JP2008177845A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera capable of removing dust effectively over the entire surface of an optical member while restraining the upsizing of the camera. <P>SOLUTION: An optical low-pass filter 5 arranged in front of an image pickup device 4 prevents dust entering through an interchangeable lens mount portion from moving in the direction of the image pickup device for adhering onto an image pickup surface. The longitudinal direction of a piezoelectric actuator 6 is allowed to coincide with the direction of an optical axis for arranging at a vacant space where an interface is arranged, and the entire optical low-pass filter 5 reciprocates in a direction orthogonally crossing the optical axis by the bending deformation of the piezoelectric actuator 6, thus restraining the upsizing of the camera, and removing the dust effectively over the entire surface of the optical low-pass filter 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a camera using an image sensor such as a CCD.

  A digital camera is a type of camera that captures a subject image into an image sensor, and in recent years, single-lens reflex digital cameras have rapidly spread. In the case of a digital camera, if a foreign substance such as dust or dust adheres to the cover glass of the image sensor or the surface of the low-pass filter arranged in front of the image sensor, it is imprinted in the image and a good image cannot be obtained. . In particular, in the case of a single-lens reflex camera, there is a problem because dust or the like that floats in the air when the lens is replaced easily enters the camera body. Therefore, a standing wave vibration is generated in the dustproof filter itself arranged in the vicinity of the imaging surface of the imaging element, that is, the dustproof filter is bent by the standing wave vibration to remove the attached dust (for example, Patent Document 1).

Japanese Patent No. 3727903

  However, the above-described conventional technique for generating standing wave vibration in the dustproof filter itself has a drawback that the filter does not vibrate (vibration node) and it is difficult to remove dust adhering to the vicinity.

A camera according to a first aspect of the present invention is provided in an image sensor that captures a subject image, an optical member that is disposed on the optical axis and prevents dust from adhering to the image sensor, and a side region in the camera body. And a plurality of interface portions to which connection lines to an external device are connected, and a bending deformation type actuator disposed in a side surface region and reciprocatingly moving the entire optical member by bending deformation.
According to a second aspect of the present invention, in the camera according to the first aspect, a plate-like bending deformation type actuator that bends and deforms is disposed so that the longitudinal direction thereof substantially coincides with the optical axis direction, and the bending deformation type actuator is bent. The optical member is reciprocated in a direction orthogonal to the optical axis by deformation.
According to a third aspect of the present invention, in the camera according to the first aspect, the camera includes an elastic member that elastically supports the optical member. It is intended to be struck in the axial direction.

  According to the present invention, it is possible to effectively remove dust over the entire surface of the optical member while suppressing an increase in size of the camera.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a camera according to the present invention. FIG. 1 shows a schematic configuration of an interchangeable lens digital still camera. FIG. 1 (a) is a view of the camera taken in a horizontal section, and FIG. 1 (b) is a view of the inside of the camera body 1 viewed from the side of the camera. .

  The camera body 1 is detachably provided with a lens barrel 2 having a plurality of lenses. A mirror 9 is detachably provided on the optical axis in the camera body 1, and when the mirror 9 is disposed on the optical axis as shown in FIG. 1B (non-exposure state), The subject light that has passed through the lens barrel 2 is reflected by a mirror 9 to a finder optical system (not shown). On the other hand, at the time of exposure, the mirror 9 is moved away from the optical axis, and the shutter unit 8 is opened and closed. As a result, the subject image formed by the lens barrel 2 is picked up by the image pickup device 4.

  The image pickup device 4 is constituted by a solid-state image pickup device such as a CCD or a CMOS, and is provided on the image pickup device installation plate 3. An optical low-pass filter 5 held by a filter frame 10 is disposed in front of the imaging surface of the imaging element 4. The filter frame 10 is fixed on an elastic member 11 provided on the imaging element installation plate 3. The elastic member 11 is made of rubber or urethane material.

  As described above, since the optical low-pass filter 5 is provided in front of the image pickup element 4, dust entering from the mount portion where the lens barrel 2 is attached and detached moves in the direction of the image pickup element and adheres to the image pickup surface. Can be prevented. In addition, since the elastic member 11 is provided so as to surround the periphery of the image sensor 4 and the image sensor 4 is disposed in a sealed space, dust enters the gap between the optical low-pass filter 5 and the image sensor 4. There is no.

  One end of the bimorph piezoelectric actuator 6 is fixed to the lower end of the filter frame 10 in the figure. The other end of the piezoelectric actuator 6 is fixed to the column 13 with a screw 100. The support column 13 is fixed on the power supply board 12 of the camera, and the power supply board 12 is provided with a drive circuit (not shown) for driving and controlling the piezoelectric actuator 6.

