Patent ID: 6922247

Claim:
An automatic optical measurement method including a light projecting portion and a light receiving portion disposed in close adjacency to each other for taking measurement on light projected from the projecting portion onto a sample and thence reflected, wherein a transparent or translucent member is fixed in place between the sample, and the light projecting and receiving portions for reflecting a part of the light projected from the light projecting portion into the light receiving portion, comprising determining a ratio between a measurement of an intensity of light reflected by the transparent or translucent member and a measurement of intensity of light reflected by a reference, by using a measurement of intensity of light reflected from the transparent or translucent member and a measurement of intensity of light taken with the reference set in place and estimating an intensity of light assumed to be obtained if the reference were set in place during a sample measurement, by using a measurement of intensity of light taken from the transparent or translucent member and the ratio thus determined, so as to correct the measurement of intensity of light reflected from the sample.