individual basis, using their own assessments
and judgements resulting from acceler-
ated testing methods and detailed
expertise.
As a significant part of
the reflective area in the
luminaire housing may be
occupied by the LED-carry-
ing PCB board or module, controlling
the variations in reflection of the PCB solder
mask has never been as critical for LED light en-
gine manufacturers, or for the PCB assembler.The
solder mask is stressed to the limit in thermal and
chemical processes like soldering, and this could
lead to problems controlling luminaire performance
and specifications over different production runs.
Achieving a reliable, sustainable and repeatable
reflectivity of the solder mask is thus not only
dependent on LED module manufacturers, but
requires an end-to-end alignment down the entire
supply chain.
Thermals
Another parameter requiring ongoing control during
the manufacturing process is the close connec-
tion of the LED boards to the luminaire. Managing
thermals is one of the key tasks for the luminaire
designer. However, production of the luminaire may
suffer from variations in flatness of the PCB board,
which if not clamped or screwed down properly,
can result in poor or intermittent thermal contact,
leading to reduced lifetime. On large LED boards,
warping, bow and twist, or tilting of the boards may
result in deviations in direction of the light.
Burn-in testing
The ultimate quality gate for functioning of the LED
light source is burn-in testing or switching on the
light source for several hours before shipping it.
This can lead to a tremendous test-factory set-up
and delays in factory output and costs if the test
parameters are not chosen correctly and sample
sizes and feedback processes are not managed
properly. Test-settings and test policy should be
based on knowledge garnered from ac-
celerated testing in the development
processes, flavoured with the learn-
ing curves built up over years of
experience with final testing across
various product families.
In a world where a high percentage
of LED light engine manufacturing is out-
sourced, it is important to consider the ca-
pabilities and oversee the quality processes
of the third parties selected. It is imperative to
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LiD
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