The TV Story Part 3

From projection televisions to LED screens, we explore the more recent advancements in television technology. What the heck is HDR, anyway?

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Episode Transcript

Speaker 1 (00:04):
Get in tech with technology with tech Stuff from how
stuff works dot com. Hey then, everyone, and welcome to
tech Stuff. I'm your host, Jonathan Strickland, senior writer for
how stuff Works dot com, and today we're going to
continue our series on the history of TV technology. Now.
In our last episode where we last left off, if

(00:26):
you prefer or last week on tech Stuff, we covered
the contentious birth of the electronic television, talked about how
a couple of different inventors and companies were laying claim
to being the inventor of TV. And we also talked
all the way up to the the invention of color

(00:46):
TV and how CBS had tried to define color television,
but our c A eventually was able to undermine that
and create their own version, their own standard for color
t V that ended up becoming the standard. I'm gonna
try and pack a lot in with this particular episode
to talk about the significant developments that happened once color

(01:08):
television started making an impact in the sixties and seventies,
although I'm gonna have to backtrack some to cover some
of these topics, because, as it turns out, history is
not a very simple timeline of dates. Right. If you
want to explain how something works, sometimes you have to
follow that trail down a few years before you backtrack

(01:30):
and go back to an earlier point to go to
the next logical section of your explanation. I wish time
didn't work that way, because it would make organizing podcasts
way easier. Now, for the most part, I've stayed away
from talking about actual programming on television. In other words,

(01:50):
I haven't really talked about the types of stuff you'd
watch on TV, just the technology of television itself. But
television has really transformed our world in many ways, and
it also cemented several notions when it comes to business practices,
things like sponsorships and advertising. TV was able to establish
some basic rules that ended up being applied to other industries,

(02:14):
including the online world. And we've seen a lot of
growing pains because of that, because we've seen how the
online world is very different from the broadcast TV world,
and yet for a long time it was being treated
as if it were the same thing from a marketing
and advertising point of view. Uh And to this day,
we're still struggling with that that decision. But let's get

(02:37):
back to the technology section. So while our c A
and CBS, we're duking out which company would define the
color TV standard. Other eggheads were working on different ways
to transform the TV viewing experience. So as early as
the nineteen thirties, A T and T began to experiment
with coaxial cables to carry television transmissions to homes that

(02:58):
couldn't receive over the air signals. And this was a
problem not just in remote areas that were really far
away from transmitters, but also in big cities where buildings
could block signals. So I've covered cable TV and other
episodes of tech stuff. I'm not really going to dive
into it here because it would just be repeating stuff

(03:19):
I've talked about in previous episodes. But I'll just say
that it was the rise of cable, particularly in the
nineteen eighties, that transformed television again and gave audiences far
more options than just a few local channels. It's also
what gave rise to superstations that could cover an entire region,
an entire country. The United States is big. For a

(03:41):
long time, everyone just had access to their local affiliate stations,
so they didn't have access to things that were playing
in other other regions, other markets. Here in Atlanta, you
could pick up Chicago stations occasionally and you can see
the Chicago version of the same stuff that you would
get with in Atlanta based version. But after the the

(04:03):
widespread use of cable, we started seeing these nationwide networks
that were the same across the entire United States. That
was only made possible through cable TV. But I again,
I covered that in a previous episode, so we're not
really going to focus on that today. Now, in the
late nineteen thirties, going back pretty far, Dr Fritz Fisher

(04:23):
of the Swiss Federal Institute of Technology dreamed up a
way to project television images on a much larger screen.
So instead of just having a little twelve inch screen
that you stare at, this would be a projector that
could take TV signals and projected across a much wider
viewing area. And in fact, the first working projection TV

(04:43):
got its start in Europe in the nineteen thirties. Now,
before I explain more, I should say that Dr Fisher
wasn't the only person working on this goal. Lots of
people were trying to create projection televisions, including ones who
had been working on something before Dr Fisher got started.
Some even had a few working models, but most of
them were producing very dim pictures, so you couldn't see

(05:05):
them easily projected on a screen. So while I say
Dr Fisher invented the projection television, that's really an oversimplification.
Lots of people invented similar devices, and that seems to
be the case with technology as a whole. Whenever we
say so and so invented something, there almost always needs
to be an asterisk after that statement so that you
can clarify other people were working on this too. It's

(05:27):
just one incarnation ended up being superior to the others. Now,
this particular invention's goal was to project an image large
enough for a theater sized viewing space, and several movie
studios were interested in this technology because it could provide
another source of revenue. If you didn't have a television,
you could just hop down to your local movie house

(05:48):
and check out television broadcasts there. But first someone had
to make a gadget that could project a televised broadcast
onto a screen. Now, Fritzie he unveiled a working prototype
back in n teen forty four, and he received the
US patent for his invention in ninet and he called
it the IDA four television system. Now IDA four is

(06:09):
spelled E I D O P h O R, and technically,
if you're being kind of generous, it means image bearer
roughly speaking. And here's how it worked. I'm gonna go
a little easy on this because the technical details get
pretty complicated, so we're gonna kind of take a bird's
eye view of this. First. Dr Fisher knew this system

(06:32):
would need to be very bright to illuminate a theater screen,
which was a problem. The other systems were running into
much much brighter than a normal television set. So for
that reason, he decided to use a powerful arc light
to provide the initial illumination, which was essentially a booster
for the image, to make sure you got that bright
enough so that when it projected on the screen it

(06:52):
was visible. Then he had to find a way to
modulate that light, in other words, to manipulate the light
to actually make the moving images you would see on
the screen. And his solution was to create an electron
gun system that we used a very thin layer of
oil the heat called IDA four liquid. So this is
not wildly different from cathode ray tube television screens. Remember

(07:16):
a cathode ray tube generated a stream of electrons, and
you would use that to paint the backside of a
television screen which had a phosphorus coating on it. So
as the electrons made contact with the phosphors, they would luminess,
they would light up. This is kind of a similar idea,
except that you didn't have that phosphorus layer on a screen. Instead,

