Samsung integrates wafer-level microreflectors into multi-pixel LEDs
Another implementation consisted of a single 4.8×19.2mm LED die forming an array of 192 (6×32) individual pixels (sized at 550x690um), each embedded into a silicon recess forming reflector walls. The large LEDs were built on Samsung’s 8″ wafers and the individual pixels were obtained through a cavity-filling phosphor deposition process, eeNews Europe was told at the stand.
Here the reflective silicon walls allow for a higher contrast ratio compared to conventional micro-LED arrays (up to 500:1), with an extremely narrow dark-spacing (only 20um of spacing between two adjacent pixels).
The silicon walls act as micro collimators and remove the need for one of the most sophisticated part in adaptive headlamp design. Collimators are expensive to manufacture and require precision assembly, here the silicon walls control the beam shape at the source.
Depending on customer demand, the aspect ratio of the die could be specified differently for mass production, with integrated drivers if needed. The 4.8×19.2mm die would have a luminous flux of 3800lm at 1.6A, drawing 54W. Samsung hopes to have such pixel lighting modules for the market by 2019 or 2020. The company’s roadmap anticipates that by 2023, it could deliver 20,000 pixels LED chips in 70×280 arrays measuring just 3.1×12.5mm (with an individual pixel size of 45x45um).
Samsung Electronics – www.samsung.com
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