Position detecting device

• US 4,988,837 A
• Filed: 04/30/1990
• Issued: 01/29/1991
• Est. Priority Date: 12/25/1987
• Status: Expired due to Term

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Wacom Co Limited (Wacom)
• Inventors: Aoki, Kazuo, Abe, Manabu, Siguyama, Keiichi, Kikuchi, Akio, Murakami, Azuma, Senda, Toshiaki, Funahashi, Takahiko, Yamanami, Tsuguya, Miyamori, Nobuyuki
• Primary Examiner(s): SCHREYER, STAFFORD
• Application Number:
  US07/516,866
• Time in Patent Office: 274 Days
• Field of Search: 178/18, 178/19, 340/706, 340/784
• US Class Current: 178/18.07
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

The position on a surface of an implement including a tuned circuit with a predetermined resonant frequency is determined and displayed by an apparatus having a housing including the surface. A tablet in the housing includes coils arranged in two coordinate directions parallel to the surface. The coils are excited with AC energy having approximately the same frequency as the resonant frequency. The tuned circuit interacts with the AC energy to change the AC current flowing in the coils as a function of the implement on the tablet. An electronic two-coordinate direction display in the housing configured as a plate is superposed with and lies in a plane parallel to the tablet and the surface. The display responds to the change in AC current resulting from the interaction between the AC energy and the tuned circuit to indicate the position of the implement on the surface.

Claims

1. A position detecting device having:

a position pointer having a tuning circuit; and

a tablet for position detection having electric wave generating means for generating an electric wave at a frequency equal to the resonance frequency of said tuning circuit, and electric wave detecting means for detecting an electric wave reflected by said tuning circuit,

coordinate values of a position designated with said position pointer on said tablet being detected by exchange of electric waves between said position pointer and said tablet,

said position detecting device comprising;

coordinate display means for displaying said designated position with coordinates corresponding to said coordinate values; and

a back light for illuminating said display means from below.

2. A position detecting device according to claim 1, wherein said back light is constituted by an electroluminescent element.

3. A position detecting device according to claim 1, wherein said back light is a cold cathode lamp.

4. A position detecting device comprising:

a section for detecting a position in X- and Y-directions having on its transparent base a group of a plurality of transparent loop coils arranged in X-direction and a group of a plurality of transparent loop coils arranged in Y-direction;

An X/Y-direction selection circuit for selecting said X-direction loop coils one after another and also selecting said Y-direction loop coils one after another;

a transmission circuit generating an alternating signal of a predetermined frequency to be supplied to said X-direction and Y-direction loop coils.

a receiving circuit for detecting an induced voltage of a frequency substantially equal to that of said alternating signal from induced voltages generating across said X-direction and Y-direction loop coils;

an X/Y direction connection change-over circuit for connecting one of each of said group of X-direction and Y-direction loop coils alternately to said transmission circuit and said receiving circuit;

a position pointer having a tuning circuit including a coil and a capacitor, said tuning circuit being capable of tuning with an electric wave generating from said X-direction and Y-direction loop coils to which said alternating signal is supplied;

a processor for obtaining a position designated with said position pointer in X- and Y-directions from induced voltages generating across said X-direction and Y-direction loop coils; and

coordinate display means making use of said base in common as a cover plate, said coordinate display means displaying X-direction and Y-direction data on said designated position as coordinates corresponding to the coordinates of said designated position.

5. A position detecting device according to claim 4, wherein said tuning circuit of said position pointer is capable of varying phases of voltages and current by the operation of a switch means, and the state of said switch means in said position pointer is detected from the phase of an induced voltage detected in said receiving circuit.

6. A position detecting device having:

a sensing section having light-transmission properties;

a position pointer for designating a position; and

a position detection control circuit for obtaining coordinate values of a position designated with said position pointer,

said position detection device comprising display means for displaying positional data obtained in said position detection control circuit as coordinates corresponding to the coordinates of said designated position, said display means being superposed over said sensing section, said display means having a back light disposed below said display means to illuminate the same from below, thus constituting a tablet.

