PATENT DOCUMENT

Publication Number: US-9069525-B2
Application Number: US-201414321533-A
Country: US
Kind Code: B2

Title: Methods for fabricating display structures

Abstract:
An electronic device display may have a color filter layer and a thin film transistor layer. A layer of liquid crystal material may be interposed between the color filter layer and the thin film transistor layer. A layer of polarizer may be laminated onto the surface of the color filter layer. Laser trimming may ensure that the edges of the polarizer are even with the edges of the color filter layer. The thin film transistor layer may have an array of thin film transistors that control pixels of the liquid crystal material in the display. Driver circuitry may be used to control the array. The driver circuitry may be encapsulated in a planarized encapsulant on the thin film transistor layer or may be mounted to the underside of the color filter layer. Conductive structures may connect driver circuitry on the color filter layer to the thin film transistor layer.

Claims:
What is claimed is: 
     
       1. A computer, comprising:
 a housing structure; and 
 a display in the housing structure that includes:
 a color filter layer; 
 driver circuitry comprising at least an integrated circuit mounted on the color filter layer; 
 a thin-film transistor layer; 
 an opaque layer formed in a border around a periphery of the display and extending beyond a pixel area of the display that blocks inactive peripheral portions of the display from view; 
 an opening in the opaque layer located beyond the pixel area of the display; and 
 a camera in the housing structure that receives light through the opening in the opaque layer. 
 
 
     
     
       2. The computer of  claim 1 , wherein the opening is at least one of circular or rectangular. 
     
     
       3. The computer of  claim 1 , further comprising a polarizer layer. 
     
     
       4. The computer of  claim 3 , wherein the polarizer layer includes a polarizer layer opening that aligns with the opening in the opaque layer. 
     
     
       5. The computer of  claim 4 , wherein the polarizer layer opening is filled with an epoxy fill. 
     
     
       6. The computer of  claim 5 , wherein the epoxy fill comprises an ultraviolet curable epoxy. 
     
     
       7. The computer of  claim 5 , wherein a surface of the epoxy fill is vertically aligned with a planar outer surface of the polarizer layer. 
     
     
       8. The computer of  claim 5 , wherein a surface of the epoxy fill is co-planar with an outer surface of the polarizer layer. 
     
     
       9. The computer of  claim 3 , further comprising adhesive attaching a portion of the polarizer layer to the color filter layer. 
     
     
       10. The computer of  claim 3 , further comprising an antireflection coating layer. 
     
     
       11. The computer of  claim 10 , wherein the antireflection coating layer is laminated onto a surface of the polarizer layer. 
     
     
       12. The computer of  claim 10 , wherein edges of the antireflection coating layer are aligned with edges of the color filter layer. 
     
     
       13. The computer of  claim 9 , wherein the polarizer layer includes multiple polarizer layer openings. 
     
     
       14. The computer of  claim 13 , wherein one of the multiple polarizer layer openings aligns with the opening in the opaque layer. 
     
     
       15. The computer of  claim 3 , wherein an outer surface of the polarizer layer is smooth and even. 
     
     
       16. The computer of  claim 3 , wherein a portion of the polarizer layer is laminated to the color filter layer. 
     
     
       17. The computer of  claim 3 , wherein edges of the polarizer layer are aligned with edges of the color filter layer. 
     
     
       18. The computer of  claim 1 , wherein the color filter layer does not include a color filter layer opening aligned with the opening in the opaque layer. 
     
     
       19. The computer of  claim 1 , wherein the opaque layer is formed in the border around a periphery of the color filter layer. 
     
     
       20. A display structure, comprising:
 a color filter layer; 
 driver circuitry comprising at least an integrated circuit mounted on the color filter layer; 
 a thin-film transistor layer; 
 an opaque layer formed in a border around a periphery of the display and extending beyond a pixel area of the display that blocks inactive peripheral portions of the display from view; 
 an opening in the opaque layer located beyond the pixel area of the display; and 
 a camera that receives light through the opening.

Description:
This application is a continuation of patent application Ser. No. 13/249,828, filed Sep. 30, 2011, which is a continuation of patent application Ser. No. 12/691,715, filed Jan. 21, 2010, which claims the benefit of provisional patent application No. 61/259,989, filed Nov. 10, 2009, all of which are hereby incorporated by reference herein in their entireties as if fully disclosed herein. 
    
