| 摘要 |
PURPOSE:To adjust properly an angle of vertical diffusion by combining a lens sheet which has a circular Fresnel lens on an incidence surface and a lenticular lens (LL) on the other surface with a lens sheet which has LLs on both surfaces at right angles to the LL of the former lens sheet. CONSTITUTION:The 1st lens sheet A is provided with the circular Fresnel lens 11 on the incidence side and with the lenticular lens (LL) 12 on the other surface; and the LLs 13 and 15 perpendicular to the LL12 are provided on both surfaces of the 2nd lens sheet B in parallel and a light shield layer 14 is provided to the projection-side nonconverging layer of the sheet B. Incident light is converged by the Fresnel lens 11; the angle of vertical diffusion is determined by the LL12 and an angle of vertical diffusion is determined by the LLs 13 and 15. Further, the light shield layer 14 prevent the unnecessary reflection of stray light and the external light in the lens sheets A and B. |
