According to the National Institute of Standards and Technology NIST report, 18W warm white LEDs and 72W neutral white LEDs can achieve lumen efficiencies of 77.4 lm/W and 89.8 lm/W, respectively.
The University of California, Irvine, Optoelectronics Packaging and Materials Laboratory announced that its warm white and neutral white multi-chip LEDs set a new record for lumen efficiency. Both LEDs use a commercial blue chip. In December 2008, the National Institute of Standards and Technology (NIST) report confirmed the performance of the above two LEDs. All of the above are measured after the LED and the heat sink both reach a thermal equilibrium state of 37 °C.
According to Professor Shi Guojun of the laboratory, the above results are derived from innovations in package design, packaging process, white LED phosphor and packaging process optimization, rather than using any special prototype chip.
18W warm white LED
According to NIST's report, the input power of a warm white LED in a multi-chip package is 18.62 W. When the color rendering index is equal to 91.3 and the color temperature is equal to 3928 K, a luminous flux of 1444 lm, that is, a lumen efficiency of 77.4 lm/W can be produced.
The above is the result of measurement after the LED and the heat sink both reach a thermal equilibrium state of 37 °C. If the LED junction temperature is maintained at 25 ° C according to the general industry standard, the lumen efficiency is expected to be 82 lm / W.
The white light LED uses a blue chip bare chip with an optical power of 260 mW. However, according to a large LED chip manufacturer, the optical output power of the blue chip is up to 571mW. Therefore, if the existing packaging technology and white LED technology are applied to this 571mW blue chip, the lumen efficiency is expected to be 170lm/W.
72W neutral white LED
According to the NIST report, the multi-chip integrated compact white LED produces a luminous flux of 6543 lm with a correlated color temperature of 4455 K at an input power of 72.84 W, with a lumen efficiency of 89.8 lm/W.
The above results were also measured after the LED and the heat sink both reached a thermal equilibrium state of 37 °C. If the LED junction temperature is maintained at 25 ° C according to the general industry standard, the lumen efficiency is expected to be 95 lm / W.
The white light LED uses a blue chip bare chip with an optical power of 260 mW. If the existing packaging technology and white LED technology are applied to the 571mW blue chip, the lumen efficiency is expected to reach 197lm/W.
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