Optical Modules for Micro-LED Displays

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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Front light module for displays that improves visibility in bright ambient light conditions. The module has a light guide plate with microstructures on the exit surface, and an assembly with thin adhesive layers on either side of an optical film. This reduces interfacial reflections when light exits the guide plate and enters the display, compared to using air gaps. Thicker adhesive on the ambient light side further reduces reflections. This prevents glare and visual interference from external light.

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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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LED lamp panel design and manufacturing technique to improve lighting, contrast, and yield while reducing cost. The panel uses a composite circuit layer with reflective layers and window structures to isolate and fill the gap around each LED chip with higher reflectivity material. This captures more light from the chip and prevents absorption by the substrate. The composite layer also allows modulating the light distribution and intensity around the chip. The technique can be used for applications like backlight displays and RGB direct view panels.

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Backlight module for displays with corner brightness compensation structures to improve uniformity and prevent dark corners. The module has a light guide plate, an optical film, and a light guide device. The light guide device extends along one side of the guide plate. It has a portion facing the light source to receive light and another portion at the corner. This guides light from the source to the corner to compensate for lower brightness there.

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Compact, lightweight optical system for imaging devices with reduced size and weight compared to conventional six-element lenses. The system uses a metalens instead of one of the glass lenses. The metalens is made of nanostructured materials and can provide similar optical performance. The metalens is sandwiched between two glass lenses. This allows reducing the overall thickness and weight of the optical system compared to six glass lenses. The metalens can have non-coaxial nanostructures in adjacent layers. The metalens also has an antireflection film.

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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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Display device with improved image quality and prevention of separated reflective sheets between substrate and lens. The display has a hole in a reflective sheet covering the substrate, with a lens inside the hole. The hole boundary has straight and curved sections. The lens body overlaps an end of a protrusion extending from one of the straight sections into the hole. This catches the protrusion to prevent separation between the reflective sheet and lens during vibrations.

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A light-emitting element transfer stamp and manufacturing method for pickup and placement of micro-LEDs without complex spring structures or high voltages. The stamp has adhesive layers in grooves that protrude above the stamp. This allows selective picking up of micro-LEDs from a growth substrate by adhesion force, then releasing to transfer onto a target substrate. A passivation layer prevents sticking between layers. The stamp material has thermal expansion matching the LED substrate. The stamp has a buffer layer with thermal conductivity between the stamp and a heater wire. This enables local heating for stamp deformation and release of the LEDs. The stamp structure allows micro-LED transfer without complex springs or high voltages.

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Display apparatus with integrated anti-peep and illumination functionality to reduce thickness and improve efficiency compared to adding separate components. The display has a light guide plate with two opposing emitting surfaces. The display panel is on one surface and the other surface reflects illumination light to the panel. Microstructures on the other surface reflect anti-peep light through the panel surface. This integrates the functions on the same plate instead of adding extra components.

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Packaging design for optical interconnects that allows vertical transmission between stacked optical components using integrated lenses and reflectors. The packaging involves bonding optical interposers and optical packages vertically aligned with lenses between them. The reflectors in each interposer are aligned vertically to transmit light between the packages. This enables vertical optical transmission between stacked optical components using integrated lenses and reflectors instead of through-the-substrate techniques.

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Arrangement and method for simplified assembly of compact optoelectronic devices like microLED displays with improved uniformity and reduced tilt. The devices have small-sized semiconductor components with side walls insulated and absorbing to prevent tilt. They are mounted on a carrier with a transparent output element and connected via an insulating layer. The components' contacts are electrically accessed from the rear. This allows easier assembly of small-pitch arrays with uniform radiation and reduced crosstalk. The method involves applying the components, insulation, and output element on a carrier, then connecting the contacts.

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Micro LED display panel design to improve display quality by reducing aberrations and crosstalk between subpixels. The key idea is to surround the LED chip with a symmetrical void in the prism layer. This ensures equal distances between the LED and void in the transverse and oblique directions. The symmetry allows the light rays to reflect identically in both directions, preventing asymmetric focal planes and reducing astigmatism. It also prevents light crosstalk between subpixels by reflecting the rays back into the LED instead of spreading them.

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Light emitting module with reduced stray light on the irradiation surface. The module has a lens over the light source, and a cover over the lens. The cover has three regions: an inner region where light from the lens enters, a middle region around the inner region with higher diffusion, and an outer region. This configuration reduces stray light by having the cover's middle region with higher diffusion surrounding the inner region where light from the lens enters, preventing light from escaping sideways.

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