JP4857195B2 - Imaging device - Google Patents

Description

  The present invention relates to a technique for removing foreign matter adhering to the surface of an optical element disposed in front of an imaging element in an imaging apparatus such as a digital camera.

  Electronic imaging devices (hereinafter referred to as cameras) typified by digital still cameras and video cameras are rapidly spreading because of their immediacy and high compatibility with personal computers. These cameras obtain image data by subjecting a subject image to photoelectric conversion with an image sensor. As a general minimum configuration, an optical element such as a low-pass filter disposed in front of the image sensor, a photographing optical system, and the image sensor. It consists of.

In the above camera, for example, when a foreign substance such as dust adheres to the optical element, the foreign substance itself is reflected in the image and the image quality is deteriorated. For this reason, various techniques for removing foreign substances adhering by vibrating the optical element have been proposed, and have recently been put into practical use (see Patent Document 1).
JP 2003-333391 A

  By the way, when removing the adhering foreign matter by vibrating the optical element as described above, a vibration apparatus using a piezoelectric element is generally used as a device for vibrating the optical element. For example, when a vibration device using this piezoelectric element breaks down for some reason, vibration applied to the optical element increases, and the optical element may be destroyed.

  When the optical element is destroyed, in order to detect it, there is a problem that it is necessary to perform a photographing operation to check the image, which causes a user to use unnecessary trouble.

  Therefore, the present invention has been made in view of the above-described problems, and an object thereof is to make it possible to easily detect abnormality of a vibration exciter using a piezoelectric element with a simple configuration.

  In order to solve the above-described problems and achieve the object, an imaging apparatus according to the present invention includes an imaging element that photoelectrically converts a subject image, an optical member disposed in front of the imaging element, and both ends of the optical member. The first and second piezoelectric elements respectively disposed on the first and second piezoelectric elements, first and second driving means for independently exciting and driving the first and second piezoelectric elements, and the first and second piezoelectric elements. Detection means including first and second detection piezoelectric elements that are arranged adjacent to each of the piezoelectric elements to detect vibration of the optical member, and vibrates the optical member by vibrating the first piezoelectric element. The vibration of the optical member is detected using the second piezoelectric element for detection, or the optical member is vibrated by vibrating the second piezoelectric element and the first piezoelectric element for detection. Vibration of the optical member using an element To detect, characterized in that it comprises a first control means for controlling said detecting means and said first and second drive means.

  In addition, an imaging apparatus according to the present invention includes an imaging element that photoelectrically converts a subject image, an optical member that is disposed in front of the imaging element, and first and second piezoelectric elements that are respectively disposed at both ends of the optical member. An element, and first and second drive means for independently exciting and driving the first and second piezoelectric elements, respectively, and connected between the first piezoelectric element and the first drive means, A first detecting means for detecting an output signal output from the first piezoelectric element by vibrating the first piezoelectric element; and a connection between the second piezoelectric element and the second driving means. And a second detecting means for detecting an output signal output from the second piezoelectric element as the second piezoelectric element vibrates; and the optical member by vibrating and vibrating the first piezoelectric element. And using the second detection means, The output signal output from the second piezoelectric element is detected, or the second piezoelectric element is vibrated and vibrated to vibrate the optical member, and the first detecting means is used for the first piezoelectric element. First control means for detecting the output signal output from the element.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to detect abnormality of the vibration apparatus using a piezoelectric element easily with a simple structure.

  Hereinafter, a single-lens reflex digital camera equipped with a vibration device using a piezoelectric element according to an embodiment of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram of a single-lens reflex digital camera according to a first embodiment of the present invention.

  In FIG. 1, reference numeral 1 denotes a replaceable photographing lens unit for forming a subject image, 111 denotes a stop provided in the photographing lens unit 1 for adjusting the amount of light incident on the image sensor 2, and 2 denotes a subject image. It is an image sensor for photoelectrically converting. An optical member 4 that also functions as a dust-proof filter such as a low-pass filter or a cover filter is disposed in close proximity to the front surface of the image sensor 2, and foreign matter adheres to the surface of the optical member 4. The attached foreign matter is reflected in the subject image on the image sensor 2 as a shadow. Piezoelectric elements 5 and 6 are disposed on the left and right sides of the optical member 4 (shown in the vertical position in FIG. 1 for the sake of convenience) to vibrate the optical member 4 and remove adhering foreign matter. The piezoelectric elements 5 and 6 are connected to a piezoelectric element driving unit 122 for driving the piezoelectric elements 5 and 6 independently.

  Reference numeral 132 denotes an A / D converter that converts an analog image signal output from the image sensor 2 into a digital signal, and reference numeral 140 denotes an image processing apparatus that processes the digital image signal output from the A / D converter. Reference numeral 133 denotes a lens system controller that controls the lens position and aperture of the photographing lens unit 1, and 121 denotes various sensors such as an AF (autofocus) sensor and an AE (automatic exposure) sensor. Further, 130 is a camera control unit that controls the operation of the entire digital camera, 150 is an I / O with a shutter button, a display, a shooting mode selection dial, and the like, and 134 is a memory that stores captured images and various information.

  User operations are acquired via the I / O 150, and power ON / OFF, shooting operations, and the like are performed according to user operations. When a shooting operation is instructed, the camera control unit 130 determines an appropriate shooting condition based on information obtained from the various sensors 121 and the image sensor 2, and sets an appropriate lens position and the like via the lens system control unit 133. To do. After the exposure, the output signal of the image sensor 2 is digitized via the A / D converter 132, and then subjected to appropriate image processing by the image processing device 140 and stored in the memory 134. If necessary, an image is displayed on a display (not shown) via the I / O 150.

  The image processing apparatus 140 performs processing such as white balance adjustment, RGB development, and compression encoding.

