JP2011061382A - Imaging unit and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging unit equipped with a foreign material removal structure wherein the number of components and the assembly man-hour can be reduced and the reworkability can be improved, and to provide an imaging apparatus. <P>SOLUTION: The imaging apparatus includes: an image sensor; an optical member arranged ahead of the image sensor on the optical axis; a retaining member configured to retain the image sensor on the first surface and to retain the optical member on the second surface, i.e., the rear surface of the first surface; a vibration means for giving vibration to the optical member; a first sealing part which forms an enclosed space by sealing between the image sensor and the retaining member when the image sensor is fixed to the retaining member; and a second sealing part which forms an enclosed space by sealing between the optical member and the retaining member when the optical member is fixed to the retaining member. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image pickup unit and an image pickup apparatus, and more particularly to an image pickup unit that holds an optical member and an image pickup element disposed on an optical axis in an optical apparatus such as an image pickup apparatus.

In an imaging device such as a digital camera that captures a subject image by converting it into an electrical signal, the imaging light beam is received by the imaging device, a photoelectric conversion signal output from the imaging device is converted into image data, and a memory card, etc. Record on a recording medium.
A CCD (Charge Coupled Device), a CMOS sensor (Complementary Metal Oxide Semiconductor), or the like is used as the imaging device.
In such an image pickup apparatus, an optical low-pass filter and an infrared absorption filter are arranged on the subject side of the image pickup element. When foreign matter such as dust adheres to the surface of these filters, the attached portion becomes a black dot. The image appears in the photographed image, and the image looks poor.
In particular, in a digital single lens reflex camera with interchangeable lenses, mechanical operation parts such as shutters and quick return mirrors are arranged in the vicinity of the image sensor, and foreign matters such as dust generated from these operation parts are captured by the image sensor and filter. May adhere to the surface of
In addition, when the lens is replaced, foreign matter such as dust may enter the camera body from the opening of the lens mount and adhere to it.

In order to avoid such a phenomenon, Patent Document 1 proposes a technique for removing foreign matters such as dust attached to the surface of the optical element by vibrating the optical element on the subject side of the image pickup element with a piezoelectric element. Has been.
Here, as a means for vibrating such an optical element, a vibrating means for vibrating an optical member disposed on the optical axis is configured, and the optical element is resonantly vibrated in two or more vibration modes. The dust attached to the surface of the optical member is removed.

JP 2008-26564 A

However, in the method of Patent Document 1, since the imaging element holding member supported by the mirror box and the optical element holding member holding the optical element provided with the vibration means are separate, the number of parts is large. There is a problem that assembly man-hours increase.
In addition, since the optical element unit and the imaging element unit are sealed with a double-sided adhesive rubber sheet, there is a problem that it is difficult to peel off the double-sided adhesive during rework.

  In view of the above problems, the present invention provides an image pickup unit and an image pickup apparatus that can reduce the number of parts and the number of assembly steps in an image pickup unit having a foreign substance removal structure and can improve reworkability. The purpose is to do.

The present invention provides an imaging unit and an imaging apparatus configured as follows.
The imaging unit of this application is
An image sensor;
An optical member disposed in front of the optical axis with respect to the imaging element;
A holding member in which the optical element is held on the first surface and the optical member is held on a second surface which is the back surface of the first surface;
Excitation means for applying vibration to the optical member, and a first sealing portion that forms a sealed space by sealing between the imaging element and the holding member when fixing the imaging element to the holding member When,
A second sealing portion that seals between the optical member and the holding member to form a sealed space when the optical member is fixed to the holding member;
It is characterized by having.

  According to the present invention, an imaging unit and an imaging apparatus capable of reducing the number of parts and the number of assembly steps and improving reworkability in an imaging unit having a foreign matter removing structure can be realized. .

1 is a front perspective view of a digital single-lens reflex camera according to an embodiment of the present invention. It is a back side perspective view of the digital single-lens reflex camera concerning an embodiment of the invention. It is a block diagram which shows the electric constitution of the digital single-lens reflex camera which concerns on embodiment of this invention. It is a disassembled perspective view which shows schematic structure inside a camera for showing the surrounding structure of an imaging unit. It is a disassembled perspective view which shows the structure of an imaging unit. It is a figure for demonstrating the detail of a piezoelectric element. It is the sectional view on the AA line in FIG. It is the perspective view which decomposed | disassembled the image pick-up element from the imaging unit. It is the perspective view which decomposed | disassembled the optical low-pass filter from the imaging unit. It is a flowchart for demonstrating the operation | movement which removes foreign materials, such as dust adhering to the surface of an optical low-pass filter.

