Pixel Circuit Time Control for Micro LED Color Stability
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Solution Overview
Problem
Current display driving solutions for micro inorganic light emitting diodes are not mature enough to support high-resolution displays, as they fail to maintain efficient light emission and stable color coordinates under varying current densities.
Innovation Solution
A pixel circuit comprising a light emitting device, a current supply sub-circuit, and a time control sub-circuit that operates the light emitting device in a high-current-density region, using a combination of current control and time length control methods to stabilize light emission and enable gray-scale display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If micro inorganic light emitting diodes are operated under low current density, then power consumption is reduced, but light emitting efficiency decreases and color coordinates become unstable
Solution Approach 1:
The patent implements periodic action by dividing the light emission into multiple sub-frames within each display frame. The light emitting device is driven at high current density for specific sub-frames and remains off or at low current for other sub-frames. This temporal modulation allows the device to operate in high-efficiency regions periodically while maintaining acceptable average power consumption and stable color coordinates through the high-current sub-frames.
Solution Approach 2:
The patent applies dynamics by making the current density dynamically adjustable over time within each frame period. Instead of operating continuously at low current density, the system dynamically switches between high current density (for efficiency and color stability) and low or zero current density (for power saving), optimizing both power consumption and performance characteristics.
2Device complexity
If conventional display driving solutions are used, then device complexity is low, but they fail to maintain stable light emission and color coordinates for micro inorganic light emitting diodes
Solution Approach 1:
The patent segments the display frame period into multiple sub-frames, with different light emitting devices assigned to different sub-frames. Each pixel circuit includes segmentation of the frame time and segmentation of current supply through switching circuits. This segmentation allows conventional circuit structures to be enhanced with minimal added complexity while achieving stable light emission and color coordinates through coordinated sub-frame driving.
3Reliability
If high current density is applied continuously, then light emitting efficiency is maintained, but power consumption increases
Solution Approach 1:
The patent implements periodic action by dividing the display frame into multiple sub-frames where light emitting devices are activated at high current density for only a portion of the frame period. Devices that are not currently displaying gray-scale information remain off or operate at minimal current. This periodic high-current driving maintains light emitting efficiency when needed while reducing average power consumption through temporal modulation.
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
The solution effectively maintains efficient light emission and stable color coordinates across different current densities, enabling the use of micro inorganic light emitting diodes in high-resolution displays by controlling the time length of light emission and current supply.
Implementation Method 1
a light emitting device... configured to receive a data voltage of the data signal terminal and provide a drive current for the light emitting device
Data Source
AI summary
A pixel circuit, a drive method, a display substrate, and a display device are provided. The pixel circuit includes a light emitting device, a current supply sub-circuit, and a time control sub-circuit. The current supply sub-circuit is connected to a scanning signal terminal, a data signal terminal, a light emitting control terminal, a first power voltage terminal, the time control sub-circuit, and the light emitting device, and is configured to receive a data voltage of the data signal terminal and provide a drive current for the light emitting device. The time control sub-circuit is connected to the scanning signal terminal, a time length signal terminal, a second power voltage terminal, a direct current control signal terminal, and a direct current voltage terminal, and is configured to receive a time length voltage of the time length signal terminal and a direct current voltage input by the direct current voltage terminal.