Manufacturing Cost Reduction for Micro-LED Displays

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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Mass transfer method for LED chips to improve efficiency, yield, and reduce cost compared to using PDMS adhesive. The method involves transferring LED chips from a temporary substrate to a backing substrate without using PDMS. Instead, the LED chips have patterns on sacrificial layers and support layers. The patterns allow breaking the sacrificial layers to release the chips onto the backing substrate. This avoids the need for PDMS and its limitations. The patterns can be made using photoresist layers on the substrates. The LED chips are first transferred onto a temporary substrate with glue, then to a backing substrate with another glue. The sacrificial layers are removed to break the connecting arms between the LED chips and release them onto the backing substrate.

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LED chip assembly, manufacturing method, chip transfer, and display backplane with improved yield, reliability, and flexibility. The LED chips are bonded to a carrier substrate using a sacrificial layer and high-temperature bonding layer instead of organic adhesive. This allows higher temperature processing to create the chips without limiting yield. The sacrificial layer units between chips are covered by a removable barrier layer. During transfer, only the barrier over exposed sacrificial units is removed, allowing selective chip transfer without moving all chips. This provides more compact chip layout and better yield compared to one-to-one correspondence. The display backplane uses these chips to improve yield and reliability.

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Improving the precision of mass transfer of microLEDs by modifying the surface of the chips. A sacrificial passivation layer is added above the bonding pads. The sacrificial layer has a flat surface with uniform characteristics similar to the GaN epitaxial layer. It is roughened to match the roughness of the GaN after laser stripping. This eliminates step and material differences that degrade transfer accuracy. The roughened sacrificial layer provides a consistent surface for adsorption and transfer compared to the GaN surface.

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Micro-LED display with integrated electronics on the same substrate to avoid transfer steps. The microLED chip preparation involves growing the microLED lattice and driving circuit on the same substrate. This allows integrating the microLED display and electronics without transfer steps. The closed linear power supply has the power line encircling the modules to simplify connections.

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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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RGB three-color integrated Mini-LED chip, manufacturing method, and display panel that simplify production and packaging of Mini-LED displays. The integrated chip contains all three RGB colors in a single mini LED instead of having separate red, green, and blue mini LEDs for each pixel. This reduces the number of transfer steps and improves yield compared to assembling discrete RGB mini LEDs. The manufacturing method involves growing an epitaxial layer with the three color LED layers stacked vertically. The chip is then diced to separate individual RGB integrated mini LEDs. This allows full-color displays using mini LEDs with simpler and more efficient transfer and assembly compared to discrete RGB mini LEDs.

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A stable and reliable method for transferring microLED chips to a display substrate. The method involves transferring the microLED chips to the substrate while they are still attached to supporting pillars. This prevents poor electrical connections caused by solder overflow. The pillars provide space for the molten solder to surround the microLED without bridging to adjacent devices. The pillars are later removed to leave the microLEDs firmly connected to the substrate. This improves transfer stability and reliability compared to directly transferring bare microLEDs.

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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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Transferring large numbers of micro LED chips from a growth substrate to a display substrate with improved yield by using a temporary substrate with recessed grooves to hold the micro LED chips. The micro LEDs are first grown on a wafer, then transferred to the temporary substrate with recessed grooves. The wafer substrate is removed, leaving the micro LEDs in the recessed grooves. The temporary substrate with micro LEDs is then transferred to the display substrate. This allows easier pickup and transfer of the micro LEDs due to the recessed grooves.

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A transfer structure and method for precisely moving and transferring micro LED chips to display devices with high efficiency and yield. The structure uses guide rails spaced apart from the transfer substrate with wells between them to accommodate the micro LEDs. This allows the LEDs to be scanned and guided between the rails using a liquid and absorbent material. The spacing between the guide rails is greater than the LED width to allow passage. This fluidic self assembly transfer method enables precise and automated transfer of large numbers of micro LEDs to the display substrate.

