JP2004032289A - Electronic imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic imaging apparatus having a dust removing mechanism, capable of vibrating a dustproof filter under an optimal state without complicating the driving circuit of a piezoelectric element. <P>SOLUTION: When the voltage of a battery 154 measured by means of an ADC 160 exceeds a specified level, a dustproof filter drive circuit 140 is controlled, such that the dustproof filter 21 vibrates at a frequency deviated from the resonance frequency. When the voltage of the battery 154, measured by means of an ADC 160, is lower than the specified level, the dustproof filter driving circuit 140 is controlled, such that the dustproof filter 21 vibrates at the resonance frequency. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is directed to an electronic imaging apparatus including an imaging element unit having an imaging element that obtains an image signal corresponding to light irradiated on its own photoelectric conversion surface, such as a single-lens reflex digital camera with interchangeable lenses. The present invention relates to improvement of an electronic imaging device.
[0002]
[Prior art]
In recent years, it has been equipped with a single-lens reflex type finder device, and a photographic optical system is configured to be detachable from the camera body, so that the user can freely attach and detach a desired photographic optical system when desired. A so-called interchangeable lens type digital camera, which is configured so that a plurality of types of photographing optical systems can be selectively used in a single camera body by replacing the same, is being generally put into practical use.
[0003]
In such a lens-replaceable digital camera, dust or the like floating in the air may enter the inside of the camera body when the photographing optical system is removed from the camera body. Further, since various mechanically operated mechanisms such as a shutter and an aperture mechanism are provided inside the camera body, dusts and the like are generated from the various mechanisms during the operation. In some cases.
[0004]
In view of this, the present applicant has previously provided in Japanese Patent Application No. 2000-401291 a dustproof member that seals and protects the side of the photoelectric conversion surface of the imaging device, so that dust and the like adhere to the photoelectric conversion surface of the imaging device. And a technique for removing dust and the like adhering to the dustproof member by applying vibration of a predetermined amplitude to the dustproof member using predetermined vibration means.
[0005]
According to this technology, it is possible to use a small and simple mechanism to prevent dust from adhering to the photoelectric conversion surface of the image sensor, and to replace the lens that can easily remove dust and the like adhering to the surface of the dustproof member. It is possible to configure a digital camera of various forms.
[0006]
[Problems to be solved by the invention]
In the digital camera described above, a dust filter (glass) is disposed on the front side of the image sensor as a dust-proof member, and a piezoelectric element is provided as a vibrating means so as to be integrated with the periphery of the dust filter. Then, the piezoelectric element is vibrated by applying a periodic voltage to the piezoelectric element, and a predetermined vibration is given to the dustproof filter by the vibration.
[0007]
However, since the amount of displacement of the piezoelectric element itself during vibration is small, it is not possible to efficiently remove dust even if the dust filter is vibrated only by the amount of displacement of the piezoelectric element. Therefore, in order to increase the amplitude of vibration of the dust filter, it is necessary to vibrate at a unique resonance frequency of the dust filter itself. Further, even when a high voltage is applied to the piezoelectric element, the displacement of the piezoelectric element increases, so that a vibration having a large amplitude can be generated by the dustproof filter.
[0008]
However, if the amplitude of the dust filter becomes too large, the dust filter itself may be broken. In particular, in the case of an electronic imaging device using a battery as a driving power source, a difference occurs in the amplitude of the dustproof filter according to the battery voltage. For this reason, if the dustproof filter is set so that a large amplitude can be obtained even at a relatively low voltage, the above-described accident that the dustproof filter is broken in the case of a new battery may occur.
[0009]
The present invention has been made in view of the above circumstances, and provides an electronic imaging apparatus having a dust removal mechanism that can vibrate a dustproof filter in an optimal state without complicating the configuration of a driving circuit of a piezoelectric element. The purpose is to provide.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, an electronic imaging device according to the present invention includes: an imaging unit that converts an optical image of a subject into an electric signal; a dust filter disposed on a front surface of the imaging unit; and a vibration unit that vibrates the dust filter. Exciting means, and measuring means for measuring a power supply voltage, comprising: the exciting means changes the oscillation frequency of the vibration isolation filter according to the power supply voltage measured by the measuring means. I do.
[0011]
That is, the electronic imaging device of the present invention changes the vibration frequency of the anti-vibration filter according to the power supply voltage measured by the measurement unit when the dust-proof filter disposed on the front surface of the imaging unit is vibrated by the vibration unit.
[0012]
In order to achieve the above object, an electronic imaging apparatus according to the present invention includes an imaging unit that converts an optical image of a subject into an electric signal, a dustproof filter disposed on a front surface of the imaging unit, and the dustproof filter. Vibrating means for vibrating, and measuring means for measuring a power supply voltage, wherein the vibrating means changes a time for vibrating the dustproof filter according to the power supply voltage measured by the measuring means. Features.
[0013]
That is, the electronic imaging apparatus of the present invention changes the time for oscillating the anti-vibration filter according to the power supply voltage measured by the measurement unit when the dust-prevention filter disposed in front of the imaging unit is vibrated by the vibration unit. .
[0014]
In order to further achieve the above object, an electronic imaging device according to the present invention includes an imaging device, a dustproof filter provided on a front surface of the imaging device, and a piezoelectric device provided on a peripheral portion of the dustproof filter. A driving circuit that vibrates the piezoelectric element, a measuring circuit that measures power supply voltage and outputs digital data, and adjusts a frequency signal for vibrating the piezoelectric element according to a measurement result of the measuring circuit. And a control circuit for supplying to the drive circuit, comprising: a dust removing mechanism that vibrates the dust filter by the vibration of the piezoelectric element, thereby removing dust attached to the surface of the dust filter. I do.
[0015]
That is, the electronic imaging device according to the present invention supplies the piezoelectric element disposed on the periphery of the dustproof filter to the drive circuit by the control circuit in accordance with the power supply voltage measured by the measurement circuit when the piezoelectric element is vibrated by the drive circuit. Adjust the frequency signal.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 2 is a diagram illustrating a schematic configuration when the electronic imaging device according to the first embodiment of the present invention is applied to a digital camera. That is, FIG. 2 is a perspective view schematically showing an internal configuration of the camera by cutting a part of the camera.
[0017]
The camera 1 includes a camera body 11 and a lens barrel 12 which are separately formed. At this time, the camera body 11 and the lens barrel 12 are configured to be detachable from each other.
