JP2007109819A - Portable electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a portable electronic apparatus which is controlled in size, can be manufactured easily, ensures effective thermo-electric conversion, and is capable of extending the operating period of a battery. <P>SOLUTION: A thermo-electric converter 3 is provided including thin-film heat absorber 33 and heat radiator 34 which are formed almost on the same plane. This thermo-electric converter 3 is arranged on the upper front surface of a semiconductor component 60, and an electrical power converted with the thermo-electric converter 3 is supplied for charging the battery or for operation of a portable electronic apparatus. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a portable electronic device, and more particularly to a technique for extending operating time in a portable electronic device such as a mobile phone or a mobile PC that operates on a battery.

In general, portable electronic devices such as mobile phones, mobile PCs, portable game machines, and PDAs (Personal Digital Assistants) are required to be small and have high performance. With regard to higher performance, the heat density of semiconductor elements has increased in exchange for higher integration of semiconductor elements, higher frequency of clock signals, etc., resulting in an increase in the amount of heat generated by semiconductor elements and operation. Not only does it become unstable, but it also causes a problem of deterioration of electronic components due to heat.
In addition, with the increase in definition and size of liquid crystal screens and the increase in brightness of backlights, there has been a problem of not only an increase in heat generation but also an increase in power consumption.
In addition, due to the demand for miniaturization, the size and shape of the built-in battery are restricted, so that a battery with a very large capacity cannot be mounted, and there is also a demand for extending the life of the power supply (increasing continuous operation time). Moreover, in the current portable electronic devices, not only normal functions (for example, standby reception and call, transmission / reception of emails for mobile phones, information processing for mobile PCs) but also diversification of usage modes such as video and music appreciation, portable The problem is that the power supply capacity of electronic equipment is not a satisfactory life for its usage.
In order to solve these problems, the temperature rise of the semiconductor element is suppressed by a cooling structure using heat radiation fins, a cooling fan, etc., against the temperature rise of the element. In addition, with respect to the problem of the life of the power supply, a method such as mounting a second power supply and extending the operation time has been taken.
However, in these methods, for example, the use of heat radiation fins and cooling fans will increase the volume and weight of the device, and also increase the volume and weight for mounting the second power supply, The result is a reduction in the original portability advantage.
As for the extension of the life of the power supply, the battery itself has been improved, and while it has been reduced in size, increased in capacity, and increased in output voltage, the portable electronic device is configured so that it can be charged from other than the charger while it is being carried. There is also equipment. For example, in a solar cell phone set described in Patent Document 1, a solar cell is attached to the casing of a mobile phone, and in a bright ambient environment, the power battery is charged with the power generated by the solar cell. The standby time can be extended. However, there is a drawback that power generation is not possible in dark places.

In addition, a method of charging a secondary battery by installing a thermoelectric conversion device outside the portable terminal device, heating the device, converting this heat into electricity, instead of power generation by light has been proposed. (For example, refer to Patent Document 2). According to this method, when using a mobile terminal device, it is heated at body temperature, and when it is carried, for example, if it is carried in a pocket, it can be charged due to the temperature difference between the outside air and body temperature, and in an emergency, a lighter It can also be charged using an external heat source such as fire.
There is also a mobile phone device that includes a thermoelectromotive force conversion element such as a Peltier element inside the exterior body, charges an electromotive force generated by heat generated inside the device to a secondary battery, and supplies the rechargeable battery for operation of the wireless transmission / reception means. (For example, refer to Patent Document 3). According to this prior art, the secondary battery can be charged even in a dark place by the electric power generated by the heat generated inside the mobile phone device. For this reason, it can be used as a power source for standby reception, can operate for a long time, and can cool the inside of the apparatus.
In addition, the device includes a secondary battery, a semiconductor chip, a package for mounting the semiconductor chip, a printed circuit board on which the package is mounted, and a thermoelectric conversion device. By converting this heat into electricity, the secondary battery is charged. An electronic device has also been proposed in which the heat of a semiconductor package is cooled by a thermoelectric conversion device while the usage time of the electronic device can be extended (for example, see Patent Document 4).
In addition, a method has been proposed in which heat generated in a semiconductor chip is converted into electric energy by a thermoelectric conversion device, thereby driving a small fan to cool the semiconductor chip or the like (for example, see Patent Document 5). According to this method, since the heat energy generated by the heat generated by the semiconductor chip is converted into electric energy and used as electric power for the small fan, the original battery is not consumed even if the small fan is driven.
Japanese Utility Model Publication No. 4-110040 JP 2002-291166 A Japanese Patent Laid-Open No. 9-186753 Japanese Patent No. 3219055 Japanese Patent Laid-Open No. 9-92761

