CN106249403A - The method strengthening MEMS micromirror resistance ability - Google Patents
The method strengthening MEMS micromirror resistance ability Download PDFInfo
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- CN106249403A CN106249403A CN201610813342.4A CN201610813342A CN106249403A CN 106249403 A CN106249403 A CN 106249403A CN 201610813342 A CN201610813342 A CN 201610813342A CN 106249403 A CN106249403 A CN 106249403A
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- China
- Prior art keywords
- micro mirror
- mems micromirror
- resistance ability
- dynamic deformation
- mems
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
- G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
- G02B26/0816—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements
- G02B26/0833—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD
Abstract
The present invention relates to a kind of method strengthening MEMS micromirror resistance ability, belong to mems device and manufacture field.This method uses the method increasing circular ring structure at micro mirror back to reduce dynamic deformation when micro mirror vibrates, and ensures the micro mirror normal deflection to light beam.Have the advantages that cost is lower, system is simpler, volume is more exquisite, operability is higher.By three kinds of different back structures of comparison, cirque structure is while reducing dynamic deformation, it is possible to reduce processing step, saves process costs.
Description
Technical field
The present invention relates to a kind of method strengthening MEMS micromirror resistance ability, belong to mems device and manufacture field.
Background technology
MEMS:MEMS is the english abbreviation of MEMS (Micro-Electro-Mechanical Systems).It
Being a kind of industrial technology microelectric technique and mechanical engineering being fused together, its opereating specification is in micrometer range.
MEMS mainly includes several parts such as micro mechanism, microsensor, micro actuator and corresponding process circuit, and it is to merge
Multiple Micrometer-Nanometer Processing Technology, and the high-tech forward position grown up on the basis of applying the newest fruits of modern information technologies learns
Section.
MEMS micromirror belongs to microoptical electromechanical device, is a kind of luminous reflectance type device, has been applied to micro projection, optic communication
And many many fields such as laser radar.The range of application of MEMS micromirror is increasingly wider at present, is generally operational in quasistatic or resonance
State, as vibrated under resonance condition, speed is exceedingly fast, and frequency of vibration is up to 20kHz ~ 30kHz.Under such kinestate micro-
Mirror occurrence dynamics deformation can make surface smoothness be deteriorated, thus has a strong impact on the deflection of the light beam incided on minute surface, finally
Affect the working effect of micro mirror.And its surface smoothness multipair has higher requirements in the use occasion of current MEMS micromirror, as will
When micro mirror is applied in laser scanning system, micro mirror surfaces flatness will affect the angle of divergence of reflection laser thus affect projection
The resolution of imaging.
Alleviation currently, with respect to the deformation on MEMS micromirror surface improves mode, mainly has: (1) is by corresponding optical system
System compensates the aberration caused by minute surface out-of-flatness；This technical costs is high, needs the optical element increasing auxiliary to build
Optical compensating system realizes；Add the complexity of system, improve the difficulty at aspects such as alignment, debugging.(2) directly increase
Add micro mirror surfaces thickness；The method improves the stability of micro mirror surfaces to a certain extent so that micro mirror is in vibration at high speed situation
Under dynamic deformation alleviated.But, along with the increase of torsional mirror face thickness, weight and the rotary inertia of MEMS micromirror also must
So can increase therewith, in the case of ensureing certain rotational frequency, the coefficient of torsional rigidity of scanning micro-mirror torsion beam must be increased,
So certainly will increase micro mirror and rotate the driving moment required for equal angular and the stress distribution on torsional axis, increase driving
Difficulty, reduces the impact resistance of micro mirror.Meanwhile, the method directly increasing micro mirror surfaces thickness, in the course of processing, can be many
One step photoetching and etching, thus add the complexity of cost and operation.
Summary of the invention
Deformation when vibrating for micro mirror, it is an object of the invention to provide a kind of method strengthening MEMS micromirror resistance ability
Slow down micro mirror deformation on its surface when vibration at high speed, thus obtain of a relatively high micro mirror surfaces flatness, optimize MEMS and exist
The service behaviour of the aspects such as scanning, projection.
For reaching above-mentioned purpose, insight of the invention is that
(1) theory analysis
Micro mirror is driven moment loading when torsional axis high-speed rotation, and its surface can occurrence dynamics deformation.According to
The flat-plate theory of S.Timoshenko, by the displacement formula (formula 1) of silicon materials micro mirror:
(1)
Derive its maximum dynamic deformation formula (formula 2):
(2)
The maximum dynamic deformation formula derived, material is silicon, and micromirror duty is at resonant condition, dynamic deformationδValue and torsion
Size (the length of axleL f, width 2a, thickness 2b), the size (thickness of micro mirrortAnd radiusL) and windup-degreeθ 0 Relevant, public
Formula (2) shows to increase minute surface thicknesstCan greatly reduce dynamic deformation, the present invention will be subtracted by the back structures increasing micro mirror
The dynamic deformation of little micro mirror.
