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FUNDAMENTALS February 2014 - Version1

LED Fundementals

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LED Fundementals

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FUNDAMENTALS

February 2014 - Version1

Content

• Lighting Industry – Transformation to LED• LED Timeline• LED Penetration

• What is LED?• LED Working Principle• LED Manufacturing Stages• Zhaga Consortium• LED Binning• Circuits & System LED• White / RGB LED• LED Power Supply or Driver• Thermal Management• Temperature Vs LED Performance• LED Optics

• LED System Efficacy• LED System Quality & Reliability• LED Useful Life

• LED Standards – IES LM – 79-08• LED Standards – IES LM – 80-08• Comparisons: 60x60 Luminaire Suspended Luminaire Down light• Case Study – SLC Die Casting Area• Case Study – SLC Die Casting Area• Advantages of LEDs• Disadvantages of LEDs• LED Lighting Green Revolution

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Lighting Industry - Transformations to LED LED Timeline

• 1962- First RED LED Developed by Nick Holonyak @ GE.• RED INDICATOR LED’s Manufactured by HP (0.1 lm)• First green & Yellow LED’s introduced

• 1993 – HBM BLUE LED’s by Shuji Nakamura @ Nichia.• 1995-High brightness green LED’s.• 1996-First White LED’s developed.• Ultra bright RED & Amber LED’s• LED’s began to replace incandescent sources.• LED’s become viable for portable illumination applications.• 1998-RGB Lighting Applications.

• White Light via RGB LED’s.• White light Via Blue + Phosphors.• First tunable White Light LED Fixtures.• LED’s available in 10-100 lumens.• 2003-LED’s widely accepted in entertainment Lighting.• 2004-White LED’s become viable for accent lighting.• 2005-1000+ lumen LED’s via multichip packages.• 2008-LED’s become viable for general illumination.

• 1971-First Blue LED ‘s generated.• 1972-1 lm RED LED’s available.• LED’s used in watches, calculators etc.

• 1980-Advances in Lumen Output.• 1984-First Super bright RED LED’s generated.

2000

1990

1980

1970

1960

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• Current Lighting technology is 120 years old.• LED’s began as just indicators, but are now poised to become the most efficient light source ever created.

MERCURYVAPOUR LAMP INTRO.REFLECTOR LAMP INTRO.

ELECTRODLESS LAMPS INTRO.INDIUM GALLIUM NITRIDE LED’S INTRO.

CFL’S INTRO.HIGH FREQ. BALLASTS INTRO.

INDIRECT LIGHTING DEMO

WHITE LED (EFFICACY ≥100lm/W)

HIGH POWER WHITE LED’SMETAL HALIDE LAMP INTRO.PAR LAMP INTRO.

1950 1960 1970 1980 1990 2000 2010

500BC3000BC 1800 1900 1910 1920 1930 1940

OIL LAMPSCANDLES

GAS LAMPELECTRIC ARC LAMP DEMO

TUNGSTEN HALOGEN INTRO.HPS LAMP INTRO.

FIRST PRACTICAL LED INTRO.

EDISON ELECTRIC LAMP NEON LAMP DEMO FL. LAMP INTRO.

LED Penetration

LED Forecast

* Source: Philips Lighting

€ 100€ 90€ 80€ 70€ 60€ 50€ 40€ 30€ 20€ 10€ 0

Global General Illumination Market*

2008

2010

2012

2014

2016

2018

2020

Rev

enue

( Bi

llion

s)

What is LED?

A light emitting diode (LED) is essentially a PN junction opto-semiconductor that emits a monochromatic (single color) light when operated in a forward biased direction.

LED Source is a Solid State Light source – semiconductor component • A semiconductor device that converts electrical energy directly into

discrete color of light• Made from different materials and substrates • Made in chip fabrication factories• No brass, glass and and gass (“solid state”)• White LED Sources are a blue LED device + phosphor

5mm LED High power LED

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LED Working Principle

• LEDs are semiconductor diodes• Semiconductors are materials with ability to conduct electrical current• Diodes are formed by combining two different semiconductor materials to form

a PN junction (P=charged positive(holes) and N charged negative(electrons)• By applying current, electrons(N) are forced to move to one direction and P to

the opposite direction• Photons (basic unit for electromagnetic radiation) are generated when the

positive and negative charges recombine

LED Manufacturing Stages

International brands from Lighting and Electronics industries (Tridonic, Samsung, Philips, Osram, …)

GLC portfolio

Level 1

Die Sub - Assembly Modules Luminaires Solutions

Level 2 Level 3 Level 4 Level 5

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Zhaga Consortium

• Zhaga is a consortium of companies from throughout the international lighting industry. The organization is developing specifications that will enable the interchangeability of LED light sources made by multiple different manufacturers. www.zhagastandard.org

• Zhaga is an industry-wide collaboration between companies from across the globe. Members are luminaire manufacturers, LED module makers, material and lighting component suppliers as well as service providers such as laboratories.

