One of the fastest-growing segments of the semiconductor
industry is concerned with a new generation of graphic displays for
communications and high-definition television sets. For phosphors that might be
used as the active medium in such displays, the critical characteristics are the
lifetimes and wavelengths of their emissions.
Experiment and Results
To further complicate matters, the lifetime of the phosphor
had to be obtained in a short period (three to five minutes) because of the
rapidly changing character of the material. In addition, the phosphor and matrix
were highly scattering, so stray-light rejection was crucial.
Figure 1 shows the emission spectrum of the final phosphor,
confirming a useful visible emission dominated by the 550-nm peak.
Fluorescence emission spectrum of the phosphor complex, showing luminescence in
the visible range.
In Figure 2 the results of the quick lifetime study (eight
frequencies scanned in five minutes) indicate a three-component system,
dominated by a very fast (10–9 s) decay. This fast emission assures
that the phosphor will produce a high quantum yield within a timeframe
compatible with refreshing the CRT’s screen.
Phase-shift (+) and modulation ratio frequency response (×) of phosphor
This particular investigation of phosphor emission
characteristics was made possible by the excellent stray-light reflection,
sensitivity, and wide lifetime range of the FLUOROLOG-τ®
producing rapid and accurate characterization of the phosphor.
Source: Horiba Scientific
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