JP2009159268A - Optical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove foreign matters such as dusts adhering to the front surface of an optical member within a short period of time with a small amount of electrical power. <P>SOLUTION: An optical apparatus includes an imaging element as a member to which light is projected to focus an optical image, an infrared cutting filter arranged in front of the imaging element, a piezoelectric element for giving vibration to the infrared cutting filter, and an elastic member that is arranged surrounding the sight of the imaging element to be placed in contact with the infrared cutting filter. In this optical apparatus, the center of the elastic member is arranged in the upper side with respect to the center of the imaging field and the upward amplitude is larger than the downward amplitude with respect to the center of the imaging field. Accordingly, more stable removing performance can be provided by lowering probability for re-adhesion of foreign matters, which have been once separated from the infrared cutting filter, within the imaging field. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical device such as an imaging device, and more particularly to a technique for removing foreign matters such as dust attached to the surface of an optical member disposed on an optical axis.

  In an imaging apparatus such as a digital camera that captures an image by converting an image signal into an electrical signal, an imaging light beam is received by an imaging element such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). Then, the photoelectric conversion signal output from the image sensor is converted into image data and recorded on a recording medium such as a memory card. In such an imaging apparatus, an optical low-pass filter and an infrared cut filter are disposed in front of the imaging element (subject side).

  In this type of image pickup apparatus, when foreign matter such as dust adheres to the cover glass of the image pickup element or the surface of these filters, the foreign matter becomes a black dot and appears in the photographed image, resulting in a deterioration in the appearance of the image.

  Especially in digital SLR cameras 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 covered by the cover of the image sensor. May adhere to glass or filter surfaces. 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.

  Therefore, in Patent Document 1, a dustproof screen that transmits a photographic light beam is provided on the subject side of an image sensor, and this is vibrated by a piezoelectric element, thereby removing foreign matters such as dust attached to the surface of the dustproof screen. Proposed.

JP 2003-319222 A

  In Patent Document 1, the circular dust screen is disposed so that the center of the dust screen substantially coincides with the center of the imaging field of view, and generates a membrane vibration that is symmetrical with respect to the optical axis in a plane perpendicular to the optical axis. In this way, foreign matters such as dust adhering to the dust screen are removed.

  However, in this technique, the amplitude near the center of the dust screen is large and the amplitude at the end of the dust screen tends to be small because of the characteristics of the membrane vibration and the dust screen holding structure. For this reason, the foreign matter adhering to a region having a small vertical amplitude with respect to the imaging field of view does not fly far from the dust screen because of a small acceleration applied from the dust screen, and falls by gravity near the dust screen. During the fall, the foreign matter once removed from the dust screen may reattach within the field of view of the dust screen, and stable dust control performance cannot be obtained.

  In order to drop the reattached foreign matter again, a solution to increase the vibration time for removing the foreign matter can be considered, but in that case, a great deal of time is spent on the foreign matter removing operation that is not related to imaging, which is the intended use. As a result, the comfortable feeling of use of the imaging apparatus is impaired. In addition, if the vibration time for removing the foreign matter is lengthened, more power is consumed and the number of shootable images is reduced. This also impairs the comfortable feeling of use of the imaging apparatus.

  Another solution is to apply a large voltage to the piezoelectric element to raise the amplitude of the entire dust screen so that foreign matter is scattered far away even at the minimum amplitude, but this also increases power consumption. Will be invited. In addition, due to the configuration of the imaging device, the dust screen is often made of thin and easily broken optical glass, and there is a problem that the risk of the dust screen being damaged increases by giving a large amplitude.

  The present invention has been made in view of the above problems, and an object of the present invention is to enable removal of foreign matters such as dust attached to the surface of an optical member in a short time and with low power.

  An optical device according to the present invention includes a projection member on which an optical image is formed, an optical member disposed in front of the projection member, and a vibration member that vibrates the optical member, the optical member Is characterized in that the amplitude on the upper side is larger than the amplitude on the lower side with respect to the center of the visual field of the projection target member.

