JP2012105098A - Imaging element unit and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably remove dust by suppressing fixation of the positions of vibration nodes with a simple structure when the dust is removed by vibrating an optical element.SOLUTION: An imaging element unit 200 of the present invention comprises: an imaging element 102 which has an imaging surface for forming the optical image of a subject thereon and converts the optical image into an electric signal; a piezoelectric element 114 which vibrates with input of a driving signal of one frequency; and an optical element 104 which is disposed nearer to the subject than the imaging element 102, has the piezoelectric element 114 mounted thereon, and is provided with a notch-shaped portion 104a at a section where the piezoelectric element 114 is mounted.

Description

  The present invention relates to an imaging element unit and an imaging apparatus.

  In recent years, the pixel pitch has become finer as the number of pixels of the image sensor increases. For this reason, the shadow of the dust adhering to the optical element surface in the vicinity of the image pickup surface of the image pickup element is reflected in the picked-up image, and there is a problem that affects the image quality.

  In order to cope with such a problem, for example, in Patent Document 1 below, resonance is effective for dust removal on an optical element unit in which a vibration source is incorporated for one drive frequency input to the vibration source (piezoelectric element). Since only one mode is generated, two or more different drive frequencies are sequentially input to the vibration source in order to compensate for the vibration node on the resonance mode, and two or more different resonance modes effective for dust removal are obtained. It is generated sequentially.

  In the technique described in Patent Document 2, two different drive frequencies are simultaneously input to two vibration sources, and two different resonance modes effective for dust removal are generated simultaneously.

US Patent Application Publication No. 2004-169761 JP 2010-119049 A

  However, as described in Patent Document 1, when two or more different driving frequencies are sequentially input to the vibration source, the position of the vibration node changes according to the frequency, but the vibration node has each frequency. It must exist every time. And since the amplitude becomes 0 at the position of the vibration node, even if the frequency is changed, there is a problem that the performance of removing dust at the position of the vibration node of each frequency is deteriorated. In the method described in Patent Document 1, since it is necessary to input two or more different drive frequencies to the vibration source, there is a problem that the drive circuit becomes complicated and the cost increases.

  Further, in the method described in Patent Document 2, since it is necessary to separately provide two vibration sources that are driven at different frequencies, the configuration becomes complicated, and the number of parts increases and the manufacturing process increases. There is a problem that costs increase. Further, by providing two vibration sources, it is necessary to secure a relatively large space in the apparatus, which causes a problem in that the apparatus can be downsized.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to fix the position of the vibration node with a simple configuration when the dust is removed by vibrating the optical element. It is an object of the present invention to provide a new and improved image pickup device unit and image pickup apparatus that can suppress the occurrence of dust and can reliably remove dust.

  In order to solve the above-described problems, according to an aspect of the present invention, an imaging device that has an imaging surface on which an optical image of a subject is formed, converts the optical image into an electrical signal, and driving at one frequency. A piezoelectric element that vibrates upon input of a signal, an optical element that is disposed closer to the subject than the imaging element, is mounted with the piezoelectric element, and is provided with a notch-shaped portion at a position where the piezoelectric element is mounted; An image sensor unit is provided.

  According to the above configuration, the optical element is provided with the notch-shaped part at the site where the piezoelectric element is mounted, so that the vibration can be divided by the notch-shaped part, and different modes are provided on both sides of the notch-shaped part. Vibration can be generated. Accordingly, vibrations of different modes can be propagated to the surface of the optical element, respectively, and vibration nodes can be minimized. Therefore, it is possible to reliably suppress the reduction in the dust removal capability due to the vibration node.

  Further, the optical element has an asymmetric planar shape with respect to a position where the notch-shaped portion is provided. According to such a configuration, it is possible to emphasize the propagation of vibrations in different modes on both sides of the notch shape portion by an asymmetric shape.

  In addition, a vibration suppression plate is attached to the end face side facing the portion where the cutout portion of the optical element is provided. According to such a configuration, it is possible to emphasize the propagation of vibrations in different modes on both sides of the notch shape portion by the vibration suppressing plate.

  In order to solve the above problem, according to another aspect of the present invention, an imaging optical system that forms an optical image of a subject, and an imaging surface on which the optical image of the subject is formed by the imaging optical system are provided. An image sensor that converts the optical image into an electrical signal; a piezoelectric element that vibrates when a drive signal having a frequency of 1 is input; and is disposed closer to the subject than the image sensor, and the piezoelectric element is attached, There is provided an imaging device including an optical element provided with a notch-shaped portion at a site where the piezoelectric element is mounted.

