Patent ID: 7095701

Claim:
A method for adjusting an aberration in an optical disc device on which can be selectively loaded a first optical disc having a first index of double refraction or a second optical disc having a second index of refraction larger than said first index of double refraction, and which includes a liquid crystal device between a light source and an objective lens converging a light beam radiated from said light source on the optical disc loaded on said optical disc device, said method comprising: an optimizing step of optimizing a focusing bias if the loaded optical disc is the first optical disc; a step of storing a value of the focusing bias optimized at said optimizing step; a first adjustment step of adjusting a voltage applied to said liquid crystal device so that the phase difference between a polarized light component along the arraying direction of said liquid crystal device and another polarized light component along a direction perpendicular to said arraying direction of said liquid crystal device will be approximately λ/2, where λ is the wavelength; a step of storing the voltage adjusted in said first adjustment step as a reference voltage in a memory; a second adjustment step of adjusting the voltage applied to said liquid crystal device so as to correct a coma aberration based on said reference voltage; and a step of storing the voltage adjusted at said second adjustment step in the memory as a coma aberration correcting voltage.