JP3980804B2 - Imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an imaging apparatus, and more particularly, to an imaging apparatus applied to a digital camera or the like provided with an extendable actuator that moves an imaging element.
[0002]
[Prior art]
Recently, digital cameras have become widespread, and there are also known ones in which the image sensor portion is unitized. FIG. 8 shows a schematic configuration of a lens barrel unit of a conventional digital camera in which an image sensor portion is unitized. In the figure, reference numeral 100 denotes a lens barrel unit. In the lens barrel unit 100, an optical unit and a CCD unit are provided. The optical unit includes lenses 101 a and 101 b, a lens driving system 102, and an LPF 103. The CCD unit includes an image sensor (CCD) 104, a CCD frame 105, and a CCD press 106.
[0003]
As described above, the performance management is facilitated by separating the optical unit and the CCD unit (the optical system should be managed by the optical unit and the imaging system should be managed by the CCD unit, respectively). By inserting a washer or the like between them, there is an advantage that coarse adjustment of the focus position and the like is possible.
[0004]
Usually, since the mounting reference of the image sensor (CCD) 104 in the optical axis direction is the back surface, the position is defined by a sheet metal part (CCD holder 106), and the plastic part (vertical and horizontal directions) is positioned on the sheet metal part ( The position is determined by the CCD frame 105). In other words, the CCD unit is configured such that the image pickup device 104 is sandwiched between the CCD press 106 and the CCD frame 105 and the CCD press 106 and the CCD frame 105 are fixed. In addition, an electrical system (PCB or FPC) for driving the image sensor 104 is disposed on the rear side of the image sensor 104 with the CCD press 106 interposed therebetween.
[0005]
In addition, recently, there is also known an apparatus in which an image pickup element is driven by an expandable piezoelectric element to perform pixel shift shooting. FIG. 9 is a diagram showing a schematic configuration of a lens barrel unit of a conventional digital camera that performs photographing with shifted pixels. In the figure, reference numeral 200 denotes a lens barrel unit. In the lens barrel unit 200, lenses 201a and 201b, a lens driving system 202, an LPF 203, an image sensor (CCD) 204, and a stacked piezoelectric element 205 are provided. ing.
[0006]
The stacked piezoelectric element 205 is disposed on the side surface of the imaging element 204. The laminated piezoelectric element 205 has a property of expanding and contracting in the longitudinal direction when a voltage is applied. One end is in contact with a fixed system (a part of the lens barrel unit 200) and the other end is in contact with an image sensor (CCD) 204. ing. The multilayer piezoelectric element 205 moves the image sensor 204 by a minute amount (for example, half pixel to one pixel) in a direction orthogonal to the optical axis. By capturing and synthesizing images before and after moving the image sensor 204, it is possible to obtain a high-resolution image that exceeds the number of pixels of the image sensor.
[0007]
[Problems to be solved by the invention]
However, as shown in FIG. 9, the structure in which the laminated piezoelectric element is arranged on the side surface of the imaging element is simple in structure, so that disturbance is not easily applied to the pixel shifting operation, and there is an advantage that stable operation can be performed. There is a problem that the lens barrel unit protrudes. Such a protrusion is a major obstacle to miniaturization of the camera. Also, if one end of the laminated piezoelectric element is received by the lens barrel unit receiving member, the pixel shift unit cannot be unitized, and the pixel shift performance must be managed by the entire lens barrel unit including the optical system. This is not preferable in the assembly process. In addition, even if it is attempted to unitize the pixel shifting portion, there is a problem that it is difficult to ensure the rigidity of the member to be received because the laminated piezoelectric element is far away, and the performance becomes unstable.
[0008]
The present invention has been made in view of the above, and an object of the present invention is to provide an imaging apparatus capable of saving a lens barrel unit in an imaging apparatus that performs imaging by shifting pixels.
[0009]
[Means for Solving the Problems]
To achieve the above object, the present invention provides an optical system for forming a subject image, an imaging means for converting the formed subject image into an electrical signal, and the imaging means with respect to the optical axis direction of the optical system. A telescopic actuator that moves in the vertical direction, and the telescopic actuator is disposed on the back side of the imaging means. According to the above invention, the telescopic actuator that moves the image pickup means in the direction perpendicular to the optical axis direction of the optical system is disposed on the back side of the image pickup means.
