This is a presentation I delivered to several IESNA chapters in fall, 2014.

1. LEDS FOR LIGHTING PROFESSIONALS
Donald G. Hirsh, Sr. Manager, Lighting Experience Center,
don_hirsh@cree.com
November, 2014
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2. N. B.
• Credit(s) earned on completion of this presentation will be reported to AIA
CES for AIA members. Certificates of Completion for both AIA members
and non-AIA members are available upon request.
• This presentation has been registered with AIA CES for continuing
professional education. As such, it does not include content that may be
deemed or construed to be an approval or endorsement by the AIA of any
material of construction or any method or manner of handling, using,
distributing, or dealing in any material or product.
_______________________________________
Questions related to specific materials, methods, and services will be addressed at the
conclusion of this presentation.
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3. Learning Objectives
• At the end of this course, participants will have
information to:
– Compare and contrast modern LED technology with
major categories of evacuated tube technologies.
– Analyze evolving techniques in the design and
development of SSL luminaires.
– Identify recent Advances in LED component
technology.
– Compare categories or types of LED components.
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4. The Agenda – What’s All the Fuss About
• Review of Some General Properties of
LEDs vs. Evacuated Tube Technologies
• LED Typology & Technology
• LED Lighting Futures
– Efficacy and the future of LED Product
Development
– Example: The evolution of the color mixing
technology platforms
• TM-21 & LM-80
• Conclusions: LEDs will rule in the
Medium Term
(What’s In It For Me?)
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5. Creative Destruction: Hard At Work in Your Industry
Vacuum
Tubes Transistors
VHS DVD
CRT Flat Panel
Film
1940s – 1960s
1980s – 1990s
Displays
1990s – 2000s
Flash
Memory
1990s – 2000s
“Brick”
phones
Smart
phones
1990s – 2000s
Use pervasiveness price path to market … all changed
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6. Creative Destruction: Hard At Work in Your Industry
Next up … Lighting
Evacuated
Tubes
Solid State
Lighting
2007 – 2020s
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7. What Is a Light Emitting Diode (LED)?
• Light Emitting Diodes (LEDs) are solid-state
semiconductors that convert electrical energy
directly into visible light.
Packaged LED Chip
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8. White Light from Blue LEDs
Blue + Yellow Phosphor
Blue Peak
Yellow Phosphor
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9. Illumination Source Review
Lighting
Class LEDs
Filament Fluorescent HID
Source Efficacy (lm/w) 130 -200 15-25 80-100 80-130
Optical Control +++++ +++ + +++
Applicability/Adaptability +++++ ++ ++ +++
Lifetime (hrs) 104-5 103 103-4 104
Lumen Depreciation *
Chromatic Stability +++++* +++++ +++ ++
Spectral Profile ++++++ +++++ +++ +++
Thermal Sensitivity ++ ++
Start-Up/Restrike μs ms s m
Dimmable, Controllable Superior Good Possible Not
Toxicity (Hg, Pb, Heavy Metals) + +
Rugged ++++ ++ + +
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10. The Inexorable March of Technology: Efficacy & Packaging
$/lm, normalized
(Cool White, 6500K)
Annual Improvement
in $/lm @ 100 LPW
43% 45% 35% 29% 45% 40% 27%
Efficacy (LPW)
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11. Evolution of Size: Different Die, Same Performance
Gen 1 Gen 2 Gen 3
96% smaller than Gen 1
78% smaller than Gen 2
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12. Example: Flux Groups circa 2008
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13. Flux Groups circa 2014
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14. Contrasting Emission Patterns
Bare HID Lamp Illustration Bare LED Component
Illustration
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15. Small Hemispheres Allow for Precise Optical Control
Bare LED Chip Package
Illustration
Illustration of Altered Distribution
(Secondary Optic Added)
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16. Allows for Dramatically Improved Uniformity
The Prairie School, Racine, WI 2007
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17. Allows for Dramatically Improved Uniformity
LED HPS
141W Total System Wattage 300W
8,040 Average Delivered Lumens 20,520
57 Luminaire Efficacy (Lumens/Watt) 68
1.01fc Maintained Average Footcandles 1.96fc
0.30fc Maintained Minimum Footcandle 0.30fc
53% 2007 Energy Savings -
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18. Seven Years of LED & Systems Innovation
1st Generation
141 Watts
(2007)
Similar illumination performance from recent products
53W
82% Energy Savings
80% Price Reduction vs 2007 Product
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19. So Many Lamps…
