年份：2012年

Different cooling materials for LED lamps (1)

The commonly used cooling material for electric devices is aluminum. In some special cases, copper is also used, like CPU. Copper better than aluminum in capacity of heat-transmission but worse in capability of heat radiation. Compare two radiators with same construction but made by different materials, radiator made by aluminum are better in natural cooling. However, if cooling fans are taken into account, the result is opposite. Recently, a lot of LED manufacturers tend to introduce ceramic, conductive plastics and graphite material into their LED cooling technique. What are the particular performances of these new cooling materials for LED lamps?

 

The commonly used cooling material for electric devices is aluminum. In some special cases, copper is also used, like CPU. Copper better than aluminum in capacity of heat-transmission but worse in capability of heat radiation.

 

Ceramic: the firstly used cooling material is a type of ceramic with porous structure. The original purpose of this radiator is to raise the coefficient of heat transfer by increasing the surface area. In fact, this method is infeasible. The real thermal conductivity of this radiator is only 15 W/(m oC), even lower than alumina (a commonly use ceramic material for cooling technique). Thermal effect of it is much worse than the aluminum plate. Thus this oldest ceramic cooling material exited for a very short time and disappeared thoroughly.

 

Conductive plastics: this is a new LED Street Light cooling material turned up in recent years. If you study specifications of this material, you will find it has a very low thermal conductivity (only 15 W/(m oC)). Some plastics have better capabilities of surface heat radiation than aluminum. However, tests results indicated that this cooling material is only suitable for low powered LED lamps. They have very similar working effects with aluminum alloy when used in low powered LED lamps (lower than 2W). For high powered LED lamps, the cooling efficiency is even worse than the material mentioned before. The final temperature of LED PN junctions for a 6W LED Spot Lights (using this type material as radiator) is up to 92 oC. Although some plastics have good capability of heat radiation, but thermal conductivity of them is too low. They absorb those heat generated by LED chips in a very slow rate. If the heat generated by LED chips dramatically exceeds their digestion, they will lose the cooling function completely. Similar to porous structured ceramic, conductive plastics did not exist very long in LED lighting market.

 

These two cooling materials for LED lamps are not competent. In next section, we are going to discuss the performance of graphite material.

wholesale led bulb for led’s future

According to Display Search research,  LED lighting demand will be continued growth in these coming years, also for the wholesale led bulb.
According to DisplaySearch’s latest Quarterly LED supply / demand market forecast report, a variety of market indicators, LED applications, it is expected that the lighting leading the way to 20% in 2010. In 2014, the overall income of the backlight and lighting is expected to be $ 7.2 billion increase from 2010 to $ 12.7 billion. The high demand for LED high bay lighting is the main driving force for this growth.
Fortunately, suppliers have already noted that these trends, and as early as ready to expand production capacity. DisplaySearch predicts the global LED production capacity will reach 227 0 billions in 2013.

wholesale led bulb for led's future
LED-backlit LCD TV in the fourth quarter of 2010, the first quarter of 2011 and the beginning of the second quarter of 2011, high inventory and low sales, resulting in a slight decrease of demand for LED backlighting; We believe that due to seasonal demand, it pick up again, and reaches its maximum in the third quarter of 2011. wholesale led bulb also the same future.

Regional market forecasts of LED lighting Japan in 2011 the world’s largest LED lighting market this year, the country’s market share of 63% in 2011 woulbe be  40% in 2014. Japan’s high investment in LED lighting, mainly due to the efforts of the country’s power shortage and energy-saving energy. Until 2014 will remain the world’s largest LED Street Light lighting market, 2011-2014, the growth rate of the LED lamps in China, North America and Europe will be higher than in other regions. wholesale led bulb would be sold very good in China.

In 2010, South Korea is the world’s largest LED supplier, in 2011, Taiwan get the first place. In 2011, chip size 500×500 of the top three suppliers were the S-LED, LGIT and Epistar, Due to substantial investment in the LED production,  Mainland China has become the biggest dark horse LED supply.
With the rapid growth of the market in the next few years, the price advantage and the right strategy LED suppliers will face a very big challenge. 2011 investment in LED lighting in full swing, excess capacity would increase competition and lead to price fell sharply.

wholesale led grow lights in LED Tunnel Lights

With the growing number of projects of the tunnel, the tunnel construction play an increasingly important role in modern transportation. The tunnel is for a closed space, which natural light can not be irradiated,  in order to ensure continuity and vehicular driving safety of human life, even during the day inside the whole need of artificial lighting, tunnel lighting is an integral part of the tunnel construction. Then what about wholesale led grow lights?

