JPS5929359Y2 - Heating element device using positive temperature coefficient thermistor - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a heating element device using a positive temperature coefficient thermistor.

Generally, in a heating element using a positive temperature coefficient thermistor, it is desirable for the equivalent center point of the generated heat to be located as close to the surface side as possible from the viewpoint of rapid heating, detection of ambient temperature, and other aspects.

Therefore, conventionally, a positive temperature coefficient thermistor having an electrode shape as shown in FIG. 1 has been devised.

First electrodes 2 forming power supply terminals provided at opposite ends of one plane of the positive temperature coefficient thermistor substrate 1
, 3, and a plurality of finger-shaped second electrodes 4.5 connected to each of the first electrodes 2, 3 and extending in parallel at regular intervals alternately forming a heat generating part. A large amount of current is passed between the second electrodes 4 and 5 on the surface side of the substrate 1 to generate heat.

In a heating element device having such an electrode configuration, when a voltage is applied to the device, the power terminals connected to the power supply side are brought into contact with the first electrodes 2 and 3, or the substrate 1 This has been done by forming a third electrode forming an extraction terminal connected to the first electrodes 2 and 3 on the back surface, and bringing a power supply terminal into contact with this third electrode.

However, when bringing the power supply terminal into contact with the first electrodes 2 and 3, the width of the first electrodes 2 and 3 (
Part a) must be provided to be somewhat wide, and as a result, the electrode portion that does not directly contribute to heat generation increases, and the effective heat generation area of the substrate 1 becomes narrower.

Also, when providing a third electrode for contacting the power terminal on the back surface of the substrate 1, this third electrode is used to ensure stable contact.
The width of the electrode (width in the same direction as part a of the first electrodes 2 and 3) must be made wide to some extent, and as a result, this third electrode and the heat generating part on the surface of the substrate 1 are formed. Among the second electrodes 4 and 5, which are located at positions corresponding to the respective third electrodes, a current in the thickness direction flows between the electrodes having a different potential, and the substrate 1 is thin. In this case, sufficient withstand voltage cannot be obtained.

In order to prevent such a drop in withstand voltage, either the thickness of the substrate 1 should be made sufficiently thick, or a part of the second electrode through which current flows in the thickness direction of the substrate 1 should be connected between the third electrode and the second electrode. 4,5
If the length of the second electrodes 4 and 5 is made shorter than that of the other second electrodes 4 and 5, the current can be prevented from flowing in the thickness direction.
The heat generated on the surface side of the substrate 1 is also absorbed inside the substrate 1, making it impossible to effectively heat the object to be heated. The effective heat generating area of the plane becomes narrower.

Further, in the case of a so-called single-sided heating type in which only one plane of the substrate 1 generates heat, such a third electrode can be provided, but in the case of a so-called double-sided heating type in which heat is generated on a side plane of the substrate 1, Such a third electrode cannot be provided.

In any case, with conventional voltage application means, it is not possible to reduce the thickness of the substrate 1, or it is not possible to maximize the effective heat generation area of the 1,000 surfaces of the substrate, resulting in poor heating efficiency. It was bad.

The present invention was made in consideration of these points, and
It is an object of the present invention to provide a heating element device using a positive temperature coefficient thermistor which has a thin substrate and can maximize the effective heat generating area on the plane of the substrate and has good heating efficiency.

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

In FIG. 2, 11 is a positive temperature coefficient thermistor substrate, 12.
13 is a first plate provided at opposite ends of the plane of this substrate 11.
The electrodes 12a, 13a are on opposite side surfaces of the substrate 11,
The extraction electrodes 14.15 forming power supply terminals connected to the first electrodes 12.13 have one end connected to the first electrode 12.13, and the other end connected to the other first electrode 14.15. A plurality of finger-shaped second electrodes are arranged alternately to face the electrodes and constitute a comb-shaped heating section.

Reference numerals 16 and 17 designate lead terminals that are soldered 18 in contact with extraction electrodes 12a and 13a formed on opposing side surfaces of the first electrodes 12 and 13 of the substrate 11, respectively.

