Patent attributes
The optical lens system for forming a subject image on a photoelectric conversion section of a solid image pickup element and an image pickup lens includes, in order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, and a fifth lens. The first lens has a positive refractive power and a convex surface on an object side thereof. The second lens has a negative refractive power with a concave surface on an image side thereof. The third lens has a refractive power with an aspheric surface on an object side thereof and a convex surface on an image side thereof. The fourth lens has a positive refractive power with a flat surface on an object side thereof and a convex surface on an image side thereof. The fifth lens has a negative refractive power with aspheric surfaces on an object side and an image side thereof respectively, wherein the fifth lens has at least one inflection point formed at at least one of the aspheric surfaces of the object side and the image side. An aperture stop is disposed at the object side of the first lens and at least one flat element is located between the fifth lens and an image plane.
