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Blue LEDs (Light Emitting Diodes) and Lasers based on GaN semiconductor
compounds represent one of the most important breakthroughs in electronics
and opto-electronics of recent years. GaN based LEDs have started to
replace traditional light bulbs in traffic lights and are likely to gain
an ever increasing market share for many other lighting applications. GaN
based blue lasers allow data storage with much higher density than
traditional red lasers. In addition, there are many less obvious
applications in medical fields including diagnostics and other areas.
This presentation gives an overview of the most important points of GaN
LEDs and lasers, of the key steps which led to this breakthrough and an
overview of this field.
This report is based on a presentation first given by the author on
August 29, 1995 to US Senator Jeff Bingaman in Tokyo, and later at
Hewlett-Packard Research Laboratories in Palo Alto, at Princeton
University and at other locations.
- Blue LEDs and lasers - key points
- Why are blue GaN LEDs important?
- Why are blue GaN lasers important?
- Who invented GaN blue LEDs and Lasers?
- Physics and technology
- Light spectrum of an LED, a light bulb and a laser
- Blue lasers for optical storage
- What is a blue light emitting diode (LED)?
- What is a laser diode (LD)?
- Surface emitting lasers (VCSELs) vs edge emitting lasers
- What is a light amplifier?
- What is a resonant cavity?
- Why Gallium Nitride?
- The three steps to commercial GaN devices
- Three key difficulties had to be solved
- Lattice mismatch
- High growth temperature
- P-type doping
- Some remaining issues
- Long-lifetime GaN lasers
- Development of long-lifetime GaN lasers
- Schematic structure of Nakamuras blue laser
- Schematics of ELOG for defect control
- Why did Shuji Nakamura at Nichia succeed where many much larger
corporations failed?
- Management structure for Nakamuras work
- About Nichia Chemical Industries
- Nichia sales, profits and number of employees (data for 1983-2004)
- Market for GaN LEDs
- Applications and markets for GaN LEDs
- (A) LEDs for traffic signals
- (B) LEDs for displays
- (C) Automotive applications, LED roadmap of a major Japanese car
electronics maker, LED head lights and fog lamps
- (D) white LEDs for lighting
- Market for GaN Lasers
- Applications and markets for GaN lasers
- Blu-ray disc and ND-DVD (AOD)
- Patent issues
- Selected US Patents issued during 1993-1995
- Nichias patents
- "The Big Five"
- Recent court cases between Shuji Nakamura and Nichia Chemical
Industries and implications
- Recent court cases between Shuji Nakamura and Nichia
- Implications
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