WO2002021609A1

WO2002021609A1 - Thermoelectric cooling module with temperature sensor

Info

Publication number: WO2002021609A1
Application number: PCT/KR2000/001156
Authority: WO
Inventors: Heonphil Ha; Dowbin Hyun; Jaedong Shim
Original assignee: Korea Institute Of Science And Technology
Priority date: 2000-09-07
Filing date: 2000-10-17
Publication date: 2002-03-14
Also published as: KR20020019786A

Abstract

Disclosed is a thermoelectric cooling module with a temperature sensor integrally attached thereto capable of temperature control of an object to be cooled or heated at the same time as prevention of overheating of the thermoelectric cooling module. The thermoelectric cooling module comprises a pair of insulating substrates, thermoelectric elements, a film-type temperature sensor and an insulating thin film layer. The insulating substrates are apart from each other. When electric power is supplied to the thermoelectric cooling module, one insulating substrate is cooled and the other insulating substrate is heated simultaneously. The thermoelectric elements are interposed between the insulating substrates. The film-type temperature sensor is formed on an outer surface of the insulating substrate. The insulating thin film layer is formed on an outer surface of the temperature sensor.

Description

THERMOELECTRIC COOLING MODULE WITH TEMPERATURE SENSOR

Technical Field

The present invention generally relates to a thermoelectric cooling module, and more particularly to a thermoelectric cooling module with a temperature sensor integrally attached thereto.

Background Art

A thermoelectric cooling module is an exchange system between heat and electricity, which can conduct cooling and heating simultaneously by use of the Peltier effect and can realize shift between cooling and heating simply through switchover of its polarity. Since the thermoelectric cooling module is small in volume and can provide rapid and excellent cooling effect, it is being used for a wide scope of applications as a next generation-cooling mode that can substitutes for the existing compressor-cooling mode. Particularly, the thermoelectric cooling module is used in a case of requiring stability of a system in spite of a narrow moving space as in electronic elements, a case of requiring noise elimination, and a case of requiring easy controllability of temperature.

Such a thermoelectric cooling module is fabricated by arranging n-type thermoelectric elements and p-type thermoelectric elements between a pair of insulating substrates made of ceramics such as alumina, beryl lia and aluminum nitride, and by Joining pairs of n-type thermoelectric elements and p-type thermoelectric elements to metal electrodes of the insulating substrates to form p-n couples having series electric circuits. By applying D.C. electric current to the thermoelectric cooling module so that two branched ends of the p-n couples have the positive polarity (+) and the negative polarity (-), respectively, holes within the p-type elements are leaded to the negative poles and electrons within the n-type elements are leaded to the opposite positive poles in accordance with the Peltier effect. At this time, because both of the holes and the electrons are moved to electrodes of two branched ends on a lower side of the thermoelectric cooling module while being accompanied with heat from electrodes of p-n junctions on a upper side of the thermoelectric cooling module, the upper p-n junctions are cooled down and absorb ambient heat whereas two lower branched ends radiate heat. If the electric current flows in the opposite direction, the effect as stated above is fully reversed. Consequently, the thermoelectric cooling module may be used for both cooling and heating, and thus is very suitable for applications requiring temperature control.

This thermoelectric cooling module is used in a state of being attached to an object to be cooled or heated, or in a state of being exposed to a space to be cooled or heated. When the thermoelectric cooling module is used, a heat sink is usually attached to a surface of the thermoelectric cooling module opposing to a surface to be used in order to facilitate heat flow by causing heat exchange. In the cooling mode of the thermoelectric cooling module, for example, heat flows from a cold surface of the thermoelectric cooling module toward the opposite surface and further flows out the thermoelectric cooling module through the heat sink. In addition, the thermoelectric cooling module is used together with a temperature sensor for measuring a target temperature of cooling or heating and for regulating a temperature of the object to be cooled or heated. The temperature sensor also functions to prevent a functional disorder due to overheating of the thermoelectric module from occurring. As the temperature sensors used for these purposes, thermistors, thermocouples, transistor-type thermal sensors and the like may be typically cited.

