Patent Application
20050057329
1. Field of the Invention
The present invention relates to electromechanical systems. More specifically, the present invention relates to the assembly of electro-mechanical systems by lamination of layers to form magnetic latching switches, and the like.
2. Background Art
Switches are typically electrically controlled two-state devices that open and close contacts to effect operation of devices in an electrical or optical circuit. Relays, for example, typically function as switches that activate or de-activate portions of electrical, optical or other devices. Relays are commonly used in many applications including telecommunications, radio frequency (RF) communications, portable electronics, consumer and industrial electronics, aerospace, and other systems. More recently, optical switches (also referred to as “optical relays” or simply “relays” herein) have been used to switch optical signals (such as those in optical communication systems) from one path to another.
Although the earliest relays were mechanical or solid-state devices, recent developments in micro-electro-mechanical systems (MEMS) technologies and microelectronics manufacturing have made micro-electrostatic and micro-magnetic relays possible. Such micro-magnetic relays typically include an electromagnet that energizes an armature to make or break an electrical contact. When the magnet is de-energized, a spring or other mechanical force typically restores the armature to a quiescent position. Such relays typically exhibit a number of marked disadvantages, however, in that they generally exhibit only a single stable output (i.e., the quiescent state) and they are not latching (i.e., they do not retain a constant output as power is removed from the relay). Moreover, the spring required by conventional micro-magnetic relays may degrade or break over time.
Non-latching micro-magnetic relays are known. The relay includes a permanent magnet and an electromagnet for generating a magnetic field that intermittently opposes the field generated by the permanent magnet. The relay must consume power in the electromagnet to maintain at least one of the output states. Moreover, the power required to generate the opposing field would be significant, thus making the relay less desirable for use in space, portable electronics, and other applications that demand low power consumption.
The basic elements of a latching micro-magnetic switch include a permanent magnet, a substrate, a coil, and a cantilever at least partially made of soft magnetic materials. In its optimal configuration, the permanent magnet produces a static magnetic field that is relatively perpendicular to the horizontal plane of the cantilever. However, the magnetic field lines produced by a permanent magnet with a typical regular shape (disk, square, etc.) are not necessarily perpendicular to a plane, especially at the edge of the magnet. Then, any horizontal component of the magnetic field due to the permanent magnet can either eliminate one of the bistable states, or greatly increase the current that is needed to switch the cantilever from one state to the other. Careful alignment of the permanent magnet relative to the cantilever so as to locate the cantilever in the right spot of the permanent magnet field (usually near the center) will permit bi-stability and minimize switching current. Nevertheless, high-volume production of the switch can become difficult and costly if the alignment error tolerance is small.
What is desired are electromechanical devices, including latching micro-magnetic switches, that are reliable, simple in design, low-cost and easy to manufacture. Hence, what is further desired is improved methods and systems for manufacturing electromechanical devices.
Methods and systems for assembling and making laminated electro-mechanical systems (LEMS), structures, and devices are described herein. In a first aspect, a system and method of assembling an electromechanical structure is provided. A stack of structural layers is aligned. The stack includes at least one structural layer having a movable element formed therein. Each structural layer of the stack is attached to an adjacent structural layer of the stack.
Numerous types of structural layers may be positioned in the stack. In an aspect, a structural layer that includes a permanent magnet is positioned in the stack. In another aspect, a structural layer that includes a high permeability magnetic material is positioned in the stack. In another aspect, a structural layer that includes at least a portion of an electromagnet is positioned in the stack. In another aspect, a structural layer that includes at least one electrical contact area formed thereon is positioned in the stack. Further structural layer types may be positioned in the stack.
The movable element can be a micro-machined movable element. In a further aspect, a first structural layer that includes the micro-machined movable element is positioned in the stack.
In a further aspect, a cavity may be formed in the stack by positioning the structural layer having the movable element between a second structural layer having an opening therethrough and a third structural layer having an opening therethrough. The cavity may be formed such that the movable element is capable of moving in the cavity during operation of the movable element.
In a still further aspect, the plurality of structural layers are formed.
In another aspect, one or more laminated electromechanical structures are assembled or made according to the methods and systems described herein. These structures form devices that can be vertically stacked upon one another and/or laterally spaced apart. In either case, the devices can be electrically and/or optically coupled to form a circuit. Alternatively, they can be coupled (electrically and/or optically) to other discrete or integrated circuits.
