JP4759637B2 - Vibrating device and imaging device using the same - Google Patents

Description

  The present invention provides an image forming apparatus such as an image pickup apparatus including an image pickup element that obtains an image signal corresponding to light irradiated on its own photoelectric conversion surface, and an image projection apparatus including a display element that displays an image projected on a screen. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image device including an element, and a vibration device that vibrates a dustproof member disposed on the front surface of an image forming element in such an image device.

  In recent years, image quality has been remarkably improved in an imaging apparatus using an image forming element, such as an imaging apparatus using an imaging element or an image projection apparatus using a display element such as a liquid crystal. For this reason, dust adheres to the surface of the image forming element such as the imaging element or the display element or the surface of the transparent member (optical element) located in front of the image forming element, thereby causing the image to generate a shadow of dust. However, it is a big problem.

  For example, the photographic optical system is configured to be detachable from the camera body, and a plurality of types of shooting can be performed in a single camera body by arbitrarily attaching and detaching and replacing the desired photographic optical system when the user desires. A so-called “lens interchangeable” type digital camera configured so that an optical system can be selectively used is generally put into practical use. In such a digital camera with interchangeable lenses, dust floating in the surrounding environment where the camera is placed when the photographic optical system is removed from the camera body enters the camera body, or inside the camera body. For example, since various mechanically operated mechanisms such as a shutter / aperture mechanism are arranged, dust and the like are generated during the operation from these various mechanisms, and the lens located on the surface of the image sensor or on the front surface thereof. Or dust may adhere to the surface of a transparent member (optical element) such as a cover glass.

  In addition, a projector for enlarging and projecting an image displayed on a display device such as a CRT or a liquid crystal on a screen using a light source and a projection optical system and viewing the image has been put into practical use. In some cases, dust adheres to the surface of the display element or the surface of a transparent member (optical element) such as a lens or cover glass located in front of the display element, and the shadow of the dust is projected on the screen. It was.

  In view of this, various mechanisms have been developed for removing dust adhering to the surface of an image forming element inside such an image device and the surface of a transparent member (optical element) such as a lens or cover glass located in front of the image forming element.

  For example, in Patent Document 1, a transparent disk-shaped glass plate (dust-proof member) is arranged on the front surface of an image forming element as a unit with the image forming element, and along the outer peripheral portion of the disk-shaped glass plate. A bending traveling wave traveling in the circumferential direction of a disk-shaped glass plate by fixing a pair of annular plate-shaped piezoelectric elements (vibration members) and applying a frequency voltage of a predetermined frequency to each piezoelectric element. An electronic imaging device having a dust removal mechanism for removing dust adhering to a disk-shaped glass plate is disclosed. This Patent Document 1 discloses a method in which a circular piezoelectric body is fixed to a disk-shaped glass plate concentrically as a method for generating a traveling wave in the radial direction of the disk glass plate.

  Further, in Patent Document 2, a piezoelectric element is provided on each of opposite sides of a rectangular plate-shaped dustproof member, and the piezoelectric element is caused to vibrate at a predetermined frequency to resonate the dustproof member. Discloses a camera equipped with a dust removal mechanism that removes dust attached to a rectangular plate-shaped dustproof member in a vibration mode in which a traveling wave of bending is generated. In the vibration mode as disclosed in Patent Document 2, the dust-proof member to which the piezoelectric element as the vibration member is fixed vibrates with the same amplitude over the entire surface.

JP 2004-32191 A JP 2002-204379 A

  In a configuration in which a pair of annular plate-shaped piezoelectric elements (vibration members) are fixed along the outer peripheral portion of a disk-shaped glass plate (dust-proof member) as disclosed in Patent Literature 1, Since the amplitude of the center of the glass plate is small, the dust at the center cannot be removed. Moreover, although the vibration amplitude is larger toward the outer peripheral portion of the disk-shaped glass plate, the disk-shaped glass plate is supported at this position, so that the vibration is attenuated by the support.

  In addition, in a configuration in which a ring-shaped piezoelectric body is concentrically fixed to a disk-shaped glass plate, the magnitude of the waves generated by each piezoelectric body without the size of the pair of piezoelectric bodies being the same shape. Does not match, so traveling waves cannot be created efficiently. Furthermore, the outer periphery of the disk-shaped glass plate vibrates greatly as in the case of a configuration in which a set of annular plate-shaped piezoelectric elements are fixed along the outer periphery of the disk-shaped glass plate. The disk-shaped glass plate cannot be supported without vibration attenuation.

  In Patent Document 2, a large vibration amplitude can be obtained even at the periphery of the dustproof member. However, if the periphery of the dustproof member is supported, the vibration is attenuated and a sufficient vibration amplitude cannot be obtained.

  The present invention has been made in view of the above points, and within a traveling range of traveling waves generated in a non-circular dustproof member, it is possible to increase the vibration speed of the traveling waves and obtain a sufficient vibration amplitude. It is an object of the present invention to provide a vibration device having a high dust removal capability and an imaging device using such a vibration device.

One aspect of the vibration device of the present invention is:
A dust-proof member that has a plate-like shape as a whole,
A first vibration member provided on the dustproof member and generating a first standing wave vibration in the dustproof member by vibrating alone;
A second vibration member provided on the dustproof member and generating a second standing wave vibration in the dustproof member by vibrating alone;
Comprising
The first vibration member and the second vibration member are the first standing wave vibrations that are generated when the first vibration member and the second vibration member are vibrated. And a traveling wave traveling in one direction by overlapping the second standing wave vibration and a position where a traveling wave having a node region having almost no vibration amplitude on the outer peripheral side of the dustproof member is generated. It is characterized by being arranged in.

In addition, one aspect of the imaging device of the present invention is
An image forming element having an image surface on which an optical image is generated;
A dust-proof member that has a plate shape as a whole, at least a region having a predetermined spread in the radial direction from its own center forms a transparent portion, and this transparent portion is disposed to face the image plane with a predetermined interval. When,
The space portion is sealed on the peripheral side of the image forming element and the dustproof member so as to form a sealed space portion at a portion where both the image forming element and the dustproof member are formed to face each other. A sealing structure configured in
The first standing wave vibration is applied to the dust-proof member by being vibrated alone and disposed at a position on the dust-proof member outside the transmission range through which light for generating an optical image is transmitted on the image plane. A first vibration member to be generated;
The dust-proof member is disposed outside the transmission range and does not overlap the first vibrating member, and generates a second standing wave vibration in the dust-proof member by vibrating alone. A second vibrating member to be made,
Comprising
The first vibration member and the second vibration member are the first standing wave vibrations that are generated when the first vibration member and the second vibration member are vibrated. And a traveling wave traveling in one direction by overlapping the second standing wave vibration and a position where a traveling wave having a node region having almost no vibration amplitude on the outer peripheral side of the dustproof member is generated. It is characterized by being arranged in.

  In this case, the image forming element has a support member for supporting the dust-proof member disposed to face the image surface with the predetermined distance, and the support member is an outer peripheral side of the dust-proof member. If it is arranged in the nodal region having almost no vibration amplitude of the traveling wave, it can be supported without damping the vibration.

  According to the present invention, in a traveling range of traveling waves generated in a non-circular dustproof member, a vibration device having high dust removal capability that increases the vibration speed of the traveling waves and obtains sufficient vibration amplitude. And the imaging device using such a vibration device can be provided.

