Lighting, Lasers, and Their Econoimcs

A/Prof Jeffrey Funk
Division of Engineering and Technology
Management
National University of Singapore

Objectives
 What are the important dimensions of performance
for lighting, lasers and their higher level systems?
 What are the rates of improvement?
 What drives these rapid rates of improvement?
 Will these improvements continue?
 What kinds of new systems will likely emerge from
the improvements in lighting and lasers?
 What does this tell us about the future?

Session Technology
1 Objectives and overview of course
2 When do new technologies become economically feasible?
3 Two types of improvements: 1) Creating materials that
better exploit physical phenomena; 2) Geometrical scaling
4 Semiconductors, ICs, electronic systems
5 MEMS and Bio-electronic ICs
6 Lighting, Lasers, and Displays
7 DNA sequencing and Nanotechnology
8 Human-Computer Interfaces
9 Superconductivity and Solar Cells
10 Deepavali, NO CLASS
This is Fifth Session of MT5009

As Noted in Previous Session, Two main
mechanisms for improvements
 Creating materials (and their associated processes)
that better exploit physical phenomenon
 Geometrical scaling
 Increases in scale
 Reductions in scale
 Some technologies directly experience improvements
while others indirectly experience them through
improvements in “components”
A summary of these ideas can be found in
1) forthcoming paper in California Management Review, What Drives Exponential Improvements?
2) book from Stanford University Press, Technology Change and the Rise of New Industries

Both are Relevant to Lighting (and lasers)
 Creating semiconductor, organic, and other materials that
better exploit the phenomenon of electroluminescence
 Increases in scale: larger wafers/production equipment
 Reductions in scale: smaller sizes lead to higher efficiency
LEDs, smaller packages and higher density lasers
 Some technologies directly experience improvements
while others indirectly experience them through
improvements in “components”
 Better LEDs and OLEDs lead to better lighting systems

Outline
Existing state of lighting
Light emitting diodes (LEDs)
Organic light emitting diodes (OLEDs)
Laser Diodes
Applications for Laser Diodes
Bioluminescence

Type of
Specs
Incandescent
Lamp
Fluorescent
lamp
LED OLED
Thickness Very Thick Very Thick 6.9 mm (for LED
TV)
1.8 mm
Flexibility Very inflexible,
and breakable
Very inflexible,
and breakable
Some flexibility Most flexible
Danger to eyes Can’t stare at
them
Can’t stare at
them
Can’t stare at
them
Okay to stare
Lifespan 500-700 hrs >10, 000 hrs 100, 000 hrs 15, 000 hrs
Price of 60 Watt
bulb
<1 USD <5 USD 9 USD Most expensive
Efficiency/
Brightness
300 USD/Year for
800 lumens
75 USD per
year
<10 USD per year Not yet efficient
Environmental
friendliness
Low efficiency Contains
mercury
Most efficient, no
toxic chemical
Not yet efficient,
no toxic chemical
Costs of LEDs have Rapidly Dropped
Source: Group presentation in MT5016 module and http://electronics.howstuffworks.com/led4.htm
http://www.theverge.com/2013/10/3/4798602/walmart-gets-aggressive-on-led-bulb-pricing

Incandescent Lights
 Electricity is generated
by voltage across
electrodes
 Poor efficiencies (most
of the power is emitted
as heat or non-visible
electro-magnetic
radiation)
 Also large size
 Big connector, bulbs,
filaments
Filament

Fluorescent Lighting
 Electricity also generated by
voltage across electrode
 Better efficiencies
 emits about 65% in 254 nm line
(visible) and 10–20% of its light in
185 nm line (UV)
 UV light is absorbed by bulb's
fluorescent coating (phosphors),
which re-radiates the energy at
longer “visible” wavelengths
 blend of phosphors controls the
color of light
 But still large device
 Bulb, Connector, gases

Outline
Existing state of lighting
Light emitting diodes (LEDs)
Organic light emitting diodes (OLEDs)
Laser Diodes
Applications for Laser Diodes

LEDs are basically a PN junction on a
Semiconductor Substrate
Voltage difference
causes electrons and
holes to recombine
and thus release
photons
Amount of energy
in photons (and thus
wavelength of light)
depends on band
gap

