Electrode Arrangement for Drift-Free Micromechanical Elements
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Micromechanical elements in existing technologies experience drift over time due to electrical charging from incident electromagnetic radiation, leading to instability in the force ratio and deflection, requiring frequent recalibration and affecting CMOS circuit activation.
Innovation Solution
Arranging electrodes underneath micromechanical elements on the side not directly exposed to electromagnetic radiation, with each electrode serving multiple elements, and designing them to cover gaps between adjacent elements to prevent radiation-induced charging, while using larger electrodes to increase electrostatic force with lower voltages and stiffer torsion spring elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrodes are arranged below micromechanical elements to enable individual control, then precise deflection control is achieved, but electrical charging from incident electromagnetic radiation causes deflection drift over time
Solution Approach 1:
A conductive layer is introduced as an intermediary between the incident electromagnetic radiation and the substrate. This conductive layer captures the electrical charge generated by radiation before it can accumulate on the substrate and affect the micromechanical elements, thereby maintaining stable deflection control over time while preserving precise electrode control
Solution Approach 2:
The harmful electrical charge generated by electromagnetic radiation is extracted from the system by providing a dedicated conductive path through the conductive layer. This separates the charge collection function from the substrate, preventing charge accumulation that would otherwise cause deflection drift
2Productivity
If micromechanical elements are made small to increase array density, then more elements can be controlled per chip, but the electrostatic force becomes insufficient for reliable deflection
Solution Approach 1:
The electrode structure is extended vertically with a conductive layer positioned above the substrate. This three-dimensional arrangement increases the effective electrode surface area and electrostatic interaction volume without increasing the horizontal footprint, thereby maintaining sufficient deflection force for small micromechanical elements while preserving high array density
Solution Approach 2:
A composite electrode structure is formed by combining the substrate-based electrodes with an additional conductive layer positioned above the substrate. This composite structure increases the effective electrostatic force through enhanced charge distribution and field interaction, enabling reliable deflection of smaller micromechanical elements
3Ease of operation
If gaps are present between micromechanical elements to allow radiation passage, then substrate access is enabled, but electrical charging occurs on the substrate leading to force ratio disruption
Solution Approach 1:
The conductive layer serves as an intermediary that intercepts electrical charge generated by electromagnetic radiation passing through the gaps. By positioned between the radiation path and the substrate, it prevents charge accumulation on the substrate while maintaining the gap structure for radiation transmission
Solution Approach 2:
The electrical charge that would normally be harmful is converted into a beneficial effect by collecting it on the conductive layer. This collected charge can be managed or utilized, and more importantly, its collection prevents the harmful charge accumulation and force ratio disruption that would occur on the substrate
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 arrangement maintains long-term stability and precise control of micromechanical element deflection, reducing recalibration needs and avoiding charge-related disruptions, while enabling smaller and more efficient micro-optical element design.
Implementation Method 1
For the deflection of micromechanical elements, electrodes are arranged below the micromechanical elements, to which electrodes a predefinable electrical voltage can be applied for pivoting or translational deflection. The deflection takes place in accordance with the respective electrostatic force and the restoring force of the spring elements.
Implementation Method 2
The respective other electrode and the micro-optical element can be switched voltage-free and be at ground potential. However, there is also the possibility of supplying an electrical voltage to the micro-optical element by means of an electrical power supply, so that an electrostatic force can be used to pivot the micro-optical element in accordance with the respective difference in the electrical voltages between the electrode and the micro-optical element, which leads to the desired pivoting angle
Implementation Method 3
electrodes are arranged and designed in such a way that at least 50%, preferably at least 70%, of the electromagnetic radiation which can occur through gaps, taken into account the respective gap dimensions and the aperture, impinges on the surface of the electrodes
Data Source
Figure 1
AI summary
The invention relates to arrangements of micromechanical, preferably microoptical elements, which are each held by means of spring elements. In this case, they can be pivoted, or else deflected translationally, by the effect of electrostatic forces about a rotation axis. The object of the invention is to provide an arrangement with micromechanical elements which can be operated without drift over a long time period without any need for frequent recalibration. The arrangement according to the invention with micromechanical elements is in this case designed such that electrodes are likewise arranged underneath micromechanical elements, that is to say on the side which electromagnetic radiation cannot strike directly. In this case, in each case one electrode is arranged and designed such that it is associated with at least two micromechanical elements.