Methods and systems for detecting selections on a touch screen display

• US 20070024598A1
• Filed: 07/29/2005
• Published: 02/01/2007
• Est. Priority Date: 07/29/2005
• Status: Active Grant

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies Fiber IP Singapore PTE Limited (Broadcom, Inc.)
• Inventors: Helbing, Rene, Miller, Jeffrey, Butterworth, Mark
• Granted Patent: US 7,629,968 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G06F 2203/04109 FTIR in optical digitiser, i.e. touch detection by frustrating the total internal reflection within an optical waveguide due to changes of optical properties or deformation at the touch location
• CPC Class Codes: G06F 3/0428 by sensing at the edges of the touch surface the interruption of optical paths, e.g. an illumination plane, parallel to the touch surface which may be virtual sensing beam interruptions in a planar beam grid of an optical touch-screen G06F3/0421

Abstract

Light beam focusing components direct light from the top surface of a touch screen display to one or more imagers. The imager or imagers capture one or more images of the top surface of the touch screen display. A processing unit analyzes the image or images to determine the position of an input device on or near the top surface of the touch screen display.

Claims

1. A system for a touch screen display system, comprising:

light beam focusing components operable to direct light from a top surface of a touch screen display to one or more imagers operable to capture images using the directed light; and

a processing unit operable to receive the one or more captured images and determine positional information for an input device positioned on or near the top surface of the touch screen display using at least one captured images.

2. The system of claim 1, further comprising one or more light sources operable to emit light towards the top surface of the touch screen display.

3. The system of claim 2, wherein the one or more imagers comprise a fist imager and a second imager and the light beam focusing components comprise a first collimating lens positioned in a first optical path between a first light source and the first imager and a second collimating lens positioned in a second optical path between a second light source and the second imager.

4. The system of claim 3, wherein the light beam focusing components further comprise a first straight mirror positioned between the first collimating lens and the first imager and a second straight mirror positioned between the second collimating lens and the second imager.

5. The system of claim 3, wherein the first and second imagers and the first and second collimating lenses are constructed below the touch screen display and the light beam focusing components further comprise a first reflector assembly positioned between the first light source and the first collimating lens and a second reflector assembly positioned between the second light source and the second collimating lens.

6. The system of claim 2, wherein the one or more light sources comprise a first light source propagating light at a first wavelength and a second light source propagating light at a second wavelength.

7. The system of claim 6, wherein the one or more images comprise a first imager and the light beam focusing components comprise:

a first reflector assembly and a first collimating lens positioned in a first direction, wherein the first collimating lens is constructed below the touch screen display and the first reflector assembly is operable to direct light to the first collimating lens; and

a second reflector assembly and a second collimating lens positioned in a second direction relative to the first direction, wherein the second collimating lens is constructed below the touch screen display and the second reflector assembly is operable to direct light to the second collimating lens.

8. The system of claim 7, further comprising a beam combiner operable to receive light from the first and second collimating lenses and direct the light to the first imager.

9. The system of claim 8, wherein the first imager comprises a patterned filter layer operable to discriminate between the light propagating at the first wavelength and the light propagating at the second wavelength.

10. The system of claim 2, wherein the one or more imagers comprise a fist imager and a second imager and the light beam focusing components comprise a first Fresnel lens positioned in a first optical path between a first light source and the first imager and a second Fresnel lens positioned in a second optical path between a second light source and the second imager.

11. The system of claim 10, wherein the first Fresnel lens comprises a first TIR Fresnel lens and the second Fresnel lens comprises a second TIR Fresnel lens.

12. The system of claim 10, wherein the light beam focusing components further comprise a first curved mirror positioned between the first Fresnel lens and the first imager and a second curved mirror positioned between the second Fresnel lens and the second imager.

13. The system of claim 2, wherein the one or more imagers comprise a fist imager and a second imager and the light beam focusing components comprise a first microlens array and a first plurality of guides operable to receive light from a first light source and direct the light to the first imager and a second microlens array and a second plurality of guides operable to receive light from a second light source and direct the light to the second imager.

14. A method for obtaining positional information for an input device on or near a top surface of a touch screen display, comprising:

directing light from the top surface of the touch screen display;

capturing one or more images of the top surface of the touch screen display using the directed light; and

determining positional information for the input device using at least one of the one or more captured images.

15. The method of claim 14, further comprising emitting light towards the top surface of the touch screen display.

16. The method of claim 14, wherein directing light from the top surface of the touch screen display comprises focusing light from the top surface of the touch screen display towards one or more imagers.

17. The method of claim 14, wherein directing light from the top surface of the touch screen display comprises reflecting light from the top surface of the touch screen display towards one or more imagers.

18. The method of claim 15, wherein the light propagates at two different wavelengths.

19. The method of claim 18, wherein directing light from the top surface of the touch screen display comprises focusing light from the top surface of the touch screen display towards a beam combiner.

20. The method of claim 14, wherein directing light from the top surface of the touch screen display comprises guiding light from the top surface of the touch screen display towards one or more imagers.