JPH0644434B2 - Key switch device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a key switch device for equipment such as a microcomputer washing machine used in a general household.

2. Description of the Related Art Conventionally, in this type of key switch, as shown in FIG. 4, a switch matrix A is formed by a plurality of switches, and an output port of the microcomputer B, OUT0, OUT.
1, OUT2 are sequentially scanned to detect the input voltage of the input ports IN0, IN1 and IN2, and which key is pressed is recognized.

Problems to be Solved by the Invention In such a conventional configuration, since a switch having a normal contact is used, when the switch is applied to, for example, a washing machine, oxidation of the contact due to moisture or detergent or leakage due to water occurs, and There was a problem with reliability. Further, there are some which have improved the contact material and the switch structure in order to improve the reliability, but the price of the switch is high.

It is an object of the present invention to solve such conventional problems and provide a contactless and highly reliable key switch device.

Means for Solving the Problems In order to solve the above problems, the present invention is provided with a plurality of primary coils formed on a plate-like member and connected in series, and provided so as to face each primary coil. A plurality of series-connected secondary coils formed on a plate-like member, a spacer for arranging a pair of coils facing each other with a space distance, and a high-frequency output for supplying a high-frequency current to the primary coil. And an input unit for detecting a voltage induced in the secondary coil.

Operation With the above configuration, by sequentially scanning the high frequency output section and checking the voltage of the corresponding input section, 1
The distance between the secondary coil and the secondary coil, that is, whether the key is turned on or off is determined.

Embodiment FIG. 1 is a sectional view of a key switch showing an embodiment of the present invention. Reference numeral 1 is an operator's finger, and 2 is a spacer for mounting the plate-like member 3 which constitutes the elastic switch panel and the plate-like member 4 which is a printed circuit board with a space therebetween. Reference numeral 5 denotes a primary coil formed on the back surface of the plate-shaped member 2 in a plane, and 6 denotes a secondary coil formed on the plate-shaped member 4 in a plane. These primary and secondary coils are formed by providing conductive paint in a meandering shape.

FIG. 2 is a diagram showing a state of the spacer 2 and the secondary coil 6, and shows a state in which the key switch is viewed from above. As can be understood from this, the periphery of the secondary coil 6 is surrounded by the spacer 2 and is completely separated from the other secondary coils 6.

In the key switch having the structure as shown in FIG.
When the finger 1 is pressed, the primary coil 5 becomes the secondary coil 6
, The mutual coupling (electromagnetic coupling) is improved. That is, when the finger 1 is pressed, a high-frequency current flowing in the primary coil 5 induces a voltage in the secondary coil 6.
That is, one switch is configured.

FIG. 3 shows a circuit diagram in which the switches composed of a pair of coils described above are connected in a matrix. As shown in the figure, the plurality of primary coils 5 are respectively connected in series and are connected to the output ports OUT0 to OUT2 of the microcomputer 8. The output port of the microcomputer 8 constitutes a high frequency output section for supplying a high frequency current to the primary coil 5. The secondary coil 6 is similarly connected in series and connected to the input ports IN0 to IN2 of the microcomputer B. The input port of the microcomputer 8 constitutes an input section for detecting the voltage induced in the secondary coil 6.

Next, the operation will be described. Output port OUT of microcomputer B
High-frequency output is output sequentially from 0. At this time, when a certain switch in the matrix is pressed, electromagnetic coupling is improved only for that switch, so that a high frequency voltage is induced at the input port to which the switch is connected. The relationship between the output port and the input port where the voltage is generated tells which switch was pressed.

Reference numeral 8 is a diode, which is inserted to protect the input port.

EFFECTS OF THE INVENTION The key switch device of the present invention operates in a non-contact manner as compared with the conventional mechanical contact, and therefore has high reliability and does not malfunction due to moisture or detergent. Further, since the primary and secondary coils are formed on the plate-shaped member, the switch as a whole becomes compact, which is advantageous from the standpoint of incorporation into a device.

[Brief description of drawings]

FIG. 1 is a sectional view of a key switch showing an embodiment of the present invention, FIG. 2 is a top view of the key switch, FIG. 3 is a circuit diagram of a key switch matrix using the switch, and FIG. 3 is a circuit diagram showing a key switch matrix of FIG. 2 ... Spacer, 3, 4 ... Plate-shaped member, 5 ... Primary coil, 6 ... Secondary coil, 7 ... Microcomputer.

Claims (1)

[Claims] 1. A plurality of primary coils formed on a plate-shaped member and connected in series, and a plurality of serially-connected primary coils formed on the plate-shaped member facing each primary coil. A secondary coil, a spacer for arranging a pair of coils facing each other at a space distance, a high-frequency output section for supplying a high-frequency current to the primary coil, and a voltage induced in the secondary coil. A key switch device consisting of an input unit for detection.