| 摘要 |
PROBLEM TO BE SOLVED: To deposit a thin layer harder than prior art and having much less absorbing properties by specifying atomic % of elements Si, O, N and C contained in the layer based on silicon nitride or oxysiliconnitride. SOLUTION: The transparent base material 1 of glass base material type is covered with at least one thin layer 2 based on silicon nitride or silicon oxynitride. The layer 2 contains by atomic per cent 30 to 60% or particularly 40 to 50% of Si, 10 to 56% or particularly 20 to 56% of N, 1 to 40% or particularly 5 to 30% of O, and 1 to 40% or particularly 5 to 30% of C. The layer 2 is not only hard as compared with other known thin layer containing silicon nitride as basic material but also very transparent. Accordingly, its absorption of a wavelength of a visible range is less or zero. High Si and N contents is required, but mainly it is made of silicon nitride. Characteristics of the layer can be finely regulated by altering a ratio of the component of C and O type. |
