JP2018025599A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress power consumption while removing foreign matter such as dust sticking on a surface of each optical filter by vibrating two optical filters arranged on subject sides of two imaging elements by piezoelectric elements, respectively.SOLUTION: An imaging apparatus comprises: a half-transmissive mirror 6 which transmits and guides subject luminous flux passed through a photography optical system to an imaging element 33 and also reflects and guides part of the subject luminous flux to an imaging element 34; optical filters 410, 510 arranged on subject sides of the imaging elements 33, 34 differing in pixel pitch from each other; vibrating elements 430, 530 exciting the optical filters 410, 510 to vibrate so as to remove foreign matter sticking on the optical filters 410, 510; and control means 101 for controlling driving of the vibrating elements 430, 530. The control means 101 controls the driving of the vibrating elements 430, 530 so that the electric power that the vibrating element 530, exciting the optical filter 510 to vibrate and arranged on the subject side of the imaging element 34 on the side where the pixel pitch is larger, consumes is smaller than the electric power that the other vibrating element 430 consumes.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an imaging apparatus such as a digital camera, and more particularly to an improvement in technology for removing foreign matters such as dust attached to an optical filter.

  Some imaging devices such as a digital camera divide a subject image into two by a semi-transparent mirror, take a still image with a first imaging device, and take a moving image with a second imaging device (Patent Document 1). By the way, when a foreign substance such as dust adheres to the surface of an optical filter such as an optical low-pass filter or an infrared absorption filter arranged on the subject side of the image sensor, the attached part becomes a black dot and appears in the photographed image. The appearance of will decline. In particular, in a digital single-lens reflex camera with interchangeable lenses, there is a high possibility that foreign matters such as dust will enter the camera body from the opening of the lens mount and adhere to the optical filter during lens replacement.

  Accordingly, the optical filter disposed on the subject side of the first image sensor and the optical filter disposed on the subject side of the second image sensor are each vibrated by a piezoelectric element, so that dust attached to the surface of each optical filter A technique for removing foreign substances has been proposed (Patent Document 2).

JP 2014-122957 A JP 2007-47198 A

  However, in Patent Document 1 described above, since two optical filters are vibrated by applying a common voltage to the two piezoelectric elements, twice the power consumption is required as compared with the case of vibrating one optical filter. . When the power consumption increases, the camera becomes larger as the number of images taken by the camera decreases and the drive circuit elements increase in size.

  Therefore, the present invention reduces power consumption while removing two foreign filters such as dust adhering to the surface of each optical filter by vibrating the two optical filters respectively disposed on the subject side of the two image sensors with piezoelectric elements. An object of the present invention is to provide an imaging device that can be suppressed.

  In order to achieve the above object, the present invention provides a mirror that transmits a subject light flux that has passed through a photographing optical system and guides it to the first image sensor, and reflects a part of the subject light flux to guide the second image sensor. An image pickup apparatus comprising: a first optical filter disposed on a subject side of the first image pickup element; and a first optical filter that excites vibration to the first optical filter so as to remove foreign matters attached to the first optical filter. 1 vibration element, 2nd optical filter arrange | positioned at the to-be-photographed object side of the said 2nd image pick-up element, and 2nd vibration which excites a vibration to the said 2nd optical filter in order to remove the foreign material adhering to the said 2nd optical filter And a control means for controlling driving of the first vibration element and the second vibration element. The first image pickup element and the second image pickup element have different pixel pitches, and the control Means Of the first vibrating element and the second vibrating element, the power consumed by the vibrating element that excites vibrations in the optical filter disposed on the subject side of the imaging element having the larger pixel pitch is consumed by the other vibrating element. The driving of the first vibration element and the second vibration element is controlled so as to be smaller than the electric power to be generated.

  According to the present invention, power consumption is reduced while removing two foreign filters such as dust attached to the surface of each optical filter by vibrating the two optical filters respectively disposed on the subject side of the two image pickup devices with the piezoelectric elements. Can be suppressed.

1 is a block diagram illustrating a system configuration example of a digital camera which is a first embodiment of an imaging apparatus of the present invention. It is the disassembled perspective view which showed the structure of the 1st imaging unit roughly. It is a graph which shows the relationship between the frequency of two vibration modes excited by the optical low-pass filter of a 1st imaging unit, and an amplitude. It is a figure which shows the vibration mode shape excited by the optical low-pass filter of a 1st imaging unit, and the voltage applied to the piezoelectric element of a 1st imaging unit. It is the disassembled perspective view which showed the structure of the 2nd imaging unit roughly. It is a graph which shows the relationship between the frequency and amplitude of two vibration modes excited by the optical low-pass filter of a 2nd imaging unit. It is a figure which shows the voltage applied to the vibration mode shape excited by the optical low-pass filter of a 2nd imaging unit, and the piezoelectric element of a 2nd imaging unit. It is a timing chart figure explaining the drive sequence of the foreign substance removal of two optical low-pass filters. It is a flowchart explaining the operation | movement which removes foreign materials, such as dust adhering to the surface of two optical low-pass filters. In the digital camera which is 2nd Embodiment of the imaging device of this invention, it is a graph which shows the relationship between the frequency and amplitude of two vibration modes excited by the optical low-pass filter of a 1st imaging unit. It is a figure which shows the vibration mode shape excited by the optical low-pass filter of a 1st imaging unit, and the voltage applied to the piezoelectric element of a 1st imaging unit. It is a graph which shows the behavior in each time phase of the optical low-pass filter of the 1st image pick-up unit at the time of exchanging two vibration modes at the same time phase. It is a graph which shows the behavior in each time phase of the optical low-pass filter of the 1st image pick-up unit at the time of exchanging two vibration modes at the same time phase. FIG. 10 is a flowchart illustrating a foreign matter removing operation of two optical low-pass filters when the camera is turned on in a digital camera that is the third embodiment of the imaging apparatus of the present invention. FIG. 15 is a timing chart schematically showing a driving sequence of each piezoelectric element when removing both foreign substances of two optical low-pass filters in step S1409 of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram illustrating a system configuration example of a digital camera which is a first embodiment of an imaging apparatus of the present invention.

  In the digital camera of this embodiment, as shown in FIG. 1, an interchangeable lens unit 200 is detachably mounted on the subject side of the camera body 100.

  First, the lens unit 200 will be described. In FIG. 1, the lens control circuit 202 receives the control signal from the MPU 101 of the camera body 100 and drives the photographing lens 201 and the diaphragm 205 via the AF driving circuit 203 and the diaphragm driving circuit 204. In FIG. 1, only one photographing lens 201 is shown for convenience, but in reality, the photographing lens 201 includes a photographing optical system including a number of lens groups such as a focus lens.

  The AF drive circuit 203 includes a stepping motor, for example, and changes the position of the focus lens of the photographing lens 201 in the optical axis direction under the control of the lens control circuit 202, thereby causing the imaging device 33 and the imaging device 34 of the camera body 100 to have a subject. Focus the luminous flux. The aperture driving circuit 204 is an aperture mechanism such as an auto iris, and changes the aperture amount of the aperture 205 under the control of the lens control circuit 202.

  Next, the camera body 100 will be described. In FIG. 1, a microcomputer (hereinafter referred to as MPU) 101 controls the entire digital camera. The MPU 101 is connected to a focus driving circuit 103, a shutter driving circuit 104, an image signal processing circuit 105, a switch sensor circuit 106, and a piezoelectric element driving circuit 111. These circuits operate under the control of the MPU 101.

