Patent ID: 7006302

Claim:
An image-formation lens system comprising a plurality of lenses with aspheric lenses, wherein: any one of said aspheric lenses has an aspheric surface on an entrance side or an exit side thereof, and satisfies the following conditions: 0.4>(ΔZ max −ΔZ half )/Y max >O.18 (6) 0.05>ΔZ half /Y max ≧O (7) where Y max is a maximum value of a distance of said aspheric lens surface from an optical axis, ΔZ max is an absolute value of a distance from a plane vertical to the optical axis including a lens surface apex at Y max , and ΔZ half is an absolute value of a distance from a plane vertical to the optical axis including a lens surface apex at a half distance of said maximum value Y max , provided that the lens surface refers to an entire area wherein a surface shape inclusive of an effective diameter exists continuously, indicative of a boundary between that area and an area where the surface shape becomes discontinuous.