JP2011146856A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital camera that ensures excellent heat dissipation capability even when a wiring board with an imaging IC mounted thereon moves. <P>SOLUTION: The digital camera includes: a rigid flexible wiring board 43 having an imaging element mounting part 43a and an imaging IC mounting part 43b connected by a flexible part 43d, the imaging IC mounting part 43b being connected with a board connector mounting part 43c are connected by a flexible part 43e; and heat sinks 52, 4 for fixing the wiring board 43 by clamping the board back surface of the imaging IC mounting part 43b and the surface of the imaging IC 45 through elastic heat conductive sheets 53, 51, respectively. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an imaging apparatus such as a digital camera, a video camera, and a mobile phone.

  In recent years, in this type of image pickup apparatus, an increase in the number of pixels of an image sensor such as a CCD sensor or a CMOS sensor has progressed, and large-capacity data processing and transfer are performed at the time of taking a still image or a moving image. For this reason, power consumption of circuit components such as an imaging IC that performs A / D conversion of image data on a circuit board and a video engine that controls image processing and imaging equipment tends to increase. If the circuit components become hot, the reliability of the circuit components decreases, and the captured image is also affected by thermal noise. For this reason, it is necessary to provide a heat dissipation structure in the imaging device to efficiently release the heat of the circuit components to the outside.

  A conventional heat dissipation structure of a digital camera will be described with reference to FIGS. 9 is a perspective view showing a rigid flexible wiring board (hereinafter referred to as a “rigid flexible wiring board”) on which an imaging element and an imaging IC are mounted, FIG. 10 is an exploded perspective view of a digital camera, and FIG. FIG.

  In FIG. 10, the rigid flexible wiring board 105 includes rigid portions 105a, 105b, and 105c and flexible portions 105d and 105e. The flexible part 105d connects the rigid part 105a and the rigid part 105b, and the flexible part 105e connects the rigid part 105b and the rigid part 105c.

  The imaging element 100 is mounted on the rigid portion 105a, the imaging IC 101 is mounted on the rigid portion 105b, and the inter-board connector 106 is mounted on the rigid portion 105c. The board-to-board connector 106 is connected to the board-to-board connector 108 of the main wiring board 107 (see FIGS. 10 and 11) on which the video engine is mounted to exchange data.

  When assembling the imaging device 100 to the rigid portion 105a, it is necessary to adjust the tilt so that the light receiving surface of the imaging device 100 is perpendicular to the optical axis at the focal position of the imaging optical system. The tilt adjustment is performed using the sensor plate 103. The sensor plate 103 is biased with respect to the back surface of the lens barrel 102 by springs 110a, 110b, and 110c in a direction away from the back surface of the lens barrel 102. The springs 110 a, 110 b, and 110 c are arranged corresponding to the three screw holes of the sensor plate 103. The tilt adjustment is performed by adjusting the tightening amount when the screws 111a, 111b, and 111c inserted from the screw holes are inserted into the springs 110a, 110b, and 110c and tightened to the lens barrel 102.

  When tilt adjustment is performed on the image sensor 100, the rigid portion 105a moves, but this movement is absorbed by deformation of the flexible portion 105d. The length of the flexible portion 105d is adjusted so that the substrate does not stretch even when the rigid portion 105a moves. Further, in the rigid portion 105c on which the board-to-board connector 106 is mounted, mounting misalignment occurs between the receptacle side (board-to-board connector 108 side) and the plug side (board-to-board connector 106 side) of the board-to-board connector. The mounting deviation at this time is absorbed by the deformation of the flexible portion 105e.

  Further, the lens barrel 102 is provided with a heat radiating plate 104 for releasing the heat of the imaging IC 101, and an elastic heat conduction sheet 109 affixed on the imaging IC 101 and the heat radiating plate 104 of the imaging IC 101. Heat is dissipated.

  On the other hand, there has been proposed a technique for releasing heat from an image sensor by pressing a heat conductive rubber attached to the back surface of the image sensor mounted on a substrate against a holding member of a display unit (Patent Document 1).

