Steering Wheel Heater Electrodes for Occupant Sensing

Solution Overview

Problem

Existing occupant information sensing devices for vehicle steering wheels require additional electrodes for functions like heartbeat detection and gripping state detection, complicating the structure and increasing manufacturing costs.

Innovation Solution

A device using a plurality of heater electrodes at the steering wheel, with a non-insulated AC power source and a filter to pass AC power while blocking occupant information signals, allowing for signal processing without an additional electrode, and incorporating a switching element for time division control to activate/deactivate functions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If additional electrodes are added for heartbeat detection and gripping state detection, then multiple functions can be implemented, but the structure becomes complicated and manufacturing cost increases

Engineering Contradiction:

Improvemultiple functionsVSAvoidstructure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The heater electrode is designed to perform multiple functions: it generates heat for the occupant while simultaneously serving as a sensing electrode for detecting biological information (heartbeat) and gripping state. This multi-functionality eliminates the need for separate electrodes, simplifying the overall structure while maintaining versatile capabilities.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the heater electrode and the sensing electrode into a single integrated component. The heater electrode structure is merged with the biological information sensing function, allowing both heating and detection operations to be performed through the same physical electrode without requiring additional separate components.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If additional electrodes are added for heartbeat detection and gripping state detection, then multiple functions can be implemented, but manufacturing cost increases

Engineering Contradiction:

Improvemultiple functionsVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The heater electrode is designed to perform multiple functions: it generates heat for the occupant while simultaneously serving as a sensing electrode for detecting biological information (heartbeat) and gripping state. This multi-functionality eliminates the need for separate electrodes, simplifying the overall structure while maintaining versatile capabilities.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the heater electrode and the sensing electrode into a single integrated component. The heater electrode structure is merged with the biological information sensing function, allowing both heating and detection operations to be performed through the same physical electrode without requiring additional separate components.

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If heater electrode is used for both heating and signal detection, then structure is simplified, but signal processing becomes difficult due to AC power interference

Engineering Contradiction:

ImprovestructureVSAvoidsignal processing

Core Design Contradiction:

Device complexityVSDifficulty of detecting and measuring

Solution Approach 1:

The harmful AC power interference signal is extracted and removed from the composite signal obtained from the heater electrode. A band-pass filter is used to extract and eliminate the AC power frequency component, separating it from the biological information signal so that only the useful biological information remains for further processing.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

A band-pass filter is introduced as an intermediary component between the heater electrode and the signal processing circuit. This filter acts as a mediator that selectively passes the biological information signal frequency while blocking the AC power interference frequency, enabling clean signal acquisition without requiring separate electrodes.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enables efficient processing of occupant information signals using heater electrodes, reducing complexity and manufacturing costs while maintaining multiple functional capabilities.

Implementation Method 1

a plurality of heater electrodes 106, 108 which are insulated and separated from one another and which generate heat by conduction

Methodology Applied

Scientific EffectConduction (thermal): Conduction (thermal)

Implementation Method 2

a filter 160a to 160d which blocks a frequency of an occupant information signal output from the heater electrode 106, 108

Methodology Applied

Scientific EffectFilter (electronic): Filter (electronic)

Data Source

PatentEP3345542B1Passenger information sensing device

Publication Date: 2022.06.08 AUTOLIV DEV AB

Figure 1(a)~1(b)
Figure 2(a)~2(b)
Figure 3

AI summary

An occupant information sensing device 100 includes a plurality of heater electrodes that are provided at a vehicle steering wheel 104 and insulated and separated from one another and that generate heat by conduction; first heater power sources 118a and 118b of an insulated type DC power source that feed power to at least two heater electrodes 106 and 108 of the plurality of heater electrodes; and a heartbeat detecting circuit 124 that is connected to the heater electrode through a capacitor 124a and processes heartbeat signals 136 and 138, which are occupant information signals output from the heater electrodes.