being also used as track layers of pre-formatted layers (tracks or pits G11B7/2407)

Full Title

Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation , reproducing using an optical beam at lower power ; Record carriers therefor (G11B11/00, G11B13/00 take precedence) > Record carriers characterised by shape, structure or physical properties, or by the selection of the material (characterised by the arrangement of information on the carrier G11B7/007) > Layers; Shape, structure or physical properties thereof > Substrates > being also used as track layers of pre-formatted layers (tracks or pits G11B7/2407)