How is Technological Change

Creating New Opportunities in

Lighting and Displays?

8th Session of MT5009

A/Prof Jeffrey Funk

Division of Engineering and Technology

Management

National University of Singapore

Objectives

• What has and is driving improvements in cost and

performance of lighting and display systems?

• Can we use such information to

– identify new types of lighting and display systems?

– analyze potential for improvements in these new

systems?

– compare new and old systems now and in future?

– better understand when new systems might become

technically and economically feasible?

– analyze the opportunities created by these new

systems?

– understand technology change in general

Session Technology

1 Objectives and overview of course

2 Four methods of achieving improvements in performance and cost: 1)

improving efficiency; 2) radical new processes; 3) geometric scaling; 4)

improvements in “key” components (e.g., ICs)

3 Semiconductors, ICs, new forms of transistors, electronic systems

4 Bio-electronics, tissue engineering, and health care

5 MEMS, nano-technology and programmable matter

6 Telecommunications and Internet

7 Human-computer interfaces, virtual and augmented reality

8 Lighting and displays

9 Energy and transportation

10 Solar cells and wind turbines

This is the Eighth Session in MT5009

Outline

• Lighting – Incandescent and fluorescent

– Light emitting diodes (LEDs)

– “System” lighting issues

• Displays – Cathode Ray Tube

– Liquid Crystal Displays (LCDs)

– Cost reductions from increases in scale of LCD substrates

– 3D LCD displays

– Organic light emitting diode (OLED) displays

– Electronic Paper

– Holographic displays

Technology Basic Operation Methods of Improvement

within Technology Paradigm

Electric arc

lights

Passing current across two

electrodes generates heat and light

Materials and gases with high ratio

of luminosity to input power

Electric

discharge tubes

Voltage difference across two electrodes or a filament connecting two

electrodes in a vacuum causes emission of

Incandescent

Lights

visible light (as filament

incandesces)

Filaments with high ratio of

luminosity to input power

Cathode ray

Tube

electrons from one electrode (1)

where electrons striking

phosphors cause photon emission

Cathodes that efficiently produce

electrons and phosphors that better

fluoresce

Fluorescent

Lights

ultraviolet light; these high-energy

photons cause emission of visible

light when they strike phosphors

Gases that efficiently emit

ultraviolet light and phosphors that

better fluoresce

Other lights visible light in gases such as

mercury or sodium vapor

Gases with high ratio of luminosity

to input power

Technology Paradigms for Lighting and Displays (1)

(1) direction of electrodes can be controlled so that electrons hit certain phosphors

Incandescent Lights

• It’s not just their poor

efficiencies (most of

the power is emitted

as heat or non-visible

electro-magnetic

radiation)

• It’s their high costs

– Big connector, bulbs,

filaments

Fluorescent Lighting

• Better efficiencies; e.g., low pressure mercury – emits about 65% in 254 nm

line (visible) and 10–20% of its light in 185 nm line (UV)

– UV light is absorbed by the bulb's fluorescent coating (phosphors), which re-radiates the energy at longer “visible” wavelengths

– blend of phosphors controls the color of light

• But still high costs – Bulb

– Connector

– gases

Outline

• Lighting – Incandescent and fluorescent

– Light emitting diodes (LEDs)

– “System” lighting issues

• Displays – Cathode Ray Tube

– Liquid Crystal Displays (LCDs)

– Cost reductions from increases in scale of LCD substrates

– 3D LCD displays

– Organic light emitting diode (OLED) displays

– Electronic Paper

– Holographic displays

Technology Basic Operation Basic Methods of Improvement

within Technology Paradigm

Light emitting

diodes (LEDs)

Semiconductor diode emits light

when voltage is applied

Semiconductors with high ratio of

luminosity to input for LEDs and

also high coherence for lasers.