  The MPU 101 communicates with the lens control circuit 202 of the lens unit 200 via the mount contact portion 21. When the lens unit 200 is connected, the MPU 101 receives a signal via the mount contact portion 21 to determine that the lens unit 200 can communicate with the lens control circuit 202 of the lens unit 200.

  The semi-transmissive mirror 6 is fixed to a mirror box (not shown) or the like while being held at an angle of 45 degrees with respect to the optical axis of the lens unit 200, and divides the subject luminous flux into two. Specifically, the subject light flux that has passed through the photographing lens 201 is reflected and guided to the image sensor 34, and part of the light is transmitted to the image sensor 33. The image sensor 33 corresponds to an example of a first image sensor of the present invention, and the image sensor 34 corresponds to an example of a second image sensor of the present invention.

  The shutter unit 32 is constituted by, for example, a mechanical focal plane shutter, and when in shooting standby, the shutter front curtain is in the light shielding position and the shutter rear curtain is in the exposure position. At the time of shooting, the shutter front curtain performs exposure travel in which the shutter front curtain moves from the light shielding position to the exposure position, thereby passing the subject light flux and guiding it to the image sensor 33. In addition, the shutter unit 32 performs a light-shielding traveling in which the shutter rear curtain moves from the exposure position to the light-shielding position after the set exposure time (shutter time) has elapsed, thereby completing the photographing of one image data. To do. The shutter unit 32 is controlled by a shutter drive circuit 104 that receives a control command from the MPU 101.

  The first imaging unit 400 is configured by unitizing components including the optical low-pass filter 410, the piezoelectric elements 430a and 430b, and the imaging element 33. The imaging device 33 is an imaging device such as a CMOS sensor or a CCD sensor that captures a high-definition still image, and outputs an analog image signal by photoelectrically converting the subject image formed through the semi-transmissive mirror 6. To do. The optical low-pass filter 410 corresponds to an example of the first optical filter of the present invention, and the piezoelectric elements 430a and 430b correspond to an example of the first vibration element of the present invention.

  The piezoelectric elements 430 a and 430 b are single-plate piezoelectric elements such as piezoelectric elements, for example, and are vibrated by the piezoelectric element driving circuit 111 that has received a control signal from the MPU 101 and transmit the vibration to the optical low-pass filter 410.

  The second imaging unit 500 is configured by unitizing components including the optical low-pass filter 510, the piezoelectric elements 530a and 530b, and the imaging element 34. The imaging device 34 is an imaging device such as a CMOS sensor or a CCD sensor that captures a moving image, and outputs an analog image signal by photoelectrically converting a subject image reflected and imaged by the semi-transmissive mirror 6. The optical low-pass filter 510 corresponds to an example of the second optical filter of the present invention, and the piezoelectric elements 530a and 530b correspond to an example of the second vibration element of the present invention.

  The piezoelectric elements 530 a and 530 b are single-plate piezoelectric elements such as piezoelectric elements, for example, and are vibrated by the piezoelectric element driving circuit 111 that has received a control signal from the MPU 101, and transmit the vibration to the optical low-pass filter 510.

  In addition, since a moving image generally does not require a resolution as high as that of a still image, the image pickup device 34 that picks up a moving image has a larger pixel pitch than the image pickup device 33 of the first image pickup unit 400 that picks up a still image. Yes. In addition, a mechanical shutter unit is not disposed on the imaging optical axis of the image sensor 34, and exposure adjustment is performed by an electronic shutter of the image sensor 34 itself.

  Furthermore, the effective shooting area of the image sensor 34 that captures a moving image is smaller than the effective shooting area of the image sensor 33 that captures a still image. For example, the image sensor 33 is a full-size effective area, and the image sensor 34 is an APS-C effective area. Thereby, the thickness of the upper part of the camera body 100 (above the semi-transparent mirror 6) in the thickness direction (the optical axis direction of the photographing lens 201) can be reduced, which can contribute to downsizing of the camera.

  The imaging device 34 includes a focus detection pixel including at least one pair of photoelectric conversion units for receiving the pupil-divided light beam, and performs phase difference type focus detection. The focus detection signal output from the image sensor 34 is supplied to the focus drive circuit 103, converted into a subject image signal, and then transmitted to the MPU 101.

  The MPU 101 performs focus detection calculation by the phase difference detection method based on the received subject image signal. Specifically, the MPU 101 calculates the defocus amount and direction using the subject image signal, and in accordance with the calculated defocus amount and direction, the focus of the photographic lens 201 via the lens control circuit 202 and the AF drive circuit 203 is calculated. Move the lens to the in-focus position.

  In addition, the MPU 101 converts the image signal output from the image sensor 34 into a luminance signal, and calculates an exposure value based on the luminance signal. Note that the above-described focus detection pixels may be provided in the image sensor 33 to perform phase difference focus detection. Alternatively, the image signal output from the image sensor 33 may be converted into a luminance signal, and the exposure value may be calculated based on the luminance signal.

  The image signal processing circuit 105 performs A / D conversion processing on the analog image signals output from the image sensor 33 and the image sensor 34, and further performs noise removal processing and gain adjustment processing on the obtained digital image data. Various image processing such as these are executed. Then, the image signal processing circuit 105 drives the display drive circuit 109 to display the image data after the image processing on the in-finder display monitor 17 and the display monitor 19. In the present embodiment, image data obtained by the image sensor 33 is displayed on the display monitor 19 during still image shooting, and image data obtained by the image sensor 34 is displayed on the display monitor 19 during moving image shooting.

  The photographer can observe the subject image displayed on the in-finder display monitor 17 through the finder eyepiece window 18. In the present embodiment, the image data obtained by the image sensor 34 is displayed on the in-finder display monitor 17, but the image data obtained by the image sensor 33 may be displayed on the in-finder display monitor 17.

  The switch sensor circuit 106 transmits to the MPU 101 an input signal input by the photographer operating the setting operation dial 8, the shooting mode setting dial 14, the main SW 43, the cleaning mode operation member 44, the still image / moving image switching SW 45, and the like. To do. The cleaning mode operation member 44 is a user interface for instructing removal of foreign matters such as dust adhering to the surfaces of the optical low-pass filter 410 and the optical low-pass filter 510. The photographer can perform the operation of removing the foreign matters attached to the optical low-pass filters 410 and 510 by operating the cleaning mode operation member 44.

  Next, the first imaging unit 400 will be described in detail with reference to FIG. FIG. 2 is an exploded perspective view schematically showing the configuration of the first imaging unit 400. As shown in FIG. 2, the optical low-pass filter 410 arranged on the subject side of the image sensor 33 is formed in a rectangular shape by a single birefringent plate made of quartz, and the point image separation direction is the left-right direction of the camera ( The direction of the arrow A in the figure, the direction orthogonal to the vibration node). The optical low-pass filter 410 has a peripheral portion in which a pair of piezoelectric elements 430a and 430b are arranged on both sides outside the optical effective region, and the direction orthogonal to the imaging optical axis center (camera left-right direction) is symmetric. . The surface of the optical low-pass filter 410 is provided with an optical coating such as infrared cut and antireflection.

  The piezoelectric elements 430a and 430b have a strip-like outer shape, and are bonded to the vicinity of two sides facing each other in the width direction (left and right direction of the camera) of the surface of the optical low-pass filter 410 on the imaging element 33 side. More specifically, the piezoelectric elements 430 a and 430 b are disposed and pasted at the periphery of the optical low-pass filter 410 so that the long sides of the piezoelectric elements 430 a and 430 b are parallel to the short sides on both sides of the optical low-pass filter 410 in the width direction. Worn. The optical low-pass filter 410 is vibrated in a wave shape so that a plurality of abdomen and nodes parallel to the side are generated.

