Flexible Display Terminal Structure for Crack-Free IC Bonding
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Solution Overview
Problem
The existing flexible organic EL display devices face challenges with cracking and increased manufacturing costs due to the high-temperature pressing process used for mounting electronic components, which affects the flexible panel's integrity and efficiency.
Innovation Solution
A display device configuration featuring a frame region with a terminal portion that includes an inorganic layered film and a flattening film with an organic insulating layer, where the flattening film covers the pads and an opening is formed to expose the inorganic layered film, allowing the anisotropic conductive film resin to move and reduce stress on the panel during the mounting process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If only an organic insulating film is provided on the terminal metal to reduce manufacturing cost, then manufacturing cost is reduced, but cracks occur in the flexible panel due to high-temperature pressing process
Solution Approach 1:
The terminal structure uses a composite layered configuration combining inorganic insulating films (first and second oxide conductive films) with an organic insulating film (flattening film). This composite structure provides both thermal resistance during high-temperature pressing and mechanical flexibility, preventing cracks while maintaining manufacturability.
Solution Approach 2:
The inorganic insulating films are formed beforehand on the terminal metal before the organic flattening film is applied. This pre-formed inorganic layer acts as a protective cushion during the high-temperature pressing process, preventing direct thermal stress on the flexible substrate and preventing cracks before they can occur.
2Reliability
If multiple oxide conductive films are formed on the terminal metal to prevent cracks, then panel integrity is improved, but manufacturing time increases
Solution Approach 1:
The first oxide conductive film and second oxide conductive film are merged into a single inorganic insulating film structure on the terminal metal. This consolidated approach provides the necessary thermal and mechanical protection without requiring separate processing steps for multiple distinct oxide layers, reducing manufacturing time while maintaining panel integrity.
3Reliability
If the flattening film covers the entire pad surface to protect the terminal, then panel integrity is improved, but stress concentration occurs during high-temperature pressing
Solution Approach 1:
The flattening film is selectively positioned to cover only specific portions of the terminal structure rather than the entire pad surface. This local coverage provides protection where needed while leaving other areas exposed to distribute thermal stress during high-temperature pressing, preventing stress concentration that would occur with complete coverage.
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 effectively suppresses cracking in the flexible panel and reduces manufacturing costs by minimizing stress and maintaining the integrity of the panel during electronic component mounting.
Implementation Method 1
a flattening film including an organic insulating film provided above the inorganic layered film and the pad column, the flattening film covering an end portion of each of the plurality of pads
Data Source
AI summary
A terminal portion provided in a frame region around a display region is provided with a resin substrate, an inorganic layered film provided above the resin substrate, a pad column provided above the inorganic layered film, the pad column including a plurality of pads arranged in a row electrically connected to a plurality of bumps provided on an IC chip via an ACF, and a flattening film including an organic insulating film provided above the inorganic layered film and the pad column, the flattening film covering an end portion of each of the plurality of pad, and an opening exposing the inorganic layered film is formed in the flattening film.