Optical Scanning Device Dual-Frequency Resonant Mirror
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Solution Overview
Problem
Existing omnidirectional LiDAR devices require high driving voltage for scanning donut-shaped incident surfaces due to slow response to amplitude modulation, which is inefficient.
Innovation Solution
An optical scanning device with a mirror portion that swings around two intersecting axes, driven by specific frequency and phase-modulated signals to achieve sinusoidal vibrations, reducing the need for high driving voltage by eliminating amplitude modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If spiral scan is used to scan donut-shaped incident surface, then scanning coverage is improved, but driving voltage increases due to slow response to amplitude modulation
Solution Approach 1:
The patent segments the scanning motion into two independent sinusoidal oscillations in orthogonal directions (X and Y axes), each driven by separate actuators. This allows the donut-shaped scanning path to be achieved through combination of simple harmonic motions rather than complex amplitude modulation, reducing the voltage required for each individual actuator.
Solution Approach 2:
The patent employs dynamic sinusoidal oscillation at resonant frequencies of the mirror structure. By operating at the natural resonant frequencies (fx1, fx2 for X-axis and fy1, fy2 for Y-axis), the system achieves efficient scanning motion with minimal driving voltage, as the mirror structure naturally amplifies the motion at these frequencies.
2Shape
If amplitude modulation is applied to achieve spiral scan, then scanning pattern is improved, but response time deteriorates due to slow modulation response
Solution Approach 1:
The patent segments the scanning control into independent sinusoidal oscillations in orthogonal directions, each with its own actuator and driving signal. This eliminates the need for time-varying amplitude modulation and allows each direction to be controlled independently at its resonant frequency, improving response time.
Solution Approach 2:
The patent utilizes mechanical vibration at resonant frequencies to achieve the scanning motion. The mirror structure is excited at its natural resonant frequencies (fx1, fx2 for X-axis and fy1, fy2 for Y-axis), causing it to vibrate sinusoidally with large amplitude using minimal driving voltage, thereby improving both response time and scanning efficiency.
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 allows for reduced driving voltage while maintaining effective scanning of donut-shaped surfaces, improving efficiency and reducing power consumption.
Implementation Method 1
a first actuator causing the mirror portion to swing around the first axis by applying a rotational torque around the first axis to the mirror portion
Implementation Method 2
a second actuator causing the mirror portion to swing around the second axis by applying a rotational torque around the second axis to the mirror portion
Implementation Method 3
a mirror device that has a mirror portion, which is swingable around a first axis and a second axis intersecting each other, having a reflecting surface reflecting incident light
Data Source
AI summary
A driving controller applies a first driving signal Vx(t) including two components of different frequencies f1 and f2 represented by the following equation (A) to a first actuator and a second driving signal Vy(t) including components of the frequencies f1 and f2 represented by the following equation (B) to a second actuator.VX(t)=Ax1sin(2πf1t)+Ax2sin(2πf2t+γ3). . . (A)Vy(t)=Ay1sin(2πf1t+γ1)+Ay2sin(2πf2t+γ3+γ22). . . (B)