Re: [NTLK] Backlight lifetime question

From: DJ Schönfeld (DJFair_at_web.de)
Date: Mon May 20 2002 - 04:59:46 EDT


Hi, Ifound this article from Pascal B. Kreil, Hagen/Germany
(www.pda-lifwstyle.de):

Huch - everything so darkly here!
One hears complain Newton user again and again, the background lighting
Newton became weaker. Then always in demand why this happens and like for a
long time lasts it, until the foil does not shine any longer.....

Why does it shine?
The used foils for the background lighting are based on the so-called Cold
Light emission technology, which was investigated berits in the sixties for
military purposes.
Note! Now it becomes technically! Particularly endowed Phoshor atoms in a
sinusoidal elekrischen field send photons with the zero crossover of the
sine wave, while in the rising flank of the sine wave electrons become
"heaved" into a neighbouring bowl. A EL(Elektro Luminiszenz) foil is
developed like a condenser, against which the electrical field must rest
sinusoidally. Tensions from 50 to 150 V are thereby the rule with
frequencies from 400 to 2000Hz.
The art to let a foil shine as for a long time as possible lies in the
driver components. Square wave signals function not and/or destroy the foil
in quite short time, while sine signals must be brought sophistiated on the
high tensions. Crucial it is also that it must concern an accurate
sinus-wave voltage. The efficiency of a EL foil lies e.g. far more highly
than the one light emitting diode. For non--technicians: The foils shine,
because due to an electro-chemical reaction "light" develops.

Slowly the sun goes down
Now these foils do not shine technically conditionally eternally - the
particles do not react any longer with one another. The foils become slowly
darker.
Now the foils stop however not like a lamp or an LED with an impact the
service, but become slowly ever darker. Here we would be then again with the
driver component: Ever after tension and frequency are as high can it be
that these foils become only after nearly 10000 hours visibly (!) darker.
With Newton we may proceed from 1000 hours....

With Newton the foils seem to become however many faster darker. Why?
So far I and frequency of the tax component knew tension (naja, there is not
a direct tax component... But ' ne rather thick coil on the plate... these
does not suggest in any case a sufficiently high tension) yet to check.
There are however far more trivial reasons for an attenuation of the
Leuchkraft!
The foils are extremely UV light sensitively! Normally therefore a UV filter
layer must be applied on the display which can be lit up. One can evaporate
or with a foil realize these. This was not only very badly realized
obviously with Newton or. It can be that Apple in favor of the better
contrast (by the filter the display can seem easily rosa/violett) and the
legibility did without a filter. Thus reacts the EL foil Newton particularly
sensitively to UV light....
Well, one could say, does not use I him stop not in the stout sun. But thus
it is not done. Causes are also in nearly each household!
Like that a main factor for the attenuation is halogen light (exact). As
well as everywhere halogenleuchten for the working place lighting are used,
nobody on the idea would come that it possibly whom damage would know.
For a long time no more lights may be sold without a set forward filter
disk, but do not concern it not an all cure here. The UV radiation is enough
to weaken still out around the foil.....
If one compares Newton with under halogen light was worked and one with
under e.g. a fluorescent lamp was worked, then the lighting of the "halogen
victim" is clearly darker. I could already reconstruct that to several
Newton.
If it is then a daily so far that one cannot use the background lighting any
longer, then one could exchange the foil theoretically. Enfour had to offer
' times an idea the foils for DO-it-Yourselfer. From this however so far
nothing became.
Sometimes it would be possible that one could open a source for such foils
in Germany, set the case it someone a defective 130er/2K would make
available around to it to test to what extent a foil exchange would be
possible.
Sooner or later, as many is the lights will surely go out. With somewhat in
former times, with other later. But, do they go out....

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