Refrigerator Dual Sensor Control for Ambient IR Interference Rejection
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Solution Overview
Problem
Conventional refrigerators face challenges with ambient conditions affecting the performance of sensors controlling interior lights and dispensers, such as IR sensors being overwhelmed by sunlight or incandescent light, leading to inaccurate activation.
Innovation Solution
A dual sensor system with at least two spaced apart sensors in operational communication with a controller, which senses timing differences in output signals to differentiate between operator movement and ambient changes, allowing for adaptive calibration and improved control of interior lights and dispensers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single IR sensor is used to control interior lights and dispensers, then the device can detect operator presence, but ambient IR sources like sunlight and incandescent light can blind or overwhelm the sensor, leading to inaccurate detection
Solution Approach 1:
The patent divides the sensing function into two separate sensors: a first sensor for detecting operator presence and a second sensor for detecting ambient light conditions. This segmentation allows each sensor to specialize in its specific detection task, with the second sensor specifically calibrated to filter out ambient IR interference from sources like sunlight and incandescent lighting, thereby maintaining reliable detection accuracy in challenging environmental conditions
Solution Approach 2:
The controller acts as an intermediary that receives signals from both sensors and processes them to determine whether to activate the interior light or dispenser. By comparing data from the first sensor (operator presence) and the second sensor (ambient light levels), the controller intelligently distinguishes between genuine operator presence and ambient IR sources, preventing false activation while ensuring reliable operation
2Measurement precision
If the sensor controller is confused by ambient conditions, then activation accuracy deteriorates, but adding a dual sensor system increases device complexity
Solution Approach 1:
The sensing system is segmented into two specialized sensors with distinct functions: the first sensor detects operator presence while the second sensor monitors ambient light conditions. This division of labor improves measurement precision by having each sensor optimized for its specific parameter, while the complexity increase is managed through integrated control logic that processes both sensor inputs
Solution Approach 2:
The dual sensor system provides multi-functionality by simultaneously detecting both operator presence and ambient light conditions. This universal sensing capability allows the system to make intelligent decisions about activation based on multiple factors, improving overall control accuracy while the shared control infrastructure minimizes the complexity overhead
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
Enhances the reliability and accuracy of sensor-controlled operations by distinguishing between operator-induced changes and ambient influences, ensuring proper activation of lights and dispensers without direct contact.
Implementation Method 1
the controller senses a timing difference between the output signals from the at least two sensors caused by the movement of the operator
Data Source
AI summary
A refrigerator includes: a cabinet defining a refrigeration compartment with an opening and a door pivotally connected with the cabinet; a see-through door with an interior light for illuminating the refrigeration compartment and/or a dispenser mounted in the door or in the cabinet for dispensing water and/or ice; and a sensor unit operatively associated with the interior light and/or the dispenser, the sensor unit including at least two spaced apart sensors in operational communication with a controller, each sensor producing an output signal, the controller senses a timing difference between the output signals from the at least two sensors caused by the movement of the operator to control dispensing, and the controller establishes a calibration setting based on the output signals of the sensor where ambient changes to the output signals are differentiated from the timing difference.