JP2008172585A - Dust-proof device, imaging device, camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively remove dust adhered to a dust-proof member. <P>SOLUTION: The dust-proof device is provided with the board-like dust-proof member 31 which prevents adhesion of the dust to an image pickup device 4 and a vibration generation means 32 for generating vibration in the dust-proof member, wherein the vibration generation means expands and contracts in the direction approximately perpendicular to the board surface of the dust-proof member, transmits its expanding and contracting movement to the dust-proof member, and the dust-proof member vibrates in the direction approximately perpendicular to its board surface according to the expanding and contracting movement transmitted from the vibration generation means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a dustproof device, an imaging device, and a camera for preventing dust from adhering to an imaging device.

  Conventionally, in a single-lens reflex digital camera with interchangeable lenses, by arranging a plate-like dustproof member between the image sensor and the photographing optical system, it is possible to prevent dust and dust from adhering to the image sensor, A device that removes dust and dirt adhering to the dust-proof member by vibrating the dust-proof member with a piezoelectric element is known (see Patent Document 1).

Japanese Patent Laying-Open No. 2005-20078

In the camera disclosed in Patent Document 1, by attaching a piezoelectric element to the dust-proof member, the piezoelectric element transmits the expansion and contraction motion generated in a direction parallel to the plate surface of the dust-proof member to the dust-proof member. It vibrates in the direction perpendicular to. Therefore, the expansion / contraction movement of the piezoelectric element cannot be efficiently transmitted to the dustproof member, and the dustproof member cannot be vibrated, and the dust attached to the dustproof member cannot be removed effectively.
An object of the present invention is to provide a dustproof device, an imaging device, and a camera that can effectively remove dust attached to a dustproof member.

A dustproof device according to a first aspect of the present invention includes a plate-like dustproof member that prevents dust from adhering to an image sensor, and vibration generating means that generates vibration in the dustproof member. In this dustproof device, the vibration generating means expands and contracts in a direction substantially perpendicular to the plate surface of the dustproof member, and transmits the expansion / contraction motion to the dustproof member. Further, the dustproof member vibrates in a direction substantially perpendicular to the plate surface in accordance with the expansion and contraction motion transmitted from the vibration generating means.
According to a second aspect of the present invention, in the dustproof device according to the first aspect, the dustproof device and the vibration generating means are further provided with pressing means for pressing the dustproof member and the vibration generating means in a direction in which the dustproof member and the vibration generating means approach each other.
According to a third aspect of the present invention, in the dustproof device according to the second aspect, the pressing means is screwed into a bolt that has a shaft portion passing through a through hole provided in the dustproof member and the vibration generating means, and a shaft portion of the bolt. The dust-proof member and the vibration generating means are screwed into the shaft portion of the bolt in a state where the dust-proof member and the vibration generating means are sandwiched between the bolt head and the nut. Press.
According to a fourth aspect of the present invention, in the dustproof device according to any one of the first to third aspects, the vibration generating means is configured by laminating a plurality of piezoelectric elements.
According to a fifth aspect of the present invention, there is provided an image pickup apparatus that outputs an image pickup signal of a subject based on an incident light beam, a dustproof member that prevents dust from adhering to the image pickup element, and a vibration generating means that generates vibration in the dustproof member. Are provided. In this imaging apparatus, the vibration generating means expands and contracts in a direction substantially perpendicular to the plate surface of the dustproof member, and transmits the expansion and contraction motion to the dustproof member. Further, the dustproof member vibrates in a direction substantially perpendicular to the plate surface in accordance with the expansion and contraction motion transmitted from the vibration generating means.
A camera according to a sixth aspect of the invention includes the imaging device according to the fifth aspect and a recording control unit that records a captured image of a subject on a recording medium based on an imaging signal.

  According to the present invention, dust adhering to the dustproof member can be effectively removed.

  FIG. 1 is a block diagram showing the configuration of a digital camera according to an embodiment of the present invention. This digital camera includes a camera body 100 and a photographic lens 200 attached to the camera body 100. The camera body 100 includes a CPU 1, an imaging device 2, a photometric device 5, a sequence device 6, a flash device 7, a power supply unit 8, a viewfinder display device 9, a display device 10, a controller 11, a memory card 12, an image processing unit 13, and a RAM 14. ROM 15 and operation member 16 are provided.

