JP2012128138A - Image pickup apparatus and control method of image pickup apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image pickup apparatus capable of driving imaging means at a small driving force and retaining a radiation efficiency of heat generated from the imaging means.SOLUTION: An arm portion 4a of a lead frame 4 extending from an image pickup device 3, and an arm portion 5a of a sheet metal 5 are connected such that the plane part 4b of the lead frame 4 and the plane part 5b of the sheet metal 5 are parallel to each other. The plane part 5b includes an elastic member that is driven by piezoelectric elements 7a and 7b to be bent forward/backward along the optical axis.

Description

  The present invention relates to an imaging apparatus and a method for controlling the imaging apparatus.

  With regard to a single lens reflex type interchangeable lens digital camera, a product having a moving image shooting function in addition to a still image shooting function has been proposed. An image pickup apparatus having a contrast detection type autofocus mechanism (hereinafter referred to as contrast AF) advantageous for moving image shooting has been developed.

  As an image pickup apparatus provided with contrast AF, an image pickup apparatus provided with a moving mechanism of an image pickup element in a camera body in addition to a focus lens moving mechanism in an interchangeable lens has been proposed. The imaging apparatus determines the focusing direction of the lens by causing the imaging element to perform a wobbling operation in the imaging optical axis direction, and scans the focus lens based on the determination result to execute the focusing operation.

  On the other hand, in an image pickup apparatus having an action shooting function, it is important to efficiently dissipate heat generated from the image pickup element in order to suppress the generation of thermal noise due to the temperature rise of the image pickup element. For example, a conventional imaging device that does not include an imaging element moving mechanism dissipates heat generated by the imaging element by conducting heat to a metal plate fixed to the imaging element.

  In addition, Patent Document 1 includes an image sensor fixed to a metal plate (base) having a heat dissipation function, and drives the image sensor together with a metal plate on a plane orthogonal to the optical axis to correct the camera shake that performs heat dissipation. A mechanism is disclosed.

JP 2008-064863 A

  In the technique disclosed in Patent Document 1, since the imaging unit (imaging element) is fixed to the metal plate, the mass and size of the driving object to be driven together with the imaging unit are large. Therefore, there is a problem that the driving force for driving the imaging means has to be increased. On the other hand, for example, when the metal plate is simply reduced in size, the heat dissipation area of the metal plate is reduced, so that there is a problem that the heat dissipation efficiency of the heat generated from the imaging means through the metal plate is lowered.

  An object of the present invention is to provide an image pickup apparatus that can drive the image pickup means with a small driving force and can maintain the heat radiation efficiency of heat generated from the image pickup means.

  An imaging apparatus according to an embodiment of the present invention includes an imaging unit, a holding unit that holds the imaging unit, an elastic support unit that elastically supports the holding unit, a heat dissipation unit provided in the elastic support unit, Drive means for moving the imaging means in a direction along the optical axis by elastically deforming the elastic support means.

  According to the imaging apparatus of the present invention, the imaging unit can be driven with a small driving force, and the heat dissipation efficiency of the heat generated from the imaging unit can be maintained.

1 is a diagram (1) illustrating a configuration of an imaging apparatus according to a first embodiment. 2 is a diagram (2) illustrating a configuration of an imaging apparatus according to Embodiment 1. FIG. FIG. 3 is a diagram (3) illustrating a configuration of the imaging apparatus according to the first embodiment. 2 is a diagram illustrating a configuration of an imaging apparatus according to Embodiments 2 and 3. FIG.

  1 to 3 are diagrams illustrating the configuration of the imaging apparatus according to the first embodiment of the present invention. FIG. 1 shows an example of the internal configuration of a photographic lens. FIG. 1A is a horizontal cross-sectional top view of the main part of the imaging apparatus. FIG. 1B is a vertical cross-sectional view of a main part of the imaging device. FIG. 2 is an external perspective view of the main part of the imaging apparatus. FIG. 2A is an external perspective view seen from the front of the main part of the imaging device. FIG. 2B is an external perspective view of the main part of the imaging device as viewed from the back side. FIG. 3 is a top view of a horizontal section of the main part of the imaging apparatus, and shows an operation example of a mechanism for moving the imaging device in the optical axis L direction. FIG. 3A illustrates an example of a state of the imaging device in which the imaging element is at the reference position. In this example, the position where the image pickup surface of the image pickup device 3 is on the planned coupling surface P of the photographing lens (not shown) is the reference position of the image pickup device 3. FIG. 3B shows an example of a state in which the image sensor has advanced. FIG. 3C illustrates an example of a state in which the imaging element is retracted.

