U.S. patent application number 15/393268 was filed with the patent office on 2018-07-05 for mems apparatus having impact absorber.
This patent application is currently assigned to Industrial Technology Research Institute. The applicant listed for this patent is Industrial Technology Research Institute. Invention is credited to Yu-Wen Hsu, Chao-Ta Huang, Chin-Fu Kuo.
Application Number | 20180186624 15/393268 |
Document ID | / |
Family ID | 62684478 |
Filed Date | 2018-07-05 |
United States Patent
Application |
20180186624 |
Kind Code |
A1 |
Hsu; Yu-Wen ; et
al. |
July 5, 2018 |
MEMS APPARATUS HAVING IMPACT ABSORBER
Abstract
A MEMS apparatus includes a substrate, a cover disposed on the
substrate, a movable mass disposed on the substrate, and an impact
absorber disposed on the cover. The impact absorber includes a
restraint, a stationary stopper disposed on a lower surface of the
cover, a movable stopper, elastic elements connecting the restraint
and the movable stopper, a supporting element connecting the
restraint and the stationary stopper, and a space disposed between
the stationary stopper and the movable stopper. The impact absorber
is adapted to prevent the movable mass from impacting the cover. In
addition, the supporting element may be made of an electrical
insulation material to reduce electrostatic interaction between the
movable mass and the movable stopper.
Inventors: |
Hsu; Yu-Wen; (Tainan City,
TW) ; Kuo; Chin-Fu; (Tainan City, TW) ; Huang;
Chao-Ta; (Hsinchu City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Industrial Technology Research Institute |
Hsinchu |
|
TW |
|
|
Assignee: |
Industrial Technology Research
Institute
Hsinchu
TW
|
Family ID: |
62684478 |
Appl. No.: |
15/393268 |
Filed: |
December 29, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B81B 3/0086 20130101;
B81B 3/0072 20130101; B81B 3/0051 20130101 |
International
Class: |
B81B 3/00 20060101
B81B003/00 |
Claims
1. A MEMS apparatus, comprising: a substrate; a cover disposed on
the substrate; a movable mass disposed on the substrate; and an
impact absorber disposed on the cover, the impact absorber
comprising: a restraint; a stationary stopper disposed on a lower
surface of the cover; a movable stopper; an elastic element
connecting the restraint and the movable stopper; a supporting
element connected between the restraint and the stationary stopper;
and a space disposed between the stationary stopper and the movable
stopper.
2. The MEMS apparatus of claim 1, wherein the space is surrounded
by the supporting element.
3. The MEMS apparatus of claim 1, wherein the movable stopper is
configured to move toward the cover and an upper surface of the
movable stopper is adapted to enter the space when the movable mass
hits the movable stopper.
4. The MEMS apparatus of claim 1, wherein the movable stopper is
adapted to contact the stationary stopper.
5. The MEMS apparatus of claim 1, wherein a movable end of the
elastic element connects the movable stopper, a fixed end of the
elastic element connects the restraint, and a distance from the
movable end to the lower surface of the cover is less than a
distance from the fixed end to the lower surface of the cover when
the movable stopper moves toward the cover.
6. The MEMS apparatus of claim 1, wherein the movable stopper is
electrically insulated from the cover.
7. The MEMS apparatus of claim 6, wherein the supporting element is
made of an electrical insulation material.
8. The MEMS apparatus of claim 6, wherein the cover further
comprises a first semiconductor layer, a second semiconductor
layer, and an electrical insulation layer disposed between the
first semiconductor layer and the second semiconductor layer, the
movable stopper is electrically insulated from the first
semiconductor layer.
9. The MEMS apparatus of claim 8, wherein the movable stopper is
electrically connected to the second semiconductor layer, and the
movable stopper is adapted to be applied with a voltage through the
second semiconductor layer.
