Abstract: A system for adjusting the color of a light source comprises a first polarizer to polarize the light source, a fixed retarder with its optical axis at a first angle to the polarized light, an electronically variable retarder with its optical axis at a second angle to the polarized light and a second polarizer to polarize the resultant light. This light source may be used where light of adjustable color is needed, for example in a theatrical spotlight or a liquid crystal projection system.

Abstract: A method and projection television system for projecting images having a plurality of color components, includes a device for filtering a first color component signal from a composite signal to provide a filtered first color component signal. A defocusing mechanism defocuses the first color component signal based on the filtered first color component signal. A gain adjustment device adjusts a gain of at least one other of a plurality of color component signals of the composite signal. An amount of defocusing performed by the defocusing mechanism and a gain adjustment by the gain adjustment device are dependent on a content of the composite signal. In another aspect of the invention, a spot wobble scheme may be employed alone in a static defocussing system, without dependence upon the video signal content.

Abstract: A system for adjusting the color of a light source comprises a first polarizer to polarize the light source, a fixed retarder with its optical axis at a first angle to the polarized light, an electronically variable retarder with its optical axis at a second angle to the polarized light and a second polarizer to polarize the resultant light. This light source may be used where light of adjustable color is needed, for example in a theatrical spotlight or a liquid crystal projection system.

Abstract: In a single panel scrolling raster projection system of the type having a single light source, a single light valve panel, a rotatable element having surface segments for separating the white light into color bands, and field-sequential, line-at-a-time addressing means, one or more of the color bands is sized to have a height in the scrolling direction greater than the height of the panel in the scrolling direction, and sizing the remaining bands to have a scrolling height substantially equal to that of the panel. Color correction is achieved by changing the power of the light source to increase or decrease its illumination during the period in which the panel is substantially entirely illuminated by a color band having a scrolling height greater than that of the panel, and/or by adjusting the scrolling heights of the color bands relative to one another.

Abstract: A projection system includes first and second light sources which are disposed at an angle with respect to each other and are activated during respective different phases of an illumination cycle to illuminate a spot on different sides of a segmented rotary filter wheel. The filter wheel is alternately used to transmit light from one of the light sources, and to reflect light from the other light source, to a light valve, the output of which is projected onto a screen. The wheel segments may be alternately clear and mirrored or may alternately transmit and reflect colors to produce color sequential illumination of the light valve. In addition to filter wheels producing sequences of red, blue, green illumination, including the possibility of splitting a color phase into non-adjacent smaller phases to reduce color artifacts, a simple filter wheel which in two rotations produces a sequence of red, blue, green, cyan, magenta, yellow color illumination, resulting in an expanded color gamut, is also disclosed.

Abstract: A method and apparatus for improving the color rendition of a color television receiver includes variable gamma circuits for exponentially correcting the individual color signals. A user control is added to allow user control over the overall gamma of the color television receiver thereby rendering the colors more saturated. With the inclusion of this user gamma control, a separate control for brightness, which affects the overall bias on the CRT, is now obviated.

Abstract: A method and projection television system for projecting images having a plurality of color components, includes a device for filtering a first color component signal from a composite signal to provide a filtered first color component signal. A defocusing mechanism defocuses the first color component signal based on the filtered first color component signal. A gain adjustment device adjusts a gain of at least one other of a plurality of color component signals of the composite signal. An amount of defocusing performed by the defocusing mechanism and a gain adjustment by the gain adjustment device are dependent on a content of the composite signal. In another aspect of the invention, a spot wobble scheme may be employed alone in a static defocussing system, without dependence upon the video signal content.

Abstract: In a three lamp, three light valve projection system, the lamps are energized sequentially in a three phase illumination cycle. The light therefrom is separated by an optical system composed of a three by three array of nine mirrors, all but one of which must be dichroic, to produce red, green, blue color sequential illumination of each light valve. Each light valve, which is controlled by a different control signal derived from an input video signal, is illuminated by a different color sequence such that during each phase of the illumination cycle, each light valve is illuminated by a different color. When the output beams from the light valves are converged over the same area of a screen, the phases of the illumination cycle occur at the field rate of the input video signal, whereas, when the output beams are arranged to produce a tiled image, the phases of the illumination cycle occur at three times the field rate.