LED is 50 years old

The LED As We Know It Is 50 Years Old Today. In 1962, 50 years ago today, Nick Holonyak Jr. and his team at GE invented the Light Emitting Diode. While LED lights are almost everywhere today, their initial development was ripe with uncertainty and competitive research. A direct result of another groundbreaking technology of its day, the laser, LEDs have continued to evolve and now illuminate our homes and transmit our data.

In the early 1960s, LEDs were only capable of emitting infrared light. Nick Holonyak suggested using a mixture of gallium arsenide and gallium phosphide to create one that could produce visible light, but was shot down by his non-believing colleagues. Undeterred, he gave it a try and fortunately it worked: the LED as we know it today was born. Wednesday, October 10, 2012: Fifty years ago today, 33-year-old GE scientist Dr. Nick Holonyak, Jr., invented the first practical visible-spectrum light-emitting diode (LED).

50 Years of LED Technology article tells that Nick Holonyak was sure the LED would replace the incandescent light bulb when he presented it to GE executives 50 years ago. While the incandescent is still king in homes across the nation, the LED has transformed lighting in more ways than Holonyak could have imagined.

Wired Design caught up with Holonyak, now a professor at the University of Illinois, to ask him about the history, and future, of LEDs and published the material in How Lasers Inspired the Inventor of the LED article.

“Learn more. Do more. Build more. Reveal more.”


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  2. Tomi Engdahl says:

    World+Dog hails 50th birthday of the LED
    But this now commonplace technology is much, much older

    It’s certainly 50 years since Nick Holonyak, working at GEC’s Syracuse, New York facility, developed what is considered the first LED capable of generating visible light. Holonyak’s LED was also the first to be in form ready for commercial usage.

    He wrote up his work and sent it off to Applied Physics Letters on 17 October 1962. The journal published the work in December 1962 under the headline ‘Coherent (visible) Light Emission from GaAs xPx Junctions’.

    However, Holonyak’s work followed that of Gary Pittman and Robert Baird who, in 1961, observed the emission of infrared light by Gallium Arsenide

    Indeed, while Holonyak was working on his visible LED, so too were Robert Hall, also of GEC but employed at a different location; IBM’s Marshall Nathan; and MIT’s Robert Rediker. All four sent papers to journals; Holonyak was judged by his peers to have produced his LED first.

    Follow the literature back and you end up in Britain in February 1907, with the work of Marconi assistant Henry Round, who first observed the emission of light from a crystal of silicon carbide when a current was applied to it, a phenomenon called electroluminescence. In that sense, the LED is more than 100 years old. Round, however, never wrote a report on his findings.

    Twenty years later, Russian Oleg Vladimirovich Losev became the first scientist to create a semiconductor diode capable of emitting light – the first LED. Losev’s write-up was published at home, and in Britain and Germany

    In 1927 Losev applied for a patent to protect his finding, and the IP was granted in December 1929.

  3. Tomi Engdahl says:

    LED Lighting–Top 10 benefits

    While LED lighting has been known to consume less energy and have a long lifetime for greater energy and maintenance savings than incumbent technologies, there is much more to this solid-state lighting technology. LED lighting was originally used for indicator lights on various electronic devices but through the years, this technology has penetrated into numerous industries. Here are the top 10 benefits of LED lighting that made this possible.

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  5. Tomi Engdahl says:

    LED lamp is powered by nothing but gravity
    Conceptual device meant to provide poor with alternative to kerosene lamps

    simply put, it’s an LED lamp that runs off of nothing but gravity.

    On their Indiegogo page, the two note that in the world today there are more than a billion and a half people with no access to a reliable electricity source. When it becomes dark, the most popular form of light comes from kerosene lamps. This is a problem for a number of reasons

    The lamp is considerably simple to operate — a cable hangs from a gear holding a plastic bag filled with dirt or rocks and the energy produced from the bag being pulled down is enough to power an LED bulb for up to a half-hour.

