Pinhole Mask Single-Pixel IR Sensor for Precise Spot Temperature Measurement
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Solution Overview
Problem
Current non-contact temperature measurement technologies, such as infrared cameras, are costly and lack precision for measuring temperatures at small, focused areas like laser spots, making it difficult to achieve accurate process control in manufacturing processes like welding and 3D printing.
Innovation Solution
A method and system using a single-pixel IR sensing device with a pinhole mask and imaging optics to selectively measure thermal radiation from a small spot, allowing for precise temperature measurement without the need for expensive thermal imagers, enabling spot sizes as small as 0.1 mm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If infrared cameras are used for temperature measurement, then measurement coverage is improved, but cost increases significantly
Solution Approach 1:
The patent segments the measurement function by using a pinhole mask to divide the field of view into discrete measurement spots. Instead of using an expensive full-array infrared camera, the system uses a single-pixel detector combined with a pinhole mask to selectively measure temperature at specific locations, achieving spot measurement capability at much lower cost.
Solution Approach 2:
The patent creates an optical copy of the target area through the pinhole mask onto the single-pixel detector. By projecting the thermal radiation from specific spots through the pinhole aperture, the system replicates the measurement capability of expensive infrared cameras using inexpensive components.
2Ease of manufacture
If single-pixel IR sensors are used, then cost is reduced, but measurement precision deteriorates due to large focal spot size
Solution Approach 1:
The patent introduces a pinhole mask as an intermediary optical element between the target and the single-pixel detector. This pinhole aperture acts as a spatial filter that defines the measurement spot size, enabling precise spot measurement with a single-pixel sensor by blocking out-of-spot thermal radiation while allowing in-spot radiation to pass through.
3Device complexity
If conventional IR sensors are used, then device complexity is reduced, but measurement precision deteriorates for small spots
Solution Approach 1:
The pinhole mask serves as a simple yet effective intermediary that enhances measurement precision without adding complex optics. By placing a small aperture in the optical path, the system achieves precise spot selection and measurement capability while maintaining overall device simplicity and avoiding complex lens 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 approach provides cost-effective, high-precision non-contact temperature measurement, enabling single-point measurements comparable to thermal imagers at a significantly lower cost and overcoming the limitations of current single-point infrared sensors.
Implementation Method 1
measure a thermal radiation strength of the light rays corresponding to the image spot
Implementation Method 2
select an image spot in the image plane corresponding to the target spot to allow light rays of the thermal image corresponding to the image spot to pass through
Data Source
AI summary
A method, which is applied for non-contact temperature measurement of a spot on a target object, includes the following steps: image a thermal image of a target area on the target object and projecting the thermal image to an image plane; select an image spot in the image plane corresponding to the spot to allow corresponding light rays to pass through, while blocking all the rest of the light rays; measure a thermal radiation strength of the corresponding to light rays; and determine a temperature from the measured thermal radiation strength according to a calibration relation. A system of performing the above method is also provided.