Variable Wavelength Interference Filter Mounting via Stepped Light Passage
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Solution Overview
Problem
The existing optical filter devices with variable wavelength interference filters face issues due to warpage or projection near the light passage holes, leading to degraded parallelism of the base substrate, which affects the accurate mounting and resolution of the filter.
Innovation Solution
The electronic device incorporates a base substrate with a laminated body and a light transmissive substrate, where the second opening of the light passage hole is larger than the first opening, preventing warpage and ensuring accurate mounting of the functional element, and the light transmissive substrate is positioned to prevent contact with the functional element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light passage hole is formed in the base substrate, then light can pass through to the functional element, but warpage or projection occurs near the outer circumferential edge, degrading parallelism
Solution Approach 1:
The patent applies local quality by creating a stepped structure in the light passage hole, where the first opening at the functional element side has a different area than the second opening at the opposite side. This localized variation in opening size specifically addresses the warpage issue at the outer circumferential edge while maintaining light transmission through the hole.
Solution Approach 2:
The light passage hole is designed with asymmetric opening sizes - the first opening near the functional element has a different area than the second opening at the opposite side. This asymmetric configuration compensates for the warpage that occurs during manufacturing, allowing the base substrate to maintain overall parallelism while still enabling effective light transmission.
2Ease of manufacture
If the base substrate with degraded parallelism is bonded to the variable wavelength interference filter, then assembly is completed, but the filter fails to be fixed horizontally, degrading resolution
Solution Approach 1:
The stepped structure in the light passage hole is designed in advance to counteract the warpage that occurs during manufacturing. By pre-compensating for the expected deformation through the asymmetric opening design, the base substrate maintains sufficient parallelism to ensure accurate horizontal fixation of the variable wavelength interference filter, preventing resolution degradation.
3Manufacturing precision
If the light passage hole is made larger to prevent warpage, then mounting accuracy is improved, but the structure becomes more complex
Solution Approach 1:
The light passage hole is segmented into two distinct openings with different areas - a first opening at the functional element side and a second opening at the opposite side. This segmentation allows each opening to serve its specific function: the first opening facilitates light transmission while the larger second opening compensates for warpage, achieving mounting accuracy without requiring a uniformly complex structure throughout.
Data Source
AI summary
An electronic device includes a variable wavelength interference filter, and a package adapted to house the variable wavelength interference filter. The package includes a base substrate provided with a light passage hole through which light passes, and a base substrate side light transmissive substrate adapted to block the light passage hole and having a light transmissive property. The base substrate is formed of a laminated body having a plurality of layers stacked on each other, and the light passage hole is formed so that a second opening located on an opposite side to the variable wavelength interference filter is larger in area than a first opening located on the variable wavelength interference filter side.