draper prize program 4-24-12
TRANSCRIPT
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Reflectionsof Dr. Martin SchaDt
Upon the occasion of his 2012 Draper Prize LectureApril 24, Boston Museum of Science & Cambridge Science Festival
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I grew up in a small country
village in the northern part o
Switzerland where, in the 1940s
and 50s, no one ever thought
o going to university, including
mysel, even though I made many
daring physical and chemical
experiments. Admittedly, some
experiments were not appreciated
by our neighbors, especially
when they interered with
radio reception or were o noisy
pyrotechnical nature!
Since I did not have a camera
when I was young, I have no
pictures o my early experiments.
Today I regret this because some
o my early electronic tube radios
and transmitters looked quite
interesting, aintly resembling
haystacks. I made my experiments essentially with bits and pieces rom scrap radios (the
unit price o a scrap radio was $5, which was a small ortune at the time). Precautions
to saeguard the operator rom electrical shocks were not considered. Later, havingearned some money during my apprenticeship, I was able to build more sophisticated
transmitters and even buy a small Hallicraters short-wave radio.
Since university was not an obvious
alternative, I began a our-year
apprenticeship as an electrician in
Basel, the oldest university town in
Switzerland (ounded 1460). I very
quickly realized that I wanted to learnmore about science, so I caught up on
studies at evening school and passed
Dr. Martin Schadt
Physicist and Inventor 2012 Draper Prize Recipient
Dr. Martin Schadt in his Roche Lab in 1988.
One of Schadts (illegal) short-waveradio stations (1954).
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my entrance exams or university. Having a keen interest in experiments, I was especially
ascinated by physics and its technological implications.
While pursuing my masters degree in experimental physics, I became interested in
organic semiconductors, quite an exotic topic at the time. I liked the interdisciplinary
research approach and the reedom to design and prepare my own experiments and
equipment. Few groups world-wide were doing research on organic semiconductors, and
the only regular lecture on solid-state physics at the University was oered by my thesis
advisor, Proessor E. Baldinger. He was an outstanding teacher in solid-state electronics,
both encouraging and supporting unconventional research projects.
Ater completing my thesis in 1967, I
was granted a two-year postdoctoral
ellowship at the National Research
Council (CNRC), Ottawa, Canada. In the
group o D. F. Williams, I continued my
research on electronic charge-transport
and related optical properties in molecular
crystals. Because o the inecient
charge carrier injection into organic
crystals a prerequisite or electron-hole
recombination and generation o lightemission I developed more ecient
hole-injecting electrodes. These new
Now, as so oten happens
in physics, new surprising
ndings were made! Contrary
to initial thought, I could show
ater numerous experiments
that it was not necessary
or the electric eld to ullyunwind the liquid crystal helix.
Schadts rst TN-LCD prototype made in 1971 to convince the Roche
Board of Directors of the operability of the Twisted Nematic (TN)-Effect.
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solid-state electrodes permitted electrically
insulating organic materials to be converted
into considerably ecient light-emitting organic
semiconductors. This paved the way or newoptical and electronic experiments.
One problem was that the electrodes were highly
sensitive to residual water, which limited their
lietime to seconds in an ordinary lab atmosphere.
Ater having remedied this problem, I successully
developed the rst solid-state organic light
emitting display (OLED), which led to my rst
U.S. patent. Due to the 1mm-thick anthracenesingle crystal that I used, more than 100V were
required to generate sucient light output rom
the display. This voltage was much too high or
semiconductor drivers.
My two-year ellowship ended at this stage.
Discouraged by the large gap between the
perormance o my simple OLED prototype and
industrial targets, I elt pessimistic about the
uture o organic semiconductors and decided to
switch elds. In act, it wasnt until 25 years later,
ater chemical vapor deposition (CVD) had been
developed, that C.W. Tang and S.A. VanSlyke at
Kodak demonstrated that ecient low voltage
operation o OLEDs was possible by using very
thin (
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Wolgang Helrich, who had
let RCA to join the Roche
liquid crystal group. Inspired
by a polarization observa-tion made by the French
crystallographer Mauguin in
1911, Helrich had the idea
that the long axes o ini-
tially twisted nematic liquid
crystal molecules between
crossed polarizers could be
switched by an electric eld
perpendicularly, causing anoptical change.
