Patent ID: 8477577
Filing Date: 2013-07-02
Classification: B82Y,G11B

Abstract:
1. A method for recording information in an optical information recording medium and thereafter reading out the information from the optical information recording medium, which medium comprises: a recording layer having a thickness equal to or greater than 2λ/n, where λ is a wavelength of a recording beam and n is a refractive index of the recording layer, and configured to undergo a change in the refractive index by irradiation with the recording beam; and an adjacent layer disposed adjacent to the recording layer at a side opposite to an incident side from which the recording beam enters the recording layer, the method comprising the steps of: recording a recording spot by irradiating the optical information recording medium with the recording beam, while shifting a focal position by an offset amount d, which satisfies ω reading out the information by irradiating the optical information recording medium with a reading beam, while bringing the reading beam into focus on the interface.