Dual Scan Driver Pixel Circuit for Low-Frequency Display 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 operations.

Innovation Solution

The display device employs multiple scan drivers operating at different frequencies, with shared scan signals among transistors, and separates initialization power supplies to reduce power consumption and enhance image quality, utilizing P-type and N-type transistors for efficient current control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If scan signals are supplied at high frequency to drive the display device, then the image quality is improved, but the power consumption increases

Engineering Contradiction:

Improveimage qualityVSAvoidpower consumption

Core Design Contradiction:

Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The scan driver is divided into multiple independent scan drivers (first scan driver, second scan driver, third scan driver) that can operate at different frequencies. Each scan driver controls specific pixel lines, allowing different regions of the display to be driven at different frequencies, thus reducing overall power consumption while maintaining image quality in critical areas.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different scan drivers are assigned to different pixel lines based on their specific requirements. For example, the first scan driver operates at a first frequency for first pixel lines, while the second scan driver operates at a second frequency for second pixel lines, allowing optimization of power consumption and image quality locally for each region.

Inventive Principle:

Principle #3Local quality

2Use of energy by moving object

If multiple scan drivers operate at different frequencies, then power consumption is reduced, but the device complexity increases

Engineering Contradiction:

Improvepower consumptionVSAvoiddevice complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

Each scan driver is designed with the same basic functional structure, allowing them to perform the same scanning function but at different frequencies. This modular universal design reduces the overall complexity compared to designing entirely different circuitry for each region, as the same design patterns and components can be reused across multiple scan drivers.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Speed

If scan signals are toggled frequently, then the display refresh rate is improved, but the power consumption increases

Engineering Contradiction:

Improvedisplay refresh rateVSAvoidpower consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The display device dynamically adjusts the operating frequency of different scan drivers based on the content being displayed and the required refresh rate. When high refresh rates are needed for motion content, scan drivers operate at higher frequencies; when displaying static content, they operate at lower frequencies, thus reducing power consumption while maintaining the necessary display refresh rate.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The scan drivers operate in periodic cycles, alternating between active scanning periods and idle periods. During idle periods, the scan signals are not toggled, reducing power consumption. This periodic operation allows the display to maintain high refresh rates during active periods while consuming less power overall compared to continuous high-frequency operation.

Inventive Principle:

Principle #19Periodic action

4Illumination intensity

If initialization power supplies are separated for different transistors, then image quality is improved, but the device complexity increases

Engineering Contradiction:

Improveimage qualityVSAvoiddevice complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

Different initialization power supplies (first initialization power supply, second initialization power supply, third initialization power supply) are assigned to different transistors based on their specific electrical characteristics and requirements. This local optimization ensures that each transistor is properly initialized for its specific function, improving overall image quality by reducing defects and improving uniformity across the display.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12475829B2Display device including first and second scan drivers to provide scan signals to different transistors of a pixel circuit

Publication Date: 2025.11.18 SAMSUNG DISPLAY CO LTD

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; an emission driver to supply an emission control signal to each of the emission control lines at the first frequency; and a data driver to supply a data signal to each of the data lines in response to the scan signal supplied to each of the first scan lines.