Suspended Optical Air Slit Manufacturing via Sacrificial Templates

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Solution Overview

Problem

Existing methods for creating optical air slits, such as those used in hyperspectral imaging systems, face challenges in achieving precise and durable narrow slits with consistent dimensions across the electromagnetic spectrum.

Innovation Solution

A method involving a substrate with a metal layer having a slit narrower than the opening, formed through a process including sacrificial material deposition, polishing, metalization, photolithographic slit creation, and electroplating, with the slit being suspended over the opening while supported by the substrate, allowing for precise control over slit dimensions and material selection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional methods (laser cutting, photolithography, EDM) are used to create optical air slits, then the manufacturing process is relatively simple, but the manufacturing precision and consistency of slit dimensions are insufficient

Engineering Contradiction:

Improveslit dimension precisionVSAvoidmanufacturing process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The manufacturing process is divided into multiple sequential steps: forming sacrificial material in the opening, depositing metal layer, photolithographically forming the slit pattern, etching the metal layer, and removing sacrificial material. This segmentation allows each step to be optimized independently for precision while maintaining overall process manageability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Sacrificial material is deposited into the opening before metal layer formation, creating a preliminary structure that defines the future slit position and dimensions. This preliminary action ensures precise slit formation by pre-establishing the geometric constraints before the actual metal structuring occurs

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If narrower slits are created to improve spectral resolution, then the imaging precision improves, but the durability and structural stability of the slit decreases

Engineering Contradiction:

Improvespectral resolutionVSAvoidslit structural stability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

A thin metal layer is deposited over the sacrificial material to form the slit structure. This thin film approach allows creation of narrow slits for high spectral resolution while the continuous metal layer maintains structural integrity and durability

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The structure combines sacrificial material ( providing mechanical support and definition) with metal layer (providing optical durability and precision). This composite approach enables narrow, stable slits by combining the geometric precision of the sacrificial material with the structural strength of metal

Inventive Principle:

Principle #40Composite materials

3Reliability

If the metal layer is made thicker to improve durability, then the reliability improves, but the manufacturing precision and slit dimension control deteriorates

Engineering Contradiction:

Improvemetal layer durabilityVSAvoidslit dimension control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The sacrificial material is deposited first to establish precise dimensional constraints. The metal layer is then deposited conformally over this preliminary structure, ensuring that even thicker metal layers maintain precise slit dimensions defined by the underlying sacrificial material geometry

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The metal layer thickness is controlled locally by the geometry of the sacrificial material. The sacrificial material provides a template that ensures uniform and precise metal layer thickness across the slit region, maintaining manufacturing precision regardless of overall metal layer thickness

Inventive Principle:

Principle #3Local quality

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 approach enables the creation of optical slits with precise dimensions and enhanced durability, suitable for hyperspectral imaging systems, by ensuring consistent slit formation and material properties across the electromagnetic spectrum.

Implementation Method 1

PVD

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Implementation Method 2

CVD

Methodology Applied

Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Implementation Method 3

photolihographically forming a slit in the photolithographically processable material

Methodology Applied

Scientific EffectPhotodecomposition: Photodissociation

Implementation Method 4

the unexposed portions of the metallized layer are electroplated to a predetermined thickness

Methodology Applied

Scientific EffectElectroplating: Electroplating

Data Source

PatentUS9235115B2Optical air slit and method for manufacturing optical air slits

Publication Date: 2016.01.12 RAYTHEON CO

AI summary

A structure having an optical slit therein. The structure includes a substrate having an opening therethrough and a metal layer disposed on the substrate, such metal layer having a photolithographically formed slit therein, such slit being narrower than the opening and being disposed over the opening, portions of the metal layer disposed adjacent the slit being suspended over the opening and other portions of the metal layer being supported by the substrate.