Optical Deflector Impact Attenuator Vibration Protection
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Solution Overview
Problem
Optical deflectors with integrated mirror and piezoelectric actuators on semiconductor substrates face issues with breakage and performance degradation due to external vibrations and impacts, as existing buffering mechanisms increase device size or compromise deflection and scanning performance.
Innovation Solution
An optical deflector design featuring a mirror, torsion bars, piezoelectric actuators, and an impact attenuator installed between the mirror and support, which absorbs vibrations and impacts without increasing device size, while maintaining deflection and scanning performance, using a semiconductor substrate and patterning processes for integral formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cushioning material is directly glued to a fixing frame, then the optical deflector is protected against external vibrations and impacts, but the area for gluing is limited and sufficient cushioning effects cannot be obtained
Solution Approach 1:
The cushioning mechanism is divided into two parts: a first cushioning material glued to the fixing frame and a second cushioning material between the mirror and the fixing frame. This segmentation allows each cushioning material to be optimally positioned and sized for its specific function, overcoming the limitation of limited gluing area on the fixing frame.
Solution Approach 2:
The cushioning protection is extended from a single plane (fixing frame bottom surface) to multiple dimensions by placing cushioning materials at different locations: on the fixing frame and between the mirror and fixing frame. This multi-dimensional approach increases the total effective cushioning area without increasing the device footprint.
2Strength
If the torsion bar is structured rigid to avoid destruction, then the strength increases, but the maximum deflection angle is reduced
Solution Approach 1:
Cushioning materials are installed in advance at strategic locations (between the mirror and fixing frame, and on the fixing frame) to provide protection before external vibrations or impacts occur. This allows the torsion bar to be designed for maximum deflection angle without compromising strength, as the cushioning materials will absorb extreme forces before they can cause destruction.
3Reliability
If the cross-sectional shape of the torsion bar is designed to buffer vibrations and impacts, then the reliability improves, but the number of manufacturing steps increases and yield is reduced
Solution Approach 1:
The vibration buffering function is extracted from the torsion bar structure itself and implemented through separate cushioning material components. This allows the torsion bar to be manufactured using simple, high-yield processes while the cushioning function is provided by separately manufactured materials that are easier to produce and assemble.
Solution Approach 2:
Instead of changing the geometric parameters of the torsion bar (cross-sectional shape) to achieve vibration buffering, the solution changes the material parameters by introducing cushioning materials with appropriate damping properties. This maintains simple torsion bar manufacturing while achieving the desired vibration buffering effect.
4Reliability
If a cushioning material is glued to the fixing frame, then protection against vibrations is provided, but stress is generated on the interface due to thermal expansion differences
Solution Approach 1:
The solution changes the material parameter by selecting a cushioning material with thermal expansion characteristics that better match those of the fixing frame and mirror. This reduces thermal mismatch stress at the interfaces while maintaining the vibration protection function.
Solution Approach 2:
The use of cushioning materials creates a composite structure that combines materials with different properties (structural components and damping materials). This composite approach allows optimization of both mechanical strength and thermal compatibility, reducing interface stress while maintaining vibration protection.
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 optical deflector effectively prevents breakage and maintains performance by absorbing external shocks through the impact attenuator, ensuring stable operation without size increase or performance loss, with improved durability and alignment precision.
Implementation Method 1
one or more piezoelectric cantilevers, the cantilever including a piezoelectric material formed on a supporting body to exhibit flexion deformity due to piezoelectricity when a driving voltage is applied thereto
Implementation Method 2
a characteristic impact attenuator being installed in the gap between the mirror and the support part
Data Source
AI summary
An optical deflector includes a mirror having a reflective plane; a torsion bar extending outwardly from a side of said mirror; a support surrounding said mirror; a piezoelectric cantilever including a supporting body and a piezoelectric body formed on the supporting body, one end of said piezoelectric cantilever being connected to said torsion bar, the other end of the piezoelectric cantilever being connected to said support, said piezoelectric cantilever, upon application of a driving voltage to the piezoelectric body, exhibiting a bending deformation due to piezoelectricity so as to rotate said torsion bar, thereby rotarily driving said mirror through said torsion bar; and an impact attenuator connected to said support, the impact attenuator being disposed in a gap between said mirror and said support.