Liquid crystal display panel and liquid crystal display apparatus

• US 8,581,863 B2
• Filed: 04/21/2010
• Issued: 11/12/2013
• Est. Priority Date: 05/29/2009
• Status: Expired due to Fees

• Current Assignee: Casio Computer Company Limited
• Original Assignee: Casio Computer Company Limited
• Inventors: Iwasaki, Makoto, Nishino, Toshiharu, Sasaki, Kazuhiro
• Primary Examiner(s): Boddie, William
• Assistant Examiner(s): Okebato, Sahlu
• Application Number:
  US12/764,317
• Publication Number:
  US 20100302227A1
• Time in Patent Office: 1,301 Days
• Field of Search: 345/173, 345/174, 345/175
• US Class Current: 345/173
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• 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: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

A liquid crystal display panel in which coordinate detection electrodes are formed on a first substrate and protruding contact portions are formed on a second substrate as a touch panel function includes a conversion circuit formed therein. The conversion circuit subjects information indicative of whether the protruding contact portions are in contact with the coordinate detection electrodes to parallel/serial conversion to output the converted information to the coordinate detection circuit.

Claims

1. A liquid crystal display panel in which pixel electrodes connected with pixel transistors are arranged to face an opposed electrode through a liquid crystal layer per each pixel and an alignment direction of liquid crystal molecules in the liquid crystal layer changes by controlling a voltage between the pixel electrodes and the opposed electrode, the liquid crystal display panel comprising:

scanning lines which extend in parallel to each other and through which ON signals for turning on respective corresponding pixel transistors during a predetermined period are supplied to the respective corresponding pixel transistors;

first coordinate detection electrodes which are arranged in a predetermined direction, wherein different pluralities of the first coordinate detection electrodes correspond to different ones of the scanning lines;

first coordinate detection transistors, one of which electrically connects one of the different pluralities of the first coordinate detection electrodes corresponding to one of the scanning lines to an output line commonly connected with the first coordinate detection transistors based on one of the ON signals supplied to the pixel transistors from said one of the scanning lines;

second coordinate detection electrodes which are arranged along parallel lines perpendicular to the predetermined direction, wherein different pluralities of the second coordinate detection electrodes correspond to different ones of the scanning lines, other than the ones of the scanning lines to which the pluralities of the first coordinate detection electrodes correspond; and

second coordinate detection transistors, one of which electrically connects one of the different pluralities of the second coordinate detection electrodes corresponding to one of the scanning lines to the output line, which is commonly connected with the second coordinate detection transistors, based on one of the ON signals supplied to the pixel transistors from said one of the scanning lines.

2. The liquid crystal display panel according to claim 1, wherein the pixel transistors, the first coordinate detection transistors, and the output line are formed on a same substrate.

3. The liquid crystal display panel according to claim 1, wherein the pixel transistors, the second coordinate detection transistors, and the output line are formed on a same substrate.

4. The liquid crystal display panel according to claim 1, further comprising:

a first substrate on which the first coordinate detection electrodes are formed; and

a second substrate which is arranged to face the first substrate and on which the opposed electrode is formed,

wherein the second substrate includes protruding contact portions which come into contact with the first coordinate detection electrodes when the second substrate undergoes flexural deformation due to pressing.

5. The liquid crystal display panel according to claim 1, further comprising a single comparator for both X coordinate detection and Y coordinate detection in an external circuit.

6. A liquid crystal display apparatus in which pixel electrodes connected with pixel transistors are arranged to face an opposed electrode through a liquid crystal layer per each pixel and an alignment direction of liquid crystal molecules in the liquid crystal layer is controlled by controlling a voltage applied to a space between the pixel electrodes and the opposed electrode, the liquid crystal display panel comprising:

a scan driver which sequentially outputs ON signals for turning on the pixel transistors during a predetermined period to scanning lines extending in parallel to each other;

first coordinate detection electrodes which are arranged in a predetermined direction, wherein different pluralities of the first coordinate detection electrodes correspond to different ones of the scanning lines;

first coordinate detection transistors, one of which electrically connects one of the different pluralities of the first coordinate detection electrodes corresponding to one of the scanning lines to an output line commonly connected with the first coordinate detection transistors based on one of the ON signals supplied to the pixel transistors from said one of the scanning lines;

second coordinate detection electrodes which are arranged along parallel lines perpendicular to the predetermined direction, wherein different pluralities of the second coordinate detection electrodes correspond to different ones of the scanning lines, other than the ones of the scanning lines to which the pluralities of the first coordinate detection electrodes correspond; and

second coordinate detection transistors, one of which electrically connects one of the different pluralities of the second coordinate detection electrodes corresponding to one of the scanning lines to the output line, which is commonly connected with the second coordinate detection transistors, based on one of the ON signals supplied to the pixel transistors from said one of the scanning lines,

wherein the pixel transistors, the first coordinate detection transistors, the second coordinate detection transistors, and the output line are formed on a same substrate.

