Optical disc

Abstract

Abstract PURPOSE:To reduce an optical refractive index and to prevent reflective noise from a base plate, by using the base plate having an alumina layer to produce an optical disc. CONSTITUTION:The optical disc uses the base plate obtained by forming an alumina layer on a disc consisting of Al or alloy including Al and the optical reflectance is reduced by forming the alloy disc obtained by alloying one or two kinds of elements out of Si, Fe, Cu, Mg, Zn, Cr, Ni, Gd, Sm, Dy, Ni, Mn, Y, V, Ti with Al by anode oxidation method to develop colors. Namely, the base plate consisting of the aluminium disc 1 forming the alumina layer 2 on its surface in order to reduce the reflectance <=20% or preferably <=10% at 700- 900nm oscillation wavelength of a laser diode to be used for the optical head and 632.8nm He-Ne laser.

Inventors

• 👤 Norihiro Funakoshi
• 👤 船越　宣博
• 👤 Shuzo Fukunishi
• 👤 福西　修三
• 👤 Mikio Takeshima
• 👤 竹島　幹夫
• 👤 Hironori Yamazaki
• 👤 裕基 山崎
• 👤 Yoshihiro Asano
• 👤 浅野　義曠

Bibliographic Details