DISPLAY APPARATUS WITH TOUCH SENSING FUNCTION

• US 20140204049A1
• Filed: 04/15/2013
• Published: 07/24/2014
• Est. Priority Date: 01/18/2013
• Status: Abandoned Application

• Current Assignee: HannStar Display Corporation
• Original Assignee: HannStar Display Corporation
• Inventors: Tsai, Kun-Hua, Lee, Hsing-Ying, Su, Ping-Yuan, Lin, Yu-Cheng
• Application Number:
  US13/862,487
• Publication Number:
  US 20140204049A1
• Time in Patent Office: Days
• US Class Current: 345/174
• 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 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer

Abstract

The invention provides a display apparatus including a display panel, a display driving circuit and a touch sensing circuit. The display panel has a plurality of pixels arranged in an array, in which each of the pixels includes a liquid crystal capacitor. The display driving circuit is coupled to the display panel and configured to drive the pixels during a display period in a frame period to display images on the display panel. The touch sensing circuit is coupled to the display panel and configured to sense capacitance variations of the liquid crystal capacitors during a blanking period in the frame period, so as to generate a touch information.

Claims

1. A display apparatus with touch sensing function, comprising:

a display panel having a plurality of pixels arranged in an array, and each of the pixels comprises a liquid crystal capacitor;

a display driving circuit coupled to the display panel and configured to drive the pixels during a display period in a frame period to display images on the display panel; and

a touch sensing circuit coupled to the display panel and configured to sense capacitance variations of the liquid crystal capacitors during a blanking period in the frame period thereby generating a touch information.

2. The display apparatus with touch sensing function of claim 1, wherein the display panel further comprises a plurality of patterned common electrodes and each of the pixels further comprises a pixel electrode.

3. The display apparatus with touch sensing function of claim 2, wherein the patterned common electrodes are respectively overlapped with a part of the pixel electrodes, and the liquid crystal capacitors are respectively built by each of the pixel electrodes with the patterned common electrodes overlapped thereto.

4. The display apparatus with touch sensing function of claim 2, wherein the display panel further comprises a plurality of scan lines and a plurality of data lines, the pixels are respectively coupled to the corresponding scan lines and the corresponding data lines, and the display driving circuit comprises:

a gate driver coupled to the scan lines and configured to turn-on the pixels on the scan lines sequentially during the display period, and turn-on the pixels simultaneously during the blanking period;

a source driver configured to provide a plurality of pixel voltages to drive the pixels collaboratively with the gate driver; and

a timing controller coupled to the gate driver and the source driver and configured to control operations of the gate driver and the source driver.

5. The display apparatus with touch sensing function of claim 4, wherein the source driver provides an initial voltage to driver the pixels during an initialization of the blanking period to initialize the liquid crystal capacitors.

6. The display apparatus with touch sensing function of claim 4, wherein the gate driver is controlled by the timing controller to turn-on the scan lines with a first sequence during a first display period in a first frame period.

7. The display apparatus with touch sensing function of claim 6, wherein the gate driver is controlled by the timing controller to turn-on the scan lines with a second sequence being different to the first sequence during a second display period in a second frame period.

8. The display apparatus with touch sensing function of claim 4, wherein the touch sensing circuit comprising:

a driving unit configured to provide a scan signal to the patterned common electrodes sequentially during the blanking period for each row of the pixels to generate a plurality of sensing signals in response to the scan signal; and

a sensing unit configured to receive the sensing signals during the blanking period and generate the touch information according to the sensing signals.

9. The display apparatus with touch sensing function of claim 8, wherein the display apparatus further comprising:

a bidirectional multiplexer having a terminal coupled to the source driver and the sensing unit and another terminal coupled to the scan lines of the display panel.

10. The display apparatus with touch sensing function of claim 9, wherein the bidirectional multiplexer is controlled to couple the data lines to the source driver during the display period to provide the pixel voltages respectively to the corresponding data lines.

11. The display apparatus with touch sensing function of claim 9, wherein the bidirectional multiplexer is controlled to switch the data lines to couple the sensing unit during the blanking period, thereby transmitting the sensing signals to the sensing unit through the corresponding data lines.

12. The display apparatus with touch sensing function of claim 4, wherein the display panel further comprising:

a first substrate;

a common electrode layer disposed on the first substrate, and the patterned common electrodes are disposed in the common electrode layer;

a pixel electrode layer disposed on the common electrode layer, and the pixel electrodes are disposed in the pixel electrode layer;

a liquid crystal layer disposed on the pixel electrode layer; and

a second substrate disposed on the liquid crystal layer.

13. The display apparatus with touch sensing function of claim 12, wherein the first substrate, the common electrode layer, the pixel electrode layer, the liquid crystal layer and the second substrate are stacked along a first direction, and the display panel is controlled by the display driving circuit to build an electric field along a second direction being perpendicular to the first direction.

14. The display apparatus with touch sensing function of claim 1, wherein the display panel is an in-plane switching (IPS) LCD panel.

15. The display apparatus with touch sensing function of claim 1, wherein the display panel is a fringe field switching (FFS) LCD panel.

16. A driving method for a display apparatus with touch sensing function, comprising steps of:

providing a plurality of pixels with liquid crystal capacitors;

driving a plurality of pixels during a display period in a frame period to display images; and

sensing capacitance variations of the liquid crystal capacitors during a blanking period in the frame period thereby generating a touch information.

17. The driving method for the display apparatus with touch sensing function of claim 16, further comprising a step of:

turning on the pixels sequentially during the display period and the blanking period.

18. The driving method for the display apparatus with touch sensing function of claim 16, further comprising steps of:

providing an initial voltage to the pixels during an initialization of the blanking period; and

initializing the liquid crystal capacitors.

19. The driving method for the display apparatus with touch sensing function of claim 16, further comprising steps of:

providing a scan signal to a plurality of patterned common electrodes sequentially during the blanking period for each row of the pixels; and

generating a plurality of sensing signals in response to the scan signal.

20. The driving method for the display apparatus with touch sensing function of claim 19, further comprising steps of:

receiving the sensing signals during the blanking period; and

generating the touch information according to the sensing signals.