Projector
There are various types of projector, the most commonly known are the slide projector or the over head projector which is used to project an image or information from a positive slide onto a screen or light reflective surface. There is the film projector that projects images onto a screen that simulates motion. And now we have the LCD (liquid crystal display) projector that projects digital images onto a screen.
A projector, whether film, slide or digital works in the same way, in the sense that they project light through a filter through a lens onto a screen or light reflective surface.
The most popular projector today is the LCD projector, used with a computer or computerised device such a DVD player, digital camera or video player, it is used for presentations by sales people, lecturers by concert organisers to project events onto large screens and by home cinema enthusiasts.
LCD projectors use mirrors to split the light that it receives from the input device into three colours particles, red, green and blue. The particles are turned into pixels, the pixels pass through a prism to reconstitute an image which then passes through a lens to be projected onto a screen.
LCD projectors are sub-divided into several models dependent on resolution and ANSI lumens (picture brightness). There are three progressive scan resolutions in popular use, they are; 854x480, 1024x576 and 1280x720. They are sometimes referred to as 480p, 576p and 720p. In the UK we use PAL as opposed to America that uses NTSC, this is the TV and video signals that are transmitted. PAL has 576 vertical lines and NTSC has 480. In the UK a projector with a resolution of 576p will display exactly what it is receiving without any scaling. Scaling is if you have a projector with a higher resolution then the projector has to redistribute the 576 lines over 720 lines, this is a process called scaling and invariably you will lose sharpness and the picture will be softer.
If you are going to be using the projector to view HDTV or Blu ray then the signal being transmitted is either 720p or for true HD 1080p therefore you are going to need a projector with a resolution to match.
Brightness on the other hand will depend on the lighting conditions the projector is going to be used under. As regards lumens a projector with less than 2000 lumens is not worth considering and 3000 to 4500 lumens would be preferable.