  FIG. 2 is a diagram illustrating an appearance of the single-lens reflex digital camera according to the first embodiment. Specifically, FIG. 2 is a perspective view seen from the front side of the camera, and shows a state in which the taking lens unit is removed.

  In FIG. 2, reference numeral 100 denotes a camera body, which is provided with a grip portion 100a that protrudes forward so that a user can easily hold the camera stably during shooting. Reference numeral 202 denotes a mount unit that fixes the detachable taking lens unit 1 (see FIG. 1) to the camera body. The mount contact 221 has a function of exchanging control signals, status signals, data signals, and the like between the camera body 100 and the photographing lens unit 1 and supplying power to the photographing lens unit. Further, the mount contact 221 may be configured to be capable of not only electrical communication but also optical communication and voice communication.

  Reference numeral 204 denotes a lens lock release button that is pushed in when the photographing lens unit 1 is removed. Reference numeral 205 denotes a mirror box disposed in the camera casing, and the photographic light flux that has passed through the photographic lens is guided here. A quick return mirror 206 is disposed inside the mirror box 205. The quick return mirror 206 is held at an angle of 45 ° with respect to the photographing optical axis in order to guide the photographing light flux in the direction of the pentaprism (not shown), and in the direction of the image sensor 2 (see FIG. 1). In order to guide, it can be in a state of being held at a position retracted from the photographing light flux.

  On the grip side of the upper part of the camera, a shutter button 207 as a start switch for starting shooting, a main operation dial 208 for setting a shutter speed and a lens aperture value according to an operation mode at the time of shooting, and an operation mode of the shooting system A setting button 210 is arranged. Some of the operation results of these operation members are displayed on the LCD display panel 209. The I / O 150 shown in FIG. 1 is mainly an I / O with these operation members, a display panel, and the like.

  The shutter button 207 is configured such that the switch SW1 is turned on by a first stroke (half press) and the switch SW2 is turned on by a second stroke (full press).

  The operation mode setting button 210 is used to set whether the continuous shooting or only one frame shooting is performed when the shutter button 207 is pressed once, the self shooting mode setting, and the like. The setting status is displayed at 209.

  A flash unit 211 that pops up with respect to the camera body, a flash mounting shoe groove 212, and a flash contact 213 are arranged at the upper center of the camera, and a shooting mode setting dial 214 is arranged at the upper right of the camera. The photographing mode setting dial 214 also serves as an activation operation unit for operating the optical member 4 to vibrate by the piezoelectric elements 5 and 6 to remove foreign matters such as dust adhering to the surface of the optical member 4.

  An external terminal lid 215 that can be opened and closed is provided on the side opposite to the grip side. Inside the external terminal lid 215, a video signal output jack 216 and a USB output connector are provided as external interfaces. 217 is stored.

  FIG. 3 is an enlarged view of the vicinity of the image sensor shown in FIG. 1 as viewed from above.

  In FIG. 3, reference numeral 1 denotes a photographic lens, 2 denotes an image sensor for photoelectric conversion of light incident from the photographic lens 1, and 3 denotes an image sensor package for mounting the image sensor 2 on a camera. Reference numeral 4 denotes an optical member that is disposed in front of the image pickup device package 3 and also functions as a dustproof filter for preventing foreign matters such as dust from adhering to the surface of the image pickup device package 3 and the image pickup device 2. The optical member 4 is specifically an optical low-pass filter, an infrared cut filter, or the like. Further, reference numerals 5 and 6 denote driving piezoelectric elements (first piezoelectric element and second piezoelectric element) for vibrating the optical member 4, and reference numerals 21 and 22 denote the optical member 4 sealed in the imaging element package 3. It is a holding member for holding in a state. A detailed configuration of the holding members 21 and 22 will be described later with reference to FIG.

  FIG. 4 is a diagram showing a state of the optical member 4 in FIG. 3 as viewed from the imaging element 2 side and a peripheral circuit of the piezoelectric element (an internal circuit of the piezoelectric element driving unit 122 in FIG. 1).

  In FIG. 4, piezoelectric elements (driving piezoelectric elements) 5 and 6 are attached to the left and right ends of the optical member 4 with the optical member 4 interposed therebetween. Reference numerals 7 and 8 are arranged adjacent to the piezoelectric elements 5 and 6, respectively, and detection piezoelectric elements for detecting the vibration state of the optical member 4 (first detection piezoelectric element and second detection piezoelectric element). It is.

  Reference numeral 9 denotes a drive circuit (first drive means) for driving the piezoelectric element 5, and 10 denotes a drive circuit (second drive means) for driving the piezoelectric element 6. Reference numeral 11 denotes a detection circuit for detecting a signal from the detection piezoelectric element 7, and reference numeral 12 denotes a detection circuit for detecting a signal from the detection piezoelectric element 8.

  The piezoelectric elements 5 and 6 attached to both ends of the optical member 4 are vibrated at a predetermined frequency to generate a standing wave on the optical member 4 to vibrate, and dust or the like adhering to the surface of the optical member 4 The foreign matter is shaken off. Then, the state of the amplitude generated in the optical member 4 is detected by the detecting piezoelectric elements 7 and 8.

  FIG. 5 is a block diagram showing a configuration of a control circuit for controlling the piezoelectric elements 5 and 6 and the detecting piezoelectric elements 7 and 8, and 4, 5, 6, 7, 8, 9, 10, 11, and 12 are diagrams. As described in 4.

  As shown in FIG. 1, 130 is a camera control unit that controls the operation of the entire digital camera and also controls vibration of the piezoelectric elements 5 and 6, and 14 is controlled by the camera control unit 130 to drive the piezoelectric elements 5 and 6. This is an oscillation circuit for outputting a high-frequency signal for the purpose. The oscillation circuit 14 changes the oscillation frequency according to the control value from the camera control unit 130 and outputs an excitation signal. A power supply circuit 15 supplies power for driving the piezoelectric elements 5 and 6 and is connected to the drive circuits 9 and 10.

