The 850nm band-pass filter is used in NIR imaging system to eliminate the influence of surrounding background light, including the visible and NIR. This filter is to increase the signal/noise ratio of the imager. The applications include secure monitoring, visual telephone, visual doorbell, digital telescope and other imaging systems. Band-pass filters are designed to isolate a region of the UV,visible,infrared spectrum. This is accomplished using a complex process of constructive and destructive interference.Band pass filters have bandwidths (measured at half-peak transmittance levels) less than 6% of the center of wavelength value.Our band-pass optical filters and narrow band-pass filters are coating on transparent optical glass or colored optical glass Application: CCTV camera,video doorbell,surveillance camera,digital telescope,IR receiver,telemetry controls,laser rangerfinder,laser speed measurement,biological detection,projector,Fingerprint Identification System,Human Face Identification System, Barcode Scanner Substrate:B270,BK7， Float glass IR sensor IR CCD Camera We focus on designing, developing and manufacturing various applications of Infrared (IR) thin film coatings 650nm 850nm 880nm 940nm 980nm 4260nm T≥85% White=1% Nominal FWHM=10nm Diameter Sizes (mm) 10,12, 15.0, 25.0, 4----60max Thickness (mm) 0.7—8.5 max