Method of recording and reproducing digital information and apparatus therefor

Claim 2

A digital information recording and reproducing method comprising the steps of: forming a plurality of light beam guide tracks on a recording medium capable of multiple light-wavelength recording, said tracks being spaced apart by a predetermined pitch and each of said tracks comprising a series of pre-pits disposed in a scan direction and spaced apart by an interval longer than the diameter of a spot of a light beam for use in recording and reproducing; and recording and reproducing an information bit by changing said light beam to have a different wavelength predetermined n times in a predetermined order while said light beam is scanned by one interval of said pre-pits.

Claim 3

A method according to claim 1, wherein the timing of said wavelength change is set based on at least one interval of said pre-pits.

Claim 4

A method according to claim 1, wherein said recording medium includes a transparent substrate and a recording film formed on said transparent substrate.

Claim 5

A method according to claim 1, wherein said recording medium includes a transparent substrate, a recording film formed on said transparent substrate, and a reflecting layer formed on said recording film.

Claim 6

A digital information recording and reproducing apparatus comprising: a recording medium capable of multiple light-wavelength recording; a series of pre-pits formed on said recording medium, said series of pre-pits being disposed in a scan direction and spaced apart by an interval longer than the diameter of a spot of a light beam for use in recording and reproducing, and said series of pre-pits being disposed spaced apart by a predetermined pitch substantially perpendicular to said scan direction; laser drive means inputted with a digital recording information signal for driving a semiconductor laser; said semiconductor laser being responsive to the output from said laser drive means for recording a plurality of information bits, corresponding to a predetermined plurality of wavelengths, on said recording medium; drive means for driving said recording medium; light detecting means for detecting a light reflected or transmitted from said recording medium; means including a low-pass filter and a synchro pulse generator for deriving from the output of said light detecting means a synchro pulse signal to be applied to said laser drive means; and a high-pass filter for obtaining a reproduced signal from the output of said light detecting means; wherein said information bits respectively recorded in correspondence with said predetermined plurality of wavelength are disposed in a predetermined order within one interval of said pre-pits.

Claim 7

A digital information recording and reproducing apparatus comprising: a recording medium capable of multiple light-wavelength recording; a series of pre-pits formed on said recording medium, said series of pre-pits being disposed in a scan direction and spaced apart by an interval longer than the diameter of a spot of a light beam for use in recording and reproducing, and said series of pre-pits being disposed spaced apart by a predetermined pitch substantially perpendicular to said scan direction; laser drive means inputted with a digital recording information signal for driving a semiconductor laser; said semiconductor laser being responsive to the output from said laser drive means for recording a plurality of information bits, corresponding to a predetermined plurality of wavelengths, on said recording medium; drive means for driving said recording medium; light detecting means for detecting a light reflected or transmitted from said recording medium; means including a low-pass filter and a synchro pulse generator for deriving from the output of said light detecting means a synchro pulse signal to be applied to said laser drive means; and a high-pass filter for obtaining a reproduced signal from the output of said light detecting means; wherein said information bits respectively recorded in correspondence with said predetermined plurality of wavelength are disposed in a predetermined order within one interval of said pre-pits.

Claim 8

An apparatus according to claim 5, wherein in a plurality of pre-pit trains spaced apart by a pitch, at least one of edges of said pre-pit is aligned on a straight line substantially perpendicular to said scan direction.