Micro-LED Display Manufacturing Yield Optimization

A micro-LED display device that can meet high-resolution requirements and has a high micro-LED product yield for manufacturing. The device has a circuit substrate with micro-LED units on one side and a metal conductive layer on the other. The conductive layer contacts the epitaxial layer of the micro-LEDs and has light conversion regions. A light conversion layer in some regions converts emitted light. Light-shielding structures on the epitaxial layer cover some areas. The metal layer is thicker than the epitaxial layer.

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Display device using micro-LEDs with a method to selectively separate defective micro-LED chips before assembly on the display substrate. It involves arranging micro-LEDs in different types of assembly grooves on the substrate. Micro-LEDs from the chamber are moved magnetically into the grooves. The grooves and electrodes are designed to exert different dielectrophoresis forces on normal versus defective micro-LEDs. This allows only the defective chips to be recovered while the good ones remain in place.

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Manufacturing process for an ultra-high-resolution Micro-LED micro-display screen with a simple process and few pixel defects. The process includes: providing an LED epitaxial wafer; forming isolation columns on the wafer to divide it into chip regions; placing conductive solders in the chip regions; performing a first CMP process to remove the conductive solders outside the chip regions; forming electrodes and LED light-emitting structures on the wafer; performing a second CMP process to remove upper parts of the electrodes and LED structures outside the chip regions; and removing the isolation columns to separate the chips. The process enables producing micro-displays with ultra-high pixel density and resolution suitable for AR/VR headsets.

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A method for manufacturing micro-LED display panels that simplifies the mass transfer of millions of micro-LEDs by bonding them directly to a backplane substrate through a conductive layer on the LED surface. The method starts with growing the LED epitaxial layers on a base substrate that can then be peeled off by laser lift-off. The peeled LEDs are then bonded to a backplane using a conductive layer. This eliminates the need for separate transfer steps and improves yield compared to conventional methods.

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A micro-LED display panel design allows for repairing defective pixels to improve panel yield. The driving backplane of the micro-LED display is designed with multiple spatially independent electrode pairs. The LED chips are soldered to any of the electrode pairs. If a chip in a pixel is defective, it can be desoldered and resoldered to a different electrode pair. This allows the repair of individual pixels instead of scrapping the whole panel when a single pixel is bad.

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Micro LED display module manufacturing method that improves yield by allowing replacement of defective LEDs before final assembly. The method involves pressurizing the LEDs on the substrate before curing the adhesive layer, to electrically connect them and check their operation. Defective LEDs are identified and replaced with alternatives.

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A micro LED display repair method that can increase repair yield compared to conventional methods. The repair method involves using two soldering layers in each pixel area of the display. A first soldering layer is used to bond the primary micro LED to the circuit layer. If the primary micro LED is found to be faulty, the second soldering layer is used to bond a secondary micro LED in its place. The key aspect that increases repair yield is that the first soldering layer is larger and covers the full circuit surface, while the second soldering layer is smaller and only partially covers the secondary micro LED. This allows easier alignment and bonding when replacing a faulty micro LED.

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Micro-LED with improved light extraction efficiency and manufacturing yields by shaping the LED geometry to minimize losses of side-emitted light. The micro-LED has a reflective layer surrounding a tilted side surface to redirect and extract light emitted from the sidewall. This improves total light extraction compared to conventional vertical sidewall micro-LEDs. The tilted sidewall also allows more LEDs to be grown on a substrate. The micro-LED has a vertical sidewall on one side and a tilted sidewall on the other.

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Mass transfer method and apparatus for Micro LED manufacturing. The method involves designing differently shaped Micro LED chips of different colors and matching shaped transfer cavities on a vibrating transfer mold surface. When dumped and vibrated together, each color's uniquely shaped LED chips fall into corresponding cavities. This allows mass transfer of multiple colors at once, improving efficiency exponentially while ensuring high yield.

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Micro LED display module with densely packed micro LEDs on a multilayer circuit board with minimal pads. This allows high-resolution displays with reduced thickness, improved yield and simplified bonding compared to individual LED encapsulation. The circuit board has top and bottom layers with pads matching orthographic projections of the micro LEDs. Internal layers between them provide routing. A flat insulating layer covers the LEDs. The pads connect to drive the LEDs which are arranged in a matrix.

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Micro-LED chip design for efficient red light emission using a GaAs epitaxial structure with a platform to reduce cost and improve yield compared to traditional LED designs. The platform exposes the N-type window layer on one side while embedding the second electrode in a trench on the other side, with insulation to isolate it.

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Transfer method of micro LEDs to improve manufacturing efficiency of displays by replacing whole defective modules rather than individual LEDs. The method involves transferring the micro LEDs from a donor substrate to a relay substrate, cutting it into individual modules, testing them for defects, then transferring only the normal modules to the display substrate.

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Method for manufacturing a micro LED panel using a novel process to improve yield and performance compared to conventional approaches. The method precisely calculates the number and position of micro LED chips required for each pixel region, forms those chips together on a single substrate, then transfers and fixes them all at once to the display panel. This accurate and efficient chip transfer prevents position deviations and simplifies manufacturing compared to individual transfers. The resulting micro LED panels have excellent light output performance and improved yield.

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Micro LED display manufacturing with improved yield and reliability through a structure where the light emitting layer is bonded to a support substrate before removing the growth substrate. This reduces process tact time to reduce breakage possibility.

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Manufacturing micro LED displays with improved yield and reliability by using a sol-gel glass to fill gaps between micro LED chips on a first substrate, detaching the chips from their original substrate, and bonding a second substrate on top. This avoids the need for transfer heads or complex transfer processes.

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Micro-LED display panel architecture that improves micro-LED yield by allowing pixel repair. The driving backplane of the display panel has multiple pairs of anodes and cathodes. The anode and cathode leads are shared between pixel units. This allows replacing a defective LED by simply connecting the chip to a different anode/cathode pair, instead of replacing the entire panel.

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Micro LED chip that can emit red, green, and blue light from a single chip. The chip has multiple active layers, with one layer emitting blue light and another layer emitting green light. A phosphor layer is added to convert some of the blue or green light to red light. By using a single chip that can produce all three primary colors, the complexity, yield issues, and alignment challenges of transferring multiple colored chips are avoided, simplifying production of microLED displays.

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Micro LED display technology that aims to reduce the number of mask steps and improve manufacturing yield by using transparent variable resistance materials as electrodes. The variable resistance material is used as a transparent electrode that can be made conductive by forming a filament when a voltage greater than a threshold is applied. This allows a transparent electrode to be formed on the upper semiconductor layer of each micro LED without needing a separate mask step.

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Method for transferring micro-LEDs to a receiving substrate to enable manufacturing high-quality micro-LED displays. It involves using a laser to lift-off micro-LEDs from the original substrate and transfer them to a receiving substrate. An anisotropic conductive layer makes electrical contact with the receiving substrate pads. This avoids complications of pick-up tools and multiple transfers. The laser lift-off enables easy transfer without damaging the micro-LEDs.

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Microscale LED lighting devices with repair capabilities to improve manufacturing yield. The micro LED device has a main luminescent device and a redundant luminescent device. When the main LED is functioning, the redundant LED is electrically isolated from the circuit. But if the main LED fails, the redundant LED can be activated by connecting its electrodes to the circuit using a conductive material. This provides a repair mechanism to enable failed micro LEDs to be replaced by redundant ones.

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