| 摘要 |
PURPOSE:To improve diffraction efficiency and to reduce the propagation loss of a light guide which has a higher refractive index than a substrate by forming a light guide layer which has curved grating areas at irregular intervals on the light guide, and forming a clad layer which has a lower refractive index than the light guide layer thereupon. CONSTITUTION:Variation in the refractive index of the substrate by an ion exchange method is utilized to form the light guide layer and diffraction gratings. Namely, irregular interval curved grating areas 30 having the higher refractive index than the substrate are formed at part of the surface of the substrate 30, and then the light guide layer 34 having the higher refractive index than the substrate is formed in the surface area of the substrate. Then, the clad layer 36 having the smaller refractive index than the light guide layer 34 is formed to obtain a light guide lens. Thus, the light guide lens applied with variation in the refractive index of the substrate by the ion exchange method has large variation in refractive index and the transmission loss of the light guide is small. |
