Samsung’s new LED chip technology, dubbed “PixCell”, is designed to activate the adaptive drive beam and other headlight functions with sophisticated granular control of individual pixels. (Photo credit: Image provided by Samsung.)
Samsung Electronics has announced a new auto-headlight technology called PixCell that can control 100 individual pixels or segments in what appears to be a monolithic LED chip. The design uses barriers developed in the structure between adjacent pixels to eliminate crosstalk and allows the device to deliver a contrast ratio of 300: 1. Meanwhile, the functionality of a PixCell-based projector is captured in software that controls the driver’s electronics, allowing a headlight to provide high beam, low beam, or adaptive high beam (ADB) functionality.
Samsung describes the PixCell LED as “monolithically integrated”. Generally, in the field of electronics, a monolithic device is a device in which several components are developed on a monolithic substrate. For example, advanced digital integrated circuits have millions of transistors integrated on a monolithic substrate with the transistors created during a multi-step process at the wafer level. Likewise, LEDs are grown in reactors in an epitaxial process. But usually the individual LED chips are then isolated and when used in arrays they are combined on another substrate.
We have asked Samsung for details on the use of the term “monolithically integrated” and have not yet received a response. It is certainly possible to cut a PixCell sized monolithic structure in an LED board. But Samsung said the opaque barriers that isolate each pixel or segment are silicon in nature. And while you can grow LEDs on a silicon wafer, the growth layers on top of that substrate should be a compound semiconductor such as gallium nitride (GaN).
Phraseology aside, PixCell’s functionality is quite special. The pixel level control means, only part of the beam can be active at any time. The software can aim the light where it is needed. For example, light can be directed at the radius of a curve that a car is rounding, while light that might distract an oncoming driver is eliminated in real time. We first addressed ADB technology when Audi rolled out Matrix headlights in 2013.
The photo near the PixCell module doesn’t do the tech justice in terms of the device’s scale. This is because the printed circuit board (PCB) looks big and complicated. But the light-emitting area (LES) of the actual LED component is only 15.4×2.7 mm. We assume that Samsung approached the LES as a rectangle even though the photo shows this to be not entirely true. The circuit board includes the complex driver electronics needed to individually control 100 pixels. Samsung has not released the size of the PCB, but said it is reducing the overall size of an individual flagship assembly by 30-50%. A video released by Samsung dramatically shows the downsizing of a set of PixCell-enabled headlights.
“More than just a source of automotive lighting, Samsung’s PixCell LED is based on new lighting technology designed to improve road safety and driving comfort,” said Un Soo Kim, senior vice president of the LED sales team at Samsung Electronics. “Starting with PixCell LED, we will introduce bespoke lighting solutions well suited for future automobiles, including electric and autonomous vehicles.”
Of course, Samsung is far from alone in offering innovative approaches to ADB design. In the fall of 2019, we covered Osram Opto Semiconductors and Nichia’s announcements on enabling technology for ADB implementations. Osram showed a array with 1024 pixels called Evyios which would be delivered on a hybrid device rather than a monolithic one. And the Nichia product relied on dense integration of Infineon transistors into the driver circuit for a 16,000 pixel array.
Returning to Samsung, the company said it has already delivered enough PixCell components to power more than 300.00 EVs with this technology. Samsung has not identified the automaker involved.
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