Patent ID: 7403288

Claim:
An apparatus for measuring a thickness of a thin article comprising: an optical fiber interferometer, the optical fiber interferometer being configured for obtaining an optical distance difference caused by the thickness of the thin article, the optical distance difference between a first optical path in which the thin article is measured and a second optical path, the optical fiber interferometer comprising: a laser light source adapted for providing a light beam to the optical coupler; an optical coupler configured for splitting the light beam into a first light and a second light; a first optical fiber coupled to the optical coupler, the first optical fiber being configured for transmitting the first light; and a second optical fiber coupled to the optical coupler, the first optical fiber being configured for transmitting the second light; a first optical collimator coupled with the first optical fiber, the first optical collimator being configured for collimating the first light; a second optical collimator coupled with the second optical fiber, the second optical collimator being configured for collimating the second light; a signal processor module configured for detecting the optical distance difference, and for processing the optical distance difference to obtain a linear signal, the linear signal being convertible into a thickness value of the thin article; and a measuring module including a reference plane and an adjustable plane on which the first optical collimator and the second optical collimator are settled, the thin article begin arranged on the reference place, and the adjustable plane being configured for modulating the first light and the second light to be coherent in phase.