“Christmas night, another fight Tears we cried a flood Got all kinds of
poison in, of poison in my blood, I took my feet To Oxford Street Trying to
right a wrong Just walk away Those windows say But I can't believe she's gone
When you're still waiting for the snow to fall Doesn't really feel like
Christmas at all……” it is the lyric of Coldplay’s Christmas Lights. I like it
very much, every year’s Christmas day the streets are always decorated by those
beautiful Christmas Lights. However, do you know how do LEDs Christmas Lights
work?
An
incandescent lamp produces light when electricity flows and heats a filament in
a gas sealed lamp. Fluorescent lamps emit light when voltage is transmitted by
electrodes that allow electrons to excite phosphors as they pass from one end
of a tube vacuum to the other, but what about LEDS? If there is no gas,
filament, phosphor, vacuum or arc, how do they produce light? Diodes are
electrical components that conduct electricity where the passing of electrical
current makes the diode light up. LEDs produce light in a very unique way; they
produce light via a process called Electro-luminescence，Electroluminescence
is a rather complex process that starts by turning a semi conductor material
into a conducting material.
Everything in the universe is made up of atoms, and atoms have a
positively charged nucleus and negatively charged electrons. Some atoms have
more electrons and others have less. For
example, an LED semi-conductor atom is typically a silicon crystal that has 4
electrons and the entire atoms bond perfectly to their neighbors, leaving no
free electrons (negatively-charged particles) to conduct electrical
current. But, when you dope the silicon
material by introducing an impurity that changes the balance, either adding
free (extra) electrons or creating gaps (holes) where electrons can go, either
of these additions make a semi conductor material conductive.
It
is the way that LEDs decorate our Christmas day, when you are enjoy the
beautiful Christmas day, please do not forget this big contributor. I always
believe that LEDs will play a more and more important role in the future.
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