Method and apparatus for sensing multi-touch inputs

• US 8,830,185 B2
• Filed: 11/22/2010
• Issued: 09/09/2014
• Est. Priority Date: 05/22/2008
• Status: Expired due to Fees

• Current Assignee: Melfas Incorporated
• Original Assignee: Melfas Incorporated
• Inventors: Ryu, Siwon, Ji, Sangwon
• Primary Examiner(s): DINH, DUC Q
• Application Number:
  US12/926,482
• Publication Number:
  US 20110069029A1
• Time in Patent Office: 1,387 Days
• Field of Search: 345/156, 345173-181
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• 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 method for sensing two or more touch inputs includes receiving sensing signals of the touch inputs from plural sensing electrodes, calculating a value dependent on a distance between the touch inputs based on the received sensing signals, and determining the existence of the two or more touch inputs if the calculated value is more than or equal to a threshold value. The plural sensor electrodes include a pair of sensing electrodes that correspond to same coordinates on a first axis, and the sensing signals are received from the pair of sending electrodes along the first axis.

Claims

1. A method for sensing two or more touch inputs, the method comprising:

receiving sensing signals of the touch inputs from plural sensing electrodes;

calculating a value dependent on a distance between the touch inputs based on the received sensing signals by;

a. calculating a standard deviation from the sensing signals, and

b. obtaining said value dependent on the distance by mapping a standard deviation to a corresponding said distance using a mapping table created in advance; and

determining the existence of the two or more touch inputs if the calculated value is more than or equal to a threshold value,

wherein a distance between the plural sensing electrodes is adjustable.

2. The method of claim 1, wherein said calculating a value dependent on a distance between the touch inputs includes calculating the distance-dependent value based on a distribution of intensities of the sensing signals along a first axis.

3. The method of claim 1, wherein said calculating a value dependent on a distance between the touch inputs includes calculating the distance-dependent value based on a distribution of intensities of the sensing signals along at least one of a first and second axes not parallel to each other.

4. The method of claim 1, further comprising:

if it is determined that there exist the two or more touch inputs, calculating a position of a center point between the two or more touch inputs; and

determining positions of the touch inputs based on the position of the center point and the distance-dependent value between the touch inputs.

5. The method of claim 1, further comprising:

if it is determined that there exist the two or more touch inputs, calculating a position of a reference point between the two or more touch inputs; and

dividing the sensing signals into plural sensing signal groups with reference to the reference point and calculating positions of the touch points from the each divided sensing signal groups.

6. The method of claim 5, wherein said calculating the position of the reference point includes calculating, as the reference point, a point at which intensities of the sensing signals have a minimum value.

7. The method of claim 5, wherein said calculating the positions of the touch points includes calculating a weighted mean with regard to at least one axis using the sensing signals as weighted values.

8. The method of claim 5, wherein said calculating the positions of the touch points includes calculating a ratio of the sensing signals of adjacent sensing electrodes on at least one axis.

14. A touch detection apparatus for sensing touch inputs using the method of claim 1.

9. A method for sensing two or more touch inputs, the method comprising:

receiving sensing signals through plural sensing electrodes;

calculating a value dependent on a distance between the touch inputs based on the received sensing signals by;

a. calculating a standard deviation from the sensing signals, and

b. obtaining said value dependent on the distance by mapping a standard deviation to a corresponding said distance using a mapping table created in advance;

determining the existence of the two or more touch inputs if the calculated value is more than or equal to a threshold value;

dividing the sensing signals into plural sensing signal groups when the existence of the two or more touch inputs is determined; and

calculating a position of at least one touch input from at least one of the divided sensing signal groups,

wherein a distance between the plural sensing electrodes is adjustable.

10. The method of claim 9, wherein said dividing the sensing signals includes dividing the sensing signals about a point at which intensities of the sensing signal have a minimum value.

11. The method of claim 9, wherein said dividing the sensing signals includes:

determining a center point of the two or more touch inputs; and

dividing the sensing signals with reference to the center point.

12. The method of claim 9, wherein said calculating the position of at least one touch point includes calculating a weighted mean with respect to at least one axis using the sensing signals as weighted values.

13. The method of claim 9, wherein said calculating the position of at least one touch point includes calculating a ratio of the sensing signals between adjacent sensing electrodes with respect to at least one axis.