More Efficient and Constant Display Backlighting with Osram-LEDs
2013-7-31                     Source:
Earlier, the Smart Lighting Engineering Research Center of Rensselaer Polytechnic Institute wisdom Lighting Engineering Research Center announced that it has succeeded in integrating the LED and power transistors on the same gallium nitride (GaN) chip. The researchers said that this innovation opens the door to a new generation of LED technology, because it is cheaper to manufacture, more efficient, and the new features and applications are far beyond the lighting category.

Currently, the core of LED lighting system is LED chips making from gallium nitride, but many external components such as inductors, capacitors, silicon interconnects, and wires are to be installed or integrated into the chip. However, the integration of these essential elements into a large-size wafer will increase the complexity of lighting product design once more. In addition, the assembly process of these complexes LED lighting systems is quite slow, not only requires a lot of manual operation, but also the price is expensive.

A study conducted by T. Paul Chow, professor in the Department of Electrical, Computer, and Systems Engineering (ECSE) at Rensselaer, aims to solve these challenges through developing a chip with components all made from GaN. This fully integrated stand-alone chip simplifies the production of LED, also can reduce assembly steps and required automation. What's more, LED devices made with monolithically integrated chips will have fewer parts to malfunction, higher energy efficiency and cost effectiveness, and greater lighting design flexibility.

Chow and the research team directly grew a GaN LED structure on top of a GaN high-electron-mobility transistor (HEMT) structure. They use several kinds of basic techniques to interconnect the two regions, creating what they are calling the first monolithic integration of a HEMT and an LED on the same GaN-based chip. The device, grown on a sapphire substrate, demonstrated light output and light density are comparable to that of standard GaN LED devices. Chow expressed that the study is an important step toward the creation of a new class of optoelectronic device called a light emitting integrated circuit (LEIC).