JP5863251B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging device including a main mirror and a sub mirror.

  In a single-lens reflex camera, a mirror box is disposed between an imaging lens and an image plane such as a CCD sensor or a CMOS sensor. A mirror unit composed of a main mirror unit and a sub mirror unit is attached to the mirror box. The main mirror unit includes a main mirror and a main mirror holder, and the sub mirror unit includes a sub mirror and a sub mirror holder. The main mirror holder is rotatably mounted in the mirror box, and the sub mirror holder is rotatably mounted on the main mirror holder. The main mirror unit is normally located at the finder observation position, and guides the light beam incident from the imaging lens to the finder optical system. When a release button or the like is pressed at the time of shooting, the finder observation position is rotated to the exposure retracting position in conjunction with this, and the shutter returns to the observation position after the shutter operation is completed. When the main mirror unit is located at the finder observation position, the sub mirror unit is located at a reflection position where the light beam transmitted through the main mirror unit is reflected toward the focus detection device. When the main mirror unit rotates from the viewfinder observation position to the exposure retract position, the sub mirror unit rotates from the reflection position to a position overlapping the main mirror unit. When the main mirror unit is in the exposure retracting position and the sub mirror unit is in a position overlapping the main mirror, the tip of the sub mirror holder collides with the back surface of the main mirror holder that holds the main mirror.

  On the other hand, in a single-lens reflex camera, in order to suppress unnecessary reflection inside the mirror box in order to obtain a high-quality image, it is common to perform mat processing on components inside the mirror box.

  Patent Document 1 discloses a configuration in which an impact absorbing member is disposed between a main mirror holder and a sub mirror holder so as to absorb an impact generated when the sub mirror overlaps the main mirror.

JP 2009-098380 A

  However, in the configuration in which the buffer member is disposed between the main mirror holder and the sub mirror holder as described above, the buffer member is required. In addition, the shock absorbing member deteriorates while repeating the collision, and generates abrasion powder. There is a problem that the wear powder causes dust inside the camera. In order to reduce the cost, it may be possible to eliminate the buffer member. However, in this case, the uneven portion formed on the surface of the main mirror holder and the uneven portion formed on the surface of the sub mirror holder repeatedly collide with each other to prevent irregular reflection, and each uneven portion is worn. This also causes a problem that abrasion powder is generated and causes dust inside the camera.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide an imaging apparatus that suppresses wear of the main mirror holding member and the sub mirror holding member without adding parts such as a buffer member. Is to propose.

Imaging apparatus of the present invention is an imaging apparatus provided with a moving mirror unit between a finder observation position and exposure retracted position, when the mirror unit is located in the finder observation position, a part of the imaging beam the by reflecting-out guide to the finder optical system, a first mirror semipermeable which transmits the remainder of the imaging light beam, a first holding member for holding the first mirror, the first mirror A second mirror that is rotatably arranged and reflects the remainder of the imaging light flux that has passed through the first mirror at the finder observation position and guides it to a focus detection device, and a second mirror that holds the second mirror. 2, and the first holding member is located on the opposite side of the surface holding the first mirror and when the mirror unit is located at the exposure retract position, Does not contact the holding member has a first region and said second holding member that abuts the second region, the first region is formed in a surface to prevent reflection, the first The second region is characterized by being formed with a flatter surface than the first region.

According to the present invention, it is repeated to move the mirror unit between a finder observation position and exposure retracted position, it is possible to reduce the wear of the contact area between the first holding member and second holding member And the generation of dust inside the camera can be suppressed.

FIG. 1 is a cross-sectional configuration diagram illustrating an arrangement of an imaging apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional configuration diagram illustrating a state at the mirror-up position of the imaging apparatus according to the embodiment of the present invention. FIG. 3 is an explanatory view of the mirror device according to the embodiment of the present invention as viewed from below. FIG. 4 is an explanatory view of the mirror holder of the present invention as seen from the back side. FIG. 5 is a schematic diagram showing shielding of external light from the finder optical system of external light of the imaging apparatus of the present invention. FIG. 6 is an explanatory diagram showing a state of the mirror device of the present invention at the mirror down position. FIG. 7 is an explanatory diagram showing the state of the mirror up position of the mirror device of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  Hereinafter, an imaging apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

  1 and 2 are cross-sectional configuration diagrams showing an outline of a single-lens reflex camera to which a mirror unit 9 according to an embodiment is applied.

