JP2009267536A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove solid or wet foreign matters attached to the surface of an optical member to catch them without fail. <P>SOLUTION: When an AC voltage with a predetermined frequency is applied to a comb shape electrode 405, respective portions close to the surface of an optical low-pass filter 401 are elliptically moved, to excite surface acoustic wave 410. When a foreign matter 411a exists on the surface of the optical low-pass filter 401, the foreign matter 411a is conveyed in the opposite direction of the advance direction (an arrow X in the figure) of the surface acoustic wave 410 by friction force to be generated by the elliptic movement of the surface acoustic wave 410, and caught by an absorption member 408. On the other hand, when a wet foreign matter 411b exists on the surface of the optical low-pass filter 401, the foreign matter 411b is conveyed in the advance direction (an arrow X in the figure) of the surface acoustic wave 410 by the radiation pressure of the surface acoustic wave 410, and caught by a water absorption member 409. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging apparatus having a function of removing foreign matters attached to the surface of an optical member disposed on an optical axis.

  In an imaging device 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 (C-MOS). 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 on the subject side of the imaging element. In this case, if foreign matter such as dust adheres to the cover glass of the image sensor or the surface of these filters, the attached portion becomes a black dot and appears in the photographed image, and the appearance of the image is degraded.

  In particular, in a digital single-lens reflex camera with interchangeable lenses, mechanical operation parts such as a shutter and a quick return mirror are arranged in the vicinity of the image sensor, and foreign matters such as dust generated from these operation parts are covered with the cover glass of the image sensor. Or may adhere to the surface of the filter. 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.

  Further, in addition to the solid foreign matter such as dust described above, condensation may occur due to a sudden change in the usage environment, and moisture generated by the condensation may adhere to the cover glass of the image sensor or the surface of the filter.

  Patent Document 1 discloses that a dustproof optical member disposed between an optical system and an image pickup element is vibrated by a vibration means to generate a bending traveling wave in the dustproof optical member and adhere to the surface of the dustproof member. An electronic imaging device that removes dust and the like is disclosed.

  Further, Patent Document 2 discloses that a dustproof screen that transmits a photographic light flux is provided on the subject side of the image sensor, and further a dust receiving portion is provided on the peripheral edge thereof. By vibrating the dust screen with the piezoelectric element, foreign matter such as dust adhering to the surface of the dust screen is shaken off and collected by the dust receiving portion.

JP 2004-032191 A JP 2003-338968 A

  However, when traveling waves are generated as described in Patent Document 1, the transport direction by traveling waves differs between solid and moisture. The trajectory of the elliptical motion of the traveling wave depicts a direction opposite to the traveling direction of the traveling wave. The solid is conveyed in the direction opposite to the traveling direction of the traveling wave by the frictional force generated at the contact point with the traveling wave. On the other hand, the frictional force is not generated at the contact point, and the moisture is transported in the traveling direction by the radiation pressure of the traveling wave.

  In the technique described in Patent Document 1, since the collecting material is not provided in the conveying direction of the foreign matter due to the bending traveling wave, the foreign matter is scattered and cannot be reliably collected.

  Further, in Patent Document 2, since the foreign matter adhering to the surface of the dustproof curtain is shaken off in the direction of gravity, solids such as dust and moisture fall into the same dust receiver. In this case, the dust receiving portion provided with the adhesive cannot reliably collect moisture. Moreover, there exists a possibility that the adhesive force of an adhesive may fall when a water | moisture content falls. As a result, there is a possibility that foreign matters that have not been collected may reattach to the surface of the dust screen and appear in the photographed image. Further, it may be attached to internal components such as a shutter or a circuit board in the digital single-lens reflex camera body, causing a malfunction in the operation.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to remove solid and moisture foreign substances adhering to the surface of an optical member and to collect them reliably.

  An image pickup apparatus according to the present invention includes an image pickup element that converts an optical image of a subject into an electrical signal, an optical member that is disposed closer to the subject than the image pickup element, a vibration unit that generates a traveling wave in the optical member, A water-absorbing member and an adsorbing member disposed on the surface of the optical member so as to face each other with the imaging region interposed therebetween, and the water-absorbing member is disposed on the traveling direction side of the traveling wave generated by the vibrating means; Is arranged on the opposite side of the traveling direction of the traveling wave generated by the vibrating means.

