JP2021018113A - Circuit board and temperature measuring device - Google Patents

Abstract

To provide a circuit board and a temperature measuring device which include fewer components, are small in space with low cost, and capable of reducing a temperature difference between a pair of terminals.SOLUTION: A circuit board 1 comprises: a first wiring pattern 11 connected to a first terminal 10; a second wiring pattern 21 connected to a second terminal 20; and a first wiring layer and a second wiring layer. The first wiring pattern 11 includes, on one of the first wiring layer and the second wiring layer, a first heat transfer part 12a extending from the first terminal 10 toward the second terminal 20. The second wiring pattern 21 includes, on the other of the first wiring layer and the second wiring layer, a first heat transfer part 22a extending from the second terminal 20 toward the first terminal 10. The first heat transfer part 12a of the first wiring pattern 11 and the first heat transfer part 22a of the second wiring pattern 21 face each other. The temperature measuring device includes the circuit board 1, and measures temperature via a thermocouple by connecting the thermocouple to the first terminal 10 and the second terminal 20.SELECTED DRAWING: Figure 5

Description

The present disclosure relates to circuit boards and temperature measuring instruments.

A temperature measuring device having a pair of terminals to which a thermocouple is connected and measuring a temperature by the thermocouple is known. Such a temperature measuring instrument has a structure that reduces the temperature difference between the pair of terminals in order to improve the accuracy of measuring the temperature by the thermocouple. For example, the structure described in Patent Document 1 has a heat reflector arranged between a pair of terminals connected to a circuit board and a heat generating source, and a metal core provided inside the circuit board. There is. According to this structure, the heat conduction from the heat source to the circuit board is suppressed by the heat reflector, and the heat conducted to the circuit board is diffused by the metal core, so that the temperature difference between the pair of terminals is reduced. be able to.

Jikkenhei 6-2183 Gazette

However, a structure as described in Patent Document 1 requires the number of parts, space, and cost for providing the heat reflector and the metal core.

An object of the present disclosure is to provide a circuit board and a temperature measuring device capable of reducing the temperature difference between a pair of terminals with a small number of parts, a small space, and a low cost.

The circuit board according to some embodiments has a first wiring pattern connected to the first terminal and a second wiring pattern connected to the second terminal, and includes a first wiring layer and a second wiring layer. In the circuit board, the first wiring pattern has a heat transfer portion extending from the first terminal to the second terminal on one of the first wiring layer and the second wiring layer, and the second wiring pattern is , The other side of the first wiring layer and the second wiring layer has a heat transfer portion extending from the second terminal to the first terminal, and the heat transfer portion of the first wiring pattern and the heat transfer portion of the second wiring pattern The parts face each other. According to such a configuration, the heat transfer portion of the first wiring pattern and the heat transfer portion of the second wiring pattern can transfer heat to each other, so that the temperature difference between the first terminal and the second terminal Can be made smaller. Further, since the heat transfer portion is formed by the wiring pattern, it is possible to obtain a circuit board having a small number of parts, a small space, and a low cost.

In one embodiment, in the above configuration, the circuit board is another heat transfer unit in which the first wiring pattern extends from the first terminal to the second terminal on the other side of the first wiring layer and the second wiring layer. The second wiring pattern has another heat transfer portion extending from the second terminal to the first terminal on one of the first wiring layer and the second wiring layer, and the first wiring pattern has. The other heat transfer unit and the other heat transfer unit of the second wiring pattern may face each other. According to such a configuration, the other heat transfer portions of the first wiring pattern and the other heat transfer portions of the second wiring pattern can transfer heat to each other. Further, in one of the first wiring layer and the second wiring layer, the heat transfer portion of the first wiring pattern and the other heat transfer portion of the second wiring pattern can transfer heat to each other. Further, on the other side of the first wiring layer and the second wiring layer, another heat transfer portion of the first wiring pattern and the heat transfer portion of the second wiring pattern can transfer heat to each other. Therefore, the temperature difference between the first terminal and the second terminal can be made smaller.

In one embodiment, the circuit board may have a heat source having a different distance to the first terminal and a different distance to the second terminal in the above configuration. According to such a configuration, it is possible to realize a circuit board having a small number of parts, a small space, and a low cost, which can reduce the temperature difference between a pair of terminals caused by heat conduction from a heat source of the circuit board itself. be able to.

