JPS63257282A - Electronic cooler - Google Patents

Abstract

PURPOSE:To increase a temperature difference between a cooling face and a heat sink by a method wherein two or more Ettingshausen elements connected mutually in series are arranged on the identical heat sink and these elements are connected thermally so that these elements constitute a number of stages. CONSTITUTION:A first element part 2 which is composed of a first heat sink 1 made of Al2O3 and cascade-shaped Bi single.crystal Ettingshausen elements E1, E2, E3 arranged on this heat sink and a second element part 4 which is similarly composed of a second heat sink 3 made of Al2O3 and a cascade-shaped Bi single-crystal Ettingshausen element E4 arranged on the that sink are laminated in such a way that a cooling face of the second Ettingshausen elements E1, E2, E3 for the first element part 2 comes into contact with the second heat sink 3 for the second element part 4. Magnets 5 are arranged on both sides of this laminate. An electric current is made to flow through individual Ettingshausen elements from a power supply; a temperature on the cooling face of the Ettingshausen element 4 for the second element part is lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic cooler, and particularly to an electronic cooler that utilizes the Etchingshausen effect. [Prior art and its problems] Research on elements that can obtain excellent characteristics only at extremely low temperatures, such as infrared detectors and Josephson elements, has been widely conducted. being done.

One of them is an element called an etchingshausen device that utilizes the etchingshausen effect.

The Etchingshausen effect is caused by passing a current Ix through a metal or semiconductor in the X direction, and increasing the magnetic field density B in the Z direction perpendicular to it.
This refers to the effect that when a magnetic field Bz is applied to prevent either heat flow or current from flowing in the Y direction, a temperature gradient occurs in that direction.

In other words, as shown in the principle diagram in Figure 5, when a current Ix is passed in the X direction through a material in which electrons and holes coexist, and a magnetic field Bz is applied in the Z direction, the Lorentz force causes electrons and holes to flow together in the Y direction. curved to

Electrons and holes conduct in the X direction because pairs are repeatedly generated and recombined, and the activation energy when generating pairs is released again during recombination.

However, while electrons and holes are pairing and recombining, they are also displaced in the Y direction by the Lorentz force, so
This means that activation energy is carried in the Y direction, and Y
A temperature difference occurs in the direction.

The coefficient of performance Z of the etchingshausen element is expressed as xy. Here, α is the electromotive force in the X direction relative to the temperature difference in the Y direction, 6 is the electric conductivity in the X direction, and K
is the thermal conductivity in the Y direction.

In addition, a rectangular element (lectangylar element) shown in FIG.
), where the temperature on the heat sink side is T and the temperature on the cooling surface side is T, the cooling temperature ΔT-Th h
It is known that T o is determined by the following equation.

(ΔT) −−Z −T 2
(2) max feet, ) xy
b That is, it is determined by the coefficient of performance determined by the material and the temperature on the heat sink side.

Furthermore, a form factor is added to this.

By the way, as shown in FIG. 6(a), an Etchingshausen element made of semimetal or semiconductor with a Fuji-shaped cross section, called a cascade type, with a narrow width on the cooling surface side and a curved side surface, has been used as a high-efficiency element. Are known.

Assuming that the outline l of this side surface has a shape expressed by the following equation (3), γ (where b is the height, that is, the distance between the heat sink side surface and the cooling surface, and γ is the shape factor ) The cooling temperature (ΔT ) of this cascade-type etchingshausen element is
is expressed as ff1aX eXp shown in the following equation (4).

Therefore, the performance coefficient Z determined by this shape factor γ and the material
By setting xy to optimal values, a highly efficient etching Shausen element can be obtained.

A magnetic field is applied to the Etchingshausen element selected in this way by a magnet 5 as shown in FIG.
An electronic cooler is formed by flowing x, but the current value must be selected to provide the optimum current density for operating the device. Therefore, in order to obtain a large temperature difference ΔT, the device must be large in size and a large current must flow, resulting in a problem that the operating power supply becomes large-scale.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an electronic cooler with high cooling capacity without requiring a large current power source.

[Means for solving problems]

Therefore, in the present invention, in an electronic cooler that includes a magnetic field forming means and an etchingshausen element and that obtains a cooling surface by the movement of heat in a direction perpendicular to the magnetic field and the current direction, the electronic cooler is configured such that the direction of the current is the same. A plurality of Etchingshausen elements connected in series are arranged in parallel on the same heat sink, and a plurality of element parts are stacked in multiple stages and are in thermal contact with each cooling surface of the first element part. The heat sink of the second element part is disposed in the second element part, and the number of elements of the etched Shausen element of the second element part is the same as that of the first element part.
The number of elements is made smaller than the number of elements in the element section.

[Effect]

In other words, a plurality of Etchingshausen elements connected in series are arranged side by side on the same heat sink, and they are brought into thermal contact in multiple stages, so cooling can be achieved without increasing the current. The temperature difference ΔT between the surface and the heat sink can be increased.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing an electronic cooler according to an embodiment of the present invention.

As shown in FIG. 1 and a cross-sectional view in FIG. 2, this electronic cooler consists of a first heat sink 1 made of alumina ceramic (A12O) and a cascade-shaped bismuth (Bi) heat sink arranged on top of the first heat sink 1. ) Etchingshausen elements El, E2.) made of single crystals. E3, a second heat sink 3 made of alumina ceramic, and an etchingshausen element E4 made of a cascade-shaped bismuth (Bi) single crystal disposed thereon. The second element portion is the etchingshausen element El of the first element portion 2.

