Enhanced signal amplitude in acoustic-magnetomechanical EAS marker

Systems (100) and methods (600) for making a marker. The methods comprise: obtaining a resonator material which has been annealed under a tensile force selected to provide a maximum resonant amplitude at a bias field Hmax in the marker; and providing with the bias material of the marker an operating bias field Hoperating with a value less than a value of said bias field Hmax. The value of Hoperating is reduced by performing at least one of the following operations: selectively modifying a geometry of a bias material which is to be disposed in a housing of the marker; selectively modifying a spacing between the resonator material and the bias material arranged in a stacked configuration; and partially de-gaussing the bias material subsequent to being fully saturated.

FIELD OF THE INVENTION

This document relates generally to Electronic Article Surveillance (“EAS”) systems. More particularly, this document relates to EAS systems employing an Acoustic-MagnetoMechanical (“AMM”) marker and methods of making such an AMM marker.

BACKGROUND OF THE INVENTION

A typical EAS system in a retail setting may comprise a monitoring system and at least one security tag or marker attached to an article to be protected from unauthorized removal. The monitoring system establishes a surveillance zone in which the presence of security tags and/or markers can be detected. The surveillance zone is usually established at an access point for the controlled area (e.g., adjacent to a retail store entrance and/or exit). If an article enters the surveillance zone with an active security tag and/or marker, then an alarm may be triggered to indicate possible unauthorized removal thereof from the controlled area. In contrast, if an article is authorized for removal from the controlled area, then the security tag and/or marker thereof can be deactivated and/or detached therefrom. Consequently, the article can be carried through the surveillance zone without being detected by the monitoring system and/or without triggering the alarm.

The security tag or marker generally consists of a housing. The housing is made of a low cost plastic material, such as polystyrene. The housing is typically manufactured with a drawn cavity in the form of a rectangle. This type of housing works reasonably well, but suffers from bowing and warping that result from the drawing process introducing stresses into the plastic. In addition, the cavity crushes under stress of application or bending. An improved design was created a few years ago that added fingers or wavy ends to the label. This improvement reduces issues, but does not completely eliminate the crushing and bending issues.

A bias magnet is disposed within the housing adjacent to a magnetoelastic resonator. The bias magnet is made of a semi-hard magnetic material. The resonator is made of a soft magnetic material in the form of an elongate thin ribbon produced by rapid quenching. During operation, the security tag or marker produces a resonate signal with a particular amplitude that is detectable by the monitoring system. The resonator signal's amplitude has been conventionally enhanced by increasing a width of the resonator, whereby the production cost and complexity of the resonator is undesirably increased.

SUMMARY OF THE INVENTION

The present invention concerns implementing systems and methods for making a marker. The marker may include, but is not limited to, an EAS label attachable to an article to be protected from unauthorized removal from a particular area. The methods involve: obtaining a resonator material which has been annealed under a tensile force selected to provide a maximum resonant amplitude at a bias field Hmax; and providing by the bias material in the marker an operating bias field Hoperatingwith a value less than a value of the bias field Hmax. The value of the bias field Hoperatingis reduced by performing at least one of the following operations: selectively modifying a geometry of a bias material which is to be disposed in a housing of the marker; selectively modifying a spacing between the resonator material and the bias material arranged in a stacked configuration; and partially de-gaussing the bias material subsequent to being fully saturated.

In some scenarios, the geometry of the bias material is selectively modified by changing a width and/or a thickness of the bias material which has a generally rectangular shape. The spacing is selectively modified by disposing a spacer between the resonator material and the bias material arranged in the stacked configuration. The bias material is partially de-gaussed through an application of a reverse direct magnetic field to the marker. Notably, a signal amplitude of the marker is increased by an amount equal to or greater than half an original signal amplitude value as a result of reducing the value of the operating bias field Hoperating. Also, a magnetic clamping of the resonator material by the bias material is decreased as a result of reducing the value of the operating bias field Hoperating.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will now be described with respect toFIGS. 1-6. The present invention generally relates to novel systems and methods for making a marker. The marker may include, but is not limited to, an EAS label attachable to an article to be protected from unauthorized removal from a particular area. The methods involve: obtaining a resonator material which has been annealed under a tensile force selected to provide a maximum resonant amplitude at a bias field Hmax; and providing with the bias material of the marker an operating bias field Hoperatingwith a value less than a value of the bias field Hmax. The value of Hoperatingis reduced by performing at least one of the following operations: selectively modifying a geometry of a bias material which is to be disposed in a housing of the marker; selectively modifying a spacing between the resonator material and the bias material arranged in a stacked configuration; and partially de-gaussing the bias material subsequent to being fully saturated.

