PATENT DOCUMENT

Publication Number: US-8944659-B2
Application Number: US-201213401692-A
Country: US
Kind Code: B2

Title: Methods for assembling electronic devices using embedded light guide structures

Abstract:
Electronic devices may include assemblies of structures such as electronic device assemblies connected using light-cured liquid adhesive such as ultraviolet-light-cured adhesive. Light guide structures may be mounted in the assemblies. During manufacture of an electronic device, ultraviolet light may be injected into a light guide structure to cure the light-cured liquid adhesive. A light guide structure may include portions that prevent escape of ultraviolet light and portions that allow ultraviolet light to escape into the light-cured liquid adhesive. Light guide structures may include masked portions, rigid support members, and one or more openings. Openings in a light guide structure may allow the light-cured liquid adhesive to be injected into an assembly through the openings. An adhesive applicator may be used to apply the adhesive to portions of the assembly. An external light source may be used to inject light that cures the adhesive into the light guide structures.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a housing; 
 a display layer; 
 an embedded light guide structure; and 
 ultraviolet-light-cured adhesive that attaches the housing to the display layer, wherein the embedded light guide structure is at least partially embedded in the ultraviolet-light-cured adhesive. 
 
     
     
       2. The electronic device defined in  claim 1 , further comprising a flexible light-emitting diode array attached to the display layer. 
     
     
       3. The electronic device defined in  claim 1  wherein the embedded light guide structure comprises a rigid support member and light guide material formed around the rigid support member. 
     
     
       4. The electronic device defined in  claim 3  wherein the rigid support member comprises a cylindrical rigid support member. 
     
     
       5. The electronic device defined in  claim 3  wherein the rigid support member comprises first and second portions and wherein the first portion is perpendicular to the second portion. 
     
     
       6. The electronic device defined in  claim 1  wherein the embedded light guide structure comprises first and second portions and wherein the first portion is formed from a first material having a first refractive index and the second portion is formed from a second material having a second refractive index that is different from the first refractive index. 
     
     
       7. The electronic device defined in  claim 1  wherein the embedded light guide structure comprises an external surface having first and second portions and wherein the first portion has a first surface roughness and the second portion has a second surface roughness that is greater than the first surface roughness. 
     
     
       8. The electronic device defined in  claim 1 , further comprising an internal lens, wherein the embedded light guide structure has an external surface that is partially covered by an opaque masking layer, wherein the internal lens is formed from an uncured portion of the ultraviolet-light-cured adhesive, and wherein the opaque masking layer is formed adjacent to the uncured portion of the ultraviolet-light-cured adhesive. 
     
     
       9. The electronic device defined in  claim 1  wherein the display layer and the housing are joined to form a corner, wherein the ultraviolet-light-cured adhesive is located in the corner, and wherein the embedded light guide structure has a bend in the corner. 
     
     
       10. An electronic device, comprising:
 a housing; 
 a display layer having first and second opposing edges; 
 ultraviolet-light-cured adhesive that attaches the housing to the display layer; and 
 first and second light guides adjacent to the ultraviolet-light cured adhesive, wherein the first light guide extends parallel to the first edge of the display layer and wherein the second light guide extends parallel to the second edge of the display layer. 
 
     
     
       11. The electronic device defined in  claim 10  wherein the first and second light guides are at least partially embedded in the ultraviolet-light-cured adhesive. 
     
     
       12. The electronic defined in  claim 10  wherein the first and second light guides each have an elongated shape with a curved surface. 
     
     
       13. The electronic device defined in  claim 10  wherein at least one of the first and second light guides has a bend. 
     
     
       14. The electronic device defined in clam  13  wherein the display layer and the housing form a corner and wherein the bend is located in the corner. 
     
     
       15. The electronic device defined in  claim 10  wherein at least one of the first and second light guides comprises a rigid support member and light guide material formed around the rigid support member. 
     
     
       16. The electronic device defined in  claim 15  wherein the rigid support member comprises a cylindrical rigid support member. 
     