  According to the present invention, it is possible to remove solids and moisture foreign matters adhering to the surface of the optical member and collect them reliably. Therefore, it is possible to prevent the foreign matter removed from the surface of the optical member from adhering to the optical member again or from adhering to other internal components.

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 so that not only electrical communication but also optical communication, voice communication, and the like are possible. 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 in the direction of the pentaprism 22 (see FIG. 3), and the imaging element 33c (see FIG. 3). In order to guide in the direction, it can be held in 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. When the cleaning instruction operation member 44 is operated, a cleaning mode in which the user directly cleans the optical low-pass filter 401 is started.

  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 sense circuit 105, and a photometric circuit 106. In addition, an LCD drive circuit 107, a battery check circuit 108, a time measurement circuit 109, a power supply circuit 110, a comb electrode drive circuit 111, and a dew condensation sensor 113 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 33c. 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 pentaprism 22 and transmits a part thereof while being held at an angle of 45 ° with respect to the photographic optical axis 50 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 pentaprism 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 pentaprism 22 guides part of the photographic light flux to the photometric sensor 46. The photometric circuit 106 obtains the output of the photometric sensor 46, 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.

  The imaging unit 350 is a unit in which the optical low-pass filter 401, the optical filter 402, the imaging element 33c, the comb electrode 405, and the like are combined with other components to be described later. The detailed configuration will be described later.

  The optical low-pass filter 401 is composed of a transmissive piezoelectric member, and has a filter characteristic that cooperates with the optical filter 402 to restrict the passage of high spatial frequency components. The optical filter 402 has a filter characteristic that restricts the passage of the frequency component so that an unnecessarily high spatial frequency component does not enter the image sensor 33c. The optical filter 402 includes, for example, a birefringent plate such as crystal and an infrared ray. A cut filter is laminated.

  The image sensor 33c converts the optical image of the 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, and any type of imaging device may be adopted.

  Although described in detail later, the comb electrode 405 is provided on the surface of the optical low-pass filter 401, is driven by the comb-shaped electrode drive circuit 111 in response to an instruction from the MPU 100, and is a surface that travels to the optical low-pass filter 401. An elastic wave is excited (excited). In this embodiment, the comb-shaped electrode 405 corresponds to the vibration means referred to in the present invention.

  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 33c 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 of the release button 7. The switch SW2 (7b) is turned on by the second stroke 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 cleaning instruction operation member 44 receives the instruction to start the cleaning mode from the user and shifts the camera body 1 to the cleaning mode state. 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 transition to the cleaning mode is not limited to a mechanical button, but may be an instruction from a menu displayed on the color liquid crystal monitor 19 using a cursor key or an instruction button. good.

  A cleaning number detecting circuit 45 is connected to the cleaning instruction operation member 44, and when the cleaning mode is started, it is detected as the number of cleaning times. The cleaning number detection circuit 45 transmits the detected cleaning number information to the MPU 100.

  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 unit 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.

  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 supply unit 42 is detected, and the result is transmitted to the MPU 100. Upon receiving the cleaning mode start signal, the MPU 100 drives the mirror 6 to a position where the imaging light beam is retracted via the mirror driving circuit 101, and simultaneously drives the sub mirror 30 to a position where it is retracted from the imaging light beam. Further, the MPU 100 drives the focal plane shutter of the shutter unit 32 to a position where it is retracted from the photographing light flux through the shutter drive circuit 103. In this cleaning mode, the user can directly clean the foreign matter on the optical low-pass filter 401 using a cotton swab, sylbon paper, rubber or the like.

  The comb electrode driving circuit 111 applies an AC voltage having a predetermined frequency to the comb electrode 405 in accordance with an instruction from the MPU 100 and causes the optical low-pass filter 401 to excite a surface acoustic wave.

  The dew condensation sensor 113 is composed of, for example, comb-shaped electrodes, and when dew condensation occurs, the comb-teeth electrodes become conductive, and the occurrence of dew condensation is detected on the surface of the optical low-pass filter 401. The dew condensation sensor 113 performs dew condensation check according to the signal from the MPU 100 and transmits the detection output to the MPU 100. In this embodiment, the dew condensation sensor 113 is provided. However, the dew condensation detection means referred to in the present invention is not limited to this, and a dew condition is determined by providing a temperature sensor and a humidity sensor in the camera body 1. It may be.

