JP4575106B2 - Thermoelectric converter - Google Patents

Description

  The present invention relates to a thermoelectric conversion device including a thermoelectric conversion element that generates power by cooling, heating, and a temperature difference.

  The thermoelectric conversion element is manufactured by joining a P-type thermoelectric material and an N-type thermoelectric material via a metal to form a PN junction. This thermoelectric conversion element produces a so-called Peltier effect in which current flows through the element to cool in one joint pair and heat is generated in the other joint pair. This thermoelectric conversion element is used as a cooling device or precision temperature control device using this effect. ing.

  In general, a thermoelectric conversion element is composed of a plurality of columnar P-type and N-type thermoelectric material pieces (hereinafter referred to as thermoelectric elements) called thermoelectric elements and two substrates provided with metal electrodes for joining them. . In a state where the P-type and N-type thermoelectric elements are sandwiched between two substrates, one end surface is fixed to the metal electrode of one substrate, and the other end surface is fixed to the metal electrode of the other substrate. Thus, a PN junction pair is formed and the PN junction pairs are connected in series.

  In order to supply or take out electric power to or from the thermoelectric conversion element having such a structure, a lead wire made of a single core or a stranded wire is attached to one substrate constituting the thermoelectric conversion element by solder or the like. It has been. For example, Patent Document 1 describes such an example.

  On the other hand, digital cameras and video cameras use solid-state image sensors using semiconductors such as CCD image sensors and CMOS image sensors for image sensing. Image sensors using these semiconductors darken as temperature rises. The current increases. This increase in dark current results in a decrease in the image quality of the sensed image.

In order to prevent an increase in dark current due to a temperature rise, an image sensor using the above semiconductor is cooled by a thermoelectric conversion element. Such an example is described in Patent Document 2.
Japanese Patent Laid-Open No. 3-201579 (pages 1 and 2 and FIG. 1) Japanese Unexamined Patent Publication No. 2000-101888

  However, when power is supplied or taken out by a lead wire attached to the thermoelectric conversion element, there is a problem that connection with an external device such as a power source is troublesome or it cannot be directly attached depending on the attachment partner. there were.

  Furthermore, thermoelectric conversion elements can be reduced in size and thickness if the ratio of the cross-sectional area of the cross section parallel to the substrate of the thermoelectric elements constituting the element and the height of the elements is kept constant. In recent years, thermoelectric conversion elements have been made thinner and smaller. There are a method of attaching the lead wire to one substrate with solder or the like while it is housed between two substrates, and a method of attaching the lead wire to a substrate having a larger electrode attachment portion than the one substrate. However, as the thickness and size are reduced as described above, the former attachment method cannot ensure a sufficient gap between the substrates for the lead wires to enter. In the latter attachment method, the thickness of the lead wire and the rise of the solder used for joining may cause the height to be higher than the other substrate facing the substrate to which the lead wire is attached. In this case, there is a problem that the member to which the thermoelectric conversion element is attached and the lead wire are not in contact with each other, and the thermoelectric conversion element and the member cannot be attached well. FIG. 10 shows a schematic diagram of a conventional thermoelectric conversion element. Fig.10 (a) is a figure which shows a cross section among the outlines of the conventional thermoelectric conversion element, FIG.10 (b) is a figure which shows the figure seen from the upper surface.

  The present invention provides the following means in order to solve the above problems.

  The thermoelectric conversion element of the present invention joins a plurality of P-type thermoelectric elements made of P-type thermoelectric material, a plurality of N-type thermoelectric elements made of N-type thermoelectric material, and a pair of these P-type and N-type different thermoelectric elements. The first substrate and the first substrate having electrodes made of metal or the like that can form a PN junction pair, and the P-type and N-type thermoelectric elements are disposed between the first substrate and the first substrate so that the PN junction pair can be formed. A surface of the thermoelectric conversion element that is at least one of the first substrate and the second substrate on the side opposite to the surface that sandwiches the element. Has been drawn to. Thereby, the input of electric power to the thermoelectric conversion element or the extraction of electric power from the thermoelectric conversion element can be performed from the outer surface of the first substrate or the second substrate.

