2012年10月 – 第2页 – LED Lighting Blog

How to evaluate the LED lighting circuit design?

LED chip is the core technology of LED lamp, and the entire industry has also put a lot of effort on this part. However, no one can deny the importance of LED drivers. LED drivers/power supplies are usually considered as the short board of LED lamps, which may probably determine the service life of the lamp. However, it is LED lighting circuit design that determines the quality of LED drivers. Overall, volume and cost are two major factor of judging the LED lighting circuit design, but some manufactures and inspection institutes also see PFC as an important reference indicators, as well.

Observing from the whole LED lighting system, there is no doubt that LED chips and packaging accounted for a fairly high proportion of the overall production cost. LED lighting circuit design is not the most important part, but is a key point to determine the energy efficiency of a LED lighting product. On the other hand, the LED industry also faced with other strict requirements on cost, lifetime and volume. Under the circumstance of facing multiple pressures, system makers would like to shift these pressures to semiconductor producers.

Different applications, different LED lighting circuit designs. Normally, LED lighting applications can be divided into three types: indoor lighting, outdoor lighting and automobile lighting. Although they can be further divided, but internal circuits will be slightly different among LED lighting applications from the same type. Only in the aspects of operation temperature, system volume, reliability and production cost, there will be large variations. For example, indoor lighting applications, like residential lighting and commercial lighting, will consider more about production cost and system volume. Outdoor landscape lighting is more concerned about the operation temperature and reliability. For automotive lighting, although operated under DC, electrical safety needs to pay more attention on.

LED outdoor lighting applications should have a higher IP level and stronger in resisting the stressed environment. But at present there is no cleared unified standard in the outdoor lighting area. It is suggested that LED outdoor lighting applications still have a long way to go to obtain further improvements. In addition to environmental factors, as a matter of fact, LED outdoor lighting applications are usually high powered due to the multiple LED chips used on their light-emitting boards. Series connection will definitely increase the operation power, while parallel connection will increase the input voltage, which is infeasible for LED lighting applications. Thus solutions for LED Panel Light outdoor lamps should be comprehensive to meet the design requirements.

Reviewing LED technology 50 years: The Secret History from the lights to street lights

GMT, October 12, according to foreign media reports, GE executives show his inventions in 50 years ago. LED (light emitting diode) the inventor Senanayake (NickHolonyak) firmly believe that LED will replace incandescent bulbs. Although incandescent bulbs are still the mainstream product in the home lighting, yet LED has changed in many ways the lighting applications. From indicator to the high brightness of street lights on the streets of major cities to the faint red light switch, LED Panel Light has been accepted by the world.

Ubiquitous red LED

The first LED light glows red. This is not because of aesthetic considerations. The LED is made through to create a multi layered semiconductor wafer on the wafer. As more and more layers of a semiconductor wafer is added up, people began to use various additives to determine the color of the LED lamp. Small silicon wafer is immersed in the molten liquid, and then add the metal contacts and conductors. First GaAsP LED lights using LED lights of the solution will be to produce a natural red. Therefore, the default color is used as the indicator LED lights red.

Making use of new LED technology lights can also be issued to other colors of light, which greatly expanded the range of applications of LED lights. But LED lights after the advent of the first 10 years always emits the red light.

The first portable calculator
Relatively inexpensive, low-power LED lights began to replace incandescent bulbs in a variety of electronic products, electronic products, prices fell, down to the level of a more easily accepted by consumers.

First LED watches

In 1972, The watch LED technology which already exists as long as a century of have begun to accept the LED lights. Pulsar was launched the world’s first LED watch: Time-Computer. It is said that the watch extremely accurate, the annual run error is not more than 60 seconds. It is the first watch equipped with LED lights, and have electronic timekeeping function, the price at that time is $ 2100.

Unfortunately, this kind of watch have the high power consumption of this new technology, so people who wearing such watches need to press a button to see the time.