    The GravityLight is expected to sell for $10 when it hits shelves. Once things are ramped up, the cost will likely drop to $5.

  6. Tomi Engdahl says:

    World’s first warm white LED to use single phosphor with single emitting center
    Breakthrough could lead to widespread use of LEDs for indoor lighting

    University of Georgia researchers have published a report that details the fabrication of the world’s first light emitting diode (LED) to emit a warm white light using a single light emitting material (phosphor) with a single emitting center for illumination.

    “Right now, white LEDs are mainly used in flashlights and in automotive lamps, but they give off a bluish, cool light that people tend to dislike, especially in indoor lighting,” said senior author Zhengwei Pan, an associate professor in the department of physics in the UGA Franklin College of Arts and Sciences and in the College of Engineering. “Our material achieves a warm color temperature while at the same time giving highly accurate color rendition, which is something no single-phosphor-converted LED has ever been shown to do.”

    In a majority of today’s LED bulbs, warm white light is achieved by using a blue LED chip coated with phosphors to create what’s aptly referred to as phosphor-based white LEDs.

    Pan and his UGA team created a new phosphor that combined minute quantities of europium oxide with aluminum oxide, barium oxide, and graphite powders. They then heated these powders at 2,642 F (1,450 C) in a tube furnace. The vacuum of the furnace then pulled the vaporized materials onto a substrate, at which point they were deposited as a yellow luminescent compound in a bulb and illuminated by a blue LED chip.

    The result: warm white light.

  7. Tomi Engdahl says:

    LED lighting industry analysis and market forecast

    In recent years, ‘Low-carbon Green Growth’ has emerged as a very important issue.

    LED is the trend to newly lead the optical industry, which is one of the world’s most energy-intensive sectors. In addition, it has been becoming the most important axis of ‘Low-carbon Green Growth’ industry due to its high-energy efficiency and long life, and has been diversely expanding its application field to electricity/electronics/lighting, and so forth as the key industry of green contents that IT technology and semiconductor technology are integrated.

    In particular, since LED lighting not only has large energy-saving effect but also is an environmentally friendly industry, the expectations for industry productivity and job creation are very large.

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  9. Tomi Engdahl says:

    LED research and where’s the money?

    Nothing highlights growth potential more than evidence of investments. So what does the industry look like from a growth perspective? It just takes a glance at the number of research reports flooding the market to see that expectations are blossoming.

    UV LEDs According to Yole Developpement’s new report UV LEDS:
    The report cites the compact size, low cost of ownership, and environmentally friendly composition of UV LEDs for their potential to continue to replace such incumbent technologies as mercury. Expectations are, according to the research, that this segment will grow from $45M in 2012 to $270M in 2017, a CAGR of 43%, compared with a CAGR of 10% for traditional UV lamps over the same period.

    Looking at several individual applications, LED-based street lighting is expected to surpass $2 billion by 2020 says Pike Research in its recent Smart Street Lighting report.

    While all smart street lighting projects are in pilot phase, it’s the existing ownership models and tariff structures in the U.S., Europe and Asia that are holding back faster adoption. If utility companies own the streetlight systems and charge a fixed tariff per light, there’s little incentive to upgrade. Now, with prices finally coming down and the long life of LEDs assured, the benefits are beginning to outweigh the barriers.

    The LED-flexible display screen business is also booming. While the market is in its infancy, the first products are expected to come out at the end of 2013, and flourish over the next five years.

    Frost & Sullivan weighed in with its research report: Analysis of the North American LED Lighting Market. The report finds that the market earned revenue of $1.15 billion in 2012 and expectations are that it will reach $3.63 billion in 2017.

  10. Tomi Engdahl says:

    Five Brilliant LED Inventions for Everyday Use
    Stunning and useful ways to use LEDs

    Energy efficient and long lived, LEDs can be used for hundreds, if not thousands, of important purposes. On the lighter side, these convenient little lights have been the center of many illuminated projects, from glow-in-the-dark umbrellas to color-changing, temperature-controlled shower heads. Browse through the list below to learn about some of the most dazzling LED ideas that can brighten up your day.

