JPH0654459B2 - Touch panel input device - Google Patents

Description

Description: (a) Technical Field The present invention relates to an input device having a transparent sheet-like touch panel switch installed on a CRT screen or the like, and in particular, can determine a failure location when an abnormality occurs in the touch panel switch. The present invention relates to a touch panel input device.

(b) Summary of the invention, the touch panel input device according to the present invention, a means for measuring the voltage of both ends of the conductive sheet and the intermediate tap when a voltage is applied to one conductive sheet while providing the conductive sheet with the intermediate tap. Is provided, and by comparing each voltage with a normal value, it is possible to determine whether or not the touch panel switch operates normally, and where the failed part is when it does not operate normally.

(c) Conventional Technology and Its Deficiencies Description of Touch Panel Switch Used in Touch Panel Input Device First, FIG. 7 shows the configuration of the touch panel switch. The touch panel switch is composed of an upper panel 10 and a lower panel 20. The upper panel 10 will be described. The touch panel surface is formed on a transparent resin film substrate. Resistors 12a, 1 are provided on both sides of the substrate surface.
2b is formed, and conductor stripes 11 (11a to 11g) having a constant width are provided between both resistors in a ladder shape at regular intervals. Although seven conductor stripes are shown in this figure, 16 to 64 conductor stripes are formed on a CRT screen such as an ATM. The resistors 12a and 12b and the conductor stripe 11 are made of ITO (Ind
ium Tin Oxide) or the like is vapor-deposited on the base material.
Lead wires 13, 1 are provided on both ends of the resistors 12a, 12b.
4 is connected. The lead wires 13 and 14 are connected to a voltage applying circuit (not shown).

When a voltage (Vcc) is applied to the resistors 12a and 12b via the lead wires 13 and 14, a voltage gradient from one end to the other end is formed in the resistors 12a and 12b. A voltage having the same magnitude as the voltage at the connection point of the conductor stripes of the resistors 12a and 12b is generated in the conductor stripes 11a to 11g connected to the resistors 12a and 12b. The lower panel 20 is also configured similarly to the upper panel 10. 21 (21a to 21e) is a conductor stripe, 22 (22a, 22b) is a resistor, 2
Reference numerals 3 and 24 are lead wires.

A touch panel switch is constructed by disposing the upper panel 10 and the lower panel 20 so that the conductor stripe surfaces face each other so that the voltage inclination directions are orthogonal to each other at a minute interval. In this figure, the upper panel 10 is installed so that the voltage gradient is horizontal (X axis) direction and the lower panel 20 is vertical (Y axis) direction.
The voltage (Vcc) is alternately applied to the upper panel 10 and the lower panel 20.

Description of Conventional Touch Panel Input Device FIG. 6 is a block diagram of a conventional touch panel input device including the touch panel switch. Hereinafter, the lead wires 13, 14, 23 and 24 are referred to as A, B, C and D, respectively. The CPU 2 is connected to the A / D converter 3, the I / O port 4 and the memory 5 via the bus. A / D converter 3
Includes gate 8a-buffer amplifier 7a, gate 8b-buffer amplifier 7b, gate 8c-buffer amplifier 7c and gate 8d.
-Connected to A, B, C and D via buffer amplifier 7d. The lead wires 13, 14, 23, 24 are provided with switching transistors 6a, 6b, 6c, 6d, respectively.
Are connected. These switching transistors 6
a, 6b, 6c and 6d correspond to the switch circuit.

These switching transistors are CPU2-I / O
6 by the ON signals a, b and c, d from the port 4
The on / off operation is repeated alternately for combinations of a, 6b and 6c, 6d. When the switching transistors 6a and 6b are turned on, the voltage (Vcc) is applied to the upper panel 10, and when the switching transistors 6c and 6d are turned on, the voltage (Vcc) is applied to the lower panel 20. CP
When the voltage (Vcc) is applied to the upper panel 10, U2 outputs the ON signals e, f, g at the same time to output the gates 8a, 8b,
Turn on 8d. By opening the gates 8a and 8b, the voltage across the upper panel 10, that is, the voltage actually applied to the resistors 12a and 12b of the upper panel 10 is measured. Further, by opening the gate 8d, the contact detection voltage (Vx) in the X-axis direction detected by the lower panel 20 when the touch panel switch 1 is pressed is input to the A / D converter 3.

Similarly, when voltage (Vcc) is applied to the lower panel, CP
U2 outputs ON signals e, f, g to output gates 8b, 8
Turn on c and 8d. By opening the gates 8c and 8d, the voltage across the lower panel 20, that is, the lower panel 20.
The voltage actually applied to the resistors 22a and 22b is measured. Further, by opening the gate 8b, when the touch panel switch 1 is pressed, the upper panel 1
The contact detection voltage (Vy) in the Y-axis direction detected by 0 is A / D
Input to the converter 3.

