Developments in LEDs for Lighting

80 Pages·0.467 MB·English

by  Pira International Ltd

Developments in LEDs for Lighting
Alan Mills
Published by
Pira International Ltd
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© Copyright
Pira International Ltd 2006
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Contents
List of tables v Lenses and reflector cups 26
List of figures vi 3
Executive summary vii
1
Outlook for white LEDs 29
Background 29
Introduction 1 Competition 29
Industry structure and overview 1 The qualifier 30
The LED industry and market Drivers 30
development 2 A bright future 31
LED power development 5 4
LED outlook 7
2
LED applications 33
Introduction 33
LED materials and device Display back lighting 33
manufacturing 9 Automotive and vehicle uses 35
LED structures and how they work 9 Introduction 35
Production processes 10 Rear lights 35
Materials used to make LEDs 13 Internal auto lighting 36
Solid materials and wafers 13 Front auto lighting 36
II–VI compound materials 13 Commercial vehicle lighting 37
III–V compound materials 14 Emergency vehicle lighting 38
Ternary gallium nitride materials 15 Camera flash units 38
Aluminium nitride materials 16 General illumination 39
Silicon carbide materials 16 Portable lighting 41
Silicon materials 16 Signage 44
Sapphire materials 16 Introduction 44
Carrier gas material 17 Neon signs 44
Substrate selection 17 Channel letters 45
Homo-epitaxy 17 Safety signs 45
Sapphire substrates 19 Signals 46
Silicon carbide substrates 19 Traffic signals 46
Silicon substrates 20 Rail signals 47
Aluminium nitride substrates 20 Aviation lighting 47
LED colours 20 Marine lighting 48
5
Use of phosphors 21
LED die fabrication, packaging and
encapsulation 24
Die fabrication 24
Packaging and encapsulation 25 Future trends for LEDs 51
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Developments in LEDs for Lighting
Contents
6
Lamina Ceramics, Inc. 59
LED Specialists, Inc. 60
Lumidrives Ltd 60
Lumileds Future Electronics 60
Leading LED suppliers and technical Lynk Labs, Inc. 60
developers 55 Marine Lighting International Ltd 60
Abletech, LLC 55 Maxim Integrated Products 61
ACOL Technologies S.A. 55 Nichia America Corporation 61
AIXTRON AG 55 NuSil Technology 61
AKZO Nobel 55 Nye Lubricants, Inc. 61
American Bright 55 Ocean Optics, Inc. 61
ASM Assembly Automation, Ltd 55 Optical Research Associates 61
AXT Inc. 56 Opto Technology Inc. 62
Bergquist Company 56 Orca Green Marine 62
The Bodine Company 56 OSRAM Opto Semiconductors 62
Candela Instruments 56 Philips Electronics 62
Carclo Technical Plastics 56 Philips Lumileds Lighting Company 62
Cotco International Ltd 56 Power Integrations 63
Cree Inc. 56 Radiant Imaging 63
Curamik Electronics, Inc. 57 Rohm and Haas Electronic Materials 63
Darcy Corporation 57 ROHM Electronics 63
Doran Manufacturing LLC 57 Rubicon Technology Inc. 63
Dow Corning Corporation 57 Saint-Gobain Crystals and Detectors
Epichem Ltd 57 (USA) 63
Evident Technologies, Inc. 57 Savage Marine Ltd 64
Freiberger Compound Materials 57 Sensor Electronic Technology, Inc. 64
Gamma Scientific Inc. 58 Solvay Advanced Polymers 64
GE Advanced Materials 58 Sumitomo Electric Industry 64
Heatron, Inc. 58 SunLion Solar Inc. 64
Hitachi Cable of America 58 Supertex, Inc. 64
Innovations in Optics, Inc. 58 III-Vs Review 65
Innovative Lighting Inc. 58 The LED Shop (online) 65
Instrument Systems 58 Thomas Swan 65
Intematix, Inc. 59 Unipress (Polish Academy of Sciences) 65
Integrated Design Tools Inc. 59 Veeco Instruments Inc. 65
KLA-Tencor 59 Wafer Technology, Ltd 65
Kyocera Corporation 59 Westfleet Direct 66
