JP7252851B2 - Circuit board and temperature measuring instrument - Google Patents

Description

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

A temperature measuring instrument is known that has a pair of terminals to which a thermocouple is connected and measures temperature by the thermocouple. Such a temperature measuring instrument employs a structure that reduces the temperature difference between a pair of terminals in order to improve the accuracy of temperature measurement by a thermocouple. For example, the structure described in Patent Document 1 has a heat reflector disposed between a pair of terminals connected to a circuit board and a heat source, and a metal core provided inside the circuit board. there is According to this structure, the conduction of heat 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, thereby reducing the temperature difference between the pair of terminals. be able to.

Japanese Utility Model Laid-Open No. 6-2183

However, the 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 that can reduce the temperature difference between a pair of terminals with a small number of parts, a small space, and a low cost.

A circuit board according to some embodiments has a first wiring pattern connected to a first terminal and a second wiring pattern connected to a second terminal, and includes a first wiring layer and a second wiring layer. A circuit board, wherein the first wiring pattern has a heat transfer portion extending from the first terminal toward the second terminal on one of the first wiring layer and the second wiring layer, and the second wiring pattern and a heat transfer portion extending from the second terminal toward the first terminal on the other of the first wiring layer and the second wiring layer, and the heat transfer portion of the first wiring pattern and the heat transfer of the second wiring pattern. are facing each other. With 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 is reduced. can be made smaller. Moreover, since the heat transfer portion is configured by the wiring pattern, the circuit board can be made with a small number of parts, a small space, and a low cost.

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

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

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

In one embodiment, the circuit board may have a pattern located between the terminal farther from the heat source and the heat source in the above configuration. According to such a configuration, heat transfer via the pattern facilitates heat transfer from the heat source to the terminal farther away from the heat source, thereby reducing the temperature difference between the pair of terminals. can be made smaller.

In one embodiment, the circuit board has the above configuration, wherein 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 that According to such a configuration, heat transfer via the extension portion can promote heat transfer from the heat source to the terminal farther away from the heat source, thereby reducing the temperature difference between the pair of terminals. can be made smaller.

In one embodiment, in the circuit board having the above configuration, the other 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 other extensions that extend. According to such a configuration, heat transfer via the other extension can promote heat transfer from the heat source to the terminal farther from the heat source. The temperature difference can be made smaller.

In one embodiment, in the circuit board having the above configuration, the heat transfer portion of the first wiring pattern and the heat transfer portion of the second wiring pattern may each be strip-shaped. 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 well to each other.

In one embodiment, in the above configuration of the circuit board, the other heat transfer portion of the first wiring pattern and the other heat transfer portion of the second wiring pattern may each be strip-shaped. According to such a configuration, the other heat transfer portion of the first wiring pattern and the other heat transfer portion of the second wiring pattern can transfer heat well to each other.

In one embodiment, in the circuit board having the above configuration, the pattern may extend from the side of the terminal farther from the heat source to the side of the heat source beyond the slit. Such a configuration enables efficient transfer of heat through the pattern.

In one embodiment, in the above configuration, the circuit board may have a portion where the pattern extends along the slit between the heat source and the slit. Such a configuration enables efficient transfer of heat through the pattern.

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

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

A temperature measuring instrument according to some embodiments has the circuit board configured as described above, and measures temperature via the thermocouple by connecting the 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 that can reduce the temperature difference between a pair of terminals with a small number of parts, a small space, and a low cost.

FIG. 5 is a perspective view showing a circuit board according to a comparative example; FIG. 2 is an explanatory diagram showing the temperature distribution of the circuit board shown in FIG. 1; 2 is an explanatory diagram showing a temperature distribution when the distance between a pair of terminals and a heat source is increased in the circuit board shown in FIG. 1; FIG. FIG. 2 is an explanatory diagram showing a temperature distribution when a heat transfer material is provided on a pair of terminals in the circuit board shown in FIG. 1; FIG. 4 is a perspective view showing a state in which a pair of terminals are connected to a circuit board according to one embodiment; 6A is a top view showing a second wiring layer of the circuit board shown in FIG. 5, and FIG. 6B is a cross-sectional view taken along line AA of FIG. FIG. 6 is a top view showing through the first wiring layer of the circuit board shown in FIG. 5 ; 6 is a cross-sectional view showing a modification of the circuit board shown in FIG. 5; FIG. 6 is a top view showing a second wiring layer in another modification of the circuit board shown in FIG. 5; FIG.

