EMI Shielding Frame and Cover Assembly with Multi-Position Latching

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Solution Overview

Problem

Electronic equipment faces inefficiencies due to electromagnetic interference (EMI) and radio frequency interference (RFI), which require effective shielding, and excessive heat generation that reduces product life and reliability, with existing shielding methods being costly and time-consuming to repair.

Innovation Solution

The development of EMI shielding and thermal management assemblies with multi-position latching frames and covers, incorporating thermally-conductive materials and phase change materials that provide both EMI shielding and heat dissipation by forming a thermally-conducting heat path from electrical components to the cover, allowing for easy attachment and detachment during solder reflow processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If soldered shields are used for EMI shielding, then EMI protection is provided, but repair and replacement becomes expensive and time-consuming

Engineering Contradiction:

ImproveEMI shielding effectivenessVSAvoidRepair time and cost

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The EMI shield is divided into a frame portion and a cover portion that can be separately assembled and disassembled. The frame is soldered to the PCB while the cover can be independently removed for access to enclosed components, enabling repair without complete disassembly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention combines EMI shielding functionality with thermal management by integrating a heat sink into the cover portion. This merged structure provides both electromagnetic protection and heat dissipation while maintaining ease of repair through modular assembly.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If shields are soldered to the PCB, then EMI shielding is achieved, but the overall size of the PCB increases

Engineering Contradiction:

ImproveEMI shielding effectivenessVSAvoidPCB area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The EMI shielding structure transitions from a two-dimensional PCB-mounted shield to a three-dimensional assembly with vertical walls and a cover. This dimensional change provides effective EMI shielding and thermal management without increasing the PCB footprint area.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Temperature

If thermal interface material is placed in contact with electrical components, then heat dissipation is improved, but thermal impedance remains high before solder reflow

Engineering Contradiction:

ImproveHeat dissipation efficiencyVSAvoidThermal impedance

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The cover and frame are designed with different thermal expansion coefficients. During solder reflow heating, the frame expands more than the cover, creating gaps that allow thermal interface material to compress against the heat sink. Upon cooling, the frame contracts more, maintaining compression on the thermal material for optimal thermal contact.

Inventive Principle:

Principle #37Thermal expansion

Solution Approach 2:

The patent utilizes changes in physical parameters (thermal expansion coefficients, phase change of solder material) during the solder reflow process to automatically adjust the contact pressure between thermal interface materials and heat dissipation components, optimizing thermal impedance without manual intervention.

Inventive Principle:

Principle #35Parameter changes

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 solution effectively reduces thermal impedance, enhances heat dissipation, and simplifies the repair process by providing a cost-effective and efficient means of EMI shielding and thermal management, improving the reliability and lifespan of electronic components.

Implementation Method 1

the at least one thermally-conductive compliant material forms a thermally-conducting heat path from the one or more electrical components to the cover

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a thermal interface/phase change material. Before solder reflow of the frame to the board, a spaced distance is provided between the thermal interface/phase change material and the one or more electrical components

Methodology Applied

Scientific EffectPhase change: Phase Change

Implementation Method 3

After solder reflow and cooling, however, displacement of the thermal interface/phase change material and thermal contraction of the cover can cooperatively generate a clamping force for compressing the thermal interface/phase change material

Methodology Applied

Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentUS7623360B2EMI shielding and thermal management assemblies including frames and covers with multi-position latching

Publication Date: 2009.11.24 LAIRD TECHNOLOGIES INC

AI summary

According to various aspects of the present disclosure, exemplary embodiments are of assemblies capable of providing board level EMI shielding and heat dissipation of one or more electrical components. Other aspects relate to components of such assemblies. Further aspects relate to methods of using EMI shielding and thermal management assemblies. Additional aspects relate to methods of making EMI shielding and thermal management assemblies, and methods of making the components thereof.