Micro-LED Display Repair

A manufacturing method for replacing defective light-emitting elements in dense arrays without damaging adjacent elements. The method involves irradiating the adhesive layers between the elements with ultraviolet light. The UV exposure reduces the adhesion of the irradiated areas. This allows selectively removing the defective element while leaving the adjacent elements attached due to the stronger adhesion.

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Display device with a blocker structure to prevent circuit substrate damage during repair of micro LED displays using laser removal. The display has a blocker on the substrate with pads for the micro LED electrodes. The blocker has sides aligned with the connecting pads. This prevents laser light from the micro LED removal process from reaching and damaging the substrate through the pads. The blocker shields the substrate while the micro LEDs are removed and replaced.

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Inspection apparatus and method for detecting and managing defective pixels in displays like LED panels. The apparatus uses an external device with a camera to capture images of the display, identify defective pixels based on low luminance, and store their locations. The display device can then limit electrical signals to those pixels to prevent incorrect lighting. This enables targeted mitigation of defective pixels without affecting normal ones.

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A component processing apparatus for efficiently transferring and repairing components during mass transfer of micro LED displays. The apparatus has a carrying unit to hold the object being processed, a control unit to define processing areas, and a processing module with a transfer unit and repair unit. The transfer unit arranges components in sequence across the areas, while the repair unit synchronously removes or replaces components in each area. This allows repairing transfer failures without separate steps, reducing time and costs compared to post-transfer repair.

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Backlight unit, display device, and driving method for detecting and recycling defective LEDs in an array. The backlight has a driver circuit with a sensing multiplexer (MUX) connected to the LED emitting nodes. By selectively sensing voltage on each node and comparing, it can determine if a specific LED is defective. This allows targeted replacement of just the bad LED rather than replacing the entire array when defects occur.

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Electroluminescence display with a repair structure that allows repairing defective pixels without darkening them. The repair involves connecting the defective pixel to a nearby normal pixel rather than making it black. When a pixel fails, a laser cuts the semiconductor layer of the defective pixel. Then, repair electrodes are connected between the cut semiconductor and the nearby normal pixel's driver. This allows the defective pixel to be driven by the normal pixel's transistor. The repair electrodes overlap the emission area to prevent damage to the LED. The laser used for cutting has low energy suitable for semiconductor processing, avoiding damage to the LED.

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In this work, the degradation in luminous characteristics of red, green, and blue (RGB) micro-LEDs (10 m 10 m) under electrical stress at 360 K has been investigated. After 280 h aging, AlGaInP-based red exhibit a 31.7% reduction maximum external quantum efficiency, which is significantly greater than reductions observed InGaN-based green micro-LEDs. Specifically, peak wavelength redshift by 0.6 nm, blueshift 1.0 0.5 nm for RGB micro-LEDs, respectively. The color purity decreases 3.6% 0.7%, respectively, resulting 7% gamut.

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A display device with improved yield by sensing and repairing defective subpixels in an LED display. The display has regular subpixels with LEDs and repair subpixels. In the regular subpixels, a sensing layer is placed between the LED and insulation layer. If an LED is not transferred, the sensing layer shorts to the high potential power line. In the repair subpixels, an additional LED is placed on the insulation layer. This allows detecting and repairing subpixel LED non-transfers without full display testing.

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A transparent display module and apparatus with improved manufacturing, inspection, and repairability for self-emitting transparent displays. The module has a grid pattern on a transparent substrate, with micro-pixel ICs and inorganic LEDs placed at the grid intersections. Transparent areas are left between the grids. This allows easier manufacturing, inspection, and repair compared to traditional dense pixel layouts. The transparent areas simplify inspection by providing clear areas to see through the display. The grid pattern allows efficient repair by isolating damaged pixels to just the grid surrounding them.

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Display panel and device design with reversible mini LED soldering for multiple repairs without damaging the substrate. The display uses conductive connectors made of a thermoplastic material with conductive particles distributed in it. These connectors are used to solder mini LEDs to the substrate pads. The thermoplastic property allows easy peeling of LEDs for repairs without damaging the substrate. When cooled, the connectors solidify and hold the LEDs securely. This enables repeat LED replacements without substrate damage.

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Apparatus and method for reworking ultra-small LED chips to quickly and accurately remove defective chips from a substrate and replace them with good chips. The rework involves using transfer technique with stick-shaped detach and attach press heads with adhesive layers of varying strengths. The detach head removes misaligned/defective chips from the weaker first adhesive layer on the substrate to a stronger second adhesive layer. The attach head replaces them from a weaker third adhesive layer onto the first layer. Driving units move the heads above the substrate in X,Y,Z. This allows efficient and precise reworking of ultra-small LED arrays without misalignment issues during chip transfer.

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Self-assembly apparatus for semiconductor microLED displays that allows resolving assembly defects after self-assembly. The apparatus has a fluid chamber to accommodate a fluid and microLEDs. An assembly substrate with electrodes is immersed in the fluid. A magnet array applies a magnetic force to guide microLED assembly. Power is supplied to the electrodes to attract microLEDs. After assembly, a repair substrate with pair electrodes is fed into the fluid. Power is applied to the pair electrodes to attract misplaced microLEDs from the assembly substrate. The repair substrate is then removed. This allows extracting and repositioning misassembled microLEDs without disassembling the display.

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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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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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