LCD Pad Electrode Side Contact for Low Resistance
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Solution Overview
Problem
The existing liquid crystal display (LCD) devices face issues with increased contact resistance due to small contact areas between pad electrodes and terminals, leading to signal delays and degraded display quality.
Innovation Solution
The LCD device incorporates pad electrodes with unevenly shaped contact holes and terminals that contact the inner surfaces of the pad electrodes, increasing the contact area and reducing resistance, achieved through specific manufacturing processes involving multiple mask steps and conductive materials like molybdenum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a rectangular pad contact hole is used in the data pad region, then the manufacturing process is simple, but the contact area between pad electrode and terminal is small, causing increased contact resistance
Solution Approach 1:
The invention transitions from a conventional top-down contact approach to a side-contact approach by forming the pad contact hole to expose inner side surfaces of the pad electrode. The terminal then contacts these side surfaces, effectively utilizing the vertical dimension to increase contact area without complicating the horizontal layout.
Solution Approach 2:
The contact interface is segmented into multiple contact points around the pad contact hole perimeter. Instead of a single centralized contact, the terminal makes contact at multiple locations along the inner side surfaces, distributing the electrical connection and increasing total contact area.
2Reliability
If the contact area between pad electrode and terminal is increased, then contact resistance is reduced, but the device structure becomes more complex
Solution Approach 1:
The invention utilizes the vertical dimension by forming the pad contact hole to expose inner side surfaces, allowing the terminal to contact these side surfaces. This dimensional transition increases contact area without requiring additional horizontal space or complex multi-layer structures.
Solution Approach 2:
The pad electrode structure itself provides the contact surface through its inner side surfaces exposed by the pad contact hole. The existing pad electrode geometry is utilized to create the contact interface, eliminating the need for separate contact structures or additional manufacturing steps.
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 reduces contact resistance, minimizing signal delays and enhancing display quality by increasing the contact area between pad electrodes and terminals.
Implementation Method 1
a voltage applied between the electrodes induces an electric field across the liquid crystal material. Alignment of the liquid crystal molecules in the liquid crystal material changes in accordance with the intensity of the induced electric field into the direction of the induced electric field, thereby changing the light transmissivity of the LCD device.
Data Source
AI summary
A liquid crystal display device includes a gate line and a data line on a substrate crossing each other to define a pixel region; a thin film transistor in the pixel region and connected to the gate line and the data line; a pixel electrode in the pixel region and connected to the thin film transistor; and a gate pad at an end of the gate line and a data pad at an end of the data line, at least one of the gate pad and the data pad including: a pad electrode including at least one pad contact hole therein along with a passivation layer, the passivation layer on the pad electrode, at least one side of the pad contact hole having an uneven shape in plane; and a pad electrode terminal contacting inner side surfaces of the pad electrode surrounding the pad contact hole.