In the application of LED street lamps, there is a problem of configuring lighting projects based on the "power" indicators of lamps. However, if you do not correctly grasp the overall light efficiency and utilization of LED lamps and sodium lamps, it is easy to cause insufficient luminous flux or excessively bright ground. This is because what we need is the brightness of the ground. Based on the characteristics of the ground material, we can get the illuminance of the ground, get the required luminous flux according to the illuminance range, and reverse the luminous flux of the lamps according to the utilization rate, maintenance factor, and arrangement of the lamps. After obtaining a certain luminous flux, we can calculate the power based on the efficiency of the lamp. If electricity is used directly, many of the above uncertain factors will affect the suitability of electricity selection.
The lighting design has no safety and effect indicators, such as Lav, U0, UL, TI, SR, I80, etc. It is required to evaluate road lighting, but there are safety and lighting effect indicators. Lav is an indicator that affects driving safety and capacity; U0 is an indicator that affects driving safety and capacity; UL is an indicator that affects driving safety; TI is an indicator that affects driving safety ; SR is an index that affects driving comfort; I80 is an index that affects driving comfort. It should be noted that the brightness is related to the luminous flux/ground reflection coefficient/observation angle/projection surface size. Illuminance is the luminous flux received per unit area, which does not completely correspond to the light required by the human eye. Drivers usually look at the road from 60 to 160 meters away and see the brightness reflected to human eyes. The lighting index cannot replace the brightness index. The conversion between illuminance and brightness, the brightness coefficient Q, is non-linear along the driving direction. The more uniform the illuminance, the more uniform the brightness is not necessarily.
Therefore, UE cannot replace UL. From the light distribution effect based on illuminance and brightness, based on the light distribution of "high illuminance uniformity", the measured UL is less than 0.7, and there will be obvious zebra lines on the ground; according to the "high total uniformity based on brightness", measured The UL is greater than 0.7. Comparing the lighting effects of the sodium lamp and the LED under the same Ul, the light distribution characteristics of the sodium lamp shade determine more stray light, and the more accurate light interception effect of the LED makes the stray light less. Stray light can fill up a certain lack of brightness in dark areas, or make brightness changes less dramatic. Compared with white light LED, the color of sodium light source after light attenuation is closer to the asphalt pavement, the color contrast of sodium lamp is lower, and the ability to recognize light and shade in the environment of sodium lamp is lower. Therefore, under the same Ul, the sodium lamp and the LED light source are more likely to produce zebra crossings. In addition, it is found that TI 10% is easily exceeded, and TI 20% glare is not disabled. If it is not controlled, there may be a disability trend or an increase in the degree of "disability". I80 is greater than 200cd/m2, and the lighting area of the lamps is small (such as cobLED street lamps), which is easy to cause uncomfortable glare.