[0018]
The lens barrel 12 is configured to internally hold a photographing optical system 12a including a plurality of lenses and a driving mechanism thereof. The photographing optical system 12a transmits a light beam from the subject so that an image of the subject formed by the subject light beam is formed at a predetermined position, that is, on a photoelectric conversion surface of an image sensor described later, for example. , A plurality of optical lenses and the like. The lens barrel 12 is provided so as to protrude toward the front of the camera body 11.
[0019]
The camera body 11 is provided with various constituent members and the like, and is a photographing optical system which is a connecting member for detachably disposing the lens barrel 12 holding the photographing optical system 12a. This is a so-called single-lens reflex camera configured to have the mounting portion 11a provided on the front surface thereof.
[0020]
That is, an exposure opening having a predetermined diameter capable of guiding a subject light beam into the camera body 11 is formed at a substantially central portion on the front side of the camera body 11. A photographing optical system mounting portion 11a is formed.
[0021]
On the outer surface side of the camera body 11, the above-described photographing optical system mounting portion 11a is provided on the front surface, and various operations for operating the camera body 11 at predetermined positions such as the upper surface portion and the back surface portion are provided. A member such as a release button 17 for generating an instruction signal or the like for starting a photographing operation is provided.
[0022]
Inside the camera body 11, various components, for example, a finder device 13 forming a so-called observation optical system, and a shutter mechanism for controlling the irradiation time of the subject light beam to the photoelectric conversion surface of the image sensor and the like are provided. A shutter unit 14, an image sensor (not shown) for obtaining an image signal corresponding to the subject image, and a shutter unit 14, which is disposed at a predetermined position on the front side of the photoelectric conversion surface of the image sensor to prevent dust and the like from adhering to the photoelectric conversion surface. An image pickup unit 15 including a dustproof filter (also referred to as dustproof glass) 21 as a dustproof member to be prevented, and a plurality of circuit boards including a main circuit board 16 on which various electrical members constituting an electrical circuit are mounted, Each is provided at a predetermined position. In FIG. 2, illustration of circuit boards other than the main circuit board 16 is omitted.
[0023]
The finder device 13 includes a reflecting mirror (quick return mirror) 13b configured to bend the optical axis of the subject light beam transmitted through the photographing optical system 12a and guide it toward the observation optical system. A pentaprism 13a for receiving an emitted light beam to form an erect erect image, an eyepiece 13c for enlarging an image formed by the pentaprism 13a and forming an image in an optimal form for observation. Have been.
[0024]
The quick return mirror 13b is configured to be movable between a position retracted from the optical axis of the photographing optical system 12a and a predetermined position on the optical axis. In a normal state, the quick return mirror 13b is arranged on the optical axis of the photographing optical system 12a at a predetermined angle with respect to the optical axis, for example, at an angle of 45 degrees. Accordingly, when the camera 1 is in the normal state, the optical axis of the subject light flux transmitted through the photographing optical system 12a is bent by the quick return mirror 13b, and the pentaprism is disposed above the quick return mirror 13b. 13a.
[0025]
On the other hand, while the camera 1 is performing a shooting operation, the quick return mirror 13b moves to a predetermined position retracted from the optical axis of the shooting optical system 12a. As a result, the subject light flux is guided toward the image sensor.
[0026]
As the shutter unit 14, for example, a shutter mechanism of a focal plane system, a driving circuit thereof, and the like that are generally used in a conventional camera or the like are also applied to the present embodiment.
[0027]
Next, details of the imaging unit 15 in the camera 1 will be described below.
3, 4, and 5 are views illustrating a part of the imaging unit 15 of the camera 1. FIG. 3 is an exploded perspective view of a main part of the imaging unit in an exploded manner. FIG. 4 is a perspective view of a part of the imaging unit in an assembled state. Further, FIG. 5 is a cross-sectional view along the cut surface of FIG.
[0028]
The imaging unit 15 of the camera 1 is a unit including a plurality of members including the shutter unit 14 as described above. 3 to 5, only the main part of the imaging unit 15 is illustrated, and the shutter unit 14 is not illustrated. In addition, in order to show the positional relationship between the constituent members, in FIGS. FIG. 2 also shows a main circuit board 16 on which an electric circuit of an imaging system is mounted.
[0029]
It should be noted that the details of the main circuit board 16 itself are applied to those generally used in conventional cameras and the like, and the description thereof is omitted.
[0030]
The imaging unit 15 includes a charge coupled device (hereinafter, referred to as a CCD) or the like, and transmits an imaging optical system 12a to obtain an image signal corresponding to light irradiated on its own photoelectric conversion surface. 27, an image sensor fixing plate 28 made of a thin plate member for fixedly supporting the image sensor 27, and a subject disposed on the photoelectric conversion surface side of the image sensor 27 and irradiated through the imaging optical system 12a. An optical low-pass filter (hereinafter, referred to as an optical LPF) 25, which is an optical element formed to remove a high-frequency component from the light beam, and a peripheral portion between the optical LPF 25 and the image sensor 27, When the low-pass filter receiving member 26 formed of a frame-shaped elastic member or the like and the imaging element 27 are stored and fixedly held, The optical LPF 25 is tightly supported from its peripheral edge portion to its adjacent portion, and an image pickup device housing case member (hereinafter, referred to as a “predetermined portion”) is disposed so as to be in close contact with a dustproof filter receiving member 23 described later. A dust-proof filter receiving member 23 which is disposed on the front side of the CCD case 24 and closely supports the dust-proof filter 21 from its peripheral portion to its vicinity. A dustproof filter 21 that is supported and is opposed to the photoelectric conversion surface of the image sensor 27 and is disposed opposite to the optical LPF 25 at a predetermined position on the front side of the optical LPF 25 at a predetermined distance from the optical LPF 25; A vibrating member that is disposed on the periphery of the dustproof member 21 and applies predetermined vibration to the dustproof filter 21. A piezoelectric element 22 made of 械 conversion element is constituted by the pressing member 20 such as a dust filter 21 from the elastic body for fixing and holding hermetically is bonded to the dust-proof filter receiving member 23.
[0031]
The imaging element 27 receives the subject luminous flux transmitted through the imaging optical system 12a on its own photoelectric conversion surface and performs a photoelectric conversion process to obtain an image signal corresponding to the subject image formed on the photoelectric conversion surface. For example, the above-mentioned CCD is applied. Note that the imaging element 27 corresponds to an imaging unit described in the claims.
[0032]
The image sensor 27 is mounted at a predetermined position on the main circuit board 16 via an image sensor fixing plate 28. The image signal processing circuit and the work memory are mounted on the main circuit board 16 as described above, and the signal output from the image sensor 27 is processed by these circuits.
