What Does the LB Rating Mean on Laser Safety Glasses?

Laser safety glasses are essential and important laser protection equipment for anyone working with lasers in a medical, industrial, or research environment. Understanding the LB rating is one of the key factors when choosing the right safety glasses. But what exactly does the LB value mean? How does it affect laser eye protection? In this article, we will take a deep dive into what LB ratings mean, how they relate to laser wavelength and light density, and why they are critical to ensuring maximum eye safety.

What is an LB rating?

The LB rating stands for Laser Blocking Class. It is a classification system defined by the European standard EN 207 that specifies the level of protection provided by laser safety glasses against various types of laser radiation. The LB value indicates the minimum level of protection provided by the safety glasses at a specific wavelength and power level.

Understanding the format of the LB rating

Take the LB rating of LaserPair laser safety glasses LP-GHP as an example, 315 - 540nm DIRM LB5. Here's what it means:

D, I, R, M – Laser type

315 - 540nm – Wavelength range in nanometers (nm) that the safety glasses protect against

LB6 – Laser blocking rating (the higher the number, the higher the protection level)

Each letter prefix corresponds to the type of laser:

D – Continuous wave laser

I – Pulsed laser

R – Repetitive pulse laser

M – Mode-locked laser

What is the difference between LB value and OD (optical density)?

While OD (optical density) is commonly used in the United States to describe how much laser energy is attenuated, LB values are primarily used in Europe and require physical testing for certification. In general:

LB1 ≈ OD1

LB5 ≈ OD5

However, the key difference is that laser glasses that are certified to EN 207 and have an LB rating must be able to withstand actual laser exposure without damage, not just filter the beam on paper.

Why is the LB rating so important?

Choosing laser safety glasses with the appropriate LB rating ensures:

Prevention of permanent eye damage

Compliance with international safety standards

Applicable to specific laser types and intensities

Failure to use the correct LB rating glasses can result in serious injury, especially when using high-power or invisible laser beams such as infrared.

How to choose the right LB rating glasses?

To choose the right LB rating laser safety glasses, you need to know:

Laser wavelength (nm): Because different laser devices work with different laser wavelengths, you must match the laser wavelength when choosing safety glasses. If you need to protect the wavelength of 635nm, then choose laser safety glasses that can protect against 635nm, such as LP-RHP and LP-RHP-2 laser safety glasses from LaserPair. If you need to protect the wavelength of 808nm, you need to choose laser safety glasses that protect against 808nm, such as LP-ADY laser safety glasses from LaserPair.

Laser Power or Energy Output: If the laser has a higher power or energy output, you will need to select laser safety glasses with a higher LB rating

Beam Type (CW, Pulsed, etc.)

Then, match these parameters with the corresponding LB rating indicated by the manufacturer. To maximize safety, always select certified glasses that meet EN 207 or ANSI Z136.1 standards.

Conclusion

Knowing the LB rating of laser safety glasses is essential for effective laser protection. It not only indicates how much laser radiation the glasses can block, but also ensures that the glasses can physically withstand real-world laser exposure. Whether you are a laser technician, researcher, or medical professional, choosing the right LB rating of laser safety glasses will protect your vision and ensure you meet safety regulations.