LCD Pixel Electrode Overlap for Image Sticking
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Solution Overview
Problem
In liquid crystal display devices, image sticking occurs due to differences in pixel capacitance among picture elements, causing variations in optimum counter voltages and leading to flicker or degradation of images, especially when the pixel electrode areas or liquid crystal layer thickness vary.
Innovation Solution
The solution involves adjusting the gate-drain capacitance and overlapping area of pixel electrodes with scanning lines to equalize the counter voltage among picture elements by making the gate-drain capacitance formed by pixel electrodes with larger pixel capacitance larger than those with smaller pixel capacitance, and varying the rate of increase in overlapping area along the scanning line signal direction, ensuring the counter voltage is closer to the optimum value for each element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pixel electrode areas or liquid crystal layer thickness are varied among sub-pixels, then color balance and luminance are improved, but pixel capacitance differences cause image sticking and flicker
Solution Approach 1:
The patent applies local quality by forming spacers at specific locations corresponding to sub-pixels with different capacitance values. Each spacer is positioned locally to compensate for capacitance differences in specific sub-pixels (e.g., white sub-pixels with larger area or different cell gap) without affecting other sub-pixels, thereby maintaining uniform counter voltage across all sub-pixels while preserving the benefits of varied pixel electrode areas for color balance and luminance.
Solution Approach 2:
The patent uses spacers as a counterbalancing mechanism to offset capacitance differences among sub-pixels. By strategically placing spacers in sub-pixels with larger capacitance (such as white sub-pixels with larger electrode areas or different cell gaps), the spacer capacitance acts as a counterweight to equalize the total capacitance across all sub-pixels, preventing image sticking and flicker while allowing luminance optimization through varied sub-pixel configurations.
2Quantity of substance
If pixel electrode area is increased to compensate for capacitance differences, then storage capacitance is improved, but the harmful effect of image sticking persists due to counter voltage variations
Solution Approach 1:
The patent applies local quality by forming spacers at specific locations corresponding to sub-pixels with different capacitance values. Each spacer is positioned locally to compensate for capacitance differences in specific sub-pixels (e.g., white sub-pixels with larger area or different cell gap) without affecting other sub-pixels, thereby maintaining uniform counter voltage across all sub-pixels while preserving the benefits of varied pixel electrode areas for color balance and luminance.
Solution Approach 2:
The patent uses spacers as a counterbalancing mechanism to offset capacitance differences among sub-pixels. By strategically placing spacers in sub-pixels with larger capacitance (such as white sub-pixels with larger electrode areas or different cell gaps), the spacer capacitance acts as a counterweight to equalize the total capacitance across all sub-pixels, preventing image sticking and flicker while allowing luminance optimization through varied sub-pixel configurations.
3Manufacturing precision
If multi-gap configuration is adopted to optimize sub-pixel performance, then display quality is improved, but pixel capacitance uniformity deteriorates
Solution Approach 1:
The patent applies local quality by forming spacers at specific locations corresponding to sub-pixels with different capacitance values. Each spacer is positioned locally to compensate for capacitance differences in specific sub-pixels (e.g., white sub-pixels with larger area or different cell gap) without affecting other sub-pixels, thereby maintaining uniform counter voltage across all sub-pixels while preserving the benefits of varied pixel electrode areas for color balance and luminance.
Solution Approach 2:
The patent employs parameter changes by varying the cell gap (thickness of liquid crystal layer) among different sub-pixels in a multi-gap configuration. White sub-pixels may have a different cell gap compared to RGB sub-pixels to optimize their optical performance. This parameter change allows optimization of display quality for each sub-pixel type while the spacer compensation mechanism maintains capacitance uniformity.
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 configuration effectively suppresses image sticking by maintaining uniform counter voltages across picture elements, improving image quality and reducing the likelihood of flicker or degradation.
Implementation Method 1
an alignment state of liquid crystal molecules is changed by applying a voltage to the liquid crystal layer by using a pair of electrodes formed on the substrates, and thereby a polarization state of the light passing through the liquid crystal layer is changed
Implementation Method 2
A liquid crystal display (LCD) device is a device which performs display in such a manner that the optical property of light emitted from a light source is controlled by using a liquid crystal layer
Data Source
AI summary
The present invention provides a liquid crystal display device which hardly causes image sticking in a panel in which Cgd gradation is performed, even when the pixel capacitances of the picture elements are different from one another. The liquid crystal display device of the present invention is a liquid crystal display device which includes a pair of substrates and a liquid crystal layer sandwiched between the pair of substrates, and is configured such that a pixel is formed by picture elements of a plurality of colors, wherein one of the pair of substrates includes scanning lines, signal lines, storage capacitor lines, thin film transistors connected to both of the scanning lines and the signal lines, and pixel electrodes connected to the thin film transistors; the other of the pair of substrates includes a counter electrode; the pixel electrodes are arranged for the picture elements; a scanning line and a pixel electrode form a gate-drain capacitance; the gate-drain capacitance formed by a pixel electrode with a larger pixel capacitance among the pixel electrodes arranged in one pixel is larger than the gate-drain capacitance formed by a pixel electrode with a smaller pixel capacitance among the pixel electrodes arranged in the one pixel; an overlapping area of each of the pixel electrodes overlapped with the scanning line initially increases in a travelling direction of a scanning line signal but a rate of the increase subsequently decreases, in each of the pixel electrodes respectively arranged for the picture elements of single colors; and rates of increase are different among the pixel electrodes with different pixel capacitances.