Liquid crystal display and method thereof

• US 8,054,261 B2
• Filed: 09/28/2006
• Issued: 11/08/2011
• Est. Priority Date: 10/26/2005
• Status: Expired due to Fees

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Joo Hyung, Lee, Myung Woo, Pak, Sang Jin
• Primary Examiner(s): Hjerpe; Richard
• Assistant Examiner(s): Shapiro; Leonid
• Application Number:
  US11/536,017
• Publication Number:
  US 20070091013A1
• Time in Patent Office: 1,867 Days
• Field of Search: 345/87, 345/173, 345/104
• US Class Current: 345/87
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells
• CPC Class Codes: G06F 3/047 using sets of wires, e.g. crossed wires
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A liquid crystal display includes a first panel, a second panel facing and separated from the first panel, a liquid crystal layer interposed between the first and second panels, a plurality of sensor data lines formed on the second panel, a plurality of variable capacitors of which capacitance thereof is varied by pressure, the variable capacitors connected to the sensor data lines, a plurality of reference capacitors connected to the sensor data lines, and first reset transistors and second reset transistors connected to the sensor data lines and supplying a first reset voltage and a second reset voltage to the sensor data lines at different times, respectively.

Claims

1. A liquid crystal display comprising:

a first panel;

a second panel facing and separated from the first panel;

a liquid crystal layer interposed between the first and second panels;

a plurality of sensor data lines formed on the second panel;

a plurality of variable capacitors of which capacitance thereof is varied by pressure, the variable capacitors connected to the sensor data lines;

a plurality of reference capacitors connected to the sensor data lines;

first reset transistors and second reset transistors connected to the sensor data lines and supplying a first reset voltage and a second reset voltage to the sensor data lines at different times, respectively;

a plurality of output transistors connected to the sensor data lines and generating output signals based on sensor data signals flowing through the sensor data lines; and

a sensing signal processor supplied with the output signals from the output transistors and generating sensing signals based on the output signals,

wherein the variable capacitors comprise first capacitance electrodes formed on the first panel and second capacitance electrodes formed on the second panel, and the sensor data lines function as the second capacitance electrodes; and

wherein the first reset transistors apply the first reset voltage to the sensor data lines before the sensing signal processor generates the sensing signals.

2. The liquid crystal display of claim 1, wherein the output transistors are disposed on a periphery area of the second panel.

3. The liquid crystal display of claim 1, wherein the sensing signal processor further comprises integrators integrating the output signals to generate the sensing signals.

4. The liquid crystal display of claim 3, wherein the integrators comprise amplifiers and capacitors.

5. The liquid crystal display of claim 1, further comprising current sources connected to the output transistors and the sensing signal processor, the current sources each flowing a constant current.

6. The liquid crystal display of claim 5, wherein the current sources comprise thin film transistors flowing the constant current while the sensing signal processor generates the sensing signals.

7. The liquid crystal display of claim 1, wherein the first reset transistors and the second reset transistors are formed on a periphery area of the second panel.

8. The liquid crystal display of claim 1, wherein a distance between the first capacitance electrode and the second capacitance electrode for each variable capacitor is varied by pressure and the capacitance of each variable capacitor is varied based on a distance variation.

9. The liquid crystal display of claim 1, wherein the reference capacitors are supplied with a reference voltage.

10. The liquid crystal display of claim 1, wherein the first capacitance electrodes are supplied with a common voltage swinging between a first level and a second level.

11. The liquid crystal display of claim 10, wherein the sensing signal processor generates the sensing signals in a porch period between frames.

12. The liquid crystal display of claim 10, wherein the sensing signal processor generates the sensing signals within a predetermined time after the first reset transistors are turned off.

13. The liquid crystal display of claim 12, wherein the common voltage maintains one of the first level and the second level for the predetermined time.

14. The liquid crystal display of claim 13, wherein the predetermined time is at least about 1 H.

15. The liquid crystal display of claim 1, wherein the sensor data lines comprise a plurality of first and second sensor data lines extending in directions different from each other, respectively.

16. The liquid crystal display of claim 1, wherein the second reset transistors apply the second reset voltage to the sensor data lines after the sensing signal processor generates the sensing signals.