  Next, a detailed configuration of the imaging unit 350 will be described with reference to FIGS. FIG. 4 is an exploded perspective view showing a schematic configuration inside the camera for explaining the peripheral structure of the imaging unit 350. 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, and the imaging unit 350 is arranged on the photographer side. The imaging unit 350 is adjusted and fixed so that the imaging surface of the imaging element 33c is parallel to a predetermined distance and parallel to the mounting surface of the mount 2 serving as a reference to which the photographic lens unit is attached.

  FIG. 5 is an exploded perspective view showing the configuration of the imaging unit 350. The imaging unit 350 includes a vibration unit 400 and an imaging element unit 500.

  The imaging element unit 500 includes an imaging unit 33 and an imaging unit holding member 510, a circuit board 520 arranged on the back side of the imaging unit 33, an optical filter 402 and an optical filter holding member 404 arranged on the subject side of the imaging unit 33, The vibration unit holding member 403 is included.

  In the imaging unit 33, the imaging element 33c is accommodated in the package member 33b and is protected by the cover glass 33a (see FIG. 6). The imaging unit holding member 510 is made of, for example, metal and is provided with a screw hole 510a. The circuit board 520 is mounted with an image pickup electric circuit, and is provided with a screw escape hole 520a. The escape hole 520a is used to lock the image pickup unit holding member 510 with a screw. The optical filter holding member 404 is fixed to the cover glass 33a of the imaging unit 33 with an adhesive, and the optical filter 402 is fixed and held by a double-sided tape on the optical filter holding member 404. The vibration unit holding member 403 has a frame shape, is positioned at the edge of the optical filter 402, and is fixedly held by a double-sided tape on the optical filter holding member 404.

  The vibration unit 400 includes an optical low-pass filter 401 corresponding to the optical member in the present invention and a comb-shaped electrode 405, and the back surface (the surface on the image sensor 33 c side) of the optical low-pass filter 401 is on the vibration unit holding member 403. It is fixed and held by double-sided tape.

  6 is a cross-sectional view taken along line YY of FIG. The surface on the subject side of the optical filter holding member 404 is in contact with the optical filter 402, and the surface on the photographer side is in contact with the cover glass 33 a of the imaging unit 33. Double-sided tape is fixed to the subject side and the photographer side of the optical filter holding member 404, and the optical filter 402 is fixedly held on the cover glass 33 a of the imaging unit 33 by the double-sided tape of the optical filter holding member 404. Thus, the optical filter 402 and the cover glass 33a of the imaging unit 33 are sealed by the optical filter holding member 404, and a sealed space is formed to prevent entry of foreign matter.

  Further, the subject side surface of the vibration unit holding member 403 is in contact with the optical low-pass filter 401, and the photographer side surface is in contact with the optical filter 402. A double-sided tape is fixed to the subject side of the vibration unit holding member 403, and the optical low-pass filter 401 is fixedly held on the cover glass 33 a of the imaging unit 33 by the double-sided tape of the optical filter holding member 404. Thereby, the space between the optical low-pass filter 401 and the optical filter 402 is sealed by the vibration unit holding member 403, and similarly, a sealed space that prevents entry of foreign matter is formed.

  Since the optical low-pass filter 401 is not held on the subject side, the surface acoustic wave excited on the surface (subject side surface) is difficult to attenuate.

  FIG. 7 is a plan view showing a detailed configuration of the vibration unit 400. The vibration unit 400 includes a rectangular optical low-pass filter 401, a comb electrode 405, an insulating protective film 406, a vibration absorbing member 407, an adsorbing member 408, and a water absorbing member 409.

On the surface of the optical low-pass filter 401, a comb-shaped electrode 405 is provided on the side of one short side (side) of the imaging region E. The comb-shaped electrode 405 includes two sets of electrodes 405a and 405b, and electrode portions having different polarities are alternately arranged at regular intervals in parallel with the side of the imaging region E. The comb-shaped electrode 405 is applied with an AC voltage having a predetermined frequency from the comb-shaped electrode driving circuit 111 in response to an instruction from the MPU 100, and excites a surface acoustic wave traveling in the direction of arrow X in the figure to the optical low-pass filter 401. Let me. An insulating protective film 406 is formed so as to cover the entire surface of the comb-shaped electrode 405. The insulating protective film 406 is formed by vapor deposition or sputtering from at least one of SiO ₂ , Si ₃ N 4, TiN, SiC, etc., and protects the comb-shaped electrode 405 from conductive foreign matter and moisture. Yes.