    
     BACKGROUND 
     This invention relates to electronic devices and, more particularly, to display structures for electronic devices such as portable computers. 
     Portable computers typically have upper and lower housing portions that are connected by a hinge. The lower housing portion contains components such as printed circuit boards, disk drives, a keyboard, and a battery. The upper housing portion contains a display. When the computer is in an open configuration, the upper housing portion is vertical and the display is visible to the user of the portable computer. When the computer is closed, the upper housing lies flat against the lower housing. This protects the display and keyboard and allows the portable computer to be transported. 
     Portable computer displays that are based on liquid crystal display technology include layers of polarizer. The outermost polarizer layer is generally formed on the outer surface of a color filter glass layer. The polarizer layer often has dimensions that are slightly larger than the color filter glass. Use of an oversized polarizer of this type helps to ensure that the color filter glass layer is completely covered with polarizer. However, the overhanging edges of the oversized layer of polarizer can give rise to reliability problems when the display is used in a product. As a result, undersized polarizer layers are sometimes used. With this approach, the size of the polarizer is chosen so as to be smaller than the dimensions of the color filter glass. Overlapping polarizer edges are avoided, but a peripheral region on the surface of the color filter glass is uncovered. This uncovered region can be unsightly unless hidden from view by a bezel. Use of a large bezel, in turn, may not be aesthetically appealing, particularly in modern devices. 
     It would therefore be desirable to be able to produce improved displays for electronic devices. 
     SUMMARY 
     An electronic device display such as a computer may have a housing. A display may be mounted in the housing. The display may have a color filter layer and a thin film transistor layer. A layer of liquid crystal material may be interposed between the color filter layer and the thin film transistor layer. A layer of polarizer may be laminated onto the surface of the color filter layer. Laser trimming may ensure that the edges of the polarizer are even with the edges of the color filter layer. A shim may be used to help prevent the polarizer layer from adhering to the color filter layer in certain regions. Using laser trimming, the edges of the shim may be traced to cut an opening in the polarizer. The opening may be used to form a camera window for a camera module. 
     The thin film transistor layer may have an array of thin film transistors that control pixels of the liquid crystal material in the display. Driver circuitry may be used to control the array. The driver circuitry may be encapsulated in a planarized encapsulant on the thin film transistor layer or may be mounted to the underside of the color filter layer. Ink-jet-printed conductive structures may connect driver circuitry on the color filter layer to the thin film transistor layer. A layer of black or non-black ink may be interposed between the driver circuitry and the color filter layer to which the driver circuitry is mounted. 
     Further features of the invention, its nature and various advantages will be mere apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative portable computer with display structures in accordance with an embodiment of the present invention. 
         FIG. 2  is a cross-sectional side view of illustrative display structures in an electronic device such as a portable computer in accordance with an embodiment of the present invention. 
         FIGS. 3 ,  4 ,  5 , and  5  are cross-sectional side views of display structures such as a color filter glass layer and thin film transistor glass layer on which driver circuitry has been formed during successive stages of fabrication in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of display structures in which driver circuitry has been mounted on an underside of a color filter glass layer in accordance with an embodiment of the present invention. 
         FIG. 6  is a top view of a conventional thin film transistor glass layer showing how driver integrated circuits and traces may be formed on the thin film transistor glass layer. 
         FIG. 9  is a bottom view of a color filter glass layer of the type shown in  FIG. 1  showing how underside traces on the color filter glass layer may be used to connect driver integrated circuits to vertical connection structures such as ink-jet-printed conductive dots in accordance with an embodiment of the present invention. 
         FIG. 10A  is a top view of a mother glass panel on which structures for multiple displays have been formed in accordance with an embodiment of the present invention. 
         FIG. 10B  is a top view of a section of glass that contains multiple displays that have been cut from the mother glass panel of  FIG. 10A  in accordance with an embodiment of the present invention. 
         FIG. 10C  is a top view of display structures for an individual display that have been cut from the glass piece of  FIG. 10B  in accordance with an embodiment of the present invention. 
         FIG. 10D  is a top view of the display structures of  FIG. 10C  following lamination of an oversized polarizer layer in accordance with an embodiment of the present invention. 
         FIG. 10E  is a side view of an illustrative laser cutting tool that may be used to trim excess polarizer material from the edges of the display structures after the polarizer material has been attached to the display structures as shown in  FIG. 10D  in accordance with an embodiment of the present invention. 
