TOUCH SCREEN

• US 20080111797A1
• Filed: 11/09/2007
• Published: 05/15/2008
• Est. Priority Date: 11/15/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: LEE, Yu-Sheop
• Granted Patent: US 8,035,625 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06F 3/0423 using sweeping light beams, e.g. using rotating or vibrating mirror

Abstract

A touch screen includes a display screen having an upper surface that provides picture information, and an optical module that emits rays in directions that can be parallel with the upper surface of the screen. When an object, such as a stylus, pen or a finger is placed on the screen to select a portion of the picture information provided on the screen, at least a portion of the rays are reflected off of the object and detected in order to determine a position of the object on the screen. The position of the object can be calculated in various ways including calculating a position of the object based on a phase delay of the reflected rays, or based on an intensity of the reflected rays, or based on an incidence angle of the reflected rays.

Claims

1. A touch screen comprising:

picture means having an upper surface providing picture information; and

an optical module for emitting rays in directions parallel with the upper surface of the picture means and detecting rays reflected by an object adjacent the upper surface of the picture means and in a path of at least a portion of the parallel rays.

2. The touch screen as recited in claim 1, further comprising a calculating unit for calculating a position of the object on the upper surface picture means from the reflected rays detected in the optical module.

3. The touch screen as recited in claim 2, wherein the calculating unit calculates a position of the object based on a phase delay of the reflected rays.

4. The touch screen as recited in claim 2, wherein the calculating unit calculates a position of the object based on an intensity of the reflected rays.

5. The touch screen as recited in claim 2, wherein the calculating unit calculates a position of the object based on an incidence angle of the reflected rays.

6. The touch screen as recited in claim 1, wherein the picture means comprise a liquid crystal display.

7. The touch screen as recited in claim 1, wherein the optical module comprises:

a light source for outputting rays in directions parallel with the upper surface of the picture means on the upper surface of the picture means;

an optical sensor for detecting rays reflected on the upper surface of the picture means; and

an optical filter positioned between the light source and the optical sensor, wherein rays emitted from the light source are penetrated through the optical filter to the upper part of the picture means, and for reflecting the rays reflected on the upper surface of the picture means to the optical sensor.

8. The touch screen as recited in claim 7, wherein the optical module comprises:

a first lens system positioned between the light source and the optical filter, the first lens system diffusing rays generated in the light source so that the rays have an emission angle covering whole area of the picture means; and

a second lens system positioned between the optical filter and the optical sensor, the second lens system collecting the rays entering the optical sensor from the optical filter.

9. The touch screen as recited in claim 7, wherein the optical sensor comprises an image sensor having a form in which a plurality of light detectors are arranged as respective pixel units.

10. The touch screen as recited in claim 2, wherein the calculating unit calculates the position of the object based on

x=r cos(A),

wherein X and Y are random coordinates perpendicular with each other on the touch screen, r is a distance from a reflectable object to the optical module, and A is an angle with respect to an optical axis of a ray reflected in the optical module.

11. The touch screen as recited in claim 2, wherein the calculating unit calculates the position of the object based on

y=r sin(A),

wherein X and Y are random coordinates perpendicular with each other on the touch screen, r is a distance from a reflectable object to the optical module, and A is an angle with respect to an optical axis of a ray reflected in the optical module.

12. The touch screen as recited in claim 2, wherein the position of the object indicates a portion of the picture information selected.

13. A touch screen comprising:

picture means having an upper surface providing a user with picture information;

a light source for generating rays;

an optical sensor for detecting rays reflected by an object on the upper surface of the picture means that is in the path of a least a portion of the rays generated by the light source; and

an optical filter positioned to face the light source and the optical sensor, rays emitted from the light source being penetrated through the optical filter to the upper surface of the picture means, and reflecting rays reflected on the upper surface of the picture means to the optical sensor.

14. The touch screen as recited in claim 13, further comprising a lens system positioned between the optical filter and the optical sensor.

15. The touch screen as recited in claim 13, wherein the optical filter comprises a slanted surface formed on a part of its upper surface, wherein the upper surface corresponds to the optical sensor and the light source.

16. The touch screen as recited in claim 15, further comprising a camera means for obtaining an image of an object on the upper surface of the picture means, so that a distance of an object on the upper surface of the picture means is calculated according to a number of pixels in which an output is detected.

17. A method for providing a touch screen, comprising the steps of

providing picture information on an upper surface of a touch screen;

emitting rays in directions parallel with the upper surface of the touch screen and detecting rays reflected by an object adjacent the upper surface of the picture means and in a path of at least a portion of the parallel rays;

wherein the object is positioned to select a portion of the picture information provided on the upper surface of the touch screen;

18. The method according to claim 17, further comprising the step of calculating a position of the object on the upper surface of the touch screen from the reflected rays that were detected.

19. The method according to claim 18, wherein the calculating of the position of the object is based on a phase delay of the reflected rays.

20. The method according to claim 18, wherein the calculating of the position of the object is based on an intensity of the reflected rays.

21. The method according to claim 18, wherein the calculating of the position of the object is based on an incidence angle of the reflected rays.