OPTICAL SYSTEM, IMAGE PICKUP DEVICE AND OPTICAL LOW-PASS FILTER

摘要

PROBLEM TO BE SOLVED: To provide an optical system, an image pickup device and an optical low-pass filter which satisfactorily suppress the generation of stripe shadow on an imaged picture and adequately prevent the deterioration of picture quality. SOLUTION: This image pickup device 1 is provided with a lens system 2 to which the light C of object to be picked up from the object W is made incident and the low-pass filter 3 and an image pickup part 4 which are successively arranged in the subsequent steps. The low-pass filter 3 is composed of resin members, contains dyestuffs which reveals an ND characteristic and a light control characteristic and is provided with a phase lattice which exhibits the optical low-pass function. In addition, the concentration of dyestuffs in the low-pass filter 3 is set to be such a concentration that the light C of object to be picked up is weakened therein so as to properly expose the image pickup part 4 in the state that the opening diameter of diaphragm 5 is made larger than the twice of lattice period of the phase lattice.