  According to the present invention, it is possible to remove foreign matters such as dust attached to the surface of the optical member in a short time and with low power.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
(First embodiment)
1 and 2 are external views of a digital single-lens reflex camera according to the present embodiment. FIG. 1 is a front perspective view of the camera as viewed from the subject side, and shows a state in which the taking lens unit is removed. FIG. 2 is a rear perspective view of the camera as seen from the photographer side.

  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 (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 right above 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.

  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 member.

  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.1 and FIG.2. 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 sense 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 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 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 via the AF driving circuit 202 and the diaphragm driving circuit 203. In FIG. 3, only one photographing lens is shown for the sake of convenience, but actually, it is constituted by a large number of lens groups.

  The AF driving circuit 202 is configured by, for example, a stepping motor, and changes the focus lens position in the photographing lens 200 under the control of the lens control circuit 201 so as to adjust the photographing light beam to be focused on the image sensor 33. 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 photographing 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 imaging light flux to the focus detection sensor unit 31 and a position for retracting from the imaging light flux.

  The focus detection sensor unit 31 includes a field lens, a reflection mirror, a secondary imaging lens, a diaphragm, a line sensor including a plurality of CCDs, and the like that are arranged in the vicinity of an imaging surface (not shown). Perform detection. 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 is in a state of blocking the photographing light beam during imaging standby, that is, when the photographer is observing the subject image with the viewfinder. At the time of imaging, a desired exposure time is obtained by a time difference between a front blade group and a rear blade group (not shown) according to a release signal. The shutter unit 32 is controlled by the shutter drive circuit 103 that has received an instruction from the MPU 100.

  In the imaging unit 400, the infrared cut filter 410, the optical low-pass filter 420, the piezoelectric element 430, and the imaging element 33 are unitized together with other components described later. The detailed configuration will be described later.

  The infrared cut filter 410 has a substantially rectangular shape, and cuts unnecessary infrared rays of the light beam incident on the image sensor 33. The surface of the infrared cut filter 410 is covered with a conductive material in order to prevent foreign matter from adhering. In the present embodiment, the infrared cut filter 410 corresponds to an optical member disposed in front of the projection target member.

  The optical low-pass filter 420 has a substantially rectangular shape, and is formed by laminating a plurality of birefringent plates and phase plates made of quartz or the like. The optical low-pass filter 420 separates the light beam incident on the image sensor 33 into a plurality of light beams, and effectively reduces the generation of false resolution signals and false color signals.

  The piezoelectric element 430 is driven by the piezoelectric element drive circuit 111 that has received an instruction from the MPU 100, and is configured to vibrate integrally with the infrared cut filter 410. In the present embodiment, the piezoelectric element 430 corresponds to a vibration member that applies vibration to the optical member.

  The image sensor 33 converts an optical image of a subject into an electrical signal. In this embodiment, a CMOS type imaging device is used, but there are various other types such as a CCD type, a CMOS type, and a CID type, and any type of imaging device may be adopted. The light received in the area of the visual field 33a (hereinafter referred to as “imaging visual field 33a”) (see FIG. 13) of the imaging element 33 is imaged. In general, the center of the imaging field of view 33a coincides with the lens optical axis of the photographing lens 200. However, in some cases, such as crop photography in which only a part of the pixels of the imaging element 33 is used for imaging. In the present embodiment, the image sensor 33 corresponds to a projection member on which an optical image is formed.

  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 driving 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.

  Hereinafter, the imaging unit 400 will be described. FIG. 4 is an exploded perspective view showing a schematic configuration inside the camera for explaining the peripheral structure of the imaging unit 400. A mirror box 5 and a 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 spaced a predetermined distance from and parallel to the attachment surface of the mount unit 2 that serves as a reference to which the photographing lens unit is attached.

  FIG. 5 is an exploded perspective view showing the configuration of the imaging unit 400. The imaging unit 400 is roughly composed of a vibration unit 470, an elastic member 450, and an imaging element unit 500. As will be described in detail later, the vibration unit 470 is fixed to the image sensor unit 500 in a manner that sandwiches the elastic member 450, and the elastic member 450 is sandwiched between the infrared cut filter 410 and the image sensor unit 500 of the vibration unit 470.

