Patent ID: 7180686
Filing Date: 2007-02-20
Classification: G02B

Abstract:
1. An image pickup unit for endoscope consisting of an objective optical system and a solid-state image pickup device, and having a maximum field angle of 150° or larger, wherein said objective optical system is composed of spherical lens elements and plane parallel plates, and consists of a first lens unit which comprises a first meniscus lens element having a convex surface on the object side and having negative refractive power and has negative refractive power as a whole, a second lens unit which comprises at least a convex lens element and has positive refractive power as a whole and an aperture stop which is disposed between the first lens unit and the second lens unit, and satisfies the following conditions (1), (2) and (3): wherein a reference symbol f represents a focal length of the objective optical system, a reference symbol IH designates a maximum image height in a display area of the solid-state image pickup device, a reference symbol f