JP2012137595A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce damage to a shutter blade due to sunlight without giving the shutter blade heat-resistant properties, while using inexpensive materials.SOLUTION: A sub-mirror holding member 112 is configured such that the area is expanded in the downward direction and left-right direction of a camera so as to cover an exposure opening 5d of a shutter device 5 to thereby prevent sunlight from reaching the shutter blade.

Description

  The present invention relates to an imaging apparatus that separates and focuses imaging light on a focus detection apparatus, and more particularly to a holding member that holds a mirror that reflects a light beam to the focus detection apparatus.

  In so-called single-lens reflex cameras, a shutter device is disposed in the vicinity of the imaging surface. The shutter device is provided with shutter blades for shielding the subject light, and the materials disclosed in Patent Document 1 and various materials described in Patent Document 2 are proposed as the material of the shutter blades. ing.

  On the subject side of the shutter, a mirror unit that retracts from the photographing optical path at the time of exposure is arranged as disclosed in Patent Document 2, and when the photographer looks into the finder and confirms the subject, the subject light is finder portion. The object light reflected by the semi-transmissive mirror (hereinafter referred to as the main mirror) that is separated by the focus detection device at a predetermined ratio is observed. The transmitted subject light is guided to the focus detection device by a total reflection mirror (hereinafter referred to as a sub mirror).

JP 2000-75353 A JP 2007-101784

  However, in the prior art disclosed in the above-mentioned patent documents, the sunlight is focused on the shutter blades when the lens is directed to the sun and passed near the camera lower side of the mirror unit. There was a possibility that the through hole could be opened due to damage from sunlight. For this reason, it is necessary to take measures against heat, such as applying a metal film to the blade on the most object side of the shutter blade, which causes an increase in cost. In addition, although it is a known technique for photometry, it can be expected to have a heat-resistant effect that whitens the blade surface closest to the subject of the shutter blade, but whitening the surface of the shutter blade that has light shielding properties also causes an increase in cost. .

  Although it is desirable that the main mirror holding member that holds the main mirror can block light other than the effective light beam, in order to secure a space necessary for avoidance operation at the time of shooting, there is a size limit at the tip position of the main mirror holding member. There is an area that cannot be shielded from light below the camera.

  In order to achieve the above object, the present invention described in claim 1 is configured to separate the photographing light beam 50 incident from the photographing optical system into reflected light to the finder unit (106, 109) and transmitted light to the focus detection device. One reflective member (101), a second reflective member (102) that reflects the transmitted light from the first reflective member to the focus detection device (107), and control of subject light incident on the image sensor (4) A first holding member (111) holding the first reflecting member (101) and a second holding member (112) holding the second reflecting member (102). In the imaging apparatus configured to be pivotably held and movable to the retracted position during exposure, the second holding member (112) is at least the optical axis center of the exposure opening (5d) of the shutter device (5). It is configured with a larger area than the opening for exposure so as to cover the lower area of the imaging device. It is a feature.

  The present invention as defined in claim 2 is the camera according to claim 1, wherein the photographer side surface of the second holding member (112) includes an exposure opening region (112g) of the shutter device (5) and a region other than the exposure opening. Is characterized by comprising different surfaces (112h, 112i).

  The present invention as defined in claim 3 is characterized in that, in claims 1 and 2, the regions (112h, 112i) other than the exposure opening of the shutter device (5) of the second holding member (112) are the opening for exposure. It is characterized by being provided closer to the subject than the region (112g).

  According to a fourth aspect of the present invention, in the third aspect of the present invention, in the region other than the exposure opening of the shutter device (5) of the second holding member (112), the lower tip (112h) of the imaging device has a shutter device. A parallel surface is provided, and a chamfered shape is provided at the left and right end portion (112i).

  According to the present invention, it is possible to select an inexpensive material having no heat resistance measures for the shutter blade member, and to reduce the cost.

1 is an external perspective view of a digital single-lens reflex camera to which the present invention is applied. 1 is a cross-sectional view of a digital single-lens reflex camera to which the present invention is applied. Mirror unit and shutter device external view to which the present invention is applied AA sectional view of FIG. 3 (exposure state) AA sectional view of Fig. 3 (in shooting standby state) BB sectional view of Fig. 3 (shooting standby state) The perspective view of the mirror unit to which this invention is applied

[Example 1]
FIG. 1 is a perspective view of a single-lens reflex camera to which the present invention is applied.

  On the subject side of the camera body 1, there is provided a camera mount 2 for mounting a detachable photographic lens (photographic optical system) (not shown). When the release switch 3 which is a two-stage switch is operated, AE (automatic exposure adjustment) and AF (automatic focus adjustment) are started and photographing is performed. When the release button 3 is lightly pressed, AE and AF are performed, and when the release button 3 is further pressed from this state, an exposure operation is performed.

  FIG. 2 is a cross-sectional view showing a layout of main components of a single-lens reflex camera. The main mirror 101 and the sub mirror 102 are arranged in the photographing optical path as mirror units, and are in a photographing standby state.

