LIQUID CRYSTAL DISPLAY DEVICE

• US 20100214261A1
• Filed: 02/02/2010
• Published: 08/26/2010
• Est. Priority Date: 02/24/2009
• Status: Active Grant

• Current Assignee: Japan Display Incorporated, Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Toshiba Mobile Display Company Limited (Japan Display Incorporated), Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Hirota, Shinichi, Arima, Kazuya, YAMANAKA, Satoru
• Granted Patent: US 9,076,402 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G09G 2310/0248 Precharge or discharge of column electrodes before or after applying exact column voltages
• CPC Class Codes: G09G 3/3655 Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors

Abstract

A liquid crystal display device includes a pixel array substrate having signal lines and scan lines arranged in a matrix, and pixel circuits arranged at intersections of the signal and scan lines. A touch panel is attached on the counter substrate to draw pictures or characters on a display panel. A first voltage generation circuit generates an analog pixel voltage applied to the signal lines and a second voltage generation circuit generates a counter electrode voltage applied to the counter electrode. A settling adjustment circuit adjusts a settling time of at least one of the analog pixel voltage and the counter electrode voltage.

Claims

1. A liquid crystal display device, comprising:

a pixel array substrate including signal lines and scan lines arranged in a matrix and pixel circuits arranged at intersections of the signal and scan lines;

a counter substrate including a counter electrode;

signal drivers connected to the signal lines to drive the signal lines;

scan drivers connected to the scan lines to drive the scan lines;

a switching transistor formed in each of the pixel circuits;

a liquid crystal layer held between a pixel electrode connected to the switching transistor and the counter electrode;

a touch panel attached on the counter substrate;

a first voltage generation circuit to generate an analog pixel voltage applied to the signal lines;

a second voltage generation circuit to generate a counter electrode voltage applied to the counter electrode; and

a settling adjustment circuit to adjust a settling time of at least one of the analog pixel voltage and the counter electrode voltage.

2. The liquid crystal display device according to claim 1, wherein the liquid crystal display device further comprises:

a precharge circuit to apply a precharge voltage to the signal lines during a horizontal blanking time prior to starting a next driving of the signal lines.

3. The liquid crystal display device according to claim 1, wherein the settling adjustment circuit comprises:

a plurality of buffer circuits with input signal delay times different from each other, and a buffer selection circuit to select one of the buffer circuits and adjust at least one of the analog pixel voltage and the counter electrode voltage.

4. The liquid crystal display device according to claim 1, wherein the signal driver circuit comprises:

an analog switch circuit to apply the analog pixel voltage to selected signal lines; and

a timing adjustment circuit to control the switching time of the analog switch so as to match to the settling time adjusted by the settling adjustment circuit.

5. The liquid crystal display device according to claim 1, wherein the liquid crystal display device further comprises:

an auxiliary capacitance line to form an auxiliary capacitance between the auxiliary capacitance line and the pixel electrode.

6. The liquid crystal display device according to claim 5, wherein the liquid crystal display device comprises:

a reference voltage generation circuit to generate a reference voltage;

a first buffer circuit to generate an auxiliary capacitance voltage applied to the auxiliary capacitance line based on the reference voltage; and

the second voltage generation circuit including a second buffer circuit to generate the counter electrode voltage based on the reference voltage.

7. A liquid crystal display device, comprising:

a pixel array substrate including signal lines and scan lines arranged in a matrix and pixel circuits arranged at intersections of the signal and scan lines;

a counter substrate including a counter electrode;

signal drivers connected to the signal lines to drive the signal lines;

scan drivers connected to the scan lines to drive the scan lines;

a switching transistor formed in each of the pixel circuits;

a liquid crystal layer held between a pixel electrode connected to the switching transistor and the counter electrode;

a touch panel attached on the counter substrate;

a precharge circuit to apply a precharge voltage to the signal lines during a horizontal blanking time prior to starting a next driving of the signal lines.

a counter electrode voltage generation circuit to generate a counter electrode voltage applied to the counter electrode;

a settling adjustment circuit to adjust a settling time of the counter electrode voltage, the settling adjustment circuit including a plurality of buffer circuits with input signal delay times different from each other, and a buffer selection circuit to select one of the buffer circuits, the settling adjustment circuit connected between the counter electrode and a voltage generation circuit.

8. The liquid crystal display device according to claim 7, wherein the touch panel includes a laminating film on a base substrate with interposed spacers between the film and the substrate, and transmissive electrodes formed on the surfaces of the film and the glass substrate, respectively.