  In addition, the input / output electrodes of the thermoelectric conversion element of the present invention are routed to the outer surface of the substrate from the through holes provided in the first substrate or the second substrate or the end surfaces of the substrate. Thus, the input / output electrodes can be routed from the inner surface to the outer surface without using special wiring such as lead wires.

  In addition, in at least one of the first substrate and the second substrate of the thermoelectric conversion element of the present invention, the surface opposite to the surface sandwiching the element is metallized, and this metallized portion is routed from the surface sandwiching the element. Connected to the input / output electrodes. Thereby, this metallized part becomes an input / output electrode of the Peltier element.

  In addition, in at least one of the first substrate and the second substrate of the thermoelectric conversion element of the present invention, a plurality of electrically divided metallized portions are formed on the surface opposite to the surface sandwiching the element. An input / output electrode drawn from a surface sandwiching the element is electrically connected to one or more of the parts. Accordingly, simultaneously with the input / output electrodes, a metallized portion electrically separated from the input / output electrodes is formed on the outer surface of the substrate.

  Moreover, either the 1st board | substrate or the 2nd board | substrate of the thermoelectric conversion element of this invention uses the material which has a resin or resin as a main component as a base material. In this case, the resin preferably has heat resistance, and the thinner the resin, the better. In consideration of heat conduction and the like, the thickness of the resin layer is preferably about 0.1 to 100 μm.

  Moreover, either the 1st board | substrate or the 2nd board | substrate of the thermoelectric conversion element of this invention makes a base material the resin or the material which has resin as a main component, and copper is laminated | stacked. This copper layer receives heat from a base material made of a resin having low thermal conductivity, and diffuses this heat. In addition, by using this copper layer, it is possible to improve adhesion and bonding to a member attached to the thermoelectric conversion element. For example, connection by solder or the like is possible.

  According to the present invention, since the input / output electrodes of the thermoelectric conversion element are drawn out to the outer surface of the substrate constituting the thermoelectric conversion element, not only the power supply by the wiring from the inner surface side but also the electric power from the outer surface. Since the power can be supplied, the degree of freedom can be given to the wiring.

  In addition, by using through holes provided in the substrate of the thermoelectric conversion element or the end face of the substrate, the input / output electrodes are routed from the inner surface to the outer surface, so that unnecessary wiring can be routed and at the same time the substrate is manufactured. Since this routing wiring can be formed at the same time, the manufacturing cost can be reduced.

  By connecting the wiring routed from the inner surface of the substrate to the metallization portion provided on the outer surface, it becomes possible to supply power to the thermoelectric conversion element or output power from the thermoelectric conversion element from the outer surface. By connecting the metallized portion to a printed wiring board with wiring for connecting to the thermoelectric conversion element with a conductive bonding agent such as solder, power can be supplied or output from the printed wiring board or the like. Therefore, electrical connection between the thermoelectric conversion element and the outside is facilitated. Furthermore, the thermal connection to the thermoelectric conversion element can be improved by appropriately designing the structure of the outer metallized portion. In other words, electricity and heat can be connected simultaneously.

  In at least one of the first substrate and the second substrate of the thermoelectric conversion element, a plurality of electrically divided metallized portions are formed on the surface opposite to the surface sandwiching the element, and one of the metalized portions or By connecting the input / output electrodes routed from the surface that sandwiches the elements to each other, a metallized part that is electrically separated from the input / output electrodes is formed on the outer surface of the substrate simultaneously with the input / output electrodes. Is done. As a result, the metallized portion connected to the input / output electrodes is connected to a printed wiring board or the like that has been pre-wired, and the metalized portion that is not electrically connected to the metalized portion, such as a temperature control member or heat radiating member. It can be simultaneously connected to the member for directly using a bonding agent such as solder. As a result, heat dissipation and temperature controllability can be improved and power can be easily input and output to the thermoelectric conversion element, which greatly increases efficiency in manufacturing.

  A member constituting at least one of the first substrate and the second substrate constituting the thermoelectric conversion element is made of a resin or a resin-based material as a base material, so that the substrate is formed from the inner surface of the substrate by through holes or end surface wiring. Makes it easy to route the wiring to the outside. Resins, etc. are very close in thermal expansion coefficient to electrode materials and thermoelectric materials that make up thermoelectric conversion elements compared to inorganic materials such as ceramics. Works effectively against. The thickness is preferably about 0.1 μm to 100 μm in consideration of thermal conductivity.

