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:
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.
Cost of Light
The opportunities to replace conventional lighting with LED lighting for general illumination are growing, fueled in part by the continual advancements in LEDs and the global need for energy-efficient lighting alternatives. Performance is an important metric for assessing the viability of replacement by LED sources. These devices that once merely lit calculators and cell phone displays can now illuminate an airport terminal or a 100 foot building façade. They increasingly match or exceed the efficacy of conventional lighting sources, particularly with the advent of today's power LEDs. In fact, the efficacy of LED sources, measured in lumens per watt, is eclipsing that of incandescent and halogen sources.
As a result, Philips Solid-State Lighting Solutions' systems are displacing conventional lighting methods in a number of applications where LEDs were previously thought impractical. And this exciting trend continues. Performance is improving rapidly in the intensely competitive LED supplier field where current data from these manufacturers shows LED performance ahead of forecasted levels, and the cross over point for matching the efficacy of fluorescent sources outpacing the predictions made just a few years ago. Yet performance is only one metric.
Matching the cost of conventional lighting is another critical element for replacement to occur. The true measure of cost goes beyond just the initial cost of the lighting system and incorporates lifetime and operational costs as well. For example, an incandescent source may only have an initial cost of fifty cents, yet its energy consumption will cost more than ten times that over its relatively short life, when a new source must be purchased and the cycle starts again. The metric that accounts for all of these factors is called the Cost of Light. This is the measure that sophisticated customers, such as those managing large buildings, use to compare the true cost of illumination. Intelligent LED lighting systems are intersecting the Cost of Light of incandescent and halogen sources and are rapidly approaching the economic cross over point for fluorescent sources.
These are Philips estimates, and are not indicative of future performance. Decreasing operational and lifetime costs, together with improved LED performance, enable a wide spectrum of new applications.