Color-Shifting Micro-LED Display Color Gamut Tetrahedralization
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Solution Overview
Problem
Conventional LED-based displays face challenges in controlling both color and light intensity to provide grayscale dynamic ranges, as the color and brightness of micro-LEDs (μLEDs) change with applied current, making it difficult to generate a wide range of colors and large dynamic ranges.
Innovation Solution
The system employs color-shifting μLEDs (CS-μLEDs) that emit different colors based on current density, using PWM signals to control brightness and selecting a limited number of primary colors to produce a three-dimensional color gamut, allowing for the display of a wide range of colors through tetrahedralization and dithering techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional LEDs-based displays are used with narrow band wavelength emission, then the display structure is simple and manufacturing is easier, but the color range and grayscale dynamic range are limited
Solution Approach 1:
The patent changes the fundamental parameter of LED emission by using color-shifting μLEDs that can dynamically alter their wavelength output based on applied current density. This allows a single μLED to produce multiple colors (red, green, blue, and intermediate hues) by adjusting the current, replacing the need for multiple fixed-wavelength LEDs and complex color mixing systems.
Solution Approach 2:
The invention makes each μLED pixel multi-functional by enabling it to perform both color selection and brightness control through a single component. The color-shifting μLED can operate at different current densities to produce various colors while maintaining proportional brightness control, allowing one pixel to replace what would traditionally require multiple specialized components.
2Adaptability or versatility
If color-shifting μLEDs are used to emit different colors based on current density, then a wide range of colors can be displayed, but controlling both color and light intensity becomes difficult
Solution Approach 1:
The patent employs Pulse Width Modulation (PWM) to control the brightness of color-shifting μLEDs. By switching the μLEDs on and off at high frequencies with variable duty cycles, the system achieves precise brightness control independent of color selection. This periodic action separates the brightness control function from the color control function, making both easier to manage independently.
Solution Approach 2:
The system pre-determines a limited set of primary colors that can be generated by the color-shifting μLEDs using specific current density settings. These primary colors are selected in advance to form a color gamut that can be tetrahedralized, creating a structured color space that simplifies subsequent color and brightness control operations.
3Illumination intensity
If a limited number of primary colors are selected to form a three-dimensional color gamut, then the display achieves large dynamic range and high color saturation, but the number of displayable colors is reduced
Solution Approach 1:
The patent transitions from traditional two-dimensional color representation (chromaticity diagram) to a three-dimensional color space by incorporating luminance as the third dimension. The color gamut is tetrahedralized in this 3D space, allowing each tetrahedron to represent a specific volume of colors with defined chromaticity and luminance ranges. This dimensional expansion enables precise control over both color quality and brightness simultaneously.
Solution Approach 2:
The continuous color gamut is segmented into a finite number of tetrahedrons, each representing a discrete color volume. This segmentation allows the system to manage a large but manageable number of color states while maintaining high color saturation and dynamic range. The tetrahedralization creates a structured framework that balances color diversity with control precision.
4Illumination intensity
If conventional LED displays use multiple color channels for grayscale control, then the grayscale dynamic range is adequate, but the latency and efficiency are reduced
Solution Approach 1:
The patent extracts the grayscale control function from the color control mechanism by using PWM timing control rather than relying on multiple color channels or analog dimming. Brightness is controlled by the duration of the PWM pulse relative to the period, completely separating intensity control from color selection and eliminating the latency associated with multi-channel coordination.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables lower latency, higher contrast ratio, greater color saturation, and better efficiency by allowing the display of images with a wide range of colors and large dynamic ranges, while reducing the need for complex grayscale control.
Implementation Method 1
the display technology presented here may be based on color-shifting μLEDs (CS-μLEDs) pixels which may emit light with different colors according to the applied current
Implementation Method 2
The CS-μLEDs may comprise of III-N materials and related alloys and may be grown along a polar crystal growth direction
Data Source
AI summary
In one embodiment, a computing system may receive a target color and a propagated error for a pixel location. The system may determine an error-modified target color for the pixel location based on the received target color and the propagated error. The system may identify, based on a location of the error-modified target color in a three-dimensional color space, a subset of pre-determined colors in the three-dimensional color space. The error-modified target color may correspond to a weighted combination of the subset of pre-determined colors. The system may determine a pixel color for the pixel location based on the subset of pre-determined colors and respective weights associated with the subset of pre-determined colors. The system may determine, based on the pixel color, driving signals for light-emitting elements associated with the pixel location. The system may output the driving signals to control the light-emitting elements associated with the pixel location.