Display Device Contact Hole Segmentation for Bezel Reduction
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Solution Overview
Problem
Existing display devices face challenges in minimizing the non-display area, which can lead to bending defects and increased bezel areas, particularly when trying to integrate flexible circuit boards without high-temperature processing.
Innovation Solution
A display device design featuring a flexible circuit board bonded to the rear surface of the display panel using a pad electrode and synthetic resin layers, with strategically arranged contact holes to reduce defects and bezel area, and a metal pattern formed by curing metal ink at low temperatures for electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the non-display area is minimized to reduce bezel size, then the display area ratio is improved, but bending defects occur and manufacturing reliability deteriorates
Solution Approach 1:
The contact hole structure is segmented into multiple levels: a first contact hole penetrating the second synthetic resin layer, insulating layers disposed within it, and a second contact hole penetrating the insulating layers to expose the pad electrode. This segmentation allows the non-display area to be minimized while maintaining structural integrity and preventing bending defects through the distributed contact architecture.
Solution Approach 2:
The solution transitions from a single-plane contact structure to a multi-dimensional hierarchical structure with contact holes at different depths and insulating layers arranged in specific spatial configurations. This dimensional approach enables reduced non-display area while maintaining reliable electrical connections and preventing bending defects.
2Strength
If high-temperature processing is used to bond the flexible circuit board, then bonding strength is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The bonding process parameters are changed from high-temperature processing to low-temperature curing. The metal ink is cured at reduced temperatures, enabling the flexible circuit board to be bonded to the display panel without requiring high-temperature equipment, thereby simplifying the manufacturing process while maintaining adequate bonding strength.
Solution Approach 2:
The patent employs metal ink that can be cured at low temperatures instead of requiring high-temperature bonding materials. This approach uses more readily available, easier-to-process materials that simplify the manufacturing workflow, even if the bonding strength is slightly reduced compared to high-temperature methods.
3Area of stationary object
If the non-display area is reduced, then the bezel area is minimized, but the structural integrity and electrical connection reliability worsen
Solution Approach 1:
The electrical connection structure is nested with the pad electrode positioned at the bottom, followed by insulating layers, then the first contact hole, and finally the second contact hole penetrating through to establish electrical connection. This nested arrangement enables precise electrical connections even when the non-display area is minimized, as each layer is strategically positioned to maintain connection integrity.
Solution Approach 2:
The pad electrode is pre-positioned and exposed through the first contact hole before the second contact hole is formed. This preliminary arrangement of the electrical connection pathway ensures that subsequent processing steps can accurately establish the electrical connection between the flexible circuit board and the display panel, maintaining manufacturing precision despite reduced non-display area.
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 effectively reduces the non-display area, prevents bending defects, and allows for bonding without high-temperature processing, thereby minimizing bezel size and enhancing the display's structural integrity and manufacturing efficiency.
Implementation Method 1
a metal pattern formed by curing metal ink at low temperatures for electrical connection
Data Source
AI summary
A display device includes a display panel. The display panel includes a pixel, an encapsulation layer, and a connection electrode connecting a signal line and a pad electrode. The connection electrode is connected to the pad electrode via a first contact area positioned in a non-display area. A first contact hole is defined penetrating the second synthetic resin layer in the first contact area, a plurality of insulating layers is disposed in the first contact hole, and a second contact hole is defined inside the first contact hole in a plan view, penetrates the insulating layers, and exposes the pad electrode. The first contact hole has a width greater than a width of the second contact hole in the plan view.