Abstract:
This application relates to methods and apparatus pertaining to a SIM tray that includes a deformable portion. When the SIM tray is subjected to stresses that result from tolerance stacking, the deformable portion accommodates the differences tolerance errors by allowing the non-deformable portion of the SIM tray to move substantially independently from one another. Creating the deformable portion can be accomplished by utilizing materials with lower relative moduli of elasticity, dovetails, magnets, or other means.

Description:
FIELD 
       [0001]    This paper describes various embodiments that relate to mobile telephony devices such as a mobile telephone. More specifically, a user accessible tray that allows users to swap out components such as a subscriber identification module (SIM) card is described. 
       BACKGROUND 
       [0002]    Subscriber identification module (SIM) cards are generally removable cards for mobile devices that include integrated circuits that store subscriber information for the mobile devices. SIM cards are typically supported within a mobile device by a user accessible tray, which typically slides in and out of the mobile device. The user accessible tray should perform two essential functions: (1) facilitate easy access and removal of the SIM card, and (2) when inserted into a mobile device, maintain a seamless external cosmetic appearance in relation to a housing of the mobile device. However, SIM trays can be prone to deformation once inserted into a mobile device as a result of a phenomenon known in the art as tolerance stacking. When tolerance stacking causes a substantial misalignment between an external opening in the mobile device and internal connectors configured to mate with the SIM card, the user accessible tray can be subjected to substantial stresses. As a result, the user accessible tray can deform, which can make it more difficult for the user to remove the tray. In some cases, misalignment of internal and external features can cause an external portion of the SIM tray to deform in a way that prevents the external portion from matching a surrounding exterior surface of the housing of the mobile device, thereby marring an external cosmetic appearance of the mobile device. 
       SUMMARY 
       [0003]    This paper describes various embodiments that relate to methods and apparatus for cosmetically aligning a subscriber identification module (SIM) tray with a SIM tray opening of a portable electronic device. 
         [0004]    A subscriber information module (SIM) tray assembly is disclosed that is utilized with a portable electronic device. The SIM tray assembly can include an external portion designed to cover an opening in a housing of the portable electronic device. The opening can take the form of a slot for the SIM tray. The SIM tray assembly can also include a tray portion designed to hold a SIM card with an opening disposed on the SIM tray assembly. The SIM tray assembly also includes a compliant part forming a joint between the tray portion and the external portion. The compliant part can adjust for tolerances between internal and external features of the portable electronic device. 
         [0005]    A subscriber information module (SIM) tray is disclosed that can include an external portion and a tray portion. The external portion can cover a SIM slot of a mobile device. The tray portion can include an opening configured to hold a SIM card. The SIM tray can also include an interface located between the tray portion and the external portion. The interface can constrain relative movement between the external portion and the tray portion in a first direction parallel to a surface of the tray portion that is configured to hold the SIM card while also facilitating movement between the external portion and the tray portion in a second direction perpendicular to the first direction. 
         [0006]    A mobile device is disclosed that includes a housing forming an interior volume, a slot defined by the housing that allows access to the interior volume from outside the housing and an electrical components positioned within the interior volume that includes a number of electrical components. A subscriber identification module (SIM) tray assembly is inserted into the slot so that a SIM card supported by the SIM tray assembly contacts the of electrical contacts. The SIM tray assembly includes at least the following: an external portion that covers the slot of the mobile device and sits flush with an exterior surface the housing; a tray portion that supports the SIM card; and a flexible region connecting the external portion to the tray portion, the flexible region configured to allows the tray portion to shift with respect to the external portion to accommodate manufacturing tolerances that cause an offset between a location of the slot and a location of the plurality of electrical contacts. 
