JP2000091714A - Temperature adjusting structure for printed board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature adjusting structure for printed board which can prevent the temperature drift of electronic parts, particularly, in a cold district and uses a smaller number of parts. SOLUTION: Since electronic parts 3 which are mounted on the printed board 1 of electronic equipment by reducing the number of parts can be maintained at a required temperature by sticking or printing a planar self-controlling positive temperature coefficient heating element 5 to or on the printed board 1 and energizing the heating element 5, the temperature drift of the parts 3 can be prevented, particularly, in a cold district. It is also possible to use a printed board composed of a planar self-controlling positive temperature coefficient heating element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature adjustment structure for a printed circuit board mounted on an electronic device, and more particularly to a temperature adjustment structure for adjusting the temperature of various electronic components mounted on a printed circuit board.

[0002]

2. Description of the Related Art Generally, a large number of various electronic components such as integrated elements are mounted on a printed circuit board mounted on an electronic device. Such electronic components may malfunction if the temperature of the electronic components changes due to heat generation or the like. Such a change in the temperature of the electronic component may hinder the extension of the life of the electronic component itself. Therefore, various devices have been conventionally devised to adjust the temperature of various electronic components mounted on a printed circuit board to a required temperature.

[0003] For example, there is a structure in which the temperature of a printed circuit board is adjusted by a forced air cooling method as in a printed circuit board temperature adjusting structure shown in FIG. In this temperature adjustment structure, a high heating element (high heat generation electronic component) 22 and a low heat generation element (low heat generation electronic component) 23 are arranged at predetermined positions on the surface of a printed circuit board 21, respectively. High heating element 22 and low heating element 2
A plurality of partition plates 24 are provided to adjust the cooling air volume by dividing the three. An air flow adjusting piece 25 is provided at one end of the partition plate 24 so that cooling air according to the heat generated by the high heating element 22 and the low heating element 23 is supplied to each heating element. Further, the temperature adjustment structure includes a cooling member including a fan, a duct, and the like (not shown), and sends cooling air to the printed circuit board 21.

In the structure for adjusting the temperature of a printed circuit board shown in FIG. 3, a predetermined amount of cooling air is sent to a printed circuit board 21 from a cooling member constituted by a fan, a duct and the like (not shown). A large amount of cooling air is supplied, and a small amount of cooling air is supplied to the low heating element 23. Therefore,
The temperature adjustment structure of the printed circuit board shown in FIG. 3 can adjust the temperature corresponding to the temperature of each heating element.

On the other hand, the temperature adjustment structure of a printed circuit board shown in FIG. 4 is a temperature adjustment structure of a type that dissipates heat using a heat sink. As shown in FIG. 4, such a temperature adjustment structure includes a printed board 31, an electronic component 32 disposed on the surface of the printed board 31, an electrical pin 33, and a heat sink adhered to the electronic component 32 in a state of being in close contact therewith. 34. The heat sink 34 is formed of a high heat conductor having good heat conduction. With the above configuration, the electronic component 3 is not provided in the printed board temperature adjustment structure shown in FIG.
2 generates heat from the electronic component 32 to the heat sink 34.
And the heat is dissipated into the air by the heat sink 34, whereby the temperature of the electronic component 32 is adjusted.

[0006]

However, the above-described temperature adjustment structure for a printed circuit board has the following problems. That is, in the printed circuit board temperature adjustment structure shown in FIG. 3, a cooling member composed of a fan, a duct, and the like is required to send cooling air to the printed circuit board. This not only increases costs due to an increase in the number of parts, but also increases costs. Particularly, in the case of a printed circuit board built in a small-sized electronic device, this has been a factor that hinders the desired size reduction of the temperature adjustment structure. Also,
As described above, the temperature adjustment structure of the printed circuit board shown in FIG. 3 can adjust the temperature corresponding to the temperature of each electronic component. However, it is not easy to finely adjust the air volume, and each electronic component has a required temperature. There was a limit to efficient adjustment.
In addition, since the temperature of each electronic component is adjusted by the cooling air, it has been difficult to accurately adjust the temperature of each electronic component having a different temperature. Furthermore, when the temperature of a place where an electronic device or a device in which a printed circuit board is incorporated and a device is used, that is, the environmental temperature changes, the temperature of electronic components on the printed circuit board changes in accordance with the environmental temperature. It has been difficult to adjust the electronic components to the required temperature. In particular, when electronic devices and devices with a built-in printed circuit board are used in a cold place, each electronic component on the circuit board causes errors in display values, indicated values, etc. due to changes in environmental temperature, that is, temperature drift. In some cases it occurred.

