CN113130259B

CN113130259B - Plane unit moving driven bistable MEMS switch

Info

Publication number: CN113130259B
Application number: CN202110463726.9A
Authority: CN
Inventors: 唐彬; 陶启; 兰泽华; 代俊; 王晓红; 廖运来; 唐自励
Original assignee: Institute of Electronic Engineering of CAEP
Current assignee: Institute of Electronic Engineering of CAEP
Priority date: 2021-04-27
Filing date: 2021-04-27
Publication date: 2023-01-24
Anticipated expiration: 2041-04-27
Also published as: CN113130259A

Abstract

The invention discloses a bistable MEMS switch driven by plane single displacement, which comprises a substrate, fixed ends, an elastic beam and a T-shaped trigger actuator, wherein the fixed ends comprise a first fixed end, a second fixed end and a third fixed end; the elastic beams comprise two L-shaped elastic beams and two V-shaped elastic beams. The bistable MEMS switch disclosed by the invention drives the T-shaped trigger actuator through the displacement driving device, and the circuit is powered on and powered off by utilizing the deformation and displacement of the elastic beam. The bistable MEMS switch driven by the plane single displacement, disclosed by the invention, has the advantages of less input drive, simple structure, easiness in control, high response speed, self-locking function and high reliability, can be used as a circuit switch and also can be used as a displacement switch, and has strong universality.

Description

Plane unit moving driven bistable MEMS switch

Technical Field

The invention belongs to the field of micro-electro-mechanical systems, and particularly relates to the field of MEMS switches.

Background

The MEMS switch is one of typical applications of MEMS technology, is a result of miniaturization design and manufacture of the traditional electromechanical switch, provides powerful guarantee for the development of high-performance circuit systems, and has wide and urgent application requirements on the aspect of circuit control in important fields of modern communication, aerospace, biomedical science, national defense military industry and the like.

A bistable MEMS switch is one of the MEMS switches that requires actuator actuation only during state transitions. Chinese patent publication No. CN107742598A discloses an electro-thermally driven bistable MEMS switch, which is driven by V-shaped electro-thermal actuators I and II vertically distributed on a square substrate to complete the contact and non-contact of a first hook-shaped contact and a second hook-shaped contact, i.e., to turn on and off a circuit. Chinese patent publication No. CN110600289A discloses a resettable MEMS bistable flip-flop which realizes setting and resetting of a switch by controlling actuator input displacement, and the bistable MEMS switch requires the actuator to input two different and more accurate displacement amounts in setting and resetting, and has the problems of great control difficulty and low control efficiency.

Therefore, a new bistable MEMS switch is urgently needed to solve the problems of high control difficulty and low control efficiency of the bistable MEMS switch in the prior art.

Disclosure of Invention

In view of this, the present invention provides a planar single-displacement driven bistable MEMS switch, which can realize the switching state inversion only by single-displacement input, and has the advantages of simple structure, easy control, and fast response speed.

In order to achieve the purpose, the invention adopts the following technical scheme: a planar unit displacement driven bistable MEMS switch comprises a substrate and further comprises:

a fixed end, the fixed end including: the first fixing end, the second fixing end and the third fixing end are arranged on the base;

the first fixed end and the second fixed end are vertically arranged on the substrate;

the third fixed end is arranged on the substrate and is positioned below the first fixed end and the second fixed end, and the upper side surface of the third fixed end is provided with a boss;

the upper surface of the boss is provided with a conductive contact;

the elastic beam is connected with the first fixed end and the second fixed end and is provided with a suspended end;

the suspension end comprises a first suspension end, a second suspension end and a third suspension end;

the T-shaped trigger actuator is positioned below the third fixed end and comprises a displacement input connecting rod in the vertical direction and a trigger rod in the horizontal direction;

the end surface of the right end of the trigger rod of the T-shaped trigger actuator 8 is higher than the end surface of the left end;

the first suspension end and the third suspension end are positioned above two end parts of the trigger rod of the T-shaped trigger actuator in the horizontal direction;

the second free end is a conductive contact and is located on the right side of the boss of the third fixing end in a natural state, but is not in contact with the right side wall of the boss of the third fixing end.