[0010]
In the present invention, the telescopic actuator is disposed at a substantially central position with respect to a direction perpendicular to both the optical axis direction of the optical system and the telescopic direction of the telescopic actuator. According to the above invention, the telescopic actuator is disposed at a substantially central position with respect to a direction perpendicular to both the optical axis direction of the optical system and the telescopic direction of the telescopic actuator.
[0011]
In addition, the present invention includes a first elastic member that is disposed at a substantially symmetrical position across the telescopic actuator and acts in a direction in which the telescopic actuator is compressed. According to the above invention, the first elastic member is disposed at a substantially symmetrical position with the telescopic actuator interposed therebetween, and acts in a direction in which the telescopic actuator is compressed.
[0012]
Further, according to the present invention, the first elastic member is an integral structure member having two elastic portions disposed at substantially symmetrical positions with the telescopic actuator interposed therebetween. According to the said invention, the 1st elastic member is comprised by the member of the integral structure which has two elastic parts arrange | positioned in a substantially symmetrical position on both sides of an expansion-contraction type actuator.
[0013]
Further, the present invention provides a first imaging means receiving member that regulates a back position of the imaging means and positions the imaging means in the optical axis direction, and is in contact with a side surface of the imaging means with respect to the optical axis direction of the imaging means. A second imaging means receiving member for holding a right angle direction, and one end of the telescopic actuator in the expansion / contraction direction abuts on the first imaging means receiving member and the other end abuts on the second imaging means receiving member. It was decided that According to the above invention, the first imaging means receiving member regulates the back position of the imaging means and positions the imaging means in the optical axis direction, and the second imaging means receiving member is in contact with the side surface of the imaging means and the imaging means. One end of the telescopic actuator is brought into contact with the first imaging means receiving member and the other end is brought into contact with the second imaging means receiving member.
[0014]
The present invention further includes a second elastic member that couples the first imaging means receiving member and the second imaging means receiving member with the imaging means sandwiched in the optical axis direction. According to the above invention, the first imaging means receiving member and the second imaging means receiving member are coupled to each other with the imaging means sandwiched in the optical axis direction by the second elastic member.
[0015]
In the present invention, the imaging means and the second imaging means receiving member are bonded to form an integral structure. According to the above invention, the imaging means and the second imaging means receiving member are bonded to form an integral structure.
[0016]
Further, according to the present invention, the imaging unit and the first imaging unit receiving member are press-contacted via a thin plate-like friction reducing member. According to the above invention, the imaging means and the first imaging means receiving member are pressed against each other via the thin plate-like friction reducing member.
[0017]
The present invention further includes a filter member between the optical system and the imaging unit, and the filter member has an MTF characteristic including the optical system of 20 to 45% at the Nyquist frequency of the imaging unit. It has such filter characteristics. According to the above invention, the filter member is disposed between the optical system and the imaging unit, and has a filter characteristic such that the MTF characteristic including the optical system is 25 to 40% at the Nyquist frequency of the imaging unit.
[0018]
In the present invention, the telescopic actuator is a multilayer piezoelectric element. According to the above invention, the telescopic actuator is constituted by the laminated piezoelectric element.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Exemplary embodiments of a digital camera to which an imaging apparatus according to the present invention is applied will be described below in detail with reference to the accompanying drawings.
[0020]
FIG. 1 is a block diagram showing a configuration of a digital camera according to the present embodiment. The digital camera 1 shown in FIG. 1 is roughly divided into main components, and a lens barrel unit 2 that captures an object and obtains analog image data, and analog image data obtained by the lens barrel unit 2 are digitized. And a signal processing unit 3 that processes the digital image data and outputs it to the outside.
[0021]
In this digital camera 1, an A / D conversion unit 4 for analog-digital conversion of image data is provided between the lens barrel unit 2 and the signal processing unit 3, and a mode switch (not shown) or the like is provided in the signal processing unit 3. A signal generator 5 is connected to the signal processing unit 3 for generating a signal in response to the operation and outputting the signal to the signal processing unit 3.
[0022]
The lens barrel unit 2 includes an optical unit 10 and a pixel shifting unit 20. The optical unit 10 includes a lens 11 for forming an image of a subject, a shutter mechanism (mechanical shutter, diaphragm, etc.) 12 that shields light incident on the lens 11 with an optical mechanism, an LPF (low-pass filter) 13, and a signal. A lens driving system 14 that moves the lens 11 and drives the shutter mechanism 12 under the control of the processing unit 3 is provided.
