Light diffusion sheet for back light module and manufacture method thereof

The invention discloses a manufacture method of a light diffusion film for a back light module. The method comprises the following steps of: (1) preparing a fixing layer with stickiness on a side surface of a substrate; (2) distributing and fixing granules in a micro-nano-meter structure size on the surface of the substrate through the fixing layer; (3) using the substrate which is obtained in the step (2) and provided with a surface micro structure as an electroforming template, carrying out precise electroforming, and transferring the micro structure to an electroforming metal sheet; (4) using the metal electroforming sheet obtained in the step (3) as a stamping template, stamping the metal electroforming sheet on a light diffusion sheet material through hot stamping or ultraviolet stamping to obtain the light diffusion sheet. In the method, a micro lens structure is stamped on a transparent substrate by utilizing the micro-nano-meter stamping technology. The method is simple and convenient and rapid, reduces the manufacture cost of the diffusion sheet, is particularly suitable for manufacturing an ultrathin structure, can effectively reduce the thickness of a back light module and has good optical property.