Neutral gray optical glass is an optical material that uniformly reduces light of various wavelengths in the visible spectrum range (usually 400-700nm). Its core characteristic is "neutrality" - that is, it reduces light intensity without changing the color balance and contrast of the light. It is widely used in fields such as photography, videography, laser systems, scientific instruments, and industrial testing.
1、 Basic Principles and Optical Characteristics
Neutral gray optical glass achieves non selective absorption of light energy by doping specific optical absorbing substances (such as nickel, cobalt, iron oxides, etc.) into the glass substrate, ensuring a flat transmission curve throughout the visible light range and avoiding color cast or distortion. This "neutral" characteristic enables it to accurately reproduce the color of the scene in both color and black and white imaging.
The key parameters include:
Average transmittance (T<sub>p</sub>): refers to the arithmetic mean of the transmittance measured every 20nm in the wavelength range of 400-700nm, and is a core indicator for measuring the ability to reduce light.
Maximum allowable deviation (Q): Refers to the maximum absolute difference between the actual transmittance and the average value, reflecting spectral consistency. The Q value of high-quality products is usually controlled within ± 5%.
Thickness influence: The standard test thickness is mostly 2mm, and in practical applications, the dimming effect can be adjusted by adjusting the thickness or using a combination.