JP2023030548A - Imaging apparatus - Google Patents

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

The present invention relates to a heat dissipation structure for an imaging device.

2. Description of the Related Art An imaging device such as a digital camera is provided with an imaging element for converting a subject image captured through an imaging lens into a digital image. Driving the imaging element generates heat. The amount of heat generated may cause noise in the image, resulting in deterioration of the image quality. Therefore, it is necessary to ensure good heat dissipation for the heat generated by the imaging device. In particular, in an imaging device that frequently takes continuous shots or that is capable of capturing moving images, a large amount of heat is generated in an imaging device in a short period of time, so high heat dissipation is required.

Further, in recent years, in order to improve image quality, an imaging apparatus has become popular that optically corrects blurring of a subject by moving an imaging element in a direction orthogonal to the optical axis direction. In imaging apparatuses that perform image blur correction, heat generated in the image sensor affects image quality when the image blur correction mechanism is driven, so sufficient heat dissipation is required.

Japanese Unexamined Patent Application Publication No. 2002-100000 discloses an image pickup apparatus that takes heat dissipation into consideration, in which a thermally conductive member is arranged on the back surface of an element unit having an image pickup element.

JP 2015-80059 A

In the prior art disclosed in Patent Document 1, a heat conduction member is provided that has an uneven shape formed according to the uneven shape of an electronic component such as an imaging device arranged on a substrate. In recent years, due to the increase in power consumption and the number of pixels of image sensors, the number of signal lines and power supply wiring drawn from image sensors has increased, and image sensors are connected to control boards using flexible wiring boards and cables. It is

However, Patent Document 1 does not consider wiring extraction.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an imaging apparatus capable of efficiently releasing heat generated in an imaging element while maintaining wiring from the imaging element.

An imaging device as one aspect of the present invention includes an imaging substrate on which an imaging device is mounted, an imaging flexible board provided with wiring for driving the imaging device, a heat sink for heat dissipation of the imaging device, and a thermally conductive member, wherein the imaging substrate and the imaging flexible board are connected via a connecting portion, the connecting portion is disposed between the imaging substrate and the heat sink, and the thermally conductive member is connected to the imaging substrate. It is characterized by being arranged between a substrate and the imaging flexible board and between the imaging flexible board and the heat sink.

Other objects and features of the invention are described in the following embodiments.

According to the present invention, it is possible to provide an imaging apparatus capable of efficiently releasing heat generated in an imaging element while maintaining wiring from the imaging element.

2 is an exploded rear perspective view of the digital camera 100. FIG. 3A and 3B are a front exploded perspective view and a rear exploded perspective view, respectively, of the imaging element unit 106 of Example 1. FIG. FIG. 4A is a rear view, (b) a sectional view taken along line AA, (c) a sectional view taken along line BB, and (d) a sectional view taken along line CC of the image sensor unit 106 of Example 1. FIG. FIG. 10 is a diagram showing a modification of the method of dissipating heat from the movable portion 114; 8A and 8B are a front exploded perspective view and a rear exploded perspective view of an image sensor unit 106 of Example 2; FIG. FIG. 10A is a rear view and (b) a DD cross-sectional view of an image sensor unit 106 of Example 2. FIG. FIG. 11 is a cross-sectional view of an image sensor unit 106 of Example 3;

An imaging apparatus according to each embodiment will be described below with reference to the accompanying drawings.

FIG. 1 is an exploded perspective view of a digital camera 100, which is an imaging device according to the first embodiment, viewed from the rear side. As shown in FIG. 1, the exterior cover of the digital camera 100 comprises a rear cover 101, a front base 102, a top cover 103, a bottom cover 104 and side covers 105. As shown in FIG. Inside the digital camera 100, an image sensor section 106 having an image blur correction mechanism, a main board 107, a shutter 108, a viewfinder 109, and a chassis 110 are arranged.

The imaging element section 106 is composed of a fixed section and a movable section including the imaging element 115 . The front base 102 is made of magnesium die casting or resin, for example. The main board 107 is composed of a multilayer board, and electronic components are mounted on both sides. The main board 107 is screwed to the front base 102 and the metal chassis 110 . The main substrate 107 is mounted with a control IC 107a for controlling imaging signals and the like, a recording medium connector 107b for accommodating 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 the secondary cover 105a.

