Melani Warod

LED (two shiny aurora) Applied can say ubiquitous. As a kind of semi-conductive luminescent material, compare with other luminescent material, LED makes other luminescent material overshadowed with its green, high-efficient, reliable, longeval advantage. With the constant reducing of high-power LED cost, it becomes possible to substitute the traditional lamps and lanterns progressively. The application of LED light source in road lighting has already become the focus of the semi-conductive lighting trade in recent years, LED device products are applied to the street lamp, what special requirements are there on technology? What advantages does LED street lamp have compared with ordinary street lamp at present? What deficiency exist? How to solve? Expert has offered from different sides the industry to explain.

It is to popularize popularizing the effective means to make the national standard

Semiconductor chief Li the Jin Dynasty Fujian of Chinese Academy of Sciences

LED mainly has the following advantages or characteristics as the street lamp: Shiny and high in efficiency, the reflection loss of the lamps and lanterns is low, saves energy 70%; Cooperate with the numerically controlled luminance function, electric-saving; Not needing high pressure, the safety is high; Cooperate with the software by the luminance of long-range automatic remote control; Accident, foggy, rainy day,etc. offer extra-high luminance and high lighting source of colour rendering in special circumstances; Install and safeguard simply and conveniently; The module is installed, does not have surplus conductor arrangement; Will not cause the light pollution or waste; Long life, mean not needing to change frequently, thus reduce the interrupted potentiality of the traffic, have reduced to this maintenance cost paid. Someone has calculated, adopt LED street lamp except in cost of single light and fabrication cost installed at first than the elevation of light of high-pressure sodium, superior to the high pressure sodium lamp greatly in laying the cost, power consumptive cost and life-span.

The main technical matter that LED street lamp faces is: Output power, luminous flux, two-shot optics design, distributing thermal design and power system design. The improvement of output power and luminous flux also needs further promoting from basic levels such as the epitaxy technology of the white light LED of high-power, chip technology,etc.. In two-shot optics design, there are Lambert types, side shot type, bat's wing section and gathering several kinds of light shape in radiation forms of LED. In the field of road lighting, according to the design experience Lambert type and bat's wing section is more applicable, through two-shot optics design, make illumination range, curve of luminosity of LED accord with the demand for road lighting. It is one of the problems that LED street lamp needs solving to dispel the heat especially, because the luminance of LED street lamp is expected much, the calorific power is large, and the open air, this kind of environment for use, is more harsh, if it will not cause LED to wear out fast directly well to dispel the heat, stability is reduced, except it is good to need heat abstraction of power type LED itself, because lamps and lanterns have a characteristic used at night in the open air on the road, it helps the natural convection of air to dispel the heat on the side that the heat-dispersing surface lies. The power system of LED street lamp is different from traditional light source too, the cooperation between low energy consumption of LED, low working voltage and low output power, low output voltage of the solar battery assembly is very suitable, how make close compression a series of LED together work, investigate the intersection of LED and an index of street lamp too safe, reliable.

Synthesizing the above can find out analysis in market prospect and technical matter of LED street lamp, the factor influencing its application is: First, the great of fabrication cost of LED street lamp, is unfavorable to popularizing. Though has solved the heat-dissipating problem of LED street lamp tentatively at present, will still hinder the popularization of LED street lamp to exceed high price and overweight lamp holder.

Second, the modularized reliability of LED street lamp still needs to strengthen, because of driving circuit, etc. will cause the failing of LED street lamp too.

Third, both simple point and many LED street lamp of pointolite have difficult problems of dispelling the heat. A street lamp to adopt 250W high pressure sodium lamp, because technology is relatively ripe, break up and thermally control very well, even work for 5000 hours, it is still minor that only decline, luminescent efficiency can also be more than 70%. With present technology, the high-power LED street lamp under the same condition, because the heat-dissipating problem is difficult to solve, only decline bigger, luminescent efficiency will drop to 30%. If want to improve the lamplight effect by strengthening the electric current method of the voltage, it is very apt to cause the phenomenon of LED chip damage.

Fourth, LED street lamp range is short, so LED street lamp also needs further strengthening research how to make the work at the great height. In addition, it is to popularize popularizing very effective means of LED street lamp to make the national LED road illumination standard.

Influenced and employed the key factor to dispel the heat and reliability is

Steady moist photoelectric Vice President of Co., Ltd. Chen HeSheng in Jiangsu

LED light source has two kinds of methods, one uses traditional low-powered LED to make up, generally reaches more than one hundred even several hundred, the power design is complicated. Another kind uses the large power tube to function as the light source, the price is more expensive. Two method want scattered thermal design and service dependablility as design the consideration mainly inevitably, China apply to government's demonstrative project more, there are few projects of really market-based operation, there are more application embodiments in this respect abroad, but the shortcoming of its maximum is still reliability, light output lumen counted and price, a lot of project inferior in quality because of LED, as demonstrate the intersection of life-span and long advantage well. In addition, from cost, market / the intersection of W- and stage of 80lm/W, theory luminescent efficiency its can reach 300lm/W about, so there is very large development space technically. The semi-conductive light source street lamp is at the initial stage for development of industry at present at the same time, there are very large promotion spaces in raising radiation effection, drive control system optimization, light distribution and designing, a large amount of need of work of research and development is launched thoroughly.

