PATENT DOCUMENT

Publication Number: US-10016921-B2
Application Number: US-201615059100-A
Country: US
Kind Code: B2

Title: Apparatus and method of forming a compound structure

Abstract:
Compound structures and methods for forming the same are described. The compound structures can be used to form an enclosure. The enclosure may be formed from metal, such as aluminum, and further include one or more non-metal regions that allow for transmission and receipt of electromagnetic waves, such as radio frequency waves. The non-metal region can include a first section, a second section, and an optional cosmetic section. The first section can be firmly molded onto a metal section of the enclosure by small pores formed within the metal section. The second section can engage with interlock features of the first section. The optional cosmetic section can cover the first section and the second section such that the first section and the second section are not visible from an exterior of the enclosure.

Claims:
The invention claimed is: 
     
       1. A compound structure comprising:
 a first metal section having a recess defining an interface surface, the interface surface having a pore with a diameter of less than one millimeter; 
 a second metal section; and 
 a radio-frequency (RF) transparent section including an RF transparent material, the RF transparent section being engaged with the interface surface of the first metal section and some of the RF transparent material being positioned within the pore. 
 
     
     
       2. The compound structure of  claim 1 , wherein the second metal section includes a second recess defining a second interface surface having a second pore, wherein the RF transparent section is engaged with the second interface surface of the second metal section and wherein some of the RF transparent material is positioned within the second pore. 
     
     
       3. The compound structure of  claim 1 , wherein the RF transparent section comprises a first RF transparent section and a second RF transparent section secured to the first RF transparent section, the first RF transparent section engaged with the interface surface of the first metal section and the second RF transparent section engaged with the second metal section. 
     
     
       4. The compound structure of  claim 3 , wherein the second RF transparent section is engaged with a second interface surface of the second metal section. 
     
     
       5. The compound structure of  claim 1 , wherein the RF transparent section comprises a fiber composite material including fibers within a resinous base. 
     
     
       6. The compound structure of  claim 1 , wherein the pore has a diameter less than one micrometer. 
     
     
       7. An enclosure for an electronic device, the enclosure comprising:
 a first metal section; 
 a second metal section; 
 a radio frequency (RF) transparent section securing the first metal section with the second metal section, the RF transparent section comprising:
 a first RF transparent material within the enclosure and having a portion incorporated within pores of the first metal section, the pores each having a diameter less than one millimeter; and 
 a second RF transparent material within the enclosure and secured to the first RF transparent material and to the second metal section. 
 
 
     
     
       8. The enclosure of  claim 7 , wherein the first metal section includes a first set of pores and the second metal section includes a second set of pores. 
     
     
       9. The enclosure of  claim 7 , wherein an exterior surface of the enclosure is defined in part by a surface portion of the first metal section and a surface portion of the second metal section. 
     
     
       10. The enclosure of  claim 9 , wherein the first RF transparent material and the second RF transparent material include corresponding interlock features interlocking the first RF transparent material and the second RF transparent material. 
     
     
       11. The enclosure of  claim 9 , wherein the first RF transparent material is composed of a different material than the second RF transparent material. 
     
     
       12. The enclosure of  claim 9 , wherein the enclosure includes a third RF transparent material that covers the first RF transparent material and the second RF transparent material. 
     
     
       13. The enclosure of  claim 12 , wherein the third RF transparent material fills a gap between the first metal section and the second metal section and defines a portion of the exterior surface of the enclosure. 
     
     
       14. The enclosure of  claim 7 , wherein the pores each have a diameter less than one micrometer. 
     
     
       15. The enclosure of  claim 7 , wherein the RF transparent section comprises fibers within a resinous base. 
     
     
       16. A method of forming an enclosure for an electronic device, the enclosure including a first metal section and a second metal section, the method comprising:
 forming pores at a recessed interface surface of the first metal section; 
 molding a first RF transparent section on the recessed interface surface such that a material of the first RF transparent section is molded within the pores and interlock features are formed within the first RF transparent section; and 
 coupling the first metal section to the second metal section by molding a second RF transparent section on the second metal section and the first RF transparent section, including molding the second RF transparent section within the interlock features of the first RF transparent section. 
 
     
     
       17. The method of  claim 16 , wherein the first RF transparent section includes fibers within a resinous base. 
     
     
       18. The method of  claim 16 , wherein molding the first RF transparent section on the recessed interface surface of the first metal section comprises: injecting the material of first RF transparent section while in a molten state in a direction substantially orthogonal to the recessed interface surface. 
     
