Refrigerator including touch sensor
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Solution Overview
Problem
Resistive touch interfaces in refrigerators often struggle to accurately sense both push and release operations due to low-level input signal voltages, leading to insufficient sensing speed and response speed for user interactions.
Innovation Solution
An amplification circuit is employed to enhance the input signal from the touch sensor, with a sensor controller determining push and release operations based on threshold voltage values, and a reference voltage is output when no signal is received, allowing for precise differentiation between these operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a resistive touch interface is used in the refrigerator door, then the manufacturing cost is reduced and aesthetics are improved, but the input signal voltage level becomes too low to accurately sense touch operations
Solution Approach 1:
An amplification circuit is introduced as an intermediary component between the resistive touch sensor and the controller. This amplifier boosts the low-level input signals from the touch sensor to a level that can be accurately detected and processed by the controller, resolving the contradiction between using low-cost resistive touch interfaces and achieving sufficient signal detection accuracy.
2Device complexity
If only one of push or release operation is sensed in resistive touch interfaces, then the device complexity is reduced, but the sensing speed and response speed become insufficient
Solution Approach 1:
The system dynamically responds to both push and release operations by implementing bidirectional threshold detection. The controller monitors signal transitions in both directions (increasing and decreasing voltage levels), enabling it to detect and respond to both push and release operations. This dynamic approach improves sensing and response speed without requiring separate sensing mechanisms for each operation type.
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 increases the sensitivity of the touch sensor, enabling more precise control and faster response times by accurately sensing both push and release operations, improving user interaction with the refrigerator.
Implementation Method 1
resistive touch interfaces driven by sensing a pressure applied to a sensor
Data Source
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AI summary
A refrigerator includes a door (10) that has a front panel (20) with an operation area to receive a touch operation of a user, a touch sensor assembly (500) that is located rearward of the operation area and that includes sensors (750) to generate an input signal based on the touch operation, and a sensor controller (314) connected to the touch sensor assembly (500) and configured to process the input signal received from the touch sensor assembly (500). The sensor controller (314) is configured to determine whether the touch operation is a push operation or a release operation based on comparison of a voltage value of the processed input signal to predetermined first and second threshold voltage values.