  Further, on the surface of the optical low-pass filter 401, a vibration absorbing member 407 is provided on the side of the other short side of the imaging region E, in other words, facing the comb-shaped electrode 405 across the imaging region E. That is, the vibration absorbing member 407 is disposed on the traveling direction (arrow X in the figure) of the surface acoustic wave generated by the comb-shaped electrode 405. The vibration absorbing member 407 absorbs the surface acoustic wave and converts it into heat, suppresses the generation of the reflected surface acoustic wave, and prevents the traveling surface acoustic wave from becoming a stationary wave due to the reflected wave. In the present embodiment, the vibration absorbing member 407 corresponds to the suppressing member in the present invention, but is not limited thereto. For example, a comb-shaped electrode is formed instead of the vibration absorbing member 407, and surface acoustic waves are excited by the comb-shaped electrode, or the water absorbing member 409 is fixed to the optical low-pass filter 401 using an adhesive serving as a damping material. Thus, it is possible to suppress the generation of the reflected wave described above.

  Furthermore, an adsorption member 408 is provided on the surface of the optical low-pass filter 401 adjacent to the comb-shaped electrode 405 and outside the comb-shaped electrode 405 (on the end side of the optical low-pass filter 401). That is, the adsorbing member 408 is disposed on the side opposite to the traveling direction of the surface acoustic wave generated by the comb-shaped electrode 405 (arrow X in the figure). The adsorption member 408 is disposed on the insulating protective film 406 in order to reduce the insertion loss of the surface acoustic wave into the imaging region E. The adsorbing member 408 is made of a rubber-based, silicone-based, urethane-based adhesive tape, and collects solid foreign matters such as dust conveyed by the surface acoustic wave excited by the optical low-pass filter 401.

  Furthermore, a water absorbing member 409 is provided on the surface of the optical low-pass filter 401 adjacent to the vibration absorbing member 407 and on the inner side (photographing region E side) than the vibration absorbing member 407. That is, the water absorbing member 409 is disposed on the traveling direction of the surface acoustic wave generated by the comb electrode 405 (arrow X in the figure). The water absorbing member 409 is made of a foamed material such as polystyrene or urethane, a water absorbing sheet, a non-woven fabric, or the like, and collects foreign substances of water conveyed by the surface acoustic wave excited by the optical low-pass filter 401.

  Next, with reference to FIG. 8, the foreign substance removal operation by the vibration unit 400 will be described. FIG. 8 is a schematic diagram for explaining a foreign matter removing operation when an alternating voltage is applied to the comb-shaped electrode 405. When an alternating voltage having a predetermined frequency is applied to the comb-shaped electrode 405, each part in the vicinity of the surface of the optical low-pass filter 401 moves elliptically, and thereby the surface acoustic wave 410 is excited. The surface acoustic wave 410 travels from the comb-shaped electrode 405 toward the vibration absorbing member 407 as indicated by an arrow X.

  When solid foreign matter 411a is present on the surface of the optical low-pass filter 401, the foreign matter 411a moves in the direction opposite to the traveling direction of the surface acoustic wave 410 (arrow X in the figure) due to the frictional force generated by the elliptical motion of the surface acoustic wave 410. Be transported. As a result, the solid foreign material 411 a conveyed by the surface acoustic wave 410 passes over the insulating protective film 406 and is collected by the adsorption member 408.

  On the other hand, when the foreign substance 411b of moisture exists on the surface of the optical low-pass filter 401, the foreign substance 411b is conveyed in the traveling direction of the surface acoustic wave 410 (arrow X in the figure) by the radiation pressure of the surface acoustic wave 410. As a result, the moisture foreign material 411 b conveyed by the surface acoustic wave 410 is collected by the water absorbing member 409.

  FIG. 9 is a flowchart showing the procedure of the foreign substance removal operation process executed by the MPU 100. First, in step S101, when the main switch 43 provided in the camera body 1 is pressed, the MPU 100 turns on the camera body 1 and activates the camera body 1. Next, in step S102, the MPU 100 performs an initial procedure when starting up the camera. This initial procedure includes confirmation of abnormality of the power supply voltage level and SW system provided in the camera body 1, confirmation of the presence / absence of a recording medium, confirmation of lens attachment, and initial setting for photographing.

