作者：Blade

The long term degeneration of white LED light engine

 

The long term degeneration of white LED light engine

 

Traditional white LED light engine is directly coated with yellow phosphorus phosphors on a blue LED, white LED lit, the heat is difficult to distribute, yellow phosphorus phosphors in the long-term high temperature BBQ is easy to degeneration, resulting in significant use for a long time after color index variation. LED lamps, such as yellow phosphorus phosphor directly coated white LED light engine, but filter made ​​of a yellow phosphorus, to maintain a certain distance with the blue LED in the fixture, the two superimposed using the same samples can be obtained white or warm white light of the LED lighting effects. The yellow phosphorus filter away from the LED heat, therefore, aging degeneration due to the LED light source of long-term high-temperature grill, CRI is essentially the same; yellow phosphorus filter with side adjustable, lighting, color, color temperature with the modulation of the needs of customers, which can meet the customized requirements and poor production alienation of the product.

 

The blue LED light engine architecture is an innovative concept, completely different from the aforementioned white LED light engine. Blue LED light engine will be the blue LED light source plate, the AC / DC constant current drive power board. The yellow phosphorus filter is integrated in one. Its structure principle shown in Figure 5, the mains via the AC / DC constant current drive power transform the output constant-current DC lit blue led high bay light source, blue, yellow phosphorus filter to the LED light the engine makes white or warm white.

ZHAGA union in LED street lighting projects entered Chinese market

 

ZHAGA union in LED street lighting projects entered Chinese market

 

Dreams can come true!, LED lighting, LED light source and the AC / DC constant current drive power integration module —- LED light engine has been born, and can be mass-produced. LED lighting enterprise, traditional lighting plant and the new entry can be very convenient LED light engine for the mass production of the new LED lighting, thereby speeding up new product design to volume production process, greatly reducing the development cycle of new products . The LED lighting market calls for the LED street lighting projects early birth, and entered the lighting market as soon as possible.

 

Today, a challenge for LED street lighting projects designer and user, the light source drive circuit between no standardized interfaces. European ZHAGA Alliance launched an industry-wide action for the LED light engine development standards to regulate. The LED light engine with the provisions of the interface LED modules, and these interfaces has nothing to do with the type of internal use of the LED light engine technology. In fact, in early February 2010, Cooper, Lighting, Osram, Panasonic, Philips, Toshiba, including nine of the lighting industry giant announced that it will initiate the establishment of a Cooperation Organization — ZHAGA associated Union, are participating members of 25 companies.

 

The ZHAGA Union aimed at developing the led high bay light engine (light engine) interface interface standards so that different. The manufacturers of the products are interchangeable. To cope with the sustained and rapid development of LED technology, by defining a variety of special light engine interface information, ZHAGA, the standard will cover physical size, and LED light cited the engine of the optical, electrical and thermal performance, and ultimately ZHAGA alliance between different manufacturers products compatibility, interchangeability.

Led lamp china has become a major trend of the future energy-efficient lighting

Led lamp china has become a major trend of the future energy-efficient lighting

“LED lighting industry, is a revolution, not just a substitute for traditional light sources. Toshiba Lighting to reach the common aspiration is to better play out of the features of LED products, making this the revolution of the lighting industry to more thoroughly and more rapidly. “America’s Minister of Ministry of lighting, led lamp china,commercial lighting project segment says.
Beautiful lighting and Toshiba success “in hand”, follow-up development planning has also become the focus of widespread concern by the industry. In this regard, the lighting commercial lighting project, Minister of paragraph spring, said: “The first step in the lighting of the United States and Toshiba strategic cooperation, first of all will be reflected in industrial design. New LED products will be a large number of applications mature Toshiba LED module Second, the amount of advantage in industrial design, led high bay combined with America, as well as large-scale manufacturing and channel advantages, and strive to provide the market with excellent cost LED products, and promote energy-saving replacement of the lighting industry. electrically, the two sides in the LED driveintelligent control, led lamp china, intelligent dimming more in-depth cooperation. ”
It is understood that during the period in the United States signed a strategic agreement with Toshiba, beautiful lighting, market-oriented heavy launched a 60-variety of business according to new LED products include LED ceiling spotlights and LED downlight. The bewildering variety of these LED tube lighting, with the flexibility to choose a variety of colors and materials, the light source deep adjustable, easy to install, led lamp china,to fully meet the workplace needs of engineering a variety of applications of the commercial channels.With electrical sales, a direct replacement for ordinary ceiling spotlights, is also very suitable for the home to promote the use of the professional market.
Beauty lighting the future development prospects, the Lisan Long said: “to create a new era of lighting industry in China, and lighting in the United States to achieve the grand vision of the overall world-class lighting solutions provider, to make a difference in international and domestic markets.”

