JPH0854977A - Resistive touch panel - Google Patents

Abstract

(57) [Summary] [Purpose] An object is to provide a resistive film type touch panel that can detect that two or more points are simultaneously input due to an incorrect input such as a touch, and prevent the incorrect input. [Structure] Resistance film sheet 50 of resistance film type touch panel
Voltage is detected from the two electrodes of the
An interrupt generation circuit 56 is provided for measuring the output voltage and generating an interrupt by the output. Therefore, it is possible to detect that two or more points are input at the same time, and prevent erroneous recognition due to a touch or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistive film type touch panel provided in a portable information terminal device or the like.

[0002]

2. Description of the Related Art A resistive touch panel is widely used as an input device for portable information terminals and the like. The conventional resistive touch panel will be described below.

FIG. 4 is a schematic block diagram of a control circuit of a conventional resistive film type touch panel. 1 is a CPU, 2 is an address bus, 3 is a data bus, 4 is a touch panel control circuit, 5 is a resistive film type touch panel, and 6 is an analog / digital converter. Touch panel control circuit 4 of this conventional example
Is for switching the measurement of the input position in the x-axis direction or the y-axis direction.

FIG. 5 is a block diagram of an input position detection circuit of a conventional resistive film type touch panel. 7 is a DC power source, 8 is a grounding part, 9 to 12 are electrodes, 13 and 14 are resistance film sheets, 1
Reference numeral 5 is an input pen, 16a and 16b are input points, 17 is a contact resistance, and 18 is a voltage detection terminal. The two resistive film sheets 13 and 14 are laminated with a dot spacer (not shown) interposed therebetween.

FIG. 6 is an equivalent circuit diagram of an input position detection circuit of the conventional resistive film type touch panel shown in FIG. 19 is a DC power supply, 20 and 21 are resistive film sheets, 22 is an input point,
Reference numeral 23 is a contact resistance, and 24 is a voltage detection terminal.

The operation of the resistive film type touch panel constructed as described above will be described below. First,
The input position detection circuit of FIG. 5 will be described. For convenience, the x and y directions are determined as shown in the lower left of the figure. Resistive film sheet 1
3, 14 are separated by dot spacers unless input is made. Resistive film sheet 1 for x-axis measurement
A DC power source is loaded on one electrode 9 of the third electrode 3, and the electrode 10 on the opposite side of the same resistive film sheet 13 as the electrode 9 is grounded. The electrode 12 of the other resistive film sheet 14 is used as a voltage detection terminal, and its output is connected to the analog / digital converter 6. The electrode 11 is open.

In the above state, it is assumed that the pen 15 is used to input to the input point 16a. Then, the resistance film sheets 13 and 14 are separated by the dot spacers, but when input with a sufficient force by the pen 15, the input point 16 is input via the contact resistance 17.
a and the input point 16b contact. Therefore, the potential of the input point 16a can be detected from the voltage detection terminal 18.
Therefore, this voltage value can be converted into a digital value by the analog / digital converter 6 and detected as position information data. Since the y-axis direction measurement is the same, the description thereof will be omitted.

[0008]

However, in the above-mentioned conventional configuration, since the input points 16a and 16b are detected by the partial pressure of the contact points between the two resistive film sheets 13 and 14, two or more points are simultaneously detected due to a touch or the like. When input, the voltage value applied to the combined resistance at the input point is detected, which causes a problem of incorrect input.

An object of the present invention is to solve the above-mentioned conventional problems, and an object thereof is to provide a resistive film type touch panel having a mechanism which is prevented from being erroneously input due to a touch or the like.

[0010]

In order to achieve this object, the resistance film type touch panel of the present invention compares two electrodes for detecting a voltage value at an input point with a voltage output from the two electrodes. As a result, a voltage comparison means for detecting an erroneous input is constructed.