10. The MEMS apparatus of claim 6, wherein the cover further
comprises a first semiconductor layer, a second semiconductor
layer, and an electrical insulation layer disposed between the
first semiconductor layer and the second semiconductor layer, and
the supporting element is made of the same material as that of the
electrical insulation layer, and a thickness of the supporting
element is substantially equal to a thickness of the electrical
insulation layer.
11. The MEMS apparatus of claim 10, wherein the stationary stopper
is made of the same material as that of the first semiconductor
layer, the movable stopper is made of the same material as that of
the second semiconductor layer, and a distance from an upper
surface of the supporting element to an upper surface of the first
semiconductor layer is substantially equal to a distance from an
upper surface of the electrical insulation layer to an upper
surface of the first semiconductor layer.
12. The MEMS apparatus of claim 10, wherein a width of the elastic
element is less than a width of the restraint.
13. A MEMS apparatus, comprising: a substrate; a cover disposed on
the substrate, comprising a first semiconductor layer; a second
semiconductor layer; and an electrical insulation layer, wherein
the electrical insulation layer is disposed between the first
semiconductor layer and the second semiconductor layer; a movable
mass disposed on the substrate; an impact absorber disposed on the
cover, the impact absorber comprising: a restraint; a stationary
stopper disposed on a lower surface of the cover; a movable
stopper; an elastic element connecting the restraint and the
movable stopper; a supporting element connecting the restraint and
the stationary stopper; and a space disposed between the stationary
stopper and the movable stopper. wherein the supporting element is
made of the same material as that of the electrical insulation
layer, and a thickness of the supporting element is substantially
equal to a thickness of the electrical insulation layer.
14. The MEMS apparatus of claim 13, wherein the space is surrounded
by the supporting element.
15. The MEMS apparatus of claim 13, wherein the movable stopper is
configured to move toward the cover and an upper surface of the
movable stopper is adapted to enter the space when the movable mass
hits the movable stopper.
16. The MEMS apparatus of claim 13, wherein the movable stopper is
adapted to contact the stationary stopper.
17. The MEMS apparatus of claim 13, wherein a movable end of the
elastic element connects the movable stopper, a fixed end of the
elastic element connects the restraint, and a distance from the
movable end to the lower surface of the cover is less than a
distance from the fixed end to the lower surface of the cover when
the movable stopper moves toward the cover.
18. The MEMS apparatus of claim 13, wherein the stationary stopper
is made of the same material as that of the first semiconductor
layer, the movable stopper is made of the same material as that of
the second semiconductor layer, and a distance from an upper
surface of the supporting element to an upper surface of the first
semiconductor layer is substantially equal to a distance from an
upper surface of the electrical insulation layer to an upper
surface of the first semiconductor layer.
19. The MEMS apparatus of claim 13, wherein a width of the elastic
element is less than a width of the restraint.
Description
TECHNICAL FIELD
[0001] The present application relates to a MEMS
(Microelectromechanical Systems) apparatus, and more particularly,
to a MEMS apparatus having impact absorber.
BACKGROUND
[0002] At present, MEMS sensors have been widely applied to various
fields in modern life. For example, MEMS tire pressure detectors
have been applied to various vehicles, whereas MEMS sound
transducer, MEMS gyros or MEMS accelerometers have been applied to
various smart phones. There are also many other MEMS sensors
applied to smart electronic products required in the Internet of
things.
[0003] The MEMS sensor usually determines changes in physical
quantities (e.g., acceleration, angular velocity, geomagnetism,
etc.) through motion of a built-in movable element. When a motion
range is overly large, the movable element can suffer damages
caused by hitting surrounding structures (e.g., a cover). In the
prior art, a stationary stopper has been adopted to stop the
movable element from generating excessive movements. However, while
withstanding the movable element, the existing stopper can produce
enormous impact force and yet provide extremely short stop time so
the movable element or the surrounding structures can still be
damaged in the stopping process.
[0004] In addition, electrostatic interaction can be generated
between the existing stopper and the movable element. When the
movable element with electric charge is close to the stopper, the
stopper will generate an induced charge which interferes with a
voltage generated by the movable element during measurement thereby
affecting accuracy of the movable element during measurement of
physical quantities.
