Imaging device

Abstract

To provide an imaging apparatus that achieves appropriate heat radiation from an infrared emitting diode and can prevent a reduction in waterproof performance due to creep deformation of a resin housing.SOLUTION: An imaging apparatus has: a housing that includes a cover part and a base part and is formed of resin; a camera part that is accommodated inside the housing; a circuit board that is fixed to the base part and has an infrared emitting diode mounted on a surface facing the cover part; a heat radiation member that is arranged between the circuit board and the base part and radiates heat from the infrared emitting diode; and a sealing member that is arranged on an outer periphery of the housing while being pressed by the cover part and the base part. The infrared emitting diode is arranged closer to the sealing member in a space between the camera part and the sealing member. The heat radiation member is not in contact with an inner peripheral wall of the housing. A first heat insulating space is formed between the heat radiation member and the base part to overlap the infrared emitting diode when seen from the cover part.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an imaging device.

Background Art

[0002] Conventionally, in order to suppress the intrusion of water such as rain, a network camera having a waterproof structure has been proposed. Also, in order to record good images even in a dark environment, a network camera equipped with an infrared light-emitting diode (IR LED) has been proposed (see Patent Document 1). Since the irradiation efficiency of the IR LED decreases as the temperature rises, a network camera equipped with an IR LED needs to have a heat dissipation structure.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, network cameras have been required to use resin casings formed of resin in order to reduce weight and cost. In the imaging device of Patent Document 1, in order to have a waterproof structure while using a resin casing, for example, a gasket or the like may be arranged on the outer periphery of the casing. However, in the imaging device of Patent Document 1, the substrate on which the IR LED is mounted is in direct contact with the casing, and the IR LED is arranged at a position close to the outer periphery of the casing. Therefore, when a certain stress acts at a certain temperature at a location where the reaction force of the gasket is applied, creep deformation occurs in which the deformation of the location where the stress acts increases over time, and there is a risk that the amount of gasket pressing of the casing decreases. As a result, the sealing performance of the gasket may deteriorate, and there is a risk that the waterproof performance cannot be ensured. Also, if the substrate is arranged so as not to be in direct contact with the casing, the heat of the IR LED cannot be sufficiently dissipated, and there is a risk that the irradiation efficiency of the IR LED will decrease.

[0005] An object of the present invention is to provide an imaging device capable of realizing appropriate heat dissipation of an infrared light emitting diode and suppressing a decrease in waterproof performance due to creep deformation of a resin housing.

Means for Solving the Problems

[0006] An imaging device according to one aspect of the present invention includes a cover portion and a base portion, a housing formed of resin, a camera portion housed in the housing, a circuit board fixed to the base portion and having an infrared light emitting diode mounted on a surface on the cover portion side, a heat dissipation member disposed between the circuit board and the base portion for dissipating heat of the infrared light emitting diode, and a sealing member disposed on the outer periphery of the housing while being pressed by the cover portion and the base portion. The infrared light emitting diode is disposed on the side closer to the sealing member in a space between the camera portion and the sealing member. The heat dissipation member does not contact the inner peripheral wall of the housing, and a first heat insulating space is formed between the heat dissipation member and the base portion so as to overlap the infrared light emitting diode when viewed from the cover portion side. and the base portion includes a wall that blocks the first heat-insulating space and the camera portion It is characterized by the above.

Effects of the Invention

[0007] According to the present invention, it is possible to provide an imaging device capable of realizing appropriate heat dissipation of an infrared light emitting diode and suppressing a decrease in waterproof performance due to creep deformation of a resin housing.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same members are denoted by the same reference numerals, and redundant descriptions are omitted.

[0010] FIG. 1 is an overall view of a network camera 100 which is an example of an imaging device according to an embodiment of the present invention. The network camera 100 has a housing 130 and a lens protection member 140, and is capable of shooting and recording images.

[0011] The housing 130 includes a cover portion 110 and a base portion 120. The cover portion 110 and the base portion 120 can each be manufactured by resin molding such as polycarbonate. The base portion 120 is fixed to a wall or a vehicle with screws or the like through installation holes. The cover portion 110 and the base portion 120 each include a fastening portion 150 and are fastened to each other with screws or the like. In the present embodiment, the housing 130 is composed of two parts, but may be composed of three or more parts. Also, the cover portion 110 and the base portion 120 may be fixed using claw fitting or adhesion.

