IPS LCD Terminal Portion Area Reduction via Vertical Stacking
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Solution Overview
Problem
The existing liquid crystal display devices face challenges in reducing the outer size, particularly due to the requirement for a large area of the earth pad and terminal portion to maintain adhesive strength and prevent external noise, which limits the downsizing of the panel.
Innovation Solution
The solution involves forming a shielding transparent conductive film on the counter substrate and an earth pad with a transparent conductive film on an organic passivation film, allowing wires to be formed below the earth pad, thereby reducing the terminal portion's area by utilizing the region below the earth pad as a wire region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large area earth pad is formed on the TFT substrate to maintain adhesive strength and prevent external noise, then the noise shielding and adhesive strength are improved, but the terminal portion area increases, preventing downsizing of the liquid crystal display panel
Solution Approach 1:
The patent utilizes the space dimension by forming wires below the organic passivation film in the terminal portion region. This allows the earth pad to be formed on the organic passivation film while wires are positioned in the underlying space, effectively using vertical stacking to resolve the area conflict between noise shielding requirements and panel downsizing goals
Solution Approach 2:
The terminal portion region is designed to serve multiple functions simultaneously: it houses the earth pad for noise shielding and adhesive strength, while also containing wires for electrical connections below the organic passivation film. This multi-functional design allows the same area to fulfill both shielding requirements and wiring needs without increasing overall terminal portion area
2Area of stationary object
If the terminal portion area is reduced to enable downsizing of the liquid crystal display panel, then the panel size is decreased, but the adhesive strength and noise shielding capability are compromised
Solution Approach 1:
By positioning wires in the space below the organic passivation film rather than requiring them to occupy the same planar area as the earth pad, the invention maintains both adequate earth pad area for shielding and adhesive strength while minimizing the overall terminal portion footprint for panel downsizing
3Reliability
If a conductive tape is used to connect the earth pad to the shielding ITO, then the noise shielding is achieved, but the earth pad requires a large area to maintain adhesive strength
Solution Approach 1:
The conductive tape connection is positioned in the space below the organic passivation film, allowing the earth pad on the organic passivation film to be smaller while still maintaining adequate adhesive strength. The vertical stacking separates the adhesive function from the electrical connection function, reducing the area requirement for the earth pad
Data Source
AI summary
In an IPS-mode liquid crystal display device, the area of a terminal portion is decreased. A liquid crystal display device includes a TFT substrate and a counter substrate attached to the TFT substrate with a sealing material, and includes a display region and a terminal portion formed on the TFT substrate. A shielding transparent conductive film is formed on the outer side of the counter substrate. On the terminal portion, an earth pad formed with a transparent conductive film is formed on an organic passivation film. The shielding transparent conductive film is connected to the earth pad through a conductor. Below organic passivation film of the terminal portion, a wire is formed.