Variable Wavelength Interference Filter Vacuum Sealing
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Solution Overview
Problem
The variable wavelength interference filter in existing technologies faces insufficient responsiveness due to air resistance issues, which hinder the movement of the movable mirror during operation.
Innovation Solution
A variable wavelength interference filter design that includes a light-transmissive substrate configuration with a movable portion and electrostatic actuator, where internal spaces are maintained at a reduced pressure by sealing penetration holes with a sealant, reducing air resistance and enhancing mirror responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the movable mirror is operated in atmospheric pressure, then the device structure is simple, but air resistance reduces the responsiveness of the movable mirror
Solution Approach 1:
The patent applies vacuum (inert environment) inside the etalon housing to eliminate air resistance. The internal space containing the movable mirror is evacuated to create a vacuum environment, allowing the movable mirror to respond quickly without air drag, while the exterior remains at atmospheric pressure for simple operation and bonding.
2Ease of manufacture
If the internal space is sealed at atmospheric pressure, then bonding is easier, but air resistance acts on the movable mirror during operation
Solution Approach 1:
The patent performs bonding at atmospheric pressure before evacuation. The etalon housing is first bonded to the substrate at atmospheric pressure when bonding is easiest, then the internal space is evacuated to create vacuum. This preliminary bonding action resolves the contradiction between ease of manufacture and responsiveness.
3Speed
If a penetration hole is provided for vacuum evacuation, then responsiveness improves, but the internal space becomes vulnerable to contamination
Solution Approach 1:
The patent extracts the vacuum evacuation function to a separate penetration hole that is distinct from the bonding interface. The penetration hole is provided in the etalon housing at a position away from the bonded surface, allowing vacuum evacuation without compromising the bonding integrity or internal space sealing.
4Productivity
If the movable mirror moves quickly, then wavelength selection is faster, but air resistance opposes the motion
Solution Approach 1:
The patent creates a vacuum (inert environment) in the internal space to eliminate air resistance that opposes the motion of the movable mirror. This allows the mirror to move quickly for fast wavelength selection without the harmful effect of air drag.
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 improves the responsiveness of the movable mirror by minimizing air resistance, allowing for quicker and more precise wavelength selection and emission of light, while also enabling bonding at atmospheric pressure with high-quality substrates using plasma polymerized films or metal films.
Implementation Method 1
an electrostatic actuator which has a pair of displacement electrodes facing each other, on the surfaces facing each other of the first substrate and the second substrate, and displaces the movable portion in the substrate thickness direction by electrostatic attraction as a predetermined voltage is applied to the displacement electrodes
Implementation Method 2
A penetration hole through which the first internal space and the second internal space are connected to an exterior space outside of the filter is formed. The penetration hole is sealed with a sealant which tightly closes the first internal space and the second internal space in a reduced-pressure state below atmospheric pressure.
Implementation Method 3
The penetration hole is sealed with a sealant which tightly closes the first internal space and the second internal space in a reduced-pressure state below atmospheric pressure
Implementation Method 4
a spectral filter is known which acquires light of a specific wavelength from incident light by reflecting light between a pair of reflection mirrors, transmitting light of a specific wavelength and canceling light of other wavelengths by interference
Data Source
AI summary
A variable wavelength interference filter includes a first substrate having a fixed mirror, a second substrate bonded to the first substrate and having a movable portion and a movable mirror fixed to the movable portion, a third substrate bonded to the second substrate on the side opposite to the first substrate, and an electrostatic actuator which displaces the movable portion in a substrate thickness direction, wherein a penetration hole connecting a light exiting-side space between the first substrate and the second substrate and a light incident-side space between the second substrate and the third substrate to a space outside the filter is formed, and the penetration hole is sealed with a sealant which tightly closes each space in a reduced-pressure state.