  In addition, the heat generated by the image pickup device and the circuit component disposed on the front surface side and the back surface side of the substrate is transmitted through a plurality of heat conductive members interposed between the circuit component and the exterior cover on the back surface side. A technique for radiating heat from the exterior cover to the outside has been proposed (Patent Document 2).

JP 2003-204457 A JP 2005-252547 A

  By the way, in the heat dissipation structure shown in FIGS. 9 to 11, when the substrate of the rigid portion 105a is largely moved by the tilt adjustment of the imaging element 100 described above, the substrate of the rigid portion 105b is also greatly bent through the flexible portion 105d. For this reason, when the heat conductive sheet 109 is not in sufficient contact with the heat radiating plate 104, or conversely, the charge amount (usually about 0.1 mm) of the heat conductive sheet 109 becomes too large and places a large load on the imaging IC 101. May end up.

  Similarly, in the rigid portion 105c on which the board-to-board connector 106 is mounted, if there is a large mounting deviation between the plug side (board-to-board connector 106 side) and the receptacle side (board-to-board connector 108 side), Cannot be absorbed by the flexible portion 105e. For this reason, there is a possibility that the substrate of the rigid portion 105b also moves greatly, the contact between the heat sink 104 and the imaging IC 101 becomes insufficient, and the heat of the imaging IC 101 cannot be released.

  In addition, since the imaging IC 101 becomes very high temperature, the rigid-flex wiring board 105 is easily stretched and bent due to heat, the contact between the heat sink 104 and the imaging IC 101 becomes unstable, and the heat of the imaging IC 101 is stabilized. It becomes difficult to dissipate heat.

  On the other hand, in Patent Document 1 and Patent Document 2, even if the heat of the image sensor or circuit component mounted on the substrate can be efficiently radiated, the substrate moves like the rigid flexible wiring substrate 105 described above. In this case, the contact between the circuit component and the heat sink becomes insufficient.

  Therefore, an object of the present invention is to provide an imaging apparatus that can ensure excellent heat dissipation capability even when a wiring board on which a heat generating circuit component is mounted moves.

  In order to achieve the above object, an image pickup apparatus according to the present invention has a wiring board on which a plurality of circuit components including an image pickup element are mounted and the mounting portions of adjacent circuit components are connected by a flexible portion having flexibility. And heat dissipation for fixing the wiring board by sandwiching the back surface of the mounting part of the circuit component adjacent to the mounting part of the image pickup device and the surface of the circuit component through elastic heat conducting members, respectively, on the wiring board And a board.

  According to the present invention, it is possible to ensure an excellent heat dissipation capability even when a wiring board on which a heat generating circuit component is mounted moves.

It is the disassembled perspective view which looked at the digital camera which is 1st Embodiment of the imaging device of this invention from the front. It is the disassembled perspective view which looked at the digital camera shown in FIG. 1 from the back. It is the sectional view on the AA line of FIG. It is a perspective view of a rigid flexible wiring board. It is a disassembled perspective view for demonstrating the thermal radiation structure of a rigid flexible wiring board. It is a perspective view which shows the relationship between the heat sink at the time of an assembly | attachment, and a rigid flexible wiring board. It is a perspective view which shows an example of the flexible wiring board used with the digital camera which is 2nd Embodiment of the imaging device of this invention. It is principal part sectional drawing of a digital camera. It is a perspective view which shows the rigid flexible wiring board used for the conventional digital camera. It is a disassembled perspective view of the conventional digital camera. It is the BB sectional view taken on the line of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is an exploded perspective view of a digital camera which is a first embodiment of an imaging apparatus according to the present invention as seen from the front, and FIG. 2 is an exploded perspective view of the digital camera shown in FIG.

  In the digital camera of this embodiment, as shown in FIGS. 1 and 2, a lens barrel 3, a metal chassis 4, and a liquid crystal panel 40 that hold a photographing lens and the like are disposed between a front cover 1 and a back cover 2. The A barrel 3, a battery case 5 that holds a battery 15, and a main wiring board 6 are fixed to the metal chassis 4 via screws or the like.