  Either one of the first substrate and the second substrate constituting the thermoelectric conversion element is made of a resin or a resin-based material as a base material, and copper is laminated. This copper layer receives heat from a base material made of a resin having low thermal conductivity, and diffuses this heat. In addition, by using this copper layer, it is possible to improve adhesion and bonding to a member attached to the thermoelectric conversion element. For example, connection by solder or the like is possible.

(First embodiment)
Hereinafter, the thermoelectric conversion element according to the first embodiment of the present invention will be described with reference to the drawings. Fig.1 (a) is a schematic sectional drawing of the thermoelectric conversion element which is this invention. FIG. 1B is a schematic view of the thermoelectric conversion element as viewed from the direction of the second substrate 3. This thermoelectric conversion element has a structure in which a thermoelectric element 1 made of a thermoelectric material is sandwiched between a first substrate 2 made of alumina and a second substrate 3 made of alumina. Electrodes 4 for performing PN junction are formed on the surfaces of the first substrate 2 and the second substrate 3 on the thermoelectric element 1 side. Both ends of the electrode 4 for performing the PN junction on the first substrate 2 also serve as the input / output electrodes 5. A through hole hole 6 is formed in the first substrate 2. The inside of the through hole 6 is metallized and integrated with the metallized portion 7 on the outer surface, and is electrically connected.

  FIG. 2 is a view showing the structure of the outer surface of the first substrate. Two electrodes of the thermoelectric conversion element are drawn out through the through hole 6a and the through hole 6b and connected to the metallized part 7a and the metallized part 7b. The metallized part 7a and the metallized part 7b are respectively inserted into the thermoelectric conversion element. Output electrode. Among these, FIG. 2A shows an example in which each metallized portion has the same shape and has a structure extending to the bottom of the element 1 constituting the thermoelectric conversion element. FIG. 2B shows an example in which one metallized portion 7 a does not reach below the element 1 constituting the thermoelectric conversion element, and the metallized portion 7 b extends below the element 1. .

  Further, FIG. 3 shows an example in which a metallized part 8a or a metallized part 8b independent from the metallized part 7a and the metallized part 7b connected to the input / output electrodes is formed. In FIG. 3a, the metallized parts 7a and 7b connected to the input / output electrodes are formed only in the vicinity of the through hole 6a and the through hole 6b, and the independent metallized part 8a is separated from the metallized part 7a and the metallized part 7b by the first substrate. 2 is formed under the element 1 installation portion. FIG. 3B shows an example in which the independent metallized portion 8b extends between the metallized portion 7a and the metallized portion 7b formed only in the vicinity of the through hole 6a and the through hole 6b.

  The shape and the like of the outer surface metallized portion of the first substrate 1 may be considered other than those shown in FIGS. 2 and 3, but depending on the shape of the member to which the thermoelectric conversion element is attached, the metallized portions 7a and 7b and the independent metallized portion Needless to say, the shape and size of 8a and 8b, the material of the metallization layer, and the like are changed. In the first embodiment, the inner surface and the outer surface of the first substrate 2 are connected by the through hole 6. However, as shown in FIG. 4, the end surface metallized portion 9 is provided on the end surface of the first substrate 2. It is also possible to connect the inner and outer surfaces.

  FIG. 5 shows an example in which the thermoelectric conversion element manufactured in this embodiment is actually attached to an object. The thermoelectric conversion element 10 is connected to a member 12 on which a wiring 11 for performing input / output on the first substrate 2 side is connected by a solder 13. In this case, at least the material of the member 12 needs to be an insulator in the portion of the wiring 11, but the material, properties, and functions are not questioned as a whole. On the other hand, a member 14 is mounted on the second substrate 3. The connection between the second substrate 3 and the member 14 is made with thermally conductive grease or the like. If the outer surface of the second substrate 3 is metalized, the member 14 can be soldered if it can be soldered. You may do. When soldering is possible, the thermoelectric conversion element 10 can be attached with high efficiency because electrical and thermal connection can be achieved by a single soldering. The attached thermoelectric conversion element 10 may be used as a cooling element or a power generation conversion element.

