The MEMS electromagnetic relay
Technical field
The present invention relates to a kind of electromagnetic relay, belong to microrelay (Micro Relay) and MEMS technology (MicroElectro-Mechanical System) field.
Background technology
Relay is widely used in other various automatic control equipments of Aero-Space, military electronics, information industry and national economy, it is one of most important control element, basically all automatic control systems all will be used relay, and traditional relay mainly is divided into electromechanical relay and solid-state relay two big classes.Along with digitlization, arrival of information age, automatic control system to the demand of relay gradually to microminiaturization, integrated, the intelligent direction development, and that electromechanical relay has switching speed is slow, production efficiency is low, volume is big, shortcomings such as the easy wearing and tearing in contact, solid-state relay has can not realize control end and switch terminals isolation, conducting resistance is big, shortcomings such as leakage current is big, the outstanding shortcoming of traditional relay has hindered some to the relay microminiaturization, intelligent, integrated demanding robot control system(RCS), as miniature aerospace vehicles such as microsatellites, and automatic detection instrument (ATE).
Midget relay (being called for short the MEMS relay) based on the MEMS technology is an emerging research field, from first MEMS relay birth of later 1970s, has a lot of research institutions successively to carry out correlative study afterwards in the world.Some research institutions and the company of countries and regions such as USA and Europe day have made important progress, for example U.S. Lincoln laboratory, Munich, Germany engineering college, AD company, and the maturation that has is converted into product.Domestic relevant institute has also obtained certain achievement aspect correlative study.
The MEMS relay has structurally carried out merging to traditional relay and is microminiaturized, combines advanced micro-/ nano technology and micro-processing technology on technology.The MEMS relay of present research mainly is divided into three major types according to operation principle: electrostatic, pattern of fever and electromagnetic type, also have pyromagnetic type, electromagnetism static mixed type, liquid contact type etc. in addition, and back three kinds of researchers are less.The invention belongs to MEMS relay field.
MEMS electrostatic relay, general using electrostatic force make float electrode crooked or reverse, and finish switch motion thereby cause movable contact electrode integrated on the float electrode to contact with fixing contact electrode.Electrostatic force is face power, and therefore electrostatic force that produces and pole plate area and driving voltage have direct relation, because relay construction is small-sized, therefore the electrostatic force that produces is also little, causes contact resistance very big.The float electrode of MEMS electrostatic relay mainly contains three kinds of forms such as cantilever beam, beam with both ends fixed, torsion beam, and the driving voltage of cantilever beam structure is little, switching speed is fast, power consumption is little, conducting resistance is little, therefore is most widely used.No matter which kind of float electrode structure the MEMS electrostatic relay adopts, increasing attraction need be by increasing the pole plate area or improving driving voltage, the former can cause, and physical dimension increases, the latter will cause driving voltage to increase, therefore need isolate high voltage, cause the application system cost to rise, even can't in integrated circuit, use.
The MEMS thermal relay utilizes the volume expansion principle, only needs very low driving voltage (being generally 3V-5V) just can produce bigger contact force, therefore be applicable to the IC circuit, but power consumption is big than electromagnetic type and electrostatic.The intrinsic hysteresis quality of volume expansion effect has determined that its response speed is low.Be at least the switching time of MEMS thermal relay severally, become the main cause that hinders its extensive use, but be applicable to the place not high the switch rate request to the hundreds of microsecond.
The MEMS electromagnetic relay utilizes MEMS technology, the generation magnetic field function and the magnetic force carrier function that mainly utilize coil and soft magnetic material and hard magnetic material to have.The generation form in MEMS electromagnetic relay magnetic field plays crucial decisive action to the structure of relay, generally be to be produced by hot-wire coil or permanent magnet, and soft magnetic bodies and permanent magnet is usually as the magnetic force carrier, specifically makes up according to different structure and different.The magnetic circuit of MEMS electromagnetic relay is formed and is made up of coil and this three classes material combining form such as permanent magnet, coil and soft magnetic bodies, coil and soft magnetic bodies and permanent magnet etc. usually.Preceding two kinds of forms produce magnetic field by hot-wire coil, therefore, keep operating state if desired for a long time, thereby just need to give coil electricity to produce the magnetic field that continues always, power consumption is just bigger comparatively speaking, also can continue to produce heat in addition, may be influential to operational environment.For example, in ATE, need use multicircuit relay carries out multichannel data and obtains and export, therefore low-power consumption is very necessary, equally for minitype spacecraft, basic all robot control system(RCS) itself all to use relay and the self-condition decision it can not carry the too much energy, so it is that volume is little and low in energy consumption to the demand of relay.
Optimal structure is the third combination of materials form, and coil and permanent magnet all can produce magnetic field, simultaneously makes the magnetic force carrier by soft magnetic bodies, and the state of latching relay is come in the magnetic field that can continue to utilize permanent magnet to produce after the of short duration energising of coil.
