Light guide module, optical touch module, and method of increasing a signal to noise ratio of an optical touch module

• US 20100214270A1
• Filed: 03/08/2010
• Published: 08/26/2010
• Est. Priority Date: 02/25/2009
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Lai, Hung-Ching, Chuang, Chiang-Yuan, Chen, Hui-Hsuan
• Granted Patent: US 8,854,336 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• 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 light guide module is applied in an optical touch module. A focusing component of the light guide module focuses the light emitted from a light guide component of the light guide module, so that all the light emitted from the light guide component can be convergently distributed in a touch area of the optical touch module. In this way, the light provided by a lighting component of the optical touch module can be effectively utilized, and the signal to noise ratio of the received signal of a sensor of the optical touch module increases. Therefore, the optical touch module can determines the location of the finger or the contacting object more correctly.

Claims

1. A light guide module, applied in an optical touch module, the optical touch module having a touch area, a sensor, and a lighting component, the sensor located on a first corner of the touch area, the lighting component utilized for providing a light, the light guide module and the lighting component disposed on a first side of the touch area for evenly distributing the light provided by the lighting component to the touch area, the light guide module comprising:

a light guide component, for guiding the light to diffuse along the light guide component, comprising;

a light-receiving surface, facing the lighting component for receiving the light; and

a light-emitting surface, facing the touch area; and

a focusing component, for focusing the light emitted from the light-emitting surface so as to urge the light evenly distributed in the touch area.

2. The light guide module of claim 1, wherein the light guide component further comprises:

a light guider, a first surface of the light guider utilized as the light-receiving surface, a second surface of the light guider utilized as the light-emitting surface; and

a reflecting component, covering the light guider, for reflecting the light not emitted from the light-emitting surface out of the light guide component back to the light guider, so that the light guided by the light guide component enters the touch area only through the light-emitting surface.

3. The light guide module of claim 1, wherein the lighting component is an infrared Light-Emitting Diode (LED), and the focusing component is transparent to infrared light.

4. The light guide module of claim 1, wherein the light guide module further comprises a holder for covering the light guide component so as to fix the light guide module on a substrate.

5. The light guide module of claim 4, wherein the substrate is an Indium Tin Oxide (ITO) glass.

6. The light guide module of claim 4, wherein the lighting component is at a second corner of a second side of the optical touch module;

the first side is opposite to the second side.

7. The light guide module of claim 6, wherein the light guide module further comprises a direction-changing structure;

the direction-changing structure is utilized for turning the light-receiving surface to face the substrate, and turning received light of the light-receiving surface to be parallel to the substrate;

the lighting component is disposed on the substrate and the lighting component emits lights to the light-receiving surface.

8. The light guide module of claim 1, wherein the focusing component is a convex-concave lens, a convex-flat lens, a convex-convex lens, or a flat-concave lens.

9. The light guide module of claim 8, wherein when the focusing component is a convex-concave lens, a convex surface of the convex-concave lens faces the light-emitting face, and a concave surface of the convex-concave lens faces the touch area;

when the focusing component is a convex-flat lens, a convex surface of the convex-flat lens faces the light-emitting face, and a flat surface of the convex-flat lens faces the touch area;

when the focusing component is a flat-concave lens, a flat surface of the flat-concave lens faces the light-emitting face, and a concave surface of the flat-concave lens faces the touch area.

10. The light guide module of claim 1, wherein the light guide component further comprises a reflecting surface;

the reflecting surface is located at a bending location of the light guide component for reflecting the light so as to keep the light transmitted in the light guide component, and avoiding the light emitted out from the bending location of the light guide component.

11. An optical touch module, comprising:

a touch area;

a sensor, located at a first corner of the touch area;

a lighting component, disposed on a first side of the touch area for providing a light; and

a light guide module, disposed on the first side of the touch area for evenly distributing the light provided by the lighting component to the touch area, the light guide module comprising;

a light guide component, for guiding the light to diffuse along the light guide component, comprising;

a light-receiving surface, facing the lighting component for receiving the light; and

a light-emitting surface, facing the touch area; and

a focusing component, for focusing the light emitted from the light-emitting surface so as to urge the light evenly distributed in the touch area.