Next, an embodiment of the present invention will be described along the following items.
1. 1. Overall schematic configuration of camera 1-1. Mechanical configuration 1-2. Electrical configuration2. 2. Specific configuration of imaging unit 2-1. Schematic configuration of imaging unit inside camera 2-2. Configuration of imaging unit 2-3. Configuration of piezoelectric element 2-4. Configuration of sealing member 2-5. 2. Disassembly and assembly of imaging unit Foreign matter removal operation.

1. Overall configuration of the camera (FIGS. 1 to 3)
1-1. Mechanical configuration (Figs. 1 and 2)
In the present embodiment, the following digital single-lens reflex camera can be configured by applying the present invention. First, a mechanical configuration of the overall schematic configuration of the camera will be described.
FIG. 1 is an external view of a digital single-lens reflex camera according to the present embodiment, and is a perspective view of the camera as viewed from the front side (subject side), showing a state in which the taking lens unit is removed.
As shown in FIG. 1, the camera body 1 is provided with a grip portion 1 a that protrudes toward the subject side so that the photographer can stably grip the camera body during shooting.
A photographic lens unit (200a) (not shown in FIGS. 1 and 2) is detachably fixed to the mount portion 2 of the camera body 1.
The mount contact 21 enables communication of a control signal, a status signal, a data signal, and the like between the camera body 1 and the photographing lens unit and supplies power to the photographing lens unit.
The mount contact 21 may be configured not only for electrical communication but also for optical communication, voice communication, and the like. A lens lock release button 4 that is pushed in when removing the taking lens unit is disposed beside the mount unit 2.

In the camera body 1, there is provided a mirror box 5 that guides a photographing light beam that has passed through the photographing lens, and a main mirror (quick return mirror) 6 is disposed in the mirror box 5.
The main mirror 6 is held at an angle of 45 ° with respect to the photographing optical axis in order to guide the photographing light flux toward the penta roof mirror 22 (see FIG. 3), and the image sensor 33 (see FIG. 3). Therefore, it is possible to take a state of being held at a position retracted from the photographing light flux.
On the grip 1a on the upper side of the camera, a release button 7 as a start switch for shooting, a main operation dial 8 for setting a shutter speed and a lens aperture value according to an operation mode at the time of shooting, and an upper surface of the shooting system An operation mode setting button 10 is arranged.
Some of the operation results of these operation members are displayed on the LCD display panel 9. The release button 7 is configured such that SW1 (7a in FIG. 3) is turned on in the first stroke and SW2 (7b in FIG. 3) is turned on in the second stroke. The top operation mode setting button 10 is used for setting whether the release button 7 is pressed once for continuous shooting or shooting for only one frame, setting for the self-shooting mode, and the like. The setting status is displayed on the LCD display panel 9.
A flash unit 11 that pops up with respect to the camera body 1, a shoe groove 12 for attaching a flash, and a flash contact 13 are provided in the center of the upper part of the camera.
A shooting mode setting dial 14 is arranged on the upper right side of the camera.
An external terminal lid 15 that can be opened and closed is provided on the side surface opposite to the grip 1a of the camera. Inside the external terminal lid 15, a video signal output jack 16 and a USB output connector 17 are housed as external interfaces.

FIG. 2 is an external view of the digital single-lens reflex camera according to the present embodiment, and is a perspective view of the camera viewed from the photographer side (back side).
As shown in FIG. 2, a finder eyepiece window 18 is provided above the back of the camera. In addition, a color liquid crystal monitor 19 capable of displaying an image is provided near the center of the back of the camera.
A sub operation dial 20 is arranged beside the color liquid crystal monitor 19. The sub operation dial 20 plays an auxiliary role in the function of the main operation dial 8.
For example, in the AE mode of the camera, it is used to set an exposure correction amount for the appropriate exposure value calculated by the automatic exposure device.
In the manual mode in which each of the shutter speed and the lens aperture value is set according to the user's will, the shutter speed is set with the main operation dial 8 and the lens aperture value is set with the sub operation dial 20.
The sub operation dial 20 is also used to select display of a photographed image displayed on the color liquid crystal monitor 19.

