| 摘要 |
PURPOSE:To obtain a practical contrast ratio and a practical responding speed by forming an EC element on the interface between a higher refactive index part as a light wave guide and a lower refractive index part formed at the outside of the higher index part. CONSTITUTION:An EC element 2a, 2b is formed on the interface between a core 1 made of higher refractive index (ncore) material as a light wave guide and a clad 3a, 3b made of lower refractive index (nclad) material. The EC element is composed of a transparent cathode 2b1, a thin film 2b2 forming color by electrolytic reduction, an insulating film 2b3 of a protonic conductor, a thin film 2b4 forming color by electrolytic oxidation and a transparent anode 2b5 arranged in order from the core side. Even if a very thin transparent film exists between the higher and lower refractive index media, total reflection is caused, yet when the Ec element is colored, incident light is absorbed in the element, and the reflectance R to the core is made <1. The ratio between the quantity of light reaching the outside after repeating reflection n-times in the transparent state and that in the colored state is made 1:R<n>. |