The tunnel lighting is different from the general lighting of the road, with its distinct specificity, and safety considerations are particularly important in the lighting system. Human adaptation and dark adaptation factor should be taken into account in the design of tunnel lighting program, attach importance to the transition section and transition section of lighting design.  The exit of the tunnel due to the adaptation time is very short, usually in less than 1s, so do other processing. I think wholesale led grow lights are the same concept.

 

wholesale led grow lights in LED Tunnel Lights

The general tunnel visual problems of the following:

(1) before entering the tunnel (daytime): great brightness difference of inside and outside of the tunnel, so to see from the tunnel external lighting is very full of the tunnel entrance will see the “black hole” phenomenon.
(2) After entering the tunnel (daytime): Automotive by bright external to enter even if not very dark tunnel, after a certain period of time to see the inside of the tunnel, known as “adaptive lag” phenomenon.
(3) exit of the tunnel: during the day, the vehicle through a long tunnel near the exit, due to the external brightness high to see through the export, the export appears to be a “white hole”, there will be a strong glare, the driver will not feel; night and day on the contrary, see the exit of the tunnel is not a bright hole, but the black hole, so that the driver not see the external road linear and obstructions.wholesale led grow lights are also the same such as LED high bay.

In the daytime, the lighting brightness of the tunnel exit and entrance lighting levels should be higher than the tunnel lighting luminance values; at night, on the contrary, it should be less than the tunnel lighting brightness value, when the street lighting in the tunnels, The surface brightness values ​​within the tunnel shall not be less than 2 times the outdoor brightness values.

how to buy wholesale led lamps?

From market research firm, Strategies Unlimited Tim Carli, they pointed out that  in the short term, LED lamps can not become a viable lighting solutions  in large quantiy. So, how to buy wholesale led lamps?

LED replacement lamps and Prospects in the content essence, an inventory of the market launch in 2009, a variety of LED replacement lamps, and thus proved that the LED replacement lamp into millions of households is not empty chatter.
Strategies Unlimited (www.strategies-u.com) last year published a report, “2009 LED replacement lamps and Prospects “. Through the analysis of five types of LED lights, including type A and dome lights, PAR and R lamps, MR16, chandeliers, decorative lamps and linear fluorescent tubes, the report pointed out that the legal prohibitions issued as countries awareness of the cost of ownership, coupled with customers, these will be the driving force of the LED replacement lamp in the next few years. how to buy wholesale led lamps?

how to buy wholesale led lamps?

Europe, America and Asia will start to accelerate the promotion of the use of LED lighting bulbs, to replace the traditional incandescent bulbs. European regulations came into effect from September last year to prohibit the use of 100W or more incandescent light (clear glass lamp); and between now and 2012 will gradually ban all inefficient incandescent 2016 turn all incandescent lights. Similarly, the U.S. Energy Information and Security Act 2007 banned the sale of inefficient light bulbs in the United States in 2012, this rule will be without deepening into “Where inefficient light bulbs will not sell”. The previous few years, Australia and other countries have announced the incandescent ban.

Therefore, the current situation is favorable for the LED replacement lamps, with the falling cost of LED lights. Among the entire market in constant growth, governments and consumers are looking for continuous improvement of energy saving solutions to reduce design and manufacturing costs, customers will eventually accept the cost of LED Street Light slowly.
Commercial LED performance in recent years has made leaps and bounds, product prices have decreased significantly, it will be possible to design a high luminous flux LED lights, its cost of ownership with other lighting technologies compared. how to buy wholesale led lamps?

LED replacement lamps in the short term as a viable lighting solutions, government departments, continues to inspire the CFL. However, within the next five years, LED technology is relatively CFL’s advantage will be presented one by one. Well-designed LED lights, the effective number of lumens can compete with CFL very soon.