The image sensor unit 106 is a member that consumes particularly large power and generates a large amount of heat in the digital camera 100, and the temperature rises rapidly. The photographing time of the digital camera 100 is limited by the guaranteed operating temperature of each member. In order to maintain the shooting time as long as possible, it is necessary to take measures to release the heat of the image sensor unit 106, which is a heat source, so as not to exceed the guaranteed operating temperature. Since the image sensor section 106 is screw-fixed to the front base 102 , the heat of the image sensor section 106 is released to the front base 102 .

The details of the image sensor unit 106 will be described with reference to FIGS. 2 and 3. FIG. FIG. 2(a) is an exploded perspective view of the image sensor unit 106 as seen from the front side. FIG. 2(b) is an exploded perspective view of the imaging device unit 106 as seen from the rear side. FIG. 3A is a rear view of the image sensor section 106. FIG. However, the fixed part 113 is excluded. FIG. 3(b) is a cross-sectional view of the image sensor section 106 taken along the line AA in FIG. 3(a). FIG. 3(c) is a BB cross-sectional view of the image sensor unit 106 in FIG. 3(a). FIG. 3(d) is a CC cross-sectional view of the image sensor unit 106 in FIG. 3(a).

The movable part 114 has a coil part 116 in which a coil and a Hall element for operating the imaging device 115 are arranged, and is held by a sensor holder 117 . The fixed portion 113 holds three magnets 118 . The movable portion 114 is attracted and held by a magnet 118 . Between the movable part 114 and the fixed part 113, a ball (not shown) is put in a ball holding part 117a provided in the sensor holder 117. As shown in FIG. The movable portion 114 can be moved by changing the energization amount of the coil portion 116 . By moving the movable part 114 in the direction of canceling the shake of the main body of the digital camera 100, camera shake correction can be applied.

A sensor chip 115b is adhered 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 the sensor holder 117 are adhered and fixed with an adhesive 119 . The adhesive 119 is applied across the imaging substrate 115a and the sensor holder 117, and cured by irradiation with ultraviolet rays. Elements 126 such as capacitors, resistors, and regulators of the imaging circuit are mounted on the imaging substrate 115a. The element 126 is mounted on the surface (back surface) opposite to the surface of the imaging substrate 115a to which the sensor chip 115b is attached.

The electrical connection between the imaging element section 106 and the main board 107 is performed using a flexible wiring board. An imaging signal output from the imaging device 115 and a control signal necessary for driving the imaging device 115 are sent to the control IC 107 a on the main substrate 107 by the imaging signal flexible circuit 111 . The imaging power flexible 112 supplies power for driving the imaging element 115 .

A board-to-board connector is used as a connecting portion to connect the imaging board 115a and the imaging flexible boards 111 and 112 (hereinafter simply flexible boards). Board-to-board connector receptacles 111a and 112a are mounted on the flexible board side, and board-to-board connector plugs 115e and 115f are mounted on the imaging board 115a side. The receptacles 111a and 112a of the inter-board connector and the plugs 115e and 115f are fitted to establish an electrical connection. On the flexible cable, reinforcing plates 111b and 112b are attached to the surface opposite to the surface on which the receptacles 111a and 112a of the inter-board connector are mounted (back surface) so as to overlap the receptacles 111a and 112a. The reinforcing plates 111b and 112b are made of metal such as aluminum or stainless steel, glass epoxy resin, or the like. This has the effect of reducing the stress on the solder where the board-to-board connector is mounted when connecting or disconnecting the board-to-board connector, and keeping the flexible cable flat when mounting the board-to-board connector. Similarly, the main board 107 and the flexible board are connected to a connector 107d for the imaging signal flexible board 111 and a connector 107e for the imaging power flexible board 112 mounted on the main board 107. FIG. The flexible boards are respectively attached to the attaching portions 113a of the fixed portion 113 with double-sided tapes 111c and 112c.

The flexible board is provided with U-turn portions 111d and 112d formed by U-turning the flexible board between the attachment portion 113a and the board-to-board connector on the imaging board 115a. The U-turn portions 111 d and 112 d can absorb displacement when the imaging element 115 moves, and prevent the flexible cable from interfering with the movement of the movable portion 114 . Also, it is possible to suppress disconnection of the wiring in the flexible cable. The imaging signal flexible 111 and the imaging power flexible 112 are made of single-sided flexible. Compared to double-sided flexible, single-sided flexible can reduce copper foil and coverlay, and can reduce stiffness of flexible. As a result, the load when moving the movable portion 114 can be reduced, and the durability when the flexible cable is repeatedly bent can be improved.

