Globally promote low-carbon life, LED has become a new generation of environmentally friendly light source. At present, China has included semiconductor LED lighting in the medium and long-term science and technology development plan, and has initially formed an industrial chain of epitaxial wafer production, chip preparation, package integration and LED application. In addition, the state pays attention to the promotion of the LED industry. On the occasion of the first LED theme park in Guangdong in the middle of October, the “Guangdong, Hong Kong and Taiwan LED Industry Design Summit Forum†was held concurrently. Professor Zhao Haitian from the School of Architecture and Urban Planning of Shenzhen University talked about it. When developing LED street lights, it is said that independent innovation is particularly important under current opportunities. He analyzed the feasibility of independent innovation through the form of question and answer.
Imitation and simple replacement are the dead spots of LED street lights
At present, LED application and research and development mainly use LED and traditional light source for simple replacement. Almost all LED manufacturers follow the design idea of ​​traditional street lamps, and pursue tens of watts and hundreds of watts of high-power LED street lamps to meet current HPS lamps. The modeling and installation methods are identical or compatible, and the current LED street lamps and installation methods are almost all designed and manufactured according to the "snake head (flat snake head) lamp" suitable for the HPS light source, instead of the LED lighting law as the starting point for research and development.
Analog, counterfeit, conventional lighting street lamps used in a variety of "snake head" shape production, from the domestic manufacturers involved in the production of LED street lamps, most of them have not produced street lamps, the specific technical requirements for street lamp production is relatively vague, Mutual reference imitation, mostly in the shape of conventional traditional "snake head" shape, the rectangular weight and wind resistance of LED street lamps affect the retrofit installation of street lamps, and it is more difficult to compare with conventional gas discharge lamp lamps in optical distribution and maintenance requirements. In particular, the direct use of the reaction is strong, which brings difficulties to the application.
In the forum, Zhao Haitian believes that the first thing to consider when dealing with HPS light sources with LED light sources is how to deal with glare problems. Glare is caused by the excessive brightness of the lamp or luminaire directly entering the field of view. The severity of the glare effect depends on the brightness and size of the source, the position of the source within the field of view, the observer's line of sight, the level of illumination, and the reflectance of the room surface. And many other factors, the brightness of the light source is the most important. No matter whether it is high power or low power, if the light distribution process is not good, it is glare. Now, in order to achieve the light effect, many LED lamps use a transparent mask, and the effect is very poor.
The second is the problem of invalid lighting. At present, most public spaces such as corridors, walking ladders, parking lots, toilets, elevators, and roads. It is usually illuminated by lamps for a long time, and sometimes these places are empty, and the electricity is consumed in vain. Therefore, the most energy-saving technology is not on the wattage of the lamp, but how to make the lamp smarter and more human. When no one is using it, you can enter the "sleep" state, and some people will slowly wake up.
In addition, it is a matter of visibility. The zebra crossing effect and the environment in which the air pollution is severe, rainy and foggy, causing the light to be bright on the ground, therefore, the most important main attack is to reduce the energy consumption without affecting the ultimate goal of illumination visibility. The direction is to try to improve the overall uniformity of the lighting. With good total illumination uniformity, the average brightness of the illumination can be appropriately reduced, so that the same recognition and recognition of the visual effect of the object can be achieved, and at the same time, the purpose of energy saving and consumption reduction can be achieved.
The facts show that replacing the HPS light source with an LED light source is not a change in illumination mode, and it is impossible to solve the problem of the high-level illumination mode.
LED street lights new problems and independent innovation
What are the new problems with LED street lights?
Zhao Haitian also said that there are still new problems in LED street lights that need to be solved.
Light effect problem. Insufficient perception of road lighting requirements, scientific point light source optical light distribution difficulties and neglect of the importance of color temperature in road lighting, easy to cause glare, zebra effect and in the environment of serious air pollution, rain and fog, causing the light to shine The ground is not bright enough.
cooling problem. Whether it is a single point or a multi-point source of LED street lights, there is a problem of heat dissipation. A street lamp with 250W high-pressure sodium lamp, because of the mature technology, the heat dissipation is very good. Even if it works for 5,000 hours, the light decay is still small. Under the same conditions, the high-power LED street lamp is difficult to solve due to heat dissipation, and the light decay is large. The luminous efficiency will drop to 30%. If you want to increase the light efficiency by increasing the voltage and current, it is easy to cause the LED chip to be damaged.
Life problem. LED driver power supply instability is the industry consensus, in fact it is dragging the LED lighting industry hind legs, because the drive power is an important part of the LED street light, its failure will lead to the failure of the whole lamp. Due to the harsh environment of outdoor work, the life of some components of the power supply becomes the bottleneck of the life of the driving power source or even the entire street lamp.
Weight problem. The high cost of LED street lamps is not conducive to popularization. Although the heat dissipation problem of LED street lamps has been initially solved, the excessive price and overweight lamp heads still hinder the popularity of LED street lamps.
What is the independent innovation of LED?
The first is the research of technologies such as upstream chips in LEDs. As the world's largest lighting market, China's LED mid-stream technology link has become a serious injury. Many domestic manufacturers lack core technologies, and their investment in innovation and research and development is very small, leading to the long-term monopoly of LED key technologies. Without technology, there is no way out. It is a stupid effort to invest in a frenzied irresponsible mass production movement, resulting in negative effects such as overcapacity and poor quality.
The second is the study of LED related standards. As a new lighting product that is attracting attention, how to use the LED light source to meet the application requirements is a major issue facing LED lighting products. To solve this problem, we should begin to understand the basic principles of the luminaire standard from the understanding of the existing luminaire standard system. When we look at the characteristics of the LED luminaire from a scientific perspective, we will understand that the existing luminaire standard has covered the LED luminaire. Due to some characteristics of LED lamps, additional requirements for LED lamps are required, and special requirements for LED lamps are required.
What restricts independent innovation?
Impetuous is a natural enemy of independent innovation, too quick and quick.
Impetuous performance in terms of products. At present, LED application and research and development mainly use LED and traditional light source for simple replacement. Following the design idea of ​​traditional street lamp, the LED light source can simply replace the traditional light source, and the advantage of LED can not be played well.
Impetuous performance in research. Nowadays, relying on the technology development model of the company alone, it is difficult to adapt to the ever-changing market environment. It must be integrated with all enterprises and institutions in the upstream and downstream of the industry to jointly establish an "innovation chain" for R&D and even the entire industry. Technological innovation.
Impetuous performance in the media. Many media can't really grasp the development trend of the industry. They like to exaggerate the development of the industry, so that enterprises in the industry can not really understand the development of the industry and make wrong judgments.
Conclusion: The LED industry is a strategic emerging industry. There is a long way to go. When promoting the LED industry, the results of the action are important, but the thoughtfulness before the action can not be ignored. The LED industry, especially the promotion of LED lighting, is a step forward for progress, not for promotion. In the process of industrial development, there will naturally be difficulties in many aspects such as system, concept, technology, market, etc. At this time, it is necessary for enterprises to make their own efforts, and more attention needs to be paid and supported by the government, academic circles, etc., so as to promote "detailedness". Focus on the source, solve the problem from the source, and promote the LED industry step by step.
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