Typical LED Characteristics
Semiconductor
Material
Wavelength Colour VF @ 20mA
GaAs 850-940nm Infra-Red 1.2v
GaAsP 630-660nm Red 1.8v
GaAsP 605-620nm Amber 2.0v
GaAsP:N 585-595nm Yellow 2.2v
AlGaP 550-570nm Green 3.5v
SiC 430-505nm Blue 3.6v
GaInN 450nm White 4.0v
Different Materials for LEDs Emit Different Wavelengths
and thus Emit Different Colors

But other changes in materials lead to
improvements in efficiency
 One measure of efficiency is Photons per electrons:
first LEDs in 1960s generated .0001 photons/electron
 But efficiency is a vague term because our eyes are
more sensitive to some colors than others
 More popular measure of efficiency is lumens per
Watt; function of
 internal efficiency: amount of lumens generated
 extraction efficiency: % of lumens that actually escapes
 Must create the right combination of materials (and
processes) to achieve high luminosity per Watt
Orton, J, 2009. Semiconductors and the Information Revolution: Magic Crystals that made IT Happen, NY: Academic Press

Must find materials that
 Emit light in visible spectrum
 Have short radiative lifetime (high probability of
radiative recombination for electrons and holes)
 Minimize non-radiative recombination with high
crystal purity and structure
 Maximize the possibility of radiative recombination by
bringing together holes and electrons in a small space
(such as double hetero-structure or quantum well)
 And also design the device such that most of the light
is extracted, i.e., escapes

Improvements in Luminosity per Watt have Occurred
Source: Lima Azevedo, Granger Morgan, Fritz Morgan, The Transition to Solid-State Lighting,
Proceedings of the IEEE 97(3)
LuminosityperWatt

New Processes Also Helped
 Because these materials do not naturally occur and
because the processes impacted on the efficiency of an
LED, scientists and engineers also created new
processes for these new materials
 These processes include
 Liquid phase epitaxy
 MOVPE (metal organic vapor phase epitaxy)
 MBE (molecular beam epitaxy)
 Electron beam irradiation
 MBE allowed better control over the ratio of materials
and the structures of the devices

Most Recent Color is Blue
 Bottleneck for making white LEDs for many years was
in blue lasers (need red, blue, and green lights)
 Efficient blue lasers did not exist until Shuji Nakamura
improved the efficiency of blue LEDs in late 1990s by
using GaInN
 Blue LEDs enabled white LEDs and thus the use of
LEDs for lighting
 Second, blue lasers enabled smaller memory storage
areas in CDs because shorter wavelength than red
lasers
 Finally, he developed a new growth technique called
epitaxial lateral over growth, which enabled lower
dislocation densities in blue lasers

How to achieve White Color LED
 Mixture of Red, Green & Blue color
to get white color LED.
 Involved electro-optical design to
control blending & diffusion of
different colors
 Involved coating of an blue LED
with phosphor of different colors to
produce white light.
 Fraction of blue light undergoes the
Stokes Shift being transformed
shorter wavelength to longer
wavelength.
RGB White LED Phosphor Based White LED
LED Die
Phosphor
Phosphor Based White LED Spectrum of Phosphor LEDRGB Color Chart

Warm white
Cool white
Daylight white
Phillips and Samsung have created LEDs that emit 200 lumens and they
oncluded that maximum theoretical efficiency is 400 lumens per Watt.
//www.greentechmedia.com/articles/read/philips-ups-led-ante-with-2
lumens-per-watt-tube. http://www.ledinside.com/node/16905
Further Improvements in Efficiency Have
Continued to Occur and More are Still Possible
According to DoE, Phillips, and Samsung

DoE’s Projected Increases in Efficiency of LEDs

Fluorescent
Source: Lima Azevedo, Granger Morgan, Fritz Morgan, The Transition to Solid-State Lighting,
Proceedings of the IEEE 97(3), March 2009
More Detailed Projections for LEDs by DoE

Source: Roland Haitz, Jeffrey Tsao, Solid-state Lighting: The case 10 years after and future prospects,
Phys. Solidi A 208 (1): 17-29, 2011
Costs are also Falling (Dotted Line) due
to Greater Efficiencies and Changes in Scale

Through-hole LED
 Lead frame based
 Advantages
➢ Low cost & easy rework
➢ Higher mechanical shock resistant
➢ Better light extraction with optic
designed viewing angle
 Disadvantage
➢ Size
 Printed Circuit Board based
 Advantages
➢ Size, thickness
➢ SMT process, more popular
 Disadvantage
➢ Less immunity to environmental
➢ No optic design, customized viewing
angle
➢ Complicated process
Surface Mount LED
Both reductions (smaller LEDs) and increases in scale
(bigger wafers/equipment) drive Cost Reductions

