PATENT DOCUMENT

Publication Number: US-7310872-B2
Application Number: US-92878004-A
Country: US
Kind Code: B2

Title: Computer enclosure

Abstract:
A computing device having an improved enclosure arrangement is disclosed. One aspect of the enclosure pertains to enclosure parts that are structurally bonded together to form a singular composite structure. In one embodiment, structural glue is used to bond at least two unique parts together. Another aspect of the enclosure pertains to enclosure parts that are electrically bonded together to form a singular integrated conductive member. In one embodiment, conductive paste is used to bond at least two unique parts together. The improved enclosure is particularly useful in portable computing devices such as laptop computers.

Claims:
1. A method of forming a housing of a consumer electronic product by structurally bonding a first housing member to a second housing member, the housing enclosing internally therein operational components of the consumer electronic product, said method comprising:
 dispensing a glue between the first and second housing members; 
 placing the first housing member in a first fixture; 
 placing the second housing member in a second fixture; 
 clamping the first and second fixtures together so as to sandwich the glue between the first and second housing members; and 
 allowing the glue to cure when the first and second housing members are placed in a predetermined position relative to one another so as to form a singular composite structure. 
 
     
     
       2. The method as recited in  claim 1  wherein the step of dispensing the glue comprises:
 placing the first housing member into a robotically controlled application tool configured for dispensing the glue along a predetermine path; and 
 robotically dispensing the glue on the first member. 
 
     
     
       3. The method as recited in  claim 1  wherein the first fixture is arranged to hold the first member in a fixed position relative to a first reference element of the first fixture, and wherein the second fixture is arranged to hold the second member in a fixed position relative to a second reference element of the second fixture. 
     
     
       4. The method as recited in  claim 3  wherein during placing of the first member a first portion of the first member is arranged to locate flush against a first datum surface of the first fixture, and wherein during placing of the second member a second portion of the second member is arranged to locate flush against a datum second surface of the second fixture. 
     
     
       5. The method as recited in  claim 3  wherein the first and second fixtures are arranged to mate with each another so as to locate the first portion of the first member relative to the second portion of the second member. 
     
     
       6. The method as recited in  claim 3  wherein the first and second fixtures place the first portion substantially flush with the second portion. 
     
     
       7. The method as recited in  claim 3  wherein the first and second fixtures place the first portion in a predetermined offset position relative to the second portion. 
     
     
       8. A method as recited in  claim 1 , wherein the first and second members are arranged to form a gap for the placement of the glue. 
     
     
       9. The method as recited in  claim 8  wherein the glue is arranged to absorb geometric variations found in the first and second members so as to meet a predetermined geometry of the single composite structure. 
     
     
       10. A method as recited in  claim 1 , wherein the first member is formed from a first material, and wherein the second member is formed from a second material that is different than the first material. 
     
     
       11. The method as recited in  claim 1  wherein the glue is a two part epoxy. 
     
     
       12. The method as recited in  claim 1  wherein the consumer electronic product is a computing device. 
     
     
       13. The method as recited in  claim 12  wherein the computing device is a portable computer including a base and a lid, and wherein the first and second housing members work together to form at least a portion of the housing of the base or at least a portion of the housing of the lid. 
     
     
       14. The method as recited in  claim 10  wherein the first member is formed from a plastic material, and wherein the second member is formed from a metallic material. 
     
     
       15. The method as recited in  claim 14  wherein the first member is formed from carbon fiber, and the second structural member is formed from titanium. 
     
     
       16. A method of forming a housing of a consumer electronic product by electrically bonding a first housing member to a second housing members the first and second housing members enclosing internally therein operational components of the consumer electronic product, said method comprising:
 dispensing a conductive paste onto a first conductive surface of the first housing member, the conductive paste being a metal filled electrically conductive ink; 
 flowing the conductive paste from the first conductive surface of the first housing member to a second conductive surface of the second housing member; and 
 allowing the conductive paste to cure so as to electrically seal an interface between the first and second conductive surfaces of the first and second housing members. 
 
     
     
       17. The method as recited in  claim 16  wherein the conductive paste is dispensed along a predetermined path that corresponds to the area of desired electrical contact between the first and second housing members. 
     
     
       18. The method as recited in  claim 16  wherein gravity is used to flow the conductive paste from the first conductive surface of the first member to the second conductive surface of the second member. 
     
     
       19. The method as recited in  claim 16  wherein the first housing member is formed from a first material, and wherein the second housing member is formed from a second material that is different than the first material. 
     
     
       20. The method as recited in  claim 19  wherein the first housing member is formed from a conductive material, wherein the second housing member is formed from a non-conductive material that is selectively coated with a conductive layer, and wherein the conductive paste electrically connects and electrically seals an interface between the conductive material of the first housing member and the conductive layer of the second housing member. 
     
     
       21. The method as recited in  claim 16  wherein the step of dispensing is implemented in a robotically controlled application tool. 
     
     
       22. The method as recited in  claim 16  wherein the first housing member is formed from a first metallic material, wherein the second housing member is formed from a plastic material, and wherein the conductive layer is formed from a second metallic material. 
     
     
       23. The method as recited in  claim 22  wherein the plastic material is a carbon fiber plastic, the second metallic material is a nickel plated layer, and the metallic material is titanium sheet metal. 
     
     
       24. The method as recited in  claim 16  wherein the metal filled electrically conductive ink is a nickel filled electrically conductive ink. 
     
     
       25. The method as recited in  claim 24  wherein the nickel filled electrically conductive ink has viscosity between about 5000 centipoise to about 10000 centipoise. 
     
     
       26. The method as recited in  claim 16  further comprising:
 selectively coating the interior surface of at least one of the housing members with a conductive material in order to form the conductive surface of the housing member, the conductive material being configured for shielding electronic emissions. 
 
     
     
       27. The method as recited in  claim 26  wherein the step of selectively coating is performed via a plating, painting or deposition process. 
     
     
       28. The method as recited in  claim 16  wherein the consumer electronic product is a computing device. 
     
     
       29. The method as recited in  claim 28  wherein the computing device is a portable computer including a base and a lid, and wherein the first and second housing members work together to form at least a portion of the housing of the base or at least a portion of the housing of the lid.