SUMMARY
[0005] The present application provides a MEMS apparatus having
impact absorber, which is capable of preventing a movable element
of the MEMS apparatus in motion from damages caused by hitting
surrounding structures so reliability of the MEMS apparatus can be
effectively ensured.
[0006] The present application also provides a MEMS apparatus
having impact absorber, which is capable of effectively preventing
operation of movable element from interference due to electrostatic
interaction to ensure accuracy during measurement.
[0007] A MEMS apparatus of the present application includes a
substrate, a cover, a movable mass, and an impact absorber. The
cover and the movable mass are disposed on the substrate. The
impact absorber is disposed on the cover. The impact absorber
includes a restraint, a stationary stopper, a movable stopper, an
elastic element, a supporting element, and a space. The stationary
stopper is disposed on a lower surface of the cover. The elastic
element connects the restraint and the movable stopper. The
supporting element connects the restraint and the stationary
stopper. The space is disposed between the stationary stopper and
the movable stopper.
[0008] In an embodiment of the present application, the space is
surrounded by the supporting element.
[0009] In an embodiment of the present application, the movable
stopper is configured to move toward the cover and an upper surface
of the movable stopper is adapted to enter the space when the
movable mass hits the movable stopper.
[0010] In an embodiment of the present application, the movable
stopper is adapted to contact the stationary stopper.
[0011] In an embodiment of the present application, a movable end
of the elastic element connects the movable stopper, and a fixed
end of the elastic element connects the restraint. A distance from
the movable end to the lower surface of the cover is less than a
distance from the fixed end to the lower surface of the cover when
the movable stopper moves toward the cover.
[0012] In an embodiment of the present application, the movable
stopper is electrically insulated from the cover.
[0013] In an embodiment of the present application, the supporting
element is made of an electrical insulation material.
[0014] In an embodiment of the present application, the cover
further includes a first semiconductor layer, a second
semiconductor layer, and an electrical insulation layer. The
electrical insulation layer is disposed between the first
semiconductor layer and the second semiconductor layer. The movable
stopper is electrically insulated from the first semiconductor
layer.
[0015] In an embodiment of the present application, the movable
stopper is electrically connected to the second semiconductor
layer, and the movable stopper is adapted to be applied with a
voltage through the second semiconductor layer.
[0016] In an embodiment of the present application, the cover
further includes a first semiconductor layer, a second
semiconductor layer, and an electrical insulation layer. The
electrical insulation layer is disposed between the first
semiconductor layer and the second semiconductor layer. The
supporting element is made of the same material as that of the
electrical insulation layer. A thickness of the supporting element
is substantially equal to a thickness of the electrical insulation
layer.
[0017] In an embodiment of the present application, the stationary
stopper is made of the same material as that of the first
semiconductor layer, the movable stopper is made of the same
material as that of the second semiconductor layer, and a distance
from an upper surface of the supporting element to an upper surface
of the first semiconductor layer is substantially equal to a
distance from an upper surface of the electrical insulation layer
to an upper surface of the first semiconductor layer.
[0018] In an embodiment of the present application, a width of the
elastic element is less than a width of the restraint.
[0019] A MEMS apparatus of the present application includes a
substrate, a cover, a movable mass, and an impact absorber. The
cover and the movable mass are disposed on the substrate. The
impact absorber is disposed on the cover. The cover includes a
first semiconductor layer, a second semiconductor layer, and an
electrical insulation layer. The electrical insulation layer is
disposed between the first semiconductor layer and the second
semiconductor layer. The impact absorber includes a restraint, a
stationary stopper, a movable stopper, an elastic element, a
supporting element, and a space. The stationary stopper is disposed
on a lower surface of the cover. The elastic element connects the
restraint and the movable stopper. The supporting element connects
the restraint and the stationary stopper. The space is disposed
between the stationary stopper and the movable stopper. The
supporting element is made of the same material as that of the
electrical insulation layer. A thickness of the supporting element
is substantially equal to a thickness of the electrical insulation
layer.
