Piezoelectric Device Thermal Bridge for Frequency Stability
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Solution Overview
Problem
Surface mounting-type piezoelectric oscillators face challenges in achieving stable temperature-frequency characteristics and frequency drift characteristics due to temperature differences between the piezoelectric vibration device inside the oscillator and the temperature sensor mounted outside, leading to inaccurate frequency corrections and deteriorated startup performance.
Innovation Solution
A piezoelectric device configuration where a metal lid member, thermally connected to the piezoelectric vibration device through a high thermal conductivity heat transfer member, is used to ensure the temperature sensor detects a temperature equivalent to the vibration device, thereby improving frequency drift characteristics by eliminating incorrect temperature data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the temperature sensor is mounted outside the piezoelectric vibrator package, then the device complexity is reduced and ease of manufacture is improved, but temperature measurement precision deteriorates due to temperature difference between the sensor and the piezoelectric vibration device
Solution Approach 1:
A heat transfer member is introduced as an intermediary component between the piezoelectric vibration device and the temperature sensor. This heat transfer member has high thermal conductivity and is thermally connected to both the piezoelectric vibration device and the temperature sensor, allowing accurate temperature measurement while keeping the sensor outside the package. The heat transfer member acts as a thermal bridge that transmits temperature information from the vibration device to the external sensor.
2Measurement precision
If the temperature sensor is placed close to the piezoelectric vibration device, then temperature measurement precision is improved, but heat from the amplifier may be detected causing frequency drift
Solution Approach 1:
The heat transfer member is positioned and configured to selectively transfer heat from the piezoelectric vibration device while isolating the temperature sensor from heat generated by the amplifier. The local thermal coupling is optimized so that the sensor region receives thermal information primarily from the vibration device through the heat transfer member, while the amplifier's heat does not significantly affect the measurement point.
3Measurement precision
If a heat transfer member with high thermal conductivity is used, then temperature detection accuracy is improved, but device complexity increases
Solution Approach 1:
The heat transfer member serves multiple functions: it acts as a thermal bridge for accurate temperature measurement, provides mechanical support for mounting the temperature sensor, and can serve as part of the packaging structure. By integrating these functions into a single component, the overall device complexity is minimized while achieving accurate temperature detection.
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
This configuration ensures accurate temperature detection and correction, enhancing the stability and accuracy of temperature-frequency characteristics and frequency drift performance during startup.
Implementation Method 1
a heat transfer member having thermal conductivity higher than that of an insulating material of the insulating substrate and connecting the external pad and the lid member
Implementation Method 2
an insulating substrate that includes a piezoelectric vibration device
Data Source
AI summary
A piezoelectric device includes an insulating substrate, a piezoelectric vibration device that is mounted on a device mounting pad, a metal lid member that seals the piezoelectric vibration device in an airtight manner, an external pad that is arranged outside the insulating substrate, an oscillation circuit, a temperature compensation circuit, and a temperature sensor. The lid member and the temperature sensor or the lid member and the IC component are connected to each other so as to be heat-transferable, and a heat transfer member having thermal conductivity higher than that of the material of the insulating substrate is additionally included.