         FIG. 10F  is a cross-sectional view of the display structures taken along line  103 - 103  of  FIG. 10D  prior to laser removal of a circular shim layer in accordance with an embodiment of the present invention. 
         FIG. 10G  is a top view of the display structures after laser edge trimming and laser shim removal operations have been completed in accordance with an embodiment of the present invention. 
         FIG. 11  is a flow chart of illustrative steps involved in forming display structures for an electronic device in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     An illustrative electronic device such as a portable computer in which display structures may be provided is shown in  FIG. 1 . As shown in  FIG. 1 , portable computer  10  may have housing  12 . Housing  12 , which is sometimes referred to as a case, may be formed from one or more individual structures. For example, housing  12  may have a main structural support member that is formed from a solid, block of machined aluminum or other suitable metal. One or more additional structures may be connected to the housing  12 . These structures may include, for example, internal, frame members, external coverings such as sheets of metal, etc. Housing  12  and its associated components may, in general, be formed, from any suitable materials such as such as plastic, ceramics, metal, glass, composites, etc. An advantage of forming housing  12  at least partly from metal is that metal is durable and, attractive in appearance. Metals such as aluminum may be anodized to form an insulating oxide coating. 
     In general, the components of portable computer  10  can be formed from any suitable materials. As examples, the components of portable computer  10  may be formed from materials such as metals (e.g., aluminum, stainless steel, alloys of metals, electroplated metals, plated and other coated metals, etc.), plastics (e.g., polycarbonate (PC) plastics, acrylonitrile butadiene styrene (ABS) plastics, thermoplastics, PC/ABS plastic blends, etc.), composite materials (e.g., carbon fibers or other fibers bound by a binder such as a polymer resin), plastics that have been injection molded around metal structures, laminated plastic layers, ceramics, metal, glass, composites, metal-filled epoxy, other suitable materials, and combinations of these and other materials. Components of portable computer  10  which are described herein as being formed from one or more specific materials (e.g., housing  12  which is sometimes described herein as being formed from machined aluminum as an example) can be formed from any of the above-mentioned materials, other suitable materials, or combinations of such materials. 
     Housing  12  may have an upper portion  26  and a lower portion  28 . Lower portion  23  may be referred to as the base or main unit of computer  10  and may contain components such as a hard disk drive, battery, and main logic board. Upper portion  25 , which is sometimes referred to as a cover, lid, or display housing, may rotate relative to lower portion  28  about rotational axis  16 . Portion  18  of computer  10  may contain a hinge and associated clutch structures and is sometimes referred to as a clutch barrel. 
     Lower housing portion  28  may have a slot such as slot  22  through which optical disks may be loaded into an optical, disk drive. Lower housing portion may also have a touchpad such as touchpad  24  and may have keys  20 . If desired, additional components may be mounted to upper and lower housing portions  26  and  28 . For example, upper and lower housing portions  26  and  28  may have ports to which cables can be connected (e.g., universal serial bus ports, an Ethernet port, a Firewire port, audio jacks, card slots, etc.). Buttons and other controls may also be mounted to housing  12 . Speaker openings such as speaker openings  30  may be formed in lower housing portion  26  by creating an array of small openings (perforations) in the surface of housing  12 . 
     A display such as display  14  may be mounted within upper housing portion  26 . Display  14  may be, for example, a liquid crystal display (LCD), organic light emitting diode (GLSD) display, or plasma display (as examples). Display  14  may contain a number of layers of material. These display structures may include, for example, layers of optically transparent materials such as plastic and glass. Layers of plastic and optical adhesive may also be incorporated into display  14 . In a liquid crystal display, which is sometimes described herein as an example, a layer of liquid crystal material may be formed between a color filter glass layer and a thin film transistor glass layer. The thin film transistor glass layer may include an array of thin film transistors. The transistors may drive the image pixels in the display. The color filter glass may be used to impart colors to the pixels. Layers of polarizer may be formed above and below the color filter glass and the chin film transistor glass. Display structures in display  14  may also include backlight structures such as a reflective sheet, a light guide panel, and layers of optical films such as diffuses layers and light collimating layers. 
     Computer  10  may have input-output components such as touch pad  24 . Touch pad  24  may include a touch sensitive surface that allows a user of computer  10  to control computer  10  using touch-based commands (gestures). A portion of touchpad  24  may be depressed by the user when the user desires to “click” on a displayed item on screen  14 . 