  When a periodic voltage is applied from the piezoelectric element driving circuit 111 to the piezoelectric elements 430a and 430b via a flexible printed board (not shown), the piezoelectric element 430 expands and contracts, and the optical low-pass filter 410 also periodically moves accordingly. Bending deformation occurs. The optical low-pass filter 410 is held by a resin or metal filter holding member 420, and the filter holding member 420 is fixed to the element holding member 470 that holds the image sensor 33 with screws or the like.

  The biasing member 440 biases the optical low-pass filter 410 in the direction of the image sensor 33 and is locked to the filter holding member 420. The biasing member 440 is grounded to the ground (GND) of the camera body 100, and the surface of the optical low-pass filter 410 is also grounded to the ground of the camera body 100. Thereby, electrostatic adhesion such as dust on the surface of the optical low-pass filter 410 can be suppressed.

  The elastic member 450 is formed in a rectangular frame shape by an elastic material having a substantially circular cross section, and is held in close contact with the optical low-pass filter 410 and the filter holding member 420. This adhesion force is determined by the urging force of the urging member 440 in the direction of the image sensor 33. The elastic member 450 may be formed using a rubber material, or may be formed using a urethane foam such as poron. Accordingly, the optical low-pass filter 410 is held so as to be able to vibrate while being sandwiched between the biasing member 440 and the elastic member 450.

  The optical member 460 includes a phase plate (depolarization plate), an infrared cut filter, and a birefringent plate having a point image separation direction B that is 90 ° different from the point image separation direction A of the optical low-pass filter 410. And bonded and fixed to the filter holding member 420. The element holding member 470 has a rectangular opening, and is fixed to the camera body 100 with screws or the like in a state where the imaging element 33 is fixed from the back side so that the imaging element 33 is exposed in the opening. .

  The mask 480 is for preventing extra light from entering the imaging device 33 from entering the imaging optical path. The mask 480 is sandwiched between the filter holding member 420 and the imaging device 33 and held in close contact therewith. The element biasing member 490 includes a pair of left and right leaf springs, is fixed to the element holding member 470 with screws or the like, and presses the image sensor 33 against the element holding member 470.

  Next, vibration of the optical low-pass filter 410 will be described with reference to FIGS. In the present embodiment, bending standing wave vibration is generated in the optical low-pass filter 410, and the foreign matter attached to the optical low-pass filter 410 is removed in the normal direction of the optical low-pass filter 410.

  FIG. 3 is a graph showing the relationship between the frequency and amplitude of two vibration modes excited by the optical low-pass filter 410 by the piezoelectric elements 430a and 430b. As shown in FIG. 3, the m-th order vibration mode is excited at the frequency indicated by f (m), and the m + 1-order vibration mode is excited at the frequency indicated by f (m + 1). Here, by setting the frequency f of the voltage applied to the two piezoelectric elements 430a and 430b to f = f (m) and f = f (m + 1), respectively, resonance of the m-order mode and the m + 1-order mode is utilized. be able to.

  FIG. 4A and FIG. 4B are diagrams showing m-order and m + 1-order vibration mode shapes when m is an odd number, and voltages applied to the piezoelectric elements 430a and 430b. 4A and 4B show a case where m = 9 as an example when m is an odd number. As shown in FIG. 4A, the generated vibration is a bending standing wave vibration in which a plurality of nodes appear at equal intervals in the direction parallel to the longitudinal direction of the piezoelectric elements 430a and 430b (in the same direction) in each mode. It is. In FIG. 4B, the amplitude of the AC voltage applied to the piezoelectric elements 430a and 430b in each mode is represented by a real number component and an imaginary number component.

  In FIG. 4B, (1) shows the AC voltage in the mth order vibration mode, and (2) shows the AC voltage in the m + 1st order vibration mode. Here, the voltage of each mode is normalized by the amplitude of the m-th order vibration mode, and the m-order: AA and m + 1-order: AA shown in FIG. 4B are the m-order vibration mode and the m + 1-order vibration mode. Are driven at the same voltage.

  By combining the applied voltages (1) and (2), the foreign matter adhering to the surface of the optical low-pass filter 410 is removed. Specifically, the m + 1 order vibration mode is generated in the optical low-pass filter 410 at the frequency f (m + 1), and then the mth order vibration mode is generated at the frequency f (m). Thereby, the foreign matter adhering to the surface of the optical low-pass filter 410 can be removed and removed.

  The reason for using two vibration modes is to screen out foreign matters remaining on the vibration nodes in one vibration mode in the other vibration mode in which the nodes do not occur in the same region. Therefore, when the vibration modes of the odd and even nodes adjacent to each other are used, the node is not generated in the same region, and the foreign matter removing effect is enhanced. Furthermore, the foreign matter removal effect is further enhanced by repeating the combination of the two vibration modes a plurality of times.

  Note that the number of vibration modes to be used is not limited to two, and the frequencies f = f (m), f (m + 1), and f (m + 2) may be combined with three adjacent vibration modes, or more than that. You may combine a vibration mode. Further, considering the resonance frequency variation α caused by the thickness variation of the optical low-pass filter 410 and the like: α, the frequency may be gradually changed in the range Δf1 from f (m + 1) + α to f (m) −α ( (See FIG. 3). This eliminates the need for individual adjustment of the frequencies f = f (m) and f (m + 1) without removing the resonance frequencies f = f (m) and f (m + 1), and simplifies and assembles the electrical system. The adjustment process can be reduced.

  Next, the second imaging unit 500 will be described in detail with reference to FIG. FIG. 5 is an exploded perspective view schematically showing the configuration of the second imaging unit 500. The optical low-pass filter 510 disposed on the subject side of the image sensor 34 is composed of a single rectangular birefringent plate made of quartz. The optical low-pass filter 510 has peripheral portions for arranging the pair of piezoelectric elements 530a and 530b on both sides in the width direction outside the optical effective area, and is symmetrically arranged in a direction orthogonal to the center of the photographing optical axis (camera left-right direction). Has been. Similar to the optical low-pass filter 410, the optical low-pass filter 510 is vibrated in a wave shape so that a plurality of abdomen and nodes parallel to the side are generated.

  A flexible printed board (not shown) is connected to the piezoelectric elements 530a and 530b. A periodic voltage is applied from the piezoelectric element driving circuit 111 to the piezoelectric elements 530a and 530b via the flexible printed circuit board, whereby the piezoelectric elements 530a and 530b expand and contract, and the optical low-pass filter 510 is also periodically generated accordingly. Bending deformation occurs.

  The areas of the piezoelectric elements 530a and 530b are smaller than the areas of the piezoelectric elements 430a and 430b of the second imaging unit 500. By making the area of the piezoelectric elements 530a and 530b smaller than the area of the piezoelectric elements 430a and 430b, the capacitance is reduced, the current consumption with respect to the applied voltage is reduced, and the power consumption is suppressed. On the other hand, when the current consumption of the piezoelectric elements 530a and 530b is lowered, the foreign matter removing ability of the optical low-pass filter 510 is deteriorated.

  However, the appearance of the foreign matter on the image sensor has a relationship of “in inverse proportion to the square root of the pixel pitch ratio”. As described above, the image sensor 34 has a larger pixel pitch than the image sensor 33, and thus the image sensor 33. Smaller foreign objects are less visible. For this reason, the foreign matter removing ability is allowed even if the piezoelectric elements 530a and 530b are somewhat inferior to the piezoelectric elements 430a and 430b.