Description:
RELATED APPLICATIONS 
     This application is a divisional of prior U.S. application Ser. No. 09/821,784, entitled “COMPUTER ENCLOSURE”, filed on Mar. 28, 2001 now U.S. Pat. No. 7,012,189, which is herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to a computer device. More particularly, the present invention relates to enclosures for use in a computer device. 
     In recent years portable computers have become thin, light and powerful. One factor contributing to this phenomena is in the manufacturer&#39;s ability to fabricate various components of the computer in smaller and smaller sizes while in most cases increasing the power and or operating speed of such components. 
     The trend of thinner, lighter and powerful presents a continuing design challenge in the design of some components associated with the portable computer. For example, one design challenge associated with the portable computer is the design of the enclosures used to house the various internal components of the portable computer. This design challenge generally arises from two conflicting design goals—the desirability of making the enclosure lighter and thinner, and the desirability of making the enclosure stronger and more rigid. In most portable computers, the enclosures are mechanical assemblies having parts that are screwed, riveted, snapped or otherwise fastened together at discrete points. The lighter enclosures, which use thinner plastic structures and less fasteners, tend to be more flexible and therefore they have a greater propensity to buckle and bow when used while the stronger and more rigid enclosures, which use thicker plastic structures and more fasteners, tend to be thicker and carry more weight. Unfortunately, increased weight may lead to user dissatisfaction, and bowing may damage the internal parts of the portable computer. 
     Furthermore, as the power and sophistication of integrated circuit devices have increased, so has the level of electromagnetic interference generated by such devices, i.e., integrated circuit devices unintentionally emit electromagnetic radiation during operation that may cause interference with communication devices, such as telephones, radios, and televisions. In order to prevent interference, the enclosures are often shielded with an electrically conductive material to block the emission of electromagnetic radiation, which is emanating from the integrated circuit devices. By way of example, some methods for shielding the enclosure include: lining the plastic enclosure with a metallic foil such as aluminum, lining the plastic enclosure with sheet metal such as steel, and coating the inner surfaces of the plastic enclosure with a metallic material such as nickel or copper. Additionally, silicone based electrically conductive EMI gaskets may be formed in place between two parts of the enclosure before an enclosure is assembled. Such electrically conductive EMI gaskets are commonly known as Form-In-Place. As is generally well known, form-in-place gaskets must be compressed up to 40% in order to achieve an enclosure capable of containing electronic emissions. 
     Although current enclosure designs work well, in many instances it would be desirable to provide enclosures that are thinner, lighter, stronger and aesthetically more pleasing than current enclosure designs. 
     SUMMARY OF THE INVENTION 
     The invention relates, in one embodiment, to a computing device. The computing device includes a first member having a first structural element and a first conductive element. The computing device further includes a second member having a second structural element and a second conductive element. The computing device additionally includes a means for electrically and structurally coupling the elements of the first and second members together. 
     The invention relates, in another embodiment, to a component of a computer enclosure. The component includes a first structural member and a second structural member. The component further includes an adhesive disposed between the first and second members, the adhesive structurally attaching the first and second members to form a singular composite structure. 
     The invention relates, in another embodiment, to a component of a computer enclosure. The component includes a first member having a first conductive surface. The component further includes a second member having a second conductive surface. The component additionally includes a conductive bridge electrically connecting the first and second conductive surfaces and electrically sealing an interface between the first and second conductive surfaces so as to form a singular conductive structure for shielding electronic emissions. 
     The invention relates, in another embodiment, to a portable computer enclosure. The portable computer enclosure includes a first case configured to at least partially enclose internal components of the portable computer. The first case includes a first member formed from a first material and a second member formed from a second material that is different than the first material. The first member is structurally glued to the second member to form a first composite structure. The glue has properties that allow it to compensate for tolerances in the first and second members so as to produce a desired first case dimension. 
     The invention relates, in another embodiment, to a method of forming a computer enclosure. The method includes providing a casing and a frame. The method further includes structurally bonding the frame to the casing via glue. The method additionally includes electrically bonding the frame to the casing via a conductive paste. 
     The invention relates, in another embodiment, to a method of forming a computer enclosure by structurally bonding a first member to a second member. The method includes dispensing a glue between the first and second members. The method further includes applying a force to sandwich the glue between the first and second members. The method additionally includes allowing the glue to cure when the first and second members are placed in a predetermined position relative to one another so as to form a singular composite structure. 
     The invention relates, in another embodiment, to a method of forming a computer enclosure by electrically bonding a first member to a second member. The method includes dispensing a conductive paste on a first conductive surface of the first or second member. The method further includes flowing the conductive paste from the first conductive surface of the first or second member to a second conductive surface of the first or second member. The method additionally includes allowing the conductive paste to cure so as to electrically seal an interface between the first and second conductive surfaces of the first or second member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a perspective diagram of a portable computer, in accordance with one embodiment of the present invention. 
         FIG. 2  is a broken away perspective diagram of a base of the portable computer of  FIG. 1 , in accordance with one embodiment of the present invention. 
         FIG. 3  is a broken away perspective diagram of a top casing of the base of  FIG. 2 , in accordance with one embodiment of the present invention. 
         FIG. 4  is a broken away perspective diagram of a bottom casing of the base of  FIG. 2 , in accordance with one embodiment of the present invention. 
         FIG. 5  is a top inside view of the top casing of  FIG. 3 , in accordance with one embodiment of the present invention. 
         FIG. 6  is a side view, in cross section, of the top casing of  FIG. 5  (taken along line  6 – 6 ′), in accordance with one embodiment of the present invention. 
         FIG. 7  is a top inside view of the bottom casing of  FIG. 4 , in accordance with one embodiment of the present invention. 
         FIG. 8  is a side view, in cross section, of the top casing of  FIG. 7  (taken along line  8 – 8 ′), in accordance with one embodiment of the present invention. 
         FIG. 9  is a flow diagram showing a method of constructing an enclosure, in accordance with one embodiment of the present invention. 
         FIG. 10  is a flow diagram showing a method for structurally bonding a frame to a casing, in accordance with one embodiment of the present invention. 
         FIGS. 11A–C  are side views, in cross section, showing one method of structurally coupling a frame to a casing, in accordance with one embodiment of the present invention. 
         FIG. 12  is a flow diagram showing a method for structurally bonding a frame to a casing, in accordance with one embodiment of the present invention. 
         FIG. 13  is a flow diagram showing a method for electrically bonding a frame to a casing, in accordance with one embodiment of the present invention. 
         FIG. 14A–D  are side views, in cross section, showing one method of electrically coupling a frame to a casing, in accordance with one embodiment of the present invention. 
         FIG. 15  is a block diagram of a conductive paste applicator tool, in accordance with one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention generally pertains to a computing device. More particularly, the invention pertains to an improved enclosure arrangement for use in the computing device. One aspect of the invention pertains to an enclosure having at least two unique parts that are structurally bonded together to form a singular composite structure. In one embodiment, structural glue is used to bond the two unique parts together. Another aspect of the invention pertains to an enclosure having at least two unique parts that are electrically bonded together to form a singular integrated conductive member. In one embodiment, conductive paste is used to bond the two unique parts together. The invention is particularly useful in portable computing devices such as laptop computers. 
     Embodiments of the invention are discussed below with reference to  FIGS. 1–15 . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes as the invention extends beyond these limited embodiments. 
       FIG. 1  is a perspective diagram of a portable computer  100 , in accordance with one embodiment of the invention. The portable computer  100  generally includes a base  102  and a lid  104 . The base  102  is configured to enclose various integrated circuit chips and other circuitry that provide computing operations for the portable computer  100 . By way of example, the integrated circuit chips and other circuitry may include a microprocessor, Read-Only Memory (ROM), Random-Access Memory (RAM), a disk drive, a battery, and various input/output support devices. The base  102  is also configured to enclose various structural members for supporting the base  102 . For example, the structural members may include ribs, bars, frames and the like. The internal components of the base  102  are generally surrounded at a peripheral region by a top case  124  and a bottom case  126  that serve to support the internal components in their assembled position within the base  102 . In some instances, the integrated circuit chips and other circuitry may generate unwanted electrical emissions (EMI), and therefore, the base  102 , and more particularly the top and bottom cases  124  and  126 , is also configured to contain electronic emissions therein. This will be described in greater detail below. 
     The base  102  is also arranged to hold a plurality of input devices such as a keyboard  106 , a track pad  108  and button(s)  110 . The keyboard  106 , which includes a plurality of keys, allows a user of the portable computer  100  to enter alphanumeric data. The track pad  108  allows a user to move an input pointer on a graphical user interface. Button(s)  110  allows a user to make a selection on the graphical user interface. As shown, the track pad  108  and button(s)  110  are located in a front portion (or palm rest) of the base  102 , and the keyboard  106  is located in a back portion of the base  102 . 