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20. So Many LEDs - A Representative Components Portfolio
Discretes Arrays Integrated
Arrays
CXA HD
CXA SD
• One
component
simplifies
design and
assembly
• High efficacy,
high lumen
output
Modules
• High lumen
density for
optical
control
• Excellent
LED-to-LED
color
consistency
• Highest level
of integration
• Speed time
to market
• Excellent
color
consistency
• Design flexibility
• Enables lower system cost
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21. Average Rated Life vs. Average Useful Life
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22. Thermal Management: Radiation vs. Conduction
• LEDs Require Appropriate Thermal Management for Superior Long-Term
Performance
• Thermal Management Drives the Tendency to Integral Luminaire Designs
L70 25,000H L70 100,000H
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23. Comparing Representative Spectral Power Distributions
Daylight Fluorescent
Incan-descent
LED
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24. White CCx, CCy Space
2700K
3000K
3500K
4000K
4500K
5000K
5700K
6350K
7000K
8300K
2450K 2200K
AB2
AB1
AA2
AA1
AB3
AB4
AA3
AA4
AC2
AC1
AD2
AD1
AC3
AC4
AD3
AD4
0.45
0.44
0.43
0.42
0.41
0.40
0.39
0.38
0.37
0.36
0.35
0.34
0.33
0.32
0.31
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0.28
0.27
0.28
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0.31
0.32
0.33
0.34
0.35
0.36
0.37
0.38
0.39
0.40
0.41
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0.44
0.45
0.46
0.47
0.48
0.49
0.50
0.51
0.52
0.53
0.54
0.55
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CCy
CCx

25. LED Production:
Recipes Process  Yield, A Hypothetical Example
2700K
3000K
3500K
4000K
4500K
5B2
5B1
5A2
5A1
5B4
5A3
5A4
5B3
5C2
5C1
5C3
5C4
5D2
5D1
5D3
6B1
6A2
5D4 6A1
6B2
6A3
6A4
6B3
6B4
6C1
6C2
6C3
6C4
6D1
6D2
6D3
6D4
7A1
7A2
7B1
7B2
7A3
7A4
7B3
7B4
7C1
7C2
7C3
7C4
7D1
7D2
7D3
7D4
8A1
8A2
8B1
8A3
8A4
8B2
8B3
8B4
8C1
8C2
8C3
8C4
8D1
8D2
8D3
8D4
0.46
0.45
0.44
0.43
0.42
0.41
0.40
0.39
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0.36
0.35
0.36
0.37
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0.44
0.45
0.46
0.47
0.48
0.49
CCy
CCx
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26. Lighting Applications Matrix
DISCRETES ARRAYS INTEGRATED ARRAYS MODULES
Non-Directional
A & E Bulbs,
Sconces
Directional
MR & PAR, Spot,
Track
Downlight
Ceiling Mount,
Pendant
Linear
Cove, FL Retrofit,
Panel
Outdoor &
High Bay
Roadway, Industrial
Portable
Consumer, High End
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27. Example Lamp and Luminaire Constructions: COB
Matches HID performance with no down sides:
• 50% less power
• 50% less weight
• Lower operating temperature
• 10x longer lifetime
• Instant-on/Instant restrike
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28. LEDs Win vs. CMH Tracklight
3000K, 80CRI
Matches CMH
performance with
no down sides:
• Higher lm/W
• Lower temperature
• No explosion risk
• 10x longer lifetime
• Instant-on
• Instant restrike
Parameter 39W CMH COB COB
System Lumens 2400 lm 3846 lm 4471 lm
System Power 44 W 47 W 53 W
System Efficacy 55 lm/W 82 lm/W 85 lm/W
Beam Angle 15° 16° 16°
CBCP 29,000 cd 25,070 cd 29,150 cd
Parameter 20W CMH Modern COB
System Lumens 1000 lm 1,260 lm
System Power 20 W 15.6 W
System Efficacy 50 lm/W 74 lm/W
Beam Angle 8° 13°
CBCP 13,000 cd 10,943 cd
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29. Increasing Efficacy Leads to Redesigns + Cost Reduction
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30. The Future: Smaller
70W halogen flood performance at 1/4 the size
High Density COB
Prototype Fixture
70W Halogen
PAR38FL
CCT, CRI 3000K, 82 CRI 2900K, 98 CRI
CBCP 2,093 cd 2,379 cd
Beam Angle 40° 40°
Initial Lumens 1010 lm 1381 lm
System Power 14.4W (20%) 74W
Optic 30 mm x 23 mm (~22%) 135 mm x 121 mm
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31. Some Heuristics of LED Phosphor Systems Conversion
Efficiency
• Phosphor Systems Introduce Conversion Efficiencies, which are
(Roughly) Linear and CCT Dependent
– Blue-to-red is least efficient
• Efficacy vs. CCT
– Example: from 5000K 70 CRI to 2700K 80 CRI expect a 20-25%
LPW loss, with roughly linear interpolation.
• (4000K 70 CRI would be ~10% LPW loss)
• Efficacy vs. CRI
– Example: from 2700K CCT, 80 CRI to 2700K CCT, 90 CRI 
20% LPW loss
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32. Example SPDs of a Modern LED Component
Representative SPDs
90 CRI, Outdoor White SPD
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33. DOE LED Roadmap
We’ll get to 250 LPW in production
US DOE MYPP, April 2013, p.47
Consensus:
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34. Uses of a 250LPW LED Source:
1. Trade LPW for cost; save a ton
of money on luminaire first-cost
2. Trade LPW for high CRI
3. Trade LPW for CCT ANY
CCT
4. Enable applications you
thought impossible. Really!
