LCD Sub-pixel Voltage Compensation for Frame Flash
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Solution Overview
Problem
Conventional LCDs experience frame flash due to differences in feed-through voltages between sub-pixels of varying areas or shapes, leading to asymmetrical luminance when polarity inverts, even when adjusting data voltages for the same grey value.
Innovation Solution
The solution involves setting different positive and negative data voltages for sub-pixels based on their individual feed-through voltages, ensuring that the average voltage of each sub-pixel is symmetrical with respect to a common voltage, thereby eliminating frame flash by compensating for the unique capacitance characteristics of each sub-pixel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If sub-pixels with different areas or shapes receive the same data voltage, then the display unit can maintain simple voltage control, but the feed-through voltages become different causing frame flash and luminance inconsistency
Solution Approach 1:
The patent applies local quality by assigning different data voltages to different sub-pixels based on their specific capacitance characteristics. Each sub-pixel receives a customized data voltage that compensates for its unique area and shape, ensuring uniform luminance output across the display while maintaining simple voltage control architecture.
Solution Approach 2:
The patent changes the data voltage parameter for each sub-pixel based on its feed-through voltage characteristics. By calculating and applying sub-pixel-specific data voltages that compensate for capacitance differences, the system eliminates frame flash and ensures consistent luminance while keeping the overall voltage control approach simple.
2Manufacturing precision
If different data voltages are applied to compensate for feed-through effects, then luminance consistency is improved, but the complexity of voltage control increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the compensation values for each sub-pixel's feed-through voltage before the display operates. This allows the system to maintain luminance consistency through simple voltage lookups during operation, avoiding complex real-time calculations and reducing operational complexity.
Solution Approach 2:
The patent uses feedback mechanisms where the system measures or pre-determines the feed-through voltage characteristics of each sub-pixel and uses this information to adjust the data voltages accordingly. This feedback approach ensures luminance consistency while maintaining simple control through automated compensation rather than manual adjustment.
3Device complexity
If the same data voltage is used for all sub-pixels, then the driving circuit is simple, but sub-pixels with different areas or shapes generate different feed-through voltages causing frame flash
Solution Approach 1:
The patent addresses frame flash by applying local quality through sub-pixel-specific voltage compensation. Each sub-pixel receives a customized data voltage that accounts for its unique area and shape, eliminating the feed-through voltage differences that cause frame flash while keeping the overall driving circuit architecture simple and unified.
Solution Approach 2:
The patent eliminates frame flash by changing the data voltage parameter for each sub-pixel based on its capacitance characteristics. This parameter adjustment compensates for feed-through effects without requiring complex circuit modifications, maintaining driving circuit simplicity while preventing frame flash through software-based voltage compensation.
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 resolves the frame flash issue by ensuring that sub-pixels with different areas or shapes display consistent luminance for the same grey value, improving image quality by maintaining symmetry in pixel voltages during polarity inversion.
Implementation Method 1
the capacitance of the liquid crystal capacitor of a sub-pixel is related to the data voltage received and the area and shape of the sub-pixel
Implementation Method 2
for the sake of capacitor coupling of the transistor switch T1, the voltage of the pixel electrode of the sub-pixel A is shifted down due to a feed-through effect
Implementation Method 3
a liquid crystal display (LCD) and driving method thereof
Data Source
AI summary
A LCD includes at least a first sub-pixel and a second sub-pixel with different area. Each sub-pixel displays luminance according to a positive or a negative data voltage corresponding to a grey value. When the grey values of the first sub-pixel and the second sub-pixel are equal, an average value of the positive and negative data voltages of the first sub-pixel is not equal to an average value of the positive and negative data voltages of the second sub-pixel.