  The CPU 1 executes various processes and controls as described below in conjunction with other components. Various functions and operations are realized in the camera body 100 by the CPU 1 performing appropriate processing and control according to the operation state of the camera body 100.

  The imaging device 2 includes a dustproof device 3, a CCD 4, and a low bass filter (LPF) 41. The CCD 4 outputs an imaging signal based on the subject image formed by the light beam incident from the photographing lens 200. This imaging signal is converted into image data, and then output to the image processing unit 13 via the CPU 1. The LPF 41 is an optical member that removes a high frequency component from an incident light beam by being disposed in front of the CCD 4. The dustproof device 3 is disposed between the photographing lens 200 and the LPF 41 so as to substantially seal the CCD 4 and the LPF 41 in order to prevent dust and dirt from adhering to the CCD 4 and the LPF 41. Note that dust and dirt attached to the dustproof device 3 are removed by vibration generated in the dustproof device 3 as described later.

  The photometric device 5 measures the amount of incident light from the photographing lens 200, and obtains an appropriate exposure during photographing based on the measurement result. The appropriate exposure obtained by the photometric device 5 is output to the CPU 1 and used for controlling the sequence device 6 and the like. The sequence device 6 controls a series of mechanism operations at the time of shooting such as the operation of the quick return mirror and the operation of the shutter according to the control of the CPU 1. The flash device 7 is a flash device built in the camera body 100 and its operation is controlled by the CPU 1.

  The power supply unit 8 appropriately supplies necessary power to each part of the camera body 100 and the photographing lens 200. The in-finder display device 9 is provided in the finder of the camera body 100 and displays various information according to the operating state of the camera body 100. For example, information such as shutter speed, aperture value, and auto focus area is displayed on the in-finder display device 9. Thereby, it is possible to notify the user of information necessary for shooting.

  The display device 10 displays various images under the control of the CPU 1. For example, a captured image captured by the camera body 100, a setting menu screen including various setting menu items for performing various settings on the camera body 100, and the like are displayed. For example, a liquid crystal display or the like is used for the display device 10, and the display device 10 is installed at a position where the user can easily see the camera body 100.

  Under the control of the CPU 1, the controller 11 executes a writing process when recording captured image data on the memory card 12 and a reading process when reading captured image data recorded on the memory card 12. The memory card 12 is a general-purpose external recording medium that can be attached to and detached from the camera body 100, and image data captured by the camera body 100 is recorded by a writing process of the controller 11.

  The image processing unit 13 performs predetermined image processing on the captured image data output from the CCD 4. For example, the image processing unit 13 performs processing for adjusting the appearance of the captured image, processing for converting the format of the image data, and the like. The image data that has been subjected to image processing by the image processing unit 13 is recorded on the memory card 12 by the controller 11.

  The RAM 14 is used as a work area when the CPU 1 executes various processes and controls. The RAM 14 includes a VRAM used when displaying an image on the display device 10. The ROM 15 stores programs and data used when the CPU 1 executes various processes and controls. The operation member 16 includes various operation switches. Various processes and controls are executed in the CPU 1 in accordance with the operation content input by the user using the operation member 16.

  Next, details of the dustproof device 3 will be described with reference to the drawings. FIG. 2 is a plan view and a cross-sectional view of the imaging device 2 in which the dustproof device 3 is installed. In FIG. 2, a plan view of (a) shows a planar shape of the imaging device 2 when viewed from the direction of the taking lens 200 in the camera body 100. The cross-sectional view of (b) shows a cross section when the imaging device 2 is cut along line AA in the plan view of (a). The cross-sectional view of (c) shows a cross-section when the imaging device 2 is cut along line BB in the plan view of (a).

  In the imaging device 2 shown in FIG. 2, the dustproof device 3 includes a dustproof member 31, a vibration member 32, a washer 33, a bolt 34, a nut 35, a positioning pin 36, a leaf spring 37, and a support member 38. The CCD 4 is disposed on the substrate 42, and an LPF 41 is disposed on the upper side thereof, that is, in front of the imaging surface.