  A detachable imaging lens (not shown) is attached to the mount 2, and the imaging light flux 50 that has passed through the imaging lens is reflected at a predetermined ratio by a main mirror 101 that is rotatably attached to the mirror box 100. Is guided to the upper side of the arranged camera. The photographer observes the subject image formed on the focusing screen 106 via the pentamirror 109 and an eyepiece (not shown). The photographing light beam 50 that is not reflected by the main mirror 101 is transmitted through the main mirror 101, reflected by the sub mirror 102, and guided to the focus detection unit 107 below the camera. The focus detection unit 107 includes a condenser lens 107a, a diaphragm 107b, a secondary imaging lens 107c, a focus detection sensor 107d, and the like. The photographic light beam 50 reflected by the sub mirror 102 is incident on the focus detection unit of the focus detection sensor 107d via the above components, thereby performing focus detection.

  A shutter device 5 and an image sensor 4 are arranged on the photographer side of the main mirror 101 and the sub mirror 102.

  FIG. 3 is a view of the mirror unit and the shutter unit as viewed from the object side. FIGS. 4-1 and 4-2 are cross-sectional views taken along the section AA, and FIGS. 4-3 are cross-sectional views taken along the section BB.

  FIG. 5 is a perspective view of the mirror unit in a shooting standby state as viewed from below the camera.

  The shape of the present invention with respect to the vertical direction of the camera will be described with reference to FIGS. 4-1 and 4-2, and the shape of the present invention with respect to the horizontal direction of the camera will be described with reference to FIG. 4-3.

  FIG. 4A is a cross-sectional view showing the arrangement of the main mirror 101 and the sub mirror 102 in the exposure state. The main mirror 101 and the sub mirror 102 are retracted above the camera, and are retracted to positions that do not affect the captured image.

  The main mirror holding member 111 is held at the retracted position by the drive lever 5e, and the sub mirror holding member 112 is biased to contact the main mirror holding member 111 by the sub mirror biasing spring 110, whereby the main mirror holding member 111 is On the other hand, it is kept closed. The closing position of the sub mirror holding member 112 with respect to the main mirror holding member 111 is determined by the position of the contact surface 112a with respect to the main mirror holding member 111. The rotation holding mechanism and the rotation mechanism of the sub mirror holding member 112 with respect to the main mirror holding member 111 are known techniques.

  In the exposure state, the shutter blade 5a disposed in the shutter device 5 is retracted from the exposure opening 5d provided in the subject side shutter member 5b and the photographer side shutter holding member 5c. The photographic light beam 50 passes through the light beam separation low-pass filter 4a and the infrared cut filter 4b, which are optical members provided on the subject side of the image sensor 4, and enters the image sensor 4. An optical image formed by exposure for a predetermined time is converted into an electrical signal and output. In the present embodiment, the optical member set on the subject side of the image pickup device 4 is a low-pass filter for light separation and an infrared cut filter, but the present invention is not limited to this and is set according to the application. May be.

  FIG. 4B is a cross-sectional view illustrating the arrangement of the main mirror 101 and the sub mirror 102 in the shooting standby state.

  The sub mirror 102 is configured to be disposed at a predetermined angle in order to reflect the photographing light beam 50 transmitted through the main mirror 101 in the direction of the focus detection unit 107. The required area of the sub mirror 102 may be smaller than the imaging range because it is sufficient to detect the focus within a predetermined range with respect to the imaging range. In general, since the sub-mirror is formed by vapor-depositing a reflective surface on a glass material, the sub-mirror is formed with a necessary minimum area in consideration of cost. Therefore, the camera lower end of the sub mirror 102 is in the region of the exposure opening 5d of the shutter device 5. The position of the sub mirror 102 closest to the shutter device 5 in the imaging standby state is the lower end of the camera, and the region of the sub mirror holding member 112 that covers the front end of the sub mirror 102 is also closest to the shutter device 5. A first shutter facing surface 112g is provided in a region closest to the shutter device 5 of the sub mirror holding member 112 in the imaging standby state so as to ensure strength while avoiding interference with the shutter device 5. The sub-mirror holding member 112 is close to the subject-side shutter member 5b, but is in the region where the subject-side shutter member 5b does not exist because it is within the range of the exposure opening 5d. An appropriate distance is secured by setting the shutter blade 5a to be substantially parallel to the shutter blade 5a. This avoids interference when the rotation operation is performed by the photographing operation.

  In order to cover the exposure opening 5d of the shutter device 5 with the sub mirror holding member 112 and prevent the harmful light from reaching the shutter blade 5a, the present invention enlarges the camera lower side and the left and right direction of the sub mirror holding member 112. Yes.

  When the first shutter facing surface 112g of the sub-mirror holding member 112 and the opening edge 5b-1 of the exposure opening 5d of the subject-side shutter member 5b are less than a predetermined distance, the sub-mirror holding member 112 is rotated by a shooting operation. May cause interference. For this reason, the second shutter facing surface 112h is provided substantially in parallel with the shutter blade 5a from the region below the predetermined distance to the region below the camera. The second shutter facing surface 112h is a surface set so as to be at least a predetermined distance in the direction of the photographing optical axis from the subject side shutter member 5b. The predetermined distance may be set based on component accuracy and component strength, for example, about 0.50 mm, but is not limited to this value.

