LED wall washer for landscape lighting

LED lighting can be divided into three parts according to the application: indoor lighting, road lighting and landscape lighting. In terms of scale, the indoor lighting market will grow into the largest market due to the wide range of application groups. LED landscape lighting lamps have a huge market, especially the LED wall washer that has outstanding performance in lighting projects.

In the early stage of development, the landscape lighting semiconductor lighting market was dominated by low-power LED strings and decorative lights, plus traditional neon tubes. With the promotion and popularization of high-power LED floodlights, wall washer lights, and contour lights, their application range is becoming more and more extensive. 

The structural design of the wall washer needs to fully consider the heat dissipation and waterproof of the LED, which is based on the design for manufacturability (DFM).

The outer surface temperature of the lamp is basically lower than 70 ℃, the PN junction temperature of the LED chip is higher than 100 ℃, and the thermal resistance is within 10 ℃/W. The 6063 aluminum profile can also ensure good heat dissipation, so the heat dissipation problem can basically be solved. 

The waterproof problem in structural design has become a key point. At present, most manufacturers still use the method of glue filling, and the lamp body is not easily damaged even if it is immersed in water for a short period of time. But long-term acid rain corrodes the colloid can cause the lamp to die, so the end cover and glass of the lamp must be sealed, and the cross-sectional area of the lamp shell (generally the wall thickness is greater than 1.2mm) should be increased in the design to better contact the end cover. Sealing glass requires skill. The glass glue is evenly distributed, and the covered glass cannot be bent or deformed to ensure that it does not leak. There are 3 ways to glue glass, namely manual, pneumatic (or semi-automatic) and fully automatic machine glue. At present, the most economical method is to use pneumatic manual gluing. 

The light from the wall washer should wash the wall evenly like water surface, thus highlighting the shape and outline of the building. But it is difficult to achieve the desired effect. Low power, long distance, and high uniformity are the biggest difficulties faced by lamp manufacturers. According to the current situation of actual project installation, the projection distance of the wall washer must be greater than 1 m. The high-power wall washer lamps are theoretically consistent, but the power must exceed 24 W, and the installation distance between the LED and the wall must be More than 3 cm.

Drive is very important in any LED lamp, directly related to the service life of the lamp. The LED high-power wall washer is generally powered by low-voltage DC24V. After determining the low-voltage constant current driver chip and scheme, the selection of peripheral circuit components must also be cautious.

The resistance of the electrolytic capacitor should exceed 105℃, because most of the driving circuit adopts the integrated LED design, the heat emitted will be transferred to the electrolytic capacitor, long-term use or cause the electrolyte to dry out, resulting in circuit failure.