Display Panel Adhesive Layer Structure for Reliable Pad Connections
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Solution Overview
Problem
Existing flexible display devices face challenges in maintaining reliability and minimizing damage and manufacturing costs when portions are bendable, particularly in the connection of circuit boards and driving circuit chips due to potential connection failures from conductive balls in anisotropic conductive films.
Innovation Solution
A display device design with a specific adhesive layer configuration, including a second adhesive layer with a uniform thickness less than the first, spaced apart from the first adhesive layer, and a method involving pre-pressing steps to ensure uniform adhesive thickness, preventing connection failures by managing conductive balls in anisotropic conductive films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform adhesive layer thickness is used in the pad area, then manufacturing simplicity is maintained, but connection reliability deteriorates due to conductive ball massing in anisotropic conductive films
Solution Approach 1:
The patent applies different adhesive layer thicknesses in different regions: the first adhesive layer in the display area has a first thickness, while the second adhesive layer in the pad area has a second thickness that is different from the first thickness. This local differentiation resolves the contradiction by optimizing each region's adhesive thickness for its specific function, improving connection reliability in the pad area while maintaining manufacturing feasibility through a systematic multi-layer approach.
Solution Approach 2:
The adhesive layer is segmented into multiple distinct layers: a first adhesive layer covering the display area and a second adhesive layer covering the pad area. This segmentation allows each layer to be independently optimized for its specific region's requirements, enabling different thicknesses and potentially different materials to be used in different areas, thereby resolving the contradiction between manufacturing simplicity and connection reliability.
2Reliability
If the adhesive layer thickness varies in the pad area, then connection reliability improves by preventing conductive ball massing, but manufacturing complexity increases
Solution Approach 1:
The adhesive system is divided into multiple segments or layers, with each layer having specific thickness characteristics suited to its region. The first adhesive layer and second adhesive layer are distinct segments that can be applied through separate processes or as part of a coordinated multi-step manufacturing process, managing the complexity through systematic segmentation.
Solution Approach 2:
The patent employs preliminary pressing steps before final assembly to pre-adhere the anisotropic conductive film and establish proper adhesive layer thickness. This preliminary action prevents conductive ball massing by ensuring correct positioning and thickness before the final connection process, thereby improving reliability while managing manufacturing complexity through a structured multi-step approach.
3Ease of manufacture
If pressing force is applied uniformly across the display module, then manufacturing process simplicity is maintained, but adhesive thickness uniformity deteriorates in the pad area
Solution Approach 1:
The patent implements preliminary pressing steps that apply pressure before final assembly to pre-adhere the anisotropic conductive film and establish the desired adhesive layer thickness. This preliminary action ensures proper thickness precision in the pad area by setting the adhesive layers in their correct positions before the final uniform pressing step, resolving the contradiction between process simplicity and thickness precision.
Solution Approach 2:
The pressing process is segmented into multiple steps with different pressure applications: preliminary pressing steps that apply specific pressure to achieve proper adhesive thickness, and final pressing steps that complete the assembly. This segmentation of the pressing process allows each step to serve a specific function, maintaining both manufacturing feasibility and adhesive thickness precision.
Data Source
AI summary
A display device includes a display panel, a circuit board, a first conductive film, first and second lower films, and first and second adhesive layers. The display panel includes a display area and a pad area which includes a first pad part. The circuit board is attached on the display panel and includes a lead part overlapping the first pad part. The first conductive film is between the display panel and the circuit board and electrically connects the first pad part and the lead part to each other. The first and second lower films are attached to the display panel to respectively correspond to the display area and the pad area. A thickness of the second adhesive layer between the display panel and the second lower film is less than a thickness of the first adhesive layer between the display panel and the first lower film.