FIG. 1 is a block diagram schematically showing an example mainly of an electrical system configuration of a digital camera as a first embodiment of an imaging device according to the present invention. FIG. 2 is a vertical side view of the image sensor unit including the dust removing mechanism of the digital camera. FIG. 3 is a front view of the dust removing mechanism as viewed from the lens side. FIG. 4 is an exploded perspective view of a main part constituting the dust removing mechanism. 5A is a front view of the dust-proof filter for explaining the state of vibration generated in the dust-proof filter, and FIG. 5B is a cross-sectional view taken along the line BB in FIG. 5A. (C) is CC sectional view taken on the line of FIG. 5 (A). FIG. 6 is a conceptual diagram of a dustproof filter for explaining traveling waves generated in the dustproof filter. FIGS. 7A to 7C are diagrams showing states in which the traveling wave has advanced one wavelength from the states of FIGS. 5A to 5C, respectively. FIG. 8 is a circuit diagram schematically showing the configuration of the dustproof filter control circuit. FIG. 9 is a time chart for explaining each signal output from each component in the dustproof filter control circuit. FIG. 10 is a flowchart illustrating a procedure of a camera sequence (main routine) performed by Bucom of the digital camera according to the first embodiment. FIG. 11A is a flowchart showing an operation procedure of the subroutine “silent excitation operation” in FIG. 10, and FIGS. 11B to 11D respectively show the subroutine “ It is a figure showing the flowchart showing the operation procedure of "display operation" performed in parallel at each timing of "silent vibration operation". FIG. 12 is a diagram illustrating a waveform of the resonance frequency continuously supplied to the vibration member in the silent vibration operation. FIG. 13 is a diagram for explaining a state of vibration generated in the dustproof filter in the digital camera as the second embodiment of the imaging device of the present invention. FIG. 14 is a flowchart showing an operation procedure of a subroutine “silent vibration operation” in the digital camera as the third embodiment of the imaging device of the present invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[First Embodiment]
An image device of the present invention specifically exemplified below has a dust removing mechanism of an image sensor unit that obtains an image signal by photoelectric conversion. Here, as an example, an electronic camera (hereinafter abbreviated as “camera”) is used. This will be described as an improved technique related to the dust removal function. In particular, in the first embodiment, a single-lens reflex electronic camera (digital camera) with interchangeable lenses will be described with reference to FIGS. 1 to 3. FIG. 1 is a block diagram schematically showing a configuration example mainly of an electrical system of the digital camera as the first embodiment of the image equipment of the present invention. 2 is a vertical side view (a cross-sectional view taken along the line AA in FIG. 3) of the image sensor unit including the dust removal mechanism of the digital camera. FIG. 3 is a front view of the dust removal mechanism as viewed from the lens side. It is.

  First, a system configuration example of the digital camera 10 in the present embodiment will be described with reference to FIG.

  The digital camera 10 includes a body unit 100 as a camera body and a lens unit 200 as an interchangeable lens that is one of accessory devices.

  The lens unit 200 is detachable through a lens mount (not shown) provided on the front surface of the body unit 100. The lens unit 200 is controlled by a lens control microcomputer 201 (hereinafter referred to as “Lucom”). The body unit 100 is controlled by a body control microcomputer (hereinafter referred to as “Bucom”) 101. The Lucom 201 and Bucom 101 are electrically connected to each other via the communication connector 102 in a state where the lens unit 200 is mounted on the body unit 100. As a camera system, the Lucom 201 is configured to operate in cooperation with the Bucom 101 in a dependent manner.

  The lens unit 200 includes a photographing lens 202 and a diaphragm 203. The taking lens 202 is driven by a DC motor (not shown) provided in the lens driving mechanism 204. The diaphragm 203 is driven by a stepping motor (not shown) provided in the diaphragm drive mechanism 205. The Lucom 201 controls each of these motors based on a command from the Bucom 101.

  In the body unit 100, the following components are arranged as shown in the figure. For example, from a single-lens reflex type structural member (penta prism 103, screen 104, quick return mirror 105, eyepiece lens 106, sub mirror 107) as an optical system, a focal plane shutter 108 on the photographing optical axis, and the sub mirror 107 And an AF sensor unit 109 for detecting the defocus amount by receiving the reflected light beam.

  In addition, an AF sensor drive circuit 110 that drives and controls the AF sensor unit 109, a mirror drive mechanism 111 that drives and controls the quick return mirror 105, and a shutter charge mechanism 112 that charges a spring that drives the front curtain and rear curtain of the shutter 108. A shutter control circuit 113 that controls the movement of the front and rear curtains, and a photometric circuit 115 that performs photometric processing based on a photometric sensor 114 that detects the light flux from the pentaprism 103 are provided.

  An imaging unit 116 for photoelectrically converting a subject image that has passed through the optical system described above is provided on the imaging optical axis. The imaging unit 116 is formed by integrating a CCD 117 as an imaging element as an image forming element, an optical low-pass filter (LPF) 118 disposed on the front surface thereof, and a dustproof filter 119 as a dustproof member as a unit. It is. Here, in this embodiment, a transparent glass plate (optical element) having a refractive index different from that of air at least in the transparent portion is used as the dust filter 119. However, the present invention is not limited to the glass plate (optical element), and any member (optical element) that is on the optical path and has light transmittance may be used. For example, instead of a transparent glass plate (optical element), an optical low-pass filter (LPF), an infrared cut filter, a deflection filter, a half mirror, or the like may be used. In this case, the frequency and driving time related to vibration, the installation position of the vibration member (described later), etc. are set to values corresponding to the member. In this example, the CCD 117 is taken as an example of the image pickup device, but, of course, a CMOS or other image pickup device may be used.

  Hereinafter, various materials such as an optical low-pass filter (LPF) can be used for the dust-proof filter 119, which is a dust-proof member, but in this embodiment, a glass plate (optical element) is used. Will be described.

  Two piezoelectric elements 120 a and 120 b are attached to the periphery of the dust filter 119. Each of the piezoelectric elements 120a and 120b has two electrodes. By vibrating the piezoelectric elements 120a and 120b at a predetermined frequency by the dust-proof filter control circuit 121, a predetermined vibration is generated in the dust-proof filter 119, and the filter It is configured to remove dust adhering to the surface. In addition, an image stabilization unit for camera shake correction is added to the imaging unit 116.

  In addition, the digital camera 10 according to the present embodiment includes a CCD interface circuit 122 connected to the CCD 117, a liquid crystal monitor 123, and an image processing controller 126 that performs image processing using an SDRAM 124, a flash ROM 125, or the like that functions as a storage area. The electronic recording display function can be provided together with the electronic imaging function. Here, the recording medium 127 is an external recording medium such as various memory cards or an external HDD, and is mounted so as to be communicable and replaceable with the body unit 100 via a communication connector. Then, image data obtained by photographing is recorded on the recording medium 127. As other storage areas, a nonvolatile memory 128 made of, for example, an EEPROM, which stores predetermined control parameters necessary for camera control, is provided so as to be accessible from the Bucom 101.

  The Bucom 101 is connected with an operation display LCD 129 and an operation display LED 130 for notifying the user of the operation state of the digital camera 10 by display output, a camera operation SW 131, and a strobe control circuit 133 that drives the strobe 132. Has been. Here, the operation display LCD 129 or the operation display LED 130 is provided with a display unit that displays the vibration operation of the dust filter 119 while the dust filter control circuit 121 is operating. The camera operation SW 131 is a switch group including operation buttons necessary for operating the digital camera 10 such as a release SW, a mode change SW, and a power SW. Further, the body unit 100 is provided with a battery 134 as a power source and a power supply circuit 135 that converts the voltage of the battery 134 into a voltage required for each circuit unit constituting the digital camera 10 and supplies the converted voltage. In addition, a voltage detection circuit (not shown) for detecting a voltage change when a current is supplied from an external power source via a jack (not shown) is also provided.

  Each part of the digital camera 10 configured as described above generally operates as follows. First, the image processing controller 126 takes in image data from the CCD 117 by controlling the CCD interface circuit 122 in accordance with an instruction from the Bucom 101. This image data is converted into a video signal by the image processing controller 126 and output and displayed on the liquid crystal monitor 123. The user can confirm the captured image from the display image on the liquid crystal monitor 123.

  The SDRAM 124 is a memory for temporarily storing image data, and is used as a work area when image data is converted. The image data is stored in the recording medium 127 after being converted into JPEG data.

  The mirror driving mechanism 111 is a mechanism for driving the quick return mirror 105 to the up position and the down position. When the quick return mirror 105 is in the down position, the light flux from the photographing lens 202 is on the AF sensor unit 109 side. The light is divided and guided to the pentaprism 103 side. The output from the AF sensor in the AF sensor unit 109 is transmitted to the Bucom 101 via the AF sensor driving circuit 110 and a known distance measurement process is performed. On the other hand, part of the light beam that has passed through the pentaprism 103 is guided to a photometric sensor 114 in the photometric circuit 115, and a known photometric process is performed based on the amount of light detected here.

  Next, the imaging unit 116 including the CCD 117 will be described with reference to FIGS.

