SSL | HD Matrix LED lamps: Interesting facts, repair instructions and practical tips

Here you will find valuable and useful workshop tips on the design, function and diagnostics of the SSL | HD Matrix LED lamps.

Light on the road is going digital. This means that, in future, light distributions will be brought about primarily by means of digital control of high-resolution light modules. As a result, new and diverse application possibilities come into play, one of which would be, for example, the ramping up of road safety

Important safety note
The following technical information and practical tips have been compiled by HELLA in order to provide professional support to vehicle workshops in their work. The information provided on this website is intended for use by suitably qualified personnel only.

SSL | HD Matrix LED lamps: BASICS

Light on the road is going digital. This means that, in future, light distributions will be brought about primarily by means of digital control of high-resolution light modules. As a result, new and diverse application possibilities come into play, one of which would be, for example, the ramping up of road safety. The Solid State Lighting-High Definition (SSL | HD) Matrix module with Liquid Crystal HD technology enables fully adaptive light distribution to suit the relevant traffic situation. The new LCD lamp projects light onto the road with more than 32,000 pixels. This allows the light pattern to be adapted intelligently, continuously and in real time to various driving situations. The following information is presented using a Porsche HD Matrix LED main lamp as an example.

Design and function: FUNCTION

In this LED lamp, four light modules with almost square lenses are arranged on a lamp holder. Two HD modules for the low beam and high beam light functions are mounted in the lower section. Each of these HD modules contains an identical LED array with 16,384 micro-light-emitting diodes, an array which generates a high-resolution luminous flux on a surface area of just 12.8 x 3.2 millimetres. The brightness of the LED array can be adjusted in more than 1000 steps or levels via the system control. And each HD module is equipped with a specially adapted lens having specifically ground optical glass, which creates different illumination angles.

The outer module with wide-angle lens covers an angle of 40 degrees in width and 10 degrees in height. The inner module, on the other hand, is equipped with a telephoto lens and covers an angle of 20 degrees in width and 5 degrees in height. Although the illumination range is only half that of the outer module, it is nevertheless much brighter. As a result of the overlapping of the light distribution of both HD modules, wide illumination with high intensity is achieved in the central area.

With over 32,000 individually controllable pixels per lamp, the HD modules generate high-resolution light that is projected only where it is needed thanks to this kind of light distribution. The pixels in each individual lamp are controlled by their own electronic control unit, which HELLA, as a system supplier, has also developed. Against this backdrop, so-called GMSL (Gigabit Multimedia Serial Link) interfaces are being used for the first time because of the high data volumes involved.

Special algorithms have been developed to control two light sources in a lamp with one control unit, thus enabling the light distribution to be calculated in real time. Consequently this system illuminates an area of 40 degrees horizontally and 10 degrees vertically with a luminous flux of over 1,400 lumens, thus creating one of the largest and brightest high-resolution illumination areas.

The illumination begins just in front of the vehicle and covers the entire high beam range. The amount of light required in each case can be distributed in this area as required and this flexibility enables existing light functions to be improved.

Two identical Bi-LED function modules are mounted in the upper area; with their six powerful LEDs, these see to the illumination of the area in front of the vehicle and they are also responsible for the auxiliary high beam. The individually switchable and dimmable light is projected via precisely ground and polished lenses. Furthermore, a light strip for the functions of the daytime running light and for the position light is mounted on the lamp holder above each of the four modules. If the lamp is viewed from the front, the four-point design typical of the brand can be recognised both in the day and at night.

Light functions

In addition to the basic light functions such as low beam or high beam, extra functions can also be displayed in order to assist the driver

Begrüßung und Verabschiedung 

Welcome and goodbye

The LED lighting in the lamps provides additional visibility and safety when the vehicle is opened and closed. When the vehicle is opened, a brand-specific animation is generated by the HD modules and projected onto surfaces opposite. After the ignition is switched off and the driver leaves the vehicle, the animation takes place in reverse sequence

High beam with auxiliary high beam

The auxiliary high beam is activated if the system does not recognise any vehicles in front or any oncoming vehicles when the automatic high beam is switched on. In this case, the two function modules are added to the two HD modules that have already switched from low beam to high beam. This increases the amount of light from 1,400 to 2,500 lumens and the road can be illuminated over a distance of up to 600 metres. The auxiliary high beam is switched off automatically as soon as vehicles in front or oncoming vehicles are detected.

