The life span of led beads depends on the basic knowledge of _led beads

Five factors affecting the life of LED lamps

If the light source is used for a long time, it will bring huge economic benefits and reduce the carbon footprint. The system design shows that the decay of light speed is a routine process, but it can be ignored. When the speed of light decays very slowly, the system can be kept in good condition without long-term maintenance.

LED is really better than other lamps in many applications. In order to keep the system in good condition, the following five factors need to be considered.

1. Efficiency

LED lighting and LED modules are manufactured and driven within specific current ranges. LED can provide 350mA to 500mA current according to its characteristics. Many systems operate in the high value region of this current range.

2. Acidic conditions

LED is also vulnerable to acidic conditions, such as coastal areas with high salt content, factories using chemicals or manufacturing products, or indoor swimming pools. LED is also tailored for these areas, but must be carefully encapsulated on a fully enclosed cover plate and require a high level of IP protection.

STEP 3 Heat

Heat will affect the speed of light and life cycle of LED. The radiator prevents the system from overheating. The heating of the system means that the acceptable ambient temperature of LED lighting has exceeded. The life of LED depends on the ambient temperature.

4. Mechanical stress

When fabricating, stacking or simply operating LED, mechanical stress will affect the life of LED lamp, and sometimes even completely destroy LED lamp. Note that electrostatic discharge (ESD) can cause short but high current pulses that can damage LED and LED drivers.

Step 5 Humidity

The performance of LED also depends on the humidity of the surrounding environment. In a humid environment, electronic equipment, metal parts, etc. tend to damage quickly and start rusting, so try to keep LED systems away from humidity.

How do we know about LED beads?

LED bead LED is called semiconductor light emitting diode, which is a light emitting device that directly converts electric energy into light energy and electric signal into optical signal, and is made of semiconductor material; It is characterized by low power consumption, high brightness, bright colors, large vibration, long service life (normal luminous 8-100,000 hours), cold light source and other advantages, which is a real "green lighting". Lighting products with LED as light source will inevitably replace white straight lamps and become another revolution of human lighting in the future of the 21st century.

The development of led bead illumination is due to the advantages of led bead such as adaptability, life span and efficiency, which are superior to the previous illumination forms. Therefore, it is easy to understand why LED lighting is widely used in household lighting, industrial lighting for factories, marine environmental lighting, architectural lighting, design and many other applications. With the rapid development of led lamp beads and solid-state lighting industry, led lamp bead developers apply technology to harsh environments. Today, we discuss the necessity of protecting led beads and circuit components in harsh environments such as marine applications. Coatings and other protective technologies can extend the life and performance of solid-state lighting systems.

With the rapid development of led lamp bead market, the correct choice is the key to ensure the performance and life of led lamp bead. Today, we highlight the use of led lamp beads in different environments and introduce how to properly protect them in these environments. The development process should ensure good optical performance of solid-state lighting system while ensuring reliability. The applications of led lamp beads are becoming more and more diversified. Whether it is design requirements, location, or product functionality, it proves that the challenges faced by led bead designers are constantly changing. Like most electronic devices, led beads perform well until their performance begins to decline due to external influences. These effects include dust, electrostatic attraction in wet or corrosive environments, chemical or gaseous contamination, and many other possibilities. Therefore, the end-use environment should be fully considered and suitable products should be selected.

Comparing the environmental conditions in the application of standard building lighting with the marine environment can help understand the potential causes of deterioration. In architectural lighting applications the lighting unit may be designed to cover the led bead itself or only be exposed to general changes in ambient temperature and humidity for the direction of the led bead. In marine environment, led lamp beads will splash into salt water or be soaked. In addition, on all occasions, the service life of led lamp beads is mostly worked in salt spray environment. High salinity conditions will lead to PCB corrosion, and its performance changes faster than conventional humidity. Usually in this environment, sealing resin and prosthesis coating can provide a high level of protection.

Sealing resin

Sealing resins are of many chemical types, including epoxy resin, polyurethane resin and silicone resin. In general, epoxy resins provide stronger protection against mechanical effects, while other chemicals are not soft, which may lead to problems in thermal cycling. In addition, standard epoxy resin cannot provide clarity and color stability of other systems.

Silicone resin is very transparent and performs well at extreme temperatures. Carbamate resin can also provide good flexibility, transparency and high level of protection in harsh environments. After irradiating three types of resins with UV light for 1000 hours, the color difference and transparency difference of three types of resins were studied, and experiments were carried out to characterize the stability of each resin under outdoor conditions. Silicone and carbamate resins are much superior to standard epoxy resins.

