Signal transfer method and apparatus

• US 20050174259A1
• Filed: 06/05/2003
• Published: 08/11/2005
• Est. Priority Date: 06/05/2002
• Status: Active Grant

• Current Assignee: Synaptics (UK) Ltd. (Synaptics Incorporated)
• Original Assignee: Synaptics (UK) Ltd. (Synaptics Incorporated)
• Inventors: Ely, David Thomas Eliot
• Granted Patent: US 7,907,130 B2
• Time in Patent Office: Days
• US Class Current: 341/5
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

An x-y digitising system is described which operates with a resonant stylus. The x-y digitising system includes an excitation winding for energising the resonant stylus and a number of sensor windings for receiving a signal re-radiated by the resonant stylus when energised. At least one of the excitation winding and the sensor winding is arranged to have its effective magnetic axis non-othogonal to the working area of the x-y digitising system. With this arrangement, improved energy transfer between the x-y digitising system and the resonant stylus can be achieved and/or improved position measurement accuracy can be obtained.

Claims

1. A signal transferring apparatus comprising:

first and second members which are relatively movable over an x-y planar working area;

the first member comprising a coil whose effective magnetic axis is non-orthogonal to the x-y planar working area; and

the second member comprising an electromagnetic device operable to interact with said coil to exchange a signal between said first and second members.

2. An apparatus according to claim 1, wherein said first member further comprises a drive circuit operable to apply a drive signal to said coil to create a magnetic field over said x-y planar working area and wherein said electromagnetic device of said second member is operable to be energised by said magnetic field.

3. An apparatus according to claim 2, wherein said electromagnetic device comprises a coil which is operable to couple with said magnetic field to energise said electromagnetic device.

4. An apparatus according to claim 2, wherein said electromagnetic device comprises a resonator.

5. An apparatus according to claim 1, wherein said electromagnetic device is operable to generate an electromagnetic field which interacts with said coil to generate one or more sensor signals and wherein said first member further comprises a processor operable to process said one or more sensor signals.

6. An apparatus according to claim 5, wherein said one or more sensor signals vary with the status of said electromagnetic device and wherein said processor is operable to process said one or more sensor signals to determine the current status of the electromagnetic device.

7. An apparatus according to claim 6, wherein said status comprises the current position of the second member relative to the first member and wherein said processor is operable to process said one or more sensor signals to determine the current position of said second member relative to said first member.

8. An apparatus according to claim 5, wherein said one or more sensor signals are generated in said coil.

9. An apparatus according to claim 5, wherein said first member comprises one or more additional coils and wherein said one or more sensor signals are generated in said one or more additional coils.

10. An apparatus according to claim 9, wherein said one or more additional coils are formed as conductor tracks on a printed circuit board.

11. An apparatus according to claim 10, wherein said circuit board lies predominately within a plane parallel to said planar working area and comprises foldable portions which, in use, lie at an angle to said plane and wherein one or more loops of at least one of said additional coils are formed on said foldable portions.

12. An apparatus according to claim 11, wherein said foldable portions are at an edge of said circuit board.

13. An apparatus according to claim 11, wherein said circuit board comprises a transparent window.

14. An apparatus according to claim 13, wherein said first member comprises a display and wherein said circuit board is arranged to fit over or under said display and wherein said foldable portions fold along the sides of the display.

15. An apparatus according to claim 1, wherein said first member comprises a plurality of coils whose effective magnetic axes are non-orthogonal to the x-y planar working area.

16. An apparatus according to claim 1, wherein the effective magnetic axis of said winding lies at an angle of between zero and 60E to the plane of said x-y planar working area.

17. An apparatus according to claim 1, wherein the effective magnetic axis of said coil is substantially parallel to the x-y planar working area.

18. An apparatus according to claim 1, wherein said first member comprises one or more additional coils whose effective magnetic axes is substantially orthogonal to the x-y planar working area.

19. An apparatus according to claim 18, wherein said one or more additional coils are formed over a peripheral portion of said x-y planar working area.

20. An apparatus according to claim 18, wherein said one or more additional coils are arranged to have a sensitivity function to magnetic field which spatially varies approximately sinusoidally across at least one dimension of said x-y planar working area.

21. An apparatus according to claim 1, wherein said coil comprises first and second coil portions which are located on opposite edges of the x-y planar working area and which are connected in series to have a sensitivity function which spatially varies approximately sinusoidally across the planar working area.

