If someone mentions automotive lighting, our thoughts would probably initially jump to headlights where there has been very visible, ongoing innovation. Maybe after that we’d think next of the running lights and taillights where manufacturers often use unique designs to strengthen their brand. It would probably take some time before you think of the general ambient lighting in the car. But ambient lighting can have some really important effects on the occupants of the car psychologically, especially after a longer period of time. The ambient lighting of the car cabin can affect the mood of the passengers and driver.
Ambient lighting is more than instrument backlighting; it is the entirety of the interior indirect lighting in the car. The lighting is intended to provide the driver with positive emotions, such as relaxation, safety and pride, as well as making him or her feel comfortable and stop any feelings of claustrophobic in the driving position. The internal ambient lighting supplements the exterior lighting in an attempt to minimize any tiredness while driving.
Each vehicle has a variety of internal lighting that combines in the overall ambient light. Backlighting for displays, instrument indication and running lights all contribute to the overall effect. The quality of ambient lighting has a proven effect on how we feel when we drive and can have a positive impact if implemented correctly.
Figure 1: Ambient lighting is now incorporated into innovative turn- and brake-lighting applications, backlit displays, occupancy detection, night vision, and more
Psychology of Lighting and Color
It has long been known that lighting has an effect on how we feel. In the home or workplace, lighting affects our moods, our productivity and our decisions. Whether the light is warm or cool has a noticeable psychological affect that can make us feel tired or awake. It can affect our circadian rhythms and moods. Bright white light is seen as clean and may be used in environments like kitchens to give a feeling of hygiene. Warm yellow light can make newly baked cookies seem more appetizing, or can make you feel more relaxed at night in the bedroom. Manufacturers of automobiles have also tested lighting colors to determine which ones make drivers more relaxed and attentive.
Light is often used to provoke different emotions. It is a subject that has been studied extensively. BMW engineers and the Lighting Engineering Group at Ilmenau University of Technology in Munich looked at this phenomenon in an automotive interior lighting study in 2009. Participants in the study drove in a simulated environment where the ambient lighting was changed in position, color and brightness. After the simulation was completed, participants were questioned on how they felt, and their emotional state was measured at the beginning and the end of each test.
The study looked at a large variety of different factors that may have an impact on the emotions of the driver. As well as the color of the lighting, the study looked at the shape of the lighting and the materials that made up the lighting installation. It also looked at the feelings that the lighting designs intended to convey – a feeling of luxury, or sport for example. Some of the participants were tested with either blue or orange lighting. Each of the two color had benefits and drawbacks. For example, blue lighting made it easier for drivers to navigate the interior of the vehicle. Instruments were easier to see and controls easier to find, which gave the driver a better feeling of orientation. The major downside to the blue lighting was that it made the participants feel uncomfortable. The orange light had a completely different effect on drivers – it gave them the perception of luxury and quality. With both test lighting colors, participants became more distracted when driving as the intensity increased.
Figure 2: The OSRAM OSTAR Headlamp Pro LED has scalable brightness, adapts to ambient conditions, and mounts many ways, including soldering to a flexible printed circuit board as shown
The survey results also found that ambient lighting was very important in its ability to reduce driver fatigue and therefore increase safety while driving at night. The tests also found that well-designed ambient lighting could foster appreciation of the vehicle, while enhancing positive feelings for the brand itself. Good ambient lighting could make the driver feel the car was roomier and built from better quality materials.
Benefiting from Interior Ambient Lighting
Today, especially in higher-end vehicles, ambient lighting is designed by manufacturers to almost become a fashion accessory. Vehicles from major manufacturers, such as BMW, Audi, Cadillac, Jaguar and Mercedes-Benz boast scientifically optimal lighting that is designed to enhance the brand, while giving the best possible experience to the driver. Lower-end manufacturers are also starting to implement some of the lessons learned from premium manufacturers.
LED ambient lighting today has evolved from what was once purely cosmetic to improve the look and feel of a car’s interior and make the car “feel” that it is better quality, to an integral part of the car’s safety features. The ambient lighting can be set up to assist the driver when entering or leaving the car, easily see and activate the controls of the vehicle, while also helping the driver feel more relaxed.