Notably, the security tags and detachers (or external tools) of the present invention can be used in a variety of applications. For example, the present invention can be used in an EAS system for detecting the unauthorized removal of articles from a particular area or space. EAS systems are well known in the art, and therefore will not be described herein.

EAS System

Referring now toFIGS. 1-6, there is provided schematic illustrations useful for understanding an exemplary EAS system100in accordance with the present invention. The EAS system100comprises a monitoring system106-112,114-118and at least one marker102. The marker102may be attached to an article to be protected from unauthorized removal from a business facility (e.g., a retail store). The monitoring system comprises a transmitter circuit112, a synchronization circuit114, a receiver circuit116and an alarm118.

During operation, the monitoring system106-112,114-118establishes a surveillance zone in which the presence of the marker102can be detected. The surveillance zone is usually established at an access point for the controlled area (e.g., adjacent to a retail store entrance and/or exit). If an article enters the surveillance zone with an active marker102, then an alarm may be triggered to indicate possible unauthorized removal thereof from the controlled area. In contrast, if an article is authorized for removal from the controlled area, then the marker102can be deactivated and/or detached therefrom. Consequently, the article can be carried through the surveillance zone without being detected by the monitoring system and/or without triggering the alarm118.

The operations of the monitoring system will now be described in more detail. The transmitter circuit112is coupled to the antenna106. The antenna106emits Radio Frequency (“RF”) bursts at a predetermined frequency (e.g., 58 KHz) and a repetition rate (e.g., 60 Hz), with a pause between successive bursts. In some scenarios, each RF burst has a duration of about 1.6 ms. The transmitter circuit112is controlled to emit the aforementioned RF bursts by the synchronization circuit114, which also controls the receiver circuit116. The receiver circuit116is coupled to the antenna108. The antenna106,108comprises close-coupled pick up coils of N turns (e.g., 100 turns), where N is any number.

When the marker102resides between the antennas106,108, the RF bursts transmitted from the transmitter112,108cause a signal to be generated by the marker102. In this regard, the marker102comprises a resonator110and a bias element104disposed in a housing126. The RF bursts emitted from the transmitter112,108drive the resonator110to oscillate at a resonant frequency (e.g., 58 KHz). As a result, a signal is produced with an amplitude that decays exponentially over time.

The synchronization circuit114controls activation and deactivation of the receiver circuit116. When the receiver circuit116is activated, it detects signals at the predetermined frequency (e.g., 58 KHz) within first and second detection windows. In the case that an RF burst has a duration of about 1.6 ms, the first detection window will have a duration of about 1.7 ms which begins at approximately 0.4 ms after the end of the RF burst. During the first detection window, the receiver circuit116integrates any signal at the predetermined frequency which is present. In order to produce an integration result in the first detection window which can be readily compared with the integrated signal from the second detection window, the signal emitted by the marker102should have a relatively high amplitude (e.g., greater than or equal to about 1.5 nWb).

After signal detection in the first detection window, the synchronization circuit114deactivates the receiver circuit116, and then re-activates the receiver circuit116during the second detection window which begins at approximately 6 ms after the end of the aforementioned RF burst. During the second detection window, the receiver circuit116again looks for a signal having a suitable amplitude at the predetermined frequency (e.g., 58 kHz). Since it is known that a signal emanating from the marker102will have a decaying amplitude, the receiver circuit116compares the amplitude of any signal detected at the predetermined frequency during the second detection window with the amplitude of the signal detected during the first detection window. If the amplitude differential is consistent with that of an exponentially decaying signal, it is assumed that the signal did, in fact, emanate from a marker between antennas106,108. In this case, the receiver circuit116issues an alarm118.

Resonator and Bias Elements

The amplitude of the marker102is at least partially a result from the materials used to form the resonator110and the bias element104. The resonator110can be formed of any suitable resonator material. An exemplary suitable resonator material is made from Fe, Co and Ni as main elements. Thus, the resonator material can have a chemical composition of FeaCobNicSidBe, wherein a, b, c, d and e are in atomic percent. The values of a-e can respectively fall within the following ranges: 22≦a≦36; 10≦b≦13; 43≦c≦49; 1≦d≦4; and 15≦e≦17. For example, the resonator material may have a chemical composition Fe24Co12Ni46Si2B16. The atomic percentages for Fe, Co and Ni may vary approximately ±5% from the stated values for atomic percent.

