Optical Modules for Micro-LED Displays

Monolithic integration of light emitting structures that generate different colors of light on a single substrate. The technique involves growing light emitting structures, each with a laterally terminated active area, on a substrate with buffering layers made of GaN. The active areas of different structures emit different colors. A p-doped GaN layer covers each active area. This allows monolithic integration of red, green, and blue LEDs on a substrate for applications like displays. The GaN buffering layers enable epitaxial growth of high quality LED structures on the substrate.

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Micro-scale LED structure for high efficiency micro LED displays that allows for easy fabrication and packaging. The LED structure has a distributed Bragg reflector (DBR) in the insulation layer covering the LED sides. This reflects light back into the LED instead of leaking out. The DBR is thicker on the top surface than the sides to prevent uneven reflections. This improves efficiency by preventing side surface light escape. The DBR-coated LEDs are used in micro LED displays where the DBR-coated LEDs are subpixels in a unit pixel. The pixels are arranged on a transparent substrate with a light blocking layer to form the display.

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Integrated circuit components with glass interposers and micro-LEDs for high-speed, low-loss short-distance communication between integrated circuits. The components have micro-LED assemblies mounted directly on the IC dies and connected to waveguides in the glass interposer. This allows high-frequency signals to be sent/received optically through the glass interposer at close range without long copper traces. The micro-LEDs can operate at elevated temperatures and low energy levels.

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LED device and light-emitting apparatus with miniaturized LED chips for high resolution displays. The LED device has multiple LED chips, an electric circuit layer assembly, and an encapsulating layer. The encapsulating layer covers the LED chips and circuit assembly. This allows the LED chips to be defined into pixel sizes for high resolution displays. The LED devices can be arranged on a circuit board to make a compact light-emitting apparatus with high pixel density for display applications.

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Micro LED structure and display device with optical structures for improved light patterns in applications like augmented reality and virtual reality. The micro LED structure has multiple micro LED chips, each with a stacked semiconductor layer, metal pad, and reflective coating. Optical structures are placed over each micro LED chip. A planarization layer surrounds the micro LEDs. The optical structures enhance the light extraction efficiency from the micro LEDs for better AR/VR performance.

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Display device using micro-LEDs with improved brightness uniformity and reduced power consumption by surrounding the micro-LEDs with a scattering layer. The scattering layer surrounds the bonding layers connecting the micro-LEDs to the substrate. This prevents the micro-LEDs and scattering layer from overlapping when transferring the micro-LEDs, which can cause misalignment and uniformity issues. By surrounding the bonding layers with scattering, it extracts more light from the micro-LEDs and provides consistent brightness from all viewing angles.

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Abstract Micro lightemitting diodes (MicroLEDs) are regarded as the core of nextgeneration display technology due to their high brightness and energy efficiency. However, reduction in size MicroLEDs has led increased manufacturing challenges exacerbated issues such sidewall emission, which hinder development highpixeldensity displays. This paper proposes a vertically stacked MicroLED design based on an Lshaped metal wall structure, aiming suppress emission enhance top light extraction efficiency (LEE). Through parameter scanning, dimensions thickness epitaxial layer optimized. Combined with inclined sidewalls reflective structure wall, optical characteristics red, green, blue analyzed using raytracing simulations. The is significantly reduced (with maximum 68.04% compared without walls), enhanced (the LEE within 90 direction for blue, red by 196.18%, 51.69%, 3.45%, respectively, walls). simulation results demonstrate potential fullcolor displays, providing new approach suppressing crosstalk improving performance.

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Full-color monolithic InGaN micro-LEDs can achieve the transfer of full-color subpixels through a single flip-chip bonding process, offering advantages such as simplified fabrication processes and reduced production costs for micro-LED display. In this paper, we demonstrate structure that utilizes pseudo-quantum well to long-wavelength red emission, which is applied micro-LEDs. Subsequently, present micro-LEDs, stack (R), green (G), blue (B) epitaxial layers tunnel junctions. The entire grown epitaxially by metal organic chemical vapor deposition. Micro-LEDs with mesa size 2020 m 2 RGB are fabricated. exhibits emission peak wavelength 650 nm at an injection current density 1 A/cm , dominant approximately 620 nm, achieving true emission. Even under 100 it still maintain over 600 nm. broad color gamut coverage their significant potential applications in

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Display device with improved efficiency and contrast by using optimized nanostructures for light extraction from the wavelength conversion layers. The display has pixels with red, green, and blue subpixels. Each subpixel has a wavelength conversion layer and color filter. The nanostructures are arranged in periodic patterns matching the wavelengths converted by the conversion layers. This enhances light extraction efficiency by resonance and light localization effects near the nanostructures.

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MicroLED display with improved color conversion efficiency and reduced manufacturing cost. The display uses microLEDs with 3D structures on the emitting surface that extend into the device. Cavities are formed between the structures and filled with optical conversion material. This allows deeper cavity depths for better absorption/conversion of light. It also enables higher concentration of conversion material without thickness limitations. The microLEDs have regular 3D structures extending from the emitting surface into the device. These structures define cavities filled with optical conversion material for improved light absorption/conversion.

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Backlight module for displays that improves uniformity of light emission from micro LED arrays. The module uses feedback control to balance brightness across multiple micro LEDs driven by individual chips. Each micro LED has a shared positive terminal and a chip terminal connected to its negative terminal. Each chip has multiple control terminals, a feedback node per terminal, and a signal acquisition unit to collect feedback voltages. An adjustment module uses the feedback to balance brightness by adjusting chip control signals. This compensates for variability in micro LED currents due to differences in resistance.

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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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Anti-aliasing technique for microLED displays that improves image smoothness by adjusting brightness levels within individual pixels. The technique uses microLED displays with each pixel containing a group of three differently colored microLEDs covered by a scattering plate. By controlling the brightness of the individual microLEDs inside a pixel, it allows gradual color transitions between pixels for smoother images compared to using fixed color filters.

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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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Using microLED arrays in applications beyond just displays, like augmented reality (AR) and virtual reality (VR) devices, by integrating compact light sources made of microLED arrays into these devices. The microLED arrays provide smaller, more efficient light sources compared to traditional light sources. This allows for improved AR/VR devices with better display brightness, contrast, and power efficiency.

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MicroLED display to prevent crosstalk and improve brightness by inserting blocking regions between each color conversion region. The blocking regions prevent light from one subpixel leaking into adjacent subpixels, reducing crosstalk. This is achieved by forming the microLED structure with separate pores for the color conversion regions and additional blocking regions in between. The color conversion material is filled in the color conversion pores and the blocking regions are left empty. This prevents light from one subpixel leaking into adjacent subpixels, reducing crosstalk.

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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 apparatus with a pixel structure that allows combined light emission and light sensing in each subpixel. The pixel has subpixels, at least one of which has a light-emitting and light-receiving device instead of a regular light-emitting device. This allows the display to emit light and also detect light in the same subpixel. This enables multifunctionality like displaying an image and sensing light simultaneously. The light-emitting and light-receiving device has a structure with electrodes for emitting and sensing light.

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Display device with integrated components in the display area and an opening for other components. The display has a substrate with an opening surrounded by a display area. Grooves are formed between the opening and display using a layer with different etch selectivity compared to the main insulating layer. This allows etching grooves without damaging the display elements. It enables integrating components like sensors or cameras into the display while preventing contamination of the display area.

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