Liquid crystal display device

• US 9,535,278 B2
• Filed: 12/03/2013
• Issued: 01/03/2017
• Est. Priority Date: 12/06/2012
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: Tokita, Masahiro, Takahata, Masashi
• Primary Examiner(s): LAMB, CHRISTOPHER RAY
• Application Number:
  US14/094,991
• Publication Number:
  US 20140160371A1
• Time in Patent Office: 1,127 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G02F 1/1309 Repairing; Testing
• CPC Class Codes: G02F 1/133302 Rigid substrates, e.g. inorganic substrates
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/134318 having a patterned common electrode
• CPC Class Codes: G02F 1/136254 Checking; Testing
• 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: G02F 2202/28 Adhesive materials or arrangements
• CPC Class Codes: G06F 2203/04102 Flexible digitiser, i.e. constructional details for allowing the whole digitising part of a device to be flexed or rolled like a sheet of paper
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• 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 2354/00 Aspects of interface with display user
• 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 with a plurality of pixels arranged in a matrix includes a first substrate, a second substrate, a liquid crystal interposed between the first and the second substrates, and a detection circuit. The second substrate includes a detection electrode for a touch panel. The respective pixels have pixel electrodes and counter electrodes. The counter electrode divided into a plurality of blocks is provided common to the respective pixels on a plurality of consecutive display lines. The counter electrode divided into blocks serves as the scanning electrode for the touch panel. The detection circuit includes a calibration capacity element provided for each of the detection electrodes, having one end connected to the detection electrode, and supplies a calibration voltage to the other end of the calibration capacity element in a touched position detection process.

Claims

1. A liquid crystal display device having a plurality of pixels arranged in a matrix, comprising:

a first substrate;

a second substrate;

a liquid crystal interposed between the first and the second substrates; and

a detection circuit,

wherein the second substrate has a detection electrode for a touch panel;

each of the pixels includes a pixel electrode and a counter electrode;

the counter electrode is applied with a counter voltage for displaying and a touch scanning voltage for detecting a touch coordinate;

the counter electrode is divided into a plurality of blocks;

the counter electrode divided into blocks is provided common to the respective pixels on a plurality of consecutive display lines;

the counter electrode divided into blocks serves as a scanning electrode for the touch panel,

the detection circuit includes a calibration capacity element provided for each detection electrode, having one end connected to the detection electrode, and supplies a calibration voltage to the other end of the calibration capacity element in a touched position detection process for each intersection between the respective detection electrodes and the scanning electrodes,

the detection circuit supplies a reference voltage to both ends of the calibration capacity element, and

a voltage of the detection electrode is varied by the calibration voltage supplied to the other end of the calibration capacity element in the touched position detection process.

2. The liquid crystal display device having a plurality of pixels arranged in a matrix according to claim 1,

wherein the detection circuit includes a memory element which stores calibration digital data for each intersection between the respective detection electrodes and the counter electrode divided into blocks, and

in the touched position detection process, a calibration data voltage corresponding to the calibration digital data stored in the memory element is generated, and is supplied to the other end of the corresponding calibration capacity element.

3. The liquid crystal display device having a plurality of pixels arranged in a matrix according to claim 1, wherein the first substrate includes the pixel electrode and the counter electrode.

4. The liquid crystal display device having a plurality of pixels arranged in a matrix according to claim 1, wherein the detection circuit includes an integration circuit and a sample-hold circuit.

5. The liquid crystal display device having a plurality of pixels arranged in a matrix according to claim 4, wherein the detection circuit includes an A/D converter and a memory element which stores output digital data from the A/D converter.

6. A liquid crystal display device having a plurality of pixels arranged in a matrix, comprising:

a first substrate;

a second substrate;

a liquid crystal interposed between the first and the second substrates; and

a detection circuit,

wherein the second substrate has a detection electrode for a touch panel;

each of the pixels includes a pixel electrode and a counter electrode;

the counter electrode is applied with a counter voltage for displaying and a touch scanning voltage for detecting a touch coordinate;

the counter electrode is divided into a plurality of blocks;

the counter electrode divided into blocks is provided common to the respective pixels on a plurality of consecutive display lines;

the counter electrode divided into blocks serves as a scanning electrode for the touch panel,

the detection circuit includes a calibration capacity element provided for each detection electrodes, having one end connected to the detection electrode, and in testing a short-circuit between two adjacent detection electrodes, supplies a first calibration voltage that extracts no charge to the other end of the calibration capacity element having the one end connected to odd-numbered detection electrodes, and supplies a second calibration voltage that is allowed to sufficiently extract the charge to the other end of the calibration capacity element having the one end connected to even-numbered detection electrodes for carrying out a touched position detection process, and

a voltage of the detection electrode is varied by the first calibration voltage or the second calibration voltage supplied to the other end of the calibration capacity element in testing a short-circuit,

wherein the touch scanning voltage is not supplied to the counter electrode and the detection electrode in testing the short-circuit.

