Patent ID: 6897911

Claim:
A light diffusing plate comprising: a lens substrate; a plurality of microlenses disposed on a surface of said lens substrate, into which collimated light is launched; a plurality of light exit areas disposed on another surface of said lens substrate, from which diffused light is issued, each having a circular form a center of which is coincident with an optical axis of each of said plurality of microlenses; a light shield layer formed on said another surface of the lens substrate reverse to said plurality of microlenses, and covering an area other than said plurality of light exit areas; and an anti-reflective layer formed on a surface of said light shield layer other than a surface formed on said light shield layer and covering the area other than said plurality of light exit areas wherein when a refractive index of said lens substrate is represented by n; a thickness of said lens substrate by t; a diameter of each of said plurality of light exit areas by R; and a size of each of said plurality of microlenses by Sr, the following formula is satisfied: Sr ≧2 t ×tan θ+ R (with the proviso that θ=sin −1 (1 /n )).