Variable Wavelength Interference Filter for Parasitic Capacitance Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing variable wavelength interference filters face issues with parasitic capacitors due to electrically conductive materials in multi-layered films, leading to wavelength drift and manufacturing inconsistencies that affect the accuracy of transmitted wavelengths.
Innovation Solution
The filter design includes optically stacked bodies with end-surface layers electrically coupled to electrodes, separating reflective and electrode regions to suppress parasitic capacitors, and a coupling section to absorb manufacturing inconsistencies, ensuring precise gap control and wavelength accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If thin layers of electrically conductive material are used in the multi-layered films, then the reflective performance is improved, but parasitic capacitors increase causing wavelength drift
Solution Approach 1:
The patent segments the multi-layered film structure into distinct functional regions: a reflective region with conductive thin layers for optical performance, and an electrode region with separate electrode structures for actuation. This segmentation isolates the conductive materials to specific areas, reducing unwanted parasitic capacitance while maintaining reflective performance.
Solution Approach 2:
The patent introduces an intermediary insulating layer between the conductive thin layers of the multi-layered film and the electrode structures. This intermediary layer acts as a mediator that electrically isolates the conductive materials from the electrodes, preventing parasitic capacitor formation while allowing the system to maintain both optical and electrical functions.
2Reliability
If the multi-layered films are removed from non-reflective regions, then parasitic capacitors are reduced, but manufacturing inconsistency of gap size increases
Solution Approach 1:
The patent segments the device into distinct functional regions with different structures: the reflective region contains the multi-layered film for optical performance, while the electrode region contains the actuator electrodes. This regional segmentation allows each area to be optimized for its specific function without compromising the other.
Solution Approach 2:
The patent applies local quality by giving different structural characteristics to different regions of the device. The reflective region has the complete multi-layered film structure for optimal optical performance, while the electrode region has a simplified structure with separate electrodes to minimize parasitic capacitance. Each region's structure is tailored to its specific functional requirements.
3Device complexity
If electrodes are stacked directly on the multi-layered films, then the device structure is simplified, but parasitic capacitors increase causing control troubles
Solution Approach 1:
The patent introduces an insulating intermediary layer between the electrode structures and the multi-layered film. This intermediary layer maintains the simplified stacked structure while preventing direct electrical contact, thereby eliminating parasitic capacitor formation and ensuring accurate gap control.
Solution Approach 2:
The insulating intermediary layer is applied locally in the electrode region where electrodes contact or approach the multi-layered film structure. This localized application provides electrical isolation exactly where needed without adding complexity to other regions of the device.
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 effectively suppresses parasitic capacitors, allowing for precise control of the gap between reflective regions, enhancing wavelength accuracy and reducing manufacturing inconsistencies.
Implementation Method 1
a coupling film disposed between the coupling region of the first multi-layered film and the coupling region of the second multi-layered film and configured to couple the first substrate and the second substrate to each other
Implementation Method 2
an electrostatic actuator configured to displace the first substrate toward the second substrate
Implementation Method 3
a capacitance detector used to detect the gap
Implementation Method 4
an optically stacked body stacked at the first substrate or the second substrate
Implementation Method 5
a first reflective film provided at the first substrate; a second reflective film provided at the second substrate
Data Source
AI summary
A variable wavelength interference filter includes: a first substrate; a first multi-layered film provided at the first substrate; a first electrode portion provided at an electrode region of the first multi-layered film; a second substrate disposed so as to be opposed to the first substrate; a second multi-layered film provided at the second substrate; a second electrode portion provided at an electrode region of the second multi-layered film so as to be opposed to the first electrode portion; and a coupling section disposed between a coupling region of the first multi-layered film and a coupling region of the second multi-layered film. A reflective region of the first multi-layered film and a reflective region of the second multi-layered film are disposed so as to be opposed to each other with a gap being interposed between them. The first multi-layered film and the second multi-layered film each include an optically stacked body and an end-surface layer formed at an end surface of the optically stacked body. At least a portion of the end-surface layer is electrically coupled to the first electrode portion or the second electrode portion.