| 摘要 |
A thin-type spherical lens, fabricated according to the result of the virtual procedures of removing the portion of each of a plurality of lens bodies with different radii of curvature of light-exiting faces, which corresponds to a spherical surface with the optical axis of the thin-type spherical lens as its central axis, and assembling the preserved portions thereof to form a plurality of grooves as the light-exiting faces, which are equivalent to the grooves of the conventional Fresnel lens, wherein the depths or the widths of the plurality of grooves are different, and the curvature radii of the plurality of light-exiting faces are also designed to be different so that the lights emerging from the plurality of light-exiting faces are all focused on an identical point. The present invention can, as compare to the conventional approach, reduce the lens thickness when the radius of the apertures on the lens increased.
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