Crystal Oscillator Thinned Substrate Structure for High Frequency
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Solution Overview
Problem
Conventional crystal oscillators face challenges in achieving high oscillation frequencies while maintaining a lightweight design, as thick portions added for strength increase the device's weight, which is not conducive for thin and lightweight oscillators.
Innovation Solution
A method involving a piezoelectric substrate with a thinned region and a hollow frame, where the thinned region has a reduced thickness or is formed as a through hole, and electrodes are strategically placed to enhance strength and reduce weight, allowing for higher oscillation frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thick portion is added to the oscillation plate to prevent breakage and enhance strength, then the strength and reliability of the device is improved, but the total weight of the oscillation device increases
Solution Approach 1:
The oscillation plate is segmented into different thickness regions: a thinned central region for high-frequency oscillation and peripheral thick portions for strength. This segmentation allows different regions to serve different functions - the thin center reduces weight and increases frequency while the thick edges provide structural support and prevent breakage during manufacturing.
Solution Approach 2:
Different regions of the oscillation plate have different thickness qualities tailored to their specific needs. The central region is thinned to 50-150 micrometers for high-frequency performance, while peripheral regions maintain greater thickness for mechanical strength. This local differentiation resolves the contradiction between weight reduction and strength enhancement.
2Speed
If the thickness of the oscillation plate is reduced to achieve higher oscillation frequency, then the oscillation frequency is improved, but the strength of the substrate deteriorates making it prone to breakage
Solution Approach 1:
The substrate is divided into a thinned central oscillation region and thicker peripheral support regions. The central region thickness is controlled at 50-150 micrometers to achieve the desired high oscillation frequency, while the peripheral regions maintain greater thickness to provide mechanical strength and prevent breakage during handling and manufacturing.
Solution Approach 2:
The solution moves from a uniform two-dimensional thickness problem to a three-dimensional thickness distribution problem. By varying thickness in the vertical dimension across different spatial locations, the patent simultaneously achieves high frequency (through thinning) and high strength (through strategic thickening at edges and corners).
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 method effectively decreases the total weight of the crystal oscillator while maintaining the required oscillation frequency, ensuring the device's strength and performance in high-frequency communication applications.
Implementation Method 1
forming a first electrode portion on a surface of a piezoelectric substrate
Data Source
AI summary
A crystal oscillator includes an oscillating substrate, a hollow frame, a first electrode, and a second electrode. The oscillating substrate includes a main oscillating region and a thinned region that has a thickness smaller than that of the main oscillating region. The first and second electrodes are disposed on a first surface of the oscillating substrate and a second surface opposite to the first surface, respectively. The hollow frame is disposed on the second surface. The second electrode includes a second electrode portion that has at least one opening in positional correspondence with the thinned region. A method for making the crystal oscillator is also provided herein.