JPS5913814B2 - tatsuchi board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a touch board equipped with a plurality of switch elements that perform predetermined switch operations simply by lightly touching the touch board from the outside.

Conventionally, this type of keyboard has a structure in which conductive wires are arranged in a wavy manner in the X direction on the board, and conductive wires are arranged in the Y direction at a predetermined distance from the conductive wires in the X direction, and are also provided on the board. One conductor is brought into contact with the other conductor using its elasticity using a push button, or an X conductor and a Y conductor are placed close to each other on a board, and an insulating plate with holes is provided on top of the X conductor and Y conductor. In addition, a conductive sheet is placed on the upper surface of the conductive sheet, and the X conductor and the Y conductor are brought into contact by pressing this sheet from above, or the two conductors are placed concentrically on the printed circuit board. There is a device in which a flancher biased by a conductive coil spring is provided above the flancher, and by pressing the flancher, both conductors are short-circuited via the coil spring. However, these conventional techniques have the disadvantage that the output signal processing circuit is complicated. One example is to convert the positional information of a pressed key on the keyboard into voltage changes on the X and Y lines by resistor division, and then supply this voltage to two semiconductor devices or amplifiers with different thresholds. and generates a logic output signal based on the difference between the threshold values,
There are things that can be taken out to the line and Y line, but it is necessary to prepare semiconductor elements or amplifiers for each of the X line and Y line, and these elements and amplifiers are required as many as the number of X lines and Y lines, It had the disadvantage of becoming complicated. The object of the present invention is to configure the output signal processing circuit of the conventional keyboard with a simple circuit without particularly changing the structure of the keyboard, thereby obtaining a highly reliable keyboard.

An embodiment of the invention will be described with reference to the drawings. 1st
The contact board designated by reference numeral 1 in the figure includes first conductor elements Al and A arranged parallel to each other at predetermined intervals on the same plane.
2...An group, a second conductive element group Bl, B2...Bn group extending in a direction perpendicular to these conductive elements A1 to An on a different plane, and a first and second conductive element group It is composed of an insulating substrate 2 that holds conductor elements A1 to An and B1 to Bn in predetermined positions. One side of the first conductive elements A1 to An is exposed on the surface κ of the substrate 2, and the second
Some of the conductor elements B1 to Bn are connected to the first conductor elements A1 to Bn.
It has a partially bent shape so as to be exposed on the surface of the substrate 2 near the part where it intersects with An.
Reference numeral 3 denotes an insulating sheet located on the surface of the contact board 1, in which openings 4 are formed at positions corresponding to the intersections between the first and second conductor elements A1 to An and B1 to Bn and areas in the vicinity thereof. , 5 indicates a flexible conductor sheet stacked on the insulating sheet 3, and 6 indicates a protective sheet made of a flexible insulator stacked on the conductor sheet 5. 6 is pressed, as shown in FIG.
It contacts both one of the conductor elements An and one of the second conductor elements B1 to Bn to electrically connect them. An electrical circuit of a touch board having such a configuration is shown in FIG.

Further, FIG. 3 shows an example of a detection circuit for detecting at which position a part of the protective sheet 6 is pushed. This detection circuit 5 includes first conductor elements A1 to An
a resistor Rb connected between adjacent ones of the second conductor elements B1 to Bn, a resistor Ba connected between adjacent ones of the second conductive elements B1 to Bn, and a first and second
A constant current power source 7 is connected to a conductor element (for example, between A1 and B1) 4. Further, the resistor Rs feeds back the terminal voltage to the constant current power supply 1, and connects one of the first conductive elements A1 to An and the second conductive element B.
It functions to supply a constant current to a circuit formed by connecting any one of nodes 1 to Bn.

Therefore, the detection terminals VyO located at both ends of the resistor group Ra
and Vy, and the resistance Rx between the detection terminals VxO and Vy located at both ends of the resistor Rb group are the resistances Rx between the first and second conductive elements A1 to An and B1 to Bn, which are connected to each other. It depends on the combination when pressed, that is, the position pressed. Therefore, by detecting the resistances Ry and Rx, it is possible to detect whether a part of the protective sheet 6 has been pressed and the position where it has been pressed. Resistance R
An example of a circuit for detecting y and Rx is shown in FIG.