  The main wiring board 6 is mounted with a CPU, a memory, a lens barrel driver circuit, a power supply circuit, a slot of a memory card 7 for storing video and audio, an HDMI connector 8 and the like. By opening and closing the battery lid 21, the battery 15 and the memory card 7 are inserted and removed from the battery case 5 and the slot. Further, the upper wiring board 9 is connected to the main wiring board 6 by a connector.

  A power connector 10 is mounted on the upper surface flexible wiring board 9, and power is sent to the power circuit block on the main wiring substrate 6 through the upper surface flexible wiring substrate 9. A release switch 11, a power switch 12, and an AF auxiliary light LED 13 are mounted on the upper surface flexible wiring board.

  A front radiator plate 14 is disposed on the front surface of the battery case 5. The front heat sink 14 serves to release the heat of the power supply IC to the front side of the camera via a heat conduction sheet (not shown) attached on the power supply IC of the power supply circuit block mounted on the front side of the main wiring board 6. ing.

  An upper surface cover 16 is disposed on the upper surface of the battery case 5 with the upper surface flexible wiring board 9 interposed therebetween. The top cover 16 holds a zoom lever 17, a release button 18, a power button 19, and a mode dial 20. By rotating the mode dial 20, it is possible to switch shooting modes in accordance with shooting scenes such as an auto mode, a portrait mode, and a sports mode.

  A strobe unit 22, a pop-up strobe light emitting unit 23, and a main capacitor 24 are arranged on the side of the lens barrel 3, and a strobe wiring board 25 on which a strobe circuit is mounted is fixed on the back side of the main capacitor 24. Yes. The strobe wiring board 25 is connected to a speaker 26 via a cable. The strobe unit 22 is disposed above the ultrasonic motor 27 assembled to the lens barrel 3 and is fixed to the lens barrel 3 with screws or the like. The side surface of the strobe unit 22 is covered with a side surface cover 39. In addition, microphones 28 and 29 are arranged on both sides of the lens barrel 3 to enable stereo sound recording during moving image shooting.

  On the side of the liquid crystal panel 40, a back operation flexible wiring board 30 is disposed. A plurality of operation members such as a reproduction button 31 and a rotation operation module 32 for switching to the reproduction mode are arranged on the back surface operation flexible wiring board 30. The rotation operation module 32 has functions of both a cross key and a rotation operation, and is fixed to the metal chassis 4 together with the rear operation flexible wiring board 30.

  A jack wiring board 33 on which a USB connector 34 is mounted is disposed between the upper surface flexible wiring board 9 and the upper surface cover 16. The jack wiring board 33 is disposed so that the USB connector 34 is fitted into the recess 5 a provided in the battery case 5, and is fixed to the battery case 5 with screws or the like. Further, the side cover 35 is provided with a recess (not shown) that houses a jack cover 36 for covering the USB connector 34 and the HDMI connector 8. The side cover 35 covers the side surface of the camera and is fixed to the metal chassis 4 together with the strap ring 37 through which the strap string is passed. A rigid flexible wiring board 43 is disposed on the back side of the lens barrel 3.

  Next, an example of the rigid flexible wiring board 43 will be described with reference to FIGS. 3 is a cross-sectional view taken along the line AA of FIG. 2, FIG. 4 is a perspective view of the rigid flexible wiring board 43, FIG. 5 is an exploded perspective view for explaining the heat dissipation structure of the rigid flexible wiring board 43, and FIG. FIG. 6 is a perspective view showing the relationship between the heat sinks 50 and 52 and the rigid flexible wiring board 43.

  As shown in FIGS. 3 to 6, the rigid flexible wiring board 43 includes rigid portions 43 a, 43 b, 43 c and flexible portions 43 d, 43 e having flexibility. The flexible part 43d connects the rigid part 43a and the rigid part 43b, and the flexible part 43e connects the rigid part 43b and the rigid part 43c. An imaging device 44 is mounted on the rigid portion 43a, an imaging IC 45 is mounted on the rigid portion 43b adjacent to the imaging device 44, and an inter-board connector 46 is mounted on the rigid portion 43c adjacent to the imaging IC 45. Is done. The board-to-board connector 46 is connected to the board-to-board connector 47 of the main wiring board 6 on which the video engine is mounted to exchange data.

