JPH02837Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a reed relay, and more particularly to a low thermal electromotive force type reed relay.

A conventional example of a reed relay is shown in FIG. In FIG. 1, 10 is a reed switch. This reed switch is constructed by enclosing a pair of reed pieces 11 and 12 made of a magnetic material such as permalloy in a glass tube 13. Reference numeral 20 denotes a coil wound around the reed switch 10, and a contact 14 made up of reed pieces 11 and 12 is closed (or opened) by a magnetic field generated by exciting this coil. Note that the coil 20 may be replaced with a permanent magnet. 31 and 32 are lead terminals made of steel, respectively. The lead terminal 31 is connected to the lead piece 11 at a connection point A, and the lead terminal 32 is connected to the lead piece 12 at a connection point B by welding, soldering, or the like. A case 40 is made of an insulating material, and the reed switch 10 and the coil 20 are arranged inside this case. The lead terminals 31 and 32 penetrate the side surface of the case 40 and are drawn out.

Such reed relays have been widely used in the past, but they have lead pieces 11, 12, lead terminals 31,
32 are different metals, so if a temperature difference occurs between the connection points A and B due to the heat generated when the coil 20 is excited, the temperature difference between the lead terminals 31 and 32 will change depending on the temperature difference. Thermoelectromotive force is generated. In particular, since permalloy with a large thermoelectromotive force is often used for the lead pieces 11 and 12, the thermoelectromotive force reaches approximately several +μV per degree Celsius. For that reason,
The reed relay shown in FIG. 1 cannot be applied as it is to a circuit that is expected to have high accuracy, such as switching minute signals.

FIG. 2 is a diagram showing a conventionally known reed relay as a low thermal electromotive force type improved to reduce the thermal electromotive force as described above. In Figure 2, 50
is a thermal balance element. This thermal balance element is made of ceramic or the like with good thermal conductivity. The lead piece 11 and the lead terminal 31 are connected at point A, and the lead piece 12 and the lead terminal 32 are connected at point B, and the connection points A and B are fixed to this thermal balance element via a thermal balance element 50. ing.

In the reed relay shown in FIG. 2 having such a configuration, the connection points A and B are thermally equalized by the thermal balance element 50, so the thermoelectromotive force generated at the connection points A and B is canceled out, and the voltage between the lead wires 31 and 32 is The thermoelectromotive force generated in this case is reduced. The reed relay shown in FIG. 2 is of a low thermal electromotive force type and is used in high-precision circuits that switch minute signals. This makes the structure complicated and the volume of the relay large.

(2) Man-hours are required for manufacturing due to the complex structure. Moreover, as a result, the product value increases.

(3) Due to internal structure, lead terminals 31 and 3
2 protrudes from the side of the case 40, so it is not practical to attach it to a printed board.

There are drawbacks such as. The present invention realizes a low thermal electromotive force type reed relay that improves these drawbacks, and an embodiment thereof is shown in FIG. In FIG. 3, the same elements as in FIG. 1 are given the same reference numbers as in FIG. 1, and their redescription will be omitted.

In FIG. 3, 60 is a substrate. This substrate is made of ceramics (alumina, steatite, etc.) that have better thermal conductivity and high insulation properties than, for example, general baked plates. 70 and 80 are copper patterns formed on the substrate 60, respectively. One end surface 71 and 81 of each of the patterns 70 and 80 has a slight gap (1 in the embodiment).
They are formed on the substrate 60 so as to face each other with a distance of m/m). The end surfaces 71 and 81 of the patterns 70 and 80 may be arranged to face each other on the same surface of the substrate 60 as shown in FIG. 4A, or on opposite surfaces as shown in FIG. 4B. Lead pieces 11 and 1
2 is bent, and both ends are patterned 70 and 8.
Points A and B on one end surface 71 and 81 of 0 are connected to this pattern by soldering. Terminals 91 and 92 are provided on the substrate 60 so as to pass through the substrate, and the terminal 91 is connected to the end 72 of the pattern 70, and the terminal 92 is connected to the end 82 of the pattern 80, respectively. A substrate 60 is used for the lower surface of the case 40. terminals 91 and 92
This is convenient when using the present reed relay as a mounting means for attaching it to another printed circuit board (not shown).

The basic operation of the reed relay of the present invention having such a configuration is the same as that shown in FIG. Lead pieces 11 and 1 are attached to patterns 70 and 80, which are formed so that end surfaces 71 and 81 face each other with a slight gap between them.
2 are connected at points A and B, the connection points A and B are thermally equivalent. Therefore, the lead pieces 11, 12 and the patterns 70, 8
Even if 0 is a different material, the connection point A,
The thermoelectromotive force generated at B is canceled out, and the terminals 91 and 9
2, a contact signal with reduced thermal electromotive force can be obtained. The reed relay of the present invention, which has been improved to have a low thermal electromotive force, has the following effects compared to the low thermal electromotive force type reed relay shown in FIG.

(1) In the present invention, the built-in thermal balance element 50 in FIG. 2 is replaced by a pattern on the substrate 60, so the structure is simplified, the number of manufacturing steps is reduced, and extra space is unnecessary. As a result, a relay that is smaller and cheaper than that shown in FIG. 2 can be obtained.

(2) In the relay of the present invention, the position of the pattern on the board 60 can be arbitrarily determined as required, so it is particularly advantageous when used attached to a printed board. Also, unlike the method shown in Figure 2 where the lead wire comes out from the side of the case,
In the case of the printed board mounting type, the present invention has the advantage of reducing the size of the relay and increasing the packaging density.

FIG. 5 shows an embodiment of the present invention applied to a multi-contact reed relay (the case is omitted in the figure). Here, three-contact reed switches 10A, 10B,
The case where 10C is used is illustrated. pattern 7
0 and 80 are provided for each reed switch. The substrate 60 has good thermal conductivity as shown in FIG.
In addition, a highly insulating material is used. One end surface of each pattern 70 and 80 is formed on the substrate 60 so as to face each other with a slight gap, and each lead piece 1 of the reed switches 10A, 10B, 10C
1 and 12 are connected to one end of each pattern 70 and 80 at points A and B, respectively. Each of the connection points A and B is thermally equalized as described in FIG. 3, and the reed switches 10A, 10B, and 10C are each made to have a low thermal electromotive force as in FIG. 3.

[Brief explanation of drawings]

1 and 2 are block diagrams of conventional reed relays, FIG. 3 is a block diagram showing an embodiment of the reed relay according to the present invention, and FIG. 4 is a circuit board used in the reed relay of FIG. 3. Fig. 5 is a block diagram showing another embodiment of the reed relay according to the present invention. 10...Reed switch, 11, 12... Lead piece, 60... Board, 70, 80... Pattern.

Claims (1)

[Scope of utility model registration request] A ceramic substrate is formed with a pair of opposing patterns with one end surface separated by a small distance, and the contact portions connect both ends of lead pieces that respond to a magnetic field to one end surface of each of the patterns. The reed relay also includes a reed switch formed by connecting a terminal provided through the substrate to the other end surface of each of the patterns.