SUBMINIATURE OPTICAL SYSTEM

摘要

A micro image pickup optical system is provided to reduce chromatic aberrations by using first and second lenses with big difference in refractive indexes and abbe numbers and to implement a microminiature structure by relatively increasing power of the first and second lenses. A micro image pickup optical system is composed of a first lens(L1) having the positive refractive power and both convex surfaces; a second meniscus lens(L2) having the negative refractive power and convex toward an object; a third meniscus lens(L3) having the positive refractive power and convex toward an image; and a fourth lens(L4) having the negative refractive power. The dimension of an optical axial direction of the micro image pickup optical system satisfies the following formula 1, 1.2<TL/f<1.3 and power of the first lens satisfies the following formula 2, 0.6<f1/f<0.8. The TL is a distance from an aperture stop(AS) to an image surface(IP). The f is an effective focal distance of the entire optical system. The f1 is a focal distance of the first lens.