Light Distribution Design Of LED Road Light

The light intensity distribution of light source in each direction of space is light distribution.The light distribution design of LED road light is order to make the light projected to each area of the illuminated road as far as possible, and obtain the light distribution that meets the requirements of road lighting.Whether the light distribution design of LED street light is accurate and in place is one of the key factors whether it can replace the traditional street light.The research on LED street light distribution is of great significance to the system design of LED road lighting in the future.

Shape characteristics of lighting distribution of LED road light

In road lighting, if there is no light distribution design for light source of LED street lamp,the light shape illuminated on the road surface is a large circular light spot, and some light will scatter outside the road surface and not be used.As shown light distribution diagram a below:

In order to meet the requirements of brightness , illumination and uniformity for the road surface, and make most of the light distributed on the road surface as far as possible,so as to improve the utilization rate of light and reduce unnecessary waste, it is usually necessary to do light distribution design for LED street lamps.The light type or light spot formed by the light output from LED street lamps irradiating on the road surface takes the rectangular as the best.As shown diagram b below:

Light distribution curve of LED road light

The spatial distribution of luminescence intensity is usually called the light distribution curve.Under the road light, the light intensity should be minimal, and with the increase of elevation Angle θ, the light intensity I increases. The function relation is as shown in the diagram below:

Due to the complexity of optical design, it is difficult for the shape of light distribution to completely conform to the function relation, so the projection range of θ Angle can be reduced and the distance between lamps can be reduced to obtain uniform illumination.In general, it is hoped that to achieve wide Angle "batwing" shape lighting after light distribution design.The ideal light distribution curve of a single led lamp fixture for road lighting is shown in Figure below:

Light distribution scheme for LED road light

The light distribution scheme for LED road light should be carried out on the basis of the requirements for road lighting, and the glare control and environmental coefficient should be considered at the same time.For road lighting, luminous efficiency and light distribution curve are two important parameters. At present, light distribution schemes for LED street lamps mainly have the following basic forms:

Firt light distribution design of LED road light

In the manufacturing process of power LED, the lens process is adapted during sealing can improve the light efficiency, reduce the light output loss and change the light output characteristics.The sealing lens technology of LED has a certain relationship with the primary light distribution design of high-power LED street lamps.

The light intensity output curve of a single LED can be transformed into a "batwing" shape by using the LED light distribution encapsulated by a double-headed lens, so as to further realize the "batwing" shape light distribution of the overall light intensity output curve of the whole street lamp.

Secondary light distribution design of LED street lamps

The output light characteristic is further changed by using the lens or reflector for the high power LED in LED street lamp, that is, the secondary light distribution of LED road light.No matter what kind of technical means or scheme is adopted, for the light distribution design, as long as the light output characteristics meet the standard requirements of night road lighting,the technology or scheme has good use value.Light distribution scheme often needs to be combined and repeatedly designed to meet the standards of road lighting.

At present, the power white LED is developing towards the direction of single-chip high power. Due to the bottleneck of chip heat dissipation, the single-chip high power LED with multi-chip combination package has relatively difficult in heat dissipation and low light efficiency.

The third light distribution design of LED road light

On the basis of the first and second completed light distribution of high-power LED, the third light distribution of LED road light is realized by superposition and spatial arrangement of multiple LEDS (unit modules), so as to meet the requirements of average brightness, average illumination and uniformity of road lighting.

At present, the biggest characteristic of led street lamps is the function of directional emission.Led street lamps with power performance are almost equipped with reflectors, and the efficiency of this reflector is significantly higher than that reflector of conventional lamp.Road lighting using LED street lamps should try to maximize utilization of the LED characteristics of directional light emission, so that the each LED light can directly illuminate the road surface of each area, and then use lamp fixture reflector to assist light distribution, so as to achieve a very reasonable comprehensive light distribution of road lights.

In a word,light distribution design of led road light is very important for the work performance of lighting lamps, which will affect the irradiation area of street lamps, and whether the illumination is uniform, whether there is a yellow circle and other issues.If buying road lighting products with unreasonable light distribution,there will be many troubles brought to customer.It is recommended that to require that the manufacturer show the light distribution diagram and turn on the light for detection when buying.