[0023]
By the way, it is preferable not to use the LPF during pixel-shifted shooting. Therefore, it is ideal to provide a mechanism for taking the LPF into and out of the optical path. FIG. 2 is a diagram illustrating characteristics of an LPF that is normally used (a digital camera that does not have a pixel shifting function). In the figure, the horizontal axis represents the spatial frequency and the vertical axis represents the MTF. In a digital camera that does not have a pixel shifting function, the LPF is usually designed so that the MTF at the Nyquist frequency (frequency determined by the pixel pitch) is 0%, as shown in FIG.
[0024]
If there is enough space in the digital camera, an LPF retracting space can be secured. However, in a small camera such as this embodiment, the LPF retracting space and the drive mechanism space cannot be secured easily. On the other hand, if the LPF is not used, a pseudo color is generated during normal shooting, and the image quality is deteriorated.
[0025]
Therefore, in this embodiment, an LPF having characteristics as shown in FIG. 3 is used in order to ensure a certain level of quality in both normal shooting and pixel-shifted shooting without allocating extra space. In the figure, the horizontal axis represents the spatial frequency and the vertical axis represents the MTF. As shown in the figure, an LPF having an intermediate characteristic between a normal LPF use state and a state without LPF (the MTF at the Nyquist frequency is about 30% or between 25 and 45%) is used. Thus, normal shooting and pixel-shifted shooting can be realized with one LPF, and the camera can be easily downsized. Strictly speaking, since both photographings are not in an ideal state, some image quality deterioration and pseudo color are generated, but this is an acceptable level and is negligible for the resulting merit (miniaturization).
[0026]
The pixel shifting unit 20 is disposed on the back side of the imaging device 21 including an imaging device unit including an imaging device (see FIG. 4) 21 that receives light incident on the lens 11 and converts it into an electrical signal (analog image data). Under the control of the signal processing unit 3, the light receiving surface of the image sensor 21 is moved in parallel (perpendicular to the optical axis) between the imaging surface 21 and the imaging range of the same subject is changed to perform pixel shifting. And a laminated piezoelectric element 26. The output of the image sensor 21 is supplied to the A / D converter 4.
[0027]
The signal processing unit 3 includes, for example, a system controller 30, a sensor data output unit 31, a memory group 32 including a plurality of memories, a pixel shift processing unit 33, and the like.
[0028]
The system controller 30 includes a lens driving system 14 of the optical unit 10, an imaging device 21 and a laminated piezoelectric element 26 of the pixel shifting unit 20, an A / D conversion unit 4, a sensor data output unit 31, a memory group 32, and a pixel shifting processing unit. 33 and the signal generator 5 and the like, and controls image pickup operation, A / D conversion, memory read / write, pixel shift, operation according to key input, and the like. The system controller 30 is constituted by a microcomputer or the like, and executes control of each unit and arithmetic processing by operating the microcomputer according to various programs stored in advance in the ROM.
[0029]
The sensor data output unit 31 is coupled to the output of the A / D conversion unit 4 and inputs digital image data. The sensor data output unit 31 inputs the input digital image data to any one of the memory groups 32 in the subsequent stage according to the control of the system controller 30. Output.
[0030]
The memory group 32 has a plurality of memories. According to the control of the system controller 30, one memory is used for storing image data for each imaging operation, or digital image data is read from one memory and the subsequent pixels are read out. This is supplied to the shift processing unit 33.
[0031]
The pixel shift processing unit 33 performs pixel shift processing based on the digital image data supplied from the memory group 32. Specifically, the pixel shift amount when the imaging range is changed by the stacked piezoelectric element 26 The image quality of the same subject is increased in accordance with (for example, pixel 1/2 pitch), and finally image data for one sheet is obtained.
[0032]
The output of the pixel shift processing unit 33 is connected to an external terminal (not shown) and can be sent out by connecting to an external device such as a personal computer. The signal generator 5 includes a release key for operating the electronic shutter and the shutter mechanism 12 to perform imaging, a mode switch for setting various modes, and the like.
[0033]
The structure of the pixel shifting unit 20 shown in FIG. 1 will be described with reference to FIGS. 4 is an exploded perspective view of the pixel shifting unit 20 of FIG. 1, FIG. 5 is a rear view of the pixel shifting unit 20 of FIG. 1, FIG. 6 is a central sectional view of the pixel shifting unit 20 of FIG. A side view of the pixel shifting unit 20 is shown.
