DISPLAY DEVICE

• US 20130278516A1
• Filed: 03/27/2013
• Published: 10/24/2013
• Est. Priority Date: 04/19/2012
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display East Incorporated (Japan Display Incorporated)
• Inventors: NAGATA, Koji, DOI, Koji
• Granted Patent: US 8,878,768 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• 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 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• 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 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• 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

Abstract

Provided is a display device that includes a display panel; and a touch panel integrated in the display panel, wherein the touch panel has a plurality of scanning electrodes, a plurality of detection electrodes that intersects with the plurality of scanning electrodes, drive signal supply unit for inputting a drive signal to each of the scanning electrodes, detection unit for acquiring a detection signal from each of the detection electrodes, touch position detection unit for detecting a touch position of an detection object based on the detection signal when the drive signal is sequentially input to each of the scanning electrodes from the drive signal supply unit, and approach detection unit for detecting that the detection object approaches the touch panel based on the detection signal when a scanning voltage is collectively input to all of the scanning electrodes from the drive signal supply unit.

Claims

1. A display device comprising:

a display panel; and

a touch panel integrated in the display panel,

wherein the touch panel has

a plurality of scanning electrodes formed on the display panel,

a plurality of detection electrodes that is formed on the display panel and intersects with the plurality of scanning electrodes,

drive signal supply unit for inputting a drive signal to each of the scanning electrodes,

detection unit for acquiring a detection signal from each of the detection electrodes,

touch position detection unit for detecting a touch position of an detection object based on the detection signal detected from each of the detection unit when the drive signal is sequentially input to each of the scanning electrodes from the drive signal supply unit, and

approach detection unit for detecting that the detection object approaches the touch panel based on the detection signal detected from each of the detection unit when a scanning voltage is collectively input to all of the scanning electrodes from the drive signal supply unit.

2. The display device according to claim 1,

wherein the drive signal supply unit has

a switching element S1 that supplies a drive voltage Vtxh to each of the plurality of scanning electrodes, and

a switching element S2 that supplies a drive voltage Vtxl (Vtxl<

Vtxh) to each of the plurality of scanning electrodes,

the detection unit has

an integration circuit in which a reference voltage Vref is input to one terminal,

a switching element S3 that is connected between each of the detection electrodes and the other terminal of the integration circuit, and

a switching element S4 that is connected between each of the detection electrodes and the one terminal of the integration circuit,

the switching element S1 and the switching element S2 are provided for each of the scanning electrodes, and

the integration circuit, the switching element S3 and the switching element S4 are provided for each of the detection electrodes.

3. The display device according to claim 2,

wherein a touch position detection period of the detection object has a reset period and a detection period for each of the scanning electrodes,

in the reset period in a scanning electrode of a scanning target to which the drive signal is input, the switching element S1 of the scanning electrode of the scanning target is turned off, the switching element S2 of the scanning electrode of the scanning target is turned on, the switching element S1 and the switching element S2 of the scanning electrode other than the scanning target are turned off, the switching elements S3 of all the detection electrodes are turned off, and the switching elements S4 of all the detection electrodes are turned on, the capacity between the scanning electrode of the scanning target and all the detection electrodes is charged with a voltage of (Vref - Vtxl),

in the detection period, the switching element S1 of the scanning electrode of the scanning target is turned on, the switching element S2 of the scanning electrode of the scanning target is turned off, the switching element S1 and the switching element S2 of the scanning electrode other than the scanning target are turned off, all the switching elements S3 are turned on, all the switching elements S4 are turned off, and the electric current flowing in the capacity between the scanning electrode of the scanning target and all the detection electrodes is integrated by the integration circuit provided for each of the detection electrodes, and

the touch position detection unit detects the touch position of the detection object, based on the output voltage of the integration circuit provided for each of the detection electrodes.

4. The display device according to claim 2,

wherein the approach detection period of the object to the detected has a reset period, a charge period, and a detection period,

in the reset period, the switching elements S1 of all the scanning electrodes are turned off, the switching elements S2 of all the scanning electrode are turned on, the switching elements S3 of all the detection electrodes are turned off, and the switching elements S4 of all the detection electrodes are turned on, and the capacity between all the scanning electrodes and all the detection electrodes is charged with a voltage of (Vref - Vtxl),

in the charge period, the switching elements S1 of all the scanning electrodes are turned on, the switching elements S2 of all the scanning electrodes are turned off, the switching elements S3 of all the detection electrodes are turned off, and the switching elements S4 of all the detection electrodes are turned off, and the capacity between all the scanning electrodes and each of the detection electrodes is charged with a voltage of (Vref−

Vtxl+Vtxh),

in the detection period, the switching elements S1 of all the scanning electrodes are turned on, the switching elements S2 of all the scanning electrodes are turned off, the switching elements S3 of all the detection electrodes are turned on, and the switching elements S4 of all the detection electrodes are turned off, and the capacity between all the scanning electrodes and each of the detection electrodes is integrated by the integration circuit provided for each of the detection electrodes, and

the approach detection unit detects that the detection object approaches, based on the output voltage of the integration circuit provided for each of the detection electrodes.

5. The display device according to claim 1,

wherein the plurality of scanning electrodes and the plurality of detection electrodes are formed on different surfaces.

6. The display device according to claim 1,

wherein one electrode of the plurality of scanning electrodes and the plurality of detection electrodes is formed on a surface of an observer side of the display panel, and

the other electrode of the plurality of scanning electrodes and the plurality of detection electrodes is formed on the inside of the display panel.

7. The display device according to claim 1,

wherein the display panel is a liquid crystal display panel that has a first substrate, a second substrate, and a liquid crystal layer interposed between the first substrate and the second substrate,

the second substrate is placed on the observer side,

one electrode of the plurality of scanning electrodes and the plurality of detection electrodes is formed on a surface of an opposite side to the liquid crystal layer of the second substrate, and

the other electrode of the plurality of scanning electrodes and the plurality of detection electrodes is formed on a surface of the liquid crystal layer side of the first substrate.

8. The display device according to claim 1,

wherein the plurality of scanning electrodes and the plurality of detection electrodes are stripe-shaped electrodes.