METHOD FOR MEASURING THE THICKNESS OF AN OPTICAL DISK, ESPECIALLY CONCERNED WITH MEASURING A DISK THICKNESS WITH HIGH PRECISION WHILE MAINTAINING A FAST ANALYSIS SPEED, THEREBY IMPROVING DEVICE RELIABILITY

摘要

PURPOSE: A method for measuring thickness of an optical disk is provided to realize a fast analysis speed and a high-precision thickness measurement through a position of a peak value of a reflected light on an interference space obtained by an FFT process for a spectrum which reflects a refractive index as a wavelength function. CONSTITUTION: A measuring device measures the intensity of a reflected light, and detects the measured intensity as wavelength spectrum data(S10). The measuring device converts the detected wavelength spectrum data into spectrum data which reflects a refractive index as a wavelength function(S20). The measuring device converts the converted data into an interference space length showing the thickness of an optical disk through an FFT process, and detects thicknesses of a spacer layer and a cover layer(S30).