[0033]
On the front side of the image pickup device 27, an optical LPF 25 is provided with a low-pass filter receiving member 26 interposed therebetween. Then, a CCD case 24 is provided so as to cover this.
[0034]
In other words, the CCD case 24 is provided with a rectangular opening 24c at a substantially central portion, and the optical LPF 25 and the image sensor 27 are arranged in the opening 24c from the rear side. A step portion 24a having a substantially L-shaped cross section is formed on the inner peripheral edge portion on the rear side of the opening 24c as shown in FIGS.
[0035]
As described above, the low-pass filter receiving member 26 made of an elastic member or the like is provided between the optical LPF 25 and the image sensor 27. The low-pass filter receiving member 26 is disposed at a position on the front edge of the imaging element 27 that avoids the effective range of the photoelectric conversion surface, and is in contact with the vicinity of the rear edge of the optical LPF 25. Has become. The low-pass filter receiving section 26 maintains substantially airtightness between the optical LPF 25 and the image sensor 27. In this case, an elastic force in the optical axis direction acts on the optical LPF 25 by the low-pass filter receiving member 26.
[0036]
Therefore, a low-pass filter that displaces the optical LPF 25 in the optical axis direction by arranging the peripheral portion on the front side of the optical LPF 25 so as to be substantially airtightly contacted with the step portion 24a of the CCD case 24. The position of the optical LPF 25 in the optical axis direction is regulated against the elastic force of the receiving member 26.
[0037]
In other words, the position of the optical LPF 25 inserted into the opening 24c of the CCD case 24 from the rear side of the CCD case 24 is regulated by the step portion 24a in the optical axis direction. Thus, the optical LPF 25 does not escape from the inside of the CCD case 24 toward the front side.
[0038]
After the optical LPF 25 is inserted into the opening 24c of the CCD case 24 from the rear side of the CCD case 24 in this manner, the imaging device 27 is disposed on the rear side of the optical LPF 25. . In this case, a low-pass filter receiving member 26 is sandwiched between the optical LPF 25 and the image sensor 27 at the peripheral edge.
[0039]
The image sensor 27 is mounted on the main circuit board 16 with the image sensor fixing plate 28 interposed therebetween as described above. The image sensor fixing plate 28 is fixed to the screw hole 24e from the rear side of the CCD case 24 by a screw 28b via a spacer 28a. The main circuit board 16 is fixed to the image sensor fixing plate 28 by screws 16d via spacers 16c.
[0040]
On the front side of the CCD case 24, a dust filter receiving member 23 is fixed to a screw hole 24b of the CCD case 24 by a screw 23b. In this case, a peripheral groove 24d is formed in a substantially annular shape at a predetermined position on the peripheral side and the front side of the CCD case 24, as shown in detail in FIGS. On the other hand, an annular convex portion 23d (not shown in FIG. 3) corresponding to the peripheral groove 24d of the CCD case 24 is entirely provided at a predetermined position on the peripheral side and the rear side of the dustproof filter receiving member 23. It is formed in a substantially annular shape over the circumference. Therefore, when the annular convex portion 23d and the peripheral groove 24d are fitted, the CCD case 24 and the dustproof filter receiving member 23 are formed in an annular region, that is, an area where the peripheral groove 24d and the annular convex portion 23d are formed. In a substantially airtight manner.
[0041]
The dustproof filter 21 has a circular or polygonal plate shape as a whole. A region of the dustproof filter 21 having at least a predetermined spread in the radial direction from its own center forms a transparent portion, and the transparent portion is disposed to face the front surface of the optical LPF 25 with a predetermined interval therebetween. I have.
[0042]
Also, on one surface of the dustproof filter 21, that is, on the peripheral portion on the rear side in the present embodiment, a predetermined vibrating member for giving vibration to the dustproof filter 21 is provided. The piezoelectric element 22 formed by the above-mentioned method is disposed so as to be integrated, for example, by sticking with an adhesive or the like. The piezoelectric element 22 is configured so that a predetermined vibration can be generated in the dustproof filter 21 by applying a predetermined drive voltage from the outside. Note that the piezoelectric element 22 corresponds to a vibration unit described in the claims.
[0043]
The dustproof filter 21 is fixed and held by a pressing member 20 made of an elastic body such as a leaf spring so as to be airtightly joined to the dustproof filter receiving member 23.
[0044]
A circular or polygonal opening 23f is provided near a substantially central portion of the dustproof filter receiving member 23. The opening 23f is set to be large enough to allow the subject light beam transmitted through the imaging optical system 12a to pass and irradiate the subject light beam onto the photoelectric conversion surface of the image sensor 27 disposed behind. I have.
[0045]
A wall 23e shown in FIGS. 4 and 5 protruding toward the front side is formed in a substantially annular shape at the peripheral edge of the opening 23f, and the front end side of the wall 23e is further toward the front side. While the receiving portion 23c is formed to protrude, a plurality of (three in this embodiment) protruding portions 23a are provided at predetermined positions near the outer peripheral edge on the front side of the dustproof filter receiving member 23. It is formed so as to protrude toward the side. The protruding portion 23a is a portion formed to fix the pressing member 20 for fixing and holding the dustproof filter 21, and the pressing member 20 is screwed to the tip of the protruding portion 23a with a screw 20a or the like. Are fixed by the fastening means.
[0046]
The pressing member 20 is a member formed by an elastic body such as a leaf spring as described above. The base end of the pressing member 20 is fixed to the protruding portion 23a, and the free end abuts on the outer peripheral edge of the dustproof filter 21. Pressing is performed in the axial direction.
[0047]
In this case, a predetermined portion of the piezoelectric element 22 disposed on the outer peripheral edge on the back side of the dustproof filter 21 abuts on the receiving portion 23c, so that the positions of the dustproof filter 21 and the piezoelectric element 22 in the optical axis direction are adjusted. Are being regulated. Thus, the dustproof filter 21 is fixedly held so as to be airtightly joined to the dustproof filter receiving member 23 via the piezoelectric element 22.
[0048]
In other words, the dust-proof filter receiving member 23 is configured to be airtightly joined to the dust-proof filter 21 via the piezoelectric element 22 by the urging force of the pressing member 20.