The first fixed end, the second fixed end, the third fixed end and the elastic beam are electric conductors.

Preferably, the elastic beam includes:

one end of the first L-shaped elastic beam is connected with the second fixed end, and the other end of the first L-shaped elastic beam is a second suspended end;

one end of the first V-shaped elastic beam is connected with the first fixed end, and the other end of the first V-shaped elastic beam is a first suspended end;

one end of the second L-shaped elastic beam is connected with the first L-shaped elastic beam, and the other end of the second L-shaped elastic beam is connected with the first V-shaped elastic beam;

and one end of the second V-shaped elastic beam is connected with the first L-shaped elastic beam, and the other end of the second V-shaped elastic beam is a third suspension end.

Preferably, a protrusion is arranged on the outer side of the middle of the first V-shaped elastic beam.

Preferably, the V-shaped included angle of the first V-shaped elastic beam is smaller than the V-shaped included angle of the second V-shaped elastic beam.

Preferably, the surfaces of two ends of a trigger rod of the T-shaped trigger actuator are respectively provided with a left guide bulge and a right guide bulge, the right side of the left guide bulge is provided with a limit groove, and the right side of the right guide bulge is provided with a pushing boss.

Preferably, the left guide protrusion and the right guide protrusion are both triangular.

Preferably, the lower surfaces of the first fixing end, the second fixing end and the third fixing end are provided with anchor ends protruding downwards.

Preferably, the displacement input connecting rod is connected with any one driving device for generating displacement.

Preferably, the MEMS switch may be implemented as an electrical switch or an optical switch.

Preferably, the T-shaped trigger actuator and the elastic beam are positioned in the same plane

The invention has the beneficial effects that: the bistable MEMS switch driven by the plane single displacement can realize the turning of the switch state only by single displacement input, and has the advantages of less input drive, simple structure, easy control and high response speed; when the bistable MEMS switch is in a power-on state, the second suspension end and the boss 3-2 have a self-locking function, and both are under the action of pressure when in contact, so that the bistable MEMS switch has large contact force and high structural strength, can stably keep a good conduction state, and has strong reliability; the bistable MEMS switch can be used as a circuit switch and also can be used as a displacement switch, and has strong universality.

Drawings

FIG. 1 is a schematic diagram of the open state of a planar unit displacement driven bistable MEMS switch circuit according to the present invention;

FIG. 2 is a schematic diagram of the ON state of the planar unit displacement driven bistable MEMS switch circuit of the present invention;

FIG. 3 is a cross-sectional view of a first fixed end of a planar unit displacement driven bistable MEMS switch of the present invention;

FIG. 4 is a schematic structural diagram of a T-shaped trigger actuator of a bistable MEMS switch driven by a planar unit displacement according to the present invention;

in the figure: 1. the first fixing end 2, the second fixing end 3, the third fixing end 4, the first L-shaped elastic beam 5, the second L-shaped elastic beam 6, the first V-shaped elastic beam 7, the second V-shaped elastic beam 8. T-shaped trigger actuator 3-2, the boss 6-1, the first free end 6-2, the boss 4-1, the second free end 7-1, the third free end 8-1, the left guide boss 8-2, the right guide boss 8-3, the limiting groove 8-4, the pushing boss 8-5 and the displacement input connecting rod.

Detailed Description

It will be appreciated by those of ordinary skill in the art that the embodiments described herein are intended to assist the reader in understanding the principles of the invention and are to be construed as being without limitation to such specifically recited embodiments and examples. Those skilled in the art can make various other specific changes and combinations based on the teachings of the present invention without departing from the spirit of the invention, and these changes and combinations are within the scope of the invention.

The invention is described in detail below with reference to the figures and specific embodiments.

A planar single-displacement actuated bistable MEMS switch as shown in fig. 1 and 2, comprising: the substrate, the fixed end, the elastic beam and the T-shaped trigger actuator 8.

The above-mentioned stiff end includes: a first fixed end 1, a second fixed end 2 and a third fixed end 3; wherein the first fixing end 1 and the second fixing end 2 are vertically arranged on the substrate, the third fixing end 3 is arranged on the substrate and is positioned below the first fixing end 1 and the second fixing end 2, as shown in figure 1, the upper side surface of the third fixing end 3 is provided with a boss 3-2, and the upper surface of the boss 3-2 is provided with a conductive contact.

