Electronically switching latching micro-magnetic relay and method of operating same

ES 2 249 409 T3

DESCRIPTION

Micro-magnetic latching relay with electronic commutation and its operating method.

Field to which the invention belongs

The present invention relates generally to relays or inverters. More specifically, the present invention relates to micro-magnetic latching relays with low consumption capacity and to the methods for the development and operation of said micro-magnetic relays.

Description of the invention

Relays typically consist of electronically controlled dual-phase devices that turn on and off electrical contacts intended for the operation of devices in electrical circuits. Described another way, relays generally function as switches that turn on or off sections of electrical, optical, or other devices. Relays are commonly used in many applications spanning telecommunications, radio frequency (RF) communications, portable and consumer electronic devices, industrial and aerospace electronic devices, and other systems.

Although the first relays consisted of mechanical or semiconductor devices, recent technological developments on mechanical-microelectric systems (MEMS) and microelectronics have made possible the production of micro-magnetic and micro-electrostatic relays. Said micro-magnetic relays normally comprise an electromagnet that excites an armature to activate or deactivate an electrical contact. When the magnet stops receiving current, a spring or other mechanical device returns the armature to the rest position. However, these relays tend to suffer from several obvious disadvantages, since in general they only present a single stable output (for example, the rest state) and do not act as latches (they do not maintain a constant output flow, since it is eliminated relay power). In addition, the springs required by conventional micro-magnetic relays can deform or deteriorate over time.

In US Patent No. 5,847,631 to Taylor et al. December 8, 1998 describes another type of micro-magnetic relay. This relay comprises a fixed magnet and an electromagnet designed to generate a magnetic field that intermittently opposes the field generated by the fixed magnet. Although this relay is intended to be bistable, it is required in its case that the electromagnet consumes energy to maintain a minimum of one of the output states. In addition, the amount of energy required to generate the opposite field would be considerable, a fact that would invalidate the use of such a relay in space, in portable electronic devices and in other applications that require low energy consumption.

Consequently, it has become necessary to design a bistable latching relay that does not require power to maintain the states. Furthermore, such a relay must be reliable, simple in design and low cost, and simple to manufacture. In EP-A1093141 published 04-18-2001, a MEMS latching microrelay including magnetic actuators is described. Document US-A-5475353 describes a micro-magnetic latching device in accordance with the preamble of claim 1.

Summary of the invention

According to different models of the invention, a properly constituted relay should have an open state and a closed state. The operation of the relay is produced by means of a console sensitive to magnetic fields, in such a way that said console has an initial state that corresponds to the open state of the relay, and a second state that corresponds to the closed state of the relay. An initial magnetic field may be produced to cause a magnetic moment in the console, and the latter may switch from the initial state to the second state by means of a second magnetic field that could be generated, for example, by a conductor deposited on a substrate of the relay.

Brief description of the charts

The characteristics and advantages mentioned above over the present invention are described below by means of a detailed description of the corresponding illustrative models to be examined together with the attached graphics, and in which the same reference digits are used to identify the same part or similar of equivalent models:

Figure 1 shows the side view of the prototype model corresponding to a latching relay.

Figure 1B shows the top view of the prototype model of a latching relay.

Figures 2A-H show the side view of a technical prototype for the manufacture of a latching relay.

Figure 3A shows the side view of a second prototype model of a latching relay.

Figure 3B shows the top view of a second prototype model of a latching relay.

Figure 3C consists of the perspective view of a prototype console suitable to be used together with a second prototype model of a latching relay.

Figure 4A is the side view of a third prototype model of a latching relay.

Figure 4B is the top view of a third prototype latching relay model.

Figures 4C and 4D consist of the perspective view of a prototype console suitable to be used together with a third prototype model of a latching relay, and

Figure 5 is a side view of a fourth prototype model of a latching relay.

