PATENT DOCUMENT

Publication Number: US-8196636-B2
Application Number: US-84290510-A
Country: US
Kind Code: B2

Title: 3-dimensional curved substrate lamination

Abstract:
A method of laminating a surface of a flexible material to a surface of a rigid, curved material. The method includes pressing an area of the surface of the flexible material into the surface of the rigid, curved material with a holder to create a contact area while the flexible material is conformed to the holder, which has a curvature greater than a curvature of the rigid, curved material surface; and changing the contact area between the surface of the flexible material and the surface of the rigid, curved material while maintaining pressure on the contact area until the surface of the flexible material and the surface of the rigid curved material are laminated.

Claims:
1. An apparatus for laminating a surface of a flexible material to a surface of a curved material, the apparatus comprising:
 a first holder configured for contacting the flexible material; 
 a second holder configured for contacting the curved material; 
 a support holder having a plurality of alignment pins for supporting the flexible material as a flat surface spaced apart from a contact surface of the first holder and the curved material; 
 a pressure applying device configured for pressing the first holder against the flexible material to cause the flexible material to press against the curved material at a first portion of the flexible material at a pressure region between the surface of the flexible material and the surface of the curved material; 
 articulation means for shifting the first holder across the flexible member, the articulation means causing translation of the first holder along both an x and y direction while moving the first holder toward the second holder along a z direction, thus changing at least the position of the pressure region to laminate the flexible material to the curved material and remove air bubbles between the laminated flexible material and the curved material. 
 
     
     
       2. The apparatus of  claim 1 , wherein the flexible material is a substantially planar circuit board. 
     
     
       3. The apparatus of  claim 1 , wherein the flexible material comprises a plurality of conductive traces on its surface and an insulating layer deposited over the conductive traces. 
     
     
       4. The apparatus of  claim 1 , wherein the laminated flexible material and the curved material are a part of a sensor array, and the sensor array is a part of a multi-touch mouse. 
     
     
       5. The apparatus of  claim 1 , further comprising an adhesive adapted to laminate the flexible material and the curved material, the adhesive selected from a group consisting of pressure-sensitive adhesives (PSAs), re-workable PSAs, thermoplastic film, thermoset film, thermal cure liquid, UV curing liquid, and multiple-component adhesives. 
     
     
       6. The apparatus of  claim 1 , wherein the support holder is part of the second holder. 
     
     
       7. The apparatus of  claim 1 , wherein the first holder is made of a deformable material. 
     
     
       8. The apparatus of  claim 1 , wherein the pressure applying device is adapted to change an amount of pressure applied to the surface of the flexible material and the surface of the curved material. 
     
     
       9. The apparatus of  claim 1 , wherein the change of the pressure region is in response to a shape of at least one of the first holder and the second holder. 
     
     
       10. The apparatus of  claim 1 , wherein the articulation means comprising a gimbal adapted to control movement of the first holder and create a rolling motion of the first holder. 
     
     
       11. The apparatus of  claim 1 , further comprising a microbead surface adapted to be walked over the flexible material to remove air bubbles between the laminated flexible material and the curved material. 
     
     
       12. The apparatus of  claim 11 , wherein the flexible material has a conductive trace pattern and microbeads on the microbead surface have a size and spacing to conform to the conductive trace pattern. 
     
     
       13. The apparatus of  claim 12 , wherein the conductive trace pattern has a plurality of peaks and valleys and the microbeads protrude into the valleys to push air to a perimeter of the laminated flexible material and the curved material during walking. 
     
     
       14. The apparatus of  claim 1 , wherein break away tabs secure the flexible material to the alignment pins, the break away tabs configured to detach the flexible material from the alignment pins under pressure. 
     
     
       15. The apparatus of  claim 14 , further comprising a microbead surface adapted to be walked over the flexible material to remove air bubbles between the laminated flexible material and the curved material. 
     
     
       16. The apparatus of  claim 15 , wherein the flexible material has a conductive trace pattern and microbeads on the microbead surface have a size and spacing to conform to the conductive trace pattern. 
     
