Patent ID: 6496450
Filing Date: 2002-12-17
Classification: G11B

Abstract:
An optical recording/reproducing apparatus accessing a recording layer of an optical rotating recording medium using an accessing means positioned a predetermined gap away from a surface of said optical rotating recording medium and mounted with an object lens, wherein:a thickness of a protective transparent layer of said optical rotating recording medium, a ratio of a defect area with respect to a beam spot area, and the above predetermined gap are values determined by the conditions defined in the following inequalities: G1&leq;t&CenterDot;k&it;â€ƒ&it;Ï€Ã—tan&it;{sin-1&af;(NAn)}â€ƒor t&GreaterEqual;Gk&it;â€ƒ&it;Ï€&CenterDot;tan&it;{sin-1&af;(NAn)}â€ƒwhere, G is a gap separating accessing means from surface of optical rotating recording medium, t is a thickness of transparent layer positioned at surface of recording medium of optical rotating recording medium, n is a refractive index of transparent layer, and NA is a numerical aperture of optical system including object lens.