摘要 |
An optical filter for screening out infrared and ultraviolet light includes a transparent substrate and a film stack formed on the substrate. The film stack includes a number of high refractive index layers and a number of low refractive index layers alternately stacked one on another. The film stack is represented as follows: (3.5H3.5L)<SUP>7</SUP>(2.5H2.5L)<SUP>7</SUP>(HL)<SUP>6</SUP>(0.76H0.76L)<SUP>6</SUP>, wherein, H represents a high refractive index layer having a base optical thickness equal to one fourth of a reference wavelength associated with the optical filter, L represents a low refractive index layer having a base optical thickness equal to one fourth of a reference wavelength associated with the optical filter, expressions enclosed in each parenthesis represent filter cavities, and superscripts represents the number of repetitions of the expression enclosed in that parenthesis.
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