OPTICAL SYSTEM FOR CAMERA

摘要

PURPOSE: A micro type imaging optical system capable of using the three plastic lenses is provided to maintain the high resolution and enable the miniaturization of the optical system by each lens maintaining a constant thickness. CONSTITUTION: A first lens(L1) has the positive refractive power of a meniscus shape bulged from an object side in an order. A second lens(L2) has the negative refractive power of the meniscus shape bulged to an upper side. A third lens(L3) has a recess shape from an optical axis to the object side, has at least one curve change point in the upper side and has the negative refractive power. A value taking the refractive index at a d line of the second lens out of the refractive index at the d line of the first lens is smaller than 0.08.