Challenges of HD-Pixelated Projection Modules in Headlamps with Increasing Demands on Resolution

The trend in modern car headlights is to bring more and more light onto the road to increase driving safety. However, this will be violated during glare-free scenarios when using pixel modules, with rather large pixels or low resolution. Smaller pixels or higher resolution will not only solve this issue, but also open the door to other applications, such as projected infotainment for road users. Nowadays, highly pixelated headlamp modules, based on DMD or microLED technologies, enable the possibilities for early warnings through symbol projections on the roads, or even individualization through so-called coming home / leaving home animation projections on the walls. Compared to DMD technology, the high-definition headlights having pixelated LED sources, experienced a significant reduction in resolution. Although this is not on the path towards achieving higher resolution systems, but the new technology offers advantages, which are remarkably attractive for HD headlamps. Less module complexity, larger field of view (FoV), and higher luminous intensity on the road can be listed in this regard. In this article, the possibility of increasing resolution in pixelated-LED-based optical modules towards DMD resolution level will be investigated, and its pros and cons will be studied. The challenges of making such HD modules will be discussed and the limiting factors, especially the ones regarding contrast and efficiency will be presented.