[0049]
By the way, as described above, the dust-proof filter receiving member 23 and the CCD case 24 are configured such that the circumferential groove 24d and the annular convex portion 23d shown in FIGS. At the same time, the dust filter receiving member 23 and the dust filter 21 are hermetically joined via the piezoelectric element 22 by the urging force of the pressing member 20. The optical LPF 25 disposed in the CCD case 24 is disposed so as to be substantially airtight between the peripheral edge on the front side of the optical LPF 25 and the step portion 24 a of the CCD case 24. Further, on the rear side of the optical LPF 25, an image sensor 27 is provided via a low-pass filter receiving member 26, so that substantially airtightness is maintained between the optical LPF 25 and the image sensor 27. ing.
[0050]
Thus, a predetermined gap 51a is formed in a space between the optical LPF 25 and the dustproof filter 21. A space 51b is formed on the peripheral side of the optical LPF 25, that is, by the CCD case 24, the dust filter receiving member 23, and the dust filter 21. The space 51b is a sealed space formed so as to protrude outside the optical LPF 25 as shown in FIGS.
[0051]
The space 51b is set to be a space wider than the space 51a. The space formed by the gap 51a and the space 51b is a sealed space 51 that is substantially airtightly sealed by the CCD case 24, the dust filter receiving member 23, the dust filter 21, and the optical LPF 25 as described above. ing.
[0052]
As described above, in the imaging unit 15 of the electronic imaging apparatus according to the present embodiment, the sealing structure that forms the substantially sealed space 51 that is formed on the periphery of the optical LPF 25 and the dustproof filter 21 and that includes the gap 51 a is configured. Have been. The sealing structure is provided at a position outside the peripheral portion of the optical LPF 25 or a portion in the vicinity thereof.
[0053]
Further, in the present embodiment, the dust-proof filter receiving member 23, which is the first member that supports the dust-proof filter 21 from the peripheral portion to the vicinity thereof, and the optical LPF 25 from the peripheral portion to the vicinity thereof. A sealing structure is constituted by a CCD case 24 and the like, which is a second member disposed so as to be in close contact with and supported by the dust-proof filter receiving member 23 at a predetermined portion thereof. .
[0054]
In the camera 1 configured as described above, the dust-proof filter 21 is disposed at a predetermined position on the front side of the image sensor 27 so as to be sealed at a peripheral portion between the photoelectric conversion surface of the image sensor 27 and the dust filter 21. The configuration in which the stop space 51 is sealed prevents dust and the like from adhering to the photoelectric conversion surface of the image sensor 27.
[0055]
In this case, with respect to dust and the like adhering to the exposed surface on the front side of the dustproof filter 21, a periodic voltage is applied to the piezoelectric element 22 which is disposed integrally with the periphery of the dustproof filter 21. By applying a predetermined vibration to the dustproof filter 21, the dustproof filter 21 can be removed.
[0056]
FIG. 6 is a front view showing only the dustproof filter 21 and the piezoelectric element 22 provided integrally with the dustproof filter 21 of the imaging unit 15 of the camera 1. FIGS. 7 and 8 are views for explaining a state change of the dust filter 21 and the piezoelectric element 22 when a driving voltage is applied to the piezoelectric element 22 of FIG. That is, FIG. 7 is a cross-sectional view along the line AA in FIG. 6, and FIG. 8 is a cross-sectional view along the line BB in FIG.
[0057]
Here, for example, when a negative (minus;-) voltage is applied to the piezoelectric element 22, the dustproof filter 21 is deformed as shown by a solid line from the center C in FIGS. On the other hand, when a positive (plus; +) voltage is applied to the piezoelectric element 22, the dustproof filter 21 is deformed as shown by a two-dot chain line from the center C in FIG.
[0058]
In this case, since the amplitude is substantially zero at the position of the vibration node 21a shown in FIGS. 6 to 8, the receiving portion 23c of the dustproof filter receiving member 23 is brought into contact with a portion corresponding to the node 21a. Set as follows. Thereby, the dustproof filter 21 can be efficiently supported without hindering the vibration.
[0059]
In this state, the dust-proof filter 21 is vibrated by applying a periodic voltage to the piezoelectric element 22 by controlling a dust-proof filter driving circuit described later at a predetermined time, and the dust-proof filter 21 The attached dust is removed.
[0060]
The resonance frequency of the vibration at this time is determined by the shape, plate thickness, material and the like of the dustproof filter 21. Further, in the examples shown in FIGS. 6 to 8 described above, the case where the primary vibration is generated is shown. However, the present invention is not limited to this, and a higher-order vibration may be generated.
[0061]
FIG. 1 is a block diagram showing a configuration of a camera system equipped with an electronic imaging device according to the first embodiment of the present invention.
[0062]
This camera system mainly includes a lens barrel 12 as an interchangeable lens and a camera body 11, and a desired lens barrel 12 is detachably set on the front surface of the camera body 11.
[0063]
The lens barrel 12 is controlled by a lens control microcomputer (hereinafter referred to as “Lucom”) 205. The control of the camera body 11 is performed by a body control microcomputer (hereinafter, referred to as Bucom) 150. The Lucom 205 and the Bucom 150 are electrically connected via the communication connector 206 so that they can communicate when the camera body 11 and the lens barrel 12 are combined. In this state, the Lucom 205 operates as a camera system while subordinately cooperating with the Bucom 150.
[0064]
In the lens barrel 12, a photographing optical system 12a and an aperture 203 are provided. The photographing optical system 12a is driven by a DC motor (not shown) in the lens driving mechanism 202. The aperture 203 is driven by a stepping motor (not shown) provided in the aperture driving mechanism 204. At this time, the Lucom 205 controls each of these motors according to the command of the Bucom 150.
[0065]
The following components are arranged in the camera body 11 as shown in the figure. For example, the components of a single-lens reflex system (quick return mirror 13b, pentaprism 13a, eyepiece 13c, and sub-mirror 114) as an optical system, a focal plane type shutter unit 14 on the optical axis, and the sub-mirror 114 An AF sensor unit 116 for receiving the reflected light beam and automatically measuring the distance is provided.
[0066]
Also, an AF sensor driving circuit 117 for driving and controlling the AF sensor unit 116, a mirror driving mechanism 118 for driving and controlling the quick return mirror 13b, and a spring for driving the front curtain and rear curtain of the shutter unit 14 are charged. A shutter charge mechanism 119, a shutter control circuit 120 for controlling the movement of the front curtain and the rear curtain, and a photometric circuit 121 for performing photometric processing based on the light beam from the pentaprism 13a are provided.