     In one embodiment, the keyboard  106  is arranged to be a modular unit that is movable relative to the base  102 . That is, the keyboard  106  is movable such that it can be coupled to and/or de-coupled from the base  102 . In one implementation, the movable keyboard is arranged to act as a trap door that covers an opening in the base. The opening allows user access to various internal components enclosed inside the base. As such, the keyboard  106  is adapted to move between a mounting condition, which secures the keyboard to the base and which prevents access through the opening, and a removal condition, which enables removal of the keyboard from the base and which allows access through the opening. By way of example, a movable keyboard system, which may be used in the portable computer  100 , may be found in U.S. patent application Ser. No. 09/405,552, filed on Sep. 24, 1999, and U.S. patent application Ser. No. 09/755,625, filed on Jan. 4, 2001, both of which are herein incorporated by reference. 
     The lid  104  is pivotally coupled to the base  102  via a hinge mechanism  112 . As such, the lid  104  may rotate into an open position (as shown) or a closed position (not shown) relative to the base  102 . The lid  104  generally contains a liquid crystal display (LCD)  114  that is used to display the graphical user interface (including perhaps a pointer or cursor) as well as other information to the user. The LCD display  114  is generally surrounded at a peripheral region by a bezel  116  that serves to support the LCD display  114  in its assembled position within the lid  104 . The bezel may also serve to reduce electronic emissions emanating from within the lid  102 . As should be appreciated, the input devices  106 – 110  and LCD display  114  are visible to a user of the portable computer  100  when the lid  104  is in the open position and no longer visible to the user when the lid  104  is in a closed position., i.e., the base and lid are substantially flush with one another. 
     A locking mechanism  120  is also provided for securing the lid  104  to the base  102  when the lid  104  is in the closed position. The locking mechanism  120  generally consists of two parts, a base side locking mechanism  120 A and a lid side locking mechanism  120 B. As shown, the base side locking mechanism  120 A is located in the front portion  102 A of the base  102  (in front of the track pad  108 ) and the lid side locking mechanism  120 B is located in a top portion  116 A of the bezel  116 . Furthermore, the base side locking mechanism  120 A and the lid side locking mechanism  120 B are cooperatively positioned so that when the lid  104  is closed, the locking mechanisms  120  lockably engage with one another thus securing the lid  104  to the base  102 . The locking mechanism  120  also includes a knob or switch  122  for releasing the base side locking mechanism  120 A from the lid side locking mechanism  120 B (or vice versa) so as to allow the lid  104  to be opened. By way of example, a locking mechanism, which may be used in the portable computer  100 , may be found in U.S. patent application Ser. No. 09/755,622, filed on Jan. 5, 2001, which is herein incorporated by reference. 
       FIG. 2  is a broken away perspective diagram of the top case  124  and the bottom case  126 , in accordance with one embodiment of the present invention. The enclosed components of the base  102  are not shown in  FIG. 2  to simplify discussion. The top case  124  and the bottom case  126  are configured to electrically and mechanically couple to one another to form the base  102  so as to enclose the various integrated circuit chips and other circuitry that provide computing operations for the portable computer  100 . For example,  FIG. 1  shows the base  102  in its assembled condition, i.e., the top and bottom cases  124 ,  126  are connected, and  FIG. 2  shows the base  102  in its un-assembled condition, i.e., the top and bottom cases  124 ,  126  are disconnected. The top and bottom cases  124 ,  126  are generally adapted for engagement and coupled to one another via a fastening device. In the illustrated embodiment, the peripheral bottom edges  128  of the top case  124  are adapted to engage the peripheral top edges  130  of the bottom case  126 , and a plurality of screws  136  are used to hold the two cases  124 ,  126  together when the peripheral edges  128 ,  130  are engaged. In addition, the inner surfaces  132 ,  134  of the top case  124  and bottom case  126  may be formed from a conductive material so as to reduce transmissions of electronic emissions into and out of the base  102 . In most cases, the conductive inner surfaces  132 ,  134  of the top case and bottom cases  124 ,  126  electrically couple to one another through peripheral edges  128  and  130 . 
     To elaborate further, the peripheral edges  128  of the top case  124  generally include angled retention hooks  138 , and the peripheral edges  130  of the bottom case  126  generally include angled retention slots  140 . The angle of the hooks and slots generally correspond with one another. As shown, the retention hooks  138  are positioned along opposing side peripheral edges  128 ′ of the top case  124 , and the retention slots  140  are positioned along opposing side edges  130 ′ of the bottom case  126 . The angled retention hooks  138  are typically angled towards the front of the top case  124  while the angled retention slots are typically angled towards the rear of the bottom case  126 . As such, the angled retention hooks  138  are configured to slide into the angled retention slots  140  thus securing the peripheral edges  128 ′ and  130 ′ together, i.e., the hooks and slots are inversely similar. As should be appreciated, the angled feature of the hooks and slots provides greater strength, i.e., in two coordinates, than a non-angled feature. However, it should be noted, that this is not a limitation and that the design of the hooks and slots may vary according to the specific design of each case. 
     The top case  124  also includes a plurality of recessed lips  146  that are positioned along a front peripheral edge  128 ″ of the top case  124 . The plurality of recessed lips  146  are configured to engage a front portion  150  of the bottom case  126  when the retention hooks  138  are slid into the retention slots  140  of the bottom case  126  so as to secure the front edges  128 ″ and  130 ″ of the top and bottom cases  124 ,  126  together. As should be appreciated, the hooks, slots and lips work together to hold the two cases in place while the screws (when engaged) are arranged to hold the cases together and to prevent the hooks and lips from sliding out. 
     Additionally, the top case  124  generally includes a top plate  152  with a top frame  154  attached thereto, and the bottom case  126  generally includes a bottom plate  156  with a bottom chassis  158  attached thereto. The top frame  154  and the bottom chassis  158  are arranged to structurally support the periphery of the top and bottom plates  152 ,  156 , respectively. In one embodiment, an adhesive is used to structurally attach the top frame  154  to the top plate  152  and to structurally attach the bottom chassis  158  to the bottom plate  156 . In another embodiment, a conductive paste is used to electrically bond the top frame  154  to the top plate  152  and to electrically bond the bottom chassis  158  to the bottom plate  156 . These two embodiments will be described in greater detail below. As shown, the top plate  152 , top frame  154  and bottom plate  156 , provide a shell for enclosing the internal components. For example, the top frame  154  and bottom plate  156  provide walls for surrounding the internal components, and the top plate  152  and bottom plate  156  provide surfaces for covering the internal components. 
     Although not shown in  FIG. 2 , the base  102  may enclose an inner frame for helping support the inner regions of the base  102 . The inner frame generally includes a plurality of ribs that are attached to the top frame  154  and/or the bottom chassis  158  and that extend in multiple directions therefrom. The internal components such as the microprocessor, Read-Only Memory (ROM), Random-Access Memory (RAM), disk drives, battery, and various input/output support devices are typically placed within open areas formed between the plurality of ribs. 
       FIG. 3  is a broken away perspective diagram of the top plate  152  and the top frame  154 , in accordance with one embodiment of the present invention. As shown, the top plate  152  is configured for placement within the top frame  154 . The top frame  154  includes a plate opening  160  for receiving a raised portion  162  of the top plate  152 , and a flange portion  164  for receiving a first recessed portion  166  of the top plate  152 . For example, the shape of the plate opening  160  typically coincides with the shape of the raised portion  162 . In one embodiment, the opening  160  has an inner peripheral surface  161  that is configured to substantially mate with an outer peripheral surface  163  of the raised portion  162  when the raised portion  162  is placed within the opening  160 . In another embodiment, a top surface  168  of the top plate  152  is configured to be flush with a top surface  170  of the top frame  154  when the raised portion  162  of the top plate  152  is placed within the plate opening  160  of the top frame  154  (as shown in  FIGS. 1 &amp; 2 ). 
     The top frame  154  also includes a wall portion  172  that extends below the flange portion  164 . As shown, the outer periphery  173  of the wall portion  172  makes up a portion of the exterior of the base  102  while the inner periphery  174  of the wall portion  172  is configured to surround the outer periphery  176  of the recessed portion  166  when the top plate  152  is placed within the top frame  154 . In the illustrated embodiment, the retention hooks  138  and lips  146  extend from the peripheral bottom edge  128  of the wall portion  172 . 
     Further, the wall portion  172  includes various openings for providing access to components of the portable computer  100 . For example, a front side  178  of the top frame  130  includes a switch opening  180  for allowing access to the switch  122 , and a drive opening  182  for allowing access to a disk drive such as a floppy, zip, CD or DVD drive. Further still, the raised portion  162  includes a keyboard opening  184  and a track pad opening  186 . The keyboard opening  184  is adapted for receiving the keyboard  106 , and the track pad opening  186  is adapted for receiving the track pad  108  and button(s)  110 . The top plate  152  also includes a second recess portion  188  for supporting a bottom edge of the keyboard  106  when the keyboard  106  is placed within the opening  184 . As shown, the second recess portion  188  extends into the opening  184  past the inner periphery  185  of the opening  184 . In most situations, the keyboard opening  184  is arranged to allow access to various internal components of the portable computer  100  when the keyboard  106  is moved away from the opening  184 . By way of example, the opening  184  may allow an operator of the portable computer  100  to upgrade internal components such as a modem, memory, hard drive and/or the like. 
     Referring to  FIGS. 5 &amp; 6 , the top case  124  will be described in greater detail.  FIG. 5  is a top inside view of the top case  124 , in accordance with one embodiment of the present invention, and  FIG. 6  is a side elevation view, in cross section of the top case  124  including the top plate  152  and the top frame  154 , in accordance with one embodiment of the present invention. In the illustrated embodiments, the top plate  152  is formed from a suitable shielding material such as sheet metal. By way of example, 0.4 mm thick Titanium sheet metal may be used. Titanium sheet metal provides great shielding while increasing rigidity and reducing the weight of the portable computer  100  (e.g., Titanium is stronger than steel, but lighter than Aluminum). 