  In order to reduce the drive area of the piezoelectric elements 530a and 530b, as shown in FIG. 5, the drive area of each of the piezoelectric elements 530a and 530b may be reduced, or one of the piezoelectric elements 530a and 530b is omitted. You may do it. As described above, since the imaging element 34 has a smaller effective shooting area than the imaging element 33, the area of the optical low-pass filter 510 can be designed to be smaller than that of the optical low-pass filter 410.

  The piezoelectric elements 530a and 530b can also be reduced according to the ratio of the effective shooting area of the image sensor 34 to the effective shooting area of the image sensor 33. The driving area can be reduced. That is, the ratio of the drive area of the piezoelectric elements 530a and 530b to the area of the optical low-pass filter 510 can be designed to be smaller than the ratio of the drive area of the piezoelectric elements 430a and 430b to the area of the optical low-pass filter 410. It is. Accordingly, it is possible to maintain the necessary and sufficient foreign matter removing capability for the optical low-pass filter 510 while suppressing the power consumption of the piezoelectric elements 530a and 530b.

  Further, it is desirable that the point image separation direction of the optical low-pass filter 510 is a vertical direction C (a direction parallel to the vibration node) which is the front-rear direction of the camera. In the vibration method of the optical low-pass filter 510 of the present embodiment, the point image separation direction has a greater vibration sharpness (Q value) in the horizontal direction and a larger amplitude at resonance, which is useful for removing foreign matters. It is advantageous.

  However, as described above, the image pickup element 34 has a larger pixel pitch than the image pickup element 33 and the point image separation width is increased accordingly, so that the optical low-pass filter 510 is thicker than the optical low-pass filter 410. Yes. For this reason, when the optical low-pass filter 510 is vibrated in the same vibration mode as the optical low-pass filter 410 (the number of vibration nodes is the same), the frequency increases, and as a result, the power consumption of the piezoelectric elements 530a and 530b is reduced. It gets bigger.

  Therefore, by making the point image separation direction of the optical low-pass filter 510 the vertical direction C, the Young's modulus in the long side direction of the optical low-pass filter 510 is reduced, and the same vibration mode as that of the optical low-pass filter 410 is excited at a low frequency. Is possible. By doing so, the power consumption of the piezoelectric elements 530a and 530b can be suppressed.

  Note that, by setting the point image separation direction to the vertical direction C, the sharpness (Q value) of vibration is reduced and the foreign matter removal capability is inferior, but as described above, the image sensor 34 is the image sensor 33. Smaller foreign objects are less visible. For this reason, the optical low-pass filter 510 may be inferior in the foreign matter removing ability. Therefore, it is possible to maintain the necessary and sufficient foreign substance removing capability for the optical low-pass filter 510 while suppressing the power consumption of the piezoelectric elements 530a and 530b.

  The optical member 560 includes a phase plate (depolarization plate), an infrared cut filter, and a birefringent plate having a point image separation direction D that is 90 ° different from the point image separation direction C of the optical low-pass filter 510. And bonded and fixed to the filter holding member 520. Since other configurations are the same as those of the first imaging unit 400, the description thereof is omitted.

  As described above, the effective shooting area of the image pickup device 34 for moving image pickup is set smaller than the effective shooting area of the image pickup device 33 for still image pickup, and accordingly, the optical member 560 and the filter are set accordingly. The holding member 520 can also be set small. Therefore, the second imaging unit 500 is smaller than the first imaging unit 400 as a whole. Thereby, the thickness of the upper part of the camera body 100 (above the semi-transparent mirror 6) in the thickness direction (the optical axis direction of the photographing lens 201) can be reduced, which can contribute to downsizing of the camera.

  Next, the vibration of the optical low-pass filter 510 will be described with reference to FIGS. In the present embodiment, bending standing wave vibration is generated in the optical low-pass filter 510, and the foreign matter adhering to the optical low-pass filter 510 is removed in the normal direction of the optical low-pass filter 510.

  FIG. 6 is a graph showing the relationship between the frequency and amplitude of two vibration modes excited by the optical low-pass filter 510 by the piezoelectric elements 530a and 530b. As shown in FIG. 6, the nth order vibration mode is excited at the frequency indicated by f (n), and the n + 1st order vibration mode is excited at the frequency indicated by f (n + 1). Here, by setting the frequency f of the voltage applied to the piezoelectric elements 530a and 530b to f = f (n) and f = f (n + 1), respectively, the resonance of the n-order mode and the n + 1-order mode can be used. it can. Note that the vibration mode to be used is not limited to two as described above.

  Here, it is desirable that the resonance frequency f (n) of the optical low-pass filter 510 is set to be smaller than the resonance frequency f (m) of the optical low-pass filter 410. In general, since the force to repel small foreign matters increases in proportion to the square of the frequency, it is desirable to set the drive frequency of the piezoelectric elements 530a and 530b to be high. Electricity will also increase.

  Therefore, the power consumption of the piezoelectric elements 530a and 530b is suppressed by making f (n) smaller than f (m). In this case, the foreign matter removal capability of the optical low-pass filter 510 is inferior, but as described above, the imaging element 34 is less likely to see a foreign matter smaller than the imaging device 33, and therefore the foreign matter removal capability of the optical low-pass filter 510 is somewhat inferior. Is acceptable. Accordingly, it is possible to maintain the necessary and sufficient foreign matter removing capability for the optical low-pass filter 510 while suppressing the power consumption of the piezoelectric elements 530a and 530b.

  FIGS. 7A and 7B are diagrams showing n-order and n + 1-order vibration mode shapes when n is an odd number, and voltages applied to the piezoelectric elements 530a and 530b. As shown in FIG. 7, the piezoelectric elements 530a and 530b are driven with the same drive voltage BB in both the n-order vibration mode and the n + 1-order vibration mode.

  Here, the drive voltage BB of the piezoelectric elements 530a and 530b that vibrate the optical low-pass filter 510 is desirably smaller than the drive voltage AA of the piezoelectric elements 430a and 430b that vibrate the optical low-pass filter 410. In general, since the force for repelling small foreign matters increases in proportion to the amplitude, the foreign matter removing ability becomes higher when the driving voltage of the piezoelectric element is increased to increase the amplitude.

  However, when the driving voltage of the piezoelectric element is increased, the current value is increased correspondingly and the power consumption is increased. Therefore, the power consumption is suppressed by making the drive voltage BB of the piezoelectric elements 530a and 530b smaller than the drive voltage AA of the piezoelectric elements 430a and 430b. In this case, the foreign matter removing ability of the optical low-pass filter 510 is inferior. However, as described above, the image sensor 34 is less likely to see small foreign objects than the image sensor 33, and thus the foreign substance removal capability is allowed even if the optical low-pass filter 510 is slightly inferior to the optical low-pass filter 410. Therefore, the drive voltage BB of the piezoelectric elements 530a and 530b may be determined so that a necessary and sufficient foreign substance removing capability can be obtained for the optical low-pass filter 510.

  Further, as described above, since the imaging element 34 has a smaller photographing effective area than the imaging element 33, the area of the optical low-pass filter 510 can be designed to be smaller than that of the optical low-pass filter 410. Even if the voltage applied to the piezoelectric elements 530a and 530b is reduced by the amount corresponding to the reduction in the area, the same amplitude, that is, the same foreign matter removing ability can be realized.

  In addition, when the above-mentioned difficulty in seeing small foreign matters on the image sensor 34 is taken into consideration, the applied voltage to the piezoelectric elements 530a and 530b can be further reduced. That is, the voltage is determined so that the ratio of the applied voltage of the piezoelectric elements 530a and 530b to the area of the optical low-pass filter 510 is smaller than the ratio of the applied voltage of the piezoelectric elements 430a and 430b to the area of the optical low-pass filter 410. Is possible. Accordingly, it is possible to maintain the necessary and sufficient foreign matter removing capability for the optical low-pass filter 510 while suppressing the power consumption of the piezoelectric elements 530a and 530b.

