Solid State Lighting: The Future is here Xavier Fernando Ryerson University

Incandescent Bulb

LED Lamp

How Does LED Works?

Common LEDs

White LED

RGB Based White LEDs Advantages  Excellent Color Rendering (faithful color reproduction)  High lumens/watt  Color temperature can be tuned by adjusting the three colors separately  More efficient compared to phosphor based LED Disadvantages  Difficult to achieve pure white color  Lamp to Lamp color variation (u,v) is the colour coordinates

Blue LED with Phosphor Advantages  Temperature Stability  Simpler to create than the RGB LED  Decent colour rendering Disadvantages  Less efficiency  Weak lumens/watt  Board emission spectrum  Short lift time compare with other type of LEDs

Relative Energy Vs. Wavelength

Comparison of different light sources Incandescent Light Phosphor Based LED RGB Based LED

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

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

Lifetime

LED Traffic Signals  LEDS use 80% to 90% less energy than incandescent signals  No need for colored filters  Longer life  Reduce maintenance costs Compared to filtered incandescent signals :

Specific Application: Signs and Contour lighting

Specific application: Medical Equipments

Future