Enterprises still have limited knowledge about LED fluorescent tubes

Whether LED tube technology has entered the second stage and mature enough that can be commercialized, no one can give out a satisfied answer at this moment. There is also no LED Panel Light company that has done a complete 10,000-hour aging test. Many LED manufacturers have very limited knowledge about their products. Large brand LED fluorescent tubes usually have one-year warranty. The warranty of domestic LED fluorescent tubes varies according to the quality of products, from 1 year to 3 years. Currently, domestic LED interior lighting industry is under an unordered development. Lacking of cleared uniform standards, it is predicted that the price battle of LED lighting products will be continued for a very long time.

What are the differences between normal fluorescent tubes and LED fluorescent tubes? LED tube lights have higher quality, more durable and can save more energy, have wide options in beam angle, higher light efficiency (the brightness of a 15W LED Tube is equivalent to the brightness of a 40W fluorescent tube), can work in high temperatures, with anti-moisture/water-proof/leak-proof function. The commonly used covers for LED tubes are Glass cover and PC (Poly Carbonate) cover. LED tube lights use the most advanced lighting technology – LED, with digital appearance desighs, saving up to 70% energy. The service life of LED tubes is nearly 10 times longer than ordinary fluorescent tubes, almost maintenance-free.

LED tubes use green semiconductors as light source, very environmental friendly, soft rays, pure spectrum, providing more protection for human eyes and health. The 6000K Cool White light source gives a cool feeling to our eyes, which will make people be easier to concentrate and improve their working efficiency.

Currently, compared with traditional fluorescent tubes, LED fluorescent tubes have following advantages: 1) save more energy; 2) long lifetime; 3) Good applicability, since the small size of LED chips, they can be made in various shape; 4) short response time (several nanoseconds); the response time of fluorescent tubes is around several milliseconds; 5) environmental protection, no health-hazard metal waste, easy for recycling; 6) emit multiple pure colors (narrow spectral range, via combinations of red/green/blue rays). Disadvantages: 1) expensive; 2) great gap between theoretically light efficiency and practical light efficiency; 3) great gap between theoretically lifetime and practical lifetime; 4) the heat dissipation problem; However, all these defects can be improved by more advanced LED technology.

Some suggestions for LED tube market

Replace a 40W fluorescent tube with an 18W LED Panel Light tube. If compared the service life and selling prices between them we could find that: the average selling price of 18W LED tubes is 165-200 yuan, average ex-factory price is 135 yuan, the production cost is around 120 yuan. LED T8 tube, 18W, 1.2m, using Epistar 3528 LED chips, luminous flux of single chip is around 6lm, embedded isolated drivers, total luminous flux is approximately 1400-1600lm. If every LED T8 tube works 10 hours one day, 365 days one year, after two years, one LED T8 Tube can save energy of: (40W-18W) x 10 (hours) x 365 (days) x 2 (years)/1000W (one kilowatt hour = 1000W) = 160.6 kilowatt hour. Save money of 160.6 kilowatt hour x 0.9 yuan/ kilowatt hour = 144.54 yuan. The average service life of fluorescent tubes is one year. Two years need two fluorescent tubes. Then price difference between them should be: 165 – 10 x 2 = 145 yuan. Therefore, if LED tubes can be used for more than two years (7300 hours, it is easy for most LED tubs to work this long). According to the above calculation, LED tubes need at least two years or more to recover the cost of production and realize the final goal of energy-saving, which is also a piece of good news for the LED tube market.

The average selling price of LED tube is around 150-200 yuan/each. There is still falling space. At present, the average ex-factory price of LED tubes is about 6-20 yuan/W. Prices vary among different manufacturers. A cost structure of on 18W T8 LED tube: the light source accounts for 53%, the driver accounts for 14%. Obviously, light sources occupy nearly 50% of the total production cost. Light source part is the core technology of LED lights. Different technologies, different materials cause different tubes from different LED manufacturers cost different. The difference of selling prices may as higher as 200 yuan for some products with the same specification in the LED tube market.

