JP4935389B2 - Digital camera - Google Patents

Description

The present invention also relates to a digital camera.

  There is a camera that provides illumination means such as an LED below the mirror box, illuminates the imaging unit through an opening provided on the lower surface of the mirror box, and detects dust (foreign matter) adhering to the optical filter (for example, see Patent Document 1). .

JP 2002-300442 A

  The structure of Patent Document 1 described above only detects dust attached to the imaging unit, and cannot remove the attached dust.

A digital camera according to the present invention includes a mirror unit that is inserted in an optical path from a photographing lens to an imaging unit, and that can be rotated between an observation position that reflects a light beam from the photographing lens and a photographing position that is retracted from the optical path, and a mirror It has a mirror box which arranges a unit inside so that rotation is possible, and has an opening which discharges air which moves by rotation of a mirror unit from a mirror box.
A digital camera according to another aspect of the invention is a mirror box that forms a space for guiding the light flux from the photographic lens to the imaging unit, and is disposed inside the mirror box, and is inserted into the photographic optical path from the photographic lens to the imaging unit. A mirror unit that can rotate between an observation position that reflects light and a photographing position that is retracted from the photographing optical path, and a mirror box that includes a portion closer to the photographing lens than the photographing lens side end of the mirror unit at the observation position And an opening that is formed in the region and discharges air that is moved by the rotation of the mirror unit from the mirror box.
A digital camera according to another aspect of the invention is a mirror box that forms a space for guiding the light flux from the photographic lens to the imaging unit, and is disposed inside the mirror box, and is inserted into the photographic optical path from the photographic lens to the imaging unit. A mirror unit that can be rotated between an observation position that reflects light and a photographing position that is retracted from the photographing optical path, a light control unit that is disposed near the mirror box, and a mirror box that is closer to the photographing lens than the light control unit. And an opening for discharging air that is moved by rotation of the mirror unit.
A digital camera according to another aspect of the invention is a mirror box that forms a space for guiding the light beam from the photographic lens to the imaging unit, and is arranged inside the mirror box, and is inserted into the photographic optical path from the photographic lens to the imaging unit to The mirror unit is formed in the region of the mirror unit that can be rotated between the reflecting observation position and the photographing position retracted from the photographing optical path, and the mirror unit in the direction in which the mirror unit moves from the photographing position to the observation position. And an opening for discharging the moving air .

  According to the present invention, it is possible to effectively prevent dust from adhering to the imaging unit.

An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a front view of a single-lens reflex digital camera according to the present embodiment, and FIG. 2 is a cross-sectional view taken along the line AA. The camera body 100 is provided with a mirror box 20 that forms a photographing optical path behind the lens mount 11, a shutter 12 is arranged behind the mirror box 20, and an imaging unit 13 is arranged behind the shutter 12. A finder optical system 60 is disposed above the mirror box 20.

  An interchangeable lens (photographing lens) 200 is attached to the lens mount 11, and the subject light flux that has passed through the interchangeable lens 200 enters the mirror box 20 from the opening of the lens mount 11. A mirror unit 30 is disposed in the mirror box 20.

FIG. 15 is a block diagram showing a schematic configuration of the digital camera of the present embodiment.
As will be described later, the subject luminous flux input through the photographing lens 200 is reflected by the mirror unit 30 when entering the viewfinder optical system when the mirror unit 30 is at the observation position, and enters the imaging unit 13 when it is at the photographing position. Incident and imaged. The image signal output from the imaging unit 13 is temporarily stored in a buffer memory (not shown), and known image processing such as white balance processing, color conversion processing, and gradation correction processing is performed by the control circuit 71. The image data processed in the control circuit 71 is compressed by a known method such as the JPEG method, and is recorded in a memory card 73 that is detachable from the camera body and inserted in the memory card slot 72. The recording destination of the image data may be a memory card 73 that can be attached to and detached from the camera body, or a memory 79 that is built in the camera body.

  The operation unit 74 is various operation members for operating the digital camera. A release button and an operation member for instructing a dust removal operation described later are included. The lid 41 is a lid for opening and closing an air hole, which will be described later, and the opening and closing is controlled from the control circuit 71 via the opening and closing mechanism 75. The opening / closing of the lid 41 is not only controlled by the control circuit 71, but may be opened / closed only by a mechanical mechanism in accordance with the mounting of the photographing lens 200.