  In addition, the frequency may be gradually changed in the range Δf2 from f (n) −β to f (n + 1) + β in consideration of the resonance frequency variation β that occurs due to the thickness variation of the optical low-pass filter 510 and the like. (See FIG. 6). This eliminates the need for individual adjustment of the frequencies f = f (n) and f (n + 1) without removing the resonance frequencies f = f (n) and f (n + 1), and simplifies and assembles the electrical system. The adjustment process can be reduced.

  Here, it is desirable that the gradual change directions of the driving frequencies of the optical low-pass filters 410 and 510 by the piezoelectric elements 430a and 430b and the piezoelectric elements 530a and 530b are different from each other. In the present embodiment, as shown in FIG. 3, the optical low-pass filter 410 gradually changes the drive frequency from f (m + 1) + α to f (m) −α, that is, from a high frequency to a low frequency. On the other hand, as shown in FIG. 6, the optical low-pass filter 510 gradually changes the driving frequency from f (n) −β to f (n + 1) + β, that is, from a low frequency to a high frequency.

  This is particularly effective when the vibrations of the optical low-pass filters 410 and 510 are simultaneously excited, but both are high if the direction of gradual change in the driving frequency of the piezoelectric elements 430a and 430b and the piezoelectric elements 530a and 530b is the same. The drive time at the frequency overlaps. For this reason, the total current consumption and the total power consumption of the piezoelectric elements 430a and 430b and the piezoelectric elements 530a and 530b are unnecessarily large. An increase in current consumption and power consumption leads to an increase in the size of the mounting element of the vibration drive circuit of the piezoelectric element, which hinders the reduction in size and weight of the camera.

  Therefore, the gradual change directions of the driving frequencies of the optical low-pass filters 410 and 510 by the piezoelectric elements 430a and 430b and the piezoelectric elements 530a and 530b are made different from each other, and the total consumption current and the total consumption power of both are averaged in the driving time. Thereby, it is possible to avoid unnecessarily increasing the current consumption and power consumption per unit time, and it is possible to avoid an increase in the size of the mounting element of the vibration drive circuit of the piezoelectric element.

  Next, with reference to FIG. 8, a drive sequence for removing foreign substances of the optical low-pass filters 410 and 510 by the piezoelectric elements 430a and 430b and the piezoelectric elements 530a and 530b will be described.

  FIG. 8A is a timing chart schematically showing a drive sequence of the piezoelectric elements 430a and 430b and the piezoelectric elements 530a and 530b when removing the foreign matter from the optical low-pass filters 410 and 510. FIG. In FIG. 8A, the vertical axis represents on / off of the drive signal, and the horizontal axis represents elapsed time. 8A shows a driving sequence for removing foreign matter of the optical low-pass filter 410 by the piezoelectric elements 430a and 430b, and the lower row shows a driving sequence for removing foreign matter of the optical low-pass filter 510 by the piezoelectric elements 530a and 530b. Represents.

  In order to remove the foreign matter adhering to the optical low-pass filter 410, first, the piezoelectric elements 430a and 430b are driven for a time of ΔT1 in the (1) m + 1st order vibration mode, wait for a predetermined time, and then (2) the mth order vibration. Drive in the mode for a time of ΔT1. Then, the driving of (1) and (2) is repeated once more. As a result, the total ΔT1total of driving times of the piezoelectric elements 430a and 430b (vibration time of the optical low-pass filter 410) is ΔT1total = 4 × ΔT1.

  On the other hand, in order to remove the foreign matter adhering to the optical low-pass filter 510, first, the piezoelectric elements 530a and 530b are driven for a time of ΔT2 in the (3) n-order vibration mode, and after waiting for a predetermined time, (4) n + 1-order. Is driven for a time ΔT2 in the vibration mode. Then, the driving of (3) and (4) is repeated once more. As a result, the total ΔT2total of driving times of the piezoelectric elements 530a and 530b (vibration time of the optical low-pass filter 510) is ΔT2total = 4 × ΔT2.

  And the drive start timing of each vibration mode of the optical low-pass filter 410 and the optical low-pass filter 510 is the same. Specifically, the drive start timings of (1) m + 1 order vibration mode and (3) n order vibration mode are the same, and (2) m order vibration mode and (4) n + 1 order vibration mode drive. The start timing is simultaneous.

  Here, the total driving time ΔT2total of the piezoelectric elements 530a and 530b for exciting the vibration of the optical low-pass filter 510 may be shorter than the total driving time ΔT1total of the piezoelectric elements 430a and 430b for exciting the vibration of the optical low-pass filter 410. desirable. In other words, it is desirable that ΔT1> ΔT2 when the drive times ΔT1 and ΔT2 of one vibration mode are compared. In general, the longer the time for exciting the vibration of the optical low-pass filter 510, the higher the foreign substance removal capability. However, if the driving time of the piezoelectric elements 530a and 530b is long, the power consumption increases accordingly.

  Therefore, the total drive time ΔT2total of the piezoelectric elements 530a and 530b is made shorter than the total drive time ΔT1total of the piezoelectric elements 430a and 430b, or the drive time ΔT2 of one vibration mode is made shorter than the drive time ΔT1. Thereby, the power consumption of the piezoelectric elements 530a and 530b is suppressed.

  In this case, the foreign matter removing ability of the optical low-pass filter 510 is inferior. However, as described above, since the imaging device 34 is less likely to see foreign matter smaller than the imaging device 33, some deterioration of the foreign matter removing capability is allowed. . Therefore, the total driving time ΔT2total of the piezoelectric elements 530a and 530b or the driving time ΔT2 of one vibration mode may be determined so that the necessary and sufficient foreign substance removing capability can be obtained for the optical low-pass filter 510. Accordingly, it is possible to maintain the necessary and sufficient foreign matter removing capability for the optical low-pass filter 510 while suppressing the power consumption of the piezoelectric elements 530a and 530b.

  FIG. 8B is a timing chart schematically showing a modification of the drive sequence of the piezoelectric elements 430a and 430b and the piezoelectric elements 530a and 530b when removing the foreign matter from the optical low-pass filters 410 and 510.

  In the driving sequence for removing foreign matter of the optical low-pass filter 510 by the piezoelectric elements 530a and 530b, in FIG. 8A, the number of times of driving in the (3) nth order and (4) n + 1st order vibration modes is two each. . On the other hand, FIG. 8B is different in that the number of times of driving in the (3) n-order and (4) n + 1-order vibration modes is one each.

  Even in this case, the total driving time ΔT2total (= 2 × ΔT2) of the piezoelectric elements 530a and 530b can be made shorter than the total driving time ΔT1total (= 4 × ΔT1) of the piezoelectric elements 430a and 430b. Therefore, it is possible to maintain the necessary and sufficient foreign substance removing capability for the optical low-pass filter 510 while suppressing the power consumption of the piezoelectric elements 530a and 530b. In FIG. 8B, the drive time ΔT1> ΔT2 for one vibration mode is satisfied, but ΔT1 = ΔT2 may be used. Also in this case, the relationship of the total driving time ΔT2total <ΔT1total is obtained, and the same effect can be obtained.

  In addition, although the drive start timings of the vibration modes of the optical low-pass filters 410 and 510 are the same, the drive start timing of the optical low-pass filter 510 may be delayed within a range in which both drive times overlap. For example, (3) the drive start timing of the piezoelectric elements 530a and 530b in the n-th vibration mode is set so that the (3) n-th vibration mode ends at the timing when the (m + 1) -th vibration mode ends. May be.