In one embodiment, the circuit board may have a slit located between the terminal and the heat source closer to the heat source in the above configuration. According to such a configuration, the low thermal conductivity of the space in the slit can suppress the transfer of heat from the heat source to the terminals closer to the heat source, so that the temperature between the pair of terminals can be suppressed. The difference can be made smaller.

In one embodiment, the circuit board may have a pattern located between the terminal and the heat source farther from the heat source in the above configuration. According to such a configuration, heat transfer through the pattern can promote heat transfer from the heat source to the terminal farther from the heat source, so that the temperature difference between the pair of terminals can be increased. It can be made smaller.

In one embodiment, in the above configuration, the heat transfer portion of the wiring pattern connected to the terminal farther from the heat source extends toward the heat source beyond the terminal closer to the heat source. It may have an extension to be used. According to such a configuration, the heat transfer through the extension portion can promote the heat transfer from the heat generation source to the terminal farther from the heat generation source, so that the temperature difference between the pair of terminals can be promoted. Can be made smaller.

In one embodiment, in the above configuration, the circuit board has another heat transfer portion of a wiring pattern connected to a terminal farther from the heat source toward the heat source beyond the terminal closer to the heat source. It may have other extensions that extend. According to such a configuration, heat transfer from the heat generation source to the terminal farther from the heat generation source can be promoted by heat transfer through the other extension portion, and thus heat transfer between the pair of terminals can be promoted. The temperature difference can be made smaller.

In one embodiment, in the above configuration, the heat transfer portion of the first wiring pattern and the heat transfer portion of the second wiring pattern may each form a band shape in the circuit board. According to such a configuration, the heat transfer portion of the first wiring pattern and the heat transfer portion of the second wiring pattern can transfer heat to each other satisfactorily.

In one embodiment, in the above configuration, the circuit board may have a band shape in each of the other heat transfer portions of the first wiring pattern and the other heat transfer portions of the second wiring pattern. According to such a configuration, the other heat transfer portions of the first wiring pattern and the other heat transfer portions of the second wiring pattern can transfer heat to each other satisfactorily.

In one embodiment, the circuit board may have a pattern extending from the side of the terminal farther from the heat source to the side of the heat source beyond the slit in the above configuration. With such a configuration, it is possible to enable efficient transfer of heat through the pattern.

In one embodiment, the circuit board may have a portion of the pattern extending along the slit between the heat source and the slit in the above configuration. With such a configuration, it is possible to enable efficient transfer of heat through the pattern.

In one embodiment, in the above configuration, the circuit board may have a first wiring pattern and a second wiring pattern each made of copper. According to such a configuration, the high thermal conductivity of copper makes it possible to efficiently reduce the temperature difference between the pair of terminals.

In one embodiment, the circuit board may have a pattern made of copper in the above configuration. According to such a configuration, the high thermal conductivity of copper makes it possible to efficiently reduce the temperature difference between the pair of terminals.

The temperature measuring device according to some embodiments has a circuit board having the above configuration, and measures the temperature via the thermocouple by connecting a thermocouple to the first terminal and the second terminal. According to such a configuration, the temperature difference between the pair of terminals can be reduced with a small number of parts, a small space, and a low cost.

According to the present disclosure, it is possible to provide a circuit board and a temperature measuring device capable of reducing the temperature difference between a pair of terminals with a small number of parts, a small space, and a low cost.

It is a perspective view which shows the circuit board which concerns on a comparative example. It is explanatory drawing which shows the temperature distribution of the circuit board shown in FIG. It is explanatory drawing which shows the temperature distribution when the distance between a pair of terminals and a heat source is increased in the circuit board shown in FIG. It is explanatory drawing which shows the temperature distribution when the heat transfer material is provided to a pair of terminals in the circuit board shown in FIG. It is a perspective view which shows the state which a pair of terminals are connected to the circuit board which concerns on one Embodiment. (A) is a top view showing a second wiring layer of the circuit board shown in FIG. 5, and (b) is a sectional view taken along the line AA of (a). It is a top view which shows through the 1st wiring layer of the circuit board shown in FIG. It is sectional drawing which shows the modification of the circuit board shown in FIG. It is a top view which shows the 2nd wiring layer in another modification of the circuit board shown in FIG.