     
       17. The apparatus of  claim 16 , wherein the conductive trace pattern has a plurality of peaks and valleys and the microbeads protrude into the valleys to push air to a perimeter of the laminate during walking.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 12/237,281, filed on Sep. 24, 2008, which claims priority to U.S. Provisional Patent Application Nos. 61/126,864 filed on May 7, 2008 and 61/078,325 filed on Jul. 3, 2008, the entire disclosures of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to lamination of flexible or rigid materials, and more particularly, to lamination of materials to a curved, rigid substrate. 
     BACKGROUND OF THE INVENTION 
     Conventional lamination processes are adequate for laminating a substantially flat/planar material to a substantially flat/planar substrate. For example, in the field of electronic devices, many conventional methods exist to laminate a planar printed circuit board to a planar substrate, such as another planar printed circuit board, to form a single, laminated circuit board. However, conventional techniques may not work when the substrate is substantially curved. 
     SUMMARY OF THE INVENTION 
     Laminating a flexible material to a curved substrate can pose several difficulties, particularly when the process is applied in the field of electronic devices. For example, it may be more difficult to prevent air bubbles from getting trapped between a flexible material and a curved substrate during lamination than between rigid straight material. In some electronics applications, for example, laminates must meet strict quality requirements that limit the number and/or size of trapped air bubbles. If a laminate has too many trapped air bubbles, or if the air bubbles are too large, the laminate must often be discarded as defective, resulting in lost time and money. Even if the adhesive used in the defective laminate can be reworked to reduce trapped bubbles, the re-lamination process would still result in lost time. In addition, the materials used in the laminates of some electronic devices can be relatively delicate. This limits the maximum pressure that can be applied during lamination. 
     In one embodiment of the invention, a lamination system includes a base and an upper portion. The base includes a lower holder. The upper portion includes an upper holder and control circuitry. The lower holder includes a lower contact surface that is placed in contact with a non-lamination surface of a substrate, such as the non-lamination surface of the substrate. The upper holder includes an upper contact surface that is placed in contact with a non-lamination surface of a flexible material, such as the non-lamination surface of the flexible material. The lower holder and the upper holder may each be mounted to a motion block. The lower and upper motion blocks can provide various types of motion to the holders ranging from single axis motion to fully articulated motion, depending on the requirement of the particular lamination system. Different embodiments of the disclosed lamination system are described in more detail below. 
     During the lamination process, the lamination surfaces are brought together with an adhesive material in between. Various types of adhesives can be used, including pressure-sensitive adhesives (PSAs), re-workable PSAs, thermoplastic film, thermoset film, thermal cure liquid (single or multiple components), ultraviolet (UV) cure liquid, and multiple-component adhesives that cure at room temperature. The adhesive(s) may be applied to the substrate, the flexible material, or both. In addition, the adhesive(s) may be applied as a sheet or sheets, and/or one or more regions of liquid adhesive. As the lamination surfaces are brought into contact, a force-applying area of the upper contact surface and a force-applying area of the lower contact surface apply opposing forces to press together the substrate and the flexible material in a pressure region between the upper and lower force-applying areas. The portions of the substrate and the flexible material in the pressure region are pressed together and laminated with the adhesive material. Either or both of the lower holder and the upper holder may be heated to improve adhesive properties. Lamination may also be performed at or below room temperature. 
     In another embodiment, a lower holder is a base chuck formed of a rigid material, such as glass or a metal. The lower holder has a lower contact surface that is shaped to conform to a non-lamination surface of a curved substrate. An upper holder is a vacuum chuck formed of a compliant material, such as rubber. The upper holder has an upper contact surface with vacuum holes (not shown) to hold a non-lamination surface of a flexible printed circuit board (PCB) in place on the upper contact surface. Thus, flexible PCB is forced into the shape of upper contact surface. In one embodiment, the upper contact surface initially has a higher curvature than the lower contact surface. 
     During an early stage of a lamination process, the upper holder is moved along a z-axis direction towards the lower holder, causing a lamination surface of flexible PCB to contact a lamination surface of curved substrate initially at a single-point, causing the lamination surfaces to be pressed together in a pressure region between force-applying areas of the upper contact surface and the lower contact surface, respectively. As the lamination process continues, the upper holder is pressed further in the z-direction, against the lower holder. The increasing pressure causes the size of the pressure region to grow larger. 
     During a latter part of the lamination process, after upper holder has been moved further along the z-axis towards lower holder. Because upper holder is made of a compliant material, the motion has caused the upper holder to deform. Now, the contact area between the lamination surface of the PCB and the lamination surface of the curved substrate becomes greater than it was during the early stage of the lamination process. The larger contact area causes the lamination surfaces to be pressed against each other in a larger pressure region between larger force-applying areas of the upper contact surface and the lower contact surface, respectively. In this embodiment, the process continues until the pressure region expands to cover the entire lamination surfaces. 
     Because the pressure region begins as a single point and expands from that point during the lamination process, surrounding air may be less likely to become trapped between the flexible PCB and curved substrate as a result of air being pushed out and away from the center as the process continues. Therefore, the lamination system according to this embodiment may potentially reduce or eliminate the formation of air bubbles caused during lamination. In addition, because the upper holder is formed of a compliant material, the present example embodiment may be better-suited for lamination of relatively delicate materials. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates examples of a curved substrate and a flexible material according to embodiments of the invention. 
         FIG. 1B  illustrates the curved substrate and the flexible material of  FIG. 1A  laminated together according to embodiments of the invention. 
         FIGS. 2A and 2B  are cross-sectional views showing details of the curvature of the substrate in the y-direction and the x-direction, respectively, according to embodiments of the invention. 
         FIG. 3  is a more detailed, cross-sectional view of a portion of the flexible material according to embodiments of the invention. 
         FIG. 4A  illustrates an exemplary curved surface for a sensor array according to embodiments of this invention. 
         FIG. 4B  illustrates an exemplary “butterfly” pattern for a sensor array according to embodiments of this invention. 
         FIG. 4C  illustrates an exemplary two-strip sensor array pattern according to embodiments of this invention. 
         FIG. 4D  illustrates an exemplary three-strip sensor array pattern according to embodiments of this invention. 
         FIG. 4E  illustrates an exemplary flat sensor pattern in a “snail” pattern that can be applied to a curved surface according to embodiments of this invention. 
         FIG. 5  illustrates an exemplary lamination system according to embodiments of the invention. 
         FIGS. 6-8  are cross-sectional views illustrating the operation of a lower holder and an upper holder of an exemplary lamination system according to embodiments of the invention. 
