Patent ID: RE40133

Claim:
An optical recording/reproducing apparatus for recording, reproducing or erasing an information signal by converging a light flux onto/from a recording layer through a transparent disc substrate, comprising: (a) N optical heads, N being greater than or equal to 2, each comprising: light emitting means, objective lenses, whose aberrations have respectively been corrected for said N disc substrates having different thicknesses, each for converging the light flux which is emitted from the light emitting means onto the optical disc, and a plurality of photo detecting means each for detecting the reflected light from the optical disc; (b) N optical head moving means which are arranged below the optical disc and move the N optical heads in the radial direction of the optical disc; (c) disc discriminating means for discriminating the thickness of the disc substrate of the loaded optical disc and for generating a discrimination signal in accordance with the result of the discrimination; and (d) control means for selecting the optical head having the objective lens in which the occurrence of the aberration due to the disc substrate is smallest in accordance with the discrimination signal, wherein the selected optical head records, reproduces or erases the information signal onto/from the optical disc.