The resonator material may be rapidly quenched and annealed prior to assembly of the marker102. The manner in which the resonator material is quenched can be the same as or similar to that disclosed in U.S. Pat. No. 4,142,571 (“the '571 patent”) and U.S. Pat. No. 7,088,246 (“the '246 patent), the disclosures of which are incorporated herein by reference. The manner in which the resonator material is annealed can be the same as or similar to that disclosed in U.S. Pat. No. 6,645,314 (“the '314 patent”), the disclosure of which is incorporated herein by reference.

For example, in some scenarios, the resonator material is annealed (subsequent to rapid quenching) at a temperature between 340° C. and 400° C. for a few seconds (e.g., 5-30 sec.) under a tensile force. The tensile force is used to control the material's amplitude. In turn, the material's amplitude is controlled such that it reaches its maximum value at a bias field HMAX(e.g., 7.7 Oe or 6.5 Oe). To reduce the value of the bias field HMAX, a relatively low tensile force (e.g., 10-20 N) is employed during annealing.

FIG. 2shows bias sweep curves for two samples with the same chemical composition, but annealed with different conditions. As shown inFIG. 2, the bias field value HMAXfor a first sample equals 7.7 Oe (as shown by reference number200) and the anisotropy field Hkis 9 Oe (as shown by reference number206). The bias field value HMAXfor a second sample equals 6.5 Oe (as shown by reference number200) and the anisotropy field Hkis 8 Oe (as shown by reference number208). The reduction of the bias field value HMX for the second sample enables a corresponding marker to operate at a low bias field (e.g., 6.5 Oe), whereby magnetic clamping is relieved. As a result, the maximum resonant amplitude of the signal emitted from the corresponding marker is increased as compared to that of a marker comprising the first sample material (e.g., from about 1.0 nWb to about 1.5 nWb).

The bias field value Hoperatingis further reduced when the marker102is assembled and/or magnetized. To further reduce the bias field value Hoperating, the geometry of the bias element104can be modified and/or the distance between components104,110can be increased. The same purpose is achieved by applying a reverse Direct Magnetic (“DM”) field to partially de-Gauss a fully saturated bias material. Each of the listed techniques for further reducing the bias field value Hoperatingwill be described in detail below.

As shown inFIGS. 1,3and4, the bias element104has a generally rectangular shape. Thus, its geometry can be modified by decreasing its width302and/or its thickness402. In conventional EAS systems, the bias element of a marker has a width of about 6 mm and a thickness of about 48 microns. In contrast, the geometry of the bias element104may be modified such that it has a width302of less than 6 mm (e.g., about 5 mm) and/or a thickness402less than 48 microns (e.g., about 40 microns). Such geometry modifications of the bias element104may result in a decrease of the marker's operating bias field Hoperatingfrom e.g., 6.5 Oe to e.g., 5.5 Oe.

As shown inFIG. 5, the marker102comprises a plurality of material layers defining components104,110,126,502. The resonator110and bias element104reside between two housing126layers. The bias element104is disposed below the resonator110in a stacked arrangement. A spacer502may optionally be provided between the resonator110and bias element104. The spacer502is formed of any suitable material, such as plastic. The thickness of the spacer502is selected to further decrease the marker's operating bias field Hoperatingfrom e.g., 6.5 Oe to e.g., 5.5 Oe. In conventional systems, the spacer has a thickness of 10 mils. In contrast, the spacer502of the present invention can have a thickness greater than 10 mils if it is desirable to obtain a lower operating bias field Hoperating.

As noted above, the operating bias field Hoperatingcan be further reduced through an application of a reverse DM field to a fully saturated bias element. An exemplary method600is shown inFIG. 6that is useful for understanding this feature of the present invention. As shown inFIG. 6, the method600begins with step602and continues with step604. In step604, a marker (e.g., marker102ofFIG. 1) is assembled. Such assembly involves disposing a stack in a housing (e.g., housing126ofFIG. 1). The stack comprises a resonator (e.g., resonator110ofFIG. 1), and an optional spacer (e.g., spacer502ofFIG. 5).

