Imaging device

Abstract

To provide an imaging apparatus capable of efficiently releasing heat generated by an imaging element while maintaining a wiring from the imaging element.SOLUTION: An imaging apparatus (100) includes an imaging substrate (115a) on which an imaging element (115) is mounted, imaging flexible cables (111, 112) on which a wiring is provided to drive the imaging element, a heat sink (122) for dissipating heat of the imaging element, and heat conductive members (120a, 120b, 121a, 121b). The imaging substrate and the imaging flexible cables are connected to each other via connecting parts (111a, 112a, 115e, 115f). The connecting parts are arranged between the imaging substrate and the heat sink. The heat conductive members are arranged between the imaging substrate and the imaging flexible cables and between the imaging flexible cables and the heat sink.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a heat dissipation structure for an imaging device. [Background technology]

[0002] Imaging devices such as digital cameras are equipped with an imaging element for converting a subject image captured through an imaging lens into a digital image. When the imaging element is driven, heat is generated. The amount of heat generated can cause noise in the image, potentially resulting in a deterioration in image quality. Therefore, it is necessary to ensure good heat dissipation for the heat generated by the imaging element. In particular, imaging devices that frequently take continuous shots or are capable of video recording require high heat dissipation capabilities because a large amount of heat is generated in the imaging element in a short period of time.

[0003] In recent years, imaging devices that optically correct subject blur by moving the image sensor in a direction perpendicular to the optical axis to improve image quality have become popular. Even in imaging devices that perform image blur correction, sufficient heat dissipation is required because heat generated by the image sensor when the image blur correction mechanism is operating affects image quality.

[0004] Patent Document 1 discloses an imaging device that takes heat dissipation into consideration, in which a heat conductive member is arranged on the back surface of an element unit that has an imaging element. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-80059 Summary of the Invention [Problem to be solved by the invention]

[0006] In the prior art disclosed in Patent Document 1, a heat-conducting member is provided with an uneven shape formed in accordance with the uneven shape of electronic components such as an imaging element arranged on a substrate. In recent years, the number of signal lines and power supply wiring drawn from the imaging element has increased due to increases in the power consumption and number of pixels of the imaging element, and the imaging element is connected to the control substrate using a flexible wiring board or cable.

[0007] However, Patent Document 1 does not take into consideration the drawing out of the wiring.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an imaging device that can efficiently release heat generated by an imaging element while maintaining wiring from the imaging element. [Means for solving the problem]

[0009] A control device according to one aspect of the present invention includes an imaging board on which an imaging element is mounted, an imaging flex provided with wiring for driving the imaging element, a heat sink for dissipating heat from the imaging element, and a heat conductive member, wherein the imaging board and the imaging flex are connected via a connection portion, the connection portion being disposed between the imaging board and the heat sink, and the heat conductive member being disposed between the imaging board and the heat sink, and including an area in contact with the imaging board and the heat sink, and areas being disposed between the imaging board and the imaging flex and between the imaging flex and the heat sink, and in contact with the imaging board, the imaging flex, and the heat sink, The hardness of the heat conductive member is lower than the hardness of the imaging substrate and the hardness of the elements mounted on the imaging substrate. It is characterized by:

[0010] Other objects and features of the present invention will be described in the following embodiments. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide an imaging device that can efficiently release heat generated in an imaging element while maintaining wiring from the imaging element. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is an exploded rear perspective view of the digital camera 100. [Figure 2] 1A and 1B are exploded perspective views of an image pickup element unit 106 according to a first embodiment of the present invention; [Figure 3] 1A is a rear view of an image pickup element unit 106 according to a first embodiment, FIG. 1B is a cross-sectional view taken along line AA, FIG. 1C is a cross-sectional view taken along line BB, and FIG. 1D is a cross-sectional view taken along line CC. [Figure 4] 10A and 10B are diagrams showing modified examples of the method for dissipating heat from the movable part 114. FIG. [Figure 5] 10A and 10B are exploded perspective views of an image pickup element unit 106 according to a second embodiment of the present invention; [Figure 6] 10A is a rear view of an image pickup element unit 106 according to a second embodiment, and FIG. 10B is a DD cross-sectional view thereof. [Figure 7] FIG. 10 is a cross-sectional view of an image pickup element unit 106 according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, imaging devices according to the respective embodiments will be described with reference to the accompanying drawings. [Example]

[0014] Fig. 1 is an exploded perspective view of a digital camera 100, which is an imaging device according to Example 1, viewed from the rear side. As shown in Fig. 1, the exterior cover of the digital camera 100 is composed of a rear cover 101, a front base 102, a top cover 103, a bottom cover 104, and a side cover 105. Inside the digital camera 100, an image sensor unit 106 having an image stabilization mechanism, a main board 107, a shutter 108, a viewfinder 109, and a chassis 110 are arranged.

