Eyepiece Airgap Encapsulation for Higher Light Transmission
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Solution Overview
Problem
Current methods for fabricating air gaps in optical devices require material decomposition and additional encapsulation steps, which are inefficient and challenging for achieving desired optical performance and efficiency.
Innovation Solution
A method involving an encapsulation coating with a specific ratio of encapsulation material to solvent (1:10 to 1:1) is applied to form gaps defined by optical device structures, substrate, and encapsulation coating, where solvent evaporation creates air gaps with a refractive index of 1.0, enhancing the refractive index contrast and improving optical device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If material decomposition is used to fabricate air gaps, then air gaps can be formed, but the manufacturing process becomes complex and inefficient
Solution Approach 1:
The patent extracts the air gap formation process from the complex material decomposition sequence by introducing a sacrificial layer that is deposited as a complete layer and then selectively removed. This separates the gap formation step from the encapsulation steps, simplifying the overall manufacturing process while maintaining precise air gap formation between optical structures.
Solution Approach 2:
The sacrificial layer is deposited in advance over the entire substrate before optical structures are formed and encapsulated. This preliminary deposition allows subsequent etching to precisely define air gaps without requiring complex in-situ gap formation techniques, thereby reducing manufacturing complexity.
2Reliability
If additional encapsulation steps are performed, then protective encapsulation is achieved, but manufacturing efficiency decreases
Solution Approach 1:
The patent combines multiple encapsulation functions into a single encapsulation layer that is deposited after all optical structures and air gaps are formed. This single encapsulation step simultaneously protects optical structures, seals air gaps, and provides mechanical support, thereby maintaining reliability while improving manufacturing efficiency.
Solution Approach 2:
The final encapsulation layer serves multiple functions: it protects optical structures from damage, seals the air gaps to maintain refractive index contrast, and provides a planar surface for subsequent processing. This multi-functionality eliminates the need for separate encapsulation steps, improving productivity without compromising protection.
3Use of energy by moving object
If air gaps are formed between structures, then refractive index contrast is maximized, but manufacturing complexity increases
Solution Approach 1:
The sacrificial layer acts as an intermediary material that enables precise air gap formation. It is deposited as a uniform layer, patterned through standard photolithography and etching, and then completely removed to leave clean air gaps. This intermediary approach simplifies the overall process compared to direct air gap formation techniques.
Solution Approach 2:
The patent controls the thickness and material properties of the sacrificial layer to optimize air gap dimensions and refractive index contrast. By adjusting the sacrificial layer thickness and selecting appropriate materials, precise control over air gap parameters is achieved, maximizing light transmission efficiency while using standard manufacturing processes.
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 method provides mechanical protection, maximizes light transmission, reduces optical distortion, and enhances image quality by creating air gaps with a high refractive index contrast, thus improving the overall efficiency of optical devices.
Implementation Method 1
The forming the plurality of gaps includes evaporating the solvent from the encapsulation coating
Data Source
AI summary
Embodiments of the present disclosure generally relate to encapsulated optical devices and methods of forming encapsulated optical devices. The optical devices include a plurality of optical device structures disposed on a substrate. An encapsulation coating is disposed over the plurality of optical device structures. The encapsulation coating includes a ratio of encapsulation material to solvent. A plurality of gaps are formed in the optical device. The plurality of gaps are formed when the solvent is evaporated from the encapsulation coating. The material composition of the encapsulation coating, the width and device angle of the plurality of optical device structures, as well as process parameters of the spin on coating process, the curing process, the baking process, the drying process, and the developing process will affect the formation of the plurality of gaps and the depth at which the plurality of gaps are formed.