[0020] In an embodiment of the present application, the space is
surrounded by the supporting element.
[0021] In an embodiment of the present application, the movable
stopper is configured to move toward the cover and an upper surface
of the movable stopper is adapted to enter the space when the
movable mass hits the movable stopper.
[0022] In an embodiment of the present application, the movable
stopper is adapted to contact the stationary stopper.
[0023] In an embodiment of the present application, a movable end
of the elastic element connects the movable stopper, and a fixed
end of the elastic element connects the restraint. A distance from
the movable end to the lower surface of the cover is less than a
distance from the fixed end to the lower surface of the cover when
the movable stopper moves toward the cover.
[0024] In an embodiment of the present application, the stationary
stopper is made of the same material as that of the first
semiconductor layer, the movable stopper is made of the same
material as that of the second semiconductor layer, and a distance
from an upper surface of the supporting element to an upper surface
of the first semiconductor layer is substantially equal to a
distance from an upper surface of the electrical insulation layer
to an upper surface of the first semiconductor layer.
[0025] In an embodiment of the present application, a width of the
elastic element is less than a width of the restraint.
[0026] To make the above features and advantages of the present
application more comprehensible, several embodiments accompanied
with drawings are described in detail as follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The accompanying drawings are included to provide a further
understanding of the disclosure, and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments of the disclosure and, together with the description,
serve to explain the principles of the disclosure.
[0028] FIG. 1A is a schematic diagram of a MEMS apparatus in an
embodiment of the present application.
[0029] FIG. 1B is a schematic diagram of a MEMS apparatus in
another embodiment of the present application.
[0030] FIG. 2A and FIG. 2B are schematic diagrams of actions of the
impact absorber and the movable mass in FIG. 1A and FIG. 1B before
and after impact, respectively.
[0031] FIG. 3 illustrates a local structure of a MEMS apparatus in
an embodiment of the present application.
[0032] FIG. 4 is an exploded view of an impact absorber in an
embodiment of the present application.
[0033] FIG. 5 is an exploded view of an impact absorber in another
embodiment of the present application.
DETAILED DESCRIPTION
[0034] In the following detailed description, for purposes of
explanation, numerous specific details are set forth in order to
provide a thorough understanding of the disclosed embodiments. It
will be apparent, however, that one or more embodiments may be
practiced without these specific details. In other instances,
well-known structures and devices are schematically shown in order
to simplify the drawing.
[0035] FIG. 1A is a schematic diagram of a MEMS apparatus in an
embodiment of the present application. As shown in FIG. 1A, a MEMS
apparatus 10 of the present embodiment includes a substrate 100, a
cover 110, a movable mass 120, and an impact absorber 130. The
cover 110 is disposed on a surface of the substrate 100. The cover
110 and the substrate 100 constitute an accommodating space 140.
The movable mass 120 is disposed in the accommodating space 140
between the substrate 100 and the cover 110. In the present
embodiment, the movable mass 120 is, for example, a sensing mass
disposed in the MEMS apparatus for detecting physical quantities
(acceleration, angular velocity, geomagnetism, etc.) through
displacements of the sensing mass.
[0036] Further, the impact absorber 130 is disposed in the
accommodating space 140 on an inner side of the cover 110 and
configured to prevent the movable mass 120 in motion from impacting
the cover 110. The impact absorber 130 of the present embodiment
includes a stationary stopper 131, a supporting element 132, a
restraint 133, a movable stopper 134 and a plurality of elastic
elements 135. The stationary stopper 131 is disposed on a lower
surface of the cover 110. The supporting element 132 is disposed on
an outer edge of a lower surface of the stationary stopper 131. The
restraint 133 is disposed on a lower surface of the supporting
element 132 and surrounds the movable stopper 134. The elastic
element 135 connects the movable stopper 134 and the restraint 133
so the movable stopper 134 can move toward the stationary stopper
131. A space 136 is defined between the stationary stopper 131 and
the movable stopper 134 when the movable stopper 134 is not hit by
the movable mass 120. And space 136 serves as a buffer space when
the movable stopper 134 moves toward the stationary stopper
131.