67. A position detecting device according to claim 6 wherein said back light is constituted by a cold cathode lamp.

7. A position detecting device having:

a sensing section having an X-direction loop coil assembly formed of a multiplicity of loop coils arranged in X-direction, a Y-direction loop coil assembly formed of a multiplicity of loop coils arranged in Y-direction, and a transparent base for retaining said loop coil assemblies in predetermined positions;

a position pointer having a tuning circuit having a predetermined tuning frequency, said tuning circuit including at least a coil and a capacitor;

and a position detection control circuit having X-direction selection means for selecting said loop coils in said X-direction loop coil assembly one after another, Y-direction selection means for selecting said loop coils in said Y-direction loop coil assembly one after another, signal generating means for generating an alternating signal of said predetermined frequency, signal detecting means for detecting said alternating signal of said predetermined frequency, connection change-over means for alternately connecting said signal generating means and said signal detecting means successively to said X-direction and Y-direction loop coils selected by said selection means, and coordinate detecting means for obtaining X-direction and Y-direction coordinate values of a position designated with said position pointer on the basis of alternating signals detected from said X-direction and Y-direction loop coils detected by said signal detecting means,

said position detecting device comprising display means for displaying positional data obtained in said position detection control circuit as coordinates corresponding to the coordinates of said designated position, said display means being superposed over said sensing section, said display means having a back light disposed below said display means to illuminate the same from below, thus constituting a tablet.

68. A position detecting device according to claim 7 wherein said back light is constituted by a cold cathode lamp.

8. A position detecting device having a sensing section composed of an X-direction loop coil assembly formed of a multiplicity of loop coils arranged in X-direction and a Y-direction loop coil assembly formed of a multiplicity of loop coils arranged in Y-direction, a position pointer having a tuning circuit including at least a coil and a capacitor, and a position detection control circuit which selects said X-direction loop coils and said Y-direction loop coils one after another, intermittently supplies an alternating signal to the coil thereby selected, and obtains X-direction and Y-direction coordinate values of a designated position on the basis of relative receiving levels of said loop coils determined after each of said loop coils has received, during the suspension period of said intermittent supply, an alternating signal transmitted from said position pointer by tuning to said alternating signal intermittently supplied,

said position detecting device comprising display unit constituted by coordinate display means for displaying X-direction and Y-direction data on said designated position as coordinates corresponding to the coordinates of said designated position, and a back light disposed below said display means to illuminate the same from below, said display unit being superposed over said sensing section to form a tablet together with said sensing section.

9. Apparatus for determining and displaying the position of an implement on a surface, the implement including a tuned circuit with a predetermined resonant frequency, the apparatus comprising

a housing including the surface,

a tablet in the housing including coils arranged in two coordinate directions parallel to the surface,

means for exciting the coils with AC energy having approximately the same frequency as the resonant frequency, the tuned circuit interacting with the AC energy to change the AC current flowing in the coils as a function of the implement position on the tablet,

an electronic two-coordinate direction display in the housing configured as a plate superposed with and lying in a plane parallel to the tablet and the surface responsive to the change in AC current resulting from the interaction between the AC energy and the tuned circuit for indicating the position of the implement on the surface.

10. The apparatus of claim 9 further including means for detecting the amplitude of the current flowing in the coils as a result of the interaction between the AC energy and the tuned circuit, the detected amplitude controlling the indication position of the implement.

11. The apparatus of claim 10 further including means for detecting the phase of the current flowing in the coils.

12. The apparatus of claim 9 wherein the surface is an exterior surface of the housing, the display including the surface.

13. The apparatus of claim 12 further including a planar light emitting surface in the housing superposed with the surface, display and tablet.

14. The apparatus of claim 13 wherein the light emitting surface comprises a light reflecting surface.

15. The apparatus of claim 14 wherein the electronic display is substantially transparent to and is positioned to be responsive to ambient light, the light emitting surface consisting of the light reflecting surface, the light-reflecting surface being positioned to reflect the ambient light transmitted through the display back to and through the display.

16. The apparatus of claim 15 wherein the light reflecting surface is positioned between the tablet and display.

17. The apparatus of claim 14 wherein the light emitting surface comprises an active light emitting source in the housing, the light emitting surface of said source positioned between and superposed with the light reflecting surface and the display.

18. The apparatus of claim 17 wherein the active light emitting source comprises an active light emitting panel.

19. The apparatus of claim 18 wherein the panel is an electroluminescent panel.

20. The apparatus of claim 17 wherein the active light emitting source comprises a light guide having lamp means disposed on an edge thereof.

21. The apparatus of claim 20 wherein the lamp means comprises a cold cathode lamp.

22. The apparatus of claim 17 wherein the tablet is substantially transparent and is positioned between the light emitting surface and the display.

23. The apparatus of claim 22 wherein the tablet includes two arrays of wires, each wire array extending in a different coordinate direction, said wires being encased by transparent dielectric films so the wires extending in a first of the coordinate directions are insulated from the wires extending in the other of the coordinate directions.

