POLARIZING FILTER-DEPOLARIZER Russian patent published in 2023 - IPC G02B5/30 

FIELD: photographic optics.

SUBSTANCE: photographic optics and optical observation systems to eliminate hot spots and reduce the brightness range, enhance contrast in the sky. The polarizing filter contains a linear polarizer located along the light rays and a plane-parallel anisotropic layer of thickness d with an optical axis parallel to the layer boundaries and making an angle of 45° with the linear polarizer axis. The thickness d of the anisotropic layer is chosen from the relation: , where l_c is the temporal coherence length of light in vacuum; n_o is the refractive index of the anisotropic layer for an ordinary wave; n_e is the refractive index of the anisotropic layer of the extraordinary wave.

EFFECT: simplification of the design that does not require high precision in the manufacture of an anisotropic substance layer.

1 cl, 1 dwg