Light-Emitting Diode Module with Adjustable Correlated Colour Temperature

One of the important advantages of light emitting diodes (LED) is the possibility to mount on their basis light sources (LS) with changeable radiation spectrum [1, 2]. White LEDs of RPC TEE OPTEL OPEN COMPANY production based on import blue crystals with the InGaN/AlGaN/GaN heterostructure covered with yellow-green phosphor, have light efficiency up to 42 lm/W at 350 mA current and a rather high correlated color temperature (T(cc)): from 7000 to 5000 K [3]. Yellow LEDs based on crystals with the AlInGaP heterostructure, have luminous efficiency in accordance with [4] up to 35 lm/W at 350 mA current, and their T(cc) = 1450 K. In this paper a light-emitting diode module (LEDM) containing five white LEDs and one yellow LED is described. White LEDs are made based on the InGaN/AIGaN/GaN p-n heterostructures of blue radiation covered with yellow-green phosphor, and yellow LEDs are based on the AlInGaP heterostructures on a silicon substrate. Change of LEDs currents over a wide range allows changing relation of white and yellow LEDs radiation fluxes and accordingly T(y) of the LEDM from 3340 to 9920 K, as well as changing radiation chromaticity (x, y) in the (0.29; 0.27) - (0.39; 0.33) interval. In this case the LEDM general index of colour rendition varies in the interval of 75-82. The LEDM light flux can reach 225 lm at the luminous efficiency of 31 lm/W. The LEDM has solid of lint, distribution being uniform enough by chromatic characteristics.