Color polarizers for polarizing an additive color spectrum along a first axis and it's compliment along a second axis

A color polarizer made by the process comprising the steps of:

• specifying a desired transmission spectrum profile for said color polarizer, said spectrum having an additive primary color along a first polarization axis and the complementary subtractive primary color along a second, orthogonal, axis;
• approximating said profile by a Fourier series;
• apodizing said series;
• using network synthesis to determine a retarder stack which provides the apodized series;
• and
• assembling said color polarizer by combining in series a linear polarizer and said retarder stack.

A method of providing light switchable between three primary colors, comprising the steps of:

• providing a color filter comprising;
• first, second and third linear polarizers positioned in series;
• first and second retarder stacks, each comprising two or more retarders, said first and second retarder stacks positioned between said first and second polarizers and between said second and third polarizers, respectively;
• and
• first and second polarization switches, positioned between said first retarder stack and said second polarizer and between said second retarder stack and said second polarizer, respectively;
• impinging white light on said color filter;
• and
• switching said first and said second polarization switches;
• wherein the number of retarders in said first and second retarder stacks, and the retardances and orientations thereof are such that said color filter switches between three primary colors.

A digital camera comprising:

• a color filter comprising:
• first, second and third linear polarizers positioned in series;
• first and second retarder stacks, each comprising two or more retarders, said first and second retarder stacks positioned between said first and second polarizers and between said second and third polarizers, respectively;
• and
• first and second polarization switches, positioned between said first retarder stack and said second polarizer and between said second retarder stack and said second polarizer, respectively;
• wherein the number of retarders in said first and second retarder stacks, and the retardances and orientations thereof are such that said color filter switches between three primary colors;
• and
• a receiver in series with said color filter.

A field sequential electronic camera comprising:

• an electronic receiver array;
• an optical imaging system that is optically coupled to the electronic receiver array;
• a color filter system that is optically coupled to the electronic receiver array, the color filter system controlling the transmission of a plurality of colors that are received by the electronic receiver array in sequence, and including:
• first and second retarder stacks, each comprising a plurality of retarders, wherein the first retarder stack transmits a first additive primary color along a first polarization axis and transmits a complementary color of the additive primary color along a second polarization axis;
• and
• a polarization switch positioned between the first retarder stack and the second retarder stack, the number of retarders in the first retarder stack, and the retardances and orientations thereof, are such that the color filter switches between a first color and a second color that are recorded by the electronic receiver array in sequence to form a color image.

A method of making a color polarizer, comprising the steps of:

• specifying a desired transmission spectrum profile for said color polarizer, said spectrum having an additive primary color along a first polarization axis and the complementary subtractive primary color along a second, orthogonal, axis;
• approximating said profile by a Fourier series;
• apodizing said series;
• using network synthesis to determine a retarder stack which provides the apodized series;
• and
• assembling said color polarizer by combining in series a linear polarizer and said retarder stack.