Detailed description of the prototype models

For the sake of brevity, conventional electronic devices, their manufacture, MEMS technologies, and other functional aspects of systems (and components of individual operating elements of systems) are not described in detail herein. Furthermore, in order to be shorter, in this documentation the invention will be described as pertaining to micro and electronic actuation relays whose use is intended for electrical or electronic systems. It should be noted that many different production techniques can be used to manufacture the relays described in this document, and that the techniques detailed in 61 can also be used for mechanical or optical relays, as well as for

ES 2 249 409 T3 other switching devices. In addition, these techniques can also be useful in electrical and optical systems, consumer electronics, industrial electronics, wireless systems, space applications and other types of applications. Furthermore, it should be understood that the attached spatial descriptions are for illustrative purposes only and that actual latching relays in practice can be spatially arranged in any other orientation or mode. The relay distribution can also be effected by the proper connection and suitable devices of the above relays. Latching relay

Figures 1A and 1B show, respectively, the side view and the top view of a latching relay. With reference to these Figures 1A and 1B, a prototype latching relay 100 suitably comprises a magnet 102, a substrate 104, an insulating coating 106 that protects a conductor 114, a contact terminal 108 and a console 112 placed on top of the substrate by means of a substrate stage 110.

The magnet 102 can be any type of magnet, such as a permanent magnet, an electromagnet or any other type of magnet capable of generating a magnetic field H₀ 134, as described in more detail below. In a prototype model, magnet 102 corresponds to magnet model # 59P09213T001, available from Dexter Magnetic Technologies Corporation of Freemont, California, although, of course, any other type of magnet can also be used. The magnetic field 134 can be generated in various ways and using different magnitudes, from 80 ampere-turns / meter (A / m) to 800 kA / m (from 1 Oersted to 10⁴Oersted) or more. In the prototype model shown in Figure 1, the echo field H₀ 134 can be generated parallel to the Z axis and with a magnitude of the order of about 29.6 kA / m (370 Oersted), although in other models, variations in orientations and magnitudes are used for the magnetic field 134. In various models, a single magnet 102 can be used in conjunction with a number of relays 100 that share a common substrate 104.

Substrate 104 is formed of any type of material that is suitable to act as a substrate, such as silicone, gallium arsenide, glass, plastic, metal, or any other suitable substrate material. In various models, the substrate 104 can be coated with insulating material (such as an oxide) and can be polished flat or just flattened. In various models, several latching relays 100 can share the same substrate 104. Optionally, other devices (such as transistors, diodes, or other electronic devices) may be placed on substrate 104 along with one or more relays 100 using, for example, conventional integral circuit manufacturing techniques. Optionally, a magnet 102 can be used as the substrate and the additional components specified below can be placed directly on the magnet 102. A separate substrate 104 will not be required in such models.

The insulation substrate 106 is made of any material, such as an oxide or any other type of insulation. In a prototype model, the insulation substrate is formed by Probimide 7510. The insulation substrate 106 adequately protects the conductor 114. In Figures 1A and 1B the conductor 114 is shown as a single conductor provided with two ends 126 and 128 arranged in coil shape. Optional forms of conductor pattern 114 employ single or multiple conductor segments and appropriately arranged meandering, serpentine, randomly, or otherwise. Conductor 114 is made of a material capable of conducting electricity, such as gold, silver, copper, aluminum, or any other similar metal. When conductor 114 carries electricity, a magnetic field is generated around conductor 114, as will be described in more detail below.

