BPI is often asked about the general performance of lenses in the near IR portion of the spectrum. . BPI® recently developed the BPI IR 1200, a simple

meter that is designed to check the transmittance of lenses at wavelengths of 780nm , 850nm, 940nm, 1070nm and 1200nm in the near infrared (NIR) portion of the spectrum.

Our most aggressive IR tints (BPI IR Blue) only reach a small blockage at 780nm. Some polarized lenses block into the NIR. Mirror coated lenses block about as well in the NIR as they do in the visible. Some glass lenses have NIR blocking performance.

While this meter will show materials that are not blocking well in the NIR, it does not have the dynamic range needed to verify that a material can be used for welding or direct laser viewing.

The BPI® IR 1200 meter uses LED light sources centered at 780nm, 850nm, 940nm, 1070nm and 1200nm to evaluate lens transmission in these regions The transmission percentage at each range is displayed.

The meter also has caution indicating LEDs which indicate if less than 20% of the NIR is blocked at a particular wavelength. CR-39 material has a small absorbtion at 1200nm. Air (no lens) lights all caution LEDs.

Length          Width       Heigth      Weight       Electrical

6.75"             6.75"        5"               8.5lb          110 VAC, 50/60 Hz, 1 A