Audience Scanning Lasers

Considered by many to be the “holy grail” of laser effects, audience scanning is where laser light is intentionally projected directly into an audience area, allowing people to interact and actually reach out and touch the light. While this effect is perhaps the most beautiful that can be produced with a laser, it also carries the greatest risk, and requires that the laser operator take certain safety precautions to ensure that the light level does not exceed recognized safety standards. In addition, there are certain regulations surrounding the performance of audience scanning in different geographic territories around the world. Therefore, as an entertainment lighting professional, you must become aware of these regulations in the areas where you perform.

The following diagram provides a great illustration and starting point, to help explain why directly viewing a laser beam can be potentially hazardous.

As the diagram above helps illustrate, the human eye is able to focus laser light much more efficiently than it can other types of light (such as sunlight). Better focusing leads to better concentration of the light. And, just like when holding a magnifying glass to focus a beam of sunlight into a given area, the human eye will focus laser light into a very small spot. At very high levels, the concentrated energy could become hazardous to a person’s eyes.

This is a major reason why there are regulations surrounding the performance of audience scanning, especially in the United States, as well as in some other countries. And, it is also why we at Pangolin strongly urge anyone performing audience scanning, to first understand these laser effects, what makes the effect potentially hazardous, and to learn how to present audience scanning shows safely.

As a world leader in laser show safety, our team here at Pangolin has compiled a wealth of great articles that go on to discuss the various laser safety aspects touched on in this report; including audience scanning safety and the use of lasers in airspace. You can access these articles using the links below:

• Audience Scanning Safety Article – Making laser shows safe and enjoyable, by William R. Benner Jr.
• Laser Safety Thesis A Risk Assessment Methodology for the Use of Lasers in the Entertainment Industry, by John O’Hagan
• Handy Laser Safety Document – A Generic Safety Policy, Risk Assessment, and Contract, by Jeremy Turner

PASS is an advanced laser show safety system, that continually monitors the laser power, scanner signals, and other projector-related parameters. If everything is working safely and correctly, then PASS will never need to interrupt the light output from the projector. However, if there is a minor problem with the show programming such that the beam is traveling too slowly, the beam is scanning an area that is too small, or the beam stops scanning altogether, PASS will momentarily interrupt the light coming from the projector, by manipulating the color and blanking signals.

Once the show resumes safe operation with the laser beam moving sufficiently fast so as to not present a hazard, PASS will allow the light to resume coming out of the projector.

The PASS hardware and software does this in a very intelligent way so as to not destroy the intended visual effect. It is only in the event of a major problem detected within the projector (or within PASS itself) that PASS will take drastic action. PASS aggressively and vigorously protects the audience from system failures.

Patented, award-winning technology that goes beyond scan-fail circuits PASS is significantly more advanced than simple "scan-fail" products. It went through ten years of R&D, and two years of U.S. government scrutiny to determine that it provides true safety. PASS was also reviewed by ILDA judges and received the first place Fenning Award for Technical Achievement. In 2010, PASS was also granted a US Patent.

All of the systems within PASS were designed such that there is redundancy. That is, there are always at least two circuits monitoring any condition (power supply, light output, scanner dynamics, and system logic). For maximum reliability, each of these circuits are implemented in different ways, thus, making it extraordinarily unlikely that they would fail in exactly the same way at exactly the same time. And the output of these circuits are polled, such that all circuits must agree that there is a safe condition, in order for PASS to allow light to emanate from the projector.

Due to its redundant approach, there is no single point of failure that permits hazardous light levels to reach an audience. If any parameter is unsafe, or if a monitoring circuit within PASS fails, it will go into a safe mode where laser light ceases. In fact, PASS will maintain safety even in the face of five simultaneous system failures!

Having undergone intense scrutiny by the laser safety community, and being the safety system within the first projector to receive a CDRH Variance for European-style Audience Scanning, thus allowing Audience Scanning laser shows to be performed in the United States, we believe that PASS is currently the only credible solution to ensure the continued success of the laser entertainment industry.