Further, a main switch 43 for starting or stopping the operation of the camera and a cleaning instruction operation member 44 for operating the cleaning mode are arranged on the back of the camera.
As will be described in detail later, the cleaning instruction operation member 44 is for instructing an operation to screen off foreign matters such as dust adhering to the surface of the optical low-pass filter 410.
The cleaning mode can be arbitrarily operated using the cleaning instruction operation member 44, and can be automatically operated when the main switch 43 is turned on, turned off, or both.

1-2. Electrical configuration (Figure 3)
FIG. 3 is a block diagram showing the main electrical configuration of the digital single-lens reflex camera according to the present embodiment. In addition, the same code | symbol is attached | subjected to the part which is common in FIG.
A central processing unit (hereinafter, referred to as “MPU”) 100 formed of a microcomputer built in the camera body 1 controls operation of the camera, and executes various processes and instructions for each element.
The EEPROM 100a built in the MPU 100 can store time information of the time measuring circuit 109 and other information.
Connected to the MPU 100 are a mirror drive circuit 101, a focus detection circuit 102, a shutter drive circuit 103, a video signal processing circuit 104, a switch sensor circuit 105, and a photometric circuit 106.
Further, an LCD drive circuit 107, a battery check circuit 108, a time measurement circuit 109, a power supply circuit 110, and a piezoelectric element drive circuit 111 are connected.
These circuits operate under the control of the MPU 100.
The MPU 100 communicates with the lens control circuit 201 in the photographing lens unit 200a via the mount contact 21. The mount contact 21 also has a function of transmitting a signal to the MPU 100 when the photographing lens unit 200a is connected.
Accordingly, the lens control circuit 201 communicates with the MPU 100 and drives the photographing lens 200 and the diaphragm 204 in the photographing lens unit 200a via the AF driving circuit 202 and the diaphragm driving circuit 203.
In FIG. 3, only one photographing lens 200 is shown for convenience, but in actuality, it is constituted by a large number of lens groups.

The AF drive circuit 202 is constituted by, for example, a stepping motor, and adjusts the focus of the photographing light flux to the imaging element 33 by changing the focus lens position in the photographing lens 200 under the control of the lens control circuit 201.
The aperture driving circuit 203 is configured by, for example, an auto iris or the like, and changes the aperture 204 under the control of the lens control circuit 201 to obtain an optical aperture value.
The main mirror 6 guides the photographic light beam passing through the photographic lens 200 to the penta roof mirror 22 and transmits a part thereof while being held at an angle of 45 ° with respect to the photographic optical axis shown in FIG. Guide to submirror 30.
The sub mirror 30 guides the photographic light beam transmitted through the main mirror 6 to the focus detection sensor unit 31.
The mirror drive circuit 101 is composed of, for example, a DC motor and a gear train, and drives the main mirror 6 to a position where the subject image can be observed by the finder and a position where the subject image is retracted from the photographing light beam.
When the main mirror 6 is driven, the sub mirror 30 is simultaneously moved to a position for guiding the photographing light beam to the focus detection sensor unit 31 and a position for retracting from the photographing light beam.
The focus detection sensor unit 31 is composed of a field lens, a reflection mirror, a secondary imaging lens, a diaphragm, a line sensor composed of a plurality of CCDs, etc. arranged in the vicinity of an imaging surface (not shown), and a phase difference type focus detection. I do.
A signal output from the focus detection sensor unit 31 is supplied to the focus detection circuit 102, converted into a subject image signal, and then transmitted to the MPU 100.
The MPU 100 performs focus detection calculation by the phase difference detection method based on the subject image signal.
Then, the defocus amount and the defocus direction are obtained, and based on this, the focus lens in the photographing lens 200 is driven to the in-focus position via the lens control circuit 201 and the AF drive circuit 202.

