Display Device Vertical Blank Region Leakage Compensation
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Solution Overview
Problem
Current display technologies with Freesync functions face issues of excessive grayscale brightness changes due to longer hold times of pixel capacitor voltage during vertical blank periods at low refresh frequencies, leading to leakage and failure in certification processes.
Innovation Solution
A display method that calculates the current frame display period based on the GPU's refresh frequency, determines the start and lasting duration of the vertical blank region, and controls the target image to be displayed from the start time according to the lasting duration, thereby preventing excessive grayscale brightness changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the refresh frequency is reduced to maintain grayscale brightness during vertical blank period, then the hold time of pixel capacitor voltage becomes longer, but this causes more leakage and greater difference in grayscale brightness
Solution Approach 1:
The patent applies preliminary action by inserting a compensation image during the vertical blank period before the actual display content begins. This compensation image pre-adjusts the pixel capacitor voltage to account for expected leakage, ensuring that when the actual content displays, the grayscale brightness remains consistent despite the longer hold time at low refresh frequencies.
Solution Approach 2:
The patent changes parameters by dynamically adjusting the compensation image's grayscale value based on the actual refresh frequency. When refresh frequency drops below the preset frequency, the system calculates the duration of the vertical blank period and sets the compensation image's brightness parameter accordingly, creating a frequency-dependent compensation mechanism that optimizes grayscale consistency across varying refresh rates.
2Adaptability or versatility
If the vertical blank period is extended to accommodate lower refresh frequencies, then the display can support variable refresh rates, but the grayscale brightness consistency deteriorates due to increased leakage
Solution Approach 1:
The system performs preliminary compensation by displaying a compensation image during the vertical blank period, proactively addressing the leakage issue before it affects the actual display content. This allows the display to maintain grayscale consistency across variable refresh frequencies without compromising brightness stability.
Solution Approach 2:
The patent implements a feedback mechanism by continuously monitoring the actual refresh frequency and dynamically adjusting the compensation image parameters accordingly. When the refresh frequency deviates from the preset frequency, the system calculates the appropriate compensation based on the actual vertical blank period duration, creating a closed-loop control system that maintains grayscale consistency across varying refresh rates.
3Duration of action of stationary object
If the hold time of pixel capacitor voltage is increased to maintain brightness at low refresh frequencies, then the display can operate at lower refresh rates, but leakage increases causing grayscale voltage changes
Solution Approach 1:
The system applies preliminary compensation by inserting a compensation image during the vertical blank period that proactively counteracts the expected voltage leakage. This compensation occurs before the actual display content, ensuring that even with extended hold times at low refresh frequencies, the grayscale voltage remains stable when the actual content is displayed.
Data Source
AI summary
A display method, a display device, and a display apparatus are provided. The display method includes following steps: obtaining a current frame display period corresponding to a current refresh frequency of a GPU, wherein the current frame display period is a sum of a duration of a frame display and a duration of a vertical blank region; determining a start time and a lasting duration of the vertical blank region based on a preset frame display duration and the current frame display period; and controlling a target image to be displayed from the start time according to the lasting duration.