     
       19. The method of  claim 16 , further comprising: molding a cosmetic RF transparent section of the RF transparent section on the first RF transparent section and the second RF transparent section such that the cosmetic RF transparent section covers the first RF transparent section and the second RF transparent section. 
     
     
       20. The enclosure of  claim 7 , wherein an exterior surface of the enclosure does not include the first RF transparent material or the second RF transparent material.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 62/156,143, entitled “APPARATUS AND METHOD OF FORMING A COMPOUND STRUCTURE,” filed on May 1, 2015, which is incorporated by reference herein in its entirety. 
    
    
     FIELD 
     The described embodiments relate generally to forming compound structures. In particular, the present embodiments relate to forming compound structures that can be used with an enclosure used for electronic devices. More specifically, a structure having a radio frequency (RF) transparent section and an RF opaque section can be formed. 
     BACKGROUND 
     Many electronic devices include an antenna or multiple antennas capable of receiving and/or transmitting electromagnetic (“EM”) energy in the form of EM radio waves. Typically, the antenna(s) are enclosed within an enclosure that houses several other electronic components. In some cases, the enclosure is formed from a metal, such as aluminum or aluminum alloy, which can interfere with transmission and receipt of EM radio waves. In these cases, the enclosure may include a non-metal section that allows EM radio waves to permeate through the enclosure. 
     It may be difficult, however, to attach a non-metal material to a metal material with a strong enough bond to withstand some of the forces experienced by the electronic device. For example, if the bond is not strong enough, a force created by a drop event can cause disengagement of the metal and non-metal portions. Adhesives can be used to help secure the metal and non-metal portions. However, even thin layers of adhesive can be visible and detract from the aesthetic appeal of the enclosure. Fasteners, such as clip and screws, can be used to reinforce the bond. However, fasteners can also be visible and unattractive, or they can take up valuable space within the enclosure that can be used for internal components of the electronic device. 
     SUMMARY 
     This paper describes various embodiments that relate to forming enclosures for electronic devices that include radio frequency opaque sections, such as metal sections, and radio frequency transparent sections, such as plastic sections. The methods involve forming radio frequency transparent structures that are strongly bonded to the metal sections and that provide improved radio transmission and/or cosmetic appeal compared to conventional methods. 
     According to one embodiment, a compound structure is described. The compound structure includes a first metal section having a recess defining an interface surface. The interface surface has a pore with a diameter of less than one millimeter. The compound structure also includes a second metal section. The compound structure further includes a radio-frequency (RF) transparent section including an RF transparent material. The RF transparent section is engaged with the interface surface of the first metal section and wherein some of the RF transparent material is positioned within the pore. 
     According to another embodiment, an enclosure is described. The enclosure includes the enclosure having a first metal section and a second metal section. The enclosure includes an RF transparent section securing the first metal section with the second metal section. The RF transparent section is formed of an RF transparent material incorporated within pores of at least one of the first metal section or the second metal section. The pores have diameters of less than one millimeter. 
     According to a further embodiment, a method of forming an enclosure for an electronic device is described. The enclosure includes a first metal section and a second metal section. The method includes forming pores at an interface surface of the first metal section. The method also includes molding a first RF transparent section on the interface surface such that material of the first RF transparent section is molded within the pores. Molding the first RF transparent section includes forming interlock features within the first RF transparent section. The method further includes coupling the first metal section to the second metal section by molding a second RF transparent section on the second metal section and the first RF transparent section. The second RF transparent section is molded within the interlock features of the first RF transparent section. 
     These and other embodiments will be described in detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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. 
         FIG. 1  shows an electronic device including an enclosure, in accordance some embodiments. 
         FIG. 2  shows a cross section view of a portion of the enclosure of  FIG. 1 , in accordance with some embodiments. 
         FIGS. 3A-3C  show a cross section views of a portion of the enclosure of  FIG. 1 , in accordance with some other embodiments. 
         FIGS. 4A-4E  show perspective views of the enclosure of  FIG. 1  being formed, in accordance with some embodiments. 
         FIG. 5  shows a flowchart indicting a process for forming an enclosure, in accordance with some embodiments. 
     