*See fourth session on ICs and discussion of displays for more details on why costs fall as substrates
and equipment are made larger. Wafers for ICs are now 12” and will soon be 18”
Source of figure: http://www.electroiq.com/articles/sst/2012/02/led-manufacturing-highlights-from-strategies-in-light-day-2.html
Wafer Sizes Have and Will Become Larger*

LED CFL Incandescent
Light bulb projected lifespan 50,000 hours 10,000 hours 1,200 hours
Watts per bulb (equiv. 60
watts)
10 14 60
Cost per bulb $35.95 $3.95 $1.25
KWh of electricity used over
50,000 hours
500 700 3000
Cost of electricity (@ 0.10per
KWh)
$50 $70 $300
Bulbs needed for 50k hours
of use
1 5 42
Equivalent 50k hours bulb
expense
$35.95 $19.75 $52.50
Total cost for 50k hours $85.75 $89.75 $352.50
Relatively Recent Cost Comparison
But most recent price < $10 (USD) for LEDs
Sources: http://www.tomsguide.com/us/light-bulb-guide-2014,review-1986.html;
http://www.tomsguide.com/us/light-bulb-guide-2014,review-1986.html
$9
$9
$59

Can’t
we design
and package
LED lights
any better
than this?

Two LED-based Decorative Lights
Available in Singapore

LEDs for Greenhouses?
 Greenhouses enable more locally grown food, and thus
lower transportation costs
 Build greenhouses in cities, something like vertical
farms?
 LEDs make more light available for greenhouses in
northern climates and thus increase their productivity
http://nextbigfuture.com/2014/06/greenhouses-will-get-more-energy.html#more

Intelligent Lighting and (Heating)?
 Easer to control LEDs via Internet with for example,
tablet or smartphone
 Can set timing, adjust colors and brightness
 Various hardware are needed
 but getting cheaper due to better electronic components
 may be economical in office or other commercial buildings
 How about using electronics to sense presence and
location of humans?
 Lights automatically turn on and off as people move
 Take this one step further: lights only illuminate spots
where people are standing or looking
 Lighting as a service
Source: Technology Review, Nov 5, 2012. http://m.technologyreview.com/blog/guest/28396/

Intelligent Heating with Infra-Red LEDs
 Direct beams of infrared light at people using
 Clever optics
 Servo-motors
 Infrared light heats people and reduces need for
heating entire room
 Large infrared lamps?
 Or small infrared LEDs?
 People tracked with image sensors or Wi-Fi
 Useful for large open rooms (e.g., lobbies, atrium,
lecture halls) or rooms rarely used
 Can reduce heating costs by 90%
Economist, in the moment of the heat, economist, September 6, 2014

Market for LEDs is Changing from Industrial Applications to General
Lighting as US bans sale of 40 and 60Watt Incandescent Bulbs
Source: http://www.semiconductor-today.com/news_items/2012/AUG/LED_090812.html

http://www.ledinside.com/node/17226; April 24, 2013

OLEDs have many Advantages
 Cheaper to process than semiconductor materials
 Lower temperatures required
 Can be roll printed onto a substrate (see later slides in this
session)
 Can put multiple colors on the same substrate
 Can stare at them, unlike other forms of lighting
 Thinner and more flexible
 These advantages enable more aesthetically appealing
designs, even more than LEDs
 But they currently have higher cost, lower efficiency and
shorter lifetimes than do LEDs

What about Organic LEDs (OLEDs)
Improvements in OLEDs are Occurring
Source: Sheats et al, 1996, Organic Electroluminescent Devices, Science 271 (5277): 884-888 and Changhee Lee’s
presentation slides; PPV: poly (p-phenylene vinylene)

More Recent Data
 Improvements also continue to be made. According to a 2009
paper in Nature, a novel structural design for a white OLED is
described that exhibits efficiencies of 90 lumens per watt and
shows a potential for efficiencies as high as 124 lumens per
watt
 Panasonic announced a white OLED with 114 lumens per
Watt in 2013
 Philips claims that efficiencies of 150 lumens per Watt can
and will likely be achieved in the near future.
http://www.technologyreview.com/news/413485/ultra-efficient-organic-leds/
http://panasonic.co.jp/corp/news/official.data/data.dir/2013/05/en130524-6/en130524-6.html

Improvements are Driven by Creating
Materials…..
 Creating materials that better exploit the
phenomenon of electroluminescence is the
main reason for the improvements shown in
the previous slide
 Nitrides
 Polymers
 Polyfluorene
 Also new processes?