Analysis for new cooling material for LED chips

Copper is the oldest cooling material for LED chips. In the beginning, LED Street Light chips are fixed on copper bases. Since copper has very good thermal conductivity, heat generated by chips can rapidly transfer into cooling devices. Even now it is still the best packaging material for chips. However, in the early stage of LED lighting, copper bases cannot be well connected with cooling devices directly. Most heat generated by LED chips gathered on copper bases, cannot be further transferred into cooling devices. In order to solve this problem, aluminum plates were set between copper bases and cooling devices. Due to this problem, aluminum was wildly used later in LED Tubes packaging. Then designers installed LED chips directly on aluminum plates. This packaging method is the prototype of COB.

 

Copper is the oldest cooling material for LED chips. In the beginning, LED chips are fixed on copper bases.

 

In next few years, a new cooling material for LED chips started to emerge: ceramic. Ceramic used for LED packaging should have better insulating capability and higher thermal conductivity. Currently, there are three types of ceramic material are competent: alumina, aluminium nitride and beryllia. Beryllia is toxic. Aluminium nitride has a very high thermal conductivity in theory but is not. In practice, the measured maximum thermal conductivity value of aluminium nitride is approximately 150-200 W/(m oC), very closed to the thermal conductivity of aluminum alloy. Since aluminium nitride is much more expensive than aluminum alloy, this material is also unsuitable for LED lighting. The thermal conductivity of alumina can be various depending on the constitutions of them. 95% purity has a thermal conductivity of 21.8 W/(m oC) and 36 W/(m oC) for 99% purity. It is much lower than aluminum alloy, not mention copper. But ceramic is isolated. In order to realize the function of cooling along with isolation, designers have to utilize this kind of material at the cost of thermal conductivity. Ceramic are fragile. When LED products subject to strong vibrations and pressures, they will be easily destroyed. Meanwhile, ceramic has much lower coefficient of thermal expansion than copper and aluminum. When there is a large change in temperature, ceramic base will generate a stress to destroy LED chips.

 

Above all, copper is the most suitable material for cooling system, then aluminum alloy. Only when insulation needs to be concerned, ceramic material and will be used.

why led lighting is better?

With energy saving, environmental protection, long life, small size and other characteristics, LED High bay now can be widely applied in various directions, display, decoration, backlighting, general lighting and urban night. LED with solar panels in the field of road lighting effective combination to create new markets for photovoltaic applications and LED combination.  However, if we want the solar LED to achieve large-scale application, we must resolve issues such as cost, standard. why led lighting?
The LED lighting market prospect is very broad,  It is estimated that 30 percent of the world’s street lights will be turned to the use of solar LED integrated lighting system can save 460 billion kwh of electricity consumption per year. LED lamps will become one of the direction of development, but its performance instability, high cost, short life are still the problems to be overcome. Promotion in recent years, the solar LED lights, solar and LED lighting to find the point of integration. Solar LED street lights solar panels and a dedicated battery, while the ordinary sodium lamps replaced with LED lamps. why led lighting?

why led lighting is better?
Solar street light take the control of a distributed circuit, the lights off, the energy conversion used in all the intelligent control, without manual operation, thereby reducing maintenance costs.
Solar LED street lights, compared with the high-power LED, low power LED costs are also full of advantages. Power consumption of high-power LED, matching the area of ​​solar panels increases the capacity of the battery, and therefore costs. The low-power LED street lights only
2/3 of the cost of high-power LED street. Compared with high-power LED lighting systems, low-power LED lighting systems could save 40% heat sink materials. In addition, ultraviolet and infrared spectra of small power LED, heat and radiation, is a typical green lighting. why led lighting?

Also, single power LED does not light, does not affect the normal light-emitting panel other diode when the circuit board due to fatigue or other reasons can not continue to use. You can replace the entire board, easy maintenance and reduce costs. Reporters told that the data show that in 2010 to install 220,000 solar power LED lights, the use of a large number of aluminum. If using low-power LED as light source, you can save aluminum ingots 39,600 tons.

LED white light created by LED chips and fluorescent powder

There are two methods for producing LED white light: LED chips together with fluorescent powder; combination of multi-single-color LED chips.