     In addition, the top frame  154  is formed from a suitable plastic, and the inner surfaces are selectively coated with a conductive layer  190 . The conductive layer  190  is typically arranged to provide shielding for electronic emissions. By way of example, the top frame  154  may be formed from a carbon fiber and the inner surfaces of the top frame  154  may be selectively plated with a Nickel or Nickel-Copper material having a thickness of approximately 1 micrometer. In most cases, the conductive layer  190  is disposed around the inner periphery  174  of the wall  172  and a segment  192  of the flange portion  164  (as shown in  FIG. 6 ). It should be noted, however, that this is not a limitation and that the coverage of the conductive layer may vary according to the specific needs of each enclosure. Furthermore, as shown, the conductive layer  190  may be disposed over the peripheral edges  128  and over the angled retention hooks  138  extending from the peripheral bottom edges  128  of the wall  172 . 
     It should be noted that the above elements are not a limitation and that they may vary according to the specific needs of each enclosure. For example, steel sheet metal may be used to form the top plate, and the top frame may be formed from other materials including plated plastic or metal. Moreover, the conductive layer may be applied by coating, painting, depositing and/or the like. Additionally, the conductive layer may be formed from other suitable materials or coatings such as silver or copper paint. As should be appreciated, the thickness of the conductive layer may vary (larger or smaller) according to the type of material used and the method for applying the material. 
     In accordance with one aspect of the invention, a structural adhesive  200  is used to structurally attach the top frame  154  to the top plate  152  (as shown in  FIG. 6 ). The structural adhesive  200  is configured to exhibit good strength characteristics and good adhesion between the top frame  154  and the top plate  152 . The structural adhesive  200  is also configured to reduce tolerance variability in the overall geometry of the top case  124 . The adhesive generally has both a compliant state and a binding state. The binding nature of the adhesive  200  is arranged to form a singular composite structure between two disparate parts (e.g., metal top plate and plastic top frame) that is stronger than conventional fastening methods, i.e., bolts, screws, snaps, and inserts. The compliant nature of the adhesive  200  is arranged to absorb geometric variations of the two disparate parts (e.g., metal top plate and plastic top frame) so as to form a singular composite structure with an overall geometry that is desirable. 
     As shown in  FIG. 6 , the structural adhesive  200  is disposed between the flange portion  164  of the top frame  154  and the recessed portion  166  of the top plate  152 . More particularly, the structural adhesive  200  is disposed between an exposed segment  202  of the flange portion  164 , and an exposed segment  204  of the recessed portion  166 . By exposed, it is meant that the surface is a non-coated surface. For example, the exposed segment  202  generally corresponds to the plastic surface rather than the conductive layer  190 . As should be appreciated, this is done to ensure a good bond between the adhesive  200  and the top frame  154 . For instance, the bond between the adhesive and the plastic is typically greater than the bond between the conductive layer and the plastic. 
     In most cases, the flanged portion  164  and the recessed portion  166  are arranged to form a gap G therebetween for the placement of the adhesive  200 . The gap G is generally disposed between the exposed segment  202  and the exposed segment  204 . In the illustrated embodiment, the size of the gap G is defined by a length L of the recessed portion  166  (from the top surface  168  to the surface  204 ) and a thickness T of the flanged portion  164  when the top surface  168  of the top plate  152  is flush with the top surface  170  of the top frame  154 . In most cases, flush surfaces are desired to produce a substantially planar surface along the outer peripheral surface of the top case  124 . This is considered to be a geometric tolerance of the top case  124 . 
     As should be appreciated, the geometric tolerances of the top case  124  must be predictable to meet production yield standards. The top frame  154  and top plate  152  are typically manufactured using very different processes (e.g., molded plastic and formed sheet metal) representing very different tolerances. Unfortunately, the tolerances of the top frame  154  and the top plate  152  may stack thus forming a final assembly (e.g., top case  124 ) that doesn&#39;t meet standards. By way of example, tolerance stacking may lead to an overall thickness that is too large or too small or to adjacent surfaces that do not align properly with one another, i.e., parts that don&#39;t fit together or parts that create undesirable surfaces such as lips. Referring to  FIG. 6 , if the length L is too large and/or if the thickness T is too small then a non-flush surface between the top surface  168  of the top plate  152  and the top surface  170  of the top frame  154  may be encountered, i.e., a lip may be formed. 
     Accordingly, the adhesive  200  is arranged to absorb geometric variations that may influence a parts position relative to another parts position. That is, the structural adhesive  200  is configured to be compliant so as to conform to the width of the gap G even when the tolerances of the parts are at a maximum or minimum. By way of example, variations in the parts may lead to a gap size of between 0.2 and 0.6 mm. In the illustrated embodiment, the width of the compliant adhesive  200  is configured to adjust with the width of the gap G to place the top surface  168  of the top plate  152  flush with the top surface  170  of the top frame  154 . For example, the compliant adhesive  200  is arranged to conform to a larger gap G when the length L is at a maximum tolerance and/or when the thickness T is at a minimum tolerance. In addition, the compliant adhesive  200  is arranged to conform to a smaller gap G when the length L is at a minimum tolerance and/or when the thickness T is at a maximum tolerance. In this way there is no tolerance stacking. That is, slight geometry variations in one part will have no influence on an adjacent parts position in the assembly. 
     In one embodiment, the compliant structural adhesive  200  is a glue that is compliant when dispensed and then cures to a rigid structure over time. In particular, the glue transforms between a liquid state, exhibiting its compliant attributes, and a solid state, exhibiting its structural attributes. In the liquid state, the glue exhibits a readiness to flow and a relatively high incompressibility that allows it to fill the gap (whether small or large). In the solid state, the glue exhibits rigidity and a relatively high resistance to movement that allows it to maintain the width of gap chosen during the liquid state, and to form a singular composite structure. By way of example, the glue may be applied between the top frame  154  and the top plate  152  in bead form (liquid state), and after a set time, the glue may harden thus forming a rigid structure that attaches the top frame  154  to the top plate  152  (solid state). Generally speaking, the adhesive offers a dynamic way to place multiple parts in desired positions relative to one another and a static way to fix the multiple parts together. In one implementation, the glue is a two-part catalytic epoxy that forms a strong structural bond between the plastic top frame and the metal top plate. By way of example, 201/19 epoxy produced by Lord Co. of Erie, Pa., may be used to structurally attach the carbon fiber top frame to the titanium top plate. 
     In accordance with another aspect of the invention, a conductive bridge  210  is used to electrically connect the top frame  154  to the top plate  152 . In the illustrated embodiment, the conductive bridge  210  is electrically bonded to a portion of the conductive layer  190  and to a portion of the top plate  152 . The binding nature of the conductive bridge  210  is arranged to form a singular electrical structure, including the conductive layer  190  and the top plate  152 , for shielding the top case  124  from electronic emissions. In most cases, the conductive bridge  210  is arranged to seal a gap  212  formed between the recessed portion  166  of the top plate  152  and the conductive layer  190  of the top frame  154 , i.e., the conductive bridge  210  is disposed in the gap  212 . As should be appreciated, without the conductive bridge  210 , the gap  212  typically provides an electrical opening where radiation and/or electronic emissions may escape. In general, the conductive bridge  210  provides a better electrical flow therethrough than could be obtained through the top plate  152  and conductive surface  190  directly. 
     The conductive bridge  210  is generally formed from a suitable conductive material. In a preferred embodiment, the conductive bridge is formed from a conductive paste that exhibits good electrical characteristics and good adhesion between the conductive layer  190  and the top plate  152 . The conductive paste generally has two states—a liquid state and a solid state. In most cases, the conductive paste is applied in its liquid state (between the top plate and the top frame) and after a set time it changes to its solid state, i.e., the conductive paste is rigidly set over time, thus forming the electrically integrated structure. For example, the conductive bridge  210  may be formed by dispensing a conductive paste in bead form over the edge of the recessed portion  166  of the top plate  152  and allowing the bead to flow over the side of the recessed portion and over the segmented portion  192  of the conductive layer  190  of the top frame  154  via gravity. 
     In one embodiment, the conductive paste is a metal filled electrically conductive ink that forms a strong electrical bond between the plated top frame and the metal top plate. In general, the electrically conductive ink is a solvent-based material that includes a metal filler and a carrier medium for carrying the metal filler. In most cases, the carrier medium is acetate. During several experiments, it was found that a nickel filled electrically conductive ink formed an exceptionally strong electrically bond between the Nickel-Copper plated conductive layer  190  and the titanium top plate  152 . It is generally believed that the strong electrical bond is created because of the ability of the nickel to overcome oxidation problems that may be found on the surface of the titanium top plate, i.e., the nickel base conductive ink eats through the oxidation. It was also found that a nickel filled electrically conductive ink having a viscosity of between about 5,000 centipoise to about 10,000 centipoise, and more particularly about 7,500 centipoise works well. Furthermore, Nickel filled electrically conductive ink provides a good balance of low cost and high conductivity. In one embodiment, a nickel filled electrically conductive ink (part no. EE 40-3917) produced by Epoxies, Etc. of Cranston, R.I., may be used. In some implementations, it may desirable to modify the conductive ink (EE 40-3917), which has a viscosity of 14,000 centipoise, to maintain the viscosity mentioned above. For example, an acetate solution may be added to EE 40-3917 to produce a viscosity of between about 5,000 centipoise to about 10,000 centipoise, and more particularly about 7,500 centipoise. 