  The imaging IC 45 includes an imaging signal processing unit, an A / D conversion unit, an image signal processing unit, and the like. The imaging signal processing unit performs imaging signal processing such as correlated double sampling processing for removing a clock of an electrical signal output from the imaging device 44 and reducing noise, and clamping processing for clamping to a predetermined reference voltage. The A / D conversion unit converts the clamp output signal output from the imaging signal processing unit from an analog signal to a digital signal. The image signal processing unit performs various signal processing and conversion so that the digital data sent from the A / D conversion unit is in a format for displaying or recording.

  The layer structure of the rigid flexible wiring board 43 is such that the rigid portions 43a, 43b, and 43c are six layers, and the flexible portions 43d and 43e are two layers. Signals between the rigid parts are exchanged from the third and fourth layers through the flexible part. By using the rigid-flex wiring board 43 and wiring to the imaging IC 45 in the shortest without using a connector, it is possible to prevent noise from being mixed into the analog signal obtained by the imaging element 44.

  The flexible portion 43d is provided for adjustment so that the light receiving surface of the image pickup device 44 is perpendicular to the optical axis at the focal position of the image pickup optical system. The flexible portion 43e is provided to absorb the mounting displacement between the receptacle-side board-to-board connector 47 and the plug-side board-to-board connector 46, and to facilitate the connection of the connectors 46 and 47 during assembly. In the present embodiment, the circuit components on the rigid flexible wiring board 43 are mounted only on one side, and the thickness of the digital camera can be reduced compared to the case where the circuit components are mounted on both sides.

  A sensor plate 48 is attached to the image sensor 44. The heat of the imaging element 44 is conducted to the sensor plate 48, and the heat conducted to the sensor plate 48 is conducted to the sensor side heat radiating plate 50 through the heat conduction sheet 49 having elasticity. The heat sink 50 is disposed on the strobe unit 22 side. As a result, the heat of the image sensor 44 is conducted to the opposite side of the main wiring board 6 and the rigid flexible wiring board 43, and the heat is concentrated on the main wiring board 6 side, and the camera grip is heated. Can be prevented. Further, by dissipating the heat conducted to the heat radiating plate 50 to the front cover 1 and the back cover 2, the heat can be efficiently radiated from the exterior surface, so that the heat radiating effect can be enhanced.

  Between the sensor plate 48 and the back surface of the lens barrel 3, springs 54 a, 54 b, 54 c that urge the sensor plate 48 away from the back surface of the lens barrel 3 are provided in three screw holes provided in the sensor plate 48. Correspondingly arranged. By adjusting the amount of tightening when the screws 55a, 55b, and 55c inserted into the three screw holes of the sensor plate 48 are inserted into the springs 54a, 54b, and 54c and tightened to the back surface of the barrel 3, Aori adjustment is performed. When the tilt adjustment is performed on the image sensor 44, the rigid portion 43a moves. The movement at this time is absorbed by the deformation of the flexible portion 43d.

  The imaging IC 45 mounted on the rigid 43b is attached with an imaging IC thermal conduction sheet 51 having substantially the same shape as the imaging IC 45. The imaging IC thermal conduction sheet 51 is attached to the lens barrel 3 and attached to the strobe unit 22. A heat sink 52 for imaging IC extending to the side is in contact. The imaging IC heat conduction sheet 51 corresponds to an example of the heat conduction member of the present invention. The heat generated in the imaging IC 45 of the rigid portion 43 b is conducted to the imaging IC heat radiating plate 52 through the imaging IC thermal conductive sheet 51.

  At this time, since the imaging IC heat dissipation plate 52 extends to the strobe unit 22 side, the heat of the imaging IC 45 is conducted to the opposite side of the main wiring board 6, thereby concentrating the heat on the main wiring board 6 side. This prevents the camera grip from becoming hot. Further, by dissipating heat conducted to the heat radiating plate 52 to the front cover 1 and the back cover 2, heat can be efficiently radiated from the exterior surface, so that a heat radiating effect can be enhanced.

