JP5223960B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus, and more particularly to an imaging apparatus provided with a drive element that drives a lens barrel that holds an imaging optical system.

  In a conventional imaging apparatus such as a digital camera or a video camera, an autofocus function is realized by moving all or a part of a photographing lens with a motor. However, with such a method, the desired focusing performance cannot be obtained due to the backlash of the gear system that transmits the power of the motor, and in particular, in a video camera, the motor driving sound is recorded together with the sound. was there.

  Therefore, as a method of reducing the opportunity for recording the motor drive sound and improving the focusing performance, the focusing motor is roughly focused, the polymer actuator is used for precise focusing, and the polymer actuator is used for the photographing lens. A method of detecting the in-focus state and the moving direction of the lens by slightly vibrating the lens has been proposed (see, for example, Patent Document 1).

JP 2007-94237 A

  However, in the method of Patent Document 1, since the driving shaft and the guide shaft of the focusing motor are provided outside the lens holding frame, the outer shape of the lens driving device is increased, and the recent camera-equipped mobile phone It cannot be applied to a micro imaging device such as a telephone. Although the probability of using the focus motor is low, when the focus motor is used, the driving sound of the motor is recorded, and the problem has not been solved.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an imaging apparatus that is compact, high-performance, excellent in quietness, and suitable for a camera-equipped mobile phone or the like.

  The object of the present invention can be achieved by the following constitution.

An imaging apparatus according to a first aspect includes an optical unit having a lens barrel to which an imaging optical system is fixed, an imaging unit having an imaging element disposed on an optical axis of the imaging optical system, and a cylindrical shape And a driving element that expands and contracts in a direction parallel to the optical axis of the imaging optical system, and the driving element is disposed between the lens barrel and the imaging unit, and has one of the cylindrical shapes. And the other end surface of the cylindrical shape is directly bonded to the imaging unit to support the optical unit as a cylindrical structure. The drive element is divided into a plurality of partial elements by providing a plurality of partial electrodes along the circumferential direction of the cylindrical shape, and the plurality of partial elements are expanded and contracted in a direction parallel to the optical axis. the drive element is moved to said barrel and By, with the image-capturing optical system which is fixed to the lens barrel, and wherein the changing the distance between the optical unit.

The imaging device according to a second aspect is the imaging device according to the first aspect, wherein the drive element is configured such that some of the plurality of partial elements expand and contract relative to other partial elements. wherein the Rukoto is tilted to the optical axis of the imaging optical system by.

The image pickup apparatus according to a third aspect is the image pickup apparatus according to the first aspect, wherein the drive element causes the image pickup optical system to move along the optical axis when all of the plurality of partial elements expand and contract equally. characterized Rukoto move in parallel.

Fourth imaging apparatus according to the embodiment of the imaging apparatus according to to the first no third any one embodiment, the plurality of partial elements, respectively, and a variable portion that expands and contracts depending on the applied voltage, the A laminated type actuator in which a structure having an electrode part for applying a voltage between both ends of the variable part is sequentially laminated, and a part other than the plurality of partial elements of the drive element is the same as the variable part It characterized that you have been formed by material.
An imaging device according to a fifth aspect is the imaging device according to the fourth aspect, wherein the lens barrel is formed of the same material as the variable portion without having an electrode, and the lens barrel and the drive element Is characterized by being formed integrally.

According to any of the first to fifth aspects of the invention, the cylindrical driving element provided in the imaging device is disposed between the lens barrel and the imaging unit, and one end surface of the cylindrical shape is disposed on the cylindrical driving element. The optical unit is supported as a cylindrical structure by being directly joined to the image plane side end face of the lens barrel and the other end face being joined directly to the imaging unit. And the said drive element changes the space | interval of the imaging optical system fixed to the lens barrel, and an optical unit by expanding and contracting in the direction parallel to the optical axis of an imaging optical system, and moving a lens barrel. Therefore, according to any of the first to fifth aspects, the imaging optical system can be driven with the same outer shape as the lens barrel, and it is compact, high performance and excellent in quietness. An imaging device including a suitable optical unit can be provided. In addition, according to any of the first to fifth aspects, the imaging optical system can be driven with the same external shape as the optical unit, and the camera-equipped mobile phone is compact, high-performance and excellent in quietness. An imaging device suitable for the above can be provided.