[0067]
On the optical axis, an imaging unit 15 for photoelectrically converting a subject light beam passing through the imaging optical system 12a is provided as a photoelectric conversion element, and further disposed between the imaging unit 15 and the imaging optical system 12a. It is protected by a dustproof filter 21 as an optical element. For example, a piezoelectric element 22 is attached to the periphery of the dustproof filter 21 as a part of a vibration unit that vibrates the dustproof filter 21 at a predetermined frequency.
[0068]
The piezoelectric element 22 is configured so that the dust-proof filter 21 is vibrated by a dust-proof filter driving circuit 140 as a part of the vibrating means, so that dust adhering to the surface thereof can be removed. Therefore, this camera system is an electronic camera having a basic structure belonging to a so-called “camera with dustproof function”.
[0069]
Note that a temperature measurement circuit 133 is provided near the dustproof filter 21 to measure the temperature around the image sensor 27.
The camera system also includes an interface circuit 123 connected to the image sensor 27, a liquid crystal monitor 124, an SDRAM 125 provided as a storage area, a flash ROM 126, an image processing controller 128 for performing image processing using a recording medium 127, and the like. It is configured to provide an electronic record display function together with an electronic imaging function.
[0070]
As another storage area, a nonvolatile memory 129 composed of, for example, an EEPROM is provided so as to be accessible from the Bucom 150 as a nonvolatile storage means for storing predetermined control parameters necessary for camera control.
[0071]
Further, the Bucom 150 is provided with an operation display LCD 151 for notifying a user of the operation state of the camera 1 by a display output, and a camera operation SW 152. The camera operation SW 152 is a group of switches including operation buttons necessary for operating the camera, such as a release SW, a mode change SW, and a power SW.
[0072]
Further, a battery 154 as a power supply and a power supply circuit 153 for converting a voltage of the power supply into a voltage required by each circuit unit constituting the camera system and supplying the converted voltage are provided. The voltage of the battery 154 is converted into digital data by an A / D conversion circuit (hereinafter, referred to as an ADC) 160 provided in the Bucom 150. At this time, the Bucom 150 can check the state of the battery 154 based on the digital data. The ADC 160 corresponds to a measuring unit described in the claims.
[0073]
In the camera system configured as described above, each unit operates as follows. The image processing controller 128 controls the interface circuit 123 in accordance with a command from the Bucom 150 to capture image data from the image sensor 27. This image data is converted into a video signal by the image processing controller 128 and output and displayed on the liquid crystal monitor 124. The user can check the captured image from the display image on the liquid crystal monitor 124.
[0074]
The SDRAM 125 is a memory for temporarily storing image data, and is used as a work area when the image data is converted. The image data is set to be stored in the recording medium 127 after being converted into JPEG data.
[0075]
The image sensor 27 is protected by a dust filter 21 having a transparent glass surface. A piezoelectric element 22 for vibrating the glass surface is arranged at the periphery of the dust filter 21. The piezoelectric element 22 is driven by a dust filter driving circuit 140 as will be described later in detail. It is more preferable that the image pickup element 27 and the piezoelectric element 22 are integrally accommodated in a case surrounded by a frame as shown by a broken line with the dustproof filter 21 as one surface, for dustproofing.
[0076]
In addition, temperature usually affects the elastic modulus of a glass material and is one of the factors that change the natural frequency of the material. Therefore, during operation, the temperature is measured and the natural frequency changes. Must be considered. At this time, it is better to measure the temperature change of the dustproof filter 21 provided to protect the front surface of the image sensor 27 whose temperature rises sharply during operation, and to predict the natural frequency at that time.
[0077]
Therefore, in the case of the present embodiment, a sensor (not shown) connected to the temperature measurement circuit 133 is provided to measure the ambient temperature of the image sensor 27. It is preferable that the temperature measurement point of the sensor is set very close to the vibration surface of the dustproof filter 21.
[0078]
The mirror driving mechanism 118 is a mechanism for driving the quick return mirror 13b to the UP position and the DOWN position. When the quick return mirror 13b is at the DOWN position, the light flux from the photographing optical system 12a is transmitted to the AF sensor unit 116 side. Is divided and guided to the pentaprism 13a side.
[0079]
The output from the AF sensor in the AF sensor unit 116 is transmitted to the Bucom 150 via the AF sensor drive circuit 117, and a known distance measurement process is performed.
In addition, while the user can view the subject from the eyepiece 13c adjacent to the pentaprism 13a, a part of the subject luminous flux passing through the pentaprism 13a is guided to a photosensor (not shown) in the photometry circuit 121. A well-known photometric process is performed based on the detected light amount.
[0080]
Next, the driving and operation of the dustproof filter 21 of the electronic imaging device according to the first embodiment will be described based on the circuit diagram of the dustproof filter driving circuit 140 shown in FIG. 9 and the time chart of FIG.
The dustproof filter driving circuit 140 exemplified here has a circuit configuration as shown in FIG. 9, and waveform signals (Sig1 to Sig4) represented by the time chart of FIG. Is controlled as follows. That is, as shown in FIG. 9, the dust filter drive circuit 140 includes an N-ary counter 141, a 1/2 frequency divider 142, an inverter 143, a plurality of MOS transistors (Q00, Q01, Q02) 144a, 144b, 144c, and a transformer 145. , And a resistor (R00) 146.
[0081]
By the ON / OFF switching operation of the transistor (Q01) 144b and the transistor (Q02) 144c connected to the primary side of the transformer 145, a signal (Sig4) of a predetermined cycle is generated on the secondary side of the transformer 145. While driving the piezoelectric element 22 variously based on the signal of the predetermined cycle, an effective resonance frequency is searched for and the dustproof filter 21 is effectively resonated. The details will be described later.
[0082]
The Bucom 150 controls the dust filter drive circuit 140 as follows through two IO ports provided as control ports, namely, the IO port P_PwCont and the IO port D_NCnt, and the clock generator 155 existing inside the Bucom 150. The clock generator 155 outputs a pulse signal (basic clock signal) to the N-ary counter 141 at a frequency sufficiently higher than the signal frequency applied to the piezoelectric element 22. This output signal is a signal Sig1 having a waveform represented by the time chart in FIG. Then, the basic clock signal is input to the N-ary counter 141.
[0083]
The N-ary counter 141 counts the pulse signal and outputs a count end pulse signal each time the pulse signal reaches a predetermined value “N”. That is, the basic clock signal is divided by 1 / N. This output signal is a signal Sig2 having a waveform represented by the time chart in FIG. Note that the frequency-divided pulse signal does not have a high to low duty ratio of 1: 1. Therefore, the duty ratio is converted to 1: 1 through the 1/2 frequency dividing circuit 142. This converted pulse signal corresponds to the signal Sig3 having a waveform represented by the time chart in FIG.