On the other hand, in the printed circuit board temperature adjustment structure shown in FIG. 4, it is possible to reduce the number of components, but it still requires the heat sink 33 and its heat radiation space. There was a limit. Further, in the printed board temperature adjustment structure shown in FIG. 4, it is necessary to individually provide the heat sink 34 for each electronic component in order to adjust the temperature corresponding to the temperature of each electronic component. In addition, since the temperature of each electronic component is adjusted by heat radiation, it has been difficult to accurately adjust the temperature of each electronic component having a different temperature. Furthermore, as in the case of the printed circuit board temperature adjustment structure shown in FIG. 3, when an electronic device or device having a built-in printed board is used in a cold place, each electronic component on the board is subject to environmental temperature changes. In some cases, errors in display values, indicated values, and the like, that is, temperature drift may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and reduces the number of components, saves space, and accurately and easily adjusts the temperature of electronic components on a substrate. It is an object of the present invention to provide a temperature adjustment structure of a printed circuit board that can easily prevent a temperature drift of an electronic component in a cold place.

[0009]

According to the first aspect of the present invention, there is provided a temperature control structure for a printed circuit board provided in an electronic apparatus, which is provided with a planar self-control type positive temperature coefficient. A temperature adjustment structure for a printed circuit board, wherein a heating element is attached.

The self-control type positive temperature coefficient heating element is a heating element having the property that, when energized, the electrical resistance of the heating element increases as the temperature of the heating element increases. Generally, when a current flows through a resistor, the resistor generates heat. However, the self-control type positive temperature coefficient heating element has a property that the electrical resistance rapidly increases at a certain temperature.
Therefore, when the self-controlled positive temperature coefficient heating element reaches a certain temperature, the current flowing is controlled and maintained at that temperature. That is, the self-control type positive temperature coefficient heating element is a heating element capable of controlling the heating temperature by itself.

Accordingly, a plurality of electronic components having different temperatures mounted on the printed circuit board can be easily mounted by applying a planar self-control type positive temperature coefficient heating element to the printed circuit board mounted on the electronic device and supplying current thereto. Since the required temperature can be maintained, temperature drift of the electronic component can be easily prevented when using an electronic device or device having a built-in printed board in a cold place. In addition, since the self-control type positive temperature coefficient heating element has a planar shape and can be attached to a printed circuit board, space efficiency can be improved.

The second temperature adjustment structure for a printed circuit board according to the present invention, which is provided to solve the above-described problems, prints a planar self-control type positive temperature coefficient heating element on a printed circuit board mounted on an electronic device. This is a printed circuit board temperature adjustment structure characterized by the following.

By printing a planar self-controlling positive temperature coefficient heating element on a printed circuit board mounted on an electronic device and applying a current to the printed circuit board, a plurality of electronic components having different temperatures mounted on the printed circuit board can be easily heated to a required temperature. Therefore, when using an electronic device or device having a built-in printed circuit board in a cold place, temperature drift of the electronic component can be easily prevented. Further, by making the shape of the self-control type positive temperature coefficient heating element planar and printing it on a printed circuit board, it is possible to further improve the space efficiency.

Further, in the third temperature control structure of a printed circuit board according to the present invention, which is provided to solve the above-mentioned problem, the printed circuit board mounted on the electronic device is formed of a planar self-control type positive temperature coefficient heating element. This is a printed circuit board temperature adjustment structure.

