In the beam optical intensity distribution measuring method which measures the optical intensity distribution

摘要

PROBLEM TO BE SOLVED: To easily and accurately determine distribution of light intensity in the radial direction and diameter of a beam spot which is formed on the recording surface of an optical disk by the laser beam which an optical head irradiates.;SOLUTION: A disk 1 for measurement, in which a spiral groove 2 having the depth of the order of 1/4 of wavelength of the laser beam as the object to be masured, a width larger than an anticipated spot diameter and the interval with the adjacent groove wider than the anticipated spot diameter is formed on the interface with a reflection film 12 of high-transmissive substrate 11 is rotated with a constant linear velocity, the prescribed radial position of the disk 1 for measurement is irradiated with a light beam; and on the basis of the read signal obtained from the reflected light and the spiral shape of the groove 2, the distribution of light intensity in the radial direction and the diameter of the beam spot is found.;COPYRIGHT: (C)2002,JPO