  Next, with reference to FIG. 9, an operation for removing foreign matters such as dust attached to the surfaces of the optical low-pass filters 410 and 510 will be described. The processing in FIG. 9 is executed by the MPU 101 after a program stored in a ROM (not shown) is expanded in a RAM (not shown).

  In FIG. 9, in step S901, the MPU 101 determines whether the camera SW is turned on in the main SW 43. When the power is turned on, the process proceeds to step S902. In step S902, the MPU 101 supplies power to each circuit shown in FIG. 1 to initialize the system, performs an on-operation of the camera system so that the camera can perform a photographing operation, and proceeds to step S903.

  In step S903, the MPU 101 determines whether or not the cleaning mode operation member 44 has been operated. If operated, the process proceeds to step S904, and if not operated, the process proceeds to step S905. In the present embodiment, the operation of the cleaning mode operation member 44 is instructed to shift to the cleaning mode. However, the operation is not limited to the mechanical operation member, and the transition to the cleaning mode is instructed by the touch panel of the display monitor 19 or the like. May be.

  In step S904, when the MPU 101 receives the cleaning mode start signal, the piezoelectric element driving circuit 111 generates a periodic voltage that excites the standing wave vibrations of the optical low-pass filters 410 and 510. Then, the MPU 101 applies the voltage generated by the piezoelectric element driving circuit 111 to the piezoelectric elements 430a and 430b and the piezoelectric elements 530a and 530b, and the process proceeds to step S905.

  At this time, the piezoelectric elements 430a and 430b and the piezoelectric elements 530a and 530b expand and contract according to the voltage applied by the piezoelectric element driving circuit 111, and cause the optical low-pass filters 410 and 510 to generate standing wave vibration. The drive sequence of each of the optical low-pass filters 410 and 510 executes the drive sequence described with reference to FIG. 8A or FIG. Thereby, the foreign material adhering to the surface of the optical low-pass filters 410 and 510 can be removed.

  In step S905, the MPU 101 performs a camera operation based on operation signals from the setting operation dial 8, the shooting mode setting dial 14, the still image / moving image switching SW 45, and other switches, and the process proceeds to step S906. The camera operation here is an operation for performing still image shooting / setting, moving image shooting / setting, or the like of a generally known camera, and detailed description thereof is omitted here.

  In step S906, the MPU 101 determines whether the main SW 43 has been turned off. If the power is turned off, the process proceeds to step S907. If the power is not turned off, the process returns to step S903. .

  In step S907, the MPU 101 executes the same cleaning mode as that in step S904, and then proceeds to step S908. In the cleaning mode executed here, parameters such as the driving frequency, driving time, and control method of the piezoelectric elements 430 and 530 may be different from those in step S904 in consideration of the power consumption and operation time of the camera.

  In step S908, the MPU 101 performs control for terminating each circuit, stores necessary information in the EEPROM 108 built in the MPU 101, performs a power-off operation to shut off power supply to each circuit, and performs processing. Exit. As described above, in this embodiment, the cleaning mode is executed not only at an arbitrary timing instructed by the photographer but also at a power-off timing. That is, after the camera is turned off, an operation for removing foreign matter adhering to the surfaces of the optical low-pass filters 410 and 510 is performed again, and then the camera system is turned off.

  Here, there are various kinds of foreign matters adhering to the surface of the optical low-pass filter, but generally, if left for a long time with foreign matters attached, it may be difficult to remove even if vibration is applied in the cleaning mode. . This is thought to be due to increased adhesion of liquid cross-linking force due to condensation due to changes in the environment (temperature and humidity), and adhesion due to repeated swelling and drying of foreign matter due to environmental changes. It is done.

  In addition, in an elastic material such as rubber, oil and fat contained in the rubber bleeds and adheres over time. Therefore, performing the cleaning mode at the timing of the camera's power-off operation is more likely than at the timing of the power-on operation after a long-term unused state that is likely to be in a state where it is difficult to remove foreign objects. Efficient and effective. In addition to executing the cleaning mode at the power-off operation timing, the cleaning mode may be executed at the power-on operation timing.

  As described above, in the present embodiment, when removing the foreign matter adhering to the surfaces of the optical low-pass filters 410 and 510 by vibration, the driving voltage of each piezoelectric element is maintained while maintaining the necessary foreign matter removal capability. The driving frequency, the driving time, and the like are different from each other. Thereby, the optical low-pass filters 410 and 510 disposed on the front side of the two image sensors 33 and 34 are respectively vibrated by the piezoelectric elements to remove foreign matters such as dust attached to the surfaces of the optical low-pass filters 410 and 510. However, power consumption can be suppressed. As a result, it is possible to reduce the size of the camera as the number of images taken by the camera increases and the size of the drive circuit element is reduced.

(Second Embodiment)
Next, a digital camera that is a second embodiment of the imaging apparatus of the present invention will be described with reference to FIGS. In the present embodiment, portions overlapping or corresponding to those in the first embodiment will be described with reference to the drawings and symbols.

  In the present embodiment, of the optical low-pass filters 410 and 510, vibration that conveys foreign matters such as dust attached to the optical low-pass filter 410 is generated in the optical low-pass filter 410. Specifically, the foreign matter adhered by driving the piezoelectric elements 430a and 430b bonded and fixed to the optical low-pass filter 410 to excite the optical low-pass filter 410 with two bending vibrations having different orders by shifting the time phase. Transport.

  FIG. 10 is a graph showing the relationship between the frequency and amplitude of the two vibration modes excited by the optical low-pass filter 410. As shown in FIG. 10, the mth order vibration mode is excited at the frequency indicated by f (m), and the m + 1st order vibration mode is excited at the frequency indicated by f (m + 1). Here, if the frequency f of the voltage applied to the piezoelectric elements 430a and 430b is set to f (m) <f <f (m + 1), both m-order mode and m + 1-order mode resonances can be used.

  When the frequency f is set to f <f (m), the mth-order resonance can be used, but it is difficult to increase the amplitude of the m + 1st-order mode because it is away from the f (m + 1) th-order resonance point. . When f (m + 1) <f, the amplitude increases only in the m + 1 order mode. In this embodiment, since both vibration modes are used, the frequency f is set in a range where f (m) <f <f (m + 1).

  FIGS. 11A and 11B are diagrams showing m-order and m + 1-order vibration mode shapes when m is an odd number, and voltages applied to the piezoelectric elements 430a and 430b. FIGS. 11A and 11B show a case where m = 9 as an example when m is an odd number. As shown in FIG. 11A, in each mode, a plurality of nodes appear at equal intervals in the direction parallel to the longitudinal direction of the piezoelectric elements 430a and 430b (in the same direction). In FIG. 11B, the amplitude and temporal phase of the AC voltage applied to the piezoelectric elements 430a and 430b in each mode are represented by a real component and an imaginary component.

  In FIG. 11B, (1) shows the m-order vibration mode AC voltage, (2) shows the m + 1-order vibration mode AC voltage, and (3) shows the m + 1-order vibration mode for 90 ° time. The AC voltage is shown with the phase shifted. Here, in order to obtain the same amplitude in the two vibration modes, where the amplitude ratio of the m-th vibration mode and the m + 1-order vibration mode with respect to an AC voltage of a certain frequency is A: 1, the voltage of each vibration mode is set to m-th order. Normalized by vibration mode amplitude. In order to simultaneously excite the m-th order vibration mode and the m + 1-order vibration mode whose time phase differs by 90 ° with respect to the optical low-pass filter 410, the AC voltages of (1) and (3) are added, and (4 An AC voltage as shown in FIG.