  The taking lens detection unit 76 detects the attachment / detachment of the taking lens 200 from the camera body. A signal for attaching and detaching the photographic lens 200 detected by the photographic lens detection unit 76 may be sent to the control circuit 71 and a dust removal operation may be performed in accordance with the detachment of the photographic lens 200. Further, a signal regarding power on / off may be sent from the power supply unit 77 to the control circuit 71, and a dust removal operation may be performed in accordance with power on / off. The mirror unit 30 is controlled by the control circuit 71 via the mirror drive circuit 78, and is driven not only when shooting, but also when performing dust removal operations. The dust removal operation will be described in detail later.

  3 and 4 are enlarged views of the vicinity of the mirror box, and FIG. 5 is a schematic view of the mirror box 20 as viewed from above (finder side). The mirror unit 30 includes a main mirror unit 31 including a main mirror (half mirror) and a support member thereof, and a sub mirror unit 32 including a sub mirror and a support member thereof.

  One end of the main mirror unit 31 is supported at the rear of the mirror box so as to be rotatable about the camera horizontal axis X, and the sub mirror unit 32 is rotatable about the camera horizontal axis with respect to the main mirror unit 31. Supported by The mirror unit 30 is driven by the control circuit 71 via the mirror drive circuit 78, and is between the observation position inserted into the imaging optical path as shown in FIG. 3 and the imaging position retracted from the imaging optical path as shown in FIG. Can be rotated. FIG. 6 shows a state during mirror rotation.

  A dimming unit 80 (FIG. 7) is provided in the lower space 50 of the mirror box 20, and a focus detection unit is disposed behind the dimming unit 80, and a lens driving mechanism (both not shown) is disposed in front thereof. The dimming unit 80 includes an element that receives and reflects photoelectrically reflected light from the screen of the shutter 12, and the photoelectric conversion output is used for dimming.

  The bottom plate 21 of the mirror box 20 is provided with a slit-like air hole 21 a that connects the inner space of the mirror box and the lower space 50. Although the action of the air hole 21a will be described later, the air hole 21a is provided on the lens side of the light control unit 80, preferably on the lens side of the end of the mirror unit 30 at the observation position. The width of the air hole 21a in the front-rear direction of the camera is about 1 to 2 mm in this embodiment, but may be narrower or wider than this.

  The air hole 21 a can be opened and closed by a lid member 41. The lid member 41 is supported by a substrate 42, and the substrate 42 is supported so as to be able to advance and retract in the front-rear direction (the optical axis direction of the photographing lens). Reference numeral 43 denotes a tension spring that biases the substrate 42 toward the lens side. A pin projecting from the camera body is engaged with the long hole formed in the substrate 42, whereby the advance / retreat of the substrate 42 is guided. The protrusion 42a formed on the substrate 42 penetrates the camera body 100 and is pushed by the rear wall surface 201 of the interchangeable lens 200 as shown in FIG. In this state, the lid member 41 is retracted to the rear of the air hole 21a, and the air hole 21a is open.

On the other hand, when the interchangeable lens 200 is removed from the mount 11 as shown in FIG. 4, the pressing of the protrusion 42 a is released, so that the substrate 42 moves to the mount 11 side by the urging force of the spring 43 and interlocks with this. The air hole 21 a is closed by the lid member 41.
6 and 7, the lid member 41 and its drive mechanism (42, 43) are not shown. Further, the air hole 21a is opened by the cover member 41 being retracted and opened by the opening / closing mechanism 75 (FIG. 15) controlled by the control circuit 71 while the mirror unit 30 is rotating. If not, the lid member 41 may be closed. The air hole 21a is opened by retracting the lid member 41 by an opening / closing mechanism 75 (FIG. 3) controlled by the control circuit 71 when the digital camera is turned on, and is closed by the lid member 41 when the power is turned off. It doesn't matter if you do.

  The imaging unit 13 is a set in which an imaging element 13a such as a CCD and an optical filter (such as an optical low-pass filter or an infrared cut filter) 13b disposed in front of the CCD are integrated. The light beam that has passed through the opening of the shutter 12 passes through the optical filter 13b and is received by the image sensor 13a, and image data is generated and recorded from the photoelectric conversion output of the image sensor 13a.