[0034]
In FIG. 4, reference numeral 21 denotes an image sensor (CCD) that converts the formed subject image into image data. Reference numeral 22 denotes a CCD frame that contacts the side surface of the image sensor 21 and positions in the vertical direction (perpendicular to the optical axis). (Second imaging means receiving member), 23 is a lens barrel frame, 24 is a CCD press (first imaging means receiving member) that contacts the back surface of the imaging element 21 and positions the imaging element 21 in the optical axis direction, 25 A flexible printed board 26 is disposed on the back surface of the image sensor 21 and moves the image sensor 21 in a direction perpendicular to the optical axis direction, and 27 includes a torsion spring. The CCD frame 22 sandwiches the image sensor 21. A pair of spring members (second elastic members) 28 and 28, which join the CCD presser 24, have an integral shape in which two tension springs are connected in a U-shape, and the laminated piezoelectric element 26 is attached in the expansion / contraction direction. Force Ne showing components (first elastic member).
[0035]
As shown in FIG. 4, the lens barrel frame 23 is provided with screw holes 23a, 23b, and 23c. The CCD frame 22 is in contact with the side surface of the image sensor 21 and performs positioning in the vertical direction (perpendicular to the optical axis), and is made of a plastic material. A window 22a for allowing light to enter the light receiving surface of the image sensor 21 is provided on the front surface of the CCD frame 22, and a pair of substantially L-shaped projections 22b and 22c are provided on both side surfaces, respectively. Is provided with a protruding member 22e having a flat bottom surface. The protruding member 22e is provided with a pair of spring hooks 22e1 on both side surfaces thereof.
[0036]
The CCD retainer 24 is made of a sheet metal part, and is provided with screw holes 24a, 24b, and 24c for screwing to the lens barrel frame 23, and a screw hole 24f for screwing to the flexible printed board 25. Is provided. Further, the CCD retainer 24 is provided with a pair of spring hooks 24e for hooking a pair of spring members 27 on its side surfaces, and a bent portion 24d bent at a substantially right angle.
[0037]
The flexible printed board 25 is provided with a horizontally long hole 25ba for inserting the bent portion 24d of the CCD press 24 and a screw hole 25b for screwing with the CCD press 24.
[0038]
And as shown in FIG. 6, the image pick-up element 21 is comprised from the image pick-up part 21a, CCD base material 21b, and CCD glass 21c. The imaging element 21 is formed so as to form an integral structure by being bonded to the CCD frame 22 with an adhesive. As shown in FIGS. 4, 6, and 7, the CCD frame 22 and the CCD retainer 24 are urged by a pair of spring members 27 with the imaging device 21 and the thin plate-like friction reducing member 34 interposed therebetween. Specifically, the spring portions of the pair of spring members 27 are respectively hooked on the pair of spring hook portions 24e of the CCD retainer 24, and both ends of the spring member 27 urge the protrusions 22b and 22c of the CCD frame 22 in the direction of the arrow. ing. The CCD holder 24 is screwed to the lens barrel frame 23 with screws 29a, 29b, and 29c. The CCD frame 22 is configured to be movable in a small amount in the vertical direction with respect to the lens barrel frame 23, and the friction reducing member 34 described above reduces the influence of the frictional burden due to the surface roughness of the back surface of the image sensor during movement. Is sandwiched between.
[0039]
As shown in FIGS. 5 to 7, the bent portion 24d of the CCD retainer 24 is inserted into the horizontally long hole 25a of the flexible printed board 25, and the laminated piezoelectric element 26 is placed in the bent portion 24d. The image sensor 21 is disposed at a substantially central position in the lateral direction (the direction perpendicular to the optical axis direction and the expansion / contraction direction of the multilayer piezoelectric element). The spring member 28 is sandwiched from the lower side of the bent portion 24d of the CCD holder 24 so that the protruding member 22e of the CCD frame 22 and the upper surface of the multilayer piezoelectric element 26 are in contact with each other, and both sides of the protruding member 22e of the CCD frame 22 are placed. The projections 22e of the CCD frame 22 are urged downward and the bent portions 24d of the CCD retainer 24 are urged upward.
[0040]
Thereby, the laminated piezoelectric element 26 is urged in the expansion / contraction direction. At this time, the pair of spring portions 28 a of the spring member 28 are disposed at substantially symmetrical positions with respect to the laminated piezoelectric element 26. Further, the flexible printed board 25 is screwed to the CCD holder 24 with screws 29d.