  The dust-proof member 31 having a plate shape is used to prevent dust and dirt from adhering to the CCD 4 and the LPF 41, and is disposed so as to cover the CCD 4 and the LPF 41. The dust-proof member 31 is provided on the optical path of subject light incident on the CCD 4 via the photographing lens 200, and is composed of a transparent material such as glass.

  The vibration member 32 is configured by stacking a plurality of piezoelectric elements that generate a piezoelectric effect. Between the layers of the stacked piezoelectric elements, electrodes for applying an electrical signal to the piezoelectric elements are provided. When an AC electric signal is applied to the vibration member 32 using this electrode, the vibration member 32 is substantially perpendicular to the optical axis direction of the lens 200 in FIG. 1, that is, the plate surface of the dust-proof member 31 in accordance with the AC electric signal. The expansion and contraction motion is periodically repeated in a certain direction (or a direction substantially perpendicular to the imaging surface of the CCD 4). The piezoelectric element is composed of piezoelectric ceramics or the like. As a material of this piezoelectric ceramic, for example, PZT (lead zirconate titanate) is known.

  The dustproof member 31 and the vibration member 32 are each provided with a through hole for allowing the shaft portion of the bolt 34 to pass therethrough. The shaft portion of the bolt 34 is passed through the through hole, and the nut 35 is screwed into the shaft portion of the bolt 34 with the dust-proof member 31 and the vibration member 32 sandwiched between the head portion of the bolt 34 and the nut 35. Then, the bolt 34 and the nut 35 are tightened. Thereby, the dustproof member 31 and the vibration member 32 are pressed toward the direction in which the dustproof member 31 and the vibration member 32 approach each other.

  In the state where the dust-proof member 31 and the vibration member 32 are pressed as described above, when the vibration member 32 contracts in the optical axis direction, the dust-proof member 31 is placed on the upper side of the image pickup device 2, that is, the CCD 4 by the pressure from the nut 35. Deformation in the direction opposite to the imaging surface. On the other hand, when the vibration member 32 extends in the optical axis direction, the dust-proof member 31 is moved toward the lower side of the image pickup device 2, that is, the image pickup surface of the CCD 4 due to the pressure from the vibration member 32 transmitted through the washer 33. Deform. In this way, the expansion and contraction motion of the vibration member 32 is transmitted to the dustproof member 31.

  The expansion and contraction motion transmitted from the vibration member 32 to the dust-proof member 31 is periodically repeated according to the AC electric signal applied to the vibration member 32. Therefore, the dustproof member 31 vibrates in a direction substantially perpendicular to the plate surface (that is, a direction substantially perpendicular to the optical axis direction of the lens 200 or the imaging surface of the CCD 4) by alternately repeating the above-described deformation. In this way, the dust-proof member 31 vibrates in accordance with the expansion and contraction motion transmitted from the vibration member 32, so that dust and dust attached to the dust-proof member 31 can be removed.

  The positioning pin 36 and the leaf spring 37 perform positioning when the dust-proof member 31 is provided in the imaging device 2. One positioning pin 36 is provided on each of the left and right sides of the dustproof member 31, and is in contact with the dustproof member 31 at the left and right ends of the dustproof member 31. Thereby, the position of the dustproof member 31 in the left-right direction is regulated. On the other hand, the leaf spring 37 is bent so as to contact the dustproof member 31 at the upper and lower ends of the dustproof member 31. Thereby, the position of the dustproof member 31 in the up-down direction is regulated. Thus, by restricting the positions of the dustproof member 31 in the left and right and up and down directions, the position of the dustproof member 31 is determined.

  Further, the leaf spring 37 has a function of biasing the dustproof member 31 so as to press it from above. That is, the leaf spring 37 is in contact with the plate surface of the dust-proof member 31 in the vicinity of the left and right outer edge portions of the dust-proof member 31, thereby applying pressure generated from the bent shape of the plate spring 37 to the contact surface. By this pressure, the dustproof member 31 is urged toward the lower side of the imaging device 2, that is, toward the imaging surface of the CCD 4.