Once the marker has been fully assembled, a magnetic field is applied thereto for purposes of saturating the bias element material, as shown by step606. Techniques for saturating a bias element material are well known in the art, and therefore will not be described herein. Next in step608, a reverse DM field is applied to the marker with the fully saturated bias element material. Techniques for applying a reverse DM field to an object are well known in the art, and any known method can be used herein without limitation. For example, the reverse DM field can be applied using a coil or a magnet in a direction that is the reverse of the direction in which the magnetic field was previously applied to saturate the bias material. Upon completing step608, step610is performed where method600ends or other tasks are performed.

The following Table 1 shows test results of tests performed using the second sample referred to above in relation toFIG. 2to further reduce a bias field strength of a marker in accordance with the various techniques described above.

ConfigurationAm-Fre-BiasplitudequencyWidthSpacer(nWb)(kHz)QNotes5 mm0 mm1.5258.5894056 mm0 mm1.0858.684399Conventional Label Design6 mm0 mm1.5058.11334710 Oe DC de-gaussed6 mm0.19 mm1.4658.276358Paper spacer between bias6 mm0.39 mm1.6258.356392element and resonator
As shown in Table 1, the signal amplitude increases by about 50% (e.g., changes from 1.08 nWb to >1.46 nWb) in other design formats as the operating bias field Hoperatingis reduced. In addition to or alternative to the above described techniques for reducing the operating bias field Hoperating, multiple resonators may be disposed in a marker whereby the signal amplitude is increased.

Marker Housing

The marker is shown inFIG. 1as having a particular housing architecture. Embodiments of the present invention are not limited to the housing architecture shown inFIG. 1. As such, additional alternative housing architectures will now be discussed which can be used with the present invention without limitation.

Notably, each of the additional alternative housing architectures comprise stiffener edge features (e.g., ribs, protrusions and/or dimples) that stiffen the marker considerably from previous marker designs, such as that discussed above in the background section of this paper. The new marker design greatly improves the rigidity of the plastic and significantly improves the label performance both under crush conditions and bending conditions. In addition, the yield in the factory improves because the markers remain flat after forming. Previously, a few percent of the markers were “dead” (non-performing) due to warping in the cavity (e.g., cavity702ofFIG. 7) during manufacturing. Furthermore, the stiffener edge features allow the housing thickness to be reduced as compared to that of conventional marker housings, thereby reducing the manufacturing costs of the markers without having any decreased performance thereof. The stiffener edge features facilitate improved performance of the markers via an increase in their signal's amplitude.

Referring now toFIGS. 7-11, there is provided various schematic illustrations of an exemplary architecture for a top portion700of a marker's housing. More particularly,FIG. 7provides a perspective view of the top portion700. A cross-sectional view of the top portion700is provided inFIG. 8. A top view of the top portion700is provided inFIG. 9. A side view of the top portion700is provided inFIG. 10. A front view of the top portion700is provided inFIG. 11.

Notably, the bottom portion (not shown) of the marker's housing is generally a flat panel which is coupled to the top portion700at least along the entire peripheral edge thereof (e.g., via an adhesive or heat weld). The top and bottom portions of the marker housing are formed of a flexible material, such as plastic (e.g., polystyrene). A single sheet of flexible material can be used to form top portions and/or bottom portions for a number of marker housings (e.g.,20marker housings). With regard to the top portion700, the single sheet of the flexible material is shaped through the application of heat and/or pressure thereto so as to cause the sheet to conform to the shape of a mold. The mold may be designed such that: a number of top portions700are fabricated at the same time from a single sheet of housing material; and various elements of the top portion are formed concurrently with each other (e.g., a cavity and a plurality of stiffener edge features).

As shown inFIG. 7, the top portion700has a generally rectangular shape with a cavity702formed therein. The cavity702is sized and shaped to receive the resonator and bias elements described above. When the top and bottom portions of a marker's housing are coupled together, the resonator and bias elements are said to be housed in the marker's housing.

As also shown inFIG. 7, a bottom wall704of the cavity is flat or planar. In contrast, each of the four sidewalls706-712has a non-planar shape. More particularly, each short sidewall708,712has a generally serpentine shape. Each elongate sidewall706,710has a non-planar shape defined by at least one stiffener edge feature714formed therein (or along an exterior surface726thereof). The stiffener edge features714serve to strengthen the marker housing by increasing the crush resistance and bend resistance of the elongate sidewalls706,710. As such, each stiffener edge feature714extends a certain percentage of the height724of the respective sidewall706-712(e.g., 50-100%). Each stiffener edge feature may be a hollow or solid structure. In addition, the overall thickness of the marker housing is reduced. In effect, the cost associated with fabricating the marker housing is also reduced without any performance degradation of the marker.

