Red-blue-green solid state light sources using a narrow line-width green phosphor

Significance 

One of the key challenges in solid-state lighting is to improve the radiant efficiency of green emitters. Because of the inefficiency of green emitters, the Luminous Efficacy of Radiation (LER) of a high efficiency Red-blue-green mixed white light is considerably lower than blue-bumped phosphor converted white emitters. Meanwhile, there was a well-known trade-off between the efficiency of the source and the color quality of the light it emits, which means sources with high efficiency always emit light with poor color quality. This largely limited the application of high efficiency sources.

In contrast to conventional color LEDs with a spectral width of 30nm, researchers from Rensselaer Polytechnic Institute, Anqing. Liu, Aloha Khanna, Partha Dutta, and Michael Shur took a new approach and developed narrow-line phosphor color LEDs have the spectral width of 7nm. Using a narrow bandwidth green phosphor with the peak wavelength closely aligned with the peak in the human eye sensitivity leads to the improvement in the Light Efficacy of Radiation (LER) of 35 to 50 lm/W compared to the traditional RGB sources.

The color rendition property of light estimated by the Color Rendering Index (CRI) also significantly improves. Combining the narrow band green phosphor with a conventional wide band green phosphor allows for trading off these improvements against the deviation from the Planckian locus.

The light sources with the narrow band green phosphor have considerably better energy efficiency and improved color quality are especially beneficial for a variety of applications such as home, outdoor spaces, industrial ware-houses, public places.

It demonstrated large potential in saving energy, reducing greenhouse gas emissions, and providing light with improved visual comfort.

Red-blue-green solid state light sources using a narrow line-width green phosphor

 

REFERENCE

Liu, A. Khanna, P.S. Dutta, and M. Shur. Red-blue-green solid state light sources using a narrow line-width green phosphor. Optics Express, Vol. 23, Issue 7, pp. A309-A315 (2015).

Go To Optics Express

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