[0041]
In the pixel shifting unit 20 having the above-described structure, when the multilayer piezoelectric element 26 expands under the control of the signal processing unit 3, the protruding member 22e of the CCD frame 22 is pushed by the multilayer piezoelectric element 26, and the CCD frame 22 is moved upward. Move in the direction. As a result, the image sensor 21 moves upward.
[0042]
As described above, according to the pixel shifting unit 20, since the multilayer piezoelectric element 26 is arranged on the back side of the imaging element 21, the lens barrel unit can be saved in space. In addition, the protrusion on the lower side of the lens barrel unit can be eliminated as compared with the structure in which the multilayer piezoelectric element is arranged on the side surface with respect to the imaging element as in the prior art shown in FIG. It becomes possible.
[0043]
Further, according to the pixel shifting unit 20, the laminated piezoelectric element 26 is arranged at a substantially central position in the lateral direction of the imaging element 21, so that when the laminated piezoelectric element 26 expands and contracts, the left and right loads It is possible to prevent the balance from being lost, and it is possible to move the imaging element straight without tilting.
[0044]
Further, according to the pixel shifting unit 20, the spring member 28 is disposed at a substantially symmetrical position with the multilayer piezoelectric element 26 interposed therebetween, and the multilayer piezoelectric element 26 is biased in the expansion / contraction direction. The element 26 can be prevented from being tilted by disturbance.
[0045]
Further, according to the pixel shifting unit 20, the spring member 28 is not provided in the bent portion 24 d of the CCD holding member 24, and the spring member 28 is integrated with the two tension springs in a U-shape. Since the spring is applied to the portion (the bent portion 24d of the CCD retainer 24) that receives the multilayer piezoelectric element 26, the hole of the flexible printed board 25 can be made as small as possible. In other words, the wiring for operating the image sensor 21 is made by the flexible printed board 25, and the flexible printed board 25 is inserted through the bent portion 24 d of the CCD press 24 that receives the laminated piezoelectric element 26. A hole 25a is provided. The hole 25a is preferably kept as small as possible for wiring and mounting of the flexible printer board 25. Temporarily, if projections for spring hooking are provided on both sides of the portion that receives the multilayer piezoelectric element (the bent portion 24d of the CCD retainer 24), it is necessary to enlarge the hole 25a of the flexible printed board 25, and the wiring is increased accordingly. It becomes very strict.
[0046]
Further, according to the pixel shifting unit 20, the CCD retainer 24 regulates the position of the back surface of the image sensor 21 to position the image sensor 21 in the optical axis direction, and the CCD frame 22 is in contact with the side surface of the image sensor 21. Since one end of the multilayer piezoelectric element 26 in the expansion / contraction direction is in contact with one end of the CCD retainer 24 and the other end is in contact with the CCD frame 22, the components related to the pixel shifting mechanism are In addition to being minimal, all the pixel shifting mechanisms can be provided in the pixel shifting unit, facilitating performance management.
[0047]
Further, according to the pixel shifting unit 20, the CCD frame 21 and the CCD retainer 24 are joined by the spring member 27 with the image sensor 21 sandwiched in the optical axis direction. Can be prevented, and it is possible to prevent the image from being out of focus and the occurrence of one-sided blurring of the image.
[0048]
Further, since the thin plate-like friction reducing member 34 for reducing friction is sandwiched between the image pickup device and the CCD presser, it is possible to prevent the surface roughness of the back surface of the image pickup device from adversely affecting the frictional load. And a stable amount of movement can be secured.
[0049]
Further, according to the pixel shifting unit 20, since the image pickup device 21 and the CCD frame 22 are bonded to form an integrated structure, the moving amount of the image pickup device 21 can be stabilized, and an image by pixel shifting can be obtained. Can be realized stably. In addition, as a movement when a voltage is applied to the multilayer piezoelectric element, the CCD frame moves up and down with respect to the fixed system CCD presser. In the prior art shown in FIG. 9, since the CCD is directly pressed, the amount of expansion and contraction of the stacked piezoelectric element = the amount of movement of the CCD. There is concern about the loss of travel due to In order to solve such a problem, the image sensor 21 and the CCD frame 22 are bonded and integrated as described above.
[0050]
As another method, there is a method in which the image pickup element 21 and the CCD frame 22 are press-fitted. However, since the external dimension tolerance of the CCD is very rough, the CCD frame is made of a material having sufficient elastic force for press-fitting. It is necessary to consist of. However, if a material having such an elastic force is used, the receiving portion (protruding member) of the stacked piezoelectric element of the CCD frame will bend and a loss will occur in the amount of movement, making it difficult to ensure performance.
