Optical Filter Device With Annular Recessed Portion
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Solution Overview
Problem
Traditional optical filter devices with variable-wavelength interference filters face issues due to impaired parallelism of the base substrate, leading to local contact and reduced resolution when joining the filter, which affects spectroscopic accuracy.
Innovation Solution
An optical filter device design featuring a light interference filter with a first and second substrate, where the second substrate has an annular recessed portion and the base substrate has a light transmission hole with its outer peripheral edge facing the recessed portion, allowing horizontal fixation and preventing local contact, along with a gap change unit to adjust the wavelength, and an adhesive layer for stress reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a light transmission hole is provided in the base substrate, then light transmission is enabled, but parallelism of the base substrate is impaired due to curvature or protrusion near the outer peripheral edge
Solution Approach 1:
An annular recessed portion is introduced as an intermediary structure between the light transmission hole and the light interference filter. This recessed portion acts as a mediator that prevents direct contact between the curved/protruding peripheral edge of the light transmission hole and the joining surface of the light interference filter, thereby maintaining parallelism while preserving light transmission capability.
Solution Approach 2:
The base substrate is segmented into functional zones: a light transmission region with the light transmission hole for optical passage, and an annular recessed portion surrounding it for mechanical support and parallelism maintenance. This segmentation allows each zone to fulfill its specific function without compromising the other.
2Ease of manufacture
If the base substrate with impaired parallelism is joined to the light interference filter, then assembly is achieved, but local contact occurs at curving or protruding parts preventing horizontal fixture
Solution Approach 1:
The annular recessed portion serves as an intermediary structure that decouples the joining interface from the defective peripheral regions. By positioning the outer peripheral edge of the light transmission hole to face the recessed portion rather than directly contacting the filter, the mediator structure enables assembly while preserving measurement precision.
Solution Approach 2:
Different regions of the base substrate are given different functional qualities: the central region provides light transmission, the annular recessed portion provides mechanical support and alignment, while deliberately excluding the defective peripheral edges from the joining interface. This local differentiation ensures that only high-quality regions participate in the precision-critical joining operation.
3Strength
If the outer peripheral edge of the light transmission hole directly contacts the joining surface, then structural support is maximized, but stray light is generated and resolution is lowered
Solution Approach 1:
The annular recessed portion acts as a mediator between the light transmission hole and the light interference filter. It provides structural support through its annular geometry while preventing direct contact that would cause stray light, thereby maintaining both strength and measurement precision.
Solution Approach 2:
The curvature and protrusion defects near the outer peripheral edge, which would normally cause harm through local contact and stray light, are converted into a benefit by positioning them within the annular recessed portion. The recessed structure transforms these defective regions into a supportive annular framework that excludes the defects from the critical joining interface.
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 configuration ensures high spectroscopic accuracy by preventing local contact and stray light, enabling precise detection of light with a desired target wavelength, enhancing the resolution and accuracy of the optical filter device.
Implementation Method 1
a first reflection film that is provided on the first substrate, reflects a part of incident light and transmits a part of the incident light
Implementation Method 2
a second reflection film that is provided on the second substrate, faces the first reflection film, reflects a part of incident light and transmits a part of the incident light
Implementation Method 3
variable-wavelength interference filter
Data Source
AI summary
An optical filter device has a light interference filter and a casing. The light interference filter has a fixed substrate, a movable substrate joined to the fixed substrate, a fixed reflection film provided on the fixed substrate, and a movable reflection film provided on the movable substrate. The casing has a base substrate and a lid that forms an internal space with the base substrate. The movable substrate has a holding portion provided on a surface opposite to the fixed substrate, outside a light interference region, as viewed in a plan view. The base substrate has a light transmission hole corresponding to a light transmission region. An outer peripheral edge of the light transmission hole faces the holding portion. The surface opposite to the fixed substrate of the movable substrate is joined to the base substrate.