         FIGS. 9A and 9B  are cross-sectional views illustrating the operation of a lower holder and an upper holder of another exemplary lamination system according to embodiments of the invention. 
         FIGS. 10A-C  are cross-sectional views illustrating the operation of a lower holder and an upper holder of another exemplary lamination system according to embodiments of the invention. 
         FIGS. 11A and 11B  illustrate the operation of a lower holder and an upper holder of another exemplary lamination system according to embodiments of the invention. 
         FIGS. 12A-E  each shows three top views taken along the z-axis of the substrate at progressively increasing times during the second stage to illustrate various ways in which pressure region can change depending on the different configurations of the lamination system according to embodiments of the invention. 
         FIGS. 13A and 13B  illustrate a substrate and flexible material with multi-axis curvatures according to embodiments of the invention. 
         FIGS. 14A-D  illustrate the operation of a lower holder and an upper holder of another exemplary lamination system according to embodiments of the invention. 
         FIG. 15  illustrates the operation of an upper holder of another exemplary lamination system according to embodiments of the invention. 
         FIGS. 16-18  illustrate the operation of a lower holder and an upper holder of another exemplary lamination system according to embodiments of the invention. 
         FIGS. 19-21  illustrate the operation of a lower holder and an upper holder of yet another exemplary lamination system according to embodiments of the invention. 
         FIG. 22  illustrates the operation of a lower holder and an upper holder of yet another exemplary lamination system according to embodiments of the invention. 
         FIGS. 23A-B ,  24 A-C, and  25  illustrate various exemplary alignment structures that can be used to help align a flexible material according to embodiments of the invention. 
         FIG. 26  is a perspective view illustrating a 2-step process for laminating a printed circuit board (PCB) to a curved substrate according to embodiments of the invention. 
         FIG. 27  is a perspective view illustrating a 1-step process for laminating a PCB to a curved substrate. 
         FIGS. 28A-C  illustrates the operation of a lower holder and an upper holder of another example lamination system according to embodiments of the invention. 
         FIGS. 29A-B  illustrate a post-lamination device and process according to embodiments of the invention. 
         FIG. 30  illustrates a perforated substrate according to embodiments of this invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the following description of preferred embodiments, reference is made to the accompanying drawings, in which it is shown by way of illustration specific embodiments in which the invention can be practiced. It is to be understood that other embodiments can be used and structural changes can be made without departing from the scope of the embodiments of this invention. 
     For the sake of clarity, many of the figures do not show an adhesive used in the lamination processes described below. However, it is understood that an adhesive or other approach that allows the fixing together of two materials may be used in these processes. 
     The present disclosure relates to apparatus and methods for laminating a rigid or flexible material to a curved substrate. 
       FIGS. 1A and 1B  are perspective drawings illustrating examples of a curved substrate  101  and a flexible material  103  that may be laminated together according to embodiments of the invention. In particular,  FIG. 1A  shows the substrate  101  and the flexible material  103  before lamination. As illustrated, the substrate  101  and the flexible material  103  have lamination surfaces  105  and  107 , respectively, adapted to be laminated together. The substrate  101  and the flexible material  103  also have non-lamination surfaces  109  and  111 , respectively, that are opposite the lamination surfaces. In this embodiment, the substrate  101  may be a glass plate that is curved along more than one axis, i.e., multi-axis curvature. Other substrates suitable for lamination may include plastics, ceramics, and other materials. As illustrated in  FIG. 1A , substrate  101  is curved in both the x-axis and the y-axis. A closer view of the curvature of substrate  101  is provided in  FIGS. 2A and 2B . 
       FIG. 1B  shows the substrate  101  and the flexible material  103  having their respective lamination surfaces (not shown) fixed together as a result of the lamination process. 
       FIGS. 2A and 2B  are cross-sectional views showing details of the curvature of the substrate  101  in the y-direction and the x-direction, respectively. The degree of curvature in each axis may or may not be the same. In this embodiment, the figures show that the curvature of the substrate  101  along the y-axis is generally greater than the curvature along the x-axis. In addition, the curvature of the substrate  101  can vary along an axis. For example,  FIG. 2A  shows a portion  201  nearer to an edge of the substrate  101  along the y-axis and a portion  203  nearer to the center of the substrate  101  along the y-axis. Portions  201  and  203  are magnified to illustrate that the curvature of portion  201  is greater than the curvature of portion  203 . In other words, the substrate  101  is straighter near its center than at its edges. 
     Referring again to  FIG. 1A , in this embodiment, flexible material  103  is a substantially planar circuit board. In particular, the circuit board is formed by, for example, depositing circuit elements, such as resistors, capacitors, transistors, and/or conductive traces (e.g., wires) onto a flexible board substrate. An insulating layer can be deposited over the circuit elements to protect against environmental elements such as moisture, as well as to provide a smoother surface for lamination. However, the surface of the insulating material may not be perfectly smooth. In other embodiments, the flexible material  103  may be an optically transparent material, such as a plastic with patterned indium tin oxide (ITO). 
       FIG. 3  is a more detailed, cross-sectional view of a portion of the flexible material  103 .  FIG. 3  shows conductive traces  301  on a flexible board substrate  303 , and an insulating layer  305  deposited over the conductive traces  301 . Because the conductive traces  301  protrude from the surface of the board substrate  303 , the surface of the insulating layer  305  has “peaks”  307  over the conductive traces  301  and “valleys”  309  between the conductive traces  301 . Therefore, the surface insulating layer  305 , which is the lamination surface  307  in this embodiment, is not perfectly smooth. 
     The flexible material  103  need not be a continuous sheet, and may have cutouts, slits, or other characteristics that allow the flexible material  103  to be conformed to a curved surface.  FIGS. 4A-4E  illustrates various forms of the flexible materials  103 , such as flexible circuit boards, and curved surfaces. 
       FIG. 4A  illustrates an exemplary curved surface for a sensor array according to embodiments of this invention. A typical flex circuit sensor array applied to the inside of this surface may tend to wrinkle, buckle, or snap. 
       FIG. 4B  illustrates an exemplary “butterfly” pattern for a sensor array according to another embodiment of the invention. This pattern can be formed using a flat array and applied to a curved surface without wrinkling. 
       FIG. 4C  illustrates an exemplary two strip sensor array pattern according to yet another embodiment of this invention. 
       FIG. 4D  illustrates an exemplary three strip sensor array pattern according to yet another embodiment of this invention. Both patterns shown in  FIGS. 4C and 4D  can also be formed from a flat array and applied to a curved surface. 
       FIG. 4E  illustrates an exemplary flat sensor pattern in a “snail” pattern that can be applied to a curved surface according to yet another embodiment of this invention. 
     The above-described curved or three-dimensional shaped sensor patterns in  FIGS. 4A-4E  may be placed under or over a curved substrate, for example, a glass or plastic cover. These sensors patterns can be used in a variety of multi-touch devices, for example a multi-touch mouse. 
