Unique control measures Environmental Trees They are used a lot for termination. Check though if laser goes through, trees sway etc. Seasonal, leaf cover, wind affects. If you’re relying on them as a termination point then they need to be thick enough. Water Choppy water will reflect in lots of places. Reflection may be OK […]
Category: Display laser safety officer
Metering beam power
Thor Labs PM-160 Diffusion slotted over the top ensures the beam spreads evenly over entire sensing area. The sensing area is actually smaller than 1cm2, so you need to adjust the reading you want to see accordingly: 9.5mm aperture = 0.70882cm2 So for 1mW MPE you actually read 0.71mW on the meter They have to […]
Laser Types
LASER – Light Amplification Stimulated Emission of Radiation Characteristics of a laser: Ion laser Original types of lasers. Glass tube filled with inert gas. E.g. argon, crypton. Nobel gasses. Better beam quality than modern diode lasers, 2mm wide beam, solid colour. Old timers often lament how much better their colours were. Electrodes placed each side […]
6 – Laser setup & operation
Inside a laser Scan fail card Laser diode blocks Dichroic mirrors are coated with a wavelength specific reflective coating, so other wavelengths will pass through unaffected Scanners US requires a laser to have 30 second delay after power on before emission. The aperture LED flashes during the 30 second time period. Brass and copper are […]
PLASA Safe use of display laser guidance
You can obtain this guidance here: https://www.plasa.org/guidance-for-display-lasers/ A paid from more detail document, part of IEC 60825, can be obtained from the BSI here: https://knowledge.bsigroup.com/products/safety-of-laser-products-guidance-for-laser-displays-and-shows-1 This forms part of legal and best practice compliance. In the UK and Europe this guidance is the only compliance document that is specifically written for the use of display […]
5 – Safety practices
Hierarchy of controls This is typically presented as a triangle of working through risk: Engineering Controls are really relevant when considering laser design and operation Enclosure – stops beam energy escaping in the event something goes wrong inside the unit (thick metal, able to absorb laser energy) Beam stops / attenuators Galvanometer scanners – directs […]
1 – Legal and regulations
Worldwide IEC EN60825 – International standard for the safety of laser products This is used worldwide, it covers all laser uses (not just display lasers). Requirements and guidelines for safe use and manufacture. Defines a framework for accessing potential risk. PLASA Safe use of display laser guidance Forms part of legal and best practice compliance. […]
4 – MPE
Maximum Permissible Exposure MPE is specified for workers (including performers). There is no legal MPE for the audience! However we do use MPE to set a safe limit for audience beam exposure. The point of MPE is to protect the eyes and skin, based on intended and accidental / unintended exposure.It is the amount of […]
3 – Classifications
The energy capable of coming out of the front aperture of the device. Class 4 >500mW Unsafe for eyeUnsafe for skin Class 3B <500mW Unsafe for eyeUnsafe for skin Class 3R <5mW Generally safe for eye and skin under special conditions Class 2M <= 1mW Safe for eye, but unsafe with viewing aidsSafe for skin […]
2 – Laser Hazards
Thermal Hazard Intense heat Longer wavelengths (towards red) make thermal hazard more likely Thermal hazard depends on power and wavelength Water containing tissues are more susceptible biological material to thermal hazard because water turns to steam and that fractures cells. Damage to cells will occur in nS, so very fast indeed (faster than the scanning […]