7. The apparatus according to claim 6, further comprising a coordinate detection circuit which causes the first coordinate detection electrodes and the second coordinate detection electrodes to hold a reset voltage different from a voltage of the opposed electrode in synchronization with an output timing of the ON signals output from the scan driver.

8. The apparatus according to claim 6, further comprising a coordinate detection circuit which detects a contact position on a substrate having the opposed electrode with respect to the substrate having the first coordinate detection electrodes based on voltage information in the first coordinate detection electrodes detected through the output line.

9. The apparatus according to claim 6, wherein the substrate on which the first coordinate detection electrodes are formed is a first substrate;

wherein the apparatus further comprises a second substrate which is arranged to face the first substrate and on which the opposed electrode is formed, and

wherein the second substrate includes protruding contact portions which come into contact with the first coordinate detection electrodes when the second substrate undergoes flexural deformation due to pressing.

10. The apparatus according to claim 9, further comprising a coordinate detection circuit which detects the first coordinate detection electrode that has come into contact with the protruding contact portion based on voltage information in the first coordinate detection electrodes detected through the output line.

11. The apparatus according to claim 6, further comprising a single comparator for both X coordinate detection and Y coordinate detection in an external circuit.

12. A liquid crystal display panel in which pixel electrodes connected with pixel transistors are arranged to face an opposed electrode through a liquid crystal layer per each pixel and an alignment direction of liquid crystal molecules in the liquid crystal layer changes by controlling a voltage between the pixel electrodes and the opposed electrode, the liquid crystal display panel comprising:

scanning lines which extend in parallel to each other and through which ON signals for turning on respective corresponding pixel transistors during a predetermined period are supplied to the respective corresponding pixel transistors;

a plurality of groups of first coordinate detection electrodes which are arranged in a predetermined direction, at least two of the plurality of groups of the first coordinate detection electrodes corresponding to one of the scanning lines;

first coordinate detection transistors, one of which electrically connects said at least two of the plurality of groups of the first coordinate detection electrodes corresponding to said one of the scanning lines to an output line commonly connected with the first coordinate detection transistors based on one of the ON signals supplied to the pixel transistors from said one of the scanning lines;

a plurality of groups of second coordinate detection electrodes which are arranged along parallel lines perpendicular to the predetermined direction, at least two of the plurality of groups of the second coordinate detection electrodes corresponding to another one of the scanning lines; and

second coordinate detection transistors, one of which electrically connects said at least two of the plurality of groups of the second coordinate detection electrodes corresponding to said another one of the scanning lines to the output line, which is commonly connected with the second coordinate detection transistors, based on one of the ON signals supplied to the pixel transistors from said another one of the scanning lines.

13. A liquid crystal display apparatus in which pixel electrodes connected with pixel transistors are arranged to face an opposed electrode through a liquid crystal layer per each pixel and art alignment direction of liquid crystal molecules in the liquid crystal layer is controlled by controlling a voltage applied to a space between the pixel electrodes and the opposed electrode, the liquid crystal display apparatus comprising:

a scan driver which sequentially outputs ON signals for turning on the pixel transistors during a predetermined period to scanning lines extending in parallel to each other;

a plurality of groups of first coordinate detection electrodes which are arranged in a predetermined direction, at least two of the plurality of groups of the first coordinate detection electrodes corresponding to one of the scanning lines

first coordinate detection transistors, one of which electrically connects said at least two of the plurality of groups of the first coordinate detection electrodes corresponding to said one of the scanning lines to an output line commonly connected with the first coordinate detection transistors based on one of the ON signals supplied to the pixel transistors from said one of the scanning lines;

a plurality of groups of second coordinate detection electrodes which are arranged along parallel lines perpendicular to the predetermined direction, at least two of the plurality of groups of the second coordinate detection electrodes corresponding to another one of the scanning lines; and

second coordinate detection transistors, one of which electrically connects said at least two of the plurality of groups of the second coordinate detection electrodes corresponding to said another one of the scanning lines to the output line, which is commonly connected with the second coordinate detection transistors, based on one of the ON signals supplied to the pixel transistors from said another one of the scanning lines,

wherein the pixel transistors, the first coordinate detection transistors, the second coordinate detection transistors, and the output line are formed on a same substrate.