| 摘要 |
PURPOSE:To raise the cooling speed for recording and erasing, to reduce thermal shock in multicycle operation and to improve cycle characteristics by incorporating nitrogen into ZnS-SiO2 mixture films provided as protective layers on both sides of a recording thin film. CONSTITUTION:On one side of a transparent substrate 1, there are successively formed a first protective layer 2, recording thin film 3, second protective layer 4, and reflecting layer 5. Information is recorded or erased by irradiation of laser light, etc., to thermally change the optical state of the recording thin film 3. The first and second protective layer 2, 4 are dielectric layers comprising a mixture of ZnS and SiO2 into which nitrogen is incorporated. The dielectric material thus prepared is a mixture material of mixture films of ZnS and SiO2 and nitrides of Zn and Si, which realizes a film having little isolated Zn or Si, namely, a dense film with little defect. The obtd. film has improved mechani cal strength and large effect for repetition of recording and erasing for many times. The protective layer itself has large thermal conductivity. Thereby, the optical disk has excellent recording/erasing characteristics and stable cycle characteristics. |
