High-power white LED has already entered the application of the lighting. We need to pay attention to the product reliability, because some quick and dirty LED only have the requirement for the instantaneous brightness ( Brightness Meter ), it lacks a reasonable heat design and optical design, and can’t fully guarantee the advantage of LED light source, so as that LED industry can’t begin rapid development. The reliability of the lamps belongs to the system reliability category, the research mainly includes the following several aspects:
(1) Due to the unreasonable structural design and bad heat dissipation, lumens depreciation is caused, even LED light is failed.
(2) Due to the unreasonable installation, the resistance of the contact points with lamps and LED is too great, it will make the temperature of LED chips is high enough to cause lumens depreciation even light failure.
(3) High drive current will cause high temperature of LED and lumens depreciation even light failure, or lamps power failure caused by the drive failure.
(4) According to the needs of Light road design, choosing LED of different light angle to meet the requirements of the optical structure lamps may cause bad cooling and lumens depreciation even light failure.
(1) Different types of LED device has different failure mechanism, the reliability study of white LED device can conduct the contrast test on the same batches of the blue-ray chip and white light chips. Through the contrast experiment, we can analyze the reason of the failure of white LED, namely the failure of the blue chip plays the leading role, or the failure of the external phosphor plays a main role.
(2) For the accelerated LED life tests of the devices, we should consider the consistency of the performance of the devices, we not only need to select the same the batch products of the same manufacturer, and we also need to consider some initial parameters (such as the open voltage) for classification. Because even though the same batches of the device, the performance will have a very big difference, and the reliability study of LED should start from the subtle.
(3) We should pay more attention to the value of the reliability of LED application products, and take the advantages of LED device to promote the development of the industry. At present, high power white LED application is not very mature in illumination, the application products haven’t really been put into market, we need to enhance the quality and improve the research of the reliability.