     In another embodiment, the sensor array can be formed on a thermal plastic substrate material that can be reformed with heat. In this configuration the sensor array may be draped across a mold and then heated to form a curved sensor array shape. Alternatively, the substrate may be vacuum formed inside a cavity. The traces in the array, which may for example be made out of copper, may be made flexible enough to withstand this type of reshaping. 
     Laminating a flexible material to a curved substrate can pose several difficulties, particularly when the process is applied in the field of electronic devices. For example, it may be more difficult to prevent air bubbles from getting trapped between a flexible material and a curved substrate during lamination than between rigid straight material. In some electronics applications, for example, laminates must meet strict quality requirements that limit the number and/or size of trapped air bubbles. If a laminate has too many trapped air bubbles, or if the air bubbles are too large, the laminate must often be discarded as defective, resulting in lost time and money. Even if the adhesive used in the defective laminate can be reworked to reduce trapped bubbles, the re-lamination process would still result in lost time. 
     In addition, the materials used in the laminates of some electronic devices can be relatively delicate. This limits the maximum pressure that can be applied during lamination. For instance, the substrate  101  in  FIG. 1A  may be glass, which is breakable under pressure. Similarly, the flexible material  103  in  FIG. 1A  may be a circuit board that can only sustain a limited amount of pressure to prevent damages to its circuit elements. 
     In view of the foregoing,  FIG. 5  illustrates a lamination system  500  according to an embodiment of the invention. Lamination system  500  includes a base  503  and an upper portion  507 . The base  503  includes a lower holder  505 . The upper portion  507  includes an upper holder  509  and control circuitry  511 . The lower holder  505  includes a lower contact surface  513  that is placed in contact with a non-lamination surface of a substrate, such as the non-lamination surface  109  of the substrate  101  in  FIG. 1A . The upper holder  509  includes an upper contact surface  515  that is placed in contact with a non-lamination surface of a flexible material, such as the non-lamination surface  111  of the flexible material  103  of  FIG. 1A . The lower holder  505  and the upper holder  509  may each be mounted to a motion block  517 ,  519 . The lower and upper motion blocks  517 ,  519  can provide various types of motion to the holders ranging from single axis motion to fully articulated motion, depending on the requirement of the particular lamination system. Different embodiments of the disclosed lamination system are described in more detail below. 
     During the lamination process, the lamination surfaces are brought together with an adhesive material in between. Various types of adhesives can be used, including pressure-sensitive adhesives (PSAs), re-workable PSAs, thermoplastic film, thermoset film, thermal cure liquid (single or multiple components), ultraviolet (UV) cure liquid, and multiple-component adhesives that cure at room temperature. The adhesive(s) may be applied to the substrate, the flexible material, or both. In addition, the adhesive(s) may be applied as a sheet or sheets, and/or one or more regions of liquid adhesive. As the lamination surfaces are brought into contact, a force-applying area of the upper contact surface  515  and a force-applying area of the lower contact surface  513  apply opposing forces to press together the substrate and the flexible material in a pressure region between the upper and lower force-applying areas. The portions of the substrate and the flexible material in the pressure region are pressed together and laminated with the adhesive material. Either or both of the lower holder  505  and the upper holder  509  may be heated to improve adhesive properties. Lamination may also be performed at or below room temperature. 
     As described in more detail in the following exemplary embodiments, the upper holder  509  and the lower holder  505  may be formed such that the pressure region may change during the lamination process. For example, in some embodiments, the pressure region changes in position during the lamination process. In other embodiments, the pressure region changes in size and/or shape during the lamination process. In still other embodiments, the pressure region changes in position and in size/shape during the lamination process. In yet other embodiments, the shape and position of the pressure region remain the same. By changing position, size, shape, and/or other aspects of the pressure region, problems such as the formation of trapped air bubbles may be minimized. 
       FIGS. 6-8  are cross-sectional views illustrating the operation of a lower holder and an upper holder of an embodiment of the disclosed lamination system. Referring to  FIG. 6 , a lower holder  601  is a base chuck formed of a rigid material, such as glass or a metal. Lower holder  601  has a lower contact surface  603  that is shaped to conform to a non-lamination surface  605  of a curved substrate  607 . An upper holder  609  is a vacuum chuck formed of a compliant material, such as rubber. The upper holder  609  has an upper contact surface  611  with vacuum holes (not shown) to hold a non-lamination surface  613  of a flexible printed circuit board (PCB)  615  in place on the upper contact surface  611 . Thus, flexible PCB  615  is forced into the shape of upper contact surface  611 . As shown in  FIG. 6 , the upper contact surface  611  initially has a higher curvature than the lower contact surface  603 . 
       FIG. 7  shows lower holder  601  and upper holder  609  during an early stage of a lamination process. Specifically, the upper holder  609  is moved along a z-axis direction towards the lower holder  601 , causing a lamination surface  701  of flexible PCB  615  to contact a lamination surface  703  of curved substrate  607  initially at a single-point, causing the lamination surfaces  701  and  703  to be pressed together in a pressure region  705  between force-applying areas  707  and  709  of the upper contact surface  611  and the lower contact surface  603 , respectively. 
     As the lamination process continues, the upper holder  609  is pressed further in the z-direction, against the lower holder  601 . The increasing pressure causes the size of the pressure region  705  to grow larger. 
       FIG. 8  shows the lower holder  601  and the upper holder  609  during a latter part of the lamination process, after upper holder  609  has been moved further along the z-axis towards lower holder  601 . Because upper holder  609  is made of a compliant material, the motion has caused the upper holder  609  to deform. Now, the contact area between the lamination surface  701  of the PCB  615  and the lamination surface  703  of the curved substrate  607  becomes greater than it was during the early stage of the lamination process shown in  FIG. 7 . The larger contact area causes the lamination surfaces  701 ,  703  to be pressed against each other in a larger pressure region  801  between larger force-applying areas  803  and  805  of the upper contact surface  611  and the lower contact surface  603 , respectively. In this embodiment, the process continues until the pressure region expands to cover the entire lamination surfaces  701 ,  703 . 
     Because the pressure region begins as a single point and expands from that point during the lamination process, surrounding air may be less likely to become trapped between the flexible PCB  615  and curved substrate  607  as a result of air being pushed out and away from the center as the process continues. Therefore, the lamination system according to this embodiment may potentially reduce or eliminate the formation of air bubbles caused during lamination. In addition, because the upper holder  609  is formed of a compliant material, the present example embodiment may be better-suited for lamination of relatively delicate materials. 
       FIGS. 9A and 9B  are cross-sectional views illustrating the operation of a lower holder and an upper holder of another exemplary lamination system according to embodiments of the invention. The system of  FIGS. 9A and 9B  is similar to the system of  FIGS. 6-8 . Referring to  FIG. 9A , the system includes a base  901  including a lower holder  903  with a lower contact surface  905 . The system also includes an upper portion, press  907 , having an upper holder  909  with an upper contact surface  911 . One difference between this embodiment (illustrated in  FIGS. 9A and 9B ) and the previous embodiment (illustrated in  FIGS. 6-8 ) is that, in this system, the upper holder  909  is a rigid chuck and the lower holder  903  is of deformable, compliant material, such as rubber. Also, the system illustrated in  FIGS. 9A and 9B  includes retractable alignment pins  913  protruding from the lower holder  903 , and vacuum holes  915  through both the upper and lower holders  909 ,  903 . 