  The image pickup apparatus shown in FIGS. 1 to 3 generates image information by photoelectrically converting a subject image using an image pickup device such as a CCD sensor or a CMOS sensor, and stores the image information in an electronic recording medium such as an arbitrary memory. A digital imaging device for recording. CCD is an abbreviation for Charge Coupled Device. CMOS is an abbreviation for Complementary Metal Oxide Semiconductor. 1 to 3, reference numeral 1 denotes a main body which is an imaging device. 1 a is a lens mounting surface (mounting portion) of the main body 1. Reference numeral 2 denotes a sensor base plate, which includes a mechanism for moving the image sensor 3 (hereinafter referred to as an image sensor movement mechanism).

  The sensor base plate 2 is attached to the main body 1 so that the height of the sensor base plate 2 can be adjusted, for example, by sandwiching an adjustment washer 2a at a predetermined location. As a result, the sensor base plate 2 is maintained at a position at a predetermined distance from the mount portion 1a and has a flatness perpendicular to the optical axis of the imaging optical system (imaging lens).

  The imaging element 3 functions as an imaging unit that forms an image of a light beam from a subject. The image pickup device 3 has an external package such as a ceramic material, and converts an image projected on the image pickup surface inside the image pickup device into an electric signal. Since this imaging surface is on the planned imaging surface of the lens, a focused image is captured. In the following description, an image sensor packaged is described as an image sensor package.

  The imaging device 3 has a so-called electronic shutter function, and has an electronic front curtain functioning as an electronic shutter for starting image signal capture and an electronic rear curtain function for stopping capture. That is, it is possible to start accumulation of image charges by the operation of the electronic front curtain, and to end the accumulation after a predetermined time by the operation of the electronic rear curtain. Thereafter, the image sensor 3 performs an operation of reading the accumulated image charge and transmits an image signal to a signal processing circuit (not shown).

  A lead frame 4 is extended from the image sensor 3. The lead frame 4 functions as a holding unit that holds the image sensor 3. The lead frame 4 is a metal plate that is integrally formed with the image pickup device package and includes a terminal (lead) that outputs an image pickup signal to the outside. The lead frame 4 has a substantially U shape. Specifically, the lead frame 4 has a flat surface portion 4b and an arm portion 4a bent to a substantially diameter. The flat surface portion 4 b is a first flat surface portion that extends from the image sensor 3 along the longitudinal direction of the image sensor 3.

  The arm portion 4a is a first bent portion that forms a predetermined angle (substantially a right angle in this example) with the first plane portion (plane portion 4b). The tip of the arm portion 4a is formed so that the flat surface portion 5b of the metal plate 5 and the flat surface portion 4b of the lead frame 4 are parallel, that is, the flat surface portion 5b and the imaging surface of the image sensor 3 are parallel. 5 is fixed to the arm 5a with high accuracy by soldering. As a result, the image pickup surface of the image pickup device 3 is prevented from tilting, and the image pickup device 3 can move along the optical axis L along with the bending deformation of the flat portion of the sheet metal 5 described later.

  The elastic support means 5 elastically supports the lead frame 4. The elastic support means 5 is an elastic member (for example, a sheet metal). Hereinafter, the elastic support means 5 is also referred to as a sheet metal 5. In this example, the sheet metal 5 is formed by bending and processing a rectangular plate material made of 42 alloy material which is an alloy of nickel and iron having elasticity. The sheet metal 5 has a substantially U-shape. Specifically, the sheet metal 5 includes a central plane portion 5b and arm portions 5a bent at substantially right angles at both ends. The flat surface portion 5b is a second flat surface portion provided with a counterweight 8 described later. The arm portion 5a is a second bent portion that forms a predetermined angle (substantially a right angle in this example) with the second plane portion (plane portion 5b).

  The sheet metal 5 is soldered and fixed to the arm part 4a of the lead frame with high accuracy in a state where the imaging surface of the image sensor 3 and the flat surface part 5b of the sheet metal 5 are substantially parallel at the tip of the arm part 5a. A pair of piezoelectric elements 7 a and 7 b are attached to the front and back surfaces of the flat portion 5 b of the sheet metal 5. And the plane part 5b of the sheet metal 5 is elastically deformed by expanding and contracting the piezoelectric elements 7a and 7b to which voltage is applied. As a result, the sheet metal 5 bends in the front-rear plate thickness direction (direction along the optical axis) with the central portion thereof being the center while keeping the imaging surface of the image sensor 3 parallel. That is, the plane portion 5b is driven by the piezoelectric elements 7a and 7b and bends back and forth along the optical axis L.

