Coupled-Oscillator Microscanner for Rectangular Lissajous Illumination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gimbal-less microscanners with coupled vibration axes struggle to achieve planar Lissajous illumination due to rapid convergence of resonant frequencies, resulting in elliptical projections.
Innovation Solution
A gimbal-less microscanner with a deflection unit and a control device that adjusts oscillations individually to maintain a minimum frequency separation between axes, utilizing an amplitude-dependent mutual coupling and dynamic control to ensure rectangular illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a gimbal-less microscanner with coupled vibration axes is used, then installation space is reduced, but the resonant frequencies rapidly converge resulting in elliptical projections instead of planar Lissajous illumination
Solution Approach 1:
The patent applies dynamics by making the operating frequencies of the two vibration axes dynamically adjustable and independent from each other. The control device can set the first operating frequency of the first vibration axis and the second operating frequency of the second vibration axis independently, allowing the system to maintain planar Lissajous figures despite the inherent coupling in gimbal-less design. This dynamic frequency control prevents the rapid convergence that would otherwise occur, resolving the contradiction between compact space and proper projection shape.
2Shape
If the oscillation axes are completely decoupled using a gimbal suspension, then planar Lissajous illumination is achieved, but the device complexity and installation space increase
Solution Approach 1:
The patent extracts the decoupling function from the mechanical gimbal suspension structure and transfers it to the control system. Instead of using a complex gimbal mechanism to physically decouple the axes, the invention uses a control device that independently regulates the operating frequencies of the two vibration axes. This extraction of the decoupling function from mechanical components to the control domain simplifies the overall device structure while maintaining the desired planar illumination pattern.
3Ease of operation
If the resonant frequencies of the two vibration axes are allowed to converge, then the system operates more simply, but the projection becomes elliptical rather than rectangular
Solution Approach 1:
The patent implements feedback control where the control device continuously monitors and independently adjusts the operating frequencies of the first and second vibration axes. By providing independent frequency control with feedback regulation, the system can maintain the necessary frequency separation to produce rectangular planar Lissajous figures while keeping the operation simple. The feedback mechanism ensures that even if the axes are coupled, the frequencies remain properly separated to avoid elliptical projections.
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
Enables consistent, uniform, and substantially rectangular illumination despite coupled oscillations, reducing installation space and maintaining frequency ratios across temperature variations, with improved tuning range and resilience to disturbances.
Implementation Method 1
The spring device is designed to provide an amplitude-dependent mutual coupling between the first and second oscillations
Implementation Method 2
a deflection element ("mirror") is used to modulate the direction of deflection of an incident electromagnetic beam
Implementation Method 3
The control device comprises a first control loop configured to regulate the first and/or second control frequency based on a measured phase of the deflection unit's oscillations, ensuring that the maximum amplitude of the oscillations remains within the deflection unit's resonance range
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Disclosed is a projection system for projecting Lissajous figures onto an observation field, comprising a microscanner. The microscanner has a deflection unit with a deflection element for deflecting an incident electromagnetic beam, a supporting structure and a spring device by means of which the deflection element is mounted gimballess on the supporting structure such that it can perform simultaneously, relative to the supporting structure, a first rotational oscillation about a first oscillation axis and a second rotational oscillation about a second oscillation axis perpendicular to the first oscillation axis in order to produce a non-linear Lissajous projection by deflecting an electromagnetic beam incident on the deflection element during the simultaneous oscillations. The microscanner also has a control device for actuating a drive device for driving the deflection unit such that a respective drive effect can be configured individually in relation to at least one of the oscillations of the deflection element. In addition, the spring device is configured so as to provide a mutual coupling between the oscillations which is dependent on the amplitude. The control device is also set up to actuate the drive device on the basis of at least one detected state variable of the first oscillation in order to generate a drive effect on the second oscillation by influencing at least one state variable of the second oscillation, which counteracts falling below a predefined minimum frequency variation between the respective instantaneous oscillation frequencies of the first and second oscillation.