The Complete Handbook of Multimedia Projectors

Chapter 1: Understanding Multimedia Projectors

A multimedia projector is a device that takes a digital image or video signal from a source—a computer, streaming device, camera, or media player—and projects that image at large scale onto a wall, screen, or other surface. That simple statement conceals a great deal of engineering and optics. To understand what a projector can do, what it cannot do, and why a particular model will or will not work in your specific venue, you need to understand how it actually works.

Unlike a television, which displays an image on a fixed screen built into the device, a projector separates the display surface from the device itself. This separation creates both freedom and constraints. The freedom is obvious: you can project on any surface large enough, from a screen 8 feet wide to the side of a building. The constraints are less obvious but equally important. Projectors depend on three things: a bright light source, precise optics to focus that light through an image, and a clear path from the projector to the surface with minimal obstructions and ambient light. Understanding these three components—light source, optics, and the operating environment—explains why a projector that performs beautifully in a dark theater fails miserably in a sunlit conference room, and why the cheapest projector at the electronics store may be useless in your actual space.

The Light Source

Every multimedia projector contains a light source. For decades, that light source was a lamp—specifically, an arc lamp similar to