CAPACITIVE TOUCH PANEL, DRIVING METHOD FOR PREVENTING LEAKAGE CURRENT

• US 20130135249A1
• Filed: 06/01/2012
• Published: 05/30/2013
• Est. Priority Date: 11/25/2011
• Status: Abandoned Application

• Current Assignee: SHIH Hua Technology Limited
• Original Assignee: SHIH Hua Technology Limited
• Inventors: CHEN, PO-YANG, SHIH, PO-SHENG, CHENG, CHIEN-YUNG, KUO, FENG-YU, HUANG, CHUN-LUNG
• Application Number:
  US13/486,662
• Publication Number:
  US 20130135249A1
• Time in Patent Office: Days
• US Class Current: 345/174
• 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

Abstract

A capacitive touch panel includes a substrate; a transparent conductive layer with anisotropic impedance located on the substrate; a plurality of driving sensing electrodes located on the opposite two sides of the transparent conductive layer; at least one sensing unit connected to the plurality of driving sensing electrodes for scanning the plurality of driving sensing electrodes; at least one voltage compensation unit which provides a offset voltage, at least one voltage compensation unit has a first end and a second end, the first end of at least one voltage compensation unit is at least connected to one of the plurality of driving sensing electrodes, the second end of at least one voltage compensation unit is connected to a grounding voltage. The present application also relates to a driving method for preventing leakage current of the capacitive touch panel.

Claims

1. A capacitive touch panel, comprising:

a substrate;

a transparent conductive layer with anisotropic impedance located on the substrate, a lower impedance direction D and a higher impedance direction H are defined on the transparent conductive layer, the lower impedance direction D is perpendicular to the higher impedance direction H;

a plurality of driving sensing electrodes located on the two opposite sides of the transparent conductive layer, the plurality of driving sensing electrodes is located along a direction perpendicular to the lower impedance direction D;

at least one sensing unit connected to the plurality of driving sensing electrodes for scanning the plurality of driving sensing electrodes;

wherein the capacitive touch panel comprises at least one voltage compensation unit configured to provide an offset voltage, and the at least one voltage compensation unit comprises a first end and a second end, the first end of at least one voltage compensation unit is connected to at least one of the plurality of driving sensing electrodes, the second end of at least one voltage compensation unit is connected to a grounding voltage.

2. The capacitive touch panel of claim 1, wherein each of the plurality of driving sensing electrodes is simultaneously connected to one sensing unit and one voltage compensation unit, and the at least one sensing unit and the at least one voltage compensation unit are connected in parallel.

3. The capacitive touch panel of claim 1, wherein one sensing unit is sequentially connected to each of the plurality of driving sensing electrodes, when one of the plurality of driving sensing electrodes is connected to the at least one sensing unit, the rest of the plurality of driving sensing electrodes are connected to the at least one voltage compensation unit.

4. The capacitive touch panel of claim 1, wherein the at least one voltage compensation unit is a power supply.

5. The capacitive touch panel of claim 4, wherein the power supply is a capacitor.

6. The capacitive touch panel of claim 1, wherein the at least one sensing unit comprises a charge circuit, a storage circuit and a read-out circuit;

the charge circuit and the storage circuit are connected in parallel; and

the read-out circuit is connected to the storage circuit.

7. The capacitive touch panel of claim 1, wherein if the plurality of driving sensing electrodes is scanned, the plurality of driving sensing electrodes is connected to the at least one sensing unit;

if the plurality of driving sensing electrodes is not scanned, the plurality of driving sensing electrodes is connected to the at least one voltage compensation unit.

8. The capacitive touch panel of claim 1, wherein the transparent conductive layer is a carbon nanotube layer comprises a carbon nanotube film or a plurality of carbon nanotube films overlapped with each other.

9. The capacitive touch panel of claim 8, wherein the carbon nanotube film comprises a plurality of carbon nanotubes parallel to each other, and the plurality of carbon nanotubes is oriented along a preferred orientation.

10. The capacitive touch panel of claim 8, wherein the carbon nanotube film comprises a plurality of carbon nanotube bundles oriented along a preferred orientation, and the plurality of carbon nanotube bundles joins end-to-end by van der Waals attractive force and forms a continuous carbon nanotube film.

11. The capacitive touch panel of claim 1, wherein a length of each of the plurality of driving sensing electrodes is in a range from about 1 mm to about 5 mm, and a distance between the adjacent two driving sensing electrodes is in a range from about 1 mm to about 5 mm.

12. A driving method for driving a capacitive touch panel, comprising steps of:

providing a capacitive touch panel, the capacitive touch panel comprises a transparent conductive layer with anisotropic impedance located on the substrate, a lower impedance direction D and a higher impedance direction H are defined on the transparent conductive layer, the lower impedance direction D is perpendicular to the higher impedance direction H;

a plurality of driving sensing electrodes located on the two opposite sides of the transparent conductive layer, the plurality of driving sensing electrodes is located along a direction perpendicular to the lower impedance direction D;

at least one sensing unit connected to the plurality of driving sensing electrodes for scanning the plurality of driving sensing electrodes, and the at least one sensing unit comprises a read-out circuit;

at least one voltage compensation unit is configured to provide an offset voltage and comprises a first end and a second end, the first end of at least one voltage compensation unit is connected to at least one of the plurality of driving sensing electrodes, the second end of at least one voltage compensation unit is connected to a grounding voltage;

sensing an input touch on the transparent conductive layer, and forming a touch capacitance;

sequentially scanning the plurality of driving sensing electrodes by the at least one sensing unit;

in process of scanning each of the plurality of driving sensing electrodes, providing an offset voltage by the rest of the plurality of driving sensing electrodes thought the at least one voltage compensation unit; and

determining an input touch position by a charge parameter of the touch capacitance which is read out by the read-out circuit.

13. The driving method of claim 12, wherein the at least one sensing unit comprises a charge circuit, a storage circuit and the read-out circuit, the charge circuit and the storage circuit are connected in parallel, the read-out circuit is connected to the storage circuit.

14. The driving method of claim 13, wherein providing driving voltage by the charge circuit, the driving voltage is defined as V_i, the offset voltage is defined as V_Background, and the V_Background is greater than 0 and less than 2V_i.

15. The driving method of claim 12, wherein each of the plurality of driving sensing electrodes is simultaneously connected to one sensing unit and one voltage compensation unit, and the at least one sensing unit and the at least one voltage compensation unit are connected in parallel.

16. The driving method of claim 12, wherein one sensing unit is sequentially connected to each of the plurality of driving sensing electrodes;

and when one of the plurality of driving sensing electrodes is connected to the at least one sensing unit, the rest of the plurality of driving sensing electrodes are connected to the at least one voltage compensation unit.

17. The driving method of claim 12, wherein the at least one voltage compensation unit is a power supply.

18. The driving method of claim 12, wherein when the plurality of driving sensing electrodes is scanned, the plurality of driving sensing electrodes is connected to the at least one sensing unit;

and when the plurality of driving sensing electrodes is not scanned, the plurality of driving sensing electrodes is connected to the at least one voltage compensation unit.