LIGHT-BASED TOUCH SCREEN USING ELONGATED LIGHT GUIDES

• US 20110210946A1
• Filed: 03/22/2011
• Published: 09/01/2011
• Est. Priority Date: 12/10/2002
• Status: Active Grant

• Current Assignee: Neonode, Inc.
• Original Assignee: Neonode, Inc.
• Inventors: Shain, Joseph, Goertz, Magnus, Eriksson, Thomas, Pettersson, Robert, Sparf, Lars, Jansson, Anders, Karlsson, John, Kvist, Niklas
• Granted Patent: US 9,389,730 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06F 3/0425 using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected tracking a projected light spot to determine a position on a display surface G06F3/0386
• 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

A touch screen including a housing, a display mounted in the housing, a plurality of collimating lenses mounted in the housing and arranged along a first edge of the display, a plurality of light pulse emitters mounted in the housing that are spaced apart from and serially transmit light pulses through the collimating lenses over the display, a light guide mounted in the housing along the edge of the display opposite the first edge, for receiving the light pulses, the light guide including a reflective strip that reflects light pulses to one end of the light guide, a light pulse receiver mounted in the housing near the one end of the light guide, for receiving the reflected light pulses, and a calculating unit, mounted in the housing and connected to the receiver, for determining a location of a pointer on the display that partially blocks light pulses transmitted by the emitters, based on outputs of the receiver.

Claims

1. A touch screen comprising:

a housing;

a display mounted in said housing;

a plurality of collimating lenses mounted in said housing and arranged along a first edge of said display;

a plurality of light pulse emitters mounted in said housing that are spaced apart from and serially transmit light pulses through said collimating lenses over said display;

a light guide mounted in said housing along the edge of said display opposite the first edge, for receiving the light pulses, the light guide comprising a reflective strip that reflects light pulses to one end of the light guide;

a light pulse receiver mounted in said housing near the one end of said light guide, for receiving the reflected light pulses; and

a calculating unit, mounted in said housing and connected to said receiver, for determining a location of a pointer on said display that partially blocks light pulses transmitted by said emitters, based on outputs of said receiver.

2. The touch screen of claim 1, wherein said light guide further comprises a collimating lens for collimating received light pulses onto said receiver strip.

3. The touch screen of claim 2, wherein said light guide further comprises a plurality of micro-lenses for mufti-directional collimation of received light pulses onto said reflective strip.

4. The touch screen of claim 1, wherein said reflective strip reflects the received light pulses to both ends of said light guide, the touch screen further comprising a second light pulse receiver mounted in said housing near a second end of said light guide for receiving the reflected light pulses, and wherein said calculating unit is also connected to said second light pulse receiver and determines the location of the pointer on said display based on outputs of said first and second receivers.

5. The touch screen of claim 4, wherein said first and second light pulse receivers are activated serially.

6. The touch screen of claim 4, wherein said first and second light pulse receivers are activated in parallel.

7. A touch screen comprising:

a housing;

a display mounted in said housing;

a light guide mounted in said housing along a first edge of said display, the light guide comprising a reflective strip that reflects light pulses received at one end of the light guide;

a light pulse emitter mounted in said housing near the one end of said light guide, for transmitting light pulses through said light guide, wherein said reflective strip reflects the light pulses over said display;

a plurality of collimating lenses mounted in said housing along the edge of said display opposite the first edge;

a plurality of light pulse receivers mounted in said housing that are spaced apart from and receive light pulses through said collimating lenses; and

a calculating unit, mounted in said housing and connected to said receivers, for determining a location of a pointer on said display that partially blocks the light pulses transmitted by said emitter, based on outputs of said receivers.

8. A touch screen comprising:

a housing;

a display mounted in said housing;

a light guide mounted in said housing along a first edge of said display, the light guide comprising a reflective strip that reflects light pulses received at either end of the light guide;

a plurality of light pulse emitters mounted in said housing near each end of said light guide, for transmitting light pulses through said light guide, wherein said reflective strip reflects the light pulses over said display;

a plurality of collimating lenses mounted in said housing along the edge of said display opposite the first edge;

a plurality of light pulse receivers mounted in said housing that are spaced apart from and receive light pulses through said collimating lenses; and

a calculating unit, mounted in said housing and connected to said receivers, for determining a location of a pointer on said display that partially blocks the light pulses transmitted by said emitters, based on outputs of said receivers.

9. The touch screen of claim 8, wherein said light pulse emitters are activated serially.

10. The touch screen of claim 9, wherein said calculating unit computes a deviation between an output value from each said receiver and an expected value for each said receiver when the light pulses are not blocked, and wherein a first expected value corresponds to an emitter at a first end of said light guide being activated, and a second expected value corresponds to an emitter at the other end of said light guide being activated.

11. The touch screen of claim 10, wherein the first and second expected values for at least one of said receivers are different.

12. The touch screen of claim 8, wherein said light pulse receivers are activated in parallel.

13. The touch screen of claim 8, wherein said light pulse receivers are activated serially and in parallel.

14. The touch screen of claim 8, wherein said light guide further comprises a collimating lens for collimating the reflected light pulses over said display.

15. The touch screen of claim 8, wherein said light guide further comprises a plurality of micro-lenses for mufti-directional collimation of the reflected light pulses over said display.