VCOM Pre-compensation for Display Artifact Reduction
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Solution Overview
Problem
Electronic displays experience artifacts such as a greenish hue due to uncompensated VCOM voltage variations when coupled to datalines, particularly at high refresh rates or during simultaneous column or row driver switching.
Innovation Solution
The VCOM is pre-compensated by calculating and injecting charge to offset expected variations before coupling, using a next line buffer to determine pixel content for future pixels while writing to current pixels, thereby reducing or eliminating artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If VCOM is coupled to datalines for high refresh rate display, then display refresh rate is improved, but VCOM voltage stability deteriorates causing display artifacts
Solution Approach 1:
The patent applies preliminary action by pre-calculating the VCOM charge compensation value based on the current frame buffer content before the VCOM is coupled to the datalines. The compensation charge is injected in advance to offset expected voltage variations, ensuring VCOM stability is maintained even at high refresh rates where settling time is reduced.
2Speed
If high voltage slewing is applied to VCOM and dataline, then display response speed is improved, but VCOM settling time increases causing artifacts
Solution Approach 1:
The patent applies preliminary anti-action by injecting a compensation charge to the VCOM before coupling to the datalines. This pre-applied charge counteracts the voltage variations that would otherwise occur during high-speed voltage slewing, allowing fast response while maintaining adequate settling time and preventing display artifacts.
3Productivity
If column or row drivers switch simultaneously in the same direction, then display writing efficiency is improved, but VCOM settling time increases due to charge injection
Solution Approach 1:
The patent calculates the compensation charge based on the buffer content that reflects the upcoming driver switching patterns. By preparing the compensation charge in advance before simultaneous column or row driver switching occurs, the VCOM is pre-adjusted to accommodate the charge injection that will result from efficient simultaneous switching, thereby maintaining both writing efficiency and settling time.
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
This approach effectively reduces or eliminates display artifacts by stabilizing VCOM voltage levels before connection to datalines, improving display appearance and reducing settling times.
Implementation Method 1
The VCOM may then be injected with charge to offset the calculated variations that would result from the coupling
Data Source
AI summary
Methods and systems for compensating for VCOM variations include determining a voltage change in pixels between frames to be displayed on an electronic display. Based on the determined voltage change, VCOM variation is calculated based on coupling the VCOM to one or more data lines of the electronic display. VCOM compensation is determined and applied to offset for the VCOM variation. Using the VCOM offset, subsequent pixel content for the one or more pixels is written using the compensated VCOM.