In this regard, each stiffener edge feature714comprises a protrusion/rib extending in a direction out and away from the housing material, a dimple extending in a direction out and away from the housing material, or a dimple extending in a direction towards the center of the housing. The stiffener edge features on each elongate sidewall706,710can be of the same or different types. For example, the stiffener edge features of sidewalls706and710can be of the same type as shown inFIG. 7, i.e., convex dimples714extending out and away from the housing material. However, the stiffener edge features of sidewalls706and710can be of two different types although not shown, i.e., convex dimples714extending out and away from the housing material and concave dimple extending in and towards the center of the housing. In all scenarios, each stiffener edge feature714may have a dome shape as shown inFIG. 7, a square shape, a rectangular shape, a triangular shape or any other shape suitable for providing structural strength to the marker housing.

Any number of stiffener edge features714can be provided on each elongate sidewall706,710of the top portion700. For example, eleven stiffener edge features714are provided on each sidewall706and710. The present invention is not limited to the particular numbers of stiffener edge features shown inFIG. 7.

The stiffener edge features on each elongate sidewall706,710can have equal spacing therebetween or non-equal spacing therebetween. For example, the spacing between adjacent stiffener edge features714of each sidewall706,710is the same for all adjacent pairs of edge features thereof. The spacing between the stiffener edge features of each sidewall can be the same as or different than that of the other sidewalls. For example, the stiffener edge features714of sidewall706are spaced apart by a particular distance722(e.g., approx. 0.1 inches). The spacing between the outer most edge features716of each sidewall and the respective sidewall end718can be the same or different for each sidewall.

Referring now toFIGS. 12-14, there are various schematic illustrations of another exemplary architecture for a top portion1200of a marker's housing. More particularly,FIG. 12provides a perspective view of the top portion1200.FIG. 13provides a cross sectional view of the top portion1200.FIG. 14provides a top view of the top portion1200.

Notably, top portion1200is the same as or substantially similar to top portion700with a few exceptions which will be described below. As such, the discussion provided above in relation toFIGS. 7-11is suitable for understanding the general architecture of top portion1200(especially the stiffener edge features formed on the elongate sidewalls thereof).

As shown inFIG. 12, the bottom wall1204of the cavity1202is non-planar as opposed to planar (as shown inFIG. 7). In this regard, the bottom wall1204has a depression1206formed therein. The depression1206can have any shape and/or size selected in accordance with a particular application. For example, the depression1206has a generally rectangular shape, and extends into the cavity1202.

The two elongate sidewalls1208,1216of the depression1206each have stiffener edge features1210formed thereon. Each stiffener edge feature1210comprises a protrusion, ridge or dimple extending in a direction towards the center of the housing (as shown inFIG. 12). The stiffener edge features on each sidewall1208,1216can be of the same or different types. In all scenarios, each stiffener edge feature1210may have a dome shape as shown inFIG. 12, a square shape, a rectangular shape, a triangular shape or any other shape suitable for providing structural strength to the marker housing.

Any number of stiffener edge features1210can be provided on each sidewall1208,1216of the depression1206. The stiffener edge features1210on each sidewall can have equal spacing therebetween or non-equal spacing therebetween. The spacing between the stiffener edge features210of each sidewall1208,1216can be the same as or different than that of the other sidewalls. The spacing between the outer most edge features1212of each sidewall1208,1216and the respective sidewall end1214can be the same or different for each sidewall.

Referring now toFIG. 15, there is provided a schematic illustration of another exemplary architecture for a top portion1500of a marker's housing. Top portion1500is the same as or substantially similar to top portions700,1200with a few exceptions which will be described below. As such, the discussion provided above in relation toFIGS. 7-14is suitable for understanding the general architecture of top portion1500(especially the stiffener edge features formed on the elongate sidewalls thereof).

As shown inFIG. 15, a wall1502of the top portion1500is non-planar as opposed to planar (as shown inFIG. 7). In this regard, the wall1502has a depression1504formed therein. The depression1504can have any shape and/or size selected in accordance with a particular application. For example, the depression1504has a generally rectangular shape, and extends into the cavity (not shown inFIG. 15).