There is following problems in existing MEMS electromagnetic relay:
1. power consumption height.If the MEMS electromagnetic relay needs coil to switch on to the operating state of latching relay, so the long-play power consumption is considerable always.Long-time energising heats up hot-wire coil, causes the relay interior environment temperature to raise, and influences the magnetic characteristic of magnetic material, thereby further influences the relay service behaviour.The important applied field of MEMS electromagnetic relay is miniature aerospace vehicle, ATE, power consumption is required all than higher, the former energy and the restricted needs of applied environment adopt the relay of low-power consumption as far as possible, the latter needs the various signals of the harmless switching of big array relay, relay is arranged in the very little space by intensive, coil produces a large amount of caloric requirement volatilizations, and low-power relay always is the target that the ATE relay is pursued.
2. poor reliability.MEMS electromagnetic device driver all is a micron dimension generally, if having only a stable state, when power supply instability or other external disturbance, causes relay status to change, thereby causes system to make mistakes.
3. cost height.Processing step is numerous and diverse, and it is very high to cause producing in batches cost, is unfavorable for large-scale production.
Summary of the invention
The objective of the invention is to invent a kind of MEMS electromagnetic relay simple in structure, but make it have simple in structure, characteristics such as switching speed is fast, volume is little, low in energy consumption, high large scale array of reliability.
The invention provides a kind of MEMS electromagnetic relay, described relay adopts three-decker, is upper strata silicon base, lower floor's silicon base, permanent magnet from top to bottom successively; Described upper strata silicon base and lower floor's silicon base two parts bonding, described permanent magnet are bonded on described lower floor silicon base below;
Described upper strata silicon base hollow middle turned round beam by two and is supported one and turn round plate and form and rock structure; The described plate of turning round is a sandwich construction, and wherein the one deck in the face of lower floor's silicon base is movable contact electrode;
Be provided with two planar spiral windings in the groove on described lower floor silicon base surface, on described two planar spiral windings, be coated with insulating barrier, insulating barrier is provided with two pairs of fixedly contact electrodes, every pair fixedly contact electrode contain the independently fixing contact electrode of two spaces; Described two pairs fixedly contact electrode be located at the described upright projection both sides of central axis on described insulating barrier of turning round beam respectively; Described movable contact electrode always keeps stable with a pair of fixedly contact electrode and contacts, promptly two pairs fixedly contact electrode always keep the state of a pair of conducting, other a pair of disconnection.
In the present invention, in the described sandwich construction of turning round plate one deck being arranged is soft magnetic material.
In the present invention, described planar spiral winding is a rectangle, promptly adjacent two sections vertical.
In the present invention, described two planar spiral windings can adopt the mirror image mode that is connected in parallel, and two planar spiral windings are around on the contrary, present the mirror image layout, the outer input of described two planar spiral windings is corresponding to be connected, and interior input is corresponding to link to each other, respectively as two inputs of relay;
In the present invention, described two planar spiral windings also can employing the order series system, two planar spiral windings are around to identical, two outer input correspondences of described two planar spiral windings are connected, two interior inputs are as two inputs of relay.
In the present invention, described two planar spiral windings also can employing the order series system, two planar spiral windings are around to identical, two interior input correspondences of described two planar spiral windings are connected, two outer inputs are as two inputs of relay.
Advantage of the present invention is: relay has bi-stable function, and power consumption is little, the reliability height.Compare with existing MEMS bistable electro magnetic relay, the present invention has following characteristics: 1) response speed is fast; 2) way of contact is the vertical way of contact; 3) float electrode motion spacing is big.
Description of drawings
Fig. 1 is the overall structure schematic diagram of MEMS electromagnetic relay.
Fig. 2 is the longitudinal section of MEMS electromagnetic relay.
Fig. 3 is the vertical view that rocks structure.
Fig. 4 is around to opposite coil layout schematic diagram.
Fig. 5 is around to identical coil schematic layout pattern.
Fig. 6 is for fixedly contact electrode and movable contact electrode position concern schematic diagram.
Embodiment
Specify the present invention below in conjunction with accompanying drawing.
Fig. 1 has shown the overall structure of MEMS electromagnetic relay of the present invention, and described relay adopts three-decker, is upper strata silicon base 1, lower floor's silicon base 2, permanent magnet 3 from top to bottom successively.Upper strata silicon base 1 and lower floor's silicon base 2 two parts bondings, permanent magnet 3 is bonded on lower floor's silicon base 2 belows, by pasting or the electro-plating method realization.The vertical lower floor of the direction of magnetization of permanent magnet 3 silicon base 2 surfaces, promptly lower floor's silicon base 2 lower surfaces engage with the N pole-face or the S pole-face of permanent magnet 3, and as shown in Figure 1, lower floor's silicon base 2 lower surfaces engage with the N pole-face.
Upper strata silicon base 1 is a hollow structure, middle turn round beam 5 by two and supports one and turn round plate 4 and form and rock structure, turns round plate 4 and is sandwich construction, in the face of one deck of lower floor's silicon base is movable contact electrode 12.The wherein end that two identical turns round beam 5 respectively with vertical linking to each other of inwall of upper strata silicon base 1, the two other end respectively with turn round 4 vertical linking to each other of plate, turn round beam 5 with two that turn round plate 4 coplanar is not vertical links to each other, these two faces are parallel to each other, two free ends turning round plate 4 are positioned at turns round beam 5 both sides.
