Patent ID: 6411591
Filing Date: 2002-06-25
Classification: B82Y,G11B

Abstract:
An optical recording medium that enables at least information to be read out by irradiation of a light, comprising:a mask layer containing at least one of elements in groups Ib, IIb, VIa and VIII in 10 to 40 atomic percent and also containing oxygen; wherein when a read operation is performed at a reading laser power of mW by using a lens with a predetermined wavelength and a predetermined numerical aperture and with a light spot focused to nearly a diffraction limit, a difference between an amount of reflected light from recording marks and an amount of reflected light from spaces between the recording marks is no greater than 25 with the amount of reflected light from the spaces taken as 100, and there is a laser power in a reading laser power range of 2 to 4 mW that causes a difference between an amount of reflected light from spaces between the recording marks to be at least 30 with the amount of reflected light from the spaces taken as 100.