FPCB Guide Frame Stress Redirection in Display Apparatus
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Solution Overview
Problem
Flexible printed circuit boards (FPCBs) in display apparatuses are prone to cracking due to excessive bending and shear stress, leading to a shortened lifespan.
Innovation Solution
The design incorporates a mold frame with a guide frame that redirects the maximum bending stress away from the area of maximum shear stress, using a bent guide frame to distribute stress more evenly across the FPCB, thereby reducing both bending and shear stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the FPCB is made flexible to enable bending, then the FPCB can be easily bent and connected, but the FPCB is prone to cracking due to excessive bending and shear stress
Solution Approach 1:
A guide frame is introduced as an intermediary component between the FPCB and the mold frame. The guide frame redirects the bending stress away from the FPCB's vulnerable connection lines, allowing the FPCB to bend while preventing excessive stress concentration that would cause cracking.
Solution Approach 2:
The guide frame is designed with specific geometric parameters (convex bending shape, positioning relative to the FPCB's connection lines) that change the stress distribution parameters. By positioning the guide frame's convex portion at a distance greater than half the FPCB's width from the connection lines, the stress is redistributed to safer regions of the FPCB.
2Ease of operation
If the FPCB is bent toward the mold frame, then the FPCB can be connected to the PCB, but maximum bending stress and shearing stress are generated at different positions
Solution Approach 1:
The guide frame acts as a mediator that controls and redirects the stress distribution during bending. It ensures that the maximum bending stress and maximum shearing stress occur at different positions on the FPCB, preventing both types of stress from concentrating at the same vulnerable point (the connection lines).
Solution Approach 2:
The guide frame introduces asymmetric stress distribution by its convex bending shape and specific positioning. This asymmetry deliberately shifts the maximum bending stress away from the connection lines, creating a stress distribution pattern where bending and shearing stresses are separated in location rather than叠加 (superimposed) at the same point.
Data Source
AI summary
A display apparatus is disclosed. In one aspect, the display apparatus includes a first display substrate including i) a first plane on which an image is displayed and ii) a second plane opposite to the first plane. The display apparatus also includes a second display substrate formed at least partially overlapping second plane, a guiding portion bent and connected to at least one of the first and second display substrates, a mold frame accommodating and supporting the second display substrate, and a flexible printed circuit board (FPCB) including i) a first area attached to the second plane of the first display substrate and ii) a second area connected to and guided by the guiding portion, wherein the FPCB is bent at least partially around the mold frame.