OPTICAL RECORDING MEDIUM AND OPTICAL RECORDING BODY AND METHOD FOR RECORDING AND READING

摘要

PURPOSE:To perform superimposed recording on the same optical scanning track so that the packing density of an optical recording medium can be improved by forming the recording medium of a coating film made principally of plural kinds of coloring matters different in specific light absorptive wavelength. CONSTITUTION:An optical disk and optical recording medium are formed of coating films made principally of plural kinds of coloring matters having light absorptive wavelengths which are different from each other by >=100ns within a range from a visual light band to an infrared ray band. Superimposed recording is performed by irradiating a recording medium 11 (provided with a protective film 13) containing the coloring matters 111 and 112 with laser light beams emitted from plural kinds of, for example, two kinds of semiconductor lasers 151 and 161 from the transparent base plate 12 side of an optical disk 14 thus formed through collimator lenses 152 and 162, a dichroic mirror 17, and a light synthesizing lens 18. Thus packing density of the optical disk 14 can be improved.