  First, the image sensor unit 500 will be described with reference to FIGS. 5 and 6. The image sensor unit 500 includes an image sensor 33 that converts an optical image of a subject into an electrical signal. Specifically, in the image sensor unit 500, 510 is a fixing member, which holds the image sensor 33 and fixes the biasing member 460 of the vibration unit 470. Reference numeral 520 denotes a circuit board on which an electric circuit of the imaging system is mounted, and is arranged on the photographer side of the fixing member 510. Reference numeral 530 denotes a shield case made of conductive metal or the like. Reference numeral 540 denotes a light shielding member in which an opening corresponding to the effective area of the photoelectric conversion surface of the image sensor 33 is formed, and is disposed on the subject side of the fixed member 510. An optical low-pass filter holding member 550 holds the optical low-pass filter 420.

  The fixing member 510 has a positioning pin portion 510 a for positioning with the biasing member 460 of the vibration unit 470. Further, a screw hole 510b for fixing the circuit board 520 and the shield case 530 with screws is provided. Moreover, it has a screw hole 510c for fixing the urging member 460 (fixing portion 460b) of the vibration unit 470 with a screw.

  6 is a cross-sectional view taken along line AA in FIG. The object-side surface of the light shielding member 540 is in contact with the optical low-pass filter 420, and the photographer-side surface is in contact with the cover glass 33 b of the image sensor 33. Double-sided tape is fixed to the subject side and the photographer side of the light shielding member 540, and the optical low-pass filter 420 is fixed and held on the cover glass 33b of the image sensor 33 by the double-sided tape of the light shielding member 540. As a result, the space between the optical low-pass filter 420 and the cover glass 33b of the image sensor 33 is sealed by the light shielding member 540, thereby forming a sealed space that prevents entry of foreign matters such as dust. Note that the piezoelectric element 430 is fixed to the imaging element 33 side of the infrared cut filter 410 as shown in the figure.

  The circuit board 520 is provided with a screw escape hole 520a. The shield case 530 is provided with a screw escape hole 530a. The circuit board 520 and the shield case 530 are secured to the fixing member 510 with screws using screw escape holes 520a, screw escape holes 530a, and screw holes 510b. The shield case 530 is connected to a ground potential on the circuit in order to protect the electric circuit from static electricity and the like.

  The optical low-pass filter holding member 550 is fixed to the cover glass 33 b of the image sensor 33 by the double-sided tape of the light shielding member 540. The optical low-pass filter 420 is positioned at the opening of the optical low-pass filter holding member 550, and is fixed and held on the light shielding member 540 with double-sided tape.

  7 and 8 are perspective views of the vibration unit 470. FIG. As shown in FIGS. 7 and 8, the urging member 460 includes left and right positioning portions 460 a for positioning with the fixing member 510 of the imaging element unit 500. Moreover, it has the right and left fixing | fixed part 460b for fixing to the fixing member 510 (screw stop). Moreover, it has a frame-shaped holding part 460c for fixing and holding the infrared cut filter 410. Moreover, it has the left and right arm portions 460d for applying a biasing force that biases the infrared cut filter 410 toward the image sensor unit 500. The infrared cut filter 410 is fixed to the frame-shaped holding portion 460c by adhesion or the like.

  The vibration unit 470 is positioned with respect to the imaging element unit 500 by using the positioning portion 460a of the biasing member 460 and the positioning pin portion 510a of the fixing member 510. In this state, the vibration unit 470 is fixed to the image sensor unit 500 with screws using the fixing portion 460b of the biasing member 460 and the screw holes 510c of the fixing member 510 so as to sandwich the elastic member 450.

  The subject-side surface of the elastic member 450 is in contact with the infrared cut filter 410, and the photographer-side surface is in contact with the optical low-pass filter 420. Since the infrared cut filter 410 is urged toward the image sensor unit 500 by the urging force generated by the arm portion 460d of the urging member 460, the infrared cut filter 410 is in close contact with the elastic member 450 without any gap, and the elastic member 450 and the optical low pass. Similarly, the filter 420 is in close contact with no gap. As a result, the space between the infrared cut filter 410 and the optical low-pass filter 420 is sealed by the elastic member 450 to form a sealed space that prevents entry of foreign matters such as dust.