     In this system, a curved substrate  917  is fixed to upper contact surface  911  by positioning the substrate over vacuum holes  915  and applying a vacuum to the holes. A flexible PCB  919  is fixed to the lower holder  903  by using the vacuum holes  915  through the lower holder  903 . The retractable alignment pins  913  provide a guide when positioning and fixing the flexible PCB  919  onto the lower holder  903 . The vacuum holes  915  keeps the flexible PCB  919  warped over the lower holder  903  before lamination. 
       FIG. 9B  illustrates the system of  FIG. 9A  during a lamination process. As in the embodiment described above, the upper holder  909  is moved along a z-axis direction towards the lower holder  903  so that the respective lamination surface of the curved substrate  917  and the flexible PCB  919  are pressed together at a pressure region that begins at a contact point  991  because the curvature of the lower holder  903  is higher than the upper holder  909 . The pressure region expands as the upper holder  909  continues to be pressed against the lower holder  903  because the lower holder  903  is made of a compliant, deformable material and deforms as it receives increasing pressure. As the pressure region expands, the retractable alignment pins  913  may be retracted and the lamination surface of the curved substrate  917  can eventually be in contact with the entire area of the lamination surface of the PCB  919 . Alternately, lower holder  903  may be moved toward upper holder  909  in the z-axis direction to achieve the same lamination result. 
       FIGS. 10A-C  are cross-sectional views illustrating the operation of a lower holder and an upper holder of another exemplary lamination system according to embodiments of this invention. The system of  FIGS. 10A-C  is similar to the system illustrated in  FIGS. 9A and 9B . Referring to  FIG. 10A , the system includes a base  1002  including a lower holder  1004  with a lower contact surface  1006 . A bottom substrate  1016  is held by the lower holder  1004  by a vacuum chuck (not shown) or mechanical features of the lower holder  1004 . The system also includes an upper portion, for example, a press  1008 . The upper portion includes an upper holder  1010 . In this embodiment, the upper holder  1010  has a flexible membrane  1012  adapted to hold a top substrate  1014  in a pre-form position. In various embodiments, the top substrate  1014  may be held by a vacuum chuck (not shown) or other mechanical features of the upper holder  1010 . The membrane  1012  may be a conformal material (e.g., silicone rubber) or a liquid or air filled sac. 
       FIGS. 10B and 10C  illustrate the system of  FIG. 10A  during a lamination process. Referring to  FIG. 10B , similar to previously disclosed embodiments, the upper holder  1010  is moved towards the lower holder  1004  so that the bottom surface of the top substrate  1014  becomes in contact with and presses against the top surface of the bottom substrate  1016 . Because the curvature of the lower holder  1004  is less than the curvature of the upper holder  1010 , the initial contact between the top substrate  1014  and the bottom substrate  1016  is made at the center of the top surface of the bottom substrate  1016 , as a result of the movement of the upper holder  1008  towards the lower holder  1004  in the z-direction. 
       FIG. 10C  illustrates the next stage in the lamination process. As the upper holder  1010  continues to exert pressure on the lower holder  1004  after the initial contact between the top substrate  1014  and the bottom substrate  1016 , the flexible membrane  1012  of the top holder starts to deform. As a result, the initial pressure point expands from the center of the top surface of the bottom substrate  1016  towards the edges of the bottom substrate  1016  until the top substrate  1014  and the bottom substrate  1016  are completely laminated to each other, as illustrated in  FIG. 10C . Because the upper holder  1010  includes a flexible membrane  1012  in this embodiment, pressure is applied evenly in all directions against the bottom substrate  1016  in the lamination process. The upper holder  1010  may also be made of other types of material that allows it to apply pressure evenly in all directions in the lamination process. Either or both of the lower holder  1004  and the upper holder  1010  may be heated to improve adhesive properties. In various embodiments, the process illustrated in  FIGS. 10A-C  can be applied in a reverse setup by rotating the illustrated system 180 degrees so that the lower holder is on top and the upper holder is at the bottom. 
       FIGS. 11A and 11B  illustrate the operation of a lower holder and an upper holder of another exemplary lamination system according to embodiments of the invention. In this system, a curved substrate  1101  is placed on a lower holder  1103  that includes fixed alignment pins  1105 . A flexible material  1109  is secured over the lower holder  1103  by placing the alignment holes  1107  on the flexible material  1109  over the alignment pins  1105 .  FIG. 11A  illustrates a first stage of a lamination operation in which an upper holder  1111  is moved along the z-axis towards the lower holder  1103 . The upper holder  1111  is mounted to the upper motion block  519  of  FIG. 5  by a motion articulator such as a gimbal  1113  (other articulators could include ball joints, hinges or other mechanical linkage) to provide articulated motion including translational and rotational motion along multiple axes. As the upper holder  1111  approaches the lower holder  1103 , a leading portion  1115  of the upper holder  1111  contacts a first area  1117  of flexible material  1109  and pushes the area  1117  towards the substrate  1101 . In various embodiments, the initial contact between the leading portion  1115  and the first area  1117  of the flexible material may be at different angles. The upper holder  1111  continues moving along the z-axis until the leading portion  1115  causes the first area  1117  of the flexible material  1109  to contact a first area  1119  of the substrate  1101 , creating a pressure region (not shown). 
       FIG. 11B  illustrates a second stage of the lamination operation. The second stage begins after the first area  1117  of flexible material  1109  contacts the first area  1119  of the substrate  1101 . In the second stage, the upper holder  1111  rotates about the y-axis until the top flat surface  1110  of the upper holder  1111  is parallel to the bottom flat surface  1120  of the lower holder as the upper holder  1111  moves towards the lower holder  1103  along the z-axis. This second stage motion causes the pressure region  1121  to change in size, shape, and/or position. How the pressure region  1121  changes may depend on several factors, such as the shapes and rigidity of the upper and lower holders  1111 ,  1103 , the type and amount of force/motion applied through the gimbal  1113  during operation, and other factors. 
       FIGS. 12A-E  each shows three top views taken along the z-axis at progressively increasing times during the second stage to illustrate the various ways in which the pressure region  1121  evolves depending on the different configurations that will now be described. In the figures, the shaded areas represent pressure region  1121 . The views are taken at times t=0 (beginning of second stage, initial contact of first area  1117  and first area  1119 ), t=1 (approximately midway through second stage), and t=2 (approximately the end of the second stage). 
     Referring to  FIG. 12A , if both holders are formed of rigid materials and have constant, single-axis curvature (i.e., cylindrical curvature as shown in  FIGS. 11A and 11B ), the curvature of upper holder  1111  is greater than the curvature of lower holder  1103 , and an even force is applied through the gimbal such that upper holder  1111  rolls across lower holder  1103  and applies a constant pressure during the second stage, then the size and shape of pressure region  1121  will remain substantially constant, but the position of pressure region  1121  will move along the lamination surfaces as shown in  FIG. 12A . 
