Optical Device Nonlinearity Relaxation Spring Torsion Bar
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Solution Overview
Problem
The optical device experiences nonlinearity in torsional deformation of the torsion bar due to its bent configuration, which deteriorates the control characteristic of the movable portion and limits the movement amount, as the nonlinearity worsens with increased movement.
Innovation Solution
Incorporating a nonlinearity relaxation spring between the torsion bar and the movable portion, configured to have a smaller deformation in the direction perpendicular to the movement direction and a larger deformation in a direction parallel to the movement direction, along with a second comb electrode disposed along the outer edge of the movable portion to efficiently utilize electrostatic force and increase movement, while suppressing torsional deformation nonlinearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the movable portion moves along the movement direction, then the optical path length is modulated, but nonlinearity occurs in the torsional deformation of the torsion bar which deteriorates the control characteristic
Solution Approach 1:
A nonlinearity relaxation spring is introduced as an intermediary element between the torsion bar and the movable portion. This spring absorbs the nonlinearity in torsional deformation through its own elastic characteristics, allowing the torsion bar to deform more linearly while still achieving the required movement range. The relaxation spring acts as a buffer that decouples the nonlinear torsional behavior from the control system.
Solution Approach 2:
The patent modifies the elastic support portion configuration to include the nonlinearity relaxation spring, changing the mechanical parameters of the support system. By carefully selecting the spring constant and pre-compression force of the relaxation spring, the overall system achieves improved linearity in the torsional deformation characteristics while maintaining the required movement amplitude.
2Length of moving object
If the movement amount of the movable portion is increased, then the optical path length modulation range is extended, but nonlinearity in torsional deformation easily occurs
Solution Approach 1:
The nonlinearity relaxation spring serves as a mediator that enables larger movement amounts while maintaining torsional deformation linearity. As the movable portion travels through a larger range, the relaxation spring progressively engages to absorb nonlinearities, allowing extended optical path modulation without compromising the stability of the torsional deformation characteristics.
Solution Approach 2:
The relaxation spring is pre-configured with appropriate pre-compression and stiffness characteristics to cushion against nonlinear torsional deformation before it significantly affects the system. This beforehand cushioning ensures that even when the movable portion achieves large movement amounts, the torsional deformation remains within linear ranges.
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
The solution effectively suppresses torsional deformation nonlinearity and increases the movement amount of the movable portion, maintaining control characteristic stability even with increased movement, by efficiently using electrostatic force and optimizing the deformation characteristics of the nonlinearity relaxation spring.
Implementation Method 1
a first comb electrode which is provided in the base and includes a plurality of first comb fingers; and a second comb electrode which is provided in the elastic support portion and includes a plurality of second comb fingers alternately arranged with the plurality of first comb fingers
Implementation Method 2
a nonlinearity relaxation spring connected between the torsion bar and the movable portion, wherein the nonlinearity relaxation spring is configured so that a deformation amount of the nonlinearity relaxation spring around the second direction is smaller than a deformation amount of the torsion bar around the second direction
Data Source
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AI summary
An optical device includes an elastic support portion which supports a movable portion so that the movable portion is movable along a first direction, a first comb electrode which includes a plurality of first comb fingers, and a second comb electrode which includes a plurality of second comb fingers. The elastic support portion includes a torsion bar which extends along a second direction perpendicular to the first direction and a nonlinearity relaxation spring which is connected between the torsion bar and the movable portion. The nonlinearity relaxation spring is configured so that a deformation amount of the nonlinearity relaxation spring around the second direction is smaller than a deformation amount of the torsion bar around the second direction and a deformation amount of the nonlinearity relaxation spring in a third direction perpendicular to the first direction and the second direction is larger than a deformation amount of the torsion bar in the third direction while the movable portion moves in the first direction. The second comb electrode is disposed along an outer edge of the movable portion.