SCANNING LENS UNIT AND OPTICAL SCANNING APPARATUS INCLUDING THE SAME

摘要

The scanning lens unit includes lenses located between a optical deflector and a lens having a k-th lens surface S_k from a first lens surface S₁ closest to the deflector are disposed such that a height of a lens having the lens surface S_k denoted by pi_k satisfies the predetermined expression. each of lenses located between the first lens surface S₁ and the k-th lens surface S_k is a cylindrical lens having power only in the determined deflection direction. Therefore, the lenses can individually have minimum thicknesses, as a result, the cost reduction of the scanning lens unit is realized. The optical scanning apparatus includes the scanning lens and hence can achieve cost reduction.