JP2010161615A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus which can be small-sized with simple configuration in spite of provision of dust-proofing and drip-proofing functions. <P>SOLUTION: The imaging apparatus includes: a case 401 including an opening 101 for guiding subject light to an imaging optical system; a transparent diaphragm 403 provided in the opening; and a vibrating means 404 for vibrating the transparent diaphragm 403. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging apparatus that obtains image data of a subject, and more particularly to an imaging apparatus having a dustproof / dripproof function.

There exists patent document 1 as a wiper apparatus of a television camera housing. The wiper device described in Patent Document 1 is a wiper device that removes water droplets adhering to the front glass of a TV camera housing. A transparent thin-film diaphragm is formed on the effective light transmitting portion of the front glass, It comprises a sonic element. Water droplets adhering to the front glass are scattered by the ultrasonic vibration generated in the transparent thin film diaphragm by the ultrasonic element. Therefore, the reflection of the wiper blade in the image data, which has been a problem in wiping due to the arcuate movement of the wiper blade, can be solved.
JP-A-8-254738

  However, the technique described in Patent Document 1 has a problem that it is difficult to reduce the size of the imaging apparatus because the television camera housing includes the ultrasonic element and the transparent thin film diaphragm. Further, since the transparent thin film diaphragm is disposed on the front surface of the front glass through the air gap and the vibration-proof seal material, there is a problem that the structure becomes complicated. In addition, since there is no specific description about the location and shape of the ultrasonic element, it is not possible to generate efficient vibration.

  An object of the present invention is to solve the above-described problems and to provide an imaging apparatus that can be downsized with a simple configuration while having a dustproof / dripproof function.

  In order to solve the above problems, an imaging apparatus according to the present invention vibrates a casing having an opening for guiding subject light to an imaging optical system, a transparent diaphragm provided in the opening, and the transparent diaphragm. And a vibration means. Since the transparent diaphragm is provided in the opening of the housing and replaces the function of the front glass, it is possible to reduce the size with a simple configuration while having dustproof and dripproof functions.

  Further, the imaging optical system may be a bending optical system. The bending optical system is suitable for use in a harsh environment exposed to dust and water droplets because there is no movable part protruding outside the housing unlike the retractable optical system. Therefore, by applying the present invention to an imaging apparatus in which the imaging optical system is a bending optical system, it is possible to provide an imaging apparatus that can be downsized with a simple configuration while having a dustproof / dripproof function.

  Further, the vibration means may be a piezoelectric element. By using a piezoelectric element widely used in the dustproof device placed in front of the imaging device as the vibration means, an imaging device that has a simple structure and can be downsized with a dustproof and dripproof function It can be provided at low cost.

  The vibration means may be driven in a plurality of frequency bands including a resonance frequency. As a result, the position of the node generated in the transparent diaphragm due to vibration moves, so that dust and water droplets can be removed over the entire surface of the transparent diaphragm.

  Further, the vibration means may be arranged on the periphery of the transparent diaphragm. Thereby, dust and water droplets can be removed over the entire surface of the transparent diaphragm.

  The transparent diaphragm may be substantially rectangular, and the excitation means may be arranged along one side of the transparent diaphragm or a pair of opposite sides. When the transparent diaphragm is substantially square, the vibration means can be arranged along one side of the transparent diaphragm or a pair of opposite sides to efficiently vibrate the transparent diaphragm and The vibration means is low cost.

  As described above, according to the present invention, the transparent diaphragm and the vibration means for vibrating the same are provided at the opening of the housing that guides the subject light to the imaging optical system. It is possible to provide an imaging apparatus that can be downsized with a simple configuration. In addition, since the shape and arrangement of the vibration means are optimized, the cost can be reduced while improving the efficiency of the dustproof / dripproof function.

(Embodiment)
(1. Configuration of digital camera)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an appearance of a digital camera 100 that is an example of an embodiment of the present invention. FIG. 1 (a) shows the front side, and FIG. 1 (b) shows the back side.