In another aspect of the present invention, a latching switch having two or more flexible contact members is assembled using LEMS techniques. A plurality of layers are attached together in a stack. A layer having a first flexible member is positioned/inserted into the stack. A layer having a second flexible member is positioned/inserted into the stack. During operation of the switch, the first flexible member can contact the second flexible member. For example, during contact, an electrical connection can be made between the first and second flexible members.
Furthermore, when the first flexible member moves into contact with the second flexible member, the second flexible member flexes in response. The flex response of the second flexible member provides many benefits for the switch, including reduced contact bounce, reduced settling time, increased lifetime and reliability, among other benefits.
In a further aspect, the layer having the second flexible member includes a third flexible member. During operation of the switch, the first flexible member can contact both the second and third flexible members simultaneously. For example, an electrical connection can be made between the second and third flexible members through the first flexible member. When the first flexible member moves into contact with them, the second and third flexible members both flex in response.
The switch may be actuated in various ways. In an example magnetic actuation aspect of the present invention, the first flexible member has a magnetic material and a longitudinal axis. A permanent magnet layer that produces a first magnetic field is positioned/inserted into the stack. The first magnetic field induces a magnetization in the magnetic material. The magnetization is characterized by a magnetization vector pointing in a direction along the longitudinal axis of the first flexible member. The first magnetic field is approximately perpendicular to the longitudinal axis. A layer that includes a coil is inserted into the stack. The coil is capable of producing a second magnetic field. The second magnetic field causes the first flexible member to switch between a first stable state and a second stable state. In first stable state, the first flexible member is in contact with the second flexible member, which flexes in response. In the second stable state, the first flexible member is not in contact with the second flexible member.
These and other objects, advantages and features will become readily apparent in view of the following detailed description of the invention.
The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.
The present invention will now be described with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. Additionally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears.
It should be appreciated that the particular implementations shown and described herein are examples of the invention and are not intended to otherwise limit the scope of the present invention in any way. Indeed, for the sake of brevity, conventional electronics, manufacturing, laminated electro-mechanical and MEMS technologies and other functional aspects of the systems (and components of the individual operating components of the systems) may not be described in detail herein. Furthermore, for purposes of brevity, the invention is frequently described herein as pertaining to a micro-electronically-machined relay for use in electrical or electronic systems. It should be appreciated that the manufacturing techniques described herein could be used to create mechanical relays, optical relays, any other switching device, and other component types. Further, the techniques would be suitable for application in electrical systems, optical systems, consumer electronics, industrial electronics, wireless systems, space applications, or any other application.
The terms, chip, integrated circuit, monolithic device, semiconductor device, and microelectronic device, are often used interchangeably in this field. The present invention is applicable to all the above as they are generally understood in the field.
The terms metal line, transmission line, interconnect line, trace, wire, conductor, signal path and signaling medium are all related. The related terms listed above, are generally interchangeable, and appear in order from specific to general. In this field, metal lines are sometimes referred to as traces, wires, lines, interconnect or simply metal. Metal lines, generally aluminum (Al), copper (Cu) or an alloy of Al and Cu, are conductors that provide signal paths for coupling or interconnecting, electrical circuitry. Conductors other than metal are available in microelectronic devices. Materials such as doped polysilicon, doped single-crystal silicon (often referred to simply as diffusion, regardless of whether such doping is achieved by thermal diffusion or ion implantation), titanium (Ti), molybdenum (Mo), and refractory metal suicides are examples of other conductors.
The terms contact and via, both refer to structures for electrical connection of conductors from different interconnect levels. These terms are sometimes used in the art to describe both an opening in an insulator in which the structure will be completed, and the completed structure itself. For purposes of this disclosure contact and via refer to the completed structure.
The term vertical, as used herein, means substantially orthogonal to the surface of a substrate. Moreover, it should be understood that the spatial descriptions (e.g., “above”, “below”, “up”, “down”, “top”, “bottom”, etc.) made herein are for purposes of illustration only, and that practical latching relays can be spatially arranged in any orientation or manner.
The above-described micro-magnetic latching switch is further described in international patent publications WO0157899 (titled Electronically Switching Latching Micro-magnetic Relay And Method of Operating Same), and WO0184211 (titled Electronically Micro-magnetic latching switches and Method of Operating Same), to Shen et al. These patent publications provide a thorough background on micro-magnetic latching switches and are incorporated herein by reference in their entirety. Moreover, the details of the switches disclosed in WO0157899 and WO0184211 are applicable to implement the switch embodiments of the present invention as described below.