[0051]
In addition, this invention is not limited only to the said embodiment, In the range which does not change the summary of invention, it can deform | transform suitably and can be implemented. For example, in the above embodiment, the configuration in which the image sensor is moved up and down has been described. However, the present invention is not limited to this, and the image sensor may be configured to move in the left-right direction or the diagonal direction.
[0052]
In the above embodiment, a laminated piezoelectric element is used as the telescopic actuator. However, the present invention is not limited to this, and other telescopic actuators may be used. In the above embodiment, a CCD is used as an image sensor. However, the present invention is not limited to this, and another image sensor may be used.
[0053]
Furthermore, although the torsion spring and the tension spring are used as the spring members 27 and 28 in the above embodiment, the present invention is not limited to this, and other elastic members can be used as long as the same function can be achieved. You may decide to do it.
[0054]
【The invention's effect】
As described above, according to the present invention, the telescopic actuator for moving the image pickup means in the direction perpendicular to the optical axis direction of the optical system is disposed on the back side of the image pickup means. In the apparatus, the lens barrel unit can be saved in space.
[0055]
In addition, according to the present invention, the telescopic actuator is disposed at a substantially central position with respect to the direction perpendicular to both the optical axis direction of the optical system and the telescopic direction of the telescopic actuator. In doing so, it is possible to prevent the left and right load balance from being lost, and it is possible to move the imaging device straight without tilting the imaging device.
[0056]
Further, according to the present invention, the first elastic member is disposed at a substantially symmetrical position with the telescopic actuator interposed therebetween, and acts in a direction in which the telescopic actuator is compressed. In addition to the effect of the image input apparatus according to 2, it is possible to prevent the telescopic actuator from being inclined due to disturbance.
[0057]
Further, according to the present invention, the first elastic member is constituted by an integral structure member having two elastic portions arranged at substantially symmetrical positions with the telescopic actuator interposed therebetween, so that the hole of the flexible printed board is formed as much as possible. It can be made smaller.
[0058]
According to the invention, the first imaging means receiving member regulates the back position of the imaging means to position the imaging means in the optical axis direction, and the second imaging means receiving member is in contact with the side surface of the imaging means. Since the direction perpendicular to the optical axis direction of the image pickup means is maintained, one end of the extension / contraction direction of the extendable actuator is brought into contact with the first image pickup means receiving member, and the other end is brought into contact with the second image pickup means receiving member. The components related to the pixel shifting mechanism can be minimized, and all the pixel shifting mechanisms can be provided in the pixel shifting unit, facilitating performance management.
[0059]
Further, according to the present invention, since the first imaging means receiving member and the second imaging means receiving member are coupled by sandwiching the imaging means in the optical axis direction by the second elastic member, It is possible to prevent the element from floating with respect to the first imaging means receiving member, and it is possible to prevent the focus from being out of focus or the occurrence of one-sided blur of the image.
[0060]
In addition, according to the present invention, since the imaging unit and the second imaging unit receiving member are bonded to form an integral structure, the amount of movement of the imaging element can be stabilized, and the image by pixel shift can be stabilized. High pixel count can be realized stably.
[0061]
In addition, according to the present invention, the imaging means and the first imaging means receiving member are pressed against each other through the thin plate-like friction reducing member, so that the surface roughness of the back surface of the imaging means has an adverse effect as a frictional load. Can be prevented, and a stable amount of movement can be secured.
[0062]
According to the present invention, the filter member is disposed between the optical system and the imaging unit, and has a filter characteristic such that the MTF characteristic including the optical system is approximately 30% at the Nyquist frequency of the imaging unit. Therefore, in addition to the effect of the image input device according to any one of claims 1 to 8, normal shooting and pixel-shifted shooting can be realized with one LPF, so the camera can be easily downsized. .
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a digital camera according to an embodiment.
FIG. 2 is a diagram illustrating characteristics of an LPF used in a digital camera that does not have a pixel shifting function.
FIG. 3 is a diagram showing the characteristics of the LPF according to the present embodiment.
4 is an exploded perspective view of the pixel shifting unit in FIG. 1. FIG.
FIG. 5 is a rear view of the pixel shifting unit of FIG. 1;
6 is a central cross-sectional view of the pixel shifting unit of FIG. 1. FIG.