         [0007]    Other aspects and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the described embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
           [0009]      FIG. 1  shows a perspective view of an illustrative mobile device suitable for use with the described embodiments; 
           [0010]      FIG. 2A  shows a cross-sectional view of the mobile device in accordance with section line A-A of  FIG. 1 ; 
           [0011]      FIG. 2B  shows a cross-sectional view of the mobile device in accordance with section line A-A of  FIG. 1 ; 
           [0012]      FIG. 3A  shows a perspective view of a composite SIM tray assembly; 
           [0013]      FIG. 3B  shows a cross-sectional view of the mobile device utilizing the composite SIM tray assembly in accordance with section line A-A of  FIG. 1 ; 
           [0014]      FIG. 4A  shows an isometric view of various illustrative embodiments of a SIM tray; 
           [0015]      FIG. 4B , shows an isometric view of various illustrative embodiments of a SIM tray; 
           [0016]      FIG. 5  shows an isometric view of a dovetailed SIM tray assembly; 
           [0017]      FIG. 6  shows an exploded view illustrating an embodiment of a SIM tray assembly; 
           [0018]      FIG. 7A  shows a perspective view of a mobile device suitable for use with the described embodiments and a close up view of the SIM tray; 
           [0019]      FIG. 7B  shows a cross-sectional view of the mobile device in accordance with section line B-B of  FIG. 7A  with the SIM tray placed within a slot in a housing of the mobile device; 
           [0020]      FIG. 7C  shows a cross-sectional view of the mobile device in accordance with section line A-A of  FIG. 1  where the mobile device is subjected to tolerance stacking; and 
           [0021]      FIG. 8  shows a flow chart describing methods of manufacturing and utilizing the SIM tray. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    Representative applications of methods and apparatus according to the present application are described in this section. These examples are being provided solely to add context and aid in the understanding of the described embodiments. It will thus be apparent to one skilled in the art that the described embodiments may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order to avoid unnecessarily obscuring the described embodiments. Other applications are possible, such that the following examples should not be taken as limiting. 
         [0023]    In the following detailed description, references are made to the accompanying drawings, which form a part of the description and in which are shown, by way of illustration, specific embodiments in accordance with the described embodiments. Although these embodiments are described in sufficient detail to enable one skilled in the art to practice the described embodiments, it is understood that these examples are not limiting; such that other embodiments may be used, and changes may be made without departing from the spirit and scope of the described embodiments. 
         [0024]    A subscriber identification module (SIM) card is an integrated circuit that securely stores service and subscriber information used to identify the subscriber on mobile telephony devices, such as a mobile telephone. A SIM tray is a user accessible tray utilized in mobile telephony devices that is adapted to receive and secure the SIM card within the mobile device. A SIM tray generally includes a tray portion that supports the SIM card rigidly joined to an external portion that covers an opening in a housing of the mobile device. The SIM tray should perform two essential functions: (1) facilitate easy access and removal of the SIM card, and (2) when inserted into a mobile device, maintain a seamless external cosmetic appearance in relation to a housing of the mobile device. However, SIM trays can be prone to deformation once inserted into a mobile device as a result of manufacturing tolerances in both the opening that facilitates insertion of the SIM tray and the positioning and dimensioning of internal components configured to support and mate with the SIM card. These manufacturing tolerances can generate offsets that cause the rigid coupling between the tray portion and the external portion to experience substantial stresses. Because the tray portion of the SIM tray is engaged by internal coupling features that align and position the SIM card with respect to internal connectors, when the external portion of the SIM tray contacts the surfaces forming the opening, the external portion is forced to deform to accommodate any offsets causing misalignment between the opening and the internal components. Accordingly, deformation of the external portion of the SIM tray can cause the external portion of the SIM tray to deviate relative to the housing, thereby adversely affecting the external cosmetic appearance between the SIM tray and the housing of the mobile device. 
         [0025]    Moreover, the aforementioned bending of the SIM tray can increase the stress and strain applied to the internal electrical components of the mobile device. Consequently, electrical contacts between the SIM card and the internal electrical components can be damaged due the SIM tray bending. Furthermore, over time the SIM tray can become permanently bent or in severe cases break from being subjected to the constant stress and strain. As a result, binding can develop between the housing of the mobile device and the SIM tray during removal of the SIM tray. These limitations may be remedied by reducing manufacturing tolerances of the parts; unfortunately, such machinery can be substantially more expensive and in some cases can substantially increase an amount of time spent to produce the part and/or the device due to processes associated with the higher precision manufacturing operations. 
         [0026]    One solution to the aforementioned problem is to build a compliant portion into a SIM tray assembly that joins the external portion to the tray portion. The compliant portion can be designed to accommodate both the internal and external manufacturing tolerance ranges associated with the mobile device. The compliant portion of the SIM tray assembly allows the external portion of the SIM tray to shift or deflect with respect to the tray portion without adversely affecting other portions of the SIM tray assembly. Moreover, the compliant portion of the SIM tray can allow the tray portion of the SIM tray to move independently of an external portion of the SIM tray. In this way, substantial tolerance mismatches of components contacting the tray portion of the SIM tray will not adversely affect the external portion. 