  Next, in step 103, the MPU 100 executes a foreign matter removal process described later to remove foreign matters attached to the surface of the optical low-pass filter 401 of the imaging unit 350. In this case, solid foreign matters such as dust that float on the camera main body 1 and adhere to the surface of the optical low-pass filter 401 are removed mainly by attaching and detaching the photographing lens unit.

  Next, in step S <b> 104, the MPU 100 starts a timer that is a measurement interval of the dew condensation sensor 113 by the time measurement circuit 109. In step S105, it is determined whether the timer started by the time measuring circuit 109 has passed a predetermined time. If the predetermined time has elapsed, the process proceeds to step S106, and if the predetermined time has not elapsed, the process proceeds to step S108. The predetermined time here is preferably set to, for example, 1 to 15 minutes, assuming a time for moving from a shooting operation in one environment to a shooting operation in another environment.

  In step S106, the MPU 100 controls the condensation sensor 113 to determine whether or not condensation has occurred. If dew condensation is generated as a result of this determination, the process proceeds to step S107, and foreign matter removal processing described later is executed to remove foreign matter attached to the surface of the optical low-pass filter 401 of the imaging unit 350, and the process returns to step S104. . In this case, moisture attached to the surface of the optical low-pass filter 401 is mainly removed. If condensation has not occurred, the process returns to step S104.

  On the other hand, in step S108, the MPU 100 receives 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, and performs camera operations. . The camera operation is a generally known mode for taking and setting a camera, and a detailed description thereof is omitted here.

  In step S109, the MPU 100 determines whether the power is turned off by the main switch 43 when the camera body 1 is in a standby state. If the power is off, the process proceeds to step S110. If not, the process returns to step S105. In step S110, the MPU 100 performs control for terminating each circuit, stores necessary information or the like in the EEPROM 100a, and performs a power-off operation for controlling the power supply circuit 110 to cut off power supply to each circuit. .

  Next, the foreign matter removal process in this embodiment will be described. When proceeding to the foreign substance removal processing (steps S103 and S107), the MPU 100 outputs a control signal instructing the start of application of the AC voltage to the comb electrode driving circuit 111. The comb electrode driving circuit 111 starts applying an alternating voltage having a predetermined frequency to the comb electrode 405 on the optical low-pass filter 401 based on the control signal. Thereby, a surface acoustic wave is excited in the optical low-pass filter 401. The application of the AC voltage is repeated periodically over a predetermined time, for example. By this surface acoustic wave, the foreign matter adhering to the surface of the optical low-pass filter 401 is conveyed and collected by the adsorbing member 408 and the water absorbing member 409. That is, the foreign matter adhering to the surface of the optical low-pass filter 401 is removed from the imaging region E.

  Next, after a predetermined time elapses, the MPU 100 outputs a control signal instructing to stop the application of the AC voltage to the comb electrode drive circuit 111. The comb electrode drive circuit 111 stops the application of the AC voltage to the comb electrode 405 based on the control signal. Thereby, the foreign substance removal process is completed.

  As described above, the surface acoustic wave 410 is excited in the optical low-pass filter 401, and the water-absorbing member 409 and the suction member 408 are disposed so as to face the surface of the optical low-pass filter 401 with the imaging region E interposed therebetween. The solid and moisture foreign matter adhering to the surface of the optical low-pass filter 401 can be removed and reliably collected. Therefore, even if dust that intrudes when the photographing lens unit is replaced or wear powder generated when the shutter unit 32 is driven or the like adheres to the surface of the optical low-pass filter 401, the dust is transported and the adsorption member 408 is conveyed. It is possible to collect reliably. Further, even if condensation occurs due to a sudden change in the use environment and the moisture generated by the condensation adheres to the surface of the optical low-pass filter 401, the moisture can be transported and reliably collected by the water absorbing member 409. Is possible. As a result, it is possible to obtain an image with good image quality that is always free of the shadow of foreign matter.

  In the present embodiment, the foreign substance removal process is executed when the camera body 1 is activated and when condensation is detected. However, the present invention is not limited to this. For example, the imaging apparatus may be configured to execute the foreign substance removal process during a user operation or a cleaning mode in which cleaning is performed directly using liquid.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. Below, it demonstrates centering around difference with the said 1st Embodiment.

