Display Grayscale Compensation for IR Drop Across Data Lines
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Solution Overview
Problem
The phenomenon of voltage drops (IR drops) along data and source driver power lines in display panels due to impedance, leading to inconsistent grayscale rendering across sub-pixels and source drivers.
Innovation Solution
A display device incorporating a data conversion circuit, voltage drop estimation circuit, and compensation circuit to convert grayscale data into current data, estimate transmission line voltage drops, and compensate for these drops using pixel compensation values, utilizing panel factor parameters and interpolation/extrapolation for extended compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If data lines and source driver power lines are used to transmit signals and power across the display panel, then the display panel can be driven to show images, but voltage drops occur along these transmission lines due to impedance, causing inconsistent grayscale rendering across different sub-pixels and source drivers
Solution Approach 1:
The patent applies preliminary action by calculating and applying compensation values to the grayscale data before it is transmitted through the data lines. The compensation circuit pre-adjusts the grayscale values based on predicted voltage drops, so that after the voltage drop occurs during transmission, the final voltage at each sub-pixel achieves the desired grayscale level. This resolves the contradiction by addressing the energy loss in advance rather than attempting to maintain perfect voltage throughout transmission.
Solution Approach 2:
The patent changes the parameter of grayscale data values dynamically based on position and load conditions. Different compensation values are applied to different sub-pixels depending on their location in the panel and the current load on the data lines. This parameter adjustment compensates for the voltage drops that occur during transmission, ensuring consistent grayscale rendering across the entire panel despite the inherent energy loss in the transmission lines.
2Area of stationary object
If multiple source drivers are connected to the same source driver power line to drive large-sized display panels, then the power distribution can be extended across the panel, but different voltage drops occur at different positions of the power line, affecting source driver operation consistency
Solution Approach 1:
The patent applies local quality by providing different compensation values to different source drivers based on their specific locations and the local conditions of the power line. Each source driver receives customized compensation based on its position in the panel and the cumulative load it must drive. This localized approach to compensation ensures that each source driver can maintain consistent operation despite the varying voltage drops that occur along the extended power distribution network.
Solution Approach 2:
The patent implements feedback by using the calculated compensation values as a form of feedback mechanism. The system determines the actual or predicted voltage drop conditions and uses this information to adjust the grayscale data accordingly. This feedback loop ensures that the compensation applied is based on the actual transmission conditions, maintaining consistency across the large display panel area.
3Manufacturing precision
If voltage drop compensation is implemented through additional circuits (data conversion circuit, voltage drop estimation circuit, compensation circuit), then grayscale consistency can be improved, but the device complexity increases
Solution Approach 1:
The patent applies merging by integrating the data conversion, voltage drop estimation, and compensation functions into a unified compensation circuit architecture. Rather than implementing these as separate independent systems, the patent combines them into a coordinated circuit structure that processes grayscale data through a series of integrated stages. This merging reduces the overall complexity compared to having fully separate systems while still achieving the desired grayscale uniformity through the combined functionality.
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
Compensates for voltage drops on transmission lines, ensuring consistent grayscale rendering across sub-pixels and source drivers, improving display quality by dynamically calculating load and applying compensation values.
Implementation Method 1
Due to the impedance of the data lines, there may be the phenomenon of different voltage drops (also referred to as IR drops) at different positions of the data lines
Implementation Method 2
there may be the phenomenon of different voltage drops (also referred to as IR drops) at different positions of the data lines
Data Source
AI summary
The invention provides a display device and a grayscale compensation method thereof. The display device includes a data conversion circuit, a voltage drop estimation circuit, and a compensation circuit. The data conversion circuit converts a plurality of original grayscale data of a target pixel block into current data. The voltage drop estimation circuit converts the current data into transmission line voltage drop information of the target pixel block. The compensation circuit converts the transmission line voltage drop information into at least one pixel compensation value of the target pixel block and compensates the original grayscale data of the target pixel block using the at least one pixel compensation value to generate a plurality of compensated grayscale data of the target pixel block.