  11. Tomi Engdahl says:

    OLED vs LED lighting: Is there room for OLED lighting?

    IDTechEx Research finds that in its “most likely” forecasts scenario OLED lighting will become a $1.3 billion market by 2023 – equat to 1.3% of the market size of LED lighting at that time.

    OLED displays are growing quickly but their lighting counterparts are still actively trying to define their unique selling points vis-à-vis LED lighting. Today, they lag behind in terms of efficiency. This is because LEDs regularly offer 90-100 lm/W at package level (the LED chip encapsulated), while OLED modules are still in the region of 20 to 50-lm/W. The lifetime of LEDs far exceed that of OLEDs. Indeed, LED lamps regularly offer in excess of 50,000 hours, which is why they initially found a niche market in out-of-reach outdoor applications. In contrast, OLED lighting offers 5,000 to 15,000 hours of operational life even when encapsulated.

    LED lighting is also now low cost, selling at $5/klm at package level (luminaires costs $20 to $100/klm). Contrast this with the extortionate price of OLED today. They cost $300 to $500/klm at panel level, excluding the cost of fixture design, retail, installation and profit margins

    Based on our “most likely” scenario, IDTechEx forecast the market will grow to $1.3 billion in 2023 and initially grow at a rapid rate of 40 to 50% annually, although the initial market base in very small

  12. Tomi Engdahl says:

    True or false? High-power LEDs don’t generate IR heat in the forward direction like a filament lamp

    If one could review the all the lighting industry’s literature of the last 10 years about high power LED lamps and luminaires, would you question this headline? That is, if you read that a high power LED emits no UV or IR and that any heat is created only in the PN junction and then transferred to a heat sink. Okay on the UV part; but the IR part? Read on.

    What you will further seem to know for sure is that the PN junction is the hottest point in an LED (or any other power semiconductor for that matter) with the LED mounting substrate and or heat sink being somewhat cooler.

    You likely agree with what you have just read. Having been involved over several decades with silicon power semiconductor and power LEDs in one way or another I also would have agreed… until I did not.

    Operating the array at only 25 watts (about 30% of maximum, and a fan-cooled heat sink and LED substrate both under 35ºC (meaning the junction was, with 100% certainty, under 40-45ºC), I observed, as I positioned the small remote-phosphor sheet over it, that my hand immediately got too hot. In the past I had never paid much attention to this kind of thing. I put my hand virtually on top of LEDs and almost got burned. How could this be, I asked, if the LED substrate is less than 40ºC.

    I positioned a thermocouple wire across the LEDs and measured over 125ºC!! Again, how could this be? I measured again with non-contact IR meter and got same temperature.

    Virtually identical observations. Operating at less than full power, with substrate below 50°C, the top surfaces of the array were measured at well over 100°C and as high as 150°C. Instrumentation error? Really only 35-40°C? My imagination? A drop of water placed on top of any one of the devices boiled off in seconds. The last I knew, water boiled at 100°C.

    A sliver of paraffin, specified for a 70°C melting point, placed on any one of those surfaces, melts ”immediately”.

    I could, with the royal blue light at 75 watts, turn that little piece of aluminum into a hot plate and, even from 3.5 inches away, bring the water to 56°C while the LED substrate was only at 40°C.

    The black, high-emissivity dot, affixed to a surface which, per all industry conventional wisdom, could not possibly be over 50°C, quickly measured over 200C per the computerized IR image.

    A piece of paper coated on both sides with that same high emissivity material, began to smoke and catch fire in less than a few seconds. Since when does 50°C start a fire?

    Where does this lead us? Contrary to conventional wisdom or, better said, industry awareness, high power LED’s DO generate IR and the heating resulting from such.
    The small percentage of 450 nanometer blue light, generated in the PN junction, is absorbed by the various semi-transparent chip and coating materials before exiting the device. That absorption creates—surprise— some heat.