  By connecting the lead frame 4 of the image sensor directly to the sheet metal 5, it is possible to efficiently secure a heat radiation path without connecting a dedicated heat radiating member to the image sensor. Heat generated while the image sensor 3 is operating, such as during shooting, is transmitted through the lead frame 4 to the sheet metal 5.

  Further, an A / D conversion IC for A / D (analog / digital) conversion of the signal output of the image sensor 3 is provided on the back surface of the image sensor 3. Heat generated by the A / D conversion IC is transmitted from the image pickup device package to the sheet metal 5 via the lead frame 4. Thereby, the heat generated around the image sensor 3 is efficiently radiated.

  The sheet metal 5 is joined and fixed to the fulcrum 6 at a predetermined joint. The fulcrum 6 is a pair of support members that sandwich the sheet metal 5 from above and below in the drawing. The fulcrum 6 is attached to the sensor base plate 2 so as to be adjustable, with the four fulcrum adjustment plates 6a interposed therebetween. Thereby, as shown to FIG. 3 (A), the position of the imaging surface of the image pick-up element 3 is adjusted to the position of the plan coupling surface P of a photographing lens.

  That is, the fulcrum 6 functions as a support unit that supports the flat portion 5b at a predetermined support point (fulcrum 6) and adjusts the reference position of the image sensor 3. Two (four in total) fulcrum adjusting plates 6 a are provided at each end of the fulcrum 6 in the short direction of the sheet metal 5. Further, the fulcrum 6 supports the sheet metal 5 and the image sensor 3 so as not to hinder the bending deformation of the piezoelectric element 7 at a position substantially equidistant from the center of the sheet metal 5.

  The piezoelectric elements 7a and 7b are driving means for moving the image pickup element 3 in a direction along the optical axis by elastically deforming the flat portion 5b of the sheet metal 5. In this example, the piezoelectric elements 7a and 7b are thin plate-shaped piezoelectric ceramic elements made of PZT or the like. The piezoelectric element 7 a is attached to the surface of the flat portion 5 b of the sheet metal 5. The piezoelectric element 7 b is attached to the back surface of the flat portion 5 b of the sheet metal 5. A circuit (not shown) included in the imaging apparatus controls the magnitude of the voltage applied to the piezoelectric elements 7a and 7b and the direction in which the current flows. Thereby, the expansion / contraction direction and expansion / contraction amount of the piezoelectric element are controlled. In this example, a constant voltage is applied to the upper and lower piezoelectric elements by a parallel connection method, and the upper and lower piezoelectric elements expand and contract in opposite directions.

  For example, application of a plus voltage causes the piezoelectric element 7a to expand and contract and the piezoelectric element 7b expands. Therefore, as shown in FIG. 3B, the sheet metal 5 bonded together is deformed so that the front side is recessed, and the image sensor 3 moves forward. Further, the application of a minus voltage causes the piezoelectric element 7a to expand and the piezoelectric element 7b to contract. Therefore, as shown in FIG. 3C, the sheet metal 5 bonded together is deformed so that the front side protrudes, and the image sensor 3 moves backward. That is, when a voltage is applied to the piezoelectric element, a displacement occurs between the center part of the flat part 5b of the metal plate 5 and the tip part of the arm part 5a with the fulcrum 6 as a fulcrum, and the imaging element moves along the optical axis L. To do. Note that the amount of displacement of expansion or contraction of the piezoelectric element can be controlled by adjusting the magnitude of the applied voltage.

  The counterweight 8 functions as a heat radiating means. In this example, the counterweight 8 is made of a material having a large specific gravity and good heat dissipation, such as brass. The counterweight 8 includes a plurality of heat radiating fins. Note that the weight of the counterweight 8 is the same as the mass of the image sensor 3. In the present embodiment, the counterweight 8 is a material with good heat dissipation and is provided with heat dissipation fins, and thus is effective as a heat sink. Therefore, the heat generated around the image pickup device 3 is finally radiated efficiently by the heat sink effect of the counterweight 8.