[0015] The imaging element unit 106 is composed of a fixed portion and a movable portion including the imaging element 115. The front base 102 is made of, for example, magnesium die-cast or resin. The main board 107 is composed of a multi-layer board, with electronic components mounted on both sides. The main board 107 is fixed to the front base 102 and a metal chassis 110 with screws. The main board 107 is equipped with a control IC 107a that controls imaging signals, etc., a recording medium connector 107b that accommodates an external recording medium, and an external communication terminal 107c for connecting a connection cable to an external device. The external communication terminal 107c is covered with a sub-cover 105a.

[0016] The image sensor unit 106 is a component of the digital camera 100 that consumes particularly large amounts of power, generates a large amount of heat, and experiences rapid temperature increases. The shooting time of the digital camera 100 is limited by the guaranteed operating temperatures of each component. In order to maintain the longest possible shooting time, it is necessary to take measures to dissipate heat from the image sensor unit 106, which is a heat source, so that the guaranteed operating temperatures are not exceeded. The image sensor unit 106 is fixed to the front base 102 with screws, so the heat from the image sensor unit 106 is dissipated to the front base 102.

[0017] The image sensor unit 106 will be described in detail with reference to Figures 2 and 3. Figure 2(a) is an exploded perspective view of the image sensor unit 106 as seen from the front side. Figure 2(b) is an exploded perspective view of the image sensor unit 106 as seen from the rear side. Figure 3(a) is a rear view of the image sensor unit 106, excluding the fixed portion 113. Figure 3(b) is a cross-sectional view of the image sensor unit 106 taken along line AA in Figure 3(a). Figure 3(c) is a cross-sectional view of the image sensor unit 106 taken along line BB in Figure 3(a). Figure 3(d) is a cross-sectional view of the image sensor unit 106 taken along line CC in Figure 3(a).

[0018] The movable part 114 has a coil part 116 in which a coil and a Hall element for operating the image sensor 115 are arranged, and is held by a sensor holder 117. Three magnets 118 are held by the fixed part 113. The movable part 114 is attracted and held by the magnets 118. A ball (not shown) is placed in a ball holding part 117a provided on the sensor holder 117 between the movable part 114 and the fixed part 113. The movable part 114 can be moved by changing the amount of current flowing through the coil part 116. Image stabilization can be performed by moving the movable part 114 in a direction that cancels out shake of the digital camera 100 body.

[0019] A sensor chip 115b is attached to an imaging substrate 115a on which an imaging circuit is mounted, and the sensor chip 115b is electrically connected to the imaging substrate 115a by wire bonding. A sensor frame 115c is formed on the imaging substrate 115a, and the sensor chip 115b is sealed with glass 115d. The imaging element 115 and sensor holder 117 are bonded and fixed with adhesive 119. The adhesive 119 is applied so as to straddle the imaging substrate 115a and the sensor holder 117, and is hardened by irradiating it with ultraviolet light. Elements 126 such as capacitors, resistors, and regulators of the imaging circuit are mounted on the imaging substrate 115a. The elements 126 are mounted on the surface (back surface) of the imaging substrate 115a opposite to the surface on which the sensor chip 115b is attached.

[0020] The imaging element unit 106 and the main board 107 are electrically connected using a flexible wiring board. An imaging signal flex 111 sends imaging signals output from the imaging element 115 and control signals required to drive the imaging element 115 to a control IC 107a on the main board 107. An imaging power supply flex 112 supplies power to drive the imaging element 115.

[0021] An inter-board connector is used as a connection between the imaging board 115a and each of the imaging flex 111, 112 (hereinafter simply referred to as flex). Receptacles 111a and 112a of the inter-board connector are mounted on the flex side, and plugs 115e and 115f of the inter-board connector are mounted on the imaging board 115a side. The inter-board connector receptacles 111a, 112a and the plugs 115e, 115f are fitted together to establish an electrical connection. Reinforcing plates 111b, 112b are attached to the surface (back surface) of the flex opposite to the surface on which the inter-board connector receptacles 111a, 112a are mounted, so as to overlap the receptacles 111a, 112a. The reinforcing plates 111b, 112b are made of metal such as aluminum or stainless steel, glass epoxy resin, or the like. This has the effect of reducing stress on the solder where the inter-board connector is mounted when connecting or disconnecting the inter-board connector, and keeping the flexible cable flat when mounting the inter-board connector. Similarly, for connection between the main board 107 and the flexible cable, the flexible cable is connected to a connector 107d for the imaging signal flexible cable 111 and a connector 107e for the imaging power supply flexible cable 112 mounted on the main board 107. The flexible cables are attached to attachment portions 113a of the fixing portion 113 with double-sided tapes 111c and 112c, respectively.