    
    
     Those skilled in the art will appreciate and understand that, according to common practice, various features of the drawings discussed below are not necessarily drawn to scale, and that dimensions of various features and elements of the drawings may be expanded or reduced to more clearly illustrate the embodiments of the present invention described herein. 
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims. 
     Described herein are enclosures that can be used to house components that transmit and/or receive electromagnetic waves (e.g., radio frequency (RF) waves) for communications. The enclosures include RF opaque sections that generally do not allow transmission of RF waves to a sufficient degree for efficient communication. Such materials can include metal, which can provide a durability and aesthetic look and feel to the enclosure. The enclosures also include RF transparent sections that generally allow sufficient transmission of RF waves for efficient communication. Such materials can include plastic, ceramic, glass and combinations thereof. The RF transparent section(s) can be positioned proximate to antenna(s) housed within the enclosure that are designed to transmit and/or receive electromagnetic wave communications. 
     In a particular embodiment, the RF transparent section includes a structural RF transparent section, which can be made of a high strength resinous material, and a mediating RF transparent section, which can act to increase a transmission region of the enclosure. The mediating RF transparent section can be tightly secured to a first RF opaque section, and the structural RF transparent section can be tightly secured to a second RF opaque section. The structural RF transparent section and the mediating RF transparent section can interlock with each other using a molding process, thereby firmly coupling the first and second RF opaque sections of the enclosure. The RF transparent section can be in the form of a band that fills a gap between the RF opaque sections, creating an enclosure with a unique RF antenna region or gap that potentially increases antenna performance. 
     One or both of the mediating RF transparent section and structural RF transparent section can be interlocked with pore structures formed within the first and/or second RF opaque sections. The pores are generally very small, on a scale of micrometers or nanometers, providing ample surface area for extra-tight adhesion between the RF transparent section and the RF opaque sections. In some embodiments, the RF transparent section includes a cosmetic RF transparent section that covers the structural RF transparent section and the mediating RF transparent section, providing an aesthetically appealing exterior surface to the enclosure. 
     Methods described herein are well suited for providing cosmetically appealing structures for consumer products. For example, the methods described herein can be used to form cosmetically appealing housing or enclosures for mobile electronic devices, wearable electronic devices, portable computers, desktop computers, and electronic device accessories, such as those manufactured by Apple Inc., based in Cupertino, Calif. 
     These and other embodiments are discussed below with reference to  FIGS. 1-5 . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these Figures is for explanatory purposes and should not be construed as limiting. 
       FIG. 1  shows a rear view of electronic device  100 , in accordance with some embodiments. In some embodiments, electronic device  100  is a mobile phone. In some embodiments, electronic device  100  is a tablet computing device. Electronic device  100  can include enclosure  102  that includes an internal cavity (not shown) that is sized and shaped to house internal components, such as one or more electromagnetic wave antennas (not shown). In some embodiments, the electromagnetic wave antenna(s) transmit and/or receive radio frequency (RF) wave communication, and can be referred to as RF antenna(s). RF transmission refers generally to the transmission of at least some frequencies within the RF spectrum. RF communication refers generally to communication using transmission and/or receipt of at least some frequencies within the RF spectrum. Examples of RF communications can include Wi-Fi radio, Bluetooth radio, cellular radio, and/or NFC radio communications. 
     Enclosure  102  includes first metal section  104 , second metal section  106 , and third metal section  108 , which can be coupled by first RF transparent region  110  and second RF transparent region  112 . First RF transparent region  110  and second RF transparent region  112  are RF transparent such that one or more RF antennas housed within enclosure  102  can receive or transmit RF communication through enclosure  102  via first RF transparent region  110  and second RF transparent region  112 . First metal section  104  and third metal section  108  can be referred to as end pieces since they define ends of enclosure  102 . Second metal section  106  can be referred to as a chassis since it can defines main side walls of enclosure  102 . In some embodiments, first RF transparent region  110  and second RF transparent region  112  can appear as thin bands or lines that span a width of enclosure  102 , and therefore can be referred to as antenna bands or antenna lines. In some cases, first RF transparent section  110  and second RF transparent region  112  are referred to as splits or split regions of enclosure  102 . 
     First metal section  104 , second metal section  106 , and third metal section  108  are made of metal material(s), which generally do not allow electromagnetic waves (e.g., RF waves) to pass through. First metal section  104 , second metal section  106 , and third metal section  108  can be made of any suitable metal or metals. In some embodiments, first metal section  104 , second metal section  106 , and third metal section  108  are made of the same metal material to provide a continuous look and feel to enclosure  102 . In a particular embodiment, first metal section  104 , second metal section  106 , and third metal section  108  are made of an aluminum alloy. 
