LASER INTERFERENCE DEVICE FOR TOUCH SCREENS

• US 20100002238A1
• Filed: 10/09/2007
• Published: 01/07/2010
• Est. Priority Date: 10/11/2006
• Status: Abandoned Application

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Presura, Cristian, Garcia Molina, Gary Nelson, Destura, Galileo June
• Application Number:
  US12/444,706
• Publication Number:
  US 20100002238A1
• Time in Patent Office: Days
• US Class Current: 356/450
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

A system and method for location determination by laser interference detection uses a wide beamwidth laser projection (301) across a planar area (300). A lens system (222) is used to provide the wide beamwidth projection, and a split-beam system (225) is used to correlate interference patterns to particular segments of the wide beamwidth projection. The reflected interference beams are detected on a detector array (240) that is configured to detect the undulations corresponding to objects within the wide beamwidth projection.

Claims

1. A system comprising:

a source (220, 222) of a wide beamwidth projection (203),

an array of detectors (240),

a beam splitter (225) that is configured to provide two projections (201, 202) of the wide beamwidth projection (203);

a first projection (201) that extends across a planar area, and

a second projection (202) that extends across the array of detectors, and

a detection system (250) that is configured to detect interferences caused by reflections of the first projection (201) onto the array of detectors (240), and to determine therefrom a presence of one or more objects (150) in the planar area.

2. The system of claim 1, wherein

the source (220, 222) provides a wide beamwidth laser projection.

3. The system of claim 1, wherein

the source (220, 222) includes a cylindrical lens (222) that provides the wide beamwidth projection.

4. The system of claim 1, including

a lens system (315) that is configured to direct the reflections of the first projection (301) onto the array of detectors (312).

5. The system of claim 4, wherein

the lens system (315) is configured to direct the reflections of rays (201b) of the first projection (201) to areas (240b) of the array of detectors (240) where corresponding rays (202b) of the second projection (202) strike the array of detectors (240).

6. The system of claim 1, wherein

the detection system (250) is configured to determine a location of at least one of the objects (150) relative to the planar area.

7. The system of claim 6, wherein

the detection system (250) is configured to determine the location based on the interferences detected from a plurality of detectors of the array (240).

8. The system of claim 6, wherein

the detection system (250) is configured to determine the location based on multiple measures of the interferences over time.

9. The system of claim 1, including

a display screen (300) adjacent the planar area.

10. The system of claim 1, wherein

the detection system (250) is configured to control an energy level associated with the projections.

11. A method comprising:

providing (220, 222) a wide beamwidth projection,

splitting (225) the wide beamwidth projection to provide two projections;

a first projection (201) that extends across a planar area, and

a second projection (202) that extends across an array of detectors (240),

detecting (240) interferences caused by reflections of the first projection onto the array of detectors, and

determining (250) from the interferences a presence of one or more objects (150) in the planar area.

12. The method of claim 11, wherein

the wide beamwidth projection includes a laser projection (220).

13. The method of claim 11, including

providing (220, 222) the wide beamwidth projection includes spreading (222) a narrowbeam projection via a cylindrical lens that provides the wide beamwidth projection

14. The method of claim 11, including

directing the reflections of the first projection onto the array of detectors (312) via a lens system (315).

15. The method of claim 14, wherein

rays (201b) of the reflections of the first projection (201) are directed to strike the array of detectors (240) at areas (240b) where corresponding rays (202b) of the second projection (202) strike the array of detectors (240).

16. The method of claim 11, including

determining (250) a location of at least one of the objects (150) relative to the planar area.

17. The method of claim 16, wherein

determining (250) the location includes determining the location based on the interferences detected from a plurality of detectors of the array (240).

18. The method of claim 16, wherein

determining (250) the location includes determining the location based on multiple measures of the interferences over time.

19. The method of claim 11, including

displaying information on a display screen (300) adjacent the planar area.

20. The method of claim 11, including

controlling (250) an energy level associated with the projections.