JP3459468B2 - Electronic equipment cooling device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device applicable to electronic equipment such as a video camera and an electronic camera provided with an electronic device that generates heat during operation such as a solid-state image pickup device.

[0002]

2. Description of the Related Art Conventionally, an electronic apparatus such as a video camera or an electronic camera uses a solid-state image pickup device such as a CCD and an image pickup device for picking up an image formed on the device through an optical lens. However, when the image pickup apparatus as described above is driven, the solid-state image pickup element and its drive circuit generate heat, and the dark current increases as the temperature of the solid-state image pickup element rises due to the heat generation, so that the image deteriorates. Dark current is 10
There is about a two-fold increase per degree Celsius, and even an element with a small driving power rises around 10 degrees Celsius, which makes it difficult to drive the element stably with good characteristics. In particular, when the amplifier gain is increased or the charge accumulation time is lengthened to obtain high sensitivity under dark photographing conditions, the influence of the dark current becomes large and the image deterioration becomes remarkable. Therefore, in order to suppress the dark current and drive the solid-state image sensor with good characteristics, it is conceivable to drive the solid-state image sensor while cooling.

Several methods have already been proposed as a cooling device for an electronic device equipped with a solid-state image pickup device or a constant temperature method by cooling. For example, the actual Kaihei 5-29 shown in FIG.
For example, there is one described in Japanese Patent No. 2366, "Cooling Device for Electronic Equipment". A cylinder 8 including a piston 7 slidably fitted inside is connected to a Peltier element 2, the tip of the piston 7 is formed into a spherical surface, and slidably fitted along the spherical surface. The movable spacer 6 thus formed is in parallel contact with the back surface of the solid-state imaging device 1 via the piston 7, and is pressed by the coil spring 9. The heat radiation side of the Peltier element 2 is connected to a loop type thin tube heat radiation pipe 10, and heat is radiated to the outside of the camera housing through this pipe. The concave surface of the free spacer 6 is the piston 7
Since the cylindrical side wall of the cylinder 8 is in contact with the convex side surface of the cylinder 8, and the cylindrical side surface of the piston 7 is in contact with the two grinding surfaces, there is a degree of freedom in both rotational movement and longitudinal movement.
It is possible to prevent mechanical stress from being applied to the solid-state imaging device even if the mounting position or mounting posture of the Peltier device varies.

[0004]

However, in the prior application, there are two grinding surfaces (between the spacer 6 and the piston 7 and between the piston 7 and the cylinder 8) between the heating element 1 and the electronic cooling element 2. Therefore, there is a drawback that the heat transfer efficiency is deteriorated. That is, a small gap is required for the mating surface to be movable, and a fluid consisting of gas or liquid exists in this gap, but the thermal conductivity of gas or liquid is higher than that of solid. It is clear that it is extremely bad. For example, the thermal conductivity of air at 0 ° C is 2.41
× 10 -2 W / mK, oil thermal conductivity is 0.136 W / mK
In comparison, the thermal conductivity of copper is 403 W / mK, which is about 3 orders of magnitude worse. In addition, a complicated buffer mechanism including a flexible spacer has a drawback that the heat transfer effect is deteriorated if it is not manufactured with precision, and it is not easy to manufacture at low cost and the weight is increased. Further, the buffering electrothermal mechanism including the spacers and the like has a drawback that the heat capacity and the surface area are large and a heavy load is applied to the cooling of the Peltier element. Therefore, an object of the present invention is to eliminate the above-mentioned problems, cool an electronic device including an electronic device that generates heat during operation, and have a simple structure that has an expandable and contractible heat conduction mechanism that does not reduce cooling efficiency. It is intended to provide a device.

[0005]

A cooling device for electronic equipment according to the present invention for achieving the above object is an electronic equipment having an electronic device that generates heat during operation. In this case, the electronic cooling element is closely attached to the electronic device that generates heat. And a heat-dissipating heat pipe for transporting heat to the outside of the electronic device, and a metal bellows including a bellows of a flat metal plate or a round metal plate having excellent thermal conductivity, and the electronic cooling element. The metal bellows is thermally adhered between the heat pipe and the heat pipe.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cooling device in which the device of the present invention is applied to a color CCD camera will be described below with reference to the accompanying drawings, FIG. 1 and FIGS. FIG. 1 shows a first embodiment using a bellows-type bellows as an expandable and contractible heat conduction mechanism. One end of the bellows 3 is brought into close contact with the heat radiation side of the Peltier element 2 whose heat absorption side is brought into close contact with the CCD 1, and a heat pipe 4 which is a rod-shaped or plate-shaped heat radiation member is brought into close contact with the other end. The bellows 3 is a small one made of a material having excellent thermal conductivity such as aluminum, copper or alloys thereof. The heat radiation side of the Peltier element 2 is silver paste or
It is adhered with a solvent-free epoxy-based thermally conductive adhesive compounded with silver fella or low temperature solder. The other end of the bellows 3 is also closely attached to the heat pipe 4.
The bellows is structurally excellent in stretchability and has mechanical degrees of freedom such as rotation, tilting and tilting. In particular, a welded bellows can be made small and short but having a small spring constant.

