Optical disk device for record and reproduction of additional information besides reproducing of basic information

Claim 1

An optical disk device for reproducing and recording information comprising: an optical disk including a substrate disk having a surface formed with a series of pits and lands along a basic recording track for recording basic information including address information and data information, and an additional recording layer formed on said surface and said substrate disk for recording additional information along an additional recording track, positioned above said basic recording track, in an additional form different from said series of pits and lands; an optical head for irradiating an optical beam to said optical disk along said basic recording track and for receiving a reflected beam reflected from said optical disk to produce a reading signal including a basic information signal representative of a beam intensity of said reflected beam varied by said series of pits and lands and an additional information signal by detecting said additional form in said reflected beam; a basic information reproducing circuit connected to said optical head via switching means for reproducing said basic information in response to said basic information signal; an additional information recording and reproducing circuit connected to said optical head via said switching means for causing said optical head to record said additional information along said additional recording track by means of said optical beam in said additional form so as to add said additional information to said basic information, and for reproducing said additional information in response to said additional information signal; and control means for causing said switching means to connect said optical head to one of said basic information reproducing circuit and said additional information recording and reproducing circuit.