  On the front side, an opening 101 that guides subject light to the imaging optical system, a flash 102 that enables photographing in a dark place, and an auxiliary light emitting unit 103 that enables focusing in a dark place are arranged. The opening 101 is provided with a water repellent system (described later). On the upper surface, a power switch 104 and a shutter button 105 are arranged. On the back side, a liquid crystal monitor 106 capable of visually recognizing a subject image and an operation unit 107 for receiving various operations are arranged.

  The user operates the power switch 104 to turn on the digital camera 100, determines the angle of view while looking at the liquid crystal monitor 106, presses the shutter button 105 halfway, and then presses the shutter button 105 fully to select the subject. Image data can be obtained. The digital camera 100 performs a focusing operation when the shutter button 105 is half-pressed, and performs a photographing operation when the shutter button 105 is fully pressed. When shooting in a dark place, the auxiliary light emitting unit 103 emits light when the shutter button 105 is half-pressed to assist the focusing operation, and the flash 102 emits light when the shutter button 105 is fully pressed. Assists shooting operations with proper exposure.

  FIG. 2 is a block diagram showing the configuration of the digital camera 100.

  The digital camera 100 includes a control microcomputer 200 that receives inputs from the power switch 104, the shutter button 105, and the operation unit 107 to control each unit, a video signal processing circuit 250 that processes video signals, and an imaging optical system 300 that forms subject light. It has.

  The control microcomputer 200 is supplied with power from the battery 201 via the power supply circuit 202. The battery check circuit 203 monitors the voltage of the battery 201 and notifies the control microcomputer 200 when a low voltage is detected. The control microcomputer 200 outputs the time information output from the clock circuit 204 to the video signal processing circuit 250.

  The control microcomputer 200 receives inputs from the power switch 104, the shutter button 105, and the operation unit 107 sensed by the switch sense circuit 205, and controls each unit based on commands stored in the built-in EEPROM.

  The control microcomputer 200 controls the flash 102 via the flash circuit 206 and also controls the auxiliary light emitting unit 103 via the auxiliary light emitting unit circuit 207. Further, the water repellent system 400 is driven via the water repellent system driving unit 500. The control microcomputer 200 acquires the position of each lens provided in the imaging optical system 300 via the lens position detection unit 208, and is provided in the imaging optical system 300 via the lens driving unit 209 and the lens driving unit 212. Drive each lens. The lens driving unit 209 drives two zoom lenses (described later) provided in the imaging optical system 300, and the lens driving unit 212 drives a focus lens (described later) provided in the imaging optical system 300. The control microcomputer 200 drives an aperture unit (described later) provided in the imaging optical system 300 via the aperture drive unit 210 and also provides a shutter unit (described later) provided in the imaging optical system 300 via the shutter drive unit 211. Drive.

  The video signal processing circuit 250 controls the image sensor 252 via the timing control unit 251. The image sensor 252 may be a CCD image sensor or a CMOS image sensor. The imaging element 252 outputs an image signal corresponding to the subject light imaged by the imaging optical system 300. The clamp / CDS circuit 253 clamps the image signal output from the image sensor 252 and removes noise by the CDS circuit. The image signal that has been clamped by the clamp / CDS circuit 253 and whose noise has been removed is adjusted in gain by the AGC circuit 254, and then converted into image data that is digital data by the A / D conversion circuit 255, and the video signal processing circuit 250.

The video signal processing circuit 250 performs predetermined signal processing on the image data input from the A / D conversion circuit 255 while using the SDRAM 261 as a work memory. When the user determines the angle of view while viewing the liquid crystal monitor 106, the video signal processing circuit 250 continues to the liquid crystal monitor driving circuit 256 the image data subjected to signal processing suitable for display on the liquid crystal monitor 106. And output. The liquid crystal monitor drive circuit 256 drives the liquid crystal monitor 106 based on the image data output from the video signal processing circuit 250. On the other hand, when the user obtains image data by fully pressing the shutter button 105, the image data subjected to signal processing suitable for recording is output to the buffer memory 257. The memory controller 258 reads the image data from the buffer memory 257 and records the image data on a built-in memory 259 or a memory card (not shown) attached to the external interface 260 based on designation by the operation unit 107.
(2. Configuration of imaging optical system)
FIG. 3 is a cross-sectional view showing the configuration of the imaging optical system 300.

