JPH079326Y2 - Reed relay - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an impedance matching type reed relay.

[Prior Art] A conventional reed relay has a configuration as shown in FIG.
A reed switch 2 is arranged in the center of a coil 1 formed in a substantially cylindrical shape, and the reed switch 2 is housed in a case, and the input / output ends of the coil 1 and the lead terminals 2d, 2e of the reed switch 2 are set in the case. The terminals are formed by being led out to the outside.

As is well known, the reed switch is constructed by enclosing a pair of reed pieces 2b, 2c made of a magnetic material in a glass tube 2a, and reed pieces are formed by a magnetic field generated by excitation of a coil. The configured contact 2f is adapted to be closed or opened.

Although such a reed relay has been used more frequently than before, when the coil 1 is excited, noise generated by induction leaks to the reed pieces 2b and 2c for switching the signal, and the signal is output together with the noise. Therefore, the reed relay shown in FIG. 1 could not be applied as it is to a circuit that expects high precision such as switching a minute signal or high frequency.

FIG. 2 is a block diagram showing a conventionally known reed relay as an electrostatic shield type which is improved so as to reduce the noise due to the induction as described above. In FIG. 2, 3 is an electrostatic shield, which is arranged between the coil 1 and the reed switch 2. The electrostatic shield 3 is a good conductor and is made of a cylindrical copper material.

In the conventional reed relay having such a configuration, the electrostatic capacitance between the coil 1 and the lead pieces 2b and 2c is reduced by disposing the electrostatic shield 3 between the coil 1 and the reed switch 2. Such a reed relay shown in FIG. 2 is used as a shield type reed relay in a highly accurate circuit for switching a minute signal or a high frequency.

[Problems to be Solved by the Invention] However, in the reed relay configured as described above,
There are the following inconveniences.

(1) As is well known, impedance matching is an important characteristic for switching high-frequency signals, but in order to raise the impedance, the electrostatic shield 3 should be placed at a sufficiently large distance from the lead pieces 2b, 2c. The outer circumference of the electrostatic shield must be large. Therefore, the volume becomes large. On the contrary, in order to lower the impedance, it is necessary to bring the electrostatic shield close enough to the lead piece contrary to the above, but there is a limit because of the glass tube 2a. That is, it is difficult to achieve various impedance matching.

(2) When the lead pieces 2b, 2c are closed or separated, an electromotive force is generated by the vibration of the lead pieces. Therefore, it cannot be applied to a circuit that expects high precision such as switching of ultra-small signals.

The present invention is intended to provide an impedance matching type reed relay in which such drawbacks are improved.

[Means for Solving Problems] In order to improve such drawbacks, the present invention connects the external contact conductors 4a and 4b to the lead terminals 2d and 2e of the conventional reed relay and connects the lead pieces 2b and 2c to the lead pieces 2b and 2c. Along the external contact conductors 4a, 4b
Is provided and is opposed to the electrostatic shield 3.

[Operation and Example] Hereinafter, the present example will be described in detail with reference to the drawings.
FIG. 4 and FIG. 4 are configuration diagrams of a reed relay showing an embodiment of the present invention, in which 1 is a coil, 2 is a reed switch, 2f is a contact portion thereof, and 2d and 2e are reed terminals. 3 is an electrostatic shield, which is arranged along the lead pieces 2b and 2c and has a cylindrical shape (see FIG. 3) surrounding the outer circumference of the external contact conductors 4a and 4b depending on the impedance level, or a semi-cylindrical cutout. , Or a flat plate (see FIG. 4).

The external contact conductors 4a, 4b are connected to the lead terminals 2d, 2e at the connection points 4c, 4d, are arranged along the glass tube 2a in parallel with the lead pieces 2b, 2c, and by the impedance matching high and low,
A cylindrical shape, a semi-cylindrical shape, or a flat plate shape is selected.

The basic operation of the reed relay of the present invention having such a configuration is the same as that of FIGS. 1 and 2, but impedance matching for switching a high frequency signal is as follows.
A small reed relay with unprecedented low impedance is realized by taking out the reed pieces 2b, 2c and the electrostatic shield 3 so that they are close to each other, and increasing the facing area with the electrostatic shield 3. did. Further, the electrostatic shield 3 is cut open, and the area of contact with the lead pieces 2b, 2c is reduced to reduce the electrostatic capacitance between the opposing conductors, thereby realizing high impedance.

That is, by providing the external contact conductors 4a and 4b, the capacitance between the electrostatic shields 3 is increased, and the electrostatic shields 3
By cutting open, the capacitance between the lead pieces 2b and 2c is reduced, and a small reed relay with low impedance and high impedance can be easily manufactured.

[Advantages of the Invention] According to the present invention having the above configuration, the following great effects are obtained.

(1) By providing the external contact conductor in which the lead piece is led to the outside of the glass tube, a low impedance matching type reed relay which cannot be obtained by the conventional reed relay can be easily obtained.

(2) By providing the cut-out electrostatic shield facing the lead piece, a high impedance matching type reed relay smaller than the conventional reed relay can be easily obtained.

(3) Since the external contact conductors connected to the lead terminals are provided, the electromotive force generated by the vibration of the lead piece at the time of closing or opening the contact is eliminated, so that the conventional reed relay cannot obtain it. It is easy to obtain a reed relay for use in a circuit that expects high precision such as switching ultra-small signals.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are configuration diagrams showing a conventional reed relay, respectively. FIG. 3 is a block diagram showing a reed relay according to the present invention, and FIG. 4 is a block diagram showing another embodiment of the reed relay according to the present invention. 1 is a coil 2 is a reed switch 3 is an electrostatic shield 4 is an external contact conductor

Claims (5)

[Scope of utility model registration request] 1. In a reed switch, a non-magnetic external contact conductor is opposed to and connected to a lead terminal along each of the lead pieces, and the external contact conductor and the electrostatic shield are installed so as to face each other. A reed relay characterized in that impedance matching is set according to the intended use depending on the size of the conductor. 2. A utility model registration claim characterized in that an electrostatic shield arranged facing the lead piece is cut open, and an external contact conductor for setting an impedance suitable for the intended use is cylindrical in size. The reed relay according to the first section. 3. A utility model registration request characterized in that an electrostatic shield arranged opposite to the lead piece is cut open, and an external contact conductor for setting an impedance suitable for the intended use depending on its size is plate-shaped. The reed relay according to the first section. 4. The utility model registration claim 1 characterized in that the electrostatic shield for setting the impedance suitable for the intended use by the size of the external contact conductor arranged facing the lead piece is cylindrical. Reed relay shown. 5. The utility model registration claim 1 characterized in that the electrostatic shield that sets the impedance suitable for the intended use by the size of the external contact conductor arranged facing the lead piece is plate-shaped. Reed relay shown.