| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the color drifts at the time of coloring and color fading and during long-term use and to obtain excellent transparency at the time of color fading by dispersing specific photochromic particles into a plastic base material. SOLUTION: The photochromic particles consisting of the fine crystals of a silver halide having particle sizes made uniform within a range of 50 to 300Åin an average particle size, inorg. oxide layers 2 covering these fine crystals and org. matter layers 3 covering these inorg. oxide layers 2 are synthesized in reversed micelle water micro-droplets consisting of an org. solvent, surfactant and water and are dispersed into a spectacle lens base material. In such a case, the silver halide layers on the inner side consist of the silver halide exhibiting photochromism to impart a photochromic characteristic to these particles. The intermediate inorg. oxide layers maintain the particle size of the silver halide particles at a uniform size and impart the repetitive stability of coloring and color fading to the plastic material. The org. material layers on the outer side impart good dispersibility to the plastic material.
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