  On the other hand, the upper end portion of the filter frame 10 in the drawing is placed on the end portion 3a of the image pickup device installation plate 3 bent in a step shape. FIG. 2 is a view of the image pickup device installation plate 3 provided with the image pickup device 4 and the optical low-pass filter 5 as viewed from the shutter 8 side. A pin 200 is attached to the end 3 a, and the pin 200 passes through a long hole 10 a formed in the filter frame 10. Therefore, the filter frame 10 can move in the left-right direction of the camera (left-right direction in FIG. 2).

  Returning to FIG. 1, a battery 17 is provided in the upper grip portion of the camera body 1 in the figure. On the other hand, interfaces 18 and 19 to which external devices such as a USB terminal and a Vout terminal are connected are arranged in a space where the side surface of the camera body 1 is (the lower side in the drawing). The interfaces 18 and 19 are attached to the interface board 14. In the same space, interfaces 15 and 20 such as DC input terminals provided on the power supply board 12 are also arranged. Further, a flash lighting capacitor 16 is provided in a space on the left side of the interface board 14 in the figure.

  That is, a space for arranging various interfaces and the like is secured on the side of the imaging-related components such as the image sensor 4 arranged along the optical axis, and these are arranged in the camera depth direction. In the present embodiment, the longitudinal direction of the plate-like piezoelectric actuator 6 is arranged in the optical axis direction in this space where the interface is arranged and has a margin in the depth direction.

  FIG. 3 is a diagram for explaining the operation of the bimorph piezoelectric actuator 6. FIG. 3A shows a case where the applied voltage of the piezoelectric actuator 6 is off, and FIG. 3B shows a case where the applied voltage is on. The bimorph piezoelectric actuator 6 has a structure in which two piezoelectric bodies 61 and 62 are bonded via an electrode 63, and an electrode 64 is provided on the other surface of the piezoelectric body 61. An electrode 65 is provided on this surface. As the piezoelectric bodies 61 and 62, for example, piezoelectric ceramic (for example, PZT-based) thin plates are used. The electrode 63 is connected to the switch 72, and the electrodes 64 and 65 are connected to the positive side of the power supply 71 provided in the drive circuit 7.

  The polarization directions of the piezoelectric bodies 61 and 62 are the thickness direction of the thin plate and are the same direction. When the switch 72 is closed as shown in FIG. 3B, the electrode 63 is connected to the negative side of the power source 71 via the switch 72. As a result, an electric field is formed from the electrode 64 to the electrode 63 in the piezoelectric body 61, and an electric field is formed from the electrode 65 to the electrode 63 in the piezoelectric body 62. At this time, due to the piezoelectric inverse effect, the piezoelectric body 61 in which the direction of the electric field and the polarization direction coincide with each other extends in the lateral direction (shrinks in the thickness direction), and the piezoelectric body 62 in which the direction of the electric field and the polarization direction reverse to each other. Shrink in the direction (extend in the thickness direction).

  As a result, the piezoelectric actuator 6 bends and deforms downward in the drawing as shown in FIG. Further, when the electrode 63 is positive and the electrodes 61 and 62 are negative, the piezoelectric actuator 6 bends and deforms upward in the figure, contrary to the bending direction shown in FIG. In order to repeatedly bend and deform the piezoelectric actuator 6, the switch 72 may be repeatedly turned on and off, or an AC voltage may be applied from an AC power source. In the present embodiment, a case where an AC power supply is provided as the power supply 71 and an AC voltage is applied to both the left and right piezoelectric actuators 6 will be considered.

  As shown in FIG. 1A and FIG. 2, the filter frame 10 reciprocates in the direction orthogonal to the optical axis by bending and deforming the piezoelectric actuator 6 in the direction orthogonal to the optical axis. And when the optical low-pass filter 5 vibrates, the dust adhering to the surface of the optical low-pass filter 5 falls off. Here, the pin 200 penetrating the long hole 10a regulates the size (amplitude) that the filter frame 10 can reciprocate. When the piezoelectric actuator 6 tries to reciprocate the filter frame 10 greatly, the long hole 10a Side wall collides with the pin 200. The dust attached to the surface of the optical low-pass filter 5 is more effectively removed by the impact of the collision.

  In the present embodiment, the entire optical low-pass filter 5 is reciprocated in the direction orthogonal to the optical axis by the piezoelectric actuator 6 that bends and deforms. not exist. As a result, effective dust removal can be performed over the entire surface of the optical low-pass filter 5. Further, as shown in FIG. 1, since the longitudinal direction of the plate-like piezoelectric actuator 6 coincides with the optical axis direction and is arranged in an empty space in which the interface is arranged, the space is efficient and the camera is enlarged. Can be prevented.