Since November of 2009, with the increasingly intense competitions in the LED tube market, selling prices of LED tube lights continuously dropped. In the mean time, the demand for light sources, power supplies, lamp shells is also increased stably, making the production cost hard to be cut down.

When can LED tube products become the mainstream in the tube market

In recent years, as a new green energy-saving light source, LED enjoyed a vigorous development, from the outdoor landscaping lighting area to the indoor residential lighting area. In the very beginning of this year, many LED Panel Light manufacturers promoted new LED indoor lighting products. Among them, it was LED tube products that attracted most attention. Compared with traditional fluorescent tubes, LED tubes have many advantages: can save more energy, more environmental friendly, longer service life and smaller. Although, LED tube products are more advanced in technology, they still have not dominated the market and become the mainstream yet.

Expensive selling prices + unstable performances + insufficient supports make LED tubes hardly to be seen in the market. At present, most LED tube applications can only used in the industrial field and the commercial field, why they can hardly accepted by ordinary family? There are three main reasons: 1. Too expensive selling prices and unstable performances; 2. Inadequate supports and promotions from the government; 3. Many support policies but very few lighting projects. The cheapest LED tubes are 13 times more expensive than commonly used fluorescent tubes. The acceptance and acknowledge of this product among ordinary consumers are really low. LED tubes are more likely to be used for commercial purposes. But commercial lighting applications need to take account of multiple factors: energy-saving, environmental protection, appearance, government support, etc.. The unstable performances plus the unwarrantable service life plus government’s shifted focus from commercial lighting area to industrial lighting area made LED tube products even hard to find in the commercial lighting market.

PK with traditional fluorescent lamps, the over-expensive production cost of LED tube lights is real. But the 50,000 service life is not real. If take the lifetime, energy-saving effect and less pollution into account, LED is more cost-effective. The average service life of traditional fluorescent tubes is only 5000 hours. IF LED tubes can really maintain a normal condition for more than 50,000 hours, it is not surprised that the sell price of LED tube lights will be 10 times higher than that of traditional tubes. The energy LED lights saved during this time will become a pure income. However, the 50,000 hours story has been questioned.

Online shopping will become the new battleground of LED lighting business

It is rather difficult for current LED lighting business quickly enter into distribution channels established for traditional lighting industries. Offline businesses usually need huge upfront investments. Relatively, online sales have two obvious advantages: low upfront investments and wide coverage, which is more suitable for LED Panel Light this emerging market.

Online sales have two major features: wide purchase groups, without any regional restrictions; flat management, reducing intermediate links in circulation.

In addition, it is very hard for ordinary consumers to buy any high-quality LED lighting products from stores, supermarkets or other traditional channels. The over-expensive production cost blocked them from the residential lighting area. “They are too expensive to sell. No one would pay 50 USD to by a 50W bulb. Ridiculous!” said one of merchants of lamps. Currently, only 5% traditional lighting channels are also doing LED lighting business. WAL-MART is the only large supermarket that selling LED lighting products. Therefore, those who have some knowledge on LED lighting lamps and feel interested in this new lighting technology can only find what they want from the internet. Actually, compared with offline trading, LED is very popular in the online market.

According to a Taobao internal staff, they had once sold a type of LED bulbs at the price of 39.8 yuan (group price) on the website. Just a few hours, 7000 LED bulbs have been sold out. In order to satisfy the demands of buyers, Taobao had to undergo emergency replenishment and carried out the second round of group purchase, with the same product.

Online shopping can effectively reduce the purchase cost of terminal users, at least 15%-30% compared with traditional channels. At the same time, online selling also provides channels for brand promotion and products present.

Online prices for LED lamps are much cheaper than that of LED lights offline sold. There is no rent fee, no utility bill, no staff salary, but LED online merchants are responsible for the management and promotion cost of the trading platform. After calculation, although online selling prices of LED products are cheaper, the profit margin is almost the same for online selling and offline selling. The current trading profit of LED online business maintained at about 20%, which still have large upward space.

