InGaN light-emitting diode stripes with reduced luminous exitance

– WS Cheung, YF Cheung, HT Chen, RSY Hui, E Waffenschmidt, and HW Choi

Microphotographs of the (a) cubic, (b) stripe and (c) ∠-stripe LEDs, driven at 20 mA. Ray-trace diagrams for the respective LEDs are shown in (d), (e) and (f) respectively.

Optics Express, vol. 23, 11, pp. 15021-15028 (2015)

InGaN light-emitting diodes of stripe geometries have been demonstrated. The elongated geometry facilitates light spreading in the longitudinal direction. The chips are further shaped by laser-micromachining to have partially-inclined sidewalls. The light extraction efficiencies of such 3D chip geometries are enhanced by ~12% (~8% according to ray-trace simulations), leading to a reduction of junction temperatures. The effective emission area is also increased four times compared to a cubic chip. The stripe LEDs are thus more efficient emitters with reduced luminous exitance, making them more suitable for a wide range of lighting applications.

DOI: 10.1364/OE.23.015021