  FIG. 10 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 component similar to 1st Embodiment, and the description is abbreviate | omitted. Reference numeral 421 denotes a rectangular infrared cut filter that removes a high spatial frequency. A piezoelectric element 422 is provided in the infrared cut filter 421, which will be described in detail later. The piezoelectric element 422 is driven by the piezoelectric element drive circuit 114 in response to an instruction from the MPU 100, and transmits a bending wave, which is a traveling wave, to the optical low-pass filter 401. Excited. In the present embodiment, the piezoelectric element 422 corresponds to the vibration means referred to in the present invention. A piezoelectric element driving circuit 114 applies an alternating voltage of a predetermined frequency to the piezoelectric element 422 in accordance with an instruction from the MPU 100 and excites the bending wave in the infrared cut filter 421.

  FIG. 11 is an exploded perspective view showing the configuration of the imaging unit 350. The imaging unit 350 includes a vibration unit 420 and an imaging element unit 500 ′.

  The imaging element unit 500 ′ includes an imaging unit 33 and an imaging unit holding member 510, a circuit board 520 arranged on the back side of the imaging unit 33, an optical filter 402 arranged on the subject side of the imaging unit 33, and an optical filter holding member 404. The elastic member 430 is included.

  As described in the first embodiment, the imaging unit holding member 510 is formed of, for example, metal, and is further provided with left and right screw holes 510b in addition to the screw holes 510a. The elastic member 430 is formed in a frame shape with a soft material such as rubber, has a role as a vibration absorbing portion of the infrared cut filter 421, and forms a sealed space between the infrared cut filter 421 and the optical filter 402. The elastic member 430 is preferably composed of a thick member or a member having low hardness in order to increase the vibration absorption of the infrared cut filter 421.

  The vibration unit 420 includes an infrared cut filter 421, a piezoelectric element 422, and a holding member 423 corresponding to the optical member in the present invention. The holding member 423 is formed as a single part from a material having elasticity such as metal, and is provided with a screw escape hole 423a. The holding surface 423b of the holding member 423 is fixed to the vicinity of the four corners of the infrared cut filter 421 by adhesion or the like. The piezoelectric element 422 is fixed to the upper end portion of the surface of the infrared cut filter 421 on the imaging element 33 side by bonding or the like. The vibration unit 420 uses a screw escape hole 423a and a screw hole 510b of the imaging unit holding member 510, and is locked to the imaging element unit 500 ′ with a screw with the elastic member 430 interposed therebetween.

  FIG. 12 is a rear view showing a detailed configuration of the vibration unit 420. The piezoelectric element 422 disposed along the upper end of the infrared cut filter 421 is divided into an a phase and a b phase in the horizontal direction and further divided in the vertical direction. Each area is alternately polarized in the direction of the optical axis (indicated by + and −), and when an AC voltage is applied, the area expands and contracts in the direction perpendicular to the optical axis. Here, the a-phase and the b-phase are shifted in polarization area by a wavelength of / 4, where the + and-polarization areas are one wavelength. When an AC voltage having a phase shift of 90 ° is applied to the a phase and the b phase of the piezoelectric element 422 from the piezoelectric element driving circuit 114 that has received an instruction from the MPU 100, a bending wave is excited in the infrared cut filter 421. Is done.

  Further, similarly to the optical low-pass filter 401 of the first embodiment, a water absorbing member 409 and an adsorbing member 408 are arranged on the surface of the infrared cut filter 421 so as to face each other with the imaging region interposed therebetween. Further, a vibration absorbing member 407 is disposed on the traveling direction side of the bending wave generated by the piezoelectric element 422.

  Next, the foreign substance removal operation by the vibration unit 420 will be described with reference to FIG. FIG. 13 is a schematic diagram for explaining a foreign matter removing operation when an AC voltage is applied to the piezoelectric element 422. When an AC voltage is applied to the a phase and the b phase of the piezoelectric element 422, the bending wave 412 is excited. The bending wave 412 travels toward the vibration absorbing member 407 as indicated by an arrow X.

  When solid foreign matter 411a exists on the surface of the infrared cut filter 421, the foreign matter 411a is conveyed in the direction opposite to the traveling direction of the bending wave 412 (arrow X in the figure) by the frictional force generated by the elliptical motion of the bending wave 412. The As a result, the solid foreign material 411 a conveyed by the bending wave 412 is collected by the adsorption member 408.