  Here, the operation of the entire drive control circuit shown in FIGS. 4 and 5 will be described.

  The camera control unit 130 outputs a control signal for instructing a frequency necessary for driving the piezoelectric elements 5 and 6 to the oscillation circuit 14, and the oscillation circuit 14 outputs a signal of the instructed frequency, 9 and 10 are entered. The drive circuits 9 and 10 have a function of outputting the power supplied from the power supply circuit 15 according to signals input from the camera control unit 130 and the oscillation circuit 14 by an H bridge circuit.

  In addition, the camera control unit 130 outputs a drive permission / prohibition signal that instructs the drive circuits 9 and 10 to permit or prohibit driving of the piezoelectric element, thereby determining whether the drive circuits 9 and 10 are output. It can be controlled individually.

  When the output of the drive circuits 9 and 10 is permitted by the camera control unit 130, a drive signal having a frequency specified by the camera control unit 130 is applied to the piezoelectric elements 5 and 6 to vibrate the optical member 4, and the optical member A standing wave is generated on 4. The camera control unit 130 can change the frequency of the signal applied to the piezoelectric element by changing the oscillation frequency of the oscillation circuit 14 by changing the signal sent to the oscillation circuit 14. By changing the frequency in this way, the number of antinodes and nodes of the standing wave generated on the optical member 4 can be changed, and a standing wave having the largest amplitude can be generated.

  When a standing wave is generated in the optical member 4, the detecting piezoelectric elements 7 and 8 vibrate to generate a signal. A signal generated in the detection piezoelectric element 7 is converted into a signal that can be detected by the camera control unit 130 by the detection circuit 11 and input to an A / D conversion input of the camera control unit 130. Similarly, a signal generated in the detection piezoelectric element 8 is converted into a signal that can be detected by the camera control unit 130 by the detection circuit 12 and input to an A / D conversion input of the camera control unit 130.

  Thereby, the camera control unit 130 can monitor the amplitude state of the standing wave generated in the optical member 4 while changing the driving frequency.

  FIG. 6 is a flowchart showing an operation related to vibration control of the optical member 4 of the camera control unit 130. In FIG. 6, the camera control unit 130 starts an operation for dropping foreign matter from the optical member 4 or an operation for testing a foreign matter removal system including the drive circuit and the optical member 4 from step S <b> 101.

  In step S101, the oscillation frequency is instructed to the oscillation circuit 14, thereby initializing the frequency for driving the piezoelectric elements 5 and 6, and the process proceeds to step S102.

  In step S102, it is determined whether the current drive is a test drive or a drive for removing foreign matter. If it is a test drive, the process proceeds to step S112. If it is a drive for removing foreign matter, the process proceeds to step S103.

  In step S103, since the drive operation (third control) for removing foreign matter is performed, it is necessary to maximize the vibration of the optical member 4. Therefore, in order to drive both the piezoelectric elements 5 and 6 attached to the left and right ends of the optical member 4, a drive permission signal is output to both the drive circuits 9 and 10 to drive the piezoelectric elements 5 and 6. Start and go to step S104.

  In step S104, in order to detect the vibration of the optical member 4 and monitor the state of vibration, the signals from the detection circuits 11 and 12 are converted into digital signals by the A / D converter built in the camera control unit 130, Monitor the signal. Then, the process proceeds to step S105.

  In step S105, it is determined whether the output signal from the detection circuit 11 and the output signal from the detection circuit 12 are each equal to or higher than the reference value. If both signals are equal to or higher than the reference value, it is determined that the signal is normal. The process proceeds to step S106. On the other hand, if any one is less than the reference value, it is determined that the output signal is abnormal, and the process proceeds to step S110.

  In step S106, it is determined whether or not a predetermined time has elapsed since the start of driving at the set frequency. If the predetermined time has elapsed, the process proceeds to step S107. If the predetermined time has not elapsed, the process returns to step S104, and the driving at the same frequency is continued and the detection of the vibration state is continued.

  In step S107, the oscillation circuit 14 is instructed to change the frequency, the frequency for driving the piezoelectric elements 5 and 6 is changed, and the process proceeds to step S108. Here, when changing the frequency, the frequency is changed from the previously set frequency to a slightly lower frequency.

  In step S108, it is determined whether or not the frequency set in step S107 exceeds a predetermined frequency change range. If the frequency change within the predetermined frequency change range has been completed, the process proceeds to step S109, and if not complete, the process returns to step S104.

  In step S109, the drive circuits 9 and 10 are prohibited from being driven, and the drive for removing foreign matter is completed.

  On the other hand, in step S110, since the output of either or both of the detection circuits 11 and 12 is abnormal in step S105, the drive circuits 9 and 10 are set in the drive prohibited state, and the process proceeds to step S111.

  In step S111, the abnormal state detected so far is recorded, an abnormal display is displayed on a display device (not shown), and the process proceeds to step S109 to end the driving.

  The abnormalities detected here are abnormalities when the piezoelectric elements at both ends of the optical member 4 are driven to remove foreign matter, and abnormalities such as a drive circuit, a detection circuit, a piezoelectric element, and a detection piezoelectric element are assumed. Is done.

  Next, step S <b> 112 is a step of performing driving for testing, and drives one of the piezoelectric elements attached to both ends of the optical member 4. Then, the vibration state is detected using the piezoelectric elements for detection at both ends, and it is determined whether there is any abnormality. Therefore, the drive circuit 9 is set to drive permission, the drive circuit 10 is prohibited from driving, and only the piezoelectric element 5 is driven, and the process proceeds to step S113.