• Zhaga’s goal is to develop and publish interface specifications that cover the physical dimensions, as well as the photometric, electrical and thermal behavior, of LED light engines.

• The individual specification documents, also known as Books (8 books), cover different types of LED light engines that are suitable for a range of applications.

• Since Zhaga was founded in February 2010, membership has grown to several hundred companies , example: BJB Gmbh, Fulham, GE, Osram, Philips Lighting, etc.

LED Binning8 9

Circuits & SystemLED

Combination of electronic parts, wires connected using suitable controlling & regulating devices between suitable power sources. They each have a physical property that interacts with electricity. When put in combination various actions occur.

An LED will light up when enough voltage is supplied but can also burn out if too much is allowed to pass through. The resistor will limit the voltage to prevent damage.

Parts :• LED’s (White / RGB)• Driver/Battery (Power Source)• Resistor / Capacitors• PCB’s / Terminals• Wires• Controls• Thermal Management• Optics

White / RGB LED

• Generates white light in a single LED by combining a blue (or UV) LED with a yellow phosphor coating

• Coating converts some blue photons into yellow photons

• Blue and yellow photons combine to generate white light

• Offers superior color rendering and efficiency

• Preferred method for producing LED white light

• Tri-color (RGB) LED fixtures combines red,

• Blue, and green in varying intensities to generate millions of colors

By Changing the Resistance / by controlling it using a potentiometer, you can play w/- various color combinations.

Phosphor coating converted LED Source

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LED Power Supply or Driver

• LED’s are typically driven by a constant-current DC power source

• High brightness or power LED generally refers to an emitter package of roughly 1.2W at a drive current of 350 mA

• The light output of an LED is proportional to current applied, most high brightness LED sources will operate across a range of current

• Drivers also contain temperature sensitive electronic components

• There is energy lost in the power supply efficiencies can vary from 90% all the way down to 50% or lower

Thermal Management

• LED’s produce a fair amount of waste heat

• Excess heat reduces light output and shortens useful life

• Therefore, LED fixture design must effectively channel heat away from LED sources

• Thermal management features typically include an effective thermal path and heat sink.

• A heat sink is typically required to dissipate the heat produced by LED sources

• The interface between the circuit board and the heat sink is critical due to the heat sisitive nature of LED sources

• A thermally conductive material is typically used between the PCB and heat sink to minimize air gaps which reduce the transfer of heat

Passive Cooling

Active Cooling

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Temperature Vs LED Performance

Thermal management of LEDs plays the most important role in achieving the promised life-time

• Light output goes down as junction temperature goes up

• 100 % Lumen output @ 25°C Tj goes down to 85% Lumen Output @ 80°C Tj

Source: Cree

• Life is directly related to junction temperature

LED Optics

• Primary optics are frequently part of the LED source• Secondary optics are utilized to redirect light to produce a specific

pattern, distribution or beam of light• Secondary optics can consist of lenses, reflectors, light shaping films or

a combination of these elements• Some light is lost each time it is reflected or refracted, these are the

optical losses

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LED System Efficacy

LED LED array Optics Driver Luminaire

• Color temperature• Temperature (Tj)• Drive current

• Thermal losses (higher Tj)

• Optical losses • Driver losses

-10-30% -10%-50%-10-15%

100 lm/W 85 lm/W 70 lm/W 50lm/W system efficacy

Lm/W relation from LED component to the complete luminaire system

LED System - Quality & Reliability

System Reliability # single LED Reliability

Rsystem = Relectrical * Rconnections * Roptical * Rthermal * Rmechanical* RLEDs

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LED Useful Life

• Changes in general office lighting levels go largely undetected as long as light levels stay above 70% of their initial levels, especially if the changes are gradual.

• Useful life is defined as the length of time it takes an LED light source to reach 70% of its initial light output (L70).

• Typical (L70) number is 50,000 hours.

Light Source Typical Range (Hours)

Incandescent 750-2,000 / rated life

Halogen Incandescent 2,000-4,000 / rated life

CFL 8,000-10,000 / rated life

Metal halide 7,500 – 20,000 / rated life

Linear Fluorescent 20,000 – 30,000 / rated life

White light LED 35,000 – 50,000 / useful life (L70)

LED Standards –IES LM-79-08

The IES (Illuminating Engineering Society) Published the following publications:• IES LM-79-08, Approved Method: Electrical and Photometric

Measurements of Solid-State Lighting Products.This document defines measurement related to an LED luminaire or integral lamp as a whole system according to a standard process using specified equipment.

