Panel Driver Compensation Frames for Variable Refresh Transitions
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Solution Overview
Problem
Existing display devices face challenges in maintaining image quality when operating in variable frequency modes, particularly in transitioning between different refresh rates, which can lead to issues such as flashing and reduced contrast ratio.
Innovation Solution
A display device with a panel driver that includes a comparator to adjust the refresh rate and insert compensation frames based on a difference value and reference percentage, using a determiner to set the final count of compensation frames, and a driving controller to manage data drivers and control the insertion of compensation frames to maintain image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the refresh rate is changed in variable frequency mode, then the display can adapt to different operating frequencies and improve power efficiency, but image quality deteriorates with flashing and reduced contrast ratio
Solution Approach 1:
The patent applies preliminary action by inserting compensation frames before the actual refresh rate transition completes. The driving controller calculates the difference between current and target refresh rates, then proactively inserts an appropriate number of compensation frames to preemptively correct potential image quality issues before they manifest, ensuring smooth transitions without flashing or contrast ratio degradation
2Reliability
If compensation frames are inserted to maintain image quality, then flashing is reduced and contrast ratio is improved, but the complexity of the driving controller increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the number of compensation frames based on the calculated difference value between current and target refresh rates. The driving controller uses a determination unit that references a lookup table or calculation logic to set the optimal compensation frame count, transforming a complex control problem into a parameter-based solution that maintains image quality without requiring overly complex hardware structures
3Reliability
If the number of compensation frames is increased, then image quality improves by reducing flashing, but the response time and power consumption increase
Solution Approach 1:
The patent applies partial action by inserting only the necessary number of compensation frames to achieve image quality improvement, rather than using a fixed large number. The driving controller calculates the minimal required compensation based on the refresh rate difference, inserting just enough frames to prevent flashing and maintain contrast ratio without unnecessarily extending response time or increasing power consumption
Data Source
AI summary
A display device includes: a display panel including a plurality of pixels; and a panel driver that drives the display panel at a target refresh rate different from a previous refresh rate. The panel driver includes: a comparator which compares a difference value between the previous refresh rate and the target refresh rate with a reference value generated by multiplying the previous refresh rate by a predetermined reference percentage; and a determiner which determines a final count of at least one compensation frame to be inserted between a previous driving frame operating at the previous refresh rate and a target driving frame operating at the target refresh rate when the difference value is not less than the reference value, where the final count is a total number of the at least one compensation frame, and a natural number.