Directional DRLs may be the next lighting technology improvement, and they open myriad new design possibilities too.
Headlight design has seemingly reached its peak, with adaptive multibeam laser-enhanced lighting technology, LEDs everywhere, and intricate daylight running lamp designs representing the current state of the art. But, while this is as good as it gets at the moment, a new BMW patent discovered by CarBuzz at the German Patent and Trademark Office (DPMA) shows another possible evolution in lighting technology.
This patent applies to the daytime running lights (DRLs) and side marker lights and may soon appear on mainstream BMW models like the iX3 or next-generation BMW 5 Series and may also eventually spread across the entire BMW range. What makes this specific patent so appealing is that it doesn't rely on electronic control or electric actuators at all but is instead a passive system that modifies light beam intensity and direction in predetermined directions. This will cut glare from the DRLs without compromising the car's visibility to other road users.
Current LED DRLs only light up in the pattern with which they are designed by the engineers. This pattern is determined by the shape of the LED light guides inside the headlight units and effectively has a near-180-degree light distribution: No matter the onlooker's vantage point, they are almost always visible from all angles. This is both a good thing and a bad thing because, while the vehicle's visibility to other traffic is enhanced, these lighting units also have the potential to create glare for other road users if the DRL elements are bright enough to be fully effective.
BMW's novel idea is to mask the DRLs with an opaque shield inside the headlight lens assembly (item 11 in the patent drawing). These shields are created by coating a clear plastic screen with reflective metal using a PVD (Physical Vapor Deposition) process, which leaves a thin, impenetrable metal film on the shield.
The shields slot between the DRL elements and the outer lens and are capable of preventing any light from shining through the PVD coatings. Note that these coatings in no way alter the lighting emissions of the indicators or main headlight beams because the sections of the shield in front of these main lighting elements remain completely transparent.
Now comes the clever part. Through an automated process similar to laser engraving, thousands of tiny exit points can be created in this coating on the masking shields, which allow light from the DRLs to shine through these microscopic openings. But, because the shields are positioned very close to the actual DRLs, no light escapes upwards - only sideways and/or forwards. And depending on the angle at which the exit points are laser-engraved, the emitted light can be guided in different directions to accommodate the different requirements for side marker lights and DRLs.
Instead of the DRLs shining in all directions at the same brightness, as is currently the case, they will be perfectly visible in the horizontal plane from the front but become progressively less visible as the vantage point moves out of the desired light direction. Simply put, with their light emissions filtered directionally through the shields, the DRLs will be more visible from the front of the vehicle but dramatically dim as the viewpoint moves upwards or to the side of the vehicle.
The same principle applies to the side marker lights, which will be less visible when viewed from the front, but shine at full brightness when viewed from the side and from elevated vantage points. An added bonus is that the exit points in the DRL light shields can be placed and angled to allow for interesting 3D patterns without changing the physical shape of the DRL elements themselves.
The shields can also be coated with a body-colored film to aid the visual integration of the headlights into the vehicle's body, allowing the stylists yet more opportunities to differentiate various models or create a family identity for the front light signature. Think of how gorgeously detailed the laser lights on the rear of the M4 CSL are, and now imagine the same sort of intricacy being applied to the front lighting fixtures. That will add significant drama to a design, something that BMW seems to be aiming for with every new release.
And because these shields will be comparatively inexpensive to produce and require no moving parts, manufacturing- and accident repair costs can be contained. They may even act as an extra layer of protection for the expensive laser or LED main beam reflectors in the event of a rock striking the headlight cluster.