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Method for transferring micro LED chips from a growth substrate to a display backplane with improved efficiency and reduced damage compared to traditional methods using masks. The method involves using a transfer template with microstructures on one side. The LED chips are grown on the microstructures. During transfer, a laser removes the chips from the template without a mask. The microstructures prevent lateral forces from flipping or tilting the chips during laser peeling. The microstructures also prevent light from damaging the backplane. This allows direct chip-to-chip transfer without aligning masks.

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A method to transfer LED chips from their growth substrates to a display backplane without offset issues during laser lift-off and transfer. The method involves coating a non-conductive adhesive layer on the display backplane. The LED chips are transferred one at a time from their growth substrates onto the adhesive layer. The adhesive prevents offset during laser lift-off. The LED chips are then electrically connected to the backplane and pressed to form metal eutectic bonds. This allows precise alignment without shifting during transfer.

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A method to transfer micro LED chips from their growth substrate to a display backplane without multiple pick-and-place steps that can misalign the chips. The method involves spreading insulating adhesive between adjacent micro LEDs on the growth substrate. The substrate is then placed above the display backplane with a gap larger than the chip height. The adhesive is heated to soften and flow, connecting the substrate and backplane. The growth substrate is removed, leaving the micro LEDs suspended on the adhesive columns. They fall onto the backplane pads along the column channels. This prevents misalignment and provides a controlled transfer path.

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Mass transfer method for micro LED displays that allows reliable transfer of micro LED chips from growth substrate to display backplane without alignment issues. The method involves filling insulating adhesive between adjacent micro LED chips on the growth substrate, heating to soften and extend the adhesive to the display backplane, separating the micro LED chips from growth substrate, then pressing to drop onto backplane pads via the adhesive column. This prevents misalignment and falling off. The adhesive has shapes like trapezoids or columns with gaps between chip and adhesive to avoid obstruction during bonding.

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Micro-LED chip with stacked LED units to reduce the number of transfers needed to create displays. The chip has two staggered LED units, one stacked on top of the other. This allows three primary colors to be formed by alternating red, green, and blue stacked LEDs instead of transferring three separate monochrome chips for each pixel. The chips have metal backing layers and planarization layers to facilitate manufacturing.

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Method for manufacturing Micro & Mini Micro-pitch LED display modules with very small pixel pitches (less than 0.5 mm) that overcomes limitations of conventional LED display technology. The method involves a unique packaging process using substrates with ball-bonded chips and flip-chip ICs. The display is made by stacking and bonding a top substrate with LEDs and a bottom substrate with flip-chip ICs using solder balls. This allows high-density, ultra-small pitch LED displays to be manufactured without the need for complex multi-layer substrates or physical resolution limits. The method involves steps like silk screening solder paste, soldering balls, applying flux, and reflowing to connect the chips and ICs.

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Manufacturing method for a red light Micro-LED chip that allows creating a substrate-free Micro-LED chip to improve yield and efficiency compared to conventional methods. The method involves growing the red LED structure on a temporary substrate, then transferring it to a receiving substrate using a specialized technique called microtransfer printing. This involves picking up the LED structure using a stamp with suction cups, moving it to the receiving substrate, and releasing it. The stamp conforms to the LED structure shape to avoid damage during transfer. After printing, the temporary substrate is removed, leaving the red Micro-LED chip on the receiving substrate.

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A method to improve transfer efficiency and yield of micro LED displays by transferring multiple colors from a temporary substrate to an array substrate simultaneously instead of separately. This reduces the overall number of micro LED transfers for an array compared to transferring each color separately. By transferring all required colors at once, it eliminates multiple transfers for each color when fabricating the display. This improves transfer efficiency and yield compared to traditional methods that involve multiple transfers for each color.

