Display Timing Controller Sub-Frame Insertion for Luminance Stability
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Solution Overview
Problem
Display devices face degradation in luminance due to varying frame rates, leading to reduced image quality and potential flicker perception as charges in pixels leak during extended blank periods.
Innovation Solution
A display apparatus that includes a timing controller which detects the frame period corresponding to the input image's frame rate and compares it to a critical period, inserting a sub frame duration for image refresh when the frame period is longer than the critical period to maintain charge levels and prevent luminance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the frame rate of the input image is reduced to save power or handle lower-speed content, then power consumption decreases and processing load reduces, but the luminance of the displayed image degrades and flicker becomes perceptible
Solution Approach 1:
The frame period is segmented into multiple sub-frame periods, with active data periods and blank periods divided accordingly. By inserting sub-frame durations within the overall frame period, the patent maintains adequate refresh frequency for luminance stability while allowing the overall frame rate to be reduced for power savings.
Solution Approach 2:
The patent implements periodic active data output within each sub-frame duration to refresh pixel charges regularly. This periodic refresh action ensures that even at reduced overall frame rates, the luminance remains stable by preventing charge leakage during extended blank periods.
2Loss of time
If the frame period is extended to display lower frame rates, then power consumption reduces and processing load decreases, but charge leakage in pixels increases causing luminance degradation
Solution Approach 1:
The extended frame period is segmented into multiple sub-frame durations, each containing active data periods followed by blank periods. This segmentation ensures that no single blank period exceeds the critical duration that would cause significant charge leakage, thereby maintaining charge retention reliability even when the overall frame period is extended.
Solution Approach 2:
Active data is output in multiple sub-frame durations before the end of the overall frame period. This preliminary action of refreshing pixel charges in advance prevents charge leakage from causing luminance degradation, ensuring reliable charge retention throughout the extended frame period.
3Illumination intensity
If active data is output continuously at high frame rates, then luminance stability is maintained and flicker is suppressed, but power consumption increases and processing complexity increases
Solution Approach 1:
The patent dynamically adjusts the sub-frame duration and the number of sub-frames within each frame period based on the detected frame rate. When input frame rate is low, it inserts more sub-frames with appropriate active data periods to maintain luminance stability. When input frame rate is high, it reduces or eliminates sub-frame insertion, thereby reducing power consumption while maintaining image quality.
Solution Approach 2:
The timing controller changes parameters such as sub-frame duration, number of sub-frames, and active data period distribution based on the detected input frame rate. This adaptive parameter adjustment optimizes the balance between luminance stability and power consumption for different operating conditions.
4Illumination intensity
If sub-frame duration is inserted to maintain luminance at low frame rates, then luminance degradation is suppressed and image quality is maintained, but device complexity increases
Solution Approach 1:
The timing controller automatically detects the input frame rate and autonomously determines the appropriate sub-frame insertion strategy. This self-service mechanism eliminates the need for external intervention or complex manual configuration, reducing operational complexity while maintaining luminance stability through adaptive sub-frame management.
Solution Approach 2:
The timing controller continuously monitors the input frame rate and uses this feedback to adjust the sub-frame duration and insertion timing. This closed-loop feedback mechanism ensures optimal luminance maintenance while simplifying control logic, as the system automatically adapts to changing frame rates without requiring complex predetermined configurations.
Data Source
AI summary
A display apparatus includes a display panel including a plurality of pixels; a timing controller generating image data, a data control signal, and a gate control signal, based on an input image signal and an input control signal; a data driver generating a data signal for an output image based on the image data and the data control signal and supplying the data signal to the pixels; a gate driver generating a gate signal based on the gate control signal and supplying the gate signal for the output image to the pixels. The timing controller detects a frame period corresponding to a frame rate of the input image and when the detected frame period is longer than the critical period, inserts a sub frame duration to output active data for image refresh after outputting active data of an output frame duration corresponding to the output image.