  The imaging unit 116 is disposed on the side of the photoelectric conversion surface of the CCD 117 and the CCD 117 as an imaging device that obtains an image signal corresponding to the light that is transmitted through the imaging optical system and irradiated on its own photoelectric conversion surface. An optical LPF 118 that removes a high-frequency component from a subject light beam that is transmitted through the light, a dust-proof filter 119 that is a dust-proof member that is opposed to the front surface of the optical LPF 118 at a predetermined interval, and a peripheral portion of the dust-proof filter 119 And piezoelectric elements 120a and 120b, which are vibration members for applying predetermined vibrations to the dustproof filter 119.

  Here, the CCD chip 136 of the CCD 117 is directly mounted on the flexible substrate 138 disposed on the fixed plate 137, and connection portions 139 a and 139 b extending from both ends of the flexible substrate 138 are provided on the main circuit substrate 140. It is connected to the main circuit board 140 side via the connectors 141a and 141b. The protective glass 142 included in the CCD 117 is fixed on the flexible substrate 138 with a spacer 143 interposed therebetween.

  A filter receiving member 144 made of an elastic member or the like is disposed between the CCD 117 and the optical LPF 118. The filter receiving member 144 is disposed at a position that avoids the effective range of the photoelectric conversion surface at the peripheral edge of the front surface of the CCD 117, and is in contact with the vicinity of the peripheral edge of the optical LPF 118 so that the CCD 117 and the optical LPF 118 It is comprised so that substantially airtightness may be maintained between. A holder 145 that covers the CCD 117 and the optical LPF 118 in an airtight manner is disposed. The holder 145 has a rectangular opening 146 at a substantially central portion around the photographing optical axis, and a step portion 147 having a substantially L-shaped cross section is formed at the inner peripheral edge of the opening 146 on the dustproof filter 119 side. The optical LPF 118 and the CCD 117 are disposed from the rear side of the opening 146. Here, the optical LPF 118 is disposed so that the front side peripheral edge of the optical LPF 118 is in substantially airtight contact with the step portion 147, so that the position of the optical LPF 118 in the photographing optical axis direction is regulated by the step portion 147. The front side is secured from the inside. Note that the airtight state of the CCD 117 and the optical LPF 118 may be at a level that can prevent dust from appearing in the photographed image due to the intrusion of dust and the influence of the dust on the image. It may not be the level to prevent.

  On the other hand, a dustproof filter receiving portion that protrudes to the front side of the step portion 147 around the step portion 147 in order to hold the dustproof filter 119 on the front surface of the optical LPF 118 at a predetermined interval at the peripheral portion on the front side of the holder 145. 148 is formed over the entire circumference. An opening portion of the dustproof filter receiving portion 148 becomes an imaging light beam passage area 149. The dustproof filter 119 formed in a polygonal plate shape (quadrangle in this case) as a whole is pressed by a pressing member 151 made of an elastic body such as a leaf spring having one end fixed to the dustproof filter receiving portion 148 with a screw 150. The dustproof filter receiving portion 148 is supported in the state. Here, a vibration-damping receiving member 152 such as rubber or resin is interposed between the pressing member 151 and the dust-proof filter 119, while the piezoelectric element disposed on the outer peripheral edge on the back side of the dust-proof filter 119. A receiving member 153 having a vibration damping property such as rubber is interposed between the dust-proof filter receiving portion 148 and the dust-proof filter receiving portion 148 at a position substantially symmetrical with respect to the optical axis, and is held so as not to inhibit the vibration of the dust-proof filter 119. is doing. Further, the dust filter 119 is positioned in the Y direction in a plane perpendicular to the optical axis by receiving it through the support member 154 at the Z-direction bent portion of the pressing member 151, while the plane perpendicular to the optical axis is also used. As shown in FIG. 3, the X direction inside is positioned by receiving the support portion 155 provided on the holder 145 via the support member 154. The support member 154 is also made of a vibration-reducing material such as rubber or resin so that the vibration of the dustproof filter 119 is not inhibited. If the receiving members 152 and 153 are arranged in an area position having little vibration amplitude generated in the peripheral portion of the traveling wave vibration of the dustproof filter 119 described later, the vibration of the dustproof filter 119 is hardly obstructed, and high efficiency A simple dust removal mechanism can be configured. Further, a seal 156 having an annular lip portion is installed between the peripheral portion of the dustproof filter 119 and the dustproof filter receiving portion 148, and an airtight state of the space including the opening 146 is ensured. The imaging unit 116 is configured in an airtight structure including the holder 145 formed in a desired size for mounting the CCD 117 in this way. Note that the airtight state of the dustproof filter 119 and the dustproof filter receiving portion 148 may be a level at which dust can be prevented from appearing in the photographed image due to the intrusion of dust and the image being affected by the dust. It does not have to be at a level that completely prevents the intrusion of.

  As described above, the dust filter 119 is supported on the dust filter receiver 148 by the pressing member 151 via the receiving members 152 and 153, but at least the support by the receiving member 153 is supported by the seal 156. You may be allowed to take over.

  Further, the flexible elements 157a and 157b are electrically connected to the ends of the piezoelectric elements 120a and 120b as the vibration members, and predetermined electric signals described later from the dustproof filter control circuit 121 are transmitted to the piezoelectric elements 120a and 120b. 120b is input to generate a predetermined vibration in the piezoelectric elements 120a and 120b. The flexes 157a and 157b are made of resin and copper foil and have flexibility, so that the vibrations of the piezoelectric elements 120a and 120b are hardly attenuated. Further, by providing at a place where the vibration amplitude is small (vibration node position described later), vibration attenuation can be further suppressed. On the other hand, in the case of having a camera shake correction mechanism as described below, the piezoelectric elements 120a and 120b move relative to the body unit 100, so that the dustproof filter control circuit 121 is in a fixed member integral with the body unit 100. In this case, the flexes 157a and 157b are deformed and displaced according to the operation of the camera shake correction mechanism. In this case, the flexible cables 157a and 157b are effective because they are flexible and thin, and are optimal for a camera having a camera shake correction mechanism.

  As described later, the dust separated from the surface of the dust filter 119 falls to the lower side of the body unit 100 due to the inertia of the vibration and the action of gravity. Therefore, in the present embodiment, a holding material 159 formed of an adhesive material, an adhesive tape, or the like is disposed on a base 158 provided in the immediate vicinity of the dustproof filter 119 so that the fallen dust is securely held, and again the dustproof filter. It does not return to the surface of the filter 119. Vibration is generated so as to collect dust directly under the dustproof filter 119, and the holding material 159 is disposed directly under the dustproof filter 119, so that dust is scattered to other mechanisms in the body unit 100, causing problems in other functions. There is also an advantage that there is no.

  Next, the camera shake correction function will be briefly described. As shown in FIG. 1, the camera shake correction mechanism includes an X-axis gyro 160, a Y-axis gyro 161, an image stabilization control circuit 162, an X-axis actuator 163, a Y-axis actuator 164, an X frame 165, and a Y frame 166 (holder 145). ), A frame 167, a position detection sensor 168, and an actuator drive circuit 169, which detects an angular velocity of camera shake around the X axis of the camera and an angular velocity of camera shake around the Y axis of the camera. When the camera shake compensation amount is calculated from the angular velocity signal from the axis gyro 161 by the image stabilization control circuit 162 and the direction of the photographic optical axis is the Z-axis direction, the first orthogonality in the XY plane orthogonal to the photographic optical axis. The CCD 117, which is an image sensor, is displaced and moved so as to compensate for blurring in the X-axis direction that is the first direction and the Y-axis direction that is the second direction. . That is, an X-axis actuator 163 that drives the CCD 117 in the X-axis direction when a predetermined drive signal is input from the actuator drive circuit 169, and a Y-axis actuator 164 that drives the CCD 117 in the Y-axis direction when a predetermined drive signal is input. Used as a drive source, an X frame 165 and a Y frame 166 (holder 145) on which the CCD 117 in the imaging unit 116 is mounted are configured as moving objects that move relative to the frame 167. Here, as the X-axis actuator 163 and the Y-axis actuator 164, a combination of an electromagnetic rotary motor and a screw feed mechanism, a linear electromagnetic motor using a voice coil motor, a linear piezoelectric motor, or the like is used. Note that the position detection sensor 168 detects the positions of the X frame 165 and the Y frame 166, and the image stabilization control circuit 162 exceeds the displacement movable range based on the detection result of the position detection sensor 168. Then, the actuator drive circuit 169 is controlled so that the X-axis actuator 163 and the Y-axis actuator 164 are not driven.