[0037] FIG. 2A and FIG. 2B are schematic diagrams of actions of the
impact absorber 130 and the movable mass 120 in FIG. 1 before and
after impact. As shown in FIGS. 1, 2A and 2B, when an external
force (e.g., an acceleration force perpendicular to the surface of
the substrate) is applied on the MEMS apparatus 10, the movable
mass 120 can move toward the impact absorber 130 from the position
near the substrate 100 (FIG. 2A). When the movable mass 120 hits
the movable stopper 134, a stopper 1341 of the movable stopper 134
is in contact with the movable mass 120 so the movable stopper 134
then moves toward the cover 110 and enters the space 136 (FIG. 2B).
At this point, each of the elastic elements 135 is pulled by the
movable stopper 134 to generate elastic deformation for storing an
elastic potential energy. Conversely, once the external force is
removed, the movable mass 120 is no longer in contact with the
stopper 1341 of the movable stopper 134. The elastic potential
energy stored by the elastic element 135 is therefore released to
bring the movable stopper 134 back to the position shown in FIG.
2A.
[0038] The followings refer to FIG. 2A and FIG. 4 together.
Specifically, each of the elastic elements 135 in the present
embodiment has a movable end 1351 connecting the movable stopper
134 and a fixed end 1352 connecting the restraint 133. A width (We)
of the elastic element 135 is less than a width (Wr) of the
restraint 133. The elastic elements 135 of the present embodiment
are, for example, beams integrally formed with the movable stopper
134. For example, there are four beams connected to four corners of
the restraint 133 respectively. The number and shape of the elastic
elements 135 are not particularly limited in the present
application. The number and shape of the elastic elements 135 may
be adjusted according to design or other requirements.
[0039] In the present embodiment, the space 136 is surrounded by
the supporting element 132, and configured to provide the space
when the elastic element 135 deforms and when the movable stopper
134 moves, so a stop time (a time during which a speed of the
movable mass 120 becomes zero) of the movable stopper 120 can be
extended. In addition, kinetic energy of the movable mass 120 can
be absorbed by the deformation of the elastic element 135. Herein,
dimensions of the space 136 may be determined by taking into
consideration of various factors, such as dimensions of each
portion of the impact absorber 130 and magnitude of kinetic energy
generated by the movable mass 120.
[0040] As shown in FIG. 2A and FIG. 2B, when the movable mass 120
hits the movable stopper 134, each of the elastic elements 135
extends such that the movable end 1351 moves with the movable
stopper 134 and moves away from the respective fixed end 1352. At
this point, an upper surface of the movable stopper 134 enters the
space 136. When the movable stopper 134 reaches the stationary
stopper 131 and stops moving, the movable stopper 134 have a
maximum displacement. When the movable stopper 134 moves toward the
stationary stopper 131, a distance (Dm) from each movable end 1351
to the lower surface of the stationary stopper 131 is less than a
distance (Df) from the fixed end 1352 to the lower surface of the
stationary stopper 11.
[0041] A specific structure of the impact absorber 130 of the
present embodiment will be described below with provided examples.
FIG. 3 illustrates a local structure of a MEMS apparatus in an
embodiment of the present application. FIG. 4 is an exploded view
of an impact absorber in an embodiment of the present application.
