关键词: 无衬底MicroLED芯片, 直显, PM玻璃基板, AM玻璃基板

Abstract: Micro LED technology offers numerous advantages, such as high brightness, high contrast ratio, high resolution, low power consumption, and long lifespan. As chip sizes continue to decrease, research into the application of substrate-free Micro LED chips is becoming increasingly urgent. Thanks to the small dimension of substrate-free Micro LED chips, the light-emitting units account for less than 1% of the display’s total area. The increase of the proportion of the black background area can significantly improve the display’s contrast ratio. The applications of Micro LED on PM (passive matrix) and AM (active matrix) glass substrates are briefly compared. PM-driven glass substrates can achieve a minimum line width/spacing of 12 μm (compared to the 50 μm limit of traditional PCB substrates), making them suitable for even smaller chip sizes. The combination of PM glass substrates with massive through glass via and thick copper technologies strikes a balance between cost and display performance. Meanwhile, targeted design solutions are implemented to address the strength and reliability issues associated with glass substrates and have achieved the expected results. AM-driven LED displays utilize fully flip-chip high-voltage μA-level chips and a 12 V switching power supply. The high-voltage, low-current driving mode significantly reduces current density. Simultaneously, the pixel-level precise control enabled by AM driving supports independent voltage boosting in any arbitrary area, allowing for localized peak brightness display. PM and AM-driven glass substrates enable the application of substrate-free Micro LED chips in direct-view displays through different approaches, thereby driving the evolution of display technology toward ultra-high definition and low power consumption.

Key words: substrate-free Micro LED chip, direct display, PM glass substrate, AM glass substrate