Liquid Crystal Display Reflective Electrode Corrosion Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display devices with reflective electrodes made of aluminum or silver and copper wiring lines face issues such as flicker, electrolytic corrosion, and increased complexity in manufacturing, leading to reduced display quality and reliability.
Innovation Solution
A liquid crystal display device structure where the reflective electrode is formed with a metal layer of aluminum or silver, and copper is used only for the gate and source wiring lines as an uppermost layer, with a transparent conductive pixel electrode positioned above the reflective electrode, and a terminal portion without a conductive layer matching the reflective electrode, along with organic insulating layers to prevent contact and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reflective electrode made of aluminum or silver and a copper wiring line are used together, then low resistance and good reflectivity are achieved, but flicker and electrolytic corrosion occur reducing display quality and reliability
Solution Approach 1:
An organic insulating layer is introduced as an intermediary between the copper wiring line and the aluminum or silver reflective electrode. This intermediate layer prevents direct contact between the two metals, thereby eliminating electrolytic corrosion and flicker while maintaining the electrical and optical performance of both materials.
Solution Approach 2:
The harmful interaction between copper wiring and aluminum/silver reflective electrode is extracted by removing the direct contact interface. The organic insulating layer is applied specifically at the interface where the two metals would otherwise contact, extracting the corrosion mechanism from the system while preserving the functional benefits of both materials.
2Reliability
If measures are taken to suppress flicker and corrosion (such as adding protective layers), then display quality and reliability are improved, but the manufacturing process and film composition become more complex
Solution Approach 1:
The organic insulating layer is applied locally only where needed - specifically at the interface between the copper wiring line and the aluminum or silver reflective electrode. This localized approach provides protection against corrosion and flicker without requiring complex multi-layer structures throughout the entire device, thereby maintaining manufacturing simplicity while achieving the desired reliability improvement.
Data Source
AI summary
A first substrate of a liquid crystal display device includes a plurality of gate wiring lines, a plurality of source wiring lines, a thin film transistor (TFT) provided in each of the pixels, a pixel electrode formed of a transparent conductive material and electrically connected to the TFT, a reflective electrode including a portion positioned in a reflective region, and a terminal portion disposed in a non-display region. The pixel electrode is formed in an upper layer above the reflective electrode, and the reflective electrode is not in contact with the pixel electrode. The terminal portion includes at least one of a first conductive layer formed in a same layer as that of the gate wiring lines and a second conductive layer formed in a same layer as that of the source wiring lines, and a third conductive layer formed in a same layer as that of the pixel electrode, and does not include a conductive layer formed in a same layer as that of the reflective electrode.