22. An apparatus according to claim 1, wherein said first member includes an x-y circuit board arranged substantially parallel to said x-y planar working area and wherein said coil is wound around at least a part of said planar circuit board so that its effective magnetic axis substantially lies in a plane parallel to said working area.

23. An apparatus according to claim 1, wherein said first member comprises a layer of high magnetic permeability material arranged substantially parallel to said x-y planar working area, and wherein said coil is wound around at least a part of said magnetic material such that its effective magnetic axis substantially lies in a plane parallel to said working area.

34. A method of transferring signals comprising the step of using an apparatus according to claim 1.

24. An x-y position sensor comprising:

first and second members which are relatively movable over an x-y planar working area;

the first member comprising a coil whose effective magnetic axis is non-orthogonal to the x-y planar working area;

the second member comprising an electromagnetic device operable to interact with said coil to transfer a signal between said first and second members, which signal varies with the relative position of the first and second members; and

a processor operable to process said signal to determine the relative position of the first and second members.

25. A portable computing device comprising:

a planar display;

an x-y digitiser associated with the display and operable to sense the status of an indicator which is moveable relative to the display; and

a processor operable to control the display in accordance with the sensed status of said moveable indicator; and

wherein said x-y digitiser comprises at least one winding whose effective magnetic axis is non-orthogonal to the plane of said display.

26. An x-y position sensor comprising:

first and second members which are relatively movable over an x-y planar working area;

the first member comprising a plurality of windings arrayed over the x-y planar working area and each winding comprising at least two loops wound in opposite senses;

the second member comprising an electromagnetic device operable to interact with said plurality of windings to generate signals that vary with the relative x-y position of the first and second members; and

wherein the loops of said plurality of windings are arranged in at least two rows and at least two columns, with loops in the same column being wound in the same sense and with adjacent loops in the same row being wound in alternating sense.

27. A sensor according to claim 26, wherein the loops of each winding are positioned diagonally within said rows and columns.

28. A sensor according to claim 26, wherein each winding includes at least one loop in each row and at least one loop in each column.

29. A sensor according to claim 28, wherein the loops of each winding are located in alternating positions of said rows and columns.

30. A planar circuit board for use in an x-y position sensor, the circuit board comprising:

a plurality of windings arrayed over the board, each winding comprising at least two loops wound in opposite senses and wherein the loops of said plurality of windings are arranged in at least two rows and at least two columns, with loops in the same column being wound in the same sense and with adjacent loops in the same row being wound in alternating sense.

31. A circuit board for use in a position sensor, the circuit board comprising:

a central portion having one or more conductor loops and a flexible peripheral portion which has one or more conductor loops and which can flex relative to said central portion.

32. A circuit board according to claim 31, wherein said central portion includes a transparent window and wherein said conductor loops of said central portion are formed at at least one edge of said transparent window.

33. A circuit board according to claim 32, adapted to fit over a display, with the display being viewable through said transparent window and said flexible portion being arranged to fit over the sides of said display.

35. An x-y position sensor comprising:

first and second members which are relatively movable over an x-y planar working area;

the first member comprising a plurality of windings arrayed over the x-y planar working area and each winding comprising at least two loops wound in the opposite sense;

the second member comprising an electromagnetic device operable to interact with said plurality of windings to generate signals that vary with the relative x-y position of the first and second member; and

wherein the electromagnetic coupling between said electromagnetic device and at least one of said windings varies with both the relative position of said first and second members in both the x and y directions.

36. An x-y position sensor comprising:

first and second members which are relatively movable over an x-y planar working area;

the first member comprising a circuit board arranged substantially parallel to said planar working area and comprising at least one winding arranged in a x direction and at least one winding arranged in a y direction;

the second member comprising an electromagnetic device operable to interact with said windings to generate signals that vary with the relative x-y position of the first and second members; and

wherein said windings are arranged on a peripheral edge of said circuit board and wherein a central portion of said circuit board is free of windings.

37. A sensor according to claim 36, wherein said central portion of said circuit board includes a transparent window.

38. A portable computing device comprising:

a display;

a x-y digitiser associated with the display and operable to sense the status of an indicator which is movable relative to the display; and

a processor operable to control the display in accordance with the sensed status of said movable indicator; and

wherein said x-y digitiser comprises at least one winding whose effective magnetic axes is non orthogonal to the plane of said display and is operable to power said indicator when operating above the display and when operating to a side of the portable computing device.

39. A device according to claim 38, wherein said indicator has a first mode of operation in which the indicator interacts with said x-y digitiser and a second mode of operation in which it acts as a conventional mouse and is powered by said at least one winding of said x-y digitiser.