A LED street lamp needs 1W white light LED about 100 drops on average at present, calculate with 3 million annual street lamp demands in the whole country, the demand for white light high-power LED will reach 300 million every year.

It is unable to popularize in an all-round way that the standard specification is deficient

Optical photoelectric tube photoelectric device branch's general secretary Peng WanHua of employer's organization in China

Because LED street lamp has two outstanding advantages: Energy-conservation (it is reported but above the festival electric energy 50%) , long life (can be reduced and maintained and lengthen and change time) ,So the development, application of Chinese relevant LED street lamps is developed quickly at present. A lot of large and medium cities are trying out LED street lamp, but not adopted in enormous quantities in some roads.

The subject problem at present of LED street lamp does not have standard specification, unable to popularize in an all-round way, LED several specifications used for street lamp, for instance among them: Colour temperature, colour rendering (colour rendering index) And the glare,etc. has not been fixed yet.

In addition, the price of LED street lamp is too high, according to different power and installation height at present, price of it is at 3000 yuans -5000 yuans /only, it have difficulty in for to popularize and apply large-area.

The urban management system of the street lamp is that the bull is responsible for, this popularizes and applies and brings very great difficulty to LED street lamp.

Proposing the relevant department as soon as possible, the organization makes the relevant standard of LED street lamp and sets up relevant detection mechanism.

The street lamp design criteria which Ministry of Construction makes newly " The road lighting design criteria in the city " (CJJ45-2006) Begin to carry out on July 1, 2007, among them not mention to use the question of LED street lamp. Here, the relevant department should organize the relevant personnel to discuss to further improve conscientiously and technical and complete day by day, there is development quickly. Consider nearly there are this broad market of 200 million street lamps in China, ought to especially pay attention to, in addition, the existing part of enterprise products are exported, the market prospect has a good prospect, will employ the market to start on a large scale in 2010.

The products belong to initialization stage at present, very different, the subject problem is that the heat-dissipating problem is not solved well, not only luminescent efficiency drops, but also it is relatively serious to only decline the problem, even fail. The related departments should pay close attention to standard formulation, need to decline the test all before being dispatched from the factory, reduce the intersection of lamps and lanterns and thermal resistance, fill, disperse hot, accomplish high-efficient, long life really, so as to cultivation and sound development of market.

LED replaces high pressure sodium lamp energy-conservation 40%

Sharp executive vice president Chris James of company's market of the department

The characteristic of LED has already exceeded the fluorescent lamp generally adopted now, can predict, LED lighting engineering be entered in many kinds of environments. Besides energy-conservation, the life time of the LED lamp is much longer than the traditional bulb, and does not adopt harmful substances such as common mercury, mercury, lead,etc. in ordinary bulb, the LED lamp wants environmental protection.

Take action in illumination of LED city (LED City community) Start in February of 2007, pursue the illumination of garage parking in Raleigh of N.C. State and try the project, get Cree (department sharp) , the support of Lighting Science Group, AmTech Lighting Services and Progress Energy. The goal of this community is to impel each city to strengthen cooperation and raise the efficiency while disposing energy-conservation to light, in order to achieve the goal of saving the cost and in environment protecting mode as soon as possible. It is to replace high-pressure sodium lamps and lanterns with LED lamps and lanterns that this tries the project, according to the assessment by Progress Energy, the energy-conserving result is up to 40%.

It aims at meeting the local demand to take action in illumination of LED city. Toronto from Texas of U.S.A. to Canada, LED illumination already been succeeded in disposing in the whole North America area, each demonstration area for bring huge energy conservation while being local, and meet its economic demand. For example, there are 125,000 Michigan state A kindness A Poul market that Michigan university locates, this city installs more than 1000 LED street lamps recently. This in a seemingly unattractive number in China, but have a great meaning for city of U.S.A. like Poul city such scale of A of A's kindness. Each consumption and 56 watts of LED lamps is all right in continuous duty 10, come to replace 120 watts of consumption and life time has the bulb for two years only, this makes public illumination energy consumption of A kindness A Poul market reduced by half, the annual greenhouse effect gas is discharged and reduced by 2425 tons, this is equivalent to the exhaust quantity discharged in one year that 400 cars set out on a journey.

The sharp company of the department is with the help of LED City cooperative partners such as Tianjin economic and technological development zone,etc., promote this transition together as the advocate whom a new generation lighted. Employ energy-concerving and environment-protective LED technology to help to solve the difficult problem of the energy shortage of the world, it is the most valid energy-conservation which we can adopt so far that moves.