Maximizing Electroluminescence Intensity in Single-Ended Electrical Contact Micro-LEDs: A Strategy for Optimizing Driving Waveforms

The continuous miniaturization of micro-LEDs poses challenges for yield testing using electrical contact probes. Single-ended electrical contact micro-LEDs (SEC-LEDs), as a special noncontact alternating current (ac) device, have advantages, such as not relying on probes and simple electrode design. It also solves the carrier injection problem in traditional ac drive LEDs, making it have great potential in the field of nondestructive testing of chips. However, the low luminous intensity of SEC-LED is still the bottleneck problem restricting the application of SEC-LED in the field of detection. In this study, an optimized driving waveform strategy is proposed to enhance the electroluminescent intensity of SEC-LED from a driving technology perspective. By establishing an equivalent circuit model and combining simulation analysis of its working mechanism, the impact of circuit parameters on current is further analyzed, leading to the derivation of corresponding current-domain equations. The simulation and experimental results illustrate that a higher rate of voltage change and a larger circuit capacitance are advantageous for increasing the forward peak current of SEC-LED. Square waves, with their highest rate of voltage change over time, have been identified as the optimal driving waveform for achieving high luminous intensity in SEC-LED. When driven by square waves at the optimal frequency point, the peak luminous intensity is increased by up to 266% compared to traditional sine wave driving. Therefore, this proposed optimization strategy effectively enhances its luminous performance and holds broad application prospects in micro-LEDs high-precision detection fields.