  In the digital single-lens reflex camera of this embodiment, a subject image is photoelectrically converted by an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide). After the photoelectric change, image information is generated and the image is recorded on an electronic recording medium such as an arbitrary memory.

  In a single-lens reflex camera, a mirror unit 9 equipped with a main mirror unit 10 and a sub mirror unit 21 is disposed in a mirror box 3 between a mount 1 and a shutter 2.

  In the apparatus configuration shown in FIG. 1, the main mirror unit 10 is rotatably supported on the mirror box 3 by rotating shafts 11 projecting on both sides, and is in a mirror down position and an exposure retreat position that are finder observation positions. It is possible to switch between a certain mirror-up position. The main mirror unit 10 in the mirror-down position is restricted from rotating by the main mirror restricting pin 4 and is inclined in front of the shutter 2 and the image sensor 5. The main mirror unit 10 at this mirror-down position reflects the imaging light beam that has passed through the opening of the mount 1 upward and guides it to the finder optical system 6.

  As shown in FIG. 2, the main mirror unit 10 in the mirror-up position is in a position that is flipped upward and deviated from the photographing optical path.

  The sub mirror unit 21 is rotatably supported on the main mirror unit 10 by the rotary shaft 12 and is rotatable between a mirror down position and a mirror up position. The sub mirror unit 21 at the mirror down position is restricted from rotating by the sub mirror restricting pin 7 and is inclined to the back side of the main mirror unit. The sub mirror unit at this mirror down position guides the transmitted light beam transmitted through the main mirror unit to the AF unit (focus detection device) 8.

  The sub mirror unit 21 in the mirror up position is rotated to the main mirror unit 10 side and is located at a position overlapping the main mirror unit 10. In this state, the main mirror unit 10 and the sub mirror unit 21 are at positions deviating from the imaging optical path, so that the light flux that has passed through the opening of the mount 1 is guided to the imaging element 5. Further, when in the mirror up position, the mirror unit 9 also serves to shield external light incident from the finder optical system 6.

  Details of the mirror unit 9 will be described with reference to FIGS. 3 and 4. FIG. 3 is an explanatory view of the mirror device viewed from obliquely below, and FIG. 4 is an explanatory view of the main mirror holder viewed from the back side.

  The main mirror unit 10 includes a main mirror (first mirror) 13 and a main mirror holder (first holding member) 14.

  The main mirror is a semi-transparent half mirror. When the main mirror unit 10 is located at the mirror down position, a part of the light beam of the subject that has passed through the opening of the mount 1 is reflected upward and guided to the finder optical system 6, and the remaining light beam passes through the sub mirror unit 21. To the distance measuring unit 8.

  The main mirror holder 14 holds the main mirror 13 on the front side. The main mirror holder 14 is pivotally supported on the mirror box 3 by rotating shafts 11 projecting from both sides. A drive shaft 15 for driving the main mirror unit 10 by a drive mechanism (not shown) protrudes from one side surface of the main mirror holder 14.

  A light-shielding wall (protrusion) 16 protrudes from the tip of the main mirror holder 14 on the back side (opposite side) on the subject side. In the vicinity of the light shielding wall, when the mirror unit 9 is positioned at the mirror up position, a tip end portion 26 of a sub mirror holder (second holding member) 23 that holds the sub mirror (second mirror) 22 of the sub mirror unit 21 and It has a contact area (second area) 17 for contact. A region (first region) 18 other than the contact region 17 is subjected to an antireflection mat treatment, and the contact region 17 is formed with a flatter surface than the region 18. The surface roughness is mainly represented by arithmetic average roughness, maximum height, ten-point average roughness, etc. In this example, the surface of the region 18 is finished to 13-15 μm with a ten-point average roughness. (Japan Etching Honing No. 9 equivalent). Further, the contact region 17 has a rectangular shape because it contacts the entire tip portion 26 of the sub mirror holder 23. Naturally, at this time, the entire tip side of the sub mirror holder 23 is in contact with the contact region 17. When the contact region 17 contacts the entire tip portion 26, unnecessary reflection can be suppressed and stress during contact can be dispersed.

