Efficient LED street light distribution solution

LED street lamp technology is generally divided into two types: discrete and integrated. Discrete technology uses a single light source of more than 1W to manufacture street lamps, and integrated technology uses integrated chips as light sources to manufacture street lamps. At present, there are many companies using discrete technology. The reason for this is that most manufacturers believe that the heat dissipation and light distribution problems of discrete light sources are easier to solve, thereby enabling LED street lamps to achieve the goal of energy saving and money saving. However, the actual situation is not the case. LED street lamps with perfect heat dissipation and light distribution technology can indeed play a role in saving energy and money. However, both discrete and integrated street lamps face complex heat dissipation and light distribution problems. If they are not solved well: the heat cannot be dissipated, the light distribution loss is too much, which will lead to poor lighting effects, unclear energy saving effects, and even the consequence of dead lights, which gives users the impression that LED street lamps are energy-saving but not money-saving and the technology is not up to standard.

Specifically, semiconductor light sources have always used a cannonball-shaped structure since their introduction. This packaging form has low current and low light output. Now the current of high-power lighting-level chips has reached several hundred milliamperes or even higher. Due to the low photoelectric conversion efficiency, most of the energy can only be dissipated in the form of heat, and high temperature is the enemy of chips. Continuing to use the old method without innovation will not completely solve the light efficiency and light decay problems of LED street lamps.

Discrete light source street lamps also have the following shortcomings in terms of light output: the light source plus the peanut-shaped light distribution loses about 15%, and the glass cover loses about 15%. After the lamp is made, the total light output loses about 30%. The ultimate purpose of the lamp is to illuminate the road surface and serve people. The key lies in the application of the street lamp. The quality of the light distribution is judged by the light effect of the whole lamp and the road surface light effect of the whole lamp. Only by improving the light effect of the whole lamp road surface through light distribution can we determine how much energy can be saved. Road surface light efficiency is an important indicator for evaluating LED street lamps. Although relevant units have not yet issued relevant standards, no matter what street lamp, it must be irradiated on the road surface. Under the premise of total power, the higher the total luminous flux, the better, and the more effective light projected on the road surface, the better. In the light distribution of street lamps, the nominal light source luminous flux of the discrete light source reaches a certain number of lumens, which is unscientific. In particular, after a single light source is made into a street lamp, about 15% of the light becomes glare and light pollution, which reduces the effective light on the road surface of the whole lamp.

So how can we improve the light efficiency of the entire road surface? The design idea of ​​Green Times street lamps is as follows. First of all, start to solve the problem from the light source packaging structure. For chips with the same light emission, the luminous flux of a single package is greater than that of a COB package. But the first thing to consider when making street lamps is the light efficiency of the entire road surface. After COB packaging is light-distributed, it has the following advantages: 1. Good color temperature consistency; 2. Easy to distribute light; 3. Easy to achieve efficient light distribution; 4. Low glare and less light pollution; 5. Easy to waterproof.

Secondly, solve the problem from the perspective of light distribution. Unreasonable light distribution design of street lamps causes too much light loss, which greatly reduces the energy saving effect. In the future street lamps, COB is the future development direction, because under the same conditions, the light efficiency utilization rate of street lamps made of single light sources is about 30% higher. According to the current situation, the effective illumination of the road surface of 120W street lamps has far exceeded that of 250W high-pressure sodium lamps, saving more than 70% energy compared with high-pressure sodium lamps.