Since the printed circuit board mounted on the electronic device is composed of a planar self-control type positive temperature coefficient heating element, similar to the temperature adjustment structure of the first and second printed circuit boards of the present application, the electronic component can be used. Not only can temperature drift be easily prevented, but also space efficiency can be improved, and thermal conductivity to electronic components mounted on a printed circuit board can be improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a printed circuit board temperature adjusting structure according to the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view showing a component mounting surface of a printed circuit board temperature adjusting structure according to an embodiment of the present invention, and FIG. 2 is a circuit wiring pattern surface of the printed circuit board temperature adjusting structure according to an embodiment of the present invention. It is a perspective view.

As shown in FIG. 1, a through hole 4 for mounting an electronic component 3 such as an IC is provided on a component mounting surface 2 of a printed circuit board 1, and is provided at a position other than the position where the through hole 4 is provided. A planar self-control type positive temperature coefficient heating element 5 is printed. The through holes 4 are provided as appropriate for the electronic components 3 to be used. Further, the through hole 4 is subjected to an insulation treatment so as to be electrically insulated from the foot 6 of the electronic component 3 to be mounted. Also, electronic components 3
Each of the feet 6 is electrically connected to a circuit wiring pattern 8 provided on a wiring pattern surface 7 which is a back surface of the component mounting surface 2 as described later.

The self-control type temperature coefficient heating element 5 printed on the printed circuit board 1 has a heating element 9 made of conductive resin.
And a positive wiring pattern 10 connected to the positive electrode of a power supply (not shown) and serving as an electrode; and a negative wiring pattern 11 similarly connected to the negative electrode of the electrode (not shown) and serving as an electrode.
It is composed of As shown in FIG. 1, the positive electrode wiring patterns 10 and the negative electrode wiring patterns 11 are alternately arranged at a fixed distance so as not to contact each other. The heating element 9 is printed without any gap between the positive wiring pattern 10 and the negative wiring pattern 11. As mentioned above,
Since the through hole 4 is electrically insulated from the foot 6 of the electronic component 3 to be mounted, the foot 6 of the electronic component 3 and the heating element 9
Are insulated, and the foot 6 of the electronic component 3 and the positive wiring pattern 10
The negative wiring pattern 11 is also insulated.

When the self-control positive temperature coefficient heating element 5 is energized, the temperature of the heating element 9 rises as the temperature of the heating element 9 rises.
Is a heating element having the property of increasing the electrical resistance of the heating element. Generally, when a current flows through a resistor, heat is generated. However, the self-controlling positive temperature coefficient heating element 5 has a property that the electrical resistance rapidly increases at a certain temperature. Therefore, the self-control type positive temperature coefficient heating element 5
When a certain temperature is reached, the current flowing is controlled and maintained at that temperature. That is, the self-control type positive temperature coefficient heating element 5
Is a heating element that can control the heating temperature by itself. Further, since the heating temperature is determined by the heating element 9, it can be set to a required temperature.

As shown in FIG. 2, a soldering land 12 for the electronic component 3 is provided around the through hole 4 on the wiring pattern surface 7 which is the back surface of the printed circuit board 1. A circuit wiring pattern 8 corresponding to the component 3 is provided. The plurality of electronic components 3 are electrically connected by connecting the circuit wiring pattern 8 to the feet 6 of each of the electronic components 3.

With the above structure, in the printed board temperature adjusting structure according to the present embodiment, the heating element 9 is heated to a set temperature, for example, 20 ° C. by energizing the positive wiring pattern 10 and the negative wiring pattern 11. . The heat generating portion is the heat generating element 9 within a range of an area represented by A × B in FIG. 1, that is, a range surrounded by the positive wiring pattern 10 and the negative wiring pattern 11. Then, the heat generated in the heating element 9 is conducted to the electronic component 3, and the electronic component 3 is maintained at the set temperature. As described above, in the present embodiment, by using the self-controlling positive temperature coefficient heating element 5, all of the plurality of electronic components 3 having different heating states can be accurately and easily maintained at the set temperature. Further, in the present embodiment, by maintaining the electronic component 3 at the set temperature, an electronic device in which the printed circuit board 1 is built in a cold place,
When using the device, the temperature drift of the electronic component 3 can be prevented. Furthermore, by making the shape of the self-controlling positive temperature coefficient heating element 5 planar and printing it on a printed circuit board, it is possible to improve the space efficiency.