However, in the prior art of Patent Document 2, if the temperature difference between the body temperature at the time of use, for example, the hand, and the inside is small, charging is not sufficient, and a heat source such as a lighter must be carried around at all times. There is a problem of not becoming.
Moreover, in the prior arts of Patent Documents 3, 4 and 5 having a thermoelectric conversion device inside the casing, the temperature difference between the heat absorption part and the heat dissipation part important for thermoelectric conversion cannot be obtained sufficiently, and the apparatus cannot be made small. There is a problem. In particular, in Patent Document 4, the front surface and the back surface of the thermoelectric conversion device are a heat absorption portion and a heat dissipation portion, respectively, and the thermoelectric conversion device is disposed between a package on which a semiconductor chip is mounted and a printed board on which the package is mounted, In addition, since the semiconductor chip is connected to the wiring of the printed circuit board by leads, the heat of the semiconductor chip is transferred to the printed circuit board through the leads, and as a result, a sufficient temperature difference can be obtained between the semiconductor package and the printed circuit board. In addition, there is a problem that the printed circuit board is heated by heat from other elements mounted on the same printed circuit board. Furthermore, since the thermoelectric conversion device is configured by sandwiching the thermoelectric semiconductor between the element plates, the volume of the thermoelectric conversion device is large, and there is a problem in reducing the size and weight of the electronic device.
Furthermore, since the thermoelectric conversion device is inserted between the package on which the semiconductor chip is mounted and the printed circuit board on which the package is mounted, the semiconductor package or the like must be lifted from the printed circuit board by the thickness of the thermoelectric conversion device and mounted and soldered. In addition, it takes time and effort to insert and fix the thermoelectric converter.
That is, in the prior art of Patent Document 4, the thermoelectric conversion device is arranged between the component and the printed circuit board. Therefore, when the thermoelectric conversion device is thinned, the heat absorption side component and the heat radiation side printed circuit board are disposed. Not only can a sufficient temperature difference be obtained, but it becomes difficult to insert the thermoelectric conversion device, and if the thermoelectric conversion device is made thick, this problem is alleviated, but there is a problem that the miniaturization of the electronic device is impaired.
The present invention has been made in consideration of the above-described circumstances, and is a portable electronic device that can suppress the enlargement of the device, can be easily manufactured, can efficiently perform thermoelectric conversion, and can extend the operation time of the battery. The purpose is to provide equipment.

