Optical comb filter

An optical comb filter for a color television camera means having a color-separation striped filter and a camera tube for obtaining color television signals, said optical comb filter comprising:

• a plurality of optical comb filter element means respectively comprising flat plates of a transparent anisotropic substance having double refractivity and having optical comb filter characteristics for attenuating and removing respective specific space frequencies which do not have mutual relationships of odd-number multiples, said mutual relationships being determined by said color-separation striped filter and frequencies that are odd-number multiples respectively of said specific space frequencies, light advancing through said optical comb filter means in a divided state as normal and abnormal light and exiting from said optical comb filter means with a separation space therebetween as determined by the filter element means, said filter element means being disposed so that the direction of separation between the normal and abnormal exiting light coincides with the horizontal scanning direction of the electron beam of the camera tube;
• and at least one phase plate means interposed between neighboring optical comb filter element means for converting linearly polarized light exiting from a front one of said neighboring filter element means, with respect to the direction in which light advances through said optical comb filter and causing circularly polarized light to enter as incident light into a rear one of said neighboring filter element means.