FIG. 3(c) shows a BB cross-sectional view of the board-to-board connector portion of the imaging signal flexible cable 111. As shown in FIG. FIG. 3D shows a CC sectional view of the board-to-board connector portion of the image pickup power flexible cable 112. As shown in FIG.

Substrate-side heat conduction members 120a and 121a are arranged on the imaging substrate 115a. The board-side heat-conducting members 120a and 121a are shaped to avoid the plugs 115e and 115f of the inter-board connectors, respectively. The substrate-side heat-conducting members 120a and 121a are made of low-hardness silicone rubber or putty-like members. The board-side heat-conducting 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 substrate-side thermally conductive members 120a and 121a, the substrate-side thermally conductive members 120a and 121a follow the shape of the element 126 on the imaging substrate 115a. As a result, the board-side heat-conducting members 120a and 121a are brought into close contact with the surface of the imaging board 115a and the element 126. FIG. The thickness of the board-side thermally conductive members 120a and 121a is adjusted so as to substantially match the height of the receptacles 111a and 112a of the board-to-board connector mounted flexibly. The imaging signal flexible cable 111 and the imaging power flexible cable 112 are provided at different heights when the inter-board connector is fitted so that the flexible cables do not interfere with each other when the inter-board connector is connected. Therefore, the board-side thermally conductive members 120a and 121a also have different thicknesses. When the board-to-board connector is connected in this state, the flexible board and the board-side heat conducting members 120a and 121a can be brought into close contact with each other. Radiator-side heat-conducting members 120b and 121b are further arranged on the flexible board. The radiator plate-side heat conduction members 120 b and 121 b are in close contact with the radiator plate 122 . The radiator-plate-side heat-conducting members 120 b and 121 b also have a thickness that matches the gap between the flexible board and the radiator plate 122 .

Spaces 123 are provided around the heat-conducting members 120a, 121a, 120b, 121b to allow the heat-conducting members to escape even if the board-side heat-conducting members 120a, 121a and the radiator plate-side heat-conducting members 120b, 121b are excessive. It is As a result, even if the thermally conductive members 120a, 121a, 120b, and 121b are excessively supplied, the thermally conductive members 120a, 121a, 120b, and 121b can escape to the outside, thereby reducing the load on the imaging element 115. can.

The radiator plate 122 is fixed to the sensor holder 117 with three screws 124 . A graphite sheet 125 is attached to the radiator plate 122 . The graphite sheet 125 is also attached to the attaching portion 113a of the fixing portion 113 with the adhesive surface 125a, similarly to the flexible board. Further, the graphite sheet 125 is also provided with a U-turn portion so that the movement of the movable portion 114 is not hindered.

Next, the heat dissipation of the imaging device 115 will be described. The sensor chip 115b of the imaging device 115 mainly generates heat. First, the heat radiation path from the adhesive 119, which is the substrate bonding portion, will be described. The imaging element 115 and the sensor holder 117 are adhered with an adhesive 119 . Therefore, the heat of the imaging element 115 is transferred to the sensor holder 117 . A radiator plate 122 is screw-fixed to the sensor holder 117 , and the heat transmitted to the sensor holder 117 is transmitted to the radiator plate 122 . The heat transmitted to the heat sink 122 is transmitted through the graphite sheet 125 to the fixed portion 113 side. Then, the heat is transferred to the front base 102 to which the fixed portion 113 is fixed with screws, and the heat is emitted from the external cover of the digital camera 100 .