  The counterweight 8 is provided on the back surface of the flat portion 5b on the outer side in the extending direction of the back surface than the region where the piezoelectric element 7b is provided. Specifically, as shown in FIG. 1B, the counterweight 8 is fixed to the sheet metal 5 at the counterweight attachment position 10 with only the upper and lower two points at the center of the back surface of the flat portion 5b as attachment positions. . Therefore, the attachment of the sheet metal 5 of the counterweight 8 does not affect the bending deformation of the sheet metal 5 by the piezoelectric element.

  That is, the sheet metal 5, the fulcrum 6, and the piezoelectric elements 7a and 7b constitute an image sensor moving mechanism that moves the image sensor 3 in the direction along the optical axis. In this imaging element moving mechanism, when the piezoelectric element 7 expands and contracts due to voltage application, the flat portion 5b of the sheet metal 5 is bent and deformed, but the arm portion 5a moves back and forth. Therefore, the image sensor 3 moves forward or backward along the optical axis L from the flange back position while maintaining the imaging surface orthogonal to the optical axis L. At the same time, the counterweight 8 moves backward or forward, and the image sensor 3 and the counterweight 8 move in opposite directions.

  The stroke of the image sensor moving mechanism can be controlled by voltage control. As the amount of bending deformation of the sheet metal 5 is changed by voltage control to the piezoelectric elements 7a and 7b, the stroke in which the imaging element 3 moves back and forth changes.

  On the other hand, by adjusting the distance between the two fulcrums 6 in the longitudinal direction of the sheet metal 5, the ratio of the stroke in which the image sensor 3 moves and the stroke in which the counterweight 8 moves can be adjusted. Further, in the short direction of the sheet metal 5, by twisting the sheet metal 5 by changing the height of the fulcrum 6 along the optical axis by the fulcrum adjusting plate 6 a, how the imaging surface of the image sensor 3 is tilted changes. . As described above, by finely adjusting the position of the fulcrum 6 in the front-back direction, left-right direction, or tilting direction, the imaging surface of the imaging device 3 is not inclined with respect to the optical axis, even if there is a manufacturing variation in parts. It can be adjusted to be located at the reference position of the distance.

  The image pickup apparatus of the present embodiment moves the image pickup element 3 in the direction along the optical axis by bending and deforming the flat portion 5b of the metal plate 5 which is an elastic support member by a driving means. Therefore, according to the imaging apparatus of the present invention, the imaging means can be driven with a small driving force. In addition, the image pickup apparatus according to the present embodiment transfers heat generated from the image pickup element 3 to the counterweight 8 provided on the flat portion 5b of the sheet metal 5 via the lead frame 4 to dissipate heat. It can be kept large enough. As a result, the heat generated from the imaging means can be efficiently radiated.

  FIG. 4 is a configuration example of the imaging apparatus according to the second and third embodiments. FIG. 4A illustrates a configuration example of the imaging apparatus according to the second embodiment. The imaging device 31 provided in the imaging device has an outer portion pressed against the plate 12 by the connecting member 11. The outer shape of the image sensor 31 is made of, for example, ceramic. The plate 12 includes a planar portion 12b extending along the longitudinal direction of the image sensor 3, and an arm portion 12a that forms a predetermined angle (substantially a right angle in this example) with the planar portion 12b. The connection member 11 is a connection member that connects the imaging device 3 and the flat surface portion 12b. That is, in the second embodiment, the plate 12 and the connection member 11 function as a holding unit that holds the image sensor 3.

  The arm 12a is soldered and fixed to the arm 5a in the same manner as the arm 4a of the lead frame 4 shown in FIG. Thereby, the heat generated from the image sensor 3 is transmitted to the flat portion 5b of the sheet metal 5 via the connection member 11 and the plate 12, and is radiated. Note that, among the constituent elements included in the imaging device according to the second embodiment, those having the same reference numerals as the constituent elements included in the imaging device according to the first embodiment have the same functions as the constituent elements included in the imaging device according to the first embodiment.

  According to the image pickup apparatus of the second embodiment, even when the image pickup apparatus has a configuration in which the outer portion of the image pickup element 3 must be directly held by using a frame (in this example, the plate 12) other than the lead frame, the image pickup is performed. Heat can be efficiently radiated from the element 3.