  The opening 101 is provided with a water repellent system 400. The subject light transmitted through the water repellent system 400 is further transmitted through the objective lens 301 and then changed in direction by 90 degrees by the prism 302. That is, the optical axis L-L ′ is changed by 90 degrees to become the optical axis L′-L ″.

The subject light whose direction has been changed by 90 degrees passes through the zoom lens 303, passes through the aperture unit 304 and the shutter unit 305, and further passes through the zoom lens 306, the focus lens 307, and the low-pass filter 308 to reach the image sensor 252. . The zoom lens 303 and the zoom lens 306 move in the direction of the optical axis L′-L ″, respectively, so that an optical image by subject light imaged on the image sensor 252 can be enlarged or reduced. By moving in the direction of the optical axis L′-L ″, the subject light can be focused on the image sensor 252. The aperture unit 304 can adjust the amount of subject light reaching the image sensor 252 by changing the size of the opening. The shutter unit 305 can cause subject light to reach the image sensor 252 only for a predetermined period by opening the opening. The low pass filter 308 is an optical filter for removing high frequency components exceeding the pixel pitch of the image sensor 252.
(3. Structure of water repellent system)
FIG. 4 is a cross-sectional view showing the configuration of the water repellent system 400.

  The water repellent system 400 is configured in an opening 101 provided on the front surface of the digital camera 100. An opening 101 is provided in a housing 401 on the front surface of the digital camera 100. Ribs 401 a are formed on the front side of the housing 401.

  The water repellent system 400 is laminated and formed on the rib 401a in a direction opposite to the front surface of the digital camera 100 (back surface direction). First, the water repellent filter receiving rubber 402 is placed on the rib 401a. Next, the water repellent filter 403 is placed on the water repellent filter receiving rubber 402. A piezoelectric element 404 is attached to the periphery of the water repellent filter 403 with an adhesive or the like. A flexible cable for electrical connection with the water repellent system driving unit 500 is attached to the piezoelectric element 404, but is omitted in FIG. Next, a water repellent filter receiving rubber 405 is placed on the piezoelectric element 404. Finally, the water repellent filter receiving rubber 402, the water repellent filter 403, the piezoelectric element 404, and the water repellent filter receiving rubber 405 are fixed on the rib 401a by the water repellent filter receiving member 406. The water repellent filter receiving rubber 402 and the water repellent filter receiving rubber 405 are configured to prevent dust and water droplets from entering the digital camera 100.

  FIG. 5 is a schematic view of the water repellent system 400 as viewed from the front side of the digital camera 100. FIG. 5A shows a case where the opening 101 is circular, and FIG. 5B shows a case where the opening 101 is rectangular. However, the rib 401a is removed. The opening 101 may be oval as shown in FIG.

  In FIG. 5A, the piezoelectric element 404, the water repellent filter receiving rubber 402, and the optical window 407 can be visually recognized from the outside of the opening 101 in this order. The water repellent filter 403 is transparent and covers the entire opening 101. Both surfaces of the water repellent filter 403 are subjected to antireflection treatment such as AR coating. The piezoelectric element 404 and the water repellent filter receiving rubber 402 are disposed so as to surround the periphery of the water repellent filter 403. The optical window 407 is an opening provided on the back side of the water repellent filter receiving member 406 and on the front side of the objective lens 301. 5A shows the configuration in which the integrated piezoelectric element 404 is disposed so as to surround the water repellent filter 403, the piezoelectric element may not be integrated. That is, a plurality of piezoelectric elements may be arranged so as to surround the periphery of the water repellent filter 403. Since the piezoelectric element 404 formed into a circle is generally expensive in general, the cost can be reduced by arranging a plurality of piezoelectric elements so as to surround the periphery of the water-repellent filter 403.

