Letter to the Editor: White LEDs fail to match hype

A lighting designer and specifier explains why he has stopped using white LEDs.

[Comment on this issue via our Blog entry "White LEDs fail to match hype".]

Dear Sir

As an exhibition designer and lighting specifier I have been a keen advocate of white LED lighting in exhibitions, but recently I have had to reconsider this decision. There is an urgent need for the white LED lighting industry to develop a more transparent and meaningful framework for the specification and performance rating of white LED-based lamps.

If this is not done then I believe that many of the developmental gains of the last few years may be squandered as users are put off by the poor performance of some products.

High failure rates and very rapid phosphor degradation has made manufacturers claims of 50,000-hour lifetimes seem, at best, grossly exaggerated hyperbole and, at worst, deliberate deception.

A recently surveyed exhibition, containing 48 GU10-base lamps, revealed that in 2500 hours of operation, light output had fallen by between 82 and 87%, while 12% of the lamps had failed electronically.

Given that the purpose of a lamp is to provide useful light, while the LED emitters themselves may well function for the 50,000 hours claimed, the actual life of a lamp is determined by the useful phosphor life, which does not even begin to approach this figure.

In reporting this sort of performance to suppliers I have been surprised at how little they know about the true performance of the products they are selling. As white LED lighting becomes more prevalent it will be distributors and retailers that will bear the brunt of customer dissatisfaction and may well fall foul of advertising standards regulations.

It is only market pressure that will force manufacturers to specify their products more transparently and direct resources into solving these challenging problems.

In the meantime I have been forced to replace whole lighting systems at my cost and consequently I have had to take the decision to not specify white LED lighting until such time as I can be confident in the specifications and lamp life.

Unless the true performance of white LEDs can be dramatically improved or costs substantially reduced then this technology may yet prove to be a dead man walking.

Frazer Monks
Exhibitas Design
Newport on Tay, Fife, Scotland
Email: Frazer Monks

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