Optical disc

Abstract

Abstract PURPOSE:To obtain tracking information without decreasing recording density, by forming a recording medium on rugged grooves of a concentric circle or spiral shape. CONSTITUTION:Concentric circle or spiral rugged grooves are provided on a glass or plastic disc 1 and a recording medium 2 is formed on the rugged parts. The width of the grooves is set to about 90% of the diameter of laser beam for reproduction and the level difference of the grooves is set to 1/8 n(where; n is a refractive index of the disc 1) of the wavelength of the laser beam. An information pit 6 is formed by irradiating the laser beam 7 to a recording track 5 and the tracking is performed by the adjacent rugged grooves.

Inventors

• 👤 Akira Takahashi
• 👤 明 高橋
• 👤 Kenji Oota
• 👤 賢司 太田
• 👤 Hideyoshi Yamaoka
• 👤 山岡　秀嘉

Bibliographic Details