JP2000311541A - Key switch device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent electrical conduction failures caused by deteriorated contacts and increased contact resistance due to an increased number of keyings. SOLUTION: A current generated in a current generating circuit 103 is passed through a coil A102 attached to a key cap 101 to set up a magnetic field by electromagnetic induction. When the key cap 101 is depressed to come closer to a coil B104 formed on a key bottom part, the magnetic field set up by the coil A102 causes an electromotive force to be generated in the coil B104 by electromagnetic induction, Then, a current generated in the coil B104 is detected by a current detection circuit 105 installed in the exterior, and thus the depression of this key switch can be detected, When the key switch returns to its original position, the electromotive force in the coil B104 is eliminated, and thus it can be decided that the key switch is not in a depressed state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a key switch device, and more particularly, to a key switch device constituting a keyboard for inputting information from the outside to information equipment and the like.

[0002]

2. Description of the Related Art A conventional key switch constituting a keyboard or the like detects a pressed information by energization by physical contact, and has a key cap 301 and a conductive rubber contact 302 as shown in FIG. Cup-shaped rubber 303 and contact A3
04 and a contact B305, and the keycap 3
01, the cup-shaped rubber 303 is deformed, the conductive rubber contact 302 moves downward, and the contact A 304 and the contact B
When the key switch is released and the pressing force is removed by physically contacting the key cap 305, the key cap 301 is electrically connected to the key cap 301 by the force to return to the original shape. The rubber 302 moves upward and returns to the original non-pressed state, and the cup-shaped rubber 303 is a mechanical spring or a contact A30.
4. The contact B 305 has a membrane structure.

[0003]

However, in the conventional key switch device, since pressing is detected by electrical conduction due to physical contact between the key top portion and the key bottom portion, if dust such as dust adheres to the contact portion. , Electrical conduction is lost, pressing can not be detected, and pressing detection is performed by electrical conduction due to physical contact between the key top and key bottom, so the number of keystrokes increases and the contact resistance increases due to the deterioration of the contacts Contact failure occurs, electrical continuity is lost, and pressing cannot be detected.

[0004]

In order to solve the above-mentioned problems, a key switch device according to the present invention is provided with a coil in a key top portion and a key bottom portion, and a current is supplied to one of the coils to generate a key. While the key is pressed, the above-mentioned coils are close to each other and generate a potential due to electromagnetic induction in the other coil, and while the key is not pressed, the above-mentioned coils are separated and a potential due to electromagnetic induction is generated in the other coil. It is characterized by comprising a key switch that is not allowed to operate and a detection circuit that detects a potential due to electromagnetic induction generated from the key switch.

[0005]

Next, a key switch device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a conceptual diagram of a key switch device according to an embodiment of the present invention.

FIG. 2 shows a configuration example of an upper coil of a key switch device according to an embodiment of the present invention.

As shown in FIG. 1, a key switch device according to an embodiment of the present invention includes a key cap 101, an associated coil A102, a current generating circuit 103 for supplying a current to the coil A, and a key bottom. It comprises a coil B104 thus configured and a detection circuit 105 for detecting a flowing current.

FIG. 2 shows an example of the configuration of the upper coil.
As shown in the figure, a keycap 201, a coil A202 wound around a shaft associated therewith, a current generation circuit 203
And a leaf spring or a pantograph 204.

Next, the operation of the key switch device according to one embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the operation concept of the key switch device according to the embodiment of the present invention is as follows. First, a current generated by a current generating circuit 103 flows through a coil A 102 attached to a key cap 101. Coil A102
Generates a magnetic field due to electromagnetic induction when a current flows. Here, when the keycap 101 is pressed down and approaches the coil B104 formed on the key bottom portion, the magnetic field generated from the coil A101 causes the coil B102 to move.
A magnetic field is induced in the device, and an electromotive force is generated. Thus, the current generated in the coil B102 is detected by the current detection circuit 105 provided outside. Therefore, here, it can be detected that this key switch has been pressed.

When this key switch is not pressed and the position of the key cap 101 returns to the original position, the distance between the coil A 102 and the coil B 104 is increased, the coil B 104 has no electromotive force, and the current detection circuit 105 terminates the detection. It can be determined that the key switch is no longer pressed.

As a specific configuration example of the keycap portion, as shown in FIG. 2, a wiring from the current generating circuit 203 is connected to a leaf spring or a pantograph 205 for generating a stress for pushing the keycap 201 upward. Through the coil A202. As a result, the wiring from the current generation circuit 203 passes through the keycap 21 through the air.
0 is not wired to the coil A202,
A simple configuration can be achieved.

[0014]

As described above, according to the key switch device of the present invention, the pressing operation is detected by the current generated by the electromagnetic induction by the coils provided at the key top and the key bottom. No contact. Therefore, even if dust such as dust adheres to the contact portion, the contact can be detected because the contact is non-contact, and there is no physical contact. This has the effect of preventing a touch detection failure due to a contact failure occurring due to the occurrence of electrical contact and loss of electrical conduction.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a key switch device according to an embodiment of the present invention.

FIG. 2 is a configuration example of an upper coil of the key switch device according to the embodiment of the present invention.

FIG. 3 is a configuration example of a conventional key switch device.

[Explanation of symbols]

 1, 101, 201, 301 Keycap 2, 102, 202 Coil A 3, 103, 203 Current generation circuit 4, 104 Coil B 5, 105 Current detection circuit 6, 204 Leaf spring or pantograph 7, 302 Conductive rubber contact 8 , 303 Cup rubber 9,304 Contact A 10,305 Contact B

Claims (1)

[Claims] A coil is provided in a key top portion and a key bottom portion, and while a key is being pressed, the coils are close to each other and are electromagnetically induced to the other coil by a current flowing through one of the coils. A key switch that separates the coils so as not to generate a potential due to electromagnetic induction in the other coil while the key is not pressed, and a detection circuit that detects a potential due to electromagnetic induction generated from the key switch. A key switch device comprising: