Welding lens work by filtering out harmful radiation emitted during welding. When you weld, the welding arc produces a bright light that can damage your eyes if you’re not wearing proper eye protection. Welding lens are designed to block out the UV and IR radiation while still allowing visible light to pass through. The welding lenses are made of a special material that filters out specific wavelengths of light, providing different levels of protection.

Passive lenses work by using a fixed shade level to filter out the light. The higher the shade level, the darker the lens will be. Auto-darkening lenses work by using sensors to detect the bright light from the welding arc. When the sensors detect the light, they send a signal to the LCD display, which darkens the lens within milliseconds. Once the arc is extinguished, the lens returns to its normal, clear state.