  According to the above configuration, the optical element is provided with the notch-shaped part at the site where the piezoelectric element is mounted, so that the vibration can be divided by the notch-shaped part, and different modes are provided on both sides of the notch-shaped part. Vibration can be generated. Accordingly, vibrations of different modes can be propagated to the surface of the optical element, respectively, and vibration nodes can be minimized. Therefore, it is possible to reliably suppress the reduction in the dust removal capability due to the vibration node.

  Further, the optical element has an asymmetric planar shape with respect to a position where the notch-shaped portion is provided. According to such a configuration, it is possible to emphasize the propagation of vibrations in different modes on both sides of the notch shape portion by an asymmetric shape.

  Moreover, a vibration suppression plate is affixed to the end surface side facing the site | part in which the notch shape part of the said optical element was provided. According to such a configuration, it is possible to emphasize the propagation of vibrations in different modes on both sides of the notch shape portion by the vibration suppressing plate.

  According to the present invention, when the dust is removed by vibrating the optical element, it is possible to prevent the position of the vibration node from being fixed with a simple configuration, and it is possible to reliably remove the dust. Become.

1 is a schematic diagram illustrating a configuration of an imaging apparatus according to a first embodiment of the present invention. It is a schematic diagram which shows the structure of the vibration member to which the piezoelectric element as a vibration source was attached. It is a schematic diagram which shows the resonance mode of a piezoelectric element. It is a perspective view showing the composition of the image sensor unit concerning a 1st embodiment. It is a schematic diagram which shows a mode that the vibration from the area | region B and the area | region C of a piezoelectric element propagates to a vibration member. It is a characteristic view showing the relationship between amplitude (displacement) and frequency at a specific amplitude acquisition point P. It is a perspective view which shows the structure of the image pick-up element unit which concerns on 2nd Embodiment. It is a schematic diagram which shows the example which affixed the vibration suppression board on the lower part of the vibration member.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

[1. First Embodiment]
First, a schematic configuration of the imaging apparatus 100 according to the first embodiment of the present invention will be described with reference to FIG. As illustrated in FIG. 1, the imaging apparatus 100 includes an imaging element 102, a vibrating member 104, a shutter unit 106, an imaging optical system 108, a piezoelectric element drive control circuit 110, a camera control unit 112, and a piezoelectric element 114. The image sensor 102 is composed of an element such as a CCD sensor or a CMOS sensor. The imaging apparatus 100 forms a subject image on the imaging surface of the imaging element 102 by the imaging optical system 108, and converts the subject image into an electrical signal by photoelectric conversion by the imaging element 102.

  The imaging apparatus 100 illustrated in FIG. 1 sends an input signal having a frequency of 1 to the piezoelectric element 114 that is the vibration source of the vibrating member 104 via the piezoelectric element drive control circuit 110. Then, the vibration member 104 disposed in front of the imaging element 102 is vibrated to realize an operation of removing dust attached to the vibration member 104.

  The imaging element 102 and the vibration member 104 are configured as an integrated imaging element unit 200, and a space between the imaging surface of the imaging element 102 and the vibration member 104 is sealed. Thereby, dust can be prevented from adhering to the image pickup surface of the image pickup element 102 and dust attached to the vibration member 104 can be removed, so that formation of an image due to dust on the image pickup surface can be reliably prevented.

  FIG. 2 is a schematic diagram illustrating a configuration of the vibration member 104 to which the piezoelectric element 114 as a vibration source is attached. As shown in FIG. 2, a piezoelectric element 114 is attached to the upper part of the vibration member 104. An FPC 116 for inputting a drive signal sent from the piezoelectric element drive control circuit 110 is attached to the piezoelectric element 114. The vibrating member 104 is an optical element through which light incident from the imaging optical system 108 passes, and here, a low-pass filter (LPF) is exemplified. In the present embodiment, a low-pass filter is illustrated as an optical element that is vibrated by the piezoelectric element 114, but the optical element may be a lens or a glass plate.

  In the present embodiment, the vibration member 104 as shown in FIG. 2 is vibrated with a dust removing effect. For this reason, the piezoelectric element 114 as a vibration source is vibrated, but the vibration displacement of the piezoelectric element 114 is very small. For this reason, by generating a resonance mode as shown in FIG. 3, the vibration member 104 is vibrated with a dust removing effect. Here, FIG. 3A shows a case where vibration is generated in a vibration mode in which the piezoelectric element 114 has two nodes and one antinode. FIG. 3B shows a case where vibration occurs in a vibration mode in which the piezoelectric element 114 has three nodes and two antinodes. FIG. 3B corresponds to the case where the frequency of the signal input to the piezoelectric element 114 is higher than that in FIG.

