Pad Area with Multiple Conductive Layers and Display Apparatus
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Solution Overview
Problem
The challenge in the field of display apparatuses is the need for a reliable test pad arrangement that minimizes dead space, allowing for efficient testing and separation after manufacturing, while ensuring the reliability and longevity of the display apparatus by preventing corrosion and lifting-off of conductive layers.
Innovation Solution
A display apparatus design featuring a substrate with a thin-film transistor, a non-display area, and a pad area with specific layer configurations, including a lower and upper conductive layer arrangement with insulating layers, and an upper conductive layer that extends into the space between the layers, providing shielding and increased reliability against corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a test pad is arranged outside the display area to minimize dead space, then the display area is maximized, but the reliability of the test pad structure decreases due to corrosion and lifting-off risks
Solution Approach 1:
The patent transitions from a conventional planar test pad structure to a three-dimensional structure by forming a groove in the substrate and filling it with conductive material. This vertical dimensionality change creates a recessed test pad structure that is isolated from the surface environment, preventing corrosion and lifting-off while maintaining full display area.
Solution Approach 2:
The patent introduces an insulating layer as an intermediary between the conductive test pad and the external environment. This insulating layer fills the groove and covers the conductive material, acting as a protective barrier that prevents direct exposure to corrosive elements while maintaining electrical connectivity through designated contact regions.
2Ease of manufacture
If laser trimming is performed to separate the test pad after testing, then the test pad can be removed, but the conductive layers are exposed to corrosion
Solution Approach 1:
The patent performs preliminary protective action by forming the insulating layer and groove structure before any trimming or separation operations. This pre-established protective framework ensures that when laser trimming occurs, the conductive layers remain protected within the groove structure, preventing exposure to corrosion even after separation.
Solution Approach 2:
The patent converts the potentially harmful laser trimming process into a beneficial operation by designing the groove structure to withstand and accommodate the trimming process. The trimming that would normally expose conductive layers to harm instead becomes a controlled separation process that maintains the protective enclosure of the conductive materials.
Data Source
AI summary
A display apparatus includes: a substrate including a thin-film transistor including an electrode, a non-display area, and a pad area including a lower and an upper conductive layer facing each other with an insulating layer therebetween. The lower conductive layer includes: a first conductive layer defining an end surface of the display apparatus, and a second conductive layer spaced apart from the first conductive layer to define a space between the first and second conductive layers, the insulating layer defines a first opening portion corresponding to the space, and the upper conductive layer is in a same layer as the electrode of the thin-film transistor, the upper conductive layer extending into the first opening portion corresponding to the space between the first and second conductive layers.