PURPOSE: To provide a disk which gives good CN ratio for reproduction and good SN ratio of reproduced signals, has excellent corrosion resistance, and can be used for high density recording by using an aluminum alloy containing a specified amt. of elements as the component of a reflecting film.
CONSTITUTION: A reflecting film 2 comprising an aluminum alloy is formed on a substrate 1, and if necessary, a protective film 3 is provided under the reflecting film. The reflecting film 2 consists of an aluminum alloy containing the following kinds of elements. (a) At least one element selected from hafnium, niobium, tantalum, and zirconium, (b) chromium and at least one kind of element selected from hafnium and titanium, or (c) at least one kind of element selected from hafnium, titanium, and chromium. Thereby, the obtd. disk gives good CN ratio and SN ratio for high-density recording and has improved corrosion resistance and moisture resistance, which prevents decrease in reflectivity even when the disk is used for a long period.
SHINDO KIYOTAKA
MIZUMOTO KUNIHIKO
HASHIMOTO HIDEHIKO
