Five unique advantages of LEDs for urban night lighting

There are many kinds of light sources used for night scene lighting. We should mainly consider the effect, performance and cost when selecting light sources. When comparing the costs of different solutions, it is not only to compare the price of light sources, but also to compare the comprehensive economic analysis of the whole life cycle. Because some high-efficiency, long-life light sources have higher prices, the number of use is reduced and the operation and maintenance costs are reduced. Economically and technically reasonable.

The traditional light sources used in night scene lighting, such as incandescent lamps and halogen lamps, are bright and have good color rendering properties; however, their luminous efficiency is low and their life span is relatively short, so they are rarely used again. At present, commonly used floodlights are high-pressure discharge lamps, such as high-pressure mercury lamps, high-pressure sodium lamps, and metal halide lamps. These lamps have large power and can realize large-area floodlighting. However, the common disadvantage of these light sources is that it takes a certain period of time for the lamp to work stably after being lit, and if the lamp is unexpectedly extinguished, the lamp must be cooled before it can be restarted. In addition, these lamps are not easy to achieve dynamic effects such as changes in light color, although if coupled with color filters, light color changes can also be achieved, but this will greatly affect the system efficiency.

As a new force in the light source, LED's light-emitting method is very different from traditional light sources. It uses the recombination of electrons and holes in the semiconductor PN junction to emit light. Different lighting methods determine the essential difference between LED and traditional light sources, and also determine that it has its own unique characteristics.

First of all, the LED is small in size, and the size of a single high-power LED chip is generally only 1 square millimeter. With the outer packaging material, the diameter of an LED is usually only a few millimeters. Multi-chip mixed-light LEDs integrate multiple LED chips. The size is slightly larger. This brings a high degree of flexibility in the design of lighting fixtures. LED fixtures can be made into point, line, or surface light sources as required. The size of fixtures can also be customized according to the characteristics of the building structure. A good realization of the light does not see the effect of the lights. More and more modern buildings are adopting new materials such as glass exterior walls, which makes the traditional external light lighting method gradually replaced by internal light transmission, and LED is an excellent choice for internal light transmission. Helps reduce light interference and light pollution problems.

Second, LED colors are rich, and the emitted light is monochromatic. Monochromatic LED emits better monochromaticity. This is determined by the light emitting principle of the LED chip. Using different light emitting materials, monochromatic light of different colors can be obtained. In addition, based on the blue chip, Yellow phosphor, you can get different color temperature of white LED, or by the red, green, and blue monochrome LED chip packaged in a LED, using the corresponding optical design to achieve three-color light mixing.

Third, LED has a long life, fast response, and can be switched repeatedly. The life of high-power LEDs can reach more than 50,000 hours under normal operating conditions. Moreover, the response of LEDs is very fast. In addition, we can repeatedly switch LEDs without adversely affecting their lifetime or performance. This is very different from traditional light sources. Ordinary incandescent light bulbs are rapidly degraded if they are repeatedly turned on or off. Ordinary fluorescent light bulbs can cause loss of electrode-emissive materials at each switch. Frequent switching can also result in rapid drop in lamp life. For a high-pressure gas discharge lamp, repeated switching also has a very adverse effect on the electrodes of the lamp. Moreover, this type of light source cannot achieve a hot start, that is, after the lamp is turned off, it needs to be cooled down for a certain period of time to start again. . Therefore, for some lighting effects that require repeated switching operations, LED has a unique advantage.

Fourth, LEDs can achieve rapid and varied light color changes. As described above, the red, green and blue monochromatic LED chips are packaged together, and the emitted three-color light is mixed to obtain white light. If we control the red, green and blue chips separately, we can change the proportion of the three-color light in the output light so as to achieve the change of the entire LED output light color. As a result, an LED is just like a palette, and different colors of light can be blended according to different needs. This is something traditional light sources cannot do. LED response speed is fast, easy to control, so you can achieve rapid and diverse changes in light color, we can use this feature of the LED, to construct a number of dynamic effects.

Fifth, LEDs can be used to build various patterns. Because of the small size, solid structure, and short response time of LEDs, we can use LEDs to build certain graphics; then we can combine these graphics to achieve some design effects. Now, in the streets and shops of the city, we can all see a lot of flat patterns or three-dimensional graphics built by LEDs. These patterns and graphics can achieve very dazzling effects. In addition, we can carry out large-scale centralized control of the LED and use the entire building exterior wall as a dynamic screen display.