In 1960, the fledgling Sony company in Japan
decided to get into the television business. Their first foray into television was a remarkable
achievement in and of itself, being the first completely transistorized television. The TV8-301 wasn’t really a commercial hit,
but it was a technical feat. And just a year later, Sony’s dealers were
putting pressure on them to develop a color TV Sony was understandably reluctant as color
TV sales at the time were abysmal in Japan, but the sales department managed to exert
sufficient pressure on the engineering department to actually start work. Sony’s visit to the 1961 IEEE trade show
resulted in a glimpse of the Autometric company’s Chromatron tube. This picture tube worked in a completely different
fashion than the shadow mask picture tubes of the time. Rather than use three electron guns and a
matrix of holes to create the separation like the standard shadow mask picture tube did,
the Chromatron used a single electron gun combined with a vertical grille of electrically
charged wires at the front of the tube. In essence, the Chromatron relied heavily
on electronics to focus the electron beam onto the correct color. The beam was normally focused onto the vertical
green phosphor stripes present at the front of the screen. But the deflecting wires, placed about a half
inch behind the phosphors, could push the beam to either side, and light up the adjacent
phosphor stripe. The pattern of these phosphor stripes on a
Chromatron tube, sometimes called a Lawrence tube, were arranged as RGB - BGR. This was necessary due to the way the deflecting
wires worked. Without a charge, the beam wouldn’t be a
tightly focused and would light all three phosphors together. But by placing a charge between pairs of wires,
you would get both a tighter beam and the ability to push it left and right to control
the alternate colors. Placing a single green stripe between two
reds and two blues made this easier to accomplish, as the direction the beam was pulled would
reverse as it crossed each pair of deflection wires, as their individual voltage potential
remained constant. Using an RGB-RGB pattern would require constantly
reversing the wire grid’s charge, which would be a nightmare with the electronics
of the time. Already there was a lot of added complexity,
as with a single electron beam, it needed to be precisely modulated when producing a
color image to ensure it fired with the correct intensity as it repeatedly changed what color
component it was illuminating. The huge advantage of this chromatron tube
was a much brighter picture than conventional tubes using a shadow mask. Even though it used just one electron gun,
none of the beam’s energy was lost with this system, as all of it passed through the
focusing wires. The Chromatron also benefited from minimal
required convergence tweaking. This made the Chromatron tube much easier
to configure in the factory, and less likely to experience convergence problems requiring
adjustment over time. Remember, this was only seven years after
the first color television was mass produced, so we’re dealing with brand new technologies
with patents and licensing to go along with them. Sony saw both the better picture results of
this tube and the possibility to skirt around licensing costs and leapt at the chance to
take over the project. Sony bought the entire Autometric operation
from Paramount Pictures, who was behind it. But they’d soon discover that while the
Chromatron tube was a fabulous device once built, it was a veritable pain in the ass
to produce. It took until 1964 for the first Chromatron
television to actually be mass produced. And Sony sold each one at a loss. They were put on the market for a reasonable
198,000 Yen, but cost 400,000 Yen to build. That’s obviously not sustainable, but Sony
had faith that if they just stuck with it, they could get the manufacturing costs down
by perfecting the process as the production line matured. Well, they couldn’t. It continued to be a nightmare. So in 1966 Masaru Ibuka, Sony’s president
and co-founder, led the way to find a replacement for the Chromatron. Part of the reason was that General Electric’s
Porta-Color TVs had introduced an improved shadow mask design and new arrangement of
electron guns. These picture tubes moved the electron guns
from a triangle arrangement to an in-line arrangement, and shifted from the dot-pattern
of the original CRT designs to the vertical triad design you see here. The result was a much brighter picture that
was close to what the Chromatron was producing, and also eliminated many of the convergence problems conventional shadow mask tubes suffered from. So now Sony was stuck with a money-losing
product that wasn’t that much better than the competition. The engineers at Sony would alter some of
the ideas from the Portacolor and merge them with the Chromatron’s design. Susumu Yoshida asked engineer Senri Miyaoka
if the three in-line electron guns could be replaced by a single electron gun with three
individual cathodes, as this could decrease the cost of manufacturing. Turns out, yes you could! This initially made for focusing challenges,
but they were eventually solved. The other big development in this new tube
was similar to the Chromatron’s wire grille. The Chromatron’s electrically charged wires
were altered into what’s called an aperture grille, which was fundamentally similar but
didn’t require an electrical charge. The aperture grill was more of a single metal
sheet with slits cut vertically through it, though it is sometimes still referred to as
being made of wires. The grille separated the color components
by blocking their path much like the shadow mask, but kept the vertical phosphor orientation
of the chromatron. The aperture grill was very simple and very
effective, but perhaps most importantly to Sony’s pocketbook, was unique enough for
it to be patented! This new picture tube was called the Trinitron,
and it was better than what any of the competition were producing by a wide margin. Introduced in 1968, these televisions were
more expensive than the competition, but were universally well received. In fact, Sony received an Emmy award in 1973
for the invention of the Trinitron. But what made the tube so great? Let’s compare a Trinitron tube to a standard
shadow mask tube. So, when you put a Trinitron display side-by-side
with a conventional shadow-mask display, the most obvious difference is the shape. A Trinitron tube has a distinctive appearance
due to the geometry of aperture grille vs. the shadow mask. A shadow mask tube has a near constant curvature
across the face because the angles the three electron beams approach at to create the individual
Red, Green, and Blue color components need to be consistent across the whole face. The center of the tube is aligned with the
electron guns in the back, but the edges need to curve outwards to keep the inside face
