Optical Touch Display System

• US 20120044213A1
• Filed: 11/03/2011
• Published: 02/23/2012
• Est. Priority Date: 09/23/2009
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Lu, Chih-Hung, Chen, Hsin-Chia, Hsu, En-Feng, Liao, Chi-Chieh, Gu, Ren-Hau, Yang, Shu-Sian, Huang, Yu-Hao
• Granted Patent: US 9,645,681 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• CPC Class Codes: G01S 17/48 Active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves
• CPC Class Codes: G01S 7/491 Details of non-pulse systems
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating
• 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

Optical touch display system includes a light source, a reflector, an image sensor, and a processing device. The light source emits light to at least one object directly and emits light to the at least one object via the reflector at the same time. Then the image sensor receives light reflected from the at least one object directly and light reflected via the reflector simultaneously to form a set of imaging objects which have similar color parameters on an image. Then the processing device produces a set of still image parameters of the image objects such as gravity centers and border boundaries. Based on the still image parameters, the processing device determines the coordinates of the least one object on the optical touch display.

Claims

1. An optical touch display system, comprising:

a touch region;

a light source, disposed on a periphery of the touch region, the light source positioned at least partially above the touch region, such that light rays emitted from the light source may traverse the touch region;

a reflector, disposed on at least a part of the periphery of the touch region, for reflecting the light rays emitted from the light source and generating a mirrored image of a set of touch points;

an image sensor, disposed above the light source, for receiving light rays of the light source, reflected from the set of touch points on the touch region and the reflector, and generating a two-dimensional image accordingly;

wherein the two-dimensional image comprises a set of optical images, the set of optical images comprising a set of real images corresponding to the set of touch points, and a set of virtual images corresponding to the set of touch points, generated by the light rays from the light source reflected by the reflector; and

a processing device, for generating a set of output coordinates corresponding to the set of touch points according to positions of the set of real images and the set of virtual images in the two-dimensional image.

2. The optical touch display system of claim 1, wherein the processing device generates a set of real-image lines according to positions of the set of real images and a position of the image sensor in the two-dimensional image, and generates a set of virtual-image lines according to positions of the set of virtual images and a position of a mirrored image of the image sensor in the two-dimensional image, and the processing device generates the set of output coordinates according to the set of real-image lines and the set of virtual-image lines.

3. The optical touch display system of claim 2, wherein a set of candidate coordinates are generated from a plurality of intersection points between the real-image lines and the virtual-image lines, and the processing device selects at least one coordinate from the set of candidate coordinates as the output coordinates according to distances between the candidate coordinates and the image sensor.

4. The optical touch display system of claim 1, wherein the processing device comprises:

a distance measurement device, connected to the image sensor and the light source, for controlling the light source and the image sensor, and generating a set of image distances corresponding to the set of optical images according to coordinates of the set of optical images in the two-dimensional image along a first direction;

an angle measurement device, connected to the image sensor, for generating a set of image angles corresponding to the set of optical images according to coordinates of the set of optical images in the two-dimensional image along a second direction; and

a processor, connected to the distance measurement device and the angle measurement device, for generating the set of output coordinates according to the set of image distances and the set of image angles.

5. The optical touch display system of claim 4, wherein a first real-image line of the set of real-image lines corresponds to a first real image of the set of real images, the first real image corresponds to a first touch point of the set of touch points;

a first image distance of the set of image distances corresponds to a first optical image of the set of optical images, a first image angle of the set of image angles corresponds to the first optical image of the set of optical images.

6. The optical touch display system of claim 5, wherein the first image distance represents a distance between the first optical image and the distance measurement device;

wherein the distance measurement device is close to the image sensor.

7. The optical touch display system of claim 6, further comprising a real image determination device, electrically connected to the distance measurement device and the angle measurement device, for determining whether the first optical image is the first real image according to whether a predefined relationship is fulfilled between the first image distance and the first image angle.

8. The optical touch display system of claim 7, wherein the set of candidate coordinates on the first real-image line is a first set of candidate coordinates, and the processing device selects a first candidate coordinate within the first set of candidate coordinates that is closest to the first image distance, as output coordinates of the first touch point.

9. The optical touch display system of claim 1, further comprising a light absorption component, disposed on the periphery of the touch region, for preventing the light rays of the light source from being reflected to the image sensor.

10. The optical touch display system of claim 1, wherein the image sensor is positioned close to the light source.

11. The optical touch display system of claim 1, wherein the light source is a two-dimensional light source.

12. The optical touch display system of claim 11, wherein the two-dimensional light source comprises:

a linear light source; and

a light source conversion device;

wherein the light source conversion device converts the linear light source to the two-dimensional light source, to generate the light rays on the touch region.

13. The optical touch display system of claim 12, wherein the linear light source is generated via a laser diode or a Light Emitting Diode (LED).

14. The optical touch display system of claim 11, wherein the light source conversion device is a cylindrical lens or a MEMS micro mirror module.

