LIGHT GUIDE PLATE FOR SYSTEM INPUTTING COORDINATE CONTACTLESSLY, A SYSTEM COMPRISING THE SAME AND A METHOD FOR INPUTTING COORDINATE CONTACTLESSLY USING THE SAME

• US 20090322677A1
• Filed: 08/10/2007
• Published: 12/31/2009
• Est. Priority Date: 08/10/2006
• Status: Active Grant

• Current Assignee: LG Chem Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Park, Sang-Hyun, Lee, Yeon-Keun, Choi, Hyun-Seok, Lee, Su-Rim, Kim, Jung-Doo
• Granted Patent: US 8,754,852 B2
• Time in Patent Office: Days
• US Class Current: 345/158
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

Disclosed are a light guide plate for a non-contact type coordinate input system, a system including the same, and a non-contact type coordinate input method using the same. More particularly, the present invention relates to a light guide plate for a non-contact type coordinate input system, which eliminates inconvenience of a conventional contact-type coordinate input system inputting coordinates through direct contact, and which can reduce use of sensors and optical loss as much as possible. The present invention also relates to a system including the same, and a non-contact type coordinate input method using the same.

Claims

1. A light guide plate, comprising:

a phosphor; and

at least one optical layer.

2. The light guide plate according to claim 1, wherein the phosphor is coated on a surface of a transparent layer of the light guide plate or doped into the transparent layer thereof.

5. The light guide plate according to claim 14, further comprising:

a low-refraction layer outside the light guide plate, the low-refraction layer being lower by 0.05 or more in terms of refractive index, as compared with a member having the highest refractive index among members constituting the light guide plate.

7. The light guide plate according claim 14, wherein the light guide plate comprising the phosphor has a haze of 10% or less.

9. The light guide plate according to claim 14, further comprising:

a plurality of optical sensors to detect light emitted from the phosphor receiving the light having reached the light guide plate, the optical sensors being attached to one or both of edges in a transverse direction and to one or both of edges in a longitudinal direction of the light guide plate such that a light receiving part of each optical sensor faces an edge side of the light guide plate.

3-4. -4. (canceled)

6. (canceled)

8. (canceled)

10. A non-contact type coordinate input system, comprising:

a light guide plate receiving incident light emitted from a light illuminating device, and comprising a phosphor and at least one optical layer;

a plurality of optical sensors to detect light emitted from the phosphor receiving the light having reached the light guide plate, the optical sensors being attached to one or both of edges in a transverse direction and to one or both of edges in a longitudinal direction of the light guide plate such that a light receiving part of each optical sensor faces an edge side of the light guide plate; and

a calculation unit connected to the optical sensors to calculate a coordinate set at an incident point of light reaching the light guide plate and to deliver the calculated coordinate set to a display device or a computer system connected thereto.

11. The system according to claim 10, wherein the phosphor is coated on a surface of a transparent layer of the light guide plate or doped into the transparent layer thereof.

14. The system according to claim 10, further comprising:

a low-refraction layer outside the light guide plate, the low-refraction layer being lower by 0.05 or more in terms of refractive index, as compared with a member having the highest refractive index among members constituting the light guide plate.

16. The system according to claim 10, wherein the light guide plate comprising the phosphor has a haze of 10% or less.

18. The system according to claim 10, wherein the calculation unit or the computer system connected to the calculation unit allows the display device to display the coordinate set of the incident point of light thereon.

20. The system according to claim 10, wherein the display device is one selected from LCD, PDP, LED, FED, a projection screen, and a CRT display.

12-13. -13. (canceled)

15. (canceled)

17. (canceled)

19. (canceled)

21. (canceled)

22. A non-contact type coordinate input method using a non-contact type coordinate input system, the system comprising:

a light guide plate receiving incident light emitted from a light illuminating device, and including a phosphor and at least one optical layer;

a plurality of optical sensors to detect light emitted from the phosphor receiving the light having reached the light guide plate, the optical sensors being attached to one or both of edges in a transverse direction and to one or both of edges in a longitudinal direction of the light guide plate such that a light receiving part of each optical sensor faces an edge side of the light guide plate; and

a calculation unit connected to the optical sensors to calculate a coordinate set at an incident point of light reaching the light guide plate and to deliver the calculated coordinate set to a display device or a computer system connected thereto,

wherein a location of an optical sensor having the highest light-receiving amount among the optical sensors attached to the edges in the transverse direction is calculated as an abscissa of incident light, and a location of an optical sensor having the highest light-receiving amount among the optical sensors attached to the edges in the longitudinal direction is calculated as an ordinate of the incident light.

23. The method according to claim 22, wherein calculation of the location of the optical sensor having the highest light-receiving amount among the optical sensors attached to the edges in the transverse or longitudinal direction is based on regression analysis of a relation between the location of the optical sensor and the light-receiving amount.

24. A Method of inputting coordinates of incident light on a light guide plate for a non-contact type coordinate input system, the light guide plate comprising a phosphor and at least one optical layer, the method comprising:

illuminating incident light to a point of the light guide plate;

allowing light emitted from the phosphor receiving the incident light having reached the light guide plate to reach optical sensors attached to at least two locations on the light guide panel;

detecting intensity of light reaching the optical sensors to output a signal corresponding to the intensity of light;

calculating a distance between each of the optical sensors and an incident point of light by substituting the output signal to a predetermined regression expression representing a relation between intensity of light and a distance; and

obtaining a point coincident to a locus of points where a ratio of distances from the respective optical sensors to the incident point of light or a ratio of distances between two optical sensors is constant, followed by determining a coordinate set of the point as a coordinate set at the incident point of light.

25. The method according to claim 24, wherein, when the system comprises three of more optical sensors, one or more points where loci formed by two pairs of optical sensors meet each other are obtained, and a point corresponding to an average of coordinates sets at the respective points is determined as the point formed by the locus of points where the ratio of distances from the respective optical sensors to the incident point of light is constant.

26. The method according to claim 24, wherein the phosphor is coated on a surface of a transparent layer of the light guide plate or doped into the transparent layer thereof.

28. The method according to claim 24, wherein the light guide plate further comprises a low-refraction layer outside the light guide plate, the low-refraction layer being lower by 0.05 or more in terms of refractive index, as compared with a member having the highest refractive index among members constituting the light guide plate.

30. The method according to claim 24, wherein at least two optical sensors are attached to a front side, a rear side or a lateral side of the light guide plate to detect light emitted from the phosphor receiving the incident light having reached the light guide plate.

31. The method according to claim 24, wherein the incident light is illuminated to the light guide plate in a flickering manner by a flickering light source.

32. The method according to claim 24, wherein the system further comprises a filter between the light guide plate and the optical sensors to absorb light having a wavelength different from that of light emitted from the phosphor.

27. (canceled)

29. (canceled)