  Here, FIG. 9 shows a relative positional relationship between the elastic member 450 and the imaging visual field 33a. The imaging visual field 33a is indicated by oblique lines. The imaging field 33a is an effective pixel area of the imaging element 33, and a subject image projected in this range is output as a captured image. The elastic member 450 is disposed so as to surround the imaging field 33a and abuts on the infrared cut filter 410, and as shown in FIG. 9, the center of the elastic member 450 is disposed above the center of the imaging field 33a. Note that the term “upper and lower” in the present specification means the vertical direction in the state in which the digital single-lens reflex camera is normally used (the horizontal position shown in FIGS. 1 and 2), and is the arrow direction in FIG.

  As shown in FIG. 8, the piezoelectric elements 430a and 430b are fixed to the end of the infrared cut filter 410 with an adhesive or the like. In the present embodiment, a total of two piezoelectric elements 430 a and 430 b having the same shape are fixed to the left and right ends of the infrared cut filter 410. The piezoelectric elements 430 a and 430 b have a plate shape that extends vertically at the end of the infrared cut filter 410.

  FIG. 10 is a diagram for explaining the piezoelectric element 430. As shown in FIG. 10, an electrode such as silver is provided on the B surface of the piezoelectric element 430 by printing or the like. The electrode on the B surface includes a + phase for exciting the infrared cut filter 410 with bending vibration, It is divided into G phase. In addition, electrodes are provided on substantially the entire C surface of the piezoelectric element 430. The electrodes on the C surface are electrically connected to the G phase on the B surface by a conductive material (not shown), and are kept at the same potential. Be drunk. A conductive connecting member such as a flexible print (not shown) is fixed to the B surface of the piezoelectric element 430 by adhesion or the like, and a predetermined voltage can be independently applied to the + phase and the G phase. . The C surface of the piezoelectric element 430 is fixed to the infrared cut filter 410 by bonding or the like, and the piezoelectric element 430 and the infrared cut filter 410 are configured to move integrally.

  Next, with reference to FIGS. 11 and 12, the mechanism and the vibration shape of the infrared cut filter 410 will be described. FIG. 11 is a side view showing a vibration shape when the infrared cut filter 410 vibrates in a mode having 20 nodes. FIG. 12 is a side view showing a vibration shape when the infrared cut filter 410 vibrates in a mode having 19 nodes.

  First, deformation of the piezoelectric elements 430a and 430b and the infrared cut filter 410 when a positive voltage is applied to the + phase of each of the piezoelectric elements 430a and 430b through the conductive connecting member and each G phase is set to the ground (0 V). explain.

  When the voltage described above is applied, the + phase of the piezoelectric elements 430a and 430b contracts in the perpendicular direction and extends in the in-plane direction. Therefore, the joint surface of the infrared cut filter 410 with the piezoelectric elements 430a and 430b receives a force from the piezoelectric elements 430a and 430b to expand the joint surface in the surface direction so that the joint surface side with the piezoelectric elements 430a and 430b becomes convex. Make any deformations. Therefore, when the voltage described above is applied to the + phase of each of the piezoelectric elements 430a and 430b, the infrared cut filter 410 is bent and deformed as indicated by the solid line in FIG.

  Similarly, when a negative voltage is applied to the + phase, the piezoelectric elements 430a and 430b are deformed in the opposite directions of expansion and contraction, and the infrared cut filter 410 is bent and deformed as shown by a two-dot chain line in FIG.

  Next, a positive voltage is applied to the + phase of the piezoelectric element 430a and a negative voltage is applied to the + phase of the piezoelectric element 430b through the conductive connecting member, and each G phase is set to the ground (0 V). A modification of 430b and the infrared cut filter 410 will be described.

  When the voltage described above is applied, the joint surface between the piezoelectric element 430a and the infrared cut filter 410 is deformed by a mechanism similar to that described above, and the joint surface between the piezoelectric element 430b and the infrared cut filter 410 is deformed. Deforms to become concave. Therefore, when the voltage described above is applied to each + phase of the piezoelectric elements 430a and 430b, the infrared cut filter 410 is bent and deformed as indicated by the solid line in FIG.