The console 112 consists of a frame, extension, outcropping or element provided with sufficient capacity to be affected by a magnetic force. In the model shown in Figure 1A, the console 112 includes a magnetic substrate 118 and a conductive substrate 120. The magnetic substrate 118 can be formed of permalloy (such as a NiFe alloy) or any other material that is magnetically sensitive. Conductive substrate 120 can be comprised of gold, silver, copper, aluminum, and any other conductive metal or material. In various models, the console 112 is shown in two states that correspond to whether the relay 100 is "open" or "closed", as described in more detail below. In many models, relay 100 is considered "closed" when a conductive substrate 120 connects stage substrate 110 to contact 108. Conversely, the relay is considered "open" when the console 112 lacks electrical contact with the contact 108. Because the console 112 can be physically detached in and out of the contact 108, various models of the console 112 can be made more flexible. so that said console can be bent in a convenient way. Flexibility can be achieved by varying the thickness of the console (or its different layers of components), by drawing, or by making holes or cuts in the console, and also by using more flexible materials. Optionally, the console 112 can be converted into an articulated device, such as the one described below in Figure 3. Although, of course, the dimensions of the console 112 may vary greatly from one implementation to another, a prototype console 112 suitable for use with a micro-magnetic relay 100 may have a length on the order of 10-1,000 microns, a thickness of 140 microns and 2-600 microns wide. For example, a prototype console conforming to the model shown in Figure 1 may have dimensions of about 600 x 10 x 50 microns, or 1,000 x 600 x 25 microns, or any other convenient dimension.

Contact 108 and stage substrate 110 are located on insulating substrate 106. In various models, stage substrate 110 supports console 112 on top of insulating substrate 106, creating a recess 116 in which to practice empty or fill with air or other gas, or with some liquid such as oil. Although the dimensions of the recess 116 vary widely between different implementations, a prototype recess 116 will have dimensions between 1-100 microns, for example, about 20 microns. Contact 108 can receive console 112 when relay 100 is in the closed state, as described below. Contact 108 and stage substrate 110 can be formed of any conductive material, such as gold, gold alloys, silver, copper, aluminum, or any other similar metal. On

ES 2 249 409 T3 various models, the contact 108 and the stage substrate 110 are formed of similar conductive materials, and the relay is considered "closed" when the console 112 has completed the circuit between the stage substrate 110 and the contact 108 In other models, different formulations are used for the contact 108 and the stage substrate 110, such as those detailed below, relative to Figures 3 and 4. In some models where the console 112 does not conduct electricity, the stage substrate 110 may be formed of a material that is not conductive, such as Probimide, oxide, or any other material. Also, alternate models may not require a stage substrate 110 if the console 112 is supported on the insulating substrate 106.

Principles of operation

According to a general representation of the invention, the magnet 102 generates a magnetic field H₀ 134 that produces a magnetization (m) in the console 112. The magnetization opportunely creates a pair in the console 112 that forces said console 112 to approach or move away from the contact 108, according to the direction of the nuance and thus places the relay 100 in open or closed state. The direction of the magnetization of the console 112 can be adjusted by a second magnetic field opportunely generated by the lead 114, as described in greater detail below.

Continuing with Figures 1A and 1B, the magnetic field H₀ 134 can be applied by a magnet 102 initially in a direction parallel to the Z axis, so that the field is perpendicular to the initial dimensions (for example, to the length) of the console 112. The magnetic field 134 opportunely produces a magnetization in the console 112, which can be composed of a soft magnetic material. Due to the geometry of the console 112, the magnetization of this console 112 is appropriately aligned along the longest axis of the console, which corresponds to the length of the console 112 (parallel to the X axis) of Figure 1.

The orientation of the magnetization of the console 112 depends in turn on the angle (alpha) between the applied magnetic field 134 and the long axis of the console 112. Specifically, when the angle (alpha) is less than 90 degrees, the magnetic moment (m) of console 112 points from end 130 of console 112 towards end 132. Interaction between magnetic moment and magnetic field H₀ 134 thus creates a counterclockwise torque on axis 130 of console 112 that properly moves end 132 upward, thereby opening the circuit between stage substrate 110 and contact 108. Conversely, when the angle (alpha) is greater than 90 degrees, the magnetic moment (m) of the console 112 points from end 132 toward end 130, thus creating a torque in the same clockwise direction in the end 130. The clockwise torque moves end 132 downward to complete the circuit between stage substrate 110 and contact 108. Due to the magnetization (m) of the console. 112 does not change unless the angle (alpha) between the long axis of the console 112 and the applied magnetic field 134 changes, the applied torque will be maintained until an external disturbance occurs. An elastic torque of the console or a shutter (such as the contact) balances the applied magnetic torque and the relay 100 thus offers two stable states corresponding to the positions above and below the console 112 (and consequently to the open and closed states, respectively, of relay 100).

