| 摘要 |
PURPOSE: To obtain a substrate, for an optical recording medium, whose S/N ratio is high and whose dropout is small by forming an address pit which satisfies a specific condition. CONSTITUTION: The wavelength of a beam for recording and reproducing is designated as λ, the refractive index of a light transmitting layer through which the beam for recording and reproducing is transmitted is designated as (n), a track pitch is designated as P, the phase depth of every address pit AP is designated as (d), and the top depth and the bottom depth of the address pit are designated respectively as WT, WB [where W=(WT+WB)/2]. Then, every address pit AP which satisfies λ/8n<=d<λ/4 and P/2<=W<P can be formed. A low-cost one-beam apparatus may be used as a cutting apparatus which forms a groove for every address pit AP, and a low-cost optical recording medium can be obtained. In addition, since data is recorded on the groove, the intensity of an address signal can be increased when the depth of the groove is made deep. |