Further, a detailed structural example of this bellows is shown in FIG.
Will be explained. In FIG. 3 (a), bellows are arranged so as to surround four sides, and flat metal plates are attached to both ends thereof to facilitate thermal contact. FIG. 3B shows a plurality of bellows arranged in parallel. FIG. 3 (c) has a round bellows. Further, these examples may be combined or cut out, and may be transformed as shown in FIG. Also, by changing the number of bellows steps,
The maximum deformation amount can be designed arbitrarily. FIG. 4 specifically shows an example of a method of manufacturing and processing a bellows as a sectional view. Figure 4 (a)
Is manufactured by bending, FIG. 4 (b) is manufactured by welding, and FIG. 4 (c) is manufactured by pressing or extrusion. In either case, the same effect can be obtained.

FIG. 5 shows an overall view when the first embodiment is used, and shows an example of attachment to a color CCD camera. A circuit board 15 is attached to the rear of the camera, and a lens 16 is attached to the front of the camera. The light entering through the lens 16 is R by the prism 11.
It is decomposed into (red), G (green), and B (blue) light. CCDs are attached to the light outlets of the prisms 11, respectively. The present invention is similarly applied to the CCDs 1R, 1G, and 1B of R, G, and B to perform cooling. 2R, 2G, 2B are Peltier elements for cooling, and 3R, 3G, 3B are bellows having thermal conductivity. Each heat pipe 4R, 4 for heat dissipation
G and 4B are arranged so as to face upward, and three from the upper part of the outer casing 14 of the camera body are brought out together. A plurality of radiating fins 12 are attached to the portion where each heat pipe projects from the housing to the outside, and the heat pipe and the radiating fin are thermally adhered to each other with solder or the like. The surface area of the heat radiation fins 12 is large, and by blowing the heat by the fan 13 so as to remove the heat, the heat can be efficiently released to the outside air. The shape and arrangement of the heat pipe, the outlet of the heat pipe from the housing, and the like may be changed according to the shape of the camera housing and the arrangement of the internal drive circuit. Further, although the CCD is used as the solid-state image sensor in the embodiment of the present invention, other solid-state image sensors such as MOS type and AMI type may be used.

FIG. 6 shows a second embodiment using a wide ribbon-like structure having a structure in which a large number of fine wires of good heat conductive metal are arranged as an expandable and contractible heat transfer mechanism. The heat absorption side of the Peltier element 2 is brought into close contact with the CCD 1, and one end of a wide ribbon-like member 5 in which a large number of fine wires of good heat conductive metal are arranged is brought into close contact with the heat radiation side of the Peltier element 2, and the other end is rod-shaped. It is brought into close contact with the heat pipe 4 having a plate shape. The above-mentioned two joints are adhered to each other in the same manner as in the first embodiment. The wide ribbon-shaped thin metal wire 5 having good thermal conductivity may be a long and wide knitted wire in addition to a large number of thin metal wires arranged side by side. For easier mounting, flat heat transfer plates 17 made of a metal having good thermal conductivity such as copper may be mounted on both ends, as shown in FIG. A wide ribbon-like member 5 having a large number of fine wires made of a metal having good heat conductivity is preferably bent so as to have a high degree of mechanical freedom, and its shape is elliptical or zigzag. It can be freely transformed, such as a cut-out part.

In the cooling device according to the present invention, the heat from the heat radiation side of the Peltier device for directly cooling the solid-state image pickup device can be efficiently sent to the heat pipe. The heat flowing into the evaporation part of the heat pipe is carried in the pipe by the latent heat flow of the liquid phase and the gas phase of the working fluid enclosed in the heat pipe, and is drawn upward to the upper part of the outer casing of the camera body. Exit through
The heat pipe is discharged to the outside from the condensing part of the heat pipe. A heating element is directly connected to the evaporating part of the plate-shaped heat pipe, a heat radiating fin is attached to the heat radiating side, and the temperature change between the evaporating part and the condensing part of the heat pipe when the fin is air-cooled is shown in FIG. Show. The figure shows the measurement of the temperature rise when a heat amount of about 1.2 J (joule) per second is applied to the heating element. T1 represents the temperature rise of only the heating element when this amount of heat is applied, and is shown by the difference between the temperature of the heating element and room temperature, which is 45 ° C. after 20 minutes. The temperature of the evaporation part when the heating element is connected to the heat pipe is T2, and the temperature of the heat radiating part of the heat pipe is T3 at the same time, which is shown by the difference from the room temperature. From FIG. 8, it can be seen that the difference between T2 and T3 is extremely small, and the heat pipe has a sufficient heat transport ability.

