Non-contact Temperature Sensor With Thermo-optical Shield
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Solution Overview
Problem
Thermopile sensors face challenges in accurately measuring object temperatures due to interference from electromagnetic radiation and temperature gradients within the sensor package, leading to errors in temperature readings.
Innovation Solution
A sensor package is designed with a thermopile sensor and a reference thermopile sensor, along with a thermo-optical shield that blocks electromagnetic radiation and isolates the thermopile sensors from temperature variations, using a transparent structure and an electromagnetic blocker to prevent radiation from reaching the reference thermopile sensor and mitigate temperature gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference thermopile sensor is added to block electromagnetic radiation, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The sensor package is divided into two functional segments: a measurement thermopile sensor for detecting target temperature and a reference thermopile sensor for detecting electromagnetic radiation interference. Each segment serves a specific function, allowing the system to differentiate between actual temperature signals and interference signals through differential measurement.
Solution Approach 2:
A differential processing mechanism acts as an intermediary between the two thermopile sensors. This intermediary processes the output signals from both sensors, subtracting the reference signal from the measurement signal to eliminate electromagnetic radiation interference and extract the true temperature information.
2Measurement precision
If a thermo-optical shield is introduced to block radiation, then measurement precision is improved, but manufacturing precision requirements increase
Solution Approach 1:
The thermo-optical shield is designed with selective optical properties: it is opaque to electromagnetic radiation in the measurement wavelength range to block interference, while being transparent to infrared radiation at thermal wavelengths to allow actual temperature measurement. This local quality differentiation enables the shield to perform multiple functions with a single component.
Solution Approach 2:
The shield structure combines materials with different optical transmission properties to create a composite component that selectively blocks certain wavelengths while transmitting others. This composite approach allows the shield to provide both protection against interference and transparency for measurement without requiring perfect positioning accuracy.
3Measurement precision
If multiple thermopile sensors are used to filter interference, then measurement precision is improved, but loss of energy increases
Solution Approach 1:
The reference thermopile sensor serves itself by detecting the electromagnetic radiation interference that also affects the measurement sensor. By using the same sensor type and measurement principle for both reference and measurement, the system achieves self-calibration and automatic interference compensation without requiring additional energy-intensive active cooling or heating systems.
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 configuration enhances the accuracy of temperature measurements by reducing noise and errors caused by electromagnetic interference and temperature gradients, allowing for precise non-contact temperature measurement.
Implementation Method 1
Thermopile sensors convert thermal energy into electrical energy. These sensors may utilize several thermocouples to generate an output voltage proportional to a local temperature difference
Implementation Method 2
The lid assembly includes a transparent structure that passes electromagnetic radiation occurring in a limited spectrum of wavelengths (e.g., infrared radiation [IR])
Implementation Method 3
The thermo-optical shield is configured to at least substantially block the electromagnetic radiation occurring in a limited spectrum of wavelengths from reaching the reference thermopile sensor
Data Source
AI summary
The present disclosure is directed to a sensor package having a thermopile sensor and a reference (or dark channel) thermopile sensor disposed therein for temperature measurements. In one or more implementations, the sensor package includes a substrate, a thermopile sensor disposed over the substrate, a reference thermopile sensor disposed over the substrate, a reference temperature sensor disposed over the substrate surface, a lid assembly disposed over the thermopile sensor and the reference thermopile sensor, and a thermo-optical shield. The thermo-optical shield defines an aperture over the thermopile sensor such that at least a portion of the thermo-optical shield is positioned over the reference thermopile sensor to provide optical and thermal shielding for portions of the sensor package.