PCB Inductor Coil Presence Detection for Notebook Cover Intrusion

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Solution Overview

Problem

Existing intrusion detection systems in notebook computers are vulnerable to tampering as they do not trigger an alert when the cover is opened without removing screws, and adding multiple intrusion detection switches is costly and space-consuming.

Innovation Solution

A circuit board with an inductor coil around a hole measures electrical quantities induced by an alternating current to detect the presence of objects, determining if an object is within the hole based on these measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple intrusion detection switches are included to detect cover removal, then the detection reliability is improved, but the device complexity and space consumption increase

Engineering Contradiction:

Improveintrusion detection reliabilityVSAvoidnumber of intrusion detection switches

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical intrusion detection switches with an electromagnetic sensing system. An inductor coil is positioned near the chassis opening, and changes in its electromagnetic field caused by the presence or absence of the cover indicate intrusion. This substitution eliminates the need for multiple mechanical switches while maintaining detection reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an electromagnetic field as an intermediary between the cover and the detection system. Instead of direct mechanical contact between switches and cover, the electromagnetic field mediates the detection process by sensing changes in permeability or inductance when the cover is removed, thereby reducing the number of physical components needed.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If multiple intrusion detection switches are included to detect cover removal, then the detection reliability is improved, but the manufacturing cost increases

Engineering Contradiction:

Improveintrusion detection reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive mechanical intrusion detection switches with a more cost-effective electromagnetic sensing system. The inductor coil and associated circuitry are less expensive to manufacture and assemble compared to multiple mechanical switches, while achieving the same or better detection reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The inductor coil serves multiple functions: it is part of the normal circuit board functionality and simultaneously acts as the intrusion detection sensor. This multi-functionality reduces the need for separate dedicated intrusion detection components, thereby lowering manufacturing costs.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If traditional intrusion switches are used, then the detection of cover removal is possible, but the detection of cover opening without screw removal fails

Engineering Contradiction:

Improvedetection accuracyVSAvoiddetection scenario coverage

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces mechanical switches that only detect discrete states (switch pressed or not) with an electromagnetic sensing system that can detect continuous changes in the electromagnetic field. This allows detection of various intrusion scenarios including cover opening without screw removal, as the electromagnetic field changes continuously as the cover moves away from its sealed position.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transitions from static mechanical switch detection to dynamic electromagnetic field detection. The electromagnetic field continuously monitors the space near the chassis opening, detecting changes as the cover moves during removal or opening processes, thereby covering multiple intrusion scenarios with a single dynamic sensing mechanism.

Inventive Principle:

Principle #15Dynamics

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

Effectively detects unauthorized access to the internal components of a notebook computer without requiring additional space or significant cost, providing reliable intrusion detection.

Implementation Method 1

measuring an electrical quantity occurring within the inductor coil responsive to an alternating current driven to the inductor coil

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS12510566B2Systems and methods for detection of presence of non-electrical component

Publication Date: 2025.12.30 DELL PROD LP

AI summary

A system may include a circuit board comprising a inductor coil formed in a circuit board around a hole formed through the circuit board and a presence detection subsystem configured to measure an electrical quantity occurring within the inductor coil responsive to an alternating current driven to the inductor coil and determine whether an object is present within the hole based on the electrical quantity.