  Similarly, when a negative voltage is applied to the + phase of the piezoelectric element 430a and a positive voltage is applied to the + phase of the 430b, the piezoelectric elements 430a and 430b are deformed in the opposite direction of expansion and contraction, and the infrared cut filter 410 has the configuration shown in FIG. Bending deformation as shown by the two-dot chain line occurs.

  In other words, when the voltage applied to the + phase of each of the piezoelectric elements 430a and 430b is periodically switched between positive and negative while the potential of the B-phase electrode is maintained at the ground, the bending so that the unevenness of the infrared cut filter 410 is periodically switched. Vibration occurs. In bending vibration, as shown in FIGS. 11 and 12, vibration nodes (for example, d1, d2, D1, D2) in which the amplitude of vibration becomes substantially zero appear.

  If the periodic voltages applied to the + phase of each of the piezoelectric elements 430a and 430b are the same phase, bending vibration having a shape in which an even number of vibration nodes appear as shown in FIG. In addition, if the periodic voltage applied to the + phase of each of the piezoelectric elements 430a and 430b is shifted by a half wavelength and the phase is reversed, bending vibration having an odd number of vibration nodes as shown in FIG. .

  By setting the frequency of the periodic voltage in the vicinity of the resonance frequency of the natural mode of the infrared cut filter 410, a large amplitude can be obtained with a smaller voltage. The resonance frequency of the eigenmode of the infrared cut filter 410 varies depending on the shape, plate thickness, material, etc. of the infrared cut filter 410, but the eigenmode is selected so that the resonance frequency is outside the audible range so as not to generate unpleasant sound. It is preferable.

  In this embodiment, the mode in which 20 nodes appear and the mode in which 19 nodes appear are described as examples. However, the present invention is not limited to this, and other vibrations may be generated. Alternatively, three or more types of vibration modes may be used.

  Next, an operation for removing foreign matters such as dust attached to the surface of the infrared cut filter 410 in the present embodiment will be described. When the cleaning instruction operation member 44 is operated, the camera body 1 is shifted to the cleaning mode in response to the instruction to start the cleaning mode. In the present embodiment, the cleaning instruction operation member 44 is provided, but the present invention is not limited to this. For example, the cleaning instruction operation member 44 is not limited to a mechanical button, but may be an instruction using a cursor key, an instruction button, or the like on a menu screen displayed on the color liquid crystal monitor 19.

  Further, the transition to the cleaning mode may be performed automatically during a normal camera sequence such as when the power is turned on, or may be performed based on the number of times of shooting, the date, and the like. .

  The power supply circuit 110 supplies power necessary for the cleaning mode to each part of the camera body 1 as necessary. 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 receiving the drive signal from the MPU 100, the piezoelectric element drive circuit 111 generates a periodic voltage that excites bending vibration of the infrared cut filter 410 and applies it to the piezoelectric element 430. The piezoelectric element 430 expands and contracts according to the applied voltage, and the infrared cut filter 410 performs bending vibration.

  FIG. 13 shows the relative positional relationship between the vertical amplitude distribution of the infrared cut filter 410 and the center of the imaging field of view, and the attachment position of the foreign matter. As shown in FIG. 13, at the location where the infrared cut filter 410 contacts the elastic member 450, vibration is inhibited by the elastic member 450 and the amplitude is reduced. In the present embodiment, as described above, the center of the elastic member 450 is disposed above the center of the imaging field of view 33a (see FIG. 13). Therefore, the upper amplitude with respect to the center of the imaging visual field 33a is larger than the lower amplitude. Specifically, the amplitude is the smallest near the upper and lower elastic members, and the largest near the middle (that is, near the center of the elastic member 450).

  Next, the behavior of the foreign matter attached to the surface of the infrared cut filter 410 when the infrared cut filter 410 undergoes the bending vibration described above will be described according to the initial position where the foreign matter is attached. As shown in FIG. 13, the foreign matter adhering to the upper side with respect to the center of the imaging visual field 33a is taken as foreign matter a, and the foreign matter adhering to the lower side is taken as foreign matter b.