LED household lighting market calls for the LED light engine

LED lighting design variety prevails, the inconvenience to the production, use, and industrial management, in particular the transition from traditional lighting plant to the LED lighting plant, or just entering the initial of the LED household lighting industry, will feel overwhelmed, where to start as well? Just enter the LED lighting industry, in order to reduce the risk and cost, often only to buy off-the-shelf LED lights source lamp board, AC / DC constant current drive power, aluminum or ceramic such as the radiator assembly. Traditional lighting plant owners as effort as well buy a light bulb, buy a ready-made “LED Street light + AC / DC constant current drive power” module into its traditional lamp housing can be magnificent turn as a the new LED lighting.

LED household lighting market calls for the LED light engine

 

The rapid development of LED lighting, a mighty force competing to join the new company was born in the world almost every day, especially the interior lighting of the mass market, forcing traditional lighting companies to tap into joining. LED household lighting is an electronic product, it requires not only such traditional lamps that structure, the shell must also be given a variety of string, and parallel matrix LED light source lamp board, AC / DC constant current drive power, aluminum or ceramic, etc. heat , led high bay lighting market calls for the LED light engine lighting manufacturers need to employ electronic, optical, structural design engineer; traditional lighting is only one electrical products, traditional lighting manufacturers design, structural modeling of the production of lamps, the light source —- bulb bought to the professional factory plug will be able to use universal.

 

How to predict the life of the LED bathroom downlights

 

How to predict the life of the LED bathroom downlights

 

From the junction temperature to speculate that life seems to be very simple, just check the graph in Figure 1, you can know that life for the junction temperature of 95 degrees you can get the LED life of 20,000 hours. However, this method is used for indoor LED bathroom downlights have a certain amount of credibility, if applied to the outdoor LED lamps, especially high-power LED lights, where there are many uncertainties. The biggest problem is the radiator cooling efficiency of led high bay lights is reduced over time. This is due to the accumulation of dust, bird feces makes its cooling efficiency. Also very strong because the outdoor ultraviolet rays also cause reduced life of the LED. UV is mainly the aging of the epoxy resin package play a big role, if the use of silicone, can be improved. There are some bad effects of UV on the aging of the phosphors, but not very serious.

 

Two voltage temperature to remove, you can get the temperature coefficient, expressed in mV / oC. For ordinary silicon diode, the temperature coefficient of about -2mV/oC. LED bathroom downlights most are not made ​​of silicon, so its temperature coefficient should another go determination. Fortunately, various LED manufacturers data sheets, most of its temperature coefficient.

 

However, this method is used to relatively compare the two radiator cooling effect is more effective. Obviously, the volt-ampere characteristic left the smaller radiator, the heat the better. In addition, the life prediction of indoor LED bathroom downlights still have a certain degree of accuracy.

How to measure the LED junction temperature for LED street lighting projects

 

How to measure the LED junction temperature for LED street lighting projects 

 

We know that the LED street lighting projects is a semiconductor diode, the same as a volt-ampere characteristic, and all diodes and semiconductor diode volt-ampere characteristic of a temperature characteristic. Its characteristics when the temperature rises, the volt-ampere characteristic left.

 

To illustrate how estimates of LED junction temperature. To LED street lighting projects installed inside the radiator, and is a constant current drive power. Should connect to the LED to the two line leads. Put in power before the voltmeter connected to the positive and negative terminals of the output (LED), then connect the power to take advantage of LED heat up before, immediately read the readings of the voltmeter, which is equivalent to the value of the V1, and then at least 1 hour, it has reached thermal equilibrium, and then measured once, the LED voltage across, which is equivalent to V2. These two values ​​subtract the obtained difference. Be 4mV removal, you can come to a junction temperature. In fact, the led high bay lighting is mostly for a lot of series and then parallel, that does not matter when the voltage difference is shared by many series of LED and contribution, so take this voltage difference is divided by the number of LEDs in series is again divided by the 4mV, you can get to its junction temperature. For example, the LED is a 10 string 2 and the first measured voltage is 33V, measured after the second thermal equilibrium voltage of 30V, the voltage difference of 3V. This figure is first divided by the number of LEDs in series (10), and get the 0.3V, divided by 4mV can be 75 degrees. Assumes that the boot before the ambient temperature is 20 degrees, so that when the junction temperature should be 95 degrees.

 

 

How to extend the life of LED chips used in led high power bulbs

 

How to extend the life of LED chips used in led high power bulbs

 

Here we are not prepared to discuss the problem of how to design a radiator, but to discuss a radiator cooling effect is relatively good question. In fact, this is a junction temperature of the measurement problem, if we can measure the junction temperature of a radiator that can be achieved, then not only can compare the radiator cooling effect, but also know that using this radiator can achieve led high power bulbs life.

