Method and device for capacitive sensing

• US 8,531,429 B2
• Filed: 07/09/2009
• Issued: 09/10/2013
• Est. Priority Date: 07/09/2008
• Status: Active Grant

• Current Assignee: eGalax_eMPIA Technology Inc.
• Original Assignee: eGalax_eMPIA Technology Inc.
• Inventors: Chang, Chin-Fu
• Primary Examiner(s): Zhou, Hong
• Application Number:
  US12/499,965
• Publication Number:
  US 20100007629A1
• Time in Patent Office: 1,524 Days
• Field of Search: 345173-174, 178/18.01, 178/18.06
• 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 2203/04808 Several contacts: gestures triggering a specific function, e.g. scrolling, zooming, right-click, when the user establishes several contacts with the surface simultaneously; e.g. using several fingers or a combination of fingers and pen
• 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
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text

Abstract

The disclosed capacitive sensing device has first conductive lines, second conductive lines and electrical conductors. The first conductive lines are electrically isolated from each other, the second conductive lines are electrically isolated from each other and electrically isolated from and stacked with the first conductive lines to form numerous intersecting points, and the electrical conductors are electrically isolated from each other and correspondingly crossing the first and the second conductive lines and being around the intersecting points. Herein, the electrical conductors are electrically isolated from the first and second conductive lines. When an electrical signal is driven to a first conductive line, the first conductive line is capacitively coupled to the second conductive lines which intersecting mutually, and the electrical conductors crossing the first conductive line are respectively capacitively coupled to the first conductive line and the mutually intersecting second conductive lines to provide a higher compound capacitance.

Claims

1. A capacitive sensing device, comprising:

a sensing unit detecting three mutual capacitance changes in charge coupling, wherein the three mutual capacitance changes include a first mutual capacitance change between one of a plurality of first conductive lines and one of a plurality of second conductive lines, a second mutual capacitance change between at least one of a plurality of electrical conductors and the one of the plurality of first conductive lines, and a third mutual capacitance change between the at least one of the plurality of electrical conductors and the one of the plurality of second conductive lines;

a signal unit operatively driving an electrical signal to capacitively couple with the sensing unit through the one of the first conductive lines, the one of the second conductive lines and the one of the electrical conductors;

wherein the plurality of first conductive lines are oriented in a first direction and the plurality of second conductive lines are oriented in a second direction;

wherein the plurality of first conductive lines and the plurality of second conductive lines are electrically isolated from each other and intersecting with each other to form a plurality of intersecting points;

wherein at least one of the plurality of electrical conductors overlays each of the plurality of intersecting points.

2. The capacitive sensing device of claim 1, wherein the plurality of first conductive lines are on a first layer and the plurality of electrical conductors are on a second layer, wherein the second layer is above the first layer.

3. The capacitive sensing device of claim 1, comprising:

a position identifying unit identifying a position of each object touching or being near the capacitive sensing device by the three mutual capacitance changes in charge coupling.

4. The capacitive sensing device of claim 3, wherein the position of each object is identified by an image formed from the three mutual capacitance changes in charge coupling.

5. The capacitive sensing device of claim 3, wherein the position of each object is identified according to the plurality of intersecting points.

6. The capacitive sensing device of claim 3, wherein the position identifying unit identifying the position of each object according to a threshold determined by the dimension of the electrical conductors.

7. The capacitive sensing device of claim 6, wherein the threshold determines the positions of each pair of objects from four positions.

8. The capacitive sensing device of claim 7, wherein the threshold determines the positions of each pair of objects from four positions according to the three mutual capacitance changes in charge coupling between the intersections near two pairs of diagonal within a virtual bounding parallelogram, wherein the threshold determines the position of each pair of objects according the changes in charge coupling between the intersections near one pair of diagonal within the virtual bounding parallelogram.

9. A capacitive sensing device, comprising:

a plurality of first conductive lines oriented in a first direction and a plurality of second conductive lines oriented in a second direction, wherein the plurality of first conductive lines and the plurality of second conductive lines electrically isolated from each other and intersecting with each other to form a plurality of intersecting points;

a plurality of electrical conductors, wherein at least one of the plurality of electrical conductors overlays each of the plurality of intersecting points; and

a controller detecting the three mutual capacitance changes including;

a first mutual capacitance change between one of the plurality of first conductive lines and one of the plurality of second conductive lines, a second mutual capacitance change between the one of the plurality of first conductive lines and at least one of the electrical conductors, the third mutual capacitance change between the one of the second conductive lines and the at least one of the electrical conductors.

10. The capacitive sensing device of claim 9, wherein the controller capacitively coupling two intersecting conductive lines by operatively driving one of the two intersecting conductive lines and sensing the other of the two intersecting conductive lines.

11. The capacitive sensing device of claim 9, wherein the controller identifies a position of each object touching or being near the conductive lines according to a threshold determined by the dimension of the electrical conductors.

12. The capacitive sensing device of claim 11, wherein the threshold determines the positions of each pair of objects from four positions.

