Method, device and terminal apparatus for processing capacitance of respective layers of multi-touch panel

• US 8,593,430 B2
• Filed: 09/02/2010
• Issued: 11/26/2013
• Est. Priority Date: 09/03/2009
• Status: Expired due to Fees

• Current Assignee: Chip and System Technology Limited
• Original Assignee: Chip and System Technology Limited
• Inventors: Lee, Tat Wa, Chan, Peng Fai, Dong, Shi Ki, Tsui, Ping Fong, Li, Chin Sing
• Primary Examiner(s): FARAGALLA, MICHAEL A
• Application Number:
  US12/874,506
• Publication Number:
  US 20110050637A1
• Time in Patent Office: 1,181 Days
• Field of Search: 345/173, 345/174, 345/178, 345/175, 345/420, 345/428
• 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 device and a terminal apparatus for processing capacitance of respective layers of a multi-touch panel in the field of multi-touch panels. The method includes scanning to capture capacitance values detected by respective sensors of each layer of the multi-touch panel when the multi-touch panel is touched at multiple positions, and processing the captured capacitance values; converting the processed capacitance values into respective digital capacitance parameters; processing the respective digital capacitance parameters. The invention has the advantageous effect that the capacitance of each layer of the multi-touch panel could be detected and controlled such that the capacitance of each layer falls within a consolidated and controllable range, thereby ensuring an accurate and reliable positioning of multiple simultaneous finger touch on the panel.

Claims

1. A device for processing capacitance of a plurality of layers of a multi-touch panel, wherein each layer of the multi-touch panel has a plurality of sensors, comprising:

a plurality of capacitance processing units, each of which being coupled with a plurality of sensors of a respective layer of the multi-touch panel such that each of the capacitance processing unit scans to capture capacitance values detected by the respective sensors of the corresponding layer when the multi-touch panel is touched at multiple positions, and then processes the captured capacitance values, wherein the detected capacitance value is the summation of an intrinsic capacitance value of the corresponding layer and a capacitance variation of the corresponding layer, the intrinsic capacitance value is formed between a surface of the sensor and a surface of the panel, the capacitance variation is a result of the touch on the sensor of the corresponding layer, and wherein each capacitance processing unit processes the captured capacitance values of each layer by eliminating the intrinsic capacitance value such that the processed capacitance values comprises mainly the capacitance variation;

a plurality of capacitance converting units, each of which being correspondingly coupled with one of the capacitance processing units for converting the capacitance values processed by the capacitance processing unit into respective digital capacitance parameter outputs; and

an analyzing and processing unit for analyzing and processing the digital capacitance parameter outputs in order to determine multiple touch positions on the multi-touch panel, wherein the capacitance values of each layer of the multi-touch panel is processed independently, such that the capacitance values of each layer are compensated separately when the panel is touched.

2. The device according to claim 1, wherein the device further comprises a plurality of parameter amplification units, each of which having an input end coupled with one of the capacitance processing units and an output end coupled with one of the capacitance converting units so as to amplify the capacitance values processed by the capacitance processing unit by a predetermined ratio and to deliver the amplified capacitance values to the capacitance converting unit for effecting the conversion.

3. The device according to claim 2, wherein the plurality of the capacitance processing units scan to capture the capacitance values in a predetermined time interval on a value-by-value basis, the capacitance values being detected by the respective sensors of the corresponding layer.

4. The device according to claim 1, wherein the device further comprises a storage unit for storing the digital capacitance parameter outputs.

5. A terminal apparatus, comprising:

a multi-touch panel on which multiple touch positions are detected;

a device for processing capacitance of a plurality of layers of the multi-touch panel wherein each layer of the multi-touch panel has a plurality of sensors, comprising;

a plurality of capacitance processing units, each of which being coupled with a plurality of sensors of a respective layer of the multi-touch panel such that each of the capacitance processing unit scans to capture capacitance values detected by the respective sensors of the corresponding layer when the multi-touch panel is touched at multiple positions, and then processes the captured capacitance values, wherein the detected capacitance value is the summation of an intrinsic capacitance value of the corresponding layer and a capacitance variation of the corresponding layer, the intrinsic capacitance value is formed between a surface of the sensor and a surface of the panel, the capacitance variation is a result of the touch on the sensor of the corresponding layer, and wherein each capacitance processing unit processes the captured capacitance values of each layer by eliminating the intrinsic capacitance value such that the processed capacitance values comprises mainly the capacitance variation;

a plurality of capacitance converting units, each of which being correspondingly coupled with one of the capacitance processing units for converting the capacitance values processed by the capacitance processing unit into respective digital capacitance parameter outputs; and

an analyzing and processing unit for determining multiple touch positions on the multi-touch panel as a result of analyzing and processing the digital capacitance parameter outputs,

wherein the capacitance values of each layer of the multi-touch panel is processed independently, such that the capacitance values of each layer are compensated separately when the panel is touched.

6. The terminal apparatus according to claim 5, wherein the device for processing capacitance of respective layers of the multi-touch panel further comprises a storage unit for storing the digital capacitance parameter outputs.

7. The terminal apparatus according to claim 6, wherein the device for processing capacitance of respective layers of the multi-touch panel further comprises a plurality of amplification units for amplifying the processed capacitance values by a predetermined ratio before effecting the conversion.

8. A method for processing capacitance of a plurality of layers of a multi-touch panel wherein each layer of the multi-touch panel has a plurality of sensors, comprising steps of:

scanning to capture capacitance values detected by respective sensors of each layer of the multi-touch panel when the multi-touch panel is touched at multiple positions, and processing the captured capacitance values, wherein the detected capacitance value is the summation of an intrinsic capacitance value of the corresponding layer and a capacitance variation of the corresponding layer, the intrinsic capacitance value is formed between a surface of the sensor and a surface of the panel, the capacitance variation is a result of the touch on the sensor of the corresponding layer, and wherein each capacitance processing unit processes the captured capacitance values of each layer by eliminating the intrinsic capacitance value such that the processed capacitance values comprises mainly the capacitance variation;

converting the processed capacitance values into respective digital capacitance parameters which are then analyzed and processed to determine the multiple touch positions on the multi-touch panel,

wherein the capacitance values of each layer of the multi-touch panel is processed independently, such that the capacitance values of each layer are compensated separately when the panel is touched.

9. The method according to claim 8, further comprising the step of amplifying the processed capacitance values by a predetermined ratio prior to the step of converting the processed capacitance values into the respective digital capacitance parameters.

10. The method according to claim 9, wherein the capacitance values captured in the scanning step are detected by the respective sensors of each layer of the multi-touch panel and scanned in a predetermined time interval on a value-by-value basis.