Laminated Electro-Mechanical Systems
The present invention relates to laminated electromechanical systems (LEMS) and structures. In the laminated electromechanical systems and structures of the present invention, various layers of materials with predefined patterns are formed. The layers are aligned relative to each other, and laminated together or built-up, to form a multilayer structure or stack. Movable mechanical elements can be created in one or more layers of the stack. A movable element is provided with space to move in the stack by creating a cavity in the stack. To create a cavity, layers with openings are aligned on one or both sides of the layer having the movable element. The movable elements are allowed to move freely in the formed cavity after lamination together of the various layers.
Typically, the layers are substantially planar in shape. However, in some embodiments, various layers may have features that do extend out of the plane of the layer.
The present invention may include any type of actuation mechanism to control movement of the movable mechanical elements. Example applicable actuation mechanisms include electrical, electrostatic, magnetic, thermal, and piezoelectric actuation mechanisms. Note that for illustrative purposes, a micro-mechanical latching switch having a magnetic actuation mechanism is described herein as being made as a laminated electromechanical system or structure. It is to be understood from the teachings herein that switches having other actuation mechanisms can also be made as a laminated electro-mechanical system or structure.
The laminated electromechanical systems and structures of the present invention provide numerous advantages. An advantage of the present invention includes low cost. The material(s) used for the layers of the present invention are conventional materials that are relatively inexpensive. Conventional techniques may be used to form patterns in the layers, including screen-printing, etching (e.g., photolithography or chemical), ink jet printing, and other techniques. Furthermore, conventional lamination techniques can be used to attach the layers together.
Another advantage of the present invention is that it is relatively easy to produce. The layers of the present invention are formed. The layers are then merely aligned and attached to each other. Complicated attachment mechanisms are not required. As described above, conventional techniques may be used to attach the layers. Furthermore, laminated electromechanical systems and structures may be made in large sheets that include large numbers of the devices to provide economies of scale.
Another advantage of the present invention is an ease in integration of laminated electromechanical systems and structures with other electronic components (e.g., inductors, capacitors, resistors, antenna patterns, filters). The other electronic components may be formed on one or more of the layers when they are preformed, prior to placement in the stack, for example.
Still another advantage of the present invention is an ease in scaling up or down the dimensions of the laminated electromechanical systems and structures to better handle different levels of power. The laminated electro-mechanical systems and structures may be scaled down to the level of micro-machined structures and devices, for example. Such micro-machined structures and devices require small amounts of power. The laminated electro-mechanical systems and structures may also be scaled up to larger sized structures and devices.
Assembling Laminated Electro-Mechanical Structures According to the Present Invention
Embodiments for making and assembling laminated electro-mechanical systems and structures according to the present invention are described in detail as follows. These implementations are described herein for illustrative purposes, and are not limiting. The laminated electromechanical systems and structures of the present invention, as described in this section, can be assembled in alternative ways, as would be apparent to persons skilled in the relevant art(s) from the teachings herein.
As shown in
To fabricate the latching switch shown in
The structural layers can be formed from a variety of materials. For example, in an embodiment, the structural layers can be formed from thin films that are capable of at least some flexing, and have large surface areas. Alternatively, structural layers can be formed from other materials. The structural layers can be electrically conductive or non-conductive. For example, the structural layers can be formed from inorganic or organic substrate materials, including plastics, glass, polymers, dielectric materials, etc. Example organic substrate materials include “BT,” which includes a resin called bis-maleimide triazine, “FR-4,” which is a fire-retardant epoxy resin-glass cloth laminate material, and/or other materials. In electrically conductive structural layer embodiments, structural layers can be formed from a metal or combination of metals/alloy, or from other electrically conductive materials.
