Today, we look at LCD screens
It essentially all starts with back-lighting,
with here 8 Cold-Cathode Fluorescent Lamps.
This is the reason why LCD screens tend to
be chunkier than LED screen, as you need some
space to fit in some actual lamps, as opposed
to LEDs for LED screens.
On top of it comes a series of optic sheets
that will optimize the light to create an
evenly distributed and shaped light source:
We have a Light guide Plate that distributes
the light across the panel.
We have a diffuser sheet to further disperse
and smoothen the light.
We have a prism sheet so that the light exits
at its brightest angle to the viewer
And sometimes another diffuser
So, so far, we have just a light box (and
a good one if you want my opinion), but the
next layer is really where the magic happens,
with some pretty clever stuff: now comes the
Liquid Crystal panel!
While pretty thin, it is actually made of
several layers, and I will try to show you
a few of them.
At the back, glued on the glass substrate
we have a first polarizer that converts the
mixed polarization light into a polarized
light.
On the other side, we also have another polarizer
layer.
That one has been put at 90 degrees from the
previous one, meaning that no light is able
to go through, and per default, the screen
appears all black.
So how can the screen still produce an image
if no light can pass through 2 crossed polarizers?
This is where the Liquid Crystals come into
play.
Inside the Liquid Crystal panel is a glass
substrate that uses Thin Film transistor to
interact with the Liquid Crystals.
Submitted to an electric field, the Liquid
Crystals can pass or block light by changing
its orientation.
Coupled with a RGB filter, they are carefully
orchestrated by the TV electronics to enable
to right amount of light in the right direction
at the right place at the right time, so that
light can flow through the facing polarizer
and create a perfect picture on the screen.
Add now a few finishing layers to make it
pretty, and you pretty much have it, an LCD
screen and its nifty little technology!