     A cross-sectional side view of a portion of upper housing  26  of device  10  ( FIG. 1 ) in which display structures  106  have been mounted. In general, display structures  106  may be formed from any suitable materials (e.g., plastic, glass, other optically suitable materials, etc). Upper housing  26  may, for example, be formed from machined aluminum. If desired, upper housing  26  may be formed from other suitable materials such as plastics, composites, etc. Elastomeric gasket  104  may be used to provide a soft interface between potentially fragile glass layers in structures  106  and housing  26 . 
     Display structures  106  may produce an image using any suitable display technology (e.g., light-emitting diodes such as an array of organic light-emitting diodes, liquid crystal display pixels, plasma-based pixels, etc.). An arrangement in which display structures  106  are based on liquid crystal display (LCD) technology is sometimes described herein as an example. The use of LCD structures in display structures  106  is, however, merely illustrative. Display structures  106  may, in general, be formed, from any suitable type of display structures. Moreover, use of displays structures  106  in portable computers and other electronic devices with upper and lower housings is merely illustrative. Display structures  106  may be used in a handheld electronic device, a television, a tablet computer, a desktop computer monitor, or ether electronic equipment. 
     As shown in  FIG. 2 , display structures  106  may have an upper polarizer layer  102  and a lower polarizer layer  96 . Layers such as layers  102  and  96  may be formed from one or more sublayers. For example, layer  102  may include an antireflection coating layer, a stretched plastic layer that forms the active polarizer portion of layer  102 , a polymer compensation layer, etc. Light guide structures  88  may provide backlight for structures  106 . Light-guide structures  68  may include reflective structures such as reflective sheet  90  (e.g., white polyester), light-guide panel  92 , and optical films  94 . Optical films  94  may include a diffuses layer and light collimating layers (as an example). If desired, light reflection functions may be provided by housing  26 . Housing  26  may be formed from a reflective material such as metal and/or the interior surfaces of housing  26  may be coated with a reflective coating such white paint or ink, silver paint or ink, a reflective material such as chromium, etc. In arrangements in which housing  26  is highly reflective, some or all of reflective sheet  90  may be omitted. 
     Clearances D2 and D1 help prevent damage to display structure  106  during use of device  110 . In a typical arrangement, clearance D2 may be about 1.2 to 1.8 mm and clearance D1 may be about 0.11 mm. End clearance D3 may be about 0.3 mm. 
     Light from a light-emitting diode array or other backlight source is provided to an edge of light guide panel  92 . Panel  92  and the other structures in light guide structures  68  direct this light upwards in direction  108  through thin film transistor layer  98  and color filter layer  100 . 
     Thin-film transistor substrate glass layer  98  may contain thin-film transistors in array  110 . Color filter glass layer  100  may contain an array of optical filters of different colors to provide display structures  106  with the ability to display color images. Color filter layer  100  may be formed from glass into which dye of different colors has been impregnated, from a glass layer coated with a pattern of colored dye, from a glass or plastic layer that is covered with a pattern of thin colored filter structures (e.g., filters formed from polymer or glass containing dye), or any other suitable color filter structures. A ground plane structure such as ground plane  111  may be formed on the lower surface of color filter layer  100 . Ground plane  111  may, for example, be formed from a rectangular thin film of indium tin oxide or other transparent conductive material. Liquid crystal layer  112  may be controlled by the electric fields produced between the thin-film transistors of array  110  and ground plane  111 . 
     Display structures  106  may, if desired, be covered by a layer of cover glass. The cover glass layer adds bulk to device  10 , so when size and weight are to be minimized, the cover glass may be omitted as shown in  FIG. 2 . A cosmetic trim structure such as a bezel may cover the edge of display structures  106  (e.g., in the vicinity of gasket  104 ) or, as shown in  FIG. 2 , the display for device  10  may be implemented without a bezel to minimize the thickness of the non-display structures at the edge of housing  26 . 
     Color filter layer  100  may be formed of a durable clear layer (e.g., a strong glass or plastic) that resists damage from contact. Anti-scratch coatings may also be provided on the surface of color filter layer  100  (e.g., as part of polarizer layer  102  or above polarizer layer  102 ). 
     To hide the peripheral portions of display structures  106  that lie along the outer edges of display housing  26  from view, an opaque material such as ink layer  114  may be incorporated around the periphery of display structures  106  to form a border. Opaque layer  114  may be formed on the underside of color filter layer  100  or on the upper surface of thin-film transistor plans layer  98  (as examples). The opaque material may have any suitable color (e.g., black, grey, silvery white, blue, red, etc.). 