In this case, each lead terminal 16.17 is connected to the substrate 1.
1 so that it does not protrude above the same area of the substrate 11, and allows a heat sink, a heated body, etc. (none of which are shown) to be placed in close contact with the entire heat generating surface of the substrate 11. I'm trying to make it possible.

Of course, it is also necessary to prevent the solder 18 for bonding from protruding from the surface of the substrate 11.

At least the lead terminal 12a of the lead terminal 16.17
.

It is only necessary to prevent the contact portion with the substrate 13a from protruding from the surface of the substrate 11.

The heating element device configured in this way has lead terminals 16.
A power terminal is connected to 17 and a voltage is applied, and the surface side of each substrate 11 between the second electrodes 14 and 15 generates heat.
Good low thermal resistance, acts as a heating element device.

Note that, as in the above embodiment, the extraction electrode 12a.

When the electrode 13a is provided over the entire side surface of the substrate 11, it may have the function of the first electrode, so the first electrodes 12 and 13 are not necessarily required.

On the contrary, the first electrode 12.
13, the extraction electrode 12a on the side surface thereof,
13a should have at least the area necessary to provide the lead terminals 16 and 17.

Furthermore, the connection of the lead terminals 16 and 17 is not limited to soldering as in this embodiment, but may be welded, bonded with a conductive adhesive, or pressure-bonded by its own elasticity or pressure-bonded by another elastic body. , any means may be used, and the shapes of the lead terminals 16, 1γ are not limited to those shown in the drawings.

Further, the second electrode 14.15 forming the heat generating part is connected to the substrate 1.
It is also optional to provide a double-sided heating type by providing the same area on both sides of the substrate.In this case, the second electrode 14°
5, if the same potential is placed in the thickness direction of the substrate 11, almost no current will flow in the thickness direction of the substrate 11, so even if the thickness of the substrate 11 is thin, the withstand voltage characteristics will deteriorate. Never.

As explained above, in the present invention, a comb-shaped second electrode that forms a heat generating part is provided on the plane of the PTC thermistor substrate, and heat is generated on the surface side of the substrate, so the temperature distribution on the heat generating surface. This has the effect of making it extremely small and increasing the effective heat generating area.

In addition, in the present invention, the voltage is applied to the board via the lead terminal at the nine electrodes provided on the side surface of the board, and the lead terminal is not protruded from the board surface, so that the current in the thickness direction of the board is reduced. As a result, the thickness of the board can be reduced, and the electrodes that do not directly contribute to heat generation on the board surface can be minimized or completely eliminated, resulting in an effective use of the board surface. Now we can maximize the heat generating area,
This results in a good heating element device with good heating efficiency.

[Brief Description of the Drawings] Fig. 1 is a perspective view of a heating element device using a conventional PTC thermistor, and Fig. 2 is a perspective view of a heating element device using a PTC thermistor according to an embodiment of the present invention. be. 11... Positive temperature coefficient thermistor board, 12, 13...
...First electrode, 14.15...Second electrode, 16°17...Lead terminal, 12a, 1
3a... Extraction electrode.

Claims (1)

[Scope of utility model registration request] A positive temperature coefficient thermistor substrate, an extraction electrode provided on opposite side surfaces of the positive temperature coefficient thermistor substrate, and an extraction electrode provided on the opposite side surface on one plane or circumferential plane of the positive temperature coefficient thermistor substrate, A plurality of elongated electrodes are provided in a comb-like shape such that one end thereof is electrically connected to the other electrode and the other end is opposed to the other extraction electrode, and each of the electrodes is in contact with each of the extraction electrodes. The thickness of the lead terminal at least at the contact portion of the extraction electrode and its vicinity is made smaller than the thickness of the substrate so that the lead terminal does not protrude onto both planes of the substrate. A heating element device using a characteristic thermistor, characterized in that an object to be heated is thermally disposed on at least one plane of the substrate.