Reducing size can reduce cost. Semiconductor

laser

Semiconductor diode emits light

“coherent” in single wavelength

when voltage is applied

Semiconductor laser is basically

an LED with a waveguide and a

mirror

Technology Paradigms for Lighting and Displays (2)

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 Different Colors

Semiconductor Lasers are LEDs with a Waveguide and Mirror

Laser types shown above the wavelength bar emit light with a specific

wavelength while ones below the bar can emit in a wavelength range. Non-

semiconductor lasers are also shown in this figure

Luminosity per Watt (lm/W) for Various Lighting Technologies

Source: Jeffrey Tsao (Sandia) and Aaron Danner (NUS)

Source: NTT develops current-injection photonic-crystal laser

http://www.physorg.com/news/2012-02-ntt-current-injection-photonic-crystal-laser.html

Average Selling Price (ASP) and Continuous Wave

(CW) Power of Semiconductor Lasers have risen

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

Surface Mount LED

• Printed Circuit Board based

• Advantages

Size, thickness

SMT process, more popular

• Disadvantage

Less immunity to environmental

No optic design, customized

viewing angle

Complicated process

Both reductions and increases in scale drive Cost Reductions

Increases in wafer and equipment size also drive reductions in cost

PicoLED: The World Smallest LED

Introduced by ROHM Semiconductor, Japan, in year 2007, with the

footprint of 1.0x0.6x0.2 mm

Are there Limits?

• What are the limits to improvements in

efficiencies with existing and new technologies?

– The maximum theoretical efficiencies for LEDs are

much higher than current efficiencies

– This suggests that there are still opportunities for

improvements

– How about costs? Can they be further reduced?

• Are their limits to miniaturizing the size of lights

(and displays)? How small can lights be made

(and how thin can displays be made)?

• Will LEDs create a new paradigm for lighting by

providing intelligent directional light?

Warm white

Cool white

Daylight white

But initial cost of

solid state lighting

is higher!

What about Organic LEDs (OLEDs)

OLEDs

• Will these improvements in luminosity per

Watt continue?

• How about costs?

– Organic materials can be roll printed onto a

substrate, making them potentially cheaper

than that of LEDs, which require high

temperature processing

• What might be the initial applications for

them?

Outline

• Lighting – Incandescent and fluorescent

– Light emitting diodes (LEDs)

– “System” lighting issues

• Displays – Cathode Ray Tube

– Liquid Crystal Displays (LCDs)

– Cost reductions from increases in scale of LCD substrates

– 3D LCD displays

– Organic light emitting diode (OLED) displays

– Electronic Paper

– Holographic displays

We are trying to use the same connectors for LEDs and

incandescent bulbs.

How about creating a new interface standard that is

cheaper and better? (think of your computers and phones)

Furthermore

• How about using the electronic nature of

LEDs to devise intelligent lighting systems

– Lights that can be directed to specific

locations

– Turn off when no one is near the light or

looking at the specific location

• ICs get cheaper and more intelligent every

year

Outline

• Lighting – Incandescent and fluorescent

– Light emitting diodes (LEDs)

– “System” lighting issues

• Displays – Cathode Ray Tube

– Liquid Crystal Displays (LCDs)

– Cost reductions from increases in scale of LCD substrates

– 3D LCD displays

– Organic light emitting diode (OLED) displays

– Electronic Paper

– Holographic displays

Technology Basic Operation Methods of Improvement

within Technology Paradigm

Electric arc

lights

Passing current across two

electrodes generates heat and light

Materials and gases with high ratio

of luminosity to input power

Electric

discharge tubes

Voltage difference across two electrodes or a filament connecting two

electrodes in a vacuum causes emission of

Incandescent

Lights

visible light (as filament

incandesces)

Filaments with high ratio of

luminosity to input power

Cathode ray

Tube

electrons from one electrode (1)

where electrons striking

phosphors cause photon emission

Cathodes that efficiently produce

electrons and phosphors that better

fluoresce

Fluorescent

Lights

ultraviolet light; these high-energy

photons cause emission of visible

light when they strike phosphors

Gases that efficiently emit

ultraviolet light and phosphors that

better fluoresce

Other lights visible light in gases such as

mercury or sodium vapor

Gases with high ratio of luminosity

to input power

Technology Paradigms for Lighting and Displays (1)

(1) direction of electrodes can be controlled so that electrons hit certain phosphors

Technology Basic Operation Basic Methods of Improvement

within Technology Paradigm

Liquid crystal

display (LCD)

Alignment of crystals modulates an external light source (e.g., a

backlight) where alignment of crystals depends on input voltage

Passive output of pixel depends on

voltage applied to row and

column via multiplexing

Increase resolution with more

pixels where improvements

limited by need to multiplex

Active output of pixel depends on

voltage applied to each

pixel, i.e., transistor

Increases in transistor density

improve resolution, viewing angle;

thinner materials lead to lower cost

Organic light

emitting diode

(OLED)