Contrary to the lack o
interest shown by RCA
management towards this
idea, I was immediately
attracted and began to design and perorm a series o electro-optical experiments
or investigating its easibility. In the late all o 1970, I was able, or the rst time, to
reproducibly switch and observe polarization changes in a twisted nematic LC-congurationunder the microscope. Now, as so oten happens in physics, new surprising ndings were
made! Contrary to initial thought, I could show ater numerous experiments that it was
not necessary or the electric eld to ully unwind the liquid crystal helix, i.e. to switch the
long molecular LC-axes vertical to the cell substrates. To my own astonishment, I ound
that a ew volts were sucient to block light transmission. This was a more than 20-
times lower voltage than we had initially expected to be required or complete vertical LC-
Dr. Martin
Schadt in
his Roche
Lab in 1979.
First page of the Swiss TN-LCD patent of Helfrich and Schadt,led Dec. 4, 1970.
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alignment. The experiments showed that it is enough or the electric eld to deorm only
the central part o the TN-helix to achieve an electro-optical eect. We patented the
new eect on December 4, 1970, which became known as twisted nematic (TN)-eect,
and published the surprising results. A theory describing the electro-optics o twisted
nematic LC-congurations did not exist at the time. It was only developed three years
later by Dwight Berreman at Bell Labs, NJ. In the same year, Peter Brody realized the
rst thin-lm transistor (TFT)-addressedTN-LCD.
With the exception o two years
o research in biophysics due to
interruption o liquid crystal research
by Roche in 1971 my R&D activities
ocused on the development o
electro-optical eld-eects or liquid
crystal displays and new, industriallyviable liquid crystal materials. The
TN-invention was licensed world-
wide by Roche to the emerging liquid
crystal (LCD)-industry. TN-LCDs
initiated a paradigm change rom
dynamic scattering displays towards
todays fat panel eld-eect liquid
crystal display industry. I supported
this development with my teamby advancing the experimental
techniques or determining all relevant
LC-material properties, searching
or correlations among molecular
Drs. Schadt and Helfrich received the
Munich and Aachen Prize for Technology
and Natural Sciences for invention of the
TN-LCD, Berlin, 1994.
First page
of the TN-
LCD patent
granted in
Japan (which
looks very
picturesque).
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structures, display perormance, and materialproperties. As a result, the pharmaceutical
company, Roche, established itsel as a major
liquid crystal supplier or the emerging LCD-
industry. Moreover, I invented the linear
photo-polymerization technology with my
collaborators in 1991, enabling alignment and
optical patterning o monomer and polymer
liquid crystals on suraces by light rather than
mechanically. The technique opened up novelLCD operating modes with broad elds o
view and short response times. New optical
polymer thin-lm applications became easible.
Examples include high resolution patterned
A Polarization Microscope picture of one ofSchadts rst TN-LCD experiments made at
Roche in the fall of 1970 which virtually failed.
The picture looks like a work of art rather than
an element of a TN-LCD. Some of the black
parts in the picture, however, showed signs of
an electro-optical effect; i.e. optical switching
upon voltage application.
optical retarders or 3D-LCDs,
polarization sensitive optical
security elements, and optically
anisotropic integrated opticsdevices, among others.
I headed the Liquid Crystal Re-
search Division o Roche until
1994. Based on the photo-align-
ment technology, my Division was
spun out as the company ROLIC
Ltd, an interdisciplinary Research
and Development Companywhich I headed as its rst CEO
and delegate o the Board o Di-
rectors until my retirement rom
the operating business in 2002.
Since then, I have been active
as an independent inventor and
scientic advisor to research
organisations and industry. I
am a Fellow o the Society o
Inormation Display and o the
European Academy o Sciences,
holding more than 106 U.S.
patents. I have published 182
papers in leading scientic
journals. Among other awards, I
am the recipient o the IEEE Jun-
Ichi-Nishizawa Medal and the2012 Draper Prize.
In my Draper Prize Lecture at the
Museum o Science, Boston, in
April 2012, I presented the his-
torical development o todays
eld-eect LCD and LC-mate-
rial technologies as well as the
world-wide interdisciplinary con-tributions o physicists, engineers
and chemists to the successul
story o fat panel displays.
