| 摘要 |
PURPOSE:To provide the interchangeability of the disk by recording or reproducing necessary information to and from the optical disk memory of a ROM type, DRAW type and rewriting type having <=50% reflectivity by functioning on this memory. CONSTITUTION:An interference film 141 consisting of an electric discharge body and a reflecting film 144 consisting of a metal, etc., are formed on a transparent substrate 130 consisting of glass, plastic, etc., and the reproduced light is made incident from a substrate 130 side. The reflectivity of the disk increases with an increase in the thickness of the reflecting film when the thick ness of the reflecting film 144 is as thin as <=50nm. The reflectivity is nearly constant when the film thickness is >=100nm. The specified value varies with the material of the reflecting film. As a result, the film thickness is decreased down to <=50nm or an Ni-Cr film is used in order to decrease the reflectivity to <=50%. The reflectivity is decreased to <=50%, more preferably about 15 to 30% in order to maintain the interchangeability of the reflectivity. The processing device having the lower interchangeability with the devices and the optical memory system are obtd. in this way. |
