9 March 2015 A novel design and process for improving the efficiency and reliability of an AC direct LED chip
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Abstract
We have developed a low-cost alternating current (AC) direct light-emitting diode (LED) chip in which bridge rectifiers are implemented within a multi-cell array. The chip was designed and fabricated to form a ladder type electrical circuit of integrated multi-cells for direct operation with high voltage AC power source. Through a new isolation process technique, the luminous flux in the multi-chip LEDs increased by 5%, which is ascribed to the increase of active area in the chip. In this paper, we report on the effects of a cell array design on the luminous efficiency, and a new process to improve the device performance. The 2 W device exhibited a typical luminous efficiency of 85 lm/W at a color temperature of 3000 K and color rendering index (CRI) 80. Furthermore, an advanced design to overcome the optical and electrical degradation by the high reverse voltage applied to a bridge rectifier are also discussed.
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Yong-Il Kim, Yong-Il Kim, Chan M. Lim, Chan M. Lim, Wan-Ho Lee, Wan-Ho Lee, Jin-Young Choi, Jin-Young Choi, Seung-Hwan Lee, Seung-Hwan Lee, Gi-Bum Kim, Gi-Bum Kim, Young-Soo Park, Young-Soo Park, } "A novel design and process for improving the efficiency and reliability of an AC direct LED chip", Proc. SPIE 9383, Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XIX, 93830F (9 March 2015); doi: 10.1117/12.2086718; https://doi.org/10.1117/12.2086718
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