TFT Substrate Common Voltage Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In liquid crystal display (LCD) devices, the non-uniform application of common voltage to the thin film transistor (TFT) substrate due to self-resistance in the common voltage line leads to picture quality issues such as residual images and flickers.
Innovation Solution
The TFT substrate design includes a plurality of gate and data wirings, common voltage lines, and common electrodes that overlap and connect in specific patterns to ensure uniform common voltage distribution across the substrate, with dummy pixels receiving the same common voltage as display pixels to maintain a uniform cell gap and reduce voltage resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single common voltage line is used to apply common voltage to the common electrode, then the device structure is simple, but the common voltage is not uniformly applied due to self-resistance causing voltage drop
Solution Approach 1:
The single common voltage line is divided into multiple segments (first common voltage line and second common voltage line) that are spatially separated and distributed across different regions of the substrate. This segmentation reduces the current load on each individual line, minimizing self-resistance effects and voltage drop, thereby achieving more uniform common voltage distribution across the common electrode.
Solution Approach 2:
The patent transitions from a single-dimensional common voltage line arrangement to a two-dimensional network of multiple common voltage lines distributed across the substrate. This dimensional expansion allows voltage to be applied from multiple locations simultaneously, reducing the effective path length and resistance for voltage distribution, thus improving voltage uniformity.
2Device complexity
If dummy pixels are not provided at the non-display area, then the device structure is simpler, but the cell gap becomes non-uniform when substrates are attached
Solution Approach 1:
Dummy pixels are strategically placed in the non-display area where they are needed to maintain cell gap uniformity, while the display area maintains its functional pixel structure. This local application of dummy pixels solves the cell gap problem at the edges without interfering with the display functionality of the main pixel array.
Solution Approach 2:
The dummy pixels serve multiple functions: they maintain cell gap uniformity at the substrate edges, provide structural support for substrate attachment, and ensure proper alignment between the TFT substrate and color filter substrate. This multi-functionality allows a single structural element to address multiple manufacturing requirements.
3Quantity of substance
If the common voltage line has high self-resistance, then the wiring can be thinner and use less material, but the voltage drop increases causing non-uniform common voltage application
Solution Approach 1:
The common voltage line is segmented into multiple shorter sections distributed across the substrate. Each segment carries less current over a shorter distance, reducing the voltage drop in each segment. The parallel arrangement of multiple segments effectively reduces the total resistance compared to a single long line, allowing for optimized material usage while maintaining voltage uniformity.
Solution Approach 2:
The patent distributes common voltage lines across the two-dimensional substrate area rather than using a single centralized line. This spatial distribution creates multiple parallel current paths, reducing the effective resistance and voltage drop while allowing for thinner wiring that uses less material.
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 design stabilizes the application of common voltage, minimizing flickers and residual images by ensuring consistent voltage distribution across the TFT substrate, thereby enhancing picture quality.
Implementation Method 1
a plurality of common voltage lines formed along edges of pixels and mutually connected in an extending direction of the gate wirings; and a plurality of common electrodes formed at the pixel such that the plurality of common electrodes partially overlap with the common voltage line
Data Source
AI summary
A thin film transistor (TFT) substrate includes: a plurality of gate wirings; a plurality of data wirings insulatedly crossing the gate wirings to define a plurality of pixels; a plurality of common voltage lines formed along edges of pixels and mutually connected in an extending direction of the gate wirings; and a plurality of common electrodes formed at the pixel such that the plurality of common electrodes partially overlap with the common voltage line and mutually connected in an extending direction of the data wirings. A uniform common voltage can be stably applied on the entire surface of the TFT substrate.