Flat Panel Display Touch Screen Ground Line Contact
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Solution Overview
Problem
Capacitive touch screen panels in flat panel display devices often experience signal failures due to parasitic capacitance between conductive lines and metal-based black matrices, which affects the operation characteristics and reliability of the touch screen functionality.
Innovation Solution
Incorporating a ground line contact made of the same material as the ground line, directly connecting it to the black matrix, and optionally using a transparent conductive oxide layer to prevent parasitic capacitance between conductive lines and the black matrix, thereby enhancing the operational characteristics of the touch screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a metal-based black matrix is used in the touch screen panel, then the aesthetic appearance and light blocking performance are improved, but parasitic capacitance is generated between conductive lines and the black matrix causing signal failures
Solution Approach 1:
A ground line contact structure is introduced as an intermediary element between the black matrix and the ground line. This contact structure provides a dedicated electrical connection path that eliminates parasitic capacitance effects by directly grounding the black matrix at multiple points, thereby preventing signal interference while maintaining the metal-based black matrix for aesthetic and optical performance
Solution Approach 2:
The ground line contact structure establishes equipotential regions by connecting the black matrix to the ground line at multiple locations. This creates equal potential zones that prevent voltage differences and parasitic capacitance accumulation between the black matrix and conductive lines, eliminating signal failure issues while preserving the metal black matrix design
2Reliability
If the ground line contact is made of the same material as the ground line, then the electrical conductivity and connection reliability are improved, but the manufacturing complexity increases due to material matching requirements
Solution Approach 1:
The ground line contact is fabricated from the same material as the ground line, creating homogeneous material properties throughout the conductive structure. This ensures consistent electrical conductivity and thermal expansion characteristics, improving connection reliability and reducing interface failures while simplifying the manufacturing process by eliminating material transitions
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
The solution effectively prevents parasitic capacitance, improving signal reliability and overall operation characteristics of the flat panel display device with touch screen functionality.
Implementation Method 1
Capacitive touch screen panels in flat panel display devices often experience signal failures due to parasitic capacitance between conductive lines and metal-based black matrices
Implementation Method 2
a transparent conductive oxide layer disposed between the conductive line and the overcoat layer, wherein the transparent conductive oxide layer electrically connects the conductive line and the sensing pattern
Data Source
AI summary
A flat panel display device with touch screen is provided. The flat panel display device includes a substrate, a black matrix, a ground line, and a ground line contact. The substrate includes an active region, and an inactive region surrounding the active region. The black matrix is disposed on the substrate in the inactive region, and includes a metal. The ground line is disposed on the black matrix, in the inactive region. The ground line contact electrically connects the ground line to the black matrix.