The elastic beam includes: two L type elastic beam and two V type elastic beam are: a first L-shaped spring beam 4, a second L-shaped spring beam 5, a first V-shaped spring beam 6 and a second V-shaped spring beam 7. One end of the first L-shaped elastic beam 4 is connected with the second fixed end 2, and the other end of the first L-shaped elastic beam is a second suspended end 4-1; one end of the second L-shaped elastic beam 5 is connected with the first L-shaped elastic beam 4, and the other end is connected with the first V-shaped elastic beam 6; one end of the first V-shaped elastic beam 6 is connected with the first fixed end 1, and the other end of the first V-shaped elastic beam is a first suspended end 6-1; one end of the second V-shaped elastic beam 7 is connected with the first L-shaped elastic beam 4, and the other end of the second V-shaped elastic beam is a third suspension end 7-1. The elastic beam connects the first fixing end 1 and the second fixing end 2.

The outer side of the middle part of the first V-shaped elastic beam 6 is provided with a bulge 6-2, and the V-shaped included angle of the first V-shaped elastic beam 6 is smaller than the V-shaped included angle of the second V-shaped elastic beam 7.

The first hanging end 6-1 and the third hanging end 7-1 are positioned above two end parts of the trigger rod of the T-shaped trigger actuator 8 in the horizontal direction; the second free end 4-1 is a conductive contact which is located on the right side of the boss 3-2 in a natural state, i.e. a circuit breaking state, but is not in contact with the right side wall of the boss 3-2.

As shown in fig. 4, the T-shaped trigger actuator 8 is located below the third fixing end 3, and includes a vertical displacement input connecting rod 8-5 and a horizontal trigger rod, wherein the two end surfaces of the horizontal trigger rod are respectively provided with a left guide protrusion 8-1 and a right guide protrusion 8-2, the right side of the left guide protrusion 8-1 is provided with a limiting groove 8-3, and the right side of the right guide protrusion 8-2 is provided with a pushing boss 8-4. In the present embodiment, both the left guide protrusion 8-1 and the right guide protrusion 8-2 are set to be triangular, and the left guide protrusion 8-1 and the right guide protrusion 8-2 may be set to have other shapes with a guide function, such as a trapezoid shape, a cone shape, and the like. The left guide projection 8-1 and the right guide projection 8-2 play a role in guiding and limiting the moving direction of the first free end 6-1 and the third free end 7-1.

The right end face of the T-shaped trigger actuator 8 is higher than the left end face, so that the third free end 7-1 is pushed first when the T-shaped trigger actuator 8 moves upward.

The T-shaped trigger actuator 8 and all the elastic beams are in the same horizontal plane.

The lower surfaces of the first fixed end 1, the second fixed end 2 and the third fixed end 3 of the present embodiment all have the anchor ends protruding downward as shown in fig. 3, increasing the distance between the 3 fixed ends and the elastic beam and the substrate, thereby increasing the space for deformation of the elastic beam.

The plane single-displacement driven bistable MEMS switch disclosed by the invention can be connected with any driving device for generating displacement.

The plane single-displacement driven bistable MEMS switch can be used as a circuit switch or a displacement switch, such as an electric switch or an optical switch.

The working flow of the planar single-displacement driven bistable MEMS switch of the embodiment is as follows:

