Patent ID: 7030988

Claim:
A measuring apparatus comprising: a plurality of measuring units comprising a dielectric block, a thin film layer formed on a surface of said dielectric block, and a sample holding mechanism for holding a sample on a surface of said thin film layer; a supporting body for supporting said plurality of measuring units; a light source for emitting a light beam; an optical incidence system for making said light beam enter said dielectric block at an angle of incidence so that a total internal reflection condition is satisfied at an interface between said dielectric block and said thin film layer; photodetection means for measuring the intensity of said light beam totally reflected at said interface; and a drive means for selectively positioning each measuring unit in either a measuring position where said light beam enters the dielectric blocks thereof, or a standby position where no light enters therein, by relatively moving said support body and said optical system as well as said photodetection means; wherein said optical system is constructed so that light beams simultaneously enter the dielectric blocks of at least two measuring units supported by said supporting body; and wherein said photodetection means comprises at least two photodetectors provided so that they correspond in number to the light beams which enter said dielectric blocks.