Flexible Printed Circuit Coverlay Holes for Warp-Free Antenna Lamination

Solution Overview

Problem

Warping and poor fittingness of flexible printed circuits (FPC) occur during surface mounting technology (SMT) and lamination processes due to uneven heating and bubble formation, affecting antenna characteristics and efficiency.

Innovation Solution

Incorporating coverlay holes and through holes in the FPC structure, and pierced or aligned holes in the magnetic layer, to improve warping and attachment fit during SMT and lamination, enhancing the FPC's flexibility and magnetic layer integration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the FPC is heated during SMT process, then the electronic elements can be mounted on the FPC, but small bubbles inside the cover layer cause uneven heating and warping

Engineering Contradiction:

ImproveSMT mounting capabilityVSAvoidFPC flatness

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The cover layer is segmented by forming multiple through holes that penetrate through it, dividing the continuous cover layer into regions separated by these holes. This segmentation allows heat to pass through more uniformly and prevents bubble accumulation that causes warping during SMT heating.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cover layer is modified locally by creating through holes at specific positions where bubbles tend to form. This local modification allows heat to penetrate through the cover layer at these critical points, preventing uneven heating and warping in those specific areas without affecting the overall integrity of the FPC.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If a magnetic layer is laminated on the FPC for EMI shielding, then electromagnetic wave interference is reduced, but small bubbles are generated during lamination causing poor attachment

Engineering Contradiction:

ImproveEMI shieldingVSAvoidAttachment quality

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The cover layer is segmented by forming multiple through holes that penetrate through it, dividing the continuous cover layer into regions separated by these holes. This segmentation allows heat to pass through more uniformly and prevents bubble accumulation that causes warping during SMT heating.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cover layer is modified locally by creating through holes at specific positions where bubbles tend to form. This local modification allows heat to penetrate through the cover layer at these critical points, preventing uneven heating and warping in those specific areas without affecting the overall integrity of the FPC.

Inventive Principle:

Principle #3Local quality

3Weight of moving object

If the FPC is made thin and light for wearable devices, then portability is improved, but the FPC becomes more susceptible to warping during heating

Engineering Contradiction:

ImproveFPC weightVSAvoidFPC dimensional stability

Core Design Contradiction:

Weight of moving objectVSStability of the object's composition

Solution Approach 1:

The cover layer is segmented by forming multiple through holes that penetrate through it, dividing the continuous cover layer into regions separated by these holes. This segmentation allows heat to pass through more uniformly and prevents bubble accumulation that causes warping during SMT heating.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cover layer is modified locally by creating through holes at specific positions where bubbles tend to form. This local modification allows heat to penetrate through the cover layer at these critical points, preventing uneven heating and warping in those specific areas without affecting the overall integrity of the FPC.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12513820B2Flexible printed circuit and antenna structure

Publication Date: 2025.12.30 WISTRON NEWEB CORP

AI summary

A flexible printed circuit and an antenna structure are provided. The flexible printed circuit has a main body part and a bending part and includes a substrate, two copper foil layers, and two coverlays. The substrate includes a first surface and a second surface, and one surface of each of the two copper foil layers is disposed on the first surface and the second surface of the substrate, respectively. Each of the two coverlays is disposed on another surface of each of the two copper foil layers. Each of the two coverlays includes at least two coverlay holes, and the at least two coverlay holes penetrate through the coverlay and are disposed on the main body part.