Questions and Answers about Laser Safety
Laser safety glasses are high value optical products. They need cleaning and care.
Lease follow these directions carefully
- Goggles, windows, filters and glasses with a damaged or scratched ocular or with filters that have undergone a colour change should not be used anymore.
Contact your dealer for checking or replace them with a new pair.
- When frames are equipped with a metal reinforcement on the inside, the reinforcement is a relevant part of the protection. When the reinforcement is damaged the protection may be impaired.
When Used daily:
- Do not expose the eyewear permanently to daylight or UV-lamps
- Please protect the glasses from scratches and mechanical stress
- Avoid contact with chemicals, acids,alkali and toxic (i.e. reactive) fumes
- Never put down the glasses with filters facing down
- Do not put the glasses on heaters or equipment that may heat up
- Please store the glasses in dry and robust boxes; the original storage box is ideal
- Avoid storage in high humidity; if that is not possible ensure good ventilation.
- You can clean your glasses with clear water and neutral cleaning agents (e.g. a mild, household glass cleaner) and dry them gently with a soft cloth.
Goggles that show any damage whatsoever (e.g. a damaged or scratched filter, colour changes in the filter, damaged metal enforcement of the frames) should not be used. If you are in doubt, please contact our technical support for a safety inspection of your glasses.
Of course we can repair our own frames and replace damaged filters. Please contact Laser 2000 Benelux and one of our customer by phone or mail for details.
The difference is in the resistance time of the filter against a direct laser hit in relation to the specified protection level and the energy or power density of the laser. The European legislation (EN 207) requires that a filter must withstand a direct hit from the laser for which it was designed for under defined conditions for 10 seconds (continuous wave mode) or 100 pulses (pulsed mode). If there is no filter available that fulfils these requirements, we quote (based on the EN 60825) a filter that comes as close as possible to these requirements. This means that the Optical Density (OD) is always correct, but the resistance time of 10 seconds/100 pulses cannot be guaranteed.
This has to do with the resistance time the filter will withstand a direct hit. It is necessary to calculate the damage threshold – which is the highest value that the material can withstand. The unit is power or energy density, i.e. the power or energy per square metre. For this calculation the pulse energy or average power of the laser and the beam area is needed. Without the diameter it is neither possible to calculate the beam area nor the energy or power density. Therefore it is impossible to know what the filter has to withstand in case of a direct laser hit.
The laser beam itself cannot be seen; what might be seen by visible laser wavelength is mostly the spot where the laser beam hits an object or some scattered light from dust in the air. Laser safety eyewear is usually designed as full protection eyewear (EN 207). Such filters protect against laser radiation of the specified wavelength or wavelengths ranges and absorb or reflect the beam completely. So the beam spot even of visible laser radiation is not visible anymore. If it is still visible, this would mean that the protection level of the glasses is not high enough, or that secondary radiation (at a different wavelength) is generated. Please check carefully whether the marking of the laser safety eyewear matches the requirements of the laser.
The protection of carefully selected eyewear will remain stable when hit by the laser throughout a minimum period of 10 seconds and 100 pulses under standardised conditions. Nevertheless, it is under no circumstances advisable to look into the beam directly.
Laser safety goggles are designed to protect your eyes against an accidental direct hit of the laser beam. They are not designed for long-term or intra beam laser viewing conditions.
A properly selected pair of glasses will protect you under standardised conditions against a direct look into the laser, but only for minimum 10 seconds/100 pulses.
The color of absorption filters cannot be chosen at random, but depends on the wavelength the filters protect against. To protect against wavelengths in the UV-region or the lower visible (blue radiation), a yellow or orange filter is usually offered. A red filter is usually used to protect against wavelengths in the green region. Please take into consideration that you may not select glasses by the color. Always make sure that the quoted or available pair of glasses matches the requirements of your laser.
Pure coated filters (interference structure on clear substrates), do not affect the color recognition and possess a high daylight transmission additionally.
Before this question can be answered you must determine the specific requirements of your new laser (wavelength, operational parameters, viewing conditions, etc) and calculate the protection level according to the EN 207/208 standard. When these parameters are known, verify that the marking on your existing pair of Goggles matches these requirements. If you are not sure, please call us. We will carry out the calculation and check for you.
Please note: The thoughtless use of a pair of laser safety Goggles for a different application (different wavelength or different power/energy than calculated before) may cause the loss of your eyesight.
The radiation that is visible to humans lies between 380–780 nm (the exact limits are different in each person). In order to cover all lasers you would need a material that does not transmit any radiation for visible radiation, which means it is completely black. When you block all visible radiation, the only wavelengths left are invisible to the human eye. If you have several lasers in this area, then it is necessary to use several pairs of glasses.
But even if you do not want to completely block all wavelengths or have ’just a few wavelengths‘ to cover, the glasses may be too dark. Usually the protection within a material slowly increases spectrally until it reaches the required protection level at a given wavelength. This means that it not only covers the required wavelength but also areas below and above it (with lower Optical Density). Therefore, if you want to cover several wavelengths in the visible spectrum the Optical Density curves will overlap resulting in dark filters or glasses.
The term ’class 4’ is the laser classification according to EN 60825-1 and ANSI Z136.1. Class 4 designation means that this is a dangerous laser and emitted radiation is an eye, skin and fire hazard. When you work with this laser, laser protective eyewear is mandatory. This classification, however, does not include any information regarding the wavelengths or the required protection levels that the glasses must protect against.