Plasma display panels: The colorful history of an Illinois technology
Emmy award marks plasma's "arrival"
By Jamie Hutchinson
"For most of its time, it was a solution looking for a problem,"
said Larry Weber (BSEE '69, MSEE '71, PhD '75) of the technology he
has dedicated his professional life to. Today that "solution"-the
amazing plasma display panel, invented at the University of Illinois
in 1964-seems to have finally found the problem (not to mention the
goldmine) it always deserved: carrying high-definition television (HDTV)
into millions of homes.
Weber's 60-inch plasma display, a prototype he developed for Matsushita
(bearing the Panasonic label), combines the large size and superb resolution
necessary for HDTV with the convenience of thinness. You can even hang
it on your wall. In fact, one of these marvels hangs on the wall of
Weber's upstate New York company, Plasmaco, an R & D arm of Matsushita.
When you see it, you'll know why the Society for Information Display
gave Weber its highest award in 2000 for his contributions to plasma
And you'll begin to understand why the TV industry gave a 2002 Emmy
award for technological achievement to the original U of I inventors
of the plasma display, Weber's old teachers Donald Bitzer (BSEE '55,
MSEE '56, PhD '60) and the late Gene Slottow (PhD '64), and their first
graduate student, Robert Willson (PhD '66), whose name appears alongside
those of Bitzer and Slottow on the original plasma display patent. Fujitsu,
the leading manufacturer of plasma displays, also shared the award.
Weber, Fujitsu, and others are now clearing the final hurdle that separates
plasma displays from long-term commercial viability: cost. With low-end
models selling for about $3,000-half the price of two years ago-manufacturers
seem well on their way toward making plasma displays the ultimate solution
to the problem of HDTV.
And yet, Bitzer and Slottow had a completely different problem in mind
when they created the early displays at Illinois. For them, the plasma
display was part of the solution to the problem of computer-based education.
What's more, U.S. TV companies who early considered plasma as an alternative
to the cathode ray tube soon dropped the idea. A few computer companies
stuck with plasma until another flat-panel technology, liquid crystal,
seized that market.
Other than that, only military contracts sustained a small plasma display industry in the United States, and so most U of I students who worked on the technology (including Willson) eventually had to find jobs in other areas. Meanwhile Japanese engineers, whose companies dispatched them for extended visits to Bitzer's lab, went home to an electronics industry that today dominates the development and manufacture of plasma displays. What happened to the flat screen from the flatlands?
Blue and orange beginnings
At that time, almost all devices for interacting visually with computers
were alphanumeric displays that could only render letters and numbers,
not the graphics required for teaching and learning many subjects. Bitzer
rigged a system using radar display tubes that could digitally read
pictures and alphanumeric characters from ILLIAC I, then transmit the
images by cable to TV terminals at each student station.
The system worked well enough while PLATO was in a proof-of-concept
phase. However, the constant refreshing of the image that is required
in a cathode ray tube, while fine for TV, didn't lend itself well to
the sustained display required for graphics. The tubes had no memory
for holding an image, and the cheap computer memory that makes tubes
suitable for graphics today was a dear resource in the 1960s. PLATO
would require a better display for the long haul.
Bitzer enlisted Willson, then a graduate assistant, and Slottow, then
a research engineer, in the task of exploring how a matrix of discrete
neon cells might be driven by a high-frequency ac current, using capacitors
at each cell so that individual cells, or pixels, could be addressed.
The big breakthrough came one summer evening as Bitzer and Slottow waited
outside CSL for their wives to pick them up after work. They began discussing
the project in terms of its barest essentials and realized that the
simplest configuration would be to exploit the natural capacitance of
the glass on either side of a panel, which could be done by placing
electrodes on the outside of each cell, separating the driving current
from the gas.
Next morning, the team set about building a new device. With Willson doing most of the handiwork, they ultrasonically drilled a hole fifteen thousandths of an inch wide into a thin glass slide, then sandwiched that slide between two others. They deposited thin-film gold electrodes on the outside surfaces to carry a high-voltage driving source. They sealed the sandwich with epoxy on three sides and glued it to a vacuum pump on the fourth, then pumped it clean and backfilled it with neon.
Power on. Blue. It was July 1964, and the first ac plasma display panel
had been built. The panel's single cell operated on the fundamental
rules that govern the millions of cells in one of today's panels.
After this initial success, the team learned that nitrogen from the air had leaked into their cell, accounting not only for its blue hue, but also for its good "memory margin"-its property of remaining lit in the presence of a "sustain" voltage significantly lower than the "breakdown" voltage necessary to initiate the discharge. By 1967, the inventors had figured out how to achieve good memory margin using just neon, and they had developed the driving circuitry necessary to address a large array of pixels. (Alpert had kept Bitzer's research under his wing after becoming graduate college dean in the mid-1960s. After the move, Bitzer's lab was renamed the Computer-based Education Research Laboratory.) That year, they built a 16 x 16 panel that glowed orange, thanks to the purer neon mixture. PLATO screens and other plasma panels for years to come, here at the U of I and beyond, would radiate the same orange.
Although the first patent covering the fundamental operation and applications
of the plasma display panel was not granted until 1971 ("one of
the most complete applications I think I've ever done," recalled
Scarpelli), U of I began collecting on the technology as early as 1967.
That year U of I sold an exclusive license to the Owens-Illinois glass
company, which would deliver the first commercial-grade "Digivue"
displays for use in PLATO in 1971.
IBM took an early interest as well, and the lure of Big Blue's prestige and deep pockets forced Merriam and Alpert into some ticklish negotiations between the two corporate players, with the happy result that U of I collected a million dollars from IBM in exchange for another license. That license would lead in 1983 to the IBM 3290 Information Panel, "the industry's first mass-produced, large-screen plasma display terminal for commercial use," according to an IBM advertisement.
