JPS5713337A - Measuring method for refractive index - Google Patents

Abstract

PURPOSE:To measure refractive index readily, by a method wherein a thin plate wedge-shaped transparent body is mounted on a flat reflecting surface, a white light beam is made incident thereon at a given incident angle, the beam going out therefrom is made incident on a prism again, and the outgoing angle thereof from the prism is measured. CONSTITUTION:A thin plate wedge-shaped transparent body 4 as a body to be measured is mounted on a flat reflecting surface, and a white light beam B is made incident thereon. Said beam is refracted at a refractve angle epsilon1', made incident on the flat reflecting surface at an incident angle epsilon2, reflected at a reflectve angle epsilon2, passed through said body 4 again, and made incident on the surface thereof at an incident angle epsilon3 before going out at a refractive angle epsilon3'. Moreover, said beam is made incident on a prism 3 at an incident angle epsilon4 to travel rectilinearly therethrough at a refractive angle epsilon4' and made incident on the inclined surface of the prism 3 at an incident angle epsilon5 before going out from said inclined surface at refractive angle epsilon5'. By calculating these angles by using the principles of refraction and reflection, the refractive index n of said body 4 can be represented by the ratio between the sines of the incident angle epsilon1 and the refractive angle epsilon1'.