     
       17. The electronic device defined in  claim 10  wherein the at least one of the first and second light guides comprises first and second portions and wherein the first portion is formed from a first material having a first refractive index and the second portion is formed from a second material having a second refractive index that is different from the first refractive index. 
     
     
       18. The electronic device defined in  claim 10  wherein at least one of the first and second light guides comprises an external surface having first and second portions and wherein the first portion has a first surface roughness and the second portion has a second surface roughness that is greater than the first surface roughness.

Description:
BACKGROUND 
     This relates generally to manufacturing techniques for electronic devices, and more particularly, to methods for forming assemblies using adhesive. 
     Adhesives are widely used in manufacturing. For example, electronic devices often include housings and structures that are attached to each other with pressure sensitive adhesive. In some situations it is difficult to use pressure sensitive adhesive to attach structures to each other. For example, if two parts must slide past each other during assembly, it may be necessary to attach the parts to each other using liquid adhesive rather than a layer of pressure sensitive adhesive. The liquid adhesive can flow during the assembly process and will not cause the two parts to bind to each other prematurely, whereas a layer of pressure sensitive adhesive might cause the two parts to become stuck before they have reached their proper positions. 
     A variety of liquid adhesives are available. Some glues cure chemically. For example, two-part epoxies and methyl methacrylate (MMA) adhesives cure upon mixing resin with hardener. Cyanoacrylate (CA) adhesive is activated by exposure to moisture. Other glues are cured by application of elevated temperatures. Curing mechanisms such as these often produce undesirable outgassing and can be difficult to control. 
     Satisfactory control and minimal outgassing can be achieved by using adhesives that are cured by application of ultraviolet (UV) light. For example, ultraviolet-light-cured (UV) epoxy can be used to attach metal and plastic parts in an electronic device. In a typical manufacturing process, uncured UV epoxy is applied to structures that are to be attached to each other. Once the structures are in their desired positions, UV light from a UV lamp is applied to the UV epoxy. This cures the UV epoxy. 
     In some product designs, it is awkward or impossible to expose the UV epoxy using a UV lamp. For example, if the UV epoxy is located in an interior portion of an assembly, walls or other parts of the assembly will block light from the UV lamp. 
     To allow UV epoxy to be used to assemble parts where the UV epoxy is located in the interior of the assembly, holes are formed in the parts. During manufacturing, a technician can insert a UV light wand into the interior portion of the assembly through the holes. The internal application of UV light using a UV wand requires the use of holes in the assembly that are large enough to accommodate the UV wand. The holes may be unsightly and may reduce the ability of the assembly to withstand environmental exposure to dust and moisture. 
     It would therefore be desirable to be able to provide improved techniques for assembling structures using light-sensitive adhesives. 
     SUMMARY 
     Electronic devices may include assemblies of structures that are formed using light-cured liquid adhesive such as ultraviolet-light-cured adhesive. Electronic device assemblies may include light guide structures that may guide light to internal portions of the electronic device for curing the light-cured adhesive. 
     The assemblies may include structures such as housing structures, displays, display layers, display cover layers, support structures, printed circuits, internal device members, subassemblies, and other structures. 
     The structures may be connected to each other to form an assembly within which the light guide structures are mounted. During assembly, ultraviolet-light-cured adhesive may be formed on one or more surfaces of one or more structures. Ultraviolet-light-cured adhesive may by formed around the light guide structures in the assembly or light guide structures may be inserted into ultraviolet-light-cured adhesive that has been formed on one or more structures. 
     A light guide structure may be implemented using optical fibers or other light guiding structures. A light guide structure may have one or more outer surfaces with portions that are configured to allow light to escape through the surface of the light guide structure and portions that are configured to prevent light from escaping through the surface of the light guide structure. 
     A light guide structure may include a removable portion for injecting light into the light guide structure while curing the ultraviolet-light-cured adhesive. Removable portions may be removed after curing the ultraviolet-light-cured adhesive. 
