Diffusive-sheetless Backlight for Mobile Phone

Recently, due to need of the mobile phones to be more portable, there is strong expectation of backlight system for that application to be thinner and lighter along with the need to be brighter. To achieve this, we developed a sheetless backlight system that does not require the optical sheets that are usually required. Conventional backlight systems require a diffusive sheet and prism sheets to improve the uniformity and brightness respectively of the light emitted from the lightguide. The functions of these sheets were integrated onto a lightguide and the number of backlight components was reduced by 50%. We describe the method used to integrate the diffusive sheets' functions with the design of the prisms' random arrangement using prism size control.