| 摘要 |
PROBLEM TO BE SOLVED: To achieve reading with a short-wavelength laser beam when coloring is made and at the same time use an ultraviolet curing resin as a lamination adhesive. SOLUTION: At least a reading side disk substrate 1 is colored by a dye. In this case, light transmissivity at a wavelength region of 630-800 nm is set to 80% or higher, while that at a wavelength region of 600 nm or less is set to 30% or less, thus fully reading an information signal even in the case of reproduction with a short-wavelength laser beam as a high-density disk. Also, in the case of an optical disk where a plurality of disk substrates are laminated, light transmissivity at a wavelength region of 340-400 nm of a disk substrate at a reading side or a side opposite to it is set to 4% or higher. |
