11 patents in this list

Updated: April 25, 2024

Micro-LED displays featuring color-tunable pixels present a groundbreaking evolution in screen technology, offering unprecedented control over color output. This emerging capability enables dynamic adjustment of each pixel's color, promising enhanced display customization and improved visual performance.

This article investigates the technological developments and strategies integral to achieving versatile color tuning in Micro-LEDs, which could lead to more vibrant and energy-efficient screens across various applications.

1.  Stacked Sub-Pixel Structure for High-Density Micro-LED Displays

Seoul Viosys Co., Ltd., 2023

Micro LED display with stacked sub-pixels to reduce interference and improve brightness. The display uses stacked sub-pixels, each containing multiple LEDs, instead of individual LEDs for sub-pixels. This allows higher pixel density with fewer LEDs per substrate. The stacked sub-pixels are arranged in a pixel with the bottom LED emitting through the top LEDs. The top LEDs reflect back emitted light from bottom LEDs to avoid color mixing. This eliminates the need for color filters. The stacked sub-pixels are electrically connected with vias. The stacked sub-pixel structure reduces interference compared to side-by-side LEDs.

2.  Adjustable Color Performance in Micro-LED Displays Through Current Pulse Control

Lextar Electronics Corporation, 2022

Display device with adjustable color performance by selectively controlling the driving current pulse amplitude and width for each subpixel's LED. This allows compensating for variation in LED peak wavelengths and improving color fidelity and reducing color deviation. The subpixels each have a LED and control circuit. The circuits provide different driving current pulse amplitudes to make the LEDs emit at the target wavelength. They also provide varying pulse widths to adjust LED brightness.

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3.  Dual Micro-LED Subpixel Design for Color Stability Across Grayscale Levels

PlayNitride Inc., 2022

Micro LED display with improved color accuracy at high brightness levels. The display has subpixels with two micro LEDs of different colors driven independently. The current ratio between the micro LEDs is adjusted based on grayscale level. This prevents color shift as driving current increases. At low grayscale, only the shorter wavelength micro LED is on. At high grayscale, only the longer wavelength micro LED is on. In between, the longer wavelength micro LED current increases relative to the shorter wavelength micro LED. This maintains consistent color appearance at all grayscales by matching dominant wavelengths.

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4.  Innovative Sandwich Structure for Color Stability in Micro-LED Displays

Shenzhen China Star Optoelectronics Technology Co. Ltd, 2018

Micro LED color display device with improved color uniformity and stability. The display has blue, green, and red subpixels sandwiched between a driving substrate and a package substrate, with a support in between. This sandwich structure allows independent optimization of each color subpixel without affecting the others. This improves color uniformity by reducing deviations from LED binning and allows easier control of green color stability compared to traditional RGB displays.

5.  Dynamic Subpixel Adjustment for Enhanced Color Accuracy in Micro-LED Displays

VueReal Inc., 2020

Micro LED display system and method for improving dynamic range, power consumption, and color accuracy. The display has individually controllable subpixels in each pixel. This allows independent adjustment of emission time and duty cycle for each subpixel. This enables optimizing power consumption and color accuracy without affecting gamma. By dynamically adjusting subpixel emission times, it tunes display color without affecting gamma.

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6.  Individually Controllable RGB LED Subpixels for Enhanced Color Gamut in Micro-LED Displays

IMAX Theatres International Limited, 2020

Active display with increased color gamut using individually controllable RGB LED subpixels to overcome limitations of fixed color bins. The display has a pixel made of multiple RGB LED subpixels. Each subpixel has individually adjustable red, green, and blue LEDs. By varying the intensity of each LED, the pixel can output light in a wider color gamut than any individual subpixel LED could achieve on its own. This allows using more LEDs from a production batch to cover a desired display color space like DCI-P3 or Rec. 2020.

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7.  Innovative Full-Color Micro-LED Display Panel with Simplified Fabrication and Enhanced Color Gamut

The Hong Kong University of Science and Technology, 2020

Monolithic full-color LED display panel with improved color gamut and simplified fabrication compared to prior art. The panel has pixels with red, green, and red subpixels, where each subpixel uses a common multi-quantum well structure. The subpixel compositions are adjusted at different current densities to emit primary colors. A conversion layer changes the third subpixel's color. This allows full-color without color conversion layers or complex assembly. The common structure simplifies fabrication versus individual RGB LEDs.

8.  Enhanced Micro-LED Display Technology with Dual-Emitter Sub-Pixels for Adaptive Color and Brightness

X-Celeprint Limited, 2017

Display system with pixels having sub-pixels with multiple heterogeneous light emitters to improve performance under varying viewing conditions. Each sub-pixel contains two different light emitters that have distinct attributes like color, brightness, efficiency, angular distribution, size, etc. By independently controlling the emitters, the display can optimize light output for different situations. For example, one emitter may have better contrast for dark scenes while the other provides better color saturation for bright scenes.

9.  High CRI Color-Tunable Micro-LED Emitter with Broad-Spectrum Phosphor Coating

LedEngin, Inc., 2016

Color-tunable LED emitter with high color rendering index (CRI) across a wide range of color temperatures. The emitter uses multiple independently addressable LED groups on a ceramic substrate, allowing the color to be tuned by adjusting the current supplied to each group. Some of the LED groups have broad-spectrum phosphor coating to improve CRI and R9 (red rendering) compared to narrow-band LEDs. This provides high CRI and R9 over the entire color temperature range.

10.  Enhanced Color Accuracy and Efficiency in Micro-LED Displays with Neutral Color Pixels

Semiconductor Energy Laboratory Co., Ltd., 2015

A light-emitting device that improves color accuracy and reduces power consumption in full-color displays by using a specialized light-emitting element that generates a neutral color. The device has pixels containing red, green, and blue light-emitting elements, as well as a neutral light-emitting element. This allows the device to display full color images by combining the primary colors and neutral color instead of having separate red, green, and blue pixels. The neutral element reduces the burden on the primary color elements, improves color reproduction, and lowers power consumption compared to using only primary colors.

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11.  Innovative Color Tunable Micro-LED Module for Customizable Display Colors

PhotonStar LED Limited, 2015

Color tunable LED module with multiple submodules and control to eliminate manufacturer color temperature binning. The module has multiple submodules, each with a blue LED and a different phosphor for a specific color emission (red, yellow, orange). This allows mixing the submodule outputs to tune the overall white color without sorting and binning LEDs. A control system adjusts the submodule intensities to achieve desired color points. The submodules are mounted on a high thermal conductivity substrate and encapsulated to isolate the phosphors. This prevents phosphor bleed between submodules. The encapsulant also improves light extraction and thermal isolation for better efficiency.

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