3D Clearance Calculation for Multi-Layer PCB Elements

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Solution Overview

Problem

Existing PCB design software cannot accurately determine minimum clearances between conductive elements in different conductive layers of multi-layer printed circuit boards, leading to time-consuming iterations and potential calculation errors that may result in failure under fault conditions.

Innovation Solution

A computer-implemented method that selects conductive elements from different outer layers, creates polygons to represent these elements, determines if there are conductive layers between them, and calculates the shortest unshielded distance using both in-plane and inter-layer distances, indicating a clearance violation if the calculated distance is less than the minimum spacing requirement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing PCB design software is used to determine minimum clearances, then single-layer clearance can be determined, but multi-layer clearance evaluation cannot be performed accurately

Engineering Contradiction:
Improveclearance measurement accuracyVSAvoidmulti-layer PCB evaluation capability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent extends clearance evaluation from 2D single-layer measurement to 3D multi-layer measurement by incorporating the Z-axis (vertical distance between layers). The system calculates true 3D clearance distances between conductive elements on different layers using the formula d = sqrt(dxy² + dz²), where dxy is the in-plane distance and dz is the inter-layer distance, thereby enabling accurate multi-layer PCB clearance evaluation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If manual eye-based determination is used for multi-layer clearances, then software limitations are bypassed, but evaluation time increases significantly

Engineering Contradiction:
Improveclearance evaluation accuracyVSAvoiddesign iteration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the manual visual inspection method with an automated computer-implemented algorithm. The system automatically selects conductive elements from different layers, calculates their 3D clearance distances using coordinate data, and compares results against minimum clearance requirements, eliminating the need for time-consuming manual eye-based determination while maintaining accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If iterative manual calculations are performed, then clearance compliance can be checked, but calculation errors may occur

Engineering Contradiction:
Improveclearance compliance verificationVSAvoidclearance calculation accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent implements a self-verification mechanism where the automated system performs consistent algorithmic calculations for all conductive element pairs. The system automatically determines minimum clearance distances, compares them against specified requirements, and identifies violations without human intervention, thereby eliminating calculation errors that occur in manual iterative processes and ensuring reliable compliance verification.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4510052A1Automated method for printed circuit board inter-layer element clearance
Publication Date: 2025.02.19 3M INNOVATIVE PROPERTIES CO
  • EP4510052A1 patent drawingFigure 1A
  • EP4510052A1 patent drawingFigure 1B
  • EP4510052A1 patent drawingFigure 2~3B

AI summary

A computer-implemented method for evaluating a minimum clearance distance between a first conductive element and a second conductive element included in a printed circuit board (PCB) is provided. The PCB comprises a plurality of conductive layers and a plurality of conductive elements, where each conductive layer comprises one or more conductive elements. The plurality of conductive layers comprises one or more outer conductive layers. The method comprises selecting a first conductive element (A) disposed on a first outer conductive layer and a second conductive element (B) disposed on a second outer conductive layer of the PCB, a clearance between which has a minimum spacing requirement. The method also comprises creating polygons of the first and second conductive elements, wherein a polygon of the first conductive element is A' and a polygon of the second conductive element is B'. The method also comprises determining if there is at least one conductive layer disposed between A' and B'. If no conductive layer is disposed between A' and B', then A" and B" are created on an evaluation layer. The method further comprises calculating a shortest unshielded distance (dxy) between A" and B". The method also comprises using a distance between the conductive layers (dz), and calculating a distance (d), wherein d=dxy2+dz2. If the calculated distance d is less than the minimum spacing requirement, a violation is indicated.