(07:39):
the arc light would shine through a window and sometimes
also a color wheel, a mechanical color wheel to add
color to the image. That's the same style of color
wheel that CBS was pioneering in their color television UH
standard that they were pushing. Then that light, after it's
gone through the color wheel, would go through what is
called a condenser lenn. Now, when light passes through a

(08:02):
condenser lens, it aligns in parallel or collineated ways, so
or collimated I should say not collineated collimated ways. You
have these parallel rays of light after they pass through.
So this is useful if you've got say a source
of light that is diverging, it's spreading as it extends
outward from the source. If it goes through a condenser lens,

(08:24):
then it concentrates into more of a beam. So you
can think of those flashlights that have the really narrow
beam that come out the end. Chances are they're using
a condenser lens to create that beam. Uh. So it
keeps the beam nice and tight, and those parallel rays
of light would then encounter a mirrored bar system I mean,

(08:47):
I mean physical bars. Think of like iron bars on
a window, except instead of them being ironed, they're actually mirrors.
And it's angled in such a way that the light
coming from the arc lamp gets reflected uh ninety degrees
downward or to the lefter to the right, doesn't really matter,
but generally we diagram this as being downward. That light

(09:10):
would then hit a spherical mirror that would have a
very thin coating of this oil on it this ida
forore liquid on it, and pointed at this spherical mirror
was the electron gun. Now, the electron gun would fire
electrons just as a CRT tube would inside a television. Uh.

(09:31):
By the way, CRT tube, I'm being redundant. It's like
a t M machine or pin number. But a CRT
would fire electrons at the screen. In this case, the
electron gun is firing electrons at that oil. The electron
collisions would cause electrostatic charges to form on the surface
of the oil, which would then make the oil create

(09:52):
these wave like corrugations, and the high of the waves
was proportional to the strength of the video signal or
how bright it needed to be. This wave like action
on the oil is what actually modulated that light. So
you had the light coming in, reflecting down off those
mirrored bars, hitting this spherical mirror, and then being modulated
by this undulating oil. And by undulating, I'm talking about

(10:16):
atomic size changes in what was going on on the
surface layer of the this oil. That would then be
reflected back up through the bars of this mirrored bar
system up toward a projection lens, which was then directed
at another mirror that would reflect the projection onto the

(10:39):
theatrical screen. So some of the light goes through those bars,
continues upward and hits that projection lens. Now, but this
is where that ninety degree turn is really important, because
without that ninety degree turn, the arc light would just
be shining lights straight through a projection lens, and all
you would get is a blank screen, just just project

(11:02):
just light projected on a screen. No image would be there.
By having this mirror there that would let some light
go through. You could angle that light downward and have
the projection lens above the mirrored bars, so only the
reflected light is what ends up being put back onto

(11:24):
the screen. The light directly from the arc lamp would
not hit the screen, so you don't have to worry
about the image bleeding out or just being a blank screen.
It's actually a really interesting system, and again it gets
way more technical than what I'm describing right here, but
without the use of visuals it becomes increasingly difficult to

(11:44):
explain how this works, and light modulation, as it turns out,
gets into some pretty heavy physics. And we've got to
be completely honest here, I think I'd do a really
lousy job at describing the whole process without a lot
more work on my end to really get grips with
the science of it. So part of this is because
it's difficult to explain without visuals, but the other part

(12:07):
is just that when you get down to the physics
of light, I have a basic understanding and would need
to study a lot more to get a deeper understanding
in order to express exactly how this machine worked in
a more meaningful way. So please cut me some slack.
I'm not an optic scientist. The point is this contraption,
which weighed nearly two thousand pounds, allowed a projectionist to

(12:30):
send a televised signal to a large movie screen. And
the reason it weighed so much was because it required
a lot of power. So you had a lot of
power elements inside this thing. Uh. The electron gun and
the IDA four liquid also had to be kept inside
a vacuum, so you needed to have vacuum pumps to
make sure that you maintain that vacuum inside the chamber
with the IDA four liquid, otherwise you wouldn't get the

(12:53):
results that you needed. Also, temperature changes could affect the
performance of the oil itself, so you had try and
keep the temperature of the whole device fairly constant, which
meant that you had to include fans to blast out
extras extra excess heat. So there are a lot of
different components that went together to make up this thing,
which meant that it was enormous and heavy as a result. Uh.

(13:18):
By nineteen fifty two, television had found its way to
the Great White North a k a. Canada, and uh,
here's a shout out to all my viewers in Canada.
You guys are awesome. You guys might have been a
little late to the TV game, but you've also produced
some of the greatest writers and television performers in history

(13:38):
from SCTV, two Kids in the Hall and hundreds more.
But then you also gave a Seline Dion, So don't
get full of yourselves. You need to think about what
you did. In nineteen fifty six, we get another interesting invention,
one of my favorites, Zenith revealed the Zenith Space Command.

(13:59):
So Zenith Space Command, uh, in case you're curious, was
not a computer game. It was a remote control. It
was the remote control, the first wireless remote control that
was successful in the consumer market place. It was not
the very first wireless remote control, but was the first
one to really be viable enough to make it to market.

(14:22):
And it was invented by a guy named Robert Adler.
And I probably should do a full episode on Robert Adler.
He was born in Austria, but he left Austria during
the rise of the Nazi Party in the nineteen thirties
and he moved around Europe a bit, went to the UK,
and eventually immigrated to the United States. Then he took
a job at Zenith Electronics in the R and D division. UH. Now,

(14:45):
before Adler's invention, remote controls hadn't seen much success beyond
the laboratory. Early versions were actually tethered. In other words,
they had a cable that would connect back to the TV,
so really the remote control was was tied to the television.
You couldn't go anywhere with it. Uh It limited their usefulness,
so they never saw widespread adoption. And an earlier wireless

(15:09):
system used visible light and light sensing photo cells on
the television itself, so it's almost like a little flashlight
and if you pressed a button, it would flash a
certain sequence to send a command to the television, which
would then detect it through photo cells. But there's a
problem there. It was depending upon visible light, and it
turns out we use a lot of different sources of
visible light because we do not see so well in

(15:31):
the dark. So if your television set was exposed to
other sources of visible light, like the sun, it could
mistakenly interpret those light sources as being commands and the
next thing you know, you can't hear anything because the
sun keeps lowering the volume on your television set, so
that was a bit of a problem. Adler had a