  As shown in FIG. 3, in the resonance mode, a belly portion and a node portion are generated in the vibration. Since the amplitude is large at the antinode portion of the vibration, the attached dust can be efficiently removed. On the other hand, since the amplitude of the vibration node is 0, the attached dust may not be removed.

  For this reason, in the present embodiment, when the piezoelectric element 114 is driven at a frequency of 1, the vibration is divided into two on the vibration member 104, thereby substantially generating two vibration modes, and the vibration member Nodes do not occur in the entire area 104. Accordingly, the entire region of the vibration member 104 can be constantly vibrated regardless of driving at a single frequency, and dust attached to the vibration member 104 can be reliably removed.

  FIG. 4 is a perspective view illustrating a configuration of the image sensor unit 200 according to the present embodiment. As shown in FIG. 4, the image sensor unit 200 includes a holding frame 120 and a holding plate 122. The vibration member 104 is attached to the holding frame 120 and is held in a state where it can vibrate with a cushion interposed between the holding frame 120 and the holding plate 122. A drive signal having a frequency of 1 sent from the piezoelectric element drive control circuit 110 is input from the FPC 116 to the piezoelectric element 114.

  As shown in FIG. 4, a piezoelectric element 114 is attached to the upper end surface of the vibration member 104. The piezoelectric element 114 is attached to almost the entire upper end surface along the upper end surface of the vibration member 104. The piezoelectric element 114 is bonded to the vibration member 104 by, for example, an ultraviolet curable adhesive. An FPC 116 is connected to the piezoelectric element 114.

  An input shielding notch (notch-shaped portion) 104a is provided on an end surface of the vibration member 104 to which the piezoelectric element 114 is bonded. As an example, the input shielding notch 104a is provided near the center of the end face to which the piezoelectric element 114 is bonded.

  By providing the input shielding notch 104a, the vibration of the piezoelectric element 104 is not directly transmitted to the region A of the end face of the vibrating member 104 where the input shielding notch 104a is provided. Compared with the other regions B and C, the vibration is suppressed. Accordingly, the vibration of the vibration member 104 can be divided by the input shielding notch 104a, and two different vibration states can be generated on both sides with the region A where the input shielding notch 104a is provided as a boundary. .

  The region A in which the input shielding notch 104a is provided is a so-called dead zone region in which vibration is suppressed. On the other hand, in the regions B and C on both sides of the region A, the vibration member 104 vibrates due to vibration supplied from the piezoelectric element 114.

  For this reason, in the vibration member 104, the region B and the region C divided by the region A individually vibrate, and the vibrations of both the region B and the region C propagate to the vibration member 104, whereby the piezoelectric element 114 and the vibration member Both 104 vibrate. FIG. 5 is a schematic diagram illustrating how vibration from the region B and the region C propagates to the vibration member 104.

  As shown in the middle diagram of FIG. 5, the vibration is suppressed in the region A in which the input shielding notch 104 a is provided, and vibrations having different vibration modes are transmitted from the region B and the region C, respectively. Here, the vibration mode in region B is referred to as vibration mode B, and the vibration mode in region C is referred to as vibration mode C. For this reason, although the actual input frequency to the piezoelectric element 114 is one, the effect that two different frequencies were input to the piezoelectric element 114 and vibrated can be obtained.

  For this reason, at each position on the surface of the vibration member 104, the vibration by the vibration mode B and the vibration by the vibration mode C are combined to cause displacement. At any point on the surface of the vibration member 104, even if the amplitude corresponding to the position of the node is reduced in one vibration mode, the position of the node can be prevented from being reached in the other vibration mode. Therefore, by propagating the vibrations in vibration mode B and vibration mode C together, the decrease in amplitude at the node position can be interpolated with vibrations in other vibration modes, so that the node portion can be greatly reduced. it can. As a result, it is possible to prevent the positions of the nodes where the displacement is zero from occurring in the entire region of the vibration member 104. At this time, in each vibration mode, the position of the node on the vibration member 104 changes according to the frequency of the input signal. Therefore, by setting the frequency to an optimum value, the amplitude (displacement) on the surface of the vibration member 114 is increased. It is possible to prevent the occurrence of local degradation.

  In the lowermost diagram of FIG. 5, a plurality of points shown on the surface of the vibration member 104 are amplitudes for acquiring vibration amplitude (displacement) in each of the modes B and C when simulation is performed using frequency response analysis. Indicates acquisition points. Here, as an example, 7 × 7 = 49 amplitude acquisition points on the vibration member 104 are set in a matrix. Further, the actual amplitude may be measured at the amplitude acquisition point.