       FIG. 4  is a broken away perspective diagram of the bottom plate  156  and the bottom chassis  158 , in accordance with one embodiment of the present invention. As shown, the bottom chassis  158  is configured for placement within the bottom plate  156 . The bottom plate  156  includes a bottom surface  220  and a bottom plate wall  222  extending upwards therefrom. The bottom surface  220  is arranged for receiving a flange portion  224  of the bottom chassis  158 , and the bottom plate wall  222  is arranged for receiving a bottom chassis wall  226  extending upwards from the flange portion  224 . The outer periphery  228  of the bottom chassis wall  226  is arranged to substantially coincide with the inner periphery  230  of the bottom plate wall  222 . In the illustrated embodiment, the retention slots  140  are positioned on the peripheral top edge  130  of the bottom chassis wall  226 . Furthermore, a top surface  225  of the bottom plate wall  222  is configured to extend above the peripheral edge  130  of the bottom chassis wall  226  when the bottom chassis  158  is attached to the bottom plate  156 . This extended distance is generally referred to as the predetermined offset position O. The predetermined offset position O will be described in greater detail below. 
     Further, both the bottom plate wall  222  and the bottom chassis wall  226  are arranged to cooperate with the wall portion  172  of the top frame  154  so as to form a box like structure (e.g., base) when the top case  124  and bottom case  126  are fastened together. For example, the top surface (e.g., peripheral edge  130 ) of the bottom chassis wall  226  is configured to engage the peripheral edge  128  of the top frame wall  172 , and the bottom plate wall  222  is configured to surround the outer periphery  173  of the top frame wall  172 . In most cases, the top frame  154  includes a recessed edge for receiving the extended portion of the bottom plate wall  222  so that the outer peripheral surface of the top frame wall  172  is flush with the outer peripheral surface of the bottom plate wall  222  when connected. 
     Further still, the bottom plate  156  includes various openings for providing access to various components of the portable computer  100 . For example, the bottom surface  220  of the bottom plate  156  includes a battery opening  232  for allowing access to a battery (not shown) housed within the base  102 , and a plurality of through holes  234  for allowing the passage of screws  136 . Further still, the bottom chassis  158  includes various extensions for providing support to the bottom plate  156 . For example, the bottom chassis  158  includes a rib  236 , which generally extends from the flange portion  224 , for surrounding the battery opening  232 . 
     Referring to  FIGS. 7 &amp; 8 , the bottom case  126  will be described in greater detail.  FIG. 7  is a top inside view of the bottom case  126 , in accordance with one embodiment of the present invention, and  FIG. 8  is a side elevation view, in cross section of the bottom case  126  including the bottom plate  156  and the bottom chassis  158 , in accordance with one embodiment of the present invention. In the illustrated embodiments, the bottom plate  156  is formed from a suitable shielding material such as sheet metal. By way of example, 0.4 mm thick Titanium sheet metal may be used. Titanium sheet metal provides great shielding while increasing rigidity and reducing the weight of the portable computer  100  (e.g., Titanium is stronger than steel, but lighter than Aluminum). 
     In addition, the bottom chassis  158  is formed from a suitable plastic, and the inner surfaces are selectively coated with a conductive layer  240 . The conductive layer  240  is typically arranged to provide shielding for electronic emissions. By way of example, the bottom chassis  158  may be formed from a carbon fiber and the inner surfaces of the bottom chassis  158  may be selectively plated with a Nickel or Nickel-Copper material having a thickness of approximately 1 micrometer. In most cases, the conductive layer  240  is disposed around the inner periphery of the bottom chassis wall  226  and the flange portion  224  (as shown in  FIG. 8 ). It should be noted, however, that this is not a limitation and that the coverage of the conductive layer may vary according to the specific needs of each enclosure. Furthermore, as shown, the conductive layer  240  may be disposed over the peripheral edges  130  and over the angled retention slots  140  disposed in the peripheral top edges  130 ′ of the bottom chassis wall  226 , and over the edge  242  of the flange portion  224 . 
     It should be noted that the above elements are not a limitation and that they may vary according to the specific needs of each enclosure. For example, steel sheet metal may be used to form the bottom plate, and the bottom chassis may be formed from other conductively plated plastic materials. Moreover, the conductive layer may be applied by coating, painting, depositing and/or the like. In addition, the conductive layer may be formed from other suitable materials or coatings such as silver or copper paint. As should be appreciated, the thickness of the conductive layer may vary (larger or smaller) according to the type of material used and the method for applying the material. 
     In a manner analogous to forming the top case  124 , a structural adhesive  250  is also used to structurally attach the bottom chassis  158  to the bottom plate  156  (as shown in  FIG. 8 ). The structural adhesive  250  is configured to exhibit good strength characteristics and good adhesion between the bottom plate  156  and the bottom chassis  158 . The structural adhesive  250  is also configured to reduce tolerance variability in the overall geometry of the bottom case  126 . The adhesive generally has both a compliant state and a binding state. The binding nature of the adhesive  250  is arranged to form a singular composite structure between the two disparate parts (e.g., metal bottom plate and plastic bottom chassis) that is stronger than conventional fastening methods, i.e., bolts, screws, snaps, and inserts. The compliant nature of the adhesive  250  is arranged to absorb geometric variations of two disparate parts (e.g., metal bottom plate and plastic bottom chassis) so as to form a singular composite structure with an overall geometry that is desirable. 
     As shown in  FIG. 8 , the structural adhesive  250  is disposed between the flange portion  224  of the bottom chassis  158  and the bottom surface  220  of the bottom plate  156 . More particularly, the structural adhesive  250  is disposed between an exposed segment  223  of the bottom chassis  158 , and an exposed segment  221  of the bottom plate  156 . By exposed, it is meant that the surface is a non-coated surface. Alternately or additionally, the structural adhesive  250  may be disposed between the bottom chassis wall  226  of the bottom chassis  158  and the bottom plate wall  222  of the bottom plate  156 . 
     In most cases, the bottom surface  220  and the flanged portion  224  are arranged to form a gap G′ therebetween for the placement of the adhesive  250 . The gap G′ is generally disposed between the exposed segment  221  and the exposed segment  223 . In the illustrated embodiment, the size of the gap G′ is defined by a length L 1  of the bottom plate wall  222  and the length L 2  of the bottom chassis wall  226  when the top  130  of the bottom chassis wall  226  and the top  227  of the bottom plate wall  222  are placed at the predetermined offset position O. In most cases, the tolerances of the offset O are tightly controlled to ensure properly interfacing parts. 
     As should be appreciated, the geometric tolerances of the bottom case  124  must be predictable to meet production yield standards. The bottom chassis  158  and bottom plate  156  are typically manufactured using very different processes (e.g., molded plastic and formed sheet metal) representing very different tolerances. Unfortunately, the tolerances of the bottom chassis  158  and the bottom plate  156  may stack thus forming a final assembly (e.g., bottom case  126 ) that doesn&#39;t meet standards. By way of example, tolerance stacking may lead to a bottom case that does not align properly with a top case, i.e., parts that don&#39;t fit together or parts that create undesirable surfaces such as gaps. Referring to  FIG. 8 , if the length L 1  is too large and/or if the length L 2  is too small then a large offset O may be encountered that causes problems when interfacing the top case  124  with the bottom case  126 , i.e., the hooks  138  may not interface with the slots  140 . 
     Accordingly, the adhesive  250  is arranged to absorb geometric variations that may influence a parts position relative to another parts position. That is, the structural adhesive  250  is configured to be compliant so as to conform to the width of the gap G′ even when the tolerances of the parts are at a maximum or minimum. By way of example, variations in the parts may lead to a gap size of between 0.2 and 0.6 mm. In the illustrated embodiment, the width of the compliant adhesive  250  is configured to adjust with the width of the gap G′ to ensure the predetermined offset O. For example, the compliant adhesive  250  is arranged to conform to a larger gap G′ when the length L 1  is at a maximum tolerance and/or when the length L 2  is at a minimum tolerance. In addition, the compliant adhesive  250  is arranged to conform to a smaller gap G′ when the length L 1  is at a minimum tolerance and/or when the length L 2  is at a maximum tolerance. In this way there is no tolerance stacking. That is, slight geometry variations in one part will have no influence on an adjacent parts position in the assembly. 
     In one embodiment, the compliant structural adhesive  250  is a glue that is compliant when dispensed and then cures to a rigid structure over time. In particular, the glue transforms between a liquid state, exhibiting its compliant attributes, and a solid state, exhibiting its structural attributes. In the liquid state, the glue exhibits a readiness to flow and a relatively high incompressibility that allows it to fill the gap (whether small or large). In the solid state, the glue exhibits rigidity and a relatively high resistance to movement that allows it to maintain the width of gap chosen during the liquid state, and to form a singular composite structure. By way of example, the glue may be applied between the bottom plate  156  and the bottom chassis  158  in bead form (liquid state), and after a set time, the glue may harden thus forming a rigid structure that attaches the bottom plate  156  and the bottom chassis  158  (solid state). Generally speaking, the adhesive offers a dynamic way to place multiple parts in desired positions relative to one another and a static way to fix the multiple parts together. In one implementation, the glue is a two-part catalytic epoxy that forms a strong structural bond between the plastic bottom chassis and the metal bottom plate. By way of example, 201/19 epoxy produced by Lord Co. of Erie, Pa., may be used to structurally attach the carbon fiber bottom chassis to the titanium bottom plate. 