(15:52):
different solution um, and it was different from the ones
that we have today. Today's remote controls mostly rely on
some other four of electromagnetic radiation, whether it's infrared or
some form of WiFi radio signal. That's what most modern
remote controls rely upon today. But back in the day,
it was all about ultrasonic frequencies. Old television remotes used

(16:18):
sound to control TVs, and inside these remotes were actual
small metal bars, typically made out of aluminum. So you
had physical little metal bars inside this remote control box,
and if you pressed the button, it would cause a
little lever to make those bars vibrate, and that vibration
would give off an ultrasonic frequency, and a receiver on

(16:39):
the television would quote unquote here this frequency and then
transfer that into some form of control. So it might
be volume up or volume down, it might turn the
TV off or on, it might change a channel. Uh,
you know, your basic remote control functions. And these sounds
are ultrasonic, so they're beyond the range of Hugh been hearing.

(17:00):
Remember human hearing goes from about twenty hurts to twenty
killer hurts. Uh. Typically that's that's average. Your results may
vary depending upon the human of choice. My hearing is
probably I'm at an age where it's probably not nearly
as high as twenty. Killer hurts for me because as
you get older, you start to lose the ability to

(17:21):
detect those higher frequencies. This is why you would hear
stories about certain convenience stores employing sound systems that could
play a pitch that was above what the typical adult
could hear, but within the hearing of say, gnarly teenagers
who are always clogging up the store. You just crank

(17:42):
up this irritating pitch that only the teenagers can hear,
and next thing you know, there aren't bothering you anymore.
It's a brilliant technology. In my mind, it saves me
from yelling at kids to get off my lawn. But
going back to the TV, this was supposed to be
at signals that not even teenagers can hear, even if

(18:05):
you ask them. Now, because the remote control and receiver
we're using these ultrasonic frequencies, you could cause your old
television to freak out with stuff like loose change or slinky. Really,
any metal or metallic device that could vibrate at a
at a frequency that would generate ultrasonic sound. You could

(18:28):
end up affecting a television this way. So this explains
how back when I would sit down to watch Saturday
morning cartoons, which, by the way, we're a thing that
used to happen. Now you don't really see them anymore,
but back in the day, that's when you would watch
cartoons Saturday mornings. You can get up seven or eight

(18:49):
am and just start watching on various television stations. Anyway,
when I would sit there and watch and then just
idly fidget with a slinky, I could magically make my
TV do stuff like turn the volume down over and
over again until I had to track down the actual
remote control and turn the volume back up because I
couldn't do I couldn't control the TV. I could make

(19:10):
it do things, but I couldn't make it do what
I wanted it to. It just would do whatever the
ultrasonic frequencies were telling the television to do, and I
couldn't have that kind of fine control over my slinky
manipulation skills to make it do what I wanted it
to do. But still kind of cool. Uh. The later

(19:30):
systems that used infrared and WiFi won't respond to ultrasonic frequencies.
But I maintained it's still fun to tell kids about
how a slinky used to be able to control a
television and then don't tell them that it doesn't work anymore,
because they could provide hours of entertainment for all involved. Anyway,
I just like tricking kids. I guess that seems like

(19:53):
a good segue. Let's take a quick break to thank
our sponsor, So let's skip ahead to nineteen sixty two.
That's when broadcasting companies from the United States, the United Kingdom,
and France collaborate on the design of the world's first

(20:16):
active communication satellite called tell Star one. Companies like Bell
Labs and A T and T took part in this,
as did NASA and the British Post Office and the
French Post as well. This satellite would allow a broadcast
station in Europe to send signals over to the United
States and vice versa. It also allowed for satellite uplink

(20:38):
on phone calls and faxes, so you could have transatlantic
communication via satellite. You didn't have to worry about laying
a cable down between Europe and the United States, for example,
so very useful now. The satellite entered low Earth orbit
on July tenth, two and it used for teen whole

(21:00):
lots of power. Chances are your laptop uses more than that,
but fourteen wats of power for this little satellite, and
it generated electricity using thousands of solar panels on its
outer hull. And it was spherically shaped, So if you
look at a picture of the tell Star one and
you don't have anything next to it to give you
any sense of scale, you might think it's the product

(21:23):
of a marriage between a disco ball and the Death Star,
which I maintain would be an awesome technology. But then again,
I also happened to own the Star Wars and Other
Galactic Funk vinyl album by Miko. Anyone out there who
knows what I'm saying man rock On as an awesome, awesome,

(21:43):
cheesy album, and I really do own it on vinyl.
The tell Star one satellite allowed for near instantaneous transmission
across the Atlantic with very little delay. It was possible
to watch real time live TV broadcast from across the
and but you could only do it for about twenty

(22:03):
minutes because the satellite was in low Earth orbit. That's
a problem because at low eth orbit it is actually
circling the Earth multiple times every day. It took about
two and a half hours for it to orbit the planet,
which meant that you had about twenty minutes of time
where the satellite was ideally positioned to transmit signals from

(22:26):
Europe to the United States or vice versa. Later on
we would launch communication satellites much much further out from
Earth had very high orbits into what is called geosynchronous orbits,
and a geosynchronous orbit allows the satellite to move in
a pattern over the same general area above the Earth,

(22:46):
so as the Earth turns, the satellites orbiting at the
same speed as the rotation of the Earth same relative speed,
not the exact same speed, because obviously you have to
move faster the further out you are, but it would
be able to maintain a general position above a certain
region of the Earth, and it tends to move in
a pattern, often a figure eight style pattern. There is

(23:07):
a subset of geosynchronous orbit called geo stationary orbit, in
which a satellite appears to be directly above a single
point on Earth along the equator. You have to be
along the equator in order for this to work. But
that is a subset of geosynchronous. So geosynchronous and geo
stationary are not exactly the same. Geo stationary as a

(23:29):
subset of geosynchronous orbits. Just something for you to think
of next time you're doing pub trivia and this kind
of stuff pops up. I don't know about your pub trivia,
but it pops up all the time for mine. By
nineteen sixty four, broadcast networks in the United States began
to transmit color television programming on a regular basis. You
remember we talked about color TV in the last episode.

