Dual-Scan Display Pixel Driving for Low-Frequency Power Saving
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Solution Overview
Problem
Existing display devices face challenges in reducing power consumption and improving image quality, particularly in low-frequency driving modes, due to inefficiencies in scan signal toggling and transistor configurations.
Innovation Solution
Implementing a dual-frequency driving system with separate scan drivers for first and second scan lines, utilizing P-type and N-type transistors, and separating initialization power supplies to reduce power consumption and enhance image quality by optimizing scan signal timings and transistor operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If scan signals are supplied at high frequency, then productivity is improved, but power consumption increases
Solution Approach 1:
The scan driver is divided into multiple stages (first scan driver and second scan driver) that operate at different frequencies. The first scan driver operates at a first frequency for normal driving, while the second scan driver operates at a second frequency (lower than the first) for power-saving mode. This segmentation allows the system to switch between productivity-oriented and power-saving operations without compromising overall display functionality.
Solution Approach 2:
The system dynamically adjusts the scanning frequency based on display requirements. When displaying static images, the scan frequency is reduced to the second frequency to save power. When dynamic content is displayed, the system switches to the first frequency for high productivity. This dynamic frequency adjustment resolves the contradiction between maintaining high productivity and reducing power consumption.
2Use of energy by moving object
If scan signal toggling is reduced in low-frequency mode, then power consumption is reduced, but image quality deteriorates
Solution Approach 1:
In low-frequency driving mode, the scan signals are supplied periodically at the second frequency rather than continuously at the first frequency. This periodic action reduces the number of signal toggles and transitions, thereby reducing power consumption while maintaining adequate image refresh for static or slowly changing displays. The periodic nature ensures that images are still updated regularly enough to maintain quality.
Solution Approach 2:
The system changes the frequency parameter of scan signals based on display content characteristics. For static images, the frequency is changed to a lower second frequency, reducing toggling and power consumption. The parameter change is controlled to maintain minimum quality thresholds, resolving the contradiction between power savings and image quality.
3Reliability
If initialization power supplies are separated, then image quality is improved, but device complexity increases
Solution Approach 1:
Different initialization power supplies (first and second initialization power supplies) are provided for different portions or functions of the pixel circuit. This local differentiation allows optimized initialization for specific transistor groups, improving image quality by reducing leakage and ensuring proper threshold voltage setting. The added complexity is localized to the power supply configuration rather than the entire display system.
Data Source
AI summary
A display device including pixels coupled to first scan lines, second scan lines, emission control lines, and data lines; a first scan driver to supply a scan signal to each of the first scan lines at a first frequency to drive the display device at a first driving frequency, and to supply the scan signal to each of the first scan lines at a second frequency to drive the display device at a second driving frequency lower than the first driving frequency; a second scan driver to supply a scan signal to each of the second scan lines at the first frequency to drive the display device at the first driving frequency, and to supply the scan signal to each of the second scan lines at the second frequency to drive the display device at the second driving frequency; and an emission driver to supply an emission control signal.