Most designers assume that all LED products are of the same quality (just most, not including you). However, there are many manufacturers and suppliers of LEDs, with Asian producers, especially those in China, supplying low-cost LEDs globally. Surprisingly, only a small percentage of these manufacturers are able to produce high-quality LEDs. For applications that are used for simple indication purposes, low-quality LEDs will suffice. However, high-quality LEDs must be used in many areas that require consistency, reliability, solid-state indication or lighting, especially in harsh environments, such as: highways, military/aviation, and industrial applications. This requires our LED manufacturers to be good enough to produce high-quality products. So, what should a good LED manufacturer do? What are the factors that distinguish the quality of LED? We will elaborate from the following aspects: Emphasis on fundamental factors: starting with chip packaging In fact, choosing a high-quality LED can start from the chip to the completion of assembly, and there are many factors to consider during this period. Excellent manufacturing companies can produce excellent wafers with consistent indicators starting from high-quality LED manufacturing materials, which in turn can produce excellent chips. Among the conditions that determine all performance indicators of LEDs, the chemical materials used in the wafer production process are quite important factors. A 2-inch wafer can cut more than 6,000 LED chips, and only individual chips have different performance indicators from the whole. A good chip maker makes chips with very little variation in color, brightness, and voltage drop. After LED chips are packaged, there may be great differences in many of their performance indicators, such as viewing angle. In addition, the impact of the encapsulation material is also considerable, for example, silicone resins perform better than epoxy resins. Classification ability: classify and package LEDs Good LED manufacturers not only make high-quality chips, but also have the ability to sort and package LEDs according to their color, brightness, voltage drop and viewing angle. High-quality LED suppliers will provide customers with products with consistent operating characteristics, while lower-quality LED suppliers can only provide similar “mixed” LEDs. For high-end applications with strict quality requirements, such as border lights on airport runways, FAA-level color and brightness specifications must be met. To ensure performance and safety, the consistency of LED packaging is also strictly limited. Poorly packaged LEDs used in demanding applications can lead to premature failure and a host of inconsistencies that could lead to catastrophic accidents. In order to avoid equipment downtime and to guarantee reliable operating characteristics of the LEDs specified in the design, it is important to avoid the use of “mixed” products in high-end and quality-critical applications. Product Supporting Capability In addition to classifying LEDs, the assembly and power supply of LEDs have a very important impact on its performance, brightness and color. Since ambient temperature, operating current, circuit structure, voltage spikes, and environmental factors can all affect LED performance indicators, proper circuit design and assembly are key to protecting LEDs and ensuring performance. Excellent LED manufacturers also use multiple technologies and different materials to design circuit structures and assemblies. In most cases, differences in the experience of LED assemblers will cause differences in the overall performance and reliability of LEDs in the same application. difference. As demand for LEDs grows rapidly, so does the number of manufacturers and assemblers serving global markets. But unfortunately, the proliferating supporting manufacturers not only adopt a large number of low-quality LEDs, but also their packaging and LED design engineers are relatively inexperienced. Therefore, in addition to accurately screening LED suppliers through existing experience, OEMs must also examine their circuit design and assembly techniques to ensure that design specifications are met, and whether the design provides sufficient heat dissipation, because LED failure and performance The main cause of inconsistency is overheating. To ensure design requirements are met, OEMs must inspect the LED assembly and circuit construction. Commission third-party testing In order to eliminate the unfairness of the test, many companies have commissioned a third party to test the LED assembly and circuit structure. An LED device may be tested or used in harsh environments for weeks. During the test process, tests such as pressure, temperature cycle, voltage fixed/variable, current constant/variable, etc., and other tests under harsh environmental conditions are carried out to determine whether the LED meets the application requirements. A large number of parameter changes before and after the test are recorded, and changes in brightness, color and voltage drop of the LED under test are monitored. Accelerated lifecycle testing is a key test for avoiding failures in specific application domains. Testing helps ensure that LEDs that are expected to last at least 100,000 hours, but fail prematurely after only 1,000 hours, are selected. This is possible because low-quality LEDs (or high-quality LEDs with poorly designed assemblies) will lose brightness after 1000 hours of operation. In fact, a low-quality LED with a higher drive current will be brighter than a high-quality LED at the beginning of operation, however, too high a current will make the led screen wall price heat up too quickly, and the end result is dimming or burning out. In addition, there are also examples where assembly technology has a greater impact on LED performance than the chip itself. Design engineers should ask the LED supplier for the reliability specification of the LED, and should also perform assembly tests on the LED to ensure that brighter ones are indeed better. Some good LED suppliers can guarantee the reliability of their LED assembly technology for three years or more, and can go further to provide a final LED product that includes high-quality LEDs and proper design for specific applications. On the Importance of Testing Two applications in the transportation sector help explain how adequate testing can prevent LEDs from failing in applications that provide high visibility. In the early 1990s, LEDs were used in brake lights for cars and trucks. Some LED designs show inconsistencies in performance quickly and burn out quickly, either because of the quality of the LED or
