Patent ID: 6031810
Filing Date: 2000-02-29
Classification: G11B

Abstract:
An optical information recording/reproducing apparatus for recording information on an information recording medium and/or reproducing the recorded information by irradiating a plurality of light spots on the optical information recording medium, comprising:a first light source for emitting a first light beam with a wavelength .lambda..sub.1 ;a second light source for emitting a second light beam with a wavelength .lambda..sub.2 ; andlight spot forming means for focusing the first light beam and the second light beam through an objective lens, and forming first and second light spots on said information recording medium, wherein the following relations are substantially established:1.gtoreq.D.sub.1 /W.sub.1.perp. .gtoreq.0.63.2-2.6.times.ln.alpha..gtoreq.D.sub.2 /W.sub.2.perp. .gtoreq.1.0-1.2.times.ln.alpha..alpha.=(.lambda..sub.2 /.lambda..sub.1).times.(D.sub.1 /D.sub.2)where D.sub.1 is a diameter of the first light beam which is incident on said objective lens for formation of the first light spot, D.sub.2 is a diameter of the second light beam which is incident on said objective lens for formation of the second light spot, W.sub.1 .perp. is a diameter of a component, in a direction corresponding to a track crossing direction of said information recording medium, of the first light beam incident on said objective lens and forming the first light spot, the component of the first light beam corresponding to 1/e.sup.2 of a peak intensity of the first light beam, and W.sub.2 .perp. is a diameter of a component, in a direction corresponding to the track crossing direction of said information recording medium, of the second light beam incident on said objective lens and forming the second light spot, the component of the second light beam corresponding to 1/e.sup.2 of a peak intensity of the second light beam.