Micro-LED Display Repair

Repairing techniques for micro LED displays to increase yield and reduce cost when defective micro LEDs are found after transfer to the system substrate. The techniques include replacing defective micro LEDs with spare ones, converting color of spares to match defects, mapping spare locations, and spatial coordinate variation to mitigate visual artifacts. It also involves calibration to correct for spatial non-uniformity induced by repair techniques.

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Repairing techniques for micro LED displays to increase yield and reduce costs by leveraging spare devices instead of physical replacement when micro LEDs fail. The repair techniques include remapping data from defective subpixels to surrounding spare subpixels, converting spare subpixels to match defective subpixel colors, and compensating for defective subpixel brightness in spare subpixels. The goal is to improve display quality without adding extra micro LEDs.

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Abstract InGaN red micro-LEDs were fabricated with indium tin oxide (ITO) and metal n-electrode designs. Micro-LEDs ITO electrodes achieved a peak on-wafer external quantum efficiency of 2.1% (at 1.25 A/cm2) wall-plug 1.7% 0.64 A/cm2), representing 1.6 times 1.5 improvements compared to metal-based electrodes. Improved performance was attributed the transparency ITO, enabling light extraction, while block emission. Both configurations low leakage current density ( 107 high emission wavelength around 650 nm. These results represent strong potential for low-power consumption required/area-limited AR/VR applications.

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Transferring micro-LEDs using a stamp with shape memory polymer nanotips to pick up and release the devices. The stamp has nanotips that can selectively adhere to the micro-LEDs due to shape memory properties. The nanotips heat to a critical temperature, contact the LED, press to attach, cool below critical temp, align on substrate, then heat again to transfer. This allows precise pickup, placement, and repair of micro-LEDs.

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MicroLED display technology with improved yield and production efficiency by selectively removing defective microLEDs before transfer to the final substrate. The method involves testing the microLEDs on a temporary substrate, removing any failures, and then transferring the remaining good microLEDs to the permanent display substrate. This prevents filling gaps with extra microLEDs, which can have lower yield. The key is controlling the transfer and removal rates so more defective microLEDs are removed than replaced.

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Method for manufacturing LED devices that enables efficient mass transfer, selective transfer, and repair of LEDs between substrates. The process involves attaching the LEDs from a source substrate to a carrier, removing the source substrate, and then transferring a portion of the LEDs from the carrier to the target substrate using laser lift-off. In selective transfer, the laser is focused only on the LEDs to be detached. This allows targeted replacement or repair of LEDs without disturbing the rest.

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An allGaNbased monolithic activematrix microLED system that integrates metalinsulatorsemiconductor highelectronmobility transistors (MIS HEMTs) with lightemitting diodes (LEDs) is demonstrated. The proposed structure employs direct electron injection from the 2D gas (2DEG) in a HEMT, serving as ntype layer, into quantum wells of LEDs. A 2HEMT1LED pixel configuration fabricated one epitaxial growth, enabling precise control LED light output through combination select and drive HEMTs. achieved maximum optical density 0.5 Wcm 2 . 2 matrix constructed row column lines connected via HEMTs, demonstrating capability for individual control.

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Abstract Microlight emitting diode (LED) based LED on silicon (LEDoS) is a promising candidate for nextgeneration AR and VR displays due to superior pixel performance potential high resolution. Traditional RGB pixels are placed single plane, which limits the To overcome this, vertically stacked using heterogeneous monolithic 3D integration (M3D) have been explored. However, previously reported vertical LED not considered heat dissipation capability of pixels, indeed important in future micro displays, utilized materials incompatible with standard CMOS processes, further limiting their practicality LEDoS. The critical regions constraint, bonding medium, typically organic polymer materials. Therefore, handle issue, fullcolor LEDs demonstrated oxide (SiO 2 ) yttrium (Y O 3 ), as mediums. These CMOScompatible offer thermal conductivity at least 10 times higher than conventional polymers. InGaN/GaN blue bonded oxides show improved management, leading external quantum efficiency (EQE) better color characteristics, including narrower full width half maximum (FWHM) purity. ... Read More

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Display device with improved reliability and repairability by preventing or substantially preventing dark spot defects in subpixels. The display has separate first and second conductive patterns that are electrically disconnected from each other. The subpixel electrodes are also disconnected from each other. This allows replacing a reversed connected defective LED without removing it. A laser is used to cut the connections between the electrodes and underlying conductive patterns, then connect them in the correct forward direction. This allows reusing the defective LED by changing its driving current direction. Having multiple sub-electrodes per end of the LED provides redundant current paths to improve reliability.