When the touch panel switch 1 is pressed when the voltage (Vcc) is applied to the upper panel 10 and the upper panel 10 and the lower panel 20 are in contact with each other, the conductor stripes at the contact points (contact points) of the upper panel 10 The voltage generated at 11 is applied to the lower panel 20 via the contacts. Since the buffer amplifier 7d has an extremely high input impedance, the film surface resistance of the lower panel 20 and the upper panel 10 are reduced.
The current flowing from the lower panel 20 to the lower panel 20 can be ignored. Therefore, the voltage input to the A / D converter 3 at this time can be regarded as the voltage (Vx) itself generated at the contact point of the upper panel 10. Based on this voltage (Vx) and the voltage actually applied to the resistors 12a and 12b of the upper panel 10, the left and right directions of the contacts (X axis direction)
Position (X coordinate value) can be detected.

The voltage (Vcc) is applied to the upper panel 1 as described above.
0, alternately for the lower panel 20. Immediately after the voltage (Vcc) is applied to the upper panel 10 to detect the X coordinate value, the voltage (Vcc) is applied to the lower panel 20 and the gates 8c, 8d and the gate 8b are turned on. The voltage generated at the contact of the lower panel 20 by applying the voltage (Vcc) to the lower panel 20 is applied to the upper panel via the contact. The buffer amplifier 7b is the buffer amplifier 7
Since the input impedance is very high like d, the film surface resistance of the upper panel 10 and the current flowing from the lower panel 20 to the upper panel 10 can be ignored. Therefore, at this time, the voltage input to the A / D converter 3 can be regarded as the voltage (Vy) itself generated at the contact point of the lower panel 20. The vertical position (Y-axis direction) position (Y coordinate value) of the contact can be detected based on this voltage (Vy) and the voltage actually applied to the resistors 22a and 22b of the lower panel 20. it can. In this way, by obtaining the X and Y coordinate values, the contact point (pressed position) when the touch panel switch 1 is pressed can be detected.

The switching transistors 6a, 6b, 6
ON signal (a, b, c, d) of c, 6d and gate 8
ON signals (e, f) of b and 8d are generated by the CPU 2,
It is supplied via the I / O port 4.

The touch panel input device as described above is usually installed on a CRT screen of an automatic transaction processing device or the like, and is used as a touch key device that displays keys on the screen and determines whether the key position is pressed by the touch panel input device. That is, when the depression (contact) of the coordinate point corresponding to the image position of the displayed key is detected, it is determined that the key is depressed and the other control unit is notified.

Disadvantages of the conventional touch panel input device The voltage (Vcc) is alternately applied to the upper and lower panels of the touch panel switch 1 as described above. This voltage (Vcc) forms a voltage gradient on the touch panel. The normal formation of this voltage gradient is a necessary condition for accurately detecting the contact position. That is, when any of the switching transistors 6a to 6d is broken, or when any of the lead wires A, B, C, and D is broken, the voltage gradient is not normally formed, and the contact position detection is accurately performed. I can't do it.

Since the conventional touch panel input device does not have a function of detecting the above abnormality, the apparatus itself cannot detect the abnormality and cannot perform an action corresponding to the abnormality. For this reason, it takes time to find an abnormality in the touch panel switch, and even if it is found to be abnormal, it is necessary to re-inspect and find out which part is defective, and it is found to be abnormal. There was a drawback that it would take time to recover later.

(d) Object of the Invention In view of the above-mentioned drawbacks, an object of the present invention is to provide a touch panel input device capable of always checking the state of a touch panel switch and promptly identifying a failure location when an abnormality is found.

(e) Structure and Effect of the Invention The present invention provides electrode terminals at both ends of each of two conductive sheets facing each other, and applies a voltage between the electrode terminals at both ends of one conductive sheet to distribute the voltage on the surface. And a switch circuit that opens and closes voltage application from the voltage application circuit to the electrode terminals,
In the touch panel input device that detects a contact position from the voltage obtained by the other conductive sheet and the voltage distribution when the two conductive sheets are in contact, an intermediate tap is provided on each of the two conductive sheets, Reference voltage storage means for storing the voltage generated at the both electrode terminals and the intermediate tap when the voltage is normally applied to the conductive sheet is provided, and both electrode terminals of the one conductive sheet when the switch circuit is closed. And terminal voltage measuring means for measuring the voltage of the intermediate tap, and determining the presence or absence of a failure of the switch circuit based on the voltage of the electrode terminal measured by the terminal voltage measuring means and the electrode based on the voltage of the intermediate tap. And a failure determination unit that determines whether or not the terminal is broken.