Hereinafter, embodiments according to the present disclosure will be illustrated in detail with reference to the drawings.

First, with reference to FIGS. 1 to 4, a method of reducing the temperature difference between the pair of terminals 10 and 20 including the first terminal 10 and the second terminal 20 in the circuit board 1 according to the comparative example will be described.

As shown in FIG. 1, the circuit board 1 according to this comparative example has a first wiring pattern 11 connected to the first terminal 10, a second wiring pattern 21 connected to the second terminal 20, and a first terminal. It has a heat generating source 2 in which the distance to 10 and the distance to the second terminal 20 are different. The first wiring pattern 11 and the second wiring pattern 21 are provided between the first wiring layer and the second wiring layer via through holes, respectively. In the circuit board 1, the first wiring layer is provided on the first main surface (lower surface in FIG. 1), and the second wiring layer is provided on the second main surface (upper surface in FIG. 1) located on the opposite side of the first main surface. It is configured as a double-sided substrate provided. The pair of terminals 10 and 20 each project from the second main surface. For convenience of explanation, the first main surface will be the lower surface and the second main surface will be the upper surface.

The first wiring pattern 11 and the second wiring pattern 21 are each connected to a circuit (not shown) provided on the circuit board 1. The circuit board 1 constitutes a temperature measuring device that measures a temperature via a thermocouple by connecting a thermocouple to the first terminal 10 and the second terminal 20.

As shown in FIG. 2, the circuit board 1 according to this comparative example has a temperature distribution in which the absolute value of the temperature gradient gradually decreases as the distance from the heat source 2 increases. Therefore, as one method for reducing the temperature difference between the pair of terminals 10 and 20, as shown in FIG. 3, the distance between the pair of terminals 10 and 20 and the heat source 2 can be increased. However, such a method requires a space for increasing the above distance, and cannot be adopted when the space constraint is large. Further, as another method for reducing the temperature difference between the pair of terminals 10 and 20, as shown in FIG. 4, the pair of terminals 10 and 20 have high thermal conductivity such as a heat radiating sheet or a metal core. It is mentioned that the heat transfer material 3 having the above is provided. However, such a method requires the number of parts, space, and cost for providing the heat transfer material 3.

Next, the circuit board 1 according to one embodiment will be illustrated with reference to FIGS. 5 to 7, a modified example will be exemplified with reference to FIG. 8, and another modified example will be illustrated with reference to FIG. explain. These circuit boards 1 have realized a small number of parts, a small space, and a low cost as compared with the circuit board 1 according to the above-mentioned comparative example. In FIGS. 5 to 9, the elements corresponding to the elements shown in FIGS. 1 to 4 are designated by the same reference numerals.

As shown in FIGS. 5 to 7, the circuit board 1 according to the present embodiment includes a first wiring pattern 11 connected to the first terminal 10 and a second wiring pattern 21 connected to the second terminal 20. It has a heat generating source 2 in which the distance to the first terminal 10 and the distance to the second terminal 20 are different. The first wiring pattern 11 and the second wiring pattern 21 are provided between the first wiring layer and the second wiring layer via through holes, respectively. In the circuit board 1, the first wiring layer is provided on the first main surface (lower surface in FIG. 5), and the second wiring layer is provided on the second main surface (upper surface in FIG. 5) located on the opposite side of the first main surface. It is configured as a double-sided substrate provided. The pair of terminals 10 and 20 each project from the second main surface. For convenience of explanation, the first main surface will be the lower surface and the second main surface will be the upper surface.

The first wiring pattern 11 and the second wiring pattern 21 are each connected to a circuit (not shown) provided on the circuit board 1. The circuit board 1 constitutes a temperature measuring device that measures a temperature via a thermocouple by connecting a thermocouple to the first terminal 10 and the second terminal 20.

