LEDs are further challenging incandescents with LED maker Cree’s announcement of a lighting product with a colour rendering index (CRI) of 92, putting it among incandescents for colour quality.
“The LRP-38 generates a CRI of 92 at a colour temperature of 2,700K. The tightly-focused beam delivers a centre beam candlepower of 4,000 with a beam angle of 20 degrees,” said Cree. “This light is designed to replace 50-90W halogen PAR38 bulbs in various applications.”
Input power is 12W – with the firm claiming a total delivered minimum efficacy of 42lm/W.
The lamp is designed to last 50,000h in open track fixtures or 35,000h in recessed down lights.
Applications are expected where good colour reproduction is required, such as supermarket produce displays, department stores and art galleries.
For example, Z-Power LEDs from Seoul Semiconductor were used as spotlights for the exhibits at
Da An Art Gallery in Zhongshan City, China.
One benefit of LEDs is that they do not emit ultraviolet radiation, so do not require the filters used with traditional halogen and fluorescent lamps to protect the pictures.
The installation replaced 50W halogen lamps with 7.2W LED spotlights, which according to Seoul Semiconductor could deliver an 85% power saving.
The Z-Power LED P4 series used in the gallery spotlights has the colouring rending index of 93, indicating a high level of natural expression of light colours, and high efficiency, which is optimal for lighting of museums and galleries.
Da An Art Gallery contains the works of Jun Tien Lee, a famous local calligrapher and sculptor. The gallery is replacing the halogen lamps and fluorescent lamps with LEDs in an eco-initiative.
Another supplier, Lumileds is in production with a Rebel LED guaranteed to deliver at least 100 lm/W.
“Creating
solid-state lighting applications is easier because flux binning and forward voltage binning selections are pre-determined to deliver 100lm/W efficacy,” said Lumileds.
Another interesting development is the improvement in the efficiency and lifetime of organic LEDs (OLEDs).
According to one supplier, OLEDs are approaching levels where that could be practical for lighting.
“The recent advances we have made in efficiency, colour and lifetime of our white phosphorescent OLEDs move us closer to meeting the US Department of Energy’s solid-state lighting targets and the requirements of Energy Star,” said Dr Julie Brown, chief technical officer of US-based Universal Display (UDC).
Its demonstration materials produce from warm to cool white with power efficacies between 54 and 102lm/W – almost identical to conventional LEDs aimed at lighting.
“Depending on the specific designs employed, the colour rendering indices [CRIs] varied from 70 to 88, and lifetimes varied from 4,000 to 17,000hour to 70% of a 1,000cd/m2 initial luminance,” said UDC.
The OLEDs range from approximately 2,700 to 4,000K colour temperature and were developed to meet the requirements of Energy Star, the US government-backed energy-efficiency standard.