As shown in
As shown in
One or more vias may be formed in structural layers to allow electrical contact between elements in system 100 and elements exterior to system 100. As shown in
Note that although a single latching switch is shown in the embodiment of
Note that various electronic devices or components, including switches, inductors, capacitors, resistors, antenna patterns, and others, can also be fabricated similarly to the processes described herein. For example,
Furthermore, various electronic devices or components, including switches, inductors, capacitors, resistors, antenna patterns, and others may be integrated with embodiments of the present invention. For example,
Transmission lines, such as radio frequency transmission lines, can be accommodated in a laminated electromechanical system of the present invention. For example, in an embodiment, a radio frequency (RF) switch formed in a laminated electromechanical system of the present invention can be coupled to a radio frequency transmission line having a pair of conductive lines or traces. In one embodiment, the conductive lines or traces of the radio frequency transmission line can be formed in parallel on a single structural layer of a stack. In another embodiment, a first conductive line or trace of the radio frequency transmission line can be formed on a first structural layer of a stack, while a second conductive line or trace of the radio frequency transmission line can be formed on a second structural layer of the stack. An insulating or electrically non-conducting structural layer can be positioned in the stack between the first and second conductive lines or traces.
Note that contact areas for movable elements in laminated electro-mechanical systems 100, 300, and 400 may be positioned in various locations. For example
Note that coil 2 can be formed on both the top and bottom sides of cantilever body 52. Furthermore, solenoid coils can be fabricated by connecting coil lines on two layers. As shown in
Furthermore, a movable element can be formed that is capable of movement in the plane of the structural layer in which it is formed. In other words, the movable element may be formed to have a degree of freedom that is coplanar with the plane of the structural layer in which it resides, as opposed to the movable element shown in
For example,
In an embodiment, structural layers can be configured in a stack of a laminated electromechanical system to provide for hermetic sealing of elements of a portion or all of the stack. For example, in an embodiment, it may be desired to hermetically seal a moveable element and related contact(s) within a stack 116, such as those of cantilever assembly 5 shown in
Note that multiple laminated electromechanical devices may be made or assembled according to the present invention in a vertically spaced or stacked configuration, or in a laterally spaced or co-planar configuration. For example,
As described herein, numerous electrical and mechanical device types may be made according to the laminated electromechanical systems and structures of the present invention. These devices can be made in a wide range of sizes, including small-scale micro-mechanical devices and larger scale devices. These devices can also be made to include movable elements, such as latching switches. The following sections are provided to detail structure and operation of an example micro-mechanical latching switch that may be formed according to the laminated electromechanical systems and structures of the present invention. However, note that this description is provided for illustrative purposes, and the present invention is not limited to the embodiments shown therein. As described above, the present invention is applicable to numerous device types.
For example, described further below are laminated electromechanical system embodiments for relays having multiple flexible/moveable contacts.
Overview of a Latching Switch
Magnet 902 is any type of magnet such as a permanent magnet, an electromagnet, or any other type of magnet capable of generating a magnetic field H0 934, as described more fully below. By way of example and not limitation, the magnet 902 can be a model 59-P09213T001 magnet available from the Dexter Magnetic Technologies corporation of Fremont, Calif., although of course other types of magnets could be used. Magnetic field 934 can be generated in any manner and with any magnitude, such as from about 1 Oersted to 104 Oersted or more. The strength of the field depends on the force required to hold the cantilever in a given state, and thus is implementation dependent. In the exemplary embodiment shown in
Substrate 904 is formed of any type of substrate material such as silicon, gallium arsenide, glass, plastic, metal or any other substrate material. In various embodiments, substrate 904 can be coated with an insulating material (such as an oxide) and planarized or otherwise made flat. In various embodiments, a number of latching relays 900 can share a single substrate 904. Alternatively, other devices (such as transistors, diodes, or other electronic devices) could be formed upon substrate 904 along with one or more relays 900 using, for example, conventional integrated circuit manufacturing techniques. Alternatively, magnet 902 could be used as a substrate and the additional components discussed below could be formed directly on magnet 902. In such embodiments, a separate substrate 904 may not be required.
