METHOD OF DISTINGUISHING OBJECTS ON TOUCH PANEL BY REFERRING TO INDUCED CAPACITANCE SIGNAL DISTRIBUTIONS, AND RELATED COMPUTER READABLE MEDIUM THEREOF

• US 20120306806A1
• Filed: 05/14/2012
• Published: 12/06/2012
• Est. Priority Date: 05/30/2011
• Status: Active Grant

• Current Assignee: Elan Microelectronics Corporation
• Original Assignee: Elan Microelectronics Corporation
• Inventors: Yang, Tung-Ming, Mai, Wei-Kuo
• Granted Patent: US 9,207,816 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• 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 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• 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 of distinguishing a plurality of objects on a touch panel includes: scanning the touch panel to obtain a plurality of positions corresponding to the objects on the touch panel and a plurality of induced capacitance signals corresponding to the positions; identifying a plurality of maximum induced capacitance signals corresponding to the objects respectively; and distinguishing the objects by referring to induced capacitance signal distributions around the maximum induced capacitance signals.

Claims

1. A method of distinguishing a plurality of objects on a touch panel, comprising:

scanning the touch panel to obtain a plurality of positions corresponding to the objects on the touch panel and a plurality of induced capacitance signals corresponding to the positions;

identifying a plurality of maximum induced capacitance signals corresponding to the objects respectively; and

distinguishing the objects by referring to induced capacitance signal distributions around the maximum induced capacitance signals.

2. The method of claim 1, wherein the step of distinguishing the objects comprises:

regarding each of the objects;

on the touch panel, selecting a first induced capacitance signal around a maximum induced capacitance signal corresponding to the object or a first position corresponding to the first induced capacitance signal, and selecting a second induced capacitance signal around the maximum induced capacitance signal corresponding to the object or a second position corresponding to the second induced capacitance signal; and

differentiating the objects according to a plurality of first and second induced capacitance signals corresponding to the objects respectively, and a plurality of first and second positions corresponding to the first and second induced capacitance signals.

3. The method of claim 2, wherein the first induced capacitance signal is the maximum induced capacitance signal corresponding to the object.

4. The method of claim 2, wherein the first induced capacitance signal is the maximum induced capacitance signal corresponding to the object, and the second induced capacitance signal is a threshold value corresponding to the object.

5. The method of claim 4, wherein the threshold value is a predetermined proportion of the maximum induced capacitance signal corresponding to the object.

6. The method of claim 2, wherein the step of differentiating the objects comprises:

regarding each of the objects;

calculating a first difference between the first and the second induced capacitance signals corresponding to the object;

calculating a second difference between the first and the second positions corresponding to the object; and

calculating a ratio according to the first difference and the second difference; and

differentiating the objects according to ratios corresponding to the objects respectively.

7. The method of claim 2, wherein the step of differentiating the objects comprises:

regarding each of the objects;

calculating a first difference between the first and the second induced capacitance signals corresponding to the object;

calculating a second difference between the first and the second positions corresponding to the object; and

calculating an angle value according to the first difference and the second difference; and

differentiating the objects according to angle values corresponding to the objects respectively.

8. The method of claim 2, wherein the step of differentiating the objects comprises:

regarding each of the objects;

calculating a first difference between the first and the second induced capacitance signals corresponding to the object;

calculating a second difference between the first and the second positions corresponding to the object; and

calculating a trigonometric value according to the first difference and the second difference; and

differentiating the objects according to trigonometric values corresponding to the objects respectively.

9. The method of claim 2, wherein when the first induced capacitance signals corresponding to the objects respectively are equal to each other and the second induced capacitance signals corresponding to the objects respectively are equal to each other, the step of differentiating the objects comprises:

regarding each of the objects;

calculating a specific distance between the first and the second positions corresponding to the object; and

differentiating the objects according to calculated specific distances corresponding to the objects respectively.

10. The method of claim 2, wherein the step of selecting a first induced capacitance signal around a maximum induced capacitance signal corresponding to the object or a first position corresponding to the first induced capacitance signal, and selecting a second induced capacitance signal around the maximum induced capacitance signal corresponding to the object or a second position corresponding to the second induced capacitance signal comprises:

determining an induced range according to a threshold value, wherein induced capacitance signals corresponding to the object within the induced range are larger than or equal to the threshold value; and

selecting the first induced capacitance signal and the first position corresponding thereto, and the second induced capacitance signal and the second position corresponding thereto among the induced capacitance signals within the induced range.

11. The method of claim 10, wherein the step of selecting the first induced capacitance signal and the first position corresponding thereto, and the second induced capacitance signal and the second position corresponding thereto among the induced capacitance signals within the induced range comprises:

selecting the maximum induced capacitance signal as the first induced capacitance signal; and

selecting a position nearest to the first position as the second position among positions on a boundary of the induced range.

12. The method of claim 1, wherein the step of distinguishing the objects comprises:

determining an induced range on the touch panel according to a threshold value, wherein induced capacitance signals corresponding to the object within the induced range are larger than or equal to the threshold value; and

differentiating the objects according to the maximum induced capacitance signals corresponding to the objects, a plurality of threshold values, and areas of induced ranges corresponding to the objects.

13. The method of claim 12, wherein the threshold value is a predetermined proportion of the maximum induced capacitance signal corresponding to the object.

14. The method of claim 12, wherein the step of differentiating the objects comprises:

regarding each of the objects;

calculating a difference between the maximum induced capacitance signal and the threshold value corresponding to the object; and

calculating a ratio according to the difference and an area of the induced range corresponding to the object; and

differentiating the objects according to ratios corresponding to the objects respectively.

15. The method of claim 12, wherein the step of determining the induced range on the touch panel according to the threshold value comprises:

determining an area of a circle as the area of the induced range based on a radius which is a shortest distance between one of positions determined according to the threshold value and a position corresponding to the maximum induced capacitance signal.

16. The method of claim 1, wherein the maximum induced capacitance signals respectively corresponding to the objects have a same induced capacitance signal level, and the step of distinguishing the objects comprises:

regarding each of the objects;

determining an induced range according to a threshold value, wherein induced capacitance signals corresponding to the object within the induced range are larger than or equal to the threshold value; and

selecting a shortest distance between one of positions corresponding to a boundary of the induced range and a position corresponding to the maximum induced capacitance signal; and

differentiating the objects according to shortest distances found in the respective induced ranges corresponding to the objects respectively.

17. The method of claim 1, wherein the maximum induced capacitance signals respectively corresponding to the objects have a same induced capacitance signal level, and the step of distinguishing the objects comprises:

determining an induced range according to a threshold value, wherein induced capacitance signals corresponding to the object within the induced range are larger than or equal to the threshold value; and

differentiating the objects according to areas of induced ranges corresponding to the objects respectively.

18. A computer readable medium having a program code stored therein, wherein when executed by a processor, the program code causes the processor to execute following steps:

scanning the touch panel to obtain a plurality of positions corresponding to the objects on the touch panel and a plurality of induced capacitance signals corresponding to the positions;

identifying a plurality of maximum induced capacitance signals corresponding to the objects respectively; and

distinguishing the objects by referring to induced capacitance signal distributions around the maximum induced capacitance signals.