Organic materials emit light

depending on input voltage and

band-gap of material

Materials that have high ratio of

luminosity to input power. Use of

thinner layers reduce costs

Technology Paradigms for Lighting and Displays (2)

Limits to Miniaturization (e.g., thinner)*

(current ranking)

As Lights As Displays

Electric

discharge tubes

Cathode ray tubes

LEDs Liquid Crystal Displays (with cold

cathode fluorescent backlight)

Liquid Crystal Displays (with LED

backlight)

Organic Light Emitting Diode

OLED: emit their own light, so now

backlighting is needed

*Remember that costs typically fall over the long term as size is reduced

Gre

ater

pote

nti

al f

or

mak

ing

s

mal

ler

and t

hin

ner

Major components of LCD TV

CCFL Backlit LCD TV CCFL Backlight Diffusers To ensure a uniform brightness across panel

Polarizer To ensure that the image produced is aligned correctly

LCD Panel An LCD panel is made up of millions of pixels filled with liquid crystals arranged in grid, which open and shut to let the backlight through and create images

Antiglare Coating Provides a mirror-like finish, making the backlight appear brighter

Display Screen

Current

challenge

for LCD TVs:

Replace this

layer (cold

cathode

fluorescent

light)

(78.6 mm)

with white-

light LEDs

(29.9 mm)

How to achieve White Color LED

RGB White LED

• Mixture of Red, Green & Blue

color to get white color LED.

• Involved electro-optical design to

control blending & diffusion of

different colors

Phosphor Based White LED

• 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.

LED Die

Phosphor

Phosphor Based White LED Spectrum of Phosphor LED RGB Color Chart

Outline

• Lighting – Incandescent and fluorescent

– Light emitting diodes (LEDs)

– “System” lighting issues

• Displays – Cathode Ray Tube

– Liquid Crystal Displays (LCDs)

– Cost reductions from increases in scale of LCD substrates

– 3D LCD displays

– Organic light emitting diode (OLED) displays

– Electronic Paper

– Holographic displays

Increases in Scale of IC Wafers, LCD

Substrates, Solar Substrates (1)

• Equipment costs per area of output fall as size of equipment is increased, similar to chemical plants – Cost is function of surface area (or radius squared)

– Output is function of volume (radius cubed)

– Thus, costs increase by 2/3 for each doubling of equipment capacity

• For IC Wafers, LCD Substrates, Solar Substrates – Processing, transfer time (inverse of output) fall as

volume of gas, liquid, and reaction chambers become larger; costs rise as function of equipment’s surface area

– partly because larger scale enables higher temperature and pressure

Increases in Scale of IC Wafers, LCD

Substrates, Solar Substrates (2)

• Wafer size for ICs has steadily risen over the last 50 years

– Now at 12”

– Expected move to 18” in next few years

• Techniques for miniaturizing patterns on IC wafers have

required firms to also reduce the thickness of materials that

are deposited (and later patterned) on wafers and

LCD/Solar substrates

• The result is costs per transistor, capital costs per

transistor, and even costs per area of a silicon wafer and

LCD and solar cell substrate have fallen over the last 50

years even as the cost of fabrication facilities has increased

Another Benefit from Large Panels is Smaller Edge Effects

Panel

Equipment

Effect Effects: the equipment must be much

wider than panel to achieve uniformity

Ratio of equipment to panel width falls as the

size of the panel is increased

Increases in LCD Substrate Size

Source: www.lcd-tv-reviews.com/pages/fabricating_tft_lcd.php

Scale of photographic aligners (upper left),

sputtering equipment (top right), and

mirrors for aligners (lower left) for LCD

equipment

Source: http://www.canon.com/technology/

canon_tech/explanation/fpd.html

Cost Reductions for Semiconductors, LCDs, and Solar Cells

Technology Dimension Time Frame Ratio of New to

Old Cost

Semiconductors/

ICs

Price/

Transistor

1970-2005 1/15,000,000

Price/Area 1970-2005 1/20

Price/Area 1995-2005 1/5.7

LCDs Price/Area 1995-2005 1/20

Solar cells Price/Watt 1957-2003 1/500

Price/Watt 1975-2001 1/45.4

Price/area 1970-2001 1/37.0

Price/area 1995-2001 1/3.42

Sources: (Gay, 2008; ICKnowledge, 2009; Kurzweil, 2005; Nemet, 2006), author‟s analysis