  The thermoelectric conversion element 10 can be used for power generation and cooling, but in either case, either the member 12 or the member 14 may be on the high temperature side or the low temperature side.

(Second Embodiment)
Next, a second embodiment according to the present invention will be described.

  In the present embodiment, polyimide resin is used for the first substrate 2a, and alumina is used for the second substrate 3a. FIG. 6 is a schematic cross-sectional view of the thermoelectric conversion element according to the second embodiment. A polyimide resin is inferior in terms of high thermal conductivity compared to a ceramic material such as alumina, but is excellent in terms of workability, flexibility, strength, and the like. The thermal resistance is lowered by reducing the thickness of the polyimide resin as much as possible. The thickness is preferably about 0.1 μm to 100 μm. When the thickness of the polyimide resin layer is thin, the polyimide resin layer is formed by applying and curing a liquid polyimide resin on the copper foil that becomes the metallized portion. If it is thick, a film-like polyimide resin may be metallized with a metal such as copper. After producing a member in which a metal such as polyimide resin and copper is laminated, the first substrate 2a can be easily produced by forming a PN electrode, a metallized portion, etc. by using a technique such as drilling, plating, photolithography, etc. be able to. One second substrate 3a is easily produced by plating on alumina and photolithography. When a bismuth / tellurium-based material is used as the thermoelectric material sandwiched between the first substrate 2a and the second substrate 3a, the element end face of bismuth / tellurium is nickel-plated to perform PN bonding. A thermoelectric conversion element is produced by soldering to the substrate.

  When using the thermoelectric conversion element produced in this way as a cooling element, it is preferable to use the 1st board | substrate 2a in which the input electrode is formed as a cooling side. When a thermoelectric conversion element is used as the cooling element, the amount of heat passing through the cooling side substrate is considerably smaller than the amount of heat passing through the heat dissipation side substrate. When an organic material such as polyimide resin that is inferior in heat conduction is used as a substrate, the temperature difference generated by reducing the amount of heat passing through as much as possible can be reduced, so in the case of this embodiment, the first substrate 2a is set on the cooling side. Higher performance can be achieved.

  Moreover, the combination with respect to the material difference of the base material which comprises a 1st board | substrate and a 2nd board | substrate can be performed arbitrarily. FIG. 7 (a) uses a resin base material for both the first substrate and the second substrate, forms a metallized portion 15 on the outer surface of the second substrate 3b, and connects the second substrate 3b to an external member by soldering. It is possible. FIG. 7B is a view showing an example in which an alumina substrate is used as the first substrate and a resin base material in which the metallized portion 15 is formed on the outer surface is used as the second substrate.

As for the arrangement of the metallized portion 15 on the outer surface of the first substrate, the one shown in FIGS. 2 and 3 can be used as in the first embodiment.
(Third embodiment)
A third embodiment according to the present invention will be described.

FIG. 8 is a schematic view of a longitudinal section of a thermoelectric conversion element according to the third embodiment.
Through holes 6d and 6e are formed in both the first substrate 2d and the second substrate 3d, and the input / output electrodes 5a and 5b of the thermoelectric conversion elements are formed in separate substrates, the first substrate 2d and the second substrate 3d. . FIGS. 9A to 9C are views showing the arrangement of the metallized portions on the outer surface of the first substrate 2d. The second substrate 3d is substantially the same as FIGS. 9A to 9C except that the position of the through hole 6e is different.

  According to this structure, one of the input / output electrodes of the thermoelectric conversion element is on the high temperature side and the other is on the low temperature side. If connection wiring is provided in advance on the member to which the thermoelectric conversion element is attached, solder or the like can be easily connected. Unlike the case where both electrodes are provided on one substrate, an electrical short due to the flow of solder or the like can be prevented when connecting to a member.

