Touch device for determining real coordinates of multiple touch points and method thereof

• US 9,069,420 B2
• Filed: 07/06/2011
• Issued: 06/30/2015
• Est. Priority Date: 11/13/2010
• Status: Active Grant

• Current Assignee: TPK Touch Solutions (Xiamen) Inc. (TPK Holding Co., Ltd.)
• Original Assignee: TPK Touch Solutions (Xiamen) Inc. (TPK Holding Co., Ltd.)
• Inventors: Liu, Yong
• Primary Examiner(s): Sasinowski, Andrew
• Application Number:
  US13/176,749
• Publication Number:
  US 20120120006A1
• Time in Patent Office: 1,455 Days
• Field of Search: 345173-179, 178 1801- 1804
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• 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 3/0443 using a single layer of sensing electrodes
• 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 device for determining real coordinates of multiple touch points is provided. The touch device for determining real coordinates of the multiple touch points comprises a plurality of electrodes and a scanning circuit having a Normal Scanning Circuit and a Split Scanning Circuit connected to said electrodes for eliminating ghost coordinates of the multiple touch points from raw coordinates to output the real coordinates of the multiple touch points. The method of determining real coordinates of multiple touch points on the touch device is also provided.

Claims

1. A method of determining real coordinates of multiple touch points, comprising the steps of:

(a) scanning a plurality of electrodes both in a first direction and a second direction to detect raw coordinates of said touch points by a Normal Scanning Circuit, and computing centroids of changes in self capacitance corresponding to said multiple touch points in said first direction and said second direction and calculating raw coordinates of said touch points by intersecting said centroids; and

(b)scanning said plurality of electrodes to determine real coordinates of said multiple touch points from said raw coordinates by a Split Scanning Circuit, and dividing said raw coordinates into two groups when at least two said centroids are computed both in said first direction and said second direction, wherein said step (b) further comprises steps of;

(b1) scanning a plurality of first A electrodes by said Split Scanning Circuit to compute centroids of changes in self capacitance on said first A electrodes;

(b2) scanning a plurality of second A electrodes by said Split Scanning Circuit to compute centroids of changes in self capacitance on said second A electrodes when at least two said centroids are computed in said step (b1);

and

(b3) outputting said group of raw coordinates having said centroid in said step (b2) as real coordinates of said touch points.

2. The method of claim 1, wherein said step (b1) comprises scanning a plurality of first B electrodes by said Split Scanning Circuit to compute centroids of changes in self capacitance on said first B electrodes.

3. The method of claim 1, wherein said step (b2) comprises scanning a plurality of second B electrodes by said Split Scanning Circuit to compute centroids of changes in self capacitance on said second B electrodes.

4. The method of claim 1, further comprising the steps of:

(c) outputting said raw coordinates as real coordinates of said multiple touch points when only one said centroid is computed in either said first direction or said second direction in said step (b).

5. A method of determining real coordinates of multiple touch points, comprising the steps of:

(a) scanning a plurality of electrodes both in a first direction and a second direction to detect raw coordinates of said touch points by a Normal Scanning Circuit, and computing centroids of changes in self capacitance corresponding to said multiple touch points in said first direction and said second direction and calculating raw coordinates of said touch points by intersecting said centroids; and

(b)scanning said plurality of electrodes to determine real coordinates of said multiple touch points from said raw coordinates by a Split Scanning Circuit, and dividing said raw coordinates into two groups when at least two said centroids are computed both in said first direction and said second direction, wherein said step (b) further comprises steps of;

(b1) scanning a plurality of first A electrodes by said Split Scanning Circuit to compute centroids of changes in self capacitance on said first A electrodes; and

(b2) outputting said group of raw coordinates having said centroid in said step (b1) as real coordinates of said multiple touch points when only one centroid is computed in said step (1).

6. The method of claim 5, wherein said step (b1) comprises scanning a plurality of first B electrodes by said Split Scanning Circuit to compute centroids of changes in self capacitance on said first B electrodes.

7. The method of claim 5, wherein said electrodes are connected with the Normal Scanning Circuit through switches and said switches are closed when said Normal Scanning Circuit scans said electrodes.

8. The method of claim 5, wherein said plurality of electrodes comprises a plurality of said first A electrodes and a plurality of first B electrodes in the first direction and a plurality of second A electrodes and a plurality of second B electrodes in the second direction, wherein a plurality of switches connect said first A electrodes, said first B electrodes, said second A electrodes. and said second B electrodes to a processor, wherein only switches connected to first A electrodes, or first B electrodes, or second A electrodes, or second B electrodes are closed while others are open when said Split Scanning Circuit scans the electrodes with switches closed.

9. The method of claim 5, further comprising the steps of:

(c) outputting said raw coordinates as real coordinates of said multiple touch points when only one said centroid is computed in either said first direction or said second direction in said step (b).