Optical Module Variable Wavelength Filter Resonance Drive
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Solution Overview
Problem
Existing optical modules with variable wavelength interference filters require high voltages to vary the gap dimension between reflecting films, leading to high current and power consumption, which is undesirable for energy-efficient applications.
Innovation Solution
An optical module configuration that includes a variable wavelength interference filter with an electrostatic actuator driven by a periodic drive voltage, utilizing both electrostatic force and restoring force to vary the gap dimension, and a light receiver to detect light intensity at specific gap dimension timings, allowing for reduced voltage operation and eliminating the need for a step-up circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a high voltage is applied to the electrostatic actuator to vary the gap dimension between reflecting films, then the gap dimension can be effectively varied, but the current consumption and power consumption increase
Solution Approach 1:
The patent applies periodic drive voltage to the electrostatic actuator to induce vibration in the variable wavelength interference filter. This vibration causes periodic variation in the gap dimension between the reflecting films, enabling the system to scan through different wavelengths without requiring large static voltage changes. The vibrational mechanism allows effective gap variation with lower voltage amplitude.
Solution Approach 2:
The patent employs periodic drive voltage applied to the electrostatic actuator to create periodic variation in the gap dimension. This periodic action allows the system to achieve wavelength scanning through oscillation rather than requiring large static voltage steps, thereby reducing power consumption while maintaining effective gap control capability.
2Use of energy by moving object
If the voltage applied to the electrostatic actuator is reduced to lower power consumption, then current and power usage decrease, but the ability to vary the gap dimension effectively is compromised
Solution Approach 1:
By utilizing vibration induced by periodic voltage, the system achieves precise gap dimension variation through controlled oscillation. The vibrational approach allows the gap to sweep through a precise range of dimensions during each vibration cycle, maintaining measurement precision even though the peak voltage is reduced compared to static actuation methods.
Solution Approach 2:
The patent incorporates a gap detector to monitor the actual gap dimension between the reflecting films. This feedback information is used to control the timing of light intensity detection, ensuring that measurements are taken at the appropriate phase of the vibration cycle. This feedback mechanism maintains gap dimension precision and measurement accuracy despite the reduced voltage operation.
3Ease of operation
If a step-up circuit is added to provide higher voltage for the electrostatic actuator, then the gap dimension can be varied effectively, but the device complexity increases
Solution Approach 1:
The periodic drive voltage approach allows the system to achieve effective gap variation through oscillation rather than requiring high static voltage. This eliminates the need for step-up circuits or voltage multiplication stages, simplifying the overall circuit configuration while maintaining the capability to vary the gap dimension between reflecting films for wavelength tuning.
4Ease of operation
If the variable wavelength interference filter is displaced only by electrostatic actuator force, then direct control is achieved, but higher voltage is required compared to utilizing restoring force
Solution Approach 1:
The periodic drive voltage creates vibration that utilizes the restoring force of the variable wavelength interference filter structure. During each vibration cycle, the filter is displaced from its equilibrium position and then returns due to its inherent restoring force. This approach effectively combines the electrostatic actuator force with the mechanical restoring force, achieving gap variation with lower voltage amplitude and reduced power consumption compared to purely electrostatic displacement.
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 enables the measurement of light intensity with lower voltage consumption, reducing current and power usage while maintaining accurate resonance of the variable wavelength interference filter, suitable for miniaturization and battery-powered devices.
Implementation Method 1
an electrostatic actuator configured to change a gap dimension between the pair of reflecting films
Implementation Method 2
it is possible to displace the variable wavelength interference filter using not only the force generated by the electrostatic actuator, but also the restoring force for biasing the variable wavelength interference filter once deformed to return to the original shape
Implementation Method 3
a light receiver (photodiode) configured to receive light output from the variable wavelength interference filter
Data Source
AI summary
An optical module includes a variable wavelength interference filter provided with a pair of reflecting films, and an electrostatic actuator configured to change a gap dimension between the pair of reflecting films, a driver configured to apply a periodic drive voltage to the electrostatic actuator, a gap detector configured to detect a gap dimension between the pair of reflecting films, and a light receiver configured to receive light from the variable wavelength interference filter. The light reception signal from the light receiver is detected at a predetermined timing from a detection timing of one of a maximum value and a minimum value of the gap dimension detected by the gap detector.