[0022] The flexible cable has U-turn portions 111d and 112d, which are formed by making a U-turn on the flexible cable between the attachment portion 113a and the inter-board connector on the imaging board 115a. These U-turn portions 111d and 112d absorb misalignment when the imaging element 115 moves, preventing the flexible cable from interfering with the movement of the movable portion 114. They also suppress breakage of the wiring within the flexible cable. The imaging signal flexible cable 111 and the imaging power supply flexible cable 112 are single-sided flexible cables. Single-sided flexible cables can reduce the amount of copper foil and coverlay compared to double-sided flexible cables, thereby reducing the stiffness of the flexible cable. This reduces the load when the movable portion 114 is moved and also increases the durability of the flexible cable when it is repeatedly bent.

[0023] 3(c) shows a BB cross-sectional view of the inter-board connector portion of the imaging signal flexible cable 111. FIG. 3(d) shows a CC cross-sectional view of the inter-board connector portion of the imaging power supply flexible cable 112.

[0024] Board-side thermally conductive members 120a and 121a are disposed on the imaging board 115a. The board-side thermally conductive members 120a and 121a are shaped to avoid the plugs 115e and 115f of the board-to-board connectors, respectively. The board-side thermally conductive members 120a and 121a are made of low-hardness silicone rubber or putty-like material. The board-side thermally conductive members 120a and 121a have lower hardness than the imaging board 115a, the element 126 mounted on the imaging board 115a, the reinforcing plate, and the like. By pressing the board-side thermally conductive members 120a and 121a, the board-side thermally conductive members 120a and 121a conform to the shape of the element 126 on the imaging board 115a. As a result, the board-side thermally conductive members 120a and 121a come into close contact with the surface of the imaging board 115a and the element 126. The thickness of the board-side heat conduction members 120a, 121a is adjusted to approximately match the height of the receptacles 111a, 112a of the board-to-board connector mounted on the flex cable. The imaging signal flex cable 111 and the imaging power flex cable 112 are arranged at different heights when the board-to-board connector is mated so that the flex cables do not interfere with each other when the board-to-board connector is connected. Therefore, the board-side heat conduction members 120a, 121a also have different thicknesses. When the board-to-board connector is connected in this state, the flex cable and the board-side heat conduction members 120a, 121a can be tightly attached. Further, heat sink side heat conduction members 120b, 121b are arranged on the flex cable. The heat sink side heat conduction members 120b, 121b are in tight contact with the heat sink 122. The heat sink side heat conduction members 120b, 121b also have a thickness that matches the gap between the flex cable and the heat sink 122.

[0025] Even if there is an excess of substrate-side heat conduction members 120a, 121a or heat sink-side heat conduction members 120b, 121b, spaces 123 are provided around heat conduction members 120a, 121a, 120b, 121b to allow the heat conduction members to escape. This allows the heat conduction members 120a, 121a, 120b, 121b to escape to the outside even if there is an excess of heat conduction members 120a, 121a, 120b, 121b supplied, thereby reducing the load on image sensor 115.

[0026] Heat sink 122 is fixed to sensor holder 117 with three screws 124. A graphite sheet 125 is attached to heat sink 122. Like the flexible cable, graphite sheet 125 has adhesive surface 125a attached to attachment portion 113a of fixed portion 113. Graphite sheet 125 also has a U-turn portion so as not to interfere with the movement of movable portion 114.

[0027] Next, heat dissipation from the image sensor 115 will be described. The image sensor 115 mainly generates heat from the sensor chip 115b. First, the heat dissipation path from the adhesive 119, which is the substrate bonding part, will be described. The image sensor 115 and the sensor holder 117 are bonded with the adhesive 119. As a result, heat from the image sensor 115 is transferred to the sensor holder 117. A heat sink 122 is fixed to the sensor holder 117 with screws, and the heat transferred to the sensor holder 117 is transferred to the heat sink 122. The heat transferred to the heat sink 122 then travels through the graphite sheet 125 to the fixed part 113. The heat is then transferred to the front base 102, to which the fixed part 113 is fixed with screws, and is released from the exterior cover of the digital camera 100.

