Automotive lighting has grown multi-fold over the years, with lighting systems assuming roles pertaining to safety, aesthetics, customisation and vehicle autonomy. Automobiles, in terms of technological evolution, have predominantly leveraged halogen lights that are still widely used, with newer technologies like HID (high-intensity discharge), LED (light emitting diode) and laser lights now coming into the picture.
The objective behind the evolution of automotive lighting is to reduce the amount of heat generated, while increasing the level of brightness or output. Another focus area has been on the constant reduction of power utilisation of overall lighting systems in a vehicle – from headlamps, turn indicators, brake lights, daytime running lights (DRL) to cabin interior illumination. Every new development in the field of automotive lighting has been achieving these key requirements, with the focus subsequently shifting towards other areas that the technology can assist in.
The leap in automotive lighting technologies is not limited to passenger cars and SUVs alone, but across all vehicle segments. With India currently being the world’s largest two-wheeler market, we are witnessing newer lighting technologies moving into this segment in recent times. Similarly, commercial vehicles are also beginning to adopt new-generation illumination systems, which enable improved visibility, better brand identity, safety and efficiency. It must also be noted that such low-power, high-benefit lighting technologies are a natural benefit for hybrid electric vehicles and battery electric vehicles, since their main focus is on efficiency and low power utilisation components.
In today’s automotive environment, it is easy to identify a brand of vehicle just through the design of its headlight, taillight or DRL, or even by the method in which its lighting systems work. Audi has been one of the pioneers in the modern era for automotive exterior lighting design. The carmaker was one of the first to bring in the LED technology into mainstream exterior lighting systems, with other companies following suit. An iconic design element that Audi brought in a large way to the automotive industry was the sweeping turn signal indicator, which flows towards the direction of turning, thus providing a more dynamic signal to other road users. All major OEMs currently have their own unique lighting designs that make it easy to identify a brand even in pitch dark conditions.
The need for custom lighting designs has prompted component suppliers to carry out development work, in terms of providing complete lighting modules that encase various parts that enable the final lighting requirements of OEMs. Designs of front, rear, side and ambient interior lights are also co-developed by Tier 1s and OEMs so as to satisfy the overall end-design of the vehicle. The development of such complete lighting modules has provided designers with far greater freedom in making vehicles with radical design elements, which would eventually help in fighting competition.
Interiors of vehicles also gain from the use of lighting systems, although quite differently from the basic function of cabin lights, which turn on and off as doors are open and shut. While this important function remains, interior lighting has evolved hugely to soothe the senses of occupants and provides a sense of relaxation and comfort through mild ambient illumination. A number of vehicle models with mood lighting feature are also provided with a certain level of customisation for occupants to select their level of comfort. In addition, passenger vehicles are typically offered with optional lighting that can be used during the journey for purposes such as reading or working.
SAFETY, DRIVER ASSISTANCE
It is interesting how lighting systems have developed to be much more than just components to provide additional illumination on the road. Even the operation of vehicular lighting has come a long way, with these systems having the capability to turn on and off automatically, without driver initiation. Sensors connected to the lighting systems understand the level of illumination or weather conditions and automatically switch on the lights as required. The lighting systems in present times also work with active safety systems of the vehicle in improving their performance, which then leads to increased levels of safety.
A simple safety or convenience feature of present day exterior lights is that they remain on for a while after locking the vehicle and then go off, in order to provide added illumination in dark parking spaces. A more innovative and technologically-advanced feature is that of Adaptive Lighting that makes use of LED technology. Adaptive lighting encompasses various automatic features that are present in a vehicle’s lighting system to enable improved vision for the driver as well as for other road users. It typically consists of cornering lights, automatic beam control and static turning lights. Cornering lights move in accordance with the movement of the steering wheel, thereby providing additional illumination to a section of the road, where the vehicle intends to move next.
The automatic beam control is a technology, where the headlight senses oncoming vehicles and pedestrians, and turns down the beam or adjusts parts of the beam away from them to avoid dazzling them. An LED headlight module is made up of multiple LEDs, and the automatic beam control has the ability to control each LED individually to produce the complete lighting distribution. Meanwhile, static turning lights or roundabout function is one where additional lighting is provided around the corners of the vehicle when reaching a junction, so as to provide the driver with added visual aid. This feature is connected to the navigation system of the vehicle, and turns on the lights just as the junction or roundabout is being approached.
Lighting systems help enhance vision-based safety systems that use cameras to monitor the road and either make active changes to the vehicle or warn the driver to do so. The lighting system in a vehicle works especially well with camera systems to detect on-road obstacles at night or in extreme weather conditions. There are certain lighting systems that are provided with the information of the presence of an object, and intimate not only the driver, but also the object (another vehicle, cyclist, pedestrian, animal, etc.) by flashing the light. Such warnings could also enable the vehicle’s automated braking system or other active safety systems to kick in and drastically-reduce the chances of a mishap.
Similarly, interior lighting technologies have also been developed to a large extent, where they can be used to warn drivers of imminent collisions or other warning inside the cabin. While the ambient lighting in a vehicle equipped with such technology remains soothing on a regular basis, warning for anything from vehicles in the blind-spot to obstacles on the road ahead can be provided with subtle flashing of a contrasting light. Such visual warnings could help decrease the reaction time of drivers, enabling them to swiftly take corrective actions. All these lighting features that are connected with safety systems in the vehicle show how strongly lighting complements safety – both active and passive. Safety systems serve as the basis for autonomous driving technologies, and therefore it is clear that lighting technologies will be a big part of a vehicle’s autonomy.
It is clear that the role of automotive lighting has progressed by leaps and bounds, with the infusion of a large amount of electronics and software. Lighting modules are no longer simple single-layer systems, but are multi-layer in nature due to their added functions. They combine lighting technologies, multiple control units, software programming and other technologies to provide appropriate illusion, while supporting several other styling and safety functions.
With such a large function to carry out, it is no surprise that apart from OEMs and Tier 1s, even semiconductor companies are foraying into the development function of lighting systems. Semiconductor manufacturers are developing chips that would enable automotive lighting modules to support all other requirements beyond lighting functions, and make them work together with other vehicle sub-systems.
Digitalisation of lighting, laser lighting technology and flexible Organic LED systems are some of the topics covered in this edition, talking about the various developments taking place in the area of automotive lighting.
(With inputs from Audi, Mercedes-Benz, Hella, Mouser Electronics, Volkswagen, Continental)
TEXT: Naveen Arul