DISPLAY DEVICE INCLUDING OPTICAL SENSING FRAME AND METHOD OF SENSING TOUCH

• US 20110148819A1
• Filed: 12/15/2010
• Published: 06/23/2011
• Est. Priority Date: 12/18/2009
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Yu, Byung-Chun
• Granted Patent: US 8,659,561 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• 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 method of sensing touch on a display device having an optical sensing frame includes emitting first light from a sensor module, receiving a first reflection at the sensor module, emitting second light from a waveguide, receiving a second reflection at the waveguide, and if a touch is made on an optical sensing frame, detecting that reflections of the first and the second light are interfered and determining a change in the quantity of the first and second reflection received to determine the touch.

Claims

1. A method of sensing touch on a display device having an optical sensing frame comprising:

emitting first light from a sensor module;

receiving a first reflection at the sensor module;

emitting second light from a waveguide;

receiving a second reflection at the waveguide; and

if a touch is made on an optical sensing frame;

detecting that reflections of the first and the second light are interfered, and

determining a change in the quantity of the first and second reflection received to determine the touch.

2. The method of claim 1 wherein the sensor module comprises an optical sensor module.

3. The method of claim 2, wherein the optical sensor module includes two cameras disposed at both ends of the waveguide.

4. The method of claim 3,

wherein a first determination of the position of the touch is made by triangulation of the touch based on the first reflection.

5. The method of claim 4, wherein a second determination of a position along an axis parallel to a length of the waveguide of the touch is made based on the second reflection.

6. The method of claim 5, wherein:

if a multi touch is made, determining actual positions of the multi touch based on the first and the second determination.

7. The method of claim 6, wherein the first determination comprises actual position information of the multi touch and ghost position information, the actual position information and the ghost position information each including a first axis information and a second axis information, the method further comprising:

comparing the first axis information and the second determination to determine the actual positions of the multi touch.

8. The method of claim 5, wherein:

if a touch is made on a dead zone, determining an actual position of the touch based on the second determination.

9. The method of claim 3, wherein if a touch is made on a dead zone, a third determination of the position of the touch is made by triangulation of the touch based on the first reflection and the second reflection.

10. A display device including an optical sensing frame, comprising:

a display panel;

two optical sensor modules disposed on the display panel operable to emit first light and receive a first reflection;

a wave guide disposed at a side of the display panel for emitting second light and receiving a second reflection; and

an optical reflecting member disposed at each of the remaining sides of the display panel for reflecting the first light as the first reflection and reflecting the second light as the second reflection.

11. The device of claim 10, further comprising a casing configured to enclose the display panel, the optical sensor module, the wave guide and the optical reflecting member.

12. The device of claim 10, wherein the first light and the second light is infrared light.

13. The device of claim 10, further comprising a touch control unit coupled to the two optical sensor modules and the wave guide unit, wherein the touch control unit is operable to:

detect that reflections of the first and second light are interfered,

determine a change in the quantity of the first and second reflection received to determine a touch.

14. The device of claim 13, wherein the touch control unit is further operable to make a first determination of a position of the touch by triangulation of the touch based on the first reflection.

15. The device of claim 14, wherein the touch control unit is further operable to make a second determination of a position along an axis parallel to a length of the waveguide of the touch based on the second reflection.

16. The device of claim 15, wherein the touch control unit is further operable to:

if a multi touch is made, determine actual positions of the multi touch based on the first and the second determination.

17. The device of claim 16, wherein the first determination comprises actual position information of the multi touch and ghost position information, the actual position information and the ghost position information each including a first axis information and a second axis information, the touch control unit further operable to:

compare the first axis information and the second determination to determine the actual positions of the multi touch.

18. The device of claim 15, wherein the touch control unit is further operable to:

determine an actual position of the touch based on the second determination.

19. The device of claim 13, wherein if the touch is made on a dead zone, a third determination of the position of the touch is made by triangulation of the touch based on the first reflection and the second reflection.

20. The device of claim 10, wherein:

the two optical sensor modules are disposed on the same side of the display panel as the waveguide, the each of the two optical sensor module disposed at both opposite ends of the waveguide.

21. The device of claim 20, wherein each of the two optical sensor modules has an angle of view of about 90°

˜

100°

with respect to a surface perpendicular to a surface of the two optical sensor modules.

22. The device of claim 20, wherein each of the two optical sensor modules comprises a line sensor array or a two-dimensional sensor array.

23. The device of claim 10, wherein the waveguide comprises a stacked structure including a light emitting layer operable to emit the second light and a light receiving layer operable to receive the second reflection.

24. The device of claim 23, wherein the light emitting layer includes an infrared LED for emitting the second light, a light splitter for splitting the second light emitted from the infrared LED, and a plurality of first optical fibers for transmitting the second light from the light splitter for emission from a plurality of points with respect to an axis parallel to a length of the waveguide.

25. The device of claim 23, wherein the light receiving layer includes a plurality of second optical fibers for transmitting the received second reflection and a line sensor array or a two-dimensional sensor array connected to the second optical fibers.

26. The device of claim 10, wherein the optical reflecting member comprises:

a second optical filter for transmitting lights having an infrared band; and

a retro-reflecting layer for retro-reflecting the first and the second light in to the first and the second reflection,

wherein the retro-reflecting layer is formed of a cube-corner type structure.