MEMS Optical Scanner with Bendable Beams for 2D Deflection
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Solution Overview
Problem
Conventional optical scanners face challenges in downsizing, cost reduction, and independent control of horizontal and vertical deflection due to complex mechanical structures and high costs, particularly in achieving accurate 2-dimensional scanning.
Innovation Solution
An optical scanner design featuring a mirror section supported by a movable frame with torsion bars and bendable beams, where actuators on the bendable beams cause bending oscillations to rotate the mirror section around two axes, allowing for independent horizontal and vertical deflection control without direct force application, thereby simplifying the structure and reducing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional mechanical structures (polygonal mirror or galvano-mirror) are used for optical scanning, then scanning function is achieved, but device size becomes large and cost increases
Solution Approach 1:
The patent replaces conventional mechanical scanning structures (polygonal mirrors driven by motors or galvanometers driven by electromagnetic actuators) with a micro-machined MEMS mirror structure. The mirror is suspended by elastic beams that can be actuated by electrostatic, electromagnetic, or piezoelectric forces, eliminating the need for large mechanical components and complex drive mechanisms, thereby reducing both size and cost.
Solution Approach 2:
The patent changes the operating parameters by using micro-scale dimensions and micro-machining techniques to create the mirror and support structures. This allows the system to achieve the same scanning function with dramatically reduced physical dimensions and lower material costs compared to conventional mechanical systems.
2Adaptability or versatility
If polygonal mirror and galvano-mirror are combined for 2-dimensional scanning, then scanning coverage is improved, but optical adjustment becomes very complicated
Solution Approach 1:
The patent segments the 2-dimensional scanning function into two independent rotational degrees of freedom of a single mirror, rather than requiring two separate mirrors. The mirror can rotate around a first axis and a second axis independently, achieving 2-D scanning coverage while eliminating the complex optical alignment required between multiple mirrors.
Solution Approach 2:
The patent merges the functions of multiple scanning mirrors into a single multi-axis rotatable mirror. This consolidation integrates the scanning functions that would otherwise require separate optical components and complex alignment procedures, simplifying the overall optical system while maintaining 2-dimensional scanning capability.
3Ease of operation
If distortion and bending oscillation are simultaneously conducted on the second double holding beam, then 2-axis rotation is achieved, but independent control of horizontal and vertical deflection becomes difficult
Solution Approach 1:
The patent segments the support structure into two functionally independent sets of elastic beams: one set for actuating rotation around the first axis and another set for actuating rotation around the second axis. This segmentation allows independent control of each rotational degree of freedom, avoiding the control coupling problems that arise when a single beam must perform multiple functions simultaneously.
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 design enables independent control of horizontal and vertical deflections, reduces deformation and deviation of reflected light, and allows for high-fidelity imaging while maintaining a compact and cost-effective device, facilitating easy adjustment of the scanning area and hand-vibration correction in scanning type projectors.
Implementation Method 1
a pair of actuators provided on the pair of bendable beams and to make the pair of bendable beams to cause a bending oscillation upon receipt of a predetermined driving signal
Data Source
AI summary
An optical scanner is provided with a mirror section; a movable frame positioned to surround the mirror section and to support the mirror section with a pair of torsion bars to hold the mirror section therebetween; a stationary frame to surround the movable frame and to support the movable frame with at least a pair of bendable beams, wherein one end of each of the pair of bendable beams is jointed to the stationary frame and the other end is jointed at a pair of joint sections to hold the movable frame therebetween and a first axis connecting the pair of torsion bars is arranged to be perpendicular to a second axis connecting the pair of joint sections; and a pair of actuators provided on the pair of bendable beams and to make the pair of bendable beams to cause a bending oscillation.