[0012] The cover portion 110 includes a window (window portion) 160 for irradiating light (IR light) from an infrared light emitting diode (IR LED). The window 160 is integrally formed with the cover portion 110 and is made of, for example, black transparent polycarbonate. Note that the window 160 may be adhesively fixed to the cover portion 110 or may be screw-fixed together with a waterproof member. The inner side of the window 160 inside the housing has a lens shape and can collect or diffuse IR light. By irradiating IR light, shooting is possible even in a dark environment such as at night. The window 160 is located substantially in the middle of the fastening portion 150. Thereby, the irradiation range of the IR LED can be widened. The window 160 is colored in a color that blocks visible light and transmits IR light. Thereby, the components inside the housing cannot be seen from the outside. The wavelength of the IR light is approximately from 750 nm to 950 nm.

[0013] The lens protection member 140 is hemispherical and protects the lens and other components housed inside the housing from impacts and dust. The lens protection member 140 is fixed to the cover portion 110 by ultrasonic welding or the like. Since the network camera 100 captures images through the lens protection member 140, the lens protection member 140 is treated as an optical component, and transparency and dimensional accuracy are important. The lens protection member 140 is made of, for example, transparent polycarbonate or the like.

[0014] Figure 2 is a cross-sectional view of the network camera 100. Inside the housing, a gasket (sealing member) 180, a camera unit 200, a circuit board 300, an IR LED 320, a heat dissipation member 340, and a holding member 360 are housed. The gasket 180 is made of, for example, silicone rubber or the like and is disposed on the outer periphery of the housing while being pressed at the boundary between the cover portion 110 and the base portion 120. Here, the outer periphery includes not only the case where it is strictly the outer periphery but also the case where it is substantially the outer periphery (approximate outer periphery). The gasket 180 has a substantially rhomboid shape and is configured to reduce the reaction force when pressed. By pressing the gasket 180, the adhesion of the gasket 180 to the housing 130 is enhanced and the sealing performance is exhibited. This is the same as the sealing structure of an O-ring. The housing 130 has a sealed structure by the lens protection member 140, the window 160, and the gasket 180, and it is possible to prevent water and dust from entering the inside of the housing 130. Note that the shape of the gasket 180 may be another shape with less reaction force, such as an X shape or an elliptical shape. Also, as the gasket 180, a waterproof sealing material or a foam may be used.

[0015] The camera unit 200 is disposed at approximately the center of the housing, and includes a lens 210, a lens holder 230, an imaging substrate 240, a lens cover 250, and a camera holder 260. The lens 210 is screwed and held in the lens holder 230 and is movable in the optical axis direction to adjust focus. The imaging substrate 240 includes an imaging element and is fixed to the lens holder 230 by adhesion or the like. The imaging element is one of the heat generating components. When the temperature of the imaging element becomes too high, noise occurs in the video. Therefore, it is necessary to dissipate the heat of the imaging element to the lens cover 250 or the like and to adopt a structure that does not receive the draft of heat from another heat source such as a substrate. For example, a method of forming a wall that blocks the movement of heat and insulating is conceivable. The lens holder 230 is gripped and fixed by the lens cover 250. The lens cover 250 is made of, for example, metal die casting or resin molding such as polycarbonate, and is held so as to be covered by the camera holder 260 and the base portion 120, and is configured to be capable of tilting and rotating operations. An opening for video shooting is formed in front of the lens cover 250, and a hole for passing a wire 270 or the like is formed behind the lens cover 250. The camera holder 260 is made of, for example, resin molding such as polycarbonate, and is continuously open from a substantially horizontal position to a substantially vertical position that is the shooting range. Further, the camera holder 260 regulates the tilting operation range of the lens cover 250.

[0016] The holding member 360 is made of, for example, resin molding such as polycarbonate, holds the camera unit 200 via the camera holder 260 so as to be pan-rotatable, and is fixed to the base portion 120 using screws or the like. The pan rotation axis is substantially perpendicular to the installation surface. The holding member 360 has an opening so as not to block the irradiation of IR light from the IR LED 320. Further, the holding member 360 includes ribs 364 so as to surround the periphery of the IR LED 320. The ribs 364 prevent the IR light from the IR LED 320 from passing through the inside of the housing 130 and entering the lens 210. Further, the ribs 364 prevent the air heated by the IR LED 320 from moving to the side of the camera unit 200 and make it difficult to transfer heat to the camera unit 200.

