| 摘要 |
A method for making a fresnel lens on a substrate by forming a plurality of annular rings. Each ring has a plurality of steps, with each step having an inner wall and an outer wall, and an upper surface. The first step is formed on the substrate, and successive steps are formed at least partially on the upper surface of the previous step such that the outer wall of each successive annular step is offset from the outer wall of the previous annular step in an outward radial direction.
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