While the temperature sensor for regulating the temperature of the object to be cooled is attached to the cold surface of the thermoelectric cooling module and the temperature sensor for regulating the temperature of the object to be heated is attached to the hot surface of the thermoelectric cooling module when used in the thermoelectric cooling module, these conventional sensors in use are all bulk-type. When the thermoelectric cooling module is used in the state of being attached to the object to be cooled or heated, however, the bulk-type temperature sensor is interposed between the thermoelectric cooling module and the object to be cooled or heated, and thus there is caused a problem of increasing thermal resistance between the thermoelectric cooling module and the object to be cooled or heated. This problem eventually results in deterioration of performance of the thermoelectric cooling module. Moreover, the conventional temperature sensor in common use has a drawback of being large in volume and so restricting an installation space of the thermoelectric cooling module that exhibits excellent performance in cooling and heating of localized regions. In recent, a thermoelectric cooling module with a thermistor attached thereto has been developed as disclosed in U.S. Patent No. 5,522,225, but this still has a disadvantage that its attachment to the object to be cooled or heated is limited because the thermistor forms a projecting portion having a certain volume, and also has a structural limitation in that the temperature sensor as a separate device ^• is merely assembled to the thermoelectric cooling module. Furthermore, there- is another limitation in that the temperature sensor can perform only any one function, that is, either a function for prevention of overheating of the thermoelectric cooling module or a function for detection of the temperature of the object to be cooled or heated because it is attached only one surface of the thermoelectric cooling module. . _:.. . :■

This conventional thermoelectric cooling module with- the bulk-type temperature sensor attached thereto has shortcomings of structural complexity, low mechanical strength, large size, need for auxiliary, devices and so forth. In order to regulate the temperature of the object to be cooled or- heated more properly, therefore, it requires that more precise and simple temperature sensor be attached to the thermoelectric cooling module. Taking account into this, the inventors have developed a thermoelectric cooling module with a temperature sensor integrally attached thereto according to the present invention.

Disclosure of the invention

Accordingly, the present invention has been made considering the above- stated disadvantages of the conventional thermoelectric cooling module with the temperature sensor attached thereto, and it is an objective of the present invention to provide a thermoelectric cooling module which is easy to be attached an object to be cooled or heated and makes it possible to effectively control a temperature of the object to be cooled or heated by integrally attaching a film- type temperature sensor thereto. It is another objective of the present invention to provide a thermoelectric cooling module capable of measuring a temperature of a cooling or heating region without a separate temperature sensor by directly attaching a temperature sensor thereto. It is another objective of the present invention to provide a thermoelectric cooling module in which it is possible to prevent overheating thereof and simultaneously to control a temperature of an object to be cooled or heated by attaching a film-type temperature sensor having a small volume to each of two substrates of the thermoelectric cooling module. To achieve these objectives, there is provided a thermoelectric cooling module with temperature sensor in accordance with an aspect of the present invention, the thermoelectric cooling module comprising: -

A pair of , insulating substrates being apart from each other, one being cooled and the other being heated simultaneously; thermoelectric elements being interposed between ..the. insulating substrates, and being joined to metal electrodes of the substrates in rows and columns; . - -. a film-type temperature sensor being formed on a outer surface of the insulating substrate; and an insulating thin film layer being formed on an -outer surface of the temperature sensor.

The thermoelectric cooling module according to the present invention is useful for cooling or heating. The film-type temperature sensor may be attached to either a cooling side-insulating substrate or a heat radiating side-insulating substrate, but it is also possible to attach the film-type temperature sensor to both of the cooling side-insulating substrate and the heat radiating side- insulating substrate.

Preferably, the insulating thin film layer is so formed as to fully cover the temperature sensor. Also, it is preferred that the temperature sensor is connected to a power source through inner surfaces of the insulating substrates. Brief Description Of The Drawings

The above objectives, and other features and advantages of the present invention will become more apparent from the following detailed description in conjunction with the drawings, in which:

FIG. 1 is a perspective view of a single-stage thermoelectric cooling module according to the present invention;

FIG. 2 is a perspective view of a multi-stage or cascade thermoelectric cooling module according to the present invention; - FIG. 3. is an exploded perspective view of the thermoelectric cooling module with thermistors attached thereto according to the present invention;

FIG. 4 is an exploded perspective view of the thermoelectric cooling module with thermocouples attached thereto according to the present invention; and -FIG. 5 is a sectional view of the thermoelectric cooling module taken along A-A' line of FIG. 1.