     First RF transparent region  110  and second RF transparent region  112  are at least partially made of an RF transparent material, which is generally a material that allows at least some of the frequencies within the RF spectrum to pass through. Suitable RF transparent materials can include resins (plastics), glass and/or ceramic. In some embodiments, first RF transparent region  110  and second RF transparent region  112  are made of the same materials to give enclosure  102  a uniform look and feel. In some embodiments, electronic device  100  includes a first antenna positioned proximate to first RF transparent region  110  and a second antenna positioned proximate to second RF transparent region  112 , allowing efficient RF communication to and/or from electronic device  100 . In some embodiments, first metal section  104  and/or third metal section  108  can act as part of the antenna(s) housed within enclosure  102 . Thus, one function of first RF transparent region  110  and second RF transparent region  112  can be to electrically isolate and ground second metal section  106 . 
       FIG. 2  shows a cross section view A-A of enclosure  102 , in accordance with some embodiments. As shown, RF transparent region  110  includes two sections: structural RF transparent section  202  and cosmetic RF transparent section  204 . Structural RF transparent section  202  provides structural support for the coupling of first metal section  104  and second metal section  106 , and therefore can be made of a stiff material such as a stiff resin. Suitable polymer materials can include polyarylether keytone (PAEK) materials (e.g., PEEK, PEK, PEKK) and/or polysulfone materials (e.g., PSU, PPS, PES, PPSU, and PPS), and/or polyester based materials (e.g., PBT, PET). Additionally, polymer materials can also be blends and/or alloys of polymers previously stated. In some embodiments, the resinous materials include fibers, such as glass or ceramic fibers, to increase the strength of structural RF transparent section  202 . The composition of structural RF transparent section  202  can also be chosen to be chemically resistant and retain its geometry when exposed to one or more additional processes subsequent manufacturing processes. For example, resin(s) that do not substantially degrade or deform when exposed to an anodizing process can be used. In some embodiments, the resin(s) do not substantially degrade or deform when exposed to ultraviolet (UV) light (e.g., by exposure to an ultraviolet curing process), chemical coating, computer numerical control (“CNC”) machining, blasting (e.g., sandblasting), and/or polishing. Other factors in determining the material(s) used to form structural RF transparent section  202  include strength sufficient to withstand impact during a drop event of enclosure  102 , moldability of the material(s), and ability to form an external skin that is resistant to exposing internal portions of the polymer material. 
     Cosmetic RF transparent section  204  is situated such that a surface of cosmetic RF transparent section  204  corresponds to exterior surface  201  of enclosure  102 . Thus, exterior surface  201  of enclosure  102  is defined, in part, by surface portions of first metal section  104 , second metal section  106  and cosmetic RF transparent section  204 . Cosmetic RF transparent section  204  can be made of the same material as structural RF transparent section  202  or a different material. In some embodiments cosmetic RF transparent section  204  is made of a material that has more cosmetically or aesthetically appealing properties compared to structural RF transparent section  202 . Thus, cosmetic RF transparent section  204  can be made of a different blend of polymer materials. For example, cosmetic RF transparent section  204  can be made of a uniform, color fade-resistant, and/or dent resistant material. Cosmetic RF transparent section  204  can include a variety of colors, such as red, blue, green, black, white, or a combination thereof. Generally, the color or colors selected provides a desired aesthetic appearance. In some embodiments, cosmetic RF transparent section  204  can also be made of a material that is resistant to degradation and/or deformation when exposed to one or more subsequent processes such as anodizing, UV light exposure, chemical coating, CNC machining, blasting, and/or polishing. Suitable materials for cosmetic RF transparent section  204  can include one or more suitable resinous, ceramic, and/or glass materials. 
     Cosmetic RF transparent section  204  can cover structural RF transparent section  202  such that structural RF transparent section  202  is not visible. That is, cosmetic RF transparent section  204  can prevent structural RF transparent section  202  from defining exterior surface  201  of enclosure  102 . The area of external surface  201  defined by cosmetic RF transparent section  204  can be a gap defined by length  211 . 
     First metal section  104  of enclosure  102  includes extending portion  205 , which can include interlocking feature  207  configured to interlock with corresponding interlocking feature  208  of structural RF transparent section  202 . In some embodiments, structural RF transparent section  202  is molded within enclosure  102  such that material of structural RF transparent section  202  molds within and engages with interlocking feature  207 , forming corresponding interlocking feature  208 . Interlocking features  207  and  208  can be any suitable combination of protrusions and recesses that increase the surface contact area of first metal section  104  and structural RF transparent section  202 , thereby forming a stronger bond or adhesion between first metal section  104  and structural RF transparent section  202 . As shown, structural RF transparent section  202  can include additional interlocking features  209  and  210  that increase the adhesion to second metal section  106  and cosmetic RF transparent section  204 , respectively. 