     With the arrangement of  FIG. 2 , color filter layer  100  and thin-film transistor layer  38  extend outwardly (in the leftward direction in the orientation of  FIG. 2 ) so as to form an overhanging portion  116  that is supported by the matching ledge in housing  26 . If desired, only color filter layer  100  may extend in this way (e.g., so that the overhanging portion of layer  100  rests on the lodge formed by housing  26 ). In this type of arrangement, the thin-film transistor layer may extend only as far as light-guide structures  68  of  FIG. 2 . If desired, portions of gasket  104  may be interposed between display structures  106  and housing  26  in region  116 , as illustrated by protruding lower lip portion  105  of gasket  104  in the example of  FIG. 2 . Display driver circuitry  118  may, if desired, be formed in region  116  (e.g., as part of thin film transistor layer  98  or in a chip mounted on thin film transistor layer  98  or color filter layer  100 ). 
     As shown in  FIG. 2 , edge  120  of polarizer layer  102  and edge  122  of color filter layer  100  may be laterally aligned (i.e., these edges may be placed at the same lateral distance along dimension  126  so that they are even with each other and are horizontally aligned at vertical axis  124 ). Edge  120  and edge  122  may, for example, be aligned, within a lateral tolerance of 100 microns or less, 50 microns or less, or 25 microns or less. Edge  125  of thin film transistor glass layer  98  may also be aligned at axis  124 . When polarizer layer  102  is aligned with the underlying glass layers in this way, the outer surface of display  14  has an attractive appearance and potential, reliability issues that might arise in using an oversized polarizer layer may be avoided. 
     Minimal overlap between polarizer layer  102  and color filter layer  100  may be obtained using a trimming operation. With one suitable arrangement, which is sometimes described herein as an example, trimming operations may be implemented using a computer-controlled laser trimming tool. 
     Polarizes layer  102  may be attached to the planer outer surface of color filter layer  100  using any suitable technique. For example, polarizer layer  102  may be laminated onto the surface of color filter layer  100  using pressure sensitive adhesive. A roller or other tool may be used to press the polarizer layer onto the color filter layer with sufficient force to activate the adhesive. 
     Driver circuitry  118  of  FIG. 2  may be implemented using integrated circuits. These integrated circuits may be mounted on the upper surface of thin film transistor layer  98  or on the underside of color filter glass  100 .  FIGS. 3 ,  4 ,  5 , and  6  are cross-sectional side views of some of the display structures of  FIG. 2  showing how driver circuits  118  may be mounted on thin film transistor layer  99  and covered with a planarized layer of encapsulant. 
     Initially, no color filter layer may be attached to thin film transistor layer  98  ( FIG. 3 ). 
     Following attachment of color filter layer  100  (e.g., using pressure sensitive adhesive) and driver circuits  100 , thin film transistor layer  98  may appear as shown in  FIG. 4 . Driver circuits  100  may be formed near the edge of thin film transistor layer  98 , so as not to obstruct any of the main central viewing area of display  14 . In a typical arrangement, there may be two or more thin film transistor array driver circuits  118 , each of which is located at a different position along the edge of thin film transistor layer  98  (i.e., at locations that are further into the page in the orientation of  FIG. 4 ). Integrated circuits  118  may be connected to the thin film transistors in thin film transistor layer  98  using solder and conductive traces. 
     After transistor array driver circuitry  118  has been formed on thin film transistor layer  98 , an encapsulating material such as encapsulant  126  may be deposited on top of circuitry  118  and planarized, as shown in  FIG. 5 . Encapsulating material  126  may be formed from thermally cured epoxy, ultraviolet-light-cured epoxy, other adhesives, plastics, glasses, etc. Planar station operations may be performed by mechanical polishing or using a combination of chemical and mechanical polishing (CMP) (as examples). Once planarized, upper planar surface  128  of encapsulant  126  and upper planar surface  130  of  FIG. 5  will typically lie in the same plane, as shown in  FIG. 5 . Co-planarity of planar surface  128  and planar surface  130  may also be obtained by accurately controlling the height and flatness of surface  128  during fabrication (e.g., by using a mold, by controlling the amount of material that is deposited, etc.). 
     Following formation of planarized encapsulant  126 , polarizer layer  102  may be laminated onto the surface of encapsulant  126  and color filter layer  100 , as shown in  FIG. 6 . Trimming operations may be performed to ensure that the edges of polarizer  102  are aligned with the edges of color filter glass  100  (on edges such as the right hand edge in  FIG. 6 ), the edges of encapsulant  126  (i.e., the left edge of  FIG. 6 ). In the configuration of  FIG. 6 , the edges of polarizer layer  102  are also aligned with the edges of thin film transistor layer  98 . 
     If desired, thin film transistor array driver circuits  118  may be mounted on the lower surface of color filter layer  100 . This type of arrangement is shown in  FIG. 7 . As shown in  FIG. 7 , driver circuit  118  may be mounted on a layer of ink such as ink  114 . Ink  114  may block driver circuit  118  from view in direction  131 . Integrated circuit  118  may be connected to conductive structure  130  by conductive traces  132 . Ground plane  111  may be formed on the lower surface of color filter layer  100 . Ground plane  111  may be, for example, a layer of transparent conductive material such as indium tin oxide. During operation, driver circuits  118  supply control signals to thin film transistor array  110  on the surface of thin film transistor substrate  98 . Electric fields are produced between the circuits in array  110  and ground plane  111 . These fields control the state of individual pixel regions in liquid crystal layer  112 . 
