High Temperature Operating Lifetime and Temperature Cycling Tests of MicroIC-Driven MicroLED Displays

The real-world application of microLEDs and microICs in displays and related devices requires that the products be robust to demanding environmental stresses. This study investigates the reliability of a microLED display that was designed and built to serve as the pixelated light source within a liquid-crystal-on-Silicon (LCOS) projection display for augmented reality (AR) systems. Two types of reliability tests, high temperature operating life (HTOL) and temperature cycling (TC) were conducted on six microLED displays from three different fabrication campaigns. The yield, brightness, and electrical currents were measured to characterize the performance of the display pixels before and after reliability tests. All the display samples passed HTOL and TC tests with slight current changes and varying levels of brightness variation. This study provides novel and encouraging results regarding the reliability of transfer-printed microscale LEDs and ICs, and the novel interconnection methods used to assemble the displays.