What are the limits?
 To what extent can
 efficiencies be improved?
 costs be reduced?
 thinness be achieved?
 Lifetimes be increased?
 Are these limits determined by materials or
processes?
 Can roll printing dramatically reduce costs; can
increasing scale of roll printing equipment lead
to much lower costs?

Where will be the first application for
OLEDs
 Ones that require thinness, flexibility, and/or
multiple colors on a single substrate?
 Household lighting?
 Retail lighting?
 Clothing?
 Displays?
 How many improvements are needed before
these applications become economically
feasible?

Retail Lighting Display
New forms of eye
catching layouts
New types of Signs

Clothing
Flexible light panels sewn on clothing can provide
brighter luminance compared to conventional
safety clothing

Outline
 Existing state of lighting
 Light emitting diodes (LEDs)
 Organic light emitting diodes (OLEDs)
 Laser Diodes
 they are similar to LEDs
 They are basically an LED with a cavity and a
mirror to enable “optical amplification based
on stimulated emission of photons”
 Applications for Laser Diodes
 Bioluminescence

Semiconductor Lasers also benefit from the
two mechanisms mentioned earlier
 Creating combinations of materials that better exploit
phenomenon of optical amplification based on stimulated
emission of photons
 Helped by new processes that enable higher purity, better
crystal structure, and better control over composition of
materials
 Also better materials for heat sinks, solder, and mirrors
 Increases in scale: larger wafers/production equipment
 Reductions in scale: smaller sizes generally lead to lower
threshold current densities (helped by new technologies)

Different materials emit light at different wavelengths
Laser types shown above the wavelength bar emit light with a specific
wavelength while ones below the bar emit in a wavelength range. Non-
semiconductor lasers (many kinds of lasers) are also shown in this figure

Many Improvements to Lasers
 Reductions in threshold current, i.e.,
minimum current needed for lasing
 Reductions in Pulse Width of Lasers for
faster switching
 Increases in Power of Lasers
 Improvements in cost and power for one
type of laser (GaAs)

Source: Materials Today 14(9) September 2011, Pages 388–397
Reductions in Threshold Current, i.e., Minimum Current Needed for
Lasing to Occur, enable lower power consumption

Reductions in Threshold Current Driven By:
 New structures
 Double hetero-structure
 Quantum wells
 Quantum dots
 Reductions in scale
 These new structures involve smaller dimensions
 Reductions in scale for a specific structure (along with
other changes) also led to reductions in threshold
current density
 Reductions in scale also lead to lower costs in the long
run

Double Heterostructure Quantum Well
(edge emitter) (edge emitter)
Vertical Cavity Surface Emitting Laser (VCSEL) (emits from the top and
emits perpendicular to the top surface), cheaper to fabricate than others

Source: NTT develops current-injection photonic-crystal laser
http://www.physorg.com/news/2012-02-ntt-current-injection-photonic-crystal-laser.html
DFB: Diffraction
Feedback Laser
VCSEL: Vertical
Cavity Surface
Emitting Laser
Lower operating currents also for VCSEL

Reductions in Threshold Current (2)
 Creating new combinations of materials; enabled both
 new emission wavelengths and
 better lasing at a single wavelength (purity and crystal
strength are important: see next slide)
 New processes supported the reductions in scale and
the creation of better materials
 Liquid phase epitaxy
 Vapor phase epitaxy
 Molecular beam epitaxy
 Metal organic vapor phase epitaxy
 Low pressure chemical vapor deposition

Reductions
in Pulse
Width
of Lasers
http://www.nature.com/
nature/
journal/v424/n6950/fig
_tab/nature
01938_F2.html

Improvements in Power of Other Lasers for Defense, Medical
(without affecting
eyes)
Yb: Ytterbium
Tm: Thallium
Er:Yb: Ytterbium-
sensitized erbium
http://spie.org/x26003.xml

Source: Ultrafast fiber lasers, Marting Fermann and Ingmar Hart, Nature Photonics, 20 Octobers 2013, 868-874
Using Multiple Fibers can Enable Even Higher Power Output

Many Improvements to Lasers
 Reductions in threshold current, i.e.,
minimum current needed for lasing
 Reductions in Pulse Width of Lasers
 Increases in Power of Lasers
 Improvements in cost and power for one
type of laser (GaAs)

