At last, the author obtained the equation of ray trace in the GRIN ball lens with the index profile which is quadratic and drew some important conclusions.

研究了二次抛物线型的GRIN球透镜的光线轨迹方程序；得出其轨迹为椭圆曲线及一些重要结论。

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GRIN ball lens is a spherical optical element with refractive index is symmetric around a spherical point and varies in spherical radius direction.

梯度折射率球透镜是一种折射率以球心为对称中心，并沿球半径方向分布的球型光学元件。

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In Chapter 2, the refractive index distribution and ray trajectory of GRIN ball lens are studied in theory.

第二章主要从理论方面研究梯度折射率球透镜的折射率和光线轨迹。

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