  The heat radiation sheet 53 for the back surface of the imaging IC is attached to the back surface of the rigid portion 43b on which the imaging IC 45 is mounted. The heat radiation sheet 53 for the back surface of the imaging IC corresponds to an example of the heat conduction member of the present invention. Since the rigid part 43b easily heats the substrate due to the heat generated in the imaging IC 45 and peripheral circuit components, the heat generated in the rigid part 43b is radiated to the metal chassis 4 via the imaging IC backside heat radiation sheet 53. It has a structure to do. In this case, the metal chassis 4 serves as a heat sink.

  In this embodiment, a ground pattern (GND pattern) is wired on the back surface of the rigid portion 43b on which the imaging IC 45 is mounted in order to enhance the heat dissipation effect. In the GND pattern, a through hole that connects each layer of the substrate of the rigid portion 43b and is grounded to the imaging IC 45 is disposed. Thereby, the heat of the mounting surface of the imaging IC 45 is conducted to the back surface of the rigid portion 43b through the through hole, and the heat dissipation efficiency to the metal chassis 4 can be enhanced. Furthermore, the heat radiation efficiency can be further improved by eliminating the resist printing formed on the surface of the GND pattern wired on the back surface of the rigid portion 43b and exposing the GND pattern.

  Here, the rigid portion 43a is moved by the tilt adjustment described above, and the rigid portion 43c is moved by the mounting displacement of the inter-board connectors 46 and 47 described above. For this reason, in this embodiment, the positioning and screwing of the rigid portion 43b are not performed, and the imaging IC heat dissipation plate 52 and the metal chassis 4 are used to rigidly connect the imaging IC heat conduction sheet 51 and the imaging IC rear surface heat dissipation sheet 53. It fixes so that the part 43b may be pinched | interposed.

  Thereby, even when the movement amount of the rigid portion 43a and the rigid portion 43c is large, the imaging IC heat conduction sheet 51 and the imaging IC rear surface heat radiation sheet 53 follow the elasticity of the imaging IC heat radiation plate 52 and the metal. Contact the chassis 4 securely. In addition, the thermal conductivity sheet 51 for the imaging IC is smaller than the thermal modulus of the heat radiation sheet 53 for the back surface of the imaging IC to make it easier to deform, so that the thermal conduction sheet 51 for the imaging IC flexibly contacts the imaging IC 45. As a result, the followability is improved even for parts with irregularities. Furthermore, since the heat dissipation sheet 53 for the back surface of the imaging IC is directly attached to the substrate, the elastic modulus is relatively large, but heat can be efficiently released to the metal chassis 4 by using a material having high thermal conductivity.

  As described above, in the present embodiment, the imaging IC heat conduction sheet 51 and the imaging IC backside heat radiation sheet 53 follow the elasticity of the imaging IC even when the movements of the rigid portions 43a and 43c are large. The heat radiating plate 52 and the metal chassis 4 are securely contacted. As a result, heat generated by the imaging IC 45 mounted on the rigid portion 43b and peripheral circuit components can be efficiently released to the imaging IC heat dissipation plate 52 and the metal chassis 4, and excellent heat dissipation capability can be ensured. .

  Further, even when the digital camera receives an impact due to vibration or dropping, the impact resistance is improved because the imaging IC heat conduction sheet 51 and the imaging IC backside heat dissipation sheet 53 absorb the impact. .

  Furthermore, even when the substrate of the rigid portion 43b, the heat sink 52 for the imaging IC, and the metal chassis 4 are thermally expanded due to heat generated during the photographing operation of the digital camera, the displacement due to the thermal expansion is elastically deformed of the sheets 51 and 53. Can be absorbed.

(Second Embodiment)
Next, a digital camera that is a second embodiment of the imaging apparatus of the present invention will be described with reference to FIGS. FIG. 7 is a perspective view showing an example of a flexible wiring board used in the digital camera of the present embodiment, and FIG. 8 is a cross-sectional view of the main part of the digital camera. In addition, about the part which overlaps or corresponds to the said 1st Embodiment, the same code | symbol is attached | subjected to each figure and the description is abbreviate | omitted.

