ABSTRACT
This chapter describes the characterization of both GaAs and GaAlAs infrared light-emitting diodes (IRLED) in various size chips and in different packages. It discusses the emission of the photons from the packaged IRLED and presents the advantages and disadvantages of plastic versus metal cans, energy output versus current, and energy output changes brought about by changes in temperature. The lens on the metal package is usually made from a hard glass whose thermal coefficient matches that of the nickel—iron alloy package material. The energy an IRLED emits is in the form of photons, and the photon’s energy is inversely proportional to its wavelength. Infrared-emitting diode power measurement depends on a number of variables that must be precisely defined for design engineers to utilize manufacturers’ data sheet information. IRLED chip centering is much more a function of manufacturing processing than package variation, because the tapered cup is usually identical in both the plastic and metal package.
