Wide Color Gamut LED Pixel with Screen-Door Reduction
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Solution Overview
Problem
Large direct-view LED displays face challenges in achieving a wide color gamut for cinematic applications due to variations in RGB LED packets, leading to low yield and high costs, as few packets support DCI-P3 or wider color gamuts, and the 'screen door' effect is not adequately addressed with traditional LED configurations.
Innovation Solution
An active display using a group of RGB LED packets, each forming a sub-pixel, with individually adjustable intensities, selected from specific bins to achieve a wide color gamut by modulating light through pulse-width modulation, allowing for a wider color gamut like DCI-P3 and potentially augmented to cover Rec. 2020, with a custom filter for calibration and precise intensity control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional tri-color LED packets are used for display, then the device complexity is low, but the color gamut is limited and cannot support wide color spaces like DCI-P3
Solution Approach 1:
The pixel is segmented into multiple LED packets (typically 4 packets per pixel) instead of using a single tri-color LED packet. Each packet can have different chromaticity characteristics, allowing the combination to achieve wider color gamut while maintaining manageable complexity through modular organization.
Solution Approach 2:
The display combines multiple LED packets with different chromaticity properties (different bin selections) to create a composite light output that achieves wider color gamut. By selecting packets from specific bins with complementary chromaticities, the system synthesizes a broader color space than any single packet could provide.
2Manufacturing precision
If four LED packets per pixel are used to reduce screen-door effect, then the image quality improves, but the number of LED packets increases from 9 million to 35 million, resulting in low yield and high cost
Solution Approach 1:
The patent applies different chromaticity characteristics to different LED packets within the same pixel based on their bin selection. By strategically selecting packets from specific bins with appropriate chromaticities, each packet contributes locally to the overall color gamut while maintaining brightness uniformity across the display.
Solution Approach 2:
The system changes the chromaticity parameters of individual LED packets by selecting from different manufacturing bins. This allows packets with varying color characteristics to be combined, expanding the overall color gamut while maintaining compatibility with standard color spaces through controlled parameter variation.
3Measurement precision
If careful selection of RGB LED packets is performed to achieve wide color gamut, then the color precision improves, but the selection yield decreases and cost increases
Solution Approach 1:
The system dynamically adjusts the intensity of individual LEDs within each packet through pulse-width modulation (PWM) and individual LED control. This dynamic control allows packets with varying chromaticities to be balanced, achieving wide color gamut while accommodating a broader range of manufactured packets, thereby improving selection yield.
Solution Approach 2:
The patent implements a calibration system that measures the actual chromaticity and intensity of each LED packet and uses this feedback information to adjust control parameters. This feedback mechanism enables the system to compensate for manufacturing variations, achieving precise color reproduction without requiring extremely tight manufacturing tolerances.
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 increases the fraction of usable LEDs from a production batch, reduces the 'screen door' effect, and provides a cost-effective solution for wide color gamut displays by maximizing intensity balance between LEDs, achieving high color precision and uniformity for most colors while tolerating some brightness imbalances in extreme colors.
Implementation Method 1
Large direct-view light-emitting diode (LED) displays
Implementation Method 2
Each LED packet includes at least a red primary color LED, a green primary color LED, and a blue primary color LED
Implementation Method 3
with individually adjustable intensities, selected from specific bins to achieve a wide color gamut by modulating light through pulse-width modulation
Data Source
AI summary
An active display can have an increased color gamut and include a group of LED packets that each form a sub-pixel and that together form a pixel for the display. Each LED packet includes at least a red primary color LED, a greed primary color LED, and a blue primary color LED. Each LED can be associated with an intensity value to control the intensity of primary light outputted by the LED. The group of LED packets can output light in a color gamut of a color space for the active display. Each LED packet of the group of LED packets, individually, is configured to output light in the color gamut of a subset of the color space. The active display can display a visual media presentation to an audience. An increased fraction of LEDs from a production batch can be used in the active display.