JP2008164920A - Imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging device capable of achieving space saving. <P>SOLUTION: In the imaging device 1, a coupling means 12 coupling a movable part 4 with a fixed part 10 includes an attaching part 13 fixed at the fixed part 10, and an electrostriction polymer element 14 extending in an optical axis direction, having one end coupled with the movable part 4 and the other end coupled with the attaching part 13, and provided with electrode parts 14a and 14b. In such a case, the movable part 4 provided with a lens 6, the fixed part 10 provided with an imaging element 8 and the electrostriction polymer element 14 are arrayed in an optical axis L direction, so that the imaging device is miniaturized without making width (for example, diameter) in a direction orthogonal to an optical axis L large. Thus, the space saving in various devices (for example, cellular phone or digital camera) is achieved. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image pickup apparatus that is reduced in size for mounting on devices such as a digital camera and a camera-equipped mobile phone, and that enables focusing by a lens that can advance and retreat in the optical axis direction.

  Conventionally, there is JP, 2004-159425, A as a technique of such a field. In the lens driving unit described in this publication, the screw shaft can be rotated forward and backward by the vibrating body, and the focusing function is achieved by the lens of the driven part screwed to the screw shaft moving forward and backward in the optical axis direction. Is done. This lens drive unit does not require an electromagnetic motor or the like, and can simplify the structure, so that it can be applied to a mobile phone or the like.

JP 2004-159425 A JP 7-274544 A

  However, the above-described conventional lens drive unit requires a screw shaft and a guide rail, and a drive source is provided adjacent to the screw shaft, so that a storage space for the guide shaft and the like is required, which increases the size of the lens drive unit. There is a problem of being invited.

  In particular, an object of the present invention is to provide an imaging apparatus capable of saving space.

  An imaging apparatus according to the present invention is an imaging apparatus that enables focusing by a lens that can advance and retreat in the optical axis direction, and includes a movable part having a lens disposed on the optical axis, and an imaging element disposed on the optical axis. And a connecting means for connecting the movable part and the fixed part. The connecting means extends in the direction of the optical axis and has one end connected to the movable part. And an electrostrictive polymer element having the other end connected to the mounting portion and provided with an electrode portion.

  In this imaging apparatus, since the movable part provided with the lens, the fixed part provided with the imaging element, and the electrostrictive polymer element are aligned in the optical axis direction, the imaging apparatus relates to the optical axis. The size of the imaging apparatus can be reduced without increasing the length (for example, the diameter) in the orthogonal direction. As a result, it is possible to save space in a device (for example, a mobile phone).

  The electrostrictive polymer element is preferably composed of a plurality of arm portions extending in the optical axis direction, and the arm portions are preferably arranged at equal intervals. When such a configuration is adopted, the amount of force required to drive the movable portion can be easily changed according to the application by simply changing the number of arm portions forming the electrostrictive polymer element.

  Further, it is preferable that the mounting portion is formed in a band shape, and the electrostrictive polymer element extends in a direction orthogonal to the long side of the mounting portion. When such a configuration is adopted, an assembling operation can be performed in which the belt-shaped mounting portion is wound around the outer peripheral surface of the fixed portion.

  According to the present invention, it is possible to save space, that is, to reduce the size, and at the same time, to reduce the weight.

  Hereinafter, preferred embodiments of an imaging apparatus according to the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 to 3, the imaging device 1 is a camera unit that can be focused and miniaturized to be mounted on a device such as a small digital camera or a mobile phone with a camera. The imaging apparatus 1 has a cylindrical lens barrel 2, and a circular imaging window 2 a is formed at the end of the lens barrel 2. A concave lens 3 is attached to the lens barrel 2 so as to close the imaging window 2 a. It is fixed. In the lens barrel 2, a movable portion 4 that slides in the direction of the optical axis L is disposed. The movable portion 4 is a cylindrical slider 5 and a convex lens that is disposed on the optical axis L and fixed on the inner surface of the slider 5. 6 and. Further, a reduced diameter portion 5 a is provided at the lower end of the slider 5.

  In the lens barrel 2, a compression coil spring 7 is disposed between the tip of the slider 5 and the top 2 b of the lens barrel 2, and the slider 5 is urged by the spring 7. The imaging device 1 employs an imaging device (for example, a CMOS sensor) 8 applicable to a mobile phone or the like, and the imaging device 8 is fixed on a circuit board 9. The fixing unit 10 includes an imaging element 8 provided on the circuit board 9, a cylindrical base part 11 fixed on the circuit board 9 so as to cover the imaging element 8, and the base part 11 above the imaging element 8. And a concave lens 15 fixed to the inner surface of the lens. Furthermore, the lower end of the lens barrel 2 is fixed to the ring-shaped seating surface 11 a at the upper end of the base portion 11 with an adhesive. It should be noted that the outer shape of the lens barrel 2 and the outer shape of the base portion 11 have the same shape, thereby achieving slimming.