12. The optical touch module of claim 11, wherein the light guide component further comprises:

a light guider, a first surface of the light guider utilized as the light-receiving surface, a second surface of the light guider utilized as the light-emitting surface; and

a reflecting component, covering the light guider, for reflecting the light not emitted from the light-emitting surface out of the light guide component back to the light guider, so that the light guided by the light guide component enter the touch area only through the light-emitting surface.

13. The optical touch module of claim 11, wherein the lighting component is an infrared Light-Emitting Diode (LED), and the focusing component is transparent to infrared light.

14. The optical touch module of claim 11, wherein the light guide module further comprises a holder for covering the light guide component so as to fix the light guide module on a substrate.

15. The optical touch module of claim 14, wherein the substrate is an ITO glass.

16. The optical touch module of claim 14, wherein the lighting component is at a second corner of a second side of the optical touch module;

the first side is opposite to the second side.

17. The optical touch module of claim 16, wherein the light guide module further comprises a direction-changing structure;

the direction-changing structure is utilized for turning the light-receiving surface to face the substrate, and turning received light of the light-receiving surface to be parallel to the substrate;

the lighting component is disposed on the substrate and the lighting component emits lights to the light-receiving surface.

18. The optical touch module of claim 11, wherein the focusing component is a convex-concave lens, a convex-flat lens, a convex-convex lens, or a flat-concave lens.

19. The optical touch module of claim 18, wherein when the focusing component is a convex-concave lens, a convex surface of the convex-concave lens faces the light-emitting face, and a concave surface of the convex-concave lens faces the touch area;

when the focusing component is a convex-flat lens, a convex surface of the convex-flat lens faces the light-emitting face, and a flat surface of the convex-flat lens faces the touch area;

when the focusing component is a flat-concave lens, a flat surface of the flat-concave lens faces the light-emitting face, and a concave surface of the flat-concave lens faces the touch area.

20. The optical touch module of claim 11, wherein the light guide component further comprises a reflecting surface;

the reflecting surface is located at a bending location of the light guide component for reflecting the light so as to keep the light transmitted in the light guide component, and avoiding the light emitted out from the bending location of the light guide component.

21. A method of increasing a signal-to-noise ratio of an optical touch module, the optical touch module having a touch area, a sensor, a lighting component, and a light guide component, the sensor located at a first corner of the touch area, the lighting component utilized for providing a light, the light guide component utilized for guiding the light to diffuse along the light guide component, the light guide component comprising a light-receiving surface and a light-emitting surface, the light-receiving surface facing the lighting component for receiving the light, the light-emitting surface facing the touch area, the method comprising:

disposing a focusing component in front of the light-emitting surface of the light guide component; and

the focusing component focusing the light emitted from the light-emitting surface so as to urge the light convergently distributed in the touch area, increasing the signal-to-noise ratio of the optical touch module.

22. The method of claim 21, wherein the lighting component is an infrared Light-Emitting Diode (LED), and the focusing component is transparent to infrared light.

23. The method of claim 21, wherein the focusing component is a convex-concave lens, a convex-flat lens, a convex-convex lens, or a flat-concave lens.

24. The method of claim 23, wherein disposing the focusing component in front of the light-emitting surface of the light guide component comprises:

when the focusing component is a convex-concave lens, disposing a convex surface of the convex-concave lens to face the light-emitting face, and disposing a concave surface of the convex-concave lens to face the touch area.

25. The method of claim 23, wherein disposing the focusing component in front of the light-emitting surface of the light guide component comprises:

when the focusing component is a convex-flat lens, disposing a convex surface of the convex-flat lens to face the light-emitting face, and disposing a flat surface of the convex-flat lens to face the touch area.

26. The method of claim 23, wherein disposing the focusing component in front of the light-emitting surface of the light guide component comprises:

when the focusing component is a flat-concave lens, disposing a flat surface of the flat-concave lens faces the light-emitting face, and disposing a concave surface of the flat-concave lens faces the touch area.