LM-79-08 testing report will provide:- Total Luminous Flux - Luminous Intensity Distribution - Electrical Power Characteristics - Luminous Efficacy (calculated) - Color Characteristics (CRI, CCT…)

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LED Standards –IES LM-80-08

• IES LM-80-08, Approved Method : Measuring Lumen maintenance of LED Light Sources.

LM-80-08 apply to the LED package, array, or module alone, not a complete system.

The testing report issued according to a standard format will provide luminous flux for a given current over a 6,000 hours period with interval measurements.

Luminous flux will be measured for 3 different LED case temperatures: 55ºC, 85ºC and a third temperature to be selected by manufacturer. Besides, the lumen maintenance, the chromaticity shifts over the measured period

60x60 luminarie comparisons

Sn Criteria 5700 GU/418, 4/18W,T8 Luminaire LED (60x60)1. Pictures

2. AC Voltage Range (V) 220-240 198-264

3. Power Factor @230V 0.95 0.95

4. Lamp Power (W) 18W x 4,T8 LED, 11.6W x 4

5. Lamp Efficacy (lm/W) 75 106

6. Driver ECG ECG @ 350mA,33.7V

7. Driver Efficiency @230V (%) 92 94.5

8. System Efficacy (lm/W) 40 74

9. Total Power (W) 72 51.2

10. Lumen / Source (lm/Source) 1350 1250

11. Total Lumens (lm) 2855 3794

12. Switch On time (s) Instant 0.4s (Instant)

13. Life in Hours 15,000( based on oprtn. mode) 50,000

14. Re-lamping 4 lamps @ 3 to 4 times. Absolutely Zero

15. CRI (Ra) >80 >80

16. Rough Cost Estimate ~ 400SR ~ 1100 SR

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Suspended luminarie comparisons

Sn Criteria 2/36W, T8 2/28W,T5 Dune Kato1. Pictures

2. AC Voltage Range (V) 220.240V 220-240 198-264 198-264

3. Power Factor @230V 0.95 0.95 0.95 0.95

4. Lamp Power (W) 2x36W,T8 2x28W,T5 LED, 11.6W x 4 LED, 11.6W x 4

5. Lamp Efficacy (lm/W) 80 93 131 131

6. Driver ECG ECG ECG@ 350mA,33V ECG @ 350mA,33V

7. Driver Efficiency @230V (%) 92 92 94.5 94.5

8. System Efficacy (lm/W) 40 67 71 90

9. Total Power (W) 72 61 46.4 46.4

10. Lumen / Source (lm/Source) 2850 2600 1440 1440

11. Total Lumens (lm) 4289 4089 3296 (w/- Opal) 4191

12. Switch On time (s) ≤1s Instant 0.4s (Instant) 0.4s (Instant)

13. Life in Hours 15,000 18,000 50,000 50,000

14. Re-lamping 2 lamps @3 to 4 times. 2 lamps @ 3 times. Absolutely Zero Absolutely Zero

15. CRI (Ra) >80 >80 >80 >80

16. Rough Cost Estimate ~ 250 SR ~ 250 SR ~1220 SR ~810 SR

Downlight comparisons

Sn Criteria 5870C (2CDE26W) LD103 (1100 lm) LD103 (2000 lm)1. Pictures

2. AC Voltage Range (V) 220-240 (+/-10%) 220-240 220-240

3. Power Factor @230V 0.95 >0.9 >0.9

4. Lamp Power (W) 26 x 2 14 28W

5. Lamp Efficacy (lm/W) 63 -- --

6. Driver ECG Philips Integrated Driver Integrated Driver

7. Driver Efficiency @230V (%) 92% Driver in built Driver in built

8. System Efficacy (lm/W) 23 42 28

9. Total Power (W) 56 18W 32W

10. Lumen / Source (lm/Source) 1650 1100 2000

11. Total Lumens (lm) 1286 630 (w/- Opal), 760(w/o diff) 894 (w/- Opal)

12. Switch On time (s) Instant Instant Instant

13. Life in Hours 10,000 25,000 25,000

14. Re-lamping 2 lamps @ 2.5 times. Absolutely Zero Absolutely Zero

15. CRI (Ra) >80 80 80

16. Rough Cost Estimate ~ 325 ~ 550 SR ~ 660 SR

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Case Study - SLC Die-Casting Area

LED 141W @ 15pcsMetal Halide 400W @ 18pcs

Case Study - SLC Die-Casting Area

• INITIAL COST OF RETROFIT (LED) ✔ LUMINAIRE + INSTALLATION COST : SAR 27,300.00 (approx.)• ANNUAL ELECTRICITY COMSUMPTION ✔ HID • 460W x 24 hr x 365 days x 18qty= 72,532 KW-Hr ✔ LED • 141W x 24 hr x 365 days x 15qty= 18, 527 KW-Hr• SAVINGS ◆ ELECTRICITY(ANNUALLY) = SAR 7,159.00 ◆ MAINTENANCE COST = SAR 3,600.00 ◆ LAMP REPLACEMENT = SAR 6,750.00