 

Junction temperature appears to be a temperature measurement, but the junction temperature to be measured inside the led high bay, we can not take a thermometer or thermocouple into the PN junction to measure its temperature. Of course, the case temperature can still be measured with a thermocouple, and then given thermal resistance Rjc (junction to case), one can calculate the junction temperature. But after a good radiator is installed, the problem becomes complicated by the Because usually the led high power bulbs is soldered to the aluminum plate, aluminum plate installed on the radiator, if only measuring the temperature of the radiator shell, then to calculate the junction temperature must know a lot of thermal resistance value of. Including Rjc (junction to case), RCM (housing to the aluminum plate, which should include the thermal resistance of the film printed version), Rms (aluminum plate to the radiator), of Rsa (radiator to the air), which has a data inaccurate will affect the accuracy of the test. Figure 3 shows a schematic diagram of the LED to the various thermal resistance of the radiator. Merged a lot of thermal resistance, and its accuracy is more restricted. In other words, the radiator surface temperature to infer from the measured junction temperature accuracy is even worse.

The light decline of RGB LED downlight

 

The light decline of RGB LED downlight

 

Everything has to happen, the process of development and demise of the RGB LED downlight is no exception, there is a certain life. Early only flashlight LED table lamp such gifts, time spent not long life issues. The LED has widely used in outdoor and indoor lighting, especially high-power LED lights, its power, high fever, long working hours, and life issues are very prominent. The past that the RGB LED downlight life must be the myth of 100,000 hours seems completely shattered. So in the end where the problem is it?

 

Most of the white LED has been irradiated by the blue LED yellow phosphor. There are two main reasons caused by the LED light failure, a blue LED’s light fades, the blue LED light failure than red, yellow, green LED. There is also a phosphor light failure, phosphor decay at high temperatures is very serious. Various brands of led high bay light failure is different. Usually LED manufacturers are given a standard set of light decay curve.

 

RGB LED downlight light decline and its junction temperature, the so-called junction temperature is the temperature of the semiconductor PN junction, the junction temperature the higher the sooner the light fades, that is, the shorter the life. Can be seen from the chart, if the junction temperature of 105 degrees, the brightness dropped to 70% of the life of more than 10,000 hours, 95 degrees there is 20,000 hours, while the junction temperature cools to 75 degrees, there are 50,000 hours life 65 degrees can be extended to 90,000 hours. Extend the life of the key is to reduce the junction temperature. However, these data are only suitable for the Cree LED. Not suitable for other LED.

 

 

LED industry increased 42% in the first quarter,led high hat bulbs companies jointly seek breakthroughs

LED industry increased 42% in the first quarter,led high hat bulbs companies jointly seek breakthroughs

Recently, the lighting in the United States to join hands with Japan’s Toshiba Lighting appearance, both sides announced that LED lighting products and technology to achieve the strategic partnership. Since then, the lighting of the United States following the March 2011, the Shanghai Hotel Show to launch the first batch of LED products, LED lighting products and technology a big step forward step; At the same time, led high hat bulbs, the United States also became Toshiba Lighting the largest partner in China.
Insiders said that with the accelerated pace of China’s lighting industry, “powerful combination” has become a lot of new ways of lighting fast break. The beautiful lighting and Toshiba entered into a strategic cooperation, not only can effectively promote the beauty of exploration and development of sophisticated commercial lighting market, led high hat bulbs,but will also further promote China’s LED industry chain and technology upgrades, the cooperation between the two sides will open a common win a new situation in the era of the LED lighting.
In recent years, China’s LED lighting industry is growing rapidly. From the China Association of Lighting statistics show that only 2012 first quarter, China LED applications, the output value reached 19.9 billion yuan, led high bay, an increase of 42%. China Illuminating Engineering Society executive vice president and secretary general of Xuhuai said: “In the case of energy saving by the unprecedented attention, the country has LED lighting as a key development areas, led high hat bulbs,it has become one of the most important changes of the Chinese lighting industry.”
However, the rapid development of the market at the same time, China’s lighting industry, lack of core technology, the lack of innovation capability has become more prominent.”On the whole, there are still about two years the gap between China and the world-class.” Feng-Yi Jiang, vice president of the Nanchang University believes that “many developed countries, developing countries and regions in the world are accelerating the semiconductor lighting technology and industrial development, led high hat bulbs,technically, still in the second echelon. “

Constant voltage supplier is not suitable for mains LED lights

 

Constant voltage supplier is not suitable for mains LED lights

 

Many a variety of fallacious argument on this issue, it was said: the volt-ampere characteristic of the LED, the voltage is set, the current set. So the constant voltage and constant current effect is the same. Some people say that the constant voltage power supply mains LED lights in parallel should be used, and the LED constant current power supply should be used in series; Some people say that, because the mains LED lights constant current devices, so use constant current power supply; Some people say that using electricity supply should be a constant voltage power supply should be used when using battery power, constant current power supply. As for why such a request, it seems, who also did not understand.

 

So, what should be a constant voltage power supply, or a constant current power supply?

 

First look at the LED in the end is what kind of device. LED brightness is proportional to its forward current, and some of the LED structure determines its cooling power. Most LED will give the rated current, such as Φ5 20mA 1W 350mA … and so on, but that does not mean that the LED can only work in those rated current, but does not mean that the led high bay light is a constant current devices. For example, the Cree 1 watt LED and 3-watt LED is the same model, the current increased from 350mA to 700mA power from 1W to increase 3W, so the mains LED lights can be any value between 350-700mA.