Hydraulikpresse - Hansa Flex

fascination technology faszinaTion TecHnik
HiGH illuMinance led TorcHes These days, leds are
used in much more than just pocket torches, they are also
found in all kinds of signal and street lights, even in vehicle
headlights.
watt bulb, they consume barely 8 watts.
further advantages of leds are their long
service life, freedom from maintenance,
low energy consumption, colour stability and
impact resistance.
light emitting diodes are referred to as electroluminescence
radiators. they are based on semiconductor
connections. they are powered by a low voltage and
there are usually several diodes in a module. for led
light in conventional lamps, the lighting industry offers
rgB led modules, which are housed in a light
source in the shape of a light bulb and have an e27
screw-in base. in a “normal” residential light fixture,
they can emit white light for general and area illumination,
or coloured, atmospheric lighting in red,
green and blue as desired.
HoW iT all beGan
be explained for another 60 years. in 1907, henry
Joseph round was the first person to observe that
inorganic substances are capable of emitting light in
response to an applied voltage. in 1921, the russian
physicist oleg lossew rediscovered the round effect
and investigated it in detail until 1942. he supposed
that the phenomenon could be characterised as a reversal
of einstein’s photoelectric effect. then in 1951
georges destriau discovered a similar illuminating
phenomenon with zinc sulphide, and he named it
lossew light in honour of the russian physicist.
when the transistor appeared in 1951, it drove
scientific advances in semiconductor technology.
after 1957, semiconductors were the core element
in researching light generation. there is still some
argument about who really invented led lighting.
according to some sources, the light emitting diode
was invented by nick holobyak in 1962.
the origins of semiconductor development lie in
a scientific discovery that was ignored for many
after their development, initially leds were used
mainly for orientation lights. now they can be found
led worK without
relYiNg oN MercurY or
other toXic SuBStaNceS
years. in 1876, ferdinand Braun delivered a lecture
on the conductivity of crystals. he described his
experiments, in which he held a metal tip against
a sulphide crystal and discovered that in one direction
the crystal acted as a good conductor, but in the
other it conducted poorly. in addition, he noted, the
crystal’s conductivity increased steadily in the one
direction as the electrical current was increased. in
those days, science only knew about ohmic conductors
and insulators. the scientific community was bewildered,
because this effect was completely at odds
with the properties of materials that were known
at the time. this remarkable behaviour would not
in car headlights, torches, and signal and street
lighting. But it will undoubtedly be a while before
the light emitting diode finds its way into our living
rooms. Besides its high purchase price, many people
are discouraged from buying it due to the type of
light emitted. while there are now leds that produce
white light, many people find the light they produce
too “cold”. changing this situation is the primary task
of the light designers with several different lighting
manufacturers. until we reach that point, there are
still many other good arguments on behalf of the
led.
HYDRAULIKPRESSE 1|2011
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