Transparent Conducting Layer LCD Panel Aperture Ratio
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Solution Overview
Problem
Current liquid crystal display (LCD) panels face challenges in raising the frame rate while maintaining aperture ratio and display brightness, as the maximum effective charging time is insufficient for higher frame rates due to RC delay and charging performance limitations of thin film transistors (TFTs).
Innovation Solution
A new LCD panel structure is developed where a transparent conducting layer forms first and second electrodes directly connected to the data line and thin film transistor, eliminating the need for via holes over the TFT, allowing for increased aperture ratio and transmittance by extending the area of the pixel electrode and optimizing the TFT structure with a five-mask process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If via holes are formed over the TFT to connect the data line to the pixel electrode, then electrical connection is achieved, but the aperture ratio and transmittance are reduced
Solution Approach 1:
The patent extracts and eliminates the via hole structure from the conventional design. Instead of forming via holes through the passivation layer and TFT to connect the data line to the pixel electrode, the invention uses a transparent conducting layer that directly contacts the data line and extends to form the pixel electrode, completely removing the need for via holes and thereby maximizing the aperture ratio
Solution Approach 2:
The patent merges the functions of the transparent conducting layer and the pixel electrode into a single integrated structure. The transparent conducting layer serves dual purposes: as the pixel electrode for liquid crystal control and as the connecting conductor to the data line, eliminating the need for separate via hole connections and reducing structural complexity
2Productivity
If the frame rate is increased to improve display quality, then the charging time period decreases, but the RC delay and TFT charging performance become insufficient
Solution Approach 1:
The patent changes the electrical parameters of the connection structure by eliminating via holes and using a direct transparent conducting layer connection. This reduces the overall resistance and capacitance in the charging path, thereby reducing RC delay and enabling faster charging that supports higher frame rates
Solution Approach 2:
The patent transitions from a vertical via-hole connection approach to a planar extended connection approach. The transparent conducting layer extends from the data line across the pixel area to form the pixel electrode, creating a larger effective charging area and improving charging efficiency without increasing the charging path length
Data Source
AI summary
The present invention discloses a liquid crystal display (LCD) panel and method for forming the same. In the LCD panel, the TFT includes a source and a drain formed by a transparent conducting layer, and a gate formed by a metal layer. The source is electrically connected with a data line through a via hole over the data line. The source connects to the drain via an active layer. Whatever the number of data lines are, each pixel corresponds to an associated via hole, so the number of via holes does not increase, and not reduce the aperture ratio. Therefore, the present invention is very proper to a design using more data lines and working in a high frequency. Moreover, the matrix circuitry of LCD of the present invention is well applied in a display which not only increases a density of data lines to raise the frame rate, but also maintains the aperture ratio and brightness.