Cree Gen Ltg Training

What is light ?
Spectrum of Electromagnetic Radiation H

Cosmic Gamma X-rays UV Infrared Radar FM AM
rays rays radio radio

10-16 10-12 10-8 10-4 0 104 108 (m)

Visible Spectrum

380 (nm) 780 (nm)

Copyright © 2008, Cree, Inc. Cree Proprietary - CONFIDENTIAL pg. 2

What is a lamp ?

A LAMP (light source) is an emitter of electromagnetic radiation in
the visible part of the energy spectrum.


Radiometry & Photometry H

• Radiometric light is specified according to its
radiant energy and power without regard for the
visual effects of radiation.

• Photometric light is specified as radiation in
terms of human visible response according to the
CIE standard observer response curve (photopic
luminous efficiency function)


Terms of the industry H

Luminous Flux
Eye sensitivity
Illuminance
Luminous Intensity
Luminance
Color


Luminous Flux H

The amount of light radiated
by a light source.

Unit: lumen (lm -
photometric)
Watts (W - radiometric)


Eye Sensitivity H

1,0
relative eye sensitivity

0,8

0,6 V( )

0,4

555 nm
0,2

0
400 500 600 700 800
wavelength (nm)
1 W555nm = 683 lm


Illuminance
Definition of illuminance

The amount of light falling
on a unit of surface.

E
Unit: lux (lx=lm/m2)
W/m2


Illuminance

Typical illuminance levels in and outdoors (noon on a sunny day).

100 lux 2500 lux 5000 lux 10 000 lux 100 000 lux


Luminous Intensity

Definition of Luminous Intensity (unit: candela (lm/sr,cd), W/sr)
The amount of light radiated
by a light source in a given direction.

1 candela = 1 lumen per steradian


Luminance (Brightness)
Definition of Luminance (unit: candela per m2 (cd/m2))

Luminance: The amount of light radiated by a unit
of apparent surface in a given direction.

At same luminous flux:
same luminous intensity but different luminance (brightness)


Color Impression of the Light H

The color impression of light
is characterised by:

•Color temperature (Tc)
•Color rendition (Ri)


Color of the Light
Color Temperature

Tc = 5500K Tc = 2200K


(Correlated) Color Temperature

• Incandescent
(temperature of the
filament)
• Gas discharge
(correlated color
temperature)


Luminous Flux and Color of the Light
CIE Chromaticity Diagram: Black Body Line

0.5 580
3000K
y
5000K

0.4 7000K A
600
10 000K
D65
2000K
20 000K
0.3
770

0.2

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
x


Color Rendition

• Object spectral reflectance
• Light source color distribution
• Adaptation of the eye


Color Rendition

Sunlight Has a CRI of 100. When Low Pressure Sodium has a CRI less
objects are illuminated with sunlight, all than 0. Objects illuminated by it all
the colors look good. look brown.


Color Rendition

1 2 3 4 1 2 3 4

5 6 7 8 5 6 7 8

9 10 11
9 10 11

12 13 14
12 13 14
Test Colors Illuminated by a source with Test Colors Illuminated by a red LED
a CRI of 100, i.e. an incandescent lamp.


Color Rendering Index (Ra)

• Ra = 90 - 100
Excellent color rendering properties
• Ra = 80 - 90
Good color rendering properties
• Ra = 60 - 80
Moderate color rendering properties
• Ra < 60
Poor color rendering properties


White LEDs

• RGB Mixing

By mixing Red, Green
and Blue sources any
color light, including
White, can be made.


How a Phosphor LED Works

The phosphor emits a yellow photon. This
process is called fluorescence.

If the phosphor is thin, some blue photons get
through without being absorbed.

Different phosphors emit different colors: blue, green, yellow, orange, red. The color
of the fluorescence photon is always at a longer wavelength than the incident photon.


White LEDs

• Phosphor Conversion
Approach Blue + yellow appears white.

