Micromirror Precession Scanning With Split Resonance Frequencies
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing micromirror devices experience crosstalk and reduced deflection angles when resonance frequencies are matched, leading to increased power consumption and drive circuit size, which hinders efficient precession scanning.
Innovation Solution
A micromirror device with a first and second actuator driven by piezoelectric elements, where the resonance frequencies satisfy f2 < f1, and driving frequencies satisfy fd ≤ f1, with a phase difference of 90°, to maintain low power consumption while improving deflection angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the first resonance frequency is matched with the second resonance frequency to improve responsiveness, then the deflection angle increases, but crosstalk between actuators increases
Solution Approach 1:
The patent changes the resonance frequency parameter relationship from f1=f2 to f2<f1, specifically setting the first resonance frequency higher than the second resonance frequency. This parameter change resolves the contradiction by avoiding the crosstalk that occurs when frequencies are matched, while still achieving good responsiveness through optimized driving frequencies fd≤f1
2Force
If driving amplitude voltage is increased to improve deflection angle, then the deflection angle increases, but power consumption increases
Solution Approach 1:
The patent utilizes resonance vibration by setting driving frequencies fd≤f1 to excite the micromirror device at its natural frequency. This allows achieving large deflection angles through resonant amplification rather than simply increasing driving voltage, thereby resolving the contradiction between deflection angle and power consumption
Solution Approach 2:
The patent changes the operating frequency parameter to match or be slightly below the first resonance frequency, enabling the system to achieve maximum deflection angle at lower power consumption through resonant effects rather than brute-force voltage increases
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 enhances deflection angles and reduces power consumption by minimizing crosstalk, allowing for precise precession scanning with low amplitude voltages.
Implementation Method 1
a first actuator that allows the mirror portion to swing around a first axis located in a plane including the reflecting surface in a case in which the mirror portion is stationary, and a second actuator that allows the mirror portion to swing around a second axis orthogonal to the first axis in the plane
Implementation Method 2
The micromirror device resonates at a natural vibration frequency determined by a mass, structure, and spring constant. By driving the micromirror device at the resonance frequency, a larger scan angle is obtained.
Data Source
AI summary
An optical scanning device includes: a micromirror device, a first actuator that allows the mirror portion to swing around a first axis, and a second actuator that allows the mirror portion to swing around a second axis orthogonal to the first axis; and a processor that causes the mirror portion to perform precession by providing a first driving signal and a second driving signal each having the same driving frequency to the first actuator and the second actuator, respectively. In the micromirror device, a relationship of f2<f1 is satisfied in a case in which a resonance frequency around the first axis is denoted by f1 and a resonance frequency around the second axis is denoted by f2, and a relationship of fd≤f1 is satisfied in a case in which the driving frequency is denoted by fd.