IMAGING OPTICAL SYSTEM AND ELECTRONIC APPARATUS USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide an imaging optical system which simultaneously satisfies lowering of the cost, widening of the angle of view, heightening of the performance and making the size smaller. SOLUTION: The imaging optical system is constituted by arranging, successively from an object side, a positive meniscus lens L 1, as a first lens, which turns its convex face to the object side, a brightness stop S, a negative meniscus lens L 2, as a second lens, which turns its concave face to the object side, and a positive lens L 3, as a third lens, which turns its convex face to an image side, a positive lens L 4, as a fourth lens, having convex faces on both surfaces. The fourth lens L 4 has at least one aspherical surface. The system satisfies the following conditions: 1.0<ψm/ψp<50.0, provided thatψm is the power of the lens in the position of the maximum ray height andψp is the paraxial power of the lens. Also, the system satisfies the following conditions: 0.3