Safety of laser pico projectors
Pico projectors are small video projectors, often battery powered. The light source can use light-emitting diodes (LED) or laser diodes. The remainder of this discussion will be about laser pico projectors.
The MicroVision ShowWX+ laser pico projector is about the size of an iPhone
The laser light emitted from a pico projector is very different than light from a laser pointer. It is much more divergent, since the goal is to display a relatively large image -- not a dot.
Regulatory implications
Any laws and regulations that apply to “lasers” should be careful to define how the term applies to high-divergence laser sources such as pico projectors. For example, a law trying to control laser pointer and handheld laser misuse should exclude laser-based pico projectors. Some sample wording is discussed on the page If you are writing a laser law.
Safety implications
Responsible manufacturers take the safety of laser pico projectors seriously. The unit pictured above is Class 2. This is the same as laser pointers below 5 mW (the U.S. legal limit for selling a laser as a pointer).
Class 2 lasers are considered safe due to a person’s natural aversion to blink, move or look away from a bright light. The laser will not cause harm in the time it takes to avoid the beam. However, intentional staring can be unsafe, so use by minors should be monitored -- just as with laser pointers.
More information is available in papers by Dr. Edward Buckley of the University of Cambridge (PDF downloads):
Eye-safety analysis of current laser-based LCOS projection systems
Eye-safety analysis of current laser-based scanned-beam projection systems
Additional resources
Wikipedia page on pico projectors
Pico projector review website