  In order to prevent an amplitude node from occurring in the entire region of the vibration member 104, the frequency of the drive signal applied from the FPC 116 to the piezoelectric element 104 is set to an optimum value. For this reason, by changing the frequency input from the FPC 116 to the piezoelectric element 114, for each of the vibration mode B and the vibration mode C, a frequency at which an amplitude greater than or equal to a predetermined value is obtained at each amplitude acquisition point is acquired in advance.

  FIG. 6 is a characteristic diagram showing the relationship between the amplitude (displacement) and the frequency at a specific amplitude acquisition point P as an example. FIG. 6 shows the result of simulation using frequency response analysis. Here, FIG. 6A shows the characteristics according to the vibration mode B, and FIG. 6B shows the characteristics according to the vibration mode C. In the characteristics shown in FIGS. 6A and 6B, the vertical axis represents amplitude and the horizontal axis represents frequency.

  As shown in FIGS. 6A and 6B, when the frequency is changed, the amplitude changes as the frequency changes. As the frequency changes, the amplitude becomes the smallest when the position of the amplitude acquisition point P approaches the position of the vibration node.

  As shown in FIG. 6A, in the vibration mode B, the amplitude is close to the maximum value at the frequency f1. In the case of the same frequency f1, the amplitude is larger than the predetermined threshold value T even in the vibration mode C. Accordingly, at the amplitude acquisition point P, vibrations having a relatively large amplitude can be generated in both the vibration mode B and the vibration mode C.

  On the other hand, when the frequency is f2, the amplitude becomes smaller than the predetermined threshold value T in both the vibration mode B and the vibration mode C. Therefore, in the case of the frequency f2, vibration with sufficient amplitude cannot be generated at the amplitude acquisition point P. For this reason, it is understood from the simulation result at the amplitude acquisition point P that the frequency is preferably f1.

  The simulation as described above is performed for each amplitude acquisition point. At all amplitude acquisition points, the amplitude in the vibration modes B and C is equal to or greater than a predetermined value, and the frequency f2 in FIGS. 6 (A) and 6 (B) is obtained. The frequency f0 that does not become such a state is extracted. Accordingly, when the piezoelectric element 114 is driven at the frequency f0, sufficient amplitude is obtained at each amplitude acquisition point, so that dust attached to the entire surface of the vibration member 104 can be reliably removed. The number of amplitude acquisition points described above is an example, and the number of amplitude acquisition points can be set as appropriate.

  Further, when the horizontal position and width of the input shielding notch 104a (the length of the region A in the longitudinal direction of the piezoelectric element 114) are changed, the broken line shown in FIG. 6 (A) and FIG. 6 (B), or As shown by the characteristics of the one-dot chain line, the characteristics of displacement with respect to the frequency can be changed. Therefore, in the above-described simulation, by changing the frequency and performing the simulation by changing the horizontal position of the input shielding notch 104a or the width of the input shielding notch 104a as necessary, It is possible to extract a frequency f0 at which sufficient amplitude can be obtained at all amplitude acquisition points.

  When the position of the input shielding notch 104a is brought close to the end of the piezoelectric element 114, the amplitude of one vibration of the vibration modes B and C may be reduced. On the other hand, if the input shielding notch 104a is disposed near the center in the longitudinal direction of the piezoelectric element 114, both the amplitudes of the vibration mode B and the vibration mode C can be increased. However, since the amplitude at each amplitude acquisition point varies according to the input frequency, the optimum position and width of the input shielding notch 104a are set by the method described in FIG.

  As described above, in both vibration mode B and vibration mode C, the frequency is set so that the amplitude of each amplitude acquisition point is not less than a predetermined value, and the position and length of region A are adjusted as necessary. Thus, it is possible to reliably generate vibration with sufficient displacement in the entire region of the vibration member 104, and it is possible to reliably remove dust attached to the surface of the vibration member 104.

  Therefore, the vibration node on the vibration member 104 can be greatly reduced without changing the drive frequency of the piezoelectric element 114, and as a result, the proportion of the effective dust removal time in the drive time can be increased. it can. Accordingly, the performance of removing dust adhering to the vibrating member 104 can be remarkably improved, and a circuit configuration for changing the frequency is not necessary, so that the configuration can be simplified. Cost reduction can be realized. Further, since only one piezoelectric element 104 as a vibration source is required, the manufacturing cost can be greatly reduced as compared with a configuration in which two vibration sources (piezoelectric elements) and a drive circuit are provided. It is possible to achieve downsizing.