  In step S113, in order to detect the vibration of the optical member 4 and monitor the vibration state, the signals from the detection circuits 11 and 12 are converted into digital signals by the A / D converter built in the camera control unit 130, Monitor the signal. Then, the process proceeds to step S114.

  In step S114, it is determined whether or not the output of the detection circuit 11 is greater than or equal to a reference value. If it is greater than or equal to the reference value, it is determined that the output is normal and the process proceeds to step S115. If it is less than the reference value, it is determined that the output signal is abnormal, and the process proceeds to step S122.

  In step S115, it is determined whether or not the output of the detection circuit 12 is greater than or equal to a reference value. If it is greater than or equal to the reference value, it is determined that the output is normal and the process proceeds to step S116. If it is less than the reference value, it is determined that the output signal is abnormal, and the process proceeds to step S120.

  In step S116, the drive circuit 10 is set to drive permission and the drive circuit 9 is set to drive prohibition in order to drive the piezoelectric element opposite to the piezoelectric element driven in step S112. Then, only the piezoelectric element 6 is driven, and the process proceeds to step S117.

  In step S117, in order to detect the vibration of the optical member 4 and monitor the state of the vibration, the signals from the detection circuits 11 and 12 are converted into digital signals by the A / D converter built in the camera control unit 130, Monitor the signal. Then, the process proceeds to step S118.

  In step S118, it is determined whether the output of the detection circuit 12 is greater than or equal to a reference value. If it is greater than or equal to the reference value, it is determined that the output is normal, and the process proceeds to step S119. If it is less than the reference value, it is determined that the output signal is abnormal, and the process proceeds to step S122.

  In step S119, it is determined whether or not the output of the detection circuit 11 is greater than or equal to a reference value. If it is greater than or equal to the reference value, it is determined that the output is normal, and the process proceeds to step S109 to end the drive. If it is less than the reference value, it is determined that the output signal is abnormal, and the process proceeds to step S120.

  In step S120, the output of the detection piezoelectric element attached to the same side as the actually driven piezoelectric element is normal, and the output of the detection piezoelectric element attached to the opposite side of the optical member 4 becomes abnormal. Therefore, it is determined that the optical member 4 is abnormal (first control). Then, the process proceeds to step S121.

  In step S121, since it is determined in step S120 that the optical member 4 is abnormal, the optical member 4 may be broken, and a correct image may not be captured. For this reason, processing for prohibiting the subsequent photographing operation is performed, and an abnormal state is recorded in a memory (not shown) or the like. Further, an external display device (not shown) displays that the photographing optical system is abnormal and cannot be photographed, and the process proceeds to step S109 to end the test drive.

  Next, in step S122, since the output of the detecting piezoelectric element attached on the same side as the actually driven piezoelectric element is abnormal, it is highly possible that the piezoelectric element itself is not vibrating. Possible (second control). For this reason, the foreign substance removal operation cannot be performed normally, but unlike the case of proceeding to step S120, it is considered that there is no problem with the photographing optical system, and therefore it is determined that photographing can be performed. The fact that this foreign matter removal drive system is in an abnormal state is recorded in a memory (not shown) or the like. At this time, driving for removing foreign matter is prohibited. Further, it is displayed on the external display device (not shown) that the photographing is possible but the foreign matter removing operation cannot be performed, and the process proceeds to step S109 to end the test drive.

  Next, a specific detection signal in step S105 will be described with reference to FIG.

  10, the horizontal axis 1201 indicates the driving frequency, the vertical axis 1202 indicates the output voltage of the detection circuits 11 and 12, and 1203 indicates the change of the output voltage of the detection circuits 11 and 12 with respect to the driving frequency. Reference numeral 1203 indicates how the output voltages of the detection circuits 11 and 12 change as the drive frequency changes. The waveform changes depending on the vibration state of the optical member 4.

  1204 indicates the level of the determination reference value in step S105. If it is equal to or higher than this determination level, it is determined that the output of the detection circuit 11 or the detection circuit 12 is normal, and if it is equal to or lower than this determination level, Judge as abnormal.

  FIG. 11 shows a case where there is an abnormality in the drive circuits 9 and 10, and shows a state where the output voltages of the detection circuits 11 and 12 are lower than the determination level 1204 as indicated by 1205. .

  Step S118 is a step of determining an abnormality of the drive circuit 10, but the abnormality detection can be performed by the output voltage of the detection circuit 12 as in the case of step S105 (FIGS. 10 and 11).

  Next, a specific detection signal in step S119 will be described.

  In FIG. 12, reference numeral 1206 denotes a detection circuit 11 when only the drive circuit 10 is operated to drive only the piezoelectric element 6 and the vibration state of the optical member 4 is detected by the detection piezoelectric element 7 and the detection circuit 11. The detection signal from is shown. Since this signal is a signal indicating the vibration state of the optical member 4, the output level is often smaller than the signal in step S118. For this reason, the determination level indicated by 1207 is lower than the determination level in step S118.

  In FIG. 13, 1208 is an example of an abnormal signal, and shows a case where the vibration of the optical member 4 is smaller than a predetermined amplitude for some reason. In this case, the detection signal of the detection circuit 11 also has a low value, and an abnormality is detected. Further, when the optical member 4 is damaged, the detection signal is almost “0”, and an abnormality can be detected.

  In this way, for detecting an abnormality in the drive circuit, vibration is detected by the detection piezoelectric element disposed in the vicinity of the drive piezoelectric element. In addition, in order to detect vibration abnormality including the optical element, the vibration is detected by the detection piezoelectric element disposed at a position facing the driving piezoelectric element and the optical element, and the abnormality is determined.

  As described above, in the first embodiment, the detection piezoelectric element is provided in the vicinity of the piezoelectric elements arranged at both ends of the optical member, and the piezoelectric element on one side is driven to pass through the optical member. The vibration is detected by the piezoelectric element for detection on the opposite side. Thereby, the vibration state of the optical member can be detected, and abnormality of the optical member and the piezoelectric element drive system can be detected.