Embodiments according to the present disclosure will be exemplified in detail below with reference to the drawings.

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

As shown in FIG. 1, the circuit board 1 according to this comparative example includes a first wiring pattern 11 connected to the first terminal 10, a second wiring pattern 21 connected to the second terminal 20, and the first terminal 10 and a heat source 2 whose distance to the second terminal 20 is different. The first wiring pattern 11 and the second wiring pattern 21 are respectively provided between the first wiring layer and the second wiring layer via through holes. The circuit board 1 has a first wiring layer on a first main surface (lower surface in FIG. 1) and a second wiring layer on a second main surface (upper surface in FIG. 1) opposite to the first main surface. It is configured as a double-sided board provided with A pair of terminals 10 and 20 each protrude from the second main surface. For convenience of explanation, the description will be made with the first principal surface as the bottom surface and the second principal surface as the top surface.

Each of the first wiring pattern 11 and the second wiring pattern 21 is connected to a circuit (not shown) provided on the circuit board 1 . By connecting thermocouples to the first terminal 10 and the second terminal 20, the circuit board 1 constitutes a temperature measuring device that measures temperature via the thermocouples.

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, one method for reducing the temperature difference between the pair of terminals 10 and 20 is to increase the distance between the pair of terminals 10 and 20 and the heat source 2 as shown in FIG. However, such a method requires a space for increasing the distance, and cannot be adopted when the space is severely restricted. As another method for reducing the temperature difference between the pair of terminals 10 and 20, as shown in FIG. 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 modification will be illustrated with reference to FIG. 8, and another modification will be illustrated with reference to FIG. explain. These circuit boards 1 realize a reduction in the number of components, a small space, and a low cost as compared with the circuit board 1 according to the comparative example described above. 5 to 9, elements corresponding to those shown in FIGS. 1 to 4 are denoted by the same reference numerals.

As shown in FIGS. 5 to 7, the circuit board 1 according to this embodiment includes a first wiring pattern 11 connected to the first terminal 10, a second wiring pattern 21 connected to the second terminal 20, The heat source 2 has a different distance to the first terminal 10 and a distance to the second terminal 20 . The first wiring pattern 11 and the second wiring pattern 21 are respectively provided between the first wiring layer and the second wiring layer via through holes. The circuit board 1 has a first wiring layer on the first main surface (lower surface in FIG. 5) and a second wiring layer 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 board provided with A pair of terminals 10 and 20 each protrude from the second main surface. For convenience of explanation, the description will be made with the first principal surface as the bottom surface and the second principal surface as the top surface.

Each of the first wiring pattern 11 and the second wiring pattern 21 is connected to a circuit (not shown) provided on the circuit board 1 . By connecting thermocouples to the first terminal 10 and the second terminal 20, the circuit board 1 constitutes a temperature measuring device that measures temperature via the thermocouples.

The first wiring pattern 11 is a first heat transfer portion extending from the first terminal 10 toward the second terminal 20 in the first wiring layer as one of the first wiring layer and the second wiring layer. It has a portion 12a. The second wiring pattern 21 is a first heat transfer portion extending from the second terminal 20 toward the first terminal 10 in the second wiring layer as the other 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 are band-shaped.

The first wiring pattern 11 extends from the first terminal 10 toward the second terminal 20 in the second wiring layer as the other of the first wiring layer and the second wiring layer, and serves as another heat transfer portion. It has a heat transfer portion 12b. The second wiring pattern 21 extends from the second terminal 20 toward the first terminal 10 in the first wiring layer as one of the first wiring layer and the second wiring layer, and serves as another heat transfer portion. It has a heat transfer portion 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 are band-shaped.

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

The circuit board 1 has a slit 4 positioned between the heat source 2 and a second terminal 20 as a terminal 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 an axis passing through the first terminal 10 and the second terminal 20 in top view, and the extending direction is the first terminal 10, the second terminal 20, and the heat generation. Appropriate changes are possible according to the arrangement of the source 2 .

The heat source 2 is provided on an 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 source 2 can be changed as appropriate. . The heat source 2 is composed of a circuit such as a power supply circuit or a measurement circuit, for example.

