Process Uniformity in Micro-LED Manufacturing

Micro LED display device and manufacturing method that prevents moisture and dust intrusion to improve reliability. The micro LED display has a pixel layer with individual micro LEDs facing the circuit substrate. A support structure extends from the substrate to the pixel layer and protrudes above it. This forms a space between the support and pixel layer. A connection layer is filled in this space and covered by a protection layer. This enclosure around the pixels prevents moisture and dust from reaching the LEDs and degrading their performance.

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LED display with improved chip attachment method to prevent positional deviations during welding. The display is manufactured by mounting LED chips on a substrate, filling the gaps between the chips with a curable material, exposing and developing the material to create grooves exposing the chip electrodes, filling those grooves with conductive paste, and adding an insulating layer. This prevents solder paste beads from moving the chips during soldering. The display has a flush filling layer, exposed chip electrodes, filled grooves connecting to the chips, and an insulating layer covering the filled grooves.

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Display module with improved bonding accuracy for micro LEDs. The module has a substrate with a region around the pixel area having higher surface energy. When bonding micro LEDs to the substrate electrodes, an adhesive layer is temporarily cured to move the excess adhesive from the pixel area to the higher surface energy region. This reduces thickness variation and misalignment of the micro LEDs compared to uniform adhesive. The higher surface energy area helps hold the micro LEDs in place during curing. The thinner adhesive between the electrodes reduces voids and gaps.

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Micro LED display device with simplified manufacturing by using a transparent substrate with pre-transferred micro LEDs, and forming the TFT electrodes on top using an organic TFT layer instead of transferring the micro LEDs onto TFT electrodes. This allows easier micro LED transfer and simplifies the manufacturing process compared to conventional micro LED displays. The device has a transparent substrate with exposed micro LED anode and cathode electrodes, a signal supply line layer on top, and an organic TFT layer with driving transistors on the supply lines.

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A method for making a micro LED display panel that reduces the likelihood of metal lines breaking when connecting the micro LEDs to the driving circuit. The method involves forming the lower electrode on the lower end of the micro LED first, and then forming the upper electrode on the upper end. This way, the metal line connecting the upper electrode to the driving circuit doesn't have to climb a slope over the height differential between the lower and upper ends of the micro LED. This reduces the risk of the metal line breaking.

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Selective transfer of microLEDs to avoid defective pixels in displays. The method involves selectively transferring microLEDs from a growth substrate to a display substrate, rather than growing and transferring the entire array. It involves depositing an adhesive layer on the growth substrate with some microLEDs exposed. A backplane is deposited on the adhesive layer aligned with the exposed microLEDs. The backplane with connected microLEDs is then transferred to the display substrate. This allows avoiding defective microLEDs from the growth substrate and improving display yield.

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Micro LED display manufacturing method to prevent crosstalk and color mixing between subpixels. It involves using opaque materials between the subpixels to block light emission. The opaque material is deposited to fill gaps between the micro LEDs and extend vertically higher than the LEDs. This prevents light leakage from one subpixel to another. The opaque material can be removed around the LED tops to expose them. This prevents color conversion material from adjacent subpixels curing onto the wrong LEDs during manufacturing. The opaque material can have low UV transmission but high visible transmission blockage.

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Method for manufacturing LED displays with micro/nano LEDs that allows easy assembly of small LEDs on a substrate. The method involves forming a base circuit on the substrate, covering it with an electrode layer, forming an insulating layer over the entire area, creating a trench-shaped LED array area in the insulating layer, and supplying LEDs in fluid form. Applying voltage to the electrodes aligns the LEDs in the array. The insulating layer is removed to expose the LED contacts, which are then connected to the electrodes. This allows precise positioning of micro/nano LEDs without physically transferring them.

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Micro LED display panel with integrated multi-color LED pixels to improve efficiency and reduce production cost compared to assembling monochrome LEDs. The method involves forming a stack of layers containing different color LED materials on a substrate, patterning them to expose the bottom conductive layer, then selectively etching to expose sidewalls and form separate pixels with stacked LED structures. This allows integrated multi-color pixels in each display area.

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Microdisplay chip with precise alignment and reduced volume when transferring LED chips to a PCB. The microdisplay chip has a transfer substrate with grooves for each LED chip. The LED chips are placed in the matching grooves on the transfer substrate. This prevents chip shifting during transfer and ensures accurate alignment when bonded to the PCB. The grooves also limit the LED chip thickness to prevent protrusion from the PCB. The LED epitaxy, current spreading layer, and bonding layers are all contained within the grooves. This reduces the overall display chip size.

