Piezoelectric Package with Integrated Thermistor for Frequency Stability
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Solution Overview
Problem
Existing piezoelectric device packages face challenges in maintaining stable frequency across a wide temperature range and require miniaturization while integrating circuitry, as they are prone to resonance frequency variations due to the placement of thermistors and resistance elements.
Innovation Solution
A piezoelectric device package design featuring a board with a thermistor layer and resistance layer on its lower surface, connected to specific terminals, and a cap lead covering the upper portion, which allows for accurate temperature measurement and integration of circuitry, reducing resonance frequency variations and enabling miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermistors and resistance elements are placed on the board to compensate for temperature variations, then frequency stability is improved, but device complexity and size increase
Solution Approach 1:
The patent combines the thermistor and resistance element directly onto the board substrate, merging multiple functional components into a single integrated structure. This eliminates the need for separate compensation circuits while maintaining frequency stability across temperature variations.
Solution Approach 2:
The board serves multiple functions: it acts as the structural substrate, the mounting platform for the piezoelectric device, and the integration carrier for both the thermistor and resistance elements. This multi-functionality reduces overall device complexity while achieving temperature compensation.
2Productivity
If the piezoelectric device package is miniaturized, then productivity and integration are improved, but maintaining frequency stability becomes more difficult
Solution Approach 1:
The thermistor and resistance elements are positioned on the reverse side of the board, nesting the compensation circuitry within the existing package structure. This allows miniaturization without compromising frequency stability, as the compensation elements are integrated into the same footprint.
3Length of moving object
If the piezoelectric device is thinned, then device size is reduced, but resonance frequency variation increases
Solution Approach 1:
The thermistor and resistance elements are pre-positioned on the board before the piezoelectric device is mounted. This preliminary arrangement ensures that temperature compensation is already in place when the device is thinned, preventing resonance frequency variations even in the reduced-thickness configuration.
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 effectively decreases resonance frequency variations and enables the integration of circuitry, providing a stable frequency source even with temperature changes, thus addressing the need for high-end piezoelectric device packages that can replace traditional temperature compensation crystal oscillators.
Implementation Method 1
When a voltage is applied to a piezoelectric device, stress is added thereto due to an electrostrictive effect, such that vibrations are generated
Implementation Method 2
When vibrations are generated, a regularly oscillating signal is generated by a piezoelectric effect
Implementation Method 3
a thermistor layer and a resistance layer disposed on the lower surface of the board
Data Source
AI summary
A piezoelectric device package includes a board having a lower surface and an upper surface, a plurality of terminals disposed on the lower surface, a piezoelectric device disposed on the upper surface, a thermistor layer and a resistance layer disposed on the lower surface, and a cap lead covering an upper portion of the board.