  FIG. 5 shows how the mirror unit 9 blocks the external light 100 from the viewfinder optical system 6. External light incident from the finder optical system 6 reaches the mirror unit 9 through the focus plate 32. When there is no light shielding wall 16, the diffused light on the focusing plate 32 and the light beam reflected on the surface of the sub mirror 22 and the mirror holder inside the mirror unit 9 are reflected by the imaging lens 31 and reach the imaging device 5, and the captured image is May deteriorate. The unnecessary light can be blocked by the light blocking wall 16.

  The sub mirror unit 21 has a sub mirror 22 and a sub mirror holder 23.

  The sub mirror 22 is a total reflection mirror. When the sub mirror unit 21 is located at the mirror down position, the light beam transmitted through the main mirror 13 formed of a half mirror is reflected downward and guided to the distance measuring unit 8.

  The sub mirror holder 23 holds the sub mirror 22 on the front side. A protrusion 24 that protrudes from the main mirror holder 14 is formed on the side surface of the sub mirror 22. The protrusion 24 is rotatably supported by the rotation shaft 12 on the side surface of the main mirror holder 14.

  6 and 7 are explanatory diagrams showing the mirror device in the mirror-down state and the mirror-up state, respectively.

  The sub mirror holder 23 can be biased in the opening direction and the closing direction with respect to the main mirror holder 14 by the toggle spring 30. The toggle spring 30 is supported by the protrusion 19 on the side of the main mirror holder 14. One end of the toggle spring 30 is in contact with the front groove portion 20 of the main mirror holder 14, and the other end is in contact with the groove portion 25 formed in the protruding portion 24 of the sub mirror holder 23.

  When the mirror unit 9 is located at the mirror down position, the sub mirror unit 21 is biased in the opening direction by the toggle spring 30. On the other hand, when the mirror unit 9 is located at the mirror up position, the biasing direction of the toggle spring 30 is reversed, and the tip of the sub mirror unit 21 is biased in the closing direction. By this urging in the closing direction, the front end of the sub mirror unit 21 is rotated toward the main mirror unit 10, and the front end portion 26 of the sub mirror holder collides with the contact area 17 on the back side of the main mirror holder 14 and stops.

  In the mirror unit 9 of the embodiment, the contact region 17 whose surface is smoother than the other region on the back side of the main mirror holder and the tip portion 26 of the sub mirror holder 23 collide with each other. Therefore, even if the number of times of release increases, wear due to collision between the main mirror holder 14 of the main mirror unit 10 and the sub mirror holder 23 of the sub mirror unit 21 can be suppressed.

  Further, since the contact area 17 is arranged in the vicinity of the light shielding wall 16 of the main mirror holder, the reflection at the contact area 17 does not adversely affect the performance of the camera.

  In the above-described mirror device, the example in which the contact area 17 of the main mirror holder has a smoother surface shape than the other areas has been described. However, the contact area is unpainted and the other areas are matted. It may be a configuration.

13 Main mirror 14 Main mirror holding member 17 Contact area 22 Sub mirror 23 Sub mirror holding member

Claims (4)

An imaging apparatus comprising a moving mirror unit between a finder observation position and exposure retracted position,
When the mirror unit is located in the finder observation position, guide-out to the finder optical system by reflecting a portion of the imaging light beam, a semi-permeable first mirror that transmits the remainder of the imaging light beam,
A first holding member for holding the first mirror;
A second mirror that is rotatably arranged on the first mirror , and reflects the remainder of the imaging light flux that has passed through the first mirror at the finder observation position and guides it to a focus detection device;
A second holding member for holding the second mirror,
The first holding member does not come into contact with the second holding member when the mirror unit is located at the exposure retracted position on the side opposite to the surface holding the first mirror. has a region and the second holding member that abuts the second region,
The first region is formed by a surface that prevents reflection,
The image pickup apparatus, wherein the second region is formed with a flatter surface than the first region. The first holding member shields light so that a light beam incident from the finder optical system and reflected inside the imaging apparatus does not reach the imaging element when the mirror unit is located at the exposure retracted position. Part is formed,
The imaging apparatus according to claim 1, wherein the second region is formed in the vicinity of the light shielding portion.   The imaging apparatus according to claim 1, wherein the second region has a rectangular shape that abuts the entire side of the tip on the subject side in the second holding member.   2. The image pickup apparatus according to claim 1, wherein the first area is matted and the second area is not matted. 3.