| CPC G02B 5/206 (2013.01) [G02B 5/0242 (2013.01); G02B 5/208 (2013.01)] | 17 Claims |

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1. An optical filter, comprising:
a matrix and fine particles dispersed in the matrix,
wherein the fine particles have a parameter Ds that is not smaller than 8.0 and not larger than 30, the parameter Ds being given by Ds=λ/(B·cos θ·Ra) found from a USAXS pattern, where λ is the wavelength of a X-ray, θ is half of the scattering angle 2θ (rad) giving the peak of the scattering intensity, B is the half width of the peak (FWHM, rad), and Ra is the average particle diameter of the fine particles,
wherein the fine particles form at least a colloidal amorphous array so as not to cause Bragg reflection, and
wherein the optical filter exhibits a white color.
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