     In a manner analogous to forming the top case, a conductive bridge  260  is also used to electrically connect the bottom chassis  158  to the bottom plate  156  when forming the bottom case  126 . In the illustrated embodiment, the conductive bridge  260  is electrically bonded to a portion of the conductive layer  240  and to a portion of the bottom plate  156 . The binding nature of the conductive bridge  260  is arranged to form a singular electrical structure, including the conductive layer  240  and the bottom plate  156 , for shielding the bottom case  126  from electronic emissions. In most cases, the conductive bridge  260  is arranged to seal a gap  262  formed between the bottom surface  220  of the bottom plate  156  and the conductive layer  240  of the bottom chassis  158 , i.e., the conductive bridge  260  is disposed in the gap  262 . As should be appreciated, the gap  262  typically provides an electrical opening where radiation and/or electronic emissions may escape. In general, the conductive bridge  260  provides a better electrical flow therethrough than could be obtained through the bottom plate  156  and conductive surface  240  directly. 
     The conductive bridge  260  of the bottom case  126  is generally formed from a suitable conductive material. In a preferred embodiment, the conductive bridge is formed from a conductive paste that exhibits good electrical characteristics and good adhesion between the conductive layer  240  and the bottom plate  156 . The conductive paste generally has two states—a liquid state and a solid state. In most cases, the conductive paste is applied in its liquid state (between the bottom plate and the bottom chassis) and after a set time it changes to its solid state, i.e., the conductive paste is rigidly set over time, thus forming the electrically integrated structure. For example, the conductive bridge  260  may be formed by dispensing a conductive paste in bead form over a bottom surface  229  of the flange portion  224  of the bottom chassis  158  and allowing the bead to flow over the edge  242  of the flange portion  224  and over the bottom surface  220  of the bottom plate  156  via gravity. 
     In one embodiment, the conductive paste is a metal filled electrically conductive ink that forms a strong electrically bond between the plated top frame and the metal top plate. During several experiments, it was found that a nickel filled electrically conductive ink formed an exceptionally strong electrically bond between the Nickel-Copper plated conductive layer  240  and the titanium bottom plate  156 . It is generally believed that the strong electrical bond is created because of the ability of the nickel to overcome oxidation problems that may be found on the surface of the titanium top plate, i.e., the nickel base conductive ink eats through the oxidation. It was also found that a nickel filled electrically conductive ink having a viscosity of between about 5,000 centipoise to about 10,000 centipoise, and more particularly about 7,500 centipoise works well. Furthermore, Nickel filled electrically conductive ink provides a good balance of low cost and high conductivity. In one embodiment, a nickel filled electrically conductive ink (part no. EE 40-3917) produced by Epoxies, Etc. of Cranston, R.I., may be used. In some implementations, it may desirable to modify the conductive ink (EE 40-3917), which has a viscosity of 14,000 centipoise, to maintain the viscosity mentioned above. For example, an acetate solution may be added to EE 40-3917 to produce a viscosity of between about 5,000 centipoise to about 10,000 centipoise, and more particularly about 7,500 centipoise. 
       FIG. 9  is a flow diagram illustrating a method  300  of constructing an enclosure with a frame and a casing, in accordance with one embodiment of the present invention. By way of example, the frame may be the top frame  154  ( FIGS. 3 ,  5 – 6 ) or the bottom chassis  158  ( FIGS. 4 ,  7 – 8 ), and the casing may be the top plate  152  ( FIGS. 3 ,  5 – 6 ) or the bottom plate  156  ( FIGS. 4 ,  7 – 8 ). The method  400  generally begins at step  402  where the frame and casing are prepared for assembly. In the case where either the frame or casing is formed from a non-conductive material, step  402  includes selectively coating the part with a conductive material. By selectively coating, it is meant that only desired portions of the part are coated, as for example, the interior surfaces of the frame or casing. As should be appreciated, the conductive material is arranged for shielding electronic emissions. By way of example, plating is one suitable implementation for conductively coating the interior surfaces of a non-conductive part. During plating, the non conductive part is dunked into several plating baths containing various solutions until a conductive layer adheres to the selected surfaces. Plating is generally well known in the art and for the sake of brevity will not be described in greater detail. Furthermore, while plating works well for forming a conductive layer, it should be noted that it is not a limitation and that other methods may be used. For example, the conductive layer may be painted on with conductive paint, or deposited on using known deposition techniques. 
     In one embodiment, the frame is formed from a first material, and the casing is formed from a second material that is different than the first material. For example, the frame may be formed from a non-conductive material such as plastic and the casing may be formed from a conductive material such as sheet metal. As such, the frame is typically coated with a conductive layer. With reference to the earlier described embodiments, the top frame  154  and the bottom chassis  158  are generally formed from a plastic material such as carbon fiber plastic, and therefore they are typically lined with a conductive layer, as for example, conductive layers  190  and  240 . 
     Although the invention has been described using a non-conductive frame and a conductive casing, it should be noted that this is not a limitation. For example, in some cases, it may be desirable to make an enclosure with a conductive frame and a non-conductive casing, and in other cases it may be desirable to make an enclosure with a non-conductive frame and a non-conductive casing. In the last example, both the frame and the casing may have a conductive layer applied thereto. In yet other cases, it may be desirable to make an enclosure with a conductive frame and a conductive casing. 
     After preparing the frame and casing, the process flow proceeds to step  404  where the frame is structurally bonded to the casing (or vice versa). This is typically done to form a singular integrated part, i.e., the frame serves to support and provide rigidity to the casing. In one embodiment, the frame is glued to the casing. In the case where the frame and casing are formed from different materials, the glue is arranged to have good adhesion qualities to both the frame and the casing. The binding nature of the glue is arranged to form a singular composite structure between the two disparate parts (e.g., metal bottom plate and plastic bottom chassis) that is stronger than conventional fastening methods, i.e., bolts, screws, snaps, and inserts. For instance, fasteners are typically located at discrete points at the interface of two parts, and glue is applied over a large surface area at the interface of two parts. In some cases, the glue is applied in bead form on a predetermined surface of the frame, in other cases the glue is applied in bead form on a predetermined surface of the casing. In either case, the frame and casing are brought together at the glue interface to bind the two disparate parts together. After a set time, the glue adheres to the adjacent surfaces of the two parts and hardens thus forming an integrated structure. In addition to providing a stronger structure, the glue also provides dimensional stability that is not found using conventional methods. That is, the glue in its liquid state can fill gaps found at the interface of the two parts and thus closely held tolerances can be maintained. 
     After structurally bonding the frame to the casing, the process flow proceeds to step  406  where the frame is electrically bonded to the casing (or vice versa). This is typically done to form a singular integrated part that can shield electronic devices that are contained therein. As should be appreciated, in the process of gluing the frame to the casing, a gap is typically formed therebetween that may provide an opening for the transmission of the electronic emissions. In one embodiment, the gap is filled using a conductive paste. In the case where the conductive portions of the frame and casing are formed from different materials, the paste is arranged to have good adhesion qualities to both the conductive portions of the frame and the conductive portions of the casing. The binding nature of the paste is arranged to form a singular electrical shield between the two disparate parts (e.g., metal top plate and plated top frame). 
     Referring to FIGS.  10  and  11 A–C a method  304  for structurally bonding the frame to the casing will be disclosed.  FIG. 10  is a flow diagram, and  FIGS. 11A–C  are side elevation views of the frame and casing, illustrating the steps of the method, in accordance with one embodiment of the present invention. For ease of discussion,  FIG. 11  corresponds to the embodiments shown in  FIGS. 3 , and  5 – 6 . Thus,  FIG. 11  is a side elevation view, in cross section, of the top case  124  including the top plate  152  (e.g., casing) and the top frame  154  (e.g., frame). However, it should be noted, that the following method can also be applied to the embodiments shown in  FIGS. 4 , and  7 – 8  (e.g., bottom case  126 ) as well. The method  404  generally begins at step  500  where a glue is dispensed onto the frame or casing. The glue is generally arranged for structurally bonding the frame to the casing. That is, the glue has properties that allows it to adhere to the frame and the casing so as to form a singular integrated structure, as for example, the top case  124  or the bottom case  126 . 
     As shown in  FIG. 11A , a liquid glue  200 ″ is dispensed on the top frame  154 , and more particularly the flanged portion  164  of the top frame  154 . The liquid glue  200 ″ is generally dispensed through a nozzle  270  onto the exposed surface  202  (i.e., not the conductive surface  190 ) of the top frame  154 . By way of example, the liquid glue  200 ″ may be dispensed through the nozzle  270  via a handheld applicator or via a robotically controlled applicator tool. Nozzles are conventional and well known in the art and for the sake of brevity will not be discussed in greater detail. In most cases, the glue is applied along a predetermined path (either robotically or by hand) that generally corresponds to the areas of desired contact between the frame and the casing. In context of the top case  124  (as shown in  FIG. 6 ), the liquid glue  200 ″ is applied to the interface between the recessed portion  166  of the top plate  152  and the flanged portion  164  of the top frame  154 . In context of the bottom case  126  (as shown in  FIG. 8 ), the glue is applied to the interface between the bottom surface  220  of the bottom plate  156  and the flanged portion  224  of the bottom chassis  158  (including the flanged rib  236 ). 
     After dispensing the glue, the process flow proceeds to step  502  where a force is applied to sandwich the glue between the frame and the casing. For instance, after dispensing the glue, the casing is placed over the frame and pushed into contact with the glue, which is disposed on the surface of the frame. As shown in  FIG. 11B , a force F is applied to the top plate  152  thereby squeezing the liquid glue  200 ″ between the recessed portion  166  and the flanged portion  164 . In most cases, this process is continued until the top surface  168  of the top plate  152  is flush with the top surface  170  of the top frame  152 , i.e., the surfaces  168 ,  170  are planar. The amount of glue  200 ″ applied to the interface generally depends on the size of the recessed portion  166  and the gap formed between a surface  204  of the recessed portion  166  and a surface  202  of the flanged portion  164  when the surfaces  168  and  170  are made flush. As should be appreciated, it is generally desirable to fill this area so as to form a sufficient bond. 
