摘要 |
The invention relates to optical media of ROM, WORM, or RW type that combine the ability to write and read data from one layer using fluorescent and reflective methods. Data is recorded as pits of different depth situated either in two alternating spiral tracks or in the same track. Data is read either sequentially, e.g., first by a fluorescent signal, then by a reflective signal, or simultaneously by using two optical heads, one that is fluorescent and the other that is optical
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