AN INTELLIGENT COLOUR TEMPERATURE CONVERSION FUNCTION WITH MULTI-PRIMARY COLOURS FOR INDOOR SOLID-STATE LIGHTING

Abstract

Colour temperature (CT) conversion function is particularly important and requisite for LED lighting comes with multi-primary colour (MPC) LEDs. The colour conversion holding better brightness performance with isotemperature line or the quadrangle of ANSI C78.377 was introduced in this paper. CT conversion with maximal brightness on isotemperature line for MPC lighting can be resolve by the concept that the optimizing point is one of the intersection points determined by the lines of gravity-centre and the isotemperature line. However, the optimal converting point can be determined by the relation between the line of centre of gravity and the quadrangle of ANSI C78.377. From the simulations, the percentage difference between the maximal and the minimal brightness of the colour converting points in the quadrangle of 6500K CT was about 13% of the minimal brightness. Therefore, this paper proposes the intelligent CT conversion functions to hold better brightness performance with multi-primary colour LEDs.