Pixel Array Substrate With Position-Dependent Storage Capacitance
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Solution Overview
Problem
In liquid crystal display (LCD) devices, the feed-through voltage effect causes variations in pixel electrode voltages along a scan line, leading to flickering and reduced display quality due to increased resistance and capacitance with distance from the scan line input end, which cannot be fully eliminated by adjusting the common electrode voltage.
Innovation Solution
The capacitances of pixel storage capacitors are varied along a scan line by adjusting the overlap areas between capacitor electrodes and the first patterned conductor layer, ensuring that all pixels experience a consistent feed-through voltage, thereby maintaining identical voltage differences and reducing flickering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the scan line length is increased to accommodate more pixels, then the display area is improved, but the resistance and capacitance of the scan line increase causing greater voltage drop and feed-through voltage variations
Solution Approach 1:
The patent applies local quality by making the storage capacitor characteristics position-dependent along the scan line. Pixels closer to the scan line input end have smaller storage capacitors, while pixels farther away have larger storage capacitors. This local variation in capacitor size compensates for the cumulative resistance and capacitance effects of the scan line, maintaining uniform feed-through voltage across the entire display area without requiring uniform capacitor designs.
2Reliability
If the common electrode voltage is adjusted to eliminate feed-through voltage impact, then the display quality is improved, but the voltage drop along the scan line increases causing non-uniform feed-through voltage across different pixels
Solution Approach 1:
The patent changes the capacitance parameter of the storage capacitors based on their position along the scan line. By varying the capacitor size (a key electrical parameter) according to location, the system compensates for the voltage drop effects without needing to adjust the common electrode voltage. This parameter variation approach allows each pixel to have optimized feed-through voltage characteristics despite the non-uniform scan line conditions.
3Ease of manufacture
If the storage capacitor size is made uniform across all pixels, then the manufacturing complexity is reduced, but the feed-through voltage varies along the scan line causing flickering
Solution Approach 1:
The patent implements local quality by designing storage capacitors with position-dependent sizes. Instead of using uniform capacitors throughout the display, each pixel's storage capacitor is specifically sized according to its distance from the scan line input end. This local customization eliminates flickering caused by feed-through voltage variations while remaining manufacturable through systematic design rules that can be applied during the fabrication process.
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 ensures that all pixels in an LCD display have a consistent feed-through voltage effect, improving image quality by eliminating flickering and maintaining uniformity in display performance without altering pixel apertures or increasing costs significantly.
Implementation Method 1
the voltage level of the pixel electrodes in each of the pixels P10A, P10B, P10C, and so forth, are maintained by a respective liquid crystal capacitor and the pixel storage capacitor
Implementation Method 2
the voltage level of the pixel electrodes in each of the pixels P10A, P10B, P10C, and so forth, are maintained by a respective liquid crystal capacitor and the pixel storage capacitor
Implementation Method 3
The voltage change of a pixel electrode due to coupling effect is referred to as feed-through voltage (VFD). The feed-through voltage can generally be expressed as: VFD=[CGD/(CLC+CST+CGD)]×ΔVG
Data Source
AI summary
A display device has a pixel array substrate that contains a support substrate and a plurality of pixel areas arranged on the support substrate. Each pixel area contains a pixel electrode and a capacitor electrode. Scan lines and common lines are also provided, where each common line has portions provided in respective pixel areas. Each pixel area has a storage capacitance defined by an overlapping area between a respective capacitor electrode and a respective one of a scan line and common line, where the storage capacitances of pixel areas along each scan line varies along the scan line.