In the actual processing of micro mirror, due to SOI(Silicon On Insulator, the silicon in dielectric substrate) substrate
Bottom silicon thickness more much bigger than top layer silicon thickness (>=5 times), typically with top layer silicon make minute surface and torsional axis, i.e. minute surface thickness with
The thickness of torsional axis is the same (also referred to as without back structures, referred to as structure one), and comes by increasing the thickness of minute surface
Reduce dynamic deformation, for the convenience of technique, the bottom silicon under minute surface can only be retained, if the end under minute surface is fully retained
Layer silicon (method directly increasing micro mirror surfaces thickness that i.e. presently, there are, referred to as structure two), this can greatly reduce micro mirror
Dynamic deformation, but the quality of this part bottom silicon is too big, can exceed the intensity of torsional axis so that torsional axis is easily broken, and
The resonant frequency of micro mirror can be greatly reduced, increase micro mirror thickness that therefore can not be simple, mechanical.Therefore, in order to ensure torsion
On the premise of shaft strength, the present invention proposes the bottom silicon of micro mirror bottom to make the back structures (knot of the present invention of annular
Structure three), This reduces both the quality of micro mirror, it is ensured that the intensity of torsional axis, the dynamic deformation of micro mirror surfaces can be slowed down again.
(2) software simulation
According to above design, utilize COMSOL software that three kinds of structures are simulated simulation comparison.Keeping cornerθIdentical
In the case of, the maximum dynamic deformation of micro mirror is respectively 486nm, 243.3nm, 245.2nm, it is apparent that annulus back structures
Increase can reduce dynamic deformation amount；And structure three is close with the dynamic deformation of structure two, but structure two can increase
The difficulty of processing, for the consideration of easy making process, the present invention uses the circular ring structure of structure three to reduce the dynamic of MEMS micromirror
State deforms.
According to above inventive concept, the present invention uses following technical proposals:
A kind of method strengthening MEMS micromirror resistance ability: increase circular ring structure at MEMS micromirror back and improve and alleviate MEMS
Micro mirror dynamic deformation under high-speed rotation.
The method of described enhancing MEMS micromirror resistance ability, micro mirror generally circular in shape；
The method of described enhancing MEMS micromirror resistance ability, back structures be shaped as annulus；
The method of described enhancing MEMS micromirror resistance ability, the external diameter of annulus is more than zero less than the diameter of micro mirror, internal diameter.
The method of the present invention and the side of the current aberration compensated by respective optical system caused by minute surface out-of-flatness
Method is compared, and has and will be apparent below prominent substantive distinguishing features and notable technological progress: the range of application of a. present invention is more
Extensively, it is applicable not only to the situation of micro mirror static deformation, is also the situation for any micro mirror dynamic deformation；B. due to this
Invention has only to increase by a step in MEMS micromirror manufacturing process and simply etches and can realize, without the phase increasing auxiliary
Optical system is answered to compensate, so its cost is lower, system is simpler, volume is more exquisite, operability is higher.
The present invention can improve micro mirror surfaces in the case of ensureing that other stable performances of MEMS micromirror are good simultaneously
Flatness.The advantage comparing its maximum with the method for the current existing direct thickness of increase micro mirror own can ensure that micro mirror exactly
The stable performances such as certain rotational frequency, deflection angle, driving moment and torsional axis stress are good.Because the design of the present invention,
Not only by increase micro mirror back structures thus increase fraction quality, improve micro mirror surfaces stability, increase micro mirror inclined
Gyration；Gone out the back structures of difformity and size simultaneously by design of Simulation, thus promote micro mirror surfaces flatness, reduction
Damping in micro mirror rotation process.
Accompanying drawing explanation
Fig. 1 is deformation schematic diagram during micro mirror vibration.
Fig. 2 is the micro mirror graphics (structure one) without back structures.
Fig. 3 is the micro mirror graphics (structure two) having back column structure.
Fig. 4 is the micro mirror graphics (structure three) having back circular ring structure of the present invention.
Fig. 5 is the dynamic deformation simulation drawing of structure one.
Fig. 6 is the dynamic deformation simulation drawing of structure two.