  The configuration is the same in FIG. 5B, but in FIG. 5B, the piezoelectric element 404 is not arranged so as to surround the water repellent filter 403, but only on the left and right sides of the water repellent filter 403. The difference is arranged. Here, the arrangement of the piezoelectric elements 404 is not limited to this arrangement, and may be arranged only above and below the water repellent filter 403. When the water repellent filter 404 is rectangular, by disposing the piezoelectric element 404 along a pair of opposing sides of the water repellent filter 404, the water repellent filter 403 can be vibrated efficiently and the piezoelectric element 404 can be vibrated. Is low cost. In FIG. 5B, the piezoelectric element 404 is arranged along a pair of opposite sides of the water repellent filter 404, but the piezoelectric element 404 is arranged along one side of the water repellent filter 404. However, the same effect can be obtained.

  In the case where the optical window 407 is rectangular, it is needless to say that the rectangular shape of the opening 101 contributes to cost reduction because the area of the water repellent filter 403 can be reduced.

  Although the circular shape and the rectangular shape have been shown as the shape of the opening 101, the present invention is not limited to these shapes. It may be an opening having another shape such as a polygon. Also, the number of piezoelectric elements may be one or plural.

As described above, since the water repellent system 400 is arranged alone (not on the front surface of the front glass) in the opening 101 provided on the front surface of the digital camera 100, the water repellent system 400 has a dustproof / dripproof function. It is possible to reduce the size and cost with a simple configuration.
(4. Configuration of water repellent system drive unit)
FIG. 6 is a block diagram illustrating a configuration of the water repellent system driving unit 500.

  The clock generation circuit in the control microcomputer 200 outputs a variable frequency clock to the water repellent system drive unit 500. The water repellent system driving unit 500 includes a logic circuit 501, an FET 502, and a transformer 503. The clock output from the control microcomputer 200 passes through the logic circuit 501 and is input to the FET 502. The FET 502 is connected to the primary side of the transformer 503. A voltage having a predetermined frequency is generated on the secondary side of the transformer 503 by the switching operation of the FET 502. A piezoelectric element 404 is connected to the secondary side of the transformer 503. A voltage having a predetermined frequency is applied to the piezoelectric element 404, and vibration corresponding to the predetermined frequency is generated. Since this vibration propagates to the water repellent filter 403, dust and water droplets adhering to the water repellent filter 403 can be removed. The voltage on the primary side of the transformer 503 is about 5V, and the voltage on the secondary side of the transformer 503 is about 100V.

  The water repellent filter 403 vibrates due to the vibration of the piezoelectric element 404. FIG. 7 is a diagram showing a resonance mode when the water repellent filter 403 is circular (in the case of FIG. 5A). When the water repellent filter 403 has another shape such as a rectangle (in the case of FIG. 5B), the resonance modes are different.

  The resonance mode of the water repellent filter 403 varies depending on the frequency of the voltage applied from the water repellent system driving unit 500 to the piezoelectric element 404. When the frequency is increased from a low frequency, the primary resonance shown in FIG. When the frequency is further increased, the secondary resonance shown in FIG. 7 (b) appears, and when the frequency is further increased, the tertiary resonance shown in FIG. 7 (c) appears. Even after this, higher-order resonance appears by increasing the frequency. Dust and water droplets adhering to the water repellent filter 403 can be removed by the vibration of the water repellent filter 403 generated by resonance.