  When the infrared cut filter 410 vibrates, the foreign matter is peeled off from the infrared cut filter 410 by acceleration and scattered forward. At that time, the foreign matter adhering to the portion having a large amplitude has a large acceleration and is scattered far from the infrared cut filter 410. On the other hand, the foreign matter adhering to the portion having a small amplitude does not scatter far away because the applied acceleration is small, and falls by gravity near the infrared cut filter 410. When the foreign matter freely falls in the vicinity of the infrared cut filter 410, it is affected by the fluctuation of the fall due to the asymmetry of the foreign matter shape, the minute convection in the vicinity of the infrared cut filter 410, the posture of the imaging device, and the like. As a result, the foreign object may reattach to the surface of the infrared cut filter 410 by touching the infrared cut filter 410 during the fall.

  In the example of FIG. 13, the foreign substance a adheres to a portion having a large amplitude, and thus can be removed without being scattered again and reattaching to the surface of the infrared cut filter 410.

  On the other hand, the foreign substance b does not fly far because it adheres to a portion having a small amplitude. However, the adhesion position of the foreign substance b has a short distance to the lower end of the imaging visual field 33a (close to the lower end), and can move out of the imaging visual field in a shorter time.

  In other words, by disposing the center of the elastic member 450 above the center of the imaging field of view 33a, it is possible to reduce the possibility that a foreign object that has once left the infrared cut filter 410 will be reattached within the imaging field of view, and is more stable. It is possible to provide removal performance. In addition, since it takes a short time for a foreign object that does not fly far to fall out of the field of view while falling freely due to gravity, even if the vibration time for removing the foreign object is shortened, the removed foreign object can be reattached. Can be reduced. In other words, the vibration time for removing the foreign matter can be shortened, and the power required for removing the foreign matter can be reduced. Further, by using the fall due to gravity, it is not necessary to increase the overall amplitude, and the probability that the infrared cut filter 410 is damaged due to the large amplitude can be reduced.

  In the present embodiment, the vibration of the infrared cut filter 410 having a rectangular shape has been described as an example. However, the present invention is not limited to this, and the amplitude near the center of the plate, such as a circular plate, tends to increase. Applicable to plate members.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. Below, it demonstrates centering around difference with 1st Embodiment, the same code | symbol is attached | subjected to the component demonstrated in 1st Embodiment, and the detailed description is abbreviate | omitted.

  FIG. 14 shows a relative positional relationship between the piezoelectric element 430 and the imaging visual field 33a. The imaging visual field 33a is indicated by oblique lines. As shown in FIG. 14, the center of the piezoelectric element 430 is disposed on the upper side with respect to the center of the imaging field of view 33a.

  FIG. 15 shows the relative positional relationship between the vertical amplitude distribution of the infrared cut filter 410 and the center of the imaging field of view, and the attachment position of the foreign matter. Since the piezoelectric element 430 is a vibration drive source, the amplitude of the portion where the piezoelectric element 430 is attached is larger than the amplitude of the portion where the piezoelectric element 430 is not attached. As shown in FIG. 14, when the piezoelectric element 430 is attached to the upper side, the lower part of the infrared cut filter 410 that is not attached becomes a mass that prevents vibration and becomes a damping factor. Accordingly, there is a difference in amplitude even at the portion where the piezoelectric element 430 is adhered, and the attenuation rate increases (the amplitude decreases) toward the lower side as shown in FIG. In the present embodiment, as described above, the center of the piezoelectric element 430 is disposed above the center of the imaging field of view 33a (see FIG. 14). Therefore, the upper amplitude with respect to the center of the imaging visual field 33a is larger than the lower amplitude.

  Next, the behavior of the foreign matter attached to the surface of the infrared cut filter 410 when the infrared cut filter 410 undergoes the bending vibration described above will be described according to the initial position where the foreign matter is attached. As shown in FIG. 15, the foreign matter adhering to the upper side with respect to the center of the imaging visual field 33a is taken as foreign matter a, and the foreign matter adhering to the lower side is taken as foreign matter b.

  In the example of FIG. 15, the foreign substance a adheres to a portion having a large amplitude, and thus can be removed without being scattered again and reattaching to the surface of the infrared cut filter 410.