Next, heat radiation paths from the heat conducting members 120a, 121a, 120b, and 121b will be described. The heat of the imaging device 115 is transferred to the board-side thermal conduction members 120a and 121a attached to the imaging board 115a. The board-side heat-conducting members 120a and 121a are in close contact with the imaging signal flexible cable 111 and the imaging power flexible cable 112, respectively. Likewise, the heat is transferred to the heat-dissipating plate-side heat-conducting members 120b and 121b, which are in close contact with the flexible printed circuit, through the flexible printed circuit. Then, the heat is transferred to the radiator plate 122 . After that, it is the same as the heat radiation path from the substrate bonding portion described above. At this time, it is desirable that the flexible reinforcing plates 111b and 112b are made of aluminum having high thermal conductivity. The thermally conductive members 120a, 121a, 120b, 121b are arranged so as to include at least part of the projected area of the sensor chip 115b. As a result, the heat can be released more easily, and the temperature difference in the sensor chip 115b, which may affect the image, can be reduced. Preferably, the heat conducting members 120a, 121a, 120b, 121b are arranged on the projection of the sensor chip 115b.

Normally, when a flexible cable is routed between the imaging substrate 115a and the heat sink 122, it is necessary to arrange the heat conducting members 120a, 121a, 120b, and 121b while avoiding the entire flexible cable. In this way, by arranging the two heat conducting members, ie, the board side heat conducting members 120a and 121a and the radiator plate side heat conducting members 120b and 121b so as to sandwich the flexible board, the heat conducting members 120a, 121a, 120b and 121b can be spread over a wide range. can be placed. As a result, heat can be effectively dissipated from the imaging device 115 . A single heat-conducting member may be arranged to transfer heat to a portion where the flexible board is not arranged.

Since the radiator plate 122 biases the reinforcing plates 111b and 112b against the board-to-board connector through the heat-radiating plate-side heat conduction members 120b and 121b, it is possible to prevent the board-to-board connector from coming off due to impact such as dropping. can. At this time, the hardness of the board-side heat conduction members 120a and 121a and the hardness of the radiator plate-side heat conduction members 120b and 121b may be different. By making the hardness of the board-side heat-conducting members 120a and 121a lower than the hardness of the heat-dissipating-plate-side heat-conducting members 120b and 121b, the repulsive force from the board-side heat-conducting members 120a and 121a is reduced, and the board-to-board connector is more easily disengaged. can be made difficult.

The lead-out portions 111e and 112e, which are connected to the U-turn portions 111d and 112d from the portions where the reinforcing plates 111b and 112b of the flexible cable are attached, are connected to the board-side heat-conducting members 120a and 121a and the heat-dissipating plate-side heat-conducting members 120b and 121b. sandwiched between two heat-conducting members. The drawn portions 111e and 112e are locations where stress tends to concentrate when the movable portion 114 is repeatedly moved. By sandwiching the lead-out portions 111e and 112e between two soft heat-conducting members, it is possible to prevent the concentration of stress and suppress the breakage of the flexible cable.

In this embodiment, the flexible printed circuit board is sandwiched between two thermally conductive members.

FIG. 4 is a diagram showing a modification of the method of dissipating heat from the movable portion 114. As shown in FIG. The radiator plate 122 is provided with radiator fins 122a. The heat of the imaging element 115 is transmitted to the heat sink 122 via the heat conducting members 120a, 121a, 120b, and 121b. Heat can be released more effectively by blowing air to the fins 122a with a fan or the like.

Next, Example 2 will be described with reference to FIGS. 5 and 6. FIG. In the present embodiment, the connection method of the flexible printed circuit board and the heat-conducting member are changed from those of the image sensor section 106 described in the first embodiment. Other basic configurations are the same as those of the first embodiment. Parts having the same configuration are denoted by the same reference numerals, and detailed description thereof will be omitted. 5(a) and 5(b) are exploded perspective views of the image sensor unit 106 according to the second embodiment. FIG. 6A is a rear view of the image sensor unit 106 in Example 2. FIG. FIG. 6B is a DD cross-sectional view of the image sensor unit 106 in FIG. 6A.

