Lighting of the Future: Dielectric Barrier Discharge Lamps

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Lighting of the FutureDielectric Barrier
Discharge Lamps

• Presented by Christopher Sollars
• Mentor Dr. Feng Jin

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Overview

• What is a Dielectric Barrier Discharge?
• Lamps and Other Common Uses
• Advantages of DBD lamps
• Future Potential
• Conclusions

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What are Dielectric Barrier Discharges?

• Dielectric Barrier Discharge (DBD) was originally
  developed in 1857 by Werner von Siemens as a
  method of ozone production.
• DBDs are characterized by the presence of one or
  more insulating layers (dielectrics) in the
  current path between metal electrodes in addition
  to a discharge air gap.

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What is DBD?

• Capacitive coupling of the dielectrics require
  alternating electric field to drive displacement
  current (cannot run on DC voltage inputs).
• Discharge gaps usually consist of pressurized
  gas. The type of gas depends on the application.

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What is DBD?
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What is DBD?

• Random, short-lived, narrow filamentary channels,
  or micro discharges, across the discharge gap
  when voltage is applied.
• Micro discharge channels deposit charge and
  spread it over the dielectric surface.
• Snuffed out by the field created by
  accumulating charge on the dielectric

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DBD LampsProduction of UV Light

• In micro discharge channels, collisions between
  electrons and rare-gas atoms (xenon, krypton,
  argon, etc.) lead to excited atoms.

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DBD LampsProduction of UV Light

• At high pressures these atoms react to form
  intense sources of vacuum ultraviolet radiation
  (VUV).
• This UV radiation is then converted into visible
  light with the use of special phosphor coatings.

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DBD LampsProduction of UV Light

• DBD lamps use a variety of varying frequencies
  and waveforms.
• UV production efficiency is increased by a factor
  of 3 using fast excitation pulses instead of a
  traditional sinusoidal input.
• These pulses (lt1µs) are followed by idle periods
  (100µs).
• This allows the micro discharges to funnel out
  and be more cone-like at the dielectric surface.

High-peak-power finger lamp _at_ 172nm
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DBD LampsProduction of UV Light

• Xenon has been proven in studies to be the most
  efficient halogen gas used.
• Efficiencies have reached nearly 40

DBD lamp for plasma diagnostic testing
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Common Uses for DBDs

• Ultraviolet light emission
• Ozone generation by dissociating oxygen molecules
• Pollution control by destruction of poisonous
  compounds
• Surface modification by plasma treatment (curing,
  etching, etc.)
• Lighting sources

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Osram Planon DBD Lamp

• 1st DBD based lamp
• Manufactured 2002
• Xenon filled
• Life 100,000hrs (50 lumens)
• Mercury-free
• 8.5 mm thickness
• FLAT!!!
• LCD and X-ray backlighting

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Why DBD Lamps Over Conventional Fluorescent?

• DBDs are mercury-free, eliminating environmental
  concerns.
• Dielectric barriers shield electrodes sustaining
  longer life.
• Varying geometries

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Future Potential

• DBD technology has found its way into MILLIONS of
  flat panel plasma televisions and viewing
  screens.
• DBDs have not reached the luminance and
  efficiency of Mercury-based fluorescent lamps.
• Research includes
• Developing more efficient phosphor coatings for
  UV conversion
• Experimenting with different gas pressures and
  pulsed excitation techniques

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Conclusions

• Dielectric Barrier Discharge technology is based
  on ideas formed before the Civil War.
• The number of applications for Dielectric Barrier
  Discharge continue to grow.
• Perhaps one day, this technology will render
  mercury-based lighting obsolete.
• DBD lamps are already the center of some key
  innovations of the 21st century.

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Acknowledgements

• Dr. Feng Jin
• U. Kogelschatz (2000), Fundamentals and
  Applications of Dielectric Barrier Discharges
• http//mmlab.dlut.edu.cn/plasma-16
• Osram Planon (2004), Planon Dielectric Barrier
  Excimer Lamp, http//www.lamptech.co.uk/Spec20Sh
  eets/Osram20Planon.htm
• Richard P Mildren (2004), Dielectric Barrier
  Discharge Lamps http//www.physics.mq.edu.au/rmi
  ldren/DBDs.html
• Masafumi Jinno, Hideki Motomura, Yoshihisa Ikeda,
  and Masaharu Aono, (2003), Fundamental Research
  on Xenon and Xenon-Rare Gas Pulsed Dielectric
  Barrier Discharge Fluorescent Lamps
  http//www.icpig.uni-greifswald.de/proceedings/dat
  a/Jinno_1