The circuit board 1 has a pattern 31 positioned between the heat source 2 and the first terminal 10 as a terminal 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 across the slit 4 to the side of the heat source 2 . The pattern 31 has an extension portion 32 as a portion extending along the slit 4 between the heat source 2 and the slit 4 . Although the pattern 31 is provided in the first wiring layer, it is not limited to this, and may be provided in the second wiring layer instead of the first wiring layer, or may be provided in both the first wiring layer and the second wiring layer. may be provided in

The first wiring pattern 11, the second wiring pattern 21, and the pattern 31 are each made of copper, but are not limited to this and can be made of various materials. The insulating layer positioned between the first wiring layer and the second wiring layer is made of glass epoxy resin (FR-4), but it 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 forming the insulating layer, and the copper forming the first wiring pattern 11, the second wiring pattern 21, and the pattern 31 is, for example, They are 0.0241, 0.45 and 403 [W/(m·K)] in order of description.

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

In this modification, the first wiring pattern 11 has a third heat transfer portion 12c extending from the first terminal 10 toward the second terminal 20 in the third wiring layer, and the second wiring pattern 21 has a third heat transfer portion 12c. The fourth wiring layer has a third heat transfer portion 22c extending from the second terminal 20 toward the first terminal 10, and the third heat transfer portion 12c of the first wiring pattern 11 and the third heat transfer portion 22c of the second wiring pattern 21 are connected to each other. The heat transfer portion 22c faces each other. Further, in this modification, the first wiring pattern 11 has a fourth heat transfer portion 12d extending from the first terminal 10 toward the second terminal 20 in the fourth wiring layer, and the second wiring pattern 21 has , a fourth heat transfer portion 22d extending from the second terminal 20 toward the first terminal 10 in the third wiring layer; The fourth heat transfer portion 22d faces each other.

Furthermore, 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 a heat transfer portion of the first wiring pattern 11 as a wiring pattern connected to a terminal farther from the heat source 2 has the first extension portion 13a. However, instead of or in addition to this, as in the modification shown in FIG. The second heat transfer portion 12b as a may have a second extension portion 13b as another extension portion.

The above-described embodiment is merely an example of the present disclosure, and it goes without saying that various modifications are possible.

For example, the configuration may be such that 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 are not provided. The first heat transfer portion 12a of the first wiring pattern 11 may be configured without the first extension portion 13a. A configuration in which the slit 4 is not provided in the circuit board 1 may be adopted. A heat source 2 having a different distance to the first terminal 10 and a distance to the second terminal 20 may be arranged separately from the circuit board 1 . A configuration in which the pattern 31 is not provided with the extending portion 32 may be adopted. A configuration in which the pattern 31 does not extend beyond the slit 4 from the first terminal 10 side to the heat source 2 side may be employed. A configuration in which the pattern 31 is not provided on the circuit board 1 may be adopted. The circuit board 1 can also be applied to devices other than temperature measuring devices, such as temperature calibrator, various measuring devices, calibrator, and the like.

Reference Signs List 1 circuit board 2 heat source 3 heat transfer material 4 slit 10 first terminal 11 first wiring pattern 12a first heat transfer portion 12b second heat transfer portion 12c third heat transfer portion 12d fourth heat transfer portion 13a first extension 13b Second extension part 20 Second terminal 21 Second wiring pattern 22a First heat transfer part 22b Second heat transfer part 22c Third heat transfer part 22d Fourth heat transfer part 31 Pattern 32 Extension 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 toward the second terminal in 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 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 toward the second terminal in the other 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;
2. The circuit board according to claim 1, wherein said another heat transfer portion of said first wiring pattern and said another heat transfer portion of said second wiring pattern face each other. 3. The circuit board according to claim 1, further comprising heat sources having different distances from said first terminal and from said second terminal. 4. The circuit board of claim 3, having a slit located between the terminal closer to the heat source and the heat source. 5. The circuit board according to claim 3 or 4, having a pattern located between the terminal farther from the heat source and the heat source. the heat transfer portion of the wiring pattern connected to the terminal farther from the heat source has an extension portion extending toward the heat source beyond the terminal closer to the heat source; The circuit board according to any one of claims 3-5. Having the circuit board according to any one of claims 1 to 6,
A temperature measuring instrument that measures temperature via the thermocouple by connecting the thermocouple to the first terminal and the second terminal.

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