  In the camera configured as described above, when not photographing, the mirror unit 30 is in the observation position shown in FIG. For this reason, a part of the subject luminous flux incident in the mirror box 20 is reflected upward by the main mirror unit 31 and enters the finder optical system 60, and is observed through the eyepiece 61 (FIG. 2). Further, a part of the light beam transmitted through the main mirror unit 31 is reflected downward by the sub mirror unit 32 and is incident on a focus detection unit (not shown) provided in the lower space 50 to contribute to focus detection.

  When the release button 1 (FIG. 1) is fully pressed, the control circuit 71 jumps the mirror unit 30 up to the photographing position in FIG. 7 via the mirror driving circuit 75 and retracts it from the photographing optical path. Next, the shutter 12 is opened, and the subject luminous flux incident in the mirror box 20 passes through the shutter opening without being blocked by the mirror unit 30 and is guided to the imaging unit 13.

  By the way, when the taking lens 200 or the cap is not attached to the lens mount 11, the mirror box 20 communicates with the external space through the lens mount 11, so that fine dust floating in the atmosphere is transferred from the lens mount 11 to the mirror box. 20 may enter. Further, dust generated in the camera due to driving of the shutter 12 or the like is also floating in the mirror box 20. If such dust adheres to the imaging unit 13, particularly the front surface of the optical filter 13b, this may be reflected in the captured image and reduce the appearance of the image.

A mechanism by which dust adheres to the optical filter 13a will be described.
8 to 10 show a conventional camera in which no air hole 21a is provided. When the mirror unit 30 is at the observation position as shown in FIG. It is closed pneumatically (not completely sealed). When the release button is operated and the mirror unit 30 is flipped up as shown in FIG. 9, the upper space of the mirror unit 30 is rapidly narrowed. Therefore, most of the air in the upper space is in front of the mirror unit 30, that is, the mirror. The space between the unit 30 and the interchangeable lens 200 descends with a relatively rapid flow (arrow C). At this time, dust in the air also moves in the same direction along the air flow.

  The lowered air collides with the bottom plate 21 of the mirror box 20 and changes its direction, causing an air flow toward the shutter 12 (arrow D). After that, as shown in FIG. 10, when the mirror unit 30 reaches the photographing position and the shutter 12 is opened, the air directed toward the shutter 12 side passes through the shutter opening (slit opening) S and reaches the imaging unit 13 to become air. The carried dust adheres to the front surface of the optical filter 13b.

Next, the dustproof action by the air holes 21a will be described.
In the present embodiment, an air hole 21a is provided in front of the mirror unit 30 (lens side) in the mirror box bottom plate 21, and the air hole 21a is opened when the lens is mounted. As shown in FIG. 6, the position of the air hole 21a is almost directly below the flow of air that is lowered by the mirror unit 30 jumping up, so that most of the lowered air travels straight through the air hole 21a. (Arrow F) and discharged into the lower space 50. As a result, a large amount of dust that has entered the air is also discharged into the lower space 50. Therefore, air (dust) heading in the D direction on the mirror box bottom plate 21 is greatly reduced compared to the conventional case, and the amount of dust attached to the optical filter 13b after running the shutter is reduced as shown in FIG.

As the position where the air hole 21a is formed, dust can be exhausted out of the mirror box 20 using the air flow generated by the mirror unit 30, and the air flow toward the direction D in FIG. The following positions can be considered.
The air holes 21a are formed only in a region of the bottom plate 21 of the mirror box 20 that is closer to the lens side than the lens side end of the mirror unit 30. Further, at least a part of the air holes 21 a may be formed so as to be arranged in the region of the lens portion rather than the lens side end portion of the mirror unit 30. Moreover, you may provide in the area | region of the rotation direction (The direction of C of FIG. 9, or its reverse direction) of the mirror unit 30 of the bottom plate 21 or upper plate of the mirror box 20. FIG. Further, the position of the bottom plate 21 in the direction perpendicular to the optical axis of the lens (position in the vertical direction in FIG. 5) is preferably the central portion close to the optical axis of the lens, and the vertical direction (vertical direction in FIG. 5). Is preferably equal to or smaller than the width of the mirror unit 30, but may be larger than the width of the mirror unit 30. Further, the air hole 21a may be provided in a region of the mirror box 20 closer to the photographing lens than the intersection of the mirror unit 30 at the observation position and the optical axis of the photographing lens.

