Are RGB laser projectors safe?

Every day more movie theaters are opting for laser-based projection. However, questions arise about the security of these systems. Marcos Fernández, director of Christie for Spain and Portugal, defends in this Tribune that the light generated by a laser projector does not entail a greater risk than the beam produced by lamp-based equipment.

The mere mention of lasers evokes in us images typical of science fiction, of high-powered weapons capable of eliminating entire planets. However, in its most recent configurations, lasers are used in devices that, rather than embodying those destructive forces imagined by popular culture, do so in low-power versions commonly used in technologies such as DVD players, medical devices or presentation pointers. What's more, when used in an RGB laser light (LIP) projector, the light generated is no more dangerous than the light produced by equivalent lamp-based projectors.

When can laser beams be dangerous?

Certain types of lasers, such as those in LIP-type projectors, generate narrow, very intense beams of collimated light. That pure beam of laser light can be harmful to people if it is pointed directly at the eyes or sometimes the skin. However, despite those potential risks, the IEC, an international organization that sets laser standards, recently changed the classification of LIP projectors from laser standard to lamp standard. Despite this, in the United States the use of lasers continues to be the responsibility of the FDA (Food and Drug Administration), which currently requires a special variance or permit each time an LIP-type projector is used.

How to make laser safe

In 2014, Christie became the first manufacturer to obtain a variance from the FDA enabling it to legally sell and install LIP projectors by meeting a full set of safety regulations. Christie achieved that distinction by incorporating several safety measures into its 3-Primary (3P) and 6-Primary (6P) laser projection systems.

Optical path

The pure laser light generated by Christie laser projectors passes through a series of optical elements that evenly distribute the energy over a wide area. When the laser light enters the projection head, it is no longer collimated light, so it no longer emits the dangerous energy levels typical of laser beam light.

Fiber interlock loop

Other protective measures include a patented fiber locking loop, which renders laser light production useless when the access panel is opened, protecting the user from accidental exposure. The projection head also sends a signal over the fiber link to the light source. Failure to receive this signal will indicate the existence of a problem, so the lasers will not turn on.

Security built into the design

In an LIP type projector the most likely occasion of exposure to pure laser light would occur during repair or maintenance. To prevent this, the laser projector has been designed so that the light in all service areas is maintained at safe levels.

There is also a beam stop mechanism, a physical racket that blocks and prevents activation of the laser light sources when the projector is undergoing maintenance or repair. But also, if something interferes with the light beam on the projection head, the system will automatically turn off.

The goal of these safety aspects is to minimize the risk of exposure in cases of unsafe practices or operation of LIP type projectors. As with all high-brightness projection systems, standard safety measures must be observed at all times.

Final thoughts

The same factor that makes laser beams potentially dangerous (the intense concentration of light energy) is also what enables them to generate levels of brightness never seen before.
Although laser sources individually present safety risks when misused, when used in an LIP-type projector with safety features such as those deployed in Christie RGB laser projection systems, the risks associated with pure laser light are drastically reduced.