Biomaterial Database

Evaluation of InGaN/GaN light-emitting diodes of circular geometry. 2009

X H Wang, and W Y Fu, and P T Lai, and H W Choi

Semiconductor Display and Lighting Laboratory, Department of Electrical and Electronic Engineering The University of Hong Kong, Pokfulam Road, Hong Kong.

Blue GaN light emitting diodes (LEDs) in the shape of cuboids and circular disks have been fabricated by laser micromachining. The proposed circular geometry serves to enhance overall light extraction on a macro-scale and to improve uniformity of the emission pattern due to the rotational symmetry of the chip. Analysis of the chip shaping effect is carried out by ray-tracing simulations and further supported with mathematical modeling using ideal LED models, and subsequently verified with fabricated devices. In comparison, a 10% improvement in overall emission was observed for circular LEDs over the regular cuboids, consistent with simulations and calculations. The measured emission pattern from the circular LED confirms the axial symmetry of the emission beam.

UI	MeSH Term	Description	Entries
D007204	Indium	A metallic element, atomic number 49, atomic weight 114.818, symbol In. It is named from its blue line in the spectrum.
D008029	Lighting	The illumination of an environment and the arrangement of lights to achieve an effect or optimal visibility. Its application is in domestic or in public settings and in medical and non-medical environments.	Illumination
D008956	Models, Chemical	Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.	Chemical Models,Chemical Model,Model, Chemical
D003198	Computer Simulation	Computer-based representation of physical systems and phenomena such as chemical processes.	Computational Modeling,Computational Modelling,Computer Models,In silico Modeling,In silico Models,In silico Simulation,Models, Computer,Computerized Models,Computer Model,Computer Simulations,Computerized Model,In silico Model,Model, Computer,Model, Computerized,Model, In silico,Modeling, Computational,Modeling, In silico,Modelling, Computational,Simulation, Computer,Simulation, In silico,Simulations, Computer
D004867	Equipment Design	Methods and patterns of fabricating machines and related hardware.	Design, Equipment,Device Design,Medical Device Design,Design, Medical Device,Designs, Medical Device,Device Design, Medical,Device Designs, Medical,Medical Device Designs,Design, Device,Designs, Device,Designs, Equipment,Device Designs,Equipment Designs
D005708	Gallium	A rare, metallic element designated by the symbol, Ga, atomic number 31, and atomic weight 69.72.
D012666	Semiconductors	Materials that have a limited and usually variable electrical conductivity. They are particularly useful for the production of solid-state electronic devices.	Semiconductor
D017076	Computer-Aided Design	The use of computers for designing and/or manufacturing of anything, including drugs, surgical procedures, orthotics, and prosthetics.	CAD-CAM,Computer-Aided Manufacturing,Computer-Assisted Design,Computer-Assisted Manufacturing,Computer Aided Design,Computer Aided Manufacturing,Computer Assisted Design,Computer Assisted Manufacturing,Computer-Aided Designs,Computer-Assisted Designs,Design, Computer-Aided,Design, Computer-Assisted,Designs, Computer-Aided,Designs, Computer-Assisted,Manufacturing, Computer-Aided,Manufacturing, Computer-Assisted
D019544	Equipment Failure Analysis	The evaluation of incidents involving the loss of function of a device. These evaluations are used for a variety of purposes such as to determine the failure rates, the causes of failures, costs of failures, and the reliability and maintainability of devices.	Materials Failure Analysis,Prosthesis Failure Analysis,Analysis, Equipment Failure,Analysis, Materials Failure,Analysis, Prosthesis Failure,Analyses, Equipment Failure,Analyses, Materials Failure,Analyses, Prosthesis Failure,Equipment Failure Analyses,Failure Analyses, Equipment,Failure Analyses, Materials,Failure Analyses, Prosthesis,Failure Analysis, Equipment,Failure Analysis, Materials,Failure Analysis, Prosthesis,Materials Failure Analyses,Prosthesis Failure Analyses