(Second Embodiment)
In the second embodiment, the configuration of the digital camera is the same as that of the first embodiment shown in FIGS. Further, the configuration of the vicinity of the image sensor as viewed from above is the same as that of the first embodiment shown in FIG.

  FIG. 7 shows a state in which the optical member 4 of FIG. 3 is viewed from the imaging element 2 side and a peripheral circuit of the piezoelectric element (internal circuit of the piezoelectric element driving unit 122 in FIG. 1) in the second embodiment. FIG. In FIG. 7, the same components as those in FIG. 4 showing the first embodiment are denoted by the same reference numerals.

  In FIG. 7, the piezoelectric elements 5 and 6 are attached to the left and right ends of the optical member 4.

  Reference numeral 9 denotes a drive circuit for driving the piezoelectric element 5, and reference numeral 10 denotes a drive circuit for driving the piezoelectric element 6. Reference numeral 111 denotes a detection circuit (first detection means) that is connected to a drive signal of the piezoelectric element 5 and detects a drive signal when the piezoelectric element is driven and a signal from the piezoelectric element 5 when not driven. Reference numeral 112 denotes a detection circuit (second detection means) that is connected to a drive signal of the piezoelectric element 6 and detects a drive signal when the piezoelectric element is driven and a signal from the piezoelectric element 6 when not driven.

  The piezoelectric elements 5 and 6 attached to both ends of the optical member 4 are vibrated at a predetermined frequency to generate a standing wave on the optical member 4 to vibrate, and dust or the like adhering to the surface of the optical member 4 The foreign matter is shaken off. The detection circuits 111 and 112 monitor the drive signal during driving of the piezoelectric element, and detect the vibration state of the optical member 4 during non-drive.

  FIG. 8 is a block diagram showing a configuration of a control circuit for controlling the piezoelectric elements 5 and 6, and the same components as those in FIG. 5 showing the first embodiment are denoted by the same reference numerals.

  As shown in FIG. 1, 130 is a camera control unit that controls the operation of the entire digital camera and also controls vibration of the piezoelectric elements 5 and 6, and 14 is controlled by the camera control unit 130 to drive the piezoelectric elements 5 and 6. This is an oscillation circuit for outputting a high-frequency signal for the purpose. The oscillation circuit 14 changes the oscillation frequency according to the control value from the camera control unit 130 and outputs an excitation signal. A power supply circuit 15 supplies power for driving the piezoelectric elements 5 and 6 and is connected to the drive circuits 9 and 10.

  Here, the operation of the entire drive control circuit shown in FIGS. 7 and 8 will be described.

  The camera control unit 130 outputs a control signal for instructing a frequency necessary for driving the piezoelectric elements 5 and 6 to the oscillation circuit 14, and the oscillation circuit 14 outputs a signal of the instructed frequency, 9 and 10 are entered. The drive circuits 9 and 10 have a function of outputting the power supplied from the power supply circuit 15 according to signals input from the camera control unit 130 and the oscillation circuit 14 by an H bridge circuit.

  In addition, the camera control unit 130 outputs a drive permission / prohibition signal that instructs the drive circuits 9 and 10 to permit or prohibit driving of the piezoelectric element, thereby determining whether the drive circuits 9 and 10 are output. It can be controlled individually.

  When the output of the drive circuits 9 and 10 is permitted by the camera control unit 130, a drive signal having a frequency specified by the camera control unit 130 is applied to the piezoelectric elements 5 and 6 to vibrate the optical member 4, and the optical member A standing wave is generated on 4. The camera control unit 130 can change the frequency of the signal applied to the piezoelectric element by changing the oscillation frequency of the oscillation circuit 14 by changing the signal sent to the oscillation circuit 14. By changing the frequency in this way, the number of antinodes and nodes of the standing wave generated on the optical member 4 can be changed, and a standing wave having the largest amplitude can be generated.

  When the piezoelectric elements 5 and 6 are driven, the drive signals of the piezoelectric elements 5 and 6 are detected by the detection circuits 111 and 112, and the detection signals are converted into digital signals by the A / D converter of the camera control unit 130. Detect the state of. In addition, among the piezoelectric elements attached to both ends of the optical member 4, an optical member generated by driving the piezoelectric element on one side is driven by driving the piezoelectric element on one side and not driving the piezoelectric element on the opposite side. 4 standing waves are detected by the piezoelectric element on the opposite side.

  For example, when the piezoelectric element 5 is driven, a signal generated in the piezoelectric element 6 is converted into a signal that can be detected by the camera control unit 130 by the detection circuit 112 and input to an A / D conversion input of the camera control unit 130.

  Thereby, the camera control unit 130 can monitor the state of the drive circuits 9 and 10 and can monitor the amplitude state of the standing wave generated in the optical member 4 while changing the drive frequency.

  FIG. 9 is a flowchart illustrating an operation related to vibration control of the optical member 4 of the camera control unit 130. In FIG. 9, the camera control unit 130 starts an operation for removing foreign matter from the optical member 4 or an operation for testing a foreign matter removal system including the drive circuit and the optical member 4 from step S <b> 201.

  In step S201, an oscillation frequency is instructed to the oscillation circuit 14, thereby initializing the frequency for driving the piezoelectric elements 5 and 6, and the process proceeds to step S202.

  In step S202, it is determined whether the current drive is a test drive or a drive for removing foreign matter. If it is a test drive, the process proceeds to step S212, and if it is a drive for removing foreign matter, the process proceeds to step S203.

  In step S203, since a drive operation for removing foreign matter is performed, it is necessary to maximize the vibration of the optical member 4. Therefore, in order to drive both the piezoelectric elements 5 and 6 attached to the left and right ends of the optical member 4, a drive permission signal is output to both the drive circuits 9 and 10 to drive the piezoelectric elements 5 and 6. Start and proceed to step S204.