Best Mode for Carrying Out the Invention

Hereinafter, preferred embodiments of a thermoelectric- cooling module with a temperature sensor according to the present invention will be described with reference to the accompanying drawings. In the following description and drawings, the like parts having the same construction and function will be designated by the same numerals. Also, since these embodiments are given only for the purpose of description, it will be apparent by those skilled in the art that the present invention is not limited to these embodiments. FIG. 1 is a perspective view of a single-stage thermoelectric cooling module with a temperature sensor as one embodiment of the present invention, and FIG. 2 is a perspective view of a multi-stage or cascade thermoelectric cooling module with the temperature sensor as another embodiment of the present invention. Basic principles of these two embodiments are the same, and thus the following description will be given with regard to the single-stage thermoelectric cooling module and similar description of the multi-stage thermoelectric cooling module will be omitted. As shown in FIG. 1, the thermoelectric cooling module 10 comprises a pair of insulating substrates 30 disposed parallel to each other at a distance, and p- type semiconductor elements 14 and n-type semiconductor elements 15 as thermoelectric conversion semiconductor elements arranged in rows and columns between the insulating substrates 30. Metal electrodes 13 are formed between the insulating substrates 30 and the semiconductor elements 14, 15. If electric power is supplied to the thermoelectric cooling module via electric wires 12 connected to the metal electrodes 13, one insulating substrate is cooled and the other insulating substrate is heated at the same time. The thermoelectric cooling module- 10 of this type has been commonly used, .-and the present invention can be applied to any types of altered thermoelectric cooling modules, for example, as disclosed in Korean Patent Application Laid-Open Gazette No. 1999-080851.

^• Although ceramic substrates including an alumina (AI₂O3) substrate, a beryllia (BeO) substrate, an aluminum nitride (AIN) substrate, etc. are normally- used as the insulating substrates 30 according to the present invention, there maybe suitably used a metal substrate in which an oxide, layer is formed on its surfaces by anodic oxidization method.

The temperature sensor 20 is attached to each of one cold surface and one- hot., surface of the insulating substrates 30, .that- is, a upside of the upper, insulating substrate and a underside of the lower insulating substrate. Thermistors are commonly used as the temperature sensors 20, but Pt resistor-type thermal sensors and thermocouples can be also used. The temperature sensors 20 are formed as a film-type temperature sensor. This film-type temperature sensor may be formed by means of any kinds of thin film or thick film formation technologies, such as thermal evaporation, electron beam evaporation, sputtering, chemical vapor deposition, ion beam plating, sol-gel process, molecular beam epitaxy (MBE) and screen printing, etc.

FIGs. 3 and 4 show two embodiments of the thermoelectric cooling module with temperature sensor according to the present invention, one embodiment in FIG. 3 being the thermoelectric cooling module with the film-type thermistors attached thereto and the other embodiment in FIG. 4 being the thermoelectric cooling module with the film-type thermocouples attached thereto. In addition to the thermistor and the thermocouple, any other film-type temperature sensor may be attached to the thermoelectric cooling module in the same manner as in the above-mentioned embodiments.

As seen from FIG. 3 or FIG.4, two through holes 21 are formed in opposing sides of the upper insulating substrate and the lower insulating substrate 30, respectively, and inner surfaces of the through holes 21 are coated with conductors or conductor pins are inserted into the through holes 21 so that electric current can flow via the through holes 21. Although FIG. 5 shows a sectional view of the through holes 21 formed in the upper insulating substrate 30 of the thermoelectric cooling module according to the present invention, the sectional structure of FIG. 5 is similarly applied to the through holes 21 in the lower insulating substrate 30. As shown in FIG. 5, the through holes 21 are pierced through the insulating substrates 30 using a laser beam or a drill, and then are coated with the conductors or the conductor pins are inserted into the through holes 21 to permit flowing of electric current to the upside and,- the underside of the insulating substrate 30 via the through holes 21. .-.The temperature sensor 20 is attached to the upside of the insulating substrate 30 while covering upper ends of the conductor pins 23, and electric wires 22 for .the temperature sensor are connected to lower ends of the conductor pins 23 so -that electric current flows from an inner surface of the insulating substrate 30. In such a manner, by connecting outputs of the temperature sensors 20 to a power source coming out insides of both insulating substrates 30, the thermoelectric cooling module can be attached closely to the object to be cooled or heated without the formation of air space acting as thermal resistance. Each outer surface of the so constructed temperature sensors 20 is formed with insulating thin film layer 40 capable of covering the temperature sensor 20 fully. The insulating thin film layer 40 is formed using alumina (AI₂O₃), beryllia (BeO), aluminum nitride (AIN), diamond, or plastic materials such as apton or epoxy resin to prevent electrical contacts of the temperature sensors 20 with the object to be cooled or heated.

