Small-Cavity Optical Packaging Structure for Heat-Resistant Sealing
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Solution Overview
Problem
Large cavity packaging structures for electronic devices are prone to damage due to air expansion caused by heating, leading to air leakage and water ingress, which affects light signal transmission quality and the reliability of the components.
Innovation Solution
A small cavity packaging structure is designed with a hermetically connected outer cover and a transparent inner cover, where the outer cover is inserted into annular grooves on the optical device, and an insulating packaging layer is used to secure the components, reducing the volume of air inside and preventing seal damage from heat expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large cavity packaging structure is used, then the optical device can be properly mounted and connected, but the air inside the cavity expands when heated, causing the adhesive to fail and the seal to break
Solution Approach 1:
The cavity is segmented into a small internal cavity and an external region by introducing a transparent inner cover. This segmentation isolates the air volume that can expand, limiting its harmful effects while maintaining the necessary optical functionality.
Solution Approach 2:
The transparent inner cover is nested within the outer cover, creating a nested structure where the inner cover defines a small protected cavity. This nested arrangement allows the optical device to be mounted on the substrate while confining the air expansion to a small, controlled space.
2Illumination intensity
If a transparent glass plate is fixed to the outer cover opening, then light can pass through, but the adhesive connection is vulnerable to breaking from air expansion
Solution Approach 1:
The transparent inner cover is nested within the outer cover opening, creating a protective barrier that shields the adhesive connection from the expansive forces of heated air, while still allowing light to pass through the transparent material.
Solution Approach 2:
The transparent inner cover is positioned specifically at the opening region where light transmission is needed, providing localized protection to the adhesive connection in this critical area without affecting other parts of the packaging structure.
3Adaptability or versatility
If the cavity is large to accommodate components, then all components can be mounted, but the packaging structure becomes vulnerable to heat-induced damage
Solution Approach 1:
The packaging structure is segmented into a small protected cavity for sensitive components and an external region for other components. The transparent inner cover creates this segmentation, allowing the packaging to accommodate various components while protecting the critical internal region from heat-induced damage.
Solution Approach 2:
Different regions of the packaging structure have different qualities: the internal cavity behind the transparent inner cover provides enhanced protection and stability, while the external region offers component accommodation flexibility. This local differentiation resolves the contradiction between versatility and stability.
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 minimizes air expansion-induced damage, enhancing the reliability and stability of the packaging structure by maintaining a secure seal and reducing the risk of air leakage, while also allowing for efficient light signal transmission.
Implementation Method 1
a transparent inner cover disposed inside the opening and sealing the opening, the upper surface of the optical device, the outer cover and the transparent inner cover are sealed to form a cavity, a light signal path between the optical region and the exterior of the packaging structure passes through the opening and the transparent inner cover
Implementation Method 2
an outer cover hermetically connected to the upper surface of the optical device and surrounding the optical region
Implementation Method 3
the small cavity packaging structure adopted in the present disclosure has the following advantages: (1) The cavity is relatively small, and there is less air inside, so even if the air inside the cavity expands due to heating, it is less likely to damage the packaging structure
Data Source
AI summary
The present disclosure pertains to a packaging structure for electronic devices, which comprises: a substrate and an optical device fixed to the substrate, an upper surface of the optical device has an optical region for receiving and/or transmitting light signals; an outer cover hermetically connected to the upper surface of the optical device and surrounding the optical region, which has an opening; and a transparent inner cover disposed inside the opening and sealing the opening, the upper surface of the optical device, the outer cover and the transparent inner cover are sealed to form a cavity, and a light signal path between the optical region and the exterior of the packaging structure passes through the opening and the transparent inner cover. The present disclosure provides a small cavity packaging structure, which maintains the sealing integrity of the cavity even when the air inside the cavity expands due to heating.