  Here, the dust removing mechanism of the first embodiment will be described in more detail with reference to FIGS. FIG. 4 is an exploded perspective view of the main part (vibrator) constituting the dust removing mechanism, and FIG. 5 is a diagram for explaining the state of vibration generated in the dust filter 119, particularly FIG. Is a front view of the dustproof filter 119, FIG. 5B is a cross-sectional view taken along the line BB of FIG. 5A, and FIG. 5C is a cross-sectional view taken along the line CC of FIG. FIG. 6 is a conceptual diagram (corresponding to FIG. 5B) of the dustproof filter 119 for explaining the traveling wave generated in the dustproof filter 119. FIG. 7 is a diagram showing a state in which the traveling wave has advanced one wavelength from the state of FIG.

  The dustproof filter 119 is made of a glass plate (optical element) having a polygonal plate shape (in this embodiment, a quadrangle) as a whole, and at least a region having a predetermined spread in the radial direction from its own center forms a transparent portion. Yes. The dust filter 119 may have a D shape obtained by cutting a part of a circle into a straight line. And the transparent part of this dustproof filter 119 is opposingly arranged by predetermined | prescribed space | interval at the front side of the optical LPF118 by the attachment means mentioned above. In addition, a piezoelectric element 120a, which is a first vibration member for applying vibration to the dustproof filter 119, is provided on the upper peripheral edge of one surface of the dustproof filter 119 (back side in the present embodiment), for example. They are arranged by means such as sticking with an adhesive. Further, a piezoelectric element 120b as a second vibration member for applying vibration to the dustproof filter 119 is similarly disposed on the lower peripheral edge of the dustproof filter 119 by means such as sticking with an adhesive. It is installed. The vibrator 170 is formed by disposing the piezoelectric elements 120a and 120b on the dustproof filter 119. The vibrator 170 resonates when a predetermined frequency voltage is applied to the piezoelectric elements 120a and 120b, and is shown in FIG. Generates bending vibration.

  As shown in FIG. 4, the piezoelectric elements 120a and 120b have signal electrodes 171a and 171b and a back surface facing the signal electrodes 171a and 171b. The routed signal electrodes 172a and 172b are formed. The flexible electrodes 157a and 157b having the conductive pattern are electrically connected to the signal electrodes 171a and 171b and the signal electrodes 172a and 172b, respectively. Each of the electrodes 171a, 171b, 172a, and 172b is applied with a drive voltage having a predetermined period having a different phase by the dustproof filter control circuit 121 connected via the flexible cables 157a and 157b, thereby providing two dustproof filters 119. The standing wave bending vibration can be generated, and the two standing wave bending vibrations can be overlapped to generate the two-dimensional traveling wave bending vibration shown in FIG. ing. In FIG. 5A, different hatching is given to make it easy to distinguish the area 174 where the neutral surface 173 of the dust filter 119 is convex and the area 175 where the neutral surface 173 is concave.

  In FIG. 5, the dust filter 119 has a traveling wave traveling direction (Y direction) indicated by an arrow 176 that is shorter than the direction orthogonal to the traveling wave traveling direction. With this configuration, even when the traveling wave travels a short distance, vibration amplitude greater than a predetermined value can be generated in the imaging light beam passage area 149, and dust removal efficiency is good. In addition, although the vibration amplitude is small near the vibration node 177, the wavelength λ ′ of the bending vibration in the X direction, that is, λx can be increased. .

  Next, a traveling wave generation method will be described in detail with reference to FIG. FIG. 6 shows a cross section corresponding to FIG.

  If the vibrator 170 is in a state indicated by a solid line at a predetermined time t0 and a bending standing wave indicated by a solid line and a broken line is generated, Y = 0 is set as a reference position in the Y direction and an arbitrary Y direction is set. The vibration z at an arbitrary position y along the Y direction at an arbitrary time t of the mass point Y1 on the surface of the vibrator oscillates at the same phase for each wavelength λy of the bending vibration, and the distance is Y = 2π · y / λy. Can be converted into a phase angle, and the angular velocity ω of vibration and the maximum amplitude A in the Z direction are expressed by the following equation (1).

z = Asin (Y) · cos (ωt) (1)
When a frequency voltage described later is applied only to the piezoelectric element 120a arranged at y = 0, a standing wave of the above equation (1) is generated, and the state at time t = 0 is indicated by a solid line (the broken line indicates t = π / ω state).

  Here, the piezoelectric elements 120a and 120b are polarized in the direction indicated by the arrow 178 in FIG. 6, and the arrangement position of the piezoelectric element 120b (center of the Y direction width of the piezoelectric element) and the arrangement position of the piezoelectric element 120a (the piezoelectric element) The piezoelectric elements 120a and 120b are arranged so that the distance H from the center in the Y-direction width is H = k (λy / 4), where k is an odd number, and the voltage applied to the piezoelectric element 120b is piezoelectric. A voltage whose phase is shifted by π / 2 with respect to the voltage applied to the element 120a is applied. In this state, if the vibration z at an arbitrary position y in the Y direction is the same as the above equation (1), z is as the following equation (2).

z = A · sin (Y) · cos (ωt)
+ A · sin (Y + π / 2) · cos (ωt + π / 2) (2)
The second term of the equation (2) indicates standing wave vibration when the above frequency voltage is applied only to the piezoelectric element 120b. Therefore, this equation (2) means that the standing wave vibration of the piezoelectric element 120a of the first term and the standing wave vibration of the piezoelectric element 120b of the second term are superimposed.

The above equation (2) is
z = A · sin (Y) · cos (ωt)
+ A · sin (Y + π / 2) · cos (ωt + π / 2)
= A · sin (Y) · cos (ωt) −A · cos (Y) · sin (ωt)
= A · sin (Y-ωt)
And can be transformed.

That is, the vibration z in this state is
z = A · sin (Y−ωt) (3)
This equation (3) represents a traveling wave. In this way, two vibrators that independently generate standing wave vibrations are arranged in a positional relationship of H = k (λy / 4), and a voltage having a predetermined frequency whose phase is shifted by π / 2 is applied to each. Then, traveling wave vibration can be generated.

  The traveling direction of the traveling wave in the above equation (3) is the positive direction of the Y direction, and is the direction indicated by the arrow 176 in FIG. At this time, the mass point Y1 on the surface of the dustproof filter 119 causes an elliptical vibration 179 as shown in FIG. In FIG. 6, the dust adhering to the dustproof filter 119 receives an inertial force downward, and the force for separating the dust becomes stronger in combination with the gravity.

  Due to the generation of the traveling wave as described above, as shown in FIG. 7, the area 180 having a large vibration amplitude and the area 181 having almost no vibration amplitude shown in FIG. 5 move upward. Therefore, all the places other than the vibration node 177Y (indicated by a thick broken line) parallel to the Y direction that can be formed in the peripheral portion in the X direction of the dustproof filter 119 are areas 180 having a large vibration amplitude.

  Here, when looking at the vibration in the X direction, it can be seen that a bending standing wave is generated (see FIG. 5C). Assuming that the wavelength of the bending standing wave is λx and the size of the imaging light beam passage area 149 in the X direction is Ex, λx / 2> Ex, and the imaging light beam passage area 149 has a vibration amplitude of the traveling wave. Since it is smaller than the large region, the imaging light beam passage area 149 has sufficient vibration amplitude, and dust removal can be ensured.

  As shown in FIG. 5C, if the length Sx of the piezoelectric elements 120a and 120b in the X direction is set to λx / 2 or less, it becomes an area of the same phase of the bending standing wave vibration (there is no reverse phase). Therefore, vibration can be generated with high efficiency. Of course, as shown in FIG. 3, there is no problem even if it is longer than λx / 2.

