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MidOpt Bi Series Filter Bi940

Uniforce Product

Salient Features

Bi Series Narrow Interference Bandwidth

    • 20-35nm FWHM; Narrow bandwidth
    • High transmission ≥85%
    • Designed for use with laser diodes
    • Ideal wavelength separation when multiple light sources of similar wavelengths are present
    • Reflective, mirror-type surface that helps minimize thermal effects
    • Available in sizes up to 79.5mm sq.


APPLICATIONS: Bi Series are popular for life science and laser analysis applications where only discrete wavelengths need to be passed to maximize system performance.



Bi940 trans graphic



Many commonly used IR LED or laser diode illuminators operate at or very close to 940nm. Bi940 filters feature a much narrower band design vs. BN940, which can be beneficial when used in situations where ambient light conditions might otherwise create poor contrast. These are frequently night vision, security, traffic control, LPR and industrial inspection applications.

NIR image sensors used in conjunction with 940nm illumination are also being used to support iris recognition in biometrics. When used as a secondary scanner (simultaneously with a primary, mobile scanning unit), the invisible 940nm band can similarly help improve finger-vein identification protocols. This technology identifies specific individuals using a distinct blood vessel pattern inside one’s hand. Use of a narrow band Bi940 filter can provide insurance in the event of unanticipated changes in ambient/background light. One application that is under development is to verify users in payment transactions instead of relying on a credit card.

  • Useful Range : 930-952nm
  • FWHM : 32nm
  • Tolerance : +/- 5nm
  • Peak Transmission : >85%
  • Surface Quality : 40/20
  • Compatible LED : 940nm
  • Thickness : 1mm

midopt_stabledge-filter-exMidOpt StablEDGE™ optical filters are specifically designed to be less  susceptible to effects from angular shifting seen when optical filters are placed in front of short focal length (<12 mm) camera lenses.
StablEDGE™ filters take advantage of absorptive filter glass to form the leading
edge of the filter passband.This assures no shifting in this region, even when the
lens FOV exceeds 100°.StablEDGE™ designs are  less angle-of-incidence sensitive, inherently more rugged, and are environmentally stable.



Bi940 Transmission Chart


Learn More About

›  Color Separation for Monochrome Imaging

›  Blocking Unwanted Light in Monochrome Imaging

›  How Bandpass Filters Increase Resolution in Monochrome Imaging

›  Near-IR Imaging in Monochrome Applications

›  Fluorescense Imaging in Monochrome Applications

> Learn More About How to Minimize the Effects of Short Shifting

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