  Thus, in this embodiment, the amount of dust attached to the imaging unit 13 can be reduced by a simple process of opening an air hole in a part of the mirror box 20 without adding any members. According to the experiments by the present inventors, when the dust condition of the optical filter 13b is compared between the structure of this embodiment and the conventional structure (FIGS. 8 to 10), the camera body 100 performs the photographing operation 10,000 times. In this embodiment, it was confirmed that the amount of adhered dust after the reduction can be reduced to nearly half of that in the prior art.

  By the way, when the interchangeable lens 200 is removed from the lens mount 11, the portion where the air hole 21 a is formed is exposed to the outside. At this time, the air hole 21 a is closed by the lid member 41, so the member disposed in the lower space 50. Is not visually recognized, and the appearance is not impaired.

The dust discharging operation associated with the mirror driving at the time of shooting has been described above, but the dust discharging operation at the time of shooting will be described.
For example, when changing the lens, there is a possibility that external dust may enter the mirror box 20. After the lens replacement, the control circuit 71 detects that the interchangeable lens 200 has been attached, jumps the mirror unit 30 from the observation position to the photographing position, and then returns to the observation position. This mirror drive is performed with the shutter 12 closed. Thereby, much of the dust that has entered the mirror box 20 can be discharged from the air hole 21a to the lower space 50. Thereafter, dust is also discharged by driving the mirror at the time of photographing, so that the amount of dust attached to the optical filter 13b can be further reduced.

  In addition to when the lens is mounted, for example, the mirror may be driven in the same manner as when the lens is replaced to discharge dust when the camera is turned on or off. Alternatively, mirror driving may be performed in the same manner for dust discharge in accordance with an operator's specific operation (dust discharge operation). In any case, it is desirable that the mirror drive is permitted only when the intrusion of dust from the outside is blocked, that is, when the interchangeable lens 200 or the cap is attached to the lens mount 11. Further, the mirror drive other than the above-described shooting is effective even once, but more dust can be discharged by repeating a plurality of times.

  Further, mirror driving may be performed for the purpose of removing dust adhering to the optical filter 13b. This mirror drive for dust removal is performed with the shutter 11 open. Contrary to the above, when the mirror unit 30 is lowered from the photographing position to the observation position, the air below the mirror unit 30 hits the front surface of the optical filter 13b through the shutter opening and plays a role of removing dust. Since the mirror unit 30 is lowered, the lower space of the mirror unit 30 is abruptly narrowed. Therefore, most of the air in the lower space flows forward in the space below the mirror unit 30 and moves to the space in front of the mirror unit. By this flow, dust is carried to the space in front of the mirror unit, and is discharged from the air hole 21a to the lower space 50 by the operation of the mirror unit from the next time.

  Alternatively, the mirror unit 30 may be rotated from the photographing position to the observation position with the shutter 11 opened, and the mirror unit 30 may be rotated from the observation position to the photographing position with the shutter 11 closed. When the mirror unit 30 rotates from the photographing position to the observation position, since the shutter 11 is open, the air below the mirror unit 30 passes through the shutter opening and hits the front surface of the optical filter 13b to remove dust. Drop it. Next, when the mirror unit 30 rotates from the observation position to the photographing position, the shutter 11 is in a closed state, and dust in the mirror box 20 is discharged from the air hole 21a. By performing this operation at least once, preferably a plurality of times, dust attached to the optical filter 13b can be removed. It is desirable that the mirror drive in this case is allowed only when the interchangeable lens 200 or the cap is attached to the lens mount 11. This operation may be performed when the power is turned on or off, or according to a specific operation of the operator. Further, it may be determined from the photographed image whether dust is attached to the optical filter 13b, and dust may be removed by driving a mirror. In this case, a white object may be photographed so that dust can be easily determined, and dust can be determined from the captured image. Further, it may be determined whether the dust is attached by the control unit, and the mirror is automatically driven to remove the dust.