It is the figure which showed the outline of the thermoelectric conversion element concerning 1st Embodiment of this invention. It is the figure which showed the metallization part connected to the input / output electrode of the outer surface of the 1st board | substrate of 1st Embodiment of this invention. It is the figure which showed the metallization part independent of the metallization part connected to the input / output electrode of the outer surface of the 1st board | substrate of 1st Embodiment of this invention. It is the figure which showed the schematic cross section of the thermoelectric conversion element which connected the inner surface and the outer surface by providing an end surface metallization part in the end surface of the 1st board | substrate of 1st Embodiment of this invention. It is the figure which showed the example which attached the thermoelectric conversion element of this invention produced in 1st Embodiment of this invention to the target object. It is the figure which showed the schematic cross section of the thermoelectric conversion element concerning 2nd Embodiment of this invention. It is a figure which shows the schematic cross section of the thermoelectric conversion element at the time of changing the combination of the 1st board | substrate and 2nd board | substrate which comprise the thermoelectric conversion element in 2nd Embodiment of this invention. It is the figure which showed the schematic cross section of the thermoelectric conversion element concerning 3rd Embodiment of this invention. It is the figure which showed arrangement | positioning of the outer surface metallization part of the 1st board | substrate which comprises the thermoelectric conversion element of 3rd Embodiment of this invention. It is the figure which showed the outline of the conventional thermoelectric conversion element for contrast with this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Thermoelectric element 2, 2a, 2b, 2c, 2d ... 1st board | substrate 3, 3a, 3b, 3c, 3d ... 2nd board | substrate 4 ... Electrode 5 for performing PN junction ... Input / output electrodes 6, 6 a, 6 b, 6 c, 6 d, 6 e... Through holes 7, 7 a, 7 b, 7 c, 7 d... External metallized portions 8 a, 8 b, 8 c, 8 d.・ ・ ・ End metallization part 10 ・ ・ ・ thermoelectric conversion element 11 ・ ・ ・ wiring 12 for input / output ・ ・ ・ member 13 attached to thermoelectric conversion element ・ ・ ・ solder 14 ・ ・ ・ attached to thermoelectric conversion element Member 15 ... Metallized portion 16 ... Lead wire

Claims (7)

A plurality of P-type thermoelectric elements made of P-type thermoelectric material, a plurality of N-type thermoelectric elements made of N-type thermoelectric material, and a pair of these P-type and N-type different thermoelectric elements can be joined to form a PN junction pair And a second substrate having an electrode that can be formed with a PN junction pair disposed between the P-type and N-type thermoelectric elements together with the first substrate. In the conversion element,
One of the input / output electrodes of the thermoelectric conversion element is provided on one of the first substrate and the second substrate , the other of the input / output electrodes is provided on the other of the first substrate and the second substrate, and A thermoelectric conversion device, wherein the thermoelectric conversion device is drawn to a surface opposite to a surface sandwiching the element. 2. The first substrate and the second substrate of the thermoelectric conversion element, wherein the electrode is routed from the surface sandwiching the element to the opposite surface by a through hole provided in the substrate. Thermoelectric conversion device. 2. The thermoelectric conversion device according to claim 1 , wherein in the first substrate and the second substrate of the thermoelectric conversion element, the electrode is routed from the surface sandwiching the element to the opposite surface from the end surface of the substrate. 3. . In the first substrate and the second substrate of the thermoelectric conversion element, the surface opposite to the surface sandwiching the element is metallized, and the metallized portion is connected to the input / output electrode routed from the surface sandwiching the element. The thermoelectric conversion device according to any one of claims 1 to 3, wherein the thermoelectric conversion device is characterized in that: In the first substrate and the second substrate of the thermoelectric conversion element, a plurality of electrically divided metallized portions are formed on a surface opposite to a surface sandwiching the elements , and an element is disposed on one or a plurality of the metalized portions. The thermoelectric converter according to any one of claims 1 to 4, wherein the input / output electrodes routed from the sandwiching surface are electrically connected. The thermoelectric device according to any one of claims 1 to 5, wherein the first substrate and the second substrate of the thermoelectric conversion element are made of a resin or a resin-based material as a base material. Conversion device. 7. The first substrate and the second substrate of the thermoelectric conversion element, wherein a base material is a resin or a resin-based material, and copper is laminated on the base material. The thermoelectric conversion apparatus of any one of these.

Images