Led flood light importer to know some common knowledge about flood light

Outdoor lighting fixtures need to withstand the test of ice and snow, wind and lightning, and the cost is high. Because it is difficult to be repaired on the outer wall, it must meet the requirements of long-term stable work. The LED is a delicate semiconductor component. If it is wet, the chip will absorb moisture and damage the LED, PCB and other components. Therefore, the LED is suitable for drying and low temperature. To ensure long-term stable operation of LEDs under harsh outdoor conditions, the waterproof structure design of lamps is extremely critical.

At present, the waterproof technology of lamps is mainly divided into two directions: structural waterproofing and material waterproofing. The so-called structural waterproofing is that after the combination of various structural components of the product, it has been waterproof. The material is waterproof, so that when the product is designed, the position of the potting glue to seal the electrical components is left, and the glue material is used for waterproofing during assembly. The two waterproof designs are available for different product routes, each with its own advantages.

Factors affecting the waterproof performance of lamps
Ultraviolet light

Ultraviolet rays have a destructive effect on the wire insulation, the outer protective coating, the plastic parts, the potting glue, the sealing ring rubber strip and the adhesive exposed to the outside of the lamp.
After the wire insulation layer is aged and cracked, water vapor will penetrate into the interior of the lamp through the gap of the wire core. After the coating of the lamp housing is aged, the coating on the edge of the casing is cracked or peeled off, and a gap may occur. After the plastic case ages, it will deform and crack. The aging of the electronic potting gel causes cracking. The sealing rubber strip is aging and deformed, and a gap will occur. The adhesive between the structural members is aged, and a gap is also formed after the adhesion is lowered. These are all damage to the waterproof ability of the luminaire by ultraviolet light.

2.high and low temperature

The outdoor temperature varies greatly every day. In summer, the surface temperature of the lamps can rise to 50-60 °C, and the temperature drops to 10-20 qC in the evening. The temperature in winter and snow can drop to below zero, and the temperature difference changes more throughout the year. Outdoor lighting in the high temperature environment in summer, the material accelerates aging deformation. When the temperature drops below zero, the plastic parts become brittle, under the pressure of ice and snow or cracking.

3. thermal expansion and contraction
Thermal expansion and contraction of the lamp housing: The temperature changes cause the thermal expansion and contraction of the lamp. Different materials (such as glass and aluminum profiles) have different linear expansion coefficients, and the two materials will be displaced at the joint. The process of thermal expansion and contraction is repeated continuously, and the relative displacement is repeated continuously, which greatly damages the airtightness of the lamp.
Internal air thermal expansion and contraction: The condensation of water droplets on the buried lamp glass can often be observed on the square floor, and how does the water droplets penetrate into the lamp filled with potting glue? This is the result of respiration during thermal expansion and contraction.
For example, when the temperature is lowered from 60 ° C to 10 ° C, the internal pressure change of the lamp is about: 1 (273 + 60) K / (273 + 10) K = 0.18 atm = 1.86 m water column.
When the temperature rises, under the action of huge negative pressure, the humid air penetrates into the inside of the lamp body through a small gap in the material of the lamp body, and then encounters the casing of the lamp with a lower temperature, condenses into water droplets and gathers. After the temperature is lowered, the air is discharged from the lamp body under the action of the positive pressure, but the water droplets remain attached to the lamp. The breathing process of temperature changes is repeated every day, and there is more and more water inside the lamp.
The physical changes of thermal expansion and contraction make the waterproof and airtight design of outdoor LED lamps become complex system engineering. The following is an analysis of the technical characteristics of the two types of lighting waterproofing systems in order to understand their advantages and disadvantages.