Patent ID: 8306643

Claim:
A method for designing a light guide plate, the method comprising the steps of: (a) providing a raw light guide plate having a light input surface and a light output surface; (b) dividing the light output surface of the raw light guide plate into several annuluses, and dividing a region of the light input surface into several annuluses according to the annuluses of the light output surface and an illuminance distribution of the light output surface, wherein the step (b) comprises the step of: (b 1 ) determining the illuminance distribution of the light output surface when there are no scattering dots on the light input surface; (c) determining an effective density of scattering dots for each annulus of the light input surface, the effective density of scattering dots defined as D ⁢ ( ρ , θ ) = S dot S a wherein, D(ρ,θ) is the effective density of scattering dots, S dot is a total area of all the scattering dots in the each annulus, and S a is an area of the each annulus, ρ is a polar radius; and θ is a polar angle, with a center of the light output surface or the light input surface as a pole; and (d) calculating a total number of the scattering dots needed for the each annulus according to the effective density, and generating multiple scattering dot distributions by randomly distributing the calculated total number of the scattering dots on the each annulus of the light input surface; selecting one of the multiple scattering dot distributions with highest illuminance uniformity as a final distribution, whereby a designed light guide plate is obtained.