1. electrifying the circuit

When the T-shaped trigger actuator 8 is driven to displace by the external displacement driving device connected to the displacement input connecting rod 8-5, the T-shaped trigger actuator 8 moves upwards, the right end of the T-shaped trigger actuator pushes the third free end 7-1, so that the second V-shaped elastic beam 7 is extruded to drive the first L-shaped elastic beam 4 to move upwards, and then the second free end 4-1 of the first L-shaped elastic beam 4 deforms and displaces to the upper surface of the boss 3-2 of the third fixed end 3 to be in electric contact with the boss 3-2, and a circuit is switched on. Meanwhile, the first V-shaped elastic beam 6 bends rightwards due to the action of the second L-shaped elastic beam 5, the first free end 6-1 of the first V-shaped elastic beam 6 cannot move rightwards and is attached to the left side wall of the left guide salient angle 8-1 due to the limitation of the left side wall of the left guide salient angle 8-1 of the T-shaped trigger actuator 8, and the third free end 7-1 at the tail end of the second V-shaped elastic beam 7 cannot move leftwards due to the limitation of the right guide salient angle 8-2 of the T-shaped trigger actuator 8. At this time, the displacement drive of the T-shaped trigger actuator 8 is removed, the T-shaped trigger actuator 8 moves downward, the first L-shaped elastic beam 4 and the second L-shaped elastic beam 5 release the force of deformation generated by the upward displacement of the first V-shaped elastic beam 6, and at this time, the second hanging end 4-1 is pressed against the upper surface of the boss 3-2 by the deformation force released by the first L-shaped elastic beam 4 and the second L-shaped elastic beam 5 and stops moving, so that energization is realized, and self-locking with the upper surface of the boss 3-2 is realized, as shown in fig. 2.

2. Circuit breaking

When the T-shaped trigger actuator 8 is input to drive displacement again by the external displacement driving device connected to the displacement input connecting rod 8-5, the T-shaped trigger actuator 8 moves upwards, the left end of the T-shaped trigger actuator firstly pushes the first free end 6-1 located in the limiting groove 8-3 to move upwards, the first free end 6-1 and the first fixed end 1 extrude the first V-shaped elastic beam 6 to deform the first V-shaped elastic beam towards the outer side of the V shape, the bulge 6-2 pushes the first L-shaped elastic beam 4 to move rightwards, the second free end 4-1 is enabled to completely leave the upper side wall of the boss 3-2, and the circuit is disconnected. Meanwhile, the third free end 7-1 of the second V-shaped elastic beam 7 is positioned on the left side of the right guide convex angle 8-2, so that the second free end 4-1 cannot be influenced by the pushing boss 8-4 to move to the right due to no upward pushing. At this time, the displacement drive of the T-shaped trigger actuator 8 is removed, and the second suspension end 4-1 continues to move downwards under the action of the deformed first L-shaped elastic beam 4 and the deformed second L-shaped elastic beam 5 until the second suspension end is completely reset, as shown in fig. 1.

The purpose of setting the V-shaped included angle of the first V-shaped elastic beam 6 to be smaller than the V-shaped included angle of the second V-shaped elastic beam 7 in the invention is to ensure that the first V-shaped elastic beam 6 has larger deformation when the first V-shaped elastic beam 6 and the second V-shaped elastic beam 7 are pushed upwards by the T-shaped trigger actuator 8, so as to push the second suspension end 4-1 to leave the boss 3-2, while the second V-shaped elastic beam 7 hardly deforms when being squeezed, and most of the displacement is transferred to the first L-shaped elastic beam 4 connected with the second V-shaped elastic beam.

In the application process of the invention, the first suspension end 6-1 on the first V-shaped elastic beam 6 needs to be ensured to be limited by the left side wall of the left guide convex angle 8-1 of the T-shaped trigger actuator 8 to move rightwards in the circuit connection process, and the displacement is released after the circuit connection process is finished, so that the first suspension end 6-1 moves to the position above the limiting groove 8-3 of the T-shaped trigger actuator 8; the third hanging end 7-1 on the second V-shaped elastic beam 7 is located on the left side of the left guide convex angle 8-2 of the T-shaped trigger actuator 8 after the circuit connection process is completed, and the third hanging end 7-1 cannot be pushed by the pushing boss 8-4 of the T-shaped trigger actuator 8 in the circuit disconnection process.

In the fabrication of the planar single-displacement driven bistable MEMS switch of the present invention, since most MEMS chip processes are aimed at fabricating a movable structure on a substrate, the present resettable MEMS bistable flip-flop is suitable for any MEMS process that can fabricate a movable structure on a substrate.

