In some cases, packaging process impact more influence on LED lights chips than themselves. Before designing lamps, engineers should request LED standards or specifications from their suppliers, and conduct light intensity test to ensure that package did not distort the original parameters too much. Good LED chip suppliers can guarantee that the reliability of their LED package will maintain at least three years. Some of them even provide customized high quality LED chips according to the specific requirements.

Testing before production is rather important. There are an example in transportation area can help explaining how tests can prevent LEDs failure in high-degree visibility applications. In 1990s, LED products were used as stoplights on cars and trucks. The performance differences due to the inconsistence of LED chips caused serious damages for these lights and even traffic accidents. Not until recently, when LED lighting technique started to use as traffic lights, this issue received enough attention. Pressure test and accelerated life cycle test are two new modules that typically designed to solve this problem. Those high quality LED chips which has passed these two tests can really safe to used in more harsh conditions.

 

Not every application required high quality LED chips with advanced and precise packaging. If packaging cannot meet the stringent demands, serious accidents are still avoidable. If the cost of maintenance is reasonable and a few defects are also acceptable, producers will intend to use worse LED packaging.

 

The most essential point is whether these high quality LED chips can be affordable. If producers never consider of the cost, they can obtain a perfect LED chip with highest quality and best packaging but also a ridiculously high cost. Therefore, within the constraint of cost, packaging level, assembling design and testing should be taken into account. There must be some trade-off. If price were not a consideration, LED lighting manufacturers need to spend a lot time on choosing the best LED chips and co-operate with those LED street light suppliers whose can provide a complete set of reliability and accelerated life cycle tests. In most cases, this kind of co-operation will be long termed. The large potential profit let many medium and small businesses scramble for.

Except individual LED chips, LED Lights packaging and LED power supply can impact significant influence on their capacities, brightness and color. We defined them as internal factors. External factors are mainly from circuits and other electronic components. Since working temperatures, current, circuit construction, voltage peak can also affect the performance of LED chips. Proper circuit design and assembly is the key to protect the LEDs and ensure their performance. During the packaging process, even different assemblers with different working experience will cause the non-uniformity.

 

With the rapid development of LED demand, the global-oriented LED chip suppliers and packaging factories are booming simultaneously. Unfortunately, the over-booming trend made many manufacturers choose to use low quality LED chips to reduce cost. Besides, their LED packaging designers and engineers are usually lacking of working experience. Most OEM producers have no capability to establish their own LED chips sections. Replying on other LED chip suppliers is their single solution. Experienced producers know how to choose right suppliers and also conduct a series of testing for LED packaging and circuit structure.

 

In order to eliminate the injustice during the testing, many companies chose to employ a third party to test the quality of LED street light chips. In the period of testing, randomly chosen LED chips will be gathered together into some specific testing rooms. These LED chips will be continuously working for several weeks in the harsh conditions, including pressure test, temperature test, fixed/flexible voltage test, fixed/flexible current test, etc. A large amount of data should be recorded before and after the testing. The three major parameters of LED: light intensity, color, potential drop should keep in record during the entire testing process. Only high quality LED chips can survive from it.

 

Accelerated life cycle testing is a key point to avoid failure in special applications. This test can help eliminating those LED chips which has an estimated service life more than 100000 hours but will be failed after 1000 hours work. This happens often. The light intensity of low quality LED chips (or high quality LED chips with unreasonable assembling) will drop dramatically after 1000 hours work. In fact, low quality LED tubes chips using higher driving current are more brightness than high quality LED chips in the early stage of service. However, continuously working in high temperature may cause huge damages to them.

Most LED lighting designers believe that all LED chips have same quality. However, there are hundreds of thousands of LED chip providers or LED chip manufacturers. Asian LED Lights manufacturers can produce the cheapest LED chips all around the world. But, to buyers’ astonishment, only very few of them can actually make high quality LED chips. Low level LED chips can only be competent in small lamp market. But in other application area, in which LED products should be used under severe environment (expressway, military/aviation, other industry), high quality LED chips are necessary.

 

For new comers in LED industry, how to judge the quality of LED products became one of the must-to-be-learned subjects. In fact, choosing high quality LED chips is the first step. Currently, the internationally recognized best LED chip manufacturer is CREE. Chips made by CREE have a common property of high lighting efficiency. Compare with other LED chips with the same power consumption, like Epistar, SAMSUMG, CREE chips will have more than 5%-10% luminous flux. And also, CREE chips have less light attenuation, which means, the actual service life of their chips is longer than the estimated 50000 hours.

 

If taking chip materials and manufacturing process into account, the most advanced wafer fabrication process must be the essential point. A 2-inch wafer can be cut into more than 6000 LED chips. Using one wafer, a good manufacturer can limited the differences of chips within a very slight region in almost every aspect (chip color, brightness, voltage drop). The differences can only be generated during the packaging process. Low quality LED chips will have huge differences in properties during the chip-cutting process, not to mention the packaging process. Thus LED chips generated by small factories are kind of mixtures without any classifications.

 

Best LED chip manufacturers not only produce high quality LED chips, but also perform classified packaging according to basic LED chip parameters: color, brightness, potential drop, and optic angle. A good LED street light chip suppliers will provide their customers with unified products (with much similar basic parameters).

 

In application area which high quality chips were required, like boundary lights on the airport runway, must reach FAA level certificate. In order to avoid significant accidents, mix-packaged products with much worse uniformity cannot be used.