Patent ID: 7705868

Claim:
A light source unit, comprising: a light emitting array comprising a plurality of light emitting elements, said plurality of light emitting elements being formed in line; a transparent thin film layer, said transparent thin film layer being formed on said light emitting array by laminating a material substantially transparent at an emission wavelength of said plurality of light emitting elements; a plurality of microlenses, said plurality of microlenses being formed on said transparent thin film layer to be in one-to-one correspondence to said plurality of light emitting elements; and a microlens of said plurality of microlenses configured to have a radiation angle of a light beam from a corresponding light emitting element of said plurality of light emitting elements passing through said microlens, said radiation angle having a value of at least 20 degrees, wherein said light source unit is formed so as to satisfy relational expressions, including T 1 ≦2 ·D 2 and θ A ≥ 2 · tan - 1 ⁡ ( P T ⁢ 1 - R 2 - ( D ⁢ ⁢ 2 / 2 ) 2 ) , where T 1 is a thickness of said transparent thin film layer, D 2 is a diameter of each of said plurality of microlenses, P is a length of an alignment pitch between adjacent light emitting elements of said plurality of light emitting elements, R is a curvature radius of each of said plurality of microlenses, and θ A is an angle between centers of curvature of adjacent microlenses of said plurality of microlenses as measured from a light emitting element of said plurality of light emitting elements corresponding to one of said adjacent microlenses.