Touch sensor assembly and door including the same

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Solution Overview

Problem

Existing touch sensor assemblies for household appliances, such as refrigerators, face challenges in accurately sensing touch movements and maintaining recognition rates due to inadequate support structures and sensitivity issues, particularly when integrated into exterior members like stainless steel or glass surfaces.

Innovation Solution

A touch sensor assembly with a sensor housing and elastic member that presses a sensor PCB against the exterior member, supported by a sensor support portion, enhancing sensitivity by concentrating force at the center and preventing inclination, while the elastic member is fixed using press-fitting to avoid sensitivity failures and static electricity damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the touch sensor assembly is mounted without adequate support structure, then the device complexity is reduced, but the measurement precision of touch movement decreases

Engineering Contradiction:
Improvetouch movement sensing accuracyVSAvoidsupport structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A sensor support portion is introduced as an intermediary component between the sensor PCB and the exterior member. This support structure concentrates the pressing force at the center of the touch sensor, improving touch movement sensing accuracy without requiring complex overall support structures.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The sensor support portion provides localized support specifically at the center region of the touch sensor, rather than uniform support across the entire sensor assembly. This localized quality enhancement improves measurement precision where it is most needed while minimizing additional complexity.

Inventive Principle:
Principle #3Local quality

2Reliability

If the sensor PCB is not pressed against the exterior member, then the device complexity is reduced, but the reliability of touch recognition decreases

Engineering Contradiction:
Improvetouch recognition rateVSAvoidpressing mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sensor PCB utilizes the exterior member itself as the pressing mechanism. The exterior member's natural rigidity and structure provide the necessary pressing force, eliminating the need for separate active pressing mechanisms while maintaining reliable touch recognition.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The sensor support portion acts as an intermediary that translates the exterior member's structural properties into effective pressing force on the sensor PCB, ensuring reliable contact without requiring complex pressing mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If adhesive is used to fix the elastic member, then the ease of manufacture is improved, but the reliability of sensor contact decreases due to sensitivity failures

Engineering Contradiction:
Improveelastic member installation easeVSAvoidsensor contact stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The chemical bonding method (adhesive) is replaced with a mechanical bonding method (press-fitting). The elastic member is fixed to the sensor PCB through precise mechanical interference fit, providing reliable sensor contact while maintaining ease of manufacture through standardized mechanical assembly processes.

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

4Ease of manufacture

If the touch sensor is exposed to static electricity during manufacturing, then the manufacturing process is simplified, but the reliability of the sensor decreases due to damage

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidstatic electricity damage
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The sensor PCB is mounted on the elastic member before the door assembly manufacturing process begins. This timing arrangement cushions the sensitive sensor from static electricity generation during the foam injection and assembly processes, preventing damage while maintaining manufacturing simplicity.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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

The solution improves touch recognition accuracy and sensitivity by maintaining the sensor's pressed state against the exterior member, preventing inclination, and reducing the risk of sensitivity failures and static electricity damage, thus enhancing the overall touch recognition rate and structural integrity.

Implementation Method 1

an elastic member which is disposed at the rear of the sensor PCB and presses the sensor PCB toward a rear surface of the external member

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3664296B1Touch sensor assembly and door including the same
Publication Date: 2021.06.23 LG ELECTRONICS INC
  • EP3664296B1 patent drawingFigure 1
  • EP3664296B1 patent drawingFigure 2
  • EP3664296B1 patent drawingFigure 3

AI summary

A touch sensor assembly (500) according to an embodiment of the present disclosure includes a sensor housing (500a) disposed at a rear surface of an external member (10) on which a touch operation unit on which a user touches is marked, a sensor PCB (700) accommodated in the sensor housing (500a), and an elastic member (720) which is disposed at a rear side of the sensor PCB (700) and presses the sensor PCB (700) toward a rear surface of the external member (10), wherein the elastic member (720) is mounted in an elastic member accommodation portion (526) formed at a bottom surface of the sensor housing (500a).