  In addition, the vibration node 177Y (shown by a thick broken line) parallel to the Y direction in FIG. 7 becomes a bending standing wave vibration node even if a traveling wave is generated, so this portion is pressed in the Z direction. When held in place, vibrations are not attenuated and can be reliably supported. The node 177Y portion has only a small vibration amplitude in the Z direction, but may have a large amplitude in the X direction and the Y direction. In such a case, since the vibration of the dust-proof filter 119 is not hindered by supporting it through the support member 154 made of a vibration damping member such as rubber, it can be supported efficiently. On the other hand, if the left and right sides of the seal 156 are provided along the node 177Y, there is almost no vibration attenuation, and the upper and lower sides of the seal 156 are in contact with the traveling wave generating portion. Since the lip shape is used to prevent the force from acting strongly in the bending vibration amplitude direction, vibration attenuation by the seal 156 is extremely small.

  The predetermined frequency for vibrating the piezoelectric elements 120a and 120b is determined by the shape, material, and support state of the dustproof filter 119 constituting the vibrator 170. Usually, the temperature is an elastic coefficient of the vibrator 170. This is one of the factors that change the natural frequency. Therefore, it is preferable to measure the temperature during operation and take into account the change in the natural frequency. In this case, a temperature sensor (not shown) connected to a temperature measurement circuit (not shown) is provided in the digital camera 10, and a correction value of the vibration frequency of the vibrator 170 determined in advance from the measured temperature of the temperature sensor. Is stored in the non-volatile memory 128, the measured temperature and the correction value are read into the Bucom 101, and the drive frequency is calculated to obtain the drive frequency of the dustproof filter control circuit 121, thereby generating efficient vibration even with respect to temperature changes. can do.

  A voltage having a predetermined frequency is applied to the piezoelectric elements 120 a and 120 b configured in this manner in the respective plate thickness directions by the dustproof filter control circuit 121. As shown in the above equation (2), the first frequency signal output from the dustproof filter control circuit 121 is applied to the piezoelectric element 120a, and has the same frequency as the first frequency signal, but the phase is π / The second frequency signal shifted by 2 is applied to the piezoelectric element 120b.

  When the frequency signal is applied to the piezoelectric elements 120a and 120b as described above, a traveling wave traveling upward as indicated by an arrow 176 in FIG. When the movement of a point on the surface of the dustproof filter 119 when a traveling wave is generated is observed, the vibration mode has vibration nodes 177Y on both sides of the vibrator 170. In this embodiment, the portion of the joint 177Y is pressed and supported via the members 152 and 153. Since the receiving members 152 and 153 are made of a soft material having vibration damping properties such as rubber, the vibration in the surface direction of the dustproof filter 119 is allowed and the vibration in the pressing direction is suppressed, but the vibration component in the pressing support direction. Since there is almost no node portion, the vibration of the imaging light beam passage area 149 of the dust filter 119 is not attenuated.

  Next, the dustproof filter control circuit 121 of the digital camera 10 in this embodiment will be described below.

  FIG. 8 is a circuit diagram schematically showing the configuration of the dustproof filter control circuit 121 in the body unit 100 of the digital camera 10. FIG. 9 is a time chart showing the form of each signal output from each component in the dustproof filter control circuit 121 of FIG.

  The clock generator 1011 (see FIG. 8) included in the Bucom 101 outputs a pulse signal (basic clock) at a frequency sufficiently faster than the signal frequency to be applied to the piezoelectric elements 120a and 120b (see Sig1 shown in FIG. 9). ). This basic clock signal is input to the N-ary counter 1211 of the dustproof filter control circuit 121.

  The N-ary counter 1211 counts the pulse signal and outputs a count end pulse signal every time it reaches a predetermined value N. That is, the basic clock signal is divided by 1 / N (see Sig2 in FIG. 9).

  Since the high and low duty ratio of the divided pulse signal is not 1: 1, the duty ratio is converted to 1: 1 via the first ½ divider circuit 1212. At this time, the frequency is halved (see Sig3 in FIG. 9). The output signal of the first ½ divider circuit 1212 is output to the second ½ divider circuit 1213 and the exclusive OR (ExOR) circuit 1214.

  The pulse signal input to the second ½ divider circuit 1213 is further output at a half frequency (see Sig 4 in FIG. 9). Here, in the high state of the pulse signal Sig4, the MOS transistor Q01 is turned on. On the other hand, the pulse signal is applied to the MOS transistor Q02 via the first inverter 1215. Therefore, in the low state of this pulse signal, the MOS transistor Q02 is turned on. When the MOS transistors Q01 and Q02 connected to the primary side of the transformer A1216 are alternately turned on, the Sig5 signal shown in FIG. 9 is generated on the secondary side of the transformer A1216. In this case, the winding ratio of the transformer A1216 is determined by the output voltage of the power supply circuit 135 and the voltage required to drive one piezoelectric element 120a. The resistor R00 is provided to restrict an excessive current from flowing through the transformer A1216.

  In driving the piezoelectric element 120a, the MOS transistor Q00 must be in the ON state and a voltage must be applied from the power supply circuit 135 to the center tap of the transformer A1216. In this case, ON / OFF control of the MOS transistor Q00 is performed from the output port P_PwContA of the Bucom 101.

The frequency is calculated by the following equation (4). That is,
fdrv = fpls / 4N (4)
Here, N is a set value for the N-ary counter 1211, fpls is a frequency of an output pulse of the clock generator 1011 and fdrv is a frequency of a signal applied to the piezoelectric element 120a.

  On the other hand, the output signal Sig3 of the first ½ divider circuit 1212 is output to the third ½ divider circuit 1217 via the ExOR circuit 1214. In this case, when the output port P_θCont of the Bucom 101 is in the high state by the ExOR circuit 1214, the pulse signal Sig3 is inverted and output to the third ½ divider circuit 1217, and the output port P_θCont is in the low state. In some cases, the pulse signal Sig3 is output to the third ½ frequency divider 1217 as it is (see Sig6 in FIG. 9). The pulse signal Sig6 is further reduced to a half frequency by the third ½ divider circuit 1217 and then output (see Sig7 in FIG. 9). As a result, the second inverter 1218, the MOS transistor Q11, the MOS transistor Q12, and the transformer B 1219 are driven, and a drive signal (Sig8 in FIG. 9) having a predetermined voltage is output to the piezoelectric element 120b.

  The functions of the second inverter 1218, the MOS transistors Q11 and Q12, the transformer B1219, and the resistor R10 are substantially the same as those of the first inverter 1215, the MOS transistors Q01 and Q02, the transformer A1216, and the resistor R00. Yes.

  In any of the first to third ½ divider circuits 1212, 1213, and 1217, a frequency dividing operation is performed corresponding to the rising edge of the input pulse signal. Even when the frequency of the pulse signal is the same, when the signal is inverted, the second 1/2 divider circuit 1213 and the third 1/2 divider circuit 1217 output the pulse signals respectively. Causes a phase difference. In this case, the phase difference is 90 ° (ie, π / 2).

  Therefore, a phase difference of 90 ° (π / 2) occurs between the signal Sig5 applied to the piezoelectric element 120a and the signal Sig8 applied to the piezoelectric element 120b. This phase difference can be controlled by the output port P_θCont of the Bucom 101. For example, if the output port P_θCont is in a high state, a phase difference of 90 ° (π / 2) is generated, and if it is in a low state, no phase difference is generated. That is, by controlling the output port P_θCont, different forms of vibration can be applied to the dustproof filter 119.

  As described above, when a signal having a phase difference of 90 ° (π / 2) is applied to the piezoelectric elements 120a and 120b, two standing wave bending vibrations of the above equation (2) are given to the dustproof filter 119. Bending traveling wave vibration is generated by superposition of standing wave bending vibration.

  Further, when the digital camera 10 vibrates the dust filter 119 at an ultrasonic frequency (frequency of 20 kHz or higher), an operation display is provided for notifying the operator of the digital camera 10 of the operation of the dust filter 119. LCD 129 or operation display LED 130 is provided. That is, when vibration is applied by the vibrating members (piezoelectric elements 120a and 120b) to the dust-proof member (dust-proof filter 119) that is disposed in front of the CCD 117 and has vibration, the drive circuit for the vibrating member The display unit of the digital camera 10 is operated in conjunction with the operation of the (dust filter control circuit 121), and the operation of the dust filter 119 is also notified (details will be described later).

  In order to explain the above features in detail, the control performed by the Bucom 101 will be described with reference to FIGS. 10 and 11.

