Since the first serial ADB systems developed by Volkswagen with vertical mechanical shadows, two other technologies have been proposed to find the best balance of performance, resolution, and cost.
First came the Matrix Beam on Audi’s A8 of 2013, followed by several systems using four to 16 segments per headlamp.
The second wave was launched in 2017 by Mercedes-Benz in the E-Class with three rows of pixels in one single module. In these technologies, increasing the number of pixels to a few hundred brought a lot of improvements in the latest car serial releases in the horizontal resolution, going from a few to 28 pixels on a row with the Mercedes E-Class.
DVN has kept on top of the progress, reporting on wonderful night drives with A8, TT, A7, A6, then E-Class, S-Class and others.
Those solutions offer an ADB mode wherein a complete vertical stripe above the low beam is switched off to prevent glaring the other road users. To improve the resolution for a better light close to oncoming cars and for road markings, we have seen several demo-cars (and now production cars, like the Maybach and e-Tron) with DMD technology.
Valeo, for their part, have developed another solution to improve the resolution. They call it PictureBeam, and it’s a lighting and road projection system.
PictureBeam Monolithic ADB – 4,000 pixels
The PicureBeam system provides a high-resolution (around 4,000 pixels) ADB with light all around the detected vehicles. It brings the function one step closer to being a real glare-free high beam, with a high accuracy in the cutoff position.
The technology is based on a monolithic LED, developped and produced by CREE, with 3,696 pixels to produce a high definition beam on the whole field. The main purpose of this module is to produce a high definition beam on the whole field. This module also makes it possible to do road marking for ADAS, but from 15 m in front of the car.
The 4-kpx Monolithic solution offers a resolution of 0.28° in both directions in the complete angular range of the high Beam, in order to keep a high-intensity light level everywhere where it is not dazzling the other road users.
With a 0.28° resolution over a full horizontal extent of 20° outboards and 16° inboards, this drawback linked with digital functions is now solved and the complete field of view where light needs to be finely adjusted is covered. Up to now, even with a high resolution, a dark shadow only consisting in 0% / 100% deactivation/activation of some pixels is perceived as a disturbing inhomogeneity in the beam (dancing light).
The module is composed of 4 major components corresponding to the main functions to be addressed:
– Monolithic light source to emit light
– Projection optics to project the light emitted by the source
– Cooling system to evacuate the energy emitted by the source
– Electronic board to drive and power the LED allowing driving each pixel individually.
Compared to other HD systems (like DMD or LCD), for which the luminous source itself is separated from the light spatial modulator, it is the most compact solution and most simple in terms of number of components.
The low beam delivers a flux of 1,250 Lm (with the flat module), a hot spot of 25 Kcd.
The high beam delivers a flux of 2,100 Lm with a hot spot of 75 Kcd.
PictureBeam Monolithic Road Projection
Road marking consists in projecting patterns on the road, with positive or negative contrast. These are to help the driver, as well as other road users, with mostly safety related features. They could be lane marking, highlighting certain areas, road signs projection, information displays.
Until now, most of these functions have been demonstrated with projection units using hundreds of thousands of pixels, like DMD or LCD technologies, and barely with discreet pixelised light source.
PictureBeam Monolithic Road Projection is based on a monolithic LED with 1,232 pixels to project elements on the road. The solid angle covered by this module roughly corresponds to the solid angle covered by a DMD module. This module also, participates in the ADB.
The weather was fine, but maybe too many
cars on the road with advantages and disadvantages.
The headlamp is equipped with three modules;
– The module which gives a flat light to have large light close the car
– The PictureBeam Monolithic Lighting based on a monolithic LED with 3 × 1,232 pixels to produce a high definition beam on the whole field
– the PictureBeam Monolithic Road Projection GEN1 based on a monolithic LED with 1,232 pixels to project elements on the road. The solid angle covered by this module roughly corresponds to the solid angle covered by a DMD module.
The first feeling, I never have had in all
the former night drives with ADB, is that the PictureBeam is a real high beam.
Only the opposing car is shadowed out.
The second important feeling is the perfect dynamic homogeneity. The dynamic homogeneity is a key element, to avoid to distract the attention of the driver. The full digital adjustment of each pixel intensity of the 4-kpx module allows perfect dynamic homogeneity in all situations. The glare-free area is finely vertically adjusted, so that there is no potentially disturbing projection of bright-dark contrast lines, and that the surrounding of the glare-free area is lit. This is only achievable with a high number of pixels. The dancing light I objected to in other lights I’ve assessed, is absent in this light.
What about the new assessed functions?
Few of them are interesting :among the several functions presented:
– One of the most important function made possible by HD Lighting is the Lane Marking or Construction lines which can be done either with positive or with negative contrast.
Different shapes are also available, with either stripes reproducing the
road marking lines, or a complete “carpet” in front of the vehicle, or even “2D
Lanes” with also transversal stripes, for example, to provide distance
This function was not useful in this night drive but I think it is one of the most important fuction about road marking
– The second interesting function is the projected arrow located at the exact location of the exit, with dynamic positioning upon the vehicle speed. This can be also used in advance, to help the driver to be positioned on the right lane, before a direction change on the motorway. In that case, a more simple message than an arrow, or a simple light movement, can be helpful. It can also be helpful to reduce the risk of confusion when the driver can use several directions: case of complex motorway exit or of many roundabouts.Other possibility for arros are for example the replication of Turn Signal, with clear arrows.
– Projection of a sign
The sign on the road could alert the pedestrian of a potential danger. It could be a line on the ground, simulating a “do not cross line”, or a simple halo, or a flash on the lower body area of the pedestrian.
Safety distance projection
“When the vehicle is getting too close from the leading one, alert messages as simple as highlighted zones or a series of transversal light bars could be used. The setting of these bars, as well as the projection distance can be defined by the user, while their activation can be coupled with the front radar or lidar.
“Less important for me is the information are road signs display, after their reading thanks to the front lighting camera, or information coming from the vehicle, such as external temperature display, or risks of icy road.
They are also a direct redundancy to images which are usually set on the HUD, In the end, displaying these signs on the road is not suitable, should be and could be replaced by information on HUD,
This night drive shows not only the
fantastic job done by lighting industry these last 10 years since the arrival
of LEDs, but more important the huge challenges in front of us about the
resolution, resolution further than 30 m away to improve light and resolution
from 0 to 30 m for road markings.
“You will have more information after the next night drives with AL and then with Hella and ZKW before night drives with the last coming cars in production.”