9. A liquid crystal display device, comprising:

a pixel array substrate including signal lines and scan lines arranged in a matrix and pixel circuits arranged at intersections of the signal and scan lines;

a counter substrate including a counter electrode;

signal drivers connected to the signal lines to drive the signal lines;

scan drivers connected to the scan lines to drive the scan lines;

a switching transistor formed in each of the pixel circuits;

a liquid crystal layer held between a pixel electrode connected to the switching transistor and the counter electrode;

a touch panel attached on the counter substrate;

a precharge circuit to apply a precharge voltage to the signal lines during a horizontal blanking time prior to starting a next driving of the signal lines;

an analog pixel voltage generation circuit to generate an analog pixel voltage applied to the signal lines;

a settling adjustment circuit to adjust a settling time of the analog pixel voltage;

an analog switch circuit to apply the analog pixel voltage to selected signal lines and a timing adjustment circuit to control the switching time of the analog switch circuit so as to match the settling time adjusted by the settling adjustment circuit, and

wherein the settling adjustment circuit includes a plurality of buffer circuits with input signal delay times different from each other, and a buffer selection circuit to select one of the buffer circuits, the settling adjustment circuit connected to the analog switch circuit.

10. The liquid crystal display device according to claim 9, wherein the touch panel attached on the counter substrate includes a laminating film on a base substrate with spacers interposed between the film and the substrate, and transmissive electrodes formed on the surfaces of the film and the glass substrate, respectively.

11. A method for manufacturing a liquid crystal display device, comprising a pixel array substrate including signal lines and scan lines arranged in a matrix and pixel circuits arranged at intersections of the signal and scan lines, and a counter substrate having a counter electrode, comprising:

forming signal drivers and scan drivers connected to the signal lines and the scan lines, respectively;

forming switching transistor in each of the pixel circuits;

injecting a liquid crystal material between the pixel array substrate and the counter substrate;

attaching a touch panel on the counter substrate;

applying a first voltage to the signal lines;

applying a second voltage to the counter electrode; and

adjusting a settling time of at least one of the first voltage and the second voltage.

12. The method for manufacturing a liquid crystal display device according to claim 11, wherein the voltage values of the first and second voltages are fixed after being set.

13. A method for manufacturing a liquid crystal display device, including a pixel array substrate including signal lines and scan lines arranged in a matrix and pixel circuits arranged at intersections of the signal and scan lines, and a counter substrate including a counter electrode, the method comprising:

forming signal drivers and scan drivers connected to the signal lines and the scan lines, respectively;

forming a switching transistor in each of the pixel circuits;

injecting a liquid crystal material between the pixel array substrate and the counter substrate;

attaching a touch panel on the counter substrate;

applying a first voltage to the signal lines;

applying a second voltage to the counter electrode;

applying a precharge voltage to the signal lines during a horizontal blanking time prior to starting a next driving of the signal lines;

adjusting a settling time of the analog pixel voltage; and

applying the analog pixel voltage to selected signal lines and at a timing controlled so as to match to the adjusted settling time of the analog pixel voltage.

14. The method for manufacturing a liquid crystal display device according to claim 13, wherein the setting of the voltage level of the precharge voltage and the adjustment of the settling time by the settling adjustment circuit are fixed after being set.

15. A liquid crystal display device, comprising:

a pixel array substrate including signal lines and scan lines arranged in a matrix and pixel circuits arranged at intersections of the signal and scan lines;

a counter substrate including a counter electrode;

signal drivers connected to the signal lines to drive the signal lines;

scan drivers connected to the scan lines to drive the scan lines;

a switching transistor formed in each of the pixel circuits;

a liquid crystal layer held between a pixel electrode connected to the switching transistor and the counter electrode;

a touch panel attached on the counter substrate;

a first voltage generation circuit to generate an analog pixel voltage applied to the signal lines;

a second voltage generation circuit to generate a counter electrode voltage applied to the counter electrode;

a precharge circuit to apply a precharge voltage to the signal lines during a horizontal blanking time prior to starting a next driving of the signal lines;

settling adjustment circuits to adjust a settling time of the analog pixel voltage and the counter electrode voltage;

an analog switch circuit to apply the analog pixel voltage to selected signal lines; and

a timing adjustment circuit to control the switching time of the analog switch circuit so as to match to the settling time adjusted by the settling adjustment circuit.

16. The liquid crystal display device according to claim 15, wherein the liquid crystal display device further comprising;

an auxiliary capacitance line to form an auxiliary capacitance between the auxiliary capacitance line and the pixel electrode.

17. The liquid crystal display device according to claim 16, wherein the liquid crystal display device comprising:

a reference voltage generation circuit to generate a reference voltage;

a first buffer circuit to generate an auxiliary capacitance voltage applied to the auxiliary capacitance line based on the reference voltage; and

the second voltage generation circuit including, a second buffer circuit to generate the counter electrode voltage based on the reference voltage.

18. The liquid crystal display device according to claim 17, wherein the touch panel includes a laminating film on a base substrate with spacers interposed between the film and the substrate, and transmissive electrodes formed on the surfaces of the film and the glass substrate, respectively.