Display FPCB Routing Structure for Backlight Stress Isolation
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Solution Overview
Problem
The deformation of the flexible printed circuit board (FPCB) in electronic devices leads to stress transfer to the back light unit (BLU) of the display, causing light refraction and local color changes in the display due to the internal structure of the device.
Innovation Solution
The electronic device incorporates guide members to manage the stress on the FPCB, either by guiding it in a specific direction or reducing its impact, thereby minimizing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the FPCB is made flexible to connect spaced-apart DDI and circuit board, then the device achieves high integration and compactness, but the FPCB deformation transfers stress to the backlight unit causing display defects
Solution Approach 1:
A stress relief structure is introduced as an intermediary element between the FPCB and the backlight unit. This structure absorbs and redistributes the stress generated by FPCB deformation, preventing it from being directly transferred to the backlight unit, thus eliminating display defects while maintaining FPCB flexibility
Solution Approach 2:
The stress relief structure modifies the mechanical parameters of the system by changing the stiffness distribution and stress transmission characteristics. It transforms the rigid stress transfer path into a controlled deformation path that protects the backlight unit from harmful stress
2Reliability
If the DDI and circuit board are placed apart to improve heat dissipation and signal interference, then device performance is improved, but the FPCB connection becomes more susceptible to deformation and stress
Solution Approach 1:
The stress relief structure adds a dimensional element to the FPCB assembly, creating a three-dimensional stress management system. This allows the FPCB to deform in controlled ways without compromising the structural integrity of the connection between DDI and circuit board
3Object-affected harmful factors
If the FPCB is constrained to reduce deformation, then stress transfer to backlight unit is reduced, but the flexibility and ease of assembly is compromised
Solution Approach 1:
The stress relief structure provides dynamic stress management by allowing controlled deformation in specific regions while maintaining stability in critical areas. This enables the FPCB to adapt during assembly and operation without requiring rigid constraints, preserving ease of assembly while reducing harmful deformation
Data Source
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AI summary
An electronic device is provided. The electronic device includes a housing, a display disposed inside the housing, the display disposed in a first direction so that a screen of the display is exposed to an outside of the housing, a first printed circuit board (PCB) disposed inside the housing, a flexible printed circuit board (FPCB) disposed inside the housing and including a first portion adjacent to the display and a third portion extending from the first portion and electrically connected with the first PCB, a first guide member disposed inside the housing, and a second guide member disposed inside the housing. At least a portion of the third portion may be disposed to pass between the first guide member and the second guide member. The at least the portion of the third portion may be provided with force in a second direction opposite to the first direction by the first guide member.