Infrared Thermometer Capacitive Distance Shielding
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Solution Overview
Problem
Conventional infrared thermometers face challenges in accurately measuring temperature due to the influence of capacitance from unwanted objects and surfaces, leading to incorrect distance determination and activation of the infrared sensor, especially when used by hand or near conductive materials.
Innovation Solution
The infrared thermometer incorporates a first conductor for distance determination and a second conductor as a shield to reduce interference from unwanted objects, with a microcontroller activating or deactivating the sensor based on capacitance signals, preventing incorrect activation and improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a distance sensor is used to determine distance by measuring capacitance value, then the infrared sensor can be activated automatically at appropriate distance, but the capacitance value is affected by nearby conductors causing wrong activation and incorrect temperature measurement
Solution Approach 1:
The patent introduces a shield conductor as an intermediary element positioned between the distance sensor and external conductive objects. This shield conductor mediates the capacitive field interactions by providing a reference plane that isolates the distance sensor from spurious capacitance effects of nearby conductors, enabling accurate distance measurement while maintaining automatic activation capability
Solution Approach 2:
The patent extracts and separates the shield conductor function from the distance sensing function. By dedicating a specific conductor (the shield) solely to providing a reference capacitive plane, it removes the interference of external conductors from the distance measurement process, allowing the distance sensor to operate independently and accurately
2Ease of operation
If the operator's hand is too close to the head of the infrared thermometer, then the basis capacitance value of the distance sensor changes, but this causes the capacitance value measured by the distance sensor to be unsuitable for accurately determining distance
Solution Approach 1:
The shield conductor acts as an intermediary that isolates the distance sensor from the operator's hand capacitance. By positioning the shield between the sensor and the hand, it prevents the hand's capacitance from directly affecting the distance measurement, allowing flexible handheld operation without compromising measurement accuracy
Solution Approach 2:
The shield conductor provides preliminary protection against capacitance interference from the operator's hand before the measurement process occurs. By establishing a reference capacitive plane in advance, it preemptively counteracts the potential interference that would otherwise occur during 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 design enhances measurement accuracy by accurately determining the distance to the object and preventing false activation, thereby ensuring precise temperature measurement, even when used near conductive surfaces or objects.
Implementation Method 1
a first conductor (115) arranged on the housing (111) and configured to determine a distance between the head (11) and a surface of an object to be measured when the surface of the object to be measured is approaching to the head (11)
Implementation Method 2
a second conductor (116) arranged between the first conductor (115) and the handheld part (12) and adjacent to the holder (114)... configured to reduce the interference to the first conductor (115) when any object not desirable to be measured is approaching to the head (11)
Implementation Method 3
an infrared sensor configured to measure the temperature of an object to be measured
Data Source
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AI summary
An infrared thermometer (10), comprising a handheld part (12) and a head (11) connected to the handheld part (12). The head (11) comprises a bottom shell (112); an infrared sensor (113) configured to measure the temperature of an object to be measured; a holder (114) configured to hold the infrared sensor (113) in the bottom shell (112); a housing (111) configured to accommodate the infrared sensor (113) and the holder (114), and combined with the bottom shell (112); a first conductor (115) arranged on the housing (111); and a second conductor (116) arranged between the first conductor (115) and the handheld part (12) and adjacent to the holder (114) wherein the first conductor (115) and the second conductor (116) are capacitive sensors.