Display Panel Partial Driving for Afterimage Reduction
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Solution Overview
Problem
Display devices face issues with afterimages due to deviations in threshold voltages of pixel transistors when displaying black images on partial areas, causing luminance differences and visual artifacts.
Innovation Solution
A display device with a timing controller that operates in two modes: a normal mode for the entire display area and a partial driving mode for the black image area, where the black image area is driven at a lower frequency with active frames for writing a reference voltage and blank frames to maintain the bias voltage, reducing power consumption and minimizing luminance differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the display panel drives only a partial area to reduce power consumption, then power consumption is reduced, but threshold voltage deviations occur in pixel transistors causing afterimages
Solution Approach 1:
The display panel is divided into a first display area (active image area) and a second display area (black image area). The second area is further divided into multiple pixel rows that are selectively driven during blank frames. This segmentation allows different driving strategies for different regions, reducing overall power consumption while maintaining threshold voltage stability in the black image area through selective row-by-row refreshing.
Solution Approach 2:
The patent implements periodic action by dividing the driving cycle into active frames and blank frames. During blank frames, the second display area is periodically refreshed by applying bias voltages to pixel rows in a sequential manner. This periodic refreshing prevents threshold voltage deviations while consuming significantly less power than continuous full-panel driving.
2Use of energy by moving object
If a black image is displayed on a partial area to reduce power consumption, then power consumption is reduced, but luminance differences and afterimages occur
Solution Approach 1:
The patent applies local quality by implementing different driving methods for different areas. The first display area receives normal data signals for image display, while the second display area receives bias voltages during blank frames to maintain threshold voltage stability. This localized differential driving ensures luminance uniformity across the entire panel while reducing power consumption in the black image area.
Solution Approach 2:
The patent applies preliminary action by proactively applying bias voltages to pixel rows in the second display area during blank frames before threshold voltage deviations can occur. This preventive measure maintains threshold voltage stability and ensures luminance uniformity when the full panel is subsequently activated, avoiding afterimage artifacts.
3Use of energy by moving object
If the driving frequency is reduced in the black image area, then power consumption is reduced, but threshold voltage deviations occur more easily
Solution Approach 1:
The patent implements periodic action by alternating between active frames (for image display) and blank frames (for threshold voltage maintenance). During blank frames, pixel rows in the second display area are sequentially refreshed with bias voltages at a reduced frequency. This periodic refreshing maintains threshold voltage stability while significantly reducing power consumption compared to continuous full-frequency driving.
Solution Approach 2:
The patent applies preliminary action by proactively refreshing pixel rows with bias voltages during blank frames before threshold voltage deviations can develop. This preventive refreshing occurs at a reduced frequency in the black image area, maintaining reliability while reducing power consumption.
Data Source
AI summary
A display device includes a display panel having first and second display areas. A data driver provides data and bias voltages to data lines. A timing controller controls the data driver and a scan driver based on at least two operation modes. The first mode drives the first and second display areas at a normal frequency, and the second mode drives the first display area at a first frequency substantially equal to or lower than the normal frequency and the second display area at a second frequency lower than the first frequency. The second mode includes an active frame to write a reference voltage to display a black image in the second display area, and blank frames to maintain the reference voltage and apply the bias voltage to the pixels in the second display area. The data driver varies the bias voltage in the blank frames.