Talk of experience

You can also compare the performance of various products in harsh environments and select products according to the final use conditions of users. For example, the influence of corrosive gas environment on acrylate protective coating, polyurethane resin and silicone resin. By emitting three gases into a mixed environment, the reduction of beam ratio in led lamp beads is confirmed. This result fully illustrates the importance of choosing products suitable for the environment. The surface insulation resistance of the conformal coating will not deteriorate in corrosive gas environment, but for led lamps, if the led lamps are broken through by a thin layer of coating, the performance will decline with time, which can not fully protect led lamps.

Silicone has the same effect. But in the experiment, the gas can influence the led bulb through the resin, even though the protective layer is quite thick (2mm vs 50 microns). The comparison between silicone and polyurethane materials shows that silicone is transparent to the matrix, while polyurethane resin with the same thickness is not, so the properties of these two chemical types are different. In this case optically transparent polyurethane resin is the best material for protecting led lamp beads from corrosive gases.

Polyurethane resin is considered to be suitable for protecting led lamp beads in various environments. These can be modified to provide additional benefits such as a shading system that covers the PCB but does not exceed the height of the led bulb. This resin is used for PCB protection, which not only makes the surface comfortable, but also increases the light output through PCB reflection and improves the lamp performance. There is also a special resin for diffusing the light of led beads.

Matching protective materials

Experimental comparisons show that sealing resins can provide a high level of protection in different environments by selecting chemical types or by specific resin formulations. However, as mentioned above, it is discussed that the conformal coating in the film has little effect on the color temperature. Comparing the thickness of conformal coating with that of sealing resin, it is clear that the improvement of resin protection grade can produce more coatings. Susie one? It can be increased to a depth of more than 2mm, but this depth will also affect the observed color temperature level.

The general color temperature movement of polyurethane led lamp beads with different thicknesses. Obviously, thickness is directly related to the degree of color temperature offset, so it is also an important consideration when choosing appropriate protective materials. It is known that color temperature offset will occur, but led lamp beads need to consider the repeatability of offset. If the offset persists, the color temperature of the original led lamp bead can also be re-examined.

Protection options

Protective coatings are usually thin coatings suitable for PCB contours, providing good protection without significantly increasing the weight or volume of the circuit board. Is the general thickness 25? 75 microns, easy to use by spraying or dipping technology.

In order to protect the top of led beads, the coating used must have good transparency and remain clear in the desired environment throughout the service life of the product. When used outdoors, the coating may need good UV stability. Therefore, the best type of protective coating acrylic acid based on chemicals provides clarity and color stability, and provides good protection from humidity and salt fog. Acrylic coating provides good protection in salt atomization test.

Generally speaking, acrylic conformal coatings are solvent-based products, and the solvent used is a liquid carrier that accumulates resin films on the substrate. The solvent used is volatile organic compounds (VOC). These solvents are present for only a few minutes at the application stage with led beads and are therefore not a long-term problem in many systems. In some cases, led lamp manufacturers have specific requirements for the use of VOC-containing products and other specific chemicals, which are set out in the led lamp manual. Typically chemical fitness testing helps to determine whether a solvent-based protective coating is suitable for a particular led lamp bead.

Color temperature problem

Besides the influence of coating on led lamp beads, it is also necessary to understand the influence of coating on color temperature. The correlated color temperature band common in led bead illumination changes with time, which is also called color preservation. It is found that any material directly placed on led lamp bead crystal will interact with each other, resulting in color temperature deviation.

The change of color temperature band is usually from warm temperature to cold temperature, and varies between different led lamp types and color temperature bands. In addition, it will vary according to the protective materials used. This is another area where acrylate protective coatings are superior to other chemical materials and product types.

Typical color temperature offset of warm white led lamp beads. Includes thickness and hardening mechanisms to significantly change the color temperature to emphasize the change of color temperature.

Thin and thick coatings represent the minimum and maximum thickness classes of prosthesis coatings of 25 and 75 microns. The application of this film can minimize the color temperature shift and control it within the boundary given by the manufacturer of led lamp beads.

Ideally, conformal coatings can be used for all led lamp beads due to their ease of application, small influence on illumination unit volume and weight, versatility and influence on color temperature offset. However, as we all know, one solution is usually not suitable for all applications. As mentioned above, conformal coatings provide a good level of protection in wet and salt atomization environments, but protective coatings do not provide the highest level of protection in frequent flooding, chemical spraying and corrosive gases.

If the conditions are more difficult, it is recommended to replace it with sealing resin. In this case, the choice between chemical types depends on the end-use conditions and specific environmental impacts. Also consider the thickness of resin to be added, minimize the influence on color temperature change, and ensure adequate protection.