Here, a manufacturing method of a bistable MEMS switch will be described by taking a silicon structure process using an SOI silicon wafer as an example, and specifically includes the following steps:

1. photoetching an integral structure pattern of the bistable MEMS switch on an SOI (silicon on insulator) silicon chip, and etching the outer part of the structure pattern to an oxide layer;

2. and placing the structural pattern in a buffer oxide etching solution to enable the etching oxide layer to be exposed out of the substrate, then continuously etching until the lower part of the elastic beam is completely etched, and incompletely etching the lower part of the fixed end to form a fixed end anchor end, a fixed end fixed on the anchor end, an elastic beam connected to the side wall of the fixed end and with a suspended bottom and a T-shaped trigger actuator connected to the elastic beam for providing displacement input.

Claims

1. A planar unit motion actuated bistable MEMS switch comprising a substrate, wherein said bistable MEMS switch further comprises:

a fixed end, the fixed end including: a first fixed end (1), a second fixed end (2) and a third fixed end (3); the first fixed end (1) and the second fixed end (2) are vertically arranged on the substrate;

the third fixed end (3) is arranged on the substrate and is positioned below the first fixed end (1) and the second fixed end (2), and a boss (3-2) is arranged on the upper side surface of the third fixed end;

the upper surface of the boss (3-2) is provided with a conductive contact;

the elastic beam is connected with the first fixed end (1) and the second fixed end (2) and is provided with a suspended end; the suspension end comprises a first suspension end (6-1), a second suspension end (4-1) and a third suspension end (7-1); the T-shaped trigger actuator (8) is positioned below the third fixed end (3) and comprises a displacement input connecting rod (8-5) in the vertical direction and a trigger rod in the horizontal direction;

the end surface of the right end of a trigger rod of the T-shaped trigger actuator (8) is higher than the end surface of the left end;

the first suspension end (6-1) and the third suspension end (7-1) are respectively positioned above two ends of a trigger rod of the T-shaped trigger actuator (8);

the second free end (4-1) is a conductive contact and is positioned on the right side of the boss (3-2) in a natural state, but is not contacted with the right side wall of the boss (3-2);

the first fixed end (1), the second fixed end (2), the third fixed end (3) and the elastic beam are all electric conductors;

the elastic beam includes:

one end of the first L-shaped elastic beam (4) is connected with the second fixed end (2), and the other end of the first L-shaped elastic beam (4) is a second suspended end (4-1);

one end of the first V-shaped elastic beam (6) is connected with the first fixed end (1), the other end of the first V-shaped elastic beam (6) is a first suspended end (6-1), a bulge (6-2) is arranged on the outer side of the middle of the first V-shaped elastic beam (6), and a V-shaped included angle of the first V-shaped elastic beam (6) is smaller than a V-shaped included angle of the second V-shaped elastic beam (7);

one end of the second L-shaped elastic beam (5) is connected with the first L-shaped elastic beam (4), and the other end of the second L-shaped elastic beam (5) is connected with the first V-shaped elastic beam (6);

one end of the second V-shaped elastic beam (7) is connected with the first L-shaped elastic beam (4), and the other end of the second V-shaped elastic beam (7) is a third suspension end (7-1);

the surface of two ends of a trigger rod of the T-shaped trigger actuator (8) is respectively provided with a left guide bulge (8-1) and a right guide bulge (8-2), the right side of the left guide bulge (8-1) is provided with a limit groove (8-3), and the right side of the right guide bulge (8-2) is provided with a pushing boss (8-4); the first free end (6-1) is positioned above the left guide bulge (8-1), and the third free end (7-1) is positioned above the right guide bulge (8-2).

2. The planar single-displacement driven bistable MEMS switch of claim 1, wherein said left guide protrusion (8-1) and right guide protrusion (8-2) are each triangular shaped.

3. The planar single-displacement driven bistable MEMS switch of claim 1, wherein the lower surfaces of the first fixed end (1), the second fixed end (2) and the third fixed end (3) are all provided with downward convex anchor ends.

4. The planar single-displacement driven bistable MEMS switch according to claim 1, wherein the displacement input connecting rod (8-5) is connected to any one of the driving devices generating displacement.

5. The planar single displacement actuated bistable MEMS switch of claim 1, wherein said MEMS switch is configured as a circuit switch or a displacement switch.

6. The planar single-displacement driven bistable MEMS switch of claim 1, wherein the T-shaped trigger actuator (8) and the elastic beam are located on the same plane.