HP Labs Technical Reports
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Optical Efficiency for Different Liquid Crystal Colour Displays
Keyword(s): optical efficiency; LC displays; phase change; birefringence; polymer dispersed
Abstract: There are at least 6 fundamental types of liquid crystal displays recorded in the scientific literature. Each type exploits a different physical effect to generate a colour image on the display. It is not always obvious how to compare the optical efficiencies of the different types. Even so 'hard numbers' can be found for the transmission and / or reflectance of the displays they often refer to different standards. Some authors use newspaper as a standard for contrast and brightness of the image others use quantities defined by the CIE (Comission Internationale de l'Eclairage) to calculate values for their displays. We define here a 'three-pixel' colour display illuminated by a white light source of 6500K colour temperature and intensity 1 over the display area as our standard and calculate the colour response and contrast for all 6 display types. Viewing angle and aperture ratio are not included in the calculation. This should give us the 'ideal' values for the optical efficiencies.
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