(23:49):
It would still be a few years before color television
sales outpaced black and white TVs. Uh, really, you're talking
about nineteen seventy And by nineteen seventy two you finally
got to a point where color televisions made up about
fifty of all TVs in the United States. And in
nineteen sixty nine, the world watched as footage from the
moon landing reached TVs across the globe, and the astronauts

(24:13):
on that moon landing had a special camera, and the
camera had its own mechanical color wheel inside of it,
which was the same thing I talked about way back
in the first episode with mechanical televisions, I also mentioned
them in electronic TVs. The mechanical color wheel in the
camera cut down on the need for expensive and bulky components,
and it also meant the astronauts didn't have to send

(24:35):
as much data at a single time down to Earth
within a transmission, so it cut down on the bandwidth
necessary to send images back down to Earth. Synchronized color
wheels on the planet, we're able to reinsert color into
images before transmitting them to televisions, and I think it's
pretty cool. The technology that dates all the way back
to the mechanical TVs of the past found its way

(24:56):
to the Moon. It's pretty nifty. Also, in the nineteen sixties,
scientists developed three technologies that would eventually displace CRT televisions.
That would be light emitting diodes or l e d S,
liquid crystal displays or l c d S, and plasma
display panels or p DPS. L c D televisions wouldn't

(25:18):
take off for a few years, but they would come
first out of those three. It would take a couple
of decades for plasma to become a viable technology for
television's although they started being used for smaller displays earlier,
and LED televisions are even more relatively recent. Although the
development of the l E ED dates back to the

(25:39):
nineteen sixties, we didn't see LED televisions until fairly recent uh,
But a lot of people were experimenting with these all
the way through the nineteen seventies, trying to get the
next technology for CRT S or to replace c r
T S. I should say, now, let's start with nineteen
sixty four in the invention of the plasma display panel.
So yeah, plasma di lays date back to nineteen sixty four.

(26:03):
It was co invented by Donald Bitzer, H Gene Slotto,
and Robert Wilson. Now they were working on developing a
computer display, not really a television, but the basic principle
is the same. The display consists of two panes of
glass that are pretty close together, but there's enough space
in between them to insert and inert mixture of gases,

(26:26):
which are typically neon and xenon. Those gases can turn
into a plasma, which is an electrically conductive gas has
some free electrons which allow it to conduct electricity. This is,
by the way, the most plentiful type of matter in
the universe. It's the stuff that stars are made out of.
Although they are much hotter than a plasma TV, You're

(26:46):
not gonna melt your house down with a at least
a properly functioning plasma TV. The plasma, once it's carrying electricity,
then excites phosphors, very similar to the way a cr
T television would use electrons to excite phosphors. And when
you do that, you increase the energy levels in the

(27:08):
electrons in those phosphor out atoms, and then they immediately
come back down. And when they come back down their
energy levels they have to release that excess energy in
the form of light, So the phosphers end up glowing.
They give off light, So the plasma takes that place
of the electron beam. And the first plasma display panel
could only display a single color. Uh they made some

(27:28):
in orange, green, and yellow. Those were your basic colors
that you would get for your computer monitors back in
the day. Now, the plasma display didn't take off in
the market or replace the CRT right away, largely due
to economics. It had nothing to do with the science
or the technology itself. It had to do with how
expensive it was to produce versus c RT technology. Semiconductor

(27:52):
memory was plummeting in price. This was something Gordon More
predicted in his obser vation that has since been called
Moore's law. Moore's law is not really about advancing technology,
so that's twice as powerful each year, or each eighteen
months or twenty four months, or however you wanted to
find the time period. It's really about how much less

(28:14):
expensive it is to manufacture those components and make it
UH viable as a marketplace product. So every time that advances,
it gives companies the incentive to develop even more powerful semiconductors.
That also means the price starts to come down, and
that's what was happening at this time. So CRT technology

(28:35):
became super cheap. So there was really no incentive to
pursue plasma display technology at that time, not for televisions anyway.
So it was only that point where the PDPs performance
were so above and beyond what CRT s could do
that it started to counterbalance this this UH disparity in price,

(29:00):
and once that happened, then we started seeing plasma displays
adopted more widely. It also allowed for much slimmer form
factors than your CRT sets. I mean a CRT is
essentially a vacuum tube. It's a vacuum tube that generates
a stream of electrons, which means you need to have
space in your television set to hold an electron tube.

(29:21):
Plasma displays don't need that. They have these two panes
of glass and then this gas that's in between them,
and then you just have to electrically excite the gas
the proper way to make the phosphors glow, so they
could be much much thinner than CRT screens. But again,
that wasn't really a concern until much later than the
nineteen sixties, so it would be a long time before

(29:44):
we would see the rise of the flat screen television.
But PDPs had an advantage over the other early CRT
replacement technology of l c d s. That was the
other big one. Plasma displays are not constantly back lit,
but l c d s are. Will get more into
that in just a second. That means you could get
a much better contrast ratio between the brightest and darkest

(30:07):
colors on display, so you can get those what they
call true blacks on a on a plasma display. Because
there's no light coming from behind shining through a layer,
whereas l c D s did have that light constantly
there as long as the television set was on at
any rate. Also, plasma displays had better viewing angles than
earlier l c D displays dead and better response time

(30:29):
and better color representation than early l c D s,
So eventually l c D would eliminate those advantages. They
would catch up to plasma displays. But this is the
reason why home theater enthusiasts back in the day, and
by back in the day, I really mean the ninety
nineties would swear by plasma over l c D technology

(30:50):
because of this color representation, contrast ratio, better viewing angles,
all that kind of stuff. Eventually, LED tech would push
both of those aside. But more on that in a second.
So let's talk about l c D s. That stands
for liquid crystal displays, and liquid crystals are sort of
a weird molecule. They kind of act like a solid

(31:10):
and they kind of act like a liquid. So solids,
I'm sure you recall, you guys, remember your elementary science.
They have all their atoms locked together, either in a
crystalline structure or not. But they are locked so that
they can't move around right, they're stuck in place. Otherwise
they wouldn't be, you know, solid, But liquids have molecules

(31:36):
that hang together, so the molecules don't break apart, but
they can't move around more freely than in a solid,
and they can change their orientation with relation to each other, uh,
without any problems. So liquid crystals are sort of a
hybrid between these two, and the l c D s
and television are affected by electric current. In their natural state,

(31:56):
these crystals have a twisted formation because of the way
are attached at either end inside a television display. More
on that in a second. But when you apply a
current to them, they untwist, and it's through this twisting
and untwisting that you're able to manipulate light and have
it go through to a screen and create the moving
images you would see on an l c D television screen. Uh.