In order to solve the above-mentioned problems, the invention described in claim 1 is a portable electronic device having a printed circuit board including a semiconductor component and operating with a built-in battery, comprising a thin-film heat absorption part and a heat radiation part. A thermoelectric conversion device formed on substantially the same plane, the thermoelectric conversion device is disposed on an upper surface of the semiconductor component, and the electric power converted by the thermoelectric conversion device is used for charging the battery or for a predetermined portable electronic device It is characterized in that it is supplied as a power source for function operation.
According to a second aspect of the present invention, in the portable electronic device according to the first aspect, the heat absorption portion of the thermoelectric conversion device is a heat generation portion of the semiconductor component, and the heat dissipation portion of the thermoelectric conversion device is a portion of the semiconductor component. It arrange | positions so that it may become the outer side of an edge part.
According to a third aspect of the present invention, in the portable electronic device according to the first or second aspect, the thermoelectric conversion device is disposed on the semiconductor component and fixed to the printed circuit board via a spacer. And
According to a fourth aspect of the present invention, in the portable electronic device according to the first or second aspect, the thermoelectric conversion device is fixed on the semiconductor component with an adhesive.
According to a fifth aspect of the present invention, in the portable electronic device according to the first or second aspect, the thermoelectric conversion device is fixed on the semiconductor component with a double-sided adhesive tape.
According to a sixth aspect of the present invention, in the portable electronic device according to any one of the first to fifth aspects, the semiconductor component is a semiconductor integrated circuit.
The invention according to claim 7 is a portable electronic device having a display device and operating with a built-in battery, wherein the thin-film heat absorbing portion and the heat radiating portion are formed on substantially the same plane. The thermoelectric conversion device is arranged on the back surface of the display device, and the electric power converted by the thermoelectric conversion device is supplied for charging the battery or operating power for a predetermined function of the portable electronic device. It is characterized by that.
The invention according to claim 8 is the portable electronic device according to claim 7, wherein the heat absorption part of the thermoelectric conversion device is the heat generation part of the display device, and the heat dissipation part of the thermoelectric conversion device is the display device. It arrange | positions so that it may become the outer side of an edge part.
The invention according to claim 9 is a portable electronic device that operates with a built-in battery, comprising a thermoelectric conversion device in which a thin-film heat absorption part and a heat radiation part are formed on substantially the same plane, and the thermoelectric conversion A device is arranged on the surface of the battery, and the power converted by the thermoelectric converter is supplied as a power source for charging the battery or operating a predetermined function of a portable electronic device.
The invention according to claim 10 is the portable electronic device according to claim 9, wherein the heat absorption part of the thermoelectric conversion device is the heat generation part of the battery, and the heat dissipation part of the thermoelectric conversion device is the edge of the battery. It arrange | positions so that it may become the outer side of a part.

  According to the present invention, the increase in the size of the device can be suppressed as much as possible, the heat generated inside the device during operation can be efficiently converted to electricity, the device can be operated with the obtained electricity, and the built-in battery can be charged. Therefore, it is possible to extend the operation time by the battery of the portable electronic device.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the description of the present embodiment, a mobile phone is described as an example of the portable electronic device, but the present invention can be similarly applied to a portable electronic device such as a PDA, a mobile PC, or a portable game machine.
FIG. 1 is an external perspective view of a portable electronic device according to an embodiment of the present invention. As shown in the figure, on the upper part of the main body, a camera 13 for photographing, a receiver 14 (speaker) for performing voice communication, an antenna 16 for transmitting and receiving radio waves, information from a connected website, and transmission / reception A liquid crystal display unit 5 for displaying a mail document, an image taken by the camera 13, and the like are attached.
Also, on the lower part of the main body, there is an operation unit 17 composed of a plurality of buttons for performing operations such as a power on (ON) / off (OFF) button, input of letters, numbers, symbols, etc., menu selection, and voice communication. The transmitter 15 (microphone) etc. to perform is provided.
In addition, inside the housing, a printed circuit board 7 that holds various processing circuits composed of semiconductor elements and the like, a thermoelectric conversion device 3 that converts heat generated from semiconductor elements of various circuits formed on the printed circuit board 7 into electricity, A rechargeable battery (not shown) or the like serving as a power source is accommodated.
2 is a schematic perspective view of the interior of the portable electronic device shown in FIG.
As shown in the figure, on the printed circuit board 7, there are provided a circuit composed of a semiconductor element 60 for performing sound processing, image processing, various controls, a driving circuit 6 for driving the liquid crystal display unit 5, and an antenna 16 (not shown). A wireless circuit for processing radio waves is formed. Each circuit does not need to be formed on one printed board 7 as in this example, and may be configured using a plurality of printed boards.

