Apparatus for inspecting both sides of tape or sheet

摘要

An apparatus for inspecting the top and bottom surfaces of a tape or sheet has a device to magnify the surface of the tape or sheet, with its objective lens disposed to face the top surface of the tape or sheet. The apparatus also has an optical transmittion system that transmits an image of the bottom surface of the tape or sheet through a focusing unit and four reflectors, each of which is adapted to bend the path of light rays 90 degrees. Of the four reflectors, one that faces the objective lens is retractable from the light-ray path in the optical transmission system. The reflector facing the objective lens may be a half-coated mirror. Fixed in the light-ray path in the optical transmission system, the half-coated mirror is not retractable.