The first wiring pattern 11 is a first heat transfer portion as a heat transfer portion extending from the first terminal 10 to the second terminal 20 in the first wiring layer as one of the first wiring layer and the second wiring layer. It has a part 12a. The second wiring pattern 21 is a first heat transfer portion as a heat transfer portion extending from the second terminal 20 to the first terminal 10 in the second wiring layer as the other side of the first wiring layer and the second wiring layer. It has a portion 22a. The first heat transfer portion 12a of the first wiring pattern 11 and the first heat transfer portion 22a of the second wiring pattern 21 face each other. The first heat transfer portion 12a of the first wiring pattern 11 and the first heat transfer portion 22a of the second wiring pattern 21 each have a band shape.

The first wiring pattern 11 is a second as another heat transfer unit extending from the first terminal 10 to the second terminal 20 in the second wiring layer as the other side of the first wiring layer and the second wiring layer. It has a heat transfer unit 12b. The second wiring pattern 21 is a second heat transfer unit extending from the second terminal 20 to the first terminal 10 in the first wiring layer as one of the first wiring layer and the second wiring layer. It has a heat transfer unit 22b. The second heat transfer portion 12b of the first wiring pattern 11 and the second heat transfer portion 22b of the second wiring pattern 21 face each other. The second heat transfer portion 12b of the first wiring pattern 11 and the second heat transfer portion 22b of the second wiring pattern 21 each have a band shape.

The first heat transfer unit 12a as the heat transfer unit of the first wiring pattern 11 as a wiring pattern connected to the terminal farther from the heat generation source 2 is the second terminal 20 as a terminal closer to the heat generation source 2. It has a first extension portion 13a as an extension portion extending beyond the heat source 2 toward the heat generation source 2.

The circuit board 1 has a slit 4 located between the second terminal 20 and the heat source 2 as terminals closer to the heat source 2. The slit 4 is provided between the first wiring layer and the second wiring layer. The slit 4 extends in a direction orthogonal to the axis passing through the first terminal 10 and the second terminal 20 in a top view, and the extending direction extends to the first terminal 10, the second terminal 20, and heat generation. It can be changed as appropriate according to the arrangement of the source 2.

The heat generation source 2 is provided on the axis passing through the first terminal 10 and the second terminal 20 in a top view, but the arrangement of the first terminal 10, the second terminal 20, and the heat generation source 2 can be changed as appropriate. .. The heat generation source 2 is composed of a circuit such as a power supply circuit or a measurement circuit.

The circuit board 1 has a pattern 31 located between the first terminal 10 and the heat source 2 as terminals farther from the heat source 2. The pattern 31 extends from the side of the first terminal 10 as a terminal farther from the heat source 2 to the side of the heat source 2 beyond the slit 4. The pattern 31 has an extending portion 32 as a portion extending along the slit 4 between the heat generating source 2 and the slit 4. The pattern 31 is provided in the first wiring layer, but is not limited to this, and may be provided in the second wiring layer instead of the first wiring layer, or both the first wiring layer and the second wiring layer. It may be provided in.

The first wiring pattern 11, the second wiring pattern 21, and the pattern 31 are each made of copper, but the present invention is not limited to this, and various materials can be used. The insulating layer located between the first wiring layer and the second wiring layer is made of glass epoxy resin (FR-4), but is not limited to this, and can be made of various materials. The thermal conductivity of the air filling the space in the slit 4, the glass epoxy resin constituting the insulating layer, and the copper constituting the first wiring pattern 11, the second wiring pattern 21 and the pattern 31 is, for example, the same. 0.0241, 0.45, 403 [W / (m · K)] in the order of description.

Although the circuit board 1 according to the present embodiment is configured as a double-sided substrate, it may be configured as a laminated substrate as in the modified example shown in FIG.

In this modification, the first wiring pattern 11 has a third heat transfer portion 12c extending from the first terminal 10 to the second terminal 20 in the third wiring layer, and the second wiring pattern 21 is the second. The four wiring layers have a third heat transfer portion 22c extending from the second terminal 20 to the first terminal 10, and the third heat transfer portion 12c of the first wiring pattern 11 and the third of the second wiring pattern 21. They face each other with the heat transfer unit 22c. Further, in this modification, the first wiring pattern 11 has a fourth heat transfer portion 12d extending from the first terminal 10 to the second terminal 20 in the fourth wiring layer, and the second wiring pattern 21 The third wiring layer has a fourth heat transfer portion 22d extending from the second terminal 20 to the first terminal 10, and the fourth heat transfer portion 12d and the second wiring pattern 21 of the first wiring pattern 11 have. They face each other with the fourth heat transfer unit 22d.