  FIG. 10 is a flowchart showing the operation control of the digital camera 10 of the present embodiment, and illustrates the procedure of the camera sequence (main routine) performed by the Bucom 101.

  The control program related to the flowchart shown in FIG. 10 that can be operated by the Bucom 101 starts its operation when the power SW (not shown) of the camera body unit 100 is turned on.

  First, a process for starting the digital camera 10 is executed (step S101). That is, the power supply circuit 135 is controlled to supply power to each circuit unit constituting the digital camera 10. Also, initial setting of each circuit is performed.

  Next, a dust-free filter 119 is vibrated silently (that is, outside the audible range) by calling a subroutine “silent vibration operation” described later (step S102). The audible range referred to here is in the range of about 20 Hz to 20000 Hz with reference to the hearing ability of ordinary people.

  Subsequent steps S103 to S124 are a group of steps executed periodically. That is, first, attachment / detachment of the accessory to / from the digital camera 10 is detected (step S103). This detects, for example, that the lens unit 200 as one of the accessories is attached to the body unit 100. The attachment / detachment detection operation checks the attachment / detachment state of the lens unit 200 by communicating with the Lucom 201.

  If it is detected that a predetermined accessory is attached to the body unit 100 (step S104), the dustproof filter 119 is vibrated silently by calling a subroutine “silent vibration operation” (step S105). .

  As described above, since there is a high possibility of dust adhering to each lens, the dust filter 119, etc., especially during a period when the lens unit 200 as an accessory is not attached to the body unit 100 as the camera body, the lens as described above. It is effective to perform an operation of dusting at the timing when the mounting of the unit 200 is detected. In addition, since it is highly possible that outside air circulates inside the body unit 100 when the lens is replaced and dust enters and adheres, it is meaningful to remove the dust when the lens is replaced. Then, it is regarded as immediately before shooting, and the process proceeds to step S106.

  On the other hand, if it is detected in step S104 that the lens unit 200 has been removed from the body unit 100, the process proceeds to the next step S106.

  In step S106, the state of a predetermined operation switch of the digital camera 10 is detected.

  Here, the 1st. Whether or not a release SW (not shown) has been operated is determined based on the ON / OFF state of the SW (step S107). The state is read and if 1st. If the release SW has not been turned on for a predetermined time or longer, the state of the power supply SW is determined (step S108). If the power SW is turned on, the process returns to step S103.

  On the other hand, in step S107, 1st. When it is determined that the release SW has been turned on, the luminance information of the subject is obtained from the photometry circuit 115, and the exposure time (Tv value) of the imaging unit 116 and the aperture setting value (Av value) of the lens unit 200 are obtained from this information. Is calculated (step S109).

  Thereafter, the detection data of the AF sensor unit 109 is obtained via the AF sensor driving circuit 110, and the amount of focus shift is calculated based on this data (step S110). Then, it is determined whether or not the calculated deviation amount is within the permitted range (step S111). If not, the driving control of the photographing lens 202 is performed (step S112), and the process returns to step S103. .

  On the other hand, if the amount of deviation is within the permitted range, the subroutine “silent excitation operation” is called to start the vibration of the dustproof filter 119 without sound (step S113).

  Furthermore, 2nd. It is determined whether or not a release SW (not shown) has been turned ON (step S114). This 2nd. When the release SW is in the ON state, the process proceeds to the subsequent step S115 to start a predetermined photographing operation (described later in detail), but when it is in the OFF state, the process proceeds to step S108.

  During the imaging operation, as usual, the electronic imaging operation for a time corresponding to a second (exposure time) preset for exposure is controlled.

  As the photographing operation, the subject is imaged in a predetermined order from step S115 to step S121. First, the Av value is transmitted to the Lucom 201 to command the diaphragm 203 to be driven (step S115), and the quick return mirror 105 is moved to the UP position (step S116). Then, the front curtain travel of the shutter 108 is started and OPEN control is performed (step S117), and the execution of the “imaging operation” is commanded to the image processing controller 126 (step S118). When exposure (imaging) to the CCD 117 for the time indicated by the Tv value is completed, the trailing curtain travel of the shutter 108 is started and CLOSE control is performed (step S119). Then, the quick return mirror 105 is driven to the Down position and the shutter 108 is charged (step S120).

  Thereafter, the Lucom 201 is instructed to return the aperture 203 to the open position (step S121), and the series of imaging operations is completed.

  Subsequently, it is detected whether or not the recording medium 127 is attached to the body unit 100 (step S122). If not, a warning is displayed (step S123). And it transfers to said step S103 again and repeats a similar series of processes.

  On the other hand, if the recording medium 127 is attached, the image processing controller 126 is instructed to record the captured image data on the recording medium 127 (step S124). When the image data recording operation is completed, the process proceeds to step S103 again, and a similar series of processes is repeated.

  Hereinafter, with reference to FIG. 11, the control procedure of the “silent excitation operation” subroutine called in the above-described three steps (S102, S105, S113) will be described with respect to the detailed relationship between the vibration form and the sound. The “vibration form” is a form of vibration caused by the piezoelectric elements 120a and 120b, which are vibration members.

  FIG. 11A is a flowchart showing an operation procedure of the subroutine “silent excitation operation”, and FIGS. 11B to 11D respectively show the subroutine “silent excitation vibration” of FIG. 11A. It is a figure showing the flowchart showing the operation procedure of "display operation" performed in parallel at each timing of "work".

  In this silent vibration operation, a graph showing the waveform of the resonance frequency continuously supplied to the vibration member is shown in FIG. The subroutines “silent vibration operation” and “display operation” in FIG. 11 are routines intended for vibration operation only for dust removal of the dust filter 119, and therefore the vibration frequency f 0 is determined by the dust filter 119. It is set to a predetermined frequency near the resonance frequency. For example, in this case, since it is 80 kHz and the vibration is at least 20 kHz or more, it is silent for the user.

  First, data relating to the drive time (Toscf0) and drive frequency (resonance frequency: Noscf0) for vibrating the dust filter 119 is read from the data stored in a predetermined area of the nonvolatile memory 128 (step S201). At this timing, the display of the vibration mode on the display unit provided on the operation display LCD 129 or the operation display LED 130 is turned ON (step S301). Then, it is determined whether a predetermined time has elapsed (step S302). When the predetermined time has not elapsed, the display of the vibration mode is continued, and after the predetermined time has elapsed, the vibration mode display is turned off (step S303). .

  Next, the drive frequency Noscf0 is output from the output port D_NCnt of the Bucom 101 to the N-ary counter 1211 of the dustproof filter control circuit 121 (step S202).

  In subsequent steps S203 to S205, the dust removing operation is performed as follows. That is, first, the dust removing operation is started and executed. On the other hand, the display at this time starts the vibration operation display of the output ports P_PwContA and P_PwContB at the High timing (step S311), and then determines whether or not the predetermined time has passed (step S312), and the predetermined time has passed. If not, the display of the vibration operation is continued, and after the predetermined time has elapsed, the vibration operation display is terminated (step S313). The vibration operation display at this time is a display that changes with time or dust removal (not shown). The predetermined time in this case is substantially equal to Toscf0, which is the duration of the vibration operation described later. Further, when the output ports P_PwContA and P_PwContB are set to High for dust removal (Step S203), the piezoelectric elements 120a and 120b vibrate the dustproof filter 119 at a predetermined driving frequency (Noscf0) and adhere to the surface of the dustproof filter 119. Shake off the dust. When dust adhering to the surface of the dust-proof filter 119 is shaken off by this dust removing operation, air vibrations occur simultaneously and ultrasonic waves are generated. (However, even if it is driven at the drive frequency Noscf0, it does not become a sound within the audible range of ordinary people and cannot be heard).

  Wait for a predetermined drive time (Toscf0) and vibrate the dust filter 119 (step S204), and after the predetermined drive time (Toscf0) has elapsed, set the output ports P_PwContA and P_PwContB to Low to display the vibration end display. Is turned on (step S321), and the dust removing operation is stopped (step S205). The vibration end display is turned off after a predetermined time has elapsed (step S322), and the display ends (step S323). Then, the process returns to the next step after the called step.

  The vibration frequency f0 (resonance frequency (Noscf0)) and driving time (Toscf0) applied in this subroutine show waveforms as shown in the graph of FIG. That is, a constant waveform (f0 = 80 kHz) has a continuous waveform that lasts for a time sufficient for dust removal (Toscf0).