In the structure for adjusting the temperature of a printed circuit board according to this embodiment, a conductive resin is used as the heating element 9, but carbon or the like may be used. Also,
The arrangement of the positive wiring pattern 10 and the negative wiring pattern 11 is not limited to the arrangement shown in the present embodiment, but it is desirable to provide an appropriate wiring pattern according to the arrangement of the electronic components 3 to be used.

In the temperature adjustment structure for a printed circuit board according to the present embodiment, the self-controlling positive temperature coefficient heating element 5 is printed on the printed circuit board 1, but the self-controlling positive temperature coefficient heating element is made of an insulator. It may be covered and attached to a printed circuit board. In addition, in the case of using a laminated printed circuit board, a self-controlled positive temperature coefficient heating element covered with an insulator can be interposed between the laminated printed circuit boards. Further, the printed circuit board itself can be used as a self-control type positive temperature coefficient heating element.

As described above, the printed circuit board having the temperature adjusting structure according to the present embodiment can prevent the temperature drift of the electronic component 3 in a cold place and can reduce the space. Therefore, it is suitable to be used in electronic devices that are used in cold places and that require miniaturization and high precision, such as electronic thermometers and ear-type radiation thermometers, which are medical devices used outdoors during disasters.

[0025]

As described above, the printed circuit board temperature adjustment structure according to the present invention is obtained by attaching or printing a planar self-control type positive temperature coefficient heating element to a printed circuit board mounted on an electronic device. By applying a current, it is possible to accurately and easily maintain a plurality of electronic components mounted on the printed circuit board at different temperatures at a required temperature. In use, temperature drift of the electronic component can be easily prevented. In addition, by making the shape of the self-controlling positive temperature coefficient heating element planar, the self-controlling positive temperature coefficient heating element can be attached or printed on a printed circuit board, so that space efficiency can be improved.

Further, the printed board temperature adjusting structure according to the present invention is characterized in that the printed board mounted on the electronic device is formed of a planar self-control type positive temperature coefficient heating element.
Not only can the temperature drift of the electronic component be prevented, but also the space efficiency can be improved, and the thermal conductivity to the electronic component mounted on the printed circuit board can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a component mounting surface of a temperature adjustment structure of a printed circuit board according to an embodiment of the present invention.

FIG. 2 is a perspective view illustrating a circuit wiring pattern surface of a temperature adjustment structure of a printed circuit board according to an embodiment of the present invention.

FIG. 3 is a perspective view showing a conventional printed circuit board temperature adjustment structure.

FIG. 4 is a cross-sectional view illustrating a conventional printed circuit board temperature adjustment structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Printed circuit board 2 ... Component mounting surface 3 ... Electronic component 4 ... Through hole 5 ... Self-control type positive temperature coefficient heating element 6 ... Feet 7 ... Wiring pattern surface 8 ... Circuit wiring pattern 9 ... Heating element 10 ... Positive wiring pattern 11 … Negative wiring pattern 12… Soldering land 21… Printed board 22… High heating element 23… Low heating element 24… Partition plate 25… Air flow adjusting piece 31… Printed circuit board 32… Electronic components 33… Electric pins 34… Heat sink

Claims (3)

[Claims] 1. A printed circuit board mounted on an electronic device,
A temperature adjustment structure for a printed circuit board, wherein a planar self-control type positive temperature coefficient heating element is attached. 2. A printed circuit board mounted on an electronic device,
A temperature adjustment structure for a printed circuit board, wherein a planar self-control type positive temperature coefficient heating element is printed. 3. A temperature adjustment structure for a printed circuit board, wherein the printed circuit board mounted on the electronic device comprises a planar self-control type positive temperature coefficient heating element.