| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical element which can be manufactured more simply and at a lower cost than a conventional low pass filter and has high optical performance and further which can effectively converge light to an effective area of a solid imaging element like a conventional microlens array does and to provide an imaging optical system having the optical element. SOLUTION: The optical element is disposed in front of the solid imaging element and is made of a translucent substrate. A plurality of first refraction surfaces divided by a first level difference so as to have predetermined constitution are provided on one surface of the substrate. When▵1 denotes size of the first level difference,λdenotes a wavelength of incident light and (n) denotes a refractive index of the substrate, formula (1): (n-1)▵1=λ/2 is satisfied. Further in a relation to the solid imaging element, the optical element is disposed at a position where Nyquist frequency components of light which is made incident onto the optical element and then onto the solid imaging element are cut. COPYRIGHT: (C)2009,JPO&INPIT
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