Always-On Display Scan-Rate Switching for Image Ghosting Control
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Solution Overview
Problem
Always-On Display (AOD) panels experience noticeable image ghosting and transitional flicker when transitioning from low On-Pixel Ratio (OPR) to high OPR images due to panel hysteresis and slow scan rates, which increases power consumption as the central control must remain active to mitigate ghosting.
Innovation Solution
Utilizing a multi-scan rate-capable AOD display panel that briefly displays high OPR images at a high scan rate before switching to a lower scan rate, with frame insertion and intensity adjustments to minimize ghosting and flicker, allowing the central control to enter sleep mode during the transition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the AOD panel uses a low scan rate to maintain power efficiency, then power consumption is reduced, but image ghosting and transitional flicker increase when transitioning from low OPR to high OPR images
Solution Approach 1:
The system employs periodic high scan rate updates at specific transition moments (when switching from low OPR to high OPR images) rather than maintaining a continuously high scan rate. This periodic intervention briefly activates the high scan rate capability to clear ghosting artifacts, then returns to the power-efficient low scan rate mode, thus resolving the contradiction between power consumption and image quality
Solution Approach 2:
The system dynamically changes the scan rate parameter based on the OPR characteristics of the displayed image. When a high OPR image is detected, the scan rate is temporarily increased from the low power-saving rate to a high refresh rate to mitigate ghosting. This parameter adaptation allows the system to maintain power efficiency during normal operation while ensuring image quality during transitions
2Reliability
If the central control remains active to mitigate ghosting, then image quality is maintained, but power consumption increases
Solution Approach 1:
The AOD panel is equipped with autonomous capability to detect OPR changes and self-regulate its scan rate without continuous central control intervention. The panel can independently switch between low and high scan rates based on the displayed image characteristics, allowing the central control to enter sleep mode while maintaining image quality through the panel's self-managed periodic high scan rate updates
3Adaptability or versatility
If the AOD panel transitions from low OPR to high OPR images, then display functionality is enhanced, but image ghosting and transitional flicker occur
Solution Approach 1:
The system performs preliminary detection of OPR changes before the actual image transition becomes problematic. When a transition from low OPR to high OPR is detected, the system proactively activates high scan rate updates in advance to prevent ghosting artifacts from forming, thus maintaining image quality while preserving display versatility
Data Source
AI summary
This document describes a technology for reducing image ghosting on Always-On Display (AOD) panels when displaying high On-Pixel Ratio (OPR) images. The disclosed technology utilizes a multi-scan rate-capable AOD display panel to address the ghosting effect when the panel transitions from displaying a low OPR image to a high OPR image. To mitigate image ghosting and/or transitional flicker, the system briefly displays the high OPR image at a high scan rate before switching to a lower scan rate. This approach helps reduce ghosting and flicker helping to ensure power efficiency.