| 摘要 |
A contactless thickness measuring apparatus for measuring the thickness of an object includes a light source emitting a variable-frequency light beam, an oscillating center wavelength of which is changeable; an optical device for illuminating the object with the light beam to measure the thickness of the object; a light intensity detecting device for detecting the intensity of light deflected from the object and of light penetrating through the object; a signal processing device for changing the oscillating center wavelength while monitoring the light intensity and containing an amount of phase change from a waveform of a change in light intensity; and an analyzing device for determining an absolute thickness of the object from a relationship between absolute thickness and a phase change amount. In this way, it is possible to measure the absolute thickness of the object without contact using an apparatus having a simple structure by monitoring the object's thickness during its manufacturing process. Furthermore, the apparatus is relatively insensitive to external influences.
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