According to the present invention configured as described above,
When a voltage is applied to the conductive sheet, the terminal voltage measuring means measures the voltages of both electrode terminals and the intermediate tap.
When all the measured voltages substantially match the stored contents of the reference voltage storage unit, it is determined that the touch panel switch is operating normally, and one of the measured voltages is stored in the reference voltage storage unit. When it does not match, it can be determined that the touch panel switch is not operating normally. When the touch panel switch is not operating normally, the failure location can be determined by determining which electrode terminal or intermediate tap voltage deviates from the stored content of the reference voltage storage means. This makes it possible to quickly detect an abnormality in the touch panel switch, and when an abnormality occurs, the failure location is determined, so repair / restoration can be performed promptly, and inconvenience to users such as customers. It can be kept to a minimum.

If such a touch panel input device is used for an automatic transaction processing device of a bank, etc., there will be no inconvenience of accepting an input in an abnormal state and processing incorrect data, which will not hinder transactions. Occurs.

(f) Embodiment FIG. 3 is a circuit diagram of a touch panel input device according to an embodiment of the present invention, and FIG. 4 is a schematic diagram of a touch panel switch used in the touch panel. The present embodiment differs from the conventional touch panel input device described with reference to FIGS. 6 and 7 in that the intermediate taps M and N are provided at the centers of the resistors of the upper panel and the lower panel, and the intermediate tap M is provided. Via the buffer amplifier 7m and gate 8m to A /
The intermediate tap N is connected to the D converter 3 and the buffer tap 7n,
This is the point connected to the A / D converter 3 via the gate 8n. In this figure, the same parts as those in the block diagram shown in FIG. It should be noted that the upper panel 10 and the lower panel 20 of the touch panel switch 1 are formed with only one resistor 12, 22 respectively, but this resistor is used as the resistor 12a in the touch panel switch shown in FIG. 12b and resistor 22a,
You may make it form two pieces like 22b. In this case, the intermediate tap may be provided on either of the two resistors. That is, the intermediate tap may be provided at any position where the intermediate potential is detected when a voltage is applied to both ends of the resistor, and the intermediate potential is set at the normal time of FIG. 2 (A). By setting it as Vm, the operation and effect of the present application can be achieved.

When the voltage (Vcc) is applied to the upper panel 10, that is, when the switching transistors 6a and 6b are turned on, the CPU 2 turns on the gates 8a and 8b as described above to turn on the voltage Va at the point A and the voltage at the point B. While measuring the voltage Vb,
At this time, the gate 8m is turned on at the same time and the voltage Vm of the intermediate tap M of the upper panel 10 is also measured. Similarly, when a voltage (Vcc) is applied to the lower panel 20, the gates 8c and 8d
Is turned on to measure the voltage Vc at the point C and the voltage Vd at the point D, and the gate 8n is turned on to measure the voltage Vn at the intermediate tap N of the lower panel 20.

Here, the ON signals a and b for turning on the switching transistors 6a and 6b are output, and the gate 8
FIG. 2 (A) shows a state judgment table of the touch panel switch when ON signals g, f, i are output to turn on a, 8b, 8m and Va, Vb, Vm are measured. When the voltage Vcc is normally applied, the voltage Va of A is Vcc, the voltage Vb of B is 0, and M is the midpoint between A and B, so the voltage Vm is
It is Vcc / 2. That is, the upper panel 10 has a normal voltage gradient of Vcc to 0V. When the switching transistor 6a fails and does not turn on, the upper panel 10
Becomes a grounded state when the switching transistor 6b is turned on, so that the voltages of Va, Vb and Vm are all zero. When the switching transistor 6b fails and does not turn on, the upper panel 10 is floated to the Vcc side due to the switching transistor 6a turning on.
The voltages of a, Vb and Vm are all Vcc. Further, when the lead wire A is disconnected, Va becomes Vcc due to the switching transistor 6a being turned on, but since the voltage is not applied to the upper panel 10, Vm and Vb remain 0. When the lead wire B is broken, the upper panel 10 floats on the Vcc side, so Va and Vm are Vcc, and Vb grounded by the switching transistor 6b is 0.

FIG. 5 is a partial configuration diagram of the memory 5. The RAM of the memory has three flags FA, FB, FM (M1, M
2, M3) is set, and ROM stores Val, Vbh, Vmh, V
ml is memorized (M4, M5, M6, M7),
The table M8 is set. The flags FA, F
B and FM are flags that are set to 1 or 2 when Va, Vb, and Vm are abnormal, and are all set to 0 when the touch panel switch is operating normally.
Val is an allowable lower limit voltage of Va (Vcc-ΔV, ΔV: allowable deviation, the same applies hereinafter), Vbh is an allowable upper limit voltage of Vb (ΔV), Vmh
Is an allowable upper limit voltage of Vm (Vcc / 2 + ΔV), and Vml is an allowable lower limit voltage of Vm (Vcc / 2−ΔV). These allowable voltages are set when the device is adjusted and stored in the ROM. The corresponding flag is set to 1 or 2 when the respective voltage is not within these tolerances. That is, Vm is Vmh
FM (M3) is set to 2 when the voltage exceeds the threshold, and the flag corresponding to the voltage is set to 1 when the other voltage is abnormal.

