The next big thing in car headlights is pixel light. It enables the light to be distributed in many different ways. Using a new technical approach with 30,000 pixels, the recently presented Liquid Crystal HD system provides an almost unlimited number.
The majority of cars on our roads only have two or three distribution patterns. All of them need to have high beam and dipped beam. Fog lights are optional but many cars have them in place. In day-to-day traffic, often none of the three light distribution patterns is one hundred percent right. That’s why drivers in Central Europe drive with dipped beam 97 percent of the time, although, without disturbing anyone, many areas could do with getting more than their usual share of light. Obstacles on the road, for example.
Pixel light can change that. A camera continuously analyzes the traffic situation ahead of the car and controls the lighting. All areas that won’t dazzle any human eyes get full light. To achieve this, these headlights use many individual light sources, with each illuminating a very specific area. LEDs are ideal for that. Headlights that are already on the market have between around 20 and 100 LEDs in a matrix arrangement, which is why these systems are also called matrix lights. They allow a great deal of masking and illumination, probably a few dozen to hundreds of light distribution patterns.
Pixel light gets really sharp when there are a lot more individual light surfaces, but smaller. This would allow the system to cast less or no light at all onto a highly reflective traffic sign that would usually disturb the driver.
The idea and pixel light itself are nothing new. As early as the 1990s, developers thought about using the principle of a slide projector for car lighting. But it was only LEDs and digital technology that made pixel light ready for series production. Around two years ago, Osram, Daimler and headlight manufacturer Hella presented the Micro Advanced Frontlighting System (µAFS). It offers as many as around 3000 pixels per headlight which can all be individually controlled, with each pixel corresponding to one LED from Osram.
Hella has now presented a new principle. It’s called Liquid Crystal HD. The name liquid crystal indicates an LCD display which is positioned between the LEDs and the lens of the headlight. Known from other applications, these LCD displays can be pretty much transparent, but, when controlled, can dim individual areas – they’re common in modern TVs and computer screens, for example. In Liquid Crystal HD headlights this “display” dims down the light of individual LEDs. The technology is so precise that it can mask out or allow through any individual light source to form a lot of individual sectors. As few as 25 high-power LEDs in the Hella system will now be turned into around 30,000 pixels.
This not only allows a high number of finely graded light distribution patterns to be produced, but also lets developers dream of additions such as projecting information onto the road. Zebra crossings and cycle paths could be highlighted with light. Pedestrians and cyclists who are badly illuminated or not at all could be seen better, and above all, earlier. Taking the idea even further, sat nav arrows or even information from cell phones such as “xyz is calling” could be projected onto the road.
But here is where the uncertainties start. Authorities responsible for regulations are very cautious about applications like these. After all, this information would be seen by all road users and would potentially confuse them. These additions are still not allowed anywhere.
And before going into series production some problems still need to be solved. The LCD display also swallows light in the non-dimmed areas. But more than anything, the high requirements to withstand heat and cold are a challenge for Merck, the company developing the display. It’ll probably be another two and a half years before Liquid Crystal HD is introduced to the roads. The only thing that is certain is that it’ll be in a Porsche because the sports car manufacturer is Hella’s development partner.
The lighting company is already showing some of the technology’s details in a promotional video.