  Further, the movable portion 4 and the fixed portion 10 are connected by a connecting means 12 that forms a lens driving portion. The connecting means 12 is connected to the ring-shaped mounting portion 13 fitted to the ring-shaped reduced diameter portion 11 b provided at the upper end of the base portion 11 of the fixed portion 10, and the upper edge of the mounting portion 13 to be connected to the optical axis L. And four arm portions 14 extending in the direction. Further, the mounting portion 13 is formed in a band shape, and the arm portion 14 extends in a direction orthogonal to the peripheral edge of the mounting portion 13. The four arm portions 14 are formed integrally with the mounting portion 13 and are arranged at equal intervals on the periphery of the mounting portion 13.

  Each arm portion 14 is composed of an electrostrictive polymer element in which electrode portions 14a and 14b having a thickness of several μm are printed on the front and back surfaces of a plate-like electrostrictive polymer material having a thickness of several hundred μm. And the arm part 14 expand | extends by applying a predetermined voltage to each of electrode part 14a, 14b provided in the surface and the back surface of the electrostrictive polymer element 14. FIG.

  Here, as a manufacturing method of the connecting means 12, the mounting portion 13 and the arm portion, that is, the base material 14c of the electrostrictive polymer element 14 are integrally formed with an electrostrictive polymer material having a thickness of several hundreds μm. Electrode portions 14a and 14b are printed on the front and back surfaces of the material 14c. In consideration of the adhesiveness between the reduced diameter portion 5a of the slider 5 and the arm portion, that is, the electrostrictive polymer element 14, the electrode portions 14a and 14b are printed on the base material 14c so that the free end of the base material 14c is exposed. Is done. This electrostrictive polymer material is also called an electric field responsive polymer artificial muscle (EPAM), and has a very high stretch rate characteristic.

  As a manufacturing method of other connecting means (not shown) in which the mounting portion and the arm portion are separated, a ring-shaped mounting portion made of an electrical insulating material (polycarbonate, mylar film, etc.) having a thickness of about 1 mm is used. You may fix the lower end of the four arm parts in which the electrode part was formed in the electrostrictive polymer material of several hundred micrometers through an adhesive agent or melt | fusion.

  By applying a predetermined voltage to each electrode part 14a, 14b of each arm part 14 configured in this way, the arm part 14 expands, and power supply to each electrode part 14a, 14b is cut off, so that the arm part 14 contracts back to its original state. In addition, when a voltage is applied to the electrode portions 14a and 14b, the coil spring 7 is compressed by the slider 5, the convex lens 6 is separated from the image sensor 8, and the energization to the electrode portions 14a and 14b is interrupted. The slider 5 is biased by the coil spring 7 and the convex lens 6 returns to the original position while approaching the image sensor 8.

  The electrode portions 14a and 14b provided on each arm portion 14 are connected to wiring on the circuit board 9 via lead wires 16 (see FIG. 1), and plus is applied to the electrode portions 14a by the lead wires 16. The electrode portion 14b is grounded. In addition, the amount of force required to drive the movable portion 4 can be easily changed according to the application simply by changing the number of the arm portions 14 as appropriate. Further, when the focus is adjusted, the amount of movement of the convex lens 6 can be easily adjusted by changing the voltage value applied to the electrode portions 14a and 14b.

  In the imaging apparatus 1 described above, the movable part 4 provided with the convex lens 6, the fixed part 10 provided with the imaging element 8, and the electrostrictive polymer element 14 are aligned in the optical axis L direction. With respect to the apparatus 1, the length in the direction orthogonal to the optical axis L, that is, the diameter is not increased, and the light and thin coupling means 12 can be disposed in the lens barrel 2 of the imaging apparatus 1. The apparatus 1 can be reduced in size and weight. As a result, it is possible to save space in the device (for example, a mobile phone) and to reduce the weight of the device itself.

  Further, the connecting means 12 has a crown shape and is excellent in assembling workability. In addition, since the connecting means 12 is provided with the ring-shaped mounting portion 13, the workability of assembling the base portion 11 to the ring-shaped reduced diameter portion 11b is improved. The ring-shaped mounting portion 13 is fitted into the reduced diameter portion 11b of the base portion 11, and is fixed to the outer peripheral surface of the reduced diameter portion 11b by fusion or an adhesive.

  It goes without saying that the present invention is not limited to the embodiment described above.