If the state of the touch panel switch shown in FIG. 2 (A) is expressed by the contents of the above-mentioned flags FA, FB, and FM, it becomes a table shown in FIG. 2 (B). This table is area M8
Remembered in.

These flags, allowable voltages and tables are on the upper panel 1.
Although the case of determining 0 is set, the lower panel 20 also has the same configuration as the upper panel 10, and therefore is also used when determining the voltage. In that case, Va is Vc
In addition, Vb corresponds to Vd and Vm corresponds to Vn.

FIG. 1 is a flow chart showing the operation of the CPU 2. Hereinafter, in order to apply the voltage Vcc to the upper panel 10,
The operation immediately after outputting the ON signals a and b of the switching transistors 6a and 6b will be described.

When the ON signals a and b of the switching transistors 6a and 6b are output, first, the flags FA, FB and FM are set to 0 in step n1 (hereinafter, step ni is simply referred to as ni).
, And read Va, Vb, and Vm with n2. Va at n3
If Val is equal to or lower than Val, 1 is set to the flag FA (n30). In n4, Vb and Vbh are compared, and Vb
Is greater than or equal to Vbh, the flag FB is set to 1 (n4
0). At n5 and n6, Vm is compared with Vmh and Vml, and Vm is Vm
If l or less, set flag FM to 1 (n50), Vm
Is Vmh or more, 2 is set to the flag FM (n6
0). At n7, the setting state of each flag is judged,
If all the flags are 0, the normal processing of n8 is performed. If any of the flags is not 0, the table (M8) is searched based on the setting contents of the flags to determine the failure point (n9).

If the failure is due to disconnection of the lead wire, the process proceeds to a disconnection error processing operation (n11), and if not, to the switching transistor abnormality error processing operation (n1).
2).

The above description of the operation has explained the operation when a voltage is applied to the upper panel, but when a voltage is applied to the lower panel, instead of Va, Vb, Vm, Vc, Vd,
Vn is set, and other operations are the same.

The areas M4 to M7 of the memory 5 correspond to the reference voltage storage means of the present invention, and the gates 7a, 7b, 7c, 7 are provided.
d, 7m, 7n, buffer amplifiers 8a, 8b, 8c, 8d,
8m, 8n and n2 of the above operation correspond to the terminal voltage measuring means of the present invention, and n3 and below of the above operation correspond to the failure point determining means of the present invention.

[Brief description of drawings]

FIG. 1 is a flow chart showing the operation of the control unit of the touch panel input device according to the embodiment of the present invention, and FIG. 2 (A) is the voltage of both electrode terminals and the intermediate tap when the voltage application signal is output and the failure point. Figure showing the table showing the relationship with
(B) is a diagram showing a table in which the state of (A) is represented by flags FA, FB, FM, and shows the contents of the table set in the memory of the touch panel input device. FIG. 3 is a circuit diagram of the touch panel input device, FIG. 4 is a schematic diagram of the touch panel switch, FIG. 5 is a partial configuration diagram of a memory of the touch panel input device, and FIG. 6 is a circuit diagram of a conventional touch panel input device. , FIG. 7 is a diagram showing a configuration of a conventional touch panel switch. M, N ... Middle tap, 7m, 7n ... Gate, 8m,
8n ... Buffer amplifier.

Claims (1)

[Claims] 1. A voltage application circuit for providing electrode terminals on both ends of each of two facing conductive sheets and applying a voltage between the electrode terminals on both ends of one conductive sheet to form a voltage distribution on the surface. A switch circuit for opening and closing voltage application from the voltage application circuit to the electrode terminals,
In the touch panel input device that detects a contact position from the voltage obtained by the other conductive sheet and the voltage distribution when the two conductive sheets are in contact, an intermediate tap is provided on each of the two conductive sheets, Reference voltage storage means for storing the voltage generated at the both electrode terminals and the intermediate tap when the voltage is normally applied to the conductive sheet is provided, and both electrode terminals of the one conductive sheet when the switch circuit is closed. And terminal voltage measuring means for measuring the voltage of the intermediate tap, and determining the presence or absence of a failure of the switch circuit based on the voltage of the electrode terminal measured by the terminal voltage measuring means and the electrode based on the voltage of the intermediate tap. A touch panel input device comprising: failure determination means for determining whether or not a terminal is broken.