Flexible Printed Circuit Slits for Curved Display Adhesion
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Solution Overview
Problem
Flexible display devices face challenges in maintaining adhesion and preventing connection defects when the substrate is curved, due to stress applied to the flexible printed circuit (FPC) attached to the substrate, which can lead to misalignment and weakened bonding between the FPC and the substrate.
Innovation Solution
The FPC attachment parts include slits that divide them into multiple parts, with bumps and pads arranged to correspond in shape and orientation, and are connected using an anisotropic conductive film, allowing for stress reduction and improved alignment even when the substrate is curved, thereby enhancing adhesion and preventing connection defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the FPC is attached to the curved substrate without slits, then the electrical connection is maintained, but stress accumulates causing misalignment and adhesion weakening
Solution Approach 1:
The attachment part of the FPC is divided into multiple segments by introducing slits, allowing each segment to independently accommodate stress from substrate curvature while maintaining overall electrical connection integrity
Solution Approach 2:
The slits are strategically positioned at specific locations within the attachment part where stress concentration occurs due to curvature, creating localized flexibility zones that relieve stress without compromising the overall structural integrity or electrical connection
2Adaptability or versatility
If the substrate is curved to provide stereoscopic display, then the display effect is improved, but the FPC attachment becomes misaligned and connection defects occur
Solution Approach 1:
The FPC attachment part is segmented by slits to allow differential movement and deformation across the curved substrate surface, maintaining alignment precision despite the overall curvature
Solution Approach 2:
The attachment part is designed to be dynamically adaptable to the curved substrate shape through the slits, allowing the structure to flex and conform to the curvature while maintaining proper bump-to-pad alignment
3Stability of the object's composition
If the FPC attachment part is made rigid to ensure structural stability, then the structural stability is improved, but stress concentration increases causing connection defects
Solution Approach 1:
The attachment part is divided into rigid segments separated by slits, maintaining structural stability within each segment while allowing stress relief at the slit boundaries to prevent connection defects
Solution Approach 2:
The attachment part combines rigid FPC material with controlled flexibility through slits, creating a composite structure that exhibits both structural stability and stress relief capabilities
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
The slits in the FPC attachment parts effectively reduce stress and maintain alignment between pads and bumps, preventing adhesion weakening and connection defects in curved substrates, ensuring reliable electrical connections in flexible display devices.
Implementation Method 1
The pad part and the attachment part may be electrically connected to each other by an anisotropic conductive film (ACF)
Data Source
AI summary
A display device including a flexible substrate that includes a display part to display an image; a driving integrated chip (IC) that supplies a driving voltage to the display part; a flexible printed circuit (FPC) attached to an outer side portion of the substrate; and a printed circuit board (PCB) attached to the FPC, the PCB transferring the driving voltage to the driving IC through the FPC, wherein the FPC includes attachment parts at ends thereof, the attachment parts of the FPC being attached to pad parts at the outer side portion of the substrate and to pad parts of the PCB, and the attachment parts include slits therein.