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High power light emitting diodes (LEDs) continue to increase in output flux with the best III‐nitride based devices today emitting over 150 lm of white, cyan, or green light. The key design features of such products will be covered with special emphasis on power packaging, flip‐chip device design, and phosphor coating technology. The high‐flux performance of these devices is enabling many new applications for LEDs. Two of the most interesting of these applications are LCD display backlighting and vehicle forward lighting. The advantages of LEDs over competing lighting technologies will be covered in detail.

Optical cavity effects have a significant influence on the extraction efficiency of InGaN/GaN quantum-well-heterostructure flip-chip light-emitting diodes (FCLEDs). Light emitted from the quantum well (QW) self-interferes due to reflection from a closely placed reflective metallic mirror. The interference patterns couple into the escape cone for light extraction from the FCLED. This effect causes significant changes in the extraction efficiency as the distance between the QW and the metallic mirror varies. In addition, the radiative lifetime of the QW also changes as a function of the distance between the QW and the mirror surface. Experimental results from packaged FCLEDs, supported by optical modeling, show that a QW placed at an optimum distance from the mirror provides a ∼2.3× increase in total light output as compared to a QW placed at a neighboring position corresponding to a minimum in overall light extraction.

High‐power, large‐area InGaN/GaN quantum‐well heterostructure light‐emitting diodes based on an inverted, or “flip‐chip”, configuration are described. These devices are mounted in specially designed high‐power (≈1–5 W) packages and exhibit high extraction efficiency and low operating voltage. In the blue wavelength regime, output powers greater than 250 mW (1 × 1 mm2 device) and 1 W (2 × 2 mm2 device) are delivered at standard operating current densities (≈50 A/cm2), corresponding to “wall‐plug” efficiencies of 22%–23%. Employing phosphors for the generation of white light, these same devices achieve luminous efficiencies greater than 30 lm/W.

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