All four sidewalls1506-1512of the depression1504have at least one stiffener edge feature1514,1516or1518formed thereon. Each stiffener edge feature comprises a protrusion, rib, dimple or indent. The stiffener edge features on each sidewall can be of the same or different types. For example, the stiffener edge features1514on sidewalls1506and1510comprise convex ribs extending in a direction towards the center of the housing. In contrast, the stiffener edge features1516,1518of sidewalls1508,1512comprise indents extending in a direction away from the center of the housing. In all scenarios, each stiffener edge feature may have a dome shape as shown inFIG. 15, a square shape, a rectangular shape, a triangular shape or any other shape suitable for providing structural strength to the marker housing. Some or all of the dome shaped stiffener edge features can have the same or different radii.

Any number of stiffener edge features can be provided on each sidewall1506-1512of the depression1504. For example, ten stiffener edge features1514are provided on each sidewall1506and1510. In contrast, a single stiffener edge feature1516or1518is provided an each sidewall1508and1512. The stiffener edge features on each sidewall can have equal spacing therebetween or non-equal spacing therebetween. The spacing between the stiffener edge features of each sidewall can be the same as or different than that of the other sidewalls. The spacing between the outer most stiffener edge features of each sidewall and the respective sidewall end can be the same or different for each sidewall.

Referring now toFIGS. 16-17, there is provided a schematic illustration of another exemplary architecture for a top portion1600of a marker's housing. Top portion1600is the same as or substantially similar to top portions700with a few exceptions which will be described below. As such, the discussion provided above in relation toFIGS. 7-11is suitable for understanding the general architecture of top portion1600(especially the stiffener edge features formed on the elongate sidewalls thereof).

As shown inFIGS. 16-17, the top portion1600includes wall1602having a hatch stiffener feature1604formed thereon. The hatch stiffener feature1604comprises a plurality of linear protrusions which extend out and away from the wall1602. The linear protrusions are arranged relative to each other so as to collectively form a woven mesh-like structure. Ends of the woven mesh-like structure may be respectively crossed by linear end protrusions1606. The woven mesh-like structure and linear end protrusions1606provide additional strength to the wall1602.

Referring now toFIG. 18, there is provided a flow diagram of an exemplary method1800for making a marker housing. Method1800begins with step1802and continues with step1804. Step1804involves forming a first housing portion from a flexible material so as to have a planar shape. Next in step1806, a second housing portion is formed from the flexible material so as to comprise a cavity in which resonator and bias elements of the marker can be housed when the second housing portion is coupled to the first housing portion. The cavity is defined by two opposing short sidewalls, two opposing elongate sidewalls and a bottom sidewall.

The two opposing elongate sidewalls are stiffened in step1808such that crushing and bending thereof is made difficult. The stiffening is achieved by forming a plurality of first stiffener edge features along an exterior surface of each of the two opposing elongate sidewalls which partially define the cavity of the second housing portion. The first edge features are disposed along a respective one of the two opposing elongate sidewalls so as to have equal or non-equal spacing between adjacent ones thereof. Each of the first stiffener edge features may: extend more than 50% of an entire height of a respective one of the two opposing elongate sidewalls of the second housing portion; comprise a shaped hollow or solid structure protruding out and away from the second housing portion; and/or have a dome shape.

After completing step1808, method1800may continue with one or more optional steps1810-1814. In step1810, a depression is optionally formed in the bottom wall of the second housing portion which extends into the cavity. A plurality of second stiffener edge features may optionally be formed on two opposing elongate sidewalls partially defining the depression, as shown by step1812. In this case, a center axis of one of the first stiffener edge features is offset from a center axis of an adjacent one of the second stiffener edge features. At least one third stiffener edge feature may optionally be formed on each of two opposing short sidewalls partially defining the depression, as shown by step1814. Upon completing step1814, step1816is performed where method1800ends or other processing is performed.

Notably, the cavity of the second housing portion, the first stiffener edge features, the depression, the second stiffener edge features and the third stiffener edge feature can be formed concurrently with each other. As such, steps1806-1814can be performed simultaneously or concurrently with each other.

The features and functions disclosed above, as well as alternatives, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations or improvements may be made by those skilled in the art, each of which is also intended to be encompassed by the disclosed embodiments.