  The support member 38 is disposed between the dust-proof member 31 and the LPF 41 along the vicinity of the outer edge portion of the dust-proof member 31. The dust-proof member 31 is supported by the support member 38. The support point for supporting the dust-proof member 31 by the support member 38 is preferably in the vicinity of the vibration node so as not to inhibit the vibration generated in the dust-proof member 31.

  When the dust-proof member 31 is biased by the leaf spring 37 as described above, the dust-proof member 31 is brought into close contact with the support member 38. Thus, a space for substantially sealing the CCD 4 and the LPF 41 is formed between the substrate 42 and the dust-proof device 3 using the dust-proof member 31 and the support member 38. In the plan view of FIG. 2A, the portion of the support member 38 that is shaded by the leaf spring 37 is not shown in the drawing, but actually, the support member along the four sides of the dust-proof member 31. 38 is disposed.

  FIG. 3 is a plan view and a cross-sectional view of the imaging device 2 when the leaf spring 37 is removed from each of the configurations described above. 3 also shows a plan view of the imaging device 2 when viewed from the direction of the photographing lens 200 in the camera body 100, as in FIG. The cross-sectional view of (b) shows a cross section when the imaging device 2 is cut along line CC in the plan view of (a). The cross-sectional view of (c) shows a cross-section when the imaging device 2 is cut along line DD in the plan view of (a).

  From the plan view of FIG. 3A, it can be seen that the support member 38 is disposed along the four sides of the dust-proof member 31 as described above. Reference numerals 37a, 37b, 37c and 37d are screw holes used when the leaf spring 37 is screwed and attached.

  FIG. 4 is a plan view and a cross-sectional view of the dustproof member 31, the vibration member 32, the washer 33, the bolt 34, and the nut 35. In FIG. 4, a plan view of (a) shows a planar shape when the above-described components are combined. The cross-sectional view of (b) shows a cross-section of each component when cut along line EE in the plan view of (a). The cross-sectional view of (c) shows a cross-section of each component when cut along line FF in the plan view of (a).

  From the cross-sectional view of FIG. 4C, it can be seen that the dustproof member 31 and the vibration member 32 are provided with through holes, and the shaft portion of the bolt 34 passes through the through holes. Further, when the nut 35 is screwed onto the shaft portion of the bolt 34, the dust-proof member 31 and the vibration member 32 sandwiched between the head portion of the bolt 34 and the nut 35 are pressed toward each other. You can see that.

  The dustproof member 31 has a specific resonance frequency corresponding to the material, shape, and the like. When an AC electrical signal having the same frequency as the resonance frequency is applied to the vibration member 32, the dust-proof member 31 bends and vibrates in a resonance state, so that the amplitude becomes maximum. Therefore, when removing dust and dirt adhering to the dustproof member 31 by vibration, it is preferable to apply an AC electrical signal having the same frequency as the resonance frequency to the vibration member 32 so that the effect is maximized. In addition, since an accurate resonance frequency may be unknown due to variations in dimensions and mass at the time of manufacture, attachment errors, and the like, the AC electrical signal applied to the vibration member 32 may be changed within a predetermined range.

  FIG. 5 shows a state where the dustproof member 31 is flexibly vibrated in a resonance state. FIG. 5A shows the state of bending vibration in the fifth-order vibration mode. This bending vibration has five antinodes and six nodes as shown in the figure. FIG. 5B shows the bending vibration in the ninth vibration mode. As shown in the figure, this flexural vibration has 9 antinodes and 10 nodes. In this way, by using a combination of a plurality of types of vibration modes and changing the position of the vibration node, it is possible to prevent dust and dust from remaining in the node portion without being removed. In addition, since the vibration mode demonstrated above is an example, you may use another vibration mode.