According to the fifth aspect of the invention, since the drive element and the lens barrel are integrally formed, it is possible to reduce the number of parts and the manufacturing process such as the bonding process, and to provide an imaging apparatus that is excellent in cost reduction. Can do.

According to any of the first to fifth aspects of the invention, a plurality of partial elements are provided along the circumferential direction of the cylindrical shape of the drive element, and each of the plurality of partial elements is individually imaged optically. Since the optical axis of the photographing optical system can be tilted, the optical axis of the photographing optical system can be tilted. Therefore, according to any one of the first to fifth aspects, it is possible to provide an image pickup apparatus capable of performing high-level shooting such as camera shake correction, one-side blur correction of the imaging optical system, and tilt shooting.

It is a schematic diagram which shows the structure of 1st Embodiment of the optical unit and imaging device in this invention. It is a schematic diagram which shows the structure of the 1st example of a drive element. It is a schematic diagram which shows the structure of the 2nd example of a drive element. It is a schematic diagram which shows the structure of the 3rd example of a drive element. It is a schematic diagram which shows the structure of 2nd Embodiment of the optical unit and imaging device in this invention. It is sectional drawing which shows the structure of 3rd Embodiment of the optical unit in this invention.

  Hereinafter, the present invention will be described based on the illustrated embodiment, but the present invention is not limited to the embodiment. In the drawings, the same or equivalent parts are denoted by the same reference numerals, and redundant description is omitted.

  First, a first embodiment of an optical unit and an imaging device according to the present invention will be described with reference to FIG. 1. FIG. 1 shows a first embodiment of an optical unit 200 and an imaging device 10 according to the present invention. FIG. 1A is a schematic diagram illustrating a configuration, and FIG. 1A is a diagram of the optical unit 200 and the imaging device 10 viewed from the imaging optical system side, and FIG. 1B is a cross-sectional view taken along line AA ′ of FIG. .

  1A and 1B, the imaging device 10 includes an imaging unit 100, an optical unit 200, a drive element 301, and the like. The imaging unit 100 includes an imaging element 111, an imaging substrate 121, an imaging circuit 131, and the like. The optical unit 200 includes an imaging optical system 211, a holding frame 221 of the imaging optical system 211, a lens barrel 231 and the like. The holding frame 221 and the lens barrel 231 function as a lens barrel in the present invention.

  The image pickup device 111 is mounted on one surface of the image pickup substrate 121, and the CPU, circuit components, and the like constituting the image pickup circuit 131 are mounted on the opposite surface.

  The imaging optical system 211 includes, for example, two lenses 211a and 211b, and the lenses 211a and 211b are arranged and fixed in the holding frame 221 at a predetermined interval. The outer periphery of the holding frame 221 and the inner periphery of the lens barrel 231 are threaded, and by screwing the holding frame 221 into the lens barrel 231, focus adjustment of the imaging optical system 211 at the time of assembling the imaging apparatus 10 can be performed. Done. After the focus adjustment, the holding frame 221 and the lens barrel 231 are fixed by adhesion or the like.

  The drive element 301 is disposed between the imaging surface side end surface 231 a of the lens barrel 231 and the imaging element 111 mounting surface 121 a of the imaging substrate 121. The driving element 301 and the lens barrel 231, and the driving element 301 and the imaging substrate 121 are bonded together by, for example, adhesion.

  As will be described later with reference to FIG. 2, when a drive voltage is applied to the drive element 301, the drive element 301 contracts in the direction of the optical axis 201 (Z direction in the figure), and the imaging optical system passes through the lens barrel 231 and the holding frame 221. The autofocus operation is realized by lowering 211 toward the optical axis 201 (Z direction in the figure).