The penta roof mirror 22 converts and reflects the photographing light beam reflected by the main mirror 6 into an erect image.
The photographer can observe the subject image from the viewfinder eyepiece window 18 through the viewfinder optical system.
The penta roof mirror 22 also guides a part of the photographic light beam to the photometric sensor 23. The photometric circuit 106 obtains the output of the photometric sensor 23, converts it into a luminance signal for each area on the observation surface, and outputs it to the MPU 100. The MPU 100 calculates an exposure value based on the luminance signal.
The shutter unit (mechanical focal plane shutter) 32 has a shutter front curtain in a light shielding position and a shutter rear curtain in an exposure position when a photographer observes a subject image with a finder.
Next, at the time of shooting, the shutter front curtain travels from the light shielding position to the exposure position, passes light from the subject, and the image sensor 33 captures an image.
After the elapse of a desired shutter time, the shutter trailing curtain moves from the exposure position to the light shielding position, and the photographing is completed.
The mechanical focal plane shutter 32 is controlled by the shutter drive circuit 103 that has received a command from the MPU 100.
The imaging unit 400 is a unit in which an optical low-pass filter 410, a piezoelectric element 430 that is a piezoelectric member, and an imaging element 33 are combined with other components described later. The image sensor 33 photoelectrically converts a subject image. In this embodiment, a CMOS sensor is used, but there are various other types such as a CCD type, a CMOS type, and a CID type. A device may be employed.
The optical low-pass filter 410 disposed in front of the image sensor 33 is a single birefringent plate made of quartz and has a rectangular shape.
The piezoelectric element 430 is a single-plate piezoelectric element (piezo element) that is vibrated by the piezoelectric element drive circuit 111 that constitutes the vibration means that receives an instruction from the MPU 100, and transmits the vibration to the optical low-pass filter 410. It is configured.

The clamp / CDS (correlated double sampling) circuit 34 performs basic analog processing before A / D conversion, and the clamp level can be changed.
The AGC (automatic gain adjusting device) 35 performs basic analog processing before A / D conversion, and can change the AGC basic level.
The A / D converter 36 converts the analog output signal of the image sensor 33 into a digital signal.

The video signal processing circuit 104 performs overall image processing by hardware such as gamma / knee processing, filter processing, and information composition processing for monitor display on the digitized image data.
The image data for monitor display from the video signal processing circuit 104 is displayed on the color liquid crystal monitor 19 via the color liquid crystal drive circuit 112. The video signal processing circuit 104 can also store image data in the buffer memory 37 through the memory controller 38 in accordance with an instruction from the MPU 100.
Further, the video signal processing circuit 104 can also perform image data compression processing such as JPEG. When continuous shooting is performed, such as continuous shooting, image data can be temporarily stored in the buffer memory 37, and unprocessed image data can be sequentially read out through the memory controller 38.
Thereby, the video signal processing circuit 104 can sequentially perform image processing and compression processing regardless of the speed of the image data input from the A / D converter 36.
The memory controller 38 has a function of storing the image data input from the external interface 40 in the memory 39 and outputting the image data stored in the memory 39 from the external interface 40.
The external interface 40 corresponds to the video signal output jack 16 and the USB output connector 17 in FIG. As the memory 39, a flash memory that can be attached to and detached from the camera body is used.

The switch sense circuit 105 transmits an input signal to the MPU 100 according to the operation state of each switch.
The switch SW1 (7a) is turned on by the first stroke (half press) of the release button 7. The switch SW2 (7b) is turned on by the second stroke (full press) of the release button 7. When the switch SW2 (7b) is turned on, an instruction to start photographing is transmitted to the MPU 100.
Further, the main operation dial 8, the sub operation dial 20, the photographing mode setting dial 14, the main switch 43, and the cleaning instruction operation member 44 are connected. The LCD drive circuit 107 drives the LCD display panel 9 and the in-finder liquid crystal display device 41 in accordance with instructions from the MPU 100.
The battery check circuit 108 performs a battery check according to an instruction from the MPU 100 and transmits the detection result to the MPU 100.
The power supply 42 supplies power to each element of the camera.
The time measuring circuit 109 measures the time and date from when the main switch 43 is turned off to when it is turned on, and transmits the measurement result to the MPU 100 in accordance with an instruction from the MPU 100.

2. Specific configuration of imaging unit (FIGS. 4 to 9)
2-1. Schematic configuration of the imaging unit inside the camera (FIG. 4)
Next, a schematic configuration of the imaging unit 400 in the present embodiment will be described.
As shown in FIG. 4, the mirror box 5 and the shutter unit 32 are arranged in this order from the subject side on the subject side of the main body chassis 300 that is the skeleton of the camera body. An imaging unit 400 is disposed on the photographer side of the main body chassis 300. The image pickup unit 400 is adjusted and fixed so that the image pickup surface of the image pickup element 33 is parallel to the attachment surface of the mount portion 2 as a reference to which the photographing lens unit is attached with a predetermined distance.

