NIL impact on LED industry - Medium term

From micro- to nano- sized surface pattering

This is the second in a series of articles offering an overview of the impact NIL has on the LED industry. Here we look at advancements in the mid-term that will further enhance Obducat’s marketshare…

Technical advancements are moving towards imprinting with smaller dimensioned surface patterns which, for some LED products, will increase light emission and energy efficiency. On a more general level it will enable bringing production costs down. Currently the standard in the LED industry is based on using micro sized patterns.

Re-shaping to maximize technology’s potential

Micro sized patterns, seen up close, appear as a surface pattern, covering the sapphire substrate with pyramid structures. When a thin layer of gallium nitride is applied, this coating enables the light to bounce off the pyramid surface patterning and emit light. The shaping of these pyramids dictates the level of reflecting power and light emission covering the substrate surface. Surface area size = light reflection capacity. By evolving the patterning shapes to increase surface size, more surface light excitation occurs.  

Introducing nano-patterns

Building upon this light refraction technology, with cost down motivation in mind, LED leaders are interested in moving away from micro surfacing to nano surfacing. Nano-surfacing increases light emission for some LED products but the main interest is based on pulling production costs down. By modulating the pattern surface triangles into softer, rounder half spheres shapes, light reflection is increased. With nano-surfacing, two modifications are occurring which increase light strength: the shapes that make up the surface patterning are morphing as well as their actual size, with the height’s reduction.

3 key benefits from nano-patterns

This is cost effective in a number of ways. Firstly, the move from micro sized patterns to nano sized patterns means, for certain LED products, increased efficiency through more powerful light emission, up to 10%. With the lowered surface height and a less jagged, angular landscape, more surface area is created and with it, increased reflected lighting capacity.   

Another advantage is that a more effective reflection surface also increases heat dissipation efficiency due to more light being reflected upwards instead of bouncing between surface planes in the LED endlessly. Surfaces which do not bounce light upward reflect light back and forth between themselves, essentially holding the light captive and resulting in the build up of heat. This excess heat then needs to be subdued and re-directed outwards with heat management technology- all costs which increase production expenses in LED manufacturing.  

Obducat's Advantage

Yet another benefit with the move to nano sized patterns is via more efficient production costs. Pattern surfaces that are less deep enables the reduction of the amount of consumable materials used in the NIL step as well as reduced processing time on down stream production steps.

CEO of Obducat, Patrik Lundström adds, “The currently used lithography method cannot create the smaller nano sized patterns due to resolution limitations. There is a general view in the LED industry that NIL seems to be the most suitable method for production of nano sized patterns.”