[0084]
In a High state of the converted pulse signal, the transistor (Q01) 144b to which the signal has been input is turned on. On the other hand, this pulse signal is applied to transistor (Q02) 144c via inverter 143. Therefore, in the low state of the pulse signal, the transistor (Q02) 144c to which this signal has been input is turned on. When the transistor (Q01) 144b and the transistor (Q02) 144c connected to the primary side of the transformer 145 are turned on alternately, a signal having a cycle like the signal Sig4 in FIG. 10 is generated on the secondary side.
[0085]
The winding ratio of the transformer 145 is determined from the output voltage of the unit of the power supply circuit 153 and the voltage required for driving the piezoelectric element 22. Note that the resistor (R00) 146 is provided to restrict an excessive current from flowing through the transformer 145.
[0086]
When driving the piezoelectric element 22, the transistor (Q00) 144a must be in the ON state, and a voltage must be applied from the unit of the power supply circuit 153 to the center tap of the transformer 145. In FIG. 9, ON / OFF control of the transistor (Q00) 144a is performed through the IO port P_PwCont. The set value “N” of the N-ary counter 141 can be set from the IO port D_NCnt. Therefore, the Bucom 150 can arbitrarily change the drive frequency of the piezoelectric element 22 by appropriately controlling the set value “N”.
[0087]
At this time, the frequency of the signal applied to the piezoelectric element 22 can be calculated by the following equation.
[0088]
N: Set value to counter
fpls: frequency of the output pulse of the clock generator
fdrv: frequency of the signal applied to the piezoelectric element
Then
fdrv = fpls / 2N
The calculation based on this equation is performed by the CPU (control means) of the Bucom 150.
[0089]
Further, the control performed by the body control microcomputer (Bucom) 150 will be specifically described.
[0090]
FIG. 11 illustrates a main routine of a control program operating on the Bucom 150. First, when the power switch (not shown) of the camera is turned on, the Bucom 150 starts operating, and in # 0, a process for activating the camera system is executed. The power supply circuit 153 is controlled to supply power to each circuit unit constituting the camera system. In addition, initialization of each circuit is performed.
[0091]
In # 1, the current temperature data is fetched from the temperature measurement circuit 133. This temperature data is information used in the subsequent operation routine of # 2 as necessary.
[0092]
In step # 2, a subroutine "dust removal operation" is called and executed. By vibrating the dustproof filter 21 in this subroutine, the dust removing operation is performed. By executing this operation when the power is turned on, it is possible to unintentionally remove dust adhering to the glass (dustproof filter 21) while the camera is not used for photographing. The detailed operation of this subroutine "dust removal operation" will be described later.
[0093]
Step # 3 is a step that is periodically executed, and is an operation step for detecting the state of the lens barrel 12 by performing a communication operation with the Lucom 205.
[0094]
If it is detected in # 4 that the lens barrel 12 has been attached to the camera body 11, the process proceeds to # 7. On the other hand, when it is detected that the lens barrel 12 has been detached from the camera body 11, the process proceeds from # 5 to # 6. Then, at step # 6, the control flag F_Lens is set to "0". Thereafter, the process proceeds to # 10. The control flag indicates “1” during a period when the lens barrel 12 is mounted on the camera body 11 of the camera, and indicates “0” during a period when the lens barrel 12 is removed.
[0095]
In # 7, the control flag F_Lens is set to "1".
[0096]
In # 8, the temperature measurement operation is performed, and in # 9 immediately after that, a subroutine "dust removal operation" for removing dust from the dustproof filter 21 is called and executed. Thereafter, the process proceeds to # 10.
[0097]
Usually, during the period when the lens barrel 12 is not mounted on the camera body 11, there is a high possibility that dust adheres to the lens, the dustproof filter 21, and the like. Therefore, it is desirable to execute the operation of dusting at the timing when the attachment of the lens barrel 12 is detected. Therefore, it is conceivable to execute the operations of # 8 and # 9 periodically. However, in this case, the dustproof filter 21 is often vibrated in a state where dust is not attached, and wasteful power can be consumed. High. For this reason, in the present embodiment, an operation of dusting according to the presence or absence of the lens mounting operation is performed.
[0098]
In # 10, the state of the camera operation SW 152 is detected. Then, when the ON state of the mode change SW (not shown), which is one of the camera operation SWs 152, is detected in # 11, the process proceeds to # 12.
[0099]
In # 12, the operation mode of the camera is changed in conjunction with the operation of the mode change SW, and in # 13, information corresponding to the operation mode is displayed on the operation display LCD 151. Then, the process returns to step # 3.
[0100]
On the other hand, if the ON state of the camera operation SW 152 is not detected in # 10, the process proceeds to # 14. In # 14, it is determined whether or not a first release SW (not shown), which is one of the camera operation switches, has been operated. If the first release SW is ON, the process proceeds to step # 15. If the first release SW is OFF, the process returns to step # 3.
[0101]
In step # 15, the luminance information of the subject is obtained from the photometry circuit 121. From this information, the exposure time (Tv value) of the image sensor 27 and the aperture setting value (Av value) of the photographing optical system 12a are calculated.
[0102]
In # 16, the detection data of the AF sensor unit 116 is obtained via the AF sensor drive circuit 117. The amount of defocus is calculated based on this data.
[0103]
Here, in # 17, the state of the control flag F_Lens is determined. If F_Lens is “0”, it means that the lens unit 10 is not attached, and the photographing operation after # 18 cannot be executed. Therefore, in this case, the process returns to step # 3.
[0104]
On the other hand, if F_Lens is “1”, in # 18, the focus shift amount calculated in # 16 is transmitted to the Lucom 205, and the drive of the photographing optical system 12a based on the shift amount is commanded.
[0105]
In # 19, it is determined whether or not a second release switch (not shown), which is one of the camera operation switches 152, has been operated. When the second release switch is in the ON state, the flow shifts to step # 20 to perform a predetermined photographing operation. On the other hand, when it is in the OFF state, the process returns to step # 3.
[0106]
In step # 20, the Av value is transmitted to the Lucom 205 to instruct the aperture 203 to be driven. Then, in # 21, the quick return mirror 13b is moved to the UP position. Next, in step # 22, the front curtain of the shutter unit 14 is started, and in step # 23, the image processing controller 128 is instructed to execute a shooting operation. When the exposure to the image sensor 27 is completed for the time indicated by the Tv value, the rear curtain running of the shutter unit 14 is started in # 24, and the quick return mirror 13b is driven to the Down position in # 25. At the same time, the charging operation of the shutter unit 14 is performed.
