Quartz Temperature Probe Differential Frequency Measurement
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Solution Overview
Problem
Current quartz temperature measurement devices using crystal oscillators can achieve precision up to 1/10000° C but not beyond 1/1000000° C, limiting their ability to measure minute temperature changes with higher accuracy.
Innovation Solution
A quartz temperature measuring probe combining a first AT-cut crystal oscillator with a stable frequency and a second Y-cut or LC-cut oscillator, both from the same material and shape, to generate a differential frequency signal less than 10 kHz, allowing for precise temperature measurement using a differential frequency generating circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a single crystal oscillator with stable temperature characteristic (AT-cut) is used, then frequency stability is improved, but temperature measurement sensitivity deteriorates
Solution Approach 1:
The system divides the temperature measurement function into two separate crystal oscillators: one (AT-cut) dedicated to frequency stability and reference, and another (Y-cut or LC-cut) dedicated to temperature sensitivity. This segmentation allows each oscillator to be optimized for its specific function, resolving the contradiction between stability and sensitivity.
Solution Approach 2:
Different crystal oscillators are assigned different cut orientations tailored to specific local functions: AT-cut for stability and Y-cut/LC-cut for sensitivity. This local quality differentiation enables the system to simultaneously achieve both frequency stability and temperature measurement sensitivity without compromise.
2Measurement precision
If two crystal oscillators with different cut orientations are combined, then temperature measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines two crystal oscillators with different cut orientations (AT-cut and Y-cut/LC-cut) into a single integrated temperature measurement device. By merging these complementary components, the system achieves high measurement precision while managing complexity through functional integration rather than separate systems.
Solution Approach 2:
The combined oscillator system serves multiple functions: the AT-cut oscillator provides frequency reference and stability, while the Y-cut/LC-cut oscillator provides temperature sensitivity. Together they form a universal temperature measurement solution that achieves both stability and precision without requiring separate independent systems.
3Measurement precision
If differential frequency between two oscillators is made small (<10 kHz), then temperature measurement precision is improved, but signal strength deteriorates
Solution Approach 1:
The system carefully adjusts the frequency parameters of the two crystal oscillators to achieve a small differential frequency (<10 kHz) that optimizes temperature measurement precision. This parameter optimization balances the contradiction by selecting frequency values that minimize the differential while maintaining adequate signal strength for accurate measurement.
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 temperature measurement with precision ranging from 1/1000000° C to 9/1000000° C by utilizing a differential frequency signal, overcoming the limitations of existing devices and achieving high precision in temperature measurement.
Implementation Method 1
a first crystal oscillator of AT-cut orientation having a temperature characteristic in which its oscillating frequency is stable with temperature; a second crystal oscillator of Y-cut or LC-cut orientation having a temperature characteristic in which its oscillating frequency significantly changes with temperature
Data Source
AI summary
A crystal oscillator (31) (Y-cut) has a temperature characteristic in which its oscillating frequency significantly changes with temperature, whereas a crystal oscillator (32) (AT-cut) has a temperature characteristic in which its oscillating frequency is stable with temperature. Crystal oscillators (31, 32) are cut from a raw material of the same type and configured to be substantially equal in shape, material, and size, and provide a combination of oscillation frequencies such that the frequency of a signal generated by a differential frequency circuit (35) will be less than or equal to 10 kHz within a measuring temperature range of 21 to 30° C. The frequency of a signal generated by differential frequency generating circuit (35) is output to a measurement apparatus main unit and a frequency counting circuit (15) measures the frequency of this signal by a reciprocal counting method to obtain at least eight or more significant digits.