Touch-screen arrangement

• US 5,184,115 A
• Filed: 06/04/1990
• Issued: 02/02/1993
• Est. Priority Date: 06/04/1990
• Status: Expired due to Term

• Current Assignee: NCR Corporation (NCR Voyix Corporation)
• Original Assignee: AT&T, Inc.
• Inventors: Smith, Douglas C., Black, Edward P.
• Primary Examiner(s): Brier, Jeffery A.
• Assistant Examiner(s): Chin, Jick
• Application Number:
  US07/532,721
• Time in Patent Office: 974 Days
• Field of Search: 340/712, 340/708, 340/707, 340/706, 178/18, 178/19, 324/121 R, 324/226, 324/239
• US Class Current: 345/173
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

In an arrangement wherein an inquiry and a choice of respones thereto are displayed on a CRT screen, a selection is made by holding a touch-screen device against the area of the screen corresponding to the desired response. Such a touch-screen device is designed to have an inductive coil in its tip. When an electron beam which scans the CRT screen sweeps across the tip of the touch-screen device, an electrical signal is induced on the coil. The touch-position or the selection is determined based on a knowledge of the position of the electron beam on the screen at the time of the electrical signal induction.

Claims

1. Apparatus for use with a CRT, said CRT emitting an electron beam which scans a viewing screen, said apparatus comprising

means including an inductive coil for detecting a magnetic field generated by the scan of said electron beam on said viewing screen, and

means for activating a generation of a signal indicative of a detection of said magnetic field.

2. The apparatus of claim 1 wherein said CRT is included in a television set.

3. The apparatus of claim 1 wherein said CRT is included in a computer monitor.

4. The apparatus of claim 1 wherein said signal is an electrical signal.

5. Apparatus for use with a display device having a screen which is scanned by an electron beam, said apparatus comprising

means including an inductive coil for sensing a magnetic field generated by the scan of said electron beam, and

means responsive to the sensed magnetic field for determining the time instant at which said electron beam scans across a particular point of said screen.

6. The apparatus of claim 5 wherein said screen is associated with a cathode ray tube (CRT).

7. The apparatus of claim 5 wherein said display device is a television set.

8. The apparatus of claim 5 wherein said display device is a computer monitor.

9. A system having a cathode ray tube (CRT) wherein an electron beam scans a screen associated with said CRT, said system comprising

means for displaying a menu of selections on said screen, and

means including an inductive coil for detecting a magnetic field generated by the scan of said electron beam on different areas of said screen, each of said different areas corresponding to a particular one of said selections in said menu.

10. The system of claim 9 wherein said CRT is included in a television set.

11. The system of claim 9 wherein said CRT is included in a computer monitor.

12. A system having a CRT screen which is scanned by an electron beam, said system comprising

means for displaying a menu of choices on said CRT screen,

means including an inductive coil for detecting a magnetic field generated by the scan of said electron beam on said CRT screen, said detecting means being placed over a particular area of said CRT screen corresponding to a selected one of said choices, and

means for determining the location of said particular area on said CRT screen to identify said selected choice.

13. The system of claim 12 wherein said CRT screen is included in a television set.

14. The system of claim 12 wherein said CRT screen is included in a computer monitor.

15. A method for use with a display device having a screen which is scanned by an electron beam, said method comprising the steps of

sensing a magnetic field generated by the scan of said electron beam,using an inductive coil and

determining, in response to the sensed magnetic field, the time instant at which said electron beam scans across a particular point of said screen.

16. The method of claim 15 wherein said screen is associated with a cathode ray tube (CRT)

17. The method of claim 15 wherein said display device is a television set.

18. The method of claim 15 wherein said display device is a computer monitor.

19. A method for use in a system having a cathode ray tube (CRT) wherein an electron beam scans a screen associated with said CRT, said method comprising the steps of

displaying a menu of selections of said screen, and

detecting a magnetic field generated by the scan of said electron beam on different areas of said screen, using an inductive coil each of said different areas corresponding to a particular one of said selections in said menu.

20. The method of claim 19 wherein said CRT is included in a television set.

21. The method of claim 19 wherein said CRT is included in a computer monitor.

22. A method for use in a system having a CRT screen which is scanned by an electron beam, said method comprising the steps of

displaying a menu of choices on said CRT screen,

detecting a magnetic field generated by the scan of said electron beam on said CRT screen by means of a sensor, said sensor comprising an inductive coil being placed over a particular area of said CRT screen corresponding to a selected one of said choices, and

determining the location of said particular area on said CRT screen to identify said selected choice.

23. The method of claim 22 wherein said CRT screen is included in a television set.

24. The method of claim 22 wherein said CRT screen is included in a computer monitor.

25. A method for use with a CRT having a screen associated therewith, said CRT emitting an electron beam which scans said screen, said means comprising the steps of

detecting a magnetic field generated by the scan of said electron beam on said screen, using an inductive coil and

generating a signal indicative of a detection of said magnetic field.

26. The method of claim 25 wherein said CRT is included in a television set.

27. The method of claim 25 wherein said CRT is included in a computer monitor.

28. The method of claim 25 wherein said signal is an electrical signal induced in the presence of said magnetic field.

29. Apparatus for use with a CRT, said CRT emitting an electron beam which scans a viewing screen, said apparatus comprising

means including an inductive coil responsive to the magnetic field generated by the scan of the electronic beam for generating an induced electrical signal,

means responsive to said induced electrical signal, whose amplitude exceeds a predetermined amplitude level, for generating a pass signal, and

means responsive to a receipt of synchronization signals marking the start of each scan of said electron beam and a receipt of said pass signal for determining the length of time by which the last received synchronization signal respective of said pass signal leads said pass signal, said determining means generating a signal indicative of the value of said length of time.

30. The apparatus of claim 29 wherein said induced electrical signal comprises spikes, and said generating means is responsive to the highest spike of each signal whose amplitude exceeds a predetermined threshold.