Labsphere, Inc. 59 Yokohama Electron Co., Ltd 66
Page iv © Copyright Pira International Ltd 2006
List of tables
1.1 Changes in LED light output with 2.1 Compound semiconductor elemental
colour temperature 6 groups 13
Page v © Copyright Pira International Ltd 2006
List of figures
E.1 L ED applications and percentage 2.5 Side and front-emitting LEDs 27
market value, 2006 vii 4.1 LED applications and market value
1.1 Estimated lamp output powers 5 2010 33
2.1 A simple LED 9 4.2 SunLion Solar – Buggy LED
2.2 Quantum well LED on sapphire 10 headlamp 43
2.3 Phosphor-based white LED 21 4.3 OGM masthead navigation light 49
2.4 Intematix QD phosphors 22
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Executive summary
The LED industry Over 70 companies are active in the worldwide LED industry covering the wafer, epitaxy,
chip forming, and packaging supply chains. About 35% of these companies perform
epi-wafer and/or chip manufacture with only about 15% being vertically integrated.
The structure of this industry consists of a mix of captive or integrated and regionally
distributed merchant epitaxy companies with the fraction of merchant epitaxy varying
with the geographic region. The US and Taiwan have about equal volumes of merchant
wafer supply (~40%), with the rest of Asia supplying another 12%. LED packaging is
perhaps unique in this industry, with specialist companies concentrating on packaging
services for the whole industry and making up about 50% of the industry players.
Most Asian LED manufacturers are large well-established companies or their
subsidiaries. Taiwan is an exception to this, with about 25 LED companies with most being
established on a venture basis within the last ten years. Taiwan has a mix of captive and
merchant epitaxy companies, which now claim more than 50% of the world market.
In Europe, most LED manufacturers are associated with large, well-established
international companies such as Philips and Osram, although there are some merchant
suppliers of LED epi-wafers and venture LED manufacturers. In the US, LED suppliers
range from small ventures to larger diversified companies and it is possible anywhere
in the world to have an LED business without a wafer fabrication facility. Sales of LEDs
in 2006 are estimated to be $4.8 billion (€3.78 billion) and the major applications are
shown in Figure E.1.
FIGURE E.1 LED applications and percentage market value, 2006
(cid:53)(cid:83)(cid:66)(cid:71)(cid:71)(cid:74)(cid:68) (cid:51)(cid:70)(cid:85)(cid:66)(cid:74)(cid:77) (cid:48)(cid:85)(cid:73)(cid:70)(cid:83)
(cid:84)(cid:74)(cid:72)(cid:79)(cid:66)(cid:77)(cid:84) (cid:20)(cid:6) (cid:18)(cid:21)(cid:6)
(cid:22)(cid:6)
(cid:34)(cid:86)(cid:85)(cid:80)(cid:16)
(cid:85)(cid:83)(cid:86)(cid:68)(cid:76) (cid:52)(cid:74)(cid:72)(cid:79)(cid:84) (cid:35)(cid:66)(cid:68)(cid:76)(cid:1)(cid:77)(cid:74)(cid:72)(cid:73)(cid:85)(cid:74)(cid:79)(cid:72)
(cid:25)(cid:6) (cid:26)(cid:6) (cid:23)(cid:18)(cid:6)
Source: Pira International Ltd
After LED chip making, LEDs require packaging, which is labour intensive, and is
performed by packaging specialists located in low labour-cost economies such as China,
Malaysia and Thailand. For LEDs to be fully accepted in the general lighting market, many
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Developments in LEDs for Lighting
Executive summary
luminaire types will be required and some venture companies have started to manufacture
LED-based fixtures. Therefore, with the exception of a few young companies, an LED
luminaire industry structure is lacking at this time.