  On the other hand, the foreign substance b does not fly far because it adheres to a portion having a small amplitude. However, the adhesion position of the foreign substance b has a short distance to the lower end of the imaging visual field 33a (close to the lower end), and can move out of the imaging visual field in a shorter time.

  In other words, by disposing the center of the piezoelectric element 430 above the center of the imaging field of view 33a, it is possible to reduce the possibility that a foreign object that has once left the infrared cut filter 410 will be reattached in the imaging field of view, thereby making it more stable. It is possible to provide removal performance. In addition, since it takes a short time for a foreign object that does not fly far to fall out of the field of view while falling freely due to gravity, even if the vibration time for removing the foreign object is shortened, the removed foreign object can be reattached. Can be reduced. In other words, the vibration time for removing the foreign matter can be shortened, and the power required for removing the foreign matter can be reduced. Further, by using the fall due to gravity, it is not necessary to increase the overall amplitude, and the probability that the infrared cut filter 410 is damaged due to the large amplitude can be reduced.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. Below, it demonstrates centering around difference with 1st Embodiment, the same code | symbol is attached | subjected to the component demonstrated in 1st Embodiment, and the detailed description is abbreviate | omitted.

  FIG. 16 shows a relative positional relationship between the infrared cut filter 410 and the imaging visual field 33a. The imaging visual field 33a is indicated by oblique lines. As shown in FIG. 16, the center of the infrared cut filter 410 is arranged on the upper side with respect to the center of the imaging field of view 33a.

  FIG. 17 shows the vertical amplitude distribution of the infrared cut filter 410 alone. As shown in FIG. 17, apart from the above-described relationship between the antinodes and nodes of the periodic vibration, the natural vibration of the single plate tends to be larger near the center of the plate than the end of the plate. It is generally known from mode analysis and the like.

  FIG. 18 shows the relative position relationship between the amplitude distribution in the vertical direction of the infrared cut filter 410 and the center of the imaging field of view, and the attachment position of the foreign matter. In the present embodiment, as described above, the center of the infrared cut filter 410 is arranged vertically above the center of the imaging field of view 33a (see FIG. 16). Therefore, the upper amplitude with respect to the center of the imaging visual field 33a is larger than the lower amplitude.

  Next, the behavior of the foreign matter attached to the surface of the infrared cut filter 410 when the infrared cut filter 410 undergoes the bending vibration described above will be described according to the initial position where the foreign matter is attached. As shown in FIG. 18, a foreign substance adhering to the upper side with respect to the center of the infrared cut filter 410 is defined as a foreign substance a. Further, a foreign substance adhering to the vicinity of the center in the vertical direction of the infrared cut filter 410 is defined as a foreign substance b. Further, the foreign matter adhering to the lower side with respect to the center of the infrared cut filter 410 is defined as a foreign matter c.

  In the example of FIG. 18, the foreign object a is attached to a portion having a small amplitude, and therefore does not fly far away. However, as described with reference to FIG. 18, since the center of the infrared cut filter 410 is arranged above the center of the imaging field of view 33a, the center of the infrared cut filter 410 is generally matched with the center of the imaging field of view. Compared with the configuration of FIG. 5, the adhesion position of the foreign substance a is far from the upper end of the imaging visual field 33a. Therefore, there is a higher possibility of reattaching to the surface of the infrared cut filter 410 before entering the imaging field 33a.

  Since the foreign matter b adheres to a portion having a large amplitude, the foreign matter b can be removed without scattering again and reattaching to the surface of the infrared cut filter 410.

  Since the foreign material c is attached to a portion having a small amplitude, it does not fly far away. However, as compared with the normal configuration in which the center of the infrared cut filter 410 coincides with the center of the imaging field of view, the attachment position of the foreign substance c has a short distance to the lower end of the imaging field of view 33a and moves out of the imaging field of view in a shorter time. Is possible.

