Backplane Circuit Board Resin Creep Prevention

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current methods for producing backplane circuit boards in on-board avionics systems face issues such as excessive cost, obsolescence, mediocre electromagnetic compatibility, and the risk of resin rising in blind holes, leading to connection failures and dimensional restrictions.

Innovation Solution

A process involving a three-layered backplane circuit board structure with zones cleared of material in the bonding layers to prevent resin creep, combined with conductive pads and recesses to absorb and limit resin movement, ensuring blind holes are formed at maximum depth for connection spindles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a three-layered backplane circuit board structure with bonding layers is used, then the mechanical strength and electrical insulation are improved, but the resin may rise in the blind holes during assembly, causing connection failures

Engineering Contradiction:

Improvemechanical strengthVSAvoidconnection reliability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The invention extracts the harmful resin material from the blind hole regions by creating zones cleared of bonding material directly above and below each blind hole. This removal prevents the resin from rising into the blind holes during assembly while maintaining the overall three-layered bonding structure for mechanical strength and electrical insulation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention applies local quality by creating specific zones cleared of bonding material only in the regions directly above and below the blind holes, while maintaining bonding layers in other areas. This localized modification prevents resin rise exactly where needed without compromising the overall structural integrity and electrical insulation provided by the bonding layers.

Inventive Principle:

Principle #3Local quality

2Reliability

If blind holes are made deeper to accommodate connection spindles effectively, then the connection reliability is improved, but the resin rising risk increases

Engineering Contradiction:

Improveconnection reliabilityVSAvoidresin rising

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention extracts the resin material from the critical zones above and below blind holes, creating clearance zones that prevent resin rise. This allows blind holes to be made deeper for better spindle accommodation without the resin rising into the holes, as the harmful resin has been removed from those specific regions.

Inventive Principle:

Principle #2Taking out (Extraction)

3Object-affected harmful factors

If conventional wrapping method is used to connect external connector to backplane circuit board, then the electromagnetic compatibility is improved, but the production cost increases excessively

Engineering Contradiction:

Improveelectromagnetic compatibilityVSAvoidproduction cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The invention replaces the complex mechanical wrapping process with a simplified PCB manufacturing process. Instead of manually wrapping wires around spindles, the electrical connections are created through standard PCB techniques including drilling, plating, and soldering of blind holes, significantly reducing production cost while maintaining electromagnetic compatibility through controlled impedance design.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Object-affected harmful factors

If zones cleared of material are created in bonding layers, then the resin rising is prevented, but the manufacturing complexity increases

Engineering Contradiction:

Improveresin risingVSAvoidmanufacturing complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention applies preliminary action by creating zones cleared of bonding material during the PCB manufacturing process, before the actual assembly takes place. This pre-clearing of zones ensures that when bonding layers are applied and resin is introduced, it cannot rise into the blind holes, as the path has already been blocked by the absence of bonding material in those specific zones.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11350530B2Method for producing a backplane circuit board

Publication Date: 2022.05.31 SAFRAN ELECTRONICS & DEFENSE (FR)

AI summary

A process for producing a backplane circuit board (20) having an internal face (142) adapted to be connected to connectors (13) of circuit boards (12) and an external face (143) adapted to be connected to an external connector (15), blind holes (146, 148) opening on the internal face (142) and external face (143) of the backplane circuit board (20), wherein bonding layers (31, 32) having zones (41, 42) cleared of material facing the blind holes are used between the printed circuits (21, 22, 23).