KR20150001112A - Inertial Sensor - Google Patents

Abstract

The present invention provides an inertial sensor for buffering an impact. The inertial sensor according to the present invention includes a mass, a flexible beam on which an electrode or a piezoresistance element is arranged and which is combined with the mass, a support unit which is connected to the flexible beam and supports the flexible beam to lift the mass, and a bottom cover which is combined with the support unit to cover the mass. A cushion layer is formed on one side of the bottom cover to face the mass. The cushion layer is formed on a part of the bottom cover.

Description

Inertial Sensor

The present invention relates to an inertial sensor.

Generally, inertial sensors are widely used in automobiles, airplanes, mobile communication terminals, toys, etc., and three-axis acceleration and angular velocity sensors for measuring X-axis, Y-axis and Z-axis acceleration and angular velocity are required. In order to detect minute accelerations High performance and small size.

In addition, the acceleration sensor according to the related art includes a technical feature for converting the movement of the mass and the flexible beam into an electric signal, and the piezo-electric resistance detecting the movement of the mass from the resistance change of the piezoresistive element disposed in the flexible beam And a capacitance type in which the movement of the mass is detected by a change in capacitance between the fixed electrode and the fixed electrode.

And the piezoresistance method uses a device whose resistance value changes by stress. For example, where the tensile stress is distributed, the resistance value increases and the resistance value decreases where the compressive stress is distributed.

As an example of the inertial sensor, a conventional piezoresistive acceleration sensor including prior art documents has a problem that the area of the beam is reduced to increase the sensitivity, so that it is vulnerable to impact, and in particular drop reliability is deteriorated.

US 20060156818A

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an aspect of the present invention to provide a cushion layer in a part of a lower cover opposed to a mass body, Is intended to provide an inertial sensor that performs the function of a stopper to limit excessive displacement of the mass.

An inertial sensor according to an embodiment of the present invention includes a mass body, an electrode or a piezoresistive element, a flexible beam to which the mass is coupled, and a flexible beam connected to the flexible beam, And a lower cover coupled to the support to cover the mass body. A cushion layer is formed on one surface of the lower cover facing the mass body, and the cushion layer is formed in a part of the lower cover.

Further, in the inertial sensor according to an embodiment of the present invention, the cushion layer may be formed on the lower cover so as to correspond to the center portion of the mass body.

Also, in the inertial sensor according to an embodiment of the present invention, the cushion layer may be formed on the lower substrate by patterning a polymer.

Further, in the inertial sensor according to an embodiment of the present invention, the mass includes a central mass, a first peripheral mass formed to extend in four directions around the central mass, a second peripheral mass, a third peripheral mass, Surrounding masses.

In the inertial sensor according to an embodiment of the present invention, a center cushion layer opposed to the center mass, a first peripheral cushion layer opposed to the first peripheral mass, and a second peripheral cushion layer opposed to the second peripheral mass, A third cushion layer opposite the third surrounding mass, and a fourth cushion layer opposite the fourth surrounding mass.

In the inertial sensor according to an embodiment of the present invention, the center cushion layer, the first peripheral cushion layer, the second peripheral cushion layer, the third cushion layer, and the fourth cushion layer may be formed of a polymer, May be patterned and formed on the lower substrate.

The inertial sensor according to an embodiment of the present invention may further include an upper cover coupled to one surface of the flexible beam to cover the electrode or the piezoresistive element.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to this, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may appropriately define the concept of a term in order to best describe its invention The present invention should be construed in accordance with the spirit and scope of the present invention.

According to the present invention, a cushion layer is formed in a part of the lower cover opposite to the mass body to improve the shock absorbing function, and the cushion layer functions as a stopper for restricting excessive displacement of the mass body An inertial sensor can be obtained.