TV companies including RCA, Zenith, and General Electric took notice
of early press reports about plasma displays as potential "hang-on-the-wall"
TVs. Some took out licenses, but they all sent visitors to see what
was happening at CERL. Zenith provided the phosphors for Edward Stredde's
(BSEE '66, MSEE '68) master's work on a multicolor plasma display.
After finishing his PhD in 1975 with a dissertation on the discharge
dynamics of plasma displays, Weber joined the CERL staff and began consulting
to U.S. companies interested in such commercial applications of the
Another CERL alum, Roger Johnson (BSEE '65, MSEE '66, PhD '70) joined
the ECE faculty in 1971 and found his consulting home in the Pentagon
and its contractors, which included Magnavox, Science Applications International
(now SAIC), and the Owens-Illinois spin-off Photonics Systems. Johnson
would leave his faculty post in 1977 and spend the next 25 years at
SAIC developing flat displays and mobile workstations.
In 1982, the company manufactured its "Plasmascope" displays
for controlling ground-launched cruise missiles. The displays were "nuclear
hardened" to withstand the radioactive environment of a nuclear
war. Similar displays went into the Trident nuclear attack submarine
and the "Doomsday Plane"-officially known as the Advanced
Airborne Command Post, a Boeing 747 outfitted to control U.S. forces
in a nuclear war. Photonics and Magnavox collaborated on the largest
plasma displays of the time, status boards used by the Air Force to
monitor air operations.
Japanese companies were among the first to take out licenses and begin
their own plasma display research, enjoying the support and encouragement
of NHK, the government broadcasting system that had advocated HDTV as
early as the 1960s. Among the prominent Japanese engineers who visited
CERL to study plasma displays was Heiji Uchiike, now of Saga University.
Uchiike spent a year at CERL in the early days of the plasma display
and has gone on to train many of the top plasma engineers in Japan.
Japanese companies who sent visitors to CERL, many of them staying for
extended periods, include Fujitsu, Hitachi, Matsushita, Sony, NEC, and
even NHK. These companies, especially Fujitsu, have made important developments
based on the fundamental ideas that came out of Illinois.
Bitzer noted that the Japanese also saw plasma as an answer to the problem of displaying their Kanji script, something the Western alphanumeric computer displays of the early 1960s could not do. So plasma panels became widely used in Japan for cash registers, meters, and public signs.
In the red
Weber had derived most of his income from consulting on the commercial
side, so there wasn't a lot left to do when IBM closed its plasma manufacturing
plant in Kingston, NY. Except perhaps to join forces with three former
IBM executives, buy the used equipment from the plant (88 trailer truckloads
of it), haul it to an old apple juice factory in nearby Highland, and
hang up a shingle. Which is exactly what he did.
Plasmaco was also a U of I project in technology commercialization.
Weber remained on the CERL staff while serving as chief technical officer
of the company, and many Plasmaco staff visited CERL for training. The
university licensed Plasmaco to use its plasma technology, which now
included energy-efficient driving circuitry developed by Weber himself.
(Every plasma TV on the market now incorporates Weber's contributions,
which are the subject of an ongoing legal dispute between U of I and
In 1990, Weber moved to New York and assumed full-time duties at the
new company, which scraped by producing monochrome plasma computer displays
until 1993. But by that time, liquid crystal displays had achieved color
and conquered the market. Plasmaco now faced foreclosure, and the company's
investors shook up the top management, making Weber president and CEO
and forcing him to fire half his staff. "Things got very ugly with
all the creditors that were after us," recalled Weber. "The
sheriff was knocking at my door because we couldn't even show up for
court. The lawyers wouldn't represent us because we hadn't paid them."
Weber convinced a banker to lend him $80,000 for components to begin developing a color display. By the last day of a 1994 industry convention in San Jose, CA, he was able to rig a static display of colored stripes that impressed people with its brightness and contrast ratio. Weber then began a joint development program with Matsushita, which bought Plasmaco in 1996 for $26 million, leaving Weber in his position as president. Weber hired his old student Bill Schindler (MSEE '82) to manage Plasmaco's 60-inch prototype project, unveiled in 1999 and widely agreed to have the best contrast ratio in the industry.
Isn't that beautiful?
Projection systems have spatial limitations of their own caused by
the placement of the projector and screen, and they require a dark room
for good results. Liquid crystal displays have the advantage of thinness
(that's why they are great for laptops), but they are not as bright
as plasma displays, they can't yet be made as wide, and their pictures
disappear when viewed from the side.
Johnson is more optimistic about U.S. leadership in the further development
of plasma displays. Now retired from SAIC, he has gone back to running
his old consulting company, which is incorporated in Illinois. Johnson
believes Illinois can have "a second round at the plate, and maybe
hit the ball again." He is interested in partnering with current
ECE faculty and students who are conducting research relevant to plasma
For example, Professor Kevin Kim's lab is perfecting "microspheres"
that may be useful for evenly depositing materials in plasma display
manufacturing. Phil Krein developed an energy-saving power supply for
plasma displays. And Mark Kushner developed software for simulating
the physical dynamics of plasma cells. Johnson would also like to organize
a seminar series on flat-panel displays at U of I.
"The press kept telling me that I was wrong, that it was going to be the future television," recalled Bitzer. "But that was not my heart. My heart was the education." Bitzer must now concede that the press was right, but he can still point to Weber's 60-inch wonder with all the pride of a new grandfather: "Did you ever see a display like that? Isn't that beautiful?"
Daniel Alpert, Brij Arora, Kevin Kim, Nate Scarpelli, Bill Schindler,
and Robert Willson assisted in preparing this article. Special thanks
go to Don Bitzer, Roger Johnson, and Larry Weber for their generous