Switching is achieved by a suitable switching technique. In a prototype model, switching is achieved when a second magnetic field is generated that has a component along the long axis of the console 112 that is powerful enough to affect the magnetization (m) of the console 112. In the model shown in figure 1, the main component of the second magnetic field is the component of the field along the X axis. Because the strength of the second magnetic field along the long axis of console 112 is of primary concern, the total magnitude of the second magnetic field is significantly less than the magnitude of magnetic field 134 (although, of course, they can be employed fields of any power in the different models). A second prototype magnetic field can measure on the order of 1.6 kA / m (20 Oersted), although, of course, stronger or weaker fields can be used in other models.

The second magnetic field can be generated, for example, by a magnet of the electronically controlled electromagnet type. Optionally, the second magnetic field can be generated by circulating current through conductor 114. As current flows through conductor 114, a magnetic field is produced in accordance with the "right hand" rule. For example, the current that occurs between point 126 and point 128 of conductor 114 (Figure 1B) generates a magnetic field "within" the center of the coil as shown, and that corresponds to the arrows in field 122 of the figure 1A. Conversely, the current flowing from point 128 to point 126 in Figure 1 generates a magnetic field that flows “out” of the center of the coil shown, and that corresponds to the dashed arrows in the field 124 of FIG. 1A The magnetic field can be looped around conductor 114, in the manner also shown in FIG. 1A, by applying a horizontal component (X) of the magnetic field to console 112.

When the direction of the current or electrical impulses flowing in conductor 114 is varied, the direction of the second magnetic field can be altered at will. By modifying the direction of the second magnetic field, the. magnetization of console 112 may be affected and relay 100 may be appropriately switched open or closed. When the second magnetic field follows the direction of the field arrows 122, for example, the magnetization of the console 112 points toward the end 130. This magnetization creates a torque that follows the clockwise direction at the end 130 and that it places the console 112 in the "down" state, opportunely closing the relay 100. Conversely, when the second magnetic field follows the direction of the dotted field arrows 124, the magnetization of the console 112 points toward the end 132, and a counterclockwise torque is produced that places the console 112 in an "up" state which opportunely opens relay 100. Accordingly, the "up" or "down" state of the console 112 (and therefore the "open" and "closed" state of the relay 100) can be adjusted by controlling the current flowing through

ES 2 249 409 T3 through conductor 114. In addition, because the magnetization of the console 112 remains constant without receiving external alterations, the second magnetic field can be applied in "pulses", or intermittently, as required, to effect the switching of the relay. When the relay does not require a state change, power applied to conductor 114 can be removed, thereby creating a bistable latching relay 100 that does not require power consumption in the idle states. This type of relay is very suitable for applications in space, aeronautics, portable electronics and the like. Fabrication of a latching relay

Figure 2 includes several side views that show a prototype technique for the manufacture of a latching relay 100. It is understood that the process detailed here is only illustrative of one of the many techniques that can be used to create a latching relay 100.

A suitable prototype manufacturing process begins with the placement of a substrate 102, which may require an optional insulating layer. As noted above, any substrate material can be used to manufacture latching relay 100, so an insulating layer will not be necessary if, for example, an insulating substrate is used. In those models that include an insulating layer, this can be a layer of silicon dioxide (SiO₂) or any other insulating material whose thickness is 100 nm (1,000 angstroms). The material chosen as the insulating material and the thickness of the layer may vary depending on each type of implementation.

