JPS6472032A - Optical density measuring instrument for inspecting image - Google Patents

Abstract

PURPOSE:To eliminate the generation of an unnecessary shadow, and to obtain a measuring instrument which can reach a level of an image inspection executed by a man, by constituting the titled instrument so that a light emitted from a light source projects a measured part of an image from plural directions. CONSTITUTION:An irradiation adjusting part 49 emits a light beam made incident through a light leading tube 48 from a light source containing box 45, so as to irradiate a measured part 53 from plural directions. The incident angle of the light made incident on the measured part 53 is set, for instance, to 45 deg.+ or -5 deg., and the light of equal intensity is made incident from every direction in a shape for forming a conical surface. A reflected light from the measured part 53 is allowed to branch into two directions by a prism 54, and thereafter, one light passes through a measured visual field adjusting mechanism 56, and thereafter, made incident on a photoelectric multiplier 58, from which a data for inspecting an image is obtained. The other light allowed to branch by the prism 54 passes through a roof-shaped prism 64 and forms an image on a observation screen 65, and enlarged and observed by an enlarging eyepiece 42. In this regard, the irradiation adjusting part 49 varies the emitted light quantity in accordance with the light receiving sensitivity of the photoelectric multiplier 58.