Insulating layer 906 is formed of any material such as oxide or another insulator such as a thin-film insulator. In an exemplary embodiment, insulating layer is formed of Probimide 7510 material. Insulating layer 906 suitably houses conductor 914. Conductor 914 is shown in
Cantilever (moveable element) 912 is any armature, extension, outcropping or member that is capable of being affected by magnetic force. In the embodiment shown in
Alternatively, cantilever 912 can be made into a “hinged” arrangement. Although of course the dimensions of cantilever 912 can vary dramatically from implementation to implementation, an exemplary cantilever 912 suitable for use in a micro-magnetic relay 900 can be on the order of 10-1000 microns in length, 1-40 microns in thickness, and 2-600 microns in width. For example, an exemplary cantilever in accordance with the embodiment shown in
Contact 908 and staging layer 910 are placed on insulating layer 906, as appropriate. In various embodiments, staging layer 910 supports cantilever 912 above insulating layer 906, creating a gap 916 that can be vacuum or can become filled with air or another gas or liquid such as oil. Although the size of gap 916 varies widely with different implementations, an exemplary gap 916 can be on the order of 1-100 microns, such as about 20 microns, Contact 908 can receive cantilever 912 when relay 900 is in a closed state, as described below. Contact 908 and staging layer 910 can be formed of any conducting material such as gold, gold alloy, silver, copper, aluminum, metal or the like. In various embodiments, contact 908 and staging layer 910 are formed of similar conducting materials, and the relay is considered to be “closed” when cantilever 912 completes a circuit between staging layer 910 and contact 908. In certain embodiments wherein cantilever 912 does not conduct electricity, staging layer 910 can be formulated of non-conducting material such as Probimide material, oxide, or any other material. Additionally, alternate embodiments may not require staging layer 910 if cantilever 912 is otherwise supported above insulating layer 906.
Principle of Operation of a Latching Switch
When it is in the “down” position, the cantilever makes electrical contact with the bottom conductor, and the switch is “on” (also called the “closed” state). When the contact end is “up”, the switch is “off” (also called the “open” state). These two stable states produce the switching function by the moveable cantilever element. The permanent magnet holds the cantilever in either the “up” or the “down” position after switching, making the device a latching relay. A current is passed through the coil (e.g., the coil is energized) only during a brief (temporary) period of time to transition between the two states.
(i) Method to Produce Bi-Stability
The principle by which bi-stability is produced is illustrated with reference to
(ii) Electrical Switching
If the bi-directional magnetization along the easy axis of the cantilever arising from H0 can be momentarily reversed by applying a second magnetic field to overcome the influence of (H0), then it is possible to achieve a switchable latching relay. This scenario is realized by situating a planar coil under or over the cantilever to produce the required temporary switching field. The planar coil geometry was chosen because it is relatively simple to fabricate, though other structures (such as a wrap-around, three dimensional type) are also possible. The magnetic field (Hcoil) lines generated by a short current pulse loop around the coil. It is mainly the ξ-component (along the cantilever, see
The operation principle can be summarized as follows: A permalloy cantilever in a uniform (in practice, the field can be just approximately uniform) magnetic field can have a clockwise or a counterclockwise torque depending on the angle between its long axis (easy axis, L) and the field. Two bi-stable states are possible when other forces can balance die torque. A coil can generate a momentary magnetic field to switch the orientation of magnetization (vector m) along the cantilever and thus switch the cantilever between the two states.
Relaxed Alignment of Magnets
To address the issue of relaxing the magnet alignment requirement, the inventors have developed a technique to create perpendicular magnetic fields in a relatively large region around the cantilever. The invention is based on the fact that the magnetic field lines in a low permeability media (e.g., air) are basically perpendicular to the surface of a very high permeability material (e.g., materials that are easily magnetized, such as permalloy). When the cantilever is placed in proximity to such a surface and the cantilever's horizontal plane is parallel to the surface of the high permeability material, the above stated objectives can be at least partially achieved. The generic scheme is described below, followed by illustrative embodiments of the invention.
The boundary conditions for the magnetic flux density (B) and magnetic field (H) follow the following relationships:
B2·n=B1·n, B2×n=(μ2/μ1)B1×n
or
H2·n=(μ1/μ2)H1·n, H2×n=H1×n
If μ1>>μ2, the normal component of H2 is much larger than the normal component of H1, as shown in
This property, where the magnetic field is normal to the boundary surface of a high-permeability material, and the placement of the cantilever (i.e., soft magnetic) with its horizontal plane parallel to the surface of the high-permeability material, can be used in many different configurations to relax the permanent magnet alignment requirement.
Embodiments for Laminated Relays with Multiple Movable Contacts
Described in this section are laminated electromechanical system (LEMS) embodiments for relays having multiple moveable/flexible contacts. Having multiple moveable/flexible contact members (i.e., cantilevers, contacts) provides many benefits, including in reducing undesired “bounce” when a cantilever comes into contact with another element. For example, bounce can occur due to an impact when a first contact initially touches a second contact. The first contact and/or second contact may actually bounce back, temporarily losing the connection between them one or more times. Bouncing is not desirable because it increases a settling time for the electrical connection, and reduces lifetime of the participating contacts (e.g., increasing a duration of arcing between the contacts).
