Digital projection headlights are a new task for car lighting. Whether interacting with passengers inside the car or people outside, they provide a great sense of interaction. Currently, there are 3 relatively mature projection headlight solutions.

Digital Projection Headlight's DMD Solution

DMD is currently the only mass-produced digital projection headlight technology. The DMD-type light source system can be understood as a projector using only white pixels, with no fundamental difference in basic principles. Of course, to meet automotive regulations, especially the stringent usage environments in projection headlights, both the DMD device and the accompanying optical system have been optimized in design. Additionally, since the headlight projection surface is horizontal, the trapezoidal distortion effect of the projection image becomes more apparent with increased projection distance, necessitating corresponding image algorithm corrections.

Overall, compared to other current digital projection technologies, the main advantage of DMD lies in the vast number of pixels. The first DMD headlight has already surpassed the million-pixel mark, leading other technologies by a large margin, with further potential for future improvement.

Digital Projection Headlights's LCD Solution

Removing the three-color filters (RGB Color Filter) not needed for car lights, LCD-type headlights are similar to ordinary LCD displays, requiring basic components such as a backlight source, polarizer, and liquid crystal panel.

Additionally, due to the much higher power density compared to regular LCD monitors, the significant heat generated by the LED matrix backlight prevents the liquid crystal panel from being placed directly on the backlight source like in an LCD monitor. Secondary optical components like reflectors need to be added to form a certain distance in the light path.

Even so, due to relatively higher brightness, the polarizer and liquid crystal panel must absorb much more light loss compared to ordinary LCD monitors. Combined with the need for rigorous automotive-grade validation, these components, particularly the liquid crystal panel, must be specially customized by manufacturers.

Currently, the pixel level of LCD-type projection headlights has reached tens of thousands. Given that current LCD technology for displays can achieve much higher pixel levels, it is reasonable to believe that LCD headlights can break through to a hundred thousand or even higher pixel levels in the near future.

Digital Projection Headlights's Micro-LED Solution

In traditional LED technology, each chip only had a single anode and a single cathode (multi-chip LEDs only integrate multiple independent LED chips into one LED package), and the entire chip illuminates simultaneously when external power is provided.

Micro-LED integrates a matrix of CMOS control circuits within the chip's silicon substrate beforehand. With a chip matrix structure, it allows individual on/off functionality and current adjustment for each micro-structure area on the chip, making each micro area a controllable pixel in the headlight beam pattern.

Therefore, although Micro-LED still uses LEDs as the light source, the differentiation from LED-based LCD or DMD headlight systems lies in pixel formation, Micro-LED directly forms pixels on the LED chip itself, while LCDs form pixels through a liquid crystal panel and DMDs through microlenses.

Thanks to the lack of additional pixel generation systems, the main advantages of Micro-LED are lower system cost, smaller system size, and significantly higher efficiency. These three characteristics make it possible to use multiple Micro-LEDs in combinations to form more complex optical systems.