Effect of LED Chip Displacement on its Optical Performance and Reliability

The displacement of the LED chip can easily occur during chip bonding process, which is the first step of LED packaging. In this work, the effect of LED chip's displacement was studied by theoretical analysis and a series of comparative experiments, and the effects include LED's optical performance and reliability. LED modules with different chip displacement distances were packaged. The optical parameters were measured and accelerated aging tests were conducted to estimate the LED modules' reliability. The degradation curves of luminous power were fitted and the lifetimes were predicted. It was found that the chip displacement can greatly affect the optical performance and reliability of LED modules. Finally, some possible methods to eliminate the effect were brought up.