Highly Accelerated Temperature and Humidity Stress Testing (HAST) is a highly accelerated, temperature and humidity based reliability test method for electronic components. Environmental parameters, HAST is also known as Stress Test (PCT) or Unsaturated Stress Test (USPCT).

The ideal life expectancy of LED is more than 50,000 hours, but the current actual life is far from it, which seriously affects the large-scale application of LED, and the reliability test and life prediction of LED are the key to solve this problem. Reliability testing can help LED manufacturers to timely discover the design defects of LED products and the reasons that affect their actual lifespan, so as to optimize LED products and prolong their actual lifespan.