  That is, this vibration form adjusts and controls the resonance frequency supplied to the vibration member.

[Second Embodiment]
FIG. 13 (A) is a front view of the dust filter for explaining the state of vibration generated in the dust filter in the digital camera as the second embodiment of the imaging device of the present invention, and FIG. 13A is a cross-sectional view taken along line BB in FIG. 13A, and FIG. 13C is a cross-sectional view taken along line CC in FIG.

Only differences from the first embodiment (see FIG. 5) will be described below.
The first difference is the installation position of the piezoelectric element 120a as the first vibration member, and the back side (second surface) of the dust filter 119 in which the piezoelectric element 120b as the second vibration member is installed. ) On the front side (first surface) of the dust-proof filter 119 opposite to that of the dust-proof filter 119 and below the dust-proof filter 119 near the installation position of the piezoelectric element 120b. However, the distance H between the center positions of the piezoelectric element 120a and the piezoelectric element 120b is H = k (λ / 4) where k is an odd number (in the example of FIG. 13B, k = 1, and the piezoelectric element 120a). Is provided to face the piezoelectric element 120b).

  The second difference is the shape of the piezoelectric elements 120a and 120b, and the length in the X direction is shorter and the length in the Y direction is longer than that in the first embodiment. The reason for this configuration is that the piezoelectric element 120a and the piezoelectric element 120b can be installed in the Y direction so as to overlap each other. The generation of vibration energy can be made the same as in the first embodiment by increasing the length in the Y direction by the amount corresponding to the decrease in the length in the X direction. As described above, by shifting the imaging light beam passage area 149 in the Y direction, the dimension of the dustproof filter 119 in the Y direction can be further reduced. Further, since the dust-proof filter 119 can be pressed directly on the pressing position of the pressing member, the same pressing member can be used, and the Z-direction dimension is the portion where the piezoelectric element 120a is attached in the first embodiment. Same as, but otherwise it can be made smaller. Further, the lengths of the piezoelectric elements 120a and 120b in the X direction are within λx / 2 when the bending standing wave vibration wavelength is λx, and are in the same phase area of the bending standing wave vibration (in the opposite phase). Therefore, vibration can be generated with high efficiency.

  Of course, the node 177 having almost no vibration amplitude can be formed as in the first embodiment.

[Third Embodiment]
FIG. 14 is a flowchart showing an operation procedure of a subroutine “silent vibration operation” called in a camera sequence (main routine) performed by Bucom in the digital camera as the third embodiment of the image equipment of the present invention. .

  This is a modification of the operation of the subroutine “silent vibration operation” shown in FIG. 11 in the first embodiment. The third embodiment differs from the first embodiment in the operation of the dustproof filter 119. . That is, in the first embodiment, the driving frequency of the dustproof filter 119 is set to a fixed value of f0, and the traveling wave is generated. However, in the third embodiment, the standing wave vibration and the traveling wave vibration are timed. Generate mixed vibration. In the subroutine “silent vibration operation” of FIG. 14, the vibration frequency f0 is set to a predetermined frequency near the resonance frequency of the dust filter 119. For example, in this case, since it is 80 kHz and the vibration is at least 20 kHz or more, it is silent for the user.

  First, data relating to the drive time (Toscf0), drive start frequency (Noscfs), frequency shift amount (Δf), and drive end frequency (Noscft) for vibrating the dustproof filter 119 is stored in a predetermined area of the nonvolatile memory 128. The data is read out (step S211). The display of the vibration mode as shown in FIG. 11B at this timing is the same as in the first embodiment.

  Next, the drive start frequency (Noscfs) is set to the drive frequency (Noscf) (step S212). Further, the drive frequency (Noscf) is output from the output port D_NCnt of the Bucom 101 to the N-ary counter 1211 of the dustproof filter control circuit 121 (step S213).

  In subsequent step S203, the dust removing operation is performed as follows. That is, first, the dust removing operation is started and executed. At this time, the vibration operation display as shown in FIG. 11C is performed in the same manner as in the first embodiment.

  First, when the output port P_PwCont is set to High for dust removal (step S203), the piezoelectric elements 120a and 120b vibrate the dust filter 119 at a predetermined drive frequency (Noscf). At this time, since it is not the resonance frequency, the phase of the vibration generated with respect to the applied frequency signal is shifted, and the dustproof filter 119 generates a traveling vibration mixed with the standing wave vibration. Dust adhering to the surface of the dustproof filter 119 is shaken off by the mixed vibration of the standing wave vibration and the traveling wave vibration, but the vibration amplitude near the node of the standing wave becomes small, and the dust in this area cannot be removed. This vibration is continued during the drive time (Toscf0) (step S204). Next, it is determined whether or not the drive frequency (Noscf) is the drive end frequency (Noscft) (step S214). If they do not match (NO is determined), the frequency shift amount (Δf) is changed to the drive frequency (Noscf). Are added to set the drive frequency (Noscf) again (step S215), and the operations from step S212 to step S204 are repeated.

  When the drive frequency (Noscf) matches the drive end frequency (Noscft) in step S214 (YES), the output port P_PwCont is set to Low, and the excitation operation of the piezoelectric elements 120a and 120b is completed. (Step S205), a series of “silent vibration operation” ends. At this time, the vibration end display as shown in FIG. 11D is performed in the same manner as in the first embodiment.

  When the frequency is changed in this way, as described above, the phase of vibration of the piezoelectric element 120a and the vibration of the piezoelectric element 120b change and the vibration amplitude also changes. Therefore, if the driving start frequency (Noscfs), the frequency shift amount (Δf), and the driving end frequency (Noscft) are set so that the dustproof filter 119 passes the frequency at which traveling wave vibrations are substantially generated, the dustproof filter 119 is fixed. First, a vibration that is a mixture of wave vibration and traveling wave vibration is generated, then the standing wave vibration component gradually decreases and the traveling wave vibration component increases. It is possible to control such that standing wave vibration is increased. It is also possible to shake off dust that remains on the surface of the dustproof filter 119 due to standing wave vibration, or that adheres to the dustproof filter 119 because the vibration amplitude is small, not the resonance frequency.

  Further, if the drive start frequency (Noscfs) and the drive end frequency (Noscft) are widened to some extent, it is possible to absorb changes in the resonance frequency due to the temperature of the vibrator 170 and manufacturing variations, and an extremely simple circuit configuration. It is possible to reliably shake off the dust adhering to the dust filter 119.

  Furthermore, in the above embodiment, the phase difference between the voltages applied to the piezoelectric elements 120a and 120b is π / 2. However, since the traveling wave component is generated unless the phase is in phase, the phase difference is changed to another component. Anyway.

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the gist of the present invention. .

  For example, in addition to the above-described dust removing mechanism using the vibration member, a system that removes dust from the dust-proof filter 119 using an air flow or a mechanism that removes dust from the dust-proof filter 119 using a wiper may be used in combination.

  In the above-described embodiment, the vibration member is a piezoelectric element, but may be an electrostrictive material or a giant magnetostrictive material.

  In addition, for example, an ITO (indium oxide / tin) film, which is a transparent conductive film, an indium zinc film, a polycrystal is formed on the surface so that dust adhering to the target member to be vibrated can be more efficiently shaken off during vibration. A coating treatment may be applied to a 3,4 ethylenedioxythiophene film, a surfactant film which is a hygroscopic antistatic film, a siloxane film, or the like. The frequency and driving time related to the vibration are set to values corresponding to the film member.

  The optical LPF 118 described as one embodiment of the present application may be configured as a plurality of optical LPFs having birefringence. Then, the optical LPF arranged closest to the subject among the plurality of optical LPFs may be used as a dustproof member (vibration target) instead of the dustproof filter 119 described in FIG.

  Moreover, it is set as the camera which does not have the optical LPF118 described in FIG. 2 as one Embodiment of this application, The dustproof filter 119 is used as any optical elements, such as an optical LPF, an infrared cut filter, a deflection filter, a half mirror, for example It may be used.

  Furthermore, not only the optical LPF 118 is not provided, but the dust filter 119 may be replaced with the protective glass 142 shown in FIG. In this case, the dust-proof / moisture-proof state between the protective glass 142 and the CCD chip 136 is maintained, and the dust-proof filter 119 shown in FIG. Can be used. Needless to say, the protective glass 142 may be used as an optical element such as an optical LPF, an infrared cut filter, a deflection filter, or a half mirror.

