Proxenon - Leading the future with LED Semi-Conductor Lightings

Edited by Proxenon, Sourced from http://osram.com/products/electronical/optotronic/led_index.html

RBG LED

What is LED?

LED stands for Light Emitting Diode. An LED is a solid state device that converts electric energy directly into monochromatic (single color) light. It is a "PN junction semiconductor diode" that emits light when operated in a forward biased direction. The basic LED structure consists of the die or light emitting semiconductor material, a lead frame where the die is actually placed, and the encapsulation epoxy which surrounds and protects the die.

LEDs employ "cold" light, which means that most of the energy delivered is in the visible spectrum. LED's waste little energy in the form of heat. In comparison, most of the energy in an incandescent light source is in the infrared (non-visible) portion of the spectrum that results in a lot of heat.

In addition to producing cold light, LEDs require much less power than existing lighting solutions, are small in size, resistant to vibration & shock, have a very fast "on-time" (less than 1 millisecond compared to 250 milliseconds for incandescent), have good color resolution, and present low or no shock hazard. The first commercially usable LEDs were developed in the 1960's by combining three primary elements: Gallium, Arsenic, and Phosphorous (GaAsP) to obtain a red light source. As LED technology progressed through the 1970's, additional colors and wavelengths became available. The most common materials were GaP-green and red, GaAsP-orange or high efficiency red, and GaAsP-yellow; All of which are still utilized today. In the 1980's a new material was developed (Gallium, Aluminum, Arsenide (GaAlAs)) that provided superior performance with an increase in brightness of 10x over the previously available LEDs.

Currently, white LEDs are achieved in one of the following three methods:
- Red, Blue, Green (RGB) LED color mixing;
- Coating a Blue LED with Phosphor (typically Yttrium Aluminum Garnet – YAG) so that when energized photons strike the coating it will emit a mixture of wavelengths to produce a white color;
- Coating an Ultra Violet (UV) LED with Phosphor as above.

History of LED - Development for general lighting applications

For more than 30 years, LED have been used in various industrial applications from switch cabinets to measuring instruments, in consumer products such as HiFi- equipment, telephones or personal computers, in traffic signal installations for road and railway or in indoor and outdoor automotive lighting.

History of LED

In the last few years the efficacy of coloured LED increased to amazing 60 lm/W depending on the colour. A trend which will proceed in the future.

As today's white LED reach efficacies up to 15 lm/W - comparable to incandescent lamps - they are more and more used in general lighting. In emergency lighting as well as decorative lighting, they´ve already developed a broad implementation area. Today, also applications such as illuminated advertising benefit from the advantages of LED, particularly by using coloured LED-modules.

All about LED

More and more LED (Light Emitting Diodes) are used in general lighting. We therefore offers a broad range of products from single LED to complete modules.

Basic principles of LED (Light Emitting Diodes)

a LED consists of several layers of semiconducting material
when a LED is operated with DC voltage light is generated in the active layer
the generated light is radiated directly or by reflections
in contrast to lamps, which emit a continuous spectrum, a LED emits light in a certain colour
the colour of the light depends on the used material
two systems of material (AllnGaP and InGaN) are used in order to produce LED with a high luminance in all colours from blue to red and also in white (luminescence conversion). Therefore different voltages are necessary in order to operate the diode in conducting direction

LED for general lighting

Mainly white light is used for general lighting applications. The white LED with efficacies from 11 - 15 lm/W - which is comparable with our good old incandescent bulb - is only availble for a few years. The operating principle consists of a LED-chip whose blue radiation excites yellow fluorescent particles mixed with the resin. The emission of blue and yellow light finally results in white light.

The future of light?

Innovative LED offer a number of technological advantages:

Low energy consumption - Save up to 90% electricity
Extremely long life - Upto 100,000 hours operating life
Very low early failure rate - Less than 1/100000 failure rate
Smallest dimensions
Shock and vibration resistant
No ultra-violet or infrared radiation
Low wattage
Almost no heat generation
Directed light through optical lenses
High colour efficiency

The benefits for users are as follows:

Creative design options due to a multitude of available colours, compact dimensions and flexible modules
High economical efficiency due to low energy consumption, long life and low maintenance cost
Highest reliability even under difficult conditions

Reference Application

Orientation with LED-lighting
LED Fixture Lights, mounted in stairs and operated by OPTOTRONIC lead the way in the famous "Gewandhaus" in Leipzig/Germany.
LED in indoor lighting
The first complete indoor lighting installation with LED was designed by Bartenbach Lichtlabor in Innsbruck /Austria. White light is created by a perfect mix of 14,000 white and coloured LED.
Illuminated advertising with LED

For illuminated signs, Color LED-modules are a new alternative to conventional light sources (Neon). Numerous companies use already LED-modules illuminated advertising. Here in Proxenon, we have various item to choose from...

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