  Further, since the piezoelectric actuator 6 has a fast reaction speed, it is possible to remove dust in a short time from immediately after the mirror up to the start of photographing. Therefore, dust can be removed immediately before shooting, and shooting without the influence of dust can always be performed.

  In the present embodiment, since the optical low-pass filter 5 functions as an optical member that prevents dust from adhering to the imaging surface, the optical low-pass filter 5 is vibrated. However, in the case where the image pickup element and the optical low-pass filter constitute one unit and the cover glass provided in the unit prevents dust from adhering to the image pickup surface, the cover glass is similarly vibrated. Anyway.

[Modification]
4 and 5 are diagrams showing a first modification of the present embodiment, and are the same as FIGS. In the above-described embodiment, the longitudinal direction of the piezoelectric actuator 6 is made coincident with the optical axis direction, and is bent and deformed in a direction orthogonal to the optical axis. However, in the modified example, the longitudinal direction of the piezoelectric actuator 6 is orthogonal to the optical axis. The piezoelectric actuator 6 is bent and deformed in the optical axis direction in accordance with the direction.

  The tip of the piezoelectric actuator 6 is not fixed to the filter frame 10 but is merely in contact therewith, and the piezoelectric actuator 6 is bent and vibrated in the optical axis direction so that the filter frame 10 is hit with the tip of the piezoelectric actuator 6. . The pins 200 prevent the filter frame 10 from shifting in a direction perpendicular to the optical axis, and the filter frame 10 is movable in the optical axis direction. In addition, a gap is provided between the filter frame 10 and the image sensor mounting plate 3. Therefore, when one end of the filter frame 10 provided on the elastic member 11 is hit with the piezoelectric actuator 6, the entire filter frame 10 reciprocates in the optical axis direction.

  Dust adhering to the surface of the optical low-pass filter 5 falls off the surface due to an impact when the piezoelectric actuator 6 strikes the filter frame 10. Therefore, also in the modified example, the entire optical low-pass filter 5 vibrates, and there is no point (vibration node) that does not vibrate as in the prior art, so that effective dust removal can be performed over the entire surface of the optical low-pass filter 5. Also in the modified example, since the piezoelectric actuator 6 is arranged in an empty space in which the interface is arranged, the space efficiency is good and the enlargement of the camera can be prevented.

  In the correspondence between the embodiment described above and the elements of the claims, the optical low-pass filter 5 constitutes an optical member, and the interfaces 15 and 18 to 20 constitute an interface part. In the above-described embodiment, a bimorph type piezoelectric actuator is used as the piezoelectric actuator 6, but a monomorph, unimorph, or multimorph piezoelectric actuator may be used as long as it is an actuator that bends and deforms. Further, the above description is merely an example, and when interpreting the invention, there is no limitation or restriction on the correspondence between the items described in the embodiment and the items described in the claims.

It is a figure which shows schematic structure of a digital still camera of an interchangeable lens type, (a) is the figure which cut | disconnected the camera horizontally, (b) is the figure which looked at the inside of the camera body 1 from the camera side. It is the figure which looked at the image pick-up element installation board 3 provided with the image pick-up element 4 and the optical low-pass filter 5 from the shutter 8 side. It is a figure explaining operation | movement of the bimorph type | mold piezoelectric actuator 6, (a) shows the case where an applied voltage is OFF, (b) shows the case where an applied voltage is ON. It is a figure which shows a modification, (a) is the figure which cut | disconnected the camera horizontally, (b) is the figure which looked at the inside of the camera body 1 from the camera side. It is the figure which looked at the image sensor installation board 3 in the modification from the shutter 8 side.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1: Camera body, 2: Interchangeable lens, 3: Image pick-up element installation board, 4: Image pick-up element, 5: Optical low-pass filter, 6: Piezoelectric actuator, 10: Filter frame, 11: Elastic member, 15, 18-20: Interface 61, 62: Piezoelectric material, 63, 63, 65: Electrode, 71: Power supply, 72: Switch, 200: Pin

Claims (3)

An image sensor for capturing a subject image;
An optical member disposed on the optical axis and preventing dust from adhering to the image sensor;
A plurality of interface units provided in a side region in the camera body and connected to a connection line with an external device;
A camera comprising: a bending deformation type actuator disposed in the side surface region and reciprocatingly moving the entire optical member by bending deformation. The camera of claim 1,
The plate-shaped bending deformation type actuator that bends and deforms is arranged so that its longitudinal direction substantially coincides with the optical axis direction, and the optical member reciprocates in a direction perpendicular to the optical axis by bending deformation of the bending deformation type actuator. A camera characterized by being moved. The camera of claim 1,
An elastic member that elastically supports the optical member;
The camera according to claim 1, wherein the bending deformation type actuator bends and deforms in the optical axis direction and strikes the elastically supported optical member in the optical axis direction.

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