7. The liquid crystal display device having a plurality of pixels arranged in a matrix according to claim 6, wherein:

the detection circuit includes a memory element which stores calibration data for each intersection between the respective detection electrodes and the counter electrode divided into blocks;

in testing the short-circuit between the two adjacent detection electrodes, first calibration data are stored as the calibration data for each intersection between the odd-numbered detection electrode and the counter electrode divided into blocks, and second calibration data are stored as the calibration data for each intersection between the even-numbered detection electrode and the counter electrode divided into blocks, and

in testing the short-circuit between the two adjacent detection electrodes, the first calibration data voltage corresponding to the first calibration data stored in the memory element is generated, and supplied to the other end of the calibration capacity element having the one end connected to the odd-numbered detection electrode, and the second calibration data voltage corresponding to the second calibration data stored in the memory element is generated, and supplied to the other end of the calibration capacity element having the one end connected to the even-numbered detection electrode for carrying out the touched position detection process.

8. The liquid crystal display device having a plurality of pixels arranged in a matrix according to claim 6, wherein the detection circuit includes a DA converter which converts the data stored in a memory element into a calibration data voltage.

9. The liquid crystal display device having a plurality of pixels arranged in a matrix according to claim 6, wherein the detection circuit includes an integration circuit and a sample-hold circuit.

10. The liquid crystal display device having a plurality of pixels arranged in a matrix according to claim 9, wherein the detection circuit includes an A/D converter and a memory element which stores output data from the A/D converter.

11. A liquid crystal display device having a plurality of pixels arranged in a matrix, comprising a liquid crystal display panel provided with a first substrate, a second substrate, a liquid crystal interposed between the first and the second substrates, and a detection circuit,

wherein the second substrate has a detection electrode for a touch panel;

each of the pixels includes a pixel electrode and a counter electrode;

the counter electrode is divided into a plurality of blocks;

the counter electrode divided into blocks is provided common to the respective pixels on a plurality of consecutive display lines;

the counter electrode divided into blocks serves as a scanning electrode for the touch panel,

the detection circuit includes a plurality of integration circuits provided for the respective detection electrodes, and connected to the detection electrodes, a calibration capacity element provided for the detection electrode, having one end connected to the detection electrode, and a memory element which stores calibration data for each intersection between the detection electrode and the counter electrode divided into blocks;

in testing a short-circuit between two adjacent detection electrodes, first calibration data that extract no charge are stored as the calibration data for each of the intersections between odd-numbered detection electrodes and the counter electrode divided into blocks, and second calibration data that are allowed to sufficiently extract the charge are stored as the calibration data for each of the intersections between even-numbered detection electrodes and the counter electrode divided into blocks, and

in testing the short-circuit between the two adjacent detection electrodes, a reference voltage of VREF is generated and supplied to the other end of the calibration capacity element having the one end connected to the odd-numbered detection electrode as a calibration data voltage corresponding to the first calibration data stored in the memory element, and a voltage of GND to be fed to the integration circuit is generated and supplied to the other end of the calibration capacity element having the one end connected to the even-numbered detection electrode as the calibration data voltage corresponding to the second calibration data stored in the memory element for carrying out a touched position detection process.

12. The liquid crystal display device having a plurality of pixels arranged in a matrix according to claim 11,

wherein the detection circuit includes a first switch circuit connected between the detection electrode and the integration circuit, a second switch circuit which supplies the reference voltage of VREF to the detection electrode, and a third switch circuit which supplies the calibration data voltage or the reference voltage of VREF to the other end of the calibration capacity element;

the first switch circuit is turned OFF and the second switch circuit is turned ON before supplying a touch panel scanning voltage to the counter electrode divided into blocks so as to allow the third switch circuit to supply the reference voltage of VREF to the other end of the calibration capacity element, and

the first switch circuit is turned ON and the second switch circuit is turned OFF in supplying the touch panel scanning voltage to the counter electrode divided into blocks to allow the third switch circuit to supply the calibration data voltage to the other end of the calibration capacity element.

13. The liquid crystal display device having a plurality of pixels arranged in a matrix according to claim 11, wherein the detection circuit includes a DA converter which converts the data stored in the memory element into the calibration data voltage.

14. The liquid crystal display device having a plurality of pixels arranged in a matrix according to claim 11, wherein the detection circuit includes a sample-hold circuit.

15. The liquid crystal display device having a plurality of pixels arranged in a matrix according to claim 14, wherein the detection circuit includes an A/D converter and a memory element which stores output digital data from the A/D converter.