     Extending portion  205  can allow for good structural integrity and adhesion between first metal section  104  and structural RF transparent section  202 . However, the transmission of RF waves to and/or from antenna  213  through RF transparent section  110  is limit by extending portion  205 . Specifically, extending portion  205  encroaches into the gap defined by length  211  defined by cosmetic RF transparent section  204  and reduces RF transmission to a transmission region defined by length  212 . The transmission region defined by length  212  corresponds to a pathway where RF waves are free to pass. In a particular embodiment, length  211 , which can correspond to a width of cosmetic RF transparent section  204 , is about 2.0 mm and length  212  of the transmission region is about 0.6 mm. To address the limitations that extending portion  205  places on the RF transmission capability of enclosure  102 , modifications can be made to the structure of enclosure  102 . 
       FIG. 3A  shows a cross section view A-A of enclosure  102 , in accordance with another embodiment. In this embodiment, RF transparent region  110  includes three sections: mediating RF transparent section  214 , structural RF transparent section  202  and cosmetic RF transparent section  204 . Mediating RF transparent section  214  can engage with interface surface  203  of first metal section  104 . Interface surface  203  can be within a recess  103  of first metal section  104  to improve engagement between mediating RF transparent section  214  and first metal section  104 . Mediating RF transparent section  214  can include interlock features  215  that engage with corresponding interlock feature  208  of structural RF transparent section  202 . In this way, mediating RF transparent section  214  can be referred to as an anchor. However, since mediating RF transparent section  214  is RF transparent, this increases the area of a transmission region of enclosure  102 . For example, the transmission region can be a gap defined by length  211 . In some cases, length  211  corresponds to a width of cosmetic RF transparent section  204 . In a particular embodiment, mediating RF transparent section  214  increases the transmission region to a length  211  of about 2.0 mm. This increase in the transmission region can correlate with increased performance of antenna  213 . In some cases, the performance of antenna  213  may be good enough that it may be desirable to shorten length  211  in order reduce the relative area of cosmetic RF transparent section  204  with respect to an exterior surface  201  of enclosure  102 . For example, length  211  of cosmetic RF transparent section  204  could potentially be reduced to 0.6 mm. In this way, the addition of mediating RF transparent section  214  can add a functional benefit of improved RF transmission capability and a cosmetic benefit of potentially smaller non-metal exterior surfaces of enclosure  102 . This provides flexibility in designing enclosure  102  while balancing and tuning function and cosmetic aspects. 
     As shown, mediating RF transparent section  214  is engaged with both structural RF transparent section  202  and cosmetic RF transparent section  204 . Cosmetic RF transparent section  204  can cover and prevent structural RF transparent section  202  and mediating RF transparent section  214  from being visible. That is, cosmetic RF transparent section  204  can prevent structural RF transparent section  202  and mediating RF transparent section  214  from defining exterior surface  201  of enclosure  102 . This can be useful when mediating RF transparent section  214  and/or structural RF transparent section  202  are made of material that does not have a desirable aesthetic quality, such as a desired texture, consistency, color or hardness. However, in some embodiments, mediating RF transparent section  214  and/or structural RF transparent section  202  do have desirable aesthetic qualities. Therefore, cosmetic RF transparent section  204  can be an optional member of RF transparent section  110 . In some embodiments, the interfaces between structural RF transparent section  202 , cosmetic RF transparent section  204 , and mediating RF transparent section  214  can be enhanced by re-melting during injection molding processes. These aspects will be described further below with reference to  FIGS. 4A-4E . 
     In some embodiments, methods are employed to increase the adhesion strength between mediating RF transparent section  214  and first metal section  104 . For example, first metal section  104  can be treated prior to molding of mediating RF transparent section  214  to increase the surface area of an interface surface of first metal section  104 . In a particular embodiment, interface surface  203  of first metal section  104  is chemically treated to create a porous interface surface. That is, interface surface  203  can be treated to create numerous small pores  216 . The type of treatment will depend, in part, on the material of first metal section  104 . Suitable chemical treatment for metals such as aluminum or aluminum alloys can include, for example, and acid etching process. Pores  216  can be very small. For example, pores  216  can have an average diameter on a scale of micrometers (micro pores)—that is, smaller than one millimeter. In some embodiments, pores  216  have an average diameter on the scale of nanometers (nano pores)—that is, smaller than one micrometer. Once first metal section  104  is conditioned to have pores  216 , mediating RF transparent section  214  can be molded into pores  216  to create a tightly knit bond between mediating RF transparent section  214  and first metal section  104 . Inset  218  shows a close-up image of pores  216  with material of mediating RF transparent section  214  formed therein. Since pores  216  are very small and the material of mediating RF transparent section  214  fills pores  216 , a tight mechanical interlock is created. 