  On the other hand, when the moisture foreign matter 411b exists on the surface of the infrared cut filter 421, the foreign matter 411b is conveyed in the traveling direction of the bending wave 412 (arrow X in the figure) by the radiation pressure of the bending wave 412. As a result, the foreign substance 411 b of moisture conveyed by the bending wave 412 is collected by the water absorbing member 409.

  As described above, in the second embodiment as well, as in the first embodiment, the infrared cut filter 421 is caused to excite the bending wave 412 and the infrared cut filter 421 is opposed to the imaging region therebetween. By disposing the water absorbing member 409 and the adsorbing member 408, solid and moisture foreign matter adhering to the surface of the infrared cut filter 421 can be removed, and the trap can be reliably collected.

  In the above embodiment, the bending wave is excited in the infrared cut filter 421. However, an optical low-pass filter, a birefringent plate, or a single phase plate formed by bonding a birefringent plate, a phase plate, and an infrared cut filter. Alternatively, the bending wave may be excited.

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. It is a block diagram which shows the electric constitution of the digital single-lens reflex camera which concerns on 1st Embodiment. It is a disassembled perspective view which shows schematic structure inside the camera for demonstrating the periphery structure of the imaging unit in 1st Embodiment. It is a disassembled perspective view which shows the structure of the imaging unit in 1st Embodiment. It is sectional drawing which follows the YY line | wire of FIG. It is a top view which shows the detailed structure of the vibration unit in 1st Embodiment. It is a schematic diagram for demonstrating the foreign material removal operation | movement by the vibration unit in 1st Embodiment. It is a flowchart which shows the procedure of the foreign material removal operation | movement process performed by MPU in 1st Embodiment. It is a block diagram which shows the electric constitution of the digital single-lens reflex camera which concerns on 2nd Embodiment. It is a disassembled perspective view which shows the structure of the imaging unit in 2nd Embodiment. It is a rear view which shows the detailed structure of the vibration unit in 2nd Embodiment. It is a schematic diagram for demonstrating the foreign material removal operation | movement by the vibration unit in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera body 2 Mount 5 Mirror box 19 Color liquid crystal monitor 32 Shutter unit 33c Image sensor 100 Microcomputer 111 Comb electrode drive circuit 113 Condensation sensor 114 Piezoelectric element drive circuit 300 Main body chassis 350 Imaging unit 400 Vibration unit 401 Optical low-pass filter 402 Optical Filter 405 Comb electrode 406 Insulating protective film 407 Vibration absorbing member 408 Adsorbing member 409 Water absorbing member 420 Vibration unit 422 Piezoelectric element 500 Imaging element unit 500 ′ Imaging element unit 510 Imaging section holding member

Claims (8)

An image sensor that converts an optical image of a subject into an electrical signal;
An optical member disposed closer to the subject than the image sensor;
Vibration means for generating a traveling wave in the optical member;
A water-absorbing member and an adsorbing member arranged to face the surface of the optical member across the imaging region;
The image pickup apparatus, wherein the water absorbing member is disposed on a traveling direction side of a traveling wave generated by the vibration unit, and the adsorption member is disposed on a side opposite to a traveling direction of a traveling wave generated by the vibration unit.   The imaging apparatus according to claim 1, wherein the vibration unit is a comb-shaped electrode, and generates an elastic wave in the optical member.   The imaging apparatus according to claim 2, wherein an insulating protective film is formed to cover the comb electrode.   The said comb-shaped electrode and the said adsorption member are arrange | positioned adjacently, and the said adsorption member is arrange | positioned rather than the said comb-shaped electrode at the edge part side of the said optical member, The Claim 2 or 3 characterized by the above-mentioned. The imaging device described.   The imaging apparatus according to claim 1, wherein the vibration unit is a piezoelectric element and generates a bending wave in the optical member.   The imaging apparatus according to claim 1, further comprising condensation detection means for detecting occurrence of condensation on a surface of the optical member.   On the surface of the optical member, a suppressing member that suppresses the generation of the reflected wave of the traveling wave is disposed outside the imaging region and on the traveling direction side of the traveling wave generated by the vibrating means. The imaging apparatus according to any one of claims 1 to 6, wherein the imaging apparatus is characterized.   The imaging apparatus according to claim 1, wherein a holding member that holds the optical member is disposed on the imaging element side of the optical member.

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