Patent ID: 8226287

Claim:
A light guide plate, capable of guiding a light beam emitted by at least one light emitting device, the light guide plate comprising: a light-transmissive substrate, having a first surface, a second surface opposite to the first surface, and an incident surface connecting the first surface and the second surface, wherein the light beam from the light emitting device is capable of entering the light-transmissive substrate through the incident surface and is capable of being emitted out of the light-transmissive substrate through the first surface; and a plurality of optical structures, disposed on the second surface, each of the optical structures having a first total internal reflection (TIR) surface, a second TIR surface, and a third TIR surface, wherein the second TIR surface connects the first TIR surface and the third TIR surface, a first normal vector of the first TIR surface passing through a geometric center of the first TIR surface forms an angle θ 1 with the second surface, a second normal vector of the second TIR surface passing through a geometric center of the second TIR surface forms an angle θ 2 with the second surface, and a third normal vector of the third TIR surface passing through a geometric center of the third TIR surface forms an angle θ 3 with the second surface, wherein the first TIR surface meets 25°≦θ1≦<65°, the second TIR surface meets 25°≦θ2≦65°, and the third TIR surface meets 25°≦θ3≦65°, an orthogonal projection vector of the first normal vector on the second surface forms an angle φ 1 with an orthogonal projection vector of the second normal vector on the second surface, and the orthogonal projection vector of the second normal vector on the second surface forms an angle φ 2 with an orthogonal projection vector of the third normal vector on the second surface, wherein the first TIR surface and the second TIR surface meet 0<φ1≦30°, and the second TIR surface and the third TIR surface meet 0<φ2≦30°, wherein a part of the light beam from the incident surface is capable of being totally internally reflected by any adjacent two of the first TIR surface, the second TIR surface, and the third TIR surface in sequence.