[0017] The circuit board 300 is fixed to the base portion 120 using screws or the like, and is responsible for the control functions of the entire network camera 100, such as the control of the IR LED 320, power supply, camera control, and connection to the network. An opening is formed in the central portion of the circuit board 300, and the camera unit 200 is disposed within the opening. The circuit board 300 and the imaging board 240 are electrically connected by a wire 270 or the like. Note that the circuit board 300 and the imaging board 240 may be electrically connected by a flexible board, a flat cable, a fine wire coaxial cable, or the like. The camera unit 200 converts the light received through the lens protection member 140 and the lens 210 into an electrical signal by an imaging device, and transmits it to the circuit board 300. The circuit board 300 records the received video data or distributes it on the network. The IR LED 320 is mounted on the upper surface of the circuit board 300 and is disposed closer to the gasket 180 in the space between the camera unit 200 and the gasket 180. Thereby, the IR LED 320 can be brought as close as possible to the cover portion 110 and the window 160, and the irradiation angle can be kept wide. Also, by distancing the IR LED 320 from the camera unit 200, the mutual thermal influence can be reduced.

[0018] The heat dissipation member 340 is made of a metal plate with high thermal conductivity such as aluminum, and is disposed between the circuit board 300 and the base portion 120. Note that the heat dissipation member 340 may be made of another metal material such as copper, or may be made in combination with a heat diffusion member such as a graphite sheet. The heat dissipation member 340 includes an extension portion 344 close to the lower surface of the circuit board 300, and dissipates the heat of the IR LED 320 from the lower surface side of the circuit board 300. The heat transfer member 370 is disposed in a state of being sandwiched between the extension portion 344 and the circuit board 300, making it easier to transfer the heat of the IR LED 320 to the heat dissipation member 340. Note that, without providing the heat transfer member 370, the extension portion 344 may function as a contact portion that contacts the circuit board 300. Further, a heat insulation portion (first heat insulation space) 380 is formed between the extension portion 344 and the base portion 120 so as to overlap the IR LED 320 when viewed from the side of the cover portion 110. The heat dissipation member 340 is in contact with the base portion 120 at a position away from the gasket 180 on the central side rather than the heat insulation portion 380. Further, the heat dissipation member 340 is not in contact with the inner peripheral wall 121 of the base portion 120.

[0019] A plurality (two in this embodiment) of IR LEDs 320 are accommodated inside the housing. The two IR LEDs 320 are arranged substantially point-symmetrically (at equal intervals along the rotation direction centered on the pan rotation axis) about the pan rotation axis of the camera unit 200. Therefore, the irradiation range of the IR LED 320 covers the entire circumference of the network camera 100. Thereby, in a dark shooting environment, the camera unit 200 can perform shooting regardless of the pan rotation position. Further, a plurality (two in this embodiment) of heat dissipation members 340 are accommodated inside the housing. The two heat dissipation members 340 are arranged substantially point-symmetrically (at equal intervals along the rotation direction centered on the pan rotation axis) about the pan rotation axis of the camera unit 200, and dissipate the heat of the corresponding IR LED 320. Note that, in this embodiment, the number of the IR LEDs 320 and the heat dissipation members 340 is two, but it may be three or more.

[0020] FIG. 3 is a cross-sectional view of the network camera 100. Hereinafter, heat dissipation of the IR LED 320 will be described. First, heat dissipation by heat conduction will be described. Heat generated during irradiation of IR light by the IR LED 320 is directly transmitted to the circuit board 300. Then, it is transmitted from the lower surface side of the circuit board 300 to the extension portion 344 of the heat dissipation member 340 via the heat transfer member 370. Since the heat dissipation member 340 has a high thermal conductivity, the heat transmitted to the extension portion 344 is diffused in the plane direction of the heat dissipation member 340. Since the heat dissipation member 340 is fixed to the base portion 120 at a location avoiding the heat insulation portion 380, the heat transmitted to the heat dissipation member 340 is transmitted to the housing 130 from locations other than the heat insulation portion 380 and dissipated to the outside of the housing 130.

[0021] Next, heat dissipation by heat convection will be described. On the upper surface side of the circuit board 300, the air heated by the IR LED 320 convects in the LED space (second heat insulation space) 390 surrounded by the rib 364 and the circuit board 300 and is dissipated from the window 160 to the outside of the housing. Since the rib 364 prevents heat from convecting on the side of the camera unit 200, the camera unit 200 and the IR LED 320 are less likely to be affected by each other's heat. Also, on the lower surface side of the circuit board 300, the air in the heat insulation portion 380 is heated by the heat transmitted from the IR LED 320 to the extension portion 344. However, since solids generally have a higher thermal conductivity than gases, most of the heat of the IR LED 320 is diffused in the plane direction of the heat dissipation member 340 through the heat conduction path described above. Thereby, it is possible to prevent the air in the heat insulation portion 380 from becoming too hot. Also, a wall 122 is formed on the base portion 120 to prevent the air directly heated from the lower surface of the circuit board 300 from moving to the side of the camera unit 200, blocking the heat insulation portion 380 and the camera unit 200. Further, in the projection plane viewed from above the housing (when viewed from the side of the cover portion 110), the heat insulation portion 380 and the LED space 390 are formed to overlap. Thereby, the heat of the IR LED 320 can be concentrated on the extension portion 344, and the heat can be quickly diffused by the heat conduction of the heat dissipation member 340 which is a solid.