  In the present embodiment, the second shutter facing surface 112h is substantially parallel to the shutter blade 5a. However, the present invention is not limited to this, and an appropriate gap is secured for the shutter device 5. Just do it.

  The exposure opening 5d is covered by providing the shape determined by the second shutter facing surface 112h and the abutting surface 112a to the main mirror holding member 111 at the camera lower end of the sub mirror holding member 112.

  The upward direction of the exposure opening 5d on the camera is covered with the main mirror holding member 111, so that no harmful light reaches.

  FIG. 4C is a cross-sectional view illustrating the arrangement of the main mirror 101 and the sub mirror 102 in the photographing standby state on the cross section B-B, and shows the vicinity of the first shutter facing surface 112g of the sub mirror holding member 112.

  When the first shutter facing surface 112g of the sub-mirror holding member 112 and the left-right direction opening edge 5b-2 of the exposure opening 5d of the subject-side shutter member 5b are less than or equal to a predetermined distance, the sub-mirror holding member 112 is rotated by a shooting operation. There is a possibility of interference when moving. Therefore, a chamfered shape that is the third shutter facing surface 112i is provided on the sub-mirror holding member 112 from the outside of the region that is equal to or less than the predetermined distance. The third shutter facing surface 112i is a surface set to be a predetermined distance or more from the subject side shutter member 5b in the photographing optical axis direction. The third shutter facing surface 112i is provided at the left and right ends of the sub mirror holding member 112.

  In the present embodiment, the third shutter facing surface 112i has a chamfered shape, but the present invention is not limited to this, as long as an appropriate gap is secured to the shutter device 5.

  As described above, the sub-mirror holding member 112 is provided with the second shutter facing surface 112h and the third shutter facing surface 112i, thereby covering the exposure opening 5d of the shutter device 5 and ensuring the retracted position during exposure. It becomes possible to do.

  The second shutter facing surface 112h is substantially parallel to the shutter blade 5a, and the third shutter facing surface 112i has a chamfered shape. This is because the exposure opening 5d has a horizontally long shape with respect to the image circle of the photographing light beam 50. This is because the lower side of the camera is easily affected by harmful light incident from other than the shooting angle of view, and it is desirable to take a large amount of overlap when covering the exposure opening 5d. However, the present invention is not limited to this, and may be any shape as long as an appropriate gap is set with the shutter device.

1 Camera body
2 Lens mount
3 Release button
4 Image sensor
4a Low-pass filter
4b Infrared cut filter
5 Shutter device
5a Shutter blade
5b Subject-side shutter member
5b-1 Subject side shutter member opening edge
5b-2 Subject-side shutter member opening edge
5c Shadower side shutter member
5d exposure aperture
5e Drive lever
50 Luminous flux
100 mirror box
101 Main mirror
102 Submirror
106 Focus plate
107 Focus detection unit
107a condenser lens
107b Aperture
107c Secondary imaging lens
107d Focus detection sensor
108 Optical member holding member
109 pentamirror
110 Sub mirror biasing spring
111 Main mirror holding member
111a Anti-reflective sheet
112 Sub mirror holding member
112a Sub mirror holding member contact surface
112f Anti-reflective sheet
112g Submirror holding member first shutter facing surface
112h Sub mirror holding member second shutter facing surface
112i Sub mirror holding member Third shutter facing surface

Claims (4)

A first reflecting member (101) for separating the photographing light beam 50 incident from the photographing optical system into reflected light to the finder unit (106, 109) and transmitted light to the focus detection device;
A second reflecting member (102) for reflecting the transmitted light from the first reflecting member to the focus detection device (107);
A shutter device (5) for controlling subject light incidence on the image sensor (4),
The first holding member (111) that holds the first reflecting member (101) rotatably holds the second holding member (112) that holds the second reflecting member (102), and retracts during exposure. In an imaging device configured to be movable to a position,
The second holding member (112) is configured with a larger area than the exposure opening so as to cover at least the region below the imaging device with respect to the optical axis center of the exposure opening (5d) of the shutter device (5). An imaging apparatus characterized by comprising: The photographer's side surface of the second holding member (112) is composed of a surface (112h, 112i) different from the region other than the exposure opening region (112g) and the exposure opening region of the shutter device (5). 2. The imaging device according to claim 1, wherein: The region (112h, 112i) other than the exposure opening portion of the shutter device (5) of the second holding member (112) is provided closer to the subject side than the exposure opening region (112g). The imaging device according to claim 1 or 2. A surface parallel to the shutter device is provided on the lower tip (112h) of the imaging device in a region other than the opening for exposure of the shutter device (5) of the second holding member (112), and a tip in the left-right direction (112i 4. The image pickup apparatus according to claim 3, wherein a chamfered shape is provided on.