  Next, the behavior of the optical low-pass filter 410 when the two vibration modes are excited simultaneously will be described. As an example, consider the case where the 9th and 10th vibration modes are excited simultaneously.

  12 and 13 are graphs showing the behavior of the optical low-pass filter 410 at each time phase when two vibration modes are excited simultaneously with the time phase shifted by 90 °. The horizontal axis in the figure represents the position in the optical low-pass filter 410, and the values from the left end to the right end are represented by numerical values of 0 to 360. The long side direction of the optical low-pass filter 410 is X, the short side direction is Y, and the normal direction of the surface is Z.

  12 and 13, C represents the ninth-order vibration mode waveform, and D represents the tenth-order vibration mode waveform. Further, E in the figure represents a waveform obtained by synthesizing two vibration modes, that is, the actual amplitude of the optical low-pass filter 410. In the figure, F is the acceleration in the Z direction of the optical low-pass filter 410.

  The foreign matter adhering to the surface of the optical low-pass filter 410 is conveyed by receiving a force in the normal direction when the optical low-pass filter 410 is deformed. That is, when the curve F indicating the acceleration in the Z direction takes a positive value, the foreign matter is pushed out of the plane and receives a force in the normal direction of the curve E indicating the displacement of the optical low-pass filter 410 in this time phase.

  In the section indicated by rn (n = 1, 2, 3,...) In the figure, the foreign substance receives a force in the right direction (positive direction in the X direction). In the section indicated by ln (n = 1, 2, 3,...) In the figure, the foreign matter receives a force in the left direction (negative direction in the X direction). As a result, the foreign substance moves to a position indicated by Xn (n = 1, 2, 3,...). In this embodiment, Xn (n = 1, 2, 3,...) Moves in the positive direction of the X direction as the time phase advances, so that the foreign matter is conveyed in the positive direction of the X direction. .

  In general, when the carrier vibration and the standing wave vibration are compared, if the amplitude is the same, the carrier vibration has a higher ability to remove small foreign matters. This is because when the foreign matter adhered to the surface of the optical low-pass filter with a force such as liquid bridge force or van der Waals force is peeled off, the force in the oblique direction with a certain angle with respect to the normal is smaller than that in the normal direction. This is because the foreign matter can be peeled off.

  However, as described with reference to FIG. 10, since the drive frequency f is set in a range where f (m) <f <f (m + 1), the amplitude peak points f (m) and f (m + 1) Will vibrate with a small amplitude. In the standing wave vibration, the frequencies used are f (m) and f (m + 1). Therefore, the standing wave vibration has a larger amplitude if the drive voltage is the same.

  Therefore, when driving the piezoelectric elements 430a and 430b so as to excite the carrier vibration in the optical low-pass filter 410, the driving is higher than the driving voltage of the standing wave vibration so as to be approximately equal to the amplitude of the standing wave vibration. Apply voltage. Therefore, the power consumption of the carrier vibration is larger than the standing wave vibration.

  Therefore, the optical low-pass filter 410 is vibrated and the optical low-pass filter 510 is vibrated by standing waves. By doing so, it is possible to reduce power consumption compared to driving both the optical low-pass filters 410 and 510 by carrier vibration.

  In this case, the foreign matter removing ability of the optical low-pass filter 510 is inferior. However, as described above, the imaging element 34 is less likely to see foreign matter smaller than the imaging element 33. Is acceptable. That is, it is only necessary to determine various conditions for driving the standing wave vibration so as to obtain a necessary and sufficient foreign substance removing capability for the optical low-pass filter 510. Other configurations and operational effects are the same as those in the first embodiment.

(Third embodiment)
Next, a digital camera that is a third embodiment of the imaging apparatus of the present invention will be described with reference to FIGS. In the present embodiment, portions overlapping or corresponding to those in the first embodiment will be described with reference to the drawings and symbols.

  FIG. 14 is a flowchart for explaining the foreign substance removal operation of the optical low-pass filters 410 and 510 when the camera is turned on. The processing in FIG. 14 is executed by the MPU 101 after a program stored in a ROM (not shown) is expanded in a RAM (not shown).

  In FIG. 14, in step S1400, when the main SW 43 is turned on, the MPU 101 determines in step S1401 whether the still image shooting state is selected by operating the still image / moving image switching SW 45. If the MPU 101 determines that the still image shooting state is selected, the process proceeds to step S1402. If the MPU 101 determines that the moving image shooting state is selected, the process proceeds to step S1409.

  In step S1402, the MPU 101 generates a periodic voltage for exciting the standing wave vibration only for the optical low-pass filter 410 by the piezoelectric element driving circuit 111 and applies it to the piezoelectric elements 430a and 430b, and the process proceeds to step S1403. At this time, the piezoelectric elements 430 a and 430 b expand and contract according to the voltage applied by the piezoelectric element driving circuit 111, and cause the optical low-pass filter 410 to generate standing wave vibration.

  In step S1403, when the MPU 101 is switched to the moving image shooting state by the operation of the still image / moving image switch SW45, the process proceeds to step S1404. If the MPU 101 is not switched to the moving image shooting state, the process proceeds to step S1405.

  In step S1404, the MPU 101 generates a periodic voltage for exciting the standing wave vibration only for the optical low-pass filter 510 by the piezoelectric element driving circuit 111 and applies it to the piezoelectric elements 530a and 530b, and the process proceeds to step S1405. At this time, the piezoelectric elements 530a and 530b expand and contract according to the voltage applied by the piezoelectric element driving circuit 111, and cause the optical low-pass filter 510 to generate standing wave vibration.

  On the other hand, in step S1409, the MPU 101 generates a periodic voltage for exciting the standing wave vibrations of the optical low-pass filters 410 and 510 by the piezoelectric element driving circuit 111. Then, the MPU 101 applies the voltage generated by the piezoelectric element driving circuit 111 to the piezoelectric elements 430a and 430b and the piezoelectric elements 530a and 530b, and the process proceeds to step S1405. Note that the processing from step S1405 to step S1408 is the same as the processing from step S905 to step S908 in the first embodiment (FIG. 9), and a description thereof will be omitted.

  In this way, when the camera is turned on and in a still image shooting state, only the piezoelectric elements 430a and 430b are driven to remove foreign matter only from the optical low-pass filter 410 on the image sensor 33 side that captures a still image. This eliminates unnecessary driving of the piezoelectric elements 530a and 530b when taking a still image, thereby reducing power consumption. On the other hand, when the camera is turned on and in a moving image shooting state, the piezoelectric elements 430a and 430b and the piezoelectric elements 530a and 530b are driven to remove foreign matter from both the optical low-pass filters 410 and 510. This is because in the moving image shooting state, there is a possibility that still image shooting is performed during moving image shooting. This is because the side optical low-pass filter 410 also needs to remove foreign matter.

  However, simply removing foreign matter from both optical low-pass filters 410 and 510 simultaneously requires a larger amount of current to flow, leading to an increase in circuit scale and power consumption. In this case, it is conceivable to remove one of the optical low-pass filters 410 and 510 first. However, if the photographer starts the photographing operation and the foreign matter removal operation is interrupted halfway during the foreign matter removal operation of one optical low-pass filter, there is a possibility that the foreign matter remains in one optical low-pass filter.

  Therefore, in this embodiment, the MPU 101 controls the foreign substance removal operation of the optical low-pass filters 410 and 510 by driving the piezoelectric elements 430a and 430b and the piezoelectric elements 530a and 530b as follows.

