Home > Technology > Led lighting

Led lighting

Date post: 13-Jan-2015
Category:
Author: harendra-vishwakarma
View: 1,552 times
Download: 4 times
Share this document with a friend
Description:
 
Embed Size (px)
Popular Tags:
of 20 /20
L L E E D D Lighting Lighting Save Energy Save Your money Save Energy Save Your money Harendra Vishwakarma
Transcript
  • 1. LEDLightingSave Energy Save Your moneyHarendra Vishwakarma

2. LED LIGHT EMITTING DIODELED, a semiconductor diode which when operated in forward biased (switched on),electrons are able to recombine with holes within the device, releasing energy in the formof photons. This effect is called electroluminescence.The wavelength of the light emitted, and therefore its color, depends on the band gapenergy (Eg) of the materials forming the p-n junction. Light The radiant energy that is capable of excite human retina and creating visual sensation. Light by definition connotes Electromagnetic radiation that has a emission in visible part of spectrum (wavelength in the range of 380 nm to about 780 nm) Visible Light 380 nm 780 nm 3. Light Emitting Diode -History 4. MultiChip 5. Structure of LED LED Manufacturing StagesThe Wafer The Substrate on which chipP-Nis grown.junction ElectricalContactsThe Die P-N junction between p-typedoped semiconductor and n-type dopedsemiconductor.The Package Enclosed structure of diein the epoxy or plastic case withappropriate phosphor for colour andlenses for view angle determination. 6. K 7. Selection of LEDs Binning: Variation of color in LED Batch Color Temperature: A measurement of the color of light radiated by a black body while it is being heated. This measurement is expressed terms of absolute scale, or degrees Kelvin. Lower Kelvin temperatures such as 2400K are red; higher temperatures as 9300K are blue. Neutral temperature is white, at 6504K. Forward Voltage Colour Color Rendering Index : To help indicate how colors will appear underdifferent light sources, Lumen Output Lumen output is in mcd for smaller packages and lumen for power LEDs. Trade-off SummaryColor Temperature*EfficacyCRI*EfficacyHeat Efficiency / OutputHeatLife / Durability 8. Availability of various shade of colours 3000 K 3500 K6500 KAppearance of similar product in different CCT Light 9. Reliability Greater Design Flexibility Long Life over 11 yrs(12 hrs a day Various Colors availableoperation) Instant On Lower Life Cycle Cost(Less wattagesgives more lumen & Longer life) Dimming, & Intelligent control. Less Maintenance Cost No IR and UV. Shock & Vibration Proof Wide range of CCT and CRIEfficient Technology Environmental friendly High efficiency No Mercury Due to directional source.(Minimal Less waste creation due to longbackward losses)life. Due to High Lm/W of LED.(Gradually increasing with technology) Less carbon emission. Low Voltage 10. Comparison Between Various Light sourcesPower Consumption for White Light Source Incandescent FluorescentMHLEDVisible Light 7.5 %21 % 27 %15-25 %Infrared73.3 % 37 % 17 % ~0% Ultraviolet 0%0% 19 % 0% Total Radiant Energy80.8 %58 % 63 %15-25 %Heat (Conduction + Convection)19.2 % 42 % 41 %75-85 % Total 100 %100 % 100 % 100 % 11. Comparison of Life of Various Light sourcesLight SourceTypical Typical Rated LumenSystem LifeDepreciation @Efficacy(Hrs)Rated Life(lm/W)Incandescent 10-18750- 200010-15 %Halogen15-20 3,000-4,00030%Incandescent CFL 35-608,000-10,00030%Linear Fluorescent 50-10020,000 30,000 5- 10 % (T5, T8)Metal Halide 50-907,500 20,00020%White LED 5000K60-10050,000-100,000 30 %Warm White LED 45-80 50,000-100,000 30%3300K 12. LED Lamp & Luminaires A luminaire is a lighting fixture complete with the light source or lamp, the reflectorfor directing the light, an aperture (with or without a lens), the outer shell or housing forlamp alignment and protection, an electrical ballast and/or power supply (if required), andconnection to a power source, and usually a light socket to hold the lamp and allow for itsreplacement Simple Model of LED luminaireMore Accurate model of LED luminaire 13. IlluminanceIESNA Definition: the areal density of the luminous flux incident at a point on asurface.Illuminance is calculated as the number of lumens (lm) per unit area.Two common units used to measure illuminance are: footcandles (fc) = lm/ft2 lux (lx) = lm/m2 LuminanceIESNA Definition: the quotient of the luminous flux at an element of the surface surrounding the point, and propagated in directions defined by an elementary cone containing the given direction, by the product of the solid angle of the cone and the area of the orthogonal projection of the element of the surface on a plane perpendicular to the given direction.Luminance is the photometric quantity most closely associated with ones perception of brightness. It usually refers to the amount of light that reaches the eye of the observer measured in units of luminous intensity (candelas) per unit area (m2). IESNA ILLUMINATION ENGINEERING SOCIETY OF NORTH AMERICA 14. MacAdam ellipses and SDCMDimension of a MacAdam ellipse is given by the so called Standard Deviationof Color Matching (SDCM), SDCM characterises the quality of colordifferences1 SDCM 2-3 SDCM4 SDCM No Color difference Hardly any color visibledifference possible Color Difference VisibleSpectral Power DistributionIESNA Definition: A pictorial representation of the radiant power emitted by a light source at each wavelength or band of wavelengths in the visible region of the electromagnetic spectrum (360 to 770 nanometers). 15. Optical instruments: Integrating Sphere Lumen measurement ofluminaire, Chromaticity, Color Rendering Index,Dominant Wavelength, FWHM, Lux meter illuminance (Lux value , Ft-Cd)measurement at specific distance. Luminance Meter Luminance measurements atsurface (Cd/ m2) Spectroradiometer Exact Color and spectrum(W/ m2 sr-nm) Goniophotometer/ Goniospectrometer-Generating IES files for luminaire, polar curves, 16. Thermal Measurements: Thermocouples, (Contact mode method) Temperature profile of LED module and Luminaire with respect to room temperature, Thermocouple needs to be


Recommended