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35. The Evolution of High CRI Lighting Applications
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36. LED Standards Define Many Aspects of Quality
IES TM-21
Lumen
Maintenance
Projections
UL 8750
LED Equipment for
use in Lighting
Products (Safety)
IES LM-80-2008
LED Lumen Maintenance
IES LM-79-2008
SSL Photometry
ANSI C78.377-2008 (Chromaticity)
IES RP-16 SSL Definitions
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37. TM-21 LED Luminous Stability Over Current, Temp, Time
TM-21 Lifetime Report
XLamp XM-L White
LED
I
Data Set 7+ 8+ 9+
Tsp 55°C 85°C 105°C
Sample Size 11 21 14
Test Duration 11,088 hrs 12,096 hrs 8,568 hrs
α 1.182E-06 4.238E-06 6.627E-06
β 1.005E+00 9.999E-01 1.000E+00
Calculated Lifetime L70(11k) = 306,000 hours L70(12k) = 84,100 hours L70(9k) = 53,800 hours
Reported Lifetime L70(11k) > 61,000 hours L70(12k) > 72,600 hours L70(9k) > 47,100 hours
TM-21 Lifetime Report
XLamp XP-G White
LED
I
Data Set 15 16 16
Tsp 55°C 85°C 85°C
Sample Size 25 25 25
Test Duration 8,568 hrs 8,568 hrs 8,568 hrs
α 1.064E-06 2.174E-06 2.174E-06
β 9.913E-01 9.971E-01 9.971E-01
Calculated Lifetime L70(9k) = 327,000 hours L70(9k) = 163,000 hours L70(9k) = 163,000 hours
Reported Lifetime L70(9k) > 51,400 hours L70(9k) > 51,400 hours L70(9k) > 51,400 hours
Reported L70
Calculated Lifetime
Reported Lifetime
2000 mA
110
105
100
95
90
85
80
75
70
65
60
55
50
1,000 10,000 100,000 1,000,000
% Luminous Flux
Time (hours)
55°C (LM-80)
85°C (LM-80)
105°C (LM-80)
55°C (TM-21)
85°C (TM-21)
105°C (TM-21)
Reported L70
Calculated Lifetime
Reported Lifetime
1500 mA
110
105
100
95
90
85
80
75
70
65
60
55
50
1,000 10,000 100,000 1,000,000
% Luminous Flux
Time (hours)
55°C (LM-80)
85°C (LM-80)
85°C (LM-80)
55°C (TM-21)
85°C (TM-21)
85°C (TM-21)
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38. Example High Power LED (LM-80) Data Set
Current Ta (ºC) Tsp (ºC) Tj (ºC)
1500 mA
55 55 75
85 85 105
110
100
90
80
70
60
50
0 2,000 4,000 6,000 8,000 10,000 12,000 14,000
% Luminous Flux
Time (hours)
55°C (LM-80)
85°C (LM-80)
ENERGY STAR 35k
ENERGY STAR 25k
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39. Outstanding Chromatic Stability Over Current, Temp, Time
0.008
0.007
0.006
0.005
0.004
0.003
0.002
0.001
0.000
0 2,000 4,000 6,000 8,000 10,000 12,000
Chromaticity Shift (du'v')
Time (hours)
XLamp XP-G White: If=1.500A, Tsp=85°C
XLamp XP-G White: If=1.500A, Tsp=55°C
XLamp XP-G White: If=1.000A, Tsp=105°C
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40. What Does This Mean? This is Superior Color Stability.
0.008
0.007
0.006
0.005
0.004
0.003
0.002
0.001
0.000
0 2,000 4,000 6,000 8,000 10,000 12,000
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Chromaticity Shift (du'v')
Time (hours)
XLamp XP-G White: If=1.500A, Tsp=85°C
XLamp XP-G White: If=1.500A, Tsp=55°C
XLamp XP-G White: If=1.000A, Tsp=105°C

41. And Now For Something Completely Different
US Dept of Energy, 2013, Color Maintenance of LEDs in Laboratory and Field Applications, PNNL-22759
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42. Recap: LEDs Are Restructuring A Lot of Things
• Applications
• Markets
• Livelihoods
• It’s Early Days
Lighting
Class LEDs
Filament Fluorescent HID
Source Efficacy (lm/W) 130 -200 15-25 80-100 80-130
Optical Control +++++ +++ + +++
Lifetime (hrs) 104-5 103 103-4 104
Lumen Depreciation *
Chromatic Stability +++++* +++++ +++ ++
Dimmable, Controllable Superior Good Possible Not
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43. Finis
Donald G. Hirsh
don_hirsh@cree.com
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