FIG. 9 shows an example of the temperature measurement results using the same heat generating element and heat pipe as described above using the expandable heat conduction mechanism shown in the first embodiment of the present invention. The temperature of the joint between the heating element and the bellows at this time is T4, and the temperature of the heat radiating portion of the heat pipe is T5, which are shown as the difference from room temperature. T2 and T3 are the same as those with the same symbols in FIG. From the result that the temperature difference between T4 and T5 is small, it is clear that the present invention is a device having excellent thermal conductivity. Further, in an example in which the present invention is applied to a color CCD camera for broadcasting, the temperature of the CCD can be lowered by 30 ° C. as compared with the conventional case, and the dark current is about 1/10.
Decreased to. Therefore, a good image was obtained even if the amplifier gain of the camera was increased and used or the charge accumulation operation was performed for a long time. In the above embodiments, the case where the electronic device is a solid-state image pickup element has been described, but the present invention is not limited to this, and various semiconductor elements, semiconductor integrated circuits, display elements, etc. are operating as the electronic device. It will be apparent that the cooling device of the present invention is suitable for application to a device that generates heat and deteriorates its characteristics.

[0012]

As described above in detail, by applying the cooling device according to the present invention, in an electronic apparatus having an electronic device that generates heat during operation, the amount of heat generated by the electronic device can be determined by the Peltier element and the heat. Heat can be effectively dissipated through the pipe, and when the electronic device is a solid-state image sensor, it is possible to suppress an increase in dark current during operation and contribute to stabilization of the operation and performance improvement of the solid-state image sensor. it can. Further, since the cooling device of the present invention has not only thermal conductivity but also elasticity, it does not give mechanical stress to electronic components such as a solid-state imaging device or a Peltier device and is stable for a long period of time. Can be operated.

[Brief description of drawings]

FIG. 1 is a sectional view of a cooling device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a conventional cooling device example.

FIG. 3 is a diagram showing an example of the shape of an expandable and contractible heat transfer mechanism of the first embodiment.

FIG. 4 is a view showing an example of processing the expandable heat conduction mechanism of the first embodiment.

FIG. 5 is a cross-sectional view of an example in which the device of the present invention is attached to the outer case of a color CCD camera.

FIG. 6 is a sectional view of a cooling device according to a second embodiment of the present invention.

FIG. 7 is a diagram showing an example of attachment of a heat transfer plate to an expandable and contractible heat transfer mechanism of the second embodiment.

FIG. 8 shows an example of the measurement result of the operation of the heat pipe.

FIG. 9 is an example of a temperature measurement result using the heat conduction mechanism according to the present invention.

[Explanation of reference numerals] 1 solid-state image pickup element (heating element) 2 electronic cooling element 3 bellows (expandable heat conduction mechanism) 4 heat dissipation heat pipe 5 ribbon of fine heat conductive metal (expandable Heat conduction mechanism 6 Flexible spacer 7 Piston 8 Cylinder 9 Coil spring 10 Loop type thin pipe heat radiation pipe 11 Prism 12 Radiation fin 13 Fan 14 Camera outer casing 15 Circuit board 16 Lens 17 Heat transfer plate

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumihiko Ando 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside the Broadcasting Research Laboratories, Japan Broadcasting Corporation (56) Reference JP-A-2-54975 (JP, A) Flat 4-10469 (JP, U) Special Table Flat 6-510638 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 23/38 H01L 23/427 H04N 5/335

Claims (3)

(57) [Claims] 1. An electronic device including an electronic device that generates heat during operation, an electronic cooling element that is in close contact with the electronic device that generates heat, a heat radiating heat pipe that transports heat to the outside of the electronic device, and thermal conductivity. An excellent flat metal plate snake
A bellows or a metal bellows formed of a bellows of a round metal plate, and cooling the electronic device characterized in that the metal bellows is thermally adhered between the electronic cooling element and the heat pipe. apparatus. 2. The cooling device for electronic equipment according to claim 1, wherein the electronic device is a solid-state image sensor. 3. A snake made of a flat metal plate having excellent thermal conductivity.
3. The cooling device for electronic equipment according to claim 1, wherein the bellows or the bellows of the round metal plate is copper, aluminum, nickel, iron, or an alloy containing at least one of these metals.