| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a gradient index type optical element which has a large diameter and a free refractive index distribution pattern by concentrically combining a specific number of element transparent bodies which are different in refractive index from one another and made hollow like a cylinder. SOLUTION: Cylindrical element transparent bodies E2 , E3 , E4 , E5 , E6 , E7 , and E8 which have mutually different refractive indexes n2 , n3 , n4 , n5 , n6 , n7 , and n8 and nearly the same internal diameters as other external diameters and an element transparent body E1 which is a column having nearly the same external diameter as the internal diameter of the element transparent body E2 and has a refractive index n1 are prepared. Those are concentrically combined and then heated in this state by a proper heating means for, for example, high-frequency heating, and consequently mutual contact surfaces are molten and stuck to unite the respective element transparent bodies. The cylindrical lens which is thus obtained has a refractive index distribution which is parabolic from the center to the outer periphery and the respective element transparent bodies are made thick to obtain a state which is substantially the same with an ideal parabola. |
