DISPLAY DEVICE AND ELECTRONIC UNIT

• US 20100295824A1
• Filed: 04/22/2010
• Published: 11/25/2010
• Est. Priority Date: 05/21/2009
• Status: Active Grant

• Current Assignee: Japan Display West Incorporated (Japan Display Incorporated)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: TERANISHI, Yasuyuki, ISHIZAKI, Koji, NAKANISHI, Takayuki, NOGUCHI, Kouji, TAKEUCHI, Takeya
• Granted Patent: US 8,976,123 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/134372 for fringe field switching [FFS] where the common electrode is not patterned
• CPC Class Codes: G02F 2201/121 common or background
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• 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
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 5/18 Timing circuits for raster scan displays specially adapted for television H04N ; synchronisation between the display unit and other display units, videodisc player G09G5/12

Abstract

The display device with high detection accuracy includes: display pixel electrodes; a common electrode; a display function layer; a display control circuit performing image display control by applying a pixel voltage to each of the display pixel electrodes and applying a common drive voltage to the common electrode, the common drive voltage inverting in synchronization with a drive cycle of the image display control; a touch detection electrode cooperating with the common electrode to form a capacitor; and a touch detection circuit detecting an external proximity object, based on a detection signal obtained from the touch detection electrode in response to the common drive voltage applied to the common electrode. The touch detection circuit corrects the detection signal based on a gray scale of the image signal at the time of acquisition of the detection signal, and performs the detection operation.

Claims

1. A display device, comprising:

a plurality of display pixel electrodes;

a common electrode provided to oppose the display pixel electrodes;

a display function layer having an image display function;

a display control circuit performing image display control by applying a pixel voltage based on an image signal to each of the display pixel electrodes and applying a common drive voltage to the common electrode, the common drive voltage inverting in synchronization with a drive cycle of the image display control;

a touch detection electrode cooperating with the common electrode to form a capacitor; and

a touch detection circuit performing a detection operation of detecting an external proximity object, based on a detection signal obtained from the touch detection electrode in response to the common drive voltage applied to the common electrode,

wherein the touch detection circuit corrects the detection signal based on a gray scale of the image signal at the time of acquisition of the detection signal, and performs the detection operation.

2. The display device according to claim 1, wherein

the touch detection circuit corrects the detection signal obtained from the touch detection electrode with use of the image signal and reference noise data, the reference noise data being configured of a gray scale value of the image signal and a detection signal value which are correlated with each other, the value of the detection signal including internal noise resulted from an image-signal writing operation for image display with the gray scale value.

3. The display device according to claim 2, wherein

the touch detection circuit prepares a correction table configured of gray scale values of the image signals actually inputted and the detection signal values given by the reference noise data which are correlated with each other, for every predetermined pixel region including predetermined number of the display pixel electrodes, and

the touch detection circuit corrects the detection signal obtained from the touch detection electrode with use of the correction table.

4. The display device according to claim 3, wherein

the touch detection circuit generates a correction signal for the detection signal obtained from the touch detection electrode through performing, for each of the pixel regions, a subtraction or division between the value of the detection signal in the correction table and the value of the detection signal obtained from the touch detection electrode.

5. The display device according to claim 3, wherein

the common electrode and the touch detection electrode are each divided into a plurality of electrode patterns each having a stripe shape, and

the pixel region has a horizontal length equal to a stripe pitch of the electrode patterns configuring the touch detection electrode, and has a vertical length equal to a width of the electrode pattern in the common electrode, each of the electrode patterns configuring the touch detection electrode locating in a center of the horizontal length.

6. The display device according to claim 5, wherein

the touch detection circuit re-corrects the detection signal obtained from the touch detection electrode in each of the pixel regions along a horizontal line, utilizing a correction result in all of the pixel regions along the horizontal line.