  Note that the imaging apparatus to which the present invention is applied is not limited to the exemplified imaging device (digital camera), and any device that requires a dust removal function may be used, and can be put into practical use by performing modifications as necessary. . More specifically, the dust removal mechanism of the present invention may be provided between a display element and a light source in an image projection apparatus using a display element such as a liquid crystal or between a display element and a projection lens.

    DESCRIPTION OF SYMBOLS 10 ... Digital camera, 100 ... Body unit, 101 ... Microcomputer (Bucom) for body control, 105 ... Quick return mirror, 107 ... Sub mirror, 108 ... Shutter, 116 ... Imaging unit, 117 ... CCD, 118 ... Optical low-pass filter ( LPF), 119 ... Dust filter, 120a, 120b ... Piezoelectric element, 121 ... Dust filter control circuit, 122 ... CCD interface circuit, 128 ... Non-volatile memory, 129 ... LCD for operation display, 130 ... LED for operation display, 131 ... Camera operation SW 134 ... Battery 135 ... Power supply circuit 136 ... CCD chip 137 ... Fixed plate 138 ... Flexible substrate 139a, 139b ... Connection part 140 ... Main circuit board 141a, 141b ... Kuta, 142 ... Protective glass, 143 ... Spacer, 144 ... Filter receiving member, 145 ... Holder, 146 ... Opening, 147 ... Step part, 148 ... Dustproof filter receiving part, 149 ... Imaging beam passage area, 150 ... Screw, 151 ... Pressing member, 152,153 ... Receiving member, 154 ... Supporting member, 155 ... Supporting part, 156 ... Seal, 157a, 157b ... Flexible, 158 ... Stand, 159 ... Holding material, 166 ... Y frame, 170 ... Oscillator, 171a, 171b, 172a, 172b ... signal electrodes, 173 ... neutral surface, 174 ... neutral surface convex area, 175 ... neutral surface concave area, 176 ... arrow indicating the traveling direction of traveling wave, 177 ... Vibration node, 177Y, vibration node parallel to Y direction, 178, arrow indicating polarization direction, 179, elliptical vibration, 180 Area with large vibration amplitude, 181 ... Area with almost no vibration amplitude, 200 ... Lens unit, 201 ... Microcomputer for lens control (Lucom), 202 ... Shooting lens, 203 ... Aperture, 1011 ... Clock generator, 1211 ... N-ary counter 1212, 1213, 1217, 1/2 frequency divider, 1214, exclusive OR (ExOR) circuit, 1215, 1218, inverter, 1216, transformer A, 1219, transformer B.

Claims (19)

A dust-proof member that has a plate-like shape as a whole,
A first vibration member provided on the dustproof member and generating a first standing wave vibration in the dustproof member by vibrating alone;
A second vibration member provided on the dustproof member and generating a second standing wave vibration in the dustproof member by vibrating alone;
Comprising
The first vibration member and the second vibration member are the first standing wave vibrations that are generated when the first vibration member and the second vibration member are vibrated. And a traveling wave traveling in one direction by overlapping the second standing wave vibration and a position where a traveling wave having a node region having almost no vibration amplitude on the outer peripheral side of the dustproof member is generated. A vibration device characterized by being arranged in   It further has a support member for supporting the dustproof member with respect to an arbitrary device, and the support member is arranged in a node region having almost no vibration amplitude of the traveling wave on the outer peripheral side of the dustproof member. The vibration device according to claim 1, wherein:   2. The vibration device according to claim 1, wherein the first and second vibrating members are substantially rectangular having a long side in a direction orthogonal to a traveling direction of the traveling wave. The first vibration member comprises a first piezoelectric element,
The second vibration member comprises a second piezoelectric element,
When the wavelengths λ and k in the traveling direction of the traveling wave are arbitrary odd numbers, the first piezoelectric element and the second piezoelectric element are provided at positions separated from each other by k · (λ / 4). The vibration device according to claim 3.   5. The vibration device according to claim 4, wherein a frequency signal having a phase difference of π / 2 is applied to the first piezoelectric element and the second piezoelectric element. The dust-proof member is substantially rectangular,
A standing wave of at least wavelength λ ′ is generated in a direction orthogonal to the traveling direction of the traveling wave,
5. The vibration device according to claim 4, wherein the first piezoelectric element and the second piezoelectric element have a substantially rectangular shape having a long side of ½ or less of the wavelength λ ′ of the standing wave. .   The vibration device according to claim 4, wherein the first piezoelectric element and the second piezoelectric element are provided on the same surface of the dust-proof member.   The first piezoelectric element is provided on a first surface of the dust-proof member, and the second piezoelectric element is formed on the second surface opposite to the first surface of the dust-proof member. The vibration device according to claim 4, wherein the vibration device is provided to face the piezoelectric element. An image forming element having an image surface on which an optical image is generated;
A dust-proof member that has a plate shape as a whole, at least a region having a predetermined spread in the radial direction from its own center forms a transparent portion, and this transparent portion is disposed to face the image plane with a predetermined interval. When,
The space portion is sealed on the peripheral side of the image forming element and the dustproof member so as to form a sealed space portion at a portion where both the image forming element and the dustproof member are formed to face each other. A sealing structure configured in
The first standing wave vibration is applied to the dust-proof member by being vibrated alone and disposed at a position on the dust-proof member outside the transmission range through which light for generating an optical image is transmitted on the image plane. A first vibration member to be generated;
The dust-proof member is disposed outside the transmission range and does not overlap the first vibrating member, and generates a second standing wave vibration in the dust-proof member by vibrating alone. A second vibrating member to be made,
Comprising
The first vibration member and the second vibration member are the first standing wave vibrations that are generated when the first vibration member and the second vibration member are vibrated. And a traveling wave traveling in one direction by overlapping the second standing wave vibration and a position where a traveling wave having a node region having almost no vibration amplitude on the outer peripheral side of the dustproof member is generated. An image device characterized by being arranged in   A support member for supporting the dust-proof member disposed to face the image surface of the image-forming element with the predetermined interval, and the support member is located on the outer peripheral side of the dust-proof member. The imaging device according to claim 9, wherein the imaging device is arranged in a node region having almost no vibration amplitude of the traveling wave.   The image apparatus according to claim 10, wherein the first and second vibrating members are substantially rectangular having a long side in a direction orthogonal to a traveling direction of the traveling wave. The first vibration member comprises a first piezoelectric element,
The second vibration member comprises a second piezoelectric element,
When the wavelengths λ and k in the traveling direction of the traveling wave are arbitrary odd numbers, the first piezoelectric element and the second piezoelectric element are provided at positions separated from each other by k · (λ / 4). The imaging device according to claim 11. A standing wave of at least wavelength λ ′ is generated in a direction orthogonal to the traveling direction of the traveling wave,
The imaging device according to claim 12, wherein a width of the light transmission range in a direction perpendicular to the traveling wave is λ '/ 2 or less.   The imaging apparatus according to claim 12, wherein a frequency signal having a phase difference of π / 2 is applied to the first piezoelectric element and the second piezoelectric element. The dust-proof member is substantially rectangular,
A standing wave of at least wavelength λ ′ is generated in a direction orthogonal to the traveling direction of the traveling wave,
13. The imaging apparatus according to claim 12, wherein the first piezoelectric element and the second piezoelectric element are substantially rectangular having a long side that is 1/2 or less of a wavelength λ ′ of the standing wave. .   13. The imaging apparatus according to claim 12, wherein the first piezoelectric element and the second piezoelectric element are provided on the same surface of the dustproof member.   The image apparatus according to claim 16, wherein the first piezoelectric element and the second piezoelectric element are provided at positions sandwiching the light transmission range of the dust-proof member.   The first piezoelectric element is provided on the first surface of the dust-proof member, and the second piezoelectric element is on the second surface opposite to the first surface of the dust-proof member. The imaging device according to claim 12, wherein the imaging device is provided so as to face the element.   19. The image apparatus according to claim 18, wherein the first piezoelectric element and the second piezoelectric element are provided at a position on one side with respect to a transmission range of the light beam of the dustproof member.

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