     After applying the force, the process flow proceeds to step  504  where the glue is allowed to set, thus placing the frame and casing in a predetermined position relative to one another. As shown in  FIG. 11C , the liquid glue  200 ″ changes into a solid binder  200 , thus forming an integrated structure, i.e., top case  124 . Furthermore, as mentioned previously, the predetermined position is generally a position that places the surfaces  168  and  170  planar, i.e., flush, with one another. The set time is generally dependent on the type of glue used to bind the two disparate parts together. 
       FIG. 12  is a flow diagram illustrating a method for structurally coupling a frame to a casing, in accordance with another embodiment of the present invention. As should be appreciated, the casings (e.g., top plate  152  and bottom plate  156 ) and the frames (e.g., top frame  154  and bottom chassis  158 ) must be glued together via an accurate and repeatable process. Generally speaking, the assemblies can only be glued once and typically none of the parts are recoverable. As such,  FIG. 12  describes a process that uses a highly precise first fixture to position a frame or casing during gluing, a robotically controlled nozzle to precisely place the glue along a predetermined path of a frame or casing, and a highly precise second fixture working with the first fixture to precisely position the frame relative to the casing during curing. In most cases, the fixtures are configured to adjust for tolerances in the frame and casing, and thus the fixtures define the tolerances of the final assembly. 
     The method  404  generally begins at step  600  where the frame is placed in a highly geometrically accurate first fixture. By way of example, the first fixture may be machined to make its dimensions highly accurate. The first fixture is preferably designed to securely hold the frame therein, and to hold the frame in a fixed position relative to a reference element of the fixture. By way of example, the reference element may be a surface or protrusion that is configured to contact a specific location(s) on the frame to hold the frame in the X, Y and/or Z directions. In one embodiment, a part or parts of the frame are arranged to locate flush against a datum surface(s) in the first fixture. As such, the critical controlling geometries of the assembly (E.g., top case or bottom case) are determined directly by the precision machining of the first fixture. In one implementation, the first fixture includes a planar reference surface configured for abutting a planar surface of the frame. By way of example, and referring to  FIG. 11A , the top surface  170  of the top frame  154  may be precisely positioned on a planar reference surface  271  of a fixture  272  so as to place the exposed surface  202  in a known position. 
     After the frame is placed in the first fixture, the process flow proceeds to step  602  where the first fixture is placed into an application tool. Broadly, the application tool is arranged for automatically dispensing a glue along a predetermined path relative to the frame. More specifically, the application tool includes a stage, a nozzle, and a robot. Although not shown, the stage is configured to support and receive the first fixture so as to precisely hold the fixture in the X, Y and Z directions. In most cases, the stage is positioned below the nozzle in the Z-direction. The nozzle is configured to dispense the glue onto the surface of the frame when the fixture is securely held by the stage. In most cases, the nozzle dispenses the glue in the Z-direction (as shown in  FIG. 11A ). Furthermore, the robot is configured to move the nozzle within a single plane relative to the frame, i.e., the robot moves the nozzle in both the X and Y directions. The application tool also includes a controller for controlling the movements of the robot, and thus the location of the nozzle. 
     After the first fixture is placed in the application tool, the process flow proceeds to step  604  where a glue is robotically dispensed onto the frame. The glue is generally arranged for structurally bonding the frame to the casing. That is, the glue has properties that allows it to adhere to the frame and the casing so as to form a singular integrated structure, as for example, the top case  124  or the bottom case  126 . In one embodiment, the application tool is preprogrammed so that the nozzle is automatically moved (via the robot) relative to the frame. By way of example, the robot may be preprogrammed to move in the X &amp; Y directions so as to follow the perimeter of the top frame  154 , and more particularly the flanged portion  164  of the top frame  154 . After the glue is dispensed, the process flow proceeds to step  506  where the first fixture is removed from the application tool. 
     During steps  600  to  606 , the process flow continues in a separate sequence (in parallel to steps  600 – 606 ) to step  608  where the casing is placed in a highly geometrically accurate second fixture. By way of example, the second fixture may be machined to make its dimensions highly accurate. The second fixture is preferably designed to securely hold the casing therein, and to hold the casing in a fixed position relative to a reference element of the fixture. By way of example, the reference element may be a surface or protrusion that is configured to contact a specific location(s) on the frame to hold the frame in the X, Y and/or Z directions. In one embodiment, a part or parts of the frame are arranged to locate flush against a datum surface(s) in the second fixture. As such, the critical controlling geometries of the assembly are determined at least by the precision machining of the second fixture. In one implementation, the first fixture includes a planar reference surface configured for abutting a planar surface of the casing. By way of example, and referring to  FIG. 11B , a bottom surface  169  of the top plate  154  may be positioned on a reference surface  275  of a second fixture  274  so as to place the exposed surface  204  in a known position. 
     After steps  606  and  608  are completed, the process flow proceeds to step  610  where the first and second fixtures are clamped together. The two fixtures are configured to mate with each other so as to locate all the various parts of the frame and housing. In one embodiment, the first and second fixtures are configured for engagement so as to precisely place the frame relative to the casing in the X and Y directions, and to sandwich the glue between the frame and the casing in the Z direction. By way of example, the first fixture may be a lower fixture that includes guides, and the second fixture may by an upper fixture that includes guide holes that cooperate with the guides, and wherein the guides and guide holes position the fixtures relative to one another in the X &amp; Y directions, and allow movement of the fixtures in the Z-direction. 
     As shown in  FIG. 11B , when the force F is applied to the fixtures  272 ,  274 , the fixtures  272 ,  274  are made to move towards one another thus forcing the top plate  152  to move towards the top frame  154 . As the top plate  152  moves towards the top frame  154 , the recessed portion  166  comes into contact with the liquid glue  200 ″, and under further force squeezes the liquid glue  200 ″ between the surface  204  of the recessed portion  166  and the surface  202  of the flanged portion  164 . This process is continued until the top surface  168  of the top plate  152  abuts the reference surface  271  of the first fixture  272  thereby ensuring that the top surface  168  of the top plate  152  is made flush with the top surface  170  of the top frame  152 . The amount of glue  200 ″ applied to the interface generally depends on the size of the recessed portion  166  and the gap formed between the surface  204  of the recessed portion  166  and the surface  202  of the flanged portion  164  when the surfaces  168  and  170  are made flush. As should be appreciated, it is generally desirable to fill this area so as to form a sufficient bond. 
     After the fixtures are clamped, the process flow proceeds to step  612  where the glue is allowed set, thus placing the frame and casing in a predetermined position relative to one another. As shown in  FIG. 11C , the liquid glue  200 ″ changes into a solid binder  200 , thus forming an integrated structure, i.e., top case  124 . Furthermore, as mentioned previously, the predetermined position is generally a position that places the surfaces  168  and  170  planar, i.e., flush, with one another. The set time is generally dependent on the type of glue used to bind the two parts together. After the glue has set, the process flow proceeds to step  514  where integrated frame/casing structure is removed from the first and second fixtures. 
     As should be appreciated, any geometric variations in the frame and/or casing is completely absorbed in the thickness of the glue bond of the final assembly. The tolerance between datum surfaces on any part (excluding the final assembly) is the same as the standard machining tolerance on the first fixture or second fixture (e.g., +/−0.0005 mm). The tolerance between any of the combined parts is the root mean squared tolerance of the first and second fixtures together (+/−0.007 mm). Thus, the final glued assembly, though it represents parts made by different processes in many places by many vendors, ultimately has the geometric stability of a single machined part. 
     It is the tight tolerance and the repeatability that make this so advantageous. It uses the properties of the glue bond to eliminate tolerance deviations from adjacent or unique parts, thereby making the assembly much more precise than one in which tolerances stack. The repeatability comes from the use of the fixture(s) to drive the critical dimensions-every part coming off that fixture will have the tolerances of the fixture and thus they are repeatable. Glue also allows attachment locations to match very closely with other parts. That is, driving the tolerances so tight allows for a portable computer that is absolutely minimal. With tolerance of machined parts, the display assembly can be reduced to the minimum necessary. 
     Referring to FIGS.  13  and  14 A–D a method  406  for electrically bonding the frame to the casing will be disclosed.  FIG. 13  is a flow diagram, and  FIGS. 14A–D  are side elevation views of the frame and casing, illustrating the steps of the method, in accordance with one embodiment of the present invention. For ease of discussion,  FIG. 14  corresponds to the embodiments shown in FIGS.  3  and  5 – 6 . Thus,  FIG. 14  is a side elevation view, in cross section, of the top case  124  including the top plate  152  (e.g., casing) and the top frame  154  (e.g., frame). However, it should be noted, that the following method can also be applied to the embodiments shown in  FIGS. 4 ,  7 – 8  (e.g., bottom case  126 ). The method  406  generally begins at step  700  where a conductive paste is dispensed onto a conductive surface of the frame or casing. The paste is generally arranged for electrically bonding the frame to the casing. That is, the paste has properties that allows it to adhere to the frame and the casing so as to form a singular electrical element. 