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Method for manufacturing a display array using micro LEDs that avoids the need for patterning the LED dies. The method involves forming a semiconductor stack on a substrate with insulating layers and electrode pads directly contacting the stack. The stack, insulating layers, and electrode pads are transferred to a driving backplane where the electrode pads connect to the backplane through openings in the insulating layers. The stack is energized by the backplane to emit light from the unpatterned stack regions defined by the electrode pads. This allows dense arrays of micro LEDs without die patterning by using contact electrodes that penetrate the insulating layer.

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Active full-color MicroLED display device with improved yield and manufacturing efficiency by integrating the MicroLED array and driver circuitry on a single silicon substrate instead of transferring pre-made MicroLEDs. The device has a silicon substrate with an epitaxial layer of LED material on one side. MicroLEDs are formed on the epitaxial layer by etching. A pixel driving circuit is prepared on the other side of the substrate. This avoids the complex and low yield microtransfer method of attaching pre-made MicroLEDs to a display backplane.

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LED display with improved resolution, brightness, and efficiency by stacking micro LED elements vertically between electrodes. The micro LEDs are arranged in parallel to the substrate plane with gaps between them. This allows more micro LEDs per pixel area compared to horizontally aligned ones. It also reduces interference between pixels and improves light directionality. The stacked micro LEDs are connected to top and bottom electrodes. This avoids needing electrodes between each micro LED. The vertical alignment and connection scheme enables dense micro LED integration and reduces defects from transfer or missing elements.

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Method for manufacturing LED-based multi-viewpoint display devices that enables making thin and flexible displays with improved resolution and contrast. The method involves transferring basic LED chips directly onto a transparent support plate with integrated microlenses, rather than onto a separate support plate followed by attaching microlenses. This eliminates the need for a separate support plate and reduces thickness. Electrical connections are made to the chips through the transparent support. The microlenses are already integrated into the support plate, improving display quality.

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Integrated LED chip with improved reliability and yield by growing micro LED epitaxial wafers in each micro LED region surrounded by passivation. This avoids etching to define micro LED areas and reduces damage. The micro LED wafers are mesa etched with bosses. Driving structures are placed next to the mesas to avoid blocking light. Electrodes connect between the mesas and driving. This simplifies chip preparation compared to mass transfer or monolithic bonding.

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Efficiently forming micro LED displays by transferring micro LED wafers to a large transfer substrate with gaps between wafers. The gaps are larger than the initial micro LED spacing. This allows populating the display backplane in fewer steps compared to traditional methods. The micro LEDs are transferred in stages using the gaps: initial transfer for each color, gap fill rows, gap fill columns, and cross gap fill for each color. This reduces the number of transfer steps from hundreds to less than 20.

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Micro LED display chip, manufacturing method, and device that avoids brightness non-uniformity and mura issues in micro LED displays. The method involves growing the micro LED epitaxial layer on a patterned substrate with protrusions and recesses. The LEDs are formed in the recesses aligned with the protrusions. This ensures consistent LED quality, brightness, and efficiency since the LEDs grow in the same crystal orientation as the recesses. The LED array made on the patterned substrate is then connected to a backboard to create the micro LED display chip.

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Mass transfer method for micro LED displays that improves yield and reduces displacement errors during transfer. The method involves partially etching the original substrate with the micro LED array still attached. Then a temporary substrate is bonded to the micro LED side. Final etching completes the transfer by lifting off the original substrate through the temporary substrate. This sequential etching reduces micro LED loss and displacement compared to direct etching.

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Micro-LED microdisplay with separate n-GaN mesas to avoid optical crosstalk and cracking issues compared to continuous n-GaN layers. The display has an array of Micro-LED chips bonded to a CMOS driving substrate using a redistribution layer. The Micro-LED chips are made by etching separate n-GaN mesas surrounded by etched p-GaN and InGaN/GaN quantum wells. This allows passivation and electrode wiring after separating the n-GaN without cracks. The redistribution layer connects the Micro-LED chips to the CMOS substrate instead of bonding the continuous n-GaN.

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Efficient and accurate transfer of micro LED chips onto a driving substrate for displays using a wafer-level preprocessing and packaging technique. The method involves extracting micro LED crystals from a wafer, placing them into square tubes, arranging the tubes in a pixelated array, cutting the array into sheets, and attaching the sheets to a driving substrate. This allows large numbers of tiny LEDs to be precisely transferred and assembled into displays using a wafer-level packaging process instead of pick-and-place.

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