Thanks to a new gallium-nitride-on-silicon (GaN-on-Si) process, Toshiba is able to produce its LETERAS white LEDs using 200-mm silicon wafers. This avoids the typical costly sapphire substrates in relatively small 100- or 150-mm wafer sizes.
Improved luminous efficacy of the second-generation TL1F2 white LEDs is due to optimized packaging (6450 package) and increased optical output power of the GaN-on-Si LED chips. The TL1F2s maintains a full correlated colour temperature (CCT) range from 2700 to 6500 K, with minimum colour rendering index (CRI) values of 80 and 70, respectively. Typical luminous flux of the 1-W LEDs ranges from 104 to 135 lumens, depending on colour temperature and CRI.
Typical driving current (IF) of 350 mA, with a typical forward voltage (VF) of 2.85 V, helps reduce system power consumption. An operating temperature range of -40 to 100°C suits the LEDs for both indoor and outdoor use in applications such as lamps, ceiling lighting, street lights, and floodlights.