     Referring to  FIG. 12B , if the configuration is the same as in  FIG. 12A , except that the curvature of upper holder  1111  is the same as the curvature of lower holder  1103 , the size of pressure region  1121  will increase, but the type of shape will remain roughly rectangular. As illustrated, in this embodiment, the aspect ratio of the rectangular shape will change. The position of one side  1210  of the rectangle will remain substantially fixed while the position of the opposite side  1212  will move farther away as shown in  FIG. 12B . 
     Referring to  FIG. 12C , the configuration of the lamination system is the same as in  FIG. 12A , except that one or both of the holders is formed of a compliant material and the force along the z-axis towards the lower holder  1103  is constantly increased through gimbal  1113  during the first half of the second stage and then constantly decreased during the last half of the second stage. As the result, the size of pressure region  1121  will increase in the first half of the second stage and decrease in the last half of the second stage, the shape of the pressure region  1121  remains rectangular though the aspect ratio will change, and the position will move along the lamination surfaces as shown in  FIG. 12C . 
     Referring to  FIG. 12D , the configuration of the lamination system used here is the same as in  FIG. 12A , except that both holders have constant, multi-axis curvature (e.g., curvature along the x-axis and the y-axis as shown in  FIGS. 13A and 13B ), and the upper holder  1111  has greater curvature than the lower holder  1101  in both axes. As the result, the size and shape of the pressure region  1121  remains fairly constant throughout the second stage and the position of the pressure region  1121  may change as shown in  FIG. 12D . 
     As is apparent in  FIG. 12D , the entire area of the lamination surfaces may not be exposed to the pressure region  1121  in the single pass of upper holder  1111 . This is different from the configurations of  FIGS. 12A-12C  which covers the entire lamination surfaces in a single pass. Therefore, it may be desirable to drive the upper holder  1111  through additional motion to cover the entire lamination surface. For example, the gimbal  1113  could provide an additional rotation motion around the x-axis to roll the upper holder  1111  to one side, and then provide a motion substantially reverse of the previous motion, resulting in the pressure region changes shown in  FIG. 12E . 
     In all the configurations described above, the substrate curvature is not limited to single axis (cylindrical curvature). Arbitrary multi-axis curvature may be supported by any of these configurations.  FIG. 13A  shows a variation of the lamination system of  FIG. 11A . As illustrated, both the upper holder  1302  and the lower holder  1308  have contact surfaces  1310 ,  1312  that have multi-axis curvature. In various embodiments, the curvature of the upper contact surface  1310  may or may not be the same as the curvature of the lower contact surface  1312 . As illustrated in  FIG. 13B , the curved substrate  1306  is fixed to the lower holder  1308  and substantially adapts the curvature of the lower contact surface  1312  of the lower holder  1308 . Similarly, the flexible material  1304  may conform to the curvature of the upper contact surface  1310  of the upper holder  1302 . 
       FIGS. 14A-D  illustrate the operation of a lower holder and an upper holder in a side-to-side lamination process according to another embodiment of the invention. This embodiment shares some of the features of the embodiments illustrated in  FIGS. 10A-C  and  FIGS. 11A-B . Referring to  FIG. 14A , the system includes a base  1402  including a lower holder  1404  with a lower contact surface  1406 . A bottom substrate  1416  is held by the lower holder  1404  by a vacuum chuck (not shown) or mechanical features of the lower holder  1404 . The system also includes an upper portion, for example, a press  1408 . The upper portion has affixed to it an upper holder  1410 . In this embodiment, the upper holder  1410  has a flexible membrane  1412  adapted to hold a top substrate  1414  in a pre-form position. In various embodiments, the top substrate  1414  may be held by a vacuum chuck (not shown) or other mechanical features of the upper holder  1410 . The membrane  1412  may be a conformal material (e.g., silicone rubber) or a liquid or air filled sac. As illustrated in  FIG. 14A , prior to the start of the lamination process, the press/upper holder  1408 ,  1410  and the base/lower holder  1402 ,  1406  are positioned like an open book, where the press/upper holder  1408 ,  1410  is the “book cover” and the base/lower holder  1402 ,  1406  is the rest of the book. The press  1408  and the base  1402  may or may not be in contact with each other. Both the top substrate  1414  and the bottom substrate  1416  are held on top of their respective holders  1410 ,  1404 . The left edge of the press  1408  is approximately aligned with the right edge of the base  1402  so that when the upper holder  1410  rotates counter clockwise about the y-axis, the upper substrate  1414  can be in position to make contact with the bottom substrate  1416  and become laminated to the bottom substrate  1416 . 
     Referring to  FIG. 14B , as the upper portion rotates about the y-axis, a first portion  1420  of the upper substrate  1414  initially comes into contact with a first portion  1422  of the bottom substrate  1416 . A pressure region (not shown) is formed at the initial point of contact between the first portion  1420  of the upper substrate  1414  and the first portion  1422  of the bottom substrate  1416 . After the initial contact, the upper portion continues to rotate about the y-axis, causing the pressure region to change in size, shape, and/or position. How the pressure region changes can depend on several factors, such as the shapes and rigidity of the upper and lower holders, the type and amount of force/motion applied to by the press during operation, and other factors. In various embodiments, the pressure region may change, for example, as illustrated in  FIGS. 12A-12E . 
       FIG. 14C  illustrates a stage in which the side-to-side lamination process is at approximately its halfway point where the press  1408  and the base  1402  are substantially parallel to each other and the upper holder  1410  is in contact and applying pressure to the center region of the lower holder  1404 . Because the adhesion force between the first portion  1420  of the upper substrate  1414  and the first portion  1422  of the bottom substrate  1416  is higher than the holding force between the upper holder  1410  and the upper substrate  1414 , the first area  1420  of the upper substrate  1414  in  FIG. 14B  is now detached from the upper holder  1410  and laminated to the first area  1422  of the bottom substrate. 
       FIG. 14D  illustrates the final stage of the side-to-side lamination process. As illustrated, the upper portion continues to rotate about the y-axis from where it was in  FIG. 14C . The center portion of the upper substrate  1414  is now detached from the upper holder and laminated to the center portion of the lower substrate  1416 . The pressure region has shifted beyond the center of the lower holder  1404  and reached the other side of the lower holder  1410 . This allows the upper substrate  1414  to be completely laminated to the bottom substrate  1422 . In this embodiment, pressure is applied evenly in all directions by the nature of the material that forms the membrane. 
     The system of  FIGS. 14A-D  may be overturned and the above described side-to-side lamination process may be repeated in the opposite direction to make sure that the substrates are completed laminated and rid of any air bubbles that remains between the substrates. 
       FIG. 15  illustrates the operation of an upper holder of another exemplary lamination system according to embodiments of the invention. In this system, an upper holder  1501  is substantially cylindrical and is formed of a compliant material such as rubber. For the sake of clarity, a lower holder is not illustrated.  FIG. 15  also shows a flexible material  1503  held at one end by grippers  1505 . The flexible material  1503  may include detachable tabs (not shown) to be held by the grippers in some embodiments. During a lamination operation, upper holder  1501  rolls across a non-lamination surface  1509  of the flexible material  1503  to press the flexible material  1503  and a multi-axis curved substrate  1509  together. As upper holder  1501  rolls across flexible material  1503 , the upper holder  1501  deforms to conform to the shape of the substrate  1509 . During the lamination process, the grippers  1505  may, for example, hold a fixed portion of the flexible material  1503 , such as an edge portion or the detachable tabs. In another embodiment, the grippers  1505  may slide along the surface of flexible material  1503  while providing enough resistance to reduce slack in the unattached portion of the flexible material  1503 . 