[0107]
In step # 26, the Lucom 205 is instructed to return the aperture 203 to the open position, and in step # 27, the image processing controller 128 is instructed to record the photographed image data on the recording medium 127. . When the recording of the image data is completed, the process returns to step # 3.
[0108]
FIG. 12 is a flowchart for explaining the dust removal subroutine. In this subroutine, measures are taken to prevent an accident that the battery voltage is too high, the amplitude of the dustproof filter 21 becomes large, and as a result, the dustproof filter 21 is broken. FIG. 13 is a distribution diagram showing a relationship between an excitation frequency when the dustproof filter 21 is vibrated and a vibration amplitude of the dustproof filter 21 at that time in order to explain the concept.
[0109]
In FIG. 13, the horizontal axis represents the frequency (vibration frequency) at which the dustproof filter 21 vibrates, and the vertical axis represents the amplitude of the dustproof filter 21 during vibration. As described above, the dustproof filter 21 has the maximum amplitude around the resonance frequency (indicated by f0 in the figure). However, when the battery voltage is higher than a certain level (Vref), the dustproof filter 21 exceeds the amplitude limit value P and may be damaged (this area is indicated by hatching in the figure, and hereinafter referred to as “dangerous area”). Call). The higher the battery voltage, the wider the width of the danger zone for the excitation frequency becomes around the resonance point. On the other hand, if the battery voltage is equal to or lower than Vref, the maximum amplitude does not reach the dangerous area even if the battery vibrates at the resonance frequency. Therefore, Vref is defined as "the voltage at which the dust filter 21 may be broken when the dust filter 21 is vibrated at the resonance frequency".
[0110]
In order to prevent the above-described "accident that the battery voltage is too high and the dustproof filter 21 is destroyed", for example, a pressure reducing circuit such as a regulator may be provided. That's not a good idea.
[0111]
Therefore, in the present embodiment, only when the battery voltage is higher than Vref, the excitation frequency is shifted from the resonance frequency f0 of the dustproof filter 21 and the frequency of the dustproof filter 21 is changed to the frequency f1 where the amplitude does not exceed the limit value P. Is set to vibrate. This frequency f1 is called “safety frequency” or “non-destructive frequency” for convenience.
[0112]
Hereinafter, the above-described dust removing operation will be described with reference to FIG.
[0113]
First, the battery voltage is measured at # 31. This is performed by A / D converting the battery voltage by the ADC 160 built in the Bucom 150.
[0114]
Next, it is determined whether or not the battery voltage measured in # 32 is higher than the above-mentioned Vref. If the battery voltage is higher than Vref, the process proceeds to # 33. On the other hand, if it is not higher, the process proceeds to # 36.
[0115]
When the battery voltage is equal to or lower than Vref, the dustproof filter 21 is not destroyed even when vibrating at the resonance frequency. Therefore, in # 36, the vibration operation is started after setting the vibration frequency to the resonance frequency f0, and then the process proceeds to # 34. The resonance frequency f0 corresponds to the first frequency described in the claims.
[0116]
On the other hand, if the battery voltage is higher than Vref, it is dangerous to vibrate at the resonance frequency, so the excitation frequency is set to f1 (safe frequency) in # 33 and the process proceeds to # 34. Note that the safety frequency f1 corresponds to a second frequency described in the claims.
[0117]
In # 34, the control waits for a predetermined time, for example, about 100 ms, and after performing the vibration operation for 100 ms, terminates the vibration operation in # 35. Then, the process returns to the main routine.
[0118]
Note that the two types of frequencies used here change depending on the variation of components used in the dust removal mechanism including the dustproof filter 21 and the state of assembly, and are frequencies unique to the dustproof filter 21. Therefore, these frequency values are measured at the time of assembling the dust removing mechanism or the like, stored in a nonvolatile memory such as an EEPROM for each electronic imaging device, and read out and used when executing the dust removing operation. In addition, as described above, these frequencies may change due to temperature changes. Therefore, the temperatures are measured by the temperature measurement circuit 133, and these frequencies are corrected according to the measured temperatures.
[0119]
As described above, in the first embodiment of the present invention, when the battery voltage is higher than a predetermined voltage, the vibration frequency is shifted from the resonance frequency f0 of the dustproof filter, and the dustproof filter may be broken. Since the dustproof filter is vibrated within a non-existent range, the dustproof filter is not destroyed even when the battery voltage is high.
[0120]
[Second embodiment]
A second embodiment of the present invention will be described with reference to FIG. Note that the components of the imaging apparatus according to the second embodiment are the same as those in the above-described first embodiment, and a description thereof will be omitted. In addition, the operation of the main routine of the control program that operates on the Bucom 150 is the same as that of the first embodiment described above, and the description thereof is also omitted.
[0121]
FIG. 14 is a flowchart of a dust removal subroutine of the imaging device according to the second embodiment of the present invention.
In the first embodiment, the destruction of the dustproof filter 21 is prevented by changing the vibration frequency. In the second embodiment, the driving time is adjusted according to the battery voltage. . This is based on the idea that, even if the battery voltage is higher than Vref, the risk of destruction will be reduced if the oscillation time is short.
[0122]
First, the battery voltage is measured in # 41. This is the same as # 31 in FIG.
Next, the vibration at the frequency f0 (resonance frequency) is started in # 42.
Thereafter, in # 43, it is determined whether or not the battery voltage is higher than Vref. On the other hand, if it is not high, the flow shifts to # 46, and waits for the second predetermined time to elapse. Here, it is assumed that the first predetermined time is set shorter than the second predetermined time.
Thereafter, the flow shifts to step # 45 to end the vibration operation, and returns to the main routine.
[0123]
By the way, the two predetermined times vary according to the variation of parts used in the dust removing mechanism including the dustproof filter 21 and the assembling condition, similarly to the resonance frequency f0 and the safety frequency f1 in the first embodiment. It is. Therefore, it may be measured at the time of assembling the dust removing mechanism or the like, and stored in a nonvolatile memory such as an EEPROM for each electronic imaging device.
[0124]
As described above, in the second embodiment of the present invention, when the battery voltage is higher than a predetermined voltage, the vibration time is shortened to terminate the vibration operation before the dustproof filter is broken. As a result, the dustproof filter is not destroyed even when the battery voltage is high.
