LEDs ♦ news digest
an in-situ metrology system with advanced curvature resolution (AR).
This tool uses three laser spots for the curvature measurements as shown in the figure below, and also provides information on wafer curvature asymmetry along two perpendicular directions as it is typical for a-plane III-N growth.
of LED devices.
The jointly developed manufacturing solution, which leverages a combination of AR coating processing equipment and tuneable, durable, inorganic coating material, enables lumen output increases of up to eight percent. The AR coating manufacturing solution can be seamlessly integrated with established production schemes, allowing the coating of LED components at room temperature and atmospheric pressure.
“Improving light efficiency is a constant goal for LED chip and luminaire manufacturers in order to drive down the total cost of LED lighting. However, extracting further improvements in light output from the LED chip design and epitaxial layer growth process has become increasingly difficult and costly.
As a result, any incremental improvements in light output that can be gained from other areas with minimal cost or disruption to the LED manufacturing flow can have a significant impact on reducing overall system cost,” says Antun Peic, business development manager at EV Group.
The in-situ curvature measurements are demonstrated in the figure by a red line for (spherical) curvature and a blue line for curvature asphericity. During the growth of the tensely strained a-plane GaN buffer layer, the curvature (red) increases, while it decreases after the insertion of LT AlN IL.
Thus, the interlayer reduces the tensile strain as in the case of c-plane GaN growth.
However, after the growth of the interlayers, the asphericity (blue in the figure) increases, which indicates an increase of anisotropic strain. This anisotropy has been proven by subsequent ex-situ X-ray diffraction measurements [2].
[1] M. Wieneke
et.al., abstract book ICMOVPE 2012 [2] M. Wieneke et al., abstract book DGKK 2013
EVG and BMT brighten up LEDs
An anti-reflective materials combined with coating equipment and process create ‘total’ AR coating solution to increase lumen output by up to eight percent
EV Group (EVG) and Brisbane Materials Technology (BMT), have introduced a new anti-reflective (AR) coating solution based on BMT’s XeroCoat materials, which is designed to substantially increase lumen output
“Through our partnership with BMT, we’ve developed a turnkey manufacturing solution that has achieved a significant breakthrough in improving LED light efficiency, which can help accelerate new applications for solid- state lighting such as smart lighting and smart building.”
Under a strategic cooperation agreement, EVG has optimized its precision coating systems for BMT’s unique materials and processes, enabling high-yield fabrication of AR coatings with industry-leading performance and cost.
The technology enables the creation of a nano-porous SiO2 coating from a liquid precursor at room temperature and atmospheric pressure on plastic and glass lenses and luminaires. The SiO2 film, which has undergone rigorous testing, including a 2.5-year accelerated aging test equivalent to more than twenty years of field application, is covalently bonded to the surface to give maximum durability and field reliability.
“Our collaboration with EV Group in the solar market over the past several years has proven the ability of our joint- AR coating solution to provide significant improvements in solar cover glass transmission,” comments BMT founder and CEO Gary Wiseman. “We are very excited to begin providing our patented XeroCoat anti-reflective materials to LED lighting customers. Our unique solution provides a simple and cost-effective way for customers to increase lumen output. Working with our equipment partner, EVG, we provide the equipment, materials, and process as a turnkey solution to our customers.”
March 2014
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