  In step S204, in order to monitor the drive signals of the drive circuits 9 and 10 (the vibration state of the optical member 4), the signals from the detection circuits 111 and 112 are digitally converted by an A / D converter built in the camera control unit 130. Convert to signal and monitor the signal. Then, the process proceeds to step S205.

  In step S205, it is determined whether the output signal from the detection circuit 111 and the output signal from the detection circuit 112 are each equal to or greater than the reference value. If both signals are equal to or greater than the reference value, it is determined that the signal is normal. The process proceeds to step S206. On the other hand, if any one is less than the reference value, it is determined that the drive signal is abnormal, and the process proceeds to step S210.

  In step S206, it is determined whether or not a predetermined time has elapsed since driving at the set frequency was started. If the predetermined time has elapsed, the process proceeds to step S207. If the predetermined time has not elapsed, the process returns to step S204, and the drive at the same frequency is continued and the detection of the drive signal is continued.

  In step S207, the oscillation circuit 14 is instructed to change the frequency, the frequency for driving the piezoelectric elements 5 and 6 is changed, and the process proceeds to step S208. Here, when changing the frequency, the frequency is changed from the previously set frequency to a slightly lower frequency.

  In step S208, it is determined whether or not the frequency set in step S207 exceeds a predetermined frequency change range. If the frequency change within the predetermined frequency change range has been completed, the process proceeds to step S209, and if not completed, the process returns to step S204.

  In step S209, the drive circuits 9 and 10 are prohibited from being driven, and the drive for removing foreign matter is completed.

  On the other hand, in step S210, since the output of either or both of the detection circuits 111 and 112 is abnormal in step S205, the drive circuits 9 and 10 are set in the drive prohibited state, and the process proceeds to step S211.

  In step S211, the abnormal state detected so far is recorded, an abnormal display is displayed on a display device (not shown), and the process proceeds to step S209 to end the drive.

  The abnormality detected here is an abnormality in the case where the piezoelectric elements at both ends of the optical member 4 are driven to remove foreign substances, and abnormalities in the drive circuit, the detection circuit, the piezoelectric element, and the like are assumed.

  Next, step S212 is a step of performing driving for testing, and drives one of the piezoelectric elements attached to both ends of the optical member 4. Then, the vibration state is detected using the piezoelectric element on the side opposite to the driving side, and it is determined whether there is an abnormality. For this reason, the drive circuit 9 is set to drive permission, the drive circuit 10 is prohibited from driving, and only the piezoelectric element 5 is driven, and the process proceeds to step S213.

  In step S213, a signal for driving the piezoelectric element 5 is monitored, and the signals from the detection circuits 111 and 112 are monitored by the camera control unit in order to detect the vibration of the optical member 4 by the piezoelectric element 6 and monitor the vibration state. Input to 130. The camera control unit 130 converts a signal input by a built-in A / D converter into a digital signal and monitors the signal. Then, the process proceeds to step S214.

  In step S214, it is determined whether the output of the detection circuit 111 is greater than or equal to a reference value. If it is greater than or equal to the reference value, it is determined that the output is normal, and the process proceeds to step S215. If it is less than the reference value, it is determined that the output signal is abnormal, and the process proceeds to step S222.

  In step S215, it is determined whether or not the output of the detection circuit 112 is greater than or equal to a reference value. If it is greater than or equal to the reference value, it is determined that the output is normal, and the process proceeds to step S216. If it is less than the reference value, it is determined that the output signal is abnormal, and the process proceeds to step S220.

  In step S216, in order to drive the piezoelectric element opposite to the piezoelectric element driven in step S212, the drive circuit 10 is set to drive permission, and the drive circuit 9 is set to drive prohibition. Then, only the piezoelectric element 6 is driven, and the process proceeds to step S217.

  In step S217, in order to monitor the signal for driving the piezoelectric element 6 and to detect the vibration of the optical member 4 with the piezoelectric element 5 and monitor the state of the vibration, the signals from the detection circuits 111 and 112 are monitored by the camera control unit. Input to 130. The camera control unit 130 converts a signal input by a built-in A / D converter into a digital signal and monitors the signal. Then, the process proceeds to step S218.

  In step S218, it is determined whether the output of the detection circuit 112 is greater than or equal to a reference value. If it is greater than or equal to the reference value, it is determined that the output is normal, and the process proceeds to step S219. If it is less than the reference value, it is determined that the output signal is abnormal, and the process proceeds to step S222.

  In step S219, it is determined whether or not the output of the detection circuit 111 is greater than or equal to a reference value. If it is less than the reference value, it is determined that the output signal is abnormal, and the process proceeds to step S220.

  In step S220, since the drive signal to the actually driven piezoelectric element is normal and the output of the piezoelectric element attached to the opposite side of the optical member 4 is abnormal, it is determined that the optical member 4 is abnormal. . Then, the process proceeds to step S221.

  In step S221, since it is determined in step S220 that the optical member 4 is abnormal, the optical member 4 may be broken, and a correct image may not be captured. For this reason, processing for prohibiting the subsequent photographing operation is performed, and an abnormal state is recorded in a memory (not shown) or the like. In addition, an external display device (not shown) displays that the photographing optical system is abnormal and cannot be photographed, and the process proceeds to step S209 to end the test drive.

  Next, in step S222, since the drive signal to the actually driven piezoelectric element is abnormal, abnormalities in the drive circuit, detection circuit, piezoelectric element, etc. are assumed. For this reason, the foreign substance removal operation cannot be performed normally, but unlike the case of proceeding to step S220, it is considered that there is no problem with the photographing optical system, so it is determined that photographing can be performed. The fact that this foreign matter removal drive system is in an abnormal state is recorded in a memory (not shown) or the like. At this time, driving for removing foreign matter is prohibited. Further, it is displayed on the external display device (not shown) that the photographing is possible but the foreign matter removing operation cannot be performed, and the process proceeds to step S209 to end the test drive.