(32:20):
That's the simple explanation, but let's dive into it a
little bit further. So we're gonna explain this in one
of my favorite ways to describe technology as a sandwich,
because lunch was a long time ago, y'all, So our
bottom bun in this sandwich is a light source, uh,
such as a fluorescent tube. That's your typical light source
in your early L C D s now. On top

(32:40):
of that first layer, that bottom bun, we have a
tasty piece of polarizing film. So polarizing film can align light,
polarize it in a certain way. Next, on top of
that we put a glass filter which is aligned the
same way as the polar rising film. Then we put

(33:02):
a negative electrode on top of that glass filter. That's
the electrode that says mean things about other electrodes. Not sorry,
that's just in my notes. This is actually the electrode
that puts out electrons. It generates electrons, sends those through.
It's the where the electrons come from. Now, on top
of the negative filter are are liquid crystals that we

(33:23):
arrange in a layer on that. On the other side
of the liquid crystals comes a positive electrode. This is
where the electrons quote unquote want to go to. Remember,
electrons are negative themselves and like repels like, so they
want to get away from the negative side and go
toward the positive side. Uh. So, on top of the

(33:44):
positive electrode is another glass filter, and on top of
that is another sheet of polarizing film, and that is
in a orientation that is ninety degrees off from the
first polarizing filter. So in other words, it's that a
right angle to the first layer. Then you've got the
glass cover or screen, and that acts as the top bun.

(34:07):
So here's what's going on. Light comes from the fluorescent tube,
it hits that first filter I talked about, which then
polarizes the light that puts the light in a certain alignment.
Let's say that light, now realigned, goes through the series
of liquid crystals which are manipulated by electric fields to

(34:28):
twist or untwist in certain ways. That actually changes the
lights plane of vibration as it's guided through this this
layer of liquid crystals until it passes through and it
hits that second polarized filter. Now, any light that matches
the polarization of that second filter can pass through. Any

(34:52):
light that doesn't match that polarization is stopped. So you
can only pass through if you're aligned with that same polarization.
And think of it like a bunch of vertical slits
that are next to each other. And if you have
a ray of light that isn't vertically oriented, it cannot

(35:12):
fit through that vertical slit. Or if you prefer think
of round pegs and square holes, you can't get the
round peg through the square hole because the shape doesn't
fit correctly. It's the same general concept we're talking with polarization.
So some of the light is angled the proper way
and it passes through, and that's the light you see
on the screen. Other light gets blocked by this second

(35:33):
polarization filter and doesn't make it to the screen. Uh,
and that is your basic l c D television screen. Now,
in a color display, which is typically what we see
with l c D television's, each pixel has three cells.
These are sometimes called sub pixels, and these are red, green,
and blue, and the combination of these make up all

(35:55):
the possible colors. We talked a little bit about color
television in our last episode, so the same principle applies here,
except we're talking about light being passed through l c
D s as opposed to an electron gun painting phosphors.
Each subpixel can be independently controlled to make lots of
different colors when you combine these over the course of

(36:17):
multiple scans within a second, and some companies enhance this
with other additional subpixels, like sharp they have a yellow subpixel,
and they claim that this leads to more accurate color representation.
But this method also means that you always have a
light source behind all those liquid crystals and polarization filters,

(36:39):
and while it can prevent light from coming through, there's
still usually a distinct glow coming from the screen because
the forests and lights are just lit behind the whole time.
Does that means? Sel c D screens, particularly the older ones,
had trouble displaying darker colors without light bleeding through the screen.
So if you had a perfectly ark room and you

(37:01):
were watching a movie on an old l c D
television and the screen goes to black, you would actually
see almost like a charcoal gray screen. You would still
be able to pick the screen out from the rest
of the room because it's not able to present a
true black because you always have that backlight on. Uh.

(37:22):
But then again, you know, while while plasma screens could
present a true black, they also had another problem called burning,
which is when you have an image that's on display
for too long on a screen and it burns into
the screen itself. So, for example, if you had a
just a waiting screen showing like maybe it was a
paused movie or television show or something along those lines,

(37:46):
and it was on the plasma display for a really
long time. This happened a lot with demo displays that
would show a logo for a really long time that
would burn into the screen, so you could always see
a ghostly image of that on on older alasthma displays.
Just like l c D technology eventually evolved to the
point where the differences between l c D and plasma

(38:07):
became less noticeable. Plasma technology also advanced to a point
where burning became less of a problem, but those early
screens definitely suffered from that problem. Now LED televisions might
as well fell finish the trifecta here. LED televisions use
light emitting diodes as the light source instead of fluorescent tubes,

(38:30):
but they still use liquid crystals a layer of liquid
crystals to determine which light gets through to those polarization filters.
So really you could think of l e D television's
as a subset of l c D t vs. But
with l e D s there's much better power efficiency
uh than those fluorescent based sets because l E D
s are are just extremely efficient. Also, you could allow

(38:53):
televisions to become even more thin than before. L e
D s take up very little space, and because you're
using an array of l e d s instead of
a couple of fluorescent lights, you have way more control
over which l e d s are lit up at
which time, so you could produce better contrast ratio with
an LED television set than with a traditional l c
D set. And I've done a lot of episodes about

(39:15):
l e d s in the past, so I'm not
going to divide into it more here except to say
they're pretty boss. Then there's no lead sets, but I'm
not really going to go into that at all because
it would require a full episode on its own. But
those are organic light emitting diodes. That's what allows you
the truly super thin screens. And they can also be flexible.

