LED produces warm white light, high efficiency, true colors

Nov. 6, 2009
OSRAM Opto Semiconductors has developed an LED that offers high efficiency, excellent color rendering and a pleasant warm white light. The prototype is the first to offer the three important properties that together are essential for general illumination applications, namely a color temperature of 3000 K, a color rendering index of 82 and an efficiency of 104 lm/W.The pleasant light from this warm white LED is the result of an advanced conversion process. Not only is the quality of light excellent, but the efficiency with which it is produced is also ground-breaking. The combination of these properties is essential for the widespread use of LEDs for general illumination as the warm white light color is targeted specifically at the residential sector. Up to now, efficiencies exceeding 100 lm/W have been achieved only in the cold white spectrum. Dr. Frank Baumann, project manager for the development of warm white LEDs at OSRAM Opto Semiconductors, explains, “The successful combination of high quality of light and excellent energy efficiency will bring the commercial breakthrough for LED technology even closer. Efficient, pleasant light is no longer just a vision.”At 3000 K, the light color of the LED is similar to that of a halogen lamp. Its color location is precisely on the Planckian curve, and the light is exactly white showing no shift to the green spectral region. With an operating current of 350 mA and a chip surface of 1 mm2, the prototype of the new single-chip LED achieves a brightness of 124 lm, which corresponds to an efficiency of 104 lm/W. These record results are based on in-depth OSRAM expertise in providing a new chip architecture in conjunction with improvements in silicon crystal growth technology, improvements in the converter mix, and a high-efficiency package. OSRAM will be gradually integrating the new technologies into production.