Industry news

2016August

Influence factors and optimal solution of LED quality of decryption

From: www.szbako.com Data:27/08/2016

most lighting designers believe that the quality of all LED products is the same. However, LED manufacturers and suppliers are numerous, Asian manufacturers to the global supply of low-cost LED. Surprisingly, only a small portion of these manufacturers can produce high quality LED. Low quality LED is sufficient to meet the requirement for a simple indication of the application. But in many requirements of consistency, reliability, solid instructions or lighting, etc. must adopt the high-quality LED, especially in harsh environments, such as in highway, the military /aerospace, and industrial applications.

in New York subway station and other environments, the security requirements are very harsh, LED must meet the basic factors of high quality requirements. What are the factors that distinguish the quality of LED? How to tell the difference between the two types of LED? In fact, the selection of high-quality LED can start from the chip until the assembly is completed, there are many factors that need to be considered during this period. Tier-OneLED manufacturing company is able to produce excellent, consistent quality of the wafer is made from high quality LED manufacturing materials, and then can create a good chip. The chemical material used in the wafer fabrication process is a very important factor in determining all the performance parameters of LED.

a 2 inch wafer can be cut out more than 6000 LED chips, which only the performance of individual chips and the overall performance of different. As an excellent chip manufacturers chip differences in color, brightness and the voltage drop is very small. When the LED chip package is complete, many of their performance indicators are likely to be very different, such as the perspective. In addition, the impact of the packaging material is also considerable, for example, the performance of the epoxy resin is better than the silicone resin. LED manufacturers are not only able to make high-quality chips, but also has a LED based on the color, brightness, voltage drop and different perspectives on the ability to carry out classification of packaging. High quality LED suppliers will provide uniform operating characteristics of products to the customer, and lower quality LED suppliers can only provide similar to the "mixed" led. For high-end, strict quality requirements of applications, such as airport runway boundary lamp must meet the FAA's color and brightness specification, in order to ensure the performance and safety, the consistency of LED packaging is strictly limited. Poor packaging grade LED is used in demanding applications will lead to premature failure and a series of inconsistent problems, it is likely to lead to major accidents. In order to avoid downtime and ensure the specified in the design of LED has reliable operating characteristics, in the high-end and stringent quality requirements of application to avoid the use of "mixed" products is very important. Product matching capability in addition to discrete LED, LED assembly and power supply for its performance, brightness and color, and other indicators have a very important impact. Due to the environmental temperature, working current, circuit structure, voltage spike and environmental factors can affect the performance of LED indicators, the appropriate circuit design and assembly is the key to protect the LED and ensure the performance. LED manufacturers also use a variety of techniques and different materials to design the circuit structure and assembly, in most cases, the LED assembly experience level difference will resulting in applications with a LED in overall performance and reliability are different.

with the rapid growth in demand for LED, manufacturers and assembly plants in the global market for services also increased rapidly. But it is regrettable that the surge in support for manufacturers is not only a large number of low quality LED, their packaging and LED design engineers are relatively inadequate experience. Therefore, in addition to the existing experience through accurate screening led suppliers, OEM manufacturers must also study their circuit design and assembly technology to ensure that it meets the design specification, design, and whether to provide a sufficient heat dissipation capability, because the cause of LED fault and inconsistent performance of the main factors is overheating. To ensure that it meets the design requirements OEM must detection of the LED assembly and circuit structure of third-party testing in order to eliminate the injustice that exist in the test, many companies are commissioned third-party to test the LED assembly and circuit structure. A LED device may be tested in harsh environments or used for several weeks. In the testing process, while the pressure, temperature cycle, voltage fixed /change, current fixed /change test, other harsh environmental conditions of the test to determine whether the application of LED to meet the requirements. A large number of parameters to be recorded before and after the test, and to monitor the changes in the LED brightness, color and voltage drop.
accelerated life cycle testing is a key test to avoid failure in special application areas. Testing helps to ensure that those who are expected to screen out at least 100000 hours of work, but only 1000 hours of work in advance of the failure of the LED. This situation is likely to occur, because the low quality of LED (also may be assembled in the design of unreasonable high quality LED) at 1000 hours after the brightness will be reduced. In fact, a low quality LED if there is a higher driving current in the work will be more bright than high quality LED, however, the high current will make the LED fever too fast, and the final result is brightness dimming or burning. In addition, the assembly technology to a certain extent, the impact on the performance of LED than the chip itself is also a big example of. The design engineer should ask the LED supplier for LED reliability specifications, and it should also be assembled and tested for LED to ensure that the brightness is indeed better. Some of the best supplier of LED can ensure that they led assembly technology of reliability to last three years or longer, and can provide further contains high-quality LED and for a special application of appropriate design, ultimately led products. The importance of the detection of two applications in the field of transport helps to explain the full test of how to prevent LED from occurring in the application of highly visible. In the early 1990s, LED used car and truck brake lights. Some LED design soon appeared on the performance of the indicators of inconsistency, and soon burned, and the reason may be due to the quality of the LED problem, perhaps the product itself is completely designed. Until recently, when LED became a more suitable light source in traffic signal lights, this phenomenon has been paid attention to. Designed to be covered with LED of 8 inch or 12 inch printed boards the company must consider the environment and application requirements in the selection of LED and improved design. Any of the above case, if the test pressure or accelerated life cycle testing have been done, you can think is high-quality LED or LED assembly is qualified, also can be applied in need of longer service life and higher reliability of the occasions the. Rational use is not a high quality LED assembly technology for each application. If the LED assembly does not meet the stringent environmental requirements, the application will not necessarily greater security risk, or if the maintenance cost of the final product is not very high by assembly technology for some of the difference may be more appropriate.

the most fundamental point is that LED must be able to afford the. Therefore, in the limit of the cost requirements, it is necessary to consider the supplier's product packaging level, assembly design and testing of the experience and other factors. Meet the application and market demand of the design is the most effective means of service in the end user. If the application needs high-end solutions, then the choice of chip suppliers, design experience, as well as the test should be taken into account. If you do not consider the sale price of high-end products, you should carefully consider the difference between good and bad LED other related factors. Have the classification ability led suppliers of packaging level and reliability and accelerated life cycle testing of the manufacturers is a long-term partnership, which helps manufacturers to adopt more reliable led the development of high-end products.

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