| 摘要 |
PURPOSE:To facilitate tracking even in the case of using a recording material which cannot form a pregroup by constituting a light reflective film of two kinds of materials having different reflectivities. CONSTITUTION:An optical recording medium consists of a transparent hard substrate 1, an optical recording film 2 and the light reflective film consisting of two kinds of the materials 3, 4 having different light reflectivies. Either 3 or 4 of two kinds of the materials constitutes an optical guide track. A light beam is irradiated from the substrate 1 side on such recording medium, then the intensity of the reflected light changes when the light beam deviates from the track and therefore the tracking is possible by detecting the change thereof. The tracking is possible according to such constitution as the formation of two kinds of the materials onto a Bi-substd. garnet film to a pattern shape even in the case of using the Bi-substd. garnet film formed on, for example, GdGa garnet as a recording material.
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