LCD Sub-Pixel Voltage Control for Color Shift Reduction
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Solution Overview
Problem
Conventional liquid crystal display panels experience color shift due to uniform voltage distribution across sub-pixel areas, leading to inconsistent brightness.
Innovation Solution
The implementation of a pixel structure with a first and second sub-pixel area, each with its own electrode connected to capacitors, where a circuit element allows charge transfer between these capacitors when a gate-line signal passes, creating a voltage difference between the sub-pixel areas, thereby adjusting the liquid crystal molecule alignment and reducing color shift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform voltage distribution is applied across sub-pixel areas, then manufacturing and circuit design are simplified, but color shift occurs due to inconsistent brightness
Solution Approach 1:
The patent applies local quality by providing different voltage levels to different sub-pixel areas within the same pixel. Specifically, the first sub-pixel area receives a first voltage level while the second sub-pixel area receives a second voltage level, allowing each area to be optimized for its specific function (transmissive vs. reflective) rather than applying uniform voltage across all areas.
Solution Approach 2:
The patent segments the pixel into distinct sub-pixel areas with independent voltage control. Each sub-pixel area has its own electrode and capacitor configuration, enabling separate voltage management. This segmentation allows the transmissive and reflective portions to operate at optimally different voltage levels, preventing color shift while maintaining manufacturing feasibility through modular circuit design.
2Object-affected harmful factors
If different voltage levels are applied to sub-pixel areas, then color shift is reduced, but device complexity increases
Solution Approach 1:
The patent merges the voltage control functions by using the same gate-line signal to control switching elements in both sub-pixel areas. The gate-line signal simultaneously controls the first switching element and the second switching element, coordinating the voltage application to different sub-pixel areas without requiring separate control circuits, thus reducing overall device complexity.
Solution Approach 2:
The patent implements multi-functionality by designing capacitors that serve dual purposes: during the on-period, they maintain voltage levels for liquid crystal alignment; during the off-period, they enable charge transfer between sub-pixel areas through the third switching element. This universal capacitor design reduces the need for separate voltage management circuits.
3Adaptability or versatility
If charge transfer between capacitors is implemented, then voltage level adjustment is achieved, but additional circuit elements are required
Solution Approach 1:
The patent implements dynamic voltage control by enabling charge transfer between capacitors based on the gate-line signal timing. The third switching element is controlled to transfer charge from the second capacitor to the third capacitor during specific time periods, allowing the voltage levels to be dynamically adjusted according to display requirements rather than being fixed.
Solution Approach 2:
The patent applies self-service by using the existing gate-line signal to control the charge transfer process. The same gate-line signal that controls the primary switching elements also controls the third switching element, allowing the circuit to self-regulate voltage levels without requiring external control signals or additional complex control logic.
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 results in a slight brightness difference between sub-pixel areas, effectively reducing color shift and enhancing display properties by allowing for controlled voltage level adjustments.
Implementation Method 1
a circuit element causes the capacitor associated with the second sub-pixel electrode to transfer its charge to another capacitor, resulting in a reduction of the voltage level on the second sub-pixel electrode
Implementation Method 2
the alignment of the liquid crystal molecules in the first sub-pixel area is slightly different from the alignment of the liquid crystal molecules in the second sub-pixel area, resulting in a slight brightness difference between the first and the second sub-pixel areas
Data Source
Figure 1
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Figure 4
AI summary
A pixel in a liquid crystal display panel comprises a first sub-pixel area having a first sub-pixel electrode and a second sub-pixel area having a second sub-pixel electrode. Each sub-pixel electrode is associated with a capacitor. When a gate-line signal and a data voltage is provided to the pixel, the voltage level on the first sub-pixel electrode is substantially equal to or slightly higher than the voltage level on the second sub-pixel electrode and the capacitor associated with each sub-pixel electrode is charged. When the gate-line signal has entirely passed on partially passed, a circuit element causes the capacitor associated with the second sub-pixel electrode to transfer its charge to another capacitor, resulting in a reduction of the voltage level on the second sub-pixel electrode.