Principles of LEDS

April 07

Udo van Slooten

PCT Special ApplicationsBusiness Unit Solid State Lighting

2Philips Lighting BU Solid State Lighting – PCT Special Applications

Principles of LED’s

Benefits of LEDs

LED Technology General

Optical Characteristics

Binning

White Light

Thermal and Electrical behavior

3Philips Lighting BU Solid State Lighting – PCT Special Applications

Benefits of LEDs (1)

General: • Much longer life (50K Hours)• Reduced maintenance costs• More energy efficient than incandescent and

Halogen lamps• No IR radiation or UV in the beam• Highly efficient plastic optics can be used

Architectural/design:• Design flexibility, hidden light широкие возможности дизайна, скрытые

источники света

• Vivid saturated colors - without filters• Directed направленный light for increased system

efficiency• Robust надежное, vibration proof, solid state lighting• Lower light pollution, due to better optical control

4Philips Lighting BU Solid State Lighting – PCT Special Applications

Benefits of LEDs (2)

Unique LED advantages:• Dynamic color control, white point tunable• Fully dimmable without color variation• Instant on, full color, 100% light• No efficiency loss due to filtering• Install and forget

Environment:• No Mercury in the light source

Safety/low temperature:• Cold start capable (down to -40°C)• Low voltage DC operation работа на постоянном токе низкого напряжения • Highly efficient in cold environment• Sealed герметичны for life waterproof luminaries

5Philips Lighting BU Solid State Lighting – PCT Special Applications

LED Technology: LED Principle

LED means: Light Emitting DiodeSemiconductor Light Source

Cu

rren

t [m

A]

Voltage [V]

350

2.6 3.5

LED Electrical Characteristic

6Philips Lighting BU Solid State Lighting – PCT Special Applications

LED Technology: LED Principle

Energy level high

Energy level low

Junction

Photon

7Philips Lighting BU Solid State Lighting – PCT Special Applications

LED Technology: LED Principle Electron Energy энергия электрона vs Wavelength

Blue lightHigh Energy

Red lightLow Energy

Increase of energy

8Philips Lighting BU Solid State Lighting – PCT Special Applications

LED Technology: Material Systems материалы для светодиодов

AlGaAsAlInGaP

InGaN

Wavelength [nm]

Диапазон энергии Energy of the electron in [eV]

1.752.002.252.502.753.003.253.50

350 400 450 500 550 600 650 700 750 800

Yellow gap : No LEDs available between 550 and 585nm

9Philips Lighting BU Solid State Lighting – PCT Special Applications

LED Technology: Definition of levels уровни светодиодов, определение

Level 0

LED-Chipкристалл

Level 1

LED or

lampДискретный

элемент

Level 2

LEDs on PCBсборка

Level 3

LED module with optics and

driverИнтегриро-ванная

система = уровень 2 + оптика и блок питания

Level 4

LuminaireГотовый светильник

10Philips Lighting BU Solid State Lighting – PCT Special Applications

LED Technology: Type of LEDs

Surface mount LEDs(SMD)- Indicators in: - computers- cars- mobile phones

Through hole Superflux and 5mm LEDs- Indicators- Third brakelights стоп-сигналы

LUXEON LEDs:- Traffic signals светофоры

- General illumination- Torches- Entertainment industry

INDICATORSSIGNAGE

ILLUMINATION

11Philips Lighting BU Solid State Lighting – PCT Special Applications

LED Technology: Type of LEDs : 5mm LED vs Philips LUXEON

Light Emitted Forward

LED Chip

Reflector

PC Board

Cathode Lead Anode Lead

Cathode Lead

Gold WireЗолотой проводник

Heatsink Slugтеплоотвод

Reflector Cup

Solder ConnectionПаяное соединение

Plastic Lens

SiliconeEncapsulate

InGaNSemiconductorFlip Chip

Light Emitted Forward

12Philips Lighting BU Solid State Lighting – PCT Special Applications

LED Technology: Type of LEDs : Philips LUXEON K2

Silicon Lens

Chip or die кристаллBuilt-in heat sink to transfer of heat to

(MC)PCB

Plastic Housing

Electrical connections

разъемы

Bond wire соединитель

13Philips Lighting BU Solid State Lighting – PCT Special Applications

LED Technology: misconception: “all LEDs last 50,000 hours or longer”

