Focus analysis of road luminaires using LED light sources

As a novel solid lighting, LED has a production process and almost no pollution, no vibration, easy to achieve 0~100% continuous dimming, can work under safe extra low voltage, can work continuously on switch flash The working state and its light output are directional and many other unique advantages. In recent years, its remarkable improvement in light efficiency and light color has enabled it to enter commercial applications.

However, due to the influence of China's planned economic industry layout and the lack of expertise in LED and the comprehensive knowledge of lighting appliances in the practitioners, there has been no application for the design and application of LEDs . Unreasonable and unqualified application products. The following is an analysis of the existing problems of LEDs used in road lamps, and also gives ideas and examples for solving problems, for the reference of the majority of peers.

LED is used in the field of lighting. It is a hot topic in the lighting industry in China and the world. Through the continuous efforts of practitioners, the current system efficiency (including the driver circuit) of white LEDs for lighting under normal lighting conditions has reached 40lm/w. In addition, the manufacturing cost of LEDs for lighting has dropped significantly, so white LEDs for lighting have been put into commercial conditions for some lighting applications.

However, due to the situation caused by the industrial structure distribution of China for many years since the planned economy era, the current industrial groups that manufacture LEDs often lack understanding of the basic knowledge and requirements of lighting appliances, and the traditional lighting production groups are often lacking. In-depth understanding of the LED characteristics of lighting, in the design and application of the characteristics of the LED is not fully utilized, to promote the use of long and short, so that when the lighting LED is applied to the lighting device, there are many unreasonable misdesigns.

This paper presents the following insights on some of the major issues in the application of LEDs for lighting applications in road lighting.

one. Features of lighting LEDs used in road lighting

1. Current status and defects of ordinary road lighting

At present, the light source commonly used in road lamps is a high-pressure sodium lamp or a metal toothed lamp. The most characteristic of these two kinds of light sources is that the size of the arc tube that emits light is small, and a large light output is generated by a small-sized arc tube, and has a very high High light efficiency, the former includes supporting electrical appliances, up to 110 lm / w, the latter including supporting electrical appliances up to 80 lm / w. However, when such a light source is applied to a road lamp, only about 40% of the light directly passes through the glass cover to reach the road surface, and other light is projected through the lamp reflector to project the lamp. Conventional lamps that generally use such a light source are currently widely used. There are basically two deficiencies.

First, the illuminance in the direction of direct illumination of the luminaire is very high, and it can reach more than 50 lx on the secondary road. This area is obviously over-illuminated, and the illumination at the intersection of the two lamps is only 40% of the illuminance under the lamp~ 20%.

Second, the efficiency of reflectors of such lamps is generally only 50% to 60%, so about 60% of the light output is in the lamps, and is projected onto the road after losing 40% to 30%. The overall efficiency of such lamps is generally around 70% (the efficiency of such road lamps of internationally renowned brands can reach 80%), and the excessive illumination in the above-mentioned over-illuminated area is also wasteful.