• NOTE: Labor cost are based on sr20 per hour and 2 manpower

• TOTAL COST OF OWNERSHIP (FOR 7 YEARS)HID • ELECTRICITY COST + MAINTENANCE COST + LAMP

= SAR 77,662LED • ELECTRICITY COST + LUMINAIRE COST = SAR 44,506

PAYBACK TIME ✔ Initial investment / savings ✔ 3.24 years RETURN ON INVESTMENT ✔ Yearly savings / installation cost ✔ 32%

CRITERIA’S HID LUMINAIRES LED LUMINIARES

NUMBERS OF LUMINAIRES 18 15

ILLUMINATION LEVEL 200 LUX >300 LUX

TOTAL POWER CONSUMPTION 460W x 18 = 8.28 KW 141W x 15 = 2.11KW

LAMP LIFE MH ->12 000 Hr 100 000 Hr @ 25°C(manufacturer claims)

COLOR TEMPERATURE 5500K 5650K

RENDERING INDEX (CRI) 90 >70

MAINTAINANCE ANNUALY OR SEMI-ANNUALLY LESS MAINTENANCE DUE TO HIGH IP

RE - LAMPING EVERY 12 000 HR or LESS NO LAMP REPLACEMENT

SWITCHING OPERATON 20 MIN TO REACH OUTPUT INSTANT ON

DIMMING CAPABILITIES NOT DIMMABLE DIMMABLE

OCCUPANCY SENOR NOT POSSIBLE CAN BE INTEGRATED

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Advantages of LEDs

Sn Criteria Advantages

1. Size LEDs can be very small and are easily arranged onto printed circuit boards.

2. Frequent Switching LEDs are ideal for use in applications that are subject to frequent on-off cycling, unlike fluorescent lamps that burn out more quickly when cycled frequently

3. Efficiency LEDs produce more light per watt than incandescent bulbs. Their efficiency is not affected by shape and size, unlike Fluorescent light bulbs or tubes.

4. Light Direction / Focus Uni-directional – Focusing of light is also possible.

5. Slow deterioration LEDs mostly fail by dimming over time & no abrupt burnt out

6. Shock resistance LEDs, being solid state components, are difficult to damage with external shocks, Vibrations or impacts,

7. Toxicity LEDs do not contain mercury or similar toxic materials

8. Color LEDs can emit light of an intended color without the use of the color filters that traditional lighting methods require.

9. Dimming LEDs can very easily be dimmed either by pulse-width modulation or lowering the forward current.

10. Cool Light LEDs radiate very little heat in the form of IR that can cause damage to sensitive objects or fabrics. Wasted energy is dispersed as heat through the base of the LED.

11. Lifetime LEDs can have a relatively long useful life. One report estimates 35,000 to 50,000 hours of useful

12. Switching Response time LEDs light up very quickly. LED’s have faster response time.

13. Maintenance Maintenance mostly limit to cleaning of fixture, So it is often considered as Zero Maintenance light source.

14. Lighting Controls Possibility of Controlling the RGB of LED sources by PC (DMX) Protocols to create changing luminous ambiences.

Disadvantages of LEDs

Sn Criteria Disadvantages

1. Blue Light Hazard Photobiological safety for Lamp and Lamp Systems shall be ensured by procuring LED’s from a reputable environmental friendly manufacturer.

2. Temperature Dependence

LED performance largely depends on the ambient temperature of the operating environment. Over-driving the LED in high ambient temperatures may result in overheating of the LED package, eventually leading to device failure. This ensures the importance of tested & certified products.

3. Voltage / Current Sensitivity

LEDs must be supplied with the voltage above the threshold and a current below the rating. This can involve series resistors or current-regulated power supplies.

4. Initial Price LEDs are currently more expensive, price per lumen, on an initial capital cost basis, than most conventional lighting technologies.

5. Polarity Issues Polarised components ensures the importance of qualified suppliers & technicians for assembling the unit.

6. LED Testing Standards Most of the LED Standards were under development & very less manufacturer’s follow those standards in actual applications.

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LED Lighting Green Revolution

Slide 6 – LED Lighting Green Revolution

• Lighting consumes 19% of all electrical usage worldwide

• Widespread LED usage could reduce global lighting energy usage by as much as 50%

• LED lighting could decrease carbon dioxide emissions from electric power use by as much as 50% over the next 20 years

• Reducing energy usage is only the beginning

• LED sources have a long useful life, which means fewer lamp replacements

• Unlike CFL’s and incandescent lamps, LED sources do not contain lead and mercury

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