Interview with the Osram experts Dr. Roland Fiederling and Dr. Markus Hessler
Why does halogen provide 110 percent more light and xenon 70 percent? What are the benefits of the new Osram Night Breaker unlimited? We wanted some precise answers and asked the Osram experts Dr. Roland Fiederling and Dr. Markus Hessler – our interview promises exclusive insights behind the scenes.
What has happened to halogen and xenon automotive lighting over the past few years?
In the entire after-market segment in recent years we have been adapting our products to the increasing demands by customers in terms of color temperature and lifetime. As a first step we managed to increase the lifetime of the Night Breaker significantly by upgrading to Night Breaker Plus. To improve the Cool Blue still further we worked on its coating. The new bluer coating on the Cool Blue Intense results in an even whiter light. The highly successful and robust Silverstar family now also has improved lifetime values so the new Silverstar 2.0 generation lamps now last even longer.
To make further progress in the high performance sector we first adapted the brilliant and highly attractive layer used on the Cool Blue Intense to meet the demands of the Night Breaker Plus family, and in spring last year we launched a Night Breaker Plus Limited Edition for H4 and H7. This meant that we were able to offer even whiter light for products in the Night Breaker family.
More recently, we also launched Night Breaker Unlimited. This features an improved coating and improved filament design. Compared with the Night Breaker Plus there are significant improvements in performance and light color. Thanks to all these improvements it was then possible to do without gold-plated contacts because by this time they would have had a negligible positive effect on performance.
There has also been progress in xenon lamps. For example the D8S has been developed. This 25 W xenon lamp has a smaller luminous flux than the previous 35 W models but therefore does not require automatic beam adjustment or headlamp cleaning system. These benefits can lead to lower-cost HID solutions in the mid-range segment, bringing a further benefit for customers.
What was the challenge in developing the Night Breaker family?
One particular challenge involved optimizing the performance because a balance had to be struck between high luminous efficacy, optimum luminance and long life. Considerable development work was needed to determine the right parameters for each lamp type and each filament.
The switch to the new blue coating for the Night Breaker Unlimited was also very challenging. The production requirements relating to the location and thickness of the blue layer are much higher than for the previous coating.
And what’s the partial blue coating all about?
The blue coating leads to an increase in the perceived light color and at the same time allows a filament adapted for high performance to be used. The range can therefore be increased further while still complying with statutory regulations.
To what extent do the statutory illumination values restrict further development?
The statutory requirements contain both lower and upper limits for output, the luminous flux and also in some cases the filament geometry. These requirements for the lamp ensure that a minimum illumination is guaranteed on the road and that there is no excessive glare. Within this framework there is scope for further development.
How many technicians, engineers, etc. are working on development?
At OSRAM the same high standards apply to retrofit products in terms of quality and performance as for OEM products. For this reason, a great many departments are involved in such further developments. These departments obviously include Development and Production, and also measurement and application facilities. In any case, there are many engineers and technicians involved in further development.
Will there ever be a limit to the further development of halogen and xenon lamps?
Further development of the halogen lamp will certainly not progress in such large strides as in the early days of halogen lamps. But there are always small details that we can improve, such as making the filament in halogen lamps more compact or shortening the arc in xenon lamps.
Why does halogen provide 110 percent more light and xenon 70?
The statements “up to 110 %” more light for Night Breaker Unlimited, and “up to 70 %” for Xenarc Night Breaker Unlimited relate to their respective comparison lamps. This means that the Night Breaker Unlimited provides up to 110 % more light than other halogen lamps available on the market, and the Xenarc Night Breaker Unlimited produces up to 70 percent more light than other comparable lamps on the market.
What does 110 % more light mean for drivers, where do I see the 110%?
110 % more light means that more light is projected onto the important areas of the road ahead. This leads to an increase in the range of the beam or its intensity compared with standard lamps. The greater range can best be seen by the distribution of light from a bird’s-eye perspective. The vehicle is shown in position 0 and the white area is the illumination on the road. For determining the range the illumination on the right-hand side of the road is relevant so that the lie of the road, traffic signs and obstacles can be seen in good time.
How can the light output be better if the wattage is not permitted to increase?
Good filament design enables the luminance of the filament to be increased for the same electrical power. Luminance is one of the crucial parameters of a filament in terms of increasing the range of the light beam. The longer beam of light from Night Breaker Unlimited is therefore the result of optimized filament geometry.
What are the benefits of improved light to me as a driver? (the changed light color)
A whiter light color, in other words one that is closer to natural daylight, makes drivers more alert. Lighting that is matched to natural daylight can stimulate the organism and help prevent fatigue and attention deficit.
And how do you produce whiter light?
To make the light color of a halogen lamp whiter (increasing the color temperature) the filament temperature must be increased. Alternatively, the red and green components in the light can be filtered out by appropriate coatings.
Is there a limit – when will Osram launch the lamp with completely white light?
The definition of “completely white light” is not a simple one. From a photometric point of view all headlight lamps are located in the white field defined by ECE regulations. The simplest way of putting it is to say that light with a color temperature of around 5500 K corresponds to that of the sun. In the case of halogen lamps it is possible to increase the color temperature further with the aid of filters but 5500 K could only be achieved at the expense of a considerable loss of brightness. In contrast, xenon lamps and LED lamps already provide very white light which is close to 5500 K.
Seeing better is important, and so too is being seen. How does Night Breaker Unlimited help in this respect and does more light mean more glare for oncoming traffic and pedestrians?
Increasing the performance of Night Breaker Unlimited causes a small increase in the proportion of white light in the light beam. This does not however mean that oncoming traffic or pedestrians will be excessively dazzled. What it does mean is that a vehicle equipped with Night Breaker Unlimited will be easier to see. In any case the lamps are designed to comply with all the prescribed values. In other words, glare for oncoming traffic and for pedestrians falls within the permissible thresholds. Irrespective of the lamp used, care must be taken when installing the lamp to ensure that it is seated correctly and that the headlights are properly adjusted for height. Dirty or scratched covers can also increase the glare effect.
To what extent does the vehicle itself impair the life of the lamps? Is there anything that can be done to improve things?
An incorrect operating voltage, particularly one that is too high, can shorten the life of halogen lamps. If you suspect that the operating voltage in the vehicle is too high you should have it checked at a workshop. You cannot do anything about it yourself.
What effect do headlights with diffusers, reflectors or projection systems have on the performance of Night Breaker Unlimited?
The use of Night Breaker Unlimited in different headlight systems may result in different levels of performance owing to vehicle-specific headlight versions (design, size, location).
How balanced is the compromise between lifetime and brightness for the Night Breaker Unlimited? And why is higher performance always at the cost of lifespan?
Luminous efficacy is the key to creating really bright lamps or high luminance values.
In simple terms.this is achieved by by higher filament temperatures, and higher filament temperatures lead to a shorter life. With Night Breaker Unlimited we have succeeded however in retaining the same lifespan despite a higher luminance compared with Night Breaker Plus. Night Breaker Unlimited is just as impressive in terms of its lifespan as the Night Breaker Plus. This means we have managed to reach an excellent compromise for the customer.
Our thanks go out to Dr. Roland Fiederling, Application Engineer Osram Automotive, and Dr. Markus Hessler, Development Engineer, Automotive, Halogen Development, for their open answers.