Protected Metasurface Lens Layout for Scratch-Resistant Optics
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Solution Overview
Problem
Wafer-level stacking often results in lenses of optical devices being scratched or damaged during subsequent handling due to their exposure on the device surface.
Innovation Solution
The lens structure is positioned on the side of the substrate facing the optical aperture, protected within the interior of the device, with a low-index material or vacuum between the active region and aperture, and a thin glass support to minimize optical aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the lens structure is positioned on the outer surface of the device for easy access and integration, then the device structure is simplified and manufacturing is easier, but the lens becomes vulnerable to scratches and damage during handling
Solution Approach 1:
Instead of placing the lens on the outer surface for easy access, the patent inverts the arrangement by positioning the lens on the inner surface of the lens substrate, facing the aperture substrate. This inversion protects the lens from external damage while maintaining optical functionality through the substrate.
Solution Approach 2:
The lens structure is nested within the lens substrate, with the aperture substrate positioned in front of it. This nesting arrangement allows the lens to be protected inside the substrate while still performing its optical function, effectively hiding the vulnerable component within the device structure.
2Reliability
If a thick glass support is used to protect the lens structure, then the lens is better protected from damage, but optical aberrations increase and device size grows
Solution Approach 1:
The patent changes the thickness parameter of the glass support to be relatively thin (e.g., 200 micrometers or less). This parameter optimization provides sufficient mechanical protection while minimizing optical path length through the glass, thereby reducing aberrations caused by the flat glass surface.
Solution Approach 2:
The patent applies different properties to different parts of the support structure. The lens substrate provides protection where needed, while the opening in the spacer creates an air or low-index material region that minimizes optical interference. This local differentiation allows protection without excessive aberrations.
3Productivity
If the lens structure is exposed on the device surface for straightforward assembly, then manufacturing is simpler, but the lens is more susceptible to damage during handling
Solution Approach 1:
The lens structure is pre-positioned on the inner surface of the lens substrate before final device assembly. This preliminary positioning ensures the lens is already protected when the aperture substrate and spacer are attached, eliminating the need for separate protective steps while maintaining manufacturing efficiency.
Solution Approach 2:
The lens substrate acts as an intermediary between the lens structure and the external environment. It provides a protective barrier that shields the lens from handling damage while allowing light to pass through to the aperture, effectively mediating between protection requirements and optical functionality.
4Strength
If a thick glass support is used to support the lens structure, then mechanical strength and protection are improved, but optical aberrations from the flat glass surface increase
Solution Approach 1:
The patent optimizes the thickness parameter of the glass support to a specific range (relatively thin, e.g., 200 micrometers or less). This parameter change provides adequate mechanical strength for protection while minimizing the optical path length through the glass, thereby reducing aberrations caused by the flat glass surface.
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
Reduces the likelihood of lens damage and maintains compact device size while minimizing optical aberrations, enhancing manufacturing efficiency and reducing costs.
Implementation Method 1
The opening has an index of refraction equal to or less than 1.0
Implementation Method 2
The lens structure is defined throughout a metasurface distributed across a surface of the support and comprises meta-atoms configured to change a local amplitude, a local phase, or both, of a light wave at an application wavelength
Data Source
AI summary
The present disclosure describes, among other things, optical devices in which a lens structure is closer to an aperture substrate than is a support on which the lens structure is disposed. The lens structure is defined throughout a metasurface that is distributed across a surface of a support of a lens substrate and that comprises metaatoms configured to change a local amplitude, a local phase, or both, of a light wave at an application wavelength. The present disclosure also describes assemblies incorporating one or more such optical devices, as well as methods of manufacturing the optical devices.