  In the present embodiment, as shown in FIG. 7, a flexible wiring board 56 is used as a wiring board, and an imaging element 44, an imaging IC 45, and an inter-board connector 46 are provided on the flexible wiring board 56 as in the first embodiment. Has been implemented. Here, the portion of the flexible wiring board 56 between the imaging element 44 and the imaging IC 45 and the portion between the imaging IC 45 and the inter-board connector 46 correspond to an example of the flexible portion of the present invention.

  A reinforcing plate 57 is affixed to the back of the mounting portion of the inter-board connector 46 of the flexible wiring board 56 so that the connector can be easily inserted and removed even in the case of the relatively thin and soft flexible wiring board 56. It has become. In addition, a reinforcing plate may be attached to the back surface of the mounting portion of the imaging element 44 and the back surface of the mounting portion of the imaging IC 45 of the flexible wiring board 56 in order to improve mountability.

  The flexible wiring board 56 is usually covered with a cover lay film made of polyimide. However, the cover lay film has a large opening accuracy and a large misalignment, so that a component with a narrow pitch cannot be mounted. Therefore, in this embodiment, instead of the cover lay film, resist printing 58 (shaded area) is applied to the mounting surface of the imaging IC 45 to enable mounting of components having narrow pitch terminals and high-density mounting.

  As shown in FIG. 8, a heat conduction sheet 59 having substantially the same shape as the image pickup IC 45 is attached to the image pickup IC 45, and a heat conduction sheet 60 is attached to the back surface of the mounting portion of the image pickup IC 45 of the flexible wiring board 56. It has been. In the same manner as in the first embodiment, the imaging IC heat dissipation plate 52 and the metal chassis 4 are fixed so as to sandwich the mounting portion of the imaging IC 45 of the flexible wiring board 56 via the heat conductive sheets 59 and 60. .

  As a result, even when the amount of movement of the mounting portion of the imaging element 44 and the mounting portion of the inter-board connector 46 of the flexible wiring board 56 is large, the heat conductive sheets 59 and 60 follow the elasticity and follow the heat sink 52 for the imaging IC. And it contacts the metal chassis 4 securely. As a result, the heat generated in the imaging IC 45 and peripheral circuits mounted on the flexible wiring board 56 can be efficiently released to the imaging IC heat dissipation plate 52 and the metal chassis 4, and excellent heat dissipation capability can be ensured. Other configurations and operational effects are the same as those of the first embodiment.

  The configuration of the present invention is not limited to those exemplified in the above embodiments, and the material, shape, dimensions, form, number, arrangement location, and the like are appropriately changed without departing from the gist of the present invention. Is possible.

4 Metal Chassis 43 Rigid Flexible Wiring Board 43a Rigid Part 43b Rigid Part 43c Rigid Part 43d Flexible Part 43e Flexible Part 51 Imaging IC Thermal Conductive Sheet 52 Imaging IC Radiation Plate 53 Imaging IC Backside Radiation Sheet

Claims (5)

A plurality of circuit components including an image sensor are mounted, and a wiring board in which the mounting portions of adjacent circuit components are connected by a flexible portion having flexibility,
A heat radiating plate for fixing the wiring board by sandwiching the back surface of the mounting part of the circuit component adjacent to the mounting part of the imaging element and the surface of the circuit component on the wiring board via elastic heat conducting members, respectively. An imaging apparatus comprising:   The elastic modulus of the heat conducting member arranged on the back surface of the circuit component mounting portion on the wiring board is made larger than the elastic modulus of the heat conducting member arranged on the surface of the circuit component. The imaging device according to claim 1.   The imaging device according to claim 1, wherein the wiring board includes a mounting portion for an inter-board connector connected to the mounting portion for the circuit component via the flexible portion.   4. The ground pattern in which a through hole connected to the ground of the circuit component is wired on the back surface of the circuit component mounting portion on the wiring board. The imaging device according to claim 1.   The imaging device according to claim 4, wherein the ground pattern is exposed.

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