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A mass transfer method for transferring large numbers of micro LED chips from a growth substrate to a receiving substrate with high efficiency and accuracy. The method involves forming grooves on the growth substrate sidewalls to capture each micro LED assembly. The grooved growth substrate is then bonded to a transfer substrate by heating to soften and flow the transfer substrate material, which fills the grooves and wraps the micro LED sidewalls. This transfers the micro LEDs to the transfer substrate. Finally, the micro LEDs are transferred from the transfer substrate to the receiving substrate by aligning protrusions on the transfer substrate with grooves on the receiving substrate. This allows precise transfer of the micro LEDs. The grooves on the growth substrate provide alignment and bonding benefits during the transfer steps.

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Micro-LED chip structure and preparation method to enable high yield, low cost transfer of large numbers of micro-LEDs for displays. The structure has a thin transparent conducting layer on top of the LED epitaxy. This allows electrical contact to multiple LEDs through a single electrode pad. The thin conductive layer enables good electrical connection while preventing short circuits between adjacent LEDs. The preparation method involves growing the LED epitaxy and then adding the thin conductive layer on the finished wafer. This allows transferring many micro-LEDs together by adhering to a carrier substrate and peeling off the wafer. The thin conductive layer allows electrical connection through the carrier substrate. This enables high yield transfer of large numbers of micro-LEDs without individually handling each tiny device.

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A method, device, and system for transferring micro LED chips with high efficiency, simplicity, and feasibility. The method involves attaching the micro LED chip to a transfer head using an electromagnetic force, then moving the head to a destination substrate, and releasing the chip onto the substrate using the electromagnetic force. This allows direct chip transfer between wafers and substrates without intermediate carriers, reducing complexity and cost compared to intermediate substrate methods. The transfer head is attached to a transfer plate with a controller to automate the process.

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A method to transfer large numbers of tiny LED chips from a donor wafer to a target substrate without damaging them. The method involves forming a polyimide (PI) film on the LED substrate and then peeling off individual LED chips using the PI film as a release layer. This allows selective transfer of the micro-LEDs without the high-temperature die bonding process that can damage small chips. The PI film is used to grip and lift the micro-LEDs off the donor wafer for transfer to the target substrate.

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Fabricating hybrid devices with functional III-V semiconductor chips like microLEDs by bonding tiles of chips from a separate III-V wafer to a control wafer instead of bonding whole wafers. The method involves processing a III-V wafer to form multiple functional chips integrated on it. Tiles of chips are defined on the III-V wafer, each tile containing a cluster of chips. The III-V wafer is diced to separate the tiles. The III-V tiles are then bonded to a separate control wafer containing the circuitry for the chips. This allows using differently sized wafers for the functional chips and control circuitry, which can have better yield and bond quality compared to bonding whole wafers.

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A method to manufacture a three-color LED display with improved efficiency and yield by reducing the number of welding steps and improving reliability compared to conventional three-color LED display manufacturing processes. The method involves simultaneously transferring and soldering all three colors (blue, green, red) of LED chips onto the display board in a single step, instead of separate steps for each color. This eliminates the need for multiple transfers and welding passes, reducing process complexity, time, and risk of LED damage.

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Micro LED display manufacturing method, micro LED display, and micro LED display manufacturing apparatus that addresses the mass transfer problem of manufacturing micro LED displays. The method involves transferring pre-fabricated micro LED chips from their growth substrate to a temporary substrate, and then transferring the micro LEDs individually from the temporary substrate to the final display substrate. This allows efficient transfer of millions of micro LEDs using techniques like laser lift-off or mechanical pressurization. The temporary substrate with circuits provides a staging area to handle and position the micro LEDs before final assembly on the display substrate. The display substrate can then be reflowed to fix the micro LEDs in place.

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Efficiently transferring micro LEDs to a large-size display substrate using interposer technology to enable mass production of large micro LED displays. The method involves transferring micro LEDs to wells on an interposer using fluidic self-assembly, aligning the interposer with the display substrate, injecting a penetrating solvent between them, and vaporizing the solvent to transfer the micro LEDs to the display substrate. This allows transferring many micro LEDs at once and repeating the process for large displays. An interposer with blister layers can also be used for laser-assisted transfer.