Fig. 7 is the dynamic deformation simulation drawing of the structure three of the present invention.
Detailed description of the invention
It is as follows that the preferred embodiments of the present invention combine detailed description:
Embodiment one
See Fig. 4, the method for this enhancing MEMS micromirror resistance ability, it is characterised in that: annulus knot is increased at MEMS micromirror back
Structure improves and alleviates MEMS micromirror dynamic deformation under high-speed rotation.
Embodiment two
The present embodiment is essentially identical with embodiment one, and special feature is as follows:
The method of described enhancing MEMS micromirror resistance ability, micro mirror generally circular in shape；
The method of described enhancing MEMS micromirror resistance ability, back structures be shaped as annulus；
The method of described enhancing MEMS micromirror resistance ability, the external diameter of annulus is more than zero less than the diameter of micro mirror, internal diameter.
Embodiment three
The present embodiment is essentially identical with embodiment two, and special feature is as follows:
Micro-mirror structure parameter is set,L=0.5mm,L f=0.5mm,a=30um,b=15um, the corner keeping micro mirror is identical, logical
Cross structure one shown in comparison diagram 2 (t=30um) with structure two shown in Fig. 3 (t=23um) dynamic deformation, maximum dynamic deformation
Value is respectively 486nm, 243.3nm, illustrates that back cylinder can significantly reduce the dynamic deformation of micro mirror.By arranging micro mirror back circle
The internal diameter of ring and external diameter are respectively 0.72mm, 0.9mm, thicknesstStructure three shown in Fig. 4 of=100um, i.e. the present embodiment, now
The maximum dynamic deformation of micro mirror is 245.2nm, and structure two is close with the dynamic deformation of structure three, but the structure of the present embodiment three
Being prone to processing, can save step photoetching and an etching, cost-effective, structure three is the splendid scheme reducing dynamic deformation.Fig. 5,
Fig. 6, Fig. 7 are shown respectively the dynamic deformation simulation drawing of the structure three of structure one, structure two and the present embodiment.
Claims (4)
1. the method strengthening MEMS micromirror resistance ability, it is characterised in that:
MEMS micromirror back increase circular ring structure improve and alleviate MEMS micromirror in high-speed rotation under dynamic deformation.
The method of enhancing MEMS micromirror resistance ability the most according to claim 1, it is characterised in that being shaped as of micro mirror is round
Shape.
The method of enhancing MEMS micromirror resistance ability the most according to claim 1, it is characterised in that the shape of back structures
For annulus.
The method of enhancing MEMS micromirror resistance ability the most according to claim 1, it is characterised in that the external diameter of annulus does not surpasses
Crossing the diameter of micro mirror, internal diameter is more than zero.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201610813342.4A CN106249403A (en) | 2016-09-10 | 2016-09-10 | The method strengthening MEMS micromirror resistance ability |
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| CN201610813342.4A CN106249403A (en) | 2016-09-10 | 2016-09-10 | The method strengthening MEMS micromirror resistance ability |
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| CN201610813342.4A Pending CN106249403A (en) | 2016-09-10 | 2016-09-10 | The method strengthening MEMS micromirror resistance ability |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107247330A (en) * | 2017-08-11 | 2017-10-13 | 重庆大学 | The integrated MOEMS raster micro mirror of piezoelectric type |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101950079A (en) * | 2010-05-26 | 2011-01-19 | 香港应用科技研究院有限公司 | Biaxial scanning mirror with tunable resonant frequency |
| CN202880858U (en) * | 2012-05-28 | 2013-04-17 | 凝辉(天津)科技有限责任公司 | Double-micromirror rotary scanning device |
| CN103569936A (en) * | 2012-07-30 | 2014-02-12 | 先进微系统科技股份有限公司 | Vibration structure of micro actuator |
-
2016
- 2016-09-10 CN CN201610813342.4A patent/CN106249403A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101950079A (en) * | 2010-05-26 | 2011-01-19 | 香港应用科技研究院有限公司 | Biaxial scanning mirror with tunable resonant frequency |
| CN202880858U (en) * | 2012-05-28 | 2013-04-17 | 凝辉(天津)科技有限责任公司 | Double-micromirror rotary scanning device |
| CN103569936A (en) * | 2012-07-30 | 2014-02-12 | 先进微系统科技股份有限公司 | Vibration structure of micro actuator |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107247330A (en) * | 2017-08-11 | 2017-10-13 | 重庆大学 | The integrated MOEMS raster micro mirror of piezoelectric type |
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Application publication date: 20161221 |