Fig. 2 has shown the vertical section structure of relay in detail.As can be seen from Figure 2, turning round plate 4 and be sandwich construction, is soft magnetic material 9, other material layer 11, movable contact electrode 12 from top to bottom successively, and other material layer 11 can exchange with soft magnetic material 9 positions.Other material layer 11 can be by layer of material, for example silicon or polysilicon; Also can form by the above material of one deck, for example, gold, silicon or chromium, gold, silicon or the like.Turning round plate 4 also can only be made up of soft magnetic material 9 and movable contact electrode 12.Soft magnetic material 9 coercive forces are more little to be suitable for the present invention more, and for example permalloy, Ni are that optimum soft magnetic material of the present invention is selected.Fig. 3 is the vertical view that rocks structure, and A-B is a central axis of turning round beam 5, when turning round beam 5 and being subjected to moment loading, is rotated around A-B, turns round plate 4 also along with the rotation that respective direction takes place.Turning round beam 5 materials can be silicon, polysilicon or metal, for example gold.The material of movable contact electrode 12 is metal or alloy, and is for example golden, AuNi5.
Lower floor's silicon base 2 has the surface to have groove, and fixedly contact electrode 7 of two coils and two pairs is arranged in the groove, and the central axis of turning round beam respectively has a coil and a pair of fixedly contact electrode in the upright projection both sides of groove surfaces.Two coils are that first planar spiral winding 8,6, two coils of second planar spiral winding are positioned on second insulating barrier 10 respectively, under first insulating barrier 14.Second insulating barrier 10 is positioned on the groove bottom land surface, and effect is to guarantee two coils and 2 insulation of lower floor's silicon base, and the effect of first insulating barrier 14 is whole inputs of drawing two coils.Two pairs fixedly contact electrode 7 be positioned on first insulating barrier 14, every pair fixedly contact electrode all contain a pair of fixedly contact electrode that is provided with mutually spacing in the middle of independently, with this fixing contact electrode is linked to each other respectively by two inputs of the circuit of relay control.Two pairs fixedly contact electrode always keep the state of wherein a pair of conducting, other a pair of disconnection.
First planar spiral winding 8, second planar spiral winding 6 are rectangle, promptly adjacent two sections vertical, be that individual layer or sandwich construction all can.First planar spiral winding 8 and second planar spiral winding 6 can adopt following connected mode: order series connection (two kinds) or mirror image parallel connection.Lead-in wire electrode 13 is drawn the inside and outside input of first planar spiral winding 8, second planar spiral winding 6 by the through hole on first insulating material, 14 correspondence positions and is connected, and first planar spiral winding 8 is connected with the mode of second planar spiral winding 6 with order series connection (two kinds) and mirror image parallel connection.
The mirror image parallel connection: first planar spiral winding 8 and second planar spiral winding 6 are around on the contrary, present the mirror image layout, outer input links to each other respectively by corresponding lead-in wire electrode with interior input, and do two inputs of relay respectively, as Fig. 4, the first input end and second input of 101 and 102 difference indicating relays.
Order series connection (first kind), first planar spiral winding 8 and second planar spiral winding 6 are around to identical, outer input links to each other by the lead-in wire electrode, two interior inputs are done two inputs of relay by the lead-in wire electrode, Fig. 5 is the continuous form of interior input, 101 indication first input ends, 102 indications, second input.
Order series connection (second kind), first planar spiral winding 8 and second planar spiral winding 6 are around to identical, and interior input links to each other by the lead-in wire electrode, and two outer inputs are done two inputs of relay by the electrode that goes between.
Two pairs of fixing arbitrary width that the fixing interelectrode distance of contact electrode are not more than movable contact electrode 12 in the contact electrode 7.Wherein, every pair of fixing contact electrode fixing contact electrode of independently metal of comprising two spaces.Among Fig. 6,7a and 7b indicate the fixing contact electrode of two independent metals in a pair of fixedly contact electrode respectively, and the loop that 201 indications are subjected to relay control causes movable contact electrode 12 to move downward when turning round beam 5 rotations, and final fixing contact electrode is stablized when contacting the loop conducting with this simultaneously.
Relay of the present invention is the bistable state form, and the pair of contact closure is promptly always arranged; Before two planar spiral windings are not switched on, soft magnetic material 9 magnetizes and is subjected to the effect of magnetic field moment under the permanent magnetic field effect, driving the whole plate 4 of turning round twists around turning round beam 5 central axis, cause the movable breaker point utmost point 12 and two pairs of fixing a pair of contacts in the contact electrode 7, make and this controlled loop conducting that fixing contact electrode is linked to each other; When the controlled circuit state need change, the electric current of two pairs of logical certain orientations of planar spiral winding, make soft magnetic material 9 magnetic reversals, under the effect of permanent magnetic field, cause the movable breaker point utmost point 12 and two pairs of fixing other a pair of contacts in the contact electrode 7, after relay status was stable, the electric current of two planar spiral windings removed, and relay status keeps.