Optical Deflector With Segmented Piezo Actuators
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Solution Overview
Problem
Existing optical deflector apparatuses, particularly those using piezoelectric actuators, face limitations in simultaneously achieving large rocking and offset deflection angles due to the shared use of actuators for both modes, leading to potential actuator damage and restricted deflection capabilities.
Innovation Solution
The optical deflector apparatus employs independent first and second piezoelectric actuators for rocking and offset operation modes, respectively, allowing for increased deflection angles by using meander-type and torsion-based piezoelectric actuators to generate combined drive voltages that do not exceed the actuator's threshold, thereby enhancing both rocking and offset deflecting amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the offset voltage is increased to increase the offset deflecting amount of the mirror, then the offset operation capability is improved, but the combined drive voltages exceed the threshold value and the piezoelectric actuators are damaged
Solution Approach 1:
The patent divides the single piezoelectric actuator into two separate actuators: a first piezoelectric actuator dedicated to rocking operation and a second piezoelectric actuator dedicated to offset operation. This segmentation allows each actuator to operate within its safe voltage threshold while achieving the desired deflection amounts independently, eliminating the risk of combined voltages damaging the actuators.
2Reliability
If the offset voltage is limited to protect the piezoelectric actuators, then the actuator safety is maintained, but the offset deflecting amount of the mirror cannot be increased
Solution Approach 1:
By segmenting the actuator system into two independent piezoelectric actuators, the patent enables the second actuator to provide additional offset deflection capability without constraining the first actuator's rocking operation. This allows the overall offset deflecting amount to exceed the limitations imposed by single-actuator voltage thresholds.
3Reliability
If the rocking drive voltages are decreased to accommodate higher offset voltage, then the actuator safety is maintained, but the rocking amount of the mirror cannot be increased
Solution Approach 1:
The patent assigns the first piezoelectric actuator exclusively to rocking operation, allowing it to operate at optimal drive voltages for maximum rocking amplitude. The second actuator handles offset operations independently, eliminating the need to reduce rocking drive voltages to accommodate offset requirements.
4Device complexity
If a single piezoelectric actuator is used for both rocking and offset operation modes, then the device complexity is reduced, but the simultaneous rocking and offset deflection capabilities are limited
Solution Approach 1:
The patent segments the actuator functions into two dedicated piezoelectric actuators, where the first actuator provides rocking deflection and the second actuator provides offset deflection. This segmentation enables simultaneous independent operation in both modes, achieving large deflection angles in both directions without the limitations of a shared actuator system.
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 configuration enables increased rocking and offset deflection angles without damaging the piezoelectric actuators, allowing for more flexible and effective optical axis adjustment in applications like adaptive front-lighting systems and laser projectors.
Implementation Method 1
piezoelectric actuators coupled between the mirror and the outer frame, serving as cantilevers for rocking the mirror
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
In an optical deflector apparatus including a mirror (1), an inner frame (2), an outer frame (3), an inner piezoelectric actuator (4a; 4b, 4b') adapted to flex the mirror (1) around an axis of the mirror (1), an outer piezoelectric actuator (6a-1, 6a-2, 6b-1, 6b-2; 7a, 7b, 7b') adapted to flex the mirror (1) around the axis of the mirror (1), and a driver (20) adapted to generate an offset drive voltage (VOFFSET1) VOFFSET2) and a rocking drive voltage (VX1), VX2; VX1', VX2'). The offset drive voltage (VOFFSET1, VOFFSET2) is applied to a first piezoelectric actuator selected from the inner piezoelectric actuator (4a; 4b, 4b') and the outer piezoelectric actuator (6a-1, 6a-2, 6b-1, 6b-2; 7a, 7b, 7b'). The rocking drive voltage (VX1) VX2; VX1', VX2') is applied to a second piezoelectric actuator different from the first piezoelectric actuator.