Liquid crystal display device having touch screen function and method of fabricating the same

• US 7,280,167 B2
• Filed: 06/11/2004
• Issued: 10/09/2007
• Est. Priority Date: 11/04/2003
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choi, Joon-hoo, Joo, In-soo
• Primary Examiner(s): Nelms; David
• Assistant Examiner(s): Vu; Phu
• Application Number:
  US10/865,996
• Publication Number:
  US 20050094038A1
• Time in Patent Office: 1,215 Days
• Field of Search: 349/12, 349/48, 345173-182, 345/104
• US Class Current: 349/12
• CPC Class Codes: G02F 1/133371 Cells with varying thickness of the liquid crystal layer
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/13624 having more than one switching element per pixel
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

The present invention relates to an LCD device having a touch screen function. The LCD device of the present invention includes a plurality of gate lines, a plurality of data lines intersecting the gate lines, and a plurality of signal lines that are insulated from and juxtaposed with the data lines. First to third switching elements are formed in each of a plurality of pixel regions in the form of a matrix, which are surrounded by the gate lines and the data lines. Here, a gate electrode of the first switching element is connected to a gate line Gn, a source electrode thereof is connected to the data line, and a drain electrode thereof is connected to a pixel electrode. Further, liquid crystal capacitance and storage capacitance are formed between the pixel electrode and a common electrode. At this time, the liquid crystal capacitance is changed due to variation in the liquid crystal cell gap. The second and third switching elements are designed to read variation in the liquid crystal capacitance. A source electrode of the second switching element is connected to the pixel electrode, a drain electrode thereof is connected to the signal line, and a gate electrode thereof is connected to a previous gate line Gn-1. Furthermore, a source electrode of the third switching element is connected to the data line, a drain electrode thereof is connected to the pixel electrode, and a gate electrode thereof is connected to a second previous gate line Gn-2. Each signal line is connected to each signal amplifier.

Claims

1. An LCD device having a touch screen function, comprising:

a plurality of gate lines that transfer scan signals;

a plurality of data lines that intersect the gate lines;

a detecting switching element that is formed in each of a plurality of pixel regions defined by the gate lines and the data lines, providing detecting signals that detect any change in cell gap in each of the pixel regions; and

a plurality of detecting signal lines that transfer the detecting signals from the detecting switching elements.

2. The LCD device as claimed in claim 1, further comprising a first switching element that is connected to the gate line and the data line and is turned on to charge a pixel electrode with a data voltage from the relevant data line when a gate-on signal is supplied to the relevant gate line.

3. The LCD device as claimed in claim 1, wherein the detecting switching element comprises a second switching element that is turned on to charge a pixel electrode with a previous data voltage when a gate-on signal is applied to a previous gate line, and a third switching element which is turned on to apply the previous data voltage to the detecting signal line when a gate-on signal is applied to a second previous gate line.

4. The LCD device as claimed in claim 3, further comprising a detecting signal amplifier that is connected to the detecting signal line, compares the previous data voltage with a reference voltage, and amplifies a difference between the previous data voltage and the reference voltage.

5. The LCD device as claimed in claim 1, wherein the detecting switching element comprises a second switching element that is turned on to apply a data voltage charged in a previous frame time to the detecting signal line when a gate-on signal is applied to a previous gate line.

6. The LCD device as claimed in claim 5, further comprising a detecting signal amplifier that is connected to the detecting signal line, compares the data voltage charged in the previous frame time with a reference voltage, and amplifies a difference between the data voltage charged in a previous frame time and the reference voltage.

7. The LCD device as claimed in claim 1, further comprising a detecting signal amplifier that is connected to the detecting signal line, compares the detecting signal with a reference signal, and amplifies a difference between the detecting signal and the reference signal.

8. The LCD device as claimed in claim 1, wherein the detecting signal lines are formed substantially in parallel with the data lines.

9. An LCD device having a touch screen function, comprising:

a plurality of gate lines that transfer scan signals;

a plurality of data lines that intersect the gate lines;

detecting switching elements that provide detecting signals that detect any change in cell gap in each of a plurality of pixel regions defined by the gate lines and the data lines; and

a plurality of detecting signal lines that transfer the detecting signals from the detecting switching elements.

10. The LCD device as claimed in claim 9, further comprising a detecting signal amplifier that is connected to the detecting signal line, compares the detecting signal with a reference signal, and amplifies a difference between the detecting signal and the reference signal.

11. The LCD device as claimed in claim 10, further comprising a first switching element that is connected to the gate line and the data line and is turned on to charge a pixel electrode with a data voltage from the relevant data line when a gate-on signal is supplied to the relevant gate line.