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Electro-optical Response of Lipid Membranes
Because Roche as a pharmaceutical company was interested in cell mechanisms/
interactions and because I had decided to stay with the company ater Roche
stopped nematic LCD R&D in 1971, I started looking or interesting problems in
the eld o articial molecular bilayer membranes (black lipid lms).
Since atty acids exhibit liquid crystalline properties, this enabled combining my
interests in electronic transport phenomena and electro-optical eects with bio-
physics. Lyotropic LCs (atty acids) are essential components o our cell mem-
branes. Without their liquid crystalline long range order, blood cell membranes,
or instance, could not exist.
When I started reading biophysics literature to get ideas or experiments, I came
across a publication by an MIT proessor who had investigated the electro-optical
response o lipid bilayer membranes doped with vitamin A acid. He explained hisresults with a semiconductor band model. As a solid-state physicist, this puzzled
me because an important prerequisite or band models is a periodic lattice made
up o a very large number o atoms/molecules in transport direction. Because bi-
layer membranes consist o just 2 molecules in transport direction, I did not under-
stand his results and conclusions. Thereore, I decided to repeat his experiments.
Ater several months o hard work and struggling with tricky experimental condi-
tions, I discovered that he was indeed wrong. He had not measured cell mem-
brane eects but the optical response o his electrolyte/electrode combination.
I developed an electronic analogy model o the photo-response o lipid bilayermembranes doped with Vitamin A, which properly explained the experiments, and
was lucky to publish my rst work in biophysics research in a renowned journal:
M. Schadt. Photoresponse o bimolecular lipid membranes pigmented with retinal
and vitamin A acid, Biochimica and Biophysica Acta, Vol.323, 351-366, 1973.
The Effects of Neurotransmitters on Electrical Brain Response
Based on my earlier PhD work on charge carrier transport in molecular crystals
and rom a comment o a chemist riend who mentioned that Roche manuac-
tured ionophores (molecules which transport ions across cell membranes) in the
U.S. to prevent chickens in large arms rom catching a deadly disease, I thought
Ventures into Biophysics Research
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this topic would be interesting. Wondering whether I could dope my
membranes with this ionophore to nd out which type o ions were re-
sponsible or the chicken eect, I discovered interesting correlations.
And I was just about to write up the results or publication when I met
a neurologist in the medical research department o Roche who used
the same ionophore to extend the lie o his dogs in his studies o theeects o neurotransmitters on electrical brain response. I wondered
whether the ion selectivity ound in my membranes would correlate
with neurotransmitter transport and started to extend my experi-
ments to neurotransmitters. The results were very interesting indeed.
I ound that not only ion transport was selective, but that neurotrans-
mitter transport across ionophore-doped membranes was selective
as well. The next step was to investigate whether the specic neu-
rotransmitters which my colleague ound most ecient in his dogswould also be most ecient in my experiments, which was the case.
This was an exciting result because it showed that experiments with
simple bimolecular membranes can correlate with the mechanisms in
complex living cell membranes. We published the results in:
M. Schadt and G. Husler, Permeability o lipid bilayer membranes to
biogenic amines and cations: Changes induced by ionophores and cor-
relations with biological acitivites, Journal of Membrane Biology, Vol.
18, 277-294, 1974.
And, What If?
At this stage o my short but very interesting biophysics R&D time,
and because Seiko Epson had approached Roche in the meantime to
license the twisted nematic (TN)-LCD patent rights, Roche suggested
that I restart interdisciplinary LCD- and LC-material research which
had been stopped in 1971. Apart rom its world-wide TN-licensing
activities, Roche became a major LC-material supplier or the emerg-ing LCD industry.
Sometimes I wonder what would have happened i I had continued
working in biophysics; well, unortunately one lives only once.
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The Draper Prize was instituted by
the National Academy of Engineering
in 1988 at the request of Draper
Laboratory to honor Dr. Charles Stark
Draper and increase public awareness
of the contributions of engineering to
society. The prize is awarded annually
for innovative engineering achievementsand their reduction to practice in ways
that ultimately have improved the well-
being and freedom of humanity.
For more information, visit
www.draperprize.org.
www.draper.com#*