摘要 |
PROBLEM TO BE SOLVED: To provide a low-pass filter, controlling optical performance easily and with good accuracy, facilitating manufacture, and manufactured with stable quality inexpensively to be suitable for mass productivity. SOLUTION: This low-pass filter 10 includes a structure 10A in which lens bodies 13 having a convex-shaped in section extended in one direction are arrayed with a substantially uniform pitch P and an intermediate body 15 disposed in a groove 14 in the state of filling in the groove 14 between the lens bodies 13 of the structure 10A, wherein the lens bodies 13 are formed of a first material, the intermediate body 15 is formed of a second material, the depth of the groove 14 is set to d (μm), and when the refractive index of the first material is n1, the refractive index of the second material is n2, and a difference between the refractive index of the first material and the refractive index of the second material isΔn, the value of d*Δn (μm) ranges from 0.028 to 0.366, and the pitch of the lens bodies ranges from 0.5μm to 100μm. COPYRIGHT: (C)2009,JPO&INPIT
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