(39:36):
You can get those curved screens, you can get screens
that can change shape. You might remember there were a
couple of television sets that were promoted as being able
to change from flat to curved. I think most companies
have abandoned that now because there just wasn't widespread adoption.
It was almost as a curiosity but oh lad technology

(39:58):
allows that to happen. Now, in the early nineties seventies,
now that we've described the technologies that would eventually supplant
CRT s, we started seeing the first of giant screen televisions,
and the earliest were CRT televisions that were projection TVs.
That meant that they used cathode ray tubes just like
traditional televisions did, or at least they also used CRT s.

(40:22):
It was actually a little different from the way traditional
TVs used them. It also made the sets really heavy
and they gave off a lot of heat. If you've
ever used an old front or rear projection television that
use CRT s, you know how big and clunky and
bulky and hot they got. They also worked a little
bit differently, as I said, from standard CRT s. But

(40:45):
the the early early models were front projection televisions. That
meant that you had a component that actually sat in
front of the TV and projected onto the screen, sort
of like a movie projector does to a movie screen, except,
of course, we're talking about television images here, not not
a light shining through moving film. Now, the projectors in

(41:07):
front of the television consisted of three light guns. So
each of these light guns had a CRT inside them.
There was one that was red, one that was blue,
and one that was green. Big surprise there right the
colors that we would use to create all the other
colors that could be represented on a television. So all
three of those colors would combine. The series of images

(41:30):
would combine in different intensities to create the moving images
you would see in front of you as you're watching
this television. Uh, and the intensity of the light through
each light gun is what would determine the final color
as it was painting this picture. So the projection screen
was was painted and pretty much the same way the
CRT TV sets painted the back of the screen with electrons.

(41:52):
These televisions were generally lower resolution than what you would
get with a typical CRT screen, So while you could
get a bigger television at it wasn't at the level
of quality that you would expect with an old CRT
TV set. And then there were rear projection CRT t
vs where you would have all those components, but they
would be inside the television itself and projecting on the

(42:15):
back of the TV TV screen, but still a projection
it wasn't painting phosphors the way a CRT TV set would.
These were huge. I should know. I had one once
upon a time. I bought one just as CRT rear
projection televisions were going off the market, so it was
super cheap. It's also huge, took up an enormous space

(42:37):
in my living room, and now it's in storage. True story,
all right, so let's skip ahead of it. Television continued
to proliferate around the world, with color television's eventually becoming
the standard and replacing black and white TVs. Meanwhile, over
in Japan, researchers were hard at work developing the next
generation of television technologies, and a team of scientists at

(43:00):
NHK we're able to demonstrate an h d TV format
with one thousand onive lines of resolution, so HDTV stands
for high definition TV, and those lines of resolution um
were more. It was a huge amount, Like five twenty
five was the standard here in the United States. It's
different than other parts of the world, but here in
the US you had five hundred twenty five full lines

(43:23):
of resolutions. So one thousand, one and twenty five was
a big jump up. And remember uh, more lines of
resolution means sharper pictures. This happened all the way back
in nineteen eight one, So the first h d TV
standard proposed came in eighty one, which blows my mind

(43:44):
because it wasn't until the mid nineties that I really
started seeing HDTV take off. Two years later three this
team from NHK actually demonstrated this technology at a conference
in Montrue, Switzerland. Uh and I hear they were rewarded
with many, many chocolates. It's good work for them. However,

(44:05):
in nineteen six they met with resistance from agencies in
Europe and the United States. The agency's declined to acquiesce
to Japan's request that this version of HDTV become the
global standard. So Japan went ahead and started broadcasting in
HDTV in Japan. Uh and they did that despite the

(44:27):
fact that everyone else said, no, that's not going to
be the standards. So they started doing that in nine
they actually became the first country to regularly broadcast in HDTV. However,
the rest of the world would resist adopting their standard
and instead try to develop their own, so you had
various components all doing this at the same time. The
United States had the FCC creating a special committee to

(44:50):
determine what the new digital standard in the United States
should be, just the digital standard, not even the HDTV standard.
Over in Europe you had companies introduced the D two
Multiplexed Analog Components standard to lay the groundwork for analog
HDTV over on the continent, in a multinational committee of

(45:12):
engineers decided that the Moving Pictures Experts Group Format IMPEG
two would be the global standard for broadcasting digital television pictures.
But they did not standardize a method of encoding the
sound or a method for actual broadcast of that standard.

(45:33):
So they said, this is going to be the standard
to carry the information, but they didn't standardize the way
to deliver it or how to encode sound with it,
which meant every country developed its own standard which are
incompatible with other countries, thus creating all these compatibility issues
between different regions. That was fun. Now I've got a

(45:54):
lot more to talk about in this third section about
the history of televisions, but wore I jump into that.
Let's take another quick break to thank our sponsor. Let's
pick up in that's when direct TV launched. I guess

(46:17):
literally anyway, I should do a full episode just about
satellite television, because I don't think I have. I've covered
cable television pretty extensively in past episodes, but I don't
think I've covered satellite TV that much. I might have
talked about a little bit back when Chris Palette was
my co host, because he used to work tangentially anyway

(46:38):
with a satellite television company, and he would always recuse
himself at the beginning of those discussions. So maybe I
will do a full episode about satellite television sometime in
the future. In the FCC would approve a new standard
called Advanced TV in the United States that included both
multi channel standard digital television also known as s DTV,

(47:02):
as well as high definition television. By more than twenty
stations in the US across the top ten markets in
the country began to broadcast in digital formats rather than
an analog. Now more current televisions are equipped for this,
but older sets would actually need a converter in order
to accept a digital signal and then converted into an

(47:24):
analog signal that the television could then display. By the
mid two thousand's, we reached the time in the US
when all broadcasts were to switch to digital only that
actually ended up getting delayed to the late two thousand's,
UM that first decade, in the late two thousand's, I
should say, because we're still pretty early on People from
the Future. This episode was recorded in seventeen, so I

(47:47):
don't mean like two thousand, nine hundred, So coolier jets. Also,
thanks for tuning in. But anyway, this, this conversion from
digital or from analog to digital, I should say, caused
some confusion in the marketplace, more than a little confusion,
partly because the messaging was muddled. It was hard to