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A simplified method for manufacturing microLED displays that reduces the complexity and cost of transferring large numbers of microLED chips from a source substrate to a destination substrate. Instead of direct or indirect transfer methods, the microLEDs are first transferred to an intermediate substrate using a technique like electrostatic adsorption. The intermediate substrate with the microLEDs is then bonded to the destination substrate. After bonding, the intermediate substrate is removed, leaving the microLEDs on the destination substrate. This eliminates the need for complex and expensive direct or indirect transfer methods involving bonding and peeling steps.

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Assembly method for LED displays using monolithic LED strips instead of discrete chips for smaller pixel sizes and simplified manufacturing. The method involves forming a monolithic LED strip on a substrate, separating it with a transfer layer, and transferring it to an display backplane. Guide strips are also added between the LED strip and backplane to aid alignment. This allows larger, easier-to-make LED strips to be used instead of tiny discrete chips for high resolution displays.

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LED chip assembly, display panel, and preparation method that provides a new solution for arranging alignment marks on the transient substrate used during LED chip mass transfer. The solution involves growing the marking bases along with the LED chips on the original substrate. This allows transferring both the LED chips and marking bases together to the transient substrate. The marking bases are used for positioning during the final transfer to the driving substrate. This avoids needing to separately transfer the marking bases after assembly. It improves mass transfer efficiency by reducing the number of transfers and improving alignment consistency.

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Massive transfer method for LED chips to improve yield and efficiency of transferring large quantities of LED chips between substrates. The method involves dissolving the first adhesive layer bonding the LED chip to the first substrate in a solvent, allowing the chip to detach, and then removing the first substrate. This prevents the first adhesive from hindering chip transfer to the second substrate. The chips are immersed in the solvent to dissolve the first bonding layer, then the first substrate is removed. This allows clean transfer of the chip to the second substrate without resistance from the first bonding layer.

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Micro LED transfer head using vacuum suction to move and place micro LEDs between substrates. The transfer head has a suction member with vertical pores to suck micro LEDs and a support member with arbitrary pores to distribute vacuum force. This allows selective transfer of micro LEDs by vacuum while preventing damage to unused areas. The vertical pore size is larger than LED size to ensure all LEDs are sucked. The support member pore structure helps transmit vacuum pressure. The head can transfer micro LEDs from one substrate to another with precise alignment and efficiency.

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Chip fabrication and transfer method, display backplane, and display device that addresses the limitations of using organic adhesives for chip bonding. The method involves transferring chips using a vacuum pickup mechanism instead of adhesives. The display backplane has chip bonding areas where the vacuum pickup device can directly pick up and place the chips, avoiding the need for organic adhesives. This simplifies and improves yield and reliability compared to adhesive bonding. The display device uses this backplane with better cost, yield, and reliability.

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A method for manufacturing micro LED displays with improved yield and reduced cost compared to conventional methods. The method involves transferring micro LED chips directly from their growth substrate to a separate substrate with drive circuits and bonding pads. This allows mass transfer of the active LED chips without the complexity and yield issues of epitaxially growing and processing the entire display on a single substrate. The transferred micro LED chips are fixed in place and connected to the drive circuits. This allows using optimized growth substrates for each color of LED and simplifying display substrate processing.

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A low-cost method for transferring micro-LED chips to display backplanes, avoiding the need for mass transfer methods that consume material and increase cost. The method involves using a transfer substrate with a patterned adhesive layer. The micro-LED chips are first attached to the adhesive areas of the transfer substrate. The transfer substrate is then aligned with the display backplane and the micro-LED chips are transferred to specific locations using rollers or a stamping tool. The transfer substrate is then peeled off, leaving the micro-LEDs properly positioned on the display backplane. The patterned adhesive prevents the micro-LEDs from shifting during transfer.

