Projection method and system utilizing a variable transmittance color switch
AssigneeFujitsu General Limited
InventorsTakayoshi Taniai, Naoki Ebiko, Atsushi Harayama
Life of this patent
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Abstract
A single polarizer projector with a color switch and a projection method thereof, wherein the mean luminance of the inputted video signal is calculated so that the transmittance of the color switch can be controlled by the mean luminance in such a fashion that the transmittance is set to a maximum (100%) while setting the same to a low level (50%), thereby preventing unnatural blackening of relatively dark image for improving the contrast ratio.
Claims16
A single polarizer projector system, designed for displaying color image on a display panel by switching the color to be displayed by a color switch, comprising:
- an image processing circuit for processing a video signal, input into the system, into an appropriate format suitable for said display panel;
- a mean luminance calculation circuit for converting R, G and B signals, outputted from said image processing circuit, into a luminance (Y) signal from which can be calculated a mean luminance during a 1V period;
- a transmittance setter for setting a transmittance of said color switch according to an output from said mean luminance calculation circuit;
- a color switch drive circuit for driving said color switch according to said output from said transmittance setter;
- and
- a panel drive circuit for sending the inputted video signal to said display panel and a synchronizing trigger signal to said color switch drive circuit.
A method of displaying an image using a projection display system, comprising the steps of:
- inputting a video signal into said projection display system;
- projecting a multi-spectrum beam of light onto a color switch;
- selectively allowing a limited-spectrum of light derived from said multi-spectrum beam of light to pass through said color switch and project onto a reflective display panel;
- synchronizing control of said reflective display panel with said color switch so that an image displayed by said reflective display panel corresponds to said limited-spectrum of light passed through said color switch;
- calculating a mean luminance of said video signal based on R, G and B components of said video signal;
- and
- selectively adjusting a transmittance of said color switch based on said calculated mean luminance of said video signal input into said projection display system.
Dependencies are inferred from the claim text.