(48:08):
understand what was actually being communicated. Consumers were not really
sure if their televisions would continue to work after the
switchover date, and I suspect a lot of people bought
unnecessary converters from analog or digital to analog, thinking, oh,
I guess I need this so that my TV can
display it, not knowing that their television was already accepting

(48:30):
digital signals because all the recent television sets that have
been sold over the past decade really were equipped for
digital broadcasts, not for analog, but not everyone knew that UM,
and so a lot of people ended up thinking they
needed a converter if they didn't really and they didn't
really need one. So the the problem was that anyone

(48:54):
who was using an analog television set would be left
behind because their television would no longer be able to
take over the air broadcast. And this only affected over
the air as well. If you were cable you were fine,
your cable box was doing everything for you. Um, but
if you were doing over the air, like you were
using an antenna to get your programming, then you needed

(49:15):
to have an adapter if you had an old analog
television set. But this, all of this information was communicated
really haphazard and ineffective way. Uh. The cynical among us
might say, well, that's the government for you, but really
it just was a It was a really chaotic and
confusing time for a lot of consumers. One of the

(49:38):
earliest episodes of tech Stuff I ever recorded was about
this switch. I recorded it with my original co host,
Chris Palette, and if you want to listen to that
now completely irrelevant episode, it is called do I really
need a digital converter box for my TV? I published
on July four, two thousand eight, Bastille Day. The answer,

(50:00):
by the way, to that question is no, you do
not need a digital converter for your TV, unless you've
been wondering since two thousand eight why you're perfectly serviceable
analog television is no longer picking up more than mindy reruns,
in which case the answer it might be, yeah, you
do need a digital converter for your TV, and you
have needed it for like a decade, But the better
answer is probably just buy a new television anyway. Since

(50:25):
that time, we've seen the emergence of ultra high definition television.
This includes four K and eight K televisions, which up
the anti on resolution and honestly, at least in my opinion,
this is my opinion, unless your television is truly gargangeline,
you really don't need to worry about four K and
eight K television too much. If you sit close to

(50:47):
a really big TV, you'll notice the difference. But if
you're at the proper distance, which most of us are
sitting too close to our television's already. But if you're
at what is considered the proper viewing distance and your
television isn't at seventy inches or larger, I doubt you'll
really be able to see a huge distinction between HD
at ultra HD. Now some of you might, but my

(51:10):
old eyes have trouble telling the difference. If you put
an ultra HD set and an HD set of comparable
size at the proper viewing distance away from me, I
bet you it would be really hard for me to
tell the difference, assuming that they both were calibrated to
perform at peak performance. Because there are ways of making

(51:30):
TVs look better or worse, people in electronics stores know
this trick. You can. You can calibrate one television to
look really good on the display floor and another one
to look less good because the really good one costs more,
and you can push people to buy the more expensive
television set. But if you truly calibrate both of them properly,

(51:55):
you might see less of a difference. That's not to
say that all TVs are created equal. They aren't, but
sometimes these differences are exaggerated in order to make a sale. Also,
you've got to remember that anything that was calibrated for
the show floor is probably lousy in your living room.
You're gonna have to have it recalibrated so that you
get the effect you what in your home theater based

(52:18):
upon the light levels and other elements in your home.
But that's a whole episode all by itself. Anyways, you
might suspect these ultra high definition televisions cram way more
pixels onto the screen than either HD or certainly more
than standard definition television sets. And that's what resolution is really,

(52:39):
It's the number of pixels that you can fit within
the frame of a picture. More pixels generally means you
can represent finer details and make it less blocky. So
you might remember in a previous episode in the series,
I gave an analogy in which I talked about trying
to make a picture of the Eiffel Tower using solid
colored bricks. So the small are and more numerous the

(53:01):
blocks I'm given, the more accurately I can represent that image.
And that's the case with televisions. As pixels get smaller
and more numerous, the images they produce can have details
so fine that the human I really can't detect it
unless you're right up on that son of a gun,
and I mean inches away. Heck, when I first saw

(53:22):
eight K television sets at c e S, the representatives
there would actually hand out magnifying glasses so that you
could get just inches away from the screen, hold up
the magnifying glass and see the pixels, and that was
the only way you could even pick them out. And
at that point you might think, well, we've kind of
reached a level where it's indiscernible from the human eye

(53:44):
to tell the difference between this layer of resolution and
this layer of resolution again without the added benefits of
ideal calibration. Now, the NHK guys over in Japan, the
ones who were working on that HDTV standard back in
Night one were the ones who helped define the four
K and eight K standards. Now they managed to win out.

(54:08):
In this case, HDTV got kind of tossed the side,
but four K and eight K one the day. But
right now there's a scarcity of content at those resolutions.
We're starting to see that change over time. You're starting
to see some set top boxes that can generate and
ultra high definition stream of data. There's some online sources

(54:28):
that are offering this ultra high definition level of resolution.
Things like YouTube and Netflix are offering that as well
as other streaming services. You're starting to see some of
the other companies kind of dip their toe in this,
but it's still very early days for ultra high definition.
So you could buy one of these sets and not

(54:50):
really see the benefit from it unless you also subscribe
to one of these services where you're getting the actual
four K or eight K content. Otherwise you're just watching
high definition or even standard definition content on an ultra
high definition screen. Uh. And that's you know, that's that's

(55:11):
not great. It's not like it's magically a whole lot
better than watching it on a native standard definition or
high definition screen. Japan is actually trying over the air
broadcasts in uh D. I will likely see other countries
follow suit. Ah. Now, one last thing I want to
cover before I wrap up is something called high dynamic

(55:33):
range or HDR. And this is something that started popping
up at consumer electronics shows over the last few years
me five or six years. Really, Uh, this technology isn't
so much about the resolution of images, which is what
four K and a K are all about. It's more
about accurately representing the levels of light and color on

(55:54):
television screens. So, in other words, a TV with HDR
should start producing images that look so lifelike that seems
as if you're looking through a window rather than looking
at a television screen. Now there's a bit of confusion
about the types of HDR, because there's photo HDR, which
at a very high level essentially is talking about taking

(56:16):
a series of images at a different level of exposure
and then kind of using an algorithm to combine those
into an ideal image to present a photograph that's supposed
to be better than any of the components that went
together to create that photograph. Some people hate that effect.
That's not the same thing as television HDR. That's just
for photographs. T V HDR uses a slightly different approach.

