Laser Projection Has Arrived

2018-01-01 / Rob Spearman / Laser Projection

Laser-phosphor projection of Himalayas

High quality commercial projectors utilizing laser-phosphor illumination technology are now shipping and provide a number of key advantages over older lamp technology.

Lamp-based projectors rely on high pressure lamps with typical lifetimes of about 2000 hours. The lifetime is reached when the lamp has worn out to the point it is producing only half its original light output. Lamps are expensive over time, usually $400-700 each and there may be more than one per projector. Unfortunately, lamps dim most quickly when they are brand new. If your projection system is underpowered you may be buying lamps a lot more frequently than you want to just to stay bright enough.

Laser-phosphor projector schematic

In laser-phosphor projectors, lamps have been replaced by (usually blue) laser modules which excite phosphor wheels to produce the other required colors (red and green). See the diagram above of a single DLP chip projector. All laser coherence is removed by the time the illumination exits the projector, so there is no laser speckling or eye safety issues to worry about (other than sheer brightness).

Lasers are much more efficient than lamps, run cooler, and last longer. Lasers degrade linearly, so you get more brightness over the illumination life than you would with lamps. A typical laser module lifetime (to half brightness) is about 20,000 hours! We recommend getting a brighter projector than you really need and then setting a lower contstant light output level (supported on some Barco projectors) so that brightness stays constant until this becomes physically impossible. Running at less than 100% power can dramatically increase the lifetime of your laser modules.

Lasers are easier to color match in multi-projector systems, such as our Digitarium Æthos systems. This is because the spectrum is much more controlled than with a lamp. Lasers also do not have the headache of properly disposing of the hazardous mercury in most lamps.

We expect commercial projectors to switch to laser over the next few years due to the overwhelming advantages. This technology is currently available on all Digitarium Æthos systems, and our Digitarium Lambda Fixed models.

About the Author

Rob is President and co-founder of Digitalis. He spends his time between product development and management responsibilties.

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