Further, the third heat transfer portion 12c of the first wiring pattern 11 and the first heat transfer portion 22a of the second wiring pattern 21 face each other. Further, the fourth heat transfer portion 22d of the second wiring pattern 21 and the second heat transfer portion 12b of the first wiring pattern 11 face each other.

By forming many portions where the heat transfer portions face each other by utilizing the laminated structure in this way, the temperature difference between the first terminal 10 and the second terminal 20 can be efficiently reduced.

Further, in the above-described embodiment, the first heat transfer portion 12a as the heat transfer portion of the first wiring pattern 11 as the wiring pattern connected to the terminal farther from the heat generation source 2 has the first extension portion 13a. However, instead of or in addition to this, as in the modified example shown in FIG. 9, another heat transfer unit of the first wiring pattern 11 as a wiring pattern connected to a terminal farther from the heat generation source 2. The second heat transfer portion 12b may have a second extension portion 13b as another extension portion.

It goes without saying that the above-described embodiment is merely an example of the present disclosure and can be variously modified.

For example, the second heat transfer portion 12b of the first wiring pattern 11 and the second heat transfer portion 22b of the second wiring pattern 21 may not be provided. The first heat transfer portion 12a of the first wiring pattern 11 may not have the first extension portion 13a. The circuit board 1 may not be provided with the slit 4. A heat source 2 having a different distance to the first terminal 10 and a different distance to the second terminal 20 may be arranged separately from the circuit board 1. The pattern 31 may not be provided with the extending portion 32. The pattern 31 may not extend from the side of the first terminal 10 to the side of the heat generating source 2 beyond the slit 4. The circuit board 1 may not be provided with the pattern 31. The circuit board 1 can be applied to devices other than temperature measuring instruments, for example, temperature calibrators, and various measuring instruments, calibrators, and the like.

1 Circuit board 2 Heat transfer source 3 Heat transfer material 4 Slit 10 1st terminal 11 1st wiring pattern 12a 1st heat transfer part 12b 2nd heat transfer part 12c 3rd heat transfer part 12d 4th heat transfer part 13a 1st extension part 13b 2nd extension part 20 2nd terminal 21 2nd wiring pattern 22a 1st heat transfer part 22b 2nd heat transfer part 22c 3rd heat transfer part 22d 4th heat transfer part 31 pattern 32 extending part

Claims (7)

A circuit board having a first wiring pattern connected to a first terminal and a second wiring pattern connected to a second terminal, and including a first wiring layer and a second wiring layer.
The first wiring pattern has a heat transfer portion extending from the first terminal to the second terminal on one of the first wiring layer and the second wiring layer.
The second wiring pattern has a heat transfer portion extending from the second terminal toward the first terminal on the other side of the first wiring layer and the second wiring layer.
A circuit board in which the heat transfer portion of the first wiring pattern and the heat transfer portion of the second wiring pattern face each other. The first wiring pattern has another heat transfer portion extending from the first terminal to the second terminal on the other side of the first wiring layer and the second wiring layer.
The second wiring pattern has another heat transfer portion extending from the second terminal toward the first terminal in the one of the first wiring layer and the second wiring layer.
The circuit board according to claim 1, wherein the other heat transfer portion of the first wiring pattern and the other heat transfer portion of the second wiring pattern face each other. The circuit board according to claim 1 or 2, which has a heat generating source in which the distance to the first terminal and the distance to the second terminal are different. The circuit board according to claim 3, further comprising a slit located between the terminal and the heat source, which is closer to the heat source. The circuit board according to claim 3 or 4, which has a pattern located between the terminal and the heat source, which is farther from the heat source. The heat transfer portion of the wiring pattern connected to the terminal farther from the heat source has an extension extending toward the heat source beyond the terminal closer to the heat source. The circuit board according to any one of claims 3 to 5. The circuit board according to any one of claims 1 to 6 is provided.
A temperature measuring device that measures a temperature via a thermocouple by connecting a thermocouple to the first terminal and the second terminal.

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