Hand dryer device
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Solution Overview
Problem
In hand drying apparatuses with multiple capacitance-detection-type proximity sensors, the simultaneous operation of detection electrodes leads to interference, reducing detection accuracy as the capacitance generated by one electrode affects the other, making it difficult to distinguish hand insertion capacitance from electrode energization capacitance.
Innovation Solution
The hand drying apparatus controls the operation of capacitance-detection-type sensors such that only one sensor is active at a time, ensuring that detection electrodes are energized at different timings to prevent mutual interference, thereby improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple capacitance-detection-type sensors operate simultaneously, then the detection coverage is improved, but the detection accuracy deteriorates due to mutual interference between electrodes
Solution Approach 1:
The patent implements periodic action by sequentially activating capacitance-detection-type sensors at different time intervals rather than simultaneously. The control unit switches each sensor on and off in a time-division manner, allowing each sensor to detect capacitance changes during its active period without interference from other sensors. This temporal separation resolves the contradiction by maintaining multi-sensor coverage while eliminating mutual interference that degrades detection accuracy.
2Duration of action of stationary object
If multiple detection electrodes are energized simultaneously, then the sensor operation is continuous, but the capacitance measurement becomes unreliable due to cross-interference
Solution Approach 1:
The control unit implements periodic action by sequentially energizing detection electrodes in time-division multiplexing mode. Each electrode is activated for a specific time period, then deactivated before the next electrode is energized. This ensures that capacitance measurements taken during each electrode's active period are not contaminated by the electric fields of other electrodes, thereby maintaining measurement reliability while preserving overall sensor system operation continuity through the sequential activation pattern.
3Adaptability or versatility
If capacitance-detection-type sensors are used in a hand dryer, then the hand detection function is achieved, but the detection precision decreases when multiple sensors operate at the same time
Solution Approach 1:
The patent applies periodic action by implementing time-division multiplexing control for multiple capacitance-detection-type sensors in the hand dryer. The control unit sequentially activates each sensor to detect hand presence in the hand insertion portion during its designated time slot. This approach maintains the versatility of having multiple sensors for comprehensive hand detection coverage while eliminating mutual interference through temporal separation, thereby preserving detection precision that would otherwise be degraded by simultaneous operation.
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
This approach enhances the detection accuracy of each capacitance-detection-type sensor by preventing cross-interference, allowing for precise hand detection without the influence of other electrodes' energization, thus improving overall hand detection reliability.
Implementation Method 1
capacitance-detection-type sensors (which are also referred to as capacitance-detection-type proximity sensors) detect the approach of objects (objects to be detected) by measuring the change in capacitance that occurs due to the presence of human bodies or the like
Data Source
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AI summary
A hand dryer (10) that includes a capacitance-detection-type proximity sensor structure (1) that detects a capacitance generated in a capacitance detection electrode to detect a presence or absence of an object to be detected, includes a plurality of capacitance-detection-type proximity sensor structures (1). While one of the capacitance-detection-type proximity sensor structures (1) is in operation, an operation of at least another of the capacitance-detection-type proximity sensor structures (1) is stopped to operate the capacitance-detection-type proximity sensor structures (1) during different periods of time.