  As described above, according to the first embodiment, since the input shielding notch 104a is provided in a part of the vibration member 104 so as to divide the vibration of the vibration member 104, a plurality of vibrations are generated from one input frequency. A mode can be created. Then, by setting the frequency so that the amplitude of each amplitude acquisition point set on the vibration member 104 is equal to or higher than a predetermined value necessary for dust removal, dust can be reliably removed in the entire region of the vibration member 104. Become.

[2. Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 7 is a perspective view illustrating a configuration of an image sensor unit 200 according to the second embodiment. In the second embodiment, an asymmetrical shape portion 104b is added to the vibration member 104 of the first embodiment.

  As shown in FIG. 7, a part of the lower end of the vibration member 104 is provided with an asymmetric shape portion 104 b that protrudes downward. As described in the first embodiment, the vibration of the vibration member 104 can be separated by providing the vibration member 104 with the input shielding notch 104a, and a plurality of vibration modes are generated from one input frequency. be able to. Furthermore, by providing the vibration member 104 with the asymmetrical shape portion 104b, it is possible to emphasize the asymmetric propagation of vibration with the input shielding notch 104a as a boundary. For this reason, the asymmetric shape portion 104b can be provided so that the vibration member 104 has an asymmetric shape in the direction in which the piezoelectric element 114 extends, with the position where the input shielding notch portion 104a is provided as a boundary. Thereby, the difference in mode between vibration mode B and vibration mode C can be emphasized more.

  Thereby, at any point of the vibration member 104, the asymmetrical shape portion 104b is formed together with the input shielding notch portion 104a, so that vibrations due to different vibration modes B and C occur, so that the position of the node occurs in the vibration. This can be suppressed more reliably.

  FIG. 8 shows an example in which a vibration suppression plate 118 is attached to the lower part of the vibration member 104 instead of providing the asymmetric shape portion 104b. The vibration suppression plate 118 is made of a material having material characteristics (density and Young's modulus) that are less likely to vibrate than the vibration member 104. As an example, the vibration suppression plate 118 is made of a material having high rigidity such as stainless steel and has a Young's modulus sufficiently higher than that of the vibration member 104. For this reason, in the region where the vibration suppression plate 118 of the vibration member 104 is bonded, the vibration is suppressed compared to other regions of the vibration member 104, and the difference between the vibration mode B and the vibration mode C is more emphasized. can do.

  As described above, according to the second embodiment, in addition to the configuration of the vibration member 104 of the first embodiment, the vibration member 104 is provided with the asymmetric shape portion 104a, or the vibration member 104 is provided with the vibration suppression plate 118. Since it is affixed, the asymmetric propagation of vibration caused by the input shielding notch 104a can be more emphasized. Accordingly, a plurality of different vibration modes can be generated in the piezoelectric element 114 using one input frequency, and dust can be reliably removed over the entire area of the vibration member 104.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Imaging device 102 Imaging element 104 Vibrating member 104a Input shielding notch 114 Piezoelectric element 200 Imaging element unit

Claims (6)

An imaging device having an imaging surface on which an optical image of a subject is formed, and converting the optical image into an electrical signal;
A piezoelectric element that vibrates when a drive signal having a frequency of 1 is input;
An optical element that is disposed closer to the subject than the imaging element, is mounted with the piezoelectric element, and is provided with a notch-shaped portion at a position where the piezoelectric element is mounted;
An image pickup device unit comprising:   2. The image sensor unit according to claim 1, wherein the optical element has an asymmetric planar shape with respect to a position where the notch-shaped part is provided.   The imaging element unit according to claim 1, wherein a vibration suppression plate is attached to an end surface facing the portion where the cutout portion of the optical element is provided. An imaging optical system that forms an optical image of the subject;
An imaging device having an imaging surface on which an optical image of a subject is formed by the imaging optical system, and converting the optical image into an electrical signal;
A piezoelectric element that vibrates when a drive signal having a frequency of 1 is input;
An optical element that is disposed closer to the subject than the imaging element, is mounted with the piezoelectric element, and is provided with a notch-shaped portion at a position where the piezoelectric element is mounted;
An imaging apparatus comprising:   The imaging apparatus according to claim 4, wherein the optical element has an asymmetric planar shape with respect to a position where the cutout shape portion is provided.   The image pickup apparatus according to claim 4, wherein a vibration suppression plate is attached to an end surface facing the portion where the cutout portion of the optical element is provided.

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