1 Projection and imaging systems
1.4 Light sources for projectors

There are three types of light sources currently used in projectors - a conventional lam (tube), LED sources and lasers.

In the case of a classical lamp, it is a system, where an electric arc burns between two electrodes and this arc is the source of light.

Long-time proven technology and high intensity output are the advantages.

One disadvantage is a limited lifetime (2000 to 8000 hours), slow start (about 1 minute to full output light intensity).

In projectors that use LEDs as light sources, three LEDs are present for red, green and blue color.

Among advantages are a quick start and long-life operation (20000 hours or more).

The disadvantage is the limitation of the projector's output light intensity to a maximum of 1500 ANSI lm.

Projectors working with laser light incorporate several tens of blue lasers that light up on a rotating disc with a luminophore that emits white light. It is further processed as ordinary light from a lamp. Therefore, conventional light, not a laser beam, comes out of the projector’s lens.

Among advantages, there is a quick start and long-life operation (20000 hours or more). There is no performance limitation of the light output as it is in the case of LEDs.