2-2. Configuration of imaging unit (Fig. 5)
FIG. 5A is a perspective view seen from the front side of the optical axis, and FIG. 5B is a perspective view seen from the rear side of the optical axis.
As shown in FIG. 5, the optical low-pass filter 410 is a single birefringent plate made of quartz, and its shape is rectangular.
This optical low-pass filter 410 corresponds to an optical member disposed in front of the optical axis of the image sensor 33 and on the optical axis.
The optical low-pass filter 410 has a peripheral portion 410b in which the piezoelectric element 430 is disposed on one side of the effective imaging area 410a, and the direction orthogonal to the imaging optical axis center (camera horizontal direction) is asymmetric.
An optical coating is applied to the surface of the optical low-pass filter 410 as described above.

The piezoelectric element 430 has a single-plate rectangular strip shape, and is arranged so that the long side of the piezoelectric element 430 is parallel to the short side (side) of the optical low-pass filter 410 at the peripheral portion 410 b of the optical low-pass filter 410. To be adhered and held (attached).
The piezoelectric element 430 corresponds to a rectangular vibration means for vibrating the optical member.
That is, the piezoelectric element 430 is attached in parallel to one side of the four sides on the optical low-pass filter 410 and vibrates the optical low-pass filter 410 in a wave shape so as to have a plurality of nodes parallel to the one side.

Reference numeral 610 denotes a holding member that holds the optical low-pass filter 410 and the image sensor 33 made of resin or metal.
In the holding member 610, the first sealing member 620 is integrated with the first surface which is the photographer side, and the second sealing member 630 is integrated with the second surface which is the subject side which is the back surface of the first surface. Are molded.
The sealing members 620 and 630 are elastic members, and may be rubber, or a polymer such as urethane foam or plastic may be used as long as it is an elastic body.
In the present embodiment, the holding member 610 and the sealing members 620 and 630 are integrally formed, but may be separate.
The image sensor 33 is in close contact with the sealing member 620 of the holding member 610 and is fixed to the holding member 610 with screws 500 at a position different from the close contact portion.

Reference numeral 440 denotes an urging member, which abuts at four positions outside the effective photographing area 410 a of the optical low-pass filter 410 and urges the photographer side in the optical axis direction, and is fixed to the holding member 610 with screws 510.
The optical low-pass filter 410 is held in close contact with the holding member 610 by the second sealing member 630.
Reference numeral 470 denotes a piezoelectric element flexible printed circuit board for applying a voltage to the piezoelectric element 430, and is bonded and fixed to the piezoelectric element 430.
The piezoelectric element 430 mainly expands and contracts in a direction orthogonal to the optical axis by applying a voltage, and resonates (vibrates) the optical low-pass filter 410.
Thereby, the foreign material adhering to the surface of the optical low-pass filter 410 can be eliminated.

2-3. Structure of piezoelectric element (Fig. 6)
As shown in FIG. 6, the B surface of the piezoelectric element 430 is divided into a + phase for exciting standing wave vibration in the optical low-pass filter 410 and a G phase.
In addition, the C surface of the piezoelectric element 430 is electrically connected by a conductive material (not shown) or the like and is kept at the same potential as the G phase of the B surface.
A flexible printed circuit board 470 for piezoelectric elements is fixed to the B surface by bonding or the like, and a predetermined voltage can be independently applied to the + phase and the G phase.
The C surface is fixed to the optical low-pass filter 410 by bonding or the like, and the piezoelectric element 430 and the optical low-pass filter 410 are configured to move integrally.
Reference numeral 460 denotes an optical member in which a phase plate (depolarization plate), an infrared cut filter, and a birefringent plate whose refractive direction is 90 ° different from that of the optical low-pass filter 410 are bonded together, and are bonded and fixed to the optical low-pass filter holding member. The
By adopting the above configuration, the optical low-pass filter 410 is sandwiched between the urging member 440 and the second sealing member 630 and supported in a freely oscillating manner.

2-4. Configuration of sealing member (FIG. 7)
Next, the configuration of the holding member 610 and the sealing members 620 and 630 will be described in detail with reference to FIG. 7 showing a cross-sectional view taken along line AA in FIG.
The first sealing member 620 is integrated with the holding member 610 by integral molding, and is in contact with the image sensor 33.
The sealing member 620 is an elastic member such as rubber or elastomer, and can be integrated with the holding member 610 by two-color molding.
The imaging element 33 is completely fixed by a holding member 610 and a screw 500 fastening portion. At this time, the sealing member 620 is elastically deformed by being urged with a constant force between the holding member 610 and the imaging element 33, and the space on the imaging range side can be sealed.
The contact portion of the sealing member 620 with the image sensor 33 is formed with one or more convex shapes.
Further, the optical member 460 is held by being bonded to the outer periphery of a predetermined holding portion of the holding member 610.
As a result, the space surrounded by the holding member 610, the imaging element 33, the first sealing member 620, and the optical member 460 is sealed, and a sealed space that prevents entry of foreign matters such as dust is formed.