LED lighting market: how to get over the hurdles of price and quality

In recent years, the Quality Supervision Bureau, AQSIQ(General Administration of Quality Supervision), Industrial and Commercial Bureau conducted sampling inspection for LED lighting products, energy-saving lamps, road lighting applications, fire emergency lamps and electric light sources all over the coming from 15 cities. The result is rather disappointed: only 51% of LED lamps pass the examination. The low FPY (First Pass Yield) cracked down the confident of the entire LED lighting market. Some LED makers even use halogen powder instead of tri-color powder, making this emerging market all but impossible.

As for the phenomenon that using “halogen powder” instead of “tri-color powder”, experts indicated that the selling price of the later is 2-3 times higher that of the former. Compared with halogen powder, tri-color powder is more advanced in many aspects: higher light efficiency, better CRI, longer service life, but relatively, cost more. These behaviors actually do harms for the sustainable long-term development of LED Panel Light industry. Paying more energy on technological research and development is the best way to cope with the intense competitions in the LED lighting market. In order to achieve this effect, we need restrictions of rules and regulations.

In addition to the quality problems, the over-expensive selling price is another big obstacle of the development of LED. Compared with traditional lights, the market penetration of LED lighting applications is only 5%. LED has been developed in the mainland for nearly 10 years, which is really short compared with other traditional lamps. It is very difficult for them to drop the price exponentially. Currently, the average cost of one LED bulb is around 5 USD, which is 10 times of the cost of one incandescent bulb.

LED lamps are mainly composed of LED lighting sources, drivers and cooling sections. Domestic LED manufacturers engaged in almost every aspect of this area: from chip producing to packaging to application. In order to reduce the production cost, many LED makers choose to develop their own LED driver circuits. Stability, technique factor and optical-electrical conversion efficiency are the three major factors that determine the quality of one driver.

Using self-developed drivers can dramatically reduce the production of LED lighting products, especially LED bulbs. In accordance with the law of market development, it is believed that the price of LED bulbs will drop dramatically within the next two years. Price cut caused by vicious competitions should be eliminated in the LED lighting market.

The low FPY (First Pass Yield) slows down the development of LED lighting industry

With the ban of incandescent lamps with power consumption larger than and equal to 100W issued by the National Development and Reform Commission on October 1^st of 2012, the LED lighting industry received strong supports from related government policies. It is clear that the entire lighting industry is transforming from traditional lighting to LED lighting.

During this period of time (when incandescent lamps have been gradually replaced by new lighting sources), LED lamps are not completely resisted by ordinary consumers. They just felt hesitate to accept. Currently, LED lighting products are still in an immature stage: unclear product identification, lacking of unified standard, products with different quality. Recently, the Guangdong Provincial Bureau of Quality and Technical Supervision spot checked some LED samples from different LED Panel Light manufacturers. The truth is the FPY of these samples is too low.

In this spot checking, among totally 23 samples (more than 100 for each sample) from 21 LED manufactures, 17 samples did not pass the test. The pass rate was less than 30%. The low FPY (First Pass Yield) slows down the development of LED lighting industry.

Experts gave advices about LED lighting products on the market:

1) Inspect the packaging at first: trademarks and certification marks are necessary, like 3C certification, CE certification, RoHS certification, etc.. Besides, some basic technical parameters also cannot be ignored: the rated voltage, voltage range, color temperature, precautions, safety instructions, application environment.

2) Price comparison: As a result of the expensive production cost, the average selling price of LED lamps is usually around 45 yuan. (Products from large brands will more expensive, like Phillips, OSRAM, etc.) Besides, the glaze surface is also very important, without any glue mark, without any protruded screws. And the color of screws should be identified with the color of the surface.

3) Buyers should carefully examine the color change after the lamp has been switched on. If the light changed from yellow to white or from white to blue-white during the short time after lamps being switched on, there must be something wrong the drivers or light sources. Also for small-power MR16 spotlights, using inappropriate transformers may cause flickers. High-frequency electronic transformers are more suitable for this kind of products.

