Absorptive ND filters are one of simple light attenuators to be used to control the amount of light, They possess level spectral transmittance characteristics in the visible region and attenuate light by absorption with minimal reflection. they do not affect the colors of the light Since the filters have low dependency on wavelengths and optically neutral. Absorptive ND filters are useful in light control applications for measuring instruments and exposure control in imaging.
Item
Specifications
Material
Color glass from schott or equivalent
Dimension X×Y(φ)
1×1mm~25.4×25.4mm；φ3~φ25.4mm
Dimension tolerance
±0.05mm
Parallelism
＜10 seconds
Clear Aperture
85%
Surface Quality
MIL40-20
Flatness(per 10mm)
λ/8@632.8nm
Optical density tolerance
Typical ±5%
Coating
Specified by customer