mirror support The frame 38, the sub mirror 40, and the auxiliary light shielding member 42 are all retracted from the photographing light beam O and are located immediately below the finder optical system L1 (the position of the main mirror 27 at this time is the photographing position). Accordingly, the photographing light beam O reaches the shutter curtain S through the opening 19a1.
At this time, as shown in FIGS. 4 and 7, the sub mirror support frame 38 is positioned directly below the main mirror 27 while being substantially parallel to the main mirror support frame 23. Further, the auxiliary light shielding member 42 is substantially aligned with the sub mirror support frame 38 in a side view, and the auxiliary light shielding member 42 located immediately before the sub mirror 40 is located immediately below the main mirror 27 (substantially parallel to the main mirror 27). ).

  As shown in FIG. 11, when the mirror mechanism 20 at this time is viewed from below, the opening 26 of the main mirror support frame 23 overlaps the sub mirror device (the sub mirror support frame 38 and the sub mirror 40) and the auxiliary light shielding member 42 in the vertical direction. . Therefore, a harmful finder intruding light beam FO (see FIG. 1) enters the camera body from the outside of the AF single-lens reflex camera through the finder window F, passes through the finder optical system L1, the main mirror 27, and the aperture 26 toward the photographing light beam O side. 11 is shaded completely by the sub mirror device (sub mirror support frame 38 and sub mirror 40) and the auxiliary light shielding member 42. Specifically, the auxiliary light shielding member 42 shields the front end portion of the finder intruding light beam FO, and the sub mirror device (sub mirror support frame 38 and sub mirror 40) shields the portion excluding the front end portion.

  When the shutter button is fully pressed as described above, the stopper releases the locking of the shutter curtain S in conjunction with this movement, and the shutter curtain S is fully opened by the biasing force of the spring means. Therefore, when the mirror mechanism 20 is in the flip-up state shown in FIGS. 4, 7, and 10, and the finder intruding light beam FO is completely prevented from entering the photographing light beam O, the photographing light beam O is in the shutter case 19. The image pickup surface of the image pickup element picks up images through the openings 19a1 and 19b1. When a predetermined time elapses after the shutter curtain S is fully opened, the CPU sends a signal to the shutter drive motor, rotates the shutter drive motor, and returns the shutter curtain S to the fully closed state. Further, after the shutter curtain S is fully closed, a rotation signal is sent from the CPU to the mirror driving motor, and the mirror driving motor is reversely rotated. Then, the mirror mechanism 20 performs an operation opposite to the above operation, and the mirror mechanism 20 returns to the initial state shown in FIGS. 1, 2, 5, and 8.

  As described above, according to the present embodiment, the entrance of the finder intruding light beam FO into the photographing light beam O is completely prevented by the sub mirror device (the sub mirror support frame 38 and the sub mirror 40) and the auxiliary light shielding member 42 when the shutter is operated. Further, as shown in FIGS. 1 to 4 and 11, the sub-mirror device and the auxiliary light shielding member 42 prevent the finder intruding light beam FO from entering the photographing light beam O. Compared with the case where the light beam FO is prevented from entering the photographing light beam O only by a sub-mirror device (a sub-mirror device having a size obtained by adding the sub-mirror support frame 38 and the auxiliary light-shielding member 42, not shown), the sub-mirror device has longitudinal dimensions. Can be shortened. In addition, as shown in FIGS. 1 to 4, the auxiliary light shielding member 42 is always located closer to the subject side than the shutter curtain S regardless of the state of the mirror driving mechanism 20, so that the auxiliary light shielding member 42 is in the mirror mechanism 20. There is no risk of contact with a member (for example, on the shutter curtain S) located behind. Further, even if the mirror box 10 is not enlarged, there is no possibility that the auxiliary light shielding member 42 contacts the mirror box 10, so that it is not necessary to enlarge the mirror box 10.

  In this embodiment, the present invention is applied to a digital AF single-lens reflex camera. However, by replacing the image sensor with a film (in this case, the film surface is an imaging surface), silver is used. Of course, it can be applied to a salt type AF single-lens reflex camera. In addition, when the shutter is a so-called lens shutter, and it is not necessary to consider the light shielding of the image sensor and the film, the shutter may be arranged on the subject side from the mirror mechanism 20. Furthermore, the link mechanism (four-bar link mechanism) that constitutes the mirror mechanism 20 is not limited to the one described above, and may be another structure.