         [0027]    In some embodiments, the compliant portion can take the form of an elastomeric polymer that forms an interface between the internal and external portions of the SIM tray. In such a configuration, the elastomeric polymer acts as a point of deflection once the SIM tray is fully inserted into the mobile device. Once inserted, the tray portion of the SIM tray is free to travel within the mobile device as a result of the interface being flexible. Moreover, the external portion of the SIM tray can remain fixed and unaffected from movement of the tray portion. Alternatively, the compliant portion can take the form of a series of interlocking features that form an interface between the internal and external portions of the SIM tray. Furthermore, the series of interlocking features can decouple horizontal movement of the tray portion from the external portion. In this way, the tray portion of the SIM tray does not have to deflect in order to interact with the internal electrical components but instead can translate into a proper position. In some embodiments, the compliant portion can include a series of magnets that form the interface between the internal and external portions of the SIM tray. The magnetic coupling permits self-alignment of the external portion of the SIM tray with the opening in the housing without exerting any continuous force upon the tray portion of the SIM tray. 
         [0028]    In some embodiments, the SIM tray can be machined or formed from a single piece of material and an interface between the tray portion and the external portion is optimized by removing material from the interface until a desired balance between flexibility and structural integrity is achieved at the interface. The material can be removed in any number of ways and in any number of patterns. For example, in some embodiments, a number of holes can be drilled at the interface. In other embodiments, a unitary opening can be formed to achieve the desired balance. In this way, the flexible interface joining the tray portion to the external portion can allow deflection of the external portion without substantially affecting the rigid region of the tray portion supporting the SIM card. 
         [0029]    These and other embodiments are discussed below with reference to  FIGS. 1-8 ; however, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes only and should not be construed as limiting. 
         [0030]      FIG. 1A  shows a perspective view of an illustrative mobile device suitable for use with the described embodiments. In some embodiments, mobile device  100  can be a mobile telephony device along the lines of a mobile telephone. Mobile device  100  can include housing  102  that creates an internal volume for positioning and protecting a number of electronic components that include at least circuitry for supporting display  104 . Housing  102  can also take the form of multiple housing components that cooperate to define the internal volume for positioning and protecting the electronic components. Housing  102  can also include an opening, which can take the form of slot  106  for receiving, positioning, and protecting SIM tray  108 . SIM tray  108  is a user accessible tray utilized by mobile device  100  to secure SIM card  110 . For example, SIM tray  108  can include an opening for accommodating and supporting SIM card  110  while leaving a substantial portion of a bottom surface of SIM card  110  exposed so that electrical contacts on SIM card  110  can mate with electrical contacts of mobile device  100 . SIM card  110  is an integrated circuit that securely stores service and subscriber information used to identify the subscriber on mobile devices. When SIM tray  108  is inserted into slot  106 , SIM tray  108  is positioned in such a manner that allows SIM card  110  to interact with the electronic components in housing  102 . SIM tray  108  can be positioned by housing  102  or electronic components located in the interior volume of housing  102 . Additionally, when SIM tray  108  is inserted into housing  102 , an exterior portion of SIM tray  108  that is exposed to the exterior of housing  102  can be substantially flush or parallel with external surface  112  of housing  102 . When the exterior portion of SIM tray  108  is substantially flush or parallel to exterior surface  112  a desirable cosmetic appearance can be achieved. 
         [0031]      FIG. 2A  shows a cross-sectional view of mobile device  100  in accordance with section line A-A of  FIG. 1  with SIM tray  108  placed within slot  106  in housing  102  of mobile device  100 . As depicted, SIM tray  108  is fully inserted within slot  106 . SIM tray  108  is depicted in an ideal position causing the external portion of SIM tray  108  to be substantially flush or parallel to surface  112 . Housing  102  can include chamfers or guiding features that aid in positioning SIM tray  108  as it slides into slot  106 . When inserted into mobile device  100 , SIM tray  108  is positioned in such a manner that allows SIM card  110 , placed within the receptacle in SIM tray  108  which places SIM card  110  just above electrical component  202  so that SIM card  110  can interact with electrical contacts  204 . In some embodiments, electrical component  202  can be a main logic board (MLB). 
