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Archive for February, 2011

Metal-organic Precursors and Other LED Materials

28 Feb

Like sapphire wafers and phosphors, metal-organic precursors are essential materials for the LED manufacturing process.

Look inside a typical high-brightness white LED package and you’ll find plenty of interesting materials. These might include silicone, various plastics, copper, aluminum, thermal greases, and lots more besides. Look closer and you’ll find an LED chip containing elements such as nitrogen, aluminum, gallium and indium, sitting on top of a substrate that might be made of sapphire, silicon or a suitable metal. Arguably the most exotic materials are found in the phosphors, which might contain “rare-earth” elements such as yttrium, cerium and europium, among many others.

In this article, we looked at two critical materials in the LED manufacturing supply chain, namely sapphire wafers (used as the starting template for most LED chip growth) and phosphors, a group of different materials that are used to create white LED light.

Metal-organic (MO) precursors

Metal-organic (MO) chemicals or precursors are used in the epitaxial growth of LED semiconductor materials to provide metals such as gallium (Ga), indium (In) and aluminum (Al) to the growing layers (see “Epitaxial growth” section – below).

Trimethyl gallium (TMG) is most in demand, not only for growth of most types of LEDs but also for many other compound-semiconductor devices including gallium arsenide (GaAs) electronic devices, and DVD and Blu-ray laser diodes.

During 2010, in the face of growing demand from the LED market, several major MO suppliers took steps to increase their production capacity (see “MO suppliers address demand” section – below).

Joe Reiser, Dow Electronic Materials’ global business director for Metalorganic Technologies, told us that, for the LED market as a whole, backlighting applications took off more rapidly than expected last year. This meant there was “some tightness in the market” in terms of MO supply, he said.

This situation resulted in the capacity-expansion announcements by various suppliers. However, said Reiser, “Dow’s plans were already in place before our formal announcements were made.”

In Reiser’s opinion, the tightness should resolve itself in the next couple of quarters. He explained that Dow keeps a close eye on the market for LEDs, particularly in backlighting and lighting applications, so that it can address the market demand looking several years ahead.

While Reiser was not free to discuss specifics related to pricing, it’s clear that prices have risen during the last year, as a consequence of the supply tightness. However, there have not been any significant price spikes.

When considering starting materials, MO suppliers are primarily concerned with the price and availability of Ga and In, while Al is much more widely available. Reiser said that Dow has contacted its key suppliers of these materials, and feels the company is in a “pretty good position” with substantial agreements in place. Of course, Dow is a very large, global company that enjoys substantial leverage with its suppliers.

Epitaxial growth

Epitaxy is the process of depositing a high-quality crystalline layer of material onto a crystalline substrate. In the fabrication of LED chips, epitaxy takes place inside a metal-organic chemical vapor deposition (MOCVD) system or reactor. For LEDs based on gallium nitride (GaN), the substrate is usually sapphire, and multiple layers are grown to create the specific LED structure.

Metal-organic (MO) chemicals or precursors provide the source of metallic elements such as gallium (Ga), indium (In) and aluminum (Al). In trimethyl gallium (TMG), for example, the metal Ga is attached to methyl groups (the “organic” part). In the MOCVD reactor, TMG breaks apart and Ga is supplied to the semiconductor layer growing on top of the heated substrate wafer. To grow GaN, nitrogen is also required, and this typically comes from ammonia. Other elements called dopants are also introduced to influence the current-carrying ability of different layers, creating either p- or n-type material.

All the materials introduced into the MOCVD system – MO precursors, dopants, ammonia, As and P sources (for GaAs-based LEDs), and hydrogen carrier gas – must be supplied with high purity, to prevent impurities being incorporated into the epitaxial LED layers, which would then affect the performance of the processed LED chips.

 

Philips Lumileds Leads LED Lighting Industry to Freedom from Binning

28 Feb

New advances simplify LUXEON solution development and mark the beginning of the end of color bin charts for white LEDs

Philips Lumileds announced an industry breakthrough today that will relieve luminaire manufacturers’ and lighting designers’ concerns over white light consistency and uniformity and will dramatically simplify the design process for LED solutions. With Philips Lumileds vision for Freedom From Binning, white LUXEON emitters will be so uniform and consistent that there will be no color bin selections. Buyers of the new LEDs, initially released at CCTs of 2700K and 3000K with others to follow, will receive LUXEON LEDs that are already tested and binned at real-world operating conditions so that their performance for color, light output, and efficacy are already known. Lumileds will proliferate Freedom From Binning through new product introductions this year and into the future.

“At random, I can lay a thousand of these new LUXEONs in a straight line and the consistency and color quality from LED to LED will be as good or better as what you would see with many of the bulbs in use today,” said Michael Holt, CEO of Philips Lumileds. “The lighting industry has yearned for quality of light, simplicity of design, and more efficient light sources in mass quantities and reasonable costs that enable solutions that improve on what’s possible with conventional lamps. By combining our unique TFFC and Lumiramic phosphor technologies with new manufacturing capabilities that allow us to ‘hot’ test and color bin, Philips Lumileds’ Freedom From Binning is charting a new course for the LED manufacturing industry to follow and moving us ever closer to the lighting industry.”

The lighting community will want to look at LED performance information in a new way as a result of these advancements. Although typical datasheets present data for LEDs at 25°C, it’s well know that the actual operating temperature is closer to 85°C (sometimes higher) and that the performance numbers reported are essentially overstated. LUXEON products that offer Freedom From Binning are tested at 85°C so that the actual color point and performance numbers are known. “We sacrifice the marketing value of higher lumen and efficacy numbers for accuracy and confidence,” said Holt. “We can calculate performance at lower temperatures but that would defeat the point and potentially mislead.” Most datasheets from LED manufacturers include the information required to understand performance at elevated temperatures and the industry is able to make real-world comparisons between products.

