Display Pixel Bias Adjustment for Frequency-Shift Flicker
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Solution Overview
Problem
Display apparatuses experience luminance differences and flicker when the driving frequency changes from high to low, due to differing hysteresis characteristics in the writing and holding periods, which affect display quality.
Innovation Solution
Adjust the level of the bias voltage according to the light emission time when the driving frequency changes, specifically increasing the bias voltage during longer light emission times to reduce luminance differences and flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the driving frequency of the display panel is changed from high to low, then the light emission time of the pixel is increased, but a luminance difference is generated due to hysteresis characteristics of the driving transistor
Solution Approach 1:
The patent applies parameter changes by adjusting the bias voltage level applied to the driving transistor based on the light emission time duration. When the light emission time is extended (low frequency driving), a higher bias voltage is applied to compensate for the hysteresis effect, thereby maintaining consistent luminance output across different driving frequencies
Solution Approach 2:
The patent implements preliminary action by pre-adjusting the bias voltage level before the pixel operates at low frequency. The driving controller detects the extended light emission time and proactively increases the bias voltage to prevent luminance degradation caused by hysteresis, rather than correcting it after the fact
2Duration of action of moving object
If the driving frequency is reduced to increase light emission time, then display quality should be improved, but flicker becomes perceivable due to luminance difference
Solution Approach 1:
The patent changes the bias voltage parameter dynamically based on driving frequency and light emission time. By increasing the bias voltage during extended light emission periods, the hysteresis-induced luminance variations that cause flicker are compensated, allowing low frequency driving without perceivable flicker
Solution Approach 2:
The driving controller implements feedback by monitoring the driving frequency and light emission time duration, then adjusting the bias voltage level accordingly. This closed-loop control ensures that the bias voltage is optimized for each operating condition, preventing flicker while maintaining display quality
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces luminance differences and flicker, enhancing display quality by compensating for luminance decreases in high grayscale ranges and maintaining consistent luminance across frequency changes.
Implementation Method 1
The pixel includes a light emitting element
Data Source
AI summary
A display apparatus includes a display panel, a gate driver, a data driver and an emission driver. The display panel includes a pixel. The gate driver is configured to output a gate signal to the pixel. The data driver is configured to output a data voltage to the pixel. The emission driver is configured to output an emission signal to the pixel. The pixel includes a light emitting element, a driving switching element configured to apply a driving current to the light emitting element and a bias switching element configured to apply a bias voltage to the driving switching element. The display apparatus increases a level of the bias voltage when a duration of a light emission time of the pixel is increased.