     Ground planer  111  may be grounded using conductive structures such as structures  128 . In conventional liquid crystal displays, structures  128  are applied to the lower surface of color filter layers by applying drops of liquid using ink jet printing. When the liquid solidifies, conductive vertical structures are formed to short ground plane  111  to transistor array  110 . 
     As shown in  FIG. 7 , conductive structures  130  may be used, to interconnect circuitry  118  on color filter layer  100  wish circuitry  110  on thin film transistor layer  98 . Conductive structures  130  may be formed using the same type of process that is used to form structures  128  or using a different process. Techniques that may be used to form structures  130  include painting (e.g., applying silver paint with a brush or pad), screen printing, pad printing, using a nozzle or dropper to deposit drops of liquid precursor-material ouch as metal-filled epoxy, sputtering, electrochemical deposition, plating, ink-jet coating, other suitable techniques, and combinations of these techniques. With one suitable arrangement, which is sometimes described herein as an example, an ink-jet printer is used to deposit a liquid such as metal-filled epoxy to form a desired pattern of structures  130  onto the underside of color filter layer  100 . This process may also be used to deposit structures  128 . 
     Once deposited on color filter layer  100 , color filter layer  100  and thin film transistor layer  98  may be attached to each other to encapsulate liquid crystal layer  112 . When attached in this way, the circuitry of driver circuits  118  is connected to thin film transistor array circuitry  110  via traces  132  and structures  130 . 
     In conventional displays, thin film transistor driver integrated circuits  134  are connected to the thin film transistor array on thin film transistor glass  138  using conductive traces  136  on thin film transistor glass  138 , as shown in  FIG. 8 . 
     With an arrangement, of the type shown in  FIG. 7 , traces  132  on the surface of color filter layer  100  may be used in routing thin film transistor array signals from driver integrated circuits  118  to thin film transistor array  110 . This is illustrated in more detail in the top view of  FIG. 9 . As shown in  FIG. 9 , traces  132  may form at least some of the routing functions that would conventionally be handled using traces  136  of  FIG. 6 . After passing vertically through conductive structures  130 , these can be handled using corresponding routing lines in circuitry  110  on thin film transistor layer  98  ( FIG. 7 ). 
     Assembly techniques that may be used for forming display structures such as the display structures of  FIGS. 6 and 7  are illustrated in the diagrams of  FIGS. 10A-10G . 
     In a typical manufacturing process, structures for multiple displays are initially formed in parallel on a relatively large sheet of “mother glass.” As shown in  FIG. 10A , mother glass  142  may contain multiple copies of color filter glass  100 . 
     Mother glass  142  may be quartered to form smaller panels such as panel  144  of  FIG. 10B . 
     As shown in  FIG. 10C , a cutting tool such as tool  119  may be used to cut an individual color filter glass layer  100  from panel  144  of  FIG. 10B  (or, if desired, directly from mother glass  142  of  FIG. 10C ). Cutting tool  149  may use a laser, saw, or other computer-controlled cutting mechanism for cutting color filter glass  100  from panel  144  or glass  142 . With one suitable arrangement, cutting tool  149  may be implemented using a multi-head free-shape diamond scriber. A scriber or other such tool may be used to create cuts with curved, sections such as curved corners  148  in color filter layer  100  of  FIG. 10C . 
     As shown in  FIG. 10C , color filter layer  100  may be provided with a fiducial such as fiducial  146 . This allows camera-based automatic alignment systems to be used when handling color filter layer  100  during processing. Fiducial  146  may be implemented be forming one or more metal alignment marks on the surface of layer  100  (as an example). 
     After forming a color filter glass layer of a desired shape, polarizer layer  102  may be laminated onto the surface of the color filter glass layer ( FIG. 10D ). As shown in  FIG. 10D , the lateral dimensions of polarizer layer  102  may be chosen so as to be slightly larger than the corresponding lateral dimensions of color filter layer  100  (i.e., polarizer layer  102  may be oversized relative to color filter layer  100 ). With this type of arrangement, there is a slight overlap (overhang) in the polarizer layer  102  around the peripheral edge portion of the polarizer layer. The polarizer layer may include multiple layers of material (e.g., an antireflection coating layer, an active polarizer layer, a compensation layer, etc.) or some or all of these layers may be formed during separate lamination steps. Lamination may be performed using lamination tool  151 . With a typical arrangement, lamination tool  151  presses downwards on the surface of color filter layer  100  using rollers. Pressure sensitive adhesive on the underside of polarization layer  102  attaches polarization layer  102  to the upper surface of color filter layer  100 . 