  Next, a specific detection signal in step 205 will be described with reference to FIG.

  In FIG. 14, the horizontal axis 1301 indicates the drive frequency, the vertical axis 1302 indicates the output voltage of the detection circuits 111 and 112, and 1303 indicates the change of the output voltage of the detection circuits 111 and 112 with respect to the drive frequency. Reference numeral 1303 indicates how the output voltages of the detection circuits 111 and 112 change in accordance with the change of the driving frequency. Here, when drive signals are output from the drive circuits 9 and 10, since the detection circuits 111 and 112 detect the output signals of the drive circuits 9 and 10, a constant output is output regardless of the drive frequency. It will be.

  Reference numeral 1304 denotes the level of the determination reference value in step S205. If it is equal to or higher than this determination level, it is determined that the outputs of the detection circuits 111 and 112 are normal. to decide.

  FIG. 15 shows a case where there is an abnormality in the drive circuit 9 or the drive circuit 10, and shows a state where the output voltages of the detection circuits 111 and 112 are lower than the determination level 1304 as indicated by 1305. ing.

  Step S218 is a step of determining an abnormality of the drive circuit 10, but the abnormality detection can be performed by the output voltage of the detection circuit 112 as in the case of step S205 (FIGS. 14 and 15).

  Next, a specific detection signal in step S219 will be described.

  In FIG. 16, 1306 operates only the drive circuit 10 to drive only the piezoelectric element 6, and detects the vibration state of the optical member 4 by the piezoelectric element 5 and the detection circuit 111. The detection signal is shown. Since this signal is a signal indicating the vibration state of the optical member 4, the output level is often lower than the signal in step S218. For this reason, the determination level indicated by 1307 is lower than the determination level in step S218.

  In FIG. 17, 1308 is an example of an abnormal signal, and shows a case where the vibration of the optical member 4 is smaller than a predetermined amplitude for some reason. In this case, the detection signal of the detection circuit 111 also has a low value, and an abnormality is detected. Further, when the optical member 4 is damaged, the detection signal is almost “0”, and an abnormality can be detected.

  As described above, the drive signal is detected for detecting the drive signal, and the drive signal is detected for detecting the vibration including the optical element. The vibration is detected and determined by the piezoelectric element.

  As described above, in the second embodiment, a driving piezoelectric element is used instead of the vibration detecting piezoelectric element. In other words, one of the two piezoelectric elements is driven and the non-driven piezoelectric element is used for detection, thereby detecting the vibration state of the optical element without providing a detection piezoelectric element. It becomes possible.

(Configuration of vibration unit)
Hereinafter, the imaging unit 400 will be described with reference to FIGS. 18 to 20. FIG. 18 is an exploded perspective view illustrating a schematic configuration inside the camera for explaining the peripheral structure of the imaging unit 400. A mirror box 205 and a shutter unit 32 are arranged in this order from the subject side on the subject side of the main body chassis 300 that is the skeleton of the camera body. An imaging unit 400 is disposed on the photographer side of the main body chassis 300. The image pickup unit 400 is adjusted and fixed so that the image pickup surface of the image pickup element 2 is spaced a predetermined distance and parallel to the attachment surface of the mount unit 202 as a reference to which the photographing lens unit is attached.

  FIG. 19 is an exploded perspective view showing the configuration of the imaging unit 400. The imaging unit 400 is roughly composed of a vibration unit 470, an elastic member 450, and an imaging element unit 500. Although details will be described later, the vibration unit 470 is fixed to the image pickup element unit 500 in such a manner as to sandwich the elastic member 450.

  First, the image sensor unit 500 will be described with reference to FIGS. 19 and 20. In the image sensor unit 500, 510 is a fixing member that holds the image sensor 2 and fixes the urging member 460 of the vibration unit 470. Reference numeral 520 denotes a circuit board on which an electric circuit of the imaging system is mounted, and is arranged on the photographer side of the fixing member 510. Reference numeral 530 denotes a shield case made of conductive metal or the like. Reference numeral 540 denotes a light shielding member in which an opening corresponding to the effective area of the photoelectric conversion surface of the image sensor 2 is formed, and is disposed on the subject side of the fixed member 510. An optical low-pass filter holding member 550 holds the optical low-pass filter 410.

  The fixing member 510 includes a positioning pin portion 510a for positioning with the biasing member 460 of the vibration unit 470, a screw hole 510b for fixing the circuit board 520 and the shield case 530 with screws, and a biasing member of the vibration unit 470. And a screw hole 510c for fixing 460 (fixing portion 460b) with a screw.

  20 is a cross-sectional view taken along line AA in FIG. The object-side surface of the light shielding member 540 is in contact with the optical low-pass filter 410, and the photographer-side surface is in contact with the cover glass 2 a of the image sensor 2. Double-sided tape is fixed to the subject side and the photographer side of the light shielding member 540, and the optical low-pass filter 410 is fixed and held on the cover glass 2a of the image sensor 2 by the double-sided tape of the light shielding member 540. As a result, the space between the optical low-pass filter 410 and the cover glass 2a of the image sensor 2 is sealed by the light shielding member 540, and a sealed space is formed to prevent entry of foreign matters such as dust. The piezoelectric element 5 is fixed to the image pickup element 2 side of the optical member (infrared cut filter) 4 as shown in the figure.

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

  The optical low-pass filter holding member 550 is fixed to the cover glass 2 a of the image pickup device 2 with the double-sided tape of the light shielding member 540. The optical low-pass filter 410 is positioned at the opening of the optical low-pass filter holding member 550, and is fixed and held on the light shielding member 540 with double-sided tape.

