New high efficiency light source, especially white light source (applicable to general lighting) to reduce the development of lighting power consumption has very important role, because it can reduce power consumption growth speed, and reduce the cost of the new power network capacity, reduce energy consumption and reduce emissions into the atmosphere of the greenhouse gases and other pollutants.
12v led light bars, especially white LED light, because of its and the traditional light source are the theory and compared the superiority of the real, well received by the professional people of all ages. It has also to develop the world for lighting a new technology, and the illumination energy conservation design provides more choice. The author on the performance of the current situation, LED a brief introduction and analysis.
The advantages of the LED
As mentioned above, as a kind of cold light, LED with many traditional light sources can match advantage:
(1) don't need air, do not use glass shell, impact resistance, vibrate resistance, not easy and broken, easy to transport.
(2) The light source unit Lesser, make more flexible cloth lamp, and be able to better achieve lighting at night "see light see light source" the effect.
(3) can well control of light spectrum, which can be used for the museum and galleries local or focus lighting.
(4) compared with traditional light source in the higher the luminous efficiency, theoretically led the luminous efficiency of more than 200 lm/w, thus has the potential of energy saving is huge.
(5) to live longer, laboratory lifetime 100000 h, switch times are over 100000 times, and start at a very fast rate.
(6) can through the control of semiconductor glow of semiconductor materials with the size of the picture ban, which sends all the light color, and chroma higher.
(7) light source added in the Mercury, be helpful for protecting the environment, can be recycled.
(8) LED has the very strong directional, which can better control the light, and improve the system of lighting efficiency.
(9) use the low voltage dc, has the load of small, weak, and the advantages of security interference.
(10) without the light of the ultraviolet ray, be helpful for human body health, and do not attract mosquitoes.
LED application technically difficult problem
In theory the luminous efficiency LED can be as high as 200 lm/w above, and the existing white LED is only 85 lm/w or so, and energy-saving fluorescent lamps, there is still a gap compared, and its price and the traditional light than a great disadvantage. So how to as soon as possible the advantage of LED display true will become the relevant employees must now face of technical problems. But to really develop a whole new semiconductor lighting era, we also the following several aspects to conquer technical problems and further standardize semiconductor lighting market.
1, LED chips
The chip is LED core, its internal quantum efficiency directly affects the efficiency of high density led strip. The radiation compound rate will decide the chip the size of the heat production. Can say only produce has good quality LED chip, just may have the superior performance of the LED light source.
In order to be able to try to improve efficiency and reduce internal quantum no radiation compound rate, mainly from the two aspects to improve the quality of chips, also is to choose a reasonable chip structure and control chip density.
The structure of the LED chips has single heterogeneous structure, double heterostructure and quantum well structures, etc, it to the luminous efficiency has a very big effect. At present is the most widely used and most efficient chip structure which is quantum well structures, for LED is concerned, the extension of the substrate and the lattice constant and heat coefficient whether matching, extension of preparation technology, etc, will directly influence the density of the grid. These may be in some conditions, especially for iii-nitrogen shine may favor, but for most case, because the existence, will shorten the chip of continuous operation life, reduce the density and light output reduction carriers, and may be no radiation recombination center.
Therefore, how to choose reasonable chip structure, understanding of the shine of grid work led chips influence mechanism so as to better control the generation of adverse, also become the current what we must face one of the important topics.
2), encapsulation and heat dissipation
The packaging must be LED to deal with: should try to reduce the light in LED internal total reflection, increase the substrate substrate reflectivity, so that as far as possible much light penetrates out, improve the external LED quantum efficiency, also is to increase the luminous efficiency LED. The existing technology including substrate dissection technology (lift-off), flip-chip technology, etc.
Also should choose a new type of packaging material, to reduce because ultraviolet ray and cause packaging materials such as the color of yellow bring change.
The problem is the effect of heat LED LED drive current ascending an important factor.
LED chips node temperature ta directly affect the life of LED, therefore LED cooling capacity strength has limited the size of the LED power, and the installation and use of the temperature of the environment.
3), white LED
How can the preparation with high color rendering, high luminous efficiency of the white LED, is LED to general lighting is widely used in a premise. For White LED speaking, luminous efficiency, color rendering and cost are decided it in the lighting of the market competitiveness. The preparation methods of white LED can be divided into three types: red, green, blue (RGB) chip combination white light technology, single chip and phosphor synthesis technology and white light mocha direct growth of the active region more white LED technology.
Several technology, by contrast, is on a study stage of exploration in addition to the growth of the active region mocha direct more white led technology outside, although RGB led with high efficiency light type, good color rendering and other advantages, but the performance of the three different, so they drive current or temperature because of the influence of factors and produce color drift, affect illume stability.
And for single chip and phosphor synthesis white light technology, and divided into the blue chip and yellow phosphor type and uv LED and led a phosphor RGB LED. Blue yellow LED lack of red, so have a difficult to high show color of white light (r85), also will produce the halo effect (there are directional LED out light and phosphor scattering light angular distribution); The ultraviolet light is add RGB LED the phosphor LED overcome these disadvantages, become the current performance is good a white LED.
With its huge LED the potential of energy saving and good lighting performance we opened a new technology. But it is also facing mentioned many technology and puts forward the system barrier that the price of the product still very expensive, performance vulnerable to external environment condition the influence, but also because of crystal properties are still not fully mature, restricts the LED to further promote the. Of course all this can't stop a new arrival of the era of lighting. LED belongs to the 21 st century green light source. But it may be more to belong to the future, just as the United States department of energy 2002 wrote the leds for general illumination "in the expected, LED to 2012 years to replace the fluorescent lamp in lighting.
In our lighting design process, we should be in a rational approach to treating LED application, should be truly understand the LED performance premise, according to the conditions of the environment. Reasonable choose to use LED to really create an energy saving and high quality lighting light environment.