7 is a side view of the pixel shifting unit of FIG. 1. FIG.
FIG. 8 is a diagram showing a schematic configuration of a lens barrel unit of a conventional digital camera in which an image sensor portion is unitized.
FIG. 9 is a diagram illustrating a schematic configuration of a lens barrel unit of a conventional digital camera that performs pixel-shifted shooting.
[Explanation of symbols]
1 Digital camera
2 Lens unit
3 Signal processing unit
4 A / D converter
5 Signal generator
10 Optical unit
11 Lens
12 Shutter mechanism
13 LPF (low pass filter)
14 Lens drive system
20 pixel shift unit
21 Image sensor (CCD)
22 CCD frame
23 Lens frame
24 CCD holder
25 Flexible printed boards
26 Stacked piezoelectric elements
27, 28 Spring member
30 System controller
31 Sensor data output section
32 memory groups
33 Pixel shift processing unit

Claims (13)

An optical system for forming a subject image;
An imaging member having an imaging element for converting the imaged subject image into an electrical signal;
An actuator for moving the imaging member in a direction perpendicular to the optical axis direction of the optical system;
A first imaging member receiving member that press-contacts the imaging member from a back side that is the opposite side of the optical axis direction with the subject across the imaging member;
A second imaging member receiving member in contact with the imaging member from a side surface perpendicular to the optical axis direction;
An urging member acting in a direction to compress the actuator,
The actuator is disposed on the back side of the imaging member,
One end of the actuator in the expansion / contraction direction is in contact with the first imaging member receiving member, and the other end is in contact with the second imaging member receiving member,
An imaging apparatus comprising: a coupling member that couples the first imaging member receiving member and the second imaging member receiving member with the imaging member sandwiched in an optical axis direction.   The imaging apparatus according to claim 1, wherein the coupling member is an elastic body. An optical system for forming a subject image;
An imaging member having an imaging element for converting the imaged subject image into an electrical signal;
An actuator for moving the imaging member in a direction perpendicular to the optical axis direction of the optical system;
A first imaging member receiving member that press-contacts the imaging member from a back side that is the opposite side of the optical axis direction with the subject across the imaging member;
A second imaging member receiving member in contact with the imaging member from a side surface perpendicular to the optical axis direction;
An urging member acting in a direction to compress the actuator,
The actuator is disposed on the back side of the imaging member,
The second imaging member receiving member is in contact with the imaging member from the front side,
One end of the actuator in the expansion and contraction direction is in contact with the first imaging member receiving member, and the other end is in contact with the second imaging member receiving member.   The imaging apparatus according to claim 1, wherein the imaging member and the second imaging member receiving member are bonded to form an integral structure.   5. The imaging apparatus according to claim 1, wherein the first imaging member receiving member is fixed to a fixed portion fixed to the imaging apparatus. An optical system for forming a subject image;
An imaging member having an imaging element for converting the imaged subject image into an electrical signal;
An actuator for moving the imaging member in a direction perpendicular to the optical axis direction of the optical system;
A first imaging member receiving member that press-contacts the imaging member from a back side that is the opposite side of the optical axis direction with the subject across the imaging member;
An urging member acting in a direction to compress the actuator,
The actuator and the biasing member are disposed on the back side of the imaging member,
The imaging apparatus, wherein the first imaging member receiving member is fixed to a fixing portion fixed to the imaging apparatus.   The imaging apparatus according to claim 5, wherein the fixing portion is a lens barrel frame.   The imaging apparatus according to claim 6 or 7, wherein the actuator is arranged at a substantially central position with respect to a direction perpendicular to both the optical axis direction and the expansion / contraction direction of the actuator.   The said biasing member is provided with the some coil spring part arrange | positioned in a substantially symmetrical position in the direction perpendicular | vertical to the said optical axis direction on both sides of the said actuator, The any one of Claims 6-8 characterized by the above-mentioned. The imaging device described in 1.   The image pickup apparatus according to claim 9, wherein the plurality of coil spring portions are arranged in parallel to the actuator to form an integral structure.   The imaging apparatus according to claim 1, wherein the imaging member and the first imaging member receiving member are pressed against each other via a friction reducing member.   The image pickup apparatus according to claim 1, wherein the actuator is a stacked piezoelectric element.   The imaging apparatus according to any one of claims 1 to 12, wherein the actuator includes only a single actuator.

Images