Expo innovation technology highlights when LED lighting illuminates you and my home

As one of the highlights of Shanghai World Expo innovation technology, LED lighting technology has been applied in large scale in the Expo Park. Especially at night, LED lighting has made the Expo Park a beautiful and beautiful place, which left a deep impression on people. impression. What is the magic of LED lighting technology? Can ordinary people use LED lighting as soon as possible? What are the obstacles to the commercial application of LED lighting?

Open "First Year of Semiconductor Lighting"

In the history of lighting technology development, the World Expo has always played an important role as a popularizer. At the 1878 Paris World Expo, the incandescent electric lamps made of tungsten wire invented by Edison were exhibited, and the human race ushered in the era of incandescent lamps. In 1939, at the World Expo in New York and Los Angeles, the first practical fluorescent lamp was displayed. Since then, fluorescent lamps have been used on a large scale.

Professor Fang Zhilie from Fudan University participated in the research work of LED lighting at the Shanghai World Expo. In his view, the concentrated application of LED lighting in the Shanghai World Expo Park indicates that the Shanghai World Expo is likely to open a "first year of semiconductor lighting."

According to statistics, at present, 1.03 billion LED chips are used in the Expo Park. LED chips appear in indoor and outdoor lighting, landscape decoration, signage, information display, etc. in the Expo Park. The entire park has become the most concentrated semiconductor lighting in the world. Technology demonstration application area. Among them, about 80% of the indoor lighting sources in the Expo venues use LED green light sources, which is about 90% less than ordinary incandescent lamps.

At the Shanghai World Expo, LED lighting brought visitors an unprecedented visual experience through the interpretation of creative design and technical concepts. For example, the “Happy Street” of the Netherlands Pavilion will decorate the surface of the building with LEDs, and express the joyful atmosphere of the Dutch Pavilion at night through bright and flashing visual effects. The nightscape lighting of the red facade of the China Pavilion was strengthened, and the fairy-tale lighting of the Danish Pavilion used LED lighting.

“In fact, in the 2008 Olympic Games, LED lamps were widely used in venues such as the Water Cube and the Bird's Nest.” Fang Zhilie believes that “the significance of widespread use at the World Expo is more unusual because of the high-tech demonstration significance. Promote the increase in public consumption, drive up the production of manufacturers, and promote the research and development process of the research team."

Energy-saving and environmentally friendly green light source LED

Why LED lighting will become the development trend of future lighting technology? What kind of advantages does this lighting technology have over the past?

Fang Zhilie said that the most common point of LED lighting is LED lighting, which is a kind of semiconductor solid-state light-emitting device. It uses a solid semiconductor chip as a luminescent material. When electric energy passes through the light-emitting diode, a special physical change occurs in the semiconductor luminescent material to cause photon emission, thereby generating illumination light. This kind of illumination has an incomparable advantage over traditional incandescent and fluorescent lamps.

Fang Zhilie showed the reporter a set of data: Since 1962, the semiconductor light-emitting technology has been born so far, the same power consumption, the total amount of LED lamps is 15 times that of incandescent lamps, and twice that of fluorescent lamps. And with the continuous improvement of technology, there is still a lot of room for growth in luminous efficiency, and the growth of incandescent and fluorescent lamps is very limited.

More meaningfully, LED lighting successfully solved the problem of mercury pollution. Fang Zhilie said that whether it is energy-saving lamps, fluorescent lamps, electrodeless lamps, metal halide lamps, high-pressure sodium lamps, a certain amount of mercury should be placed in the lamp tube. Under the action of electric energy, mercury vapor is generated in the lamp tube, thereby exciting Phosphor. However, discarded lamps often release metallic mercury, causing environmental pollution. In LED light-emitting diodes, it is not necessary to put mercury. He believes that LED lighting is a kind of energy source that is both energy-saving and clean. The large-scale application is in line with the concept of low-carbon and environmental protection developed by human society.

The reporter learned that from the Ministry of Science and Technology and the Ministry of Finance to launch the “Ten Cities and Ten Thousand Miles” plan to the “Ten Thousand Miles” high-power LED street lamp industrialization demonstration and promotion project in Guangdong Province, LED is showing its vitality.

Multiple factors hinder LEDs for home lighting

While the industry is optimistic about the development prospects of LED, consumers are also concerned about "when they can use LED lighting."

In this regard, Lu Rongshu, deputy director of the National Electric Light Source Quality Supervision and Inspection Center (Shanghai), believes that the application of LED in outdoor lighting projects is very common, but the application of indoor lighting engineering is in the preliminary stage. He admits that LED is used as a light source for lighting fixtures to enter ordinary people's homes. At present, there are still problems such as immature technology and high prices. In terms of technology, LED lighting also has problems such as low utilization efficiency of light, short service life, and improvement of lighting quality.

"Although LED lamps can achieve high illumination and low energy consumption, this does not mean that the efficiency of LED lamps is high because the overall illumination quality is not high." Lu Rongshu said, for example, "Taking lamps as an example, if With LED light source, it is possible to use 3 watts - 5 watts of illumination (10 watts lower than energy-saving lamps), which saves energy. However, such lamps can only ensure that the vertical illuminance is very high, that is, the light source is very concentrated and illuminating. The angle is small, and the result is that the uniformity, radius and range of the light are limited."

In this regard, he explained that the commercialized 3 watt or higher power LEDs have low luminous efficiency, lower than the luminous efficiency of more than 100 lumens per watt of high-intensity gas discharge lamps, and less than 60 lumens per watt of rare earth. Three primary color fluorescent lamps.

In addition, the glare of LED lamps is too strong, and only a part of them are seen in the eyes at a distance, causing the color of the light to be too glaring. At the same time, although the life of the LED is very long, it is at a low temperature, once it is made into a lighting fixture, the life will drop sharply in a high temperature and closed environment.

In addition, in Lu Rongshu's view, high prices are also one of the important factors affecting the purchase of LED lamps by ordinary consumers. "Using the current technology to use semiconductor light sources for high-power lighting, the initial cost is high, resulting in higher price of high-power LED. At present, the market price of 1W high-power white LED is about ten times to several times the price of traditional light source. ten times."

"In terms of luminous efficiency and price level, it will take time for semiconductor light sources to truly enter the general lighting field to replace traditional light sources in a short period of time." Lu Rongshu suggested, "In the current state of the art, improve luminous efficiency and luminous flux utilization, maximizing To reduce the overall integrated lighting costs, promote its technological advancement and maturity of production processes, and increase the development and promotion of LED indoor lighting products, the era of semiconductor lighting can come early."