The LED LEDs started as feeble red emitters about 40 years ago; they now provide an extended
range of wavelengths from about 260–400nm. The interest in UV LEDs is driving new and
RGB (red, green and blue) phosphor development for new LED sources.
Prior to the mid-1990s, LEDs provided only red, yellow and limited green wavelengths
without high lumen blue or deep green colours. However, when Nichia Chemical
announced blue LEDs in 1993 and green in 1995, the whole market changed. White light
from the combination of RGB LEDs became feasible and therefore full-colour LED displays
became a commercial reality as blue and green LEDs with higher light outputs were
developed. All the LED markets shown in Figure E.1 benefited from this new technology
and much of their growth to $5 billion since 1995, would not have been possible without
it. This value can be compared to $12 billion for today’s general lighting market, with
little LED penetration at this time. Apart from the existing growth markets, the LED is
just at the beginning of its penetration into the general lighting world of incandescent,
fluorescent and HID lighting.
Hand-held devices The huge hand-held device segment, with typical display sizes in the 1.5–2.5in range, is
commonplace around the world, with two billion units in the field (mobile telephones,
cameras, and personal digital assistants or PDAs). Although telephone flash units are
hand-held appliances, they are not a back lighting use. All these applications are hidden
from the consumer because the LEDs are internal to the equipment used. The estimated
sales for 2006 are $2.8 billion.
Large displays LED backlighting from the larger LCD displays with diagonal measurements in the 15–50in
range, for monitors, laptops and televisions, will eventually form a separate backlighting
segment. Substantial market growth is expected in the future because they will require
many LEDs per display.
The LED using either RGB or blue LEDs with phosphors, can support full-colour
displays and produce good colour rendition without the use of filters. At the same time,
the LED has the added advantage of providing up to 130% of the NTSC specifications.
Benefits of LED backlighting over compact fluorescent systems are that no colour filter is
required, they have thinner and smaller volume lighting systems, higher definition quality
and improved colour rendition. Sony already has a 50in LED model on the market and
has announced an 80in LED prototype only 4cm thick (~2.5in). It uses 1120 RGB Golden
Dragon LED chips in groups of one red (625nm), one blue (458nm) and two green at
527nm. In addition, Osram has demonstrated an 82in TV prototype using its own LEDs.
Current shipments are about 30,000 per year for the large LED-based displays and are
anticipated to grow to 300,000 units in 2008, another LED growth market.
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Developments in LEDs for Lighting
Executive summary
Auto applications In the last ten years, a growing number of automakers have installed interior and exterior
LED lighting, with Europe being the volume leader, followed by the Japanese and Asian
manufacturers. The average number of LEDs per car is now estimated to be over 200,
with well over 50 models being equipped. Vehicle lighting LEDs tend to be low-cost lamps
and therefore have led to single digit or low double digit growth rates, estimated to reach
$380 million in 2006. External LED uses for autos – both front and rear – will allow new
design paradigms, brand identity, adaptive form lighting, youth appeal and new styling
options.
As is often the case with new car technology, LEDs were first introduced in the higher-
priced models, with the first LED units being the red, high-level rear braking light units or
the CHIMSEL (centre high-mounted stop light). All-LED rear lighting units have been used
in high-end cars for some time and included tail, brake, back-up lamps and turn signals.
However, the volume breakthrough occurred last year when two car models, with over
500,000 per year production, were provided with all-LED rear lighting from Volkswagen
and Honda. As other manufacturers follow these leads, continued higher levels of LED
incorporation are assured.
LED lighting, internal to a car, is now widely used by manufacturers and it can
supply glare-free all-around lighting for car interiors and dashboards. It is often being
promoted as a brand recognition item. Some recent auto models allow different colours
to be selected by the driver or passengers and interior LED lighting is now standard for
many models. This growth trend should continue because LEDS offer flexibility, reliability,
reduced power consumption and pleasing design options to the manufacturer and the
customer. It should provide added steady growth to the automotive LED market and may
reach $600 million by 2010.
