Refrigerator Touch Sensor with Dual-Mode Panel Material Detection
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Solution Overview
Problem
Existing home appliances face challenges in accurately detecting user inputs on touch panels made of different materials, such as metal, glass, or plastic, due to the limitations of capacitive and inductive sensing methods, which often fail to function effectively across various panel types.
Innovation Solution
A refrigerator is equipped with a printed circuit board (PCB) that includes a pattern coil functioning as both an inductive and capacitive sensor, coupled with a touch integrated circuit (IC) to identify the panel material and adjust sensing methods accordingly, allowing for seamless touch detection regardless of panel material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If capacitive sensing method is used for touch detection, then it works well on non-conductive panels (glass, plastic), but it fails to function effectively on conductive panels (metal)
Solution Approach 1:
The pattern coil is designed to perform multiple functions: it serves as an inductive sensor for conductive panels and as a capacitive sensor for non-conductive panels. The touch IC automatically identifies the panel type and switches between sensing methods, making the touch detection system universally compatible with different panel materials without requiring separate sensor systems.
Solution Approach 2:
The sensing method dynamically adapts based on panel material identification. The touch IC determines whether the panel is conductive or non-conductive and switches the pattern coil's operating mode accordingly - using inductive sensing for metal panels and capacitive sensing for glass or plastic panels, ensuring reliable touch detection across all panel types.
2Reliability
If inductive sensing method is used for touch detection, then it works well on conductive panels (metal), but it fails to function effectively on non-conductive panels (glass, plastic)
Solution Approach 1:
The pattern coil is designed to perform multiple functions: it serves as an inductive sensor for conductive panels and as a capacitive sensor for non-conductive panels. The touch IC automatically identifies the panel type and switches between sensing methods, making the touch detection system universally compatible with different panel materials without requiring separate sensor systems.
Solution Approach 2:
The sensing method dynamically adapts based on panel material identification. The touch IC determines whether the panel is conductive or non-conductive and switches the pattern coil's operating mode accordingly - using inductive sensing for metal panels and capacitive sensing for glass or plastic panels, ensuring reliable touch detection across all panel types.
3Reliability
If separate sensor systems are used for different panel materials, then each sensor works optimally for its designated panel type, but the device complexity increases
Solution Approach 1:
The pattern coil is designed to perform multiple functions: it serves as an inductive sensor for conductive panels and as a capacitive sensor for non-conductive panels. The touch IC automatically identifies the panel type and switches between sensing methods, making the touch detection system universally compatible with different panel materials without requiring separate sensor systems.
Solution Approach 2:
The inductive sensing capability and capacitive sensing capability are merged into a single integrated system. The pattern coil and touch IC combination provides both sensing methods in one unified structure, eliminating the need for separate sensor systems while maintaining optimal performance for different panel types.
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 reliable touch detection and automatic door operation based on user input, irrespective of the panel's conductive or non-conductive nature, enhancing user interaction and design flexibility.
Implementation Method 1
a touch integrated circuit (IC) configured to, based on the panel being displaced in the first direction by a user's touch, process the user's touch by inductive sensing according to a change of a magnetic field at the pattern coil
Implementation Method 2
based on the panel being identified as a non-conductive panel, process the user's touch by capacitive sensing
Data Source
AI summary
A refrigerator including a cool air supply device configured to supply cool air; a storage room configured to receive the supplied cool air so that food is storable in the storage room at a low temperature; a door configured to open and close the storage room, and to insulate the storage room from outside temperature; a panel on the door and configured to, based on a user touching the panel, be displaced in a first direction; and a printed circuit board (PCB) behind the panel, the PCB including a pattern coil facing the first direction and configured to function as an inductive sensor, and a touch integrated circuit (IC) configured to, based on the panel being displaced in the first direction by a user's touch, process the user's touch by inductive sensing according to a change of a magnetic field at the pattern coil.