Referring to FIGS. 1, 3 and 4 together, the cover 110 and the
impact absorber 130 may be manufactured by a SOI (Silicon On
Insulator) substrate at the same time. Specifically, the SOI
substrate includes a handle layer, a device layer, and an
insulation layer disposed between the handle layer and the device
layer. The handle layer and the device layer are made of silicon,
and the insulation layer is an electrical insulation layer such as
silicon dioxide (SiO2). In the present embodiment, the device layer
is used to manufacture the restraint 133, the movable stopper 134,
the elastic elements 135 in the impact absorber 130 and a second
semiconductor layer 112 of the cover 110. The insulation layer is
used to manufacture the supporting element 132 in the impact
absorber 130 and an electrical insulation layer 114 of the cover
110. The handle layer is used to manufacture the stationary stopper
131 in the impact absorber 130 and a first semiconductor layer 116
of the cover 110.
[0042] As described above, the cover 110 formed in the present
embodiment includes the first semiconductor layer 116, the
electrical insulation layer 114, and the second semiconductor layer
112. The first semiconductor layer 116 serves as a top portion of
the cover 110 and covers the accommodating space 140. Because the
electrical insulation layer 114 is disposed between the first
semiconductor layer 116 and the second semiconductor layer 112 and
the supporting element 132 connecting the movable stopper 134 is
also made of an electrical insulation material, the movable stopper
134 is electrically insulated from the cover 110. More
specifically, due to separation by the electrical insulation layer
114 and the supporting element 132, the movable stopper 134 is
electrically insulated from the first semiconductor layer 116 and
the second semiconductor layer 112 of the cover 110. Accordingly,
the movable stopper 134 can be prevented from generating the
induced charge due to the external electromagnetic interference to
thereby reduce electrostatic interaction between the movable
stopper 134 and the movable mass 120. Therefore, accuracy of the
MEMS apparatus 10 during measurement can be improved by making the
movable stopper 134 electrically insulated from the cover 110.
[0043] On the other hand, the supporting element 132 of the present
embodiment is, for example, a frame structure configured to
surround the space 136. Because the electrical insulation layer 114
in the cover 110 and the supporting element 132 in the impact
absorber 130 are manufactured using the same insulation layer in
the SOI substrate, the supporting element 132 and the electrical
insulation layer 114 are made of the same material. In other words,
in the present embodiment, the supporting element 132 is made of
the electrical insulation material. In addition, with a structural
design in which a thickness Ts of the supporting element 132 is
substantially equal to a thickness Tc of the electrical insulation
layer 114, the supporting element 132 and the electrical insulation
layer 114 can be manufactured at the same time using the same wet
etching process, such as a HF wet etching process. In this way, the
effect of reducing processing time and lowering processing costs
can then be achieved. Since the supporting element 132 is the
electrical insulation material, the stationary stopper 131 and the
restraint 133 are electrically insulated from each other. In
addition, in order to simultaneously manufacture the supporting
element 132 and the space 136 by etching the insulation layer of
the SOI substrate using the same wet etching process, a width (We)
of the elastic element 135 can be made to be less than a width (Wr)
of the restraint 133, as shown in FIG. 4.
[0044] In the present embodiment, the first semiconductor layer 116
and the stationary stopper 131 are manufactured using a dry etching
(e.g., Deep Reaction Ion Etching; Deep RIE) process adopted by the
same handle layer of the same SOI substrate. Therefore, the
stationary stopper 131 is made of the same silicon material as that
of the first semiconductor layer 116. With a restraining condition
in which a distance (Ds) from an upper surface of the supporting
element 132 to an upper surface of the first semiconductor layer
116 is substantially equal to a distance (Dc) from an upper surface
of the electrical insulation layer 114 to an upper surface of the
first semiconductor layer 116, the stationary stopper 131 and the
first semiconductor layer 116 can be manufactured at the same time
using the same dry etching process. In this way, the effect of
reducing processing time and lowering processing costs can then be
achieved.
