LED was one of the greatest Invention in 20 Century, where Incandescent light bulb was no question one of great inventions in 19 Century. It may be time to ban Edison's venerable, now vilified, light bulb. European leaders, green pundits and the widely reported light bulb provisions of the U.S. Energy Independence and Security Act of 2007 all urgently push the abandonment of incandescent bulbs. People started collect 100W incandescent light bulb as after another 20 years, the youngster may not understand what Light bulb was. As those young blokes under 25 years ago may not see what Vinyl LP is although this is still the best format for music and audio reproduction in term of high fidelity in this world of technology. As in the Hi end Audio market 20% of the player has his own LP equipment and 40% with vacuum Tubes amplifier which almost went extinct in 1986. Incandescent light bulbs will not the same case as Vinyl as its intrinsic low efficacy will kill itself.
Semiconductor light emitting diodes (LEDs) are finally on the verge of having the capability to radically alter the entire lighting landscape with staggering improvements in both lighting efficiency and efficacy. The high-power LED emerges directly from the same semiconductor, digital infrastructure and intellectual property that brought us iPhones, laptops, hybrid cars, PSP, Xboxes, Net book and LED Back light LCD TV. Though the word "Revolution" has been devalued by overuse, quite irony, the LED is probably only the third revolution in illumination technology since the invention of fire at Stone Age. Until now, there have been only three illumination technologies: fire, from first rubbing stick to produce, torches, tallow and wax candles and, later, whale oil lamps; kerosene lamp, electric incandescence, famously perfected in 1879.
About 12 billion electric lights use Edison bulbs; one third is in the U.S. So, lighting up the world consumes about 2 trillion kilowatt-hours annually. This is in fact equivalent of nearly a billion tons of coal annually. In the U.S., half of that is in fact coal. U.S. lighting uses the equivalent of 50% of the energy used by all cars on American roads.
In Hong Kong, Electricity Bill domestic illuminations accounts 22%, Air Con for 34%, fridge for 14%, and TV take as much as 7.3% of total monthly electricity bill amount. Over the year, there is practical no raise of electricity fare. The cost of illumination has almost collapsed. It is 1,000 times cheaper to light up a room today than at the beginning of the 1910’s, and 10,000 times cheaper than in 1850. Consequently, appetites have soared for the central product of illumination technology, lumens. Humans consume 40,000 trillion lumen-hours per year.
LEDs are fabricated from various concoctions of "compound" semiconductors, mainly gallium and indium. All older forms of illumination use brute force to heat something till it glows. The central difference with an LED is that photons are emitted by designing exquisitely precise semiconductor junctions, tuned just so to employ efficient quantum phenomena that emits photons. It's the quantum equivalent of using butane lighter instead of rubbing sticks to start a fire.
Commercial LEDs were quickly introduced by 1968 after Nick Holonyak, a GE engineer nvented it in 1962. Early ones dribbled out pathetically small flows of lumens and were ridiculously inefficient, converting fewer watts to lumens than even the notoriously inefficient incandescent bulb. The tiny, solid, robust and very long-lived LED was ideal for instrument and indicator lights, cockpit of an aircraft and my expensive Boluva LED digital watches. Price of a 2nd hand Toyota car in 1978.
Over the years, scientists and wafer epitaxial engineers rapidly developed the machinery of photonic semiconductors, suitable manufacturing process and better selection of material. Today's LEDs are 1,200 times more efficient than they were in 1968. LEDs have followed called Haitz's Law, named after the LED researcher Roland Haitz. The law says LED brightness doubles every 18 to 24 months.
Currently, LEDs have already achieved 100 lumens per watt, Incandescent bulbs yield some 15 lumens a watt, CFLs about 80. Without considering the cost impact, in fact, LED is the time for replacing all illumination world wide!
Applications for LEDs have followed their rising power and declining cost, from instrument displays in the early days, to traffic signals and automobile brake lights and interiors, to back-lighting mobile phones and LCD screens, signature decorations. The very first few Blue 5mm LED Vertical lamp was selling at USD50.00 a piece and how is about USD0.2 in the retail electronics shops.
Annual global sales of high-brightness LEDs already total $5.5 billion with 400 million on Illuminations, even before invading the 40,000 tera-lumen market for general illumination. General illumination is currently supplied about equally by incandescent bulbs (dominant in residential markets) and fluorescents (dominant in commercial buildings).
With the lumen power in hand and costs declining, there is one last hurdle for LEDs to overcome in order to conquer general illumination. The reason most people have resisted and will resist using CFLs, and that also currently impedes LED adoption (particularly for indoor lighting) is the quality of the light. CFLs must achieve the light quality of incandescence to enjoy wider adoption.
All lumens are no more equal than all calories are. The eye, like the palate, is exquisitely sensitive to quality. 500 hundred calories at beef doesn't taste the same as 500-calorie foie gras. 500 lumens from a CFL is visually harsh and makes food and people look unnatural, compared with the same 1,000 from Edison's incandescence.
Optical scientists cleverly named the visible mix rendered by the colors in light the Color Rendering Index. The CRI gold standard is numerically 100, the color of pleasing Edison incandescence. A CRI below 90 is noticeably nasty to the eye. CFLs produce and are essentially stuck.
But LED lights have been inching up the CRI curve. LED Lighting Fixtures, for example, just started selling a 12-watt product with a pleasing 92 CRI that looks like a standard 60-watt indoor floodlight and uses 50% less energy than a CFL.
Longer life time 100,000 hours for better cost obvert the years of the life time, small and robust, can be used on various compact and dynamic application such as automobile aircraft, electronic controllable intensity and colour variation, faster response for display such as Back light unit for LCD TV, automobile front lamp for Safety concern.
CFLs contain tiny amounts of mercury. Individually not much, but billions add up, and no one really believes recycling will keep all that mercury out of landfills.
Obama is promoting the green source of energy, does not man he does not has the point, as all kind of wars after the Vietnam is mostly related to oil resources A clever move would be invest more GPD into the greener energy production rather than on the military expensive. That may have a better return., and human will rely les sin the oil which would be the major income in the Middle East. Thought its is easy to say but hard to make it materialization, as when less people buy oil, they will automatically reduce the oil price and if the oil price drops to certain level, that will have leverage effect on running for new greener energy sources.
Any way, only national decision for long term could bring LED into real substitutes for CFL and incandescent lamps. When I bought my first Motorola star TAC hand phone in 1990, it was almost $2,000, no one who imagine that the kind of hand phone will eventually easier to buy one and much faster to expand his user network than the traditional land line in 10 years time.
Every says the LED cost if high, and from all history of electronics life cycle, the LED ASP is dropping as an average of 12% with volume of 20% more producing each year, and the ASP drop is more eminent over the last three years. We will see after 2012, an High-power LED will be just 20% of Today’s.
As we can see that the technology will bring down the price, three years ago the most extensively used Die bonder AD830 in LED industry was running at 10,000 an hour, and now the new die bonder is running at 18,000 unit a hour for the same type of package under same process. I should say the LED equipment supplier would be one of major contribution to lower the ASP of the LEDs.
The Above table is measured with a driving current of 350mA. The latest announcement from Cree is 161 Lm/watt which is the most powerful LED so far.