[0022] By dissipating heat from the IR LED 320 with the above-described configuration, it is difficult for the heat of the IR LED 320 to be transmitted to the vicinity of the IR LED 320 in the base portion 120 or to the camera portion 200.

[0023] In the present embodiment, in order to ensure the waterproof performance of the housing, the gasket 180 is disposed in a pressed state. Therefore, the reaction force of the gasket 180 acts on the cover portion 110 and the base portion 120 in a direction in which they open from each other. Since the base portion 120 has a shape closer to a plate shape than the cover portion 110, it has low rigidity and is easily deformed. In addition, the position A, which is in the vicinity where the IR LED 320 of the base portion 120 is disposed, is far from the fastening portion 150 and is thus easily deformed. If the position A where the reaction force of the base portion 120 acts is heated, creep deformation may occur. When the base portion 120 is deformed, the pressing amount of the gasket 180 decreases. As a result, the sealing performance of the gasket 180 deteriorates, and there is a risk that the waterproof performance cannot be ensured.

[0024] In the present embodiment, the heat dissipation member 340 and the heat insulation portion 380 make it difficult for heat to be transmitted to the position A of the base portion 120. That is, since the high temperature that causes creep deformation can be suppressed, the occurrence of creep deformation can be suppressed.

[0025] As described above, according to the configuration of the present embodiment, it is possible to provide an imaging device that can realize appropriate heat dissipation of the infrared light-emitting diode and suppress a decrease in waterproof performance due to creep deformation of the resin housing.

[0026] As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist thereof.

Explanation of Reference Numerals

[0027] 100 Network camera (imaging device) 110 Cover portion 120 Base portion 121 Inner peripheral wall 130 Housing 180 Gasket (sealing member) 200 Camera unit 300 Circuit board 320 Infrared light-emitting diode 340 Heat dissipation member 380 Heat insulation part (heat insulation space)

Claims

1. A housing formed of resin, comprising a cover portion and a base portion, A camera unit housed in the housing, A circuit board fixed to the base portion and having an infrared light-emitting diode mounted on a surface on the cover portion side, A heat radiating member disposed between the circuit board and the base portion for radiating heat of the infrared light-emitting diode, And a sealing member disposed on the outer periphery of the housing while being pressed between the cover portion and the base portion, The infrared light-emitting diode is disposed closer to the sealing member in a space between the camera unit and the sealing member, The heat radiating member does not contact the inner peripheral wall of the housing, A first heat insulating space is formed between the heat radiating member and the base portion so as to overlap the infrared light-emitting diode when viewed from the cover portion side. The base portion includes a wall that blocks the first heat insulating space and the camera unit. An imaging device characterized by this.

2. The imaging device according to claim 1, further comprising a holding member disposed between the cover portion and the circuit board and rotatably holding the camera unit.

3. The imaging device according to claim 2, wherein the holding member includes ribs that cover the periphery of the infrared light-emitting diode.

4. The imaging device according to claim 3, wherein the infrared light-emitting diode is disposed inside a second heat insulating space surrounded by the rib and the circuit board.

5. The imaging device according to claim 4, wherein the first heat insulating space and the second heat insulating space are formed so as to overlap when viewed from the cover portion side.

6. The imaging device according to any one of claims 1 to 5, wherein the heat radiating member includes a contact portion that contacts the circuit board.

7. The imaging device according to any one of claims 1 to 5, further comprising a heat transfer member disposed in a state of being sandwiched between the circuit board and the heat dissipation member.

8. The imaging device according to any one of claims 1 to 7, wherein the camera unit is disposed in an opening formed in the center of the circuit board.

9. The imaging device according to any one of claims 1 to 8, wherein the number of the infrared light emitting diodes and the heat dissipation members is plural.

10. The imaging device according to claim 9, wherein the plurality of infrared light emitting diodes and the plurality of heat dissipation members are arranged at equal intervals along a rotation direction centered on the pan rotation axis of the camera unit.

11. The imaging device according to any one of claims 1 to 10, wherein the heat dissipation member is in contact with the base portion on a central side of the first heat insulation space.

12. The imaging device according to any one of claims 1 to 11, wherein the cover portion includes a window portion through which light of the infrared light emitting diode passes.

Images