Most lighting designers believe that the quality of all LED products are the same. However, many LED manufacturers and suppliers, Asian manufacturers to global supply low-cost LED. Surprisingly, only a small part of these manufacturers to create high-quality LED. For applications that only used as a simple indicating the role of the low quality of the LED is sufficient to meet the requirements. However, in many areas of the requirements of consistency, reliability, solid-state instructions or lighting must be high quality LED lights, especially in harsh environments, such as highways, military / aerospace, and industrial applications.
Safety requirements is very harsh, LED must meet high quality requirements of the fundamental factors in the environment of the New York subway station.
What are the factors that distinguish between the LED level of quality? How to tell the difference between the two LED’s? In fact, the selection of high quality LED from the chip until assembly is complete, during which there are many factors to consider. Tier-OneLED manufacturing company to produce excellent and consistent indicators wafer start from the high-quality LED manufacturing materials, enough to make a good chip. Determine the conditions of the LED performance, the chemical materials used in wafer production process is a very important factor.
A 2-inch wafer can be cut out more than 6000 LED chip, there is only individual chip performance and overall. A good chip manufacturer makes chips in the difference of color, brightness, and the voltage drop is very small. When the LED chip package is completed, many of their performance, there may exist a great difference, such as perspective. In addition, the impact of packaging materials is quite large, for example, silicone epoxy performance.
Classification ability
Excellent LED manufacturers can not only produce high quality chips, but also has the ability, depending on the LED color, brightness, voltage drop and perspective of its classification packaging. High-quality LED suppliers to provide customers products with consistent operating characteristics, while lower-quality LED suppliers only provide LED similar to the “mixed”.
For high-end, quality-demanding applications, such as the boundaries of the airport runway lights must meet the FAA-class color and brightness specifications, to ensure consistency of performance and security, LED packaging is strictly limited. Packing poor LED is used in demanding applications will lead to premature failure and other non-consistency problem is likely to lead to major accidents. Avoid the use of “mixed” products in the high-end and quality demanding applications in order to avoid equipment downtime, and ensure that the provisions in the design of the LED with reliable operating characteristics, it is very important.
Products supporting capacity
In addition to the separation of the assembly and supply of LED, LED indicators for its performance, brightness and color have a very significant impact. Due to ambient temperature, operating current, the circuit structure, voltage spikes and environmental factors and so can affect the LED performance indicators, the appropriate circuit design and assembly is critical to protect the LED and to ensure performance. LED tube manufacturers use a variety of techniques and different materials to design the circuit structure and assembly, in most cases, the LED assembly on the experience level of the difference will cause the LED in the same application there are differences in overall performance and reliability.
With the rapid growth of the LED needs, serve the global market manufacturers and assembly plants also increasing rapidly. It is regrettable that the surge in support for manufacturers not only a large number of low-quality LED packaging and LED design engineers to experience a relative shortage of Therefore, in addition to the existing experience and accurate screening LED suppliers, OEM manufacturers must also examine their circuit design and assembly technology to ensure that it meets the design specifications, and design to provide sufficient cooling capacity, because the cause of LED failure and performance The inconsistency of the main factors is overheating.
To ensure that it meets design requirements, the OEM must detect the LED assembly and the circuit structure
Third-party testing
In order to eliminate the injustice that exist in the test, many companies have commissioned a third-party to test the LED assembly and circuit structure. LED devices may be tested in the harsh environment, or use a few weeks. During the test, at the same time the pressure, temperature cycling, fixed voltage / change current fixed / change test, test to determine whether the LED to meet the application requirements in other harsh environmental conditions. Test before and after a large number of parameter changes must be recorded at the same time to monitor the changes in the measured LED brightness, color, and voltage drop.
Accelerated life cycle testing is a key test to avoid failure in special applications. The test helps to ensure that screen out those expectations at least for 100,000 hours, but only work 1000 hours in advance of failure LED. This situation may arise because of the low-quality LED (high quality LED assembly designed to be unreasonable) will reduce the brightness after 1000 hours of work. In fact, if a lower-quality LEDs have a higher drive current at an early stage is high-quality LED is brighter, however, the excessive current causes the LED heat too fast, the final results are dimmed or burned.
In addition, the assembly technology to some extent on the LED performance than the chip itself is also a big example. The design engineer should ask for the reliability of the specifications of LED to LED suppliers, and the LED assembly and testing to ensure that the relatively high brightness is indeed better. Some excellent LED suppliers can guarantee the reliability of their LED assembly can be sustained for three years or longer, and can further provide the ultimate LED products, including the appropriate design with high quality LED and for special applications.
The importance of the detection
Two applications within the field of transport helps to explain adequately tested, how to prevent the LED fails to provide a high degree of visibility applications. In the early 1990s, LED brake lights for cars and trucks. Some LED designs quickly inconsistencies in the performance indicators, and soon burned down, the reason is perhaps due to the quality of the LED, perhaps completely the design of the product itself. Until recently, the traffic lights be more appropriate, when the LED light, this phenomenon was attention. The design covered with LED diameter of 8 inches or 12 inches of PCB companies must consider in the choice of the LED and to improve the design environment and application requirements.
Any of the above situation, if the stress tests or accelerated life cycle testing has been done can be considered high-quality LED or LED assembly is qualified, it can be applied to require a longer service life and higher reliability the occasion.
Rational use of
Not every application needs high-quality LED assembly technology. If the LED assembly does not meet the requirements of harsh environments, the application will not necessarily greater security risk, or, if the maintenance costs of the final product is not very high, the use of poor assembly techniques may be more appropriate.
The most fundamental point is that the LED must be able to afford. Therefore, the cost requirements within the constraints, we must consider the supplier of the product packaging grade, assembly design experience and testing. Designed to meet application and market demand is the most effective means to serve the end user. If the application requires high-end solution, then the chip vendor’s choice of design experience, and testing are all factors to be considered. If you do not consider the sales prices of high-end products, it should be carefully considered other relevant factors of the difference between good and bad LED. Have to classify the ability of packaging grade LED suppliers, as well as to reliability, accelerated life cycle testing, manufacturers can be long-term cooperation, which helps manufacturers to adopt more reliable LED development of high-end products.