OLED Display Timing Control with Variable Stress Periods for Flicker Reduction
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Solution Overview
Problem
OLED display devices experience deterioration and flicker due to luminance deviation between refresh and holding subframes when driven at low frequencies, degrading display quality.
Innovation Solution
A display device with a timing controlling circuit that adjusts the stress period width during the holding subframe based on luminance bands, using data and gate control signals to generate stress and emission signals, thereby reducing flicker and improving display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the OLED display device is driven with a relatively low frequency such as about 1 Hz, then power consumption is reduced and the device can maintain image display during standby mode, but deterioration such as flicker occurs due to luminance deviation between refresh subframe and holding subframe, degrading display quality
Solution Approach 1:
The patent applies dynamics by making the stress period width variable rather than fixed. The timing controlling circuit dynamically adjusts the width of the stress period in the holding subframe based on the luminance band of the image being displayed. This dynamic adjustment allows the system to optimize the balance between power consumption and display quality under different operating conditions, resolving the contradiction between low power consumption and maintaining high display quality.
Solution Approach 2:
The patent changes the parameter of stress period width according to luminance bands. By categorizing images into different luminance bands and adjusting the stress period width accordingly, the system optimizes the holding subframe performance for different display conditions. This parameter change enables the device to maintain display quality while operating at low frequency, thereby reducing power consumption without sacrificing reliability.
2Reliability
If the width of the stress period is increased during the holding subframe, then the luminance deviation between refresh and holding subframes is reduced, but the refresh-holding gap is enlarged, potentially affecting response time
Solution Approach 1:
The patent applies local quality by differentiating the stress period width based on local characteristics of the image, specifically the luminance band. Different regions or types of images (high luminance, low luminance, mid luminance) receive different stress period widths optimized for their specific requirements. This localized optimization reduces luminance deviation without unnecessarily increasing the refresh-holding gap for all cases, thus balancing luminance uniformity with response time.
Solution Approach 2:
The system dynamically adjusts the stress period width based on real-time detection of luminance bands, making the timing adjustment adaptive rather than static. This dynamic approach allows the system to minimize the refresh-holding gap when possible while extending it when needed for luminance uniformity, optimizing both parameters simultaneously.
3Reliability
If the stress period width is adjusted according to luminance band, then flicker is reduced and display quality is improved, but the device complexity increases due to additional timing control requirements
Solution Approach 1:
The timing controlling circuit is designed to perform multiple functions: it generates timing signals for the refresh subframe, detects luminance bands of the image, determines appropriate stress period widths, and controls the holding subframe timing. By making this single circuit multi-functional, the patent reduces the need for separate dedicated circuits for each function, thereby limiting the increase in device complexity while still achieving improved display quality through luminance-based stress period adjustment.
Data Source
AI summary
A display device includes: a timing controlling circuit configured to generate an image data, a data control signal and a gate control signal; a data driving circuit configured to generate a data signal, a stress signal and an anode reset signal using the image data and the data control signal; a gate driving circuit configured to generate a gate1 signal, a gate2 signal, an emission1 signal and an emission2 signal using the gate control signal; and a display panel configured to display an image using the data signal, the gate1 signal, the gate2 signal, the emission1 signal and the emission2 signal, wherein a width of a stress period between a rising timing of the gate2 signal and a rising timing of the emission1 signal is changed according to a luminance band of the image.