Display Pad Structure with Photosensitive Layers for Short Circuit Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display devices face challenges in achieving structural stability in the pad area, particularly when densely arranging signal pads, which can lead to defects like short circuits due to conductive balls.
Innovation Solution
The display device incorporates a pad structure with a lower conductive pattern, a first pattern made of negative photosensitive polymer, an upper conductive pattern overlapping the first pattern, and a second pattern made of positive photosensitive polymer or metal, along with a metal layer and insulating layers to enhance stability and prevent short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If signal pads are densely arranged in the pad area, then the productivity and integration of the display device is improved, but the reliability deteriorates due to short circuits caused by conductive balls
Solution Approach 1:
The patent removes the anisotropic conductive film containing conductive balls from the pad structure. Instead, it uses a planar conductive pattern structure with photosensitive materials that form a stable, short-circuit-free connection between the display panel and driving chip, thereby eliminating the harmful conductive balls while maintaining dense pad arrangement.
Solution Approach 2:
The patent introduces photosensitive materials (first and second photosensitive materials) as intermediaries between the lower and upper conductive patterns. These materials form a stable bonding interface through photopolymerization when exposed to light, providing reliable electrical connection without the need for conductive balls, thus enabling dense pad arrangement without short circuits.
2Ease of manufacture
If a simple pad structure is used, then the ease of manufacture is improved, but the structural stability deteriorates
Solution Approach 1:
The patent employs a composite structure combining conductive patterns with photosensitive materials (negative and positive photosensitive materials) and insulating layers. This composite construction provides enhanced structural stability, adhesion, and electrical connection reliability compared to simple conductive patterns, while still being manufacturable through standard photolithography processes.
Solution Approach 2:
The patent extends the pad structure into the vertical dimension by stacking multiple layers including lower insulating layers, lower conductive patterns, photosensitive material layers, upper conductive patterns, and upper insulating layers. This multi-layer configuration enhances structural stability and provides robust electrical connection without requiring complex lateral structures.
3Ease of operation
If anisotropic conductive films are used for bonding, then the ease of operation is improved, but the reliability deteriorates due to conductive ball defects
Solution Approach 1:
The patent completely removes the anisotropic conductive film from the bonding structure. The driving chip is bonded directly to the upper conductive pattern through a simplified process using non-conductive adhesive, eliminating the conductive balls that cause short circuits while maintaining ease of operation through direct bonding.
Solution Approach 2:
The patent replaces the expensive and unreliable anisotropic conductive film with a simple non-conductive adhesive layer. This adhesive serves its purpose during bonding and then remains as a stable insulating layer, providing a cost-effective and reliable solution that eliminates conductive ball defects.
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 configuration improves the structural stability of the display device, prevents defects like short circuits, and enhances the reliability of high-resolution display devices by eliminating the need for anisotropic conductive films.
Implementation Method 1
a first pattern disposed on the lower conductive pattern and including a first photosensitive material, an upper conductive pattern disposed on the lower conductive pattern and overlapping at least a portion of the first pattern, and a second pattern disposed on the first pattern and including a second photosensitive material different from the first photosensitive material
Data Source
AI summary
A display device includes a base layer including a display area including a light emitting element, and a non-display area which is adjacent to the display area and includes a pad, and a signal line connecting the light emitting element to the pad. In the non-display area, the pad includes a lower conductive pattern on the base layer, a first pattern on the lower conductive pattern and including a first photosensitive material, an upper conductive pattern on the lower conductive pattern and overlapping the first pattern, and a second pattern on the first pattern and comprising a second photosensitive material different from the first photosensitive material.