Method for identifying double-layer disc and optical disc apparatus

A method for identifying a double-layer disc comprising:

• obtaining a reflectance of each light by irradiating light of different wavelengths under focused state to each layer of a double-layer disc loaded in an optical apparatus, and identifying if the double-layer disc is a recordable double-layer disc, a rewritable double-layer disc or a ROM-type double-layer disc corresponding to the combination of reflectance of each obtained light,
• wherein when the combination of reflectance of each obtained light is 15% or more for both lights, it is identified as a ROM-type double-layer disc, when the reflectance of one light is 15% or more and the reflectance of the other light is 4% or more and less than 15%, it is identified as a recordable double-layer disc, and when the reflectance of both lights is 4% or more and less than 15%, it is identified as a rewritable double-layer disc.