13. The capacitive sensing device of claim 11, wherein the threshold determines the positions of each pair of objects from four positions according to the three mutual capacitance changes between the intersections near two pairs of diagonals within a virtual bounding parallelogram, wherein the threshold determines the position of each pair of objects according to the three mutual capacitance changes between the intersections near one pair of diagonal within the virtual bounding parallelogram.

14. A method for controlling capacitive sensing device, comprising:

providing a pair of conductive lines comprising a first conductive line oriented in a first direction and a second conductive line oriented in a second direction, wherein the first conductive line and the second conductive line are electrically isolated from each other and intersecting with each other to form an intersecting point;

providing at least one electrical conductors wherein the at least one electrical conductors overlays the intersecting point;

capacitively coupling the pair of conductive lines by operatively driving one of the pair of conductive lines and sensing the other of the pair of conductive lines; and

detecting the three mutual capacitance changes including a first mutual capacitance change between the first conductive line and the second conductive line, a second mutual capacitance change between the first conductive line and the at least one electrical conductors, and a third mutual capacitance change between the second conductive line and the at least one electrical conductors.

15. The method for controlling capacitive sensing device of claim 14, further comprising:

identifying a position of each object touching or being near the electrical conductors according to a threshold determined by the dimension of the electrical conductors.

16. The method for controlling capacitive sensing device of claim 15, wherein the threshold determines the positions of each pair of objects from four positions.

17. The method for controlling capacitive sensing device of claim 15, wherein the threshold determines the positions of each pair of objects from four positions according the changes of mutual capacitances between the intersections near two pairs of diagonals within a virtual bounding parallelogram, wherein the threshold determines the position of each pair of objects according the changes of mutual capacitances between the intersections near one pair of diagonal within the virtual bounding parallelogram.

18. The method for controlling capacitive sensing device of claim 14, wherein the position of each object is identified according to an image formed from the three mutual capacitance changes.

19. A capacitive sensing device, comprising:

a signal unit for providing an electrical signal to a first conductive line;

a first sensing unit for respectively receiving a plurality of first sensing signals from a plurality of second conductive lines before at least one of a plurality of electrical conductors capacitively couple with an object, wherein the second conductive lines are electrically isolated from each other;

a second sensing unit for respectively receiving a plurality of second sensing signals from the plurality of second conductive lines when the at least one of the electrical conductors capacitively couple with the object; and

a calculation unit for calculating at least one touched location based on the first and second sensing signals,

wherein the first conductive line is oriented in a first direction and the second conductive lines are oriented in a second direction, the first conductive line and the plurality of second conductive lines are electrically isolated from and intersecting with each other to form a plurality of intersecting points;

wherein the at least one of the plurality of electrical conductors overlays each of the plurality of intersecting points;

wherein the first and second sensing signals respectively include three mutual capacitance changes before and after coupling; and

wherein the three mutual capacitance changes include a first mutual capacitance change between the first conductive line and one of a plurality of second conductive lines, a second mutual capacitance change between the at least one of a plurality of electrical conductors and the first conductive line, and a third mutual capacitance change between the at least one of the plurality of electrical conductors and the one of the plurality of second conductive lines.

20. The capacitive sensing device of claim 19, further comprising a plurality of the first conductive lines, the electrical signals being sequentially provided to each of the first conductive lines, wherein the first and second conductive lines perpendicularly intersect one another, wherein the at least one touched location includes a location around the intersecting point, wherein the calculation unit includes calculating the pressure of the at least one touched location based on the first and second sensing signals.

21. The capacitive sensing device of claim 19, wherein the calculation unit calculates the at least one touched location by obtaining capacitance images according to the first and second sensing signals, respectively.

22. The capacitive sensing device of claim 19, wherein any two touched locations constitute a pair of diagonal real vertices on a virtual bounding parallelogram, and the dimension of the electrical conductors determines signal differences between intersecting points around the real vertices and another pair of pseudo vertices on the virtual bounding parallelogram.

23. A capacitive sensing method, comprising:

providing an electrical signal to a first conductive line;

receiving a plurality of first sensing signals from a plurality of second conductive lines before at least one of a plurality of electrical conductors capacitively couple with an object, wherein the second conductive lines are electrically isolated from each other;

receiving a plurality of second sensing signals from the plurality of second conductive lines when the at least one of the electrical conductors capacitively couple with the object; and

calculating at least one touched location based on the first and second sensing signals,

wherein the first conductive line is oriented in a first direction and the second conductive lines are oriented in a second direction, the first conductive line and the plurality of second conductive lines are electrically isolated from and intersecting with each other to form a plurality of intersecting points;

wherein the at least one of the plurality of electrical conductors overlays each of the plurality of intersecting points;

wherein the first and second sensing signals respectively include three mutual capacitance changes before and after coupling; and

wherein the three mutual capacitance changes include a first mutual capacitance change between the first conductive line and one of a plurality of second conductive lines, a second mutual capacitance change between the at least one of a plurality of electrical conductors and the first conductive line, and a third mutual capacitance change between the at least one of the plurality of electrical conductors and the one of the plurality of second conductive lines.