FIG. 3 is a diagram illustrating the arrangement of the thermoelectric conversion device 3 in the portable electronic device of the present invention.
Although details of the thermoelectric conversion device 3 will be described later, the thermoelectric conversion element used in the thermoelectric conversion device 3 generates power according to the temperature difference, and the side that keeps the temperature high is the heat absorption part, and conversely the temperature The side that keeps low is referred to as the heat dissipation part.
Since the semiconductor element 60 constituting the various circuits generates heat during operation, the thin-film thermoelectric conversion device 3 includes a heat absorption part of the thermoelectric conversion device 3 in the heat generation part on the semiconductor element 60 and a part away from the heat generation part. Is installed to be a heat dissipation part. With such an arrangement, the temperature difference between the heat absorption side and the heat dissipation side of the thermoelectric conversion device 3 can be increased, and the heat generated during the operation of the semiconductor element 60 can be efficiently converted into electricity. In addition, since the thin-film thermoelectric conversion device 3 is brought into contact with the upper portion of the semiconductor element 60, the printed board may be manufactured by the same method as the conventional method. Can be avoided.
Since the electric power generated by the thermoelectric conversion device 3 can be connected to a battery (not shown) and charged (charged), unlike a solar battery, the battery can be easily fully charged even in a dark place, and is small and portable. Is also excellent. Moreover, you may utilize the electromotive force of the thermoelectric conversion apparatus 3 as a power supply of communication means, such as standby reception which is not shown in figure.
FIG. 4 is a diagram illustrating a state in which the thermoelectric conversion device 3 is disposed on the semiconductor element 60. The thermoelectric conversion device 3 is formed in a thin film shape, and is fixed to the printed circuit board 7 with spacers 8 and screws 9 so as to be in close contact with an upper package of a semiconductor element 60 such as an integrated circuit on the printed circuit board 7. The thermoelectric conversion device 3 is arranged such that the portion of the semiconductor element 60 that generates a large amount of heat near the center of the upper package becomes the heat absorbing portion 33 and the portion that protrudes from the end or outer periphery becomes the heat radiating portion 34. By making the spacer 8 a good heat conductive material such as a metal, heat can be transmitted well to the printed circuit board 7 and the temperature difference between the heat absorbing portion 33 and the heat radiating portion 34 can be increased. Further, as shown in FIG. 5, by providing the grooves 8a at a predetermined pitch on the outer peripheral surface of the spacer 8, the surface area can be increased, and the heat radiation around the heat radiating portion 34 is promoted.
Further, as shown in the modification of FIG. 6, the thermoelectric conversion device 3 may be directly bonded to the surface of the semiconductor element 60 using the heat conductive adhesive 18, and the heat conduction is performed instead of the heat conductive adhesive 18. You may affix with an adhesive double-sided adhesive tape. By doing so, an increase in manufacturing costs can be suppressed.

Next, a thermoelectric conversion device used for the portable electronic device according to the present invention will be described.
7 and 8 are diagrams illustrating the configuration of the thermoelectric conversion device 3. FIG. In FIG. 7, the thermoelectric conversion device 3 connects a plurality of thin film P-type semiconductors 31 and N-type semiconductors 32 with positive and negative electrodes to a substrate 37 anodized with an insulating plate-like alumina ceramic or aluminum. A thermoelectric semiconductor element is formed, and each thin-film thermoelectric semiconductor element is sandwiched between plates such as alumina ceramics (not shown).
As a material of the P-type semiconductor 31 and the N-type semiconductor 32, for example, a Bi-Te alloy processed into a thin film is used. Specifically, in the outer dimensions, the thickness is about 0.3 mm, the width is 2 mm, and the length is about 10 mm, and the thickness (the height of the element) is the smallest. If formed, a smaller and higher performance thermoelectric conversion device is obtained.
The P-type semiconductor 31 and the N-type semiconductor 32 are electrically connected by a metal wiring 35, and this portion serves as a heat absorbing portion 33, and the other of the P-type semiconductor 31 and the N-type semiconductor 32 serves as a heat radiating portion 34. A conversion element 30 is configured. A plurality of sets of thermoelectric conversion elements 30 are connected in series, and power extraction electrodes 36 are provided by wiring with aluminum or copper at both ends. And it may be used for charging the battery 40 as shown in the figure, or may be used as a power source for communication means or the like.
In FIG. 7, the semiconductor element 60 serving as a heat source is a PGA (Pin Grid Array) type integrated circuit having a shape close to a square, so that the heat radiating portion 34 of the thermoelectric conversion element 30 is outside each end of the semiconductor element 60. To place.
On the other hand, in the modification shown in FIG. 8, the semiconductor element 60 serving as a heat source is an elongated rectangular DIP (Dual Inline Package) type integrated circuit, so that the heat radiating portion 34 is outside the opposite end portions in the longitudinal direction. To place.
In this embodiment, all outputs of the thermoelectric conversion elements 30 installed on the semiconductor element 60 are connected in series, and both ends thereof are connected to the battery 40. As the battery, a secondary battery such as a lithium ion secondary battery, a metal lithium secondary battery, an alkaline storage battery, a lead acid battery, a lithium polymer battery, or a storage battery such as a capacitor may be used. By attaching these batteries and charging (storage) circuit to a portable electronic device, it is possible to store the electric power generated by using waste heat. Therefore, it is possible to extend the operation time by the battery.
In addition, although the material of the P-type semiconductor 31 and the N-type semiconductor 32 was shown in the example of the Bi-Te type alloy, it is not limited to these materials, for example, Fe-Si having a high temperature range depending on the environmental temperature. A thermoelectric semiconductor obtained by processing a metal alloy or a metal oxide alloy into a thin film may be used.
Further, the material of the metal wiring 35 may be any conductive material such as gold, silver, chromium, aluminum, nickel, copper, and the like having a high thermal conductivity. In addition to these single metals, a compound containing silicon, nickel, An alloy containing chromium or the like may be used.