         [0032]    Electrical component  202  occupies a height D 1  within mobile device  100 . In some embodiments, electrical component  202  can be a main logic board (MLB). Standoffs  206  occupy a height D 2  and can support electrical component  202  above an interior surface of housing  102 . The interior surface of housing  102  is defined by a housing wall, which has a thickness D 3 . In the case where contacts  204  form a substantially flat surface, SIM tray  108  is positioned substantially parallel to a top surface of electrical component  202  once inserted into mobile device  100 . The sum of D 1 , D 2 , and D 3  can be equal to a distance D total . D total  can be critical in a design such as a position of slot  106  in housing  102  in order to position SIM tray  108  and assure that SIM tray  108  remains substantially flush or parallel to surface  112  advantageously creating a desirable cosmetic appearance. Designers can take into account D total  to achieve the desirable cosmetic appearance or other design goals. 
         [0033]      FIG. 2B  shows a cross-sectional view of mobile device  100  in accordance with section line A-A of  FIG. 1  where internal components of device  100  are out of position as a result of tolerance stacking. Tolerance stacking occurs when a number of manufactured component suffer dimensional defects. Tolerance stacking is a phenomenon that occurs when the manufactured components are manufactured at the maximum allowable dimensions and the component variations sum or “stack” together to cause design defects such as clearance issues. In many cases, tolerance stacking can be difficult to control and be an unavoidable aspect of the manufacturing of multiple identical or similar parts. Electrical component  202 , housing  102 , and standoffs  206  can be manufactured components. Therefore, Electrical component  202 , housing  102 , and standoffs  206  can be subject to tolerance stacking. The sum of the actual heights of electrical component  202 , housing  102 , and standoff  206 , D actual , can be substantially greater than the designed sum of components heights D Total . The difference between D actual  and heights D 1 , D 2 , and D 3  can be D ERROR . In some cases, D ERROR  may not be taken into account by designers in positioning slot  106 . As a result, stress can be concentrated at interface  208  which can cause SIM tray  108  to bend. Consequently, SIM tray  108  will no longer be substantially parallel to surface  112  or electrical component  202 . In some embodiments, communication between SIM card  110  and electrical component traces  204  can be substantially inhibited. Additionally, mobile device  100  may malfunction due to a miscommunication between SIM card  110  and electrical component  202  as a result of SIM tray  108  not being substantially parallel to surface  112 . Moreover, tolerance stacking can create substantial stress and strain, such as stress concentrations at interface  208 , thereby causing SIM tray  108  to elastically deform or even structurally fail. Further, tolerance stacking can cause tray  108  to no longer remain substantially flush or parallel to surface  112  causing the exterior of mobile device  100  to no longer be aesthetically appealing. In some embodiments, both the external portion of SIM tray  108  and the tray portion can deflect and be biased out of position as a result of severe cases of tolerance stacking. In some cases, deformation of the external portion can cause the external portion to protrude away from an exterior surface of the mobile device, which could cause the external portion to catch on external objects, potentially causing damage to mobile device  100 . 
         [0034]      FIG. 3A  shows an isometric view of SIM tray assembly  300  in accordance with some embodiments. In some embodiments, SIM tray assembly  300  can include tray portion  302 , external portion  304 , and flexible portion  306 . Tray portion  302  can include receptacle  308  that is utilized to hold a SIM card such as SIM card  110 . Tray portion  302 , external portion  304 , and flexible portion  306  can be formed from different materials. Flexible portion  306  can form an interface between tray portion  302  and external portion  304 . In some embodiments, flexible portion  306  can be adhesively coupled to tray portion  302  and external portion  304 . In some embodiments, flexible portion  306  can be formed from a material with a lower relative modulus of elasticity than the modulus of elasticity of the materials used to form tray portion  302  and external portion  304 . For example, tray portion  302  and external portion  304  can be made from a metal such as aluminum or steel. In other embodiments, tray portion  302  can be made from a polymer. While tolerance stacking can still cause stress concentrations to be applied along flexible portion  306 , flexible portion  306  can dissipate the stress by flexing to dissipate the applied stresses. While flexible portion  306  isn&#39;t infinitely stretchable it can be designed to accommodate an amount of stress expected from tolerance stacking 
