Cryogenic Piezoelectric Resonator Sensing With Heated Oscillator Circuit
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Solution Overview
Problem
Existing sensing devices using piezoelectric resonators face instability in oscillation due to temperature fluctuations affecting the integrated circuit chip, leading to operational failures and reduced oscillation margin, especially when cooled to cryogenic temperatures.
Innovation Solution
A sensing device with a piezoelectric resonator, a temperature changing unit, a frequency measuring unit, a heater, and a power supplying unit, where the heater is separate from the temperature changing unit, and the power supplying unit adjusts voltage to stabilize the oscillator circuit's operation across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the integrated circuit chip is cooled to cryogenic temperatures to enable the piezoelectric resonator to sense substances, then the sensing sensitivity is improved, but the oscillator circuit may stop functioning due to excessive cooling
Solution Approach 1:
The device is divided into two separate thermal zones: the piezoelectric resonator is cooled to cryogenic temperatures for high-sensitivity sensing, while the integrated circuit chip containing the oscillator circuit is maintained at a higher temperature by a dedicated heater to ensure continuous operation. This spatial and functional segmentation resolves the contradiction between sensing sensitivity and circuit reliability.
Solution Approach 2:
A temperature control mechanism with separate heating for the integrated circuit chip acts as an intermediary system that decouples the thermal requirements of the resonator and the circuit. The heater specifically compensates for temperature drops in the circuit portion, serving as a mediator that protects the oscillator circuit from the cryogenic cooling applied to the resonator.
2Reliability
If the integrated circuit chip is maintained at higher temperatures to ensure oscillator circuit operation, then the circuit reliability is improved, but the piezoelectric resonator sensitivity decreases
Solution Approach 1:
The device structure separates the thermal management of the resonator and the integrated circuit chip. The resonator is cooled to cryogenic temperatures for optimal sensing performance, while the circuit chip is thermally isolated and maintained at higher temperatures through dedicated heating, allowing each component to operate in its optimal temperature range simultaneously.
Solution Approach 2:
Different regions of the device are assigned different thermal properties: the piezoelectric resonator region is cooled to enhance sensing sensitivity, while the integrated circuit chip region is heated to maintain circuit reliability. This local differentiation of thermal conditions allows both contradictory requirements to be satisfied in their respective locations.
3Adaptability or versatility
If the ambient temperature of the oscillator circuit changes during sensing operations, then the device can operate in various environments, but the oscillation stability decreases
Solution Approach 1:
A temperature control system with feedback mechanism monitors the temperature of the integrated circuit chip and adjusts the heating power accordingly to maintain a stable operating temperature for the oscillator circuit, thereby stabilizing the oscillation frequency despite changes in ambient temperature or device orientation.
Solution Approach 2:
The temperature control mechanism acts as an intermediary that buffers the oscillator circuit from ambient temperature variations. By actively regulating the circuit chip temperature through heating when needed, the system isolates the sensitive oscillation circuit from external thermal disturbances, maintaining stable operation across different environmental conditions.
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 device enables stable oscillation and accurate frequency measurement of the piezoelectric resonator, even under temperature changes, by automatically configuring the voltage to maintain optimal operating conditions, reducing operational failures and expanding the device's application range.
Implementation Method 1
sensing device that senses a substance to be sensed by frequency change of a piezoelectric resonator
Implementation Method 2
A semiconductor of silicon or the like that configures the integrated circuit chip has a reduced density of a carrier when it is excessively cooled
Implementation Method 3
the crystal unit is cooled down to, for example, a cryogenic temperature of approximately -190°C to cause the gas to attach to the crystal unit
Data Source
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AI summary
A sensing device for sensing a substance to be sensed contained in a gas around a piezoelectric resonator based on change in an oscillation frequency of the piezoelectric resonator. The sensing device includes the piezoelectric resonator to which the substance to be sensed attaches by being cooled, a temperature changing unit, a substrate, a frequency measuring unit, a heater, and a power supplying unit. The temperature changing unit is configured to change a temperature of the piezoelectric resonator. An integrated circuit chip including an oscillator circuit that oscillates the piezoelectric resonator is disposed on the substrate. The frequency measuring unit receives a frequency signal output from the oscillator circuit and measures an oscillation frequency of the piezoelectric resonator. The heater is disposed separately from the temperature changing unit for heating the integrated circuit chip. The power supplying unit is configured to change an electric power supplied to the heater.