JPH0729849U - Heat dissipation device for portable electronic devices - Google Patents

Abstract

(57) [Abstract] [Purpose] Efficiently dissipates heat generated in the semiconductor devices that compose electronic devices even after continuous use for a long time. [Structure] A semiconductor device (heating element) 12 incorporated in a hermetically sealed case 10 is made of a material having good thermal conductivity such as aluminum in a cylindrical or flat plate shape in the longitudinal direction of a heat pipe 20 for heat radiation. One end (heat-receiving part) of each of these is closely or indirectly connected, and the other end (heat-dissipating part) is joined to a heat sink (microphone protective metal fitting) 14 exposed to the outside air. When using a cylindrical one in the heat pipe 20, the heating element or the heat sink is closely contacted or indirectly connected, and at least one of both ends in the longitudinal direction of the heat pipe 20 is processed into a flat plate shape, The vicinity of the center may be made into an original cylindrical state without being subjected to flattening.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a semiconductor device having a high heat generation density, which is used in a portable wireless device, a video camera, and the like, in particular, an electronic device having a sealed structure, and a heat dissipation device for electronic components around the semiconductor device.

[0002]

[Prior art]

 In recent years, semiconductor devices, especially large-scale integrated circuits and arithmetic processing devices, have achieved even higher speeds and higher densities (higher integration), and are equipped with this semiconductor device for use in consumer-use portable wireless devices (for example, cordless telephones). ) And video cameras and other electronic devices are rapidly becoming smaller. Further, in the electronic devices, due to the expansion of the environment in which they are used, an outer case having a good airtightness has come to be used in order to protect the internal electronic circuit from dust and water droplets.

[0003]

[Problems to be solved by the device]

 For example, the electronic device is frequently used for long hours while charging a wireless device of a cordless telephone, and for a video camera, continuous use over an extremely long period of time is typified by a monitor at a store. Came.

The electric power consumption of the electronic devices is about 7 watts at the maximum, but since these devices are originally designed to be used for a fixed period of time, they can be used continuously for a long time as described above, or In order to respond to the recent miniaturization of electronic devices, it is required to reduce the space for arranging the components, and semiconductor devices placed under these conditions generate unpredictable heat, which leads to the above-mentioned miniaturization. As a result, the heat of the semiconductor device is transferred to electronic parts located in the vicinity, such as cylinders, heads, motors, etc. that are in close contact with the video tape in video cameras, and these electronic parts also generate heat. There is a problem.

Further, as described in “Prior Art”, since the semiconductor device housed in the outer case having a good airtightness does not have a special heat radiation means, the heat of the semiconductor device is hard to be released to the outside. Therefore, depending on the constitution, it may cause low-temperature burns, or even cause anxiety to the user even if no burns are caused.

[0006]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, in the present invention, a heat-radiating heat pipe in which a semiconductor device (heating element) incorporated in a sealed outer case is made of a material having good thermal conductivity such as aluminum in a cylindrical or flat plate shape. One end (heat receiving part) in the longitudinal direction is closely contacted or indirectly connected, and the other end (heat dissipation part) is joined to the heat sink exposed to the outside air.

When a cylindrical heat pipe is used, at least one of the longitudinal ends of the heat pipe, which is in close contact with the heating element or the heat sink, is processed into a flat plate shape, and the vicinity of the center is processed into a flat surface. It may be in the original cylindrical state without being applied.

Further, the heat radiating portion of the heat pipe may be integrated with the case so as not to adversely affect the design of the outer case, or may be attached to a heat sink exposed to the outside air as a separate component.

As is well known, the heat pipe means, as shown in FIG. 4, the inside of a cylindrical or planar container 22 having a good heat conductivity such as copper, aluminum, etc. However, a wick 24 having a large capillary force is provided in the inside of the planar container 22, and a fluid called a working fluid that easily changes alternately into a gas layer and a liquid layer (for example, water, alcohol, etc.) is injected into the working fluid. After injecting an appropriate amount through the inlet 26, the inlet 26 is sealed.

The operating principle is that, when heat is generated in the evaporating part (heat receiving part) at one end of the planar container 22, the working fluid enclosed inside evaporates, and the generated steam has a temperature lower than that of the evaporating part. The liquid moves to the condensing part (heat radiating part) at the other end of the flat container 22 and changes into a liquid, and this liquid is returned to the evaporating part by the capillary force of the wick 24. Due to this latent heat of vaporization, a large amount of heat is transported from one end to the other end with a slight temperature difference.

Note that in the heat pipe shown in FIG. 4, the heat receiving portion and the heat radiating portion may be arranged at opposite positions, and in the installed state, the heat radiating efficiency is higher as the heat radiating portion is placed higher.

[0012]

[Action]

 As in the above configuration, the heat receiving portion of the heat pipe is closely attached to the semiconductor device (heating element) incorporated in the sealed outer case, and the heat radiating portion is provided integrally with the outer case or as a separate component. If attached to a heat sink (radiator), the heat of the heating element can be positively radiated to the outside air.

Further, when the heat pipe has a cylindrical shape, as shown in FIG. 5, the heat receiving portion and the heat radiating portion of the heat pipe 20 are respectively attached to the semiconductor device 12 and the heat sink (not shown) such as brazing having excellent thermal conductivity. If the adhesive material 4 can make a close contact, the cross section of the heat pipe 20 can be kept circular as shown in FIG. 5, and therefore the cross sectional area can be maximized. As is well known, in a heat pipe, the larger the cross-sectional area, the better the heat radiation effect.