         [0035]    To illustrate,  FIG. 3B  shows a cross-sectional view of mobile device  100  utilizing SIM tray assembly  300  in accordance with section line A-A of  FIG. 1 . In some embodiments, external portion  304  can fit tightly within slot  106  of housing  102 , thereby inhibiting containments from entering the interior of housing  102 . In some embodiments, external portion  304  can utilize a rubber gasket located at an interface between external portion  304  and housing  102  to more substantially prevent continents from entering the interior of housing  102  through slot  106 . SIM tray assembly  300  can be utilized to accommodate tolerance stacking of internal components of mobile device  100 . For example, SIM tray assembly  300  can be inserted into mobile device  100  in the same manner as SIM tray  108 . In this particular embodiment, tolerance stacking can cause a stress concentration to form at flexible portion  306 . Flexible portion  306  can be formed from various durometers of rubber, elastomeric polymers, silicon, or any suitable material with a lower modulus of elasticity than the material that forms tray portion  302  and/or external portion. As a result, flexible portion  306  can deform by a greater magnitude than tray portion  302  and/or external portion  304  for a given stress. Therefore, when subjected to a tolerance stacking phenomenon, flexible portion  306  may bend, deform or comply by a greater magnitude than tray portion  302  and external portion  304 . As a result, tray portion  302  and external portion  304  can bend, deform, or comply by a substantially lower magnitude relative to flexible portion  306 . Therefore, tray portion  302  and electrical component  202  may remain substantially parallel to each other. In this way, tray portion  302  is not adversely affected by tolerance stacking and communication between SIM card  110  and electrical component  202  can be maintained. Additionally, flexible portion  306  can be utilized to maintain a smooth interface between external portion  304  and housing  102 . In this way, tolerance stacking may allow external portion  304  to be flush with surface  112  thereby providing an aesthetically appealing exterior for mobile device. 
         [0036]      FIG. 4A  shows an isometric view of various illustrative embodiments of SIM tray  400 . SIM tray  400  can be monolithic and formed from a single material such as a polymer, aluminum, steel, or any material that can be cut, machined, and/or molded. SIM assembly  400  can include tray portion  402  and external portion  404 . Moreover, tray portion  402  can include flexible region  406  and rigid region  408 . Rigid region  408  can support a SIM card such as SIM card  110 . Flexible region  406  can include one or more openings which define a number of arms  410 . Thus,  402  remains attached to external portion  404  via arms  410 . In some embodiments material can be removed from both top and lateral surfaces of flexible region  406  to increase flexibility of flexible region  406 . As more material is removed from flexible region  406 , an amount of force required to bend flexible region  406  is reduced, thereby reducing an amount of stress endured by SIM tray  400  when inserted within a mobile device. Although flexible region  406  and rigid region  408  are formed from the same material, flexible region  406  can deform by a greater magnitude for a given stress than rigid region  408 . Tolerance stacking can cause stress concentrations to form at flexible region  406  and create a potential weak point on SIM tray  400 . Flexible region  406  is designed to compensate for this stress concentration and alleviate problems associated with the stress concentrations. 
         [0037]    As shown in  FIG. 4B , flexible region  406  can also take the form of series of holes  412  in SIM tray  450 . SIM tray  450  can have tray portion  402  and external portion  404 . Tray portion can include a rigid region  408  capable of receiving a SIM card and flexible region  406 , capable of deforming by a greater magnitude for a given stress than one or both of rigid region  408  and external portion  404 . Deforming by a greater magnitude for a given stress can be achieved by removing material from flexible region  406  such as the removal of material accomplished by series of holes  412 . Holes  412  can take many forms depending on the desired flexibility of SIM tray  450  and other manufacturing considerations. For example, drilling a quantity of large diameter holes may result in the same deformation for a given stress as a larger quantity of small diameter holes. In this way, a desired balance between flexibility and structural integrity can be achieve while manufacturing expenses can be substantially reduced. In some embodiments, holes  412  can include many small holes as shown in  FIG. 4B . Small holes may be desirable to achieve a more precise flexibility to structural integrity ratio, which could not be achieved using large cumbersome drills. Each additional small hole can incrementally increase a flexibility of flexible region  406 . Furthermore, tray portion  402  made from certain materials, such as a hard plastic, may be susceptible to cracking. Therefore, it may be desirable to use fewer, and further spaced series of holes  412  to avoid cracking flexible region  406 . 