• Nishimura’s Law: – The size of LCD substrate grows by a factor of 1.8 every

3 years, doubles every 3.6 years (large panels are cut into appropriate sizes for electronic products)

– Less than half the time for IC wafers to double in size (7.5 years)

• Odawara’s Law: – Costs fall by 22-23% for doubling in cumulative

production

• Kichihara’s Law: every three years – Power consumption decreases by 44%

– Panel thickness and weight are reduced by one-third

– Number of bits needed per screen increases fourfold

Display Panel Trends – towards larger and

cheaper panels

Source: http://metaverseroadmap.org/inputs.html, US Display Consortium (USDC)

• We can also see the falling cost of LCDs

in the falling price of LCD TVs, albeit some

of the cost reductions are coming from the

falling costs of ICs

Source: Bing Zhang, Display Search, Flat Panel TV Cost

Analysis & Panel Supply-Demand , May 20, 2008

6

5

4

3

2

1

0 01 02 03 04 05 06 07 08 09 10 11

Prices and Costs of LCD Panels per Square Meter

(Thousands of US$)

Average selling price

Production costs

Source: Television Making: Cracking Up, Economist, January 21st, 2012, p. 66

Outline

• Lighting – Incandescent and fluorescent

– Light emitting diodes (LEDs)

– “System” lighting issues

• Displays – Cathode Ray Tube

– Liquid Crystal Displays (LCDs)

– Cost reductions from increases in scale of LCD substrates

– 3D LCD displays

– Organic light emitting diode (OLED) displays

– Electronic Paper

– Holographic displays

Time-Sequential 3D with active 3D Glasses

Sources for

these slides:

Adapted from

presentation by

Ng Pei Sin

Improvements in Frame-Rate are Occurring

0

50

100

150

200

250

300

1970s 1995 2008 2010

CRT

LCD

OLED/Plasma

• Increased frame-rate of content approaches Critical Flicker Fusion point (where higher

frame rate has no perceived benefit) – 60Hz.

– Increase frame rate gives smoother, flicker-free motion, especially in high-action videos

• Increased Frame-rate of Display

– Reaches 120Hz; surpasses critical flicker fusion point

• Surplus enables implementation of Time-sequential 3D without compromising improved

frame rate of content

• Improved LCD frame-rate due to improvement in Liquid Crystal structure, reduced cell-

gap, and improved methods to shorten liquid crystal response time

120Hz - Minimum screen frame-rate

for „flicker-free‟ Time-sequential 3D

Fram

e p

er s

eco

nd

s (H

z)

Display Frame-Rate

Improvements in Frame Rate Increase the

Economic Feasibility of Time Sequential 3D

• Improvement in Liquid Crystal

response time enable:

– High frame-rate in LCD display

and in active 3D glasses

• Economical

– Estimated cost of adding 3D to

LCD display range from 10% to

30% the cost of panel

– Falling costs from larger substrate

size can offset these higher costs

• But glasses are a big

disadvantage……….

Auto-Stereoscopic Displays

Does not require special 3D glasses

Panel pixels are divided into two groups one for left-eye images

another for right-eye images

A filter element is used to focus each pixel into a viewing zone

In order to view television from different places in the room, multiple viewing zones are needed

• Improvements in photolithographic equipment enable

increases in pixel density

– lags resolution in ICs by many years

• Sometimes called Kitahara’s Law, improvements of

about 4 times occur every 3 years

• These increases in pixel density

– Enable high definition television

– But will exceed the resolution of our eyes

• Thus, these increases can be used to assign different

pixels

– to right and left eye and

– to different “viewing” zones

Increases in Pixel Density, i.e., Resolution

• At least128 million pixels/sq inch are

needed

– 8.3 million pixels needed for high-definition TV

– at least eight viewing zones needed to

accommodate head movements

– each viewing zone needs two sets of pixels

– 8.3 x 8 x 2 = 128

• Best pixel density at Consumer Electronics

Show in 2011 was 8.3 million pixels/sq inch

– If pixel density continues to increase four-times

every three years, technical feasibility in 2017

– As for economic feasibility, this depends on

incremental cost of the higher densities. If the

incremental cost is small, they will probably

become economically feasible before 2020.

