Curved-Edge Fabry-Perot Filter Structure for Noise and Stress Relief
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Solution Overview
Problem
In Fabry-Perot interferometers, the exposed outer surface of the sacrificial layer can cause noise in light output due to incident light with different wavelengths, and the flat orthogonal surface design can lead to stress concentration and potential damage, such as cracking, when the movable mirror moves.
Innovation Solution
A Fabry-Perot interference filter design with a continuously curved outer surface of the intermediate layer, where the edge on the substrate side is positioned outside the edge on the opposite side, is covered by the second layer, dispersing stress and preventing peeling and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional wideband interference filters are used, then a broad spectral range can be filtered, but the transmission edge becomes less steep and side lobes increase
Solution Approach 1:
The wideband interference filter is divided into multiple individual interference filter elements, each with a specific spectral transmission characteristic. These elements are arranged in series to collectively provide wideband filtering while maintaining steep transmission edges and reduced side lobes through individual element optimization.
Solution Approach 2:
Multiple interference filter elements with overlapping spectral characteristics are nested in series, where each element contributes to the overall spectral filtering. The cumulative effect of nested elements achieves both wide spectral coverage and sharp transmission edges that cannot be obtained by a single filter element.
2Manufacturing precision
If multiple individual interference filter elements are combined, then transmission edge steepness improves, but device complexity increases
Solution Approach 1:
The interference filter elements are designed with universal mounting configurations and standardized optical interfaces, allowing them to be easily assembled and aligned. This multi-functional design enables the same filter element structure to be used across different spectral ranges, reducing overall system complexity despite using multiple elements.
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 enhances the reliability of the Fabry-Perot interference filter by reducing noise in light output and preventing stress-related damage, ensuring stable operation and longevity.
Implementation Method 1
The dielectric mirror comprises a plurality of dielectric layers arranged in an alternating sequence of two different refractive indices
Implementation Method 2
the stack of dielectric layers forms a so-called dielectric mirror which, due to the stack of dielectric layers, has a defined reflection spectrum
Data Source
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AI summary
A Fabry-Perot interference filter (1) includes a substrate (11) that has a first surface (11a), a first laminate (22) that has a first mirror portion (31) disposed on the first surface (11a), a second laminate (24) that has a second mirror portion (32) facing the first mirror portion (31) via a gap (S) on a side opposite to the substrate (11) with respect to the first mirror portion (31), and an intermediate layer (23) that defines the gap (S) between the first laminate (22) and the second laminate (24). An outer surface (23b) of the intermediate layer (23) is curved such that an edge portion of the intermediate layer (23) on the substrate (11) side is positioned on an outer side of an edge portion of the intermediate layer (23) on the side opposite to the substrate (11) in a direction parallel to the first surface (11a). The second laminate (24) covers the outer surface (23b) of the intermediate layer (23).