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Display device with improved transfer process for LED arrays to prevent defects when transferring the LEDs to the display panel. The display device has an adhesive layer on the panel with selective areas that adhere to the LEDs. During transfer, a mask is used to cure and prevent adhesion on the selective areas. This allows transferring only the LEDs in contact with the adhering areas while avoiding transfer of unplaced LEDs. The non-adhering areas provide space for LED repositioning. The adhesive force is higher on the LED contact areas. This prevents transfer defects like LEDs going to wrong positions.

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Transparent display device with improved resolution and repair capability. The display has sub-pixels containing red, green, and blue LEDs, along with a reserve sub-pixel with stacked red, green, and blue LEDs. If any LED in a normal sub-pixel fails, the reserve LEDs can replace them. Stacking the reserve LEDs reduces area compared to parallel LEDs. The reserve LED electrodes are transparent to allow light from lower LEDs to escape. This allows repair and area savings while maintaining light output.

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Display device with easily replaceable parts for improved repairability and recyclability compared to sealed devices. The display has a display panel sandwiched between an inner plate and a support plate. Coupling members connect the inner plate and support plate. This allows disassembly and replacement of just the inner panel or support plate without disturbing the rest of the display. The main frame holds the display panel and has features like guides, fasteners, and a bottom frame for securing the display. This enables easy removal and replacement of just the display panel or inner components, facilitating repair, recycling, and disassembly.

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Display panel design that allows continuous operation of a display device even if one of the gate driving circuits fails. The display panel has two gate driving circuits, one on each side, that provide gate pulses to the display's gate lines. If one driving circuit starts to malfunction, the other circuit takes over and provides single-fed gate pulses to the affected gate lines. This prevents image defects and improves reliability by allowing the display to keep functioning when one gate driver fails.

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Flexible electronic device with overlapping bumps for improved repairability of large display tiles. The device has a substrate with adjacent through holes and overlapping bumps. The bumps are adjacent along a direction. The electronic element is overlapped with the substrate and electrically connected to one of the bumps. The distance between the through holes is different from the distance between the bumps in the overlapped direction. This allows replacing a damaged bump without removing the undamaged bump and element. The substrate separates the replaced bump from the element.

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Transfer method for micro flip chips that allows reusing original bonding positions after defective chips are removed. The method uses conductive adhesive as the bonding material between the micro flip chips and substrate. Laser irradiation separates defective chips by causing gasification of the adhesive, without damaging the substrate contacts. The adhesive absorbs laser energy and expands, generating airflow to lift off the chips. This immediate separation prevents contact damage from prolonged laser exposure.

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Micro LED display element with reduced missing pixel defect and improved yield. The element has multiple LEDs packaged together with common electrodes and pads. This allows bonding all LEDs at once instead of separately. The shared electrodes and pads eliminate interference and misalignment issues during die bonding. It also reduces bonding time compared to individual LEDs. The larger element size enables repair through vacuum adsorption holes.

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Detecting defective pixels in an image array using statistical analysis on sets of surrounding pixels. For each pixel, a cell with neighboring pixels is analyzed statistically. If the statistical distance of the pixel from the cell exceeds a threshold, it indicates a defective pixel. This provides a way to detect defective pixels without relying on calibration or edge detection, as the statistical outlier can be identified on-the-fly during image processing.

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Micro light-emitting diode devices (microLEDs) have the potential to lead next generation of displays. However, their integration for achieving high brightness is severely limited by challenge low external quantum efficiency (EQE). Another limiting factor such Lambertian emission, which requires secondary optics beam emitted light in defined directions. To address these limitations, we introduce metallic and dielectric metasurfaces improve outcoupling control emission directionality blue LEDs with micrometer size. The proposed mechanism relies on interaction between multiple wells (MQWs) supporting collective resonances that result from coupling localized nanoparticles throughout array. We implemented a hexagonal diffraction lattice resonant Al SiO2 LED achieve reshaping far-field electroluminescence, thus demonstrating capabilities emitters. expand validate approach small (even at sub-micrometer scale), integrate subdiffraction into device's architecture. Implementing design allows us generated enhanced emission.

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Display panel and device design to save space and improve repairability by eliminating the need for backup electrodes in LED displays. The panel has electrode pads with three areas: a main area for the LED, and two connecting areas. If an LED fails, the connection between the main and connecting areas can be disconnected by melting the lower melting point connecting area. This allows moving the LED to the spare connecting area without needing a separate backup pad. The reduced width connecting areas save space compared to separate backup pads.

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Display panel design with improved yield and repairability. The display panel has an array of light-emitting elements on one side of a substrate. Each light-emitting element has a first binding electrode connected to a first pad and a second binding electrode connected to a second pad in the pixel region. The area of the first pad projection exceeds twice the first binding electrode projection, and the second pad projection exceeds twice the second binding electrode projection. This reduces alignment difficulties and enables bonding the replacement element within the original pixel region without repairing the pads. The larger pad areas simplify repair compared to redundant pads. The display has improved yield and repairability without impacting resolution.

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