Touch sensing method and touch sensing apparatus of charge distribution type

• US 9,110,544 B2
• Filed: 05/18/2012
• Issued: 08/18/2015
• Est. Priority Date: 12/09/2011
• Status: Active Grant

• Current Assignee: Nuvoton Technology Corporation (Winbond Electronics Corporation)
• Original Assignee: Nuvoton Technology Corporation (Winbond Electronics Corporation)
• Inventors: Chang, Yu-Cheng, Wen, Ya-Nan
• Primary Examiner(s): Lee, Jr., Kenneth B
• Application Number:
  US13/474,721
• Publication Number:
  US 20130147759A1
• Time in Patent Office: 1,187 Days
• Field of Search: None
• US Class Current: 1/1
• 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

A touch sensing method of charge distribution type is disclosed. Firstly, charges in a panel are removed. Next, a scanning signal is provided to scan a plurality of sensing regions of the panel. Subsequently, the panel is set in a first switching mode for charging the panel with the scanning signal. Thereafter, the panel is set in a second switching mode for modifying a distribution of charges injected into the panel. Next, an equivalent voltage is acquired after the charges are distributed at an equilibrium state. Furthermore, a touch sensing apparatus with charge distribution type is provided herein.

Claims

1. A touch sensing method of charge distribution type, comprising:

removing charges in a panel;

providing a scanning signal to scan a plurality of sensing regions on the panel;

setting the panel in a first switching mode for charging the panel with the scanning signal;

setting the panel in a second switching mode for modifying distribution of charges injected into the panel;

acquiring an equivalent voltage after the injected charges are distributed at an equilibrium state;

determining whether the step of scanning the sensing regions of the panel is completed so as to decide whether the acquired equivalent voltage is determined;

when the step of scanning the sensing regions is completed, determining whether an object is in contact with or close to the panel according to a variation of the equivalent voltage; and

when the step of scanning the sensing region is not completed, performing a scanning process for a next sensing region of the sensing regions,

wherein when the object is in contact with or close to the panel, a plurality of sensing paths are formed between the object and the panel such that the charges are redistributed, thus resulting in the variation of the equivalent voltage.

2. The touch sensing method of claim 1 wherein the scanning signal comprises a plurality of voltage levels.

3. The touch sensing method of claim 2, wherein charges are injected into and distributed in the panel in a positive charge distribution mode according to the scanning signal.

4. The touch sensing method of claim 3, wherein when the panel is set in the first switching mode, charges are injected into a sensing capacitor of the scanned sensing regions and an equivalent parasitic capacitor of the panel according to the scanning signal.

5. The touch sensing method of claim 4, wherein when the panel is set in the second switching mode, the charges injected into the sensing capacitor and the equivalent parasitic capacitor are redistributed in the sensing capacitor, the equivalent parasitic capacitor and an equivalent sensing capacitor of the sensing regions that are not scanned.

6. The touch sensing method of claim 2, wherein charges are injected into and distributed in the panel in a negative charge distribution mode according to the scanning signal.

7. The touch sensing method of claim 6, wherein when the panel is set in the first switching mode, charges are injected into a sensing capacitor of the scanned sensing region according to the scanning signal.

8. The touch sensing method of claim 7, wherein when the panel is set in the second switching mode, the charges injected in the sensing capacitor are redistributed in the sensing capacitor, an equivalent parasitic capacitor of the panel and an equivalent sensing capacitor of the sensing regions that are not scanned.

9. The touch sensing method of claim 6, wherein when the panel is set in the first switching mode, the injected charges are injected into an equivalent sensing capacitor of the sensing regions that are not scanned according to the scanning signal.

10. The touch sensing method of claim 9, wherein when the panel is set in the second switching mode, the charges injected in the equivalent sensing capacitor are redistributed in a sensing capacitor of the scanned sensing region, an equivalent parasitic capacitor of the panel and the equivalent sensing capacitor.

11. The touch sensing method of claim 6, wherein when the panel is set in the first switching mode, all of the charges in a sensing capacitor of the scanned sensing regions, an equivalent parasitic capacitor of the panel and an equivalent sensing capacitor of the sensing regions that are not scanned, are removed according to the scanning signal.

12. The touch sensing method of claim 11, wherein when the panel is set in the second switching mode, charges are injected and distributed in the sensing capacitor, the equivalent parasitic capacitor and the equivalent sensing capacitor with the scanning signal.

13. The touch sensing method with charge distribution of claim 1, wherein the step of setting the panel in the first switching mode for charging the panel according to the scanning signal further comprises:

charging a sensing capacitor of the scanned sensing regions, an equivalent parasitic capacitor of the panel and an equivalent sensing capacitor of the sensing regions that are not scanned to a relatively low voltage level or a zero voltage level.

14. A touch sensing apparatus of charge distribution type, comprising:

a plurality of first axial electrodes disposed in a panel;

a plurality of second axial electrodes disposed in the panel, the second axial electrodes interlaced or interleaved with the first axial electrodes to form a plurality of sensing regions;

a first axial switch unit electrically coupled with the first axial electrodes;

a second axial switch unit electrically coupled with the second axial electrodes;

a switch control unit which is electrically coupled between the first axial switch unit and the second axial switch unit and is configured to control switching modes of the first axial switch unit and the second axial switch unit such that charges are injected into and distributed in the panel according to a scanning signal;

a measurement unit electrically coupled with the first axial switch unit to acquire an equivalent voltage after the charges are distributed at an equilibrium state; and

a processing unit which is electrically coupled with the measurement unit and the switch control unit and is configured to determine whether an object is in contact with or close to the panel according to a variation of the equivalent voltage acquired by the measurement unit,

wherein the scanning signal comprises a plurality of voltage levels, the charges are injected into and distributed in the panel in a negative charge distribution mode according to the scanning signal, and when the panel is set in a first switching mode, the injected charges are injected into an equivalent sensing capacitor of the sensing regions that are not scanned according to the scanning signal;

when the panel is set in the second switching mode, the charges injected in the equivalent sensing capacitor are redistributed in a sensing capacitor of the scanned sensing region, an equivalent parasitic capacitor of the panel and the equivalent sensing capacitor.

15. The touch sensing apparatus of claim 14, wherein the panel is a touch panel, and the first axial electrodes are disposed on an outer or inner surface of a glass substrate of the touch panel, and the second axial electrodes are disposed on the outer or inner surface of the glass substrate of the touch panel.

16. The touch sensing apparatus of claim 14, wherein the panel is a display panel, and the first axial electrodes are located in the display panel or on a surface of the display panel, and the second axial electrodes are located in the display panel or on the surface of the display panel.

17. A touch sensing method of charge distribution type, comprising:

removing charges in a panel;

providing a scanning signal to scan a plurality of sensing regions on the panel;

setting the panel in a first switching mode for charging the panel with the scanning signal;

setting the panel in a second switching mode for modifying a distribution of charges injected into the panel; and

acquiring an equivalent voltage after the injected charges are distributed at an equilibrium state,

wherein the scanning signal comprises a plurality of voltage levels, charges are injected into and distributed in the panel in a negative charge distribution mode according to the scanning signal, and when the panel is set in the first switching mode, charges are injected into a sensing capacitor of the scanned sensing region according to the scanning signal;

when the panel is set in the second switching mode, the charges injected in the sensing capacitor are redistributed in the sensing capacitor, an equivalent parasitic capacitor of the panel and an equivalent sensing capacitor of the sensing regions that are not scanned.