Single point LED lighting array with tuneable colour output

April 16, 2013 // By Graham Prophet
The Tiger Zenigata LED array is presented as the first single point light source to feature ‘tuneable’ colour temperature output, enabling light output colour to be smoothly adjusted to optimise comfort, productivity and well being.

Ismosys, Sharp Microelectronics’ pan-European sales & marketing representative, is sampling the latest addition to the company’s Zenigata family of chip-on-board (COB) LED lighting arrays. The Tiger Zenigata LED module features independently controllable intermeshed ‘stripes’ of yellow (cool) and orange (warm) phosphors (hence the ‘Tiger’ derivation). 168 blue LED chips are coated by strips of different blends of red and green phosphors, which create the warm or cold white light components. A dual-channel LED driver is used to independently adjust the output of each LED ‘stripe’ and so changes the overall colour temperature output of the array.

The colour temperature humans perceive as “comfortable” depends heavily on the time of day and the activity being undertaken: light output quality that can be smoothly adjusted as necessary throughout the day is believed to optimise comfort, productivity and well being in commercial, industrial and domestic applications, the company says.

The circuit for the 2700K ‘stripe’ is made up of 96 chips arranged in eight parallel strips of 12 LEDs. The 5700K ‘stripe’ is created from 72 chips in six parallel strips. Each ‘stripe’ needs a forward voltage of 37V at a maximum power supply of 700 mA. Any colour temperature between 2700K and 5700K can be realised and depending on the colour temperature chosen the luminous flux emitted ranges from 1,900 to 2,200 lm. The Tiger Zenigata achieves a maximum of 92 CRI for cold white and up to 94 CRI for warm white.

With a circular LES of 17 mm in diameter, the Tiger Zenigata delivers the optical characteristics of a single-point light source, simplifying the design of lighting fixtures by eliminating the multiple shadow effect that can be a problem with multi-dot light sources. The 25W device is mechanically and optically compatible with other Mega Zenigata LED arrays (though with four contacts instead of two) making it easy for existing customers to adapt existing luminaire designs to offer colour-tuning capability. Sharp