Patent ID: 8641253

Claim:
A light guide device, comprising: a body having an emitting surface, a reflective surface and an incident surface, the reflective surface and the emitting surface being correspondingly disposed on the light guide device, the incident surface being connected to a side of the reflective surface and the emitting surface; pluralities of first microstructures disposed on the reflective surface, each first microstructure has a first point and a second point defined in cross section wherein the same first microstructure connects to the reflective surface by means of the first point and the second point, the corresponding first point and second point being disposed at two ends of the first microstructure with a first width (P 1 ); pluralities of flat portions wherein each flat portion is disposed between two adjacent first microstructures and has a gap (G) defined between the same two first microstructures; pluralities of second microstructures wherein each second microstructure has a base portion and two edge portions defined in cross section, two ends of the base portion being respectively tangent to two edge portion, the second microstructure connecting to the incident surface by means of two edge portions, the corresponding two edge portions having a second width (P 2 ) defined on the incident surface; wherein a first depth (H 1 ) is defined to be the distance between the crossing point of two edge portions away from the incident surface; pluralities of diffusive beads which have weight M b spreading inside the body which has weight M t , wherein the equations of H 1 P 2 * P 1 G ≤ 0.288 ⁢ ⁢ and ⁢ ⁢ H 1 P 2 * P 1 G * M t M b ≤ 96.0 are satisfied.