Blue emission is converted
to yellow by the phosphor
coating over the chip and
reflector cup. The mixture
of blue and yellow light
appears white. Yellow phosphor
coating Blue LED chip
on chip and
reflector cup


Lamp Performance Terms

• Efficacy
• Lamp Life and Lumen Depreciation


Lamp Efficacy
Improvement

lm/W
200
Low-pressure Sodium

150
High-pressure Sodium

Metal Halide
100
Fluorescent Compact Fluorescent

High-pressure Mercury
50

Halogen

Incandescent
0
1940 1950 1960 1970 1980 1990 2000

Luminous flux (lm)
Efficacy (lm/W) =————————
Power Input (W)


Lamp Life and Lumen Depreciation

100
90
%

80
Lumen depreciation of /Colour 80 series lamps
70

60

50
0 5000 10 000 15 000 20 000
operating hours
100
survivals in %

90

80

70
Rated average lamp life (‘TL’D on HF gear)
60

50
0 5000 10 000 15 000 20 000
operating hours

Lamp Life and Lumen Depreciation

Average Rated Life
• ‘The time after which 50% of a large sample
batch have failed when operated under test
conditions.’

Service Life
• ‘Takes into account lumen maintenance curves
and lamp survival curves’


Dimensions of Lamps and Light Emitting Area

Accent lighting Localised lighting General lighting
“Compact” Linear systems
“Small” Spots “Power” Spots “Floods”
Downlighting & tiles
Narrow beam Medium beam
Wide beam / Directional Diffuse
accents accents

Point Compact Linear
source source source

size
Smaller lamp gives luminaire size reduction
or improved optical performance

Control Gear

Discharge lamps must be used with control gear
to:

1. limit lamp current
2. create ignition peak
3. power-factor correction

Gear may be electronic or conventional


Effect of UV
Permitted Exposure Time

PET* is the Permitted Exposure Lamp type PET*
Time a human being can spend (hr x klux)
beneath a given source at 1000
lux illumination without TL /840 65
experiencing eye or skin
CDM-T /830 24
irritation/damage.
SDW-T 34

Damage Factor
Dfc, Damage Factor, is a relative Lamp type Dfc
ranking of light sources related to
their potential for causing a fading
of illuminated objects. The factor is TL /840 .21
calculated using equal conditions
of illumination and exposure time, CDM-T /830 .20
and the sensitivity characteristics
of paper. SDW-T .10

Cree Proprietary - CONFIDENTIAL

Improved Ecological Balance

1. Efficacy improved

2. Miniaturization:
less material in
products and
packaging reduced

3. Less hazardous
materials


Lamps - Performance/Cost Balance

Performance: Costs:
Image & Comfort Cost of Ownership
Flux Efficacy
Size Life
Color Quality Maintenance


Light Generation
Incandescence LED Gas Discharge

Tungsten Tungsten Sodium Mercury
Halogen
Low Pressure Sodium Low Pressure Mercury
‘SOX’ ‘Fluorescent’

High Pressure Sodium High Pressure Mercury
‘SON’ ‘HPL’

Metal Halide Lamps


Incandescent Lamps
Lamp Characteristics

Luminous flux 120 - 18 800 lm
Luminous efficacy < 19 lm/W
Color temperature 2700 K
Color rendering Ra 100

Lamp power 15 - 1000 W
Rated average lifetime 1000 hrs

Issues
• Dimming is possible
• Voltage fluctuations do influence luminous flux,
power consumption and rated average lifetime
• Lumen depreciation during lamp lifetime because
of evaporating tungsten (lamp blackening)
• Instant start and restart
• Cheap


Tungsten Halogen Lamps
Working Principle

Halogen Cycle >250°C

tungsten
WBr2 halide
molecules

1000°C
bulb wall 2Br
formation
dissociation
W

W + 2 Br WBr2


Tungsten Halogen Lamps

Color temperature 2900 / 3200 K

Rated average lifetime 2000 - 5000 hrs

Issues
• Dimming is possible
• No lamp blackening during lamp life
• Voltage fluctuations do influence
luminous flux, power consumption and rated average
lifetime
• Low voltage halogen lamps require a transformer
• Halogen lamps without double envelope should not be
touched with bare fingers

Low-Pressure Sodium Lamps
Lamp Construction

bend insulation cap dimple filled with sodium
discharge tube electrode
outer bulb getter
lamp cap

