Dielectric Mirror Transmissive Window for Gas Analyzer Sealing
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Solution Overview
Problem
Existing optical mirror elements for gas analyzers, such as those in Herriott Cells, face challenges in maintaining a controlled environment and reducing noise due to the use of glass plugs for sealing, which are costly and time-consuming to implement, especially for in-field applications.
Innovation Solution
The development of optical mirror elements with a transmissive window, where a portion of the reflective coating is masked or etched to create an anti-reflective window, allowing light to pass through while maintaining reflectivity elsewhere, and housed in a structure that facilitates controlled environments without the need for glass plugs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass plugs are used to seal the cavity, then the controlled environment is maintained, but the manufacturing cost and time increase
Solution Approach 1:
The patent removes the glass plug component entirely and replaces it with an integrated transmissive window formed directly in the mirror element during coating deposition. This extraction of the separate sealing component eliminates the associated manufacturing steps while maintaining cavity sealing through the deposited coating layers.
Solution Approach 2:
The transmissive window is merged with the mirror element structure itself, formed as an integral part during the coating deposition process. This combines the sealing function and optical function into a single component, eliminating the need for separate glass plugs and reducing manufacturing complexity.
2Reliability
If glass plugs are used to seal the cavity, then the controlled environment is maintained, but the manufacturing cost increases
Solution Approach 1:
The glass plug component is extracted from the system and replaced with a coating-based solution. This eliminates material costs for glass plugs and reduces assembly complexity, thereby lowering overall manufacturing costs while maintaining environmental sealing.
Solution Approach 2:
The patent uses thin-film coating layers deposited directly on the mirror surface to create the transmissive window and sealing structure. These deposited layers provide a cost-effective alternative to expensive glass plugs, achieving the sealing function through economical coating materials and processes.
3Reliability
If glass plugs are used to seal the cavity, then contaminants are prevented from entering, but optical noise is introduced
Solution Approach 1:
The coating deposition creates different local properties: the transmissive window area remains uncoated or has different coating characteristics, while the surrounding areas have reflective or sealing coatings. This local differentiation allows light transmission through the window while maintaining sealing and reducing optical noise from peripheral reflections.
Solution Approach 2:
The patent converts the potential harm of open apertures (which would cause optical noise) into a beneficial transmissive window by selectively depositing coatings. The coating process transforms the harmful peripheral reflections into a controlled optical path through the window, eliminating noise while maintaining contaminant prevention.
4Ease of operation
If drilling holes in mirror elements is performed, then light entry is enabled, but the cavity size options are limited
Solution Approach 1:
The transmissive window dimensions and position are not fixed by mechanical drilling constraints but are defined by the flexible coating deposition process. This allows the window size and location to be dynamically adjusted based on cavity size requirements, enabling versatility across different cavity configurations without mechanical constraints.
Solution Approach 2:
The patent uses coating deposition parameters (such as mask positioning, deposition thickness, and pattern definition) to control the transmissive window characteristics. By changing these deposition parameters, the window can be adapted to various cavity sizes and configurations, providing versatility that mechanical drilling cannot achieve.
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 solution simplifies and cost-reduces the manufacturing of optical mirror elements, reduces optical noise, and allows for more flexible cavity sizes, enhancing the robustness and effectiveness of gas analyzers for in-field trace gas detection.
Implementation Method 1
a reflective coating layer on the first surface that defines a mirror surface
Implementation Method 2
the exposed portion of the first surface is coated with an anti-reflective coating
Data Source
AI summary
An optical mirror element includes an optically transmissive element having a first surface and a second surface, and a reflective coating layer on the first surface that defines a mirror surface. A first portion of the first surface does not include the reflective coating layer such that the first portion defines an optically transmissive window in the mirror surface. Q method of forming an optical mirror element having a window portion includes providing an optical element, masking a first portion of a first surface of the optical element, and thereafter applying a reflective coating to the first surface so as to define a reflective surface, wherein the masked portion defines a transmissive region in the reflective surface. The exposed portion of the first surface may be coated with an anti-reflective coating, either before or after the reflective coating is applied.