24. The apparatus of claim 23 wherein the wires extending in said first coordinate direction are surrounded by first and second of said films, the wires extending in said second coordinate direction abutting the second film.

27. The apparatus of claim 12 wherein the light emitting surface is positioned between and superposed with the display and tablet.

28. The apparatus of claim 12 wherein the tablet is substantially transparent and is positioned between the light emitting surface and the display.

29. The apparatus of claim 28 wherein the light emitting surface comprises an active light emitting planar source positioned between and superposed with the light reflecting surface and the display.

30. The apparatus of claim 29 wherein the active light emitting planar source comprises a light guide having lamp means disposed on an edge thereof.

31. The apparatus of claim 29 wherein the active light emitting source comprises an active light emitting panel.

32. The apparatus of claim 31 wherein the panel comprises a cold cathode light emitting panel lamp.

33. The apparatus of claim 9 wherein the tablet is substantially transparent and is positioned so optical energy is transmitted through it to the display.

34. The apparatus of claim 33 further including a planar light emitting surface in the housing superposed with the surface, display and tablet.

35. The apparatus of claim 34 wherein the light emitting surface comprises a light reflecting surface.

36. The apparatus of claim 33 wherein the light emitting surface comprises an active light emitting source having a planar light emitting surface superposed with the display.

37. The apparatus of claim 36 wherein the planar light emitting surface of the active source is positioned behind the tablet.

38. The apparatus of claim 37 wherein the light emitting surface includes a reflector positioned behind the light emitting planar source of the active source.

39. The apparatus of claim 37 wherein the active light emitting source comprises an active light emitting panel.

40. The apparatus of claim 39 further including a light guide plate superposed between the panel and the tablet.

42. The apparatus of claim 33 wherein a face of the tablet forms the surface, the display being positioned behind the tablet to be responsive to ambient light transmitted through the tablet.

43. The apparatus of claim 33 wherein the tablet includes two arrays of wires, each wire array extending in a different coordinate direction, said wires being encased by transparent dielectric films so the wires in the first coordinate direction are insulated from the wires of the second coordinate direction.

44. The apparatus of claim 43 wherein the panel is an electroluminescent panel.

45. The apparatus of claim 33 wherein the tablet includes first and second transparent dielectric substrates, the first substrate including a first array of transparent conductors extending in a first coordinate direction, the second substrate including a second array of transparent conductors extending in a second coordinate direction.

46. The apparatus of claim 9 wherein the housing includes a metal shield plate that is parallel to and superposed with the display surface, light emitting surface and tablet.

47. The apparatus of claim 46 wherein the shield plate includes a wall of the housing.

49. The apparatus of claim 9 wherein the coils are excited during a first interval while the AC energy is at the predetermined frequency, and the means for exciting responds to energy coupled back to the coils from the tuned circuit during a second interval while the coils are not excited by the AC energy at the predetermined frequency.

25. The apparatus of 17 wherein the light emitting surface of the active source is positioned between and superposed with the display and tablet.

26. The apparatus of claim 25 wherein the active light emitting source comprises an active light emitting panel.

41. The apparatus of 39 wherein the active light emitting source comprises a light guide having lamp means disposed on an edge thereof.

48. The apparatus of 46 wherein the shield plate includes a plate between the tablet and an exterior wall of the housing behind the surface.

50. The apparatus of 49 further including means for detecting the phase of the current flowing in the coils during the second interval.

51. The apparatus of claim 50 wherein the phase detecting means includes first and second phase detectors responsive to the AC source and a replica of the energy coupled back to the coils during the second interval, the phase detectors being arranged so that the relative phases of waves supplied to the phase detectors are displaced 90°

.

52. In combination,

a housing,

a tablet in the housing

an AC energy source,

an implement for tracing a line on a surface of the tablet, the implement including a tuned circuit with a predetermined reasonant frequency, the tablet including coils arranged in two coordinate directions in planes parallel to and superposed with the surface,

means for connecting the coils to the AC energy source, the AC energy source deriving approximately the same frequency as the reasonant frequency, the tuned circuit interacting with the AC energy supplied to the coils to change the AC current flowing in the coils as a function of the implement position on the tablet,

an electronic two-coordinate direction display in the housing configured as a plate superposed with and lying in a plane parallel to the tablet and the surface, and

means responsive to the AC current flowing in the coils for activating the display so the implement position is displayed on the surface.