1 is a plan view schematically illustrating an inertial sensor according to an embodiment of the present invention;
2 is a schematic AA 'sectional view of the inertial sensor shown in Fig.
3 is a plan view of a mass and a cushion layer in an inertial sensor according to another embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, specific advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a plan view schematically showing an inertial sensor according to an embodiment of the present invention, and FIG. 2 is a schematic sectional view taken along the line A-A 'of the inertial sensor shown in FIG.

As shown, the inertial sensor 100 includes a flexible beam 110, a mass 120, a support 130, a cushion layer 140, and a bottom cover 150.

The flexible beam 110 is formed in a plate shape and is made of a flexible substrate such as a membrane or a beam having elasticity so that the mass body 120 can cause displacement.

A driving electrode and a sensing electrode may be formed on one surface of the flexible beam 110 to be realized by an angular velocity sensor, or a piezoresistive element 111 may be coupled to be realized as an acceleration sensor.

The mass body 120 is coupled to one surface of the flexible beam 110, and a displacement is generated by an inertial force, an external force, a Coriolis force, a driving force, or the like.

The support part 130 is coupled to one surface of the flexible beam and is supported in a floating state so that the mass body 120 can be displaced.

At this time, the mass body 120 is positioned at a central portion of the flexible beam 110, the support portion 130 is formed in a hollow shape, the mass body 120 is positioned in the hollow portion so as to be displaceable, The support portion 130 is located at the edge of the flexible beam 110, thereby securing a space in which the mass body 120 can cause displacement.

In addition, the mass body 120 may be formed in a square pillar shape, and the support portion 130 may have a cylindrical shape or a square pillar shape. In addition, the shape of the mass body 120 and the support part 130 is not limited thereto, and may be formed in all shapes known in the art.

When an external force is generated, the inertial sensor according to an embodiment of the present invention is implemented as an acceleration sensor. When an external force is generated, the moment is generated by the external force of the mass body 120, The resistance element 111 changes its resistance value by the displacement of the mass body 120, and detects the resistance value to calculate the acceleration.

The lower cover 150 is coupled to one surface of the support 130 to cover the mass body 120. The bonding agent B may be applied to the support 130 to bond the lower cover 150 and the mass body 120 and the lower cover 150 may be coated by the thickness of the bonding agent B. [ Can be determined.

It may also be implemented through patterning of the polymer to join the lower cover and the support. Further, patterning of the polymer enables more accurate design, control, and technology implementation.

A cushion layer 140 is formed on one surface of the lower cover 150 facing the mass body 120. The cushion layer 140 is provided to mitigate impact when the mass body 120 is collided with the lower cover 130 by an external force. Further, The cushion layer 140 also functions as a stopper for restricting excessive displacement of the mass body 120.

The cushion layer 140 is not formed on the front surface of the lower cover 150 so as to be opposed to the mass body 120 but partially formed in a partial region. This takes into consideration the characteristic that the damping force is lowered depending on the area.

1 and 2 illustrate that the cushion layer 140 is formed in a part of the lower cover 150 so as to correspond to the central portion of the mass body 120. As shown in FIG.

The cushion layer 140 may be formed by patterning a polymer.

The flexible beam 110, the mass body 120, and the support 130 may be formed by selectively etching an SOI (Silicon On Insulator) substrate that is easy to process by a MEMS (Micro Electro Mechanical Systems) process.

Thus, a silicon oxide layer (not shown) of the SOI substrate may remain between the mass body 120 and the flexible beam 110 and between the support 130 and the flexible beam 110. However, the flexible beam 110, the mass body 120, and the support 130 are not necessarily formed by etching the SOI substrate, but may be formed by etching a general silicon substrate or the like.

Also, the support part 130 may further include an electrode pad 131 for inputting and outputting a sensing signal.

In addition, the inertial sensor according to an embodiment of the present invention may further include an upper cover coupled to one surface of the flexible beam to cover the driving and sensing electrodes formed on the flexible beam or the piezoresistive element. A bonding agent may be applied to the flexible beam to bond the upper cover, and the thickness of the bonding agent may determine the distance between the flexible beam and the upper cover.

