ULTRA-FINE PATTERN LIGHT EXTRACTION FILMS FOR DIFFUSERLESS LEDPANELS

Optrical has developed a new concept for making more efficient LED light panels at lower cost. The side-lit LED panels use one or two LED strips, a sheet of transparent acrylic (PMMA) that is patterned for the extraction of light (called a lightguide), a reflector and a diffuser. The patterning of the lightguide allows extraction of light from the pool of light within it so that it can be directed to the area being lit.

The patterning of the lightguide, however, is done by methods such as laser machining, mechanical scoring, injection molding or screen printing individually, one at a time. These methods are slow and expensive (expensive machine and tooling, slow operation and high overheads). Optrical has, for the first time, developed a micro-patterned film that can be adhered to an unpatterned transparent material (lightguide) to extract the light coupled of it very efficiently.

Such film, named, light extraction film (LEF) can be produced on reel-to-reel basis at upto 40X higher speeds than the laser machining of light panels. Optrical is currently in the final stage of validating an industrially viable process for reel-to-reel manufacture of LEFs. The LEFs have been shown to reduce total coupling and absorption losses by upto 1/3, thus giving upto 12% more light (or lumens).

The aim of this this project is to develop a radically enhanced LEF that does not require a separate diffuser. We aim to do this by changing both design and materials used within the LEFs at present. This will push the LEF conept to and beyond the current boundaries in design, master tooling and materials.

The LED panel market is set to grow significantly, encouraged by their lower energy usage and therefore to help meet UK's CO2 emmission reduction targets. The current high initial cost of the panels is a hurdle for wider adoption in the UK. The cost of the diffusers in current LED panels is around 25% of the lightguide stack.

The UK manufacturers however, are facing tough price pressure from cheaper chinese imports. The propsed technology has the potential to help UK based (and beyond) manufacturers compete on performance and at the same time be commercially competitive. This project therefore can help create (and save) 8 high technology jobs in UK within 4-years of project completion.