7. The display device according to claim 2, wherein

the touch detection circuit corrects the detection signal obtained from the touch detection electrode through normalizing, for each of the pixel regions, the value of the detection signal obtained from the touch detection electrode with use of the value of the detection signal in the reference noise data corresponding to the gray scale value of the image signal.

8. The display device according to claim 7, wherein

the common electrode and the touch detection electrode are each divided into a plurality of electrode patterns each having a stripe shape, and

the pixel region has a horizontal length equal to a stripe pitch of the electrode patterns configuring the touch detection electrode, and has a vertical length equal to a width of the electrode pattern in the common electrode, each of the electrode patterns configuring the touch detection electrode locating in a center of the horizontal length.

9. The display device according to claim 8, wherein

the touch detection circuit re-corrects the detection signal obtained from the touch detection electrode in each of the pixel regions along a horizontal line, utilizing results of corrections performed separately in all of the pixel regions along the horizontal line.

10. The display device according to claim 2, wherein

the reference noise data is data created, in a blanking period between effective display periods, based on an internal-noise detection signal obtained from the touch detection electrode in response to a predetermined pattern signal for detection supplied by the display control circuit.

11. The display device according to claim 10, wherein

the display control circuit supplies an image signal of a predetermined gray scale as the detection pattern signal to the pixel electrode, and

the touch detection circuit acquires the internal-noise detection signal in correspondence with the predetermined gray scale.

12. The display device according to claim 11, wherein

the display control circuit supplies a plurality of image signals of various gray scales each as the detection pattern signal to the pixel electrode in the blanking periods repeated for a plurality of times, respectively, and

the touch detection circuit acquires the internal-noise detection signals in correspondence with the various gray scales, respectively.

13. The display device according to claim 2, wherein

the reference noise data is experimental data pre-acquired through a predetermined experiment.

14. The display device according to claim 1, wherein

the common electrode is divided into a plurality of electrode patterns each having a stripe shape.

15. The display device according to claim 14, wherein

the display control circuit drives the plurality of electrode patterns in such a manner that a group of electrode patterns selected from the plurality of electrode patterns are driven at a time, the selection of the several electrode patterns being sequentially shifted.

16. The display device according to claim 1, further comprising:

a circuit substrate with the display control circuit therein; and

an opposed substrate facing the circuit substrate,

wherein the display pixel electrodes are disposed on a side close to the opposed substrate, on the circuit substrate,

the common electrode is disposed on a side close to the circuit substrate, on the opposed substrate, and

the display function layer is disposed to be inserted between the display pixel electrode on the circuit substrate and the common electrode on the opposed substrate.

17. The display device according to claim 16, wherein the display function layer is a liquid crystal layer.

18. The display device according to claim 1, further comprising:

a circuit substrate with the display control circuit therein; and

an opposed substrate facing the circuit substrate,

wherein the common electrode and the display pixel electrode are stacked in order, with an insulating layer in between, on the circuit substrate, and

the display function layer is disposed to be inserted between the display pixel electrode on the circuit substrate and the opposed substrate.

19. The display device according to claim 18, wherein the display function layer is a liquid crystal layer which operates in a lateral-electric-field mode.

20. An electronic unit, comprising:

a touch-sensor-provided display device, the display device including;

a plurality of display pixel electrodes;

a common electrode provided to oppose the display pixel electrodes;

a display function layer having an image display function;

a display control circuit performing image display control by applying a pixel voltage based on an image signal to each of the display pixel electrodes and applying a common drive voltage to the common electrode, the common drive voltage inverting in synchronization with a drive cycle of the image display control;

a touch detection electrode cooperating with the common electrode to form a capacitor; and

a touch detection circuit performing a detection operation of detecting an external proximity object, based on a detection signal obtained from the touch detection electrode in response to the common drive voltage applied to the common electrode,

wherein the touch detection circuit corrects the detection signal based on a gray scale of the image signal at the time of acquisition of the detection signal, and performs the detection operation.