Optical Filter Non-Uniform Gap Design for Wavelength Consistency
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Solution Overview
Problem
Existing optical filters with uniform gap dimensions between reflection films suffer from variations in transmission wavelength due to differing incident angles of light, leading to inconsistent performance across the light transmission region.
Innovation Solution
The optical filter design features a non-uniform gap dimension between reflection films, with a smaller gap at the center and increasing radially outward, adjusted by a stress film to maintain consistent transmission wavelengths across the light transmission region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform gap dimension is used between reflection films, then the manufacturing is simplified, but the transmission wavelength varies due to different incident angles of light
Solution Approach 1:
The gap dimension is made non-uniform with a specific gradient distribution: smaller at the center and larger at the outer peripheral portions of the light transmission region. This local variation in gap dimension compensates for the angle-dependent wavelength shift, ensuring that light at different incident angles transmits at the same wavelength.
Solution Approach 2:
The gap dimension parameter is changed from uniform to non-uniform distribution. By adjusting the gap dimension as a function of radial position (smaller at center, larger at periphery), the optical path difference is compensated for different incident angles, maintaining consistent transmission wavelength across the aperture.
2Manufacturing precision
If the gap dimension increases from center to periphery, then transmission wavelength consistency is improved, but the manufacturing complexity increases
Solution Approach 1:
The gap dimension follows a curved gradient pattern rather than abrupt changes. The gap increases gradually from the center toward the periphery, creating a smooth transition that simplifies manufacturing compared to discrete stepped structures while achieving the desired optical compensation.
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 ensures consistent transmission wavelengths across the light transmission region, suppressing variations and maintaining peak transmittance at a desired wavelength regardless of incident angle, thereby improving the filter's spectral separation and imaging accuracy.
Implementation Method 1
multiple reflection of light is caused between the pair of reflection films
Implementation Method 2
transmitted lights having a predetermined wavelength interfere to strengthen one another
Implementation Method 3
a stress film provided on the first substrate, wherein the stress film applies a stress to the first substrate to deform the first reflection film toward the second reflection film
Data Source
AI summary
An optical filter includes a reflection film and a reflection film placed to face the reflection film via a gap. As seen from a direction in which the reflection films face, a range in which the reflection films overlap forms a light transmission region, and a dimension of the gap in a center portion of the light transmission region is smaller than a dimension of the gap in an outer peripheral portion outside of the center portion within the light transmission region.