Two and three moveable/flexible contact member embodiments are described below, for illustrative purposes. However, embodiments having more than two or three moveable/flexible contact members are also within the scope and spirit of the present invention.
In embodiments of the present invention, because the second contact (and/or additional contacts) is flexible in addition to the first contact being flexible, the impact of the first contact on the second contact is partially absorbed by the second contact. The second contact retracts with a spring-like effect, and moves together with the first contact, thereby reducing bounce, settling time, and improving reliability.
First, second, and third spacer layers 1308, 1312, and 1316 each include an opening therethrough. First, second, and third spacer layers 1308, 1312, and 1316 are similar to first and second spacer layers 106 and 110 described above with respect to
Top cover layer 1306 and bottom cover layer 1318 are structural covers that cover the ends/sides of cavity 1320 within the spacer layers and other layers of switch 1300. For example, in an embodiment, top cover layer 1306 and bottom cover layer 1318 are similar to first substrate layer 104 shown in
In embodiments, top cover layer 1306 and/or bottom cover layer 1318 can include additional features. For example, in embodiments, top cover layer 1306 and/or bottom cover layer 1318 can include: an electromagnet, such as a coil; a magnetic material, such as a soft magnetic material (e.g. permalloy) or a permanent magnet; and electrically conductive features, such as contacts, traces, and/or vias.
In embodiments, various layers of switch 1300, including top cover layer 1306, bottom cover layer 1318, and first, second, and third spacer layers 1308, 1312, and 1316, can be made from a variety of materials. Such materials include a glass material, substrate materials, dielectrics, a plastic, a polymer, an epoxy (e.g., FR4), a metal or combination/alloy of metals (e.g., iron, steel, copper, aluminum, titanium, etc.), or other material, including suitable hermetic sealing materials, mentioned elsewhere herein, or otherwise known.
As shown in
Although first and second flexible members 1302 and 1304 are shown in
According to various actuation mechanisms, either one of, or both of, first flexible member 1302 and second flexible member 1304 can be caused to move (i.e., be moveable) into contact with the other flexible member. Such actuation mechanisms include magnetic, electrostatic, and others. For purposes of illustration, switch 1300 is described below as having first flexible member 1302 being moveable (i.e., the “master”), while second flexible member 1304 is not moveable (i.e., the “slave”). However, it will be understood to persons skilled in the relevant arts(s) that either or both of flexible members 1302 and 1304 could be moveable.
Switch 1300 can switch between first and second stable states due to the selected actuation mechanism.
Note that switch 1300 is described as having the moveable member move downward, for illustrative purposes. However, for the embodiments described herein, it is to be understood that the moveable member could alternatively move upward, sideways, etc., depending on the particular configuration of the moveable/flexible members of a switch.
Layers 1310 and 1314, including first and second flexible members 1302 and 1304, can have electrically conductive features formed thereon (traces, contacts, etc.), to support the electrical connection of signals by switch 1300. For example, in the first stable state, shown in
In the second stable state, such as shown in
As shown in
First flexible member 1302 and second flexible member 1304, and their respective layers 1310 and 1314, can be made from a variety of materials. Such materials include a glass material, substrate materials, dielectrics, a plastic, a polymer, an epoxy (e.g., FR4), a metal or combination/alloy of metals (e.g., iron, steel, copper, aluminum, titanium, etc.), other materials, and combinations thereof. Furthermore, in magnetically actuated embodiments, first flexible member 1302 can include a magnetic material, including a soft magnetic material such as a permalloy.
As described above, various actuation mechanisms can be used for switch 1300. For example,
First, second, and third spacer layers 1408, 1412, and 1416 collectively contribute to forming a cavity 1420 in switch 1400. Cavity 1420 allows first and/or second flexible members 1402 and 1404 to move and/or flex freely to contact each other, and to move away from each other. Top cover layer 1406 and bottom cover layer 1418 are structural covers that cover the ends/sides of cavity 1420 within the spacer layers and other layers of switch 1400.
