Patent ID: 8724221

Claim:
An optical filter, comprising: a substrate; a filter film attached on the substrate having alternating layers of high reflective layers and low reflective layers to form a plurality of Fabry-Perot resonators, wherein a basic optical thickness of the high reflective layers and the low reflective layers is one fourth a central wavelength (λ 0 /4) of incident ray, and where each of the Fabry-Perot resonator high reflective layers has two high reflector layer films and said low reflective layers have a low reflective layer spacer where said low reflective layer spacers are between the high reflector layer films; wherein the low reflective layer spacers in the Fabry-Perot resonator which is most proximal to the substrate, and in the Fabry-Perot resonator which is most distal to the substrate, have an optical thickness respectively in a range between four times the basic optical thickness and fourteen times the basic optical thickness and wherein a sequence of the optical filter is: H(LH)^2 AL (HL)^3; H(LH)^3 4L (HL)^3; H(LH)^4 6L (HL)^4; H(LH)^3 6L (HL)^3; H(LH)^4 6L (HL)^4; H(LH)^3 6L (HL)^3; H(LH)^4 6L (HL)^4; H(LH)^3 4L (HL)^3; H(LH)^3 BL (HL)^2 H; Ns wherein H indicates a high reflective layer with a basic optical thickness (λ 0 /4); L indicates a low reflective layer with a basic optical thickness (λ 0 /4); Ns indicates the substrate; 4≦A≦14, and 4≦B≦14; A indicates times the basic optical thickness of the low reflective layer spacer which is most proximal to the substrate; and B indicates times the basic optical thickness of the low reflective layer spacer which is most distal to the substrate.