Micro-device Encapsulation with Opaque Light-absorbing Layer
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Solution Overview
Problem
In the packaging of optical micro devices, existing technologies fail to effectively prevent unwanted scattered light and moisture ingress, which can degrade the optical performance and mechanical stability of micro devices.
Innovation Solution
An encapsulated micro device design featuring a transparent encapsulation cover with an opaque layered structure that includes a moisture-absorbing material, such as zirconium compounds or amorphous carbon, to absorb light and moisture, combined with spacer walls that further define the chamber and enhance adhesion, allowing for precise positioning of the aperture layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a transparent encapsulation cover is used to allow optical signals to pass through, then optical performance is improved, but unwanted scattered light can exit the transparent window and cause optical noise
Solution Approach 1:
The encapsulation cover is segmented into different functional regions: a transparent region for optical signal transmission and an opaque region with light-absorbing material to trap scattered light. This segmentation allows simultaneous achievement of optical signal passage and scattered light elimination.
Solution Approach 2:
Different regions of the encapsulation cover have different optical properties - the first region is transparent to allow light passage while the second region contains light-absorbing material to absorb scattered light. This local differentiation resolves the contradiction between transparency and light trapping.
2Reliability
If the micro chamber is sealed to protect the micro device, then device protection is improved, but moisture content cannot be minimized
Solution Approach 1:
A moisture-absorbing layer is introduced into the sealed micro chamber to actively remove and absorb moisture. This extraction of harmful moisture from the sealed environment maintains both device protection and low moisture content.
Solution Approach 2:
The moisture-absorbing layer acts as an intermediary substance within the sealed chamber that mediates between the sealed environment and moisture control requirements, allowing the chamber to remain sealed while maintaining low humidity.
3Reliability
If separate layers are used for aperture and moisture absorption, then functional performance is improved, but device complexity and fabrication difficulty increase
Solution Approach 1:
The aperture layer and moisture-absorbing layer are merged into a single integrated layer that simultaneously provides both aperture function and moisture absorption capability. This reduces the number of layers from two to one while maintaining both functions.
Solution Approach 2:
The combined layer serves multiple functions: it acts as both an aperture structure and a moisture-absorbing layer. This multi-functionality eliminates the need for separate layers, reducing device complexity while maintaining functional performance.
4Reliability
If multiple separate layers are fabricated, then functional requirements are met, but manufacturing precision and alignment difficulty increase
Solution Approach 1:
By combining the aperture and moisture-absorbing functions into a single layer formed in one fabrication step, the need for precise alignment between multiple layers is eliminated, significantly reducing manufacturing precision requirements.
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 design improves mechanical and optical performance by reducing optical noise, increasing contrast between the 'on' and 'off' states of the micro device, and simplifies fabrication by combining the aperture and moisture-absorbing layers into a single layer, while maintaining high precision in manufacturing.
Implementation Method 1
The layered structure can include an opening over the micro device and is configured to absorb light and moisture in the chamber
Implementation Method 2
it is also desirable to minimize moisture content in the micro chambers because the performance of many micro devices can be affected by moisture
Data Source
AI summary
An encapsulated micro device includes a micro device on a substrate within a chamber, a transparent encapsulation cover in part defining the chamber, an opaque layered structure on the encapsulation cover and inside the chamber. The layered structure includes an opening over the micro device and is configured to absorb light and moisture in the chamber. A spacer wall between the substrate and the encapsulation cover in part defines the chamber.