     Since pores  216  are very small, it may be difficult to completely fill pores  216  with the material of mediating RF transparent section  214 . In some embodiments, flowable material of mediating RF transparent section  214  (e.g., RF transparent in molten form) is molded on first metal section  104  using a high pressure injection molding process such that pores  216  are completely filled or nearly completely filled. Details of such a high pressure injection molding process will be described below further with reference to  FIGS. 4A-4E . 
       FIG. 3B  shows a cross section view A-A of enclosure  102 , in accordance with another embodiment. RF transparent region  110  includes three sections: mediating RF transparent section  214 , structural RF transparent section  202 , and cosmetic RF transparent section  204 . Mediating RF transparent section  214  can engage with interface surface  203  of first metal section  104 , with interface surface  203  positioned within recess  103  of first metal section  104  for improved engagement. Interface surface  203  can include small pores  216  (e.g., micro pores or nano pores) for further increased engagement between mediating RF transparent section  214  and first metal section  104 . Mediating RF transparent section  214  can include interlock features  215  that engage with corresponding interlock feature  208  of structural RF transparent section  202 . In the embodiment of  FIG. 3B , interface surface  303  of second metal section  106 , formed within recess  105  of second metal section  106 , is also treated to have pores  302  (e.g., micro pores and/or nano pores). That is, first metal section  104  can have a first set of pores  216  and second metal section  106  can have a second set of pores  302 . The material of structural RF transparent section  202  is molded within pores  302  of second metal section  106 . 
       FIG. 3C  shows a cross section view A-A of enclosure  102 , in accordance with a further embodiment. In this embodiment, RF transparent region  110  includes two sections: anchor or mediating RF transparent section  214  and cosmetic RF transparent section  204 . Mediating RF transparent section  214  can secure first metal section  104  and second metal section  106 . Cosmetic RF transparent section  204  can cover mediating RF transparent section  214 . Mediating RF transparent section  214  can be formed of a flowable material (e.g., in molten form) incorporated within pores  216  formed within recessed interface surface  203  of first metal section  104  and pores  302  formed within recessed interface surface  303  of second metal section  106 . In other embodiments, only first metal section  104  has pores  216  while second metal section  106  does not have pores  302 . In yet other embodiments, second metal section  106  has pores  302  while first metal section  104  does not have pores  302 . That is, one or both of first metal section  104  and second metal section  106  can have pores  216 / 302  capable of interlocking with RF transparent section  110  that couples mechanically couples first metal section  104  and second metal section  106 . In this way, radio frequency transparent anchor or mediation section  214  defines a radio frequency transmission region of enclosure  102  that includes a gap defined by length  211  between the first metal section  104  and second metal section  106 . 
       FIGS. 4A-4E  show perspective views of enclosure  102  being formed using processes in accordance with some embodiments. At  FIG. 4A , first metal section  104  of enclosure  102  is provided. At this point, first metal section  104  can be in the form of a block or buck since one or more shaping processes can be used to form a final shape of first metal section  104 . First metal section  104  can be made of any suitable material. In some embodiments, first metal section  104  is made of a metal material, such as aluminum or aluminum alloy. 
     At  4 B, recess  103  is formed within first metal section  104 . Recess  103  can define an interface surface  408  for engaging with a molded piece during a subsequent molding process. In some embodiments, interface surface  408  is curved in accordance with a final exterior shape of enclosure  102 . Interface surface  408  can be formed using tool  406 , which can be controlled by a machine, such as a CNC machine. In some embodiments, grooves  410  are formed within interface surface  408 . Grooves  410  can define the portion of interface surface  408  that is molded on during the subsequent molding process. The surface area of interface surface  408  can be increased by forming micro pores and/or nano pores at interface surface  408 . In particular embodiments where first metal section  104  is made of a metal, such as aluminum or aluminum alloy, micro pores and/or nano pores can be formed by an etching process, such as an acid etching process. 
     At  FIG. 4C , mediating RF transparent section  214  is molded on interface surface  408 . That is, the material of RF transparent section  214  while in a flowable state (such as in a molten form from heating) is injection molded onto interface surface  408 . As shown, mediating RF transparent section  214  protrudes from interface surface  408  and can have one or more interlock features  215 . In some embodiments, an injection molding apparatus capable of injecting the flowable material under high pressure such that material of mediating RF transparent section  214  can be fully molded within the pores of interface surface  408 . In some embodiments, pressures in the range of about 30,000 psi are used, with increasing packing pressure (e.g., 35,000 to 40,000 psi) applied as the pores fill. In some embodiments, the pressures are high enough to deform first metal section  104 . However, some deformation may be tolerated since first metal section  104  can undergo a post-injection molding shaping process in order to form a final shape. 
