Infrared (IR) cut-off filters are used with color CCD or CMOS imagers to produce
accurate color images. An IR cut-off filter blocks the transmission of the infrared
while passing the visible. This can be done with two optical techniques:
absorption or reflection. Absorptive filters are made with special optical
glass that absorbs near infrared radiation. Reflection type filters are
short-pass interference filters that reflect infrared
light with high efficiency.
We offer two types of absorptive filters:
IRC20 and IRC21 and two types of reflective IR filters: IRC30 and IRC40 which is a new type of reflective filter suitable for
day/night security cameras. It
allows both visible and infrared LED light to pass through. The absorptive
filters are recommended for CCD
imagers while the reflective CMOS imagers. Our standard off-the-shelf
filters are listed blow. If you need a custom filter, please
contact our support.
|Default effective aperture
||Schott D263T or BK7 equivalent for coating filters
Absorptive optical glasses for absorptive filters
||Coating filters: Schott D263T glass: 0.3, 0.5, 0.7 and 1.0mm. Other
thickness available for BK7 glass
Absorptive filters: determined by the absorption requirement
||60/40 scratch/dig. Grade 20/10 or better is
also available on custom basis.
|Spectral transmittance (typical values, not specifications)