The most appropriate range of LED lighting color temperature should be close to the sun, natural white color temperature range is the most scientific choice; low light intensity of natural white light, white light can reach the incomparable light of other unnatural effect; the most economical road brightness within the range should 2cd/m2; improve lighting uniformity and eliminate glare total energy consumption is the most effective way. Keywords LED, color temperature, natural white, high-pressure sodium lamps, solar spectrum, CRI, CIE standard illuminant D65, the average brightness, illumination, display capabilities, the total illumination uniformity, glare, the threshold increment, in the introduction of Energy saving incandescent lamps, high pressure sodium lamp, people were lighting color temperature of no choice but to silently accept and adapt. However, you can choose to enter the color temperature of LED lighting times, choose what kind of LED lighting color temperature, it becomes an urgent need to clear it with a clear view of the problem. This is a matter of joint event with the quality of lighting, we can not afford sloppy response. There is a saying, borrowed European hobby tend to select 2700-3200K color temperature range. It is said the Europeans prefer the color temperature range. In this regard, I have a different view, move to discuss with you: 1, the human brain and identification of things through the eyes of the human brain response mechanism to get images of things outside the first reaction is that the images obtained with the original stored in memory in the brain compared to the image information and identification, then immediately make the appropriate response action. If the information obtained with the original image information stored in the closer, the faster identification, the more agile response. If the driver at night with natural light during the day and the low color temperature difference between the farther light on the identification of images acquired more effort to identify the slower, the slower the response speed to follow. Slow down the response speed of 0.1 seconds is enough to make the results suddenly sudden increase in accident rates. To compensate for this difference between day and night lighting color temperature caused by defects, the only way is to increase the lighting intensity, color temperature to enhance the identification of low speed, which means increased energy consumption. Evolved from animals to humans tens of thousands of years long process of human life has always been under the sun's natural light, engaged in all production and social activities. Long natural selection and evolution, making the human eye to adapt to the color temperature range is the most natural white color temperature range of the Sun (5500-7500K). The human eye in the color temperature range of dynamic and static object recognition strongest; in this color temperature range, the response of human things, the ability of the outside world and most agile. Because, people inside the brain memory repository of information stored in the object image, mostly in the natural formation of white light irradiation. Therefore, the most appropriate LED lighting color temperature range, should be close to the sun, natural white color temperature range, is the most scientific choice. 2, the Europeans prefer the low color temperature of biological, geographical reasons, then, why Europeans like to do a low temperature? It has its ethnic and geographic reasons. Europeans race for the white skin, white light will make people look pale white skin. Even exaggeration, like the color of the dead, so they prefer warm colors are very natural. But we are yellow ah, the sun naturally white color does not make us look pale. Also, most of Europe is located in the high latitudes, low temperatures of the area, which also contributed to their preference for warm geographical reasons. However, we are located in the four seasons of temperate zones, not the long cold winter, too warm to follow the Europeans choose the color, no need of a bit. 3, the yellow light rain and fog penetration of suitable applications there is a saying that a low color temperature of the yellow light rain and fog the ability to penetrate better, so you should select it. We do not deny that yellow light penetration of rain and fog better than the white light of this fact. However, we should understand that a lot of road lamps, is most of the time working in sunny conditions, rain and fog weather, after all, the proportion is relatively small. Choose to adapt to the warm weather, warm rain and fog lamps, is it overwhelming and confusing? In specific situations, such as foggy port occasions, low color temperature lighting is the choice of a reasonable approach. Ordinary road lighting, should be chosen close to the sun or the natural white color temperature range, is both science and energy-efficient practices. Above, we identified only from the human brain's response mechanism to explain the lighting and color temperature of white light should be chosen close to the natural reason. Here, we further from color-rendering index of the point of view, to do further analysis on this point. 4, natural white light of high color rendering index of the natural advantages of sun, white light, refracted through the lens of Mitsubishi, can be decomposed into red, orange, yellow, green, green, blue, purple and continuous spectrum, wavelength 380nm-760nm seven light. Sun contains the full continuum of natural white light visible spectrum. The reason why the human eye can see objects because the divergence or reflected from the object's light into our eyes and perception. The basic mechanism of light is to light exposure to the object after the object of absorption and reflection, and reflection from the outer surface of the object into the eyes and let the people perceived the object's color and appearance. However, if this light beam illumination of a single color of light is, then, we can see will only be with the colors of the objects. It goes without saying, if the beam of light is complete with a continuous spectrum of light, then, objects appear out of the face, will be