Solid State Lighting:Solid State Lighting: The FutureThe Future is here is here

Xavier FernandoXavier Fernando

Ryerson UniversityRyerson University

Incandescent BulbIncandescent Bulb

LED LampLED Lamp

How Does LED Works?How Does LED Works?

Common LEDsCommon LEDs

White White LEDLED

RGB Based White LEDsRGB Based White LEDsAdvantagesAdvantages

Excellent Color Rendering (faithful color reproduction)Excellent Color Rendering (faithful color reproduction) High lumens/wattHigh lumens/watt Color temperature can be tuned by adjusting the three colors Color temperature can be tuned by adjusting the three colors

separatelyseparately More efficient compared to phosphor based LEDMore efficient compared to phosphor based LED

DisadvantagesDisadvantages Difficult to achieve pure white colorDifficult to achieve pure white color Lamp to Lamp color variationLamp to Lamp color variation

22ou-u u ovvv

(u,v) is the colour coordinates

Blue LED with PhosphorBlue LED with Phosphor

AdvantagesAdvantages Temperature StabilityTemperature Stability Simpler to create than the RGB LEDSimpler to create than the RGB LED Decent colour renderingDecent colour rendering

DisadvantagesDisadvantages Less efficiencyLess efficiency Weak lumens/wattWeak lumens/watt Board emission spectrumBoard emission spectrum Short lift time compare with other type of LEDsShort lift time compare with other type of LEDs

Relative Energy Vs. WavelengthRelative Energy Vs. Wavelength

Comparison of different light sources

Incandescent Light

Phosphor Based LED

RGB Based LED

Power Conversion EfficiencyPower Conversion EfficiencyPower efficiency (lumen-per-watt) is the measurement of the total amount of light emitted by a light sources per energy input.

Directional IlluminationDirectional Illumination

Lights from LEDs can be directed effectively to where it is needed, compensating for their lower luminous efficiencies.

LifetimeLifetime

LED Traffic SignalsLED Traffic Signals

LEDS use 80% to LEDS use 80% to 90% less energy 90% less energy than incandescent than incandescent signalssignals

No need for colored No need for colored filtersfilters

Longer lifeLonger life Reduce Reduce

maintenance costsmaintenance costs

Compared to filtered incandescent signals:

Specific Application: Specific Application: Signs and Signs and Contour lightingContour lighting

Specific application: MSpecific application: Medical edical EquipmentsEquipments

FutureFuture