Floating Terminal Bonding Structure for Crack-Resistant OLED Modules
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Solution Overview
Problem
In the production of OLED display modules with integrated touch functionality, the narrow bonding area between the substrate and flexible circuit board leads to insufficient adhesive force, resulting in cracks during the bending process, which can cause touch non-sensing defects.
Innovation Solution
The module structure incorporates floating terminals on both sides of the bonding terminals, increasing the effective bonding area and using a 'V'-shaped opening in the polarizer to disperse stress, thereby preventing cracks from expanding to the bonding terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a touch module is externally hung on an OLED display module, then the display function and touch function are integrated, but the bonding area becomes narrower, leading to inadequate adhesive force and increased bending stress
Solution Approach 1:
The bonding area is segmented into multiple regions: a first bonding area for bonding the flexible circuit board, a second bonding area for bonding the touch sensor, and a third bonding area for bonding the OLED display module. This segmentation allows each bonding area to be optimized independently, with the flexible circuit board bonding area being sufficiently large to provide adequate adhesive force while maintaining overall integration.
Solution Approach 2:
The patent introduces a transition area that extends in a direction different from the conventional bonding area arrangement, effectively utilizing three-dimensional space. The transition area connects the flexible circuit board bonding area with the touch sensor bonding area, allowing stress to be distributed across multiple dimensions and reducing the concentration of bending stress in any single plane.
2Volume of moving object
If the bonding area is narrowed to achieve compact integration, then the module size is reduced, but the adhesive force becomes inadequate and bending stress increases
Solution Approach 1:
The bonding structure is divided into multiple specialized bonding areas, each optimized for its specific function. The flexible circuit board bonding area is designed with sufficient size to provide adequate adhesive force, while the touch sensor and OLED bonding areas are positioned to minimize overall module footprint. This segmentation allows the module to maintain compact size without compromising bonding strength.
Solution Approach 2:
Different regions of the bonding structure are given different properties: the flexible circuit board bonding area is designed with larger area and optimized geometry for high adhesive force, while the transition area is designed with specific shape characteristics to reduce stress concentration. This local optimization allows each region to perform its function effectively while maintaining overall compactness.
3Productivity
If the bonding area is reduced for compact design, then integration density increases, but bending stress on the flexible circuit board increases causing signal line cracks
Solution Approach 1:
The transition area is designed to extend in a direction perpendicular to the conventional bonding arrangement, utilizing three-dimensional space to distribute stress. This dimensional change allows the flexible circuit board to be bonded with sufficient area for reliability while maintaining high integration density in the planar view, as the stress distribution occurs in multiple spatial dimensions.
Solution Approach 2:
The transition area is designed in advance to provide a stress-relief pathway before the flexible circuit board undergoes bending during operation. By pre-configuring the bonding geometry with optimized shapes and dimensions in the transition area, the patent prevents stress concentration from developing into cracks that would compromise signal line integrity.
4Strength
If floating terminals are added to increase bonding area, then adhesive force and stress resistance improve, but device complexity increases
Solution Approach 1:
The floating terminals are designed to serve multiple functions: they provide additional bonding area to increase adhesive force, act as stress-distribution elements to reduce bending stress concentration, and maintain electrical isolation where needed. This multi-functionality allows the terminal structure to improve strength without requiring separate dedicated components for each function, thereby limiting the increase in overall device complexity.
Data Source
AI summary
A module structure, a touch module, a display module and a display apparatus are provided. The module structure includes: a substrate including a base substrate, wherein the base substrate includes a functional area and a bonding area on one side of the functional area; a plurality of bonding terminals are provided in the bonding area and arranged along a first direction and each bonding terminal extends along a second direction, and at least one floating terminal is provided in the bonding area and on at least one side of the plurality of bonding terminals in the first direction; the module structure further includes a flexible circuit board, including: a plurality of first connection terminals provided corresponding to the plurality of bonding terminals, and at least one second connection terminal provided corresponding to the at least one floating terminal.