     As shown in  FIGS. 14A  &amp; B, a liquid paste  210 ″ is dispensed on the top plate  152 , and more particularly the recessed portion  166  of the top plate  152 . The liquid paste  210 ″ is generally dispensed through a nozzle  276  onto the edge  278  of the top plate  152 . By way of example, the liquid paste  210 ″ may be dispensed through the nozzle  276  via a handheld applicator or via a robotically controlled applicator tool. Nozzles are conventional and well known in the art and for the sake of brevity will not be discussed in greater detail. In most cases, the paste is applied along a predetermined path (either robotically or by hand) that generally corresponds to the areas of desired contact between the frame and the casing. In context of the top case  124  (as shown in  FIGS. 5&amp;6 ), the liquid paste  210 ″ is applied so as to the fill the gap  212  between the recessed portion  166  of the top plate  152  and the conductive layer  190  of the top frame  154 . In context of the bottom case  126  (as shown in  FIGS. 7&amp;8 ), the paste is applied so as to fill the gap  262  between the bottom surface  220  of the bottom plate  156  and the conductive layer  240  of the bottom chassis  158  (including the flanged rib  236 ). 
     In one embodiment, the nozzle is moved relative to the final assembly so as to seal the perimeter of the interface between the frame and the casing. As shown in  FIG. 5 , the entire interface between the conductive portion  190  and the recessed portion  166  is filled with the conductive paste  210 . As shown in  FIG. 7 , the entire interface between the conductive portion  240  and the bottom surface  220  is filled with the conductive paste  260 . It should be noted, however, that this is not a limitation and that the method described herein can also be applied to specific regions of an enclosure having increased emissions. By way of example, the conductive paste may be applied to I/O areas, card slots and the like. Moreover, it should also be noted that the nozzle does not have to follow a straight pattern. For example, it may be desirable to move around a certain area or object, i.e., may cause cosmetic problems by seaping through an opening. In one implementation, and referring to  FIG. 4 , the conductive paste  210  is dispensed around a first boss  280  and a second boss  282 . In another implementation, and referring to  FIG. 7 , the conductive paste  260  is dispensed around the opening  232  and protrusions  288  and  299 . 
     In some cases it may be difficult to reach the gap  212  because of obstructions along the predetermined path. By way of example, the frame or casing may include a protrusion that extends into the desired pathway thus obstructing the movement of the nozzle. This is generally more of a concern when using a robotically controlled nozzle. As shown in  FIG. 14B , the wall  172  of the top frame  154  includes a protrusion  296  that extends past the inner periphery  174  of the wall  172 . In one embodiment, the top case  124  may be configured to tilt at an angle θ to overcome the obstruction. That is, the top case  124  may be tilted to allow the upright needle to continue its movements without impediments. Additionally or alternatively, the needle itself may be configured to apply paste at an angle. 
     After the paste is dispensed, the process flow proceeds to step  702  where the conductive paste is caused to flow from the conductive surface of the frame to the conductive surface of the casing or vice versa. In one embodiment, the needle is centered on the edge of the frame so that the conductive paste first engages a conductive portion of the frame and then flows down the side of the frame via gravity to a conductive portion of the casing (e.g., bottom case  126 ). In another embodiment, the needle is centered on the edge of the casing so that the conductive paste first engages a conductive portion of the casing and then flows down the side of the casing via gravity to a conductive portion of the frame (e.g., top case  124 ). As should be appreciated, gravity is the only force needed to apply the conductive paste, i.e., the paste is put on as a liquid and allowed to flow. Because of this, the process of applying the conductive paste does not need additional compressive forces from such items as screws, fasteners, and the like. 
     As shown in  FIG. 14C , the dispensed liquid paste  210 ″ begins to flow from the point of application (e.g., the comer  278  of the recessed portion  166 ) to a point beneath the point of application (e.g., the gap  212 ) via the force of gravity. In general, as the paste  210 ″ moves, the paste  210 ″ adheres to the bottom surface  169  of the recessed portion  166 , the side edge  298  of the recessed portion  166  disposed below the top surface, and the conductive layer  190  disposed below the side edge  298 . It should be noted, however, that this is not a limitation and that the paste may be applied at other locations so much as the liquid paste adheres to a conductive surface of the top plate and a conductive surface of the top frame while filling the gap therebetween. 
     After the paste is caused to flow, the process flow proceeds to step  704  where the conductive paste is allowed to set so as to electrically seal a gap found between the conductive surfaces of the frame and casing. As shown in  FIG. 14D , the liquid paste  210 ″ filled the gap  212  between the recessed portion  166  and the conductive layer  190 , and solidified to form the conductive bridge  210  that electrically connects the conductive top plate  152  to the conductive layer  190  of the non-conductive top frame  154 . 
     In a preferred embodiment of the invention, the conductive paste is dispensed in a robotically controlled application tool. The application tool is generally arranged for automatically dispensing a paste along a predetermined path relative to the final assembly. Robotically dispensed paste allows material to be strategically placed, reduces waste and reduces sample to sample variations. As such, the casings and the frames can be electrically connected via an accurate and repeatable process. 
     To facilitate discussion,  FIG. 15  shows a robotically controlled application tool  300 , in accordance with one embodiment of the invention. The application tool  300  generally includes a fixture  302 , a nozzle  306 , and a robot  308 . The fixture  302  is configured to securely hold an assembly  310  therein, and to hold the assembly  310  in a fixed position relative to a reference element of the fixture  302 . In most cases, the fixture  302  is configured to precisely hold the assembly  310  in the X, Y and Z directions. Furthermore, the fixture  302  is generally positioned below the nozzle  306  in the Z-direction. The nozzle  306  is configured to dispense a conductive paste  312  onto the surface of the final assembly  310 . In most cases, the nozzle  306  dispenses the paste  312  in the Z-direction. Furthermore, the robot  308  is configured to move the nozzle  306  within a single plane relative to the fixture  302 , and more particularly the assembly  310 , i.e., the robot moves the nozzle in both the X and Y directions. The application tool  300  also includes a controller  314  for controlling the movements of the robot  308 , and thus the location of the nozzle  306 . 
     As should be appreciated, the nozzle  306  may be the nozzle  276  (as shown in  FIG. 14 ), the assembly  310  may be the top case  124  or the bottom case  126 , and the conductive paste  312  may be the conductive paste  210  or  260  as shown in  FIGS. 3–8 . 
     In one embodiment, the application tool  300  also includes a dispensing mechanism  316  for supplying the paste  312  to the nozzle  306 , and for keeping the paste  312  mixed up so as to reduce separation between the conductive agent and the carrying agent. The dispensing mechanism  316  generally includes a holding tank  318 , an agitator  320 , a pump  322 , a supply line  324 , a valve  326 , a feed line  328 , and a return line  330 . The tank  318  is configured to hold the conductive paste  312 . The pump  322  is configured to continuously pump the paste to and from the tank  318 . The agitator  320  is configured to keep the conductive particles suspended and evenly mixed. By way of example, the agitator  320  may be a stirring device. The supply line  324  is configured to deliver the paste  312  to the valve  326 . As such, the supply line  324  has in inlet coupled to the tank  318  and an outlet coupled to the valve  326 . 
     The valve  326  is configured to regulate the flow of the paste  312  to the feed line  328  and the return line  330 . In general, the valve  326  has a first condition, flowing the paste  312  to the nozzle  306  through the feed line  328 , and a second condition, flowing the paste  312  back to the holding tank  318  through the return line  330 . In most cases, the valve  326  is biased in the second condition so as to keep the paste  312  continuously flowing when the paste  312  is not being dispensed through the nozzle  306 . By way of example, the valve  326  may be a diverter valve. The feed line  328  is configured to deliver the paste  312  to the nozzle  306  so that the paste  312  can be dispensed on the assembly  310 . As such, the feed line  328  has an inlet coupled to the valve  326  and an outlet coupled to the nozzle  306 . The return line  330 , on the other hand, is configured to deliver the paste  312  back to the holding tank  318 . As such, the return line  330  has an inlet coupled to the valve  326  and an outlet coupled to the holding tank  318 . In one embodiment, the controller  314  is also configured to control the dispensing mechanism  316 , as for example, the valve  326 , agitator  320 , and pump  322 . 
     While this invention has been described in terms of several preferred embodiments, there are alterations, permutations, and equivalents, which fall within the scope of this invention. For example, although the present invention has been described as using a structural glue and conductive paste to assemble metal to plastic, it should be noted that it can also be used to assemble plastic to plastic or metal to metal. Furthermore, although the present invention has been described as using molded plastic and formed sheet metal, it should be noted that it can also be used in a wide range of manufactured parts including, die cast metal, extruded metal, thixo-molded metal, ceramics and the like. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present invention. For example, the methods of the present invention can also be applied to other parts of the enclosure such as structural components located inside the frame and casing. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.

Metadata:
Filing Date: 20040827
Publication Date: 20071225
Grant Date: 20071225
Priority Date: 20010328
Inventors: KRIEGE MICHAEL
HONG DAN
DIFONZO JOHN
ZADESKY STEPHEN
LYNCH DAVID
LUNDGREN DAVID
MERZ NICK
Assignee: APPLE INC
CPC Classifications: [{"code": "Y10T29/49151", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49147", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49155", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49126", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/4913", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49151", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": true, "tree": "[]"}, {"code": "Y10T29/4913", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1679", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/182", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y10T29/49171", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": true, "tree": "[]"}, {"code": "Y10T29/49126", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49171", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49155", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/182", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y10T29/49117", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1679", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y10T29/49117", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49147", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1656", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1656", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 25234298