Land/groove discriminating method and optical recording/reproducing apparatus employing the method

An optical recording and/or reproducing apparatus comprising:

• an optical pickup comprising an optical element on a traveling path of a light beam emitted from a light source to be focused on a land/groove type optical disc by an objective lens, the optical element causing and varying an effect of thickness variation of the optical disc, and a photodetector device to detect the light beam reflected/diffracted by the optical disc by dividing the reflected/diffracted light beam into inner and outer light beam portions;
• and
• a signal processing unit to detect a difference signal by subtracting a detection signal from at least one outer light beam portion from a detection signal from the inner light beam portion and to discriminate between a land and a groove of the optical disc by detecting variation in the difference signal while varying the degree of the effect of thickness variation of the optical disc by driving the optical element.

An optical recording and/or reproducing apparatus comprising:

• an optical pickup comprising an optical element on a traveling path of a light beam emitted from a light source to be focused on a land/groove type optical disc by an objective lens, the optical element causing and varying an effect of thickness variation of the optical disc, and a photodetector device to detect the light beam reflected/diffracted by the optical disc by dividing the reflected/diffracted light beam into inner and outer light beam portions;
• and
• a signal processing unit to detect a difference signal by subtracting a detection signal from at least one outer light beam portion from a detection signal from the inner light beam portion and to compensate for the spherical aberration caused by a thickness variation of the optical disc by detecting variation in the difference signal while varying the degree of the effect of thickness variation of the optical disc by driving the optical element.