Optical disk apparatus for optically recording or reproducing information on an optical recording medium

An optical disk apparatus for reproducing information recorded on a recording track of an optical recording medium comprising:

• a light source means for emitting a laser beam in a first direction;
• a beam splitting means located adjacent to said laser source means for splitting said emitted light into first, second, and third laser beams having diffraction orders of +1, 0 and -1, respectively;
• a converging means located between said optical recording medium and said beam splitting means for converging said second laser beam on said recording track and said first and third laser beams around and opposite sides of said recording track;
• a beam guide means located in paths of reflected laser beams from said optical recording medium in a second direction;
• a first photodetection means inserted in a path of said guided second laser beam reflected from said recording track passing through said converging means and said beam guide means, said first photodetection means receiving said second laser beam for producing focus signal and producing information signals representing said information recorded on said recording track based on said received reflected second laser beam, said first photodetection means formed by dividing a photoelectric element into four portions vertically and into two portions horizontally such that eight segments of said divided photoelectric element are arranged in a matrix, said matrix is formed in a rectangular shape, each of said segments producing an electric signal based on said reflected second laser beam received thereon;
• second photodetection means inserted in paths of said first and third laser beams reflected from portions around opposite sides of said recording track, respectively, for producing tracking signals;
• and
• signal reproduction means connected with said first photodetection means for reproducing a record signal recorded on said recording track based on said information signals, said signal reproduction means comprising:
• (a) a first addition means for adding signals produced by four of said segments arranged in vertical opposite side end portions of said matrix to produce a first added signal;
• (b) a second addition means for adding signals produced by four of said segments arranged in vertical center portions of said matrix to produce a second added signal;
• (c) a multiplier means for multiplying said second added signal by a predetermined value to produce a multiplied signal;
• and
• (d) a third addition means for adding said first added signal and said multiplied signal to produce said record signal.