_ +
cathode _ + anode
_ +
_ +
electrons
positive ions


Low-Pressure Sodium Lamps

Color temperature 1700 K
Light color monochromatic yellow
Color rendering Ra not applicable

Rated average lifetime 18 000 hrs

Issues
• Control gear required
• Run-up time of 12 minutes approx
• Re-ignition time of 1-10 minutes
• Most efficient light source, but with worst light
quality


High-Pressure Sodium Lamps
Lamp Construction

support wire
„Hg free‟ discharge tube lamp cap
indication getter of sintered alumina

outer bulb

electrode PIA
Philips Integrated Antenna


High-Pressure Sodium Lamps

Color temperature 2000, 2200, 2500 K
Light color orange, warm white
Color rendering Ra 25 - 80

Rated average lifetime 10 000 - 24 000 hrs

Issues
• Run-up time of 3 - 6 minutes
• Re-ignition within 30 seconds - 4 min.
• Most efficient light source with acceptable light quality
for most functional outdoor lighting applications


Fluorescent Lamps
Lamp Construction

ultraviolet
glass tube light radiation cap

fluorescent mercury electrons electrode
powder atom


Fluorescent Lamps

Luminous flux 200 - 5200 lm
Color temperature 2700 - 6500 K
Color rendering Ra >80, >90, 60
(depending on composition of
fluorescent powders)

Lamp power 4 - 58 W
Rated average lifetime 14 000 hrs (conv.)
20 000 hrs (electr.)
15 000 hrs (PLE-T)

Issues
• 80/ Series recycling
• Trend to lower mercury doses
• Fully dimmable (4 pin)
• Not instant start without special circuitry - usually 2.5s min “off”
• Starting, warm-up, flux and even CCT are temperature
dependent, usually 1-5 min for 80% flux.


Fluorescent Lamps
Issues

3 different groups of fluorescent powders Increasing
• Standard fluorescent lamps Price
– moderate luminous efficacy
– moderate color rendering (Ra: 50 - 75)
– moderate lumen depreciation
• 3-line fluorescent lamps
– very good colour rendering (Ra > 80)
– very low lumen depreciation
• de-Luxe fluorescent lamps
– moderate luminous efficacy
– excellent color rendering (Ra > 90)
– low lumen depreciation


Fluorescent Lamps
Issues

Lumen Maintenance
100
lumen in %

Super /80
90

/90 de Luxe
80

70
Standard
60

50
0 5000 10 000 15 000 20 000
operating hours


The Range of Fluorescent Lamps

T12

TLD

TL5

PL-L

PL-S / PL-C / PL-T

PLE-C / PLE-T


QL Fluorescent Lamps


Induction Fluorescent Lamps
Lamp Construction

Fluorescent powder

Mercury Antenna

Coil

Glass bulb

Auxiliary amalgam
Heat conducting rod

Coaxial cable Main amalgam
Lamp cap
Mounting flange


Induction Fluorescent Lamps

Light color (inc.) warm & neutral white

Lamp power 55, 85, 165 W
Lifetime* 60 000 hrs
* 10% lamp failure, 30 % lumen depreciation

Issues
• Run on electronic gear only
• Luminous flux is independent of fluctuating supply voltage
• Fast run-up and instant re-ignition
• Not dimmable
• Limited distance between lamp and HF-generator


High-Pressure Mercury Lamps
Lamp Construction

fluorescent powder
discharge tube support
discharge tube (quartz)
outer bulb

main electrode
auxiliary electrode
resistor

stem

lamp cap


High-Pressure Mercury Lamps

Color temperature 3400, 4000 K
Light color neutral white
Color rendering Ra 40, 55


Issues
• Control gear required (ballast only)
• Re-ignition within 5-10 minutes
• Useful lifetime is reached when
lamp color shifts to green


Metal Halide Lamps
Lamp Construction

getter
discharge tube support stem
discharge tube (quartz) lamp cap

electrode
outer bulb


Metal Halide Lamps

Color rendering Ra 65 - 92

Rated average lifetime 4000 - 20 000 hrs

Issues
• Control gear required.
• Quartz metal halide technology cannot totally avoid visible
light color differences between individual lamps.
• Useful lifetime: light color shifts to greenish/blueish color
appearance.
• Run-up time of 3 - 5 minutes
• Re-ignition time of 15 - 20 minutes
• Pay attention to limited burning positions!

