Automotive ground projection headlamp, since its inception, it has attracted the attention of a large number of young people. The patterns projected at night not only function as a way to locate the car and illuminate the road ahead, but their unique logo or patterns can also highlight the owner's identity and enhance the nighttime welcoming effect. With the advancement of technology, it has also been endowed with more functions such as signal indication and information interaction.

Automotive ground projection headlamp usually installed on the welcome pedal, exterior rearview mirror, and other parts. According to different imaging principles, we divide it into three types: film lens type, MLA type, and DLP type.

Film Lens Automotive Ground Projection Headlamp

Film Lens automotive ground projection haedlamp relies on the principle of lens imaging, similar to a film projector. It usually consists of a concentrating system, film lens, and imaging system. It projects the pattern on the film lens, magnified, onto a specific area.

The earlier used PET-based film lens utilized the imaging and photography principle of a film camera, exposing the LOGO pattern onto the film lens. Due to poor heat resistance and aging performance, it has now been largely replaced by glass film lenses. The patterns on the surface are magnified dozens to hundreds of times through the imaging system. Any small defect on the film lens will be greatly amplified and displayed, thus, the tolerances of the automotive ground projection headlamp must meet very strict requirements, reaching the micron level to ensure that the projected pattern is free from defects and deviations.

The film lens type automotive ground projection headlamp is compact in structure, reliable, with clear patterns and low cost. However, the projected LOGO/ pattern depends on the picture processed onto the film lens, and this pattern is fixed and unchangeable. Therefore, the projection cannot be updated nor can it achieve dynamic effects.

Microlens Array Technology (MLA) Automotive Ground Projection Headlamp

The projection lighting assembly based on MLA consists of an LED light source, collimating lens, and microlens array.

The imaging principle of MLA is to project the image corresponding to each small lens in the microlens array onto the same position on the ground. For example, in an MLA composed of 64 microlenses, the observed image is actually 64 overlapping projection images, with the key being perfect superposition. Implementing this working principle introduces considerable technical challenges. Even when projecting onto a flat, vertical screen, the refraction angle of each microlens from a single light source within the array will vary slightly. Therefore, each microlens needs to be minutely offset from each other, requiring precise molding and positioning of each microlens to achieve nanometer-level manufacturing, so as to project a single sharply focused image onto a surface at a certain distance from the projector.

The lighting area of any given MLA assembly and image is also limited. However, the illumination area can be expanded by parallel installation of multiple MLA-based automotive ground projection headlamps, with the edges of one projection image overlapping with another. In this case, separate sliding masks must be created for each projector's lens array, increasing the overall cost of the projector system. This multi-mask projector system can be used to create 3D and dynamic effects.

MLA projection technology can also realize communication from vehicles to drivers, vehicles to vehicles, and vehicles to pedestrians by projecting icons and signal lights, making it a relatively low-cost solution.

DLP Projection Technology

DLP technology is a hot projection technology in the automotive lighting industry. The advantages of DLP are very obvious, comparable to installing a mini projector with full color, full dynamics, OTA upgrades, and customization, making it the future development direction of automotive ground projection headlamps. The only issue that needs to be resolved is the cost.

Automotive ground projection headlamp, as a configuration that can enhance the sense of technology and ceremony of the car, brings customers quite intuitive and obvious advantages. It caters to the needs of contemporary young people and will increasingly become an option in car configurations.