Optical information storage medium having lands and grooves both serving as recording tracks

An optical information storage medium having a plurality of grooves and a plurality of lands alternately formed, each of said grooves and each of said lands functioning as recording tracks to form an information storage region, said optical information storage medium comprising:

• a first header region having a plurality of first phase pits respectively formed on extensions of said plurality of lands;
• and
• a second header region having a plurality of second phase pits respectively formed on extensions of said plurality of grooves;
• wherein said first header region and said second header region are shifted from each other along an extension of each of said grooves;
• each of said grooves has an optical depth of (2n+1) λ/8 where A is the wavelength of a light beam to be used and n is a positive integer;
• each of said first phase pits has an optical depth of (2n−1−4m) λ/8 where m is an integer not less than 0;
• each of said second phase pits has an optical depth of (2n+1−4s)λ/8 where s is an integer not less than 0;
• and
• said n, m;
• and s are related so as to satisfy conditions of 2n−1−4m>0 and 2n+1−4s>0.

An optical information storage medium having a plurality of first grooves and a plurality of lands alternately formed, each of said first grooves and each of said lands functioning as recording tracks to form an information storage region, said optical information storage medium comprising:

• a plurality of second grooves respectively formed on extensions of said first grooves so as to continue to said first grooves, each of said second grooves having a width smaller than that of each of said first grooves;
• a groove header region having a plurality of first phase pits respectively formed so as to overlap said plurality of second grooves;
• and
• a land header region having a plurality of second phase pits respectively formed on extensions of said plurality of lands so that each of said second phase pits is interposed between any adjacent ones of said second grooves;
• wherein said groove header region and said land header region are shifted from each other along the extension of each first groove;
• all of said first grooves, said second grooves, and said first phase pits have the same optical depth of about (2n+1)λ/8 where λ is the wavelength of a light beam to be used and n is a positive integer;
• each of said second phase pits has an effective optical depth of about (2m−1)λ/4 where m is a positive integer;
• and
• said n and m are related so as to satisfy a condition of (2m−1)λ/4<(2n+1)λ/8.