Measuring and testing – Vibration – Sensing apparatus
Reexamination Certificate
2000-01-10
2001-10-30
Williams, Hezron (Department: 2856)
Measuring and testing
Vibration
Sensing apparatus
C073S504120, C073S504080, C310S309000, C360S294200
Reexamination Certificate
active
06308573
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a 3-dimensional comb structure using an electrostatic force, and an inertia detection sensor and an actuator which uses the 3-dimensional comb structure.
2. Description of the Related Art
A 3-dimensional comb structure using an electrostatic force protrudes perpendicularly with respect to a flat plane surface, and has a structure such that an electrostatic force, which is generated between a pair of interlocked combs by applying a voltage thereto, is constant with respect to the relative motion between the combs.
In many cases, electrostatic actuators are used to move micro structures. An electrostatic comb drive (U.S. Pat. No. 5,025,346) is well known as an electrostatic actuator. The basic principle of the electrostatic comb drive will now be described with reference to FIG.
1
.
A pair of combs
1
and
2
mesh with each other with a gap s between fingers thereof. When a power supply
3
is connected to each of the combs
1
and
2
via conductive wires
4
and
5
, respectively, a horizontal electrostatic force (F
s
)
6
acting upon a finger of the comb
2
is expressed by the following Equation 1:
F
S
=
ϵ
0
t
s
V
2
(
1
)
wherein &egr;
0
, t, s and V denote the permittivity of free space, the thickness of a finger in a direction perpendicular to the surface, the interval between a finger of the comb
1
and an adjacent finger of the comb
2
, and a voltage
3
applied to a bridge between fingers, respectively. The electrostatic comb drive can be manufactured by a CMOS process such as a process for manufacturing a semiconductor RAM, and has a constant force with respect to the motion of a comb, as shown in Equation 1.
FIG. 2
disclosed in U.S. Pat. No. 5,025,346 can be taken as an example of an actuator using the principle of
FIG. 1
, which is the principle of an existing electrostatic comb drive. This electrostatic actuator
20
includes a mass body
22
having a plurality of movable comb fingers
27
, at least one elastic member
23
connected to the mass body
22
, and a plurality of fixed combs
25
which are meshed with the movable comb fingers
27
, facing the movable comb fingers
27
. Here, the plurality of movable comb fingers
27
are supported by a substrate
21
via supporters
24
, and the fixed comb fingers
25
are supported by the substrate
21
via fixed comb supporters
26
. When a voltage is applied to the fixed comb fingers
25
and the movable comb fingers
27
via an appropriate means (not shown), the mass body
22
is moved linearly in a horizontal direction with respect to the substrate
21
by the electrostatic force generated by Equation 1. The electrostatic force generated in this structure is constant with respect to the distance of motion, as shown in Equation 1. However, according to this structure, the movable comb fingers
27
and the fixed comb fingers
25
are parallel to the substrate
21
. Also, since the movable comb fingers
27
and the fixed comb fingers
25
are installed on both ends of the flat mass body which is parallel to the substrate
21
, the number of combs can increase in proportion to the length of each end of the mass body. Thus, an electrostatic force is small due to the limit in the number of combs. Furthermore, the mass body must move largely to be used in acceleration sensors or gyro sensors. However, in this conventional comb structure, a small amount of electrostatic force makes it difficult to directly drive the mass body, so that the mass body can only be driven at the resonance point.
SUMMARY OF THE INVENTION
To solve the above problems, an objective of the present invention is to provide a 3-dimensional comb structure which is strong enough to drive a large-sized structure and having fingers arranged perpendicularly over a flat plane to make it easy to control the position of the structure, and an actuator and an inertia detection sensor both using the 3-dimensional comb structure.
To achieve the above objective of the invention, there is provided a 3-dimensional comb structure including: a substrate; a suspension structure separated a predetermined height from the substrate, maintaining the predetermined height therefrom, such that the suspension structure can vibrate over the substrate to detect an inertial movement; at least one elastic member connected to the suspension structure, for supporting the suspension structure so that the suspension structure makes an inertial movement; a movable comb having at least one comb finger, the movable comb protruding from the suspension structure; and a fixed comb having at least one comb finger, the fixed comb fingers protruding from the substrate opposite to and in mesh with the movable comb fingers.
In the present invention, preferably, an electrostatic force is generated perpendicular to the direction of protrusion of the movable comb fingers from the suspension structure, when a voltage is applied to the movable comb and the fixed comb, so that the 3-dimensional comb structure is excited parallel to the substrate. It is preferable that the movable comb is meshed with the fixed comb having a predetermined gap between a finger of the movable comb and a finger of the fixed comb.
It is also preferable that the movable comb and the fixed comb face each other, and are arranged on the suspension structure and the substrate, respectively, in a circular symmetrical manner, such that the suspension structure is horizontal to the substrate and rotates around the center of the circular symmetry.
To achieve the above objective of the invention, there is provided an inertia detection sensor adopting a 3-dimensional comb structure including: a substrate; a suspension structure separated a predetermined height from the substrate, maintaining the predetermined height therefrom, such that the suspension structure can vibrate over the substrate to detect an inertial movement; at least one elastic member connected to the suspension structure, for supporting the suspension structure so that the suspension structure makes an inertial movement; a movable comb having at least one comb finger, the movable comb protruding from the suspension structure; a fixed comb having at least one comb finger, the fixed comb fingers protruding from the substrate opposite to and in mesh with the movable comb fingers; and a sensing unit for detecting an acceleration by sensing a capacity change between the movable comb and the fixed comb.
Preferably, an electrostatic force is generated perpendicular to the direction of protrusion of the movable comb fingers from the suspension structure, when a voltage is applied to the movable comb and the fixed comb, so that the 3-dimensional comb structure is excited parallel to the substrate. It is preferable that the movable comb is meshed with the fixed comb having a predetermined gap between a finger of the movable comb and a finger of the fixed comb.
It is also preferable that the movable comb and the fixed comb face each other, and are arranged on the suspension structure and the substrate, respectively, in a circular symmetrical manner, such that the suspension structure is horizontal to the substrate and rotates around the center of the circular symmetry.
To achieve the above objective of the invention, there is provided an actuator adopting a 3-dimensional comb structure comprising: a substrate; a suspension structure separated a predetermined height from the substrate, maintaining the predetermined height therefrom, such that the suspension structure can vibrate over the substrate to detect an inertial movement; at least one elastic member connected to the suspension structure, for supporting the suspension structure so that the suspension structure makes an inertial movement; a movable comb having at least one comb finger, the movable comb protruding from the suspension structure; a fixed comb having at least one comb finger, the fixed comb fingers protruding from the substrate opposite to and in mesh with the movable comb fingers; and a power supply
Choi Jae-joon
Jeong Hee-moon
Kang Sung-gyu
Kim Kyu-yong
Lee Ki Bang
Burns Doane Swecker & Mathis L.L.P.
Miller Rose M.
Samsung Electronics Co,. Ltd.
Williams Hezron
LandOfFree
3-Dimensional comb structure and actuator and inertia... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with 3-Dimensional comb structure and actuator and inertia..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and 3-Dimensional comb structure and actuator and inertia... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2603736