  As described above, according to the first embodiment of the optical unit 200 and the imaging device 10, the optical unit 200 and the imaging unit 100 are directly joined by the drive element 301, and the drive element 301 is light of the optical unit 200. Since the imaging optical system 211 can be driven with the same outer shape as that of the optical unit 200 because it is expanded and contracted in the axial direction, the optical unit 200 and the imaging apparatus 10 suitable for a camera-equipped mobile phone or the like are provided. can do.

  Next, a first example of the drive element 301 described above will be described with reference to FIG. 2A and 2B are schematic views showing the configuration of the first example of the drive element 301. FIG. 2A is a perspective view showing the shape of the drive element 301. FIG. 2B is a cross-sectional view taken along a plane including the optical axis 201. FIG. 2C and FIG. 2D are diagrams showing the driving method.

  2A, in the first example, the drive element 301 has a cylindrical shape that is axially symmetric with respect to the optical axis 201 of the imaging optical system 211, and the end surface of the driving element 301 captures the image of the lens barrel 231 shown in FIG. It has the same shape as the surface side end surface 231a. As described in FIG. 1, the imaging surface side end surface 231a of the lens barrel 231 and the end surface of the drive element 301 are joined by a method such as adhesion.

  2B and 2C, the driving element 301 is a stacked actuator in which cylindrical thin plates are stacked in the direction of the optical axis 201, and includes a first electrode 303, a variable portion 307, a second electrode 305, The variable portion 307 and the first electrode 303 are stacked in this order. Examples of the stacked actuator include, but are not limited to, an electrostrictive polymer actuator and a liquid crystal elastomer. These actuators have a holding function as a structure and can support the optical unit 200.

  In FIG. 2C, a driving power source PS (driving voltage V) is connected between the first electrode 303 and the second electrode 305 via a switch SW.

  In FIG. 2D, when the switch SW is closed, the driving voltage V is applied between the first electrode 303 and the second electrode 305 from the power source PS, and the variable portion 307 contracts, whereby the driving element 301 is contracted. Contracts in the direction of the optical axis 201. The contraction amount of the variable unit 307 is proportional to the magnitude of the drive voltage V of the power source PS. Depending on the type of the drive element 301, the variable unit 307 extends by reversing the direction of the drive voltage V, and the drive element 301 extends in the direction of the optical axis 201. Unlike motors, stacked actuators have almost no drive sound when driven, so that the drive sound of the actuator is not recorded even when used in a video camera or the like.

  Here, an example of the above-described stacked actuator will be described.

  One example of a laminated actuator is an electrostrictive polymer actuator or a dielectric elastomer. For example, it has a structure in which a polymer elastomer is sandwiched between flexible electrodes, and the polymer elastomer is crushed by the attractive force between the electrodes when an electric field is applied between the electrodes, and contracts in the direction of the electrodes. It extends to An example is shown in [Nagata et al., “Frontier of Soft Actuator Development, Aiming at Realization of Artificial Muscle”, page 207, FIG. 12 (NTS Corporation)].

  Another example is a liquid crystal elastomer or a liquid crystal gel actuator. This is achieved by applying an electric field or heat to a liquid crystal gel, which is a structure in which liquid crystal molecules are three-dimensionally bonded, to change from a liquid crystal phase having a regular arrangement to an isotropic phase with disordered alignment. Cause deformation. Depending on the type of liquid crystal, there are, for example, one that contracts in the direction of application of an electric field and one that expands when an electric field is applied. For example, [Nagata et al. “Forefront of Soft Actuator Development, Aiming at Realization of Artificial Muscle” on page 217, FIG. 1 (NTS Corporation)] and [Kyushu Institute of Technology “Artificial Muscle Using Liquid Crystal Elastomer Http: // www. phys. mse. kyutech. ac. jp / elastomer. An example is shown in html (searched on September 12, 2007)].