[0011]

With this configuration, when two or more points are simultaneously input to the resistive film type touch panel due to a touch or the like, a difference occurs in the voltage values output across the resistive film sheet on the voltage detection side. Therefore, by detecting this difference by the voltage comparison means, it is possible to prevent an erroneous input due to a touch or the like.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will now be described with reference to the drawings. 1 is a schematic block diagram of a control circuit of a resistive touch panel according to an embodiment of the present invention, FIG. 2 is a configuration diagram of an input position detection circuit of the resistive touch panel, and FIG. 3 is an input position of the resistive touch panel. It is an equivalent circuit diagram of a detection circuit. In FIG. 1, 25 is a CPU, 26 is an address bus, 27 is a data bus, 28 is a touch panel control circuit, 29 is a resistive touch panel, and 30 is analog /
A digital converter, 31 is a voltage comparison circuit, and 32 is an interrupt generation circuit.

In FIG. 2, 33 is a DC power source, 34 is a grounding portion, 35 to 38 are electrodes, 39 and 40 are resistance film sheets,
41 is an input pen, 42a and 42b are input points, 43 is a contact resistance, 44 is a voltage comparison circuit, 45 is an interrupt generation circuit, 46a and 46b are erroneous input points, and 47 is a contact resistance. Further, in FIG. 3, 48 is a DC power source, 49 and 50 are resistive film sheets, 51a and 51b are input points, and 52a and 52.
Reference numeral b is an erroneous input point, 53 and 54 are contact resistances, 55 is a voltage comparison circuit, and 56 is an interrupt generation circuit. Note that the interrupt generation circuit causes an interrupt to the arithmetic unit when two or more points are simultaneously input to the resistive film type touch panel due to care, etc., and the interrupt causes the arithmetic unit to ignore the input from the touch panel, This is processed as an input error, and by doing so, erroneous input due to care can be avoided.

The operation of the resistive film type touch panel constructed as described above will be described below. In FIG.
It is assumed that the input is made at the input point 42a with the pen 41. The resistive film sheets 39 and 40 are separated by dot spacers, but when input with a sufficient force with the pen 41, the contact resistance 43
The input point 42a and the input point 42b contact each other via. Therefore, the voltage value of the input point 42a is output from the electrodes 37 and 38, but in this case, since only one point is input, the voltage values of the electrodes 37 and 38 are equal. However, when the point 46 a is erroneously input due to a touch or the like, the point 46 a and the point 46 b come into contact with each other via the contact resistance 47.

In FIG. 3, a point 51a is used as an input point and is in contact with a point 51b via a contact resistance 53, and an erroneous input point 52a is in contact with a point 52b via a contact resistance 54. Therefore, a difference occurs between the potentials V1 and V2 in FIG.
This is because the resistance film sheet 50 between the points 51b and 52b causes a voltage drop. The voltage difference is sensed by a voltage comparison means such as the voltage comparison circuit 55 and input to the interrupt generation circuit 56.

[0016]

As described above, according to the present invention, by providing the voltage comparison means, it is possible to realize an excellent resistive film type touch panel for a portable information terminal or the like which can prevent an erroneous input due to a touch or the like.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a control circuit of a resistive film type touch panel according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of an input position detection circuit of a resistive film type touch panel according to an embodiment of the present invention.

FIG. 3 is an equivalent circuit diagram of an input position detection circuit of a resistive film type touch panel according to an embodiment of the present invention.

FIG. 4 is a schematic block diagram of a control circuit of a conventional resistive touch panel.

FIG. 5 is a configuration diagram of an input position detection circuit of a conventional resistive film type touch panel.

FIG. 6 is an equivalent circuit diagram of an input position detection circuit of a conventional resistive film type touch panel.

[Explanation of symbols]

 28 Touch panel control circuit 29 Resistive film type touch panel 30 Analog / digital converter 31, 44, 55 Voltage comparison circuit 32, 45, 56 Interrupt generation circuit 35, 36, 37, 38 Electrode 39, 40, 49, 50 Resistive film sheet

Claims (1)

[Claims] 1. A resistive film sheet, two dot spacers separating the resistive film sheets, an electrode for applying a voltage when detecting an input position, an electrode for grounding, and a voltage value at an input point. A resistive film type touch panel comprising two electrodes for detection and a voltage comparison means for detecting an erroneous input by comparing a voltage output from the two electrodes.