On the other hand, the second sealing member 630 is also integrated with the holding member 610 by integral molding, and the surface on the subject side is in contact with the optical low-pass filter 410.
Since the optical low-pass filter 410 is urged toward the image sensor 33 due to the elasticity of the urging member 440, the sealing member 630 is elastically deformed and is in close contact with the optical low-pass filter 410 and the holding member 610 without a gap.
As a result, the space surrounded by the optical low-pass filter 410, the holding member 610, the second sealing member 630, and the optical member 460 is sealed, and a sealed space that prevents entry of foreign matters such as dust is formed.
The optical low-pass filter 410 and the second sealing member 630 may be constituted by an elastic member so as to also serve as a vibration transmission member when applying vibration by the vibration means.
However, although the holding member 610 and the plurality of optical elements 410 and 460 or the image sensor 33 can form a sealed space with the above-described structure, foreign matter may inevitably be mixed in the assembly process.
For this reason, when foreign matter intrusion is found by inspection in the completion process of the imaging unit 400, it is required to disassemble the imaging unit 400, clean the foreign matter, and reassemble.

2-5. Disassembly and assembly of the imaging unit (Figs. 8 and 9)
Next, disassembly and assembly of the imaging unit in the present embodiment will be described.
Reference numeral 710 shown in FIGS. 8A and 8B denotes a unit in which the image sensor 33 is removed from the image pickup unit 400.
By forming a sealed space with the sealing member 620, the image pickup device 33 can be removed simply by removing the screw 500.
When the conventional image sensor unit and optical element unit are closely fixed with an adhesive sheet, there are many problems such as damage to the member when peeled off during rework and the adhesive sheet cannot be reused.
Compared with this, if it is the structure of this invention, the process of a decomposition | disassembly, a foreign material cleaning, and an assembly can be performed easily.

720 shown in FIGS. 9A and 9B is a unit in which the biasing member 440, the optical low-pass filter 410, the piezoelectric element 430, and the piezoelectric element flexible printed circuit board 470 are removed from the imaging unit 400.
Even when foreign matter intrusion in the second sealing member 630 and the optical low-pass filter 410 is confirmed, the inside of the sealed space can be cleaned again by removing the biasing member 440.
As described above, as the configuration in which the holding member 610 holds the plurality of optical elements 410 and 460 and the imaging element 33, the first sealing member 620 and the second sealing member 630 are integrally molded, It is possible to reduce assembly man-hours.
Further, when it is confirmed that foreign matter has entered the sealed space during the assembly process, it can be easily disassembled, cleaned, and assembled as described above, thereby improving workability.

3. Foreign substance removal operation (FIG. 10)
Next, with reference to FIG. 10, an operation for removing foreign matters such as dust attached to the surface of the optical low-pass filter 410 will be described.
First, in step S1, it is determined whether or not the main switch 43 is turned on. When the power is turned on, in step 2, a process for starting the camera system is performed, the power supply circuit 110 is controlled to supply power to each circuit, the system is initialized, and the camera can be operated for shooting. The camera system ON operation is performed.
Next, in Step 3, it is determined whether or not the cleaning instruction operation member 44 has been operated by the photographer. If it has been operated, the process proceeds to Step 4, and if it has not been operated, the process proceeds to Step 5.
In this embodiment, the cleaning instruction operation member 44 is provided, but the present invention is not limited to this.
For example, the operation member for instructing the shift to the cleaning mode is not limited to a mechanical button, but is an instruction from a menu displayed on the color liquid crystal monitor 19 using a cursor key, an instruction button, or the like. Also good.
Next, in step 4, in response to a command to start the cleaning mode, the camera body 1 is shifted to the cleaning mode.
First, the power supply circuit 110 supplies power necessary for the cleaning mode to each part of the camera body 1.
In parallel with this, the remaining battery level of the power source 42 is detected, and the result is transmitted to the MPU 100.
Upon receiving the cleaning mode start signal, the MPU 100 sends a drive signal to the piezoelectric element drive circuit 111. When the piezoelectric element drive circuit 111 receives a drive signal from the MPU 100, the piezoelectric element drive circuit 111 generates a periodic voltage that excites the standing wave vibration of the optical low-pass filter 410 and applies it to the piezoelectric element 430.
The periodic voltage is sequentially changed within a certain range of frequencies including the frequency for exciting the standing wave oscillation.
The piezoelectric element 430 expands and contracts according to the applied voltage, and causes the optical low-pass filter 410 to generate standing wave vibration.
When the cleaning mode ends, the process proceeds to step 5.

