For each new development we have increased our understanding of light, providing the stimulus for new solutions which deliver good, energy efficient, lighting for humans. A lot of the new findings have forced us to learn and re-think what we knew during the years.
Compact fluorescent lamp
In mid-eighties there was a new light source on the market, the compact fluorescent lamp. Suddenly we were able to make energy efficient lighting with smaller dimensions such as downlights and wall luminaires. It was an intensive light source and there was a lot of light that had to be taken care of. This little light source could have a luminance (light intensity) up to 40.000 cd/m2! Basically we had the energy efficiency of a fluorescent tube in a miniature size. The new light source suddenly became an alternative to the traditional bulb in a lot of applications and led to a whole new range of stylish fittings.
In the very first Pleiad downlighter that was released in mid-nineties we developed a symmetrical light distribution from a horizontally positioned lamp. Why horizontally? We simply wanted to keep the recess depth as low as possible since there often is a lack of space above the suspended ceiling. With a lot of engineering skills we designed a reflector with symmetrical light distribution with excellent cut-off from the horizontally positioned lamp! When others made cut-outs in the reflector for lamp switch we made a toggle solution for that in order to get the most light out of the Pleiad.
In the early nineties we also got the electronic, high frequency ballasts resulting in increased energy efficiency and a flicker-free light! At Fagerhult our big issue was controlling the heat on the ballast since heat kills electronic devices. After some years we introduced our own policy regarding thermal control and stated that we should always have at least a 5 °C margin to the stated TC-point on electronics.
The t5 led to r5-louvre
Another good example of innovation is when the T5 fluorescent lamp entered the market in the mid-nineties, making many of the norms of T8 luminaires irrelevant. One aspect was that the T5 tube performed at the best at an ambient temperature of 35 °C instead of T8’s 25 °C. Next thing was to decide what we should do with all light and how we should control it? The luminance in cd/m2 values rose about 50 per cent and compared to the T8 there where issues with glare from the new, highly intense light source.
The answer was to design totally new double parabolic louvres that were not only glare-free but also provided higher efficiency to the luminaire. The solution consisted of side and cross reflectors where the cross blades were designed with a sealed top that reflected the light back into the side and top reflectors which minimised the light losses. The curved tops of the cross blades eliminated unwanted reflections on the side reflectors and gave a good mechanical cut off in all directions.
To maximise the light output out of the luminaire we also made the cross blades thinner and that itself made the light opening’s area approximately 4 percent larger, resulting in higher efficiency.
LED revolutionised the lighting landscape; high light flows ensured superb efficiency and economy, with a lifespan of tens of thousands of hours.
From what was previously the domain of decorative accent lighting, LED technology evolved into a practical, general lighting option. To truly embrace the benefits of LED, and to address the demands it posed in issues of glare and heat management, required completely new solutions, rather than just changing the light source. The great challenge with LEDs is to keep glare within reasonable levels. It is not unusual that diodes and LED modules have a luminance (light intensity) of over 300.000 cd/m². In contrast, a standard T5 fluorescent tube has a luminance of 17.000 cd/m².
Again, we started from scratch, developing new luminaires specifically for LED, creating viable solutions across the whole spectrum of a lighting project.
LED’s greatest advantage is also its greatest challenge. Balancing efficiency with ergonomics. Combining good economy and lighting comfort. With our experience, lighting know-how and innovation we did just that .