LED lamps

Typical light output versus current (L—I) and efficiency curves for double heterostmcture TS AlGaAs LEDs lamps are shown in Eigure 8. The ir LED (Eig. 8a) is typically used for wireless communications appHcations. As a result, the light output is measured in radiometric units (mW) and the efficiencies of interest are the external quantum efficiency (rj y. = C y., photons out/electrons in) and power efficiency. As a result of the direct band gap... 

Eig. 8. Light output (—) vs current (L—I) and efficiency curves (-) of double heterostmcture TS AlGaAs LED lamps where the composition of the... 

Scenario 3 This phase would roughly comprise of post-2020 period. In this period, the key event expected to happen would be larger penetration of light emitting diode (LED)-based lamps as their prices would become competitive as compared to present prices of CFL. The prices of CFL as a result are expected to fall further. It is thus desirable to implement the master plan in phases, as when the LED lighting becomes affordable at competitive price, the off take of CFLs/FTLs would slow down and plateau out. As LED lamps do not contain mercury, the elaborate recycling system would not be required for the end-of-life LED lamps. 

It is however, desired to implement the master plan in phases, as when the LED lighting becomes affordable at competitive price, the off take of CFLs/FTLs would slow down and plateau out. As LED lamps do not contain mercury, the elaborate recycling system would not be required for the end-of-life LED lamps. 

Device Cathode-ray tube Plasma display panel Fluorescent lamp Phosphor-converted LED lamp... 

It should also be noted that the effective activation spectrum of photosensitizers is not necessarily exactly the same as their absorption spectrum in solution. The peak wavelengths may be shifted by several nanometers, due to binding of the photosensitizer to biomolecules (e.g. proteins). If a narrow wavelength source (e.g. laser) is used, it is important to match the wavelength to the true in vivo activation peak, so this needs to be determined, typically by studies in animal models. With broad-band sources (LEDs, lamps), this is less critical. 

LED lamp with injection moulded conductor tracks... 

Fig. 14.29 EL spectra of LED lamps based on 380- to 385-nm LED chips. Lamp SI is coated with (Ba, Eu) MgAlioOi7 Mn, lamp S2 with Luo.98V04 2.0%Bi, lamp S3 with (Ba, Eu)MgAlioOi7 Mn and Luo.9gV04 2.0%Bi, and lamp S4 with (Ba, Eu) MgAlioOi7 Mn, Luo,98VO4 2.0%Bi -", Sr4Ali4025 Mn, and Luo,98V04 2.0%Bi -". The image for each lamp is inserted beside the corresponding EL curve. Reproduced from Ref. [36] by permission of John Wiley Sons Ltd.

FIGURE 10 Schematic illustration of a discrete LED lamp. The LED chip is attached to a reflecting cup on an electrical lead. A wire bond connects the LED to a second electrical lead. The chip is then encased in an encapsulant. [From Haitz, R. H., Craford, M. G., and Weissman, R. H. (1995). In Handbook of Optics, 2nd ed., Vol. 1, McGraw-Hill, New York. With permission.]... 

High-brightness LEDs are expected to operate at high optical power densities, with junction temperatures reaching -200° C, a wide range of external temperatures, and humidity levels that could exceed 90% relative humidity (RH). Therefore, it is of critical importance to investigate the operational limits of any LED phosphor and to develop techniques and materials that will improve the phosphor and LED lamp performance under extreme operating conditions. 

Noguchi M. How to Use Visual LED Lamps. Transistor Technology, Supplemental Issue, Hardware Design Series No. 8, CQ Pub, 1999, pp 8-16. 

Light emitting diode (LED) lamps show great promise as a future star of energy-saving lamps for general llghfing. 

Figure 12.27 shows the EL spectra of the LED lamp under pulsed operation. 

Figure 12.29 Variation in pulsed power with drive current for LED lamp for different duty cycles.

The LED lamps (Figure 1.16) emit a relatively narrow spectral output at high intensity (Figure 1.17) so it is essential that the LED lamp matches the UV adhesive... 

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