Wavelength Variable Interference Filter Gap Optimization
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Solution Overview
Problem
Existing wavelength variable interference filters face challenges in achieving high driving reproducibility due to variations in the gap dimension between reflection films, which affects the precision of output wavelengths.
Innovation Solution
A wavelength variable interference filter design with a gap changing unit that adjusts the gap dimension between reflection films, where the first and second reflection films are optimized such that the gap dimension for outputting a specific wavelength is smaller than the baseline, improving reproducibility and spectral precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If feedback control is performed on the gap dimension between reflection films, then the gap dimension can be controlled, but variations in the gap dimension increase as the gap dimension increases, reducing driving reproducibility
Solution Approach 1:
The patent optimizes the relationship between the peak center wavelengths (λ1, λ2) of the two reflection films and the measurement center wavelength (λ0) to minimize the required gap dimension. By carefully selecting and adjusting the optical parameters of the reflection films, the design achieves smaller gap dimensions that are less sensitive to fabrication variations, thereby improving driving reproducibility while maintaining wavelength control precision
2Adaptability or versatility
If the gap dimension between reflection films is increased, then the filter can operate at different wavelengths, but variations in the gap dimension increase, reducing driving reproducibility
Solution Approach 1:
The patent employs asymmetric design in the reflection film configuration, where the two reflection films have different peak center wavelengths (λ1 and λ2) that are strategically positioned relative to the measurement center wavelength (λ0). This asymmetric wavelength configuration allows the system to achieve wavelength tuning while operating at smaller, more stable gap dimensions, thus maintaining driving reproducibility across the tuning range
3Ease of manufacture
If the reflection films are designed with asymmetrical reflection characteristics to simplify spectral characteristic design, then design ease is improved, but driving reproducibility based on gap dimension is not improved
Solution Approach 1:
The patent goes beyond simple asymmetric design by optimizing the specific parameter relationship between the reflection film peak center wavelengths (λ1, λ2) and the measurement center wavelength (λ0). This parameter optimization ensures that the asymmetric configuration not only simplifies spectral characteristic design but also inherently provides smaller, more stable gap dimensions that improve driving reproducibility
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 optimized design reduces variations in the gap dimension, enhancing driving reproducibility and spectral precision by ensuring the gap dimension is minimized for desired wavelengths, leading to high-precision output of light.
Implementation Method 1
A Fabry-Perot etalon interference filter that includes a pair of reflection films facing each other
Data Source
AI summary
A wavelength variable interference filter includes a fixed reflection film, a movable reflection film, and an actuator that changes a gap between the films. A wavelength of output light is first wavelength λα. A center wavelength in a target wavelength region is measurement center wavelength λ0. A peak center wavelength in reflection characteristics of the movable reflection film is first center wavelength λ1. A peak center wavelength in reflection characteristics of the fixed reflection film is second center wavelength λ2. The gap between the films when light of the first wavelength λα is transmitted is dα(λ1 , λ2). When a pair of optical films face each other, a center wavelength in reflection characteristics of the pair is the measurement center wavelength λ0, and the light of the first wavelength λα is outputted, the gap between the pair of optical films is dα(λ0, λ0). Further, dα(λ1, λ2)<dα(λ0, λ0).