My TV needs an upgrade…
Really?! Coming from the
guy whose still owns [only] a flip phone, types on an 8-year-old IBM ThinkPad,
and plays his video games and music on an old Dell Dimension desktop? Yep, sure
is.
(CRT TV - Via 1800recycling.com)
Though I'm sure many of
you from the CR4 community could outdo me on old-tech retainage, it is still a
stretch for me to spend my hard earned $ for an HDTV, when a perfectly good CRT
television is still chugging away in my living room. But what can I say? I love the beauty of a high-def picture. And I love my movies.
But starting my quest to
find the right TV for the right price was much more involved than I thought it
would be. To start, I thought it best to familiarize myself better with the
science behind the two prominent TV technologies on the market today: LED-LCD and
Plasma. Here's a rundown of what I picked up:
TV Display: The Basics
To begin, it behooves me
to say that all TVs at their simplest level work in the same way -they take an
electric current and use it to produce or manipulate light at the pixel (or
sub-pixel) level. A pixel is the smallest item of information in a digital
image inside a computer or TV panel-i.e.,it is one of the thousands of little
dots on your computer monitor or TV screen. Each pixel is made up of three
"sub-pixels" - one red, one green, one blue. These colors mix in different
amounts to create the desired color, and thousands of pixels with different
colors combine on the display to create an image.
The difference between
different TV technologies lies in the process used to create the lighting in
each pixel.
LED
LCD TVs
Liquid Crystal Display (LCD) TVs use liquid crystals-molecules
that can be manipulated by an electric current. The LCD screens consist of two
polarizing filters (one horizontal and one vertical), with a layer of liquid
crystals contained between two glass
plates. When an electric current is applied, the liquid crystal aligns in a way
that either allows light through or blocks it out. The light then travels
through a color filter (red, green, or blue) and each grouping of the three
colors makes up one pixel. A thin film transistor layer is present underneath
the liquid crystal matrix which acts as a mechanism to rapidly switch pixels on
and off.

Layers of an LCD panel Viadigitaltrends.com
LCDs are referred to as transmissive displays because light
is actually transmitted through the display rather than inside the panel.There
are two lighting sources used in LCD displays: traditional fluorescent (known
as cold-cathode fluorescent lamps or CCFLs) and light emitting diodes (LEDs).
The sales name "LED TV" is really just an LCD TV which uses LEDs as the light
source.
Among LED LCDs, there are two "styles" used to position
the LEDs-edge lighting and direct lit. With edge lighting, LEDs are mounted
on the edge and light is channeled behind the glass using guides to provide
even distribution. This style allows for thinner profile TVs to be constructed.
Direct-lit LED TVs position LEDs directly behind the glass, with each LED
lighting up a set number of pixels grouped on the screen. This style allows for
what is called local dimming, turning off individual LEDs to create greater
contrast and better picture quality.
(Flat-screen TV - Via slashgear.com)
Plasma
(Emissive Display)
Plasma technology works very differently than LCD. The
display consists of two glass panels with a thin layer of pixels in-between.
Each pixel has three gas-filled cells (sub-pixels-one for each color) coated
with a phosphor(a substance that can exhibit fluorescence). When electric
current is applied to individual cells, the gas (a noble gas mixture, usually
xenon and neon) in the cells ionizes. Ionized gas (called plasma) emits
high-frequency ultra-violet (UV) rays which cause the cell's phosphors to
fluoresce, making them glow the intended color. Depending on which particular phosphor
the cell is coated with, it will create a red, green, or blue glow. The ionized
gas in a plasma TV involves the same mechanism as the fluorescent tubes and
bulbs we see everyday, but on a much smaller scale.

Anatomy of the plasma cell.Via
crutchfield.com
Plasma technology is referred to as an emissive display, because the
light generated comes from inside the panel (inside the individual cells) as
opposed to behind it.
Plasma vs. LED
Understanding how the technology works is one thing, but as a consumer
the bigger question for me is: Which one is better? Unfortunately, in the TV
world I found this to be a loaded question, since so much depends on one's
definition of "better"and what that particular person is looking for. But
figuring all that out for myself is a task for another day.
To be continued…
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