With reference to Figure 2a, conductor 114 is suitably positioned on a substrate 104. Conductor 114 can be obtained using a technique such as deposition (electron beam deposition, for example), evaporation, galvanization, or catalytic deposition of metals, or similar. In various models, conductor 114 is in the shape of a coil similar to that shown in Figure 1. Optionally, conductor 114 is in the shape of a line, serpentine, circumference, meander, random, or other shape. An insulating layer 106 can be rolled up, or in any case applied, to the substrate 104 and to the conductor 114, as shown in FIG. 2B. An insulating layer 106 can be applied, such as a layer of photoresist material, silicon dioxide, Probimide-7510, or any other insulating material capable of electrically insulating the upper devices. In several models, the surface of the insulating material has been planarized (flat polished) using some mechanical-chemical (CMP) technique.

In the insulating layer 106, the terminal contact zones 108 and 110 can be obtained by a technique such as the photolithographic process and chemical etching or the like (Figure 2C). Terminals 108 and 110 can be obtained by depositing one or more layers of conductive material on insulating layer 106 and then texturing the terminals by chemical etching, for example. In a prototype model, the terminals 108 and 110 suitably include a first layer of chromium (in order to improve adhesion to the insulating layer 106) and a second layer of gold, silver, copper, aluminum, or any other conductive metal. Complementary layers of metal can be added to the contacts using electroplating or electroplating methods to improve contact reliability and decrease resistance.

Referring to Figure 2D, the contact terminals 108 and 110 can be covered with a suitable layer of photoresist material, aluminum, copper, or other material, to form the protective layer 202. An opening 206 can be created in the layer of protection 202 over the tabs on the base of the console 112 using photolithographic, etching, or other similar processes. Console 112 can then be obtained by deposition, surface erosion, or other technique, by depositing one or more layers of material on protective layer 202 and spreading it over opening 206, as shown in FIG. 2E. To improve adhesion, in a prototype model, a base layer 204 of chrome or any other metal can be deposited on the protection layer 202, and one or more conductive layers 120 can also be obtained. Layers 204 and 120 can be obtained, for example, by deposition followed by chemical or mechanical etching. The thickness of layer 120 can be increased by adding another conductive layer (such as gold, gold alloy, etc.), using electroplating or etching methods. The console 112 is also obtained by electrodeposition, or by depositing a layer 118 of permalloy (such as permalloy NiFe) on the conductive layer 120, as shown in FIG. 2F. The thickness of the permalloy 118 layer can be controlled by varying the plate current and the electrodeposition time. Electrodeposition at 0.02 amps per square centimeter over a period of 60 minutes, for example, can produce a prototype permalloy layer thickness of about 20 microns. In various models, an additional layer of permalloy 306 (as shown in Figure 3) can be galvanized on top of the console 112 in order to increase the performance of the console 112 against the magnetic field.

Referring to Figure 2G, the protective layer 202 can be removed by, for example, wet or dry separation (like oxygen plasma) to thereby produce an opening 116 between the console 112 and the insulating layer 106. In various models , to obtain the relay 100 (FIG. 2H), the adhesion layer 204 can be perfectly removed by micro-mechanical etching or other technique. Relay 100 can then be cut and packaged with magnet 102 (as shown in FIG. 1), or it can be processed in a suitable way. It is understood that the permanent magnet 102 can also be prepared directly on the substrate, placed on top of the console, or the coil and console can be prepared directly on a permanent magnetic substrate.

Optional latching relay models

Figures 3 and 4 show optional models of a latching relay 100. Figures 3A and 3B show the side view and the top view, respectively, of an optional model of a latching relay provided with an articulated console 112. The view in The perspective of Figures 3A and 3B has undergone a 90 degree rotation in the XY plane from Figures 1A and 1B, so that the articulated console can be seen in detail. Referring to Figures 3A and 3B, an articulated console 112 suitably includes one or more springs 302 and 304 that support a magnetically responsive element 306 on the insulating layer 106. The element 306 can be quite thick (about 50 microns), in comparison with springs 302 and 304, which can be made of conductive material. As in the 100 relays detailed above5

ES 2 249 409 T3 mind of figure 1, the relays 100 with articulated consoles can be responsive to magnetic fields, such as those generated by the magnet 102 and the conductor 114. In various models, when the relay is in the "closed state ", One or both springs 302 and 304 are in contact with contact terminal 108. Of course, an indeterminate number of springs can be employed. For example, a single spring could be mounted anywhere on element 306. Although springs 302 and 304 located near the center of element 306 are shown in figure 3, the springs can also be arranged near the end of element 306 in the direction of contact 108, in order to increase the torque produced by magnet 102, for example.

