OPTICAL DISK

摘要

PURPOSE:To improve a track density without changing the lens and laser of an optical disk memory device by providing a difference in height by as much as the wavelength of 1/4 the laser wavelength and neighbouring value for reproducing or the approximate value thereof on the recording surfaces of adjacent two tracks on both sides of one track. CONSTITUTION:The adjacent tracks TR(n-1) (n+1) are also irradiated with the laser beam LSR and the reflected light ray based thereon are generated if the diameter of the laser beam BM for irradiation is larger than the intertrack spacing of the optical disk 10. The reflected light from the (n-1) track TR of the reflected light rays from the tracks TR(n-1) (n+1) advances in phase nearly by pi/2 and the reflected ligh from the (n+1) track TR delays in phase nearly by pi/2 if the reflected light from the n track is assumed to be a center. The reflected light rays from the (n-1) track TR are, therefore, shifted eventually by nearly pi in phase. These reflected light rays are negated by each other and crosstalks are consequently decreased. The track density is improved in this way without replacing the lens and laser to be used.