| 摘要 |
An optical information recording/reproducing apparatus records information on an optical information recording medium and/or reproduces the recorded information by irradiating a plurality of light spots on the recording medium. The apparatus includes a first light source for emitting a light beam with a wavelength lambda 1, and a second light source for emitting a light beam with a wavelength lambda 2. A light spot forming unit focuses the light beam with the wavelength lambda 1 and the light beam with the wavelength lambda 2 through an objective lens, and forms first and second light spots on the information recording medium. The following relations are substantially established: 1>/=D1/W1 ORTHOGONAL >/=0.6; 3.2-2.6x1n alpha >/=D2/W2 ORTHOGONAL >/=1.0-1.2x1n alpha ; and alpha =( lambda 2/ lambda 1)x(D1/D2). D1 is the diameter of the light beam with the wavelength lambda 1 which is incident on the objective lens for formation of the first light spot. D2 is the diameter of the light beam with the wavelength lambda 2 which is incident on the objective lens for formation of the second light spot. W1 ORTHOGONAL and W2 ORTHOGONAL are the diameters, in a direction corresponding to a track crossing direction of the information recording medium, of the light beams with the wavelengths lambda 1 and lambda 2, respectively, incident on the objective lens and forming the first and second light spots, respectively, which corresponds to 1/e2 a peak intensity of the light beam.
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