Patent ID: 7144153

Claim:
A measuring apparatus comprising a sensor unit comprising a dielectric block, a thin film layer which is formed on the upper surface of the dielectric block, and a sample holding portion which holds a sample on the thin film layers a light source emitting a light beam, a sensor holding means which demountably holds the sensor unit in a predetermined position, a light beam projecting means which causes the light beam to enter the dielectric block to impinge upon the interface between the upper surface of the dielectric block and the thin film layer so that total internal reflection conditions are satisfied at the interface, a measuring means provided with a refractive index information obtaining means which obtains refractive index information on analyte on the thin film layer on the basis of the light beam reflected at the interface, a measuring system which accommodates the measuring means, a temperature measuring means which measures the temperature of the measuring system, a constant temperature system which is controlled to be at a predetermined temperature and stores the sensor unit, a conveyor means which selectively positions the sensor unit in a predetermined position in the measuring system or in the constant temperature system, and a controlling means which controls the measuring means and the conveyor means, wherein the improvement comprises that the controlling means estimates temperature change of the sensor unit after it is conveyed to the measuring system from the constant temperature system on the basis of the temperature difference between the predetermined temperature and the measured temperature of the measuring system as measured by the temperature measuring means, and drives the conveyor means to convey the sensor unit to the measuring system and the measuring means to perform the measurement within a time for which the temperature of the sensor unit does not change from the predetermined temperature by a temperature range which is larger than an acceptable temperature range.