LEDs A BASIC INTRODUCTION

Transcription

1 LEDs A BASIC INTRODUCTION

2 High Power LEDs Function and construction History Power, flux and luminous efficiency Color and binning LED optics

3 LED: Solid State Lighting Electroluminescence The light is emitted by a solid body, neither by a gas nor by a glowing filament

4 LED Principle of Light Emission Silicon pdoped Silicon ndoped LED = Light Emitting Diode Recombination

5 Construction of an LED

6 LED Monochromatic Light Emission InGaN chip AlInGaP chip

7 LED Only Monochromatic Light Emission??

8 LED Monochromatic Light Emission RGB superposition Partial phosphorescence conversion

9 Dynamic Color Applications Color mixing

10 LED types 5 mm LED Cree XRE Osram Golden Dragon Cree MCE High Brightness SMD LED Luxeon Rebel Avago RGB Edison Edipower 50 W

11 LED types 5 mm LED max. 0.1 W < 5 lm High Brightness, Medium power SMD LED max. 0.5 W < 20 lm High power LED min. 1 W > 40 lm

12 OSRAM Cree Lumileds Nichia Important Players on the High Power LED Market Seoul Semiconductor Edison Samsung

13 LED History 1962 First red LED (GaAs) 0,1 lm/w ~1965 Yellow LED (GaAs/AlAs) 1968 Green LED (GaAsP) 1988 Blue and UV LED (GaN) 1990 High brightness LED blue (InGaN) 1994 High brightness LED red yellow (AllnGaP) 1997 First white LED (Nichia) 2007 Cool white LED 100 lm/w

14 LED Properties Flux Power consumption Luminous efficiency Color Color temperature Color rendering index Lifetime / Maximum operating temperature

15 Are LEDs the Most Efficient Sources?

16 LED Luminous Efficacy compared to other light sources 2012: ~150 lm/w LED

17 LED Improved Utilization Factor HID 100 lm/w White LED 80 lm/w 50% utilization efficiency 70% utilization efficiency Lighting efficiency50 lm/w Lighting efficiency56 lm/w

18 Functional Street Lighting with LED Pilot Installation LED HPS

19 Colored LED An Efficient Choice HID blue filter Blue LED Source spectrum Filter spectrum LED spectrum

20 Colored LED an Efficient Choice HID blue filter Efficacy: /90 lm/w Filter transmission max. 10 % 9 lm/w Blue LED Efficacy: 25 lm/w Saturated Colors

21 Warm White or Cool White? Warm White Cool White Warm White: thicker phosphorous layer different phosphorous composition CRI up to 8090 (cool white 7075) Reduction of luminous efficiency (~ 30 %)

22 Binning Binning: Classification of the LED after the production process according to Color Flux Forward voltage The choice of an appropriate binning is crucial for the quality of the luminaire!

23 Different Binning Structures Warm White K 2700K 2500K CCy Cool White 7000K 8000K WF 6000K WG WD Neutral White 4000K 4500K 6B 5000K 5C 5B 6A 4C 5D 4B 5A 3C WH 3B 4D 4A 3D 3A WJ 3500K 6C 7A 6D 7B 7D 7C 8A 8B 8D 8C BBL 0.32 WE WC 9000K 0.31 WB WN K WM WA 0.29 WK 0.28 WP Cree CCx Osram Lumileds

24 Effect of the Binning on the Price y coordinate 0,50 0,48 0,46 0,44 0,42 0,40 0,38 0,36 0,34 0,32 0,30 0,28 0,26 0,24 0,22 0,20 Color Area of Nichia W hite & W arm W hite Color Coordinates 7000k 5600k 4600k 9000k 15000k b3 a 0 Blackbody Locus 3800k k K f3 f4 e1 d1 c1 f6 f5 b4 e2 d2 c2 b6 b5 2800k K 2500k K 0,20 0,22 0,24 0,26 0,28 0,30 0,32 0,34 0,36 0,38 0,40 0,42 0,44 0,46 0,48 0,50 x coordinate Flux Bin Min Max Rank P17 86 lm 102 lm Rank P16 72 lm 86 lm Rank P15 60 lm 72 lm Rank P14 51 lm 60 lm Color rank Flux rank Price b5/b6 P14/P15/P % b3/b4/b5/b6 P14/P15/P16 90 % f3/f4/f5/f6 P15/P16/P % f4/f6 P15/P16/P % f4/f6 P16/P17 1, % The range of the bin has a significant effect on the LED price

25 Lifetime / Maximum operating temperature

26 LED System LED luminaires are part of an integrated system thermal mechanical electronic optical

27 Advantages of LEDs No heat or UV in the light beam Directional lighting for high system efficiency No toxic vapors Long lifetime Small sources Design flexibility High efficiency for color applications Saturated colors Instantaneous illumination Dynamic color control Dimming by pulse width modulation High resistance to impacts and vibrations Low operating DC voltage high security High CRI (up to 90) Operating at low temperatures

28 Disadvantages of LED High thermal losses to be dissipated Lifetime and flux strongly depending on the temperature Efficiency for white light still lower compared to discharge sources Constant current source required Lifetime and efficiency of electronic components vary with temperature Absence of standardisation of LED performances