GaN-on-Si LEDs catching up with incumbents
Fabricated on 200mm silicon wafers, “luminous efficacy of the TL1F2 white LEDs has been improved compared with the TL1F1 series by optimising the package and increasing the optical output power of the GaN-on-Si LED chips”, said the firm. “The TL1F2 series offers a colour temperature range from 2,700 to 6500K, with minimum colour rendering index [CRI] values of 80 and 70 respectively. Typical luminous flux of the 1W LEDs ranges from 104 to 135 lm depending on colour temperature and CRI.”
These GaN-on-Si lm/W figures are now similar to those from LEDs made with more traditional methods, providing they have been measured ‘hot’ – at say 85C.
Despite its complex epitaxy, which has taken so long to develop, GaN-on-Si is expected to result in cheaper LEDs compared with those made on sapphire and SiC because the substrate is cheaper and can be larger.
The Toshiba devices are supplied in a standard 6450 package measuring 6.4×5.0×1.35mm.
Typical driving current is 350mA, with a typical forward voltage of 2.85V – lower than most ’1W’ LEDs.
Operating range is -40 to 100°C, and applications are expected indoors in lamps and ceilings, and outside in street lamps and floodlights, said Toshiba.
Mass production of the TL1F2 series is scheduled for November 2013.