10 patents in this list

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Micro-LED displays, with their self-emitting pixels promising superior color, brightness, and contrast, are positioned as a potential successor in display technology.

Achieving micro-LED display uniformity requires setting consistent brightness and color across millions of these small LEDs, but this is still a complex operation. Micro-LEDs are meant to create an immersive experience. However, because of their erratic behavior, the brightness and color of the screen might change dramatically.

1. Micro-LED display device and manufacturing method for improving display quality

PlayNitride Display Co., Ltd., 2023

Micro-LED display device and manufacturing method for improving display quality by reducing visible boundaries between adjacent regions. The device has a display substrate divided into arranged areas with splicing areas between them. Micro light-emitting elements are bonded to conductive pad pairs on the substrate. The splicing areas have filling positions alternating between two groups. 

In each transfer step, micro-LEDs are moved from a carrier to the substrate, with the transfer pattern leaving gaps for subsequent transfers to fill. This creates areas on the substrate where the LEDs have different offsets from the pads, blurring the boundaries between arranging areas when the display operates.

2. Driving LED-based displays with high color depth, power efficiency and reduced brightness variation

Meta Platforms Technologies, LLC, 2023

Driving LED-based displays with high color depth, power efficiency, and reduced brightness variation, especially for micro-LED-based displays like those in AR/VR headsets. The display uses separate digital drive circuits on a silicon wafer and analog drive circuits on an indium-gallium-zinc-oxide (IGZO) layer between the micro-LED wafer and silicon wafer. This allows optimizing the digital and analog circuits using different processes. The analog circuits in IGZO have a higher voltage, lower leakage, and better uniformity for driving micro-LEDs, while the digital circuits on silicon generate control signals. The separation with level shifters avoids large transition regions.

3. Preventing non-uniformity of luminous properties of micro-LEDs

POINT ENGINEERING CO., LTD., 2023

Method for manufacturing a micro-LED display that prevents non-uniformity of luminous properties. It involves segmenting the first substrate into regions and transferring the micro-LEDs from each region to different second substrates. This prevents uniform non-uniformity of luminous properties of the micro-LEDs on the first substrate from being transferred to the second substrate.

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4. Improve micro-LED display uniformity by transferring micro-LEDs from a transfer substrate to a target

SAMSUNG ELECTRONICS CO., LTD., 2022

This is a method for transferring micro-LEDs from a transfer substrate to a target substrate to improve display uniformity. The method involves sequentially transferring micro-LED blocks from the transfer substrate to the target substrate. The key aspect is to ensure that the direction of the micro-LED electrodes in the second block matches the direction of the first block. This helps minimize luminance and chromaticity differences at the block boundaries. This is accomplished using different transfer substrates with micro-LEDs having electrodes in different directions.

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5. Micro-LED display panel pixel structure that improves display quality

AU Optronics Corporation, 2022

Micro-LED display panel pixel structure that improves display quality by optimizing luminance uniformity between pixels. The pixel uses a reflective layer with transmissive windows on the micro-LED. The reflective layer surrounds the micro-LED encapsulated in a transmissive filling material. The transmissive windows allow light from the micro-LED to directly pass through the reflective layer. The windows farther from the micro-LED have larger areas to compensate for light attenuation. This provides uniform luminance across pixels.

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6. Patterned substrate design for growing uniform micro-LED epitaxial layers with consistent wavelength

KONKA GROUP CO., LTD., 2022

A patterned substrate design for growing uniform Micro-LED epitaxial layers with consistent wavelength. The substrate has grooves to collect excess epitaxial material during growth. By preventing the excess material from centrifugal force, it avoids uneven thickness that causes variable wavelength. The grooves improve the uniformity and spectral consistency of Micro-LED epitaxy. This enables high-yield Micro-LED production with uniform wavelength across devices.

7. Minimizing variations in luminance and chromaticity at the boundaries between blocks

SAMSUNG ELECTRONICS CO., LTD., 2021

Transfer micro-LEDs from the growth substrate to the target substrate to minimize luminance and chromaticity variations at the blocks' boundaries. This is done by using transfer substrates with micro-LEDs oriented in different directions.

8. Improved uniformity of overall optical properties of a displayed image from micro-LEDs

AU Optronics Corporation, 2020

Pixel structure for display panels that can improve the uniformity of overall optical properties of a displayed image from micro-LEDs. The pixel has a micro-LED surrounded by a sidewall structure filled with a light-transmissible material. A reflective layer on top has windows that transmit light. The micro-LED projects upward onto the reflective layer. The windows further from the projection area are larger, adjusting the aperture ratio of the reflective layer to balance brightness between pixels.

9. Micro-LED color display device with improved color uniformity and stability

Shenzhen China Star Optoelectronics Technology Co., Ltd., 2019

Micro-LED color display device that improves color uniformity and stability. The display has an array of blue, green, and red sub-pixels. Each sub-pixel contains a micro-LED. The key feature is a support layer between the driving and package substrates. This support layer helps separate the sub-pixels and reduce color crosstalk. It prevents the peak wavelength shift in one color sub-pixel from affecting adjacent sub-pixels. The support layer improves green color stability and overall color uniformity of the display.

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10. Micro-LED display panel that improves display quality

PlayNitride Inc., 2018

Micro-LED display panel that improves display quality by reducing pixel defects and improving color uniformity compared to conventional micro-LED displays. This is achieved by connecting two micro-LEDs in series within each pixel, with one having a dominant wavelength in a specific color range. If one has a defect or a different wavelength, the other can compensate for displaying the intended color by using series-connected pairs of micro-LEDs.

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It's nevertheless challenging to maintain uniformity in color and brightness across millions of micro-LEDs, despite recent improvements in the industry. Correcting this irregularity is the only way to get the immersive viewing experience that micro-LED display uniformity improvement delivers.