Application of LED light source in landscape lighting

LED (Light Emitting Diode) is also called a light-emitting diode. It uses a solid semiconductor chip as a light-emitting material. When a forward voltage is applied to both ends, carriers in the semiconductor recombine and emit excess energy to cause photon emission to generate visible light. The revolution in the third lighting field brought by LED solid-state lighting will become the most effective energy-saving and environmental protection means, and will improve and improve the quality of human life by improving the living environment of human beings and developing new concepts and new models of lighting.

In June 2003, China’s Ministry of Science and Technology, with the support of the “863” program, launched the “National Semiconductor Lighting Project” in the lighting field. In April 2004, the Ministry of Science and Technology determined the focus of work - the development of new lighting industry, and determined that Xiamen, Shanghai, Dalian and Jiangxi Nanchang are the first four national semiconductor lighting industry bases. With the support of the “863” plan and other scientific and technological programs, China has initially formed a relatively complete industrial chain from epitaxial wafer production, chip fabrication, and device packaging integration applications. Zheng You, an academician of the Chinese Academy of Sciences, recently pointed out at the Semiconductor Lighting Industry Development Forum in China (Nanchang) that as a new lighting technology, LEDs will revolutionize the field of lighting with its flexible application, environmental protection and convenient adjustment.

First, the excellent features of LED application urban landscape lighting:

1. High efficiency: LED luminous efficiency is not high, but the spectrum of LED is almost all concentrated in the visible light band, the light efficiency is about 65%, and the monochromaticity is good. It can directly emit colored visible light without filtering, and the light is pure. The incandescent lamp has a visible light efficiency of only 10 to 20%;

2, low energy consumption: LED power is generally 0.03 ~ 1w, through clustering can meet the needs of a variety of modeling, because there is no ultraviolet light in its spectrum, there is no heat, no radiation loss. When color light is needed, its inherent color avoids the time, labor and energy consumption of white light filtering. It does not form light pollution and is a true green light source;

3, safe and reliable: LED single working voltage between 1.5 ~ 5V, working current between 20 ~ 70mA, human contact is not dangerous. The lamp body epoxy resin package is strong against mechanical shock and vibration, and has no harmful substances such as mercury and sodium, and can be recycled;

4, convenient management: LED light source due to the above characteristics, can be centralized control and decentralized control or adjustable control of points and other methods. By controlling current dimming, different light colors are combined to color, and a control circuit is added to achieve various dynamic changes. Its long life of more than 100,000 hours is to reduce the maintenance workload of urban landscape lighting;

5. Social and economic benefits: Compared with traditional lighting tools, LED lighting products, especially GaN-based white LED lighting sources, are small in size, light in weight, good in directionality and resistant to various harsh conditions. Life expectancy and environmental protection have incomparable superiority, which is enough to cause a huge impact on the traditional light source market. With the breakthrough of the third generation semiconductor material GaN and the advent of blue, green and white LEDs, the difficulty and risk of the LED lighting industry are much lower than the microelectronics industry, which can give play to China's comparative advantage. In particular, the chip packaging and lighting system industry located in the downstream of the industrial chain is not only a technology-intensive industry, but also a labor-intensive industry, which can give full play to China's human resources to drive related industries. At present, China's annual electricity for lighting is close to 250 billion kWh. If one-third of semiconductor lighting is used, it can save about 80 billion kWh per year, which is basically equivalent to the annual power generation of the Three Gorges Power Station.

Second, the application of LED light source in landscape lighting in Nanchang City

The relevant leaders of the Ministry of Science and Technology proposed to use the 2008 Beijing Olympic Games and the 2010 Shanghai World Expo as an opportunity to promote the application of semiconductors in urban landscape lighting. The industrialization of semiconductor lighting has significant social benefits, and it has an urgent sense of urgency and necessity. Nanchang City has rapidly emerged in the central inland cities in recent years. As a lighting management department, we cooperated with the transformation of the city, beautification and lighting, and cooperated with the construction of the national semiconductor industry base to develop and promote the application of semiconductor products in urban landscape lighting earlier.

