Lumileds lime green LED for colour-tune lighting

Lumileds has announced a lime green LED, revealing that it a key component in the ‘Hue’ range of colour tuneable LED replacement light bulbs from Philips (which owns Lumileds.

Efficacy is the highest yet from Lumileds – over 200 lm/W at the top end of the highest bin – attributed by the company to lime being close to 555nm, the wavelength that human eye cones are most sensitive to. The data sheet specifies Lime as 567.5nm dominant wavelength (566-569nm). Lumileds green is 530nm (520-540nm).

There is a lot more information in this Lumileds Lime story on Electronics Weekly’s main site.

What is puzzling me is, what is the technology inside this LED.

Greens are notoriously inefficient, and Lumileds is happy to make light direct fron an LED die, or through phophor conversion – It actually makes amber LEDs using both direct and converted die.

Mining the data sheet is tricky because Lumileds specifies some die at 350mA, some at 700mA, some at 25°C, and some at 85°C.

From the curves, is shares characteristics with both direct and converted die, and the forward drop is lower than both blue and gree, while you would expect it to be between them if they are all GaN.

Lumileds lime green LED for colour-tune lighting

I have emailed Lumileds, and await a response.

Expect this blog to get longer as the data sheet reveals its secrets.

Is this a blue die with a phosphor, or a direct-emitting die? – deer stalker on.

Sometime later, having trawled the graphs on the data sheet, I think the following is true:
The whole table is repeated below with the LED part numbers
*All die 1mm2 except ES and Lime which are 2mm2
** calculated from 2.72V at 350mA 85°C, and -2 to -4mV/K. All from data sheet
pc = phosphor converted – pc amber is a GaInN die with a phosphor
– interestingly, there is no trace of a blue bump in the spectrum above.
AlInGaP is used for the first four, and GaInN for the rest – probably .

About The Author

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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