Of course, that is not to suggest that ambient lighting is merely cosmetic, it must be functional as well. For a designer, there are other aspects to consider in the design, such as the optimal number of lights and what the lighting will look like, both internally and externally. How can the lighting keep the driver alert, without feeling strained? Can he/she locate and apply the controls easily?
Applications
LEDs are the main luminaire used in vehicular lighting design because of their long lifespan, low-power use, flexibility and huge range of coloring options. These lights can be found in the roof light, behind instrument and display panels, in the controls and switches, and even designed into door panels to provide the lighting for the driver to enter or leave the vehicle.
There have since been many studies on every aspect of ambient lighting on emotions and perceptions in both vehicles and buildings, but the one mentioned earlier by BMW in 2009 remains the most comprehensive to date. This research has provided the most data for manufacturers on the psychology of automotive ambient lighting. Many other automotive manufacturers also use LED ambient lighting to make their own offerings stand out. Taking the lead for user customization is Mercedes Benz. The company’s high-end vehicles can offer customers a choice of seven different colors, five dimming levels and four dimming zones.
LEDs have revolutionized almost every area of car lighting, most predominantly, so far, in headlights. As well as giving the inherent advantages we expect from solid state lighting, such as longer service life, higher efficiency and higher reliability, LED headlights provide a range of new features that can improve safety for drivers at night. This flexibility externally also transfers to interior lighting as LEDs are far easier to control than incandescent lighting. Their much lower size and weight also means that implementation of LEDs are simpler and they can be mounted with standard fixings such as clamps or adhesives – in fact in any way that allows any thermal build-up to dissipate evenly. LEDs are also evolving themselves, with new materials opening up new applications for vehicles. Galium Nitride technology, for instance, now allows LEDs to operate at greater efficiency and at higher temperatures.
LEDs have had a profound effect on lighting in vehicles. These advantages are both in the large range of options that were unavailable using previous technologies, and in the degree of flexibility and control that they have given automotive designers. LEDs for interior use have presented designers with a choice of colors, brightness and intensity than ever before, while allowing them to account for changes in the environment. External lighting applications have also brought a huge amount of choice to designers for high power LEDs in a wide variety of colors. To give an example from one manufacturer, OSRAM Opto Semiconductors manufactures a wide range of LEDs and LED modules in precise color options. According to the manufacturer, the company’s OSTAR Headlamp Pro, “The color coordinates of the LEDs correspond to the white field of ECE/SAE, in which the red component of the LED is greater than 5%.…”. These LED advances have allowed designers to tailor light to specific needs in repeatable ways, never seen before.
The Future
There is no doubt that future research will continue to make more advances in the field of lighting psychology, and that research will be translated into real-world technology that will further advance the safety and aesthetics of vehicles. Future research will continue to focus on how lighting color affects our moods and perception and how much ambient lighting can influence ordinary driving tasks, such as navigation. Advances in connectivity and the Internet of Things will also offer more automated adjustments to ambient lighting, ensuring it is constantly optimal for the environment in which it is operating.
We know from research that ambient lighting has a large effect on human emotions, and we can use that research to produce precise and repeatable solutions that also enhance safety. At the moment, manufacturers assume that the driver will make the decisions that impact his or her concentration, such as turning off distracting lights. In the future, these adjustments will be made automatically. Automatic adjustment will also be used for other tasks, such as maximizing efficiency, or to adjust the ambient lighting accounting for the driving environment. For example, if an airbag is deployed, the lighting may adjust itself to full brightness in case the occupants need to leave the vehicle quickly. Automated ambient lighting could also preserve battery life by dimming lights if the vehicle was running on battery power alone.
Smartphones may be used to store preferred pre-set profiles for different drivers who may use the vehicle, or to adjust the lighting on instructions from the phone’s GPS. We can only imagine the improvements that could be implemented further in the future as devices get smarter and LED technology advances. One thing is sure, there is no sign of the advancement of creative ambient interior lighting for vehicles slowing down.
