Infrared touch screen device for a video monitor

• US 5,162,783 A
• Filed: 12/14/1990
• Issued: 11/10/1992
• Est. Priority Date: 07/23/1990
• Status: Expired due to Fees

• Current Assignee: Akzo Nobel N.V. (Nouryon BV)
• Original Assignee: Akzo Nobel N.V. (Nouryon BV)
• Inventors: Moreno, Mario
• Primary Examiner(s): Weldon, Ulysses
• Assistant Examiner(s): CHOW, DOON Y
• Application Number:
  US07/627,229
• Time in Patent Office: 697 Days
• Field of Search: 340/706, 340/709, 340/712, 341/31, 250/221, 718/18, 718/19
• US Class Current: 345/175
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

An infrared touch screen device that is externally adaptable to a video monitor for serving as an input device to a computer connected to the monitor. A bezel is adapted to be releasably secured over a viewing end of a video monitor. A plurality of infrared emitters are disposed along the bezel to form a grid of vertical and horizontal infrared beams in the interior space of the bezel when the emitters are activated. A plurality of infrared sensors are disposed along the bezel. Each sensor is optically aligned with an oppositely disposed one of the emitters. An activating circuit is mounted on the bezel for sequentially activating, in a predetermined sequence, respective ones of the emitters. A scanning circuit is mounted on the bezel for sequentially scanning the sensors in a sequence corresponding to the predetermined sequence, the sensors each producing output signals corresponding to the presence and absence, respectively of an infrared beam emitted by an oppositely disposed infrared emitter. A communication device couples the output signals of the sensors to an input port of a computer connected to the monitor.

Claims

1. An infrared touch screen device that is externally adaptable to a video monitor for serving as an input device to an electronic device connected to the monitor, comprising:

a bezel adapted to be releasably secured over a viewing end of a video monitor, said bezel defining an interior space through which a screen of a monitor to which said bezel is attached can be viewed;

eams in said interior space when said emitters are activated, wherein said emitters are semiconductor devices which emit infrared light when an activating current is passed therethrough;

a plurality of infrared sensors disposed along said bezel, each said sensor being optically aligned with an oppositely disposed one of said emitters;

activating means mounted on said bezel for activating said emitters in a predetermined sequence, said activating means includes means for passing an activating current through respective ones of said emitters in said predetermined sequence;

scanning means mounted on said bezel for scanning said sensors in a sequence corresponding to said predetermined sequence and lagging said predetermined sequence by a predetermined time delay, said sensors each producing output signals corresponding to the presence and absence, respectively, of infrared light emitted by an oppositely disposed infrared emitter; and

communication means for coupling the output signals of said sensors to an input port of an electronic device connected to the monitor.

2. A device as defined in claim 1, further comprising a planar transparent screen disposed in said interior space and fastened to said bezel.

3. A device as defined in claim 2, wherein said emitters and said sensors are disposed on said bezel so that the grid of infrared beams is formed on the side of said planar transparent screen remote from the screen of a monitor to which said bezel is attached.

4. A device as defined in claim 2, wherein said planar transparent screen is sealed relative to said bezel to seal against dust, humidity and liquid.

5. A device as defined in claim 2, wherein said planar transparent screen is comprised of a polycarbonate material.

6. A device as defined in claim 5, wherein said planar transparent screen is scratch resistant.

7. A device as defined in claim 5, wherein said planar transparent screen has anti-reflective characteristics.

8. A device as defined in claim 5, wherein said planar transparent screen has anti-static characteristics.

9. A device as defined in claim 1, wherein said bezel has an inner edge surrounding said interior space and further comprising an optical filter having an infrared passband fastened to said inner edge, said emitters and said sensors each being disposed on a side of said optical filter remote from said interior space so that infrared beams emitted by respective ones of said emitters pass through said optical filter a first time prior to entering said interior space and pass through said optical filter a second time upon exiting said interior space before being received by respective ones of said sensors.

10. A device as defined in claim 1, wherein said predetermined time delay is such that when a given emitter is activated by an activating current, a sensor oppositely disposed to the emitter activated immediately preceding the given emitter is concurrently scanned.

11. A device as defined in claim 10, wherein said emitters each emit infrared light over a predetermined projection angle, and said scanning means scans said sensors so that a currently scanned sensor is outside of the projection angle of a concurrently activated emitter.

12. A device as defined in claim 1, wherein said scanning means includes processing means for converting output signals corresponding to the absence of beams to coordinates identifying the location of an object which is blocking beams in said grid.

13. A device as defined in claim 12, wherein said processing means includes averaging means for determining a coordinate at a midpoint between two adjacent blocked beams in said grid.

14. A device as defined in claim 1, further comprising storage means for storing a look-up table containing electronic addresses of said emitters and said sensors;

counting means connected to said storage means for sequentially accessing said electronic addresses;

first decoder means connected to said storage means for decoding the accessed electronic addresses for activating said emitters in the predetermined sequence; and

second decoder means for decoding the accessed electronic addresses for scanning the sensors in the sequence corresponding to said predetermined sequence.

15. A device as defined in claim 14, wherein said activating means comprises an X-Y matrix of semiconductor drivers connected to said first decoder means, with each emitter being selectively activated according to said predetermined sequence by a unique pair of X and Y drivers.