Next, an example in which the thermoelectric conversion device 3 is used for the liquid crystal display unit 5 of the portable electronic device according to the present invention will be described.
FIG. 9 is a diagram illustrating an example in which the thermoelectric conversion device 3 is used in the liquid crystal display unit 5.
A general liquid crystal display device is provided with a backlight, and the light from the backlight enters the eyes of the user through a liquid crystal and a color filter. At this time, the liquid crystal element serves as a light switch, and color display is performed by turning on / off the liquid crystal elements corresponding to the color filters (red, green, and blue). Although the backlight generates less heat, heat accumulates not only in the backlight but also in the reflector and the liquid crystal element when used for a long time. Of course, heat is also generated from an integrated circuit or the like of a drive circuit that drives the liquid crystal device. In this case, thermoelectric conversion may be performed by the method described with reference to FIGS.
In FIG. 9, the heat absorption part 33 of the thermoelectric conversion device 3 including a plurality of thin-film thermoelectric conversion elements 30 is located on the back surface of the liquid crystal display part 5, and the heat radiation part 34 is located away from the liquid crystal display part 5. Install as follows. By carrying out like this, the heat | fever of the liquid crystal display part 5 can be thermoelectrically converted, and it can generate electric power, and heat can be moved to the housing | casing part which is not shown in figure.
Moreover, the electric power obtained in this way can be used for the operation of the liquid crystal display unit 5 or for charging the rechargeable battery 40. As a result, long-time standby reception and long-time communication and data processing become possible.

Next, an example in which the thermoelectric conversion device 3 is used for the battery 40 of the portable electronic device according to the present invention will be described.
FIG. 10 is a diagram illustrating an example in which the thermoelectric conversion device 3 is used for the battery 40. In the figure, the thermoelectric conversion device 3 is disposed on the surface of a battery 40 which is a built-in power source of a portable electronic device such as a cellular phone. The thermoelectric conversion device 3 generates power with heat generated when the battery 40 supplies power, and the generated power is sent to the charging circuit 43 via the power extraction electrode 36. The charging circuit 43 includes a current control circuit 44, a voltage control circuit 45, and a charging control circuit 46, and charges the battery 40 with the electric power obtained by the thermoelectric conversion device 3.
Although two batteries 40 are shown in the figure, one battery is actually provided below the thermoelectric conversion device 3. That is, the heat absorption part 33 of the thin-film thermoelectric conversion device 3 is installed on the surface of the battery 40, and the heat dissipation part 34 is installed at a position removed from the battery 40, and the heat of the battery 40 is thermoelectrically converted to a housing (not shown). Move outside.
With such a configuration, heat generated when the battery 40 is discharged can be efficiently converted into electricity and charged to the battery 40. The electromotive force of the thermoelectric conversion device 3 can also be used as a drive power source for portable electronic devices.

