| 摘要 |
PROBLEM TO BE SOLVED: To provide a graded index lens which can efficiently condense light and emit light in nearly parallel beams, and to provide an optical device which can use the light from a light source with high efficiency. SOLUTION: When the graded index lens is constituted in such a manner that the refractive index n (r) decreases proportional to the square of the radius (r) in the radial direction and that the refractive index n (z) in the direction of the optical axis (z) increases in the propagation direction of light from the incident position based on the incident position on the optical axis (z), light can be efficiently condensed and emitted as nearly parallel beams. The graded index lens can be used for a condensing member for various kinds of optical devices. |
