QB3/GB28 синий стеклянный оптический фильтр

What is Band pass filter?

The band pass filter is a filter that is adjacent to the cut-off band on both sides of the transmission characteristic band of the spectral characteristic curve. The band pass filter is roughly classified into a wide band filter and a narrow band filter according to the spectral characteristics. The two kinds of filters are usually combined, and the band pass filter is prepared by applying the principle of light wave interference. Pass filters are widely used in various fields.
Bandpass filters can be classified into narrow-band filters and wide-band filters according to spectral characteristics, but there is no clear boundary for this division. Generally, filters with a relative half-width of not less than 20% are called broadband filters.