  For example, as shown in FIG. 5, in the connecting means 20 according to another embodiment, the mounting portion 21 made of an electrostrictive polymer material is formed in a linear strip shape, and the length of the mounting portion 21 is the fixed portion 10. Is substantially the same as the length of the circumference of the reduced diameter portion 11b of the base portion 11, but can be mounted even if it is short. Furthermore, each arm part (electrostrictive polymer element) 22 provided with the electrode parts 14 a and 14 b extends in a direction orthogonal to the long side of the mounting part 21. Then, as shown in FIG. 6, the belt-like mounting portion 21 is wound around the outer peripheral surface of the reduced diameter portion 11b of the base portion 11 in the fixing portion 10, and is fixed to the reduced diameter portion 11b by fusion or adhesive. . At this time, the arm portions 22 are arranged at equal intervals in the circumferential direction.

  Here, as a manufacturing method of the connecting means 20, the mounting portion 21 and the arm portion, that is, the base material 22c of the electrostrictive polymer element 22 are integrally formed by punching a plate-like electrostrictive polymer material having a thickness of several hundred μm. (See FIG. 7A). Thereafter, the electrode portions 14a and 14b are printed on the front surface and the back surface of the base material 22c, respectively (see FIG. 7B). According to such a manufacturing method, molding by punching is possible, which is suitable for mass production. Moreover, it is possible to easily cope with a design change in the circumferential length of the reduced diameter portion 11b of the base portion 11.

  As shown in FIG. 8, the connecting means 30 according to still another embodiment includes a band-shaped mounting portion 31 made of an electrical insulating material (polycarbonate, mylar film, etc.) having a thickness of about 1 mm, and an adhesive or It consists of four rectangular arm parts 32 fixed through fusion. The arm portion 32 is composed of an electrostrictive polymer element in which electrode portions 14a and 14b having a thickness of several μm are printed on the front and back surfaces of a plate-like electrostrictive polymer material having a thickness of several hundreds of μm. With such a configuration, the number of the arm portions 32 can be easily changed with respect to the mounting portion 31 having a certain length.

  Here, as a manufacturing method of the connecting means 30, a band-shaped mounting portion 31 is formed by punching a plate-shaped electrical insulating material having a thickness of 1 mm, and a plate-shaped electrostrictive polymer material having a thickness of several hundred μm is formed. The base portion 32c of the arm portion, that is, the electrostrictive polymer element 32 is formed by punching, and then the electrode portions 14a and 14b having a thickness of several μm are respectively printed on the front surface and the back surface of the base material 32c (see FIG. 8A). ). Thereafter, one end (lower end) of each arm portion 32 is fixed to the long side portion of the mounting portion 31 via an adhesive or fusion (see FIG. 8B).

  In printing the electrode portions 14a and 14b, in consideration of the adhesiveness between the reduced diameter portion 5a of the slider 5 and the arm portion, that is, the electrostrictive polymer element 32, one end (upper end) of the base material 32c is exposed to attach the mounting portion. The other end (lower end) of the base material 32c is exposed in consideration of the adhesiveness between the arm 31 and each arm 32 (see FIG. 8A).

  Note that the shape and number of the arm portions 14, 22, and 32 are not limited to the above-described embodiment.

It is sectional drawing which shows one Embodiment of the imaging device which concerns on this invention. It is a disassembled perspective view of the imaging device shown in FIG. FIG. 3 is an exploded cross-sectional view of the imaging apparatus illustrated in FIG. 2. It is a principal part expansion perspective view of the imaging device shown in FIG. It is a perspective view which shows the connection means applied to other embodiment of the imaging device which concerns on this invention. It is a perspective view which shows the state which mounted | wore the fixing | fixed part with the connection means. It is a top view which shows the assembly procedure of the connection means shown in FIG. It is a top view which shows the assembly procedure of another connection means.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Imaging device, 4 ... Movable part, 6 ... Convex lens, 8 ... Imaging element (CMOS sensor), 10 ... Fixed part, 12, 20, 30 ... Connection means, 13, 21, 31 ... Mounting part, 14, 22, 32 ... Electrostrictive polymer element (arm part), 14a, 14b ... Electrode part, L ... Optical axis.

Claims (3)

In an imaging device that enables focusing by a lens that can advance and retract in the optical axis direction,
A movable part having the lens arranged on the optical axis;
A fixed portion having an image sensor disposed on the optical axis;
Connecting means for connecting the movable part and the fixed part;
The connecting means includes
A mounting portion fixed to the fixing portion;
And an electrostrictive polymer element having one end connected to the movable portion, the other end connected to the mounting portion, and an electrode portion. .   The imaging device according to claim 1, wherein the electrostrictive polymer element includes a plurality of arm portions extending in the optical axis direction, and the arm portions are arranged at equal intervals. The imaging apparatus according to claim 1, wherein the mounting portion is formed in a belt shape, and the electrostrictive polymer element extends in a direction orthogonal to a long side of the mounting portion.

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