16. A device as defined in claim 14, wherein said scanning means includes multiplexing means connected to said second decoder means for selectively reading the sensors in a mutually exclusive manner according to the sequence corresponding to the predetermined sequence.

17. An infrared touch screen for a video monitor for serving as an input device to an electronic device connected to the monitor, the monitor having a viewing screen and a bezel surrounding the screen, comprising:

a plurality of infrared emitters disposed along said bezel to form a grid of vertical and horizontal infrared beams in front of the screen of the monitor when said emitters are activated by an activating current;

a plurality of infrared sensors disposed along said bezel, each said sensor being optically aligned with an oppositely disposed one of said emitters;

activating means for activating said emitters in a predetermined sequence, said activating means including means for passing no activating current through said emitters in said predetermined sequence;

scanning means for scanning said sensors in a sequence corresponding to said predetermined sequence, said sensors each producing output signals corresponding to the presence and absence, respectively of an infrared beam emitted by an oppositely disposed infrared emitter, the corresponding sequence by which said scanning means scans the oppositely disposed sensors lagging said predetermined sequence by a predetermined time delay; and

communication means for coupling the output signals of said sensors to an input of an electronic device connected to the monitor.

18. A device as defined in claim 17, wherein said predetermined time delay is such that when a given emitter is activated by an activating current, a sensor oppositely disposed to the emitter activated immediately preceding the given emitter is concurrently scanned.

19. A device as defined in claim 18, wherein said emitters each emit infrared light over a predetermined projection angle, said scanning means scans said sensors so that a currently scanned sensor is outside of the projection angle of a concurrently activated emitter.

20. A device as defined in claim 18, wherein said processing means includes averaging means for determining a coordinate at a midpoint between two adjacent blocked beams in said grid.

21. A device as defined in claim 17, wherein said scanning means includes processing means for converting output signals corresponding to the absence of beams to coordinates identifying the location of an object which is blocking beams in said grid.

22. A device as defined in claim 17, further comprising storage means for storing a look-up table containing electronic addresses of said emitters and said sensors;

counting means connected to said storage means for sequentially accessing said electronic addresses;

first decoder means connected to said storage means for decoding the accessed electronic addresses for activating said emitters in the predetermined sequence; and

second decoder means for decoding the accessed electronic addresses for scanning the sensors in the sequence corresponding to said predetermined sequence.

23. A device as defined in claim 22, wherein said activating means comprises an X-Y matrix of semiconductor drivers connected to said first decoder means, with each emitter being selectively activated according to said predetermined sequence by a unique pair of X and Y drivers.

24. A device as defined in claim 22, wherein said scanning means includes multiplexing means connected to said second decoder means for selectively reading the sensors according to the sequence corresponding to the predetermined sequence.

25. An infrared touch screen device that is externally adaptable to a video monitor for serving as an input device to an electronic device connected to the monitor, comprising:

a bezel adapted to be releasably secured over a viewing end of a video monitor, said bezel defining an opening through which a screen of a monitor to which said bezel is attached can be viewed;

a planar transparent screen secured to said bezel and covering said opening;

infrared beam generating means, including a plurality of infrared emitters mounted on said bezel, for generating a grid of infrared beams adjacent said planar transparent screen on a side of said planar transparent screen remote from a screen of a video monitor to which said bezel is to be attached, said infrared beam generating means including activating means for activating said emitters in a predetermined sequence;

sensing means, including a plurality of infrared sensors mounted on said bezel, for sensing the presence and absence of respective beams in said grid and producing output signals corresponding to the presence and absence, respectively, of the infrared beams, said sensing means including scanning means for scanning said sensors in a sequence corresponding to said predetermined sequence which lags behind said predetermined sequence so that a currently scanned sensor scans a previously activated emitter; and

communication means for communicating the output signals of said sensing means to an electronic device connected to the monitor to which said bezel is attached.

26. The device as defined in claim 25, further comprising filter means having an infrared passband disposed in front of said sensing means for passing substantially only infrared light to said sensing means.

27. The device as defined in claim 26, wherein said emitters and said sensors are positioned on said bezel so that a currently scanned sensor receives substantially no infrared light from a currently activated emitter.

28. The device as defined in claim 25, wherein said infrared emitters are disposed along an inner edge of said bezel and said infrared sensors are disposed along said inner edge and are optically aligned with a respective one of said emitters.

29. A touch screen for a video monitor for producing inputs signals to an electronic device connected to the monitor, comprising:

a bezel for surrounding a viewing screen of a video monitor;

a plurality of light emitters mounted on said bezel for generating a grid of light beams in front of the screen of the monitor;

activating means coupled to said light emitters for activating said light emitters in a predetermined sequence;

a plurality of light sensors mounted on said bezel oppositely disposed from respective one of said light emitters for sensing the presence and absence of respective light beams in said grid and producing output signals corresponding to the presence and absence, respectively, of the light beams;

scanning means coupled to said sensors for scanning said sensors in a sequence corresponding to and lagging behind said predetermined sequence so that a currently scanned sensor scans a previously activated emitter; and

communication means for communicating the output signals of the scanned sensors to an electronic device connected to the monitor.