Figure 3C consists of the perspective view of a prototype console 112 suitable for joint use with the models shown in Figures 3A and 3B. Console 112 includes an element 306 coupled to conductive layer 120. Holes 310 and / or 312 can be drilled in conductive layer 120 to enhance flexibility of console 112, and optional stud contacts 308 can be mounted on the surface of conductive layer 120 to allow contact with contact terminal 108. Springs 302 and 304 (not shown in Figure 3C) can be attached or installed anywhere on console 112 (such as in the center of conductive layer 120 or at each end of conductive layer 120, as appropriate. ). Optionally, the springs may be comprised of non-conductive material and the console 112 may provide a conductive path between two separate conductors in simultaneous contact with the console in a closed state, as detailed below.

Figures 4A and 4B consist of side views and top views, respectively, of an optional model of a recé hooker 100. As shown in the figure, various models of the console 112 may not directly conduct electricity from the stage layer 110 to the contact 108. In these models, a conductive element 402 may be incorporated into console 112 to provide proper electrical contact between contacts 108 and 408 when relay 100 is in the "closed" state. Figures 4C and 4D consist of perspective views of an optional prototype model of the console 112. In such models, the console 112 may include a magnetically sensitive section 118 separated from the conductive section 402 by an insulating layer 410, which may consist of a dielectric insulator, for example. As noted, stud contacts 308 may also be included in conductive runs 402. When the console 112 is in the state corresponding to the "closed" state of the relay 100, the current will follow the direction indicated by the arrows 412 located between the contact terminals 108 and 408 as appropriate.

Figure 5 consists of the side view of an optional prototype model of relay 100. Referring to Figure 5, a relay 100 may include a magnet 102, a substrate 104, and a console 112 as previously described (for example, in relation to figure 1). Instead of (or in addition to) conductor 114 installed on substrate 104, however, a conductor 114 may be placed on a second substrate 504, as indicated. The second substrate can consist of a substrate of any type, such as plastic, glass, silicone or the like. As in the models described above, conductor 114 can be coated with an insulating layer 506, as appropriate. To prepare a relay 100, the different components must be mounted on the substrates 104 and 504 and the substrates will then be aligned and positioned accordingly. The two substrates 104 and 504 (and the different elements located on them) can be distanced from each other by spacers, such as the spacers 510 and 512 in Figure 5, which can be made of any material.

Continuing with Figure 5, the contact 108 can be mounted on the insulating layer 106, as described above. Optionally, the contact 508 can be mounted on the second substrate 504 of Figure 5 (of course, the console 112 can be retrofitted so that the conductive portion of the console 112 contacts the terminal 508). In other models, both contacts 108 and 508 can be prepared so that the relay 100 is in the initial state when the console 112 is in contact with the terminal 108, in a second state when the console 112 is in contact with the terminal 508, and / or a third state when the console 112 is not in contact with either the terminal 108 or the terminal 508. Of course, to create new models of the roll 100, the general arrangement of the relay 100 shown in Figure 5 can be combined with any of the techniques and arrangements described above.

It goes without saying that other models can be prepared without departing from the scope of the present invention. For example, a two-wire relay can be mounted by incorporating an additional contact 108 that comes into contact with the console 112 when said console is in the open state. Similarly, different topographies and geographies of the relay 100 can be prepared by varying the arrangement of the different elements (such as terminals 108 and 110 and console 112).

The scope of the present invention should be determined by the appended claims and not by the examples given above.