3 is a plan view showing a mass body and a cushion layer in an inertial sensor according to another embodiment of the present invention.

As shown, the inertial sensor according to another embodiment differs from the inertial sensor according to the embodiment only in the shape of the cushion layer. Accordingly, the description of the same technical structure as described above is omitted through the inertial sensor according to one embodiment, and only the shape and organic bonding of the mass and the cushion layer are described.

More specifically, the cushion layer 240 is formed to face the mass body 220 of the inertial sensor according to another embodiment.

The cushion layer is also formed on the center portion and the edge portion of the mass body 220. That is, the mass body 220 includes a center mass 221, a first peripheral mass 222, a second peripheral mass 223, a third peripheral mass 224, and a fourth peripheral mass 225.

The first peripheral mass body 222, the second peripheral mass body 223, the third peripheral mass body 224, and the fourth peripheral mass body 225 are formed to extend in four directions around the center mass.

The cushion layer includes a central cushion layer 241 opposed to the center mass 221, a first peripheral cushion layer 242 opposed to the first peripheral mass 222 and a second peripheral cushion layer 242 opposed to the second peripheral mass 223, A third cushion layer 244 opposed to the third peripheral mass 224 and a fourth cushion layer 245 opposed to the fourth surrounding mass 225. The second peripheral cushion layer 243 includes a second peripheral cushion layer 242,

The polymer may be patterned to form the center cushion layer 241, the first peripheral cushion layer 242, the third peripheral cushion layer 243, and the fourth peripheral cushion layer 245, have.

The first peripheral cushion layer 242, the third peripheral cushion layer 243, and the third peripheral cushion layer 243, when the mass body 220 is displaced beyond the set range due to an external force or the like, The first peripheral cushion layer 242, the third peripheral cushion layer 243, and the fourth peripheral cushion layer 243 are simultaneously damped by the one or more peripheral cushion layers 245 by one or more peripheral cushion layers 245, The peripheral cushion layer 245 is not integrally formed, but is realized with improved damping force as compared with a cushion layer formed of an integral layer.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the same is by way of illustration and example only and is not to be construed as limiting the present invention. It is obvious that the modification and the modification are possible.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

100: inertial sensor 110: flexible beam
120: mass body 130:
131: electrode pad 140: cushion layer
B: bonding portion 221: center mass,
222: first surrounding mass 223: second surrounding mass
224: third surrounding mass 225: fourth surrounding mass
The first peripheral cushion layer 242, the third peripheral cushion layer 243, and the fourth peripheral cushion layer 245,

Claims (7)

Mass;
A flexible beam having electrodes or piezoresistive elements arranged therein, the masses being coupled;
A support coupled to the flexible beam and supporting the flexible beam such that the mass is lifted; And
And a lower cover coupled to the support to cover the mass,
A cushion layer is formed on one surface of the lower cover facing the mass body, and the cushion layer is formed in a part of the lower cover.
The method according to claim 1,
The cushion layer
And the lower cover is formed on the lower cover so as to correspond to a center portion of the mass body.
The method of claim 2,
Wherein the cushion layer is formed on the lower substrate by patterning a polymer.
The method according to claim 1,
Wherein the mass body comprises a center mass and a first peripheral mass, a second peripheral mass, a third peripheral mass, and a fourth peripheral mass formed to extend in four directions around the central mass.
The method of claim 4,
A first peripheral cushion layer opposed to the first peripheral mass, a second peripheral cushion layer opposed to the second peripheral mass, a third cushion layer opposed to the third peripheral mass, and a fourth peripheral cushion layer opposite the third peripheral mass, And a fourth cushion layer opposite the surrounding mass.
The method of claim 5,
Wherein the center cushion layer, the first peripheral cushion layer, the second peripheral cushion layer, the third cushion layer, and the fourth cushion layer are formed on a lower substrate by patterning a polymer.
The method according to claim 1,
Further comprising an upper cover coupled to one surface of the flexible beam to cover the electrode or piezoresistive element.

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