Capacitive touch system and sensing method for a capacitive touch system

• US 8,368,660 B2
• Filed: 05/18/2009
• Issued: 02/05/2013
• Est. Priority Date: 05/19/2008
• Status: Active Grant

• Current Assignee: Elan Microelectronics Corporation
• Original Assignee: Elan Microelectronics Corporation
• Inventors: Hung, Tse-Lun, Huang, Jung-Shou, Tsai, Hsin-Shieh
• Primary Examiner(s): Beck, Alexander S
• Assistant Examiner(s): Truong, Nguyen H
• Application Number:
  US12/453,641
• Publication Number:
  US 20090284494A1
• Time in Patent Office: 1,359 Days
• Field of Search: 345/173, 178/18.01
• US Class Current: 345/173
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• 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 3/044 by capacitive means

Abstract

A capacitive touch system includes a touch panel and two touch integrated circuits connected to the touch panel to scan thereto. The touch panel has a boundary trace connected to both of the two touch integrated circuits. When one of the two touch integrated circuits charges/discharges the boundary trace, the other touch integrated circuit does not charges/discharges the boundary trace.

Claims

1. A capacitive touch system, comprising:

a touch panel having a plurality of first traces and a plurality of second traces, of which the plurality of first traces include a boundary trace;

a first touch integrated circuit connected to the plurality of first traces to charge/discharge thereto; and

a second touch integrated circuit connected to the plurality of second traces and the boundary trace to charge/discharge thereto;

wherein the first and second touch integrated circuits do not charge/discharge the boundary trace simultaneously, whereby when the boundary trace is sensed by the first touch integrated circuit a first boundary connection to the second touch integrated circuit is deactivated and the second touch integrated circuit senses the plurality of second traces, and when the boundary trace is sensed by the second touch integrated circuit a second boundary connection to the first touch integrated circuit is deactivated and the first touch integrated circuit senses the other plurality of first traces.

2. The capacitive touch system of claim 1, wherein the boundary trace is floating to the second touch integrated circuit when the first touch integrated circuit charges/discharges the boundary trace.

3. The capacitive touch system of claim 1, wherein the boundary trace has a high impedance to the second touch integrated circuit when the first touch integrated circuit charges/discharges the boundary trace.

4. The capacitive touch system of claim 1, wherein the boundary trace is floating to the first touch integrated circuit when the second touch integrated circuit charges/discharges the boundary trace.

5. The capacitive touch system of claim 1, wherein the boundary trace has a high impedance to the first touch integrated circuit when the second touch integrated circuit charges/discharges the boundary trace.

6. A sensing method for a capacitive touch system including a touch panel having a boundary trace connected to two touch integrated circuits, the sensing method comprising:

(A) deactivating a first boundary connection to between the boundary trace and the second touch integrated circuit and sensing the plurality of second traces by the second touch integrated circuit when the first touch integrated circuit charges/discharges the boundary trace; and

(B) deactivating a second boundary connection between the boundary trace and the first touch integrated circuit and sensing other the plurality of first traces by the first touch integrated circuit when the second touch integrated circuit charges/discharges the boundary trace.

7. The sensing method of claim 6, wherein the step A comprises making the boundary trace being floating to the second touch integrated circuit.

8. The sensing method of claim 6, wherein the step A comprises making the boundary trace having a high impedance to the second touch integrated circuit.

9. The sensing method of claim 6, wherein the step B comprises making the boundary trace being floating to the first touch integrated circuit.

10. The sensing method of claim 6, wherein the step B comprises making the boundary trace having a high impedance to the first touch integrated circuit.