1 is an external perspective view of a portable electronic device according to an embodiment of the present invention. It is a schematic perspective view inside the portable electronic device shown in FIG. It is a figure explaining arrangement | positioning of the thermoelectric conversion apparatus in the portable electronic device of this invention. It is a figure which shows the state which has arrange | positioned the thermoelectric conversion apparatus on the semiconductor element. It is a figure which shows the other Example of a spacer. It is a figure which shows the state which has arrange | positioned the thermoelectric conversion apparatus on the semiconductor element. It is a figure explaining the structure of a thermoelectric conversion apparatus. It is a figure explaining the structure of a thermoelectric conversion apparatus. It is a figure which shows the example which has arrange | positioned the thermoelectric conversion apparatus in the liquid crystal display part. It is a figure which shows the example which has arrange | positioned the thermoelectric conversion apparatus on the battery surface.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 3 ... Thermoelectric conversion device, 5 ... Liquid crystal display part, 6 ... Drive circuit, 7 ... Printed circuit board, 8 ... Spacer, 9 ... Screw, 13 ... Camera, 14 ... Receiver part, 15 ... Transmitter part, 16 ... Antenna, 17 DESCRIPTION OF SYMBOLS ... Operation part, 18 ... Thermally conductive adhesive, 30 ... Thermoelectric conversion element, 31 ... P-type semiconductor, 32 ... N-type semiconductor, 33 ... Heat absorption part, 34 ... Heat dissipation part, 35 ... Metal wiring, 36 ... Power extraction electrode , 37 ... substrate, 40 ... battery, 43 ... charging circuit, 44 ... current control circuit, 45 ... voltage control circuit, 46 ... charge control circuit, 60 ... semiconductor element

Claims (10)

  A portable electronic device having a printed circuit board including a semiconductor component and operated by a built-in battery, comprising a thermoelectric conversion device in which a thin-film heat absorption portion and a heat dissipation portion are arranged on substantially the same plane, and the thermoelectric conversion device Is arranged close to the upper surface of the semiconductor component, and the electric power converted by the thermoelectric converter is supplied for charging the battery or operating power for a predetermined function of the portable electronic device. Portable electronic device.   2. The portable device according to claim 1, wherein the heat absorption part of the thermoelectric conversion device is arranged close to the heat generation part of the semiconductor component, and the heat dissipation part of the thermoelectric conversion device is arranged outside the edge of the semiconductor component. Type electronic equipment.   3. The portable electronic device according to claim 1, wherein the thermoelectric conversion device is disposed on the semiconductor component and fixed to the printed board via a spacer.   3. The portable electronic device according to claim 1, wherein the thermoelectric conversion device is fixed on the semiconductor component with an adhesive.   The portable electronic device according to claim 1 or 2, wherein the thermoelectric conversion device is fixed on the semiconductor component with a double-sided adhesive tape.   The portable electronic device according to claim 1, wherein the semiconductor component is a semiconductor integrated circuit.   A portable electronic device having a display device and operating with a built-in battery, comprising a thermoelectric conversion device in which a thin-film heat absorption portion and a heat dissipation portion are formed on substantially the same plane, and the thermoelectric conversion device is the display device A portable electronic device characterized in that it is disposed on the back surface of the battery and the electric power converted by the thermoelectric conversion device is supplied as a power source for charging the battery or operating a predetermined function of the portable electronic device.   8. The mobile phone according to claim 7, wherein the heat absorption part of the thermoelectric conversion device is arranged at a heat generation part of the display device, and the heat radiation part of the thermoelectric conversion device is arranged outside an edge of the display device. Type electronic equipment.   A portable electronic device that operates with a built-in battery, comprising a thermoelectric conversion device in which a thin-film heat absorption part and a heat dissipation part are formed on substantially the same plane, the thermoelectric conversion device being arranged on the surface of the battery, A portable electronic device characterized in that power converted by a thermoelectric converter is supplied as a power source for charging the battery or operating a predetermined function of the portable electronic device.   10. The portable electronic device according to claim 9, wherein the heat absorption part of the thermoelectric conversion device is disposed at a heat generation part of the battery, and the heat radiation part of the thermoelectric conversion device is disposed outside an edge of the battery. machine.

Images