In the present magnetic actuation embodiment, first flexible member 1402 includes a soft magnetic material, such as a permalloy (similarly to magnetic layer 918 of cantilever 912, described above). Permanent magnet layer 1430 produces a magnetic field 1434, similar to magnetic field H0 934 produced by permanent magnet 902, shown in
Bottom cover layer 1418 includes a conductor, such as coil 1432, which is similar to conductor 914. Coil 1432 is capable of producing a second magnetic field to cause first flexible member 1402 to switch between the first stable state (“on” state, moved in contact with second flexible member 1404) and the second stable state (“off” state, moved away from second flexible member 1404). In the first stable state, first flexible member 1402 is in contact with second flexible member 1404, which flexes in response, similarly to as shown for second flexible member 1304 shown in
Optional soft magnetic layer 1440 (also referred to as a “dipole layer”), when present, is used to relax the permanent magnet alignment requirement, as described above. Soft magnetic layer 1440 can be a permalloy or other soft magnetic material.
Switch 1400 can include a plurality of electrically conductive vias to couple internal signals to other internal signals and/or to externally accessible contacts. For example, an electrically conductive via 1442 couples layer 1414 to an externally accessible contact 1452. Thus, in an embodiment, first flexible member 1402 can be coupled to an external signal present at externally accessible contact 1452 through layer 1414 and electrically conductive via 1442.
Furthermore, an electrically conductive via 1446 couples layer 1410 to an externally accessible contact 1454. Thus, in an embodiment, second flexible member 1404 can be coupled to an external signal present at externally accessible contact 1454 through layer 1410 and electrically conductive via 1446.
Furthermore, as shown in
Second flexible member 1404 can be made from a variety of materials, including a magnetic material (e.g., permalloy) or a non-magnetic material (e.g., a metal such as beryllium copper, or other material). For example, second flexible member 1404 can be made from flexible materials such as a substrate material, polymer, plastic, epoxy, dielectric material, and/or other materials described herein or otherwise known.
Note that the positions in stack 1450 of permanent magnetic layer 1430, coil 1432, and soft magnetic layer 1440 are provided for illustrative purposes, and are not limiting. It will be understood to persons skilled in the relevant art(s) from the teachings herein that permanent magnetic layer 1430, coil 1432, and soft magnetic layer 1440 can each be positioned above or below cavity 1420, in numerous combinations.
Layer 1410 includes a U-shaped portion 1462, a first flexure member 1464, a second flexure member 1466, and first flexible member 1402. U-shaped portion 1462 anchors or supports first flexible member 1402 by being held between layers of stack 1450. In the embodiment of
Note that in an alternative embodiment, U-shaped portion 1462 of layer 1414 can alternatively be a ring shaped portion, which extends substantially, including completely, around first flexible member 1402 in switch 1400, to give greater support to first flexible member 1402. Furthermore, other equivalent configurations are envisioned.
As described above, switches can have more than two moveable/flexible members, in embodiments of the present invention. For example,
Furthermore, an electrically conductive end portion of first flexible member 1502 touches an electrically conductive end portion of second flexible member 1504 and an electrically conductive end portion of third flexible member 1580, forming a closed electrical conduction path between second and third flexible members 1504 and 1580 through first flexible member 1502. Thus, the first stable state shown in
In the second stable state, such as shown in
As shown in
Note that second and third flexible members 1504 and 1580 can be made from magnetic materials (e.g., permalloy) or non-magnetic materials (e.g., a metal such as beryllium copper or other electrically conducting material). For example, second and third flexible members 1504 and 1580 can be made from flexible materials such as a substrate material, polymer, plastic, epoxy, dielectric material, and/or other materials described herein or otherwise known.
As shown in
First, second, and third electrically conductive layers 1732, 1736, and 1742 can be made from any suitable electrically conductive material, such as a metal or combination of metals/alloy, including aluminum, copper, gold, silver, rhodium, tin, etc. These layers can be uniformly made from the electrically conductive material, or contain features (e.g., traces, contacts, etc.) made from the electrically conductive material. These layers can be formed in any manner, including deposition, electro-plating, lamination techniques, etc.