  FIG. 4B illustrates a configuration example of the imaging apparatus according to the third embodiment. This imaging apparatus includes an imaging element 32 packaged with a resin member having rigidity lower than that of ceramic mainly from the viewpoint of cost reduction. That is, in this embodiment, the image sensor package is a package member that packages the image sensor 32 with a resin member. The flat surface portion 12b of the plate 12 extends along the longitudinal direction of the image sensor package. Further, for the purpose of reinforcement and heat dissipation, the image sensor auxiliary frame 13 is integrally formed in the image sensor package. That is, the image sensor auxiliary frame 13 functions as a connecting member that connects the image sensor package and the flat surface portion 12b.

  The arm portion 12a is soldered and fixed to the arm portion 5a. Thereby, the heat generated from the image pickup device 3 is transmitted to the flat portion 5b of the sheet metal 5 through the image pickup device auxiliary frame 13 and the plate 12, and is radiated. Note that, among the constituent elements included in the imaging apparatus according to the third embodiment, those having the same reference numerals as the constituent elements included in the imaging apparatus according to the first embodiment have the same functions as the constituent elements included in the imaging apparatus according to the first embodiment.

  According to the third embodiment, even when the image pickup device is configured to be packaged with a resin member, the heat generated from the image pickup device 3 is transmitted to the sheet metal 5 through the image pickup device auxiliary frame 13 and the plate 12 to improve efficiency. Heat can be released.

(Other examples)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed. In this case, the program and the storage medium storing the program constitute the present invention.

DESCRIPTION OF SYMBOLS 1 Main body 2 Sensor base plate 3 Image pick-up element 4 Lead frame 5 Sheet metal 6 Support point 7 Piezoelectric element 8 Counterweight

Claims (8)

Imaging means;
Holding means for holding the imaging means;
Elastic support means for elastically supporting the holding means;
A heat dissipating means provided in the elastic support means;
An image pickup apparatus comprising: drive means for moving the image pickup means in a direction along an optical axis by elastically deforming the elastic support means. The holding means includes a first plane portion extending from the imaging means along the longitudinal direction of the imaging means, and a first bent portion forming a predetermined angle with the first plane portion,
The elastic support means includes a second flat surface portion provided with the heat dissipation means, and a second bent portion having a predetermined angle with the second flat surface portion,
The first bent portion and the second bent portion are connected so that the first plane portion and the second plane portion are parallel to each other,
The imaging apparatus according to claim 1, wherein the second planar portion includes an elastic member that is driven by the driving unit and bends back and forth along the optical axis. The holding means includes a first flat portion extending along a longitudinal direction of the imaging means, a first bent portion having a predetermined angle with the first flat portion, the imaging means, and the first A connecting member for connecting the flat portion of 1;
The elastic support means includes a second flat surface portion provided with the heat dissipation means, and a second bent portion having a predetermined angle with the second flat surface portion,
The first bent portion and the second bent portion are connected so that the first plane portion and the second plane portion are parallel to each other,
The imaging apparatus according to claim 1, wherein the second planar portion includes an elastic member that is driven by the driving unit and bends back and forth along the optical axis. The imaging means includes a package member in which an imaging element is packaged with a resin member,
The holding means includes a first plane portion extending along a longitudinal direction of the package member, a first bent portion that forms a predetermined angle with the first plane portion, the package member, and the first member. A connecting member for connecting the flat portion of 1;
The elastic support means includes a second flat surface portion provided with the heat dissipation means, and a second bent portion having a predetermined angle with the second flat surface portion,
The first bent portion and the second bent portion are connected so that the first plane portion and the second plane portion are parallel to each other,
The imaging apparatus according to claim 1, wherein the second planar portion includes an elastic member that is driven by the driving unit and bends back and forth along the optical axis. 5. The imaging according to claim 2, wherein the driving unit is a pair of piezoelectric elements that are provided on a front surface and a back surface of the second planar portion and expand and contract by voltage application. apparatus. The imaging apparatus according to claim 5, wherein the heat radiating unit is provided on the back surface of the second flat surface portion outside the region where the piezoelectric element is provided in the extending direction of the back surface. The imaging apparatus according to any one of claims 2 to 6, further comprising support means for supporting the second plane portion at a predetermined support point and adjusting a reference position of the imaging means. . Imaging means, holding means for holding the imaging means, elastic support means for elastically supporting the holding means, heat radiation means provided in the elastic support means, and drive means for driving the elastic support means A method for controlling an imaging apparatus,
The method for controlling an imaging apparatus, comprising: a step in which the driving unit moves the imaging unit in a direction along an optical axis by elastically deforming the elastic support unit.

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