Resonator Package Lid Emissivity Layout for Temperature Stability
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Solution Overview
Problem
The thermal insulation properties of ceramic packages in temperature-compensated oscillators lead to unstable temperature conditions for crystal resonators, deteriorating oscillation characteristics due to heat confinement.
Innovation Solution
A resonator device design featuring a silicon substrate base with an integrated circuit and a silicon substrate lid, where the lid has a radiation layer with higher emissivity than the lid itself, arranged on its inner surfaces to efficiently absorb and radiate heat, stabilizing the resonator element's temperature and improving oscillation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ceramic package with high thermal insulation properties is used to house the crystal resonator and IC, then the package provides good protection and integration, but the heat generated by the IC is confined, causing unstable temperature of the crystal resonator and deteriorated oscillation characteristic
Solution Approach 1:
The lid is designed with different emissivity properties for different regions: the first region (facing the crystal resonator) has low emissivity to reflect heat back, while the second region (outer surface) has high emissivity to radiate heat outward. This local differentiation of thermal properties allows simultaneous heat retention for the resonator and heat dissipation from the package.
Solution Approach 2:
The lid employs a composite structure combining materials or surface treatments with different emissivity characteristics in different regions. This composite approach enables the lid to perform dual functions: protecting and thermally isolating the crystal resonator from IC heat while also providing overall heat dissipation from the package.
2Device complexity
If the IC is integrated with the crystal resonator in a single ceramic package, then device complexity is reduced and integration is improved, but temperature control of the resonator becomes difficult due to heat confinement
Solution Approach 1:
The lid's differential emissivity design creates localized thermal zones: a low-emissivity region protecting the resonator from IC heat and a high-emissivity region for external heat dissipation. This allows integrated packaging while maintaining resonator temperature stability through localized thermal management.
Solution Approach 2:
The lid acts as an intermediary thermal management component between the IC and the crystal resonator. By strategically positioning regions of different emissivity, the lid mediates heat transfer, blocking harmful heat from reaching the resonator while facilitating overall package heat dissipation.
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 resonator device achieves enhanced temperature stability and reduced frequency deviation, resulting in higher accuracy and reliability of oscillation characteristics.
Implementation Method 1
a radiation layer which is arranged at the inner surface of the lid, and is higher in emissivity than the lid
Data Source
AI summary
A resonator device includes a resonator element, a base which has a first surface and a second surface that are in front-back relation, and in which the resonator element is arranged at the first surface, an integrated circuit provided to the base, a lid which has an inner surface opposed to the resonator element, and an outer surface in a front-back relationship with the inner surface, and which is bonded to the base so as to house the resonator element, and a radiation layer which is arranged at the inner surface of the lid, and is higher in emissivity than the lid.