Focus control device in optical recording and reproducing apparatus having an optical-beam-position judging device

A focus control device in an optical recording and reproducing apparatus, comprising:

• optical detecting means having a plurality of optical detecting sections for detecting reflected light of an optical beam irradiated to an optical recording medium;
• error-signal generating means for generating a focus error signal on the basis of an output from said optical detecting means;
• focus regulating means for regulating a focusing state on a surface of said optical recording medium of said optical beam on the basis of said focus error signal;
• pseudo-focus-error-signal generating means for generating a pseudo focus error signal of a predetermined level which brings back a focusing point of said optical beam to a control target position;
• optical-beam-position judging means for judging whether or not the focusing point of said optical beam is spaced by a predetermined quantity from said control target position on the basis of outputs from optical detecting sections in said optical detecting means, said outputs from said optical detecting, sections in said optical detecting means being asymmetrical about said control target position;
• and
• error-signal selecting means for selectively switching and outputting one of said focus error signal that is an output from said error-signal generating means and said pseudo focus error signal as an error signal supplied to said focus regulating means in accordance with the shifting quantity of the focusing point of said optical beam from said control target position, on the basis of an output from said optical-beam-position judging means.