The imaging signal flexible board 200 has an exposed conductor portion 200a. A conductor exposed portion 201b is provided on the imaging substrate 201a. The connection between the imaging board 201a and the flexible board is performed by placing an ACF (anisotropic conductive film) or solder between the exposed conductor portions 200a and 201b in a state of being superimposed, and performing thermocompression bonding. A substrate-side thermally conductive member 202 is arranged on the imaging substrate 201a except for the exposed conductor portion 201b. The radiator plate-side heat conduction member 203 is arranged between the radiator plate 122 and the imaging signal flexible board 200 . Also, the connection portion heat conducting member 204 is arranged on the connection portion between the imaging substrate 201a and the flexible board. Heat from the imaging device 115 is transferred to the heat sink 122 via the heat conducting members 202 , 203 and 204 . Heat is transmitted through the heat-conducting members 202, 203, 204 and the flexible printed circuit at the locations where the flexible printed circuit is laid. By adopting such a configuration, heat can be efficiently transferred to the radiator plate 122 even if the flexible board is laid on the imaging substrate 201a. Moreover, in the connection method using thermocompression, there is a concern that the connection portion may be peeled off due to pulling. However, since the flexible board is sandwiched between the board-side heat-conducting member 202 and the heat-dissipating plate-side heat-conducting member 203 and fixed, even if the movable portion 114 moves, stress applied to the connecting portion can be suppressed. Further, since the connecting portion is also biased by the connecting portion heat conducting member 204, it is possible to make the connecting portion more difficult to come off.

In this embodiment, a flexible wiring board is used as an example, but a thin coaxial cable is used to connect the main board 107 and the imaging board 201a. , 203 may be configured.

Next, Example 3 will be described with reference to FIG. In this embodiment, the holding method is different from that of the image sensor unit 106 described in the first embodiment. FIG. 7 shows a cross-sectional view of the image sensor section 106. As shown in FIG. The sensor holder 300 is arranged in front of the imaging device 115 . The sensor holder 300 and the image pickup device 115 are adhered and fixed with an adhesive 301 . The holding member 302 is configured to receive the sensor holder 300 from the front surface. Also, the holding member 302 is fixed to the heat sink 122 . With such a configuration, the repulsive force applied to the imaging element 115 and the adhesive 301 by the thermally conductive members 120a and 120b can be suppressed.

Although 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.

Imaging device 100
Image sensor 115
Imaging board 115a
Imaging flexible 111, 112
Heat sink 122
Thermally conductive member 120a, 120b, 121a, 121b
Connections 111a, 112a, 115e, 115f

Claims (11)

an imaging board on which an imaging device is mounted;
an image pickup flexible provided with wiring for driving the image pickup element;
a radiator plate for dissipating heat from the imaging element;
a thermally conductive member;
The imaging board and the imaging flexible board are connected via a connecting portion,
The connecting portion is arranged between the imaging substrate and the heat sink,
The image pickup apparatus, wherein the thermally conductive member is arranged between the image pickup substrate and the image pickup flexible plate and between the image pickup flexible plate and the heat sink. 2. The imaging apparatus according to claim 1, wherein hardness of said heat conducting member is lower than hardness of said imaging substrate and hardness of elements mounted on said imaging substrate. the connecting portion connecting the imaging board and the imaging flexible board is a board-to-board connector;
The board-to-board connector is mounted on the imaging flexible board,
3. The imaging flexible board according to claim 1, wherein a reinforcing plate is attached to the surface opposite to the surface on which the board-to-board connector is mounted so as to overlap the board-to-board connector. imaging device. 4. The imaging device according to claim 3, wherein the reinforcing plate is made of metal or glass epoxy resin. 5. The imaging apparatus according to claim 3, wherein hardness of said heat conducting member is lower than hardness of said reinforcing plate. 6. The imaging apparatus according to claim 1, wherein the thermally conductive member is made of silicone rubber or a putty-like member. 7. The imaging apparatus according to any one of claims 1 to 6, wherein a space is provided around the heat conducting member to allow the excess heat conducting member to escape. The thermally conductive member includes a substrate-side thermally conductive member arranged between the imaging substrate and the imaging flexible board, and a radiator plate-side thermally conductive member arranged between the imaging flexible board and the radiator plate,
The imaging device according to any one of claims 1 to 7, wherein hardness of the board-side heat-conducting member is lower than hardness of the heat-dissipating plate-side heat-conducting member. The imaging flexible board includes a drawer section that is drawn out from a location where the reinforcing plate is attached,
6. The image pickup apparatus according to claim 3, wherein the lead-out portion is sandwiched between the heat-conducting members. 10. The imaging apparatus according to any one of claims 1 to 9, wherein the thermally conductive member is arranged so as to include at least part of the projection area of the sensor chip of the imaging element. 11. The image pickup apparatus according to claim 1, wherein the heat dissipation plate is provided with heat dissipation fins.

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