Automotive Smart Garnish Capacitive Sensor Noise Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional smart garnishes for automobiles face issues with touch sensor malfunctions due to unwanted symbol interactions, mechanical force sensor complexity, and instability in capacitive touch and force sensing, especially in injection-molded products with curved surfaces and varying thicknesses, leading to high noise and malfunction risks.

Innovation Solution

A smart garnish design featuring a capacitive touch sensor pad and a capacitive force sensor pad with a gap between them, where capacitive touch sensors are aligned with symbols and capacitive force sensors are distributed corresponding to the ground, combined with a haptic actuator and restoring springs, and a diffusion sheet to prevent light leakage, ensuring accurate and stable sensing on 3D curved surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional touch sensors and mechanical force sensors are used in smart garnish, then touch and force sensing functions are provided, but malfunction occurs when unwanted symbols are touched or when cumulative tolerances cause air pressing

Engineering Contradiction:

Improvesensor operation reliabilityVSAvoidnoise and malfunction

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The sensing function is segmented into multiple capacitive sensors (touch sensors and force sensors) distributed across different regions. Each sensor independently detects local capacitance changes, allowing the system to distinguish between intentional symbol presses and unintentional touches or air pressing, thereby reducing false malfunctions

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The conventional mechanical force sensor is replaced with a capacitive force sensor that detects force through capacitance changes rather than mechanical pressing. This substitution eliminates the need for physical pressing protrusions and reduces sensitivity to cumulative tolerances and air pressing, improving reliability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If mechanical force sensors are installed for each symbol to detect pressing force, then force sensing accuracy is improved, but device complexity increases significantly

Engineering Contradiction:

Improveforce sensing accuracyVSAvoidsensor configuration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Capacitive sensors serve multiple functions: they can detect both touch (presence) and force (pressure magnitude) by analyzing capacitance changes. This universal sensing mechanism eliminates the need for separate mechanical force sensors for each symbol, reducing device complexity while maintaining measurement precision

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses parameter changes in capacitance value to differentiate between touch and force conditions. By monitoring both the presence and magnitude of capacitance changes, the system achieves accurate force sensing without requiring complex mechanical sensor configurations for each symbol

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If capacitive touch sensors and force sensors are disposed corresponding to symbols in injection-molded garnish with curved surfaces, then touch and force sensing are provided, but noise increases due to wide pressed portions and varying thicknesses

Engineering Contradiction:

Improvetouch and force sensing capabilityVSAvoidsensing accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

Multiple capacitive sensors are segmented and distributed across different positions corresponding to symbols. Each sensor independently monitors its local region, allowing the system to identify the specific pressed symbol even when the pressed portion is wide, thereby reducing noise from surrounding areas

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each capacitive sensor is positioned to detect local capacitance changes at its specific location. The system analyzes the spatial distribution of capacitance changes across multiple sensors to identify the pressed symbol, making the sensing accurate despite varying thicknesses and curved surfaces of the injection-molded garnish

Inventive Principle:

Principle #3Local quality

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

This design provides reliable and sensitive capacitive force sensing with reduced noise, accurate operation, and improved emotional quality through tactile feedback, while minimizing LED light leakage and optimizing illuminance.

Implementation Method 1

a capacitive touch sensor and a capacitive force sensor which sense a touch and a pressing force of a finger by a change in capacitance

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS11498422B2Smart garnish for automobile

Publication Date: 2022.11.15 SEOYON E HWA CO LTD

AI summary

Provided is a smart garnish installed on an automobile interior material (a door trim, an instrument panel, a console, or the like), and to a smart garnish for an automobile which is driven when a capacitance change is sensed by a pressed deformation of an upper case through a capacitive touch sensor pad formed of a ground (GND) and capacitive touch sensors corresponding to symbols and capacitive force sensors distributed corresponding to the ground and thus the touch and force of the desired symbol are sensed without noise.