Varactor Inductor Resonant Circuit for Sealed Package Pressure Measurement
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Solution Overview
Problem
Existing pressure sensing technologies lack efficient and accurate methods to measure gas pressure within hermetically sealed packages, particularly upon opening, due to limitations in detecting pressure changes using conventional varactors and inductors.
Innovation Solution
A pressure sensing device comprising a varactor and an inductor forms a resonant circuit, where ionizing a gas within the varactor's aperture creates a plasma causing micro-discharge, influencing capacitance and determining resonant frequency, which is correlated with gas pressure, allowing for precise pressure measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional varactors and inductors are used for pressure sensing, then the device structure is simple, but the measurement precision and sensitivity are insufficient
Solution Approach 1:
The patent changes the operational parameters of the varactor by ionizing the gas within it to create a plasma state. This transforms the varactor from a conventional semiconductor device into a plasma-filled resonant element, fundamentally altering its electrical characteristics and enabling high-precision pressure measurement through resonant frequency detection
Solution Approach 2:
The patent replaces conventional mechanical or electronic pressure sensing mechanisms with a plasma-based resonant system. By substituting traditional sensing elements with a plasma-filled varactor that operates at resonant frequency, the system achieves superior measurement precision while maintaining practical device complexity
2Measurement precision
If a varactor with ionized gas plasma is used, then the sensitivity and accuracy of pressure detection is improved, but the energy consumption increases due to ionization requirements
Solution Approach 1:
The patent employs periodic pulsed voltage application to the varactor instead of continuous power supply. The ionization process is activated in periodic pulses, allowing the plasma to be created only when needed for measurement, thereby reducing overall energy consumption while maintaining measurement accuracy
Solution Approach 2:
The resonant circuit serves multiple functions: it acts as both the ionization excitation mechanism and the pressure sensing element. The same plasma-filled varactor that consumes energy for ionization also provides the pressure measurement function, eliminating the need for separate high-energy ionization sources and reducing total system energy requirements
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 solution enables accurate and efficient detection of gas pressure changes within sealed packages by measuring the resonant frequency of the varactor-inductor circuit, enhancing sensitivity and accuracy compared to conventional methods.
Implementation Method 1
The inductor and the varactor form a resonant circuit that resonates at a resonant frequency. The resonant frequency is a function of a pressure of the gas.
Implementation Method 2
ionizing a gas within an aperture of the varactor to form a plasma within the aperture
Implementation Method 3
using the plasma to cause a micro-discharge within the aperture
Implementation Method 4
causing a micro-discharge within the aperture, wherein a number of photons, and ionized particles including free electrons, in the micro-discharge impacting the aperture is related to a capacitance of a varactor
Data Source
AI summary
Described herein is an apparatus that includes a varactor and an inductor to form a resonant circuit that oscillates at a resonant frequency. The resonant frequency is a function of a pressure of a gas within an aperture of the varactor. In some embodiment, the varactor includes a first layer of p-type material, a first layer of n-type material, and a first np junction formed between the layer of p-type material and the layer of n-type material. The aperture extends at least partially through the layer of p-type material, at least partially through the layer of n-type material, and entirely through the np junction.