E2. The 20th heat sink 3 of the second element section 4 is laminated so as to be in contact with the cooling surface of E3, and the magnet 5 is arranged so that the side S of the laminated body forms a magnetic field Bz of 8 kilogauss. This magnetic field Bz
In each etchingshausen element El, E2. E3
．． A current lx is applied to E4 from a power source (not shown) to lower the temperature of the cooling surface of the etchingshausen element E4 in the second element part, thereby creating a temperature difference Δ with respect to the first heat sink 1.
It is designed to obtain a low temperature of T and is used for cooling substances.

Here, all four etchingshausen elements E1 to E4 have the same structure, and as shown in FIG. 3, the width on the cooling surface side is C1 - 0.027 mark, and the width on the heating surface side is C2 = 0.027.
18cm, height b-0,26cm, length 3.00cm
It is made of a cascade-shaped bismuth single crystal, and electrodes AI and A2 are formed on both end faces, and the first and second electrodes are formed on both end faces.
At the same time as it is pasted on the heat sink of
-E3 and E4 are connected in series so that current flows through each element in sequence and in the same direction.

The heat sink temperature is 156° in a vacuum of 105 Torr.
Current when flowing current through this electronic cooler while keeping it at K (
FIG. 4(a) shows the relationship between the cooling temperature (horizontal axis) and the temperature difference ΔT (vertical axis) between the first heat sink and the cooling surface of the etchingshausen element E4.

From this figure, it can be seen that, for example, in order to obtain a cooling temperature of ΔT-25°, an extremely small current of 5 A is required, and the device has a high cooling capacity.

For comparison, the relationship between the current and cooling temperature of the conventional electronic cooler shown in FIG. 6 is shown in FIG. 4(b).

Here, this etchingshausen element has a width C on the cooling surface side.
l-0.054cm, width on heating surface side C2-0.37cm
, height b-0,522 cm, and length 3.00 am.

As is clear from the comparison between FIG. 3 and FIG. 5, the etchingshausen elements 01 to C4 of the embodiment of the present invention correspond to the etchingshausen elements 01 to C4 of the embodiment of the present invention, which are obtained by dividing the conventional etchingshausen element into four parts.

From a comparison between FIG. 4(a) and FIG. 4(b), it can be seen that according to the electronic cooler according to the embodiment of the present invention, approximately 1/4 to 115 times the current is required to obtain the same cooling temperature. .

In the embodiment, the element section has a two-stage configuration, but it is not limited to two stages, and can be appropriately selected from three stages, four stages, etc.

In addition, in the example, as an etchingshausen element,
Although a bismuth single crystal molded into a cascade shape was used, the material is not limited to this example, and materials include bismuth-antimony (Bi-Sb) alloy, mercury telluride (H
gTe), mercury selenide (HgSe), tin (S n )
, magnesium lead (Hg2Pb), graphite, cadmium arsenide (Cd3As2), etc., which have equal hole and electron concentrations, both have high mobility, and have low heat conduction due to lattice vibration.Intrinsic semiconductors and semimetals. It can be selected as appropriate.

Furthermore, in the example, the magnetic field was formed using a magnet block placed outside the stack of elements, but this can be modified as appropriate, such as by arranging a magnet between each element or using an electromagnet. It is.

[Effects of the Invention] As explained above, according to the electronic cooler of the present invention, a plurality of etchingshausen elements are connected in series, and the number of elements decreases toward the cooling surface, so that good thermal conductivity is achieved. Since they are stacked in multiple stages with different substrates interposed in between, a high cooling capacity can be obtained with a small Kh'A.

[Brief explanation of drawings]

FIG. 1 is an overall schematic diagram of an electronic cooler according to an embodiment of the present invention;
FIG. 2 is a cross-sectional view of the element part of the electronic cooler, FIG. 3 is a diagram showing an etchingshausen element used in the electronic cooler, and FIGS. 4(a) and (b) are respectively FIG. 5 is an explanatory diagram of the Etchingshausen effect, and FIGS. 6(a) and (b) are cascade-type Etchingshausen elements and It is a figure which shows the conventional electronic cooler using this. 1... First heat sink, 2... First element section,
3... Second heat sink, 4...': B2 element section, 5... Magnet, E1 to E4... Etchingshausen element, AI, A2... Electrode. □1. j' Fig. 2 Δ R Fig. 3 wl (AMP) Fig. 4 (α) lt child (AMP) Fig. 4 (b)

Claims (1)

[Claims] A substrate with good thermal conductivity as a heat sink in an electronic cooler using an etchingshausen element that utilizes a temperature gradient generated by applying a magnetic field perpendicular to the direction of current; A cooling surface side of each element section, comprising a multi-stage element section including at least one etchingshausen element arranged in parallel, and a magnetic field forming means for forming a magnetic field for these etchingshausen elements, and a cooling surface side of each element section. stacking a plurality of stages of the element parts so that the heat sink side of the next element part is in thermal contact with the element part, and the number of elements in the element part brought into contact with the cooling surface side is smaller than the number of elements in the element part; Furthermore, this electronic cooler is characterized in that each element is connected in series.