Ceramic Discharge Metal Halide Lamps
Lamp Construction

quartz glass bulb
getter
PCA* discharge tube
electrode
sealing glass

support wire

lamp cap

* Poly Crystaline Alumina


Color Stability



Color temperature 3000, 4200 K
Light color warm, neutral white
Color rendering Ra > 80, 90

Lamp power 35, 70, 150 W

Issues
• Stable color impression during lifetime
• Hardly any spread in color characteristics between individual lamps
• Re-ignition time of 15 minutes approx
• Luminaires for CDM-TP and -R do not need front cover, but all others do.


Relative Lamp Sizes
„TL‟D

„TL‟5

SOX

MHD

HPI Plus SON HPL-N QL CFL-I SDW-T CDM-R GLS Masterline LED
Plus


Lamp Survey

Incand. Tungsten Linear Non Retrofit QL SOX SON SDW-T HPL HPI MHN/ CDM ML
fluoresc. retrofit CFL MHD
CFL
Power 15 - 5 - 2000 4 - 58 5 - 55 5 - 23 55 - 165 18 - 180 50 - 1000 35 - 100 50 - 250 - 70 - 35 - 150 100 –
[W] 1000 1000 2000 2000 500
Luminous flux 120 - 60 - 200 - 250 - 200 - 3500 - 1800 - 3500 – 1300 - 1770 - 19 000 - 5300 - 3300 - 1100 -
[lm] 18 800 48 800 5200 4800 1500 12 000 32 500 90 000 5000 58 500 189 000 220 000 14 000 13 000
Luminous
efficacy < 19 < 27 < 104 < 87 < 65 < 70 < 203 < 150 < 52 < 61 < 94 < 110 < 95 < 26
[lm/W]
Light colour warm warm warm, warm, warm warm, yellow orangeish warm neutral neutral warm, warm, neutral
white white neutral, neutral, white neutral monoch white white white neutral, neutral white
daylight daylight white romatic dalight white
white white white
Colour temp. 2800 3000, 2700 - 2700 - 2700 3000, 1700 2000, 2200 2500 3300 - 4300 3000 - 3000, 3300 -
[K] 3200 6500 6500 4000 4200 5600 4200 3700
Ra 100 100 > 80, > > 80 > 80 > 80 n.a. 25, 65, > 80 45 , 55 69 75 - 90 > 80, 48 - 72
90, 60 > 90
Rat. aver. 1000 2000 - 13 000 - 8 000 - 6000 - 100 000 18 000 10 000 16 000 <20 000 2000 - 6000 - 10 000
Lifetime [hrs] 5000 20 000 16 000 12 000 9000 12 000
Ballast no no yes yes no HF Yes yes yes yes yes yes yes no
generator
Ignitor no no yes yes no no yes yes yes no yes yes yes no
Run-up time zero zero zero zero <1 zero 12 4-6 3 5 3 3-5 3 5 - 10
[min]
Re-ignition zero zero zero zero zero zero 1 - 10 30 sec. - 4 30 sec 10 15 15 - 20 15 5
time [min] min.


TH TL CFL SON CDM MH GLS QL

Lighting for the Home

CRI 85-100
CCT 2700K
Lumens 400-1200lm
Source size Point
Benchmark GLS



Accent lighting for Shops

CRI 85
CCT 3000K
Lumens 1000-14000lm
Source size Point
Benchmark CDM/TH



Lighting for Roads

CRI 20
CCT 2000K
Lumens 30K-50K
Source size Point
Benchmark SON



Lighting for Residential streets / City centres

CRI 20-60
CCT 2000-3000
Lumens 3500-16k lm
Source size Point
Benchmark SON/CDM



Lighting for Signs / Contours

CRI 80
CCT 6500K
Lumens 300-5000lm
Source size Linear
Benchmark Fluorescent



Lighting for Sports

80 Low end
CRI 90 High end
4000k Low end
CCT 5000k High end
Lumens 100k-200k lm
Source size Point
Benchmark MH



Lighting for Industry

CRI 65
CCT 4000k
Lumens 5k-40k
Source size Linear
Benchmark TL


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