 

Blue-ray LED High Bay chips with fluorescent powder is the most commonly used method to generate white rays. With current fluorescent powder technique, man-made LED white rays still have big differences with natural white rays. That is the reason why white LED lamps usually have low color rendering index. Feature below shows the light spectrum distribution. From it we can see that the blue-green rays and red rays are insufficient. However, the blue rays are excessive. R9 (color rendering index for crimson) = 0.

 

Many people raised doubts about this colorimetric method. LED lighting sources have discrete light distributions while colorimetric method is typically used for testing continuous light spectrum. However, those who hold such views misunderstand the lighting principle of this LED white light. The lights emit by fluorescent powder (after being stimulated by blue rays) are not single-color rays, but contained most of visible lights. In fact, no matter what type of spectrum distribution, if it has a spectrum distribution very closed to natural white rays, it has a very high color rendering index.

 

There are two methods for producing LED white light: LED chips together with fluorescent powder; combination of multi-single-color LED chips.

 

Some people also come up with the concept that LED white light must have a relatively high color rendering index, since objects under LED white rays will be more bright-colored. However, this view is totally wrong. LED white lights indeed have very strong light intensity within some wavelength region (blue and yellow), but weak light intensity in other regions, like blue-green and red. Therefore, they just make some color of these objects look brighter. In fact, this is a performance of distortion. These objects will have different color if they in the sun. LED white lamps on the one hand excessively reveal some rays, and on the other hand insufficiently reveal some other rays. Some objects will look gloomy under LED white lights, like meat. In some LED-lights-decorated supermarkets, shopkeeper often installed some additional filament lamps in meat region to make their meat look brighter and more attractive.

 

With current technique, the distortion of LED white lamps (LED chips with fluorescent powder) cannot be eliminated. However, with the continuous development of LED Street Light technique, we believe this problem will be solved in future.

 

wired led bulb used for LED Street Lights

 

LED lighting is recognized as the next generation of green and low power consumption lighting technology. Single view from the luminous efficiency, LED light now has to reach and exceed the level of conventional light sources, but due to the expensive cost, they are still blocked in the popularity of LED lighting. As far as I think, wired led bulb cost problem is from the LED heat sink.

wired led bulb used for LED Street Lights

Street lights, long working hours, is considered to be the first choice for LED lighting applications. After the Chinese Government’s actively promoting, the total number of applications of LED street light in China now is leading the world. But the light fades, black lamp failure is widespread, and several hundred million RMB boondoggle. The cruel results of LED street (wired led bulb) show that: LED light source and power dissipation are still the problems which is not resolved. As we all know, LED cooling temperature and power are not very high, belonging to the room temperature heat transfer, heat transfer and talk, the LED heat dissipation is not complicated, involving only a very small part of the heat transfer. The thermal conductivity of heat transfer can use off-the-shelf heat transfer calculation software, a very accurate solution.
Leading to simple LED heat problem is complicated, has not been solved: the knowledge gaps, with the rich heat transfer of knowledge and proven technology personnel. To participate in the study of LED heat (wired led bulb) poorly,  it will cause hundreds of years of human mature transfer knowledge and technology is not introduced into the field of LED heat. Popular in the electronics cooling industry, active cooling, passive cooling, there is no such
terminology in the heat transfer. Only in respect of these terms, we can conclude: in the LED High Bay industry within today’s popular “Heat Transfer” (electronic cooling industry) does not originate from nearly a hundred years old, very mature of heat transfer, but start all over again, by a non- heat transfer to build.

This fundamental basic knowledge of heat transfer is a very important concept, not to be, a focus on industry in general.
This article will focus on heat transfer, cooling to analyze the progress of LED street tragic reasons for the technical level.

 

Properties of LED replacement tubes

Commonly used LED replacement tubes are T8 LED tubes and T10 LED tubes. They are new lighting technologies. However, compare with traditional fluorescent tubes, what are the advantages of LED tubes?

 

LED replacement tubes are the best energy-saving tubes presently. T8 LED tubes with power consumption of 15W can replace 40W-80W traditional fluorescent tubes, and can save more than 60% energy. They have been widely used for commercial purpose and residential purpose.

