A digital projector is an electro-optical machine which converts image data from a computer or video source to a bright image which is then imaged on a distant wall or screen using a lens system. A typical resolution for a portable projector will be the SVGA standard (800?600 pixels), with more expensive devices supporting XGA (1024?768 pixels). The cost of a device is not only determined by its resolution, but also by its brightness. For use in large conference rooms the brightness should be between 1,000 and 4,000 ANSI lumens.

There are 4 competing digital projection technologies: high intensity CRT, LCD projectors using LCD light gates, Texas Instruments' DLP technology and LCOS or liquid crystal on silicon. In 2004 and 2005, LCD front projection has been enjoying a come-back because of the addition of the dynamic iris which has improved contrast up to the levels of DLP.

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