This paper discusses the possibilities of the light-emitting diode technology in view of application as an instrument light source, especially for on-line process analyzers and hand-held optical sensors. The results of comparative measurements carried out on the spectral power output of selected NIR LEDs and incandescent lamps are summarized. Some aspects concerning the technical optimization of LED- based instruments are dealt with, and the availability of commercial LED devices with a wavelength range from visible to mid-IR wavelengths, are briefly covered. Finally, some examples of LED-based multiwavelength light source modules developed at VT T Electronics over the past few years are briefly reviewed. These comprise a multiwavelength LED source for pulp and paper applications, a prototype 7- wavelength LED spectrometer for the 3.4 micrometers region, and a second generation 32-wavelength SWNIR spectrometer unit for high performance analyzer applications.
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