  Also, in combination with the conventional method of vibrating the image pickup unit to remove dust, and performing the mirror drive for dust removal described above while vibrating the image pickup unit, the dust removal efficiency is improved by the synergistic effect of vibration and air flow. Up. The operation in this case will be described below.

  First, with the shutter opened, the optical filter 13b starts to vibrate in order to remove dust adhering to the optical filter 13b. Next, dust is discharged from the air holes 21c by driving a plurality of mirror units 30. When the driving of the mirror unit 30 is finished, the shutter 11 is closed and the vibration of the optical filter 13b is stopped. The attached dust is removed by vibrating the optical filter 13b, and the removed dust is discharged from the air hole 21c by driving the mirror unit 30. Further, the dust remaining on the surface of the optical filter 13b can be removed by driving the mirror unit 30. Although there is no particular limitation on the driving direction of the mirror unit 30, it is preferable to first place the mirror unit 30 at the photographing position and then drive to the observation position from there.

  Note that, with the shutter open, the optical filter 13b is driven to remove dust, and before the mirror unit 30 is driven, the shutter 11 may be closed to stop the vibration of the optical filter 13b. Further, the vibration of the optical filter 13b may be performed only at the beginning. It is desirable that these dust removal operations are permitted only when the interchangeable lens 200 or the cap is attached to the lens mount 11.

  Furthermore, for example, when dust detection is performed by a method described in Japanese Patent Laid-Open No. 2002-300442 (cited reference 1), it is determined whether dust removal is necessary based on the result, and it is determined that it is necessary You may make it perform the mirror drive for the said dust removal.

  The number and shape of the air holes are not limited. In the embodiment described above, the air hole 21a is provided in the lens side portion of the mirror unit 30 at the observation position, but the air hole 21b is extended further rearward as shown in FIG. 11, for example. May be provided. Further, as shown in FIG. 12, the air hole 21c may be extended to the lens side.

  Further, if the air holes satisfy the condition that the lens side portion further includes the lens side end portion of the mirror unit 30 at the observation position, a dust discharge effect can be expected even if it is provided on a surface other than the mirror box bottom plate 21. FIG. 13 shows an example in which air holes 22 a are provided in both side walls 22 of the mirror box in addition to the air holes 21 a of the mirror box bottom plate 21. It may be provided on the mirror box upper plate.

  Furthermore, instead of providing air holes in the mirror box 20, for example, as shown in FIG. 14, air holes 201a may be provided in the rear wall 201 (surface facing the mirror unit 30) of the interchangeable lens 200. In this case, the air (dust) in the mirror box 20 is discharged through the air hole 201a to the space in the interchangeable lens 200 by the mirror unit 30 being flipped up, and the same effect as described above can be obtained.

  Further, in the above-described embodiment, the example in which the mirror unit 30 rotates about the camera horizontal axis is shown. However, the present invention can be similarly applied to a camera in which the mirror unit rotates about the camera vertical axis. .

  The lid member 41 is not an essential requirement of the present invention.

The front view of the single-lens reflex digital camera in one Embodiment. AA sectional view taken on the line AA of FIG. FIG. 3 is an enlarged view of the vicinity of the mirror box in FIG. 2. The enlarged view of the mirror box vicinity which shows the state which removed the interchangeable lens. The schematic diagram which looked at the mirror box from the camera upper surface. The figure explaining the flow of air when a mirror unit is in the middle of a raise. The figure which shows the state which the mirror unit rose to the imaging position. It is a figure explaining the flow of air in the conventional camera, and shows a state where the mirror unit is at the observation position. FIG. 9 is a view similar to FIG. 8 and shows a state where the mirror unit is in the middle of ascending. FIG. 9 is a view similar to FIG. 8 and shows a state where the mirror unit is at the photographing position. The figure which shows the example which provided the large sized air hole. The figure which shows the example which provided the air hole in the corner | angular part of a mirror box bottom plate and a lens mount. The figure which shows the example which provided the air hole in the mirror box side wall. The figure which shows the example which provided the air hole in the interchangeable lens. The control block diagram of a camera.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Lens mount 12 Shutter 13 Imaging unit 20 Mirror box 21 Mirror box bottom plate 21a, 22a, 201a Air hole 22 Mirror box side wall 30 Mirror unit 41 Lid member 42 Substrate 43 Tension spring 50 Lower space 60 Finder optical system 71 Control circuit 80 Light control Unit 200 Interchangeable lens

