OCXO Resonator Windbreak Structure for Phase Noise Stability

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Solution Overview

Problem

Oven-controlled crystal oscillators (OCXO) face issues with noise characteristics due to exposure to wind and temperature fluctuations when the third container is omitted for size reduction, leading to instability in output signal quality.

Innovation Solution

The design incorporates a leg part surrounding the second resonator element on the substrate, creating a windbreak effect and maintaining a stable temperature, while the packages are made with materials like alumina and Kovar to reduce thermal stress and enhance mechanical strength, with inner and outer packages being thermally insulated to improve vibration characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the third container is omitted to reduce device size, then the device size is reduced, but the second resonator element becomes exposed to wind and temperature fluctuations, worsening noise characteristics

Engineering Contradiction:

Improvedevice sizeVSAvoidtemperature fluctuation and wind exposure

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a windbreak structure as an intermediary element between the external environment and the second resonator element. This windbreak serves as a mediator that blocks wind and reduces temperature fluctuations without requiring a complete third container, thus protecting the resonator while maintaining a compact device size.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The windbreak structure functions as a protective shell or barrier that selectively filters environmental factors. Rather than enclosing the resonator completely (which would increase size), this flexible protective structure provides targeted shielding against wind and temperature variations, allowing the resonator to remain partially exposed while still protected from harmful factors.

Inventive Principle:

Principle #30Flexible shells and thin films

2Device complexity

If the second resonator element is exposed to reduce complexity, then device complexity is reduced, but the noise characteristic of the output signal deteriorates due to environmental exposure

Engineering Contradiction:

Improvecontainer structureVSAvoidnoise characteristic

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The windbreak acts as an intermediary protective element that adds minimal structural complexity while significantly improving reliability. Instead of implementing a full third container (high complexity), the windbreak provides essential protection against environmental factors, thereby maintaining noise characteristics without substantial increase in device complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Stability of the object's composition

If thermal insulation is enhanced to stabilize temperature, then temperature stability is improved, but thermal stress on the resonator elements increases

Engineering Contradiction:

Improvetemperature stabilityVSAvoidthermal stress

Core Design Contradiction:

Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The patent applies thermal insulation selectively rather than uniformly throughout the entire device. The windbreak and insulation structures are positioned specifically to protect the second resonator element from temperature fluctuations, while the first resonator element in its dedicated container maintains its own thermal environment. This localized approach provides temperature stability where needed without subjecting all components to excessive thermal stress.

Inventive Principle:

Principle #3Local quality

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 effectively suppresses temperature fluctuations caused by wind, stabilizes the resonator elements, and enhances the phase noise characteristics of the output signal, achieving improved stability and efficiency in the oscillator's performance.

Implementation Method 1

The design incorporates a leg part surrounding the second resonator element on the substrate, creating a windbreak effect and maintaining a stable temperature

Methodology Applied

Scientific EffectWindbreak effect:

Implementation Method 2

the packages are made with materials like alumina and Kovar to reduce thermal stress and enhance mechanical strength, with inner and outer packages being thermally insulated

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS11817825B2Oscillator

Publication Date: 2023.11.14 SEIKO EPSON CORP

AI summary

An oscillator includes a first resonator element, a circuit element configured to oscillate the first resonator element to generate an oscillation signal, a first package which includes a substrate, and has a housing space configured to house the first resonator element and the circuit element at one principal surface side of the substrate, a second resonator element which is disposed at another principal surface side of the substrate, and an oscillation frequency of which is controlled based on the oscillation signal, and a leg part which is disposed at the another principal surface side of the substrate, and which is arranged so as to surround the second resonator element in a plan view of the substrate.