Red & Yellow

Red and yellow filters are long-pass filters that pass light at wavelengths longer than their characteristic cut-on wavelength–typically the wavelength at which the transmission is 50% of the maximum. These filters use absorptive glasses, that are robust, cost-effective and insensitive to angle of incidence. In machine vision, one of their typical applications, they are used in front of a lens on a monochrome CCD or CMOS camera to improve image contrast. The appropriate type of filter has to be selected with respect to the color of the object and the type and/or color of the illumination. These filters are available unmounted or in mounts with all common thread sizes.

Technical Specifications 1)
Filter Type	021 light yellow	022 med. yellow	023 dark yellow	040 yellow - orange	041 red-orange	090 light red	091 red	092 dark red
Cut-on wavelength	460 nm	490 nm	530 nm	550 nm	565 nm	600 nm	625 nm	695 nm
Cut-on wavelength tolerance	± 10 nm	± 10 nm	± 10 nm	± 10 nm	± 10 nm	± 10 nm	± 10 nm	± 10 nm
Surface	5/2 x 0.16 2)	5/2 x 0.16 2)	5/2 x 0.16 2)	5/2 x 0.16 2)	5/2 x 0.16 2)	5/2 x 0.16 2)	5/2 x 0.16 2)	5/2 x 0.16 2)
Wavefront distortion 3)	1 λ	1 λ	1 λ	1 λ	1 λ	1 λ	1 λ	1 λ
Parallelism	1 arc minute	1 arc minute	1 arc minute	1 arc minute	1 arc minute	1 arc minute	1 arc minute	1 arc minute
Diameter tolerance	+ 0 - 0.3 mm	+ 0 - 0.3 mm	+ 0 - 0.3 mm	+ 0 - 0.3 mm	+ 0 - 0.3 mm	+ 0 - 0.3 mm	+ 0 - 0.3 mm	+ 0 - 0.3 mm
Thickness	2.0 ± 0.2 mm	2.0 ± 0.2 mm	2.0 ± 0.2 mm	2.0 ± 0.2 mm	2.0 ± 0.2 mm	2.0 ± 0.2 mm	2.0 ± 0.2 mm	2.0 ± 0.2 mm
1) Specifications for unmounted and uncoated versions 2) Surface specification according to ISO 10110, quality usually similar to MIL 80-50 scratch-dig or better 3) Per 30 mm at 633 nm