Normally, when dust or water droplets adhere to a position (node) with zero amplitude in resonance, the surface of the water repellent filter 403 is not displaced at this position, so it is difficult to remove the dust or water droplets. Therefore, the clock generation circuit in the control microcomputer 200 generates a plurality of resonance modes in the water repellent filter 403 by sequentially generating clocks having different frequencies or gradually changing (sweeping) the clock frequency. Let Thereby, the position of the node of the water repellent filter 403 moves, so that dust and water droplets can be removed over the entire surface of the water repellent filter 403. Here, the resonance mode to be generated is not limited to the resonance modes shown in FIGS. 7A to 7C.
(5. Correspondence between the present invention and the embodiment)
The opening 101 is an example of the opening of the present invention. The housing 401 is an example of the housing of the present invention. The water repellent filter 403 is an example of the transparent diaphragm of the present invention. Although the name “water repellent filter” is used, it is needless to say that the purpose is not limited to the removal of water droplets but also the purpose of removing dust. The piezoelectric element 404 is an example of the vibration means of the present invention. The digital camera 100 is an example of an imaging apparatus of the present invention. The imaging optical system 300 is an example of the imaging optical system of the present invention.

  According to the present invention, it is possible to provide an imaging apparatus that can be downsized with a simple configuration while having a dustproof / dripproof function, and is therefore useful when applied to a digital camera or a video camera.

The figure which shows the external appearance of the digital camera 100 which is an example of Embodiment of this invention. 1 is a block diagram illustrating a configuration of a digital camera 100 that is an example of an embodiment of the present invention. Sectional drawing which shows the structure of the imaging optical system 300 Sectional drawing which shows the structure of the water repellent system 400 Schematic view of the water repellent system 400 seen from the front side of the digital camera 100 The block diagram which shows the structure of the water repellent system drive part 500 The figure which shows the resonance mode in case the water repellent filter 403 is circular (in the case of Fig.5 (a)).

DESCRIPTION OF SYMBOLS 100 Digital camera 101 Opening part 102 Flash 103 Auxiliary light emission part 104 Power switch 105 Shutter button 106 Liquid crystal monitor 107 Operation part 200 Control microcomputer 201 Battery 202 Power supply circuit 203 Battery check circuit 204 Clock circuit 205 Switch sense circuit 206 Flash circuit 207 Auxiliary Light emitting unit circuit 208 Lens position detection unit 209 Lens driving unit 210 Aperture driving unit 211 Shutter driving unit 212 Lens driving unit 250 Video signal processing circuit 251 Timing control unit 252 Imaging element 253 Clamp / CDS circuit 254 AGC circuit 255 A / D conversion Circuit 256 LCD monitor drive circuit 257 Buffer memory 258 Memory controller 259 Built-in memory 260 External interface 261 SDRAM
DESCRIPTION OF SYMBOLS 300 Imaging optical system 301 Objective lens 302 Prism 303 Zoom lens 304 Aperture unit 305 Shutter unit 306 Zoom lens 307 Focus lens 308 Low pass filter 400 Water repellent system 401 Housing 401a Rib 402 Water repellent filter receiving rubber 403 Water repellent filter 404 Piezoelectric element 405 Water repellent filter receiving rubber 406 Water repellent filter receiving member 407 Optical window 500 Water repellent system drive unit 501 Logic circuit 502 FET
503 transformer

Claims (6)

A housing having an opening for guiding subject light to the imaging optical system;
A transparent diaphragm provided in the opening;
Vibration means for vibrating the transparent diaphragm;
An imaging apparatus comprising: The imaging optical system is
A bending optical system,
The imaging apparatus according to claim 1. The vibration means is
A piezoelectric element,
The imaging apparatus according to claim 1, wherein the imaging apparatus is configured as described above. The vibration means is
Driven in multiple frequency bands including resonant frequency,
The imaging apparatus according to any one of claims 1 to 3, wherein the imaging apparatus is characterized. The vibration means is
Arranged at the periphery of the transparent diaphragm,
The imaging apparatus according to claim 1. The transparent diaphragm is
Is roughly square,
The vibration means is
Arranged along one side or a pair of opposite sides of the transparent diaphragm,
The imaging apparatus according to claim 1.

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