The temperature sensor according to the present invention can be provided only on the heat radiating side or the heat absorbing side of the thermoelectric cooling module, and it is also possible to provide the temperature sensors on both sides.

In one preferred embodiment of the present invention as stated above, the temperature sensor is provided on both of the heat radiating side and the heat absorbing side of the thermoelectric cooling module.

The thermoelectric cooling module with the temperature sensor according to the present invention can measure temperatures of both sides of the thermoelectric cooling module by attaching the temperature sensor on both of the insulating substrates of the thermoelectric cooling module. That is, when heat is absorbed into the cold surface facing the object to be cooled and is radiated through the opposite hot surface in the case of using the thermoelectric cooling module for cooling, the temperature sensor attached to the cold surface measures the temperature of the cold surface and the temperature sensor attached to the hot surface measures the temperature of the hot surface. In this way,- it is possible to control the temperature of the object to be cooled by detecting the temper.ature of the cold surface and at the same time to prevent overheating ^• of-_; the thermoelectric cooling module from occurring by measuring the temperature of the hot surface.

The thermoelectric cooling module according to the present invention allows the temperature sensor to be attached to the thermoelectric module in a continuous production line at the fabrication stage of the thermoelectric cooling module. This is out of the existing notion that the thermoelectric cooling module and the temperature sensor are two different devices.

In the thermoelectric cooling module with temperature sensor according to the present invention, the temperature of the object to be cooled or heated can be controlled more effectively because the thermoelectric cooling module is attached closely to the object to be cooled or heated. In addition to the temperature control of the object to be cooled or heated, it is possible to simultaneously prevent impairment of the thermoelectric cooling module due to overheating or overcooling by measuring the temperature of the heat exchange surface and so checking the state of heat exchange, and thermal resistance can be minimized when the thermoelectric cooling module is attached to the object to be cooled or heated owing to the fact that the electric wires for temperature sensing are formed from the insides of the both insulating substrates.

Also, the attachment of the temperature sensor to the thermoelectric cooling module can be realized in a continuous production line at the fabrication stage of the thermoelectric cooling module, thereby reducing production cost.

While the thermoelectric cooling module with a temperature sensor according to the present invention has been illustrated and described under considering a preferred specific embodiment thereof, it will be easily understood by those skilled in the art that the present invention is not limited to the specific embodiment, and various changes, modifications and equivalents may be made without departing from the true scope of the present invention.

Industrial Applicability Therefore, it is expected that the thermoelectric cooling module according to the present invention, which can be fabricated in a single process, be widely used in the whole field of industry.

Claims

What Is Claimed Is:

1. A thermoelectric cooling module with temperature sensor comprising: a pair of insulating substrates being apart from each other, one being cooled and the other being heated simultaneously,^' thermoelectric elements being interposed between the insulating substrates, and being joined to metal electrodes of the substrates in rows and columns; a thin film-type or thick film-type temperature sensor being formed on an outer surface of the insulating substrate; and an insulating thin film layer being formed on an outer surface of the temperature sensor.

2. A thermoelectric cooling module with temperature sensor as recited in claim 1, wherein the temperature sensor is formed on both of a cooling side- insulating substrate and a heat radiating side-insulating substrate.

3. A thermoelectric cooling module with temperature sensor as recited in claim 1, wherein the temperature sensor is formed only on the cooling side- insulating substrate

4. A thermoelectric cooling module with temperature sensor as recited in claim 1, wherein the temperature sensor is formed only on the heat radiating side- insulating substrate.

5. A thermoelectric cooling module with temperature sensor as recited in claim 1, wherein the insulating thin film layer is so formed as to fully cover the temperature sensor.

6. A thermoelectric cooling module with temperature sensor as recited in claims 1 to 5, wherein the temperature sensor is connected to a power source through an inner surface of the insulating substrate.