Variable Wavelength Interference Filter Electrode Asymmetry
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Solution Overview
Problem
Variable wavelength interference filters face accuracy degradation in gap control due to bonding misalignment during the manufacturing process, leading to reduced performance and accuracy in light transmission.
Innovation Solution
The filter design includes electrodes positioned outside the optical interference region, with specific edge configurations to maintain the electrostatic actuator's area and prevent overlap, ensuring consistent electrostatic attractive force and accurate gap control even with minor misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the first electrode and second electrode are disposed so as to be opposed to each other to form an electrostatic actuator, then the gap control accuracy is improved, but the manufacturing precision deteriorates due to sensitivity to bonding misalignment
Solution Approach 1:
The patent applies asymmetry by making the first electrode wider than the second electrode in the plan view. Specifically, the first electrode has a first width dimension that is larger than the second electrode's second width dimension. This asymmetric configuration ensures that even when bonding misalignment occurs, the electrodes maintain sufficient overlap area to function as an effective electrostatic actuator, thereby tolerating manufacturing variations while preserving gap control accuracy.
2Force
If the electrodes are positioned to maximize overlap area for electrostatic actuation, then the electrostatic force is improved, but the device complexity increases due to precise positioning requirements
Solution Approach 1:
The patent applies preliminary action by designing the electrode configuration in advance with the first electrode wider than the second electrode. This pre-designed asymmetric structure ensures that sufficient overlap area is maintained even under typical bonding misalignment conditions, eliminating the need for complex positioning mechanisms or post-processing adjustments while still achieving effective electrostatic actuation.
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 maintains the electrostatic actuator's characteristics and accuracy of gap control, preventing performance degradation and ensuring precise light transmission with desired target wavelengths.
Implementation Method 1
by the first electrode and the second electrode constituting an electrostatic actuator with the regions opposed to each other, and applying a voltage between the electrodes, it becomes possible to vary the inter-reflecting film gap due to the electrostatic attractive force
Implementation Method 2
a first reflecting film provided to the first substrate, a second reflecting film provided to the second substrate, and opposed to the first reflecting film via an inter-reflecting film gap
Implementation Method 3
there is disposed a first electrode to be bilaterally symmetric with respect to a region for transmitting the light
Data Source
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AI summary
A variable wavelength interference filter includes a stationary substrate including a stationary reflecting film and a stationary electrode, and a movable substrate including a movable reflecting film and a movable electrode, the stationary electrode and the movable electrode are disposed outside an optical interference region where the stationary reflecting film and the movable reflecting film overlap each other in a filter plan view, an inner peripheral edge of the stationary electrode is located nearer to the optical interference region than an outer peripheral edge of the movable electrode, and an outer peripheral edge of the stationary electrode is located further from the optical interference region than an outer peripheral edge of the movable electrode.