Multimedia Production

MULTIMEDIA PRODUCTION 4(1+3)

Lesson 16: LCD (Liquid Crystal Display) Panel / Projectors)

Working principle

1. To display information, LCD projectors typically send light from a Metal halide lamp through a prism that separates light to three poly silicone panels – one each for the red, green, and blue components of the video signal.
2. LCD projectors contain a separate glass panel for each video signal because it results in better color saturation than using a single panel for all three.
   


3. Metal Halide lamps are used because they output an ideal color temperature and a broad spectrum of color. These lamps also have the ability to produce an extremely large amount of light within a small area
4. Each panel consists of two plates of glass with a layer of liquid crystal between them. As polarized light passes through the panels , When a charge is applied, individual pixels can be opened to allow light to pass or closed to block the light
5. This opening and closing of pixels is what forms the image .The combination of open and closed pixels can produce a wide range of colors and shades in the projected image
   
   
   


6. Here LCD projectors use dichroic mirrors to split the light from the input source into red, green, and blue components. Each then passes through the corresponding panel, where pixels form an image.
7. The three colors are then recombined in a prism before being projected through a lens.
8. The right amount of brightness which is measured in lumens, depends on the lighting conditions the projector will be used under, as well as audience size.
9. A lumen is a unit of standard measurement used to describe how much light is contained in a certain area. It is a part of a photometry group which measure different aspects of light.
10. A darkened home theater requires less brightness than a fully lit conference room.


11. The resolution, or how sharp the image is, of each LCD is determined by the number of cells which are called pixels, with the higher the number of pixels meaning more clarity to the image. Each LCD panel also has the ability to control what color each pixel will be in that particular panel so that when all the light is recombined at the dichroic prism, it will be the right color.
12. Factors in considering LCD projectors are portability, computer connectivity, and input options. LCD projectors with higher resolution weigh more and are therefore less portable.