         [0038]      FIG. 5  shows an isometric view of dovetailed SIM tray assembly  500 . SIM tray assembly  500  can be utilized in mobile device  100 . In some embodiments, SIM tray assembly  500  can include tray portion  502  and external portion  504 .  FIG. 5  also shows a close up view depicting a dovetail feature that can form an interface between tray portion  302  and external portion  304 . Tray portion  502  can join to external portion  504  by utilizing joints  506 . Tray portion  502  can also join external portion  504  by utilizing a number of joints. Joint  506  can substantially limit movement of tray portion  502  and external portion  504  relative to each other in x and y directions. However, joint  506  can allow the positions of tray portion  502  and external portion  504  to float relative to each other in z direction. Freedom of movement between tray portion  502  and external portion  504  would be desirable in the event that stress concentrations would form at region  510 , a potential weak point of SIM tray assembly  500 . For example, region  510  could be analogous to stress concentrations at interface  208  depicted in  FIG. 2 . In some embodiments, external portion  504  can further comprise a rubber gasket. 
         [0039]      FIG. 5  also shows a close up view showing a particular joint  506 . External portion  504  can include channel  512  defined by an interior facing surface of external portion  504 . Channel  512  can take the form of a square, rectangular, or curved slot. Tray portion can include protrusion  514  integrally formed within the tray portion. Protrusion can be adapted for insertion into channel  512 . Channel  512  can be shaped to accept protrusion  514  and trap a distal end of protrusion  514  within channel  512 . For example, a trapezoidal or fan shape can facilitate insertion in a direction but resist removal in a different direction. Channel  512  and protrusion  514  can cooperate to form joint  506  which can take the form of a tight interlocking joint that can be rigid in x and y directions but not in z direction. In some embodiments, channel  512  can be oriented in a direction to allow movement of the external portion  504  in the direction. Tray portion  502  can include receptacle  508  that is utilized to hold a SIM card. A lubricant or a coating that increases lubricity can facilitate movement in z direction. 
         [0040]    SIM tray assembly  500  can also be utilized to accommodate tolerance stacking of internal components of mobile device  100 . For example, SIM tray assemblies  400  and  450  can be inserted into mobile device  100  in the same manner as SIM tray  108 . In this particular embodiment, tolerance stacking can cause a stress concentration to form at region  510 . However, joint  506  can allow external portion  504  and tray portion  502  to translate relative to each other in the z direction to dissipate any stress concentration resulting from the tolerance stacking. Rather than deforming, joint  506  allows tray portion to translate by movement of protrusion  514  within channel  512 . Likewise, external portion can also translate in z direction. In this way, tray portion  502  is not adversely affected by tolerance stacking and communication between SIM card  110  and electrical component  202  can be maintained. Additionally, external portion  304  can be flush with surface  112  providing an aesthetically appealing exterior for mobile device. 
         [0041]    To illustrate,  FIG. 6  depicts an exploded perspective view of a specific implementation of SIM tray  600  utilizing a dovetail joint. SIM tray  600  includes tray portion  602  including mortise  612  and external portion  604  including tenon  614 . Tenon  614  can join to mortise  612  along axis  616  in order to form a dovetail joint. As depicted, tenon  614  can translate along axis  616  relative to external portion  604  according slot of mortise  612 . However, relative movement between tray portion  602  and external portion  604  in directions perpendicular to axis  616  is substantially limited by the cooperation of tenon  614  and mortise  612 . 
         [0042]      FIG. 7A  depicts a perspective view of illustrative mobile device  100  suitable for use with the described embodiments and a close up view SIM tray  700 . Mobile device  100  includes housing  102  that creates an internal volume for positioning and protecting a number of electronic components. Housing  102  can also take the form of multiple housing components that cooperate to define the internal volume for positioning and protecting the number of electronic components. Housing  102  may also include slot  106  for receiving SIM tray  700 . In some embodiments, SIM tray assembly  700  can include external portion  702  and tray portion  704 . Tray portion  704  can join to external portion  702  by utilizing a magnetic force. The magnetic force can be provided by magnets  706  embedded in external portion  702 . The magnetic force can substantially limit movement of tray portion  704  and external portion  702  relative to each other in x and/or y directions. However, the magnetic force can allow the positions of tray portion  704  and external portion  702  to float relative to each other in z direction. 
