BonaFideReviews posted an article on the topic of digital projectors

A digital projector is an electro-optical machine which converts image data from a computer or video source to an image which is then displayed 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.

Digital Projection in Your Home Theater