With the rapid development and wide application of laser technology, various laser products can be seen everywhere in our life and working environment.
Although some laser products can be used safely, improper use of others can cause serious injury to eyes and skin and even cause fire, electric shock, burns, and other serious hazards.
So how can we know if a laser product is safe or not?
Laser Safety Levels Overview
To allow users to easily identify the danger level of laser products, we classify them according to their harmful mechanisms to human tissues and the degree of injury caused.
The wavelength and power of a laser product determine its impact on different human tissues. The wavelength determines the absorption characteristics of different human tissues for the laser and the mechanism of injury. Power and energy determine the degree of laser damage.
According to the International Electrotechnical Commission standard, laser products are classified into various safety levels based on wavelength, maximum output power or energy.
These levels are like business cards for laser products, representing the degree of damage they can cause and the precautions users need to take.
Therefore, whether you are an ordinary consumer or a professional operator, it is important to understand the level of a laser product and the degree of damage it poses, as well as the precautions that must be taken in order to avoid many laser incidents. wound.
Classification of laser safety levels
According to the International Electrotechnical Commission standard (IEC 60625-1), laser products are classified into seven levels – 1, 1M, 2, 2M, 3R, 3B and 4 – based on wavelength and maximum power. about to leave.
Levels 1M and 2M represent the same level of safety as levels 1 and 2, respectively, but when optical instruments such as telescopes are used, the degree of damage may be amplified beyond levels 1 and 2. Level 3 is divided into two. sublevels, 3R and 3B.
The specific classification and degree of damage represented by each category can be understood through Figure 1 and Table 1.
Table 1: Detailed description of hazards posed by laser level classification
| Laser Levels | Description of laser hazards | Examples |
| Class 1 | Based on current medical knowledge, it is considered safe. Under no circumstances will the eyes be exposed to harmful optical radiation. Or although the product contains harmful lasers, they are placed in corresponding sealed products and no harmful radiation can escape from the casing. | Laser ophthalmic keratometer, DVD player |
| Class IM | Large diameter or high divergence beams. There is no harm under normal use, but when optical devices such as telescopes are used, there may be hazards that exceed Class 1 limits. | Low Power Fiber Optic Communication Lasers |
| Class 2 | Low-power visible lasers (400-700nm) belong to low-risk lasers. The human eye's natural aversion response generally protects the eye, and eye damage can only occur if someone continues to look at it intentionally. | Laser scanners, laser pointers |
| Class 2M | Low power visible lasers (400-700 nm), large diameter or high divergence beams. It falls into Class 2 during normal use, but when optical devices such as telescopes are used, the hazards can exceed Class 2. | laser level instruments |
| Class 3R | There is no damage under normal use, but looking directly into the beam is dangerous. | Laser rangefinders |
| Class 3B | Direct exposure or viewing of secondary beams can cause damage, while stray beams are not dangerous. | Demo lasers |
| Class4 | Direct, reflected or scattered beams can cause damage to eyes or skin. | Laser welding, laser marking machines |
Now that we understand the importance of laser hazard levels, let's take a look at how we can determine the safety level of a laser product.
In fact, all laser products that have undergone rigorous testing and certification have a clearly visible laser safety level mark in a location easily visible to users, as shown in Table 2 below:
Table 2. Laser Safety Level Labels and Warnings
| laser level | Laser Warning Label | Warning text | Personal protective equipment |
| Class I | Class 1 Laser Product | Not required | |
| Class 1M | Laser Radiation Do not view the beam with optical instruments Class 1M Laser Product |
Not required | |
| Class 1C | Laser Radiation See user instructions Class 1C Laser Product |
See user instructions | |
| Class 2 | Laser Radiation Don't look at the beam Class 2 Laser Product |
Not required | |
| Class 2M | Laser Radiation Do not stare into the beam or look with optical instruments Class 2M Laser Product |
Not required | |
| Class 3R | Laser Radiation Avoid exposing your eyes to the direct beam Class 3R Laser Product |
Not required | |
| Class 3B | Warning – Laser Radiation Avoid exposure to the beam Class 3B Laser Product |
Protective glasses, protective gloves, protective clothing, etc. | |
| Class 4 | Danger – Laser Radiation Avoid exposing eyes or skin to direct or scattered radiation Class 4 Laser Product |
Protective glasses, protective gloves, protective clothing, etc. |
Analysis of Common Problems in Laser Levels
According to the classification criteria of laser safety levels, different levels represent different degrees of damage and usage restrictions. Therefore, not all products can be sold on the market with any laser level.
Next, we will discuss some issues related to laser levels to draw attention to them:
1. Should laser products for children's toys meet the Class 1 requirement?
When laser technology is used in toys, whether visible or invisible, special attention must be paid to the fact that children may continue to look at the laser surface in a very dangerous way, out of curiosity and without understanding the meaning of the warning signs. warning, thereby causing serious eye damage.
At present, especially in China, many children can easily obtain laser pens or toy laser projectors, some of which have laser power that far exceeds the Class 1 limit, posing great safety risks.
Therefore, all countries require laser products for children's toys to meet the Class 1 level.
2. Is a Class 1 laser absolutely safe?
Some Class 1 lasers have an inherently very low emission power and therefore do not pose a risk to humans.
However, not all lasers are like this. Many lasers classified as Class 1 can internally use Class 3B or 4 lasers. If we use them inappropriately, such as opening the laser's protective casing or intentionally changing the optical path, it may result in leakage of the higher level laser beam, causing personal injury.
3. Why should indication lasers be classified as Class 2 or lower?
Laser pointers, laser measuring devices and tool equipment with laser indicators that ordinary consumers can access or use generally should not have a level higher than Class 3R.
In some markets, such as Europe and Australia, indication lasers, such as laser pointers, must meet Class 2 or lower requirements to be sold.
4. What should we do if we cannot determine the level of a laser?
During the research and development or debugging process, we may sometimes be unable to determine the laser level of a specific part within a product. In this case, we should not simply assume that its level is the same as that of the laser source or a very low level just because it is problematic.
Instead, we should assume that its level is at least Class 3B or even Class 4 and take sufficient safety measures, such as wearing laser protective glasses and gloves, to avoid accidents.