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A manufacturing method for micro LED displays that solves the mass transfer problem of transferring large numbers of microscopic LED chips from a growth substrate to a display substrate. The method involves directly transferring the micro LED chips from their growth substrate onto the display substrate without intermediary steps. This is achieved by using specialized equipment to pick up and place the micro LED chips onto the display substrate with precision alignment. This allows transferring thousands or millions of micro LED chips from the growth substrate to the display substrate in a single step, avoiding the time-consuming and low-yield process of transferring individually. The method involves using a platform with XY and Z stages to move the growth substrate with micro LED chips over the display substrate. The micro LED chips are picked up from the growth substrate and placed onto the display substrate using a specialized tool. This allows accurate alignment and transfer of the micro LED chips

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Method for manufacturing micro LED displays with improved productivity and reduced cost compared to transferring individual micro LEDs one by one. The method involves using stretchable stamps with elastic pillars to pick up and transfer multiple micro LEDs at once. The stamps can be stretched to separate the LEDs by a wider interval than the spacing on the source wafer. This reduces the number of transfers needed to fill the display. The stretchable stamp allows multiple LEDs to be picked up simultaneously, stretched apart to the desired spacing, and then transferred to the display substrate.

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Method for high yield, high throughput transfer of micro-LED chips to displays using stretchable stamps. The method involves picking up multiple spaced apart micro-LED chips with a stretchable stamp, stretching the stamp to further space apart the chips, and then transferring the stretched chips to a target substrate. The stretchable stamp has elastomeric material that can be stretched in multiple directions. This allows the chips to be transferred with reduced spacing and fewer steps compared to picking up one chip at a time.

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Efficient and convenient method for transferring micro LED chips to display backplanes. The method involves growing micro LEDs on a substrate, forming a concave shape in the adhesive layer covering the micro LEDs, and bonding a support structure to the epitaxial layer in the concave. This allows the micro LEDs to be picked up directly from the transfer substrate by disengaging from the support structure, avoiding the need for debonding the adhesive layer. The support structure is broken when the micro LEDs are picked up, separating from the chip.

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Method for manufacturing a display device using micro LED chips that enables rapid, efficient, and accurate transfer of micro LED arrays to display panels. The method involves separating the micro LED chips from a wafer using etching, transferring them to a carrier substrate, and then selectively transferring some chips to a sacrificial layer substrate. Finally, the micro LED arrays on the sacrificial substrate are transferred to the display panel. This allows sequential transfer of micro LED arrays from the sacrificial substrate to the display panel instead of transferring individual micro LEDs from the wafer to the display panel.

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A chip transfer method for high efficiency mass transfer of micro LEDs from a donor substrate to a target substrate. The method involves using a stretchable layer with wavy fibers to pick up and transfer multiple micro LEDs at once. The stretchable layer is attached to the micro LEDs on the donor substrate with controlled fiber spacing matching the LED spacing. After separation, the stretchable layer with multiple LEDs is transferred to the target substrate, then the fibers are removed. This allows transferring an entire array of LEDs at once instead of repeated pick-and-place.

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Efficient transfer method for micro LED chips from a growth substrate to a display backplane without debonding an adhesive layer. The transfer involves removing part of the adhesive between the transfer substrate and micro LED chips, leaving a support. When picking up the micro LED chips, the unremoved adhesive breaks, detaching the chip. This simplifies transfer compared to fully adhered chips requiring debonding. The method enables easier, faster, and cheaper micro LED display manufacturing by avoiding complex debonding steps.

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Photosensitive transfer resin for selectively transferring micro LED chips between substrates using UV exposure and heat expansion. The transfer resin is applied to the chips and exposed through a mask to form a degradation layer in some areas. Heating expands the degraded regions to peel off those chips while leaving the others attached. This allows selective transfer of some chips from a substrate to another. The expansion offsets the adhesive force of the resin. The transfer process can be repeated to move chips between carriers and display panels. The expansion force of the photosensitive resin replaces the need for mechanical peeling.