However, in the above-mentioned means, the adhesive material 4 such as brazing which is excellent in heat conductivity in practice is very expensive, and even in the brazing work, the heat dissipation effect cannot be sufficiently exerted unless this work is surely performed. However, it is very troublesome in the manufacturing process. Therefore, as described above, at least one of the heat receiving portion and the heat radiating portion uses an adhesive agent 4 such as brazing by forming a cylindrical container 22 into a flat plate shape and making direct surface contact with the semiconductor device 12 as shown in FIG. Even without it, it is possible to minimize the decrease in thermal conductivity.

[0015]

【Example】

 As an example of the present invention, a video camera in which the above-mentioned protective metal member for a microphone also shares a heat sink is shown in FIG. 1, and a heat pipe is a semiconductor device (hereinafter referred to as a “heating element”) in the AA cross section of FIG. Fig. 2 shows an enlarged view of the area around 12. In FIGS. 1 and 2, a protective metal piece 14 for a microphone is provided as a part of the outer case 10 in a portion exposed to the outside air, and a wiring board 18 and a frame 16 are incorporated in the outer case 10 to form the wiring board. The heating element 12 is attached to 18 and the heating element 12 and the protective metal fitting 14 for a microphone are connected to each other via a flat heat pipe 20. Further, the abutting portions of the heating element 12 and the microphone protective fitting 14 and the heat pipe 20 are adhered to each other with silicone grease or the like, and even if a shock is applied to the case 10, the adhering portions are secured. Therefore, a spring 15 is provided on the heat receiving portion side of the heat pipe 20 between the heat pipe 20 and the inner wall of the outer case 10, and the heat radiating portion side of the heat pipe 20 is sandwiched and fixed by the microphone protective member 14 and the frame 16.

When a heat pipe 20 having a cylindrical shape instead of a flat shape is used in order to obtain a better heat dissipation effect, the heat receiving portion or the heat radiating portion of the heat pipe 20 is used as described in “Operation”. At least one of them may be formed into a flat plate shape. Further, in the above-described embodiment, since the heat pipe 20 is closely attached to the heating element 12, the heat radiation operation is extremely effective for the heating element 12, but the above-mentioned "Means for solving the problem" is described. As described above, in an electronic device particularly required to be downsized, the heating element 12 is not limited to a specific semiconductor device and may be replaced with another electronic component arranged in the vicinity thereof. 20 is a position that does not affect other components, and is arranged at a position that indirectly promotes heat dissipation of the heat-generating body 12 even if it does not adhere to the heat-generating body (including nearby electronic components) 12 You may.

In the above description, as an example, the heat radiating portion is closely attached to the microphone protective member 14 of the video camera. However, for example, in the case of a portable wireless device, the outer case 10 can be designed as long as it can be closely attached to the speaker protective member. It can be placed in a position where it can be exposed to the outside air without damaging it.

[0018]

[Effects of the Invention] Even if the portable electronic device having the outer case hermetically sealed by the above configuration is continuously used for a long time, the heat of the semiconductor device provided therein is exposed to the outside through the heat pipe 20. The heat is transmitted to the exposed heat sink, and positive heat dissipation becomes possible. As a result, the heat generation of the entire electronic device is suppressed and the user does not feel uneasy.

The heat sink exposed to the outside air may be, for example, a protective metal fitting 14 for a microphone provided as a part of the external case 10 of the electronic device or as a separate component, or the electronic device exterior if it is also used as a protective metal for the speaker. An effective heat dissipation effect can be obtained without changing the shape of the.

When the heat pipe 20 is formed into a cylindrical shape in order to obtain a further excellent heat radiation effect, if at least one of the heat receiving portion and the heat radiating portion of the heat pipe 20 is formed into a flat plate shape, the work such as brazing can be performed. It saves labor and simplifies the manufacturing process.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of the present invention in which a heat pipe is attached to a video camera.

FIG. 2 is a view of the AA cross section of FIG. 1 viewed in the arrow direction.

FIG. 3 is a cross-sectional view of a portion where one end of a cylindrical heat pipe is processed into a flat plate shape and is in close contact with a semiconductor device.

FIG. 4 is a sectional view showing an example of a heat pipe.

FIG. 5 is a sectional view of a portion where a cylindrical heat pipe is brazed to a semiconductor device.

[Explanation of symbols]

 In the drawings, the same reference numerals indicate the same or corresponding parts. 4 Adhesive Material 10 Exterior Case 12 Semiconductor Device (Heating Element) 14 Microphone Protective Metal 16 Frame 20 Heat Pipe 22 Container

Claims (3)

[Scope of utility model registration request] 1. A semiconductor device incorporated in an outer case of an electronic device, and a longitudinal end (heat receiving portion) of a flat or cylindrical heat pipe structure made of a material having good thermal conductivity for the semiconductor device. ) Is closely contacted or indirectly connected, and the other end (heat dissipation part) is joined to a heat sink exposed to the outside air. 2. The cylindrical heat pipe according to claim 1, wherein at least one of the heat receiving portion and the heat radiating portion is processed into a flat plate shape, and these are respectively adhered or indirectly connected to the semiconductor device and the heat sink. A heat dissipation device for portable electronic equipment. 3. The heat dissipation device for a portable electronic device according to claim 1, wherein a protective metal member for a microphone or a speaker of the electronic device is in close contact with a heat dissipation part of the heat pipe and shares a heat sink.