Due to soft magnetic layer 1746, first flexible member 1702 is useful in a magnetically actuated switch embodiment. In such an embodiment, soft magnetic layer 1746 operates as the magnetic material of the cantilever. Further details of a magnetically actuated switch embodiment are described above, for example, with respect to switch 1400 (shown in
Furthermore, in an embodiment, either or both of soft magnetic layer 1746 and electrically conductive layer 1732 can be coupled to a potential, such as a ground potential, to serve as a ground or other potential plane for switch 1700. Thus, the configuration of switch 1700 can provide advantages in providing a better ground (or other potential) connection, reducing noise, switching spikes, etc. In a radio frequency signal embodiment for switch 1700, electrically conductive plane layer 1732 and/or soft magnetic layer 1746 can operate as a line of a RF transmission line, while the path through second and third flexible members 1804 and 1880, and electrically conductive layer 1836, form the other line. Alternatively, other RF transmission lines (e.g., co-planar type, etc.) can be formed on the same electrically conductive layer.
As shown in
Furthermore, electrically conductive layer 1836 of first flexible member 1802 touches an electrically conductive end portion of second flexible member 1804 and an electrically conductive end portion of third flexible member 1880, forming a closed electrical conduction path between second and third flexible members 1804 and 1880 through electrically conductive layer 1836. Thus, the first stable state shown in
In the second stable state, such as shown in
Electrically conductive plane layer 1842 is optionally present. When present, electrically conductive plane layer 1842 can be coupled to a potential, such as a ground potential, to operate as a ground plane or other potential plane for switch 1800. Similarly, soft magnetic layer 1832 can be coupled to a potential, such as a ground potential. Thus, the configuration of switch 1800 can provide advantages in providing a better ground (or other potential) connection, reducing noise, switching spikes, etc. In a radio frequency signal embodiment for switch 1800, electrically conductive plane layer 1842 and/or soft magnetic layer 1832 can operate as one line of a RF transmission line, while the path through second and third flexible members 1804 and 1880, and electrically conductive layer 1836, form the other line. Alternatively, other RF transmission lines (e.g., co-planar type, etc.) can be formed on the same electrically conductive layer.
As shown in
As shown in
Coil 2032 is capable of producing a second magnetic field to cause first flexible member 2002 to switch between the first stable state (“on” state, moved in contact with second flexible member 2004), indicated as position 2002a in
As described above, flexing of second flexible member 2004 thereby reduces bounce, reduces settling time, and improves reliability, for switch 2000.
The embodiments described herein can be varied and combined in any manner. Variations of the above-described embodiments can be formed to construct multi pole, multi throw switches as well as arrays.
Flowchart 2100 begins with step 2102. In step 2102, a layer having a first flexible member formed therein is included into the stack, wherein said first flexible member has a magnetic material and a longitudinal axis. For example, the layer can be layer 1414 shown in
In step 2104, a layer having a second flexible member therein is included into the stack. For example, the layer can be layer 1410 shown in
In step 2106, a permanent magnet layer that produces a first magnetic field is included in the stack. For example, the permanent magnet layer can be permanent magnet layer 1430 shown in
In step 2108, a layer that includes a coil is included into the stack. For example, the layer can be layer 1418 shown in
In embodiments, further steps can include including spacer layers into the stack, including a soft magnetic layer into the stack, including electrically conductive layers into the stack, including dielectric layers into the stack, and/or other steps that are apparent from the description above.
Flowchart 2200 begins with step 2202. In step 2202, a first magnetic field is produced by a permanent magnet, which thereby induces a magnetization in a magnetic material of a first flexible member in a layer of a stack, the magnetization characterized by a magnetization vector pointing in a direction along a longitudinal axis of the first flexible member, the first magnetic field being approximately perpendicular to the longitudinal axis.
For example, in an embodiment, the first magnetic field can be magnetic field 1434 produced by permanent magnet layer 1430, as shown in
In step 2204, a second magnetic field is produced to cause the first flexible member to switch between a first stable state and a second stable state, wherein in the first stable state, the first flexible member is in contact with a second flexible member in a layer of the stack, wherein the second flexible member flexes in response, wherein only temporary application of the second magnetic field is required to change direction of the magnetization vector thereby causing the first flexible member to flex into contact with the second flexible member.
For example, in an embodiment, the second magnetic field is produced by coil 1432, as shown in
While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.
This is a continuation-in-part application of pending U.S. application Ser. No. 10/664,404, filed Sep. 17, 2003 (Atty. Dkt. No. 2040.0410001), which is herein incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10664404 | Sep 2003 | US |
| Child | 10740837 | Dec 2003 | US |
