Passive Sensor Age and Temperature History via Material Diffusion
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Solution Overview
Problem
Existing technologies lack effective methods for determining the absolute age and temperature history of devices or systems without using power, particularly in scenarios where digital clocks are not applicable, such as during passive aging processes.
Innovation Solution
A passive sensor system utilizing dissimilar material pairs with diffusive interfaces, where one material diffuses into another over time, affecting electrical or optical properties, allowing for the determination of age and temperature history through measurable changes in conductance, capacitance, inductance, transmission, reflectance, or crystalline structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If digital clocks or powered sensors are used to track age and temperature history, then measurement precision is improved, but use of energy increases and reliability decreases during passive aging
Solution Approach 1:
The sensor system uses self-service by allowing the passive sensor itself to undergo diffusion processes that naturally record age and temperature history without requiring external power. The dissimilar material members automatically diffuse into each other based on temperature exposure, creating a self-powered recording mechanism that eliminates the need for powered clocks or active sensors during the aging period.
Solution Approach 2:
The patent applies preliminary action by pre-configuring dissimilar material members with specific diffusion characteristics before the aging process begins. These materials are selected and arranged to undergo predictable diffusion rates at different temperatures, effectively pre-programming the sensor to automatically record temperature history through the diffusion process itself, eliminating the need for powered recording devices during operation.
2Device complexity
If a single sensor element is used, then device complexity is reduced, but measurement precision decreases due to inability to independently determine age and temperature
Solution Approach 1:
The patent applies segmentation by dividing the sensing function into multiple sensor elements, each with different diffusion characteristics. This segmentation allows the system to independently determine both age and temperature history by comparing the diffusion states of different material pairs, as each element responds differently to the same thermal history, providing sufficient data to solve for both variables independently.
Solution Approach 2:
The patent uses composite materials by combining dissimilar material members with different diffusion coefficients into sensor elements. This composite approach creates sensor elements that are sensitive to temperature in predictable ways, and by using multiple such composite elements with varying material compositions, the system achieves the capability to independently determine both age and temperature history through comparative analysis.
3Measurement precision
If materials with high diffusion rates are used, then sensitivity to temperature changes is improved, but manufacturing precision requirements increase to control diffusion depth
Solution Approach 1:
The patent applies parameter changes by selecting material pairs with specific diffusion coefficients and activation energies that provide optimal temperature sensitivity while maintaining manufacturability. By carefully choosing materials whose diffusion rates change predictably with temperature, the system achieves high temperature sensitivity without requiring extreme manufacturing precision, as the diffusion process itself provides the measurement signal.
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 precise determination of age and temperature history independently of temperature, using multiple sensor elements with differing diffusion rates to provide accurate and reliable data without the need for power, suitable for various applications including warranty verification and environmental monitoring.
Implementation Method 1
the second material of the second member diffuses over time into the first material of the first member. The rate of diffusion for the second material to diffuse into the first material depends on a temperature of the passive sensor.
Data Source
AI summary
A passive sensor for historic age and temperature sensing, including a first member formed of a first material, the first material being either a metal or a semiconductor material and a second member formed of a second material, the second material being either a metal or a semiconductor material. A surface of the second member is in contact with a surface of the first member such that, over time, the second material of the second member diffuses into the first material of the first member. The rate of diffusion for the second material to diffuse into the first material depends on a temperature of the passive sensor. One of the electrical conductance, the electrical capacitance, the electrical inductance, the optical transmission, the optical reflectance, or the crystalline structure of the passive sensor depends on the amount of the second material that has diffused into the first member.