53. The combination of claim 52 wherein the means for indicating implement position includes means for detecting the amplitude of the current flowing in the coils.

54. The combination of claim 53 further including means for detecting the phase of the current flowing in the coils.

55. The combination of claim 52 wherein the coils are excited during a first interval while the AC energy is at the predetermined frequency, and the means for activating responds to energy coupled back to the coils from the tuned circuit during a second interval while the coils are not excited by the AC energy at the predetermined frequency.

56. Apparatus for detecting and displaying the position of an implement on a display surface, the implement including a structure interacting with a position detecting AC field derived from the apparatus, comprising a housing, an electronic two-coordinate direction display configured as a plate in the housing, the display including the display surface as an exterior face of the housing, an active light source having a light emitting surface positioned in the housing for illuminating the display surface, an optically transparent tablet positioned in the housing between the light emitting surface and the display for detecting the position of the implement on the display surface, a position detecting panel including means for establishing and detecting AC fields in the two coordinate directions, the AC fields interacting with the structure of the implement to cause conductors in the position sensor to derive signals indicative of the position of the implement on the display surface, means responsive to the derived signals for activating the display so the position of the implement on the display surface is displayed on the display surface, the display surface, light emitting surface and position detecting panel being superposed and lying in different parallel planes.

57. The apparatus of claim 56 wherein the tablet includes two arrays of wires, each wire array extending in a different one of said coordinate directions, said wires being encased by transparent dielectric films so the wires extending in a first of the coordinate directions are insulated from the wires extending in a second coordinate direction.

58. The apparatus of claim 57 wherein the panel is an electroluminescent panel.

59. The apparatus of claim 56 wherein the tablet includes first and second transparent dielectric substrates, the first substrate including a first array of transparent conductors extending in a first of the coordinate directions, the second substrate including a second array of transparent conductors extending in a second of the coordinate directions.

60. The apparatus of claim 56 wherein the housing includes a metal shield plate lying in a plane that is parallel to the planes of the display surface, light emitting surface and tablet.

61. The apparatus of claim 60 wherein the shield plate includes a wall of the housing.

62. The apparatus of claim 60 wherein the shield plate includes a plate between the tablet and an exterior wall of the housing behind the surface.

63. A position detecting device having:

a position pointer having a tuning circuit; and

a tablet for position detection having electric wave generating means for generating an electric wave at a frequency equal to the resonance frequency of said tuning circuit, and electric wave detecting means for detecting an electric wave reflected by said tuning circuit,

coordinate values of a position designated with said position pointer on a position detecting section of said tablet being detected by exchange of electric waves between said position pointer and said tablet,

said position detecting device comprising coordinate display means superposed with said tablet for displaying said designated position with coordinates corresponding to said coordinate values, said display means being a transmission type of liquid crystal display unit.

64. A position detecting device having:

a position pointer having a tuning circuit; and

a tablet for position detection having electric wave generating means for generating an electric wave at a frequency equal to the resonance frequency of said tuning circuit, and electric wave detecting means for detecting an electric wave reflected by said tuning circuit,

coordinate values of a position designated with said position pointer on a position detecting section of said tablet being detected by exchange of electric waves between said position pointer and said tablet,

said position detecting device comprising coordinate display means superposed with said tablet for displaying said designated position with coordinates corresponding to said coordinate values, said display means being of a plasma display type.

65. A position detecting device having:

a position pointer having a tuning circuit; and

a tablet for position detection having electric wave generating means for generating an electric wave at a frequency equal to the resonance frequency of said tuning circuit, and electric wave detecting means for detecting an electric wave reflected by said tuning circuit,

coordinate values of a position designated with said position pointer on said tablet being detected by exchange of electric waves between said position pointer and said tablet,

said position detecting device comprising;

coordinate display means for displaying said designated position with coordinates corresponding to said coordinate values; and

a back light for illuminating said display means from below, a reflecting plate for reflecting light emitted from said back light toward said display means disposed over said back light.

66. A position detecting device having:

a position pointer having a tuning circuit; and

a tablet for position detection having electric wave generating means for generating an electric wave at a frequency equal to the resonance frequency of said tuning circuit, and electric wave detecting means for detecting an electric wave reflected by said tuning circuit,

coordinate values of a position designated with said position pointer on said tablet being detected by exchange of electric waves between said position pointer and said tablet,

said position detecting device comprising;

coordinate display means for displaying said designated position with coordinates corresponding to said coordinate values; and

a back light for illuminating said display means from below, said back light being constituted by an electroluminescent element.