Claims (20)

A mirror unit that is inserted in the optical path from the photographic lens to the imaging unit and is rotatable between an observation position that reflects a light beam from the photographic lens and a photographic position that is retracted from the optical path;
A mirror box that rotatably arranges the mirror unit;
A digital camera comprising: an opening through which air moving by the rotation of the mirror unit is discharged from the mirror box.   2. The digital camera according to claim 1, wherein the opening is formed in the mirror box closer to the photographing lens than an intersection of a mirror unit at the observation position and an optical axis of the photographing lens. .   The at least part of the opening is formed in a region closer to the photographing lens than the photographing lens side end of the mirror unit at the observation position of the mirror box. Digital camera. A mirror box that forms a space for guiding the light flux from the photographing lens to the imaging unit;
A mirror unit that is disposed inside the mirror box and is rotatable between an observation position that is inserted into a photographing optical path from the photographing lens to the imaging unit and reflects the light beam and a photographing position that is retracted from the photographing optical path. When,
An opening that is formed in a region of the mirror box including a portion closer to the photographing lens than the photographing lens side end of the mirror unit at the observation position, and discharges air that is moved by the rotation of the mirror unit from the mirror box. And a digital camera. A mirror box that forms a space for guiding the light flux from the photographing lens to the imaging unit;
A mirror unit that is disposed inside the mirror box and is rotatable between an observation position that is inserted into a photographing optical path from the photographing lens to the imaging unit and reflects the light beam and a photographing position that is retracted from the photographing optical path. When,
A light control unit disposed in the vicinity of the mirror box;
A digital camera having an opening formed in a region of the mirror box closer to the photographing lens than the light control unit and for discharging air that moves by the rotation of the mirror unit. A mirror box that forms a space for guiding the light flux from the photographing lens to the imaging unit;
A mirror unit that is disposed inside the mirror box and is rotatable between an observation position that is inserted into a photographing optical path from the photographing lens to the imaging unit and reflects the light beam and a photographing position that is retracted from the photographing optical path. When,
A digital camera having an opening formed in an area of the mirror box in a direction in which the mirror unit moves from an imaging position to an observation position, and discharges air that moves as the mirror unit rotates.   The digital camera according to claim 6, wherein the opening is formed in a region close to an optical axis of the photographing lens.   The opening is formed only in a portion closer to the photographing lens than an end portion on the photographing lens side of the mirror unit at the observation position of the mirror box. The digital camera according to item.   The said opening part is formed in the surface which does not cross | intersect neither the optical axis of the said taking lens of the said mirror box, or the rotation axis | shaft of the said mirror unit, The any one of Claims 1-8 characterized by the above-mentioned. The digital camera described.   The digital camera according to claim 1, wherein the opening is formed on a surface of the mirror box in the vicinity of the mirror unit at the shooting position.   9. The digital according to claim 1, wherein the opening is formed on a surface opposite to a surface in the vicinity of the mirror unit at the photographing position of the mirror box. camera.   The digital camera according to any one of claims 1 to 8, wherein the opening is formed on a surface of the mirror box that intersects with a rotation axis of the mirror unit. The digital camera according to claim 1, wherein the opening is provided on a bottom surface of the mirror box. 14. The shutter according to claim 1, further comprising: a shutter disposed between the mirror unit and the imaging unit, wherein the mirror unit rotates with the shutter closed. Digital camera. Having a shutter disposed between the mirror unit and the imaging unit;
The digital camera according to claim 1, wherein the mirror unit is rotated from the photographing position to the observation position in a state where the shutter is opened. Having a shutter disposed between the mirror unit and the imaging unit;
The mirror unit is rotated from the photographing position to the observation position with the shutter opened, and is rotated from the observation position to the photographing position with the shutter closed. Item 14. The digital camera according to any one of Items 1 to 13. The digital camera according to claim 1, further comprising a mounting portion on which a photographic lens can be mounted. The digital camera according to claim 1, wherein the opening has a slit shape. The digital camera according to claim 1, further comprising a vibration unit that vibrates the imaging unit. The digital camera according to claim 19, wherein the vibration unit vibrates the imaging unit when the mirror unit is rotating between the observation position and the photographing position.

Images