1 is a block diagram of a single-lens reflex digital camera according to a first embodiment of the present invention. It is a figure which shows the external appearance of the single-lens reflex digital camera of 1st Embodiment. It is the enlarged view which looked at the vicinity of the image sensor shown in FIG. 1 from the upper surface. It is a figure which shows the state which looked at the part of the optical member of FIG. 3 from the image pick-up element side, and the peripheral circuit of a piezoelectric element. It is a block diagram which shows the structure of the control circuit which controls a piezoelectric element and a detection piezoelectric element. It is a flowchart which shows the operation | movement regarding the vibration control of the optical member of a camera control part. It is a figure which shows the state which looked at the part of the optical member of FIG. 3 from the image pick-up element side in 2nd Embodiment, and the peripheral circuit of a piezoelectric element. It is a block diagram which shows the structure of the control circuit which controls a piezoelectric element. It is a flowchart which shows the operation | movement regarding the vibration control of the optical member of a camera control part. It is a figure which shows the change with respect to the drive frequency of the output voltage of a detection circuit. It is a figure which shows the output of a detection circuit when there is abnormality in a drive circuit. It is a figure which shows the detection signal at the time of operating the drive circuit of one side, and detecting the vibration condition of an optical member with the piezoelectric element for detection and detection circuit of an other side. It is a figure which shows an example of an abnormal signal. It is a figure which shows the change with respect to the drive frequency of the output voltage of a detection circuit. It is a figure which shows the output of a detection circuit when there is abnormality in a drive circuit. It is a figure which shows the detection signal at the time of operating the drive circuit of one side, and detecting the vibration condition of an optical member from the piezoelectric element and detection circuit of an other side. It is a figure which shows an example of an abnormal signal. It is a disassembled perspective view which shows schematic structure inside the camera for demonstrating the periphery structure of an imaging unit. It is a disassembled perspective view which shows the structure of an imaging unit. It is sectional drawing which follows the AA line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shooting lens unit 2 Image pick-up element 4 Optical member 5,6 Piezoelectric element 7,8 Piezoelectric element for detection 9,10 Drive circuit 11,12 Detection circuit 14 Oscillation circuit 15 Power supply circuit

Claims (8)

An image sensor that photoelectrically converts a subject image;
An optical member disposed in front of the image sensor;
First and second piezoelectric elements respectively disposed at both ends of the optical member;
First and second driving means for independently exciting and driving the first and second piezoelectric elements;
Detection means comprising first and second detection piezoelectric elements disposed adjacent to the first and second piezoelectric elements, respectively, for detecting vibrations of the optical member;
The first piezoelectric element is vibrated to vibrate the optical member and the second detection piezoelectric element is used to detect vibration of the optical member, or the second piezoelectric element is vibrated. The first and second drive means and the detection means are controlled so as to vibrate and vibrate the optical member and to detect vibration of the optical member using the first detection piezoelectric element. 1 control means;
An imaging apparatus comprising: The first piezoelectric element is vibrated to vibrate the optical member, and the vibration of the optical member is detected using the first detecting piezoelectric element, or the second piezoelectric element is vibrated. The first and second drive means and the detection means are controlled to vibrate to vibrate the optical member and to detect vibration of the optical member using the second detection piezoelectric element. Two control means,
2. The imaging according to claim 1, wherein the operation of the imaging apparatus is made different between a case where an abnormality is detected by the first control unit and a case where an abnormality is detected by the second control unit. apparatus.   When an abnormality is detected by the first control means, the photographing operation is prohibited, and when an abnormality is detected by the second control means without being detected by the first control means. The imaging apparatus according to claim 2, wherein vibration of the first and second piezoelectric elements for removing foreign matter is prohibited without prohibiting a photographing operation.   Third control means for controlling the first and second drive means so that both the first and second piezoelectric elements are driven to vibrate when removing the foreign matter adhering to the optical member. The imaging apparatus according to claim 1, further comprising: An image sensor that photoelectrically converts a subject image;
An optical member disposed in front of the image sensor;
First and second piezoelectric elements respectively disposed at both ends of the optical member;
First and second driving means for independently exciting and driving the first and second piezoelectric elements;
First detection means connected between the first piezoelectric element and the first driving means for detecting an output signal output from the first piezoelectric element when the first piezoelectric element vibrates. When,
Second detection means connected between the second piezoelectric element and the second driving means, and detecting an output signal output from the second piezoelectric element when the second piezoelectric element vibrates. When,
The first piezoelectric element is vibrated and vibrated to vibrate the optical member, and the second detection means is used to detect the output signal output from the second piezoelectric element, or the second First control means for vibrating the optical element to vibrate the optical member and detecting the output signal output from the first piezoelectric element using the first detection means;
An imaging apparatus comprising: The first piezoelectric element is vibrated to vibrate the optical member, and the output signal output from the first piezoelectric element is detected using the first detection means, or the second The first and second piezoelectric elements are vibrated to vibrate the optical member and detect the output signal output from the second piezoelectric element using the second detecting means. A second control means for controlling the drive means and the first and second detection means,
6. The imaging according to claim 5, wherein the operation of the imaging device is made different between when the abnormality is detected by the first control unit and when the abnormality is detected by the second control unit. apparatus.   When an abnormality is detected by the first control means, the photographing operation is prohibited, and when an abnormality is detected by the second control means without being detected by the first control means. The imaging apparatus according to claim 6, wherein excitation of the first and second piezoelectric elements for removing foreign matter is prohibited without prohibiting a photographing operation.   Third control means for controlling the first and second drive means so that both the first and second piezoelectric elements are driven to vibrate when removing the foreign matter adhering to the optical member. The imaging apparatus according to claim 5, further comprising:

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