In 2001, we first combined with Dalian Science and Technology Development Co., Ltd. to combine lighting with sculptures with cultural connotations and regional characteristics, using organic semi-transparent panels, translucent FRP, etc. as the framework, clustering LED lights as the main light source, using micro-computer control and other technology research and development. Produced the "Qingshan Lake Pearl" and "Giant Thermometer". From 2002 to 2004, Nanchang Sports Park, Xianghu Lake, Qingshan Lake, Tengwang Pavilion and other places successively produced and installed “winged wings,” “Pearl Lights”, “One Net Love”, “Cangwu”, “Tianwai Guest”, “ "Second Dragon Play Pearl" and other light sculptures, the main light source is basically semiconductor. The splendid colors and changing lights make Nanchang City's night scene more charming, and make Nanchang become a unique "light carving city" in the national city lighting, making the original boring lighting become "the day is a sculpture, is an attraction; The evening is lighting, it is a bright spot." With its unique advantages in semiconductor lighting, “Light Sculpture” has become the crowning touch of urban night lighting.

After more than 20 years of hard work, Nanchang has made great progress in the research and industrialization of semiconductor luminescent materials and devices, and has certain advantages in industry, R&D and talents, and has an important position in China. Its upstream epitaxial materials, midstream chip manufacturing, downstream device packaging and application products have achieved large-scale production, including infrared, red, orange, yellow, green, blue, white LED and other products, with further The basis for mass production and development to high-end products. Among them, the upstream and midstream products of Lianchuang are the largest enterprises in mainland China, and Nanchang University is also in the leading position in the research of semiconductor luminescent materials. Recently, the Ministry of Science and Technology conducted research and demonstration throughout the country. Jiangxi ranks among the four industrial regions with relatively complete semiconductor luminescent materials and device industry chains.

At the end of 2004, we cooperated with Lianchuang Co., Ltd., and adopted a high-starting and forward-looking LED lighting in the landscape lighting of Yudai River in Nanchang.

Nanchang Yudai River, formerly known as the South Drainage Road, was excavated in the 1950s. It has a total length of 12.2 kilometers and is a tree-shaped open channel. It is divided into main channel, west branch, east branch and middle branch. In recent years, due to river blockage and poor drainage, it has become the “Longxugou” in the urban area. In 2000, the Nanchang Municipal Government spent huge sums of money to carry out comprehensive transformation. In addition to the drainage function, the Yudai River also has a landscape function. During this period, Chinese garden art and western garden landscapes are integrated with each other. Waterfront walkways, hydrophilic platforms, recreational green spaces, landscape trees The waterscape is interwoven into another place for people to take a rest. Moreover, the Yudai River, such as the city necklace, activates the lakes such as Qingshan Lake, Xianghu Lake, East Lake, West Lake and Fuhe River in Nanchang City. In 2004, the Yudai River was fully illuminated, allowing the jade belt river at night to fall like a galaxy, reshaping the city's waterscape environment. We focus on the combination of tradition and modernity in the design of Yudaihe lighting, using the "green lighting" method, with white as the main tone, and cross-strait five-level cloth lighting. Under the guidance of the lights, the visitors have the feeling of moving. LED lights are mainly used in the contours of rivers, 14 bridges, and two tunnels. They are arranged in a way of “one light, one bridge, one tunnel, one tunnel and one feature”. Under the tone of white light, through the string lights, line lights, groups, etc. of LED lights, the light distribution characteristics of the semiconductor light source itself are changed to "Hanwa Stream", "Dream into Jiangnan", " Lighting themes such as Xieyang Yanming and Jade Belt Image form a “shared, open, humanistic, artistic” riverside space that activates landscape resources and enhances the value of waterfront areas.

Third, the conclusion

We can see that the current price of LED is generally higher than that of ordinary incandescent lamps and fluorescent lamps, and the biggest obstacle to high-throughput LED devices is still the chip's light-taking mode and high light-efficiency package structure. These need to be solved by research units and manufacturers relying on scale production to reduce costs and technological innovation. At present, the bottleneck of semiconductor light-emitting technology seems to be concentrated on chip manufacturing and device packaging. But in the long run, the development of new materials is a top priority. Although the popularity of semiconductor lighting is not a distant thing, optimists think it is 5 years, and those who are not optimistic think it is 15 years. But our recent development goals should be special lighting, such as landscape lighting, decorative lights and other fields. As the urban lighting design and management department, we hope that semiconductor (LED) can become the mainstream product of our urban landscape lighting as soon as possible, and soon replace the high-power sodium lamp, high-pressure mercury lamp, metal halide lamp and other light sources in the construction and maintenance of street lamps. The night of the city adds light.