For a specific type of laser, e.g., GaAs laser diode
 Improvements are largely driven by creation of new materials
and processes for making those materials
 Heat sink: heat must be removed in order to prevent overheating
of laser
 Mirror: contaminants in mirror cause light to be focused on a
spot and thus burn up the mirror
 Processes
 Fewer defects can have large impact on maximum power because
small reduction in defects can lead to much higher power
 Faster processes leads to lower costs come from faster processing
 Also increases in scale of wafers and associated production
equipment
Source: Martinson R 2007. Industrial markets beckon for high-power diode lasers, Optics, October: 26-27. and
conversations with Dr. Aaron Danner, NUS

Improvements in Average Selling Price (ASP) and
Power of Semiconductor Lasers
Source: Martinson R 2007. Industrial markets beckon for high-power
diode lasers, Optics, October: 26-27.

Applications for Lasers
 Telecom is a big one: covered in Session 10
 But many others
 Information storage (e.g., CDs and DVDs)
 Processing of metals and other materials
 Printing, Surgery
 High power lasers for military, fusion
 Agriculture
 Automated vehicles
 Virtual reality games
 Some of these applications use laser diodes while
other applications use other forms of lasers (gas
and solid state lasers)

Agriculture
 Laser leveled fields facilitate irrigation
 Better control of water
 GPS equipped tractors facilitate harvesting
and seeding
 Remember prescriptive planting in session
4?
 Helps farmers plant seeds with greater
precision using GPS and special seed drills

Cost of Autonomous Vehicles (Google Car) Falls as Improvements
in Lasers and Other “Components” Occur
Source: Wired Magazine, http://www.wired.com/magazine/2012/01/ff_autonomouscars/3/

Better Lasers, Camera chips, MEMS, ICs, GPS Making these Vehicles
Economically Feasible 1 Radar: triggers alert when something
is in blind spot
2 Lane-keeping: Cameras recognize lane
markings by spotting contrast between road
surface and boundary lines
3 LIDAR: Light Detection and Ranging
system depends on 64 lasers, spinning at
upwards of 900 rpm, to generate a 360-
degree view
4 Infrared Camera: camera detects
objects
5 Stereo Vision: two cameras build a
real-time 3-D image of the road ahead
6 GPS/Inertial Measurement: tells us
location on map
7 Wheel Encoder: wheel-mounted
sensors measure wheel velocity
ICs interpret and act on this data

What an Autonomous Vehicle Sees

Underwater Automated Vehicles
 Underwater vehicles for better oil
exploration and fisheries
 More than 50% of consumed fish are from
fish farming
 But fish in fish farms must be fed and this is
costly and the waste damages the local
environment
 Self propelled submersible fish pens can
move fish to food and disperse waste
 Many sensors help make this more
economically feasible

Virtual Reality is becoming economically feasible partly
because lasers are getting better and cheaper. Lasers sense
the head movements so that the field of view changes.

Biological Materials Emit Light!
How it Works
71

Applications
 Lighting
 Can we use trees to provide street
lighting?
 Or to provide indoor lighting?
 In-vivo imaging
 A noninvasive insight into living
organisms
 Understand disease related changes in
the body
 Food industry
 Can help detect pathogens

Challenges
 Very expensive to extract luciferase from fire flies
 Can we make better sources of bioluminescence
through sequencing DNA, adjusting DNA,
synthesizing DNA?
 Discussed in next session
 Can we put DNA into another living organism like has
been done with spider silk?
 Or will the cost of luciferase as we scale up
production?
 Just as cost of chemicals dropped as scale was increased

Conclusions and Relevant Questions for Your
Group Projects (1)
 The luminosity per Watt and their costs continue to be
improved for LEDs and OLEDs because
 Scientists and engineers create new materials that better exploit
the relevant phenomenon
 Also benefits from changes in scale
 How many further improvements are likely to occur?
 When will their costs become low enough or performance
high enough to be economical for specific applications?
 Can we identify those applications, order in which they
will become economical, and specific needs of each
application?

Conclusions and Relevant Questions for Your
Group Projects (2)
 Improvements in lasers continue to occur
 Lower threshold current density
 Higher power
 Shorter pulse widths
 How many further improvements are likely to occur?
 When will their costs become low enough or
performance high enough to be economical for
specific applications?
 Can we identify those applications, order in which
they will become economical, and specific needs of
each application?

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