    What does this mean? It means that if a high power LED arrays is powered to X watts, most of that power, (80-90%) will be manifested as heat in the heat sink. The balance will show up as blue light. But a portion of that will in turn be transformed into heat on the light-emission side, just like a standard old incandescent lamp

    Many papers have been written about the Stokes effect, wherein the process of converting blue light to white, via blue light absorption in a phosphor, causes some heat. But the heating described here has nothing to do with Stokes effect since it occurs whether or not a phosphor is present. The effects described here are not easy to detect in 1-2 watt LEDs since the total top-side heat energy, being only 8-9% of that 1-2 watts is small. In a 5mm, that heat is so little and irrelevant to ever be noticed.

    Now that we know about it, does it even matter? Well it means that when a phosphor coating is deposited right on top of an LED array such as a 100 watt COB, the phosphor must have high temperature inorganic binders rather than low temp epoxy-type organic binders.

    It also means that if the top surface of a high power LED array is too close to a temperature sensitive object (such as chocolate candy in a display case?) bad things could happen.

  13. Tomi Engdahl says:

    Reverse Engineering a Candle Flicker LED

    Candle flicker LEDs are a one part replacement for a real candle. They contain both a yellow LED and a control chip that modulates the light to create a candle effect. [Cpldcpu] took a deep look into reverse engineering one of these LEDs.

    To analyze the circuit, which is potted into the LED itself, a shunt sense resistor was connected to the LED. By connecting this resistor to a logic analyzer, the control signal could be observed.

  14. Tomi Engdahl says:

    LED Industry Innovations: 6 Trends to Follow

    This is Haitz’s Law, and it states that in every decade, the cost per lumen (unit of useful light emitted) falls by a factor of 10, and the amount of light generated per LED package increases by a factor of 20 for a given wavelength of light.

    Fluorescents typically run in the range from 45 to 75 lm/W. Metal halide achieves up to 115 lm/W and high-pressure sodium up to 150 lm/W. LEDs can theoretically achieve a maximum of between 260 and 300 lm/W.

    Essentially all of the LEDs used in lighting are based on the semiconductor gallium nitride, GaN. This is bonded to a substrate, which in the majority of LEDs today is either sapphire or silicon carbide. Other substrates are under development

  15. Tomi Engdahl says:

    LED lighting were sold last year for $ 1.1 billion dollars.
    According to the NPD Displaysearchin sales will grow to $ 3.4 billion (nearly € 2.5 billion) in 2017.

    The Institute estimates that the standards of 500 x 500 micron LED chips was purchased in 2012 by about 17 billion pieces in various products. This year the number is growing as much as 61 billion chip.

    2014 marks a new era in many ways the beginning of LEDs: use in TVs/monitors starts to decline and at the same time lighting LED sales will reach almost the same level.

    Today’s most popular LED fixture is a fluorescent replacement LED tube because they do not contain mercury, are 50 percent more energy efficient and longer lasting traditional fluorescent tubes.

    Source: Elektroniikkalehti

  16. Tomi Engdahl says:

    Cree pushes through 300-lm/W LED efficacy barrier

    Cree, Inc. claims it is the first company to break 300-lm/W LED efficacy barrier by demonstrating a white, high-power LED with a LED efficacy measured at 303 lumens per watt, at a correlated colour temperature of 5150 K and 350 mA.

  17. Tomi Engdahl says:

    Osram claims world’s most efficient LED lamp

    An Osram research team has claimed to have succeeded in constructing the most efficient LED lamp in the world which achieves an efficiency level of 215 lumens per watt.

    The lamp in tubular form consumes only half the power of current common fluorescent and LED tubes, and also achieves significantly superior colour rendering.

    The device consumes 19W.

  18. Tomi Engdahl says:

    New acid-based manufacturing technique results in brighter, more resilient LEDs
    Researchers develop method to better technology without increasing energy input

    The group coated the semiconductor material gallium nitride with a layer of phosphorus-derived acid while simultaneously applying a self-assembling phosphonic material.

