What laser safety glasses should I wear for Class 4 lasers?

May 16, 2025

For Class 4 lasers, the following key factors need to be considered when choosing laser safety glasses:

1. Optical Density (OD)

High optical density requirements

Class 4 lasers have very high power, and their protective glasses must have a high optical density. Generally speaking, for Class 4 lasers, the optical density usually needs to reach 5-7 or even higher. For example, in some high-power industrial laser cutting scenarios, the laser energy density is extremely high, and only protective glasses with a high enough optical density can effectively attenuate the laser intensity and avoid eye damage.

Optical density is an indicator of the ability of protective equipment to attenuate laser beams. It is calculated as OD = log₁₀(I₀/I), where I₀ is the incident laser intensity and I is the laser intensity after passing through the protective glasses.

2. Wavelength adaptation

Specific wavelength protection

Class 4 lasers cover a variety of wavelengths, including visible light wavelengths (such as 632.8nm for some red lasers) and infrared wavelengths (such as 1064nm). Lasers of different wavelengths require different protection mechanisms, so laser protective glasses must be designed for the specific wavelength of the Class 4 lasers used.

For example, for infrared Class 4 lasers, protective glasses need to be able to effectively absorb or reflect laser energy in the infrared band. This is because although infrared lasers are invisible, they can cause severe thermal damage to the retina and cornea of the eye.

3. Frame design

Wraparound design

Since Class 4 lasers may produce large-angle divergent beams or scattered light, protective glasses are best designed with a wraparound design. This design prevents the laser from entering the eye from the side, top, or bottom.

In a laboratory environment, when performing operations such as laser optical path debugging, there may be scattered light even if the laser is not directly aimed at the eye. Protective glasses with a fully wrapped design can minimize the threat of this scattered light to the eye.

In short, when choosing protective glasses for Class 4 lasers, factors such as optical density, wavelength adaptation, and frame design should be considered comprehensively, and it should be ensured that they are used under the guidance of professionals and strictly abide by laser operation safety specifications.

Our Hot Selling Products are all eye protection measures for Class 4 lasers. For example, for Class 4 lasers of 632.8nm and 635nm red lasers, we have red laser safety glasses, such as LP-RHP and LP-RHP-2. For Class 4 lasers of 1064nm infrared lasers, such as LP-YHP-2 and LP-RTD-5 etc.

① LP-RHP Laser Safety Glasses

Optical Density: 620 - 700nm OD4+

LB-Rating: 620 - 700nm DIR LB4

Transmittance: 50%

Available for: 632.8nm,635nm, 650nm, 694nm, etc.

What laser safety glasses should I wear for Class 4 lasers?