15. An optical touch display system, comprising:

a touch region;

a light source, on a periphery of the touch region, the light source positioned at least partially above the touch region, such that light rays emitted from the light source may traverse the touch region;

an image sensor, disposed above the light source, for receiving light rays of the light source, reflected from a set of touch points on the touch region, and generating a two-dimensional image accordingly ;

wherein the two-dimensional image comprises a set of optical images corresponding to the set of touch points;

a distance measurement device, connected to the light source and the image sensor, for controlling the light source and the image sensor, and generating a set of image distances corresponding to the set of optical images according to coordinates of the set of optical images in the two-dimensional image along a first direction;

an angle measurement device, connected to the image sensor, for generating a set of image angles corresponding to the set of optical images according to coordinates of the set of optical images in the two-dimensional image along a second direction; and

a processor, for generating a set of output coordinates according to the set of image distances and the set of image angles.

16. The optical touch display system of claim 15, wherein a first optical image of the set of optical images corresponds to a first touch point of the set of touch points;

a first image distance of the set of image distances and a first image angle of the set of image angles correspond to the first optical image.

17. The optical touch display system of claim 16, further comprising a first lens, the first lens for converging a background light or light rays reflected from the first touch point, the image sensor for sensing an energy of the light converged by the first lens, to generate M light sensing signals, and the distance measurement device comprises:

a lighting/sensing control circuit, connected to the light source, for controlling the light source to emit light during a distance sensing stage, while controlling the image sensor to sense the energy of the light converged by the first lens to generate M first light sensing signals, and controlling the light source to not emit light during a noise sensing stage, while controlling the image sensor to sense the energy of the light converged by the first lens to generate M second light sensing signals;

wherein M is an integer; and

a distance calculation circuit, connected to the image sensor, for determining an image position of the light rays reflected from the first touch point along the first direction of the image sensor according to the M first light sensing signals and the M second light sensing signals, and calculating the first image distance according to the image position, a focal distance of the first lens, a predefined distance between the light source and the image sensor.

18. The optical touch display system of claim 17, wherein the distance calculation circuit calculates the first image distance according to the following equation:

R_O1=(D_F×

L)/D_CS;

wherein R_O1 represents the first image distance, D_F represents the focal distance of the first lens, L represents the predefined distance between the light source and the image sensor, D_CS represents the image position.

19. An optical touch display system, comprising:

a touch region;

a light source, disposed on a periphery of the touch region, the light source positioned at least partially above the touch region, such that light rays emitted from the light source may traverse the touch region;

a first image sensor, disposed above the light source, for receiving light rays of the light source, reflected from a set of touch points on the touch region, and generating a first two-dimensional image accordingly;

wherein the first two-dimensional image comprises a first set of real images corresponding to the set of touch points;

a second image sensor, disposed on the periphery of the touch region, for receiving light rays of the light source, reflected from the set of touch points on the touch region, and generating a second two-dimensional image accordingly;

wherein the second two-dimensional image comprises a second set of real images corresponding to the set of touch points;

a distance measurement device, connected to the light source and the first image sensor, for controlling the first image sensor and the light source, and generating a first set of image distances corresponding to the first set of real images according to coordinates of the first set of real images in the two-dimensional image along a first direction; and

a processor, for generating a first set of real-image lines according to the first set of real images and a position of the first image sensor in the first two-dimensional image, and generating a second set of real-image lines according to the second set of real images and a position of the second image sensor in the second two-dimensional image, and the processing device generates a set of candidate coordinates corresponding to the set of touch points according to the first set of real-image lines and the second set of real-image lines, and generates a set of output coordinates corresponding to the set of touch points according to the set of candidate coordinates and the first set of image distances.

20. The optical touch display system of claim 19, further comprising:

a first angle measurement device, connected to the first image sensor, for generating a first set of image angles corresponding to the set of touch points according to coordinates of the first set of real images in the first two-dimensional image along a second direction; and

a second angle measurement device, connected to the second image sensor, for generating a second set of image angles corresponding to the set of touch points according to coordinates of the second set of real images in the second two-dimensional image along the second direction.

21. The optical touch display system of claim 19, wherein the first set of image distances represents distances between the set of touch points and the distance measurement device;

wherein the distance measurement device is positioned close to the image sensor.

22. The optical touch display system of claim 19, wherein a third real-image line of the first set of real-image lines corresponds to a third touch point of the set of touch points, and a third image distance of the first set of image distances corresponds to the third touch point.

23. The optical touch display system of claim 22, wherein the set of candidate coordinates on the third real-image line is a third set of candidate coordinates, and the processing device selects a third candidate coordinate within the third set of candidate coordinates that is closest to the third image distance, as output coordinates of the third touch point.

24. The optical touch display system of claim 19, further comprising a light absorption component, disposed on the periphery of the touch region, for preventing the light rays of the light source from being reflected to the image sensor.

25. The optical touch display system of claim 19, wherein the image sensor is positioned close to the light source.

26. The optical touch display system of claim 19, wherein the light source is a two-dimensional light source.

27. The optical touch display system of claim 26, wherein the two-dimensional light source comprises:

a linear light source; and

a light source conversion device;

wherein the light source conversion device converts the linear light source to the two-dimensional light source, to generate the light rays on the touch region.

28. The optical touch display system of claim 27, wherein the linear light source is generated via a laser diode or a Light Emitting Diode (LED).

29. The optical touch display system of claim 27, wherein the light source conversion device is a cylindrical lens or a MEMS micro mirror module.