Optical touch module

1. An optical touch module used in a flat display, comprising:

a transparent substrate, comprising:

a touch surface and a sub-surface parallel to the touch surface; and

a surrounding side surface connected to the touch surface and the sub-surface; and

two light processing units positioned on two neighboring corners of the transparent substrate, wherein each light processing unit has a light source and a detector respectively having a light emitting surface and a light entry surface, the light emitting surface of the light source and the light entry surface of the detector both face the surrounding side surface, and each light processing unit is positioned beneath the touch surface,

wherein, each of the two corners comprises:

a chamfer surface whose one side is connected to the touch surface, wherein the chamfer surface is perpendicular to the touch surface; and

a sloping surface whose one side is connected to the other side of the chamfer surface and the other side is connected to the sub-surface, wherein an inclination angle is formed between the sloping surface and the sub-surface and corresponds to the total reflection critical angle of the transparent substrate.

2. The optical touch module according to claim 1 , wherein:

the surrounding side surface respectively corresponds to two corner angles at each of the two corners;

each of the two corner angles is connected between the touch surface and the sub-surface; and

wherein the light entry surfaces of the two detectors respectively face the chamfer surfaces of the two corner angles;

and the light emitting surfaces of the two light sources respectively face the sloping surfaces of the two corner angles.

3. The optical touch module according to claim 1 , wherein the surrounding side surface comprises:

a first side surface and a second side surface perpendicular to each and adjacent to a first corner of the two corners, wherein the second side surface comprises a first reflection structure;

a third side surface opposite and parallel to the first side surface and adjacent to the second side surface, wherein the third side surface comprises a second reflection structure; and

a fourth side surface opposite and parallel to the second side surface and adjacent to the third and the first side surfaces, wherein the fourth side surface comprises a third reflection structure;

wherein, the first and the fourth side surfaces are adjacent to a second corner of the two corners.

4. The optical touch module according to claim 3 , wherein each of the first, the second and the third reflection structures has a micro-prism structure for partly reflecting light transmitted to the second, the third and the fourth side surfaces.

5. The optical touch module according to claim 3 , wherein each of the first, the second and the third reflection structures has a roughened surface structure partly reflecting light transmitted to the second, the third and the fourth side surfaces.

6. The optical touch module according to claim 1 , wherein

the light sources of the two light processing units respectively project a first light and a second light to the transparent substrate via the corresponding light emitting surfaces, such that the first and the second lights are transmitted in the transparent substrate through total reflection; and

when a touch event is triggered at a touch position on the touch surface, the total reflection of the first and the second lights at the touch position are correspondingly interrupted, such that the first and the second lights correspondingly form a brightness distribution on the surrounding side surface.

7. The optical touch module according to claim 6 , wherein the detectors of the two light processing units respectively detect the brightness distribution via the corresponding light entry surfaces, and correspondingly output a first brightness detection signal and a second brightness detection signal respectively.

8. The optical touch module according to claim 7 , further comprising:

a processor coupled to the two light processing units, wherein the processor determines relative position information of the touch position in response to the first and the second brightness detection signals.

9. The optical touch module according to claim 1 , further comprising at least one detection unit disposed at least one of two other corners of the transparent substrate.

10. The optical touch module according to claim 9 , wherein at least one of the two other corners comprises a corner angle, the detection unit is positioned at the corner angle and beneath the touch surface, the corner angle comprises a chamfer surface whose one side is connected to the touch surface, and the other side opposite to the touch surface is connected to the sub-surface, the chamfer surface is perpendicular to the touch surface, and the light entry surface of each detection unit faces respective chamfer surface.