Thermal Sensor Module Lens Array Motion Detection
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Solution Overview
Problem
Conventional motion detectors using pyroelectric materials cannot detect the presence or absence of a motionless warm object, as they generate signals only when heat flux changes, making it impossible to distinguish between moving and stationary individuals.
Innovation Solution
A thermal sensor module with a lens array that produces a direct current output proportional to the thermal energy received, utilizing multiple lenses to create alternating regions of high and low output signals, allowing for the detection of presence and motion by assessing changes in thermal energy across different zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If pyroelectric materials are used to detect motion, then motion detection capability is improved, but the ability to detect stationary objects deteriorates
Solution Approach 1:
The field of view is divided into multiple zones using a lens array, with each lens directing thermal energy from a specific zone to a corresponding thermal sensing device. This segmentation allows the system to detect both motion (by comparing signals across zones) and stationary objects (by detecting sustained thermal energy in specific zones), resolving the contradiction between motion detection capability and stationary object detection reliability.
2Productivity
If pyroelectric detectors are used, then signal generation upon heat flux change is improved, but continuous presence detection deteriorates
Solution Approach 1:
The patent employs thermal sensing devices that produce a sustained direct current output proportional to the continuous thermal energy received from stationary objects. This continuous output signal enables reliable detection of presence over time, addressing the limitation of pyroelectric detectors that only generate transient signals during heat flux changes.
3Measurement precision
If a lens array is introduced to create multiple output regions, then detection precision is improved, but device complexity increases
Solution Approach 1:
The patent integrates the lens array directly with the thermal sensing devices in a unified optical assembly, where multiple lenses are arranged in an array configuration that corresponds to the underlying sensing elements. This merging approach achieves precise spatial zone detection while minimizing the increase in device complexity through compact integration.
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
Enables the detection of both moving and stationary individuals, providing accurate presence and motion sensing with enhanced signal processing capabilities, including direction of movement and temperature measurement, in a compact and cost-effective manner.
Implementation Method 1
The lens array is optically coupled to the one or more thermal sensing devices and includes multiple lenses, each of which is configured to direct incident thermal energy from at least a respective one of multiple different physical zones located within the monitored space onto the one or more thermal sensing devices
Implementation Method 2
Each thermal sensing device is configured to produce a direct current output that is sustained at a level substantially proportional to an amount of thermal energy being received at the thermal sensing device
Data Source
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AI summary
An apparatus configured to sense presence and motion in a monitored space includes one or more thermal sensing devices and a lens array. Each thermal sensing device is configured to produce a direct current output that is sustained at a level substantially proportional to an amount of thermal energy being received at the thermal sensing device. The lens array is coupled to the one or more thermal sensing devices and includes multiple lenses, each of which is configured to direct incident thermal energy from at least a respective one of multiple different physical zones located within the monitored space onto the one or more thermal sensing devices.