Micromechanical Deflectable Element Control via Contactless Position Detection
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Solution Overview
Problem
Micromechanically manufactured deflectable elements experience restricted deflection due to the electrostatic pull-in effect, limiting their usable range and requiring high drive voltages, which can lead to damage.
Innovation Solution
Incorporating a contactless detection system, such as optical, capacitive, or piezoelectric sensors, to monitor deflection positions and control the electrostatic voltage, preventing the pull-in effect by deactivating the voltage when a preset deflection is reached, allowing for larger deflections without mechanical damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the deflectable element is deflected closer to the counter-electrode to increase the deflection range, then the deflection range is improved, but the electrostatic pull-in effect occurs causing system instability and potential damage
Solution Approach 1:
The patent applies preliminary action by detecting the deflection position before the pull-in effect occurs and preemptively switching off the electrostatic drive voltage. The detector monitors the deflection angle or position, and when a predetermined threshold is approached, the control unit deactivates the voltage before instability can occur, allowing the element to be deflected closer to the counter-electrode safely.
Solution Approach 2:
The patent implements feedback by using a detector to continuously monitor the deflection position of the element and feeding this information back to the control unit. Based on this feedback signal, the control unit adjusts or switches off the drive voltage in real-time, preventing the pull-in effect while maximizing the usable deflection range.
2Reliability
If the distance between the deflectable element and counter-electrode is increased to avoid the pull-in effect, then the reliability is improved, but the deflection range is reduced and higher drive voltages are required
Solution Approach 1:
By switching off the voltage preemptively before the pull-in effect occurs, the patent allows the element to utilize a larger portion of the available distance (up to 2/3 instead of 1/3) without requiring increased electrode spacing. This reduces the overall distance needed while maintaining stability, thereby lowering the required drive voltage.
Solution Approach 2:
The patent changes the operational parameter by dynamically adjusting the drive voltage based on the deflection position. Instead of maintaining a constant high voltage to prevent pull-in, the voltage is reduced or switched off when approaching the critical threshold, optimizing energy efficiency while enabling larger deflections.
3Length of moving object
If the maximum deflection is increased to utilize more of the available distance, then the deflection range is improved, but the required voltage potential difference increases to several hundred volts
Solution Approach 1:
The patent applies preliminary action by switching off the electrostatic voltage before the element reaches the point where maximum deflection would require excessive voltage. This allows the element to be deflected to a larger extent (up to 2/3 of available distance) while keeping the voltage potential difference at manageable levels, avoiding the need for several hundred volts.
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 a significantly increased deflection range while reducing the required voltage potential and preventing damage, allowing for more efficient and controlled operation of deflectable elements.
Implementation Method 1
a beam of a suitable light source, for example of a laser diode, is directed onto a reflective surface of the deflectable element and, on a preset deflection position of the deflectable element, the beam reflected by the surface impacts the optical detector
Implementation Method 2
If a potential difference of the electrical voltage is applied between the plate and one of the two counter-electrodes 3a or 3b, the plate is deflected in the direction of the respective counter-electrode
Implementation Method 3
the restoring force of the spring elements prevents a much larger deflection and, with the exception of an inertia-induced further deflection in the direction of the respective counter-electrode, prevents a deflection which would result in damage
Data Source
AI summary
The invention relates to an apparatus and to a method for controlling or regulating the deflection of micromechanically manufactured deflectable elements which, driven electrostatically, are deflected in an oscillating manner. It is the object of the invention to provide a possibility with which a much larger deflection range can be utilized and in so doing the required voltage potential difference for the electrostatic drive of a deflection can be kept small and the occurrence of the pull-in effect can be avoided. In accordance with the invention, a deflectable element is present which is held at a frame element by at least one spring element and which can be deflected using an electrostatic drive. The deflection can be achieved by means of at least one counter-electrode and the deflectable element usable as an electrode. In addition, at least one detector is present which is suitable for the contactless detection of at least one deflection position and which is connected to an electronic evaluation and control unit to influence the electrical voltage potential difference between the deflectable element and the counter-electrode(s) in dependence of a specific deflection position.