(56:39):
The secrets TV HDR all has to do with how
much light is being shown on the screen, or at
least that's mostly what it has to do with as
far as television technology goes. A TV with hd R
should be able to produce more light in one part
of an image than in other parts, even pixel by pixel,
so it can create very subtle gradations of light and shade,

(57:02):
which is what makes images appear more lifelike and can
also aid in color representation. Although there are related technologies
to HDR that help with that, and this is what
makes his lifelike images, and we see the same representations
of light that we would see out in the real world,
so it's not just it's not just a replication, but

(57:24):
a true representation of what was captured on the production side. However,
it does not happen all on its own. To display
an image so that it looks real enough to reach
out and touch, you have to actually produce it in HDR. So,
in other words, using a regular camera to capture images
and send it to an HDR television, is it magically

(57:46):
going to create those incredibly vibrant, subtle gradations, right? You
have to have the HDR technology built into the post
production process to create the colors in the first place
for HDR to rep locate, So there's an extra step,
in other words, in the production process. So you probably

(58:08):
know that if you watch a standard definition program on
an HD TV, you're not magically watching high definition. You're
watching standard definition that's typically upscaled two approximate high definition television.
Upscaling essentially means that you are adding in extra pixels,

(58:30):
like neighboring pixels. Think of think of standard definition and
has a certain number of pixels, and let's argue for
the you know, just for the sake of simplicity, that
HD is twice as many pixels. So every odd pixel
in HD would correspond to a single pixel and an
s D, So you have pixels one and three an

(58:52):
HD which would represent pixels one and two in standard definition.
So what does the HD pixel to show? Well, upscaling
algorithms take a guess. They say, well, based upon what
these two colors are, we would think that the pixel
in between should be this color. So it it generates
a pixel that was not created in the initial process

(59:15):
of capturing that standard definition content. It's inventing information based
on a best guess, and the algorithms are completely what
generate those guesses, and they're generally pretty good. But upscaled
standard definition doesn't look as good as true high definition.
Same thing with high dynamic range. You need to have

(59:37):
that HDR source to enjoy the benefit of an HDR
television set. Without that source, it's just a technology that
really can't kick into gear. So you have to depend
upon the creators to generate the content, whether it's with
a Blu ray or whether it's through broadcast technology. Uh.

(01:00:00):
Otherwise you just have this cool tech that you really
can't do anything with. Probably an easier analogy to imagine
is three D Television's if you're watching something that wasn't
shot in three D. It doesn't matter if you have
a three D television unless it's doing that really awful
simulated three D, which I do not recommend. But if

(01:00:22):
it's taking just a regular image, then three D T
three D is just a feature that isn't used on
that content stream. So it does require that post production work.
But assuming that you get that, then you get this
incredible picture quality. And I've seen sets that have really

(01:00:43):
good hd R on them and it is gorgeous, Like
the color representation is breathtaking. It to me, it is
more effective than these dramatic improvements and resolution because, like
I said, once you get to a certain level, unless
you have a ludicrously enormous TV, and I'm talking like
a hundred inch television or bigger, then you don't really

(01:01:04):
notice the difference in the jump in resolution. Just because
our our eyes aren't that advanced. We can't tell the
difference unless we're really close to the screen, in which
case you can't really see everything anyway, because your fill
of view is completely covered by part of the screen
you're looking at. Uh HDR to me makes more of
a difference. One person has said, it's not about more pixels.

(01:01:28):
It's about better pixels, which is a rough way of
of equating HDR versus high ultra high resolution. I'm being said,
I'm sure that a lot of people can tell the
difference between high definition and ultra high definition. I'm not
really one of those people. I can tell a little
bit of a difference, but not enough. It's not as
dramatic as the change from standard definition to high definition.

(01:01:52):
Not for me anyway. Frame rates are another thing. I
could talk about frame rates and how television manufacturers have
created super fast refresh rates for their TVs, where the
screen is refreshing many more times per second than your
standard definition television's were. This works great for stuff that's

(01:02:13):
moving really fast on your screen, typically stuff like sports.
If you're watching sports on television and you have a
really fast frame rate, it may it reduces blur, so
you can see all the action very clearly, and it's
really impressive. If you're watching anything else, it's really disorienting.
That's where you start getting that that what people call

(01:02:33):
the soap opera effect, where everything starts looking like it
was shot on a soap opera set. Um. Yeah, Dylan's
giving the old thumbs down. Uh, This is where I
could go into a full rant about the Hobbit films,
and I have done it on other podcasts. Anyone who's
listened to those other podcasts knows what I'm talking about.

(01:02:54):
Don't get me started. I don't like high frame rates
or high refresh rates for that matter, for content that's
not sports related anyway, and I'm not a big sports fan.
I appreciate it, I just don't watch a lot of
it anyway. If I wanted to dive into ultra high
definition frame rates or refresh rates or HDR to any

(01:03:19):
real extent, it would require a full episode dedicated to
just that topic. And I really don't want to extend
this series further at this time, so I'll probably revisit
these topics further down the road. Let's get like a
couple of dozen episodes of other stuff before I tackled
TVs again. But I did have fun tracing the history

(01:03:40):
of the evolution of televisions, particularly the early days, because
it was such a dramatic story. Uh, for now, I'm
gonna wrap up this series, and even now I had
to gloss over a ton of stuff. I apologize for that,
but honestly, I don't want to sit here and record
for four hours, and Dylan definitely he doesn't want that,

(01:04:01):
so we're gonna leave it for now. If you guys
have suggestions for future episodes of tech Stuff, please let
me know. You can get in touch with me by
sending an email to the address text stuff at how
stuff works dot com, or you can drop me a
line on Facebook or Twitter. The handle at both of
those locations is tech Stuff H s W and I'll

(01:04:22):
talk to you again really soon. For more on this
and thousands of other topics, is it how stuff works
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