For many professionals in the laser industry, laser safety glasses are a familiar concept. However, for many others, their understanding of these glasses may be limited and they may only use them as required by their company regulations without much knowledge about their functions.
Therefore, this article will explain why it is important to use different colored laser safety glasses depending on the specific occasion.
Laser characteristics
For starters, laser safety glasses are designed to protect against lasers.
As Sun Tzu's Art of War states, “know yourself, know your enemy, a thousand battles, a thousand victories”.
Therefore, it is essential to understand the “enemy” of the laser to understand why laser safety glasses are necessary and how they serve their purpose.
The term “laser” is derived from the light produced by atoms. When electrons in atoms absorb energy, they move from a low-energy state to a high-energy state before returning to their original state. This energy is emitted in the form of photons.
As a result, the emitted photons are coherent, which gives lasers their distinctive monochromaticity, directional properties, and high brightness compared to normal light sources.
In simplest terms, visible light is an electromagnetic wave with a wavelength of approximately 400nm-700nm, according to high school physics.
Electromagnetic waves such as infrared, ultraviolet, microwaves, longwave radio, X-rays, and gamma rays have specific wavelength ranges.
Wavelength and frequency range of seven colors of visible light
Unlike the above-mentioned electromagnetic waves with a specific wavelength range, the laser is an artificial electromagnetic wave generated with a unique wavelength through its own generation principle. This feature is characterized by:
1. Good monochromaticity
In other words, using the same wavelength results in a purer laser color. This can be seen at various laser shows where different types of lasers are used.
2. Good directivity
This means that the laser has a small divergence angle after emission, resulting in a straighter optical path. For example, when measuring the distance between the Earth and the Moon, a laser can be pointed at the lunar laser reflector located hundreds of thousands of kilometers away.
Laser pointing at the moon for range
3. Greater shine
This means that the high concentration of laser energy results in greater brightness compared to ordinary light.
Laser Dangers
The aforementioned characteristics of the laser, also known as “opponent”, make it highly harmful to the human eye.
The aggregative properties of the eye increase its sensitivity to laser light by 100,000 times that of the skin. When laser light enters the eye, it focuses on the retina through the refractive medium, leading to an increase in energy density of more than 10,000 times compared to the energy density in the cornea.
Even low levels of laser energy can cause permanent damage to the cornea or retina. Laser eye injuries can result in a sudden flash, followed by a point of light or shadow of varying colors and sizes, and can cause varying degrees of vision loss, temporary blindness, or photophobia.
It is important to note that not all lasers are visible to the human eye. UV lasers, infrared lasers, 808 semiconductor lasers, erbium lasers, CO 2 lasers and others are all invisible. Ultraviolet light with a wavelength of 100nm-400nm can damage the cornea, while a laser wavelength between 400nm-1400nm can penetrate the lens and damage the retina, causing irreversible eye damage.
Laser wavelengths above 1400 mm are relatively safe. However, in high-power laser environments, such as those found in fiber lasers and CO2 lasers, invisible lasers can still cause serious eye damage if the eyes are unprotected.
Characteristics of laser application scenarios
After understanding the characteristics and dangers of the “opponent” laser, it is essential to be aware of its “attack strategy”. This knowledge will allow us to devise corresponding protection strategies to ensure effective laser protection.
In practical applications, we need to use different lasers to produce wavelengths suitable for various scenarios. Due to the laser's monochromatic properties, most work scenes will only have one or a few specific wavelengths. Therefore, the design and production of protection tools can focus on these specific wavelengths to achieve more effective protection.
Furthermore, the high energy characteristics of the laser, particularly in high power laser applications, make the laser environment more “extreme” than natural light environments. It is similar to a tall building that suddenly rises from the ground without a smooth transition. This extreme environment demands greater protection capabilities from our protection tools.
Laser protective glasses
In summary, when dealing with a relatively simple application environment (with a single, fixed laser wavelength) or extreme scenarios (with high laser intensity), it is crucial to have efficient protection in various application scenarios through a classification refined protective equipment products.
This is where laser safety glasses come in.
The fundamental principle of laser protective glasses is to reflect and absorb artificial lasers that are not found in nature, using different lens coatings and special lens materials. This helps prevent damage to human eyes.
At present, laser protective glasses are mainly classified into absorption type, reflection type and composite laser protective glasses that combine the two.
To meet the protective equipment requirements mentioned above, a diverse product line of laser protective glasses has been developed to achieve “efficient protection in different application scenarios”.
The reason why lenses can display different colors is mainly due to the use of various laser nano-absorbent materials in the lenses. This is done to obtain the most effective protection against a single wavelength laser, which results in the lens displaying different colors.
On the other hand, the different lens colors allow users to easily identify the appropriate usage scenarios for different glasses, thus reducing the need for user trial and error.
Therefore, we can now answer the question posed at the beginning of this article.
The distinct colors of the laser safety glasses represent the ideal application scenarios for each pair of glasses, ensuring safety for all users.
