Analysis of the 5 unique advantages of LED in urban night lighting

There are many kinds of light sources that can be used for night scene lighting. When choosing a light source, we should mainly consider the effect, performance and cost. When comparing the costs of different solutions, we should not only compare the price of the light source, but also conduct a comprehensive economic analysis and comparison of the entire life cycle, because some high-efficiency and long-life light sources, although more expensive, are economically and technically reasonable when the number of uses is reduced and the operating and maintenance costs are reduced.

Traditional light sources used in night scene lighting, such as incandescent lamps and halogen lamps, light up immediately and have good color rendering properties; however, their luminous efficiency is low and their lifespan is relatively short, so they are rarely used. Currently, the commonly used floodlighting light sources are high-pressure discharge lamps, such as high-pressure mercury lamps, high-pressure sodium lamps and metal halide lamps. These light sources have high power and can achieve large-area floodlighting. However, the common disadvantage of these light sources is that it takes a while for the lamp to work stably after being lit; and if the lamp goes out accidentally, it needs to wait for the lamp to cool down sufficiently before restarting. In addition, these lamps are not easy to achieve dynamic effects such as light color changes. Although light color changes can be achieved if equipped with color filters, this will greatly affect the efficiency of the system.

As a new force in light sources, LEDs emit light in a completely different way from traditional light sources. They emit light by utilizing the recombination of electrons and holes in the semiconductor PN junction. The difference in the way they emit light determines the essential difference between LEDs and traditional light sources, and also determines that they have their own unique characteristics.

First of all, LED is small in size. The size of a single high-power LED chip is generally only 1 square millimeter. With the external packaging material, the diameter of an LED is usually only a few millimeters. Multi-chip mixed light LED integrates multiple LED chips and is slightly larger in size. This brings high flexibility in the design of lighting fixtures. LED lamps can be made into point, line or surface light sources as needed, and the size of the lamps can be customized according to the characteristics of the building structure to better achieve the effect of seeing the light but not the lamp. Modern buildings are increasingly using new materials such as glass exterior walls, which has gradually replaced the traditional external projection lighting method with internal light transmission lighting. LED is an excellent choice for internal light transmission lighting and helps reduce light interference and light pollution problems.

Second, LED has rich colors and good monochromaticity of the emitted light. The monochromaticity of the emitted light of the monochromatic LED is good, which is determined by the light-emitting principle of the LED chip. Different luminescent materials can be used to obtain monochromatic light of different colors. In addition, on the basis of the blue light chip, with the yellow light phosphor, white light LEDs of different color temperatures can be obtained , or by packaging the red, green and blue monochromatic LED chips into one LED, the corresponding optical design can be used to achieve the mixing of three-color light.

Third, LEDs have a long lifespan, fast response, and can be switched on and off repeatedly . The lifespan of high-power LEDs can reach more than 50,000 hours under normal working conditions. Moreover, LEDs respond quickly, and we can switch them on and off repeatedly without causing any harmful effects on their lifespan or performance. This is very different from traditional light sources. If ordinary incandescent lamps are switched on and off repeatedly, their lifespan will decrease rapidly; for ordinary fluorescent lamps, each switch will cause the loss of electrode emission materials, so frequent switching will also cause the lifespan of the lamp to decrease rapidly. For high-pressure gas discharge lamps, repeated switching will also have a very adverse effect on the electrodes of the lamps. Moreover, this type of light source cannot achieve hot start, that is, the lamp needs to cool down for a certain period of time after being turned off before it can be started again. Therefore, for some lighting effects that require repeated switching operations, LEDs have unique advantages.

Fourth, LED can achieve rapid and diverse changes in light color. As mentioned above, by packaging red, green and blue monochromatic LED chips together and mixing the three-color light emitted, white light can be obtained. If we control the red, green and blue chips separately, we can change the proportion of the three-color light in the output light, thereby achieving the change of the output light color of the entire LED. In this way, an LED is like a palette, which can mix different colors of light according to different needs, which is impossible for traditional light sources. LED has a fast response speed and is easy to control, so it can achieve rapid and diverse changes in light color. We can use this characteristic of LED to construct many dynamic effects.

Fifth, LED can be used to construct various patterns. Due to the small size, strong structure and short response time of LED, we can use LED to construct certain graphics; then combine these graphics to achieve certain design effects. Now, in the streets and alleys of the city, in the shops and stores, we can see many flat patterns or three-dimensional graphics constructed by LED, which can achieve very dazzling effects. In addition, we can centrally control LED on a large scale and use the entire building exterior wall as a display screen for dynamic pictures .