CONTROL CIRCUIT AND DUAL TOUCH CONTROL METHOD THEREOF FOR A FOUR-WIRE RESISTIVE TOUCH PANEL

• US 20130181939A1
• Filed: 07/18/2012
• Published: 07/18/2013
• Est. Priority Date: 01/18/2012
• Status: Active Grant

• Current Assignee: National Taiwan University of Science and Technology
• Original Assignee: National Taiwan University of Science and Technology
• Inventors: LIN, HUNG-YI, FAHN, CHIN-SHYURNG
• Granted Patent: US 8,810,545 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

A control circuit is applied for a four-wire resistive touch panel including an upper conducting layer having a first signal terminal and a second signal terminal, and a lower conducting layer having a third signal terminal and a fourth signal terminal. The control circuit includes a control unit, a switching unit and a converter. By the switching unit, the first, second, third and fourth signal terminals are switched to connect with an input voltage terminal, a ground terminal and the converter according to a control signal of the control unit. When users press the touch panel, there is a touching point between the upper conducting layer and the lower conducting layer, and the input voltage terminal transmits to the converter through the touching point so plural coordinate values are generated. The gestures such as scrolling, zooming and rotating are distinguished by the touch panel according to the coordinate values.

Claims

1. A control circuit for a four-wire resistive touch panel, wherein said four-wire resistive touch panel comprises an upper conducting layer, with a first signal terminal and a second signal terminal disposed respective to the first signal terminal, and a lower conducting layer, with a third signal terminal and a fourth signal terminal disposed respective to the third signal terminal;

and the extensive direction for the first signal terminal is perpendicular to the extensive direction for the third signal terminal;

the control circuit comprising;

a control unit utilized to generate a control signal;

a circuit switching unit, electrically connected to the control unit and having an input voltage terminal and a ground terminal, for switching the input voltage terminal and the ground terminal in connection with a pair of electrode configurations selected from the group consisting of the first signal terminal, the second signal terminal, the third signal terminal and the fourth signal terminal under the command of the control signal so that two other non-selected signal terminals are left open; and

an analog-to-digit converter, electrically connected to the control unit and having a converting terminal, for switching the converting terminal in connection with one of the two other non-selected signal terminals under the command of control signal;

wherein when a user presses the touch panel, a touching point, contacting a corresponding point on the lower conducting layer, which is a depressed point of the upper conducting layer is formed, so that a input voltage from the input voltage terminal is delivered to the converting terminal via the touching point to generate a digitized coordinate value.

2. The control circuit for a four-wire resistive touch panel of claim 1, wherein when the first signal terminal is electrically connected to the input voltage terminal and the second signal terminal is electrically connected to the ground terminal of the circuit switching unit respectively, the analog-to-digit converter generates a first coordinate value as the third signal terminal is electrically connected to the converting terminal of the analog-to-digit converter, while the analog-to-digit converter generates a second coordinate value as the fourth signal terminal is electrically connected to the converting terminal of the analog-to-digit converter.

3. The control circuit for a four-wire resistive touch panel of claim 1, wherein when the third signal terminal is electrically connected to the input voltage terminal and the fourth signal terminal is electrically connected to the ground terminal of the circuit switching unit respectively, the analog-to-digit converter generates a third coordinate value as the first signal terminal is electrically connected to the converting terminal of the analog-to-digit converter, while the analog-to-digit converter generates a fourth coordinate value as the second signal terminal is electrically connected to the converting terminal of the analog-to-digit converter.

4. The control circuit for a four-wire resistive touch panel of claim 1, wherein when the third signal terminal is electrically connected to the input voltage terminal and the second signal terminal is electrically connected to the ground terminal of the circuit switching unit respectively, the analog-to-digit converter generates a fifth coordinate value as the first signal terminal is electrically connected to the converting terminal of the analog-to-digit converter, while the analog-to-digit converter generates a sixth coordinate value as the fourth signal terminal is electrically connected to the converting terminal of the analog-to-digit converter.

5. A dual touch control method for a four-wire resistive touch panel, wherein said four-wire resistive touch panel comprises an upper conducting layer with a first signal terminal disposed in parallel with X coordinate axis of the touch panel and a second signal terminal is disposed in parallel with X coordinate axis of the touch panel as well as a lower conducting layer with a third signal terminal disposed in parallel with coordinate axis of the touch panel and a fourth signal terminal disposed in parallel with Y coordinate axis of the touch panel, such that the X coordinate axis is perpendicular to Y coordinate axis;

said dual touch method comprising steps of;

providing a control unit utilized to generate a control signal;

providing a circuit switching unit having an input voltage terminal and a ground terminal to switch the input voltage terminal and the ground terminal in connection with a pair electrode configuration selected from the group consisting of the first signal terminal, the second signal terminal, the third signal terminal and the fourth signal terminal under the command of the control signal so that two other non-selected signal terminals are left in open free manner;

providing an analog-to-digit converter, electrically connected to the control unit and having a converting terminal, for switching the converting terminal thereof in connection with either one of the two non-selected signal terminals previously under the command of the control signal;

forming a touching point when a user presses the touch panel with a finger, wherein the touching point is a depressed point on the upper conducting layer contacting a corresponding point of the lower conducting layer, so that a input voltage from the input voltage terminal is delivered to the converting terminal via the touching point to generate a plurality of digitized coordinate values;

capturing the digitized coordinate values including the first coordinate value and the second coordinate value on the X coordinate axis, the third coordinate value and the fourth coordinate value on the Y coordinate axis, as well as the fifth coordinate value and the sixth coordinate value on the Z coordinate axis;

determining whether the touching point is a double-touch pattern in accordance with the third coordinate value, the fifth coordinate value and the sixth coordinate value;

if the double-touch pattern is detected and recognized, calculating a first variance for the first coordinate value and third coordinate value and calculating a second variance for the second coordinate value and the fourth coordinate value;

determining whether the result is a first categorical indication in accordance with the first variance and the second variance;

calculating a correlation coefficient between the first coordinate value and the second coordinate value;

calculating a first standard deviation with the first coordinate value and the second coordinate value, then a second standard deviation with the first coordinate value, the second coordinate value, the third coordinate value and the fourth coordinate value; and

determining whether the result is a second categorical indication or a third categorical indication in accordance with the first standard deviation, the second standard deviation and the correlation coefficient.

6. The dual touch control method for a four-wire resistive touch panel of claim 5, wherein the sequence of determining whether the result is the first categorical indication, the second categorical indication and the third categorical indication is interchangeable in suitably adaptable manner.

7. The dual touch control method for a four-wire resistive touch panel of claim 5, wherein said first categorical indication refers to a gesture of scrolling page.

8. The dual touch control method for a four-wire resistive touch panel of claim 5, wherein said second categorical indication refers to a gesture of zooming page.

9. The dual touch control method for a four-wire resistive touch panel of claim 5, wherein said third categorical indication refers to a gesture of rotating page.