| 摘要 |
PURPOSE:To increase light absorption efficiency and an optical change quantity by forming a thin recording film in such a manner that there is a distribution of optical constants in the thickness direction of said film and the optical constant near the surface is larger than the internal optical constant. CONSTITUTION:The thin recording film 2 which has the distribution of the optical constants (complex index of refraction n*=n+ik, n: refractive index, k: attenuation coefft., i: imaginary unit) in the film thickness direction, has the optical constant near the surface larger than the optical constant in the inside and generate an optically detectable change by projection of energy rays is provided on a base material 1. Namely, the refractive index difference between the thin recording film 2 and the base material 1 in contact with both boundary faces thereof or an air protective layer 3 is large and the reflectivity of the boundary face is assured; in addition, the internal absorption of the thin recording film 2 can be decreased and, therefore, the reflected light rays from both faces of the thin recording film 2 can be efficiently interference with each other. A large change in the reflectivity over the entire part is thereby obtd. when the optical constant of the thin recording film 2 changes. |
