Device for controlling touch panel

• US 7,479,951 B2
• Filed: 02/17/2005
• Issued: 01/20/2009
• Est. Priority Date: 07/22/2004
• Status: Expired due to Fees

• Current Assignee: Digitech Systems Incorporated
• Original Assignee: Digitech Systems Incorporated
• Inventors: Kim, Chang Hwan
• Primary Examiner(s): Lefkowitz; Sumati
• Assistant Examiner(s): Beck; Alexander S
• Application Number:
  US11/067,831
• Publication Number:
  US 20060017704A1
• Time in Patent Office: 1,433 Days
• Field of Search: 178 1801- 1803, 178/18.05, 178/19.01, 178 1906- 2004, 327/517, 345/156, 345/173, 345/174, 345/179, 379/93.19
• US Class Current: 345/179
• CPC Class Codes: G06F 3/0436 in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate

Abstract

Disclosed herein is a device including a differential amplification unit for supplying current to the touch panel; a signal amplification unit for amplifying the output voltage of the differential amplification unit; an analog-digital conversion unit for converting the analog output signal of the signal amplification unit into a digital signal; a control unit for measuring the signal output from the analog-digital conversion unit and detecting the position of an object when the object touches the touch panel; and a sine wave generating unit for providing a sine wave signal to the differential amplification unit in response to the output signal of the control unit, supplying a maximum current to the differential amplification unit while the touch panel is in a standby state, and controlling the level of the sine wave signal in response to conductivity of the object when the object touches the touch panel.

Claims

1. A device for controlling a touch panel comprising:

a differential amplification unit for supplying current to a touch panel;

a signal amplification unit for amplifying the output voltage of the differential amplification unit;

an analog-digital conversion unit for converting the analog output signal of the signal amplification unit into a digital signal;

a control unit for measuring the signal output from the analog-digital conversion unit and detecting the position of an object when the object touches the touch panel; and

a sine wave generating unit for providing a sine wave signal to the differential amplification unit in response to an output signal of the control unit, supplying a maximum current to the differential amplification unit while the touch panel is in a standby state, and controlling the level of the sine wave signal in response to conductivity of the object when the object touches the touch panel.

2. The device as claimed in claim 1, further comprising a filtering unit for removing a noise included in the output signal of the signal amplification unit and transmitting the signal to the analog-digital conversion unit.

3. The device as claimed in claim 1, wherein, when the object touches the touch panel, the sine wave generating unit reduces the level of the sine wave signal provided to the differential amplification unit when the quantity of current supplied from the differential amplification unit to the touch panel is large but increases the level of the sine wave signal when the quantity of current is small.

4. The device as claimed in claim 1, wherein the sine wave generating unit comprises:

a square wave controller for receiving a square wave signal from the control unit and controlling the level of the square wave signal;

a triangle wave converter for converting the square wave signal output from the square wave controller into a triangle wave signal; and

a sine wave generator for converting the triangle wave signal output from the triangle wave converter into a sine wave signal and supplying the sine wave signal to the differential amplification unit.

5. The device as claimed in claim 4, wherein the square wave controller includes a potentiometer for controlling the level of the square wave signal in response to a control signal output from the control unit and transmitting the square wave signal to the triangle wave converter.