Lighting Emitting Diode Tutorial

What is an LED?
You may not even know it but light-emitting diodes (LEDs) are everywhere. That red light you see shimmering from your digital clock at night ­ Yup LEDs. That green light emitting from your cell phone ­ Guess again - LEDs! Digital-message signs, pinball machines, automobile dashboards, streetlights, and even those little indicator lights shining back from your computer RIGHT NOW.

As engineers are discovering higher intensities and different colored LEDs, the power and versatility of LEDs grows. The very best part is that Color Kinetics has captured the benefits of LED advancements to create amazing patented technologies that enable the creation of cool color-changing effects. Color Kinetics products are creeping up everywhere; soon to be a staple in applications ranging from cruise ships to bars limited only by your imagination!

What's so different?
Well, first let's take a look at the traditional light bulb. The light in most homes is produced by incandescent light bulbs. The bulb structure is produced when hot glass is blown into molds and then cooled and coated with diffusing material. Placed inside the bulb is a very thin and fragile, coiled tungsten filament (.0017 inches thick). For the bulb to produce light an electric current is passed through a conductor and the tungsten is heated to the point at which it gives off light. Unfortunately, these bulbs, like many of its relatives, are not very energy efficient; roughly 10% of the energy is used to make visible light.

How do LEDs work?
First off, the structure of the LED is completely different than that of the light bulb. Amazingly the LED, the light of the future, has a simple and strong structure. This makes it easier to explain and easier for you to understand! Phew!

The beauty of the structure is that it is designed to be versatile allowing for assembly into many different shapes. Since Color Kinetics uses mostly the lamp structure, we will focus our demonstration on this assembly. The four basic components of a LED Lamps are:

• Light emitting semiconductor material or die mounted on a "reflector cup." This material is what determines the LED's color.
• A cathode and anode lead
• Bonding wire connecting the anode post to the cathode post
• An epoxy dome lens to protect the die and determine beam shape

Now, remember LED stands for Light Emitting Diode. So the LED is a diode that emits light and a diode is a device that allows current to flow in only one direction. Almost any two conductive materials will form a diode when placed in contact with each other! When electricity is passed through the diode the atoms in one material (within the semiconductor chip) are excited to a higher energy level. The atoms in that first material have too much energy and need to release that energy. The energy is then released as the atoms shed electrons to the other material within the chip. During this energy release light is created. The color of the light from the LED is a function of the ingredients (materials) and recipes (processes) that make up the chip.

What are the advantages of LEDs? It is not like us to brag, however, LEDÕs have a variety of reasons why they are preferred over other light sources:

• High-levels of brightness and intensity
• High-efficiency
• Low-voltage and current requirements
• Low heat
• High reliability (resistant to shock and vibration)
• No UV Rays
• Can be easily controlled and programmed

What are the disadvantages of LEDs?
If we left this question out, you would most likely be wondering what we are not telling you. So here is your answer, there are virtually NO disadvantages with LEDs. In the past the major complaints you may have heard were "LEDs are not bright enough" or "their color fades". In recent years, the technological advances have silenced these complaints.

Why are LEDs becoming so popular?
Over the past decade, LED technology has advanced at light speed. In the past, lack of colors and the low intensity made LEDs useful only as indicator lights. As manufacturing methods and technology improved, the LED quickly found homes in more and more applications. These days, it is seen that the LED is becoming a preferred light source for much more than simple indicators. The best example of this is in what we at Color Kinetics use them for, to add colorful, customizable light to your life.

Summary
Today is an exciting time for those working closely with LED applications. Lighting designers and architects are just now realizing the control and beauty that comes only from LEDs, causing the LED marketplace to expand at an amazing rate. It is Color Kinetics patented technology, Chromacore® that has given the power to the people so they can use LEDs to instantly create, change, and expand the many things you can do with colorful, durable, bright lights (check out the "Chromacore Technology" section of this Quick View flash movie to learn more). Moreover, LEDs are becoming the preferred substitutes for incandescent lamps because they have comparable brightness, higher level of control, use less power, and run cooler. They also last years longer, normally outlasting the products they are components are in. Put simply, LEDs are the future of lighting.