     Following lamination of oversized polarization layer  102  onto the surface of color filter glass layer  100 , excess polarizer may be removed. In particular, a trimming tool may be used to cut away undesired portions of the polarizer layer. The trimming tool may be based on blade-type cutters, saws, press cutting equipment, or other suitable trimming equipment. With the illustrative arrangement of  FIG. 10E , trimming equipment has been implemented using a laser such as laser  156 . Laser  156  may be a diode laser, a gas laser, a glass laser, a continuous-wave laser, a pulsed laser, or any other suitable type of laser. With one suitable arrangement, laser  156  is a carbon dioxide laser that produces infrared light. Infrared light is absorbed by polarizer layer  102 , which facilitates efficient cutting operations. 
     The position of laser beam  157  may be controlled using controllable mirrors such as mirror  159  and/or by controlling the position of the workpiece (i.e., polarizer  102 , adhesive  168 , and color filter layer  100 ) using translation stages such as translation stage  158 . Camera  152  may be used to capture images of the workpiece and, using images of fiducial  146  ( FIG. 10C ), may assist in aligning the workpiece relative to beam  17 . Control unit  154  may control laser trimming operations by controlling the power of laser  156 , by controlling the image acquisition functions of camera  152 , by controlling the position of beam  157  (e.g., by controlling mirror  159  and/or translation stage  158  or other positioning equipment), etc. As polarizer  102  is trimmed, excess pieces of polarizer such as piece  102  of  FIG. 10E  may be removed from the workpiece. 
     Trimming operations may be used to remove pieces of overhanging polarizer along the edges of color filter glass layer  100  so that the edges of polarizer  102  are accurately aligned with the edges of layer  100  (i.e., within a tolerance 100 microns or less, within 50 microns or less, etc.). Trimming operations may also be used to remove portions of polarizer  102  elsewhere on color filter layer  100 . For example, trimming operations may be used to remove a circular piece of polarizer  102  to form a window opening for a camera. 
     Peripheral pieces of polarizer  102  overhang the edges of color filter layer  100  and are therefore not attached to any other structures. During trimming, peripheral pieces of polarizer such as piece  102 ′ of  FIG. 10E  are therefore not generally difficult to remove from the workpiece. Unless care is taken, however, the use of adhesive  168  to attach polarizer  102  to the surface of color filter layer  100  can make it challenging to remove other trimmed portions of polarizer  102 . 
     One way to facilitate the removal of trimmed pieces of polarizer  102  from color filter layer  100  involves the introduction of harrier layer material under selected portions of adhesive  168 . The barrier layer material may be formed from a liquid (e.g., water, solvent, oil, or other substances) or a solid (e.g., plastic, metal, glass, etc.). In areas where the barrier layer material is present, adhesive  168  is prevented from adhering effectively to the upper surface of color filter layer  100 , thereby facilitating subsequent removal of the portion of polarizer that lies above the barrier layer material. 
     If desired, barrier layer structures may be provided in the form of thin layers of plastic (“shims”). An example of this type of arrangement is shown in the cross-sectional, side view of  FIG. 10F . During the lamination process, ( FIG. 10D ), adhesive  166  may be formed on the underside of polarizer  102  (e.g., by spray coatings using a roller, etc.). Before laminating polarizer  102  onto the surface of color filter layer  100 , shim  160  (or other suitable barrier layer structure) may be attached to the underside of polarizer  102 . Shim  160  may, for example, be placed in contact with adhesive  168  in a location at which it is desired to form an opening in polarizer  102 . After shim  160  has been placed on this portion of adhesive  168 , lamination tool  151  may laminate polarizer  102  (and the attached shim) onto the surface of the color glass layer to form an arrangement of the type shown in  FIG. 10F . Laser trimming equipment of the type shown in  FIG. 10E  may be used, to cut through polarizer  102  around the periphery of shim  160  (shown as edge locations  162  in  FIG. 10F ). To avoid damaging shim  160 , laser light may be focused adjacent to—but just beyond—the outer edges of shim  106  during trimming. 
     After the laser cut along the edge of shim  160  has been made, portion  164  of polarizer  102  will be attached only to shim  160  and not to the remaining polarizer on color filter layer  100 . Portions  156  of polarizer  102  are attached to color filter layer  100  by adhesive  168 , so portions  166  will remain in place following trimming. Shim  160  is not attached to color filter layer  100  by adhesive, so shim  160  and portion  164  may be removed from the workplace. The shape of shim  160  and the shape of the corresponding laser cut in polarizer  102  that is used to liberate shim  160  and portion  164  may be circular, rectangular, etc.  FIG. 10G  is a view of the upper surface of color filter layer  100  after a circular shim  160  has been removed from color filter layer  100  to form circular camera hole  150 . Once color filter layer  100  has been assembled to form a complete display, a camera module may be mounted behind hole  150 . 
     In arrangements in which a layer of ink is formed around the periphery of the color filter layer to block components from view, the portion of the ink layer that lies behind the hole may be omitted to ensure that the camera module will not be blocked by ink. Because no polarizer  102  is present in the opening, camera operation is not adversely affected by the presence of polarizer. 
