Screen Refresh Rate Switching Within One Frame to Prevent Tearing

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Solution Overview

Problem

Conventional display technologies experience image tearing and freezing due to delays during dynamic changes in screen refresh rate, particularly in scenarios requiring high frame rates.

Innovation Solution

A method for controlling dynamic screen refresh rate changes by directly sending refresh rate switching instructions through a new path within a frame period, involving a refresh rate decision making module, SurfaceFlinger, and display driver integrated circuit (DDIC) to synchronize frame and refresh rates, ensuring rapid transitions without delays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the screen refresh rate is dynamically switched to a high refresh rate in dynamic display scenarios, then the smoothness of the image is improved, but image tearing and freezing occur due to long delay during switching

Engineering Contradiction:
Improvescreen refresh rateVSAvoidimage display stability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The system performs preliminary detection of dynamic display scenarios (such as sliding operations or high frame rate applications) and proactively switches the refresh rate before the actual dynamic content appears. This advance preparation ensures that when dynamic content is displayed, the screen is already operating at the appropriate high refresh rate, eliminating the delay that causes tearing and freezing effects

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamic adjustment of the screen refresh rate based on real-time detection of display scenario characteristics. The system continuously monitors for dynamic display conditions and adapts the refresh rate accordingly, transitioning from static refresh rate settings to dynamic, scenario-based adjustment. This enables the display system to optimize performance for each specific scenario while maintaining stability

Inventive Principle:
Principle #15Dynamics

2Loss of time

If the screen refresh rate switching delay is reduced to prevent image tearing, then the responsiveness is improved, but the system complexity increases due to additional control modules and interfaces

Engineering Contradiction:
Improverefresh rate switching delayVSAvoidcontrol system structure
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent introduces a refresh rate decision making module as an intermediary between the SurfaceFlinger and the display driver. This module receives scenario category information, determines the appropriate refresh rate, and generates switching instructions. By inserting this intermediate decision layer, the system achieves rapid refresh rate adaptation without requiring complex direct control mechanisms between higher-level software and hardware components

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The control system is segmented into distinct functional modules: scenario detection module, refresh rate decision making module, and execution interface. Each module has a specific responsibility, allowing the system to achieve complex dynamic refresh rate control through coordinated simple operations. This modular segmentation reduces overall system complexity by dividing the control function into manageable, independent components

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4266302B1Method for controlling dynamic change in screen refresh rate, and electronic device
Publication Date: 2026.01.28 HONOR DEVICE CO LTD
  • EP4266302B1 patent drawingFigure 1
  • EP4266302B1 patent drawingFigure 2
  • EP4266302B1 patent drawingFigure 3

AI summary

This application relates to the field of display technologies, and provides a method for controlling dynamic change of a screen refresh rate and an electronic device. In a scenario of dynamic change of the refresh rate, a refresh rate switching instruction may be sent immediately through an added refresh rate setting interface (displaySetFps) within a current ith frame period before a current Vsync periodicity ends. After receiving the refresh rate switching instruction, a DDIC drives a display screen (such as an OLED) to switch a screen refresh rate, and then the DDIC returns a new TE signal. After receiving the new TE signal, SurfaceFlinger starts a new Vsync periodicity corresponding to a switched screen refresh rate. In an embodiment of this application, a switching speed at which the screen refresh rate is switched may be increased by adding a new path. For example, it may be ensured that each switching of the screen refresh rate is completed within one frame. This reduces a delay and prevents image freezing to some extent.