more or less perpendicular to the source of the beam. A Trinitron tube, meanwhile, only curves side
to side. It doesn’t curve vertically, producing a
distinctive, cylindrical shape. This is actually a requirement of the aperture
grille. The aperture grille is fundamentally simpler
than the shadow mask, as it only needs to block the electron beams in the X dimension. Three separate beams arranged in a line can
be separated with just a slit. With the green beam in the center, it can
pass straight through. But the red and blue beams can only pass through
the left, and right, respectively. But this arrangement requires the slits in
the grill to always be perpendicular with respect to the three beams’ linear arrangement,
in other words the grille had to always stay completely vertical, as any tilt to the left
or right could cause cross-over and you’d get messed up colors. We all know from Ghostbusters that you shouldn’t
cross the beams! So, Trinitron tubes were designed to only
curve in the X dimension, keeping the face of the tube perpendicular to the electron
gun along its width, and the beam separation angle constant along its height. The other thing you’ll notice when comparing
a Trinitron TV to a conventional one is a generally much brighter image. This was the signature “big deal” of the
Trinitron. A shadow mask separates the color components
through individual holes in a metal sheet. The earliest CRTs using a shadow mask would
lose upwards of 80% of the beam’s energy to the mask itself, with only a paltry percentage
actually making it through to excite the phosphors and make the screen glow. This was improved over time through the use
of the in-line guns and the triad phosphor arrangement introduced with the Portacolor,
but the beam was still blasting its way through tiny slits. This required very powerful electron guns,
yet still resulted in a dim picture compared to conventional black and white TVs. The aperture grille, meanwhile, only needs
to blocks the beam from left to right to separate the color components. Vertically there is no separation at all,
and this allows much more beam energy to pass through it and reach the phosphors. This alone made the phosphors glow more intensely,
but the tubes were further helped along by uninterrupted phosphor stripes rather than
individual groupings. If you look closely at a Trinitron picture
tube, you’ll see continuous lines going from top to bottom with no horizontal separation
at all. When operating you see the stripes broken
up, but that’s merely the result of the way the image is made via scanning in horizontal
lines. As I’ve said now on two separate occasions,
phosphor groups you see in a conventional tube ARE NOT pixels. This is analog video we’re talking and any
Trinitron display helps to show how this is true by only containing stripes of phosphors. Now do you understand??? Anyway, a conventional tube’s phosphor groupings
have black lines above and below each grouping. These lines further reduce the image brightness
because, well, they don’t glow. I mean, that’s fairly obvious now isn’t
it? But they also cause other problems. Conventional color picture tubes would display
false patterns, sometimes injecting color where it shouldn’t be, when displaying an
image with fine patterns. This happens when the displayed pattern is
misaligned with the phosphor grid. Because a Trinitron doesn’t have a phosphor
grid, is was less prone to this occurring, so in many instances a non-trinitron display
would produce a Moire pattern or false color, and a Trinitron wouldn’t. Perhaps the only downside to the Trinitron
tube is a fine stabilization wire needed to prevent the aperture grille from vibrating. If the tube was exposed to loud sounds, the
aperture grille could vibrate and produce wild distortions in color. The stabilization wire would hold them together
and prevent this, but the wire itself is visible. On smaller tubes like this only one wire is
present, about a third of the way up from the bottom, while larger tubes would have
a second wire the same distance from the top. To be fair, these wires are barely visible,
since they are much finer than any of the scan lines, but they can be an annoyance when
the tube is displaying uniformly bright images. In most cases the image displayed would contain
enough variation to make the line essentially invisible. Now, the fact that this stabilization wire
was necessary may explain the Chromatron’s ultimate demise. The charged wires probably suffered from the
same vibration issues, particularly since they were so far behind the phosphors. And they couldn’t be stabilized as easily
as the Trinitron’s aperture grill because a wire holding them all together would remove
the required voltage differential between pairs. I’m willing to bet that the Chromatron would
have experienced continually worse problems as larger picture tubes were manufactured,
and it would have needed even more R&D to address it. The many advantages of the Trinitron picture
tube made Sony the undisputed king of televisions (at least from a quality standpoint) for many
years, and they were able to charge a premium for their televisions which many people were
willing to fork over. These two TVs show how successfully Sony was
with the product. These are obviously made many years apart,
but the actual picture tube is virtually the same. It might even have the same part number. Sony was able to keep pumping out the same
picture tubes, update the cabinets that held them and the electronics that drove them,
and they’d still be better than what the competition offered. From 1968 until 1998, any other manufacturer
who wanted Trinitron technology in their televisions would need to license it from Sony, and Sony
was plenty happy with just making the TVs themselves and made it difficult to do so,
though Apple was notably keen on using Trinitron tubes in their early color monitors. However, in 1998 the patent for Trinitron
expired, allowing the competition to make their own Trinitron-like picture tubes without
paying royalties to Sony. But, the name Trinitron was still a trademark
of Sony’s, so they had to fudge the name. Most of these new picture tubes would have
some sort of Tron in their title, like Mitsubishi’s Diamondtron. Sony’s timing was pretty good. By the time their patent had expired, LCD
and Plasma TVs were beginning to take over. By the mid 2000’s, CRT displays represented
a tiny fraction of televisions sold in mainstream markets. But for the entire 30 years that Sony held
the patent, it was virtually second to none. Trinitron remained important for many years,
and in some applications is still the preferred display device. I’ll tell you that for watching standard
definition content, nothing beats it, and that’s why this TV stays here along with
my menagerie of obsolete A/V equipment. Thanks for watching, I hope you enjoyed it. If you’re new to this channel, why not hit
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