[0045] FIG. 1B is a schematic diagram of a MEMS apparatus in an
embodiment of the present application. As shown in FIG. 1B, a
structure of the present embodiment is approximately identical to
that of the embodiment in FIG. 1A. The difference is that, the
impact absorber 130 in FIG. 1B has a first electrical path 137, a
second electrical path 138 and an intermediate layer 139. Among
them, the first electrical path 137 is disposed between the
stationary stopper 131 and the first semiconductor layer 116. The
first electrical path 137 is, as similar to the first semiconductor
layer 116 and the stationary stopper 131, manufactured by the same
handle layer of the SOI substrate. Thus, the first electrical path
137 is, for example, made of the silicon material.
[0046] In the present embodiment, the second electrical path 138 is
disposed between the restraint 133 and the second semiconductor
layer 112. The second electrical path 138 is, as similar to the
second semiconductor layer 112 and the movable stopper 134,
manufactured by the same device layer of the SOI substrate. Thus,
the second electrical path 138 is, for example, made of the silicon
material.
[0047] In the present embodiment, the intermediate layer 139
connects each of the supporting element 132 and the electrical
insulation layer 114. The intermediate layer 139 is disposed
between the first electrical path 137 and the second electrical
path 138. Because the intermediate layer 139 is, as similar to the
supporting element 132 and the electrical insulation layer 114,
manufactured by the same insulation layer of the SOI substrate, the
intermediate layer 139 is, for example, made of the electrical
insulation material. Hence, the first electrical path 137 is
electrically insulated from the second electrical path 138.
[0048] Referring to FIG. 1B, more specifically, the movable stopper
134 is electrically connected to the second semiconductor layer 112
through the elastic elements 135, the restraint 133 and the second
electrical path 138. The movable stopper 134 can be applied with a
voltage (identical to a voltage of the movable mass 120) through
the second semiconductor layer 112, the second electrical path 138,
the restraint 133 and the elastic element 135. In this way, because
there is no voltage difference between the movable stopper 134 and
the movable mass 120, the induced charge may be prevented from
being generated to thereby reduce electrostatic interaction between
the movable stopper 134 and the movable mass 120.
[0049] In addition, as shown in FIGS. 1 to 4, in the foregoing
embodiments, to further ensure that the movable stopper 134 can
impact properly with the movable mass 120, the stopper 1341 of the
movable stopper 134 can be made protruding outside the restraint
133 and facing the movable mass 120. In this way, when moving
toward the movable stopper 134, the movable mass 120 will hit the
stopper 1341 first instead of the restraint 133. Accordingly, the
restraint 133 can be prevented from damages caused by overly large
impact force.
[0050] FIG. 5 is an exploded view of an impact absorber in another
embodiment of the present application. As shown in FIG. 5, an
impact absorber 130A of the present embodiment has a structure
approximately identical to that of the impact absorber 130 in FIG.
4. The difference is that, the stationary stopper 131 of the impact
absorber 130 in FIG. 4A is a solid structure, whereas a stationary
stopper 131A of the present embodiment has a groove 1311A and a
plurality of elastic elements 135A. The groove 1311A penetrates the
stationary stopper 131A so multiple pillars are formed to serve as
the elastic elements 135A. In the present embodiment, a weight of
the stationary stopper 131A can be reduced while maintaining the
same structural strength of the stationary stopper 131 with the
groove 1311A. When the movable stopper 134 hits the stationary
stopper 131A due to overly large impact force, the elastic elements
135A can provide the similar impact bearing capability of the
stationary stopper 131 of the solid structure.
[0051] In summary, the present application provides a MEMS
apparatus having impact absorber, in which the impact absorber is
disposed between the cover and the movable mass. As a result, the
impact absorber can absorb impact energy of the movable mass to
prevent the movable mass from damages and failures caused by
hitting the cover or other internal structures. In addition, the
impact absorber can reduce electrostatic interaction between the
movable mass and the movable stopper by the supporting element made
of the electrical insulation material to thereby improve accuracy
during measurement.
[0052] It will be apparent to those skilled in the art that various
modifications and variations can be made to the disclosed
embodiments. It is intended that the specification and examples be
considered as exemplary only, with a true scope of the disclosure
being indicated by the following claims and their equivalents.
* * * * *