     The gates of the injection molding apparatus can be arranged substantially orthogonal to interface surface  408 , as indicated by arrows  412 . As illustrated in inset  414  showing a cross section close up view at interface surface  408 , pores  206  of first metal section are generally aligned orthogonal to interface surface  408 . Thus, the flow  412  of material orthogonal to interface surface  408  amounts to substantially parallel flow of material with respect to pores  206 . This type of flow can further assure that pores  206  are sufficiently filled to provide extra strength adhesion between first metal section  104  and mediating RF transparent section  214 . In this way, mediating RF transparent section  214  adhered to first metal section  104  can be referred to as a compound structure, with pores  206  acting as an interlock feature of first metal section  104 . It should be noted that this is contrary to conventional processes that would likely avoid direct high pressure injection molding with orthogonal flow of material relative to interface surface  408  since such conditions may bend first metal section  104 . In the methods described herein, however, some bending of first metal section  104  can be tolerated since first metal section  104  can be shaped subsequent to the injection molding process. After the injection molding process is complete, one or more processes can be used to further shape mediating RF transparent section  214 , such as one or more machining, deburring or degating processes. 
       FIG. 4D  shows first metal section  104  positioned next to second metal section  106 . As with first metal section  104 , second metal section  106  at this point can be in the form of a block since subsequent shaping can take place. Structural RF transparent section  202  is then molded on second metal section  106  and mediating RF transparent section  214 , thereby coupling first metal section  104  and second metal section  106 . Structural RF transparent section  202  can engage with interlock features  215  (shown in  FIG. 4C ) of mediating RF transparent section  214 . In some embodiments, the molding process involves partially re-melting the material of mediating RF transparent section  214  such that structural RF transparent section  202  is more firmly adhered to mediating RF transparent section  214 . For example, the molding process can be designed to locally liquefy mediating RF transparent section  214  at reinforcement/bonding points such that the material of structural RF transparent section  202  partially intermingles with the material of mediating RF transparent section  214  during the molding process. In some embodiments, the coupling of first metal section  104  and second metal section  106  is enhanced using ultrasonic welding techniques, laser welding techniques and/or use of adhesive(s). 
     At  FIG. 4E , cosmetic RF transparent section  204  is molded on structural RF transparent section  202  and mediating RF transparent section  214 , and between first metal section  104  and second metal section  106 . In some embodiments, the molding process involves a re-melting process, as described above, that intermingle the material of cosmetic RF transparent section  204  with the material of structural RF transparent section  202  and/or mediating RF transparent section  214 , thereby forming a stronger bond. In addition, first metal section  104  and second metal section  106  are shaped to a final shape. The shaping and/or finishing processes can create a smooth and continuous exterior surface  201  of enclosure  102 . Any suitable shaping process and/or finishing process can be used. For example, one or more machining (e.g., CNC), polishing, blasting and/or anodizing processes can be used. Note that the shaping process can compensate for some, if any, deformation of first metal section  104  and/or second metal section  106  during previous molding processes. An anodizing process can be used to anodize first metal section  104  and second metal section  106 . Thus, if cosmetic RF transparent section  204 , mediating RF transparent section  214  and structural RF transparent section  202  are made of plastic material(s), the plastic material(s) should be resistant to substantial degradation when exposed to the anodizing process. 
     Referring back to  FIG. 1 , it should be noted that the processes described above with respect to coupling first metal section  104 , second metal section  106  with first RF transparent region  110  (including structural RF transparent section  202 , mediating RF transparent section  214 , and cosmetic RF transparent section  204 ) can be used to couple third metal section  108  with second metal section  106  using second RF transparent region  112 . That is, second RF transparent region  112  can include a corresponding structural RF transparent section, mediating RF transparent section, and cosmetic RF transparent section that are arranged similarly to structural RF transparent section  202 , mediating RF transparent section  214 , and cosmetic RF transparent section  204 . 
       FIG. 5  shows flowchart  500  indicating a process for forming an enclosure, in accordance with some embodiments. At  502 , a first metal section of the enclosure is optionally shaped using one or more shaping processes. In some embodiments, the first metal section is made of an aluminum alloy. The optional shaping process can involve creating a general shape that has dimensions roughly close to a final shape of the first metal section. In one embodiment, the shaping process includes forming recesses and engagement features within the first metal section. 
     At  504 , small pores are formed within an interface surface of the first metal section. The pores can be micro pores, meaning an average diameter of the pores is on a scale of micrometers, and/or nano pores, meaning an average diameter of the pores is on a scale nanometers. The pore forming process will depend, in part, on the material of the first metal section. In a particular embodiment where the first metal section is made of aluminum or aluminum alloy, an acid etching process is used. 