  As described above, according to the first example of the drive element 301, in addition to the effects of the first embodiment of the imaging device 10, the imaging device 10 having excellent silence can be provided.

  Next, a second example of the driving element 301 will be described with reference to FIG. FIG. 3 is a schematic diagram showing the configuration of the second example of the drive element 301.

  In FIG. 3, the drive element 301 and the lens barrel 231 are integrally formed. In the portion functioning as the drive element 301, as shown in FIG. 2C, the first electrode 303, the variable portion 307, and the second electrode 305 are sequentially stacked. On the other hand, the first electrode 303 and the second electrode 305 are not formed in the portion functioning as the lens barrel 231, and only the same material as the variable portion 307 is laminated.

  With such a configuration, the portion functioning as the driving element 301 applies the driving voltage V between the first electrode 303 and the second electrode 305 as shown in FIG. Thus, the portion that functions as the actuator and functions as the lens barrel 231 on which no electrode is formed does not change the shape, and has two functions of the driving element 301 and the lens barrel 231 while being integrally formed. It becomes possible.

  Examples of the actuator that enables such an integral configuration include the electrostrictive polymer actuator and the liquid crystal elastomer described in the description of FIG. These actuators have a holding function as a structure and can support the optical system.

  As described above, according to the second example of the driving element 301, in addition to the effects of the first embodiment of the optical unit 200 and the imaging device 10 and the first example of the driving element 301, the driving element 301. And the lens barrel 231 can be integrally formed, so that the number of components and manufacturing processes such as an adhesion process can be reduced, and the imaging apparatus 10 excellent in cost reduction can be provided.

  Next, a third example of the drive element 301 will be described with reference to FIG. FIG. 4 is a schematic diagram showing the configuration of the third example of the drive element 301. FIG. 4A is a top view of the drive element 301 and the lens barrel 231 viewed from the lens barrel 231 side, and FIG. And (c) is a BB ′ cross-sectional view of FIG. Here, the lens barrel 231 is shown in a simplified form as the same cylindrical shape as the drive element 301.

  In FIG. 4 (a), the drive element 301 itself is cylindrical, but the first electrode 303 and the second electrode 305 are not formed on the entire surface, and the four partial electrodes 303a at 90 ° intervals, 305a, 303b, 305b, 303c, 305c and 303d, 305d are formed. As a result, the drive element 301 is divided into four partial elements 301a, 301b, 301c, and 301d and four parts that do not function as drive elements between the partial elements.

  4B, the B-B ′ cross section of the drive element 301 and the lens barrel 231 is the same as that of FIG. 2 or FIG. 3 except that the electrodes 303a, 305a and 303b, 305b are partial electrodes. Preferably, as in FIG. 3, the drive element 301 and the lens barrel 231 are integrally formed.

  In FIG. 4C, when the drive voltage V is selectively applied only between the partial electrodes 303a and 305a, only the variable portion 307a contracts and only the partial element 301a contracts. The subelement 301b does not change. As a result, only the upper part of the partial element 301a of the lens barrel 231 is pulled down in the optical axis direction, and as a result, a so-called tilting operation in which the optical axis 201 is tilted in the direction of the arrow R in the drawing becomes possible.

  Here, an example in which the drive voltage V is applied only to the subelement 301a is shown. However, if a different drive voltage V is applied to each of the four subelements 301a, 301b, 301c, and 301d, the optical axis 201 can be tilted in any direction. It becomes possible to do. As a result, not only camera shake correction and one-sided blur correction of the imaging optical system but also advanced shooting such as tilt shooting is possible. Of course, if the same drive voltage V is applied to each of the four subelements, an autofocus operation similar to that shown in the first embodiment of the imaging device 10 can be performed.

  The division of the drive element 301 is not limited to four divisions. For example, the drive element 301 may be divided into three to form an equilateral triangle. In addition, various variations can be considered according to the application.