  FIG. 15 is a timing chart schematically showing a drive sequence of the piezoelectric elements 430a and 430b and the piezoelectric elements 530a and 530b when removing the foreign matter of both the optical low-pass filters 410 and 510 in step S1409 of FIG. . In FIG. 15, the horizontal axis represents the elapsed time, and shows the on / off timing of the foreign substance removal operation of the optical low-pass filters 410 and 510.

  As shown in FIG. 15, the optical low-pass filters 410 and 510 are alternately subjected to the foreign substance removal operation. Specifically, during the driving time ΔT21 by the piezoelectric elements 530a and 530b of the optical low-pass filter 510, the driving by the piezoelectric elements 430a and 430b of the optical low-pass filter 410 is stopped. Next, during the driving time ΔT11 by the piezoelectric elements 430a and 430b of the optical low-pass filter 410, the driving by the piezoelectric elements 530a and 530b of the optical low-pass filter 510 is stopped. This operation is repeated a plurality of times.

  Further, the total driving time ΔT1total of the optical low-pass filter 410 by the piezoelectric elements 430a and 430b is longer than the total driving time ΔT2total of the optical low-pass filter 510 by the piezoelectric elements 530a and 530b. As described above, since the image pickup device 34 for moving image pickup has a larger pixel pitch than the image pickup device 33 for still image pickup, it is difficult to see small foreign matters, and the foreign matter removal capability is on the side of the image pickup device 34. This is because the optical low-pass filter 510 is acceptable even if it is somewhat inferior.

  In addition, the driving time ΔT11, 12, 13,... By the piezoelectric elements 430a, 430b of the optical low-pass filter 410 is proportional to the total driving time ΔT1total. Further, the driving time ΔT21, 22, 23,... By the piezoelectric elements 530a, 530b of the optical low-pass filter 510 is proportional to the total driving time ΔT2total. Thereby, the degree of foreign matter removal for each elapsed time of the optical low-pass filters 410 and 510 can be made the same.

  As shown in FIG. 15, when performing the foreign matter removing operation of both the optical low-pass filters 410 and 510, the foreign matter removing operation of the optical low-pass filter 510 on the image pickup device 34 side that captures a moving image is performed first. This is because in the moving image shooting state, moving image shooting is mainly performed, and therefore the priority of foreign matter removal by the optical low-pass filter 510 is high.

  As described above, in the present embodiment, when performing the foreign matter removal operation of both the optical low-pass filters 410 and 510, the foreign matter removal operation is alternately performed. Thereby, an increase in circuit scale and an increase in power consumption can be suppressed. In addition, the degree of removal of foreign matters attached to the optical low-pass filters 410 and 510 is not biased to either one. For this reason, even when the photographer starts the shooting operation and the foreign object removal operation is interrupted in the middle, the degree of foreign object removal can be performed in a well-balanced manner, without causing the photographer to feel stress at power-on, It is possible to suppress power consumption. Other configurations and operational effects are the same as those in the first embodiment.

  The configuration of the present invention is not limited to those exemplified in the above embodiments, and the material, shape, dimensions, form, number, arrangement location, and the like are appropriately changed without departing from the gist of the present invention. Is possible.

  For example, in each of the above embodiments, two piezoelectric elements are arranged for each of the two optical low-pass filters 410 and 510, but one piezoelectric element is provided for one of the optical low-pass filters, or both optical low-pass filters. One filter may be arranged at a time.

  In each of the above embodiments, the two optical low-pass filters 410 and 510 are configured to excite vibration in the optical low-pass filter made of a quartz birefringent plate, but the birefringent plate is not made of quartz but niobic acid. Lithium may be used. Further, a configuration may be adopted in which vibration is excited in an optical low-pass filter or an infrared absorption filter alone configured by bonding a birefringent plate, a phase plate, and an infrared absorption filter. Furthermore, a configuration may be adopted in which vibration is excited in a single glass plate disposed in front of the birefringent plate.

6 Semi-transmissive mirror 33 Image sensor 34 Image sensor 43 Main SW
45 Still / Movie switching SW
100 Camera body 101 MPU
201 Photography lens 410 Optical low-pass filters 430a and 430b Piezoelectric element 510 Optical low-pass filters 530a and 530b Piezoelectric element

Claims (12)

An imaging apparatus comprising a mirror that transmits a subject light flux that has passed through a photographing optical system and guides it to the first image sensor, and reflects a part of the subject light flux to guide the second image sensor,
A first optical filter disposed on the subject side of the first image sensor;
A first vibrating element that excites vibrations in the first optical filter to remove foreign matter adhering to the first optical filter;
A second optical filter disposed on the subject side of the second image sensor;
A second vibrating element that excites vibrations in the second optical filter to remove foreign matter adhering to the second optical filter;
Control means for controlling the driving of the first vibration element and the second vibration element,
The first image sensor and the second image sensor have different pixel pitches,
The control means includes: one of the first vibration element and the second vibration element that uses power consumed by a vibration element that excites vibration in an optical filter disposed on a subject side of the imaging element having the larger pixel pitch. An image pickup apparatus that controls driving of the first vibration element and the second vibration element so as to be smaller than power consumed by the vibration element.   The imaging apparatus according to claim 1, wherein the control unit controls a voltage applied to the first vibration element and the second vibration element. The image sensor on the side with the larger pixel pitch is the second image sensor,
The ratio of the applied voltage of the second vibrating element to the area of the second optical filter is smaller than the ratio of the applied voltage of the first vibrating element to the area of the first optical filter. Imaging device.   The imaging apparatus according to claim 1, wherein the control unit controls a time for driving the first vibration element and the second vibration element.   The imaging apparatus according to claim 1, wherein the control unit controls the number of times of driving the first vibration element and the second vibration element.   The imaging apparatus according to claim 1, wherein the control unit controls a driving frequency applied to the first vibrating element and the first vibrating element.   The imaging apparatus according to claim 6, wherein the control unit gradually changes a driving frequency applied to the first vibrating element and the second vibrating element, and makes the gradually changing directions of the driving frequency different from each other. .   Each of the first optical filter and the second optical filter is a rectangular optical low-pass filter, and a point image separation direction of the first optical filter and a point image separation direction of the second optical filter are different from each other. The imaging apparatus according to claim 1, wherein the imaging apparatus is provided.   The other vibration element excites two bending vibrations having different orders by shifting the time phase with respect to the optical filter disposed on the subject side of the image pickup element having a smaller pixel pitch. The imaging device according to any one of claims 1 to 8.   The said 1st vibration element and the said 2nd vibration element excite standing wave vibration with respect to a 1st optical filter and a 2nd optical filter, respectively, The Claim 1 thru | or 8 characterized by the above-mentioned. Imaging device. An imaging apparatus comprising a mirror that transmits a subject light flux that has passed through a photographing optical system and guides it to the first image sensor, and reflects a part of the subject light flux to guide the second image sensor,
A first optical filter disposed on the subject side of the first image sensor;
A first vibrating element that excites vibrations in the first optical filter to remove foreign matter adhering to the first optical filter;
A second optical filter disposed on the subject side of the second image sensor;
A second vibrating element that excites vibrations in the second optical filter to remove foreign matter adhering to the second optical filter;
Control means for controlling the driving of the first vibration element and the second vibration element,
The first image sensor and the second image sensor have different pixel pitches,
Of the first vibrating element and the second vibrating element, the driving area of another vibrating element is greater than the driving area of a vibrating element that excites vibration in an optical filter disposed on the subject side of the imaging element having the larger pixel pitch. An imaging device characterized in that is larger. The image sensor on the side with the larger pixel pitch is the second image sensor,
12. The ratio of the driving area of the second vibrating element to the area of the second optical filter is smaller than the ratio of the driving area of the first vibrating element to the area of the first optical filter. The imaging device described in 1.

Images