0%

20%

40%

60%

80%

100%

10khrs 20khrs 30khrs 40khrs 50khrs

Typical 5mm LED

Typical superflux ledвысокояркий

Typical LUXEON led

Philips specifies useful life in hours and light output.The Affinium LED string uses superflux type LED’sThe Medium Power string uses Luxeon type LED’s

Time (hrs)

Light output

14Philips Lighting BU Solid State Lighting – PCT Special Applications

LED Technology: Type of LEDs Overview

5mm LEDs SMD LEDs LUXEON I and III

LUXEON K2

Powerмощность

0.3 W 0.5 W 1 – 3.5 W 1 – 5 W

Flux Whiteпоток

1-3 lm 0.1 – 12 lm 45 – 80 lm > 80 lm

Lens epoxy epoxy Silicon and plastic

Silicon

Temp. Range(junction)

Max. 120 °C Max. 120 °C Max. 135 °C Max. 165 °C

Lifetime white LED

5 khrs 20 - 50 khrs 20 – 50 khrs

15Philips Lighting BU Solid State Lighting – PCT Special Applications

Optical Characteristics: Lambertian Radiation Pattern Ламбертова диаграмма направленности излучения

0

10

20

30

40

50

60

70

80

90

100

-100 -80 -60 -40 -20 0 20 40 60 80 100Angular Displacment (Degrees)

Rel

ativ

e In

ten

sity

(%)

Typical Upper Bound

Typical Lower Bound

Angular Displacement (Degrees) угловое смещение (градусов)

Rel

ativ

e In

ten

sity

(%

)

Typical Lower Bound

Typical Upper Bound верхняя граница

16Philips Lighting BU Solid State Lighting – PCT Special Applications

Optical Characteristics: Batwing Radiation Pattern диаграмма направленности излучения

0

10

20

30

40

50

60

70

80

90

100

-100 -80 -60 -40 -20 0 20 40 60 80 100Angular Displacement (Degrees)

Re

lati

ve

In

ten

sit

y (

%)

Typical Upper BoundTypicalLower Bound

Angular Displacement (Degrees)

Rel

ativ

e In

ten

sity

(%

)

Typical Upper Bound

Typical Lower Bound

17Philips Lighting BU Solid State Lighting – PCT Special Applications

Binning

Bin 1

Bin 3

Bin 2

LEDs are binned on:• Flux• Color• Forward Voltage прямое напряжение

INPUT PRODUCTS

OUTPUT

Flux [lm]поток

# o

f pro

duc

ts

# o

f pro

duc

tsFlux [lm]

18Philips Lighting BU Solid State Lighting – PCT Special Applications

Binning: Example binning structure

Dominant wavelength bin structure for cyan LUXEON,LUXEON K2, LUXEON III and LUXEON V emitters and arrays.

Bin CodeMinimum Dominant

Wavelength (nm)Maximum Dominant

Wavelength (nm)

1 490495

2495 500

3500 505

4505 510

5510 515

6 515520

19Philips Lighting BU Solid State Lighting – PCT Special Applications

White Light: White LED principle

Blue LED Chip

Phosphor

Yellow PhotonBlue Photon

Blue Photon

LED Chip

20Philips Lighting BU Solid State Lighting – PCT Special Applications

Thermal Behavior температурные характеристики of LEDs

Cathode Lead

Gold Wire

Heatsink SlugReflector Cup

Solder ConnectionПаяное соединение

Plastic Lens

SilliconeEncapsulent

InGaNSemiconductorFlip Chip

Light Emitted Forward

Heat

• LEDs emit “cold” Light and no IR or UV• LEDs are not 100% efficient => Heat (50%)• LEDs can not withstand high temperatures (125°- 150°)

We have to take care of good heat sink possibilities, to get the best life-time

21Philips Lighting BU Solid State Lighting – PCT Special Applications

Thermal Path LED application тепловой мостик

LED Chip with junction спайка

LED Heat sink or slug сердечник

(Metal Core) PCB spreading the heat

Heat Sink transferring the heat to ambient

Moving air (natural convection)