Auto-Stereoscopic Displays

• Standardization and digitalization ease handling, storing and presentation of 3D videos

• Standardization reduces complexity and cost of having to produce 3D contents for multiple competing formats

• Digital 3D formats build from MPEG-4 video compression with Multiview Video Coding (MVC) encoding

“Historical Progression of Media”, From: Three-Dimensional Television: Capture,

transmission, Display. By Haldun M. Ozaktas, Levent Onural

Other Factors Driving Economic Feasibility:

Standardization and Digitization of Video

Other Factors Driving Economic

Feasibility: Better graphic processors

http://www.behardware.com/articles/659-1/nvidia-cuda-preview.html

“NVIDIA® TESLA® GPU COMPUTING”, Nvidia, 2010, http://www.nvidia.com/docs/IO/43395/tesla-brochure-12-lr.pdf

Improved Graphics processing unit (GPU) enables:

More MPEG4 video compression

Rendering of more realistic computer animation (more

polygon count and motion control points)

Rendering of 3D models for stereoscopic video for 3D

displays

Enable realistic stereoscopic computer animation

good enough for cinema screens presentation,

increasing contents in 3D

Outline

• Lighting – Incandescent and fluorescent

– Light emitting diodes (LEDs)

– “System” lighting issues

• Displays – Cathode Ray Tube

– Liquid Crystal Displays (LCDs)

– Cost reductions from increases in scale of LCD substrates

– 3D LCD displays

– Organic light emitting diode (OLED) displays

– Electronic Paper

– Holographic displays

Another Option is an OLED

• OLED: Organic Light Emitting

Diode

• Made of organic (Carbon based)

materials that emit light when

electricity runs through them

• They can be roll printed onto a

substrate, making them potentially

cheaper than that of LCDs

• Construction of OLED

– Substrate

– Anode

– Conductive layer

– Emissive layer

– Cathode

OLEDs also have fewer Layers than LCDs and

thus potentially less expensive

LCD

• Complex structure

• Passes through light and thus

requires separate light source

and color filters

LED

• Simple structure

• Source of light

Performance of LEDs and OLEDs Over Times

One Problem with OLEDs is their Lifespan

• Average life span of about 30,000

hours of viewing, half of LCD TVs

60,000 hours.

• The blue OLEDs degrades

significantly as compared to other

colors – bringing color balance

issues.

• Thus OLED displays must be given

a blue tint to offset the subsequent

degradation in blue color

•Can these problems be solved?

• Do OLEDs have a future in some

applications?

Data on hours

Outline

• Lighting – Incandescent and fluorescent

– Light emitting diodes (LEDs)

– “System” lighting issues

• Displays – Cathode Ray Tube

– Liquid Crystal Displays (LCDs)

– Cost reductions from increases in scale of LCD substrates

– 3D LCD displays

– Organic light emitting diode (OLED) displays

– Electronic Paper

– Holographic displays

Outline

• Lighting – Incandescent and fluorescent

– Light emitting diodes (LEDs)

– “System” lighting issues

• Displays – Cathode Ray Tube

– Liquid Crystal Displays (LCDs)

– Cost reductions from increases in scale of LCD substrates

– 3D LCD displays

– Organic light emitting diode (OLED) displays

– Electronic Paper

– Holographic displays

Holographic Systems

• Present a real 3D image

• LCD-based 3D systems present an “illusion” of

three dimensions

– Time-Sequential 3D with active 3D Glasses

– Auto-Stereoscopic Displays

• Holographic Systems present a real 3D image

and thus one that is more aesthetically appealing

• When might such a system become

technically and economically feasible for

some application and some set of users?

Conclusions (1)

• New types of lighting & displays continue to emerge

– Lighting: LEDs, OLEDs

– Displays: 3D LCDs, OLEDs, Holographic systems

• These changes have and continue to create new

opportunities in the new technologies and those

that support them

Conclusions (2)

• The rate of improvements in the performance and

cost of these systems suggests that

– LED-based lighting are just a few years away

– OLED displays are also just a few years away

– One type of 3D display (with glasses) is becoming

economically feasible and a second one (without

glasses) will probably become economically feasible in

the next ten years

– Holographic systems are probably at least 10 years away

Relevant Questions for Your Projects

• To what extent will improvements in ICs,

displays, and other component technologies

continue to occur?

• To what extent will these improvements enable

new forms of lighting and displays?

• To what extent will this create entrepreneurial

opportunities and what kinds of opportunities?