    “By coating polar GaN with a self-assembling layer of phosphonic groups, we were able to increase luminescence without increasing energy input,”

  19. Tomi Engdahl says:

    Newswatch: European LED makers need to act smartly

    Market analysts agree that the traditional lighting market will start to decline from around 2017. By which time LED lighting technologies will account for more than half of the overall lighting market.

    European lighting manufacturers are facing up to almost a ‘Perfect Storm’ in which the looming price war for LED bulbs is set to bite into profits just at the time when a period of low growth is expected as the long-life bulbs become more common.

    “In the residential area, costs are still seen as relatively high,” explained Osram Chief Technology Officer Peter Laier. “You’re also getting a product that lasts at least 10 times longer.”

  20. Tomi Engdahl says:

    Substrate developments drive up LED front-end industry expansion

    The LED front-end manufacturing sector is facing a triple assault that will shape the way the market performs in the future forecasts market intelligence analyst Yole Développement in a new report.

    Increased demand for larger size sapphire wafers with big players, such as LG, Sharp or Osram moving to 6 inch wafers and Taiwanese players moving to 4 inch wafers.
    Increased demand for PSS that has now become mainstream in the industry (87% share as of Q1-2014), even if some questions remain concerning key patent holders’ strategies. Development of GaN-on-Si and GaN-on-GaN LEDs with both technologies having begun mass production in some companies (such as Soraa for GaN, or Toshiba for

    “New LED substrate is one of the key topics impacting the LED front-end industry”,

  21. Tomi Engdahl says:

    See-through OLED display goes eye-interactive

    Dr. Uwe Vogel of the Center for Organic Materials & Electronic Devices Dresden (COMEDD) outlines how a see-through OLED display is going eye-interactive.

  22. Tomi Engdahl says:

    New generation controls offer huge benefits for indoor lighting

    Dr Andy Davies explains how advent of new generation controls offer numerous benefits for indoor lighting applications.

  23. Tomi Engdahl says:

    Are your LEDs electrically overstressed? Part I

    Yankun Fu identifies the transient conditions that are benign to LED components and those that can induce electrical overstress (EOS) and catastrophic failure and suggests some ways to minimize the potential for EOS.

  24. Tomi Engdahl says:

    LED lighting in buildings to pass USD10.3B mark in 2014

    Revenue from the global LED Lighting market for buildings hit $8.1 billion in 2013 and is forecast to rise to about $10.3 billion by the end of 2014 according to market research analyst, Memoori Research.

  25. Tomi Engdahl says:

    YunSun LED

    During the 2014 trip to China, our supplier YunSun was kind enough to pick us up in Shenzhen and give us a tour of their factory.

    YunSun buys their dies from a high quality Taiwanese company.

    Three thin sheets containing 12,000 LEDs soon to be hatched!

    LED wire bonding machine. This attaches a hair-thin gold wire from the top of the LED die to the anode lead.

    One of the first things that surprised me on this tour was that the entire operation was done in open air. For some reason I assumed manipulating silicon dies required clean room technology. I could do this in my basement! Hmm…

    Once the wire bond is in place and the adhesive is cured, the lead frame gets placed in the LED mold and gets epoxy resin pushed in around the lead frames.

  26. Tomi Engdahl says:

    GaN LEDs: Sputtering Cuts Costs on Larger Displays

    A team of University of Tokyo researchers in Japan has developed a technology for creating GaN LEDs on glass substrate, which could not only cut manufacturing costs but also help to develop OLED light panels.

    The researchers use a sputtering method to transcribe the GaN LEDs onto the glass substrate. The team has not yet measured luminous efficiency or external quantum efficiency for any single color but is currently testing the efficiency of the internal quantum at low temperatures.

    InGaN-based light-emitting diodes (LEDs) have been widely accepted as highly efficient light sources capable of replacing incandescent bulbs but applications of InGaN LEDs are limited to small devices because their fabrication process involves expensive epitaxial growth of InGaN by metalorganic vapor phase epitaxy on single-crystal wafers.


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