| 摘要 |
An optical reproduction method is provided that is able to increase recording capacity of an optical recording medium by combining the techniques of light wavelength reduction, signal level multiplication, and recording layer multiplication in an optical recording medium. In the optical reproduction method for reproducing signals based on light reflected from plural pits in the optical recording medium with plural recording layers, a pit depth H, a wavelength lambda of the incident light, and a refractive index n of the substrate of the optical recording medium satisfy: lambda/6n<=H<lambda/4n. The region including the pits is divided into cells each having the same area, and multi-level reproduction signals are generated in response to pit occupation of the cells. Spherical aberration W<SUB>40 </SUB>in light condensed onto the optical recording medium satisfies W<SUB>40</SUB><=0.07 lambdarms.
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