Glare-free high beam with auxiliary function

The auxiliary high beam is deactivated as soon as a vehicle in front or an oncoming vehicle is detected by the vehicle camera. At the same time, the illumination area around the other vehicle is blanked out by the switching off of the relevant pixels. The light energy released as a result is converted into additional functional HD light so that the amount of light on both sides of the gap is doubled, and this ultimately leads to a visible brightening of the remaining high beam area. In this way all of the available HD light continues to be fully utilised in order to optimise the illumination of the road and thus improve visibility for the driver.

Lane assistant for lane narrowings

This function visually projects the width of the vehicle, including the wing mirrors, onto the road for the driver, for example on a roadworks site. This allows the driver to assess whether overtaking would be possible in such a situation. Road safety is consequently improved as both speed and also any correction to steering are then minimised.

Lane brightening

This function is only activated on motorways or comparable roads and serves to improve the illumination of the driver’s own lane. Regardless of the vehicle position, the carriageway between the lane markings is considerably brightened up in the form of an illuminated carpet. The illumination is extended to both lanes as soon as a lane change is being carried out and the lane marking is crossed. Once the lane change is complete, the illumination is adjusted and set to the current lane on which the vehicle is travelling. This allows the driver to recognise objects and hazards at an early stage and to react to a lane change carried out without due care and attention.

Adaptive motorway high beam

In this function, the system control ensures the best possible illumination of the road on motorways or dual carriageways and at the same time adapts the light distribution individually to suit the particular conditions prevailing. At the same time, illumination towards the centre of the road is displayed as a soft transition so as to avoid unnecessary dazzling of oncoming traffic.

Communication in the vehicle: Interesting facts

At the rear of the lamp mounted on the housing cover, there is one control unit each for the SSL | HD modules and for the modules lighting the road immediately in front of the vehicle.

The main task of these light control units is to control and monitor the individual light functions of the lamp. As well as the central controlling of all light functions, additional coordination tasks are also carried out, such as the dynamic adjustment of light distribution in adaptive lighting systems tailored to suit the individual driving situation. Internal vehicle communication is achieved by networking the lamp control units with the control unit of the vehicle electrical system and also by linking up with the control units of the individual driver assistance systems via the databus system. The light control units communicate via databus and thus receive data that is constantly and reliably implemented into the required light distribution. Depending on the vehicle model and system equipment, the networking structure may operate differently.

Service and repair instructions: Troubleshooting

Causes of failure and effects

A functional failure of the LED lamps can lead to the following effects:

  • Fault lamp lights up (system-dependent)
  • Fault entry in the relevant lamp or system control unit

The following causes can then be considered:

  • Faulty power supply
  • External damage or mechanical defects
  • Communication and bus systems faulty
  • Failure of lamp electronics
  • Defective control unit
  • Defective fan motor in lamp

SSL | HD lamp: Diagnostic information

The SSL | HD lamp and the rest of the vehicle lighting are monitored by higher-level control units in the vehicle system. Any errors occurring are stored in the control unit’s error memory and can then be read out by using suitable diagnostic devices. Depending on the vehicle model, the driver is informed of a system error by an extra warning appearing on the instrument cluster.

Lamp adjustment: Practical tips

After the following types of repair work, the SSL | HD lamp has to be readjusted.

  • Repairs in which a lamp was removed and then mounted anew
  • Repairs or adjustments that have an influence on the vehicle height or level
  • after replacing the following components: vehicle level sensor, control unit for vehicle electrical system, actuator for height adjustment, light control units for SSL | HD modules or modules for road immediately in front of vehicle

Before the lamps are adjusted, the following vehicle requirements first have to be met:

  • The vehicle and lamp adjustment device stand on a level surface
  • The parking brake is released and the vehicle is secured against rolling away
  • Tyre pressure is OK
  • The lamp cover lenses are clean and damage-free
  • The steering wheel is in the "straight-ahead" position
  • The correct vehicle level is guaranteed. Vehicles that were previously raised must be lowered to the normal suspension level.
  • The vehicle load has been checked and, if necessary, adjusted to the load specified by the manufacturer
  • The battery voltage is greater than 11.0 volts
  • There are no error entries in the system-relevant comfort control units.

In order to adjust the lamps, a diagnostic device is also required as well as a lamp adjustment device. The diagnostic device is used to begin headlamp adjustment, work which is performed by following the specified procedures. If the vehicle is equipped with levelling control, the suspension must be set to normal level and the control deactivated before adjustment is carried out. After a successful setting, the control function is reactivated.

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