 

Commonly used LED replacement tubes are T8 LED tubes and T10 LED tubes. They are new lighting technologies. However, compare with traditional fluorescent tubes, what are the advantages of LED tubes?

 

More comfortable: Due to the ultraviolet rays sent out by fluorescent tubes, mosquitoes are usually attracted and gathered around them. Most of them even entered the internal of tubes and died there, leaving countless dark spots and reducing the brightness of tubes. However, LED replacement tubes can eliminate such annoy problem. There is no ultraviolet ray generated by LED lamps. Customers used LED tubes do not have to worry about mosquitoes.

 

Small light attenuation factor: LED tubes applied the most sophisticated manufacturing technique, use SMD 3528 LED chips. The light attenuation factor has been reduced into a lowest level. The average light attenuation after 5000 hours is only 8%. The average light attenuation after 30000 hours is around 30%.

 

Easier installation and maintenance: there is no need to change circuits, no need to modify ballasts, no need to change covers. They only thing that customers need to do is to remove the starter. LED tubes are much quieter than fluorescent tubes. They emit much less harmonic waves, the best lighting device in places where sophisticated electronic equipments are used.

 

Higher conversion efficiency: traditional lamps are always overheated. They generated a lot amount of heat during their work. Because they have a very low conversion (from electric energy to optical energy) efficiency. LED replacement tubes can convert more than 80% electric energy into optical energy, dramatically reduced the waste of energy.

Soft LED Street Light, good for your eyes: traditional tubes work under AC, thus will generate flickers with a frequency of 100-120Hz. Since the frequency exceeds our sense function, these flickers cannot be seen by us, but are actually harmful for our eyes. LED tubes work under DC, there is no flicker phenomenon. This kind of tubes can be in classrooms, libraries, in where students need to spend a lot of time on reading and writing. These tubes can protect their eyes and reduce the risk of myopic eyes.

Chinese LED manufacturers contend in Japanese LED lighting market (2)

Watanabe Yasushi from Japan JET Lighting Department has a different point of view. “After the earthquake happened in March last year, more and more Chinese products swarmed into Japanese market. Within several sampling inspections, we found that many Chinese LED bulbs cannot work as long as 50000 hours as marked. Most of them had the same problems: power suppliers and overheat.” Watanabe Yasushi indicated that more than 50% LED products from China is unqualified due to their unfamiliar with Japanese LED lighting standard.

 

Watanabe Yasushi from Japan JET Lighting Department has a different point of view. “After the earthquake happened in March last year, more and more Chinese products swarmed into Japanese market.

 

At the same time, Chinese LED manufacturers suffered fierce competitions from local LED manufacturers. Panasonic, the largest lighting enterprise in Japan, decided to promote a restructuring plan: combined Panasonic Lighting (a sub-company of Panasonic) with its Lighting Department together as a giant Lighting Business Group. Panasonic indicated that, after this reconstruction, the annual sales of 2012 are expected to reach up to 35 billion yen. The annual sales of 2015 can reach up to 100 billion yen. In which LED products will occupied more than 40% of Japanese local lighting market.

 

Meanwhile, another local brand Toshiba is stepping up the penetration in Japanese LED bulb market. Sato Koji, director of LED Business Department of Toshiba indicated that the increase of LED month sales is significant in 2011, from 2.8 million in June to 4.8 million in December. The annual growth is over 300%.

 

Competitions from local brand brought huge pressure to Chinese LED manufacturers. “Japanese have the traditional channels for sales. But it is very difficult for Chinese manufacturers to get into. Even for ordinary LED lights, we can only import our products though an exclusive agency set in Japan firstly, then transfer them into traditional channels. We are planning to be the OEM for Japanese local LED brands, this is another way to enter Japanese lighting market.” said Jiawei Pang, general manager from Tong Pu technologies Co,. Ltd.

 

General manager Mr Xiao from Shengzhen Juzuo Industrial Co., Ltd. has studied Japanese market for many years. According to his words, it is impractical for Chinese LED High Bay products promiscuously enter Japanese market. “Our manufacturers need to do sufficient research before entering Japanese market, choose several flagship products according to the specific conditions of it.”