  As described above, according to the third example of the drive element 301, the optical unit 200 and the imaging device 10 according to the first embodiment, the first example of the drive element 301, and the second example of the drive element 301 are described. In addition to the effect, since the optical axis 201 can be tilted by making the drive element 301 a partial element, imaging capable of advanced shooting such as camera shake correction, one-sided blur correction of the imaging optical system and tilt shooting is possible. An apparatus 10 can be provided.

  Next, a second embodiment of the optical unit and the imaging device according to the present invention will be described with reference to FIG. 5. FIG. 5 shows a second embodiment of the optical unit 200 and the imaging device 10 according to the present invention. FIG. 5A is a schematic view showing the configuration, FIG. 5A is a view of the optical unit 200 and the image pickup apparatus 10 as viewed from the image pickup optical system side, and FIG. 5B is a cross-sectional view taken along the line CC ′ of FIG. .

  The difference between the second embodiment and the first embodiment is that the first embodiment uses a circular imaging optical system 211, a cylindrical holding frame 221, a lens barrel 231 and a driving element 301. In contrast, the second embodiment uses the imaging optical system 211 having the same rectangular shape as that of the imaging element 111, a rectangular tube barrel 231 and a driving element 301. The lens barrel 231 functions as a lens barrel in the present invention.

  In the second embodiment, as an example particularly suitable for downsizing, the imaging optical system 211 has a single lens configuration, the holding frame 221, the lens barrel 231 and the driving element 301 are integrated, and the imaging substrate 121 is integrated. Are the same size as the lens barrel 231 and the drive element 301. As a result, the image pickup apparatus 10 becomes one square lump like a dice, and has an optimum shape especially for mounting on a camera-equipped mobile phone or the like. Also in this example, the drive element 301 shown in FIG.

  As described above, according to the second embodiment of the optical unit 200 and the imaging device 10, the imaging device 10 is configured by using the rectangular imaging optical system 211, the rectangular tube barrel 231, and the drive element 301. The optical unit 200 and the imaging apparatus 10 that can be formed into a single square lump like a dice and are suitable for a camera-equipped mobile phone or the like can be provided.

  Next, a third embodiment of the optical unit 200 according to the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view showing the configuration of the optical unit 200 according to the third embodiment of the present invention. FIG. 6A shows a state in which the drive element 301 is not expanded and contracted, and FIG. 6B shows the drive element. 301 shows a contracted state.

  In FIG. 6A, the optical unit 200 includes an imaging optical system 211 and a lens barrel 241. The imaging optical system 211 is composed of two lenses 211a and 211b, and the lens barrel 241 is composed of a first lens barrel 241a and a second lens barrel 241b. The lens 211a is held by the first lens barrel 241a, and the lens 211b is held by the second lens barrel 241b. A drive element 301 is disposed between the first lens barrel 241a and the second lens barrel 241b. The driving element 301 is a cylindrical stacked actuator similar to that shown in FIG.

  The first lens barrel 241a, the second lens barrel 241b, and the driving element 301 may be separate as shown in FIG. 1 or FIG. 2, or may be integrally formed as shown in FIG. It may be.

  In FIG. 6B, when the driving voltage V is applied to the driving element 301, the driving element 301 contracts, and the distance between the first lens barrel 241a and the second lens barrel 241b, that is, the lenses 211a and 211b. The interval of is narrowed. Thereby, the in-focus position of the imaging optical system 211 can be changed, and an autofocus function can be realized.

  Further, the drive element 301 can be formed as a partial element as shown in FIG. 4, and the optical axis 201 of the imaging optical system 211 can be tilted by the partial element. Can be realized.

