Optical information recording medium

Abstract

Abstract PURPOSE:To enable tens of thousand times of recording, erasing and rerecording as desired and to enable long-term preservation of record with the simple construction of a recording film which permits reproducing and erasing by constituting said recording film of an amorphous film contg. a metallic component to form a shape memory alloy when irradiated with a light beam as well as carbon and hydrogen. CONSTITUTION:An Ni-Ti-C film is formed to 500Angstrom thickness by reaction sputtering in gaseous CH4 on an acrylic resin disc base plate having, for example, 300mm. diameter and 1.5t with an alloy of Ni50Ti50 as a target. Such discoid optical information recording medium is rotated 600 times per minute and information is recorded thereon by irradiating a semiconductor laser beam having 50ns pulse width and 3mW power. When the information is reproduced by using the similar laser beam having the decreased power, the S/N obtd. with the reproduced output of the signal is >=40dB. If the laser beam having the power increased to 9mW is irradiated thereto, the recorded information is erased. Information is again recorded thereon when the laser beam of 3mW is thereafter irradiated.

Inventors

• 👤 Noburo Yasuda
• 👤 安田　修朗
• 👤 Norio Ozawa
• 👤 小沢　則雄
• 👤 Akio Hori
• 👤 昭男 堀

Bibliographic Details