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.

General Specifications:

Parameter	Value
Default unit	mm
Default effective aperture	90%
Material	Schott D263T or BK7 equivalent for coating filters Absorptive optical glasses for absorptive filters
Dimensional tolerance:	+/-0.1mm typical
Thickness(mm):	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
Surface quality	60/40 scratch/dig.  Grade 20/10 or better is also available on custom basis.
Spectral transmittance (typical values, not specifications)