Infrared Sensor Array Thermal Compensation
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Solution Overview
Problem
Infrared sensor arrays face non-uniformity issues due to parasitic thermal fluxes and thermal gradients, leading to inaccurate temperature measurements and image recognition, as each pixel responds differently to the same radiation due to varying temperatures and thermal resistance.
Innovation Solution
Incorporating a sensor array with both infrared sensing elements (LIVE pixels) and compensation elements, where the compensation elements are designed to absorb less radiation, allowing for a subtractive function of their signals to compensate for parasitic thermal effects, thereby stabilizing the thermal environment and improving radiation detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor array is used to detect infrared radiation, then the ability to measure temperature and provide images is improved, but non-uniformity between pixels occurs due to parasitic thermal fluxes and thermal gradients
Solution Approach 1:
The patent introduces compensation pixels as intermediary elements that do not directly detect the target infrared radiation but instead measure parasitic thermal fluxes. These compensation pixels act as mediators between the thermal environment and the sensing pixels, allowing the system to separate and compensate for unwanted thermal effects from the actual radiation measurements.
Solution Approach 2:
The system implements a feedback mechanism where compensation pixels continuously measure thermal gradients and parasitic fluxes, and this information is used to adjust and correct the readings from the sensing pixels. This closed-loop approach allows real-time compensation for thermal effects, maintaining measurement accuracy despite varying thermal conditions.
2Measurement precision
If correction factors are applied to compensate for pixel non-uniformity, then image quality is improved, but the correction factors become sensitive to array temperature variations
Solution Approach 1:
The system performs preliminary measurements using compensation pixels to characterize the thermal environment before the actual sensing pixels take measurements. By pre-measuring parasitic thermal fluxes and thermal gradients, the system can establish baseline correction data that adapts to current temperature conditions, making the correction process more robust to temperature variations.
Solution Approach 2:
The compensation pixels are designed as copies of the sensing pixels but with modified optical properties (blocked aperture) that prevent them from detecting target radiation while maintaining identical thermal coupling. This copying approach ensures that compensation pixels experience the same thermal environment as sensing pixels, allowing accurate measurement of parasitic effects for subsequent correction.
3Measurement precision
If dedicated temperature sensors are added to measure array temperature, then temperature compensation is improved, but the extreme sensitivity of correction factors to temperature makes accurate measurement difficult
Solution Approach 1:
The compensation pixels serve multiple functions: they act as both thermal environment sensors and reference elements for radiation measurement calibration. By making the compensation pixels multi-functional, the system eliminates the need for separate dedicated temperature sensors, reducing overall system complexity while maintaining accurate temperature compensation capability.
Solution Approach 2:
The system uses its own pixel structure to perform temperature measurement and compensation rather than requiring external temperature sensors. The compensation pixels self-service by measuring the thermal conditions that affect all pixels, and this self-measured data is used to correct the readings, making the system self-sufficient for temperature compensation.
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 effectively compensates for linear and non-linear thermal gradients, ensuring accurate detection of infrared radiation and reducing signal distortion, allowing for precise temperature measurement and image processing.
Implementation Method 1
each infrared sensing element having a radiation responsive element providing a proportionate electrical signal in response to infrared radiation incident thereto
Implementation Method 2
radiation responsive element providing a proportionate electrical signal in response to infrared radiation incident thereto
Implementation Method 3
IR sensors are used to measure temperatures and/or provide images of remote objects in a scene by detecting the infrared radiation emitted from the target object
Data Source
AI summary
An infrared sensor assembly for sensing infrared radiation comprises infrared sensing elements and the infrared sensing compensation elements that are different so that, for a same flux on the infrared sensing elements and the infrared sensing compensation elements, the radiation responsive element of the infrared sensing elements absorbs more radiation than the radiation responsive element of the infrared sensing compensation elements, as to receive substantially more radiation than the radiation responsive element of the infrared sensing compensation elements. An output of the sensor array is a subtractive function of a sum of the signals of the plurality of infrared sensing elements and a sum of the signals of the plurality of the infrared sensing compensation elements such that at least linear and/or non-linear parasitic thermal fluxes are at least partly compensated for.