Infrared Temperature Sensor with Segmented Light Shielding
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Solution Overview
Problem
Conventional infrared temperature sensors face challenges in accurately detecting surface temperatures under severe conditions, such as high temperatures and rapid temperature changes, due to heat conduction and convection effects from the object being measured, leading to errors in temperature compensation.
Innovation Solution
An infrared temperature sensor design featuring a metal sensor case with a light guiding region and a light shielding region, where a film absorbs infrared rays and converts them to heat, allowing the infrared detection element and temperature compensation element to receive equivalent heat energy except for radiation, enabling accurate detection of heat energy by difference, and using an infrared absorption molded body to reduce costs and improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the infrared temperature sensor is arranged adjacent to the roller for temperature detection, then the temperature can be detected in a non-contact manner, but the sensor is susceptible to heat conduction and convection from the roller causing temperature compensation errors
Solution Approach 1:
The sensor housing is divided into a light guiding region and a light shielding region through a partition wall. The light guiding region allows infrared rays from the roller to reach the detection element, while the light shielding region blocks direct heat conduction and convection paths to the temperature compensation element, isolating thermal influences while maintaining optical detection capability.
Solution Approach 2:
The temperature compensation element is extracted from the direct thermal influence zone by positioning it in the light shielding region, separated from the roller by the partition wall. This extraction removes the harmful thermal conduction and convection effects from the compensation path while the detection element remains in the light guiding region to capture infrared radiation.
2Speed
If the sensor measures rapid temperature changes of the roller, then real-time temperature control is achieved, but the temperature compensation element cannot accurately detect the sensor's own temperature due to rapid thermal changes
Solution Approach 1:
The partition wall creates separate thermal zones for the detection element and temperature compensation element. The compensation element in the shielded region experiences delayed and attenuated thermal changes compared to the detection element, allowing it to accurately sense the sensor housing's baseline temperature even during rapid roller temperature transitions.
Solution Approach 2:
The partition wall acts as a thermal intermediary that transmits minimal heat to the compensation element while allowing optical detection to proceed. This intermediary structure protects the compensation element from rapid thermal transients, enabling it to maintain accurate temperature sensing during dynamic operating conditions.
3Device complexity
If conventional infrared temperature sensors are used without light shielding, then the structure is simple, but the temperature compensation accuracy is lowered due to heat influence from the object being detected
Solution Approach 1:
The housing is segmented into functional regions using a partition wall that creates distinct optical and thermal zones. This segmentation adds minimal structural complexity while effectively blocking thermal conduction and convection paths to the compensation element, significantly improving temperature compensation accuracy.
Solution Approach 2:
The partition wall provides localized thermal shielding precisely where needed - around the temperature compensation element in the light shielding region. This localized quality enhancement targets the specific problem area without requiring complete redesign of the entire sensor structure, achieving improved compensation accuracy with moderate complexity increase.
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
The sensor accurately measures surface temperatures even under severe conditions by isolating heat influences, reducing errors, and lowering production costs through the use of an infrared absorption molded body and variable resistance detection circuit.
Implementation Method 1
a film is arranged opposing the light guiding region and the light shielding region. The film absorbs the infrared rays that reach the film through the light guiding region, and converts the infrared rays to heat.
Implementation Method 2
the infrared detection element detects a heat emission amount of infrared rays from the roller as the fixing means that is an object to be detected
Implementation Method 3
the temperature compensation element further detects an atmosphere temperature to perform temperature compensation
Implementation Method 4
The light guiding region guides infrared rays entering from an entrance window
Implementation Method 5
a shielding wall that blocks entrance of the infrared rays is formed on an entrance side of the infrared rays
Data Source
Figure 1A~1E
Figure 2A~2B
Figure 3A~3B
AI summary
To provide an infrared temperature sensor which can accurately measure a surface temperature of an object to be detected even under a severe temperature detection environment. An infrared temperature sensor including: a sensor case 10 including a first airspace 53 (a light guiding region) that guides infrared rays entering from an infrared entrance window 26, and a second airspace (a light shielding region) that is adjacent to the light guiding region via a partition wall 52, and where an upper wall 24 that blocks entrance of the infrared rays is formed on an entrance side of the infrared rays; a film 40 that absorbs the infrared rays reaching the film through the light guiding region, and converts the infrared rays to heat; a sensor cover 30 that is arranged opposing the sensor case 20 via the film 40; an infrared detection element 43 and a temperature compensation element 45 arranged on the film 40, wherein the light guiding region and the light shielding region have substantially symmetrical forms with respect to the partition wall 52.