Flexible Display Circuit Bump Layout for Mounting Reliability
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Solution Overview
Problem
Display devices with flexible substrates face issues with durability and reliability due to detachment of the display unit when the substrate is bent during the mounting of the driving circuit, particularly during pressing and heating processes.
Innovation Solution
The display device incorporates a flexible base layer with a specific arrangement of bumps on the driving circuit, including first, second, and third bumps, where the third bump is strategically positioned between the end of the flexible base layer and the first bump, and the bumps are arranged with acute or obtuse angles relative to a reference line, ensuring even pressure distribution and preventing the substrate from bending during mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the substrate is made of flexible material to enable bending, then adaptability is improved, but the display unit may be detached from the substrate during pressing and heating processes
Solution Approach 1:
The driving circuit is divided into multiple bump units arranged in specific patterns (first bumps in first row, second bumps in second row, third bumps in third row). This segmentation allows different regions to serve different functions: outer bumps (first and second bumps) prevent substrate bending, while inner bumps (third bumps) provide electrical connections, thus maintaining both flexibility and reliability
Solution Approach 2:
Different regions of the driving circuit are assigned different functions based on their location. The bumps closer to the display unit (first and second bumps in outer rows) are specifically arranged to prevent substrate bending during pressing, while the third bumps in the inner row are optimized for electrical connection. This local differentiation resolves the contradiction between flexibility and attachment reliability
2Productivity
If the driving circuit is mounted through pressing and heating processes, then manufacturing efficiency is improved, but the substrate bends causing display unit detachment
Solution Approach 1:
The bump units are pre-configured in specific patterns before the pressing and heating mounting process. The first and second bumps are positioned in outer rows at distances optimized to prevent substrate bending during the subsequent pressing operation. This preliminary arrangement ensures that when pressing and heating are applied for mounting, the substrate maintains structural integrity and the display unit remains attached
Solution Approach 2:
The specifically arranged bump units act as intermediaries between the pressing force and the substrate. The outer bumps (first and second bumps) are positioned to distribute and control the pressing force, preventing excessive bending of the flexible substrate during the mounting process, thus enabling high-speed mounting while maintaining reliability
Data Source
AI summary
The display device includes a flexible base layer including a first region and a second region located around the first; a display unit on one surface of the first region and including a light emitting element; a driving circuit on the second region and including a plurality of first bumps arranged in a first row and a plurality of second bumps arranged in a second row, the driving circuit includes a third bump in the first row and disposed outward relative to the plurality of first bumps, a first and second reference bump each disposed at a center of the plurality of first and second bumps that are disposed along a reference line defined in a column direction vertically intersecting a row direction, the remaining first and second bumps excluding the first reference bump and the second reference bump arranged to have a preset slope with respect to the reference line.