Commercial lamp phosphors

The choice of sensor material determines range, sensitivity, and stability. By considering the latter factors, it is found that inorganic insulating compounds, such as most lamp phosphors and many solid state laser materials, are the most suitable materials for thermometric applications. Indeed, these materials are most commonly used in the existing commercial fluorescence thermometer schemes. 

BaMgAlioOn activated by Eu2+ (BAM Eu2+) is used as a commercial blue phosphor in fluorescent lamps or plasma displays. However this material is relatively unstable against thermal... 

Just as in the field of lamp phosphors and (partly) cathode-ray phosphors, CaW04 lost its leading position to rare-earth activated X-ray phosphors (see chapter 8). As a salute to this old champion, but also for your information, we give in Fig. 1.6 the crystal structure of CaW04 which illustrates the build-up of the lattice from Ca ions and luminescent WO4 groups, and in Fig. 1.7. an electron micrograph of a commercial CaW04 powder. 

Figure 7.55 Comparison of commercial fluorescent lamp phosphors, showing clear differences in the chemical composition of the materials. The sample powders required no sample preparation prior to analysis.

Sunlamps A sunlamp is similar to a black lamp, except that a different type of phosphor is used and the lamp envelope transmits UV. Figure 16.5 shows a typical spectral distribution from a commercial sunlamp. The wavelength corresponding to maximum power is shifted to lower wavelengths (— 310 nm), compared to black lamps, and there is significant intensity down to 270 nm. However, the intensity decreases rapidly above 330 nm. The mercury lines can again be seen superimposed on the phosphor fluorescence. 

The emission characteristics of a particular lamp are dependent on tube current, mercury pressure, phosphor composition, phosphor coating procedure, tube composition, and the frequency of the ballast used. Since these lamps are produced for a very competitive commercial market, much of the production information is considered proprietary and not published. Changes can be made, sometimes without the knowledge of customers. 

It should be clear that the 32T8 lamps with rare earth phosphors perform much better than the prior fluorescent lamps used for commercial... 

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