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Chip transfer assembly, chip transfer method, and display backplane for efficient microLED transfer. The chip transfer assembly has a transfer substrate with bonding assemblies for multiple microLEDs. Each assembly has a chip bonding member with a sacrificial layer. When transferring microLEDs from growth substrate to display backplane, the sacrificial layer is dissolved instead of debonding the adhesive. This leaves a support column that weakens bonding. MicroLEDs pickup is easier as they and the column detach together. The support column prevents embedding the sacrificial layer in the adhesive. This avoids debonding steps for microLED transfer convenience and efficiency.

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Efficient and convenient method for transferring micro-LED chips between substrates, such as from a growth substrate to a display backplane. The method involves fracturing a support body beneath the micro-LED chip using force, instead of using adhesives, to detach the chip from the substrate. This eliminates the need for debonding adhesive layers during transfer, simplifying the process and improving efficiency compared to using adhesives.

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Method to manufacture displays with micro LEDs that improves yield, throughput, and resolution compared to pick-and-place methods. The method involves selectively transferring micro LEDs from a carrier substrate to a thermal release substrate using heat, then sequentially transferring the micro LEDs from the thermal release substrate to the display panel. This allows transferring only a subset of the micro LEDs from the carrier substrate to the thermal release substrate, improving yield by avoiding damage and misalignment during transfer. The thermal release substrate can then be peeled off to transfer the selected micro LEDs to the display panel. This enables sequential transfer of micro LEDs from the thermal release substrate to the display panel, improving throughput compared to pick-and-place.

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Weakening structure for micro LED chips to improve efficiency of mass transfer. The structure involves connecting bridges between adjacent micro LED chips that are still bonded to a substrate. These bridges provide temporary connections to prevent scattered chips during mass transfer. They also fix the chip position for easier handling. After transfer, the bridges are broken to separate the chips. This allows precise chip selection and positioning during transfer, improving efficiency compared to randomly falling chips. The weakening structure enables quick and accurate mass transfer of micro LED arrays.

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Preparing a Mini-LED display module using a transfer method to reduce manufacturing costs. The method involves transferring the Mini-LED chips from their original substrate to a flexible membrane using a pick-and-place machine. The flexible membrane acts as an intermediate transfer step to move the Mini-LEDs to their final destination in the display. This allows separating the time-consuming and expensive process of directly transferring the Mini-LEDs from their growth substrate onto the display circuitry. The Mini-LEDs are first picked from their growth substrate and transferred to the flexible membrane. Then, they are picked again and transferred to the display circuitry. The flexible membrane allows handling and positioning of the Mini-LEDs separately from the display assembly. This improves yield and reduces the complexity and cost of transferring the tiny Mini-LEDs directly from the growth substrate.

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Bulk transfer micro LED display technology that improves efficiency, yield, and precision of transferring large numbers of micro LEDs compared to conventional methods. The technique involves creating a transfer module with integrated driving electronics and LED chips arranged in an array. This allows transferring multiple micro LEDs at once rather than individually. The array is then attached to the display backplane using perimeter contacts. This reduces transfer steps, improves precision, and avoids issues like packaging adhesive peeling and thermal mismatch. The display screen uses a backlight with a quantum dot layer and a packaging module over the micro LEDs.

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Low-cost processing technique for manufacturing Micro-LED flexible touch displays that reduces the production cost compared to conventional methods. The technique involves transferring multiple Micro-LED wafers to the target substrate using an elastic film with magnetic powder and an electromagnet. This allows batch transfer of many Micro-LED wafers at once, instead of individually transferring each wafer. The elastic film conforms to the target substrate shape during transfer. The magnetic powder adheres to the Micro-LEDs on the temporary substrate. The electromagnet then pulls the Micro-LEDs off the temporary substrate and onto the target substrate. This simplified batch transfer method reduces production steps and costs compared to individually transferring each Micro-LED wafer.

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