with us in the natural white light observed, the same vivid color content and appearance. This would have led to a color rendering index (Ra-color rendering index / CRI) concept. The sun's natural white light with a full continuous spectrum of white objects in the natural sun exposure, due to the combined effect of colored light, which can show the true color and appearance of the object. So we put the sun's natural white color rendering index is defined as 100, 100 per cent means that it can show the true color of the original object. This is according to the human eye in the sun, natural white light, the observed color of the object as a benchmark, and develop standards. Strictly speaking, the standard white light in nature, each one seemingly ordinary objects flat contour, can be decomposed into the standard color plate shows the variety of color. That is, if we use the standard white to light in any color of an object, we see its outline of the most "dense" clear. However, if monochromatic, or color is not very rich, natural light deviation from the standard solar lights to light the object, then its contour, it will because the light source of the "inherent" and does not seem "thick" clear, even fuzzy . Dominant spectrum of traditional high pressure sodium and for the 589.2nm 589.6nm, are two very close to the line, close to monochromatic light. High pressure sodium color index is only 20-30. Therefore, various objects under high-pressure sodium lamps, will appear blurred. To make people see the real original object, we need to strengthen the intensity of lighting to be able to make eye to see objects in the real original demand. Enhanced illumination, it means increased energy consumption. Even so, the object observed under sodium clarity and true color is natural white light can never reach the true effect. This is a lot of night shoppers, only to find during the day and night to the items purchased, not their favorite color, Dahushangdang, the initiator, it is a low color rendering index of light that were there. Sodium street lights under the night market weakness, low color, it is like night market must first pay attention to the point oh. 5, low color temperature, low color rendering index of the price of sunlight exposure to the earth from morning till night, not every time we feel the sunlight, it is definitely natural white. Because it is also subject to varying thickness of the absorption and refraction of clouds, reflection interference, forms a natural white light of various spectral composition and the ratio will change. Morning and evening sunlight, but also subject to heavy cloud cover, light refraction angle and the serious impact of the golden sun and thus this time period, its color index has been away from the 100, even more can not be regarded as a natural white light. By Kevlin color Wending Yi, 2800K-10000K color temperature of sunlight are part of the range, this is the broad sunlight of color Wen Dingyi range. However, only the color temperature of 6500K light (also known as D65) is set at the standard white color temperature, it is the CIE standard illuminant D65. 6500K color temperature of light spectrum contained the most complete, closest to the natural white light. Farther off the natural white color temperature light source, its color rendering index lower. Obviously, the lower temperature of the LED, the color-rendering index white LED will be more than the lower. In the low color-rendering index of light to see objects in the real original, you need a higher light intensity to compensate for the lack of color-rendering index. This means that people have to increase the light energy input, in order to get close to natural white light shows the true original objects. Practice has proved that, using close to natural white light, only need far less than other light source illumination, you can allow people to truly perceive the true color and original objects. Illumination means low energy input, it means that energy. Therefore, we recommend close to natural white light as our light sources. 6, low color temperature LED light intensity decreased cost of the LED package of technical reasons, a mixed red and yellow pigments of the LED, the light fades faster than the white LED, that the luminous intensity must decrease faster than the white LED . Compensate for this loss of light intensity decreased the cost of the assembly is to increase the number of LED lamps, which is meant to increase the cost and energy, which is very frustrating results. 7, the era of the inevitability of change lighting standards lighting ultimate goal is to get people to get on the moving and static objects observation of the real image clarity. Today, there are color-rendering index of 70 - 90, close to the sun, natural white LED lamps appear, is what we improve lighting quality and reduce energy consumption of a good opportunity. High pressure sodium color-rendering index of only 20-30. In the era of its leading lights system, in order to achieve access to the object in its light and clarity discerning observation, it can only increase the value of the illumination means to try to achieve their goals. Ministry of Construction of "Urban road lighting deSign standards", is based on a low color rendering index of the sodium-driven light source in the context of the development of these standards is nothing wrong with the original. However, to the high color rendering index of the LED for the lighting conditions, this standard becomes too high. Because, in the high color rendering index of the LED light source, to obtain the true image of the object identification and observation of clarity, only far less than the high-pressure sodium illumination required standards. According to our years of experience, just less than the Ministry of Construction, "Urban road lighting design standards" 30% of the illumination intensity, the same can be achieved with high-pressure sodium lamp, or even better identification and definition of the lighting effects. Using high-pressure sodium lamp with the same standards to regulate the LED illumination light source, means the unnecessary waste of energy. High-intensity LED lighting, LED or even lead to