Philips Lumileds will release its first product to feature Freedom From Binning this week at Strategies in Light. Color selections will consist simply of a CCT designation, centered on the black body curve at hot (real-world) conditions. As new LUXEON products are introduced for the lighting industry, Philips Lumileds will expand its Freedom From Binning program.

 

Benefits of LED Lighting

28 Feb

LED lighting systems use up to 90% less electricity than standard lighting products. It is the most cost effective and energy efficient lighting on the market.
home lighting

The benefits of LEDs are:

High Efficiency: These products direct the light in a very specific way, ensuring there is no wasted light onto ceilings and walls where it is not required.
Extremely Vibration Resistant and Robust: LEDs are a solid state device which means the light component is encapsulated within a resin substance. Because of this, they can withstand extreme vibration when they are in use, unlike filament lamps that when heated, become extremely vulnerable to damage if shaken.
Long Lamp Life: Due to the inherent nature of LED lighting products, they have a lamp life of around 50,000 hours. This is 20 times the life span of an incandescent lamp, 12 times the life span of a halogen lamp and 3 times the life span of fluorescent lamp.
Low Power Consumption: LED’s are a very energy efficient lighting option because they utilize the input power more efficiently to generate light rather than light created by heat. This allows LED lighting products to produce a much higher lumen output per watt.
Low Maintenance and Lamp Replacement: As LED lighting products have a long life span there is little need to replace them as often, therefore saving on maintenance costs.
Reduced Carbon Footprint: LED Lights consume up to 90% less power than other lighting methods. This has a significantly positive effect on carbon emissions, helping to make a more sustainable future for generations to come.
Low Heat Generation: Standard lighting products generate a substantial heat, usually around 200 degrees C, making it a dangerous option when used around flammable materials, which is why fires caused by halogen down lights in homes are not uncommon. LED lights generate very little heat; therefore the risk of fire is virtually nonexistent. In fact, you can comfortably hold your hand on an LED fitting, even after it has been running for several hours. Try doing that with a halogen lamp even after 1 minute!!!
Environmentally Safe: LED lights contain no harmful substances such as Mercury, which is found in all fluorescent lamp products, therefore making it the safer option for your family and our environment.

 

Light Up Your Lovely Home With LED Outdoor Holiday Lights

19 Feb

Once again, it is approaching closer to the coming Christmas holiday season, hence one can begin to plan for one’s home decoration now. Everyone will definitely love the idea of beautifying during this festive period and the experience of doing up for Christmas can be enjoyable for the entire family as well.

The most impressive, dependable, as well as energy-efficient types of lights to utilize is commercial LED Christmas lights. These lights can be sturdy, energy saving, and reliable in performance-wise.

A lot of people who furnish outdoors for Christmas time will at the least beautify the awnings and eaves of their homes. One can choose from huge varieties of Christmas outdoor lighting and the most popular choice is usually LED light bulbs.

Single lighted strands which are easily available in one color, multi-colored and even all white are the most well-known in being used for decorating one’s home. The other lighting style which had gotten popular in recent years for home decoration is icicle lighting. Icicle lighting is available with green or white cable as well as with both solid and multi-colored LED light bulbs.

Trees and shrubs are wonderful areas for Christmas outdoor lighting to be utilized and LED lighting is ideal for this task. These lights performed well, looked excellent in deco and safe to use as they don’t get heated easily and thus create fires. By decorating the trees and bushes in one’s home with LED lights will certainly make your home appear very festive, holiday-like and cheerful, and easily noticeable from a distance as well.

Another superb kind of light that is ideal for tree and plants deco, and it covers the top and front part of bushes squarely in a grid, is what most people call net lighting. One can easily handle these commercial LED Christmas lights with ease and speed.

One or two other areas on your residence which you may be considering decorating with Christmas outdoor lighting using LED lights is the yard, shrub, tree and also floral beds, as well as the drive way of your property. To get these trees and shrubs really outstanding and looking prominent in one’s home, LED lights can be deployed around the edges of these trees, flower beds and shrubs.

Another fantastic idea will be to use LED Christmas lights to outline one’s lawn and driveway. The lighting will contribute to the whole idea of Christmas deco and of course connect the whole residence to the theme and create a three-dimensional feel to the driveway.

There are lots of various other great Christmas outdoor lighting goods that you may think about using to beautify your property for the holiday seasons. The deco products can consist of stand-alone frame types which utilize LED lights for the outlines. Candy walking stick lighting is an excellent demonstration of this and can easily be employed to shape your drive way and pathways.

 

LED Lighting: An Illuminating Investment

19 Feb

LED Lighting: An Illuminating Investment

When considering LED lighting solutions for jewelry display cases, art gallery lighting or even museum displays, people love the way high-quality LED lights look, as well as their ecological benefits—but they may be put off by the higher initial cost.

The truth is that LED lighting is a money-saving investment over time. By installing LED lighting in display cases, on countertops and as overhead lights, you’ll save money over the next several years:

LED Lighting Lasts Longer
LED lamps last much longer than traditional lighting bulbs. In fact, they have an extra-long life of over 30,000-40,000 continuous hours—that’s about 6-8 years under normal usage conditions! You save big by not having to replace bulbs or lamps as often.

LED Lighting is Cooler
LED lights give off virtually no heat—which means you spend less on air conditioning to keep your store cool.

LED Lighting Uses Less Electricity
LED lighting solutions use just 3% of the electricity of regular halogen bulbs—just 3%! Imagine the difference that would make on your utility bill for running a store full of LED lights compared to your traditional lighting methods.

So don’t put off investing in LED lights. They show off your merchandise with true white, natural daylight-quality light. And their money saving benefits will more than pay off in the long run!

 
 
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