METHOD AND DEVICE FOR CAPACITIVE SENSING

• US 20100007629A1
• Filed: 07/09/2009
• Published: 01/14/2010
• 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
• Granted Patent: US 8,531,429 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 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

This invention discloses a capacitive sensing device. The device includes a plurality of first conductive lines electrically isolated from each other; a plurality of second conductive lines electrically isolated from each other and electrically isolated from and stacked with the first conductive lines to form a plurality of intersecting points; and a plurality of electrical conductors electrically isolated from each other and correspondingly crossing the first and the second conductive lines and being around the intersecting points, wherein the first and second conductive lines and the electrical conductors are electrically isolated from each other. By doing so, when an electrical signal is driven to any first conductive line, the first conductive line is capacitively coupled to the second conductive lines with which it intersects, and the electrical conductors crossing the first conductive line are respectively capacitively coupled to the first conductive line and the second conductive lines which intersect with the first conductive line to provide a higher compound capacitance.

Claims

1. A capacitive sensing device, comprising:

a sensing unit detecting changes in charge coupling between a plurality of first conductive lines, a plurality of second conductive lines and a plurality of electrical conductors around or overlaying the intersections of the first conductive lines and the second conductive lines; and

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

2. The capacitive sensing device of claim 1, wherein the first conductive lines and the second conductive lines are electrical isolated from and stacked on one another.

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 changes in charge coupling between the first conductive lines, the second conductive lines and the electrical conductors.

4. The capacitive sensing device of claim 3, wherein the position of each object is identified by an image formed from the changes in charge coupling between the first conductive lines, the second conductive lines and the electrical conductors.

5. The capacitive sensing device of claim 3, wherein the position of each object is identified according to multiple intersections.

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 the 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 conductive lines including a plurality of first conductive lines and a plurality of second conductive lines that are electrically isolated from each other and stacked on one another;

a plurality of electrical conductors around or overlaying the intersections of the conductive lines; and

a controller detecting the changes of mutual capacitances between the conductive lines and 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 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.

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

capacitively coupling each pair of intersecting conductive lines of a plurality of conductive lines by operatively driving one of the pair of intersecting conductive lines and sensing the other of the pair of intersecting conductive lines, wherein the intersection of each pair of intersecting conductive lines is around or overlaid by at least one electrical conductors separately; and

detecting the changes of mutual capacitances between the conductive lines and 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 14, wherein the threshold determines the positions of each pair of objects from four positions.

17. The method for controlling capacitive sensing device of claim 14, 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 each of the conductive lines is separately isolated.

19. The method for controlling capacitive sensing device of claim 14, wherein the position of each object is identified according an image formed from the changes of mutual capacitances between the conductive lines and the electrical conductors.

20. The method for controlling capacitive sensing device of claim 14, wherein the changes of mutual capacitances are detected by sensing the changes in charge coupling between the conductive lines and the electrical conductors.

21. 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 or contact coupled 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 second conductive lines when at least one of the electrical conductors capacitively or contact coupled with the object; and

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

wherein the electrical conductors respectively position around and cross intersecting points of the first conductive line and the second conductive lines, the first and second sensing signals respectively include compound values of capacitive coupling between the first conductive line, the second conductive lines and the electrical conductors before and after coupling.

22. The capacitive sensing device of claim 21, further comprising a plurality of the first conductive lines, the electrical signals being sequentially provided to one 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 an 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.

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

24. The capacitive sensing device of claim 21, 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.

25. 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 or contact coupled with an object, wherein the second conductive lines are electrically isolated from each other;

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

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

wherein the electrical conductors respectively position around and cross intersecting points of the first conductive line and the second conductive lines, the first and second sensing signals respectively include compound values of capacitive coupling between the first conductive line, the second conductive lines and the electrical conductors before and after coupling.

26. The capacitive sensing method of claim 25, wherein the first conductive line includes a plurality of the first conductive lines, the electrical signals being sequentially provided to one of the 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.

27. The capacitive sensing method of claim 25, 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.

28. The capacitive sensing method of claim 25, 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.

29. A capacitive sensing device, comprising:

a plurality of first conductive lines electrically isolated from each other;

a plurality of second conductive lines electrically isolated from each other, wherein the first and second conductive lines are electrically isolated from and stacked on one another forming a plurality of intersecting points;

a plurality of electrical conductors electrically isolated from each other, the electrical conductors respectively crossing the first and second conductive lines and positioning around the intersecting points, wherein the first and second conductive lines and the electrically conductors are electrically isolated from one another;

a signal unit for providing an electrical signal; and

a sensing unit for capacitively coupling with the signal unit through one of the first conductive lines, one of the second conductive lines and at least one of the electrical conductors, the at least one electrical conductor and the ones of first and second conductive lines being capacitively coupled, respectively, and wherein the one of the first conductive lines is driven by the electrical signal.

30. The capacitive sensing device of claim 29, wherein at least one intersecting point of the intersecting points has one or more of the electrically conductors at its surroundings and arranged in parallel, wherein the electrical conductors include a plurality of sub electrical conductors.

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

32. The capacitive sensing device of claim 29, wherein the sensing unit senses compound value of the capacitive coupling between the first and second conductive lines, the capacitive coupling between the first conductive lines and the electrical conductors and the capacitive coupling between the second conductive lines and the electrical conductors.

33. The capacitive sensing device of claim 29, 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.

34. The capacitive sensing device of claim 29, 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.

35. A capacitive sensing device, comprising:

a plurality of first conductive lines electrically isolated from each other;

a plurality of second conductive lines electrically isolated from each other, wherein the first and second conductive lines are electrically isolated from and stacked on one another forming a plurality of intersecting points; and

a plurality of electrical conductors electrically isolated from each other, the electrical conductors respectively crossing the first and second conductive lines and positioning around the intersecting points, wherein the first and second conductive lines and the electrically conductors are electrically isolated from one another; and

a sensing unit, when a plurality of objects capactively or contact coupled with at least one of the first and second conductive lines and the electrical conductors, the sensing unit sensing a compound value of the capacitive couplings between the objects and the coupled first and second conductive lines and electrical conductors, providing a higher difference for identifying and eliminating ghost coordinates that are coupled with the objects.

36. A capacitive sensing device comprising a plurality of first and second conductive lines forming a plurality of intersecting points and detecting at least one touched location based on mutual-capacitance of the intersecting points, 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, characterized in that the capacitive sensing device further comprising:

a plurality of electrical conductors crossing the intersecting points, the dimension of the electrical conductors determining signal differences between the intersecting points around the real vertices and those around the pseudo vertices.

37. The capacitive sensing device of claim 36, further comprising a sensing unit for sensing compound signals of the intersecting points that are affected by the capacitive couplings of the electrical conductors, wherein each electrical conductor crosses one of the intersecting points, and the compound signal of each intersecting point is a capacitive coupling signal between the first and second conductive lines crossed by each electrical conductor.

38. The capacitive sensing device of claim 37, 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.