     Although formation of a single opening is illustrated in  FIGS. 10A-10G , any suitable number of polarizer openings may be formed if desired. Moreover, additional layers of films may be laminated and trimmed in the same way. For example, an antireflection coating layer may be laminated onto the surface of polarizer  102  (e.g., in a situation in which polarizer layer  102  does not already contain an antireflection coating layer). 
     Illustrative steps involved in forming display structures for device  10  are shown in  FIG. 11 . 
     At step  170 , display structures (e.g., color filters) may be fabricated as part of mother glass  142  of  FIG. 10A . 
     After forming the color filter mother glass, the mother glass may optionally be divided into smaller panels (e.g., mother glass  142  may be quartered to form panels such as panel  144  of  FIG. 10B ). 
     At step  172 , cutting tool  143  (e.g., a diamond, scribing tool) may be used to cut an individual piece of color filter glass from mother glass  142  or panel  144  (i.e., layer  100  of  FIG. 10C ). 
     At step  176 , adhesive barrier structures such as shim  160  may be attached to the underside of adhesive layer  166  and associated polarizer layer  102  and the resulting masked polarizer layer may be laminated onto the upper surface of color filter layer  100  using lamination tool  151 . 
     At step  178 , laser trimming equipment of the type described in connection with  FIG. 10E  or other suitable cutting equipment may be used to remove the overlapping edges of polarizer  102  and may be used to cut out shim  160  to form opening  150 . Because laser trimming is used to trim away excess edge portions of polarizer  102 , the edges of polarizer  102  may be accurately aligned with the edges of color filter glass  100 . Following trimming operations to remove the peripheral edge portions of the oversized polarizer layer, the edges of the polarizer will be even with the edges of the color filter glass layer. Because of the use of shim  160  or other such adhesive barrier materials, adhesive  168  is prevented, from adhering to areas of color filter layer  100  where polarizer openings are desired. 
     As illustrated by step  180 , some or all of the operations of steps  170 ,  172 ,  174 ,  176 , and  178  may be repeated as desired (e.g., to add additional layers of material such as antireflection coating layers that have edges that are aligned with the edges of color filter glass  100 ). If desired, planarization operations may be performed to help ensure that the top surface of each layer is planar before subsequent layers are laminated. For example, if a circular hole has been formed in the polarizer layer and if is desired to deposit a separate antireflection layer, a liquid such as ultraviolet curable epoxy or other planar luring substance may be deposited into the circular hole. This planarizing substance can foe used to fill the circular hole (i.e., by filling the hole sufficiently that the upper surface of the epoxy fill is vertically aligned and therefore co-planar with the planar outer surface of the polarizer). After planarizing in this way, the surface of the polarizer will be smooth and even, thereby facilitating the attachment of subsequent layers (e.g., the antireflection coating). 
     Approaches of the type shown in  FIG. 11  may be used in forming display structures of the type shown in  FIG. 6  or  FIG. 7  (as examples). For example, a structure of the type shown in  FIG. 5  may be formed before polarizer layer  102  is laminated onto the color filter by attaching thin film transistor layer  98  to the rear surface of the color filter, mounting driver circuits  118 , and forming planarized encapsulant structure  126  over circuits  118 . Structures of the type shown in  FIG. 7  without polarizer layer  102  may also be formed before polarizer layer  102  is laminated onto the color filter at step  176 . If desired, some of these fabrication steps (e.g., the attachment of chin film transistor layer  98  to color filter layer  100 ) may take place after the polarizer lamination and trimming operations of  FIG. 11  have been performed. 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.

Metadata:
Filing Date: 20140701
Publication Date: 20150630
Grant Date: 20150630
Priority Date: 20091110
Inventors: MATHEW DINESH C.
WILSON, JR. THOMAS W.
YIN VICTOR H.
POSNER BRYAN W.
LIGTENBERG CHRIS
DEGNER BRETT W.
AUGENBERGS PETERIS K.
ZHONG JOHN Z.
HOTELLING STEVE
YOUNGS LYNN
SUNG KUO-HUA
Assignee: APPLE INC
CPC Classifications: [{"code": "G02F2203/01", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T156/108", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01J2211/44", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01J9/205", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/13452", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133514", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133528", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1605", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/13452", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133512", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01J2211/44", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133514", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01J9/205", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y10T156/108", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133528", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133514", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/136218", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133388", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/13454", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133528", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 43973935