It is a side view of the mirror mechanism of the AF single-lens reflex camera which is one Embodiment of this invention, and its peripheral member. It is a side view of the mirror mechanism when the shutter is not operated. It is a side view of a mirror mechanism immediately after a shutter operation. It is a side view of the mirror mechanism when the movement is completed. It is the perspective view seen from the lower direction at the time of shutter non-operation of a mirror mechanism. It is the perspective view seen from the downward direction immediately after a shutter action | operation of a mirror mechanism. The perspective view seen from the lower part at the time of completion of a movement of a mirror mechanism. It is the perspective view seen from the upper direction at the time of shutter non-operation of a mirror mechanism. It is the perspective view seen from the upper direction immediately after a shutter action | operation of a mirror mechanism. The perspective view seen from the upper part at the time of completion of a movement of a mirror mechanism. It is a bottom view for showing the positional relationship of the main mirror, the sub mirror, and the auxiliary light shielding member when the movement of the mirror mechanism is completed.

Explanation of symbols

10 Mirror box 11 Ceiling plate 12 Opening 13 Bottom plate 14 Opening 15 Front plate 16 Opening 17 Side plate 18 Opening 19 Shutter case 19a Front plate 19b Rear plate 19a1 19b1 Opening 20 Mirror mechanism 21 Link member 22 Pivoting pin 23 Main mirror support frame (main Mirror device)
24 Projection piece 25 Pivoting pin 26 Opening 27 Main mirror (main mirror device)
28 Projection piece 29 Link member 30 Pivot pin 31 Pivot pin 32 Pivot pin 33 Link member 34 Pivot pin 35 Link member 36 Support hole 37 Support pin 38 Sub mirror support frame (sub mirror device)
40 Submirror (Submirror device)
41 Pivoting Pin 42 Auxiliary Shading Member 43 Projection Piece 44 Pivoting Pin 45 Link Member 46 Pivoting Pin A Center Axis B of Opening 16 AF Distance Receiving Element L1 Finder Optical System L2 Lens O Shooting Light Beam OA Optical Axis S Shutter Curtain (shutter)

Claims (4)

A main mirror support frame having an opening, and a main mirror composed of a half mirror supported by the main mirror support frame so as to close the opening, and the main mirror reflects a photographic light beam and finder optics A main mirror device that is movable between an observation position that leads to the system and an imaging position that does not interfere with the imaging light flux;
In a mirror mechanism of an AF single-lens reflex camera having a sub-mirror device that reflects a part of the photographic light beam that has passed through the main mirror toward the AF distance-receiving element when the main mirror device is at the observation position. ,
In addition to the sub-mirror device, an auxiliary light-shielding member that operates in conjunction with the sub-mirror device is provided. When the main mirror device is at the photographing position, the sub-mirror device and the auxiliary light-shielding member shield the back surface of the main mirror. And a mirror mechanism for an AF single-lens reflex camera that prevents the light beam from the finder optical system from entering the photographing light beam through the main mirror and the opening. In the mirror mechanism of the AF single-lens reflex camera according to claim 1,
One end of the sub mirror device is supported on the main mirror support frame so as to be rotatable about an axis extending in the width direction of the camera, and is supported by the sub mirror support frame. A mirror mechanism of an AF single-lens reflex camera, comprising: a sub-mirror that reflects toward the light receiving element for distance. In the mirror mechanism of the AF single-lens reflex camera according to claim 1 or 2,
When the auxiliary light shielding member and the rear end of the sub-mirror device are pivotally mounted so as to be rotatable about an axis extending in the width direction of the camera, and when the main mirror device is at the observation position, the entire auxiliary light shielding member is connected. A mirror mechanism of an AF single-lens reflex camera located on the subject side from the image plane. In the mirror mechanism of the AF single-lens reflex camera according to any one of claims 1 to 3,
One end of the link member is pivotally attached to the auxiliary light shielding member so as to be rotatable about an axis parallel to the axis, and the other end of the link member is rotatable to the main mirror support frame around an axis parallel to the axis. The mirror mechanism of an AF single-lens reflex camera pivotally attached to the camera.

Images