     At  506 , a first RF transparent section (e.g., mediating RF transparent section  214 ) is molded on the interface surface of the first metal section. Material of the first RF transparent section is molded within the pores of the first metal section. The material of the first RF transparent section can be chosen such that optimal flow within the pores is achieved. In some embodiments, a high pressure injection molding process is used. Injection molding gates can be positioned to provide substantially parallel flow of the material relative to the pores such that the pores are sufficiently filled to provide good adhesion between the first RF transparent section and the first metal section. In some embodiments, the first RF transparent section includes a fiber composite material having fibers within a resinous base. In some embodiments, the fibers are made of glass. During injection molding process, fibers having small enough dimensions may fit within the pores, while fibers having larger dimensions do not fit within the pores. In some embodiments, the average size of the fibers is chosen to be small enough to fit within the pores. In any case, at least the resinous base material should be injectable within the pores. 
     In addition to choosing a material that provides good flow within the pores, the material of the first section can also be chosen to provide sufficient re-melting during a subsequent molding processes for applying a second RF transparent section and a third RF transparent section. In some embodiments, one or more interlock features are formed on the first RF transparent section, which is configured to interlock with a subsequently molded second RF transparent section. The interlock feature(s) can include one or more protrusion and/or recesses. 
     At  508 , a second RF transparent section (e.g., structural RF transparent section  202 ) is molded on the first RF transparent section and a second metal section. In some embodiments, second RF transparent section is made of the same material as the first RF transparent section. In other embodiments, the second RF transparent section is made of a different material that the first RF transparent section, such as a stiffer resinous material. In some embodiments, the molding process is designed to locally re-melt the material of the first RF transparent section such that a stronger bond is formed between the first RF transparent section and the second RF transparent section. If the first RF transparent section has interlock features, the second RF transparent section can be molded around and/or within the interlock features, forming corresponding interlock features within the second RF transparent section. 
     At  510 , a third RF transparent section (e.g., cosmetic section RF transparent section  204 ) is optionally molded on the first and second RF transparent sections. The third RF transparent section can cover the first and second RF transparent sections such that the first RF transparent section and the second RF transparent section do not form an exterior surface of the enclosure. This can be useful when the first and second RF transparent sections do not have desired cosmetic or aesthetic properties. For example, the first and second RF transparent sections may have good structural integrity but do not have a desired continuous and uniform look and feel. Or the first and second RF transparent sections may not have a desired color and predetermined fade-resistance. In some embodiments, the first RF transparent section, the second RF transparent section and the third RF transparent section are each free of metal material in order to retain good RF transparent properties of the RF transparent region. 
     At  512 , the enclosure is optionally shaped such that an exterior surface of the enclosure has a predetermined shape and/or smoothness. This can involve co-machining the first metal section, second metal section and the third RF transparent section. In addition, the enclosure can be finished using one or more finishing processes such as polishing, blasting, buffing and/or anodizing. It should be noted that additional metal sections of the enclosure can be coupled using additional RF transparent sections. The finished enclosure will have an RF transmission region defined by the RF transparent section(s) and that allows RF waves to pass through. 
     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. 
     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 the specific embodiments described herein are presented for purposes of illustration and description. They are not targeted to be exhaustive or to limit the 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.

Metadata:
Filing Date: 20160302
Publication Date: 20180710
Grant Date: 20180710
Priority Date: 20150501
Inventors: BUSTLE, BENJAMIN SHANE
CATER, TYLER B.
KRASS, DEREK C.
MYERS, SCOTT A.
Assignee: APPLE INC
CPC Classifications: [{"code": "B29L2031/3456", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29L2031/3456", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29C45/14786", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04M1/0202", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29K2101/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29L2031/3481", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29L2031/3437", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29K2101/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29C45/14786", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K5/0243", "inventive": true, "first": true, "tree": "[]"}, {"code": "B29L2031/3437", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29L2031/3481", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29C45/14311", "inventive": true, "first": false, "tree": "[]"}, {"code": "B29C45/14311", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0202", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K5/0247", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0202", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29C45/14786", "inventive": true, "first": true, "tree": "[]"}, {"code": "B29L2031/3481", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29C45/14311", "inventive": true, "first": false, "tree": "[]"}, {"code": "B29L2031/3456", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29K2101/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29L2031/3437", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 57205431