Optical Package Structure Moisture Ingress Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional image sensor package structures face issues with reliability and size due to moisture ingress, affecting image quality and electrical performance, and the encapsulation process often contaminates the transparent plate, leading to abnormal operation.
Innovation Solution
An optical package structure with a substrate, frame layer, optical unit, bonding layer, and transparent plate, where the encapsulation layer covers the lateral edges of the transparent plate and bonding layer, reducing moisture ingress and material usage, while the through holes are designed to prevent vapor diffusion and the lamination film absorbs mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the encapsulation layer covers the upper surface of the transparent plate, then the encapsulation process is simplified, but the transparent plate surface is contaminated causing abnormal operation
Solution Approach 1:
The encapsulation layer is segmented into two distinct regions: a first encapsulation region covering the substrate, frame layer, and lateral edge of the transparent plate, and a second encapsulation region covering the lower surface of the transparent plate. This segmentation prevents the encapsulation layer from contacting the upper surface of the transparent plate, eliminating contamination while maintaining protective encapsulation.
2Volume of stationary object
If the package size is reduced, then material consumption and production cost are reduced, but moisture ingress through through holes increases affecting reliability
Solution Approach 1:
The encapsulation layer exhibits local quality differentiation with different regions having different protective functions. The first encapsulation region provides moisture barrier protection for the substrate and frame layer, while the second encapsulation region protects the lower surface of the transparent plate. This localized protection strategy maintains reliability in a compact package design.
3Strength
If the encapsulation layer covers the frame layer, then structural protection is improved, but the transparent plate upper surface is contaminated during encapsulation
Solution Approach 1:
The encapsulation protection is extended to a third dimension by covering the lower surface of the transparent plate (second encapsulation region) in addition to protecting the substrate and frame layer (first encapsulation region). This dimensional expansion provides comprehensive structural protection without requiring the encapsulation layer to contact the upper surface of the transparent plate, thus avoiding contamination.
Data Source
AI summary
An optical package structure is provided. The optical package structure includes a substrate, a frame layer, an optical unit, a bonding layer, a transparent plate and an encapsulation layer. The frame layer formed on the substrate surrounds a cavity where the optical unit is located. The bonding layer covers a portion of an upper edge of the frame layer and exposes the other portion of the upper edge of the frame layer. The transparent plate mounted on the bonding layer extends across the optical unit and extends beyond an outer edge of the bonding layer. The encapsulation layer covers a lateral edge of the transparent plate and the outer edge of the bonding layer.