       FIGS. 16-18  illustrate the operation of a lower holder and an upper holder of another exemplary lamination system according to embodiments of the invention. Referring to  FIG. 16 , this system includes an upper holder  1601  and a lower holder  1603  that are substantially cylindrical wheels that can rotate about an axis. Note that diameter of one or both wheels may be chosen based on the curvature of the substrate  1605 . Each holder is formed of a compliant material, such as rubber, foam, a flexible air- or fluid-filled bag, etc. A curved substrate  1605  and a flexible material  1607  are fed in as the holders  1601 ,  1603  rotate in opposite directions to grab the substrate  1605  and the flexible material  1607  and pull them into a working space  1609  between the upper holder  1601  and the lower holder  1603 . In the working space  1609 , the upper holder  1601  and the lower holder  1603  exert opposing forces on the flexible material  1607  and the curved substrate  1605 , respectively, which causes the formation of a pressure region  1611  where lamination occurs. The portion of the flexible material  1607  in the working space is forced to be conformed to the upper holder  1601  and, as a result of the forces, any air bubbles between the flexible material  1607  and the curved substrate  1605  are pushed out. 
       FIG. 17  illustrates a more detailed view of the working space  1609 . In particular,  FIG. 17  shows the opposing force-applying areas  1701  and  1703  of flexible material  1701  and substrate  1703 , respectively. As seen in  FIG. 17 , it may be possible to make the pressure region  1611  a small size, which may allow for a greater pressure to be applied in the pressure region  1611  while reducing the chance of breakage of the lamination material. This may be particularly useful in the case that the lamination materials are delicate, for example, if curved substrate  1605  is made of glass.  FIG. 18  is a front view illustrating that rolling surfaces  1801  and  1803  of the upper holder  1601  and the lower holder  1603  are deformable and can conform to the shape of the laminate materials along the y-axis. 
       FIGS. 19-21  illustrate the operation of a lower holder and an upper holder of another exemplary lamination system according to embodiments of the invention. Referring to  FIG. 19 , this system includes an upper holder  1901  that is formed of a hollow, expandable bag or balloon, and a lower holder  1903  that is a rigid base. A curved substrate  1905  is placed on lower holder  1903  with a non-lamination surface of the substrate in contact with the lower holder  1903 . A flexible material  1907  is placed on the curved substrate  1905  with a non-lamination surface exposed to upper holder  1901 . A pump (not shown) is coupled to the upper holder  1901  to pump, for example, air into and out of the upper holder  1901 , so that the upper holder  1901  can be made to expand and contract. 
       FIG. 20  shows the beginning of a lamination process of the system of  FIG. 19 . The upper holder  1901 , which is not inflated, is moved along z-axis towards lower holder  1903  until the surface of upper holder  1901  pitch contact with the non-lamination surface of flexible material  1907 . Once contact is made, the upper holder  1901  stops moving in the z-axis. The pump (not shown) coupled to the upper holder is turned on to inflate the upper holder  1901  by pumping air into the upper holder  1901 . As shown in  FIG. 21 , the shape of the upper holder  1901  changes as it inflates, such that a pressure region is first formed at the point of first contact and then expands outward in a substantially radial direction towards the perimeter of the flexible material  1907 . This can cause air to be forced from the center to the perimeter of the laminate, helping to eliminate air bubbles in and/or surrounding the pressure region. 
       FIG. 22  illustrates the operation of a lower holder and an upper holder of another example lamination system according to embodiments of the invention. The system shown in  FIG. 22  is similar to the system shown in  FIGS. 19-21 . However, upper holder  1901  is inflated with gas or liquid before it is moved into contact with flexible material  1907 . Once upper holder  1901  is inflated, it is lowered into contact with flexible material  1907 . The motion continues downward after contact, deforming upper holder  1901  and creating a pressure region that increases in size from the initial contact point radially outward towards the perimeter. Note, while the upper holder  1901  is moving downward in contact with the flexible material  1907 , air or gas may or may not be pumped into or out of the upper holder  1901 . In other words, the degree of inflation of the upper holder  1901  may be increased or decreased while it is moving in contact with the flexible material  1907 . 
       FIGS. 23A-B ,  24 A-C, and  25  illustrate various example alignment structures that can be used to help align a flexible material  2301  when placing the flexible material  2301  onto a curved substrate  2303 .  FIGS. 23A-B  are perspective views showing the flexible material  2301  formed with break off tabs  2305  for alignment. In this embodiment, break off tabs  2305  extend from the periphery of the flexible material  2301  and have holes that can be fit over alignment pins (not shown) to help with alignment. In another embodiment, the holes of break off tabs  2305  can be used to visually align the flexible material  2301  by matching the holes with fiducials, markers, such as dots or X&#39;s (not shown). 
       FIGS. 24A-C  show the alignment holes  2401  in the flexible material  2301  that allow for visual alignment of the flexible material  2301  using fiducials on the substrate  2303 .  FIGS. 24A and 24B  show two different full views of the flexible material, and  FIG. 24C  shows a magnified view of a hole  2401  aligned with a fiducial  2402  on the substrate  2303 . 
       FIG. 25  shows another layout of alignment holes. As illustrated, the alignment holes  2501  in the flexible material  2301  are an opposite ends of the flexible material  2301 . 
       FIG. 26  is a perspective view illustrating a 2-step process for laminating a PCB  2605  to a curved substrate  2607 , and then laminating a stiffener to the PCB back. First, alignment holes  2601  are placed over alignment pins  2603  to align the PCB  2605  with a glass, curved substrate  2607 . The substrate  2607  is held in position against a base  2609  using vacuum holes (not shown). In a first step of a lamination process, an upper holder  2611  is moved along the z-axis in the direction towards the base  2609 . After making contact with the PCB  2605 , the upper holder  2611  continues moving towards the base  2609 . This movement causes the PCB  2605  to break away from the break away tabs  2613  and become laminated onto the substrate  2607 . 
     In a second step of the lamination process, a stiffener (not shown) is placed onto the exposed PCB  2605  surface, and pressed downward by the upper holder  2611  to be laminated to the PCB/glass laminate. The stiffener may be a rigid material with a curvature that matches the curvature of the substrate  2607 , 
       FIG. 27  is a perspective view illustrating a 1-step process for laminating a PCB  2705  to a glass curved substrate  2707 , while at the same time laminating a stiffener  2709  to the PCB back. As in the embodiment shown in  FIG. 26 , the alignment holes  2701  are placed over alignment pins  2703  to align the PCB  2705  with the glass curved substrate  2707 . The substrate  2707  is held in position against a base  2711  using vacuum holes (not shown). In this system, the stiffener  2709  is held to the upper holder  2713  by, for example, vacuum holes (not shown). In one example embodiment, the stiffener  2709  may be fit into a negative cutout of the upper holder  2713 . Therefore, as the upper holder  2713  moves downward towards the base  2711 , and the upper holder presses the PCB  2705  together with substrate  2707 , the upper holder  2713  is also pressing the stiffener  2709  together with the PCB  2705 . Therefore, only a single step (i.e., a single press and release motion) is needed to form a 3-layer laminate of the substrate  2707 , the PCB  2705 , and the stiffener  2713 . 
