In the field of laser protection, the performance of laser protective glasses is directly related to the safety of the wearer. Understanding the parameter indicators usually engraved on the lenses of laser protective glasses and how to judge the pros and cons of these parameter indicators can better help you choose the glasses that suit you.
1. Parameter indicators usually engraved on the lenses of laser protective glasses
- AB (attenuation factor): indicates the degree of attenuation of laser energy by the lens.
- LB (minimum aperture): used to measure the ability of the lens to block lasers.
- OD (optical density): indicates the attenuation ability of the lens to laser radiation of a specific wavelength.
- IRM (instantaneous response measurement): evaluates the rapid response ability of the lens to laser radiation.
- CE mark: If the lens meets the EU EN207/EN208 standard, the CE mark may be marked.
- Wavelength range: mark the laser wavelength range that the lens can protect, in nanometers.
- Visible light transmittance (VLT): indicates how much visible light the lens can transmit.
- D, R and IR: stand for Density (density or optical density), Reflectance (reflectivity) and Infrared (infrared wavelength range) respectively.
2. Judgment methods of these parameter indicators
- AB (attenuation factor): evaluated by measuring the attenuation of the lens to the laser energy of a specific wavelength. This involves using a laser source to emit a laser beam of a certain power and then measuring the laser power after passing through the lens. According to international or national standards, such as EN207/EN208 or ANSI Z136.1, determine the minimum attenuation factor required for laser protective glasses at different wavelengths.
- LB (minimum aperture): evaluated by measuring the minimum laser beam diameter or area that the lens can block. Tests are performed using laser beams with different diameters, and the maximum laser beam diameter that the lens can completely block is recorded. Also based on international or national standards, determine the minimum aperture value required for different categories of laser protective glasses.
- OD (optical density): calculated by logarithmic function, expressed as OD = log10 (incident light intensity/transmitted light intensity). The laser intensity incident on the lens and the laser intensity after passing through the lens are measured to calculate the optical density value. Determine the minimum optical density value required according to different laser wavelengths and application scenarios.
- IRM (Instantaneous Response Measurement): The lens is illuminated by a rapidly changing laser radiation source and the instantaneous response time of the lens to the laser radiation is measured. Although not all standards require IRM testing, some high-end applications or special occasions may require this parameter.
- CE mark: If the laser protective glasses have passed the relevant EU safety certification, such as EN207/EN208, they will be awarded the CE mark. This means that the product has met the EU safety requirements.
- Wavelength range: The laser wavelength range that it can protect will be directly marked on the lens in nanometers. Users can choose the appropriate wavelength range based on the actual laser equipment used.
- Visible light transmittance (VLT): It is evaluated by measuring the transmittance of the lens to visible light. When choosing laser protective glasses, it is necessary to balance the relationship between visible light transmittance and laser protection effect.
- D, R and IR: These parameters usually need to be considered comprehensively. For example, optical density (D) reflects the attenuation ability of the lens to laser; reflectivity (R) is related to the surface coating of the lens, which helps to improve the reflection ability to laser; infrared wavelength range (IR) indicates the type of infrared laser that the lens can protect.
3. What kind of parameters indicate better product quality
- High optical density (OD) value: The higher the optical density value, the stronger the attenuation effect of the lens on the laser, thus providing better protection. However, too high an optical density value may affect the wearer's visual clarity and comfort. Therefore, it is necessary to balance the protection effect and visual experience when choosing.
- Wide wavelength range coverage: Laser protective glasses should be able to cover a wide range of laser wavelengths to cope with laser radiation of different wavelengths. If the lens can cover a wide range of wavelengths from ultraviolet to far infrared, it can provide more comprehensive protection for the wearer. The wide range of wavelengths also reflects the technical strength and manufacturing level of the product.
- Balance between low visible light transmittance (VLT) and high protection effect: Visible light transmittance (VLT) indicates how much visible light the lens can transmit. A lower VLT value may mean better laser protection, but a too low VLT value may affect the wearer's visual clarity. High-quality laser protective glasses should increase the VLT value as much as possible while maintaining a high protection effect to ensure that the wearer can maintain a good visual experience during wearing.
- Compliance with international or national standards: Laser protective glasses that meet international or national standards usually mean that their quality and performance have been recognized by authoritative organizations. These standards include EU EN207/EN208, US ANSI Z136.1, etc. Choosing laser protective glasses that meet these standards can ensure that the product has reached a high level in terms of protection performance, material safety, and manufacturing process.
- Other auxiliary functions: In addition to basic protection performance, some high-quality laser protective glasses may also have other auxiliary functions, such as anti-fog, anti-scratch, light and comfortable. These functions can further enhance the wearer's experience and safety. However, it should be noted that these auxiliary functions are not the only criteria for measuring product quality. When choosing, you should weigh them according to your actual needs.
Evaluating the quality of laser protective glasses requires considering the comprehensive performance of multiple parameter indicators. High optical density value, wide wavelength range coverage, balance between low visible light transmittance and high protection effect, compliance with international or national standards, and other auxiliary functions are all important factors in judging the quality of products. When choosing, users should make comprehensive considerations based on their actual needs and budget to choose the best quality products for themselves.