One of the most anticipated automotive LED applications is that of front lighting,
including running lights, turn signals and headlights. Turn signals and running lights are
now feasible and close to adoption for some high-end models. Prototype headlamp units
have been demonstrated in Europe, Japan and the US, with pre-market concept models
demonstrated by Audi, Cadillac, Ford and Mitsubishi. The number of LEDs required today
for each front lighting function are 6, 10 and 20 for the fog, high-beam and low-beam
functions and these headlamp LEDs may require operating limits of –40 to +105°C or
even higher to qualify. The LEDs will be cool enough to allow acrylic front lenses, but both
active and passive cooling will be needed to meet the anticipated cooling loads. The first
headlamp models still appear to be on time for a high-end model in late 2007 or early
2008 and start adding to the long-term growth of the LED in the auto lighting market.
Commercial and LEDs are now the preferred rear warning and identification lighting method for
fleet vehicles commercial vehicles because of their much longer life, their vibration resistance and
because they are often multi-LED powered, which does not fail catastrophically. They
have much longer useful lives and provide immediate savings over bulb replacement
service work, the largest maintenance cost for vehicle fleets. A selection of tractor-trailer
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Developments in LEDs for Lighting
Executive summary
LED lighting product lines, e.g. red/amber, tail/stop and marker lights, are available
in the $5–20 range. Police car and other emergency vehicles with multicolour warning
requirements benefit from the high power efficiency of blue, red and orange coloured
LEDs and their new low-profile mounting racks. LEDs are already showing good growth in
this market, benefiting their long life and vibration resistance properties and a low cost of
ownership.
Camera flash units The camera flash unit is a relatively new hand-held application for the LED, made
possible as white LED output powers have increased and as pulsed operation has become
a practical consideration. And, the demand for better subject area illumination over a
larger area and for higher pixel counts has also continued to pressure the LED flash unit
manufacturers for both professional camera and phone models. Strong demand from
amateur and professional camera owners for these LED flash units can only improve unit
design and performance and a future need for multiple LED flash units should turn this
segment into another high-volume LED market. The continuing increases in light output
and the ability to overdrive on a pulsed basis make the LED an ideal flash source for
future generations of cameras.
LEDs in general The general illumination market is worth $12 billion and a long sought-after goal of
lighting the LED manufacturers. The largest players are international lighting companies such
as General Electric, Westinghouse, Osram, Sylvania and Philips. The LED is a disruptive
product for this market with DC versus AC, different operating voltages, extended
lifetimes, different light source dimensions and new regulatory compliances. The main
general lighting LED competition is tungsten filament, high-intensity discharge (HID),
fluorescent tube and sodium vapour lamps. Filament or incandescent lamps have the
lowest off-the-shelf cost, the lowest power efficiency, in the 10–15 lumens per watt (lm/W)
range, but their replacements account for about one third of the general lighting market,
or $4 billion. They also have the highest heat output and are relatively short lived. But
for their low initial cost and worldwide supportive infrastructure, they would be easy
prey for the LED. The remaining LED competition has higher initial costs, longer lifetimes
and higher lumen efficiencies in the 35–90lm/W range. The LED still competes in a few
special applications where inaccessible locations, 50,000-hour lifetimes and maintenance
savings weigh heavily in favour of the LED. To protect their market presence, most of the
large players have either started competitive research on the LED or have formed strategic
alliances with LED producers.
LED performance is now up to about 40 lumens for a single LED and 500 lumens for
multi-LED modules (LED arrays are higher). White LED luminaire products based on these
output powers have not yet entered the general lighting market, but will make market
entry within the next two years. Most indium gallium nitride LEDs (blue, green and UV)
are made on sapphire wafers and red, yellow and orange are made on gallium arsenide,
However, Cree Inc., from Raleigh, NC, has added to the complexity by manufacturing high
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