       FIGS. 28A-C  illustrates the operation of a lower holder and an upper holder of another exemplary lamination system according to embodiments of the invention. In particular,  FIG. 28  is one example of many possible combination methods that utilize different features, configurations and processes in the previously described embodiments. The system of  FIG. 28 , for example, combines some aspects of the system of  FIGS. 6-8  (e.g., rigid lower holder, upper holder with vacuum holes, lowering upper holder along z-axis to make contact at the center of the lower holder first) with some aspects of the system of  FIGS. 11 ,  12 , and  13 A (e.g., rigid upper holder, rolling motion of upper holder in y-axis). 
     Referring to  FIG. 28A , an upper holder  2801  having vacuum holes (not shown) that hold a flexible material  2803  is lowered along a z-axis to contact a rigid curved substrate  2805  at a center contact point. A pressure region  2807  is formed at the center contact point initially and then moved along the surface of the laminates by applying a rolling motion of the upper holder  2801 . Next, as illustrated in  FIG. 28B , as the rolling motion is applied in one direction, one end  2809  of the flexible material  2803  in the opposite direction begins to buckle and/or separate from the upper holder  2801 . Finally, as illustrated in  FIG. 28C , the upper holder  2801  rolls in the opposite direction, moving the pressure region  2807  over the buckled portion  2809  of the flexible material  2803  to complete the lamination. 
     By combining different aspects of embodiments, the pressure region causing lamination can be changed in many different ways to achieve the same lamination result. 
       FIGS. 29A-B  illustrate a post-lamination device and process according to embodiments of the invention. Referring to  FIG. 29A , an example microbead surface  2900  is shown. The microbead surface  2900  includes a body  2901  in which a plurality of springs  2903  are positioned. Springs  2903  are coupled to microbeads  2905  such that an outward (direction by arrows in  FIG. 29A ) force is applied to each microbead. The outward forces of springs  2903  are countered by a plurality of collars (not shown) that hold the microbeads  2900  within the body  2901  while allowing a portion of the microbeads  2905  to protrude from the body  2901 . Thus, the protruding portion of each microbead  2905  can apply a force that is proportional to the spring constant of its corresponding spring  2903 . 
       FIG. 29B  illustrates a post-lamination process in which the microbead surface  2950  is walked slowly over the surface of a laminate  2907 . The motion can be automatic or manual. In this example, the surface of the laminate  2907  has peaks  2909  and valleys  2911  as a result of, for example, underlying conductive traces (not shown). As the microbead surface  2900  is moved across the surface, the microbeads can potentially protrude down into a valley  2911  and push an air bubble  2913  to a perimeter of the laminate  2907 , thereby preventing air bubbles from being trapped in the laminate  2907 . In particular, the microbead surface  2900  can be formed such that, for example, the sizes of the microbeads  2905 , the distances between the microbeads  2905 , and/or the pattern created by the microbead protrusion conform to an underlying conductive trace pattern, potentially increasing the efficiency of the post-lamination process. In one embodiment, the microbeads  2905  are 1 mm to 5 mm in size and are 4 mm to 10 mm apart. 
       FIG. 30  illustrates a substrate  3201  including perforations  3203 . Perforations in either or both of the substrate  3201  and the flexible material  3203  can help air bubbles escape. 
     As one skilled in the art would readily understand after reading the disclosure herein, various aspects of the configuration of the lamination system can be adjusted to produce many different changes in the pressure region during a lamination process. The aspects of the configuration include, but are not limited to, the size and shape of the upper and lower holders, the materials used in the holders, the adhesives used, the materials to be laminated together, the different rotational motions, such as rolls, pitches and yaws, and various translational motions along different axes, the use of multiple passes, and post-lamination processes. Furthermore, any of the foregoing processes that utilize a rigid lower holder and a rigid upper holder can be used to laminate a rigid material to a rigid curved substrate. In other words, in those example embodiments, and others that one skilled in the art would readily recognize, the material that is laminated to a rigid curved substrate need not be flexible, but may be rigid. 
     In addition, any of the foregoing processes may be applied in a vacuum chamber or in ambient pressure. A compliant or spring-supported layer may be added to any of the holders not explicitly listed as compliant, particularly as a method of uniformly distributing applied forces across the substrates. Also, adjustment for alignment in axes other than the z-axis (lateral dimensions x and y, as well as yaw, pitch and roll) may be added to one or both the lower and the upper holders, particularly to facilitate alignment. Lamination by any of the foregoing methods may be followed by an autoclave process, in which individual parts may or may not be placed in vacuum bags, to increase bond quality and reduce trapped bubbles. In addition, alignment pins as shown in the figures do not represent all possible locations or configurations of alignment features. Fiducials and optically assisted alignment are also supported in the forgoing processes. 
     Although embodiments of this invention have been fully described with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of embodiments of this invention as defined by the appended claims.

Metadata:
Filing Date: 20100723
Publication Date: 20120612
Grant Date: 20120612
Priority Date: 20080507
Inventors: SUNG KUO-HUA
EDWARDS TROY J.
FEINSTEIN CASEY J.
ZHONG JOHN Z.
HOTELLING STEVEN PORTER
LAUDER ANDREW DAVID
Assignee: APPLE INC
CPC Classifications: [{"code": "B32B38/1866", "inventive": true, "first": true, "tree": "[]"}, {"code": "Y10T156/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T156/1028", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2038/047", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/03543", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B38/1858", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T156/18", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2038/047", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29C63/0073", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T156/1028", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B37/0053", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B37/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y10T156/17", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B37/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T156/1793", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T156/1793", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2037/264", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T156/17", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B37/003", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B37/003", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B38/1866", "inventive": true, "first": true, "tree": "[]"}, {"code": "B32B37/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T156/18", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B37/0053", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2457/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2037/264", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B38/1858", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29C63/0073", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2457/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T156/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "B29C63/0047", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B37/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03543", "inventive": true, "first": false, "tree": "[]"}, {"code": "B29C63/0047", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B17/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B17/10", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 40940606