Spotted in Droxford, Hampshire a heritage lantern using the Philips Fortimo LED system.

The Fortimo system is what is termed a COB (chip on board) LED, where multiple LED chips are placed close together on substrate. This allows a larger lit area and in theory more lumens per given area than discrete LEDs.



Philips has used the Fortimo technology for well over 12 years in lanterns. Compared to discrete LEDs with lenses - such as the Stella which was manufactured at the same time - it had the potential to offer a brighter light source. However in practice the Fortimo lanterns were rather disappointing in terms of light level - at least those seen by Sotonsteve and myself.

As LED technology moved on, the performance from discrete LEDs improved and they are the mainstay of current lantern design.

Ironically Fortimo now gets a lot of coverage on the Philips webpage and at least for them seems to be making a comeback, especially for commercial and industrial ceiling lighting where the "solid" strip of light can be used for architectural purposes.

The first generation Fortimo installations in heritage lanterns in Southampton in 2008 were crap. They were about half the power consumption as 80W mercury (at 45W), but the light output on paper was also about half in terms of lumens, and in reality was easily half as dim.

However, the next generation Fortimo with the "Toblerone" that came out a year or two later was much brighter and more efficient. Many of these were installed in heritage lanterns in the Southampton city centre parks. Recently almost all of them in Hoglands Park have been replaced by different LED lanterns for some reason, but they currently remain in the other parks.

One failure mechanism is that the phosphor can become worn or damaged, and you end up with the white light becoming blue! I haven't seen this in Southampton, but on the Koffer2 lanterns on Westminster Way adjacent the A34 in Oxford, which also use this system, I've seen a couple that have colour shifted this way. I've seen pictures of lanterns in the USA that have had worn phosphor and the lighting turned blue too.