From warm to cool white: colour-temperature tunable LEDs

November 20, 2014 // By Julien Happich
At electronica, LED manufacturer Everlight introduced what the company claims to be the world's first colour-temperature tunable LEDs in a simple COB (chip on board) package.

After brightness dimming, tunable colour temperature is a feature that allows end users to tune the warmth of the light they receive. Typically, this feature was implemented through the use of multiple LEDs binned from cool white to warm white, behind a diffuser.

With its CHI3030 27V/29W series, Everlight claims to have a very compact solution, with LEDs packaged behind concentric layers of phosphors offering different colour temperatures of white. Depending on how much of warm white or cool white you choose to light up, you can get a precise colour-temperature mix.

A multichip solution, the CHI3030 is the largest such colour-temperature tunable COB LED, measuring 30x30mm and drawing 29W at 27V. It is available with many different tunable ranges, from 2580 to 5700K for the KH Warm White series, to a tunable range of 4745 to 7050K for the KT Cool-White series, with a typical luminous flux of 2760lm for a 2700K warm white to 2990lm for a 5700K cool white. Smaller series are also available with fewer concentric phosphor rings and operating down to 9W.

According to Christopher Keusch, Director of Lighting Business for EMEA at Everlight, such colour-temperature tunable LEDs will become main stream within the next few years, adding extra tuning flexibility while making it easy for luminaire manufacturers to precisely calibrate their products at a fairly low cost.

Everlight is also keen to play in the increasingly popular filament LED market, where strips of LEDs lined up in series are coated in phosphor, to be implemented into traditional-looking filament light-bulbs. The company was exhibiting several such filament LEDs ready for integration by LED bulb manufacturers.

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