Anisotropic Conductive Layer Assembly for Display Pad Connectivity
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Solution Overview
Problem
Conventional display devices face defects such as shorts and opens during manufacturing due to the aggregation of conductive particles in anisotropic conductive layers, which affects the connectivity between electrodes.
Innovation Solution
The use of an anisotropic conductive layer with conductive particles having a core, a first conductive film exposing a portion of the core, and a second conductive film covering both the core and the first film, arranged to prevent overlap and ensure proper spacing, effectively addresses the defect issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive particles are used in the anisotropic conductive layer to ensure electrical connectivity, then electrical conductivity is improved, but short defects occur due to particle aggregation
Solution Approach 1:
The conductive particle is segmented into multiple functional layers: a core layer providing electrical conductivity, a first conductive film layer enhancing conductivity at the electrode interface, and a second conductive film layer providing overall conductivity and protection. This segmentation allows each layer to perform its specific function optimally while preventing harmful aggregation effects.
Solution Approach 2:
Different portions of the conductive particle have different properties: the core provides base conductivity, the first conductive film (with magnetic material) provides enhanced conductivity and magnetic response at the substrate interface, and the second conductive film provides overall conductivity and protection. This local quality optimization ensures proper electrical connectivity while controlling particle behavior during assembly.
Solution Approach 3:
The patent replaces purely electrical or chemical particle assembly mechanisms with a magnetic field-based assembly system. The magnetic member generates a magnetic field that causes conductive particles with magnetic materials to align and position themselves automatically, preventing aggregation-induced short defects while ensuring proper electrical connectivity between electrodes.
2Object-affected harmful factors
If conductive particles are arranged to prevent overlap to avoid short defects, then short defects are reduced, but open defects may occur due to insufficient connectivity
Solution Approach 1:
The conductive particle structure is segmented into multiple layers with different conductivity characteristics. The first conductive film provides localized conductivity enhancement at the electrode interface, while the second conductive film ensures overall conductivity. This segmentation allows particles to be spaced apart (preventing shorts) while maintaining reliable electrical connectivity through the multi-layer conductive structure.
Solution Approach 2:
The conductive particle is constructed as a composite material system combining a core material with first and second conductive film layers. This composite structure provides both the spacing capability (to prevent shorts) and the conductivity assurance (to prevent opens) by distributing conductive functions across multiple material layers.
3Ease of manufacture
If a simple conductive particle structure is used to reduce manufacturing complexity, then manufacturing is easier, but defect control (shorts and opens) becomes difficult
Solution Approach 1:
Rather than attempting to create a complex single-layer conductive particle with precise properties, the patent segments the particle into multiple simpler layers (core, first conductive film, second conductive film). Each layer can be manufactured and controlled independently, making the overall manufacturing process more manageable while achieving superior defect control through the combined functionality of all layers.
Solution Approach 2:
The patent changes the structural parameters of the conductive particle from a simple homogeneous structure to a multi-layer structure with different material properties and thicknesses. This parameter change enables better control over electrical conductivity, magnetic response, and spatial distribution, thereby improving defect control during manufacturing while remaining practically manufacturable.
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 prevents short and open defects by ensuring proper alignment and spacing of conductive particles, enhancing the reliability and efficiency of the display device manufacturing process.
Implementation Method 1
a magnetic member including a magnetic body; positioning a substrate including a display area and a pad area on the magnetic member
Implementation Method 2
when the at least one of heat and pressure to the anisotropic conductive film is applied, the conductive particles may be arranged to be spaced apart from each other due to magnetism of the magnetic member
Data Source
AI summary
A display device includes a substrate including a display area and a pad area, a plurality of pad electrodes disposed in the pad area on the substrate, a circuit board disposed to overlap at least a portion of the pad area on the substrate, and an anisotropic conductive layer disposed in the pad area between the substrate and the circuit board. The circuit board includes a base substrate and a plurality of bump electrodes disposed on a lower surface of the base substrate. The anisotropic conductive layer includes an adhesive layer and a plurality of conductive particles arranged in the adhesive layer. Each of the conductive particles includes a core, a first conductive film disposed on the core in a way such that at least a portion of the core is exposed, and a second conductive film entirely covering the core and the first conductive film.