Liquid crystal display device

• US 10,394,367 B2
• Filed: 05/23/2016
• Issued: 08/27/2019
• Est. Priority Date: 06/08/2012
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: Matsumoto, Shuuichirou, Aoki, Yoshinori
• Primary Examiner(s): Chang, Kent W
• Assistant Examiner(s): Au, Scott
• Application Number:
  US15/162,050
• Publication Number:
  US 20160266714A1
• Time in Patent Office: Days
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/134336 Matrix
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• 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 3/0443 using a single layer of sensing electrodes
• 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: G09G 3/3696 Generation of voltages supplied to electrode drivers

Abstract

In a liquid crystal display device with a touch panel function, a second substrate has detection electrodes of a touch panel, each pixel has a pixel electrode and a counter electrode, the counter electrode is divided into a plurality of blocks, and the counter electrodes of the respective divided blocks are shared to the respective pixels of a plurality of display lines side by side, the counter electrodes of the respective divided blocks is also used as scanning electrodes of the touch panel, and a driver circuit is provided to apply a counter voltage and a touch panel scanning voltage to the counter electrodes of the respective divided blocks, and the driver circuit can adjust a supply start timing of the touch panel scanning voltage to be applied to the counter electrodes of the respective divided blocks.

Claims

1. A liquid crystal display device including a liquid crystal display panel, the liquid crystal display panel comprising:

a plurality of pixel electrodes arranged in a matrix;

a plurality of video signal lines, each being supplied with a video signal in a video signal applying cycle;

a counter electrode divided into a plurality of blocks;

a counter electrode selector circuit supplying a counter voltage and a touch panel scanning voltage to the counter electrode of the respective divided blocks;

a counter voltage supplying line connected to the counter electrode selector circuit and supplying the counter voltage; and

a touch panel scanning voltage supplying line connected to the counter electrode selector circuit and supplying the touch panel scanning voltage,

wherein

the counter electrode selector circuit includes a selector circuit which connects the touch panel scanning voltage supplying line and the counter electrode in a touch detection period, and the counter voltage supplying line and the counter electrode in a pixel write period,

the touch panel scanning voltage is applied to one block of the counter electrode a plurality of times in the touch detection period,

a length of the touch detection period includes the video signal applying cycle and is longer than the video signal applying cycle, and

an output of the touch panel scanning voltage is synchronized with the video signal applying cycle in the touch detection period.

2. The liquid crystal display device according to claim 1, wherein

the selector circuit includes a first switch and a second switch,

the first switch is on state in the touch detection period and connects between the touch panel scanning voltage supplying line and the counter electrode, and

the second switch is on state in the pixel write period and connects between the counter voltage supplying line and the counter electrode in the pixel write period.

3. The liquid crystal display device according to claim 2, wherein

the counter electrode selector circuit includes an address decoder circuit, and

the address decoder circuit outputs a select signal which turns on the first switch in the touch detection period.

4. The liquid crystal display device according to claim 3, wherein

the liquid crystal display panel includes a plurality of address signal lines which connect to the address decoder circuit, and

the address decoder circuit outputs the select signal which is decoded by a combination of signals of the plurality of address signal lines.

5. The liquid crystal display device according to claim 4, wherein number of the plurality of address signal lines is less than that of the divided blocks.

6. The liquid crystal display device according to claim 4, wherein the address decoder circuit receives a signal of the plurality of address signal line or an inverted signal of the plurality of address signal line.

7. A liquid crystal display device comprising:

a liquid crystal display panel including a substrate;

a plurality of pixel electrodes formed on the substrate and arranged in a matrix;

a plurality of video signal lines, each being supplied with a video signal in a video signal applying cycle;

a counter electrode divided into a plurality of blocks and opposed to the plurality of pixel electrodes commonly;

a counter electrode selector circuit supplying a counter voltage and a touch panel scanning voltage to the counter electrode of the respective divided blocks and formed on the substrate;

a counter voltage supplying line connected to the counter electrode selector circuit and supplying the counter voltage; and

a touch panel scanning voltage supplying line connected to the counter electrode selector circuit and supplying the touch panel scanning voltage,

wherein

the counter electrode selector circuit includes a selector circuit which connects the touch panel scanning voltage supplying line and the counter electrode in a touch detection period, and the counter voltage supplying line and the counter electrode in a pixel write period,

the touch panel scanning voltage is applied to one block of the counter electrode a plurality of times in the touch detection period,

the touch detection period includes plural consecutive video signal applying cycles, and

an output of the touch panel scanning voltage is synchronized with the video signal applying cycle of the touch detection period.

8. The liquid crystal display device according to claim 7, wherein

the selector circuit includes a first switch and a second switch,

the first switch is on state in the touch detection period and connects between the touch panel scanning voltage supplying line and the counter electrode, and

the second switch is on state in the pixel write period and connects between the counter voltage supplying line and the counter electrode in the pixel write period.

9. The liquid crystal display device according to claim 8, wherein

the counter electrode selector circuit includes an address decoder circuit, and

the address decoder circuit outputs a select signal which turns on the first switch in the touch detection period.

10. The liquid crystal display device according to claim 9, wherein

the liquid crystal display panel includes a plurality of address signal lines which connect to the address decoder circuit, and

the address decoder circuit outputs the select signal which is decoded by a combination of signals of the plurality of address signal lines.

11. The liquid crystal display device according to claim 10, wherein number of the plurality of address signal lines is less than that of the divided blocks.

12. The liquid crystal display device according to claim 10, wherein the address decoder circuit receives a signal of the plurality of address signal line or an inverted signal of the plurality of address signal line.