  That is, by disposing the center of the infrared cut filter 410 on the upper side of the center of the imaging field of view 33a, it is possible to reduce the possibility that a foreign object that has once left the infrared cut filter 410 will be reattached in the imaging field of view. The removal performance can be provided. In addition, since it takes a short time for a foreign object that does not fly far to fall out of the field of view while falling freely due to gravity, even if the vibration time for removing the foreign object is shortened, the removed foreign object can be reattached. Can be reduced. In other words, the vibration time for removing the foreign matter can be shortened, and the power required for removing the foreign matter can be reduced. Further, by using the fall due to gravity, it is not necessary to increase the overall amplitude, and the probability that the infrared cut filter 410 is damaged due to the large amplitude can be reduced.

  As mentioned above, although this invention was demonstrated with various embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention. For example, in the above embodiment, the infrared cut filter 410 is configured to excite bending vibration, but the optical member referred to in the present invention is not limited to the infrared cut filter 410. A filter having a substantially rectangular shape and modulating an incident light beam into a desired light beam, for example, an optical low-pass filter or a birefringent plate formed by bonding a birefringent plate, a phase plate and an infrared cut filter 410 The phase plate alone may be configured to excite bending vibration.

  In the above embodiment, the optical apparatus to which the present invention is applied has been described by taking the imaging apparatus using the imaging element 33 as the projection member as an example. However, the present invention is not limited to this, and a liquid crystal projector using a screen as the projection member is used. There may be.

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 which concerns on embodiment of this invention. 1 is a block diagram showing an electrical configuration of a digital single-lens reflex camera according to an embodiment of the present invention. It is a disassembled perspective view which shows schematic structure inside the camera for demonstrating the periphery structure of an imaging unit. It is a disassembled perspective view which shows the structure of an imaging unit. It is sectional drawing which follows the AA line of FIG. It is a perspective view of a vibration unit. It is a perspective view of a vibration unit. It is a schematic diagram which shows the relative positional relationship of the elastic member in 1st Embodiment, and an imaging visual field. It is a figure for demonstrating a piezoelectric element. It is a side view showing a vibration shape when an infrared cut filter vibrates in a mode having 20 nodes. It is a side view which shows a vibration shape when an infrared cut filter vibrates in the mode with 19 nodes. It is a figure which shows the relative positional relationship of the amplitude distribution of the perpendicular direction of the infrared cut filter in 1st Embodiment, and the imaging visual field center, and the adhesion position of a foreign material. It is a schematic diagram which shows the relative positional relationship of the piezoelectric element and imaging visual field in 2nd Embodiment. It is a figure which shows the relative positional relationship of the amplitude distribution of the perpendicular direction of the infrared cut filter in 2nd Embodiment, and the imaging visual field center, and the adhesion position of a foreign material. It is a schematic diagram which shows the relative positional relationship of the infrared cut filter and imaging visual field in 3rd Embodiment. It is a figure which shows the amplitude distribution of the perpendicular direction in the infrared cut filter single-piece | unit in 3rd Embodiment. It is a figure which shows the relative positional relationship of the amplitude distribution of the perpendicular direction of the infrared cut filter in 3rd Embodiment, and the imaging visual field center, and the adhesion position of a foreign material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera main body 2 Mount part 33 Image pick-up element 33a Imaging visual field 400 Imaging unit 410 Infrared cut filter 430 Piezoelectric element 450 Elastic member 460 Energizing member 470 Vibration unit 500 Imaging element unit

Claims (6)

A projection member on which an optical image is formed;
An optical member disposed in front of the projection member;
A vibration member that vibrates the optical member;
The optical device is characterized in that the vibration of the optical member has an upper amplitude larger than a lower amplitude with respect to the center of the visual field of the projection member. An elastic member disposed so as to surround the visual field of the projection member and abutting against the optical member;
The optical apparatus according to claim 1, wherein the center of the elastic member is arranged above the center of the visual field of the projection target member. The vibration member is provided in a form extending vertically on at least one of the left and right ends of the optical member,
The optical apparatus according to claim 1, wherein a center of the vibration member is disposed above a field center of the projection target member.   The optical apparatus according to claim 1, wherein the center of the optical member is disposed above the center of the field of view of the projection target member.   The optical device according to claim 1, wherein the optical member is an optical member that modulates and emits an incident light beam.   The optical device according to claim 5, wherein the optical member is an infrared cut filter.

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