The entry point of LED lighting market

Since October 1^st of 2012, China will gradually ban the import and sale of incandescent lights according to the power consumption. The phase-out process of incandescent lighting products has entered the implementation phase. New lighting source, especially the LED lighting industry will continue to obtain great supports from the government. LED lighting market has bright prospects and huge potentials.

LED lighting applications are speeding up their penetration into the market. For now, LED lighting industry is on the threshold of a dramatic boom.

The hottest LED lighting applications in the mainland is LED road lamps and LED Panel Light. With the support policy from the Ministry of Science and Technology, LED road lamps were promoting at an amazing speed. Both purchasers and suppliers showed their enthusiasm in this area. Presently, there are estimated one million pieces LED street lights will be installed in 21 pilot cities within ten years. And another plan of two million pieces LED street lights within 50 pilot cities is ongoing. This is a characteristic of China. This is a generation speed of China. It is too fast that this market may probably be destroyed by foams at the end.

In the LED T8 application area, according to the previous market plans, there are some mature commercialized products that had been promoted in the LED lighting market. It is believed that LED T8 application market is the first mature LED lighting market. The most commonly used LED T8 tube applications are parking lot lighting, shopping center lighting and advertising backlight. The selling prices in these area have already reach the critical point (150).

High-quality products have sophisticated technologies in optics, cooling designs and power suppliers. However, there are still a large number of low-quality LED products in the market, which is the biggest challenge for the commercialization of LED products. With the launch of standards from the Energy Star and EU, the above problems may greatly be improved.

Theoretically, lamp cover is the begging of lamps’ development. However, for a very long time, LED manufacturers could not solve the multi-specification problem and led to the embarrassing situation that the development of LED lamp cover is far behind that of the other compartments. Although the cost of LED lighting products has dropped sharply, there is still no major improvement in the global LED lighting market. Which LED technology can finish the commercialization and become the new darling of the market after LED T8 Tubes?

Brief analysis for LED lighting applications market trends

The bright development prospects of LED lighting applications make people feel more confident in the LED lighting market. Nowadays, the world is under the threat of energy shortage. Governments all over the world launched environmental protection policies and increase support in the LED industry. With the vigorous development of LED lighting technology, LED lighting applications has gradually transferred from street lighting, outdoor landscape lighting to indoor residential lighting and commercial lighting.

Currently, LED Panel Light has been deeply used in the residential lighting area. Although domestic LED market is still dominated by LED street lights (for industrial purpose) and LED flood lights (for commercial purpose), LED panels and LED downlights with dimming and RGB functions started to attract the attention of ordinary buyers and merchants. The over-expensive production cost is the biggest obstacle that hindered the promotion of LED productions in the residential lighting area. Thus after 20-year development, LED still can hardly be accepted by the household lighting market. Using sapphire as chip substrates, using gold as conducting material, there is no doubt that LEDs are also known as “noble lamps”.

It is estimated that by 2015, the market penetration of LED lamps will reach up to 16.8%. Under the stimulus of governments support policies, the penetration rate of LED household lighting applications and street lighting applications will sharply increased. LED bulbs and LED tubes are stable growing every year in Japan’s lighting market. The main force is from the earthquake happened in March 2011, in Japan. The Japanese Governments started to realized the important of energy saving and environmental protection. In the mean time, a large number of new LED suppliers entered this area and speeded up their production and development. Take 500×500 LED chips for example, compared with 2010, the overall supply raised by 41% in 2011. On the contrary, the demand grew only 10%, which led to the oversupply of 500×500 LED chips in 2011. 2011 is a challenging year for LED manufacturers. Due to the slow growth of we LED TV sales and the improvement of luminous efficiency of LED chips, since 2010, the TV backlight industry faced with demand reversal problem. But overall, the demand for LED in the LCD backlight applications is also slightly increased, pulse the improvement of PC and LCD display applications, which compensated for the gradually declined demand in the TV market.

LED Lighting Blog

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月份：2012年10月