24. The capacitive sensing method of claim 23, wherein a plurality of electrical signals are sequentially provided to each of a plurality of first conductive lines, wherein the first and second conductive lines perpendicularly intersect one another, and the at least one touched location includes a location around an intersecting point, wherein calculating at least one touched location based on the first and second sensing signals includes calculating the pressure of the at least one touched location based on the first and second sensing signals.

25. The capacitive sensing method of claim 23, wherein calculating at least one touched location based on the first and second sensing signals includes calculating the at least one touched location by obtaining capacitance images according to the first and second sensing signals, respectively.

26. The capacitive sensing method of claim 23, wherein any two touched locations constitute a pair of diagonal real vertices on a virtual bounding parallelogram, and the dimension of the electrical conductors determines signal differences between intersecting points around the real vertices and another pair of pseudo vertices on the virtual bounding parallelogram.

27. A capacitive sensing device, comprising:

a plurality of first conductive lines oriented in a first direction and electrically isolated from each other;

a plurality of second conductive lines oriented in a second direction and electrically isolated from each other, wherein the plurality of first conductive lines and the plurality of second conductive lines are electrically isolated from and intersecting with each other to form a plurality of intersecting points;

a plurality of electrical conductors, wherein at least one of the plurality of electrical conductors overlays each of the plurality of intersecting points;

a signal unit for providing an electrical signal, wherein the one of the plurality of first conductive lines is driven by the electrical signal; and

a sensing unit for capacitively coupling with the signal unit through one of the plurality of first conductive lines, one of the plurality of second conductive lines and at least one of the plurality of electrical conductors;

wherein the sensing unit detects three mutual capacitance changes in charge coupling, and the three mutual capacitance changes include a first mutual capacitance change between one of a plurality of first conductive lines and one of a plurality of second conductive lines, a second mutual capacitance change between at least one of a plurality of electrical conductors and the one of the plurality of first conductive lines, and a third mutual capacitance change between the at least one of the plurality of electrical conductors and the one of the plurality of second conductive lines.

28. The capacitive sensing device of claim 27, wherein at least one intersecting point of the intersecting points are being overlaid by one or more of the electrical conductors, wherein the electrical conductors are arranged in parallel and include a plurality of sub electrical conductors.

29. The capacitive sensing device of claim 27, wherein the signal unit sequentially drives the electrical signal to each of the first conductive lines.

30. The capacitive sensing device of claim 27, wherein sensing of the sensing unit includes sensing the capacitive coupling of at least one of the intersecting points and at least one capacitive coupling between the intersecting points, so as to calculate at least one coordinate location and at least one location between a plurality of coordinates.

31. The capacitive sensing device of claim 27, wherein any two touched locations constitute a pair of diagonal real vertices on a virtual bounding parallelogram, and the dimension of the electrical conductors determines signal differences between intersecting points around the real vertices and another pair of pseudo vertices on the virtual bounding parallelogram.

32. A capacitive sensing device, comprising:

a plurality of first conductive lines oriented in a first direction and electrically isolated from each other;

a plurality of second conductive lines oriented in a second direction and electrically isolated from each other, wherein the first and second conductive lines are electrically isolated from and intersecting with each other to form a plurality of intersecting points; and

a plurality of electrical conductors electrically isolated from each other, wherein at least one electrical conductors overlays each of the plurality of intersecting points; and

a sensing unit, when a plurality of objects capactively couple with at least one of the first and second conductive lines and the electrical conductors, the sensing unit sensing three mutual capacitance changes, providing an amplified difference for identifying and eliminating ghost coordinates that are coupled with the objects

wherein the three mutual capacitance changes include a first mutual capacitance change between one of a plurality of first conductive lines and one of a plurality of second conductive lines, a second mutual capacitance change between at least one of a plurality of electrical conductors and the one of the plurality of first conductive lines, and a third mutual capacitance change between the at least one of the plurality of electrical conductors and the one of the plurality of second conductive lines.

33. A capacitive sensing device comprising a plurality of first and second conductive lines forming a plurality of intersecting points and a plurality of electrical conductors overlaying the intersecting points;

wherein said capacitive sensing device detects at least one touched location based on at least one compound capacitive coupling value of the intersecting points, wherein each compound capacitive coupling value includes three mutual capacitance changes;

wherein the three mutual capacitance changes include a first mutual capacitance change between one of a plurality of first conductive lines and one of a plurality of second conductive lines, a second mutual capacitance change between one of a plurality of electrical conductors and the one of the plurality of first conductive lines, and a third mutual capacitance change between the one of the plurality of electrical conductors and the one of the plurality of second conductive lines;

wherein any two touched locations constitute a pair of diagonal real vertices on a virtual bounding parallelogram, the other pair of diagonal on the virtual bounding parallelogram being a pair of pseudo vertices;

wherein the dimension of the electrical conductors determines signal differences between the intersecting points around the real vertices and those around the pseudo vertices.

34. The capacitive sensing device of claim 33, further comprising a sensing unit for sensing the at least one compound capacitive coupling value of the intersecting points.

35. The capacitive sensing device of claim 34, further comprising a calculation unit for distinguishing at least one group of neighboring intersecting points based on the intensity between the amounts of changes in the compound signals, each group of intersecting points corresponding to one of the at least one touched location.