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 effectively sensing user inputs on metal or glass surfaces while preventing static electricity transfer and ensuring durability and ease of integration with display systems.
Innovation Solution
A touch sensor assembly comprising a sensor housing with a copper-coated PCB, a metal plate, ceramic element, spacer, conductive foil, and a touch booster, which senses user touches and transmits signals while minimizing static electricity interference and integrating seamlessly with display components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a touch sensor assembly is integrated into a metal or glass exterior member of a household appliance, then the user interface becomes more integrated and aesthetically pleasing, but static electricity transfer between the user and the appliance increases
Solution Approach 1:
A touchable layer is introduced as an intermediary between the user's finger and the conductive exterior member (metal or glass surface). This layer allows capacitive touch sensing while preventing direct electrical contact that would transfer static electricity to the user. The touchable layer acts as a mediator that enables touch functionality without the harmful static electricity transfer.
2Reliability
If a transparent touch screen is used to cover the display unit, then the display is protected and touch input is enabled, but the touch sensor becomes less sensitive to user touches
Solution Approach 1:
The touchable layer is designed with specific material properties (conductivity, thickness, elasticity) that optimize both protection and touch sensitivity. By carefully controlling these parameters, the layer provides adequate protection for the display while maintaining sufficient capacitive coupling between the user's finger and the sensor electrode below, ensuring accurate touch detection.
3Device complexity
If the touch sensor assembly is directly mounted on the exterior member, then the structure is simplified, but the sensor is vulnerable to damage from environmental factors and improper installation
Solution Approach 1:
The touch sensor assembly is nested within a housing structure that is integrated with or attached to the exterior member. The housing protects the sensor components (sensor electrode, touchable layer, adhesive layer) from environmental factors and mechanical damage, while still allowing capacitive touch input through the exterior member surface. This nested structure provides protection without significantly increasing overall complexity.
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 provides reliable touch input detection, reduces static electricity risks, and enhances the durability and integration of touch sensor systems with display units on metal or glass surfaces, improving user interaction and appliance control.
Implementation Method 1
touch sensor assemblies are used for household appliances and may include electrostatic capacitance sensors or sensors using a resistance cell, etc. Such sensors sense a user's touches
Implementation Method 2
a sensor PCB which is provided inside the sensor housing and has a top surface on which a copper coating or film is formed
Data Source
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AI summary
A touch sensor assembly (500) may include a sensor housing (500a) disposed at a bottom surface of an exterior member of a household appliance in which an operation unit (12) on which a user touches is formed; a sensor PCB (700) which is provided inside the sensor housing (500a) and has a top surface on which a copper coating or film (712) is formed; a touch sensor (750), the touch sensor (750) including: a metal plate (751) having a bottom surface in contact with the copper coating or film (712); and a ceramic element (752) installed on a top surface of the metal plate (751); a spacer (730) in which a sensor hole (731) is formed at a position corresponding to the sensor (750) and which has a bottom surface attached to a surface of the copper coating or film (712); a conductive foil (740) attached to a top surface of the spacer (730) and having a bottom surface on which an inner guide line (742) which applies an electric current to the ceramic element (752) and an outer guide line (743) which applies an electric current to the metal plate (751) are printed; and a contact portion (745; 746) formed to protrude from a top surface of the conductive foil (740) corresponding to a position of the inner guide line (742).