         [0043]      FIG. 7B  shows a cross-sectional view of mobile device  100  in accordance with section line B-B of  FIG. 7A  with SIM tray  700  placed within slot  106  in housing  102  of mobile device  100 . As depicted, SIM tray  700  is fully inserted within slot  106  forming the part of SIM tray  700  that is substantially flush or parallel to surface  112 . Housing  102  can have chamfers that aid in positioning SIM tray  700  relative to housing  102  when inserted. Magnets  706  can be embedded in external portion  702 . Magnets  706  can be attracted to tray portion  704 . In other embodiments, tray portion  704  can also contain magnets  708 . Magnets  706  and  708  can also be any pair of materials that are magnetically attracted to each other. For example, magnet  706  can be formed from ferromagnetic material and magnet  708  can be a rare earth magnet. In lieu of magnets  706 , tray portion  704  can be formed from a ferromagnetic material such as steel. When inserted into mobile device  100 , SIM tray  108  is positioned in such a manner that allows SIM card  110  positioned within the receptacle in SIM tray  700  to interact with electrical component  202  within mobile device  100 . External portion  702  can be flush with surface  112 . Electrical component  202  can be a main logic board (MLB). Standoffs  206  can support electrical component  202  on housing  102 . SIM card  110  can then electrically interact with electrical component  202  through contacts  204 . In the case where contacts  204  form a substantially flat surface, SIM tray  108  is positioned substantially parallel to electrical component  202  once inserted into mobile device. SIM tray  700  can remain substantially flush or parallel to surface  112  advantageously creating a desirable cosmetic appearance. 
         [0044]    To illustrate,  FIG. 7C  shows a cross-sectional view of mobile device  100  in accordance with section line A-A of  FIG. 1  where device  100  is subjected to tolerance stacking. SIM tray assembly  700  can be utilized to accommodate tolerance stacking of internal components of mobile device  100 . In this particular embodiment, housing  102 , standoffs  206 , and electrical component  202  can be manufactured components having dimensional errors. As a result of tolerance stacking phenomenon, SIM tray  700  can be moved by distance D ERROR . However, rather than deforming, tray portion  704  can translate in z direction in order to accommodate tolerance stacking. In this way, tray portion  704  is not adversely affected by tolerance stacking and communication between SIM card  110  and electrical component  202  can be maintained. Additionally, external portion  702  can remain be flush with surface  112  thereby providing an aesthetically appealing exterior for mobile device. A lubricant or a coating that increases lubricity can facilitate movement of external portion  702  in the z axis. Additionally, magnets  706  and  708  can also facilitate relative movement between external portion  702  and tray portion  704  in both the z and x directions. In other embodiments, housing  102  can also include a number of magnets. For example, magnets  708  can be located on housing  102  rather than tray portion  704 . In this case, magnets  708  and  706  can cooperate to allow translation in the z direction in order to accommodate tolerance stacking. 
         [0045]      FIG. 8  illustrates a flow chart depicting a method  800  for manufacturing and utilizing a SIM tray in accordance with an embodiment of the invention. As shown, method  800  begins at step  802 , which involves forming a tray portion for housing and positioning a SIM card and an external portion for forming a substantially flush surface with a housing of a mobile telephony device. Step  804  forming a compliant portion joining the tray portion to the external portion. For example, the tray portion and the external portion can be connected with a compliant material formed from as rubber, an elastomeric polymer, or any material with a lower modulus of elasticity than the materials that form the external portion or the tray portion. In some embodiments, the compliant portion can take the form of a compliant join such as a dovetail joint. For example, the tray portion could form a protrusion that can be inserted into a channel located on the external portion. In other embodiments, the compliant portion could take the form of magnets. Step  806  involves inserting the SIM tray assembly into the mobile telephony device. Because of the tolerance stacking phenomenon, the SIM tray could be subjected to a force. In step  808 , the compliant portion can allow the external portion to remain flush with the housing of the mobile device. In some embodiments, the compliant portion can deform (strain) by a greater magnitude than the tray portion and/or the external portion. In other embodiments, compliant portion can allow the tray portion and the external portion to translate in a direction. 
         [0046]    The various aspects, embodiments, implementations or features of the described embodiments can be used separately or in any combination. Various aspects of the described embodiments can be implemented by software, hardware or a combination of hardware and software. The described embodiments can also be embodied as computer readable code on a computer readable medium for controlling manufacturing operations or as computer readable code on a computer readable medium for controlling a manufacturing line. The computer readable medium is any data storage device that can store data which can thereafter be read by a computer system. Examples of the computer readable medium include read-only memory, random-access memory, CD-ROMs, HDDs, DVDs, magnetic tape, and optical data storage devices. The computer readable medium can also be distributed over network-coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. 
         [0047]    The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of specific embodiments are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the described embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.