Switchable color filter and field sequential full color display system incorporating same

Claim 2

A switchable color filter which receives light from a light source having light components that can be combined to form white light, wherein the improvement comprises: three color selective linear polarizing filters optically coupled to the light source to define an optical path; a pair of polarization rotating switches positioned so that each one of the pair of switches is disposed between a different pair of adjacent ones of the three color selective linear polarizing filters; and control means in communication with the pair of polarization switches to selectably pass light of one of three colors or white light along the optical path.

Claim 3

The switchable color filter of claim 1 in which each one of the color selective polarizing filters has a polarization axis which passes light of at least one color which is different from the colors passed by the other two of the color selective polarizing filters.

Claim 4

The switchable color filter of claim 1 or 2 in which each one of the color selective polarizing filters has a polarization axis which passes white light.

Claim 5

The switchable color filter of claim 1, 2 or 3 in which each one of the polarization rotating switches comprises a twisted nematic liquid crystal device.

Claim 6

The switchable color filter of claim 1, 2, 3 or 4 in which the light source is a cathode ray tube emitting a black and white light image which includes components of the wavelengths of light transmitted by the color selective linear polarizing filters.

Claim 7

A switchable color filter which receives light from a light source having light components that can be combined to form white light, wherein the improvement comprises: three polarizing means optically coupled to the light source; one of the three polarizing means comprising a color selective polarizing filter having first and second substantially orthogonally aligned polarization states, the first polarization state passing light of at least one color and the second polarization state passing white light, the color selective polarizing filter transmitting light concurrently through the first and second polarization states and being positioned to receive and optically couple to the other two polarizing means the light emitted from the light source; a pair of polarization switching means positioned so that each one of the pair of polarization switching means is disposed between a different pair of the three polarizing means; and control means in communication with the pair of polarization switching means to selectably pass light of one of three colors or white light.

Claim 8

A switchable color filter which receives light from a light source having light components that can be combined to form white light, wherein the improvement comprises: three polarizing means optically coupled to the light source; one of the three polarizing means comprising a color selective polarizing filter having first and second substantially orthogonally aligned polarization states, the first polarization state passing light of at least one color and the second polarization state passing white light, the color selective polarizing filter transmitting light concurrently through the first and second polarization states and being positioned to receive and optically couple to the other two polarizing means the light emitted from the light source; a pair of polarization switching means positioned so that each one of the pair of polarization switching means is disposed between a different pair of the three polarizing means; and control means in communication with the pair of polarization switching means to selectably pass light of one of three colors or white light.

Claim 9

The switchable color filter of claim 6 in which one of the three polarizing means comprises a linear polarizing filter.

Claim 10

The switchable color filter of claim 6 or 7 in which one of the pair of polarization switching means comprises a polarization rotating switch.

Claim 11

The switchable color filter of claim 8 in which the polarization rotating switch comprises a twisted nematic liquid crystal device.