Touch-panel device

• US 20020039094A1
• Filed: 08/03/2001
• Published: 04/04/2002
• Est. Priority Date: 08/04/2000
• Status: Active Grant

• Current Assignee: Gunze Limited
• Original Assignee: Gunze Limited
• Inventors: Kobayashi, Toshiyuki, Yamada, Tsutomu
• Granted Patent: US 6,816,153 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

A touch-panel device comprises a conductive membrane, current measurement resistors which are connected their one ends to both ends of the conductive membrane and which are connected their other ends to one another, an oscillator which is connected its one end to the connection point of the current measurement resistors and is connected its other end to the ground, and a serial connection circuit of a switch and a load impedance which circuit is connected between the ground side of the oscillator and one end of the conductive membrane. The touch-panel device measures voltages V₁₀ and V₂₀ of both resistors and calculates R_k/R₀=V₂₀/(V₁₀-V₂₀) by turning the switch ON. When a touch position is to be measured, substitute R_k/R₀ to the equation of R_L/R₀=R_k(V₂-V₁)/R(V₁+V₂)+V₂/(V₁+V₂) so as to obtain a touch position. Therefore, touch position detection accuracy is improved and the cost is cheap.

Claims

1. A touch-panel device comprising;

a touch-panel including a substrate and a conductive membrane provided on the substrate;

an AC current generation section for supplying AC currents to the conductive membrane through a first point and a second point

which are at outer peripheral sections of the conductive membrane; and

current measurement sections for measuring a first current supplied through the first point and a second current supplied through the second point; and

wherein a touched position is calculated based upon the measured first current and the measured second current, and

the touch-panel device is characterized in that the device comprises an impedance which is connected by interposing a switch between one end of the AC current generation section and a connection point of the first point and one end of the current measurement section, at least, and wherein a touch position on the touch-panel is calculated based upon a current measurement value measured by the current measurement means when the switch is turned ON and another current measurement value measured by the current measurement means when the switch is turned OFF.

2. A touch-panel device as set forth in claim 1, the touch-panel device is characterized in that the switch is turned ON and turned OFF at every constant interval, a current measurement value measured by the current measurement means when the switch is turned ON is memorized, and a touch position on the touch-panel is calculated based upon the memorized current measurement value and a current measurement value measured by the current measurement means when the switch is turned OFF.

5. A touch-panel device as set forth in one of claims 1 to 4, the touch-panel device is characterized in that electrodes made of low resistance conductive material are provided at outer peripheral sections of the conductive membrane of the touch-panel.

3. A touch-panel device comprising;

a touch-panel including a substrate and a conductive membrane provided on the substrate;

an AC current generation section for supplying AC currents to the conductive membrane through a first point and a second point which are at outer peripheral sections of the conductive membrane; and

current measurement sections for measuring a first current supplied through the first point and a second current supplied through the second point; and

wherein a touched position is calculated based upon the measured first current and the measured second current, and

the touch-panel device is characterized in that a chart is provided which includes corrected touch position information each corresponding to a calculation value of the touch position, and

wherein the corrected touch position corresponding to the calculation value of the touch position is obtained from the chart.

4. A touch-panel device comprising;

a touch-panel including a substrate and a conductive membrane provided on the substrate;

an AC current generation section for supplying AC currents to the conductive membrane through a first point and a second point which are at outer peripheral sections of the conductive membrane; and

current measurement sections for measuring a first current supplied through the first point and a second current supplied through the second point; and

wherein a touched position is calculated based upon the measured first current and the measured second current, and

the touch-panel device is characterized in that a correction operation formula for correcting the calculated touch position is memorized, and wherein the calculated touch position is applied to the correction operation formula so as to perform the correction operation of the touch position on the touch-panel.

6. A touch-panel device comprising;

a touch-panel including a substrate and a conductive membrane provided on the substrate and electrodes made of low resistance conductive material lower than the resistance of the conductive membrane which electrodes are provided at peripheral sections of the conductive membrane;

an AC current generation section for supplying AC currents to the conductive membrane through a first point and a second point which are at outer peripheral sections of the conductive membrane; and

current measurement sections for measuring a first current supplied through the first point and a second current supplied through the second point, and wherein a touched position is calculated based upon the measured first current and the measured second current; and

the touch-panel device is characterized in that the resistance value of the electrodes is determined to be an optimum value using calculation formulae of

C_A=(X*R_A)/(8*ρ

)

and

C_B=(Y*R_B)/(8*ρ

).

Wherein, C_A [mm] is a maximum curvature of linearity in periphery of electrode section in X-axis direction, C_B [mm] is a maximum curvature of linearity in periphery of electrode section in Y-axis direction, R_A [Ω

] is a sum of resistances between electrodes of 1 electrodes in X-axis direction, R_B [Ω

] is a sum of resistances between electrodes of 1 electrodes in Y-axis direction, X [mm] is a length of the electrode in X-axis direction, Y [mm] is a length of the electrode in Y-axis direction, and ρ

[Ω

/□

] is a resistance value of the conductive membrane on the surface of the substrate.

7. A touch-panel device comprising;

a touch-panel including a substrate and a conductive membrane provided on the substrate and electrodes made of low resistance conductive material lower than the resistance of the conductive membrane which electrodes are provided at-peripheral sections of the conductive membrane;

an AC current generation section for supplying AC currents to the conductive membrane through a first point and a second point which are at outer peripheral sections of the conductive membrane; and

current measurement sections for measuring a first current supplied through the first point and a second current supplied through the second point; and

wherein a touched position is calculated based upon the measured first current and the measured second current, and

the touch-panel device is characterized in that the resistance values of the electrodes are sequentially changed from the first point or the second point of the electrodes to the central section of the electrode.

8. A touch-panel device as set forth in claim 7, the touch-panel device is characterized in that the resistance values of the electrodes are sequentially changed from the first point or the second point of the electrodes to the central section of the electrode by changing the thickness of the electrodes.

9. A touch-panel device as set forth in claim 7, the touch-panel device is characterized in that the resistance values of the electrodes are sequentially changed from the first point or the second point of the electrodes to the central section of the electrode by changing the width of the electrodes.

10. A touch-panel device as set forth in claim 7, the touch-panel device is characterized in that the resistance values of the electrodes are sequentially changed from the first point or the second point of the electrodes to the central section of the electrode by constructing the electrodes by connecting a plurality of electrode element.