Next, in step 5, the camera operates by receiving signals from the switch SW1 (7a), the switch SW2 (7b), the main operation dial 8, the sub operation dial 20, the shooting mode setting dial 14, and other switches.
The camera operation is a generally known mode for taking and setting a camera, and a detailed description thereof is omitted here.
Next, in step 6, it is determined whether the power is turned off by the main switch 43 when the camera is in a standby state. If turned off, the process proceeds to step 7. If not turned off, the process returns to step 3.
Next, in step 7, after executing the same cleaning mode as in step 4, the process proceeds to step 8.
Here, in the cleaning mode in Step 7, parameters such as the driving frequency, driving time, and control method of the piezoelectric element 430 may be different from those in Step 4 in consideration of the power consumption and operation time of the camera. There is no.
In step 8, the MPU 100 controls to terminate each circuit, stores necessary information in the EEPROM 100a, and controls the power supply circuit 110 to turn off the power supply to each circuit. Do.

As described above, the cleaning mode is executed not only at an arbitrary timing intended by the photographer but also when the power is turned off.
That is, the camera system OFF operation is performed after the operation of removing the foreign matter adhering to the surface of the optical low-pass filter 410 is performed.
Here, there are various kinds of foreign matters attached to the surface of the optical low-pass filter 410, but generally, if left for a long time with foreign matters attached, it may be difficult to remove even if vibration is applied in the cleaning mode. Elucidated experimentally.
This is thought to be due to increased adhesion of liquid bridging force due to condensation due to changes in the environment (temperature and humidity), and adhesion due to repeated swelling and drying of dust due to environmental changes. It is done.
In addition, in an elastic material such as rubber, oil and fat contained in the rubber bleeds and adheres over time.
Therefore, if the cleaning mode is executed at the timing of power-off operation, which is likely to be unused for a long period of time, it is highly likely that it is difficult to remove foreign substances. It is more efficient and effective than the operation timing.
In this embodiment, the power OFF operation by the main switch 43 has been described. However, a camera system OFF operation similar to that at the time of power OFF may be executed after a predetermined time has elapsed in the power ON state.
In this case, it goes without saying that the same effect can be obtained if the cleaning mode is performed in advance.
The optical member referred to in the present invention is not limited to the optical low-pass filter 410.
For example, the material of the birefringent plate may be lithium niobate instead of quartz.
Further, an optical low-pass filter constituted by bonding a birefringent plate, a phase plate, and an infrared absorption filter, or an infrared absorption filter alone may be vibrated.
Moreover, you may make it the structure which vibrates to the glass plate single-piece | unit arrange | positioned in front of the birefringent plate.

33: Imaging element 400: Imaging unit 410: Optical low-pass filter 430: Piezoelectric element 440: Biasing member 460: Optical member 470: Flexible printed circuit board for piezoelectric element 500: Screw (for fixing the imaging element)
510: Screw (for urging member fixing)
610: holding member 620: first sealing member 630: second sealing member

Claims (4)

An image sensor;
An optical member disposed in front of the optical axis with respect to the imaging element;
A holding member in which the optical element is held on the first surface and the optical member is held on a second surface which is the back surface of the first surface;
Excitation means for applying vibration to the optical member;
When fixing the imaging device to the holding member, a first sealing portion that forms a sealed space by sealing between the imaging device and the holding member;
A second sealing portion that seals between the optical member and the holding member to form a sealed space when the optical member is fixed to the holding member;
An imaging unit comprising:   The imaging unit according to claim 1, wherein the optical member and the second sealing portion are formed of an elastic member, and also serve as a vibration transmission member when the vibration is applied by the excitation unit. Said 1st sealing part and said 2nd sealing part are comprised with the elastic member,
The imaging unit according to claim 1, wherein the imaging unit is integrally formed with the holding member.   An imaging apparatus comprising the imaging unit according to claim 1.

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