  As described above, according to the third embodiment of the optical unit 200, the lenses 211a and 211b are arranged by disposing the drive element 301 between the first lens barrel 241a and the second lens barrel 241b. Can be made variable, and an autofocus function can be realized. Furthermore, by making the drive element 301 into a partial element, it is possible to realize a camera shake correction function at the same time as the autofocus function, and the optical unit 200 and the image pickup apparatus 10 suitable for a compact mobile phone with a camera and the like. Can be provided.

  As a method of forming the driving element 301 or the integrated driving element 301 and the lens barrel 231 described above, (1) a method in which electrodes and variable parts are stacked by printing, and (2) an electrode and variable parts are applied by an inkjet method. (3) A method of laminating a sheet-shaped electrode and a variable portion, and curing by heating or the like after die cutting is conceivable.

  In the operation of the driving element 301 in each of the above-described embodiments, it has been described that the driving element 301 contracts when the driving voltage V is applied. However, the driving element that expands when the voltage is applied (for example, the above-described driving element 301 When using a kind of liquid crystal elastomer), it may be considered as the reverse operation.

  As described above, according to the present invention, the driving element that drives the lens barrel that holds the imaging optical system is provided, and the driving element is expanded and contracted in the optical axis direction of the imaging optical system, so that it is approximately the same as the lens barrel. Therefore, it is possible to provide an optical unit that can drive the imaging optical system with the outer shape of the optical system and is suitable for a camera-equipped mobile phone and the like. In addition, by directly joining the optical unit and the imaging unit with the drive element, and expanding and contracting the drive element in the optical axis direction of the optical unit, the imaging optical system can be driven with the same outer shape as the optical unit, An imaging device that is compact, high-performance, excellent in quietness, and suitable for a camera-equipped mobile phone or the like can be provided.

  The detailed configuration and detailed operation of each component constituting the imaging apparatus according to the present invention can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Imaging device 100 Imaging unit 111 Imaging element 121 Imaging board 131 Imaging circuit 200 Optical unit 201 Optical axis 211 Imaging optical system 211a Lens 211b Lens 221 (Imaging optical system) Holding frame 231 Lens barrel 301 Driving element 303 First electrode 305 First Two electrodes 307 Variable section SW switch PS power supply V drive voltage

Claims (5)

An optical unit having a lens barrel to which an imaging optical system is fixed;
An imaging unit having an imaging device disposed on the optical axis of the imaging optical system;
A drive element having a cylindrical shape and extending and contracting in a direction parallel to the optical axis of the imaging optical system;
With
The drive element is
One end surface of the cylindrical shape is disposed between the lens barrel and the imaging unit, and the other end surface of the cylindrical shape is joined directly to the image surface side end surface of the lens barrel. Supporting the optical unit as a cylindrical structure by being directly joined to the imaging unit,
The drive element is divided into a plurality of partial elements by providing a plurality of partial electrodes along the circumferential direction of the cylindrical shape,
The plurality of partial elements expand and contract in a direction parallel to the optical axis, and the drive element moves the barrel so that the imaging optical system fixed to the barrel is spaced from the optical unit. An image pickup apparatus characterized by changing the angle. The imaging device according to claim 1,
The drive element is
The portion of the partial element of the plurality of partial elements, an imaging apparatus according to claim Rukoto is tilted to the optical axis of the imaging optical system by relatively stretching to other subelements. The imaging device according to claim 1 ,
The drive element is
All equal telescopic imaging apparatus according to claim Rukoto is moved in parallel along the imaging optical system on the optical axis by the plurality of subelements. In the imaging device according to any one of claims 1 to 3,
Each of the plurality of subelements is a stacked type in which a structure having a variable portion that expands and contracts according to an applied voltage and an electrode portion that applies a voltage between both ends of the variable portion is sequentially stacked. An actuator,
Portion other than the plurality of partial elements of the drive element, an imaging apparatus characterized that you have been formed by the same material as the variable portion. The imaging apparatus according to claim 4,
The lens barrel is
Without having an electrode, it is made of the same material as the variable part,
The imaging apparatus, wherein the lens barrel and the driving element are integrally formed.

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