What Is LED Street Light Head?

1. Brief introduction

Street light is an important part of urban lighting.

The traditional street light head often uses high-pressure sodium lamp, the overall low luminous efficiency of high-pressure sodium lamp shortcomings caused a huge waste of energy, therefore, the development of new high-efficiency, energy-saving, long life, high color rendering index, environmental protection of the street light head of urban lighting energy saving is of great importance.

At present, LED lighting technology is becoming increasingly mature, high-power LED light source efficacy has reached 100LM / W or more, which makes the city street lighting energy-saving transformation possible.

LED street light head, especially high-power LED street light head, is a rapid pace of impact on the traditional street light head market.

The standard of LED street light head is generally 0.48 average illumination of road illumination uniformity.

Light spot ratio 1:2, in line with the road illumination.

The actual 1/2 center light spot to 25LUX, 1/4 center light intensity to 15LUX, 16 meters away from the minimum light intensity of 4LUX, overlap light intensity of about 6LUX.

The current market street light head lens material is improved optical material, transmittance over 93%, temperature resistance -38-+90 degrees, anti-UV ultraviolet `yellowing rate 30,000 hours without change and other characteristics. It has very good application prospects in the new city lighting.

2. Unique heat dissipation design

The traditional LED street light head design mainly focuses on the lumen number of LEDs, while less attention is paid to the heat dissipation of LED lamps.

In fact, the number of LED lumens is rapidly increasing.

In 2009, the number of lumens per watt of mass-produced LEDs has reached 100 lumens, and this value is still growing rapidly.

The corresponding theoretical system of heat transfer has matured, and the means of heat transfer we can use are basically clear: conduction, convection, radiation, and phase change heat transfer.

Therefore, in the heat transfer or heat dissipation problem, we can take measures that are visible and limited.

LED street lamp head heat dissipation technology, the general use of mostly heat-conducting plate way, is a 5mm thick copper plate, in fact, is considered an even-temperature plate, the heat source even temperature off.

There are also installed heat sinks to dissipate heat, but the weight is too large.

Weight is very important in the street light head system, the general street light head height of six meters to one, if too heavy danger increases, especially in the event of typhoons, earthquakes may produce accidents.

LED Master adopts the world’s first needle heat dissipation technology, needle heat sink heat dissipation efficiency than the traditional sheet heat sink has been greatly improved, can make the LED junction temperature than ordinary heat sink lower than 15 ℃, and waterproof performance than ordinary aluminum heat sink is better, while the weight and volume has also been improved.

LED street lamp head heat dissipation methods are: natural convection heat dissipation, the addition of a fan to force heat dissipation, heat pipe and circuit heat pipe heat dissipation.

Adding a fan to force heat dissipation method system complexity, low reliability, heat pipe and circuit heat pipe heat dissipation method high cost.

The street light head has the advantages of outdoor night use, heat dissipation surface is located on the side above and the size of the smaller restrictions conducive to natural air convection heat dissipation, so the LED street light head is recommended to choose the natural convection heat dissipation method as far as possible.

LED street lamp head heat dissipation design problems are: heat dissipation fin area arbitrarily set, heat dissipation fin arrangement is not reasonable, the layout of the lamps and lanterns heat dissipation fins do not take into account the way the lamps and lanterns are used, affecting the effect of fins, emphasizing the heat conduction link, ignoring convection heat dissipation link.

Although many manufacturers consider a variety of measures: heat pipe, loop heat pipe, add thermal grease, etc., but did not recognize that the heat ultimately depends on the exterior area of the lamp to dissipate, . Ignore the balance of heat transfer.

If the temperature distribution of the fins is seriously uneven, it will lead to a part of the fins do not work or the role is very limited.

3. Advantages and disadvantages

3.1. Advantages

(1) Characteristics

The unidirectional nature of light, no light diffusion, to ensure light efficiency.

(2) Secondary optical design

The light from the LED street lamp head is irradiated to the area to be illuminated, which further improves the light efficiency to achieve energy saving.

(3) Light source efficiency

Currently has reached 90-110LM / W, and there is still a lot of room for development, theoretical value of 250lm / W.

And high-pressure sodium lamp luminous efficiency is increased only with the power, so the overall luminous efficiency LED street lamp head than high-pressure sodium lamp.

This overall luminous efficiency is theoretical, in fact, more than 250W high pressure sodium lamp luminous efficiency than LED.

(4) Color rendering

LED street light head light color rendering than high-pressure sodium lamp is much higher, high-pressure sodium lamp color rendering index is only about 23, while the LED street light head color rendering index of 75 or more.

From a visual psychological point of view, to achieve the same brightness, LED street light head light illumination can be reduced by more than 20% on average than high-pressure sodium lamps.

(5) Light decay

LED street light head light decay is small, a year of light decay of less than 3%, the use of 10 years still meet the requirements of road illumination, while the high pressure sodium light decay is large, about a year has dropped by more than 30%.

(6) Power

LED is a low-voltage devices, drive a single LED voltage for the safety voltage, series of single LED power are 1 watt, so it is a safer power than the use of high-voltage power supply, especially for public places (for example: street lighting, factory lighting, automotive lighting, civil lighting, etc.).

(7) Long life span

Can use more than 50,000 hours, the shortcoming is that the life of the power supply is not guaranteed.

3.2. Disadvantages

(1) single LED power is low

In order to obtain high power, more than one need to be used in parallel.

(2) Light spot

Because of the white LED itself manufacturing process defects plus the reflection cup or lens with the error, easy to cause the “yellow circle” problem. 3.

(3) Heat dissipation

Street lamp head is a high-power LED light source, high-power LED heat dissipation is difficult to solve the problem, and overheating will significantly reduce the brightness, light decay is serious, so the power can not do too much.

4. Light beads

In addition to the above-mentioned characteristics, LED street light head lamp beads also have their own characteristics.

Single LED power is generally 1W, input voltage AC170-265V.

LED color temperature white yellowish, warm white, positive white.

Luminous efficiency of 90Lm / W or more.

Color rendering coefficient R>75, light distribution curve bat-shaped light distribution curve or rectangular light spot.

Protection class IP66, can withstand ambient temperature -40 ~ 50 ℃, service life of more than 50,000 hours.

Performance characteristics.

(1) LED light source using imported top chips, fully automatic packaging equipment, imported packaging technology, life expectancy of 50,000 hours (10 years) or more.

(2) the use of the most advanced secondary light distribution technology, the best optical distribution, bat-shaped light distribution curve or rectangular light spot, the light output rate of the lamp can reach more than 90%.

(3) Use AC wide voltage power supply, regulated constant current driver, power factor above 0.95, power efficiency above 92%, can be directly connected to AC voltage use.

(4) The lamp shell is made of aluminum alloy with high thermal conductivity, and the lamp shell is integrated with the heat sink design, which can be directly convected with the air for heat dissipation.

(5) lamps and lanterns tempered glass translucent cover, effective explosion-proof, dustproof, waterproof design, can be used normally in -40 ℃ ~ 50 ℃ ambient temperature.

(6) LED light source optional color temperature: white yellowish 2700K-4000K, warm white 4000K-6000K, positive white 6000K-6400K.

(7) beautiful and generous appearance, green energy-saving, environmental protection.

5. Additional information

LED street light head is mainly applied to urban expressway, highway, main road, secondary road, branch road, street, factory, school, garden, park, district, courtyard square and other road lighting.