In FIG. 4, the voltage corresponding to the resistor Rx is detected by the first differential amplifier 8, and the voltage corresponding to the resistor Ry is detected by the second differential amplifier 9, and their respective outputs are detected by the A/D converter.
After being converted into digital signals by converters 10 and 11, they are respectively taken out as outputs of the X and Y coordinates. In addition, the first and second conductor elements A1~
The change in the terminal voltage of the resistor Rs when An and B1 to Bn are connected is detected by the level detector 12, and the change in the terminal voltage of the resistor Rs when An and B1 to Bn are connected is detected by the level detector 12.
A strobe signal is obtained to read the 0 and 11 outputs. For example, in Fig. 3, the first conductor A3 and the second conductor
If the intersection with conductor B2 is pressed, then Rb, Rb
, Ra flows from the constant current power supply 7 into the series circuit.

Therefore, a voltage drop of 2Rb occurs between VxO and VXl in FIG. 4, and this becomes the input to the first differential amplifier 8.
Further, a voltage drop corresponding to Ra occurs between Vy and VyO, and this becomes an input to the second differential amplifier 9. This makes the first
The intersection of the conductor A3 and the second conductor B2 is detected. As described above, the present invention particularly provides a resistor connected between adjacent first conductive elements and a resistor connected between adjacent second conductive elements, each located at the forefront end. A constant current source connected to the first and second conductor elements, and a terminal voltage fed back to the constant current source, the first
A resistor that supplies a constant current to a circuit formed by connecting any one of the conductive elements and any one of the second conductive elements, and a resistor that supplies a constant current to a circuit formed by connecting any one of the conductive elements of A first differential amplifier connected between detection terminals located at both ends of a group of resistors connected between the first differential amplifier and an adjacent one of the second conductor elements located at both ends of the group of resistors connected between the two adjacent conductive elements. A second differential amplifier connected between the detection terminals, an A/D converter that converts the output of each differential amplifier into a digital signal, and a resistor terminal when the first and second conductive elements are connected. A level detector that detects changes in voltage and an output signal of this level detector operate the above-mentioned A/
Since it is equipped with a one-shot multipipulator that reads the output of the D converter, there is no need to provide a differential amplifier for each conductive element, and the circuit configuration is therefore extremely simple and much simpler than conventional ones. This has the advantage that the reliability of the keyboard can be improved.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of a touch board according to an embodiment of the present invention, Fig. 2 is a vertical cross-sectional view of a portion thereof, Fig. 3 is an electric circuit diagram showing an example of the usage form of the touch board, and Fig. 4 is a FIG. 3 is a block diagram showing a position detection circuit. A1-An...first conductor element, B1-Bn...second conductor element, 1...contact board, 2...substrate, 3...
·insulation. sheet, 4... opening, 5... conductor sheet,
6...Protective sheet, 7... Constant current source, Ra, Rb・
...Resistor, 8...First working amplifier, 9...Second differential amplifier, 10, 11...A/D converter, 12
...Level detector, 13...One-shot multipipulator.

Claims (1)

[Claims] 1. A first conductive element group arranged in parallel with each other at a predetermined interval, and extending in a direction intersecting the first conductive element group,
and a second conductor element group, a part of which is located near each intersection with the first conductor element, and the first conductor element group for electrically connecting the first and second conductor element groups to each other. and a flexible conductive sheet disposed above a second conductive element group, a resistor connected between adjacent first conductive elements, and a resistor connected between adjacent second conductive elements. a resistor connected therebetween, a constant current source connected to the first and second conductive elements located at the frontmost ends, and a terminal voltage fed back to the constant current source to increase the voltage of the first conductive element. A resistor that supplies a constant current to a circuit formed by connecting any one of the second conductive elements and one of the second conductive elements; A first differential amplifier connected between detection terminals located at both ends of the connected resistor group, and a detection terminal located at both ends of the resistor group connected between adjacent ones of the second conductive elements. a second differential amplifier connected between the
a D converter, a level detector that detects a change in the terminal voltage of the resistor when the first and second conductive elements are connected; A touch board equipped with a one-shot multivibrator that reads the output of the /D converter.