MEMS Mirror Calibration via Lookup Table for Uniform Scanning
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Solution Overview
Problem
Electrostatic MEMS scanning mirrors face challenges in controlling swing angles due to non-linear relationships between DC voltages and swing angles, leading to non-uniform scanning intervals and image brightness issues in applications like image projection.
Innovation Solution
A driving calibration apparatus and method that sets multiple reference voltages to drive the mirror, detects corresponding projection positions, and establishes a lookup table to determine calibrated driving voltages for uniform image projection, ensuring consistent scanning intervals and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If DC voltages are used to control swing angles of the electrostatic MEMS scanning mirror, then the mirror can be driven to swing and reflect optical signals, but the swing angles are not linearly related to the DC voltages, causing non-uniform scanning intervals
Solution Approach 1:
The patent applies preliminary action by pre-establishing a lookup table that stores the non-linear correspondence between DC voltages and swing angles before actual operation. During operation, the system directly queries this pre-computed table to obtain the correct voltage for each desired angular position, eliminating the need for real-time non-linear calculations and ensuring uniform scanning intervals without complex control algorithms
Solution Approach 2:
The patent applies parameter changes by transforming the control approach from direct voltage control to lookup table-based voltage selection. The system changes the parameter representation from continuous non-linear voltage control to discrete pre-calibrated voltage values stored in the lookup table, each corresponding to a specific uniform angular position, thereby achieving linear scanning intervals through non-linear voltage parameters
2Productivity
If the electrostatic MEMS scanning mirror is used in image projection, then optical signals can be transmitted and projected, but non-uniform scanning intervals result in non-uniform brightness of projected images
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing in the lookup table the specific voltage values required to achieve uniform angular increments. This pre-computation accounts for the electrostatic mirror's non-linear characteristics, ensuring that when images are projected, each angular position receives the correct voltage to maintain uniform scanning speed and thus uniform image brightness across the entire projection area
Solution Approach 2:
The patent applies feedback by using the lookup table as a form of pre-established feedback mechanism. The system queries the lookup table to determine the appropriate voltage based on the desired angular position, effectively feedbacking the correct voltage value that compensates for non-linearities, thereby ensuring uniform brightness distribution in projected images without requiring real-time measurement and adjustment
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 calibrates driving voltages to prevent non-uniform scanning intervals and brightness issues, allowing for smooth and uniformly bright images by determining calibrated voltages based on actual electrical characteristics of the MEMS scanning mirror.
Implementation Method 1
the electrostatic MEMS scanning mirror controls swing angles by means of controlling DC voltages
Data Source
AI summary
The invention provides a driving calibration apparatus of an electrostatic MEMS scanning mirror and a driving calibration method thereof The driving calibration method includes the following steps. Different reference voltages are sequentially set to drive a plane mirror of the electrostatic MEMS scanning mirror to swing. Projection positions on a projected surface corresponding to the reference voltages that the laser beam projects to are determined. A driving lookup table is established according to the reference voltages and the corresponding projection positions. Calibrated driving voltages corresponding to ideal projection positions are determined according to the driving lookup table. The pane mirror is driven to swing according to the calibrated driving voltages.