Pixel Driving Circuit Binary Duration Control for Micro LED Gray-Scale
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Solution Overview
Problem
Micro LED display devices face challenges in achieving accurate gray-scale brightness due to limitations in current control circuits, which result in poor gray-scale display quality and color coordinate drift at low current densities.
Innovation Solution
A pixel driving circuit with a current control circuit and a time control circuit that receive display data signals and light-emitting control signals to control the magnitude and duration of the driving current, enabling binary unit duration control and improving the flexibility of duration control, thereby compensating for gray-scale brightness and enhancing display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional current control circuits are used to drive Micro LED, then the circuit structure is simple, but the gray-scale display quality is poor and color coordinate drift occurs at low current densities
Solution Approach 1:
The pixel driving circuit is divided into two independent control circuits: a current control circuit (first light-emitting control circuit) and a time control circuit (second light-emitting control circuit). This segmentation allows separate optimization of current magnitude control and light-emitting duration control, enabling precise gray-scale display while maintaining manageable circuit complexity through modular design
Solution Approach 2:
The patent implements dynamic control by allowing the time control circuit to adjust the light-emitting duration based on binary unit durations, and the current control circuit to regulate current magnitude. This dynamic dual-parameter control (current magnitude × time duration) enables adaptive gray-scale adjustment across different brightness levels, solving the color coordinate drift problem at low current densities
2Use of energy by moving object
If the driving current magnitude is reduced to achieve darker gray levels, then power consumption decreases, but color coordinate drift and gray-scale display quality deteriorate
Solution Approach 1:
The patent uses periodic pulsed light-emitting control where the light-emitting element is driven in discrete time units (binary unit durations). By controlling the number and duration of these light-emitting pulses rather than relying solely on continuous current reduction, the system achieves darker gray levels while maintaining sufficient current magnitude to prevent color coordinate drift, thus reducing power consumption without sacrificing display quality
Solution Approach 2:
The patent changes the control parameters from single-parameter (current magnitude only) to dual-parameter control (current magnitude × time duration). This allows independent optimization: current magnitude can be maintained at levels that avoid color coordinate drift, while time duration is adjusted to achieve the desired brightness level and power consumption, thereby maintaining gray-scale display quality across the full brightness range
3Illumination intensity
If the light-emitting duration is extended to achieve brighter display, then luminous brightness increases, but the flexibility of duration control is insufficient
Solution Approach 1:
The time control circuit segments the light-emitting duration into multiple binary unit durations (e.g., 1H, 2H, 4H, 8H units). This segmentation enables flexible combination of time units to achieve precise duration control for different brightness requirements, significantly improving adaptability while maintaining luminous brightness control capability
Solution Approach 2:
The patent adds a time dimension to the traditional current-magnitude-only control approach. By introducing controllable light-emitting duration as an independent dimension, the system achieves brighter display when needed while gaining flexibility through binary unit duration combinations, effectively solving the contradiction between brightness and control flexibility
Data Source
Figure 1A
Figure 1B~2
Figure 3~4
AI summary
Provided are a pixel driving circuit, a driving method thereof, and display panel. The pixel driving circuit (10) includes a current control circuit (100) and a time control circuit (200), wherein the current control circuit (100) is configured to receive a display data signal and control a magnitude of a driving current flowing through the current control circuit (100) according to the display data signal; the time control circuit (200) is configured to receive the driving current, and receive a time data signal, a first light-emitting control signal and a second light-emitting control signal, and control a flowing time period of the driving current according to the time data signal, the first light-emitting control signal and the second light-emitting control signal. The pixel driving circuit (10) can implement binary unit duration control in the case of multiple times of scans, improve the flexibility of the duration control, and thus achieve compensation for grayscale brightness, and improve the display effect of the display panel.