[0028] Next, the heat dissipation path from the thermal conduction members 120a, 121a, 120b, and 121b will be described. Heat from the imaging element 115 is conducted to the board-side thermal conduction members 120a and 121a attached to the imaging board 115a. The board-side thermal conduction members 120a and 121a are in close contact with the imaging signal flexible cable 111 and the imaging power flexible cable 112, respectively. The heat is conducted via the flexible cables to the heat sink-side thermal conduction members 120b and 121b, which are also in close contact with the flexible cables. The heat is then conducted to the heat sink 122. The subsequent heat dissipation path is the same as that from the substrate adhesive portion described above. In this case, it is desirable that the reinforcing plates 111b and 112b of the flexible cables be formed from aluminum or other materials with high thermal conductivity. The thermal conduction members 120a, 121a, 120b, and 121b are arranged to include at least a portion of the projection area of ​​the sensor chip 115b. This allows heat to escape more easily and also reduces temperature differences within the sensor chip 115b that may affect images. Preferably, the thermal conduction members 120a, 121a, 120b, and 121b are positioned on the projection of the sensor chip 115b.

[0029] Normally, when a flexible cable is routed between the imaging board 115a and the heat sink 122, it is necessary to arrange the heat conduction members 120a, 121a, 120b, and 121b so as to avoid the entire flexible cable. By arranging the flexible cable between two heat conduction members, the board-side heat conduction members 120a and 121a and the heat sink-side heat conduction members 120b and 121b, in this way, it is possible to arrange the heat conduction members 120a, 121a, 120b, and 121b over a wide area. This allows for effective heat dissipation from the imaging element 115. In areas where no flexible cable is arranged, a single heat conduction member may be arranged to transfer heat.

[0030] Because heat sink 122 biases reinforcing plates 111b, 112b against the board-to-board connector via heat sink-side thermally conductive members 120b, 121b, it is possible to prevent the board-to-board connector from coming loose due to an impact such as being dropped. In this case, the hardness of board-side thermally conductive members 120a, 121a and the hardness of heat sink-side thermally conductive members 120b, 121b may be made different. By making the hardness of board-side thermally conductive members 120a, 121a lower than the hardness of heat sink-side thermally conductive members 120b, 121b, the repulsive force from board-side thermally conductive members 120a, 121a is reduced, making it possible to make the board-to-board connector less likely to come loose.

[0031] Lead-out portions 111e and 112e, which connect the flex's reinforcing plates 111b and 112b to U-turn portions 111d and 112d, are sandwiched between two heat-conducting members: board-side heat-conducting members 120a and 121a and heat-sink-side heat-conducting members 120b and 121b. Lead-out portions 111e and 112e are locations where stress tends to concentrate when movable portion 114 is repeatedly moved. By sandwiching lead-out portions 111e and 112e between two soft heat-conducting members, stress concentration can be prevented, and breakage of the flex can be reduced.

[0032] In this embodiment, the flexible cable is sandwiched between two heat conducting members, but it may also be configured so that one heat conducting member is wrapped around both sides of the flexible cable to sandwich it.

[0033] 4 is a diagram showing a modified example of a method for dissipating heat from movable part 114. Heat dissipation fins 122a are provided on heat dissipation plate 122. Heat from imaging element 115 is conducted to heat dissipation plate 122 via thermal conduction members 120a, 121a, 120b, and 121b. By blowing air onto fins 122a with a fan or the like, heat can be dissipated more effectively. [Example]

[0034] Next, a second embodiment will be described with reference to FIGS. 5 and 6. In this embodiment, the flexible connection method and the heat conductive member are changed from those of the image sensor unit 106 described in the first embodiment. The other basic configurations are the same as those of the first embodiment. The same reference numerals are used for parts with the same configurations, and detailed descriptions thereof will be omitted. FIGS. 5(a) and 5(b) are exploded perspective views of the image sensor unit 106 in the second embodiment. FIG. 6(a) is a rear view of the image sensor unit 106 in the second embodiment. FIG. 6(b) is a DD cross-sectional view of the image sensor unit 106 in FIG. 6(a).

