Patent ID: 7812955

Claim:
A sample analysis apparatus, comprising: i) a light beam irradiating optical system associated with a dielectric material member having a surface, on which a thin film layer has been formed, a sample being capable of being brought into contact with a surface of the thin film layer, the light beam irradiating optical system producing a light beam and irradiating the light beam to an interface between the dielectric material member and the thin film layer in a first state, in which the sample is absent on the surface of the thin film layer, and irradiating the light beam to the interface between the dielectric material member and the thin film layer in a second state, in which the sample has been brought into contact with the surface of the thin film layer, the light beam, which is produced by the light beam irradiating optical system, being constituted of light beam components, which have various different incidence angles with respect to the interface between the dielectric material member and the thin film layer, and which have intensities varying in accordance with the incidence angles with respect to the interface; ii) a single measuring detector for outputting a first measurement signal, which represents an intensity of an entire area of light irradiated in the first state received by the measuring detector and for outputting a second measurement signal, which represents an intensity of an entire area of the light irradiated in the second state received by the measuring detector, the measuring detector being secured and located such that the measuring detector is capable of receiving the light beam, which has been reflected from the interface between the dielectric material member and the thin film layer; and iii) a calculating means for calculating an incidence angle of a light beam component among the light beam components constituting the light beam, which light beam component has been subjected to attenuated total reflection, in accordance with a value of a difference signal representing a difference between the first measurement signal and the second measurement signal, the thus specified incidence angle being taken as the attenuated total reflection angle of the sample.