[0125]
Although the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the present invention. is there.
[0126]
【The invention's effect】
As described in detail above, according to the present invention, there is provided an electronic imaging apparatus having a dust removing mechanism that can vibrate a dustproof filter in an optimal state without complicating the configuration of a driving circuit for a piezoelectric element. be able to.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a camera system equipped with an electronic imaging device according to a first embodiment of the present invention.
FIG. 2 is a perspective view schematically showing an internal configuration of the electronic imaging device according to the first embodiment of the present invention, showing a part of the camera as an example of the electronic imaging device.
FIG. 3 is an exploded perspective view showing a main part of the imaging unit in an exploded manner.
FIG. 4 is a perspective view showing a part of the imaging unit in an assembled state by cutting away;
FIG. 5 is a cross-sectional view of the imaging unit along a cut surface of FIG.
FIG. 6 is a front view showing only a dustproof filter and a piezoelectric element provided integrally with the dustproof filter out of the imaging unit.
FIG. 7 is a sectional view taken along line AA of FIG. 6;
FIG. 8 is a sectional view taken along the line BB of FIG. 6;
FIG. 9 is a circuit diagram of a dustproof filter driving circuit.
FIG. 10 is a time chart at the time of operation of a dustproof filter driving circuit.
FIG. 11 is a flowchart showing a main routine of a control program operated by a body control microcomputer (Bucom).
FIG. 12 is a flowchart illustrating a dust removal subroutine.
FIG. 13 is a distribution diagram illustrating a relationship between an excitation frequency when the dust filter is vibrated and a vibration amplitude of the dust filter.
FIG. 14 is a flowchart illustrating a dust removal subroutine according to the second embodiment of the present invention.
[Explanation of symbols]
12 lens barrel
13a Penta prism
13b reflector (quick return mirror)
13c eyepiece
14 Shutter section
15 Imaging unit
21 Dustproof filter
22 Piezoelectric element
27 Image sensor
114 Submirror
116 AF sensor unit
117 AF sensor drive circuit
118 Mirror drive mechanism
119 Shutter charge mechanism
120 Shutter control circuit
121 Photometric circuit
123 Interface Circuit
124 LCD monitor
125 SDRAM
126 FlashROM
127 Recording media
128 Image processing controller
129 Non-volatile memory
133 Temperature measurement circuit
140 Dustproof filter drive circuit
141 N-ary counter
142 1/2 frequency divider
143 inverter
144a, 144b, 144c MOS transistor (transistor)
145 transformer
146 resistance
150 Body control microcomputer (Bucom)
151 LCD for operation display
152 Camera operation switch
153 Power supply circuit
154 batteries
155 clock generator
160 A / D conversion circuit (ADC)
202 Lens drive mechanism
203 aperture
204 Aperture drive mechanism
205 Lens control microcomputer (Lucom)
206 communication connector

Claims (12)

Imaging means for converting an optical image of a subject into an electric signal;
A dustproof filter arranged on the front of the imaging means,
Vibrating means for vibrating the dustproof filter;
Measuring means for measuring the power supply voltage;
With
The electronic imaging device according to claim 1, wherein the vibration unit changes a vibration frequency of the vibration isolation filter according to a power supply voltage measured by the measurement unit. The vibration means vibrates the dustproof filter at a first frequency close to a resonance frequency of the dustproof filter when the power supply voltage is equal to or lower than a predetermined voltage, and when the power supply voltage is higher than the predetermined voltage. The electronic imaging apparatus according to claim 1, wherein the vibration is performed at a second frequency deviating from the resonance frequency. The electronic imaging device according to claim 2, wherein the second frequency is a frequency at which the dustproof filter does not possibly break even if the power supply voltage is higher than the predetermined voltage. 3. The electronic imaging device according to claim 2, wherein the first and second frequencies are values unique to the dustproof filter, and are set at a stage of assembling the electronic imaging device. The electronic imaging device according to claim 2, wherein the predetermined voltage is a voltage at which the dust filter may be broken when the dust filter is vibrated near a resonance frequency of the dust filter. Imaging means for converting an optical image of a subject into an electric signal;
A dustproof filter arranged on the front of the imaging means,
Vibrating means for vibrating the dustproof filter;
Measuring means for measuring the power supply voltage;
With
The electronic imaging device according to claim 1, wherein the vibration unit changes a time period for vibrating the dustproof filter according to a power supply voltage measured by the measurement unit. The vibration means vibrates the dustproof filter for a first predetermined time when the power supply voltage is higher than a predetermined voltage, and causes the dustproof filter to vibrate the first dustproof filter when the power supply voltage is equal to or lower than the predetermined voltage. The electronic imaging apparatus according to claim 6, wherein the vibration is performed for a second predetermined time longer than the predetermined time. The electronic imaging apparatus according to claim 7, wherein the first and second predetermined times are values determined by characteristics of the dustproof filter. An image sensor;
A dust filter disposed on the front of the image sensor;
A piezoelectric element arranged on the periphery of the dustproof filter,
A drive circuit for vibrating the piezoelectric element,
A measurement circuit that measures power supply voltage and outputs digital data;
A control circuit that adjusts a frequency signal for vibrating the piezoelectric element and supplies the frequency signal to the drive circuit according to a measurement result of the measurement circuit;
Including
An electronic imaging apparatus, comprising: a dust removing mechanism that vibrates the dust filter by the vibration of the piezoelectric element, thereby removing dust attached to the surface of the dust filter. 10. The control circuit according to claim 9, wherein the control circuit adjusts a frequency of the frequency signal or a time for supplying the frequency signal to the drive circuit according to a power supply voltage measured by the measurement circuit. Electronic imaging device. The control circuit compares the power supply voltage measured by the measurement circuit with a predetermined value, and when the power supply voltage is equal to or lower than the predetermined voltage, supplies a signal having a frequency close to a resonance frequency of the dustproof filter to the drive circuit. 11. The electronic imaging apparatus according to claim 10, wherein when the power supply voltage is higher than the predetermined value, a signal having a frequency deviating from the resonance frequency is supplied to the drive circuit. The control circuit compares the power supply voltage measured by the measurement circuit with a predetermined value, and when the power supply voltage is higher than a predetermined value, supplies the drive circuit with the frequency signal for a first predetermined time; 10. The electronic imaging apparatus according to claim 9, wherein when the power supply voltage is equal to or less than the predetermined value, the frequency signal is supplied to the drive circuit for a second predetermined time longer than the first predetermined time. apparatus.

Images