[0035] The imaging signal flexible cable 200 has a conductor exposed portion 200a. A conductor exposed portion 201b is provided on the imaging board 201a. The imaging board 201a and the flexible cable are connected by overlapping the conductor exposed portion 200a and the conductor exposed portion 201b, placing an ACF (anisotropic conductive film) or solder between them, and thermocompression bonding. A board-side heat conduction member 202 is arranged on the imaging board 201a in a location other than the conductor exposed portion 201b. A heat sink-side heat conduction member 203 is arranged between the heat sink 122 and the imaging signal flexible cable 200. In addition, a connection portion heat conduction member 204 is arranged on the connection portion between the imaging board 201a and the flexible cable. Heat from the imaging element 115 is conducted to the heat sink 122 via the heat conduction members 202, 203, and 204. In the areas where the flexible cable is routed, heat is transferred via the thermal conduction members 202, 203, and 204 and the flexible cable. With this configuration, even if the flexible cable is routed on the imaging board 201a, heat can be transferred efficiently to the heat sink 122. Furthermore, with connection methods using thermocompression bonding, there is a concern that the connection may come off due to pulling. However, because the flexible cable is fixed by sandwiching it between the board-side thermal conduction member 202 and the heat sink-side thermal conduction member 203, stress on the connection can be suppressed even if the movable part 114 moves. Furthermore, because the connection part is also biased by the connection part thermal conduction member 204, it is possible to make the connection part less likely to come off.

[0036] In this embodiment, a flexible wiring board is used as an example, but a thin coaxial cable may be used to connect the main board 107 and the imaging board 201a, and the thin coaxial cable drawn out from the imaging board 201a may be sandwiched on both sides by heat conduction members 202 and 203. [Example]

[0037] Next, a third embodiment will be described with reference to FIG. 7. In this embodiment, the holding method for the image sensor unit 106 described in the first embodiment is changed. FIG. 7 shows a cross-sectional view of the image sensor unit 106. The sensor holder 300 is disposed in front of the image sensor 115. The sensor holder 300 and the image sensor 115 are bonded and fixed with an adhesive 301. The holding member 302 is configured to receive the sensor holder 300 from the front. The holding member 302 is also fixed to the heat sink 122. With this configuration, the repulsive force applied to the image sensor 115 and the adhesive 301 by the thermal conduction members 120a and 120b can be suppressed.

[0038] Although the preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples, and various combinations, modifications, and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0039] Imaging device 100 Image sensor 115 Imaging board 115a Imaging flex 111,112 Heat sink 122 Heat conductive members 120a, 120b, 121a, 121b Connections 111a, 112a, 115e, 115f

Claims

1. an imaging board on which an imaging element is mounted; an imaging flex provided with wiring for driving the imaging element; a heat sink for dissipating heat from the imaging element; a heat conduction member; The imaging board and the imaging flexible cable are connected via a connection portion, the connection portion is disposed between the imaging board and the heat sink, the thermal conduction member is disposed between the imaging board and the heat sink, and includes a region in contact with the imaging board and the heat sink, and regions disposed between the imaging board and the imaging flex and between the imaging flex and the heat sink, and regions in contact with the imaging board, the imaging flex, and the heat sink, The imaging device according to claim 1, wherein the hardness of the thermally conductive member is lower than the hardness of the imaging substrate and the hardness of an element mounted on the imaging substrate.

2. the connection portion that connects the imaging board and the imaging flexible cable is an inter-board connector, the board-to-board connector is mounted on the imaging flexible cable; 2. The imaging device according to claim 1, wherein a reinforcing plate is attached to a surface of the imaging flexible cable opposite to a surface on which the board-to-board connector is mounted, so as to overlap the board-to-board connector.

3. 3. The imaging device according to claim 2, wherein the reinforcing plate is made of metal or glass epoxy resin.

4. 4. The imaging device according to claim 2, wherein the hardness of the heat conductive member is lower than the hardness of the reinforcing plate.

5. 5. The imaging device according to claim 1, wherein the heat conducting member is made of silicone rubber or a putty-like material.

6. 6. The imaging device according to claim 1, wherein a space is provided around the heat conducting member to allow excess heat conducting member to escape.

7. the heat conduction member includes a board-side heat conduction member disposed between the imaging board and the imaging flex, and a heat dissipation plate-side heat conduction member disposed between the imaging flex and the heat dissipation plate, 7. The imaging device according to claim 1, wherein the substrate-side thermal conduction member has a hardness lower than that of the heat sink-side thermal conduction member.

8. the imaging flex includes a drawer portion that is drawn out from the location where the reinforcing plate is attached, 5. The imaging device according to claim 2, wherein the lead-out portion is sandwiched between the heat-conducting members.

9. 9. The imaging device according to claim 1, wherein the heat conducting member is disposed so as to include at least a part of a projection area of ​​a sensor chip of the imaging element.

10. 10. The imaging device according to claim 1, wherein the heat sink is provided with heat dissipation fins.

11. The imaging device described in any one of claims 1 to 10, characterized in that the thermal conduction member is arranged between the imaging board and the heat sink and has an area that is in close contact with the imaging board and the heat sink, and areas that are arranged between the imaging board and the imaging flex and between the imaging flex and the heat sink and are in close contact with the imaging board, the imaging flex, and the heat sink.

Images