According to the embodiment described above, the following operational effects are obtained.
(1) The vibration member 32 expands and contracts in a direction substantially perpendicular to the plate surface of the plate-like dustproof member 31 and transmits the expansion and contraction motion to the dustproof member 31. The dustproof member 31 vibrates in a direction substantially perpendicular to the plate surface according to the expansion and contraction motion transmitted from the vibration member 32. Since it did in this way, the expansion-contraction movement of the vibration member 32 can be efficiently transmitted to the dust-proof member 31, and a vibration can be generated in the dust-proof member 31. As a result, dust and dirt attached to the plate surface of the dustproof member 31 can be effectively removed.

(2) The dustproof member 31 and the vibration member 32 are pressed by the bolts 34 and the nuts 35 in the direction in which the dustproof member 31 and the vibration member 32 approach each other. Since it did in this way, the expansion-contraction movement of the vibration member 32 can be transmitted to the dust-proof member 31 still more efficiently.

(3) With the dust-proof member 31 and the vibration member 32 sandwiched between the head of the bolt 34 and the nut 35, the nut 35 is screwed into the shaft portion of the bolt 34, whereby the dust-proof member 31 and the vibration member 32 was pressed. Since it did in this way, the dust-proof member 31 and the vibration member 32 can be pressed with a simple structure.

(4) The vibration member 32 is configured by laminating a plurality of piezoelectric elements. Since it did in this way, compared with the case where it does not laminate | stack, even if the applied voltage is low, the expansion / contraction motion with a big displacement amount can be produced in the vibration member 32. FIG.

  In the embodiment described above, the digital camera having the image sensor has been described as an example. However, the present invention can also be applied to a digital video camera.

  The embodiment and various modifications described above are merely examples, and the present invention is not limited to these contents as long as the features of the invention are not impaired.

It is a block diagram which shows the structure of the digital camera by one Embodiment of this invention. It is the top view and sectional drawing of an imaging device with which a dustproof device is installed. It is the top view and sectional drawing of an imaging device when a leaf | plate spring is removed. It is the top view and sectional drawing of a dustproof member, a vibration member, a washer, a volt | bolt, and a nut. It is a figure showing a mode when a dustproof member carries out bending vibration in the resonance state.

Explanation of symbols

1: CPU 2: Imaging device 3: Dustproof device 4: CCD
5: Photometry device 6: Sequence device 7: Flash device 8: Power supply unit 9: Display device in viewfinder 10: Display device 11: Controller 12: Memory card 13: Image processing unit 14: RAM
15: ROM 16: Operation member 100: Camera body 200: Shooting lens

Claims (6)

A plate-like dustproof member that prevents dust from adhering to the image sensor;
Vibration generating means for generating vibration in the dustproof member,
The vibration generating means expands and contracts in a direction substantially perpendicular to the plate surface of the dustproof member, and transmits the expansion and contraction motion to the dustproof member.
The dustproof device vibrates in a direction substantially perpendicular to the plate surface in accordance with the expansion and contraction motion transmitted from the vibration generating means. The dustproof device according to claim 1, wherein
A dustproof device, further comprising a pressing unit that presses the dustproof member and the vibration generating unit in a direction in which the dustproof member and the vibration generating unit approach each other. The dustproof device according to claim 2,
The pressing means includes a bolt whose shaft portion passes through a through hole provided in the dust-proof member and the vibration generating means, and a nut screwed to the shaft portion of the bolt,
The dustproof member and the vibration generating means are formed by screwing the nut onto the shaft portion of the bolt in a state where the dustproof member and the vibration generating means are sandwiched between the head of the bolt and the nut. A dustproof device that presses the dust. In the dustproof device according to any one of claims 1 to 3,
The vibration generating means is configured by stacking a plurality of piezoelectric elements. An image sensor that outputs an imaging signal of a subject based on an incident light beam;
A dust-proof member for preventing dust from adhering to the image sensor;
Vibration generating means for generating vibration in the dustproof member,
The vibration generating means expands and contracts in a direction substantially perpendicular to the plate surface of the dustproof member, and transmits the expansion and contraction motion to the dustproof member.
The image pickup apparatus, wherein the dust-proof member vibrates in a direction substantially perpendicular to the plate surface in accordance with the expansion and contraction motion transmitted from the vibration generating means. An imaging device according to claim 5;
A camera comprising recording control means for recording a captured image of the subject on a recording medium based on the imaging signal.

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