Band-pass filter glass
Band-pass Filter Glass, band-pass filter for short, is a kind of glass allowing the transmission of light within a narrow bandwidth range, with an obvious cut-off effect to short wave and long wave, as shown in the figure. Its spectral characteristic is illustrated by the maximum transmittance (TM) and the wavelength at the peak (λM), front-cut-off wavelength and behind-cut-off wavelength, and half-peak width. Half-peak width is the difference (λ2-λ1) nm between λ1 and λ2 that are corresponding to the half values of TM of the band-pass filter glass. The front-cut-off or behind-cut-off wavelength is the wavelength corresponding to the transmittance of zero on either side of the peak. But there are some types whose transmittance on the back side of the peak can not approach to zero. So they are determined by the transmittance of a certain wavelength. Band-pass filter glass is named DTB in this catalogue, and the wavelength corresponding to TM is used as its serial number.
Band-pass Filter Glass characteristics
NO. Type Maximum Transmissivity (TM/λMnm) Front Cut-off (T/λnm) Behind cut-off (T/λnm) Half-peak Width (λ2-λ1)(nm) Thickness (mm) 1 DBT400 ≥45/400±2 0/320±5 0/525±5 ≤90 2 2 DBT435 ≥48/435±2 0/340±5 ≤2.0/540±5 ≤100 4 3 DBT470 ≥40/470±2 0/340±5 0/600±5 ≤115 4 4 DBT500 ≥48/500±2 0/380±5 0/630±5 ≤100 4 5 DBT530 ≥48/530±2 0/420±5 0/670±5 ≤95 2 6 DBT545 ≥48/545±2 0/400±5 0/720±5 ≤100 4 7 DBT560 ≥40/560±2 0/435±5 0/725±5 ≤104 4 8 DBT600 ≥36/600±2 0/470±5 ≤1.0/800±5 ≤95 4 9 DBT660 ≥44/660±2 0/500±5 ≤2.0/800±5 ≤115 4 10 DBT700 ≥28/700±2 ≤0.5/570±5 ≤2.0/820±5 ≤95 4 11 DBT720 ≥50/720±2 0/500±5 ≤9.0/900±5 ≤140 4 12 DBT740 ≥25/740±2 0/650±5 ≤4.0/900±5 ≤85 4