     A light guide structure may include one or more openings or cavities. Openings or cavities in light guide structures may allow ultraviolet-light-cured adhesive to be injected through a light guide structure mounted in an assembly into the assembly. Light such as ultraviolet light may be injected into light guiding portions of the light guide structure to cure the ultraviolet-light-cured adhesive that was injected through the openings in the light guide structure. 
     During assembly of an electronic device, an adhesive applicator may be used to inject ultraviolet-light-curable adhesive into an assembly. After injection of the ultraviolet-light-curable adhesive, an external light source may be coupled to a light guide in the assembly to inject light for curing the ultraviolet-light-curable adhesive into the light guide structure. After curing the ultraviolet-light-curable adhesive using the light source, the light source may be decoupled from the light guide structure and a portion of the light guide structure may remain at least partially embedded in the adhesive in the electronic device. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device with embedded light guide structures in accordance with an embodiment of the present invention. 
         FIG. 2  is a cross-sectional perspective view of an illustrative assembly having internal components that include a light guide structure for guiding light for curing adhesive in accordance with an embodiment of the present invention. 
         FIG. 3  is a perspective view of a portion of an illustrative light guide structure for guiding adhesive curing light having an exterior surface with portions that allow the light to escape in accordance with an embodiment of the present invention. 
         FIG. 4A  is a cross-sectional side view of an illustrative assembly of the type shown in  FIG. 2  showing how an adhesive delivery device may be used to form adhesive in the assembly in accordance with an embodiment of the present invention. 
         FIG. 4B  is a cross-sectional side view of a light source connected to an assembly showing how an external light source may inject light into a light guide structure within the assembly that cures adhesive within the assembly in accordance with an embodiment of the present invention. 
         FIG. 4C  is a cross-sectional side view of an illustrative assembly of the type shown in  FIG. 4A  showing how a light guide structure may remain in the assembly after curing of an adhesive in the assembly and after removal of a light source in accordance with an embodiment of the present invention. 
         FIG. 5  is a perspective view of a light guide structure having a non-circular profile in accordance with an embodiment of the present invention. 
         FIG. 6  is a cross-sectional side view of an illustrative assembly of the type shown in  FIG. 2  having a light guide structure with a non-circular profile in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of an illustrative assembly of the type shown in  FIG. 2  having a light guide structure with a non-circular profile and a portion for light injection that extends beyond an adhesive in accordance with an embodiment of the present invention. 
         FIG. 8  is a perspective view of a light guide structure having a temporary light injection structure in accordance with an embodiment of the present invention. 
         FIG. 9  is a perspective view of a light guide structure having an internal support structure in accordance with an embodiment of the present invention. 
         FIG. 10  is a perspective view of a light guide structure having an internal support structure and a non-circular profile in accordance with an embodiment of the present invention. 
         FIG. 11  is a perspective view of a light guide structure having openings for adhesive delivery in accordance with an embodiment of the present invention. 
         FIG. 12A  is a cross-sectional side view of an illustrative assembly of the type shown in  FIG. 2  showing how an adhesive delivery device may be used to inject adhesive into the assembly through a light guide structure in accordance with an embodiment of the present invention. 
         FIG. 12B  is a cross-sectional side view of a light source connected to an assembly showing how a light source may inject light into a light guide structure of the type shown in  FIG. 12A  to cure an adhesive within the assembly in accordance with an embodiment of the present invention. 
         FIG. 12C  is a cross-sectional side view of an illustrative assembly of the type shown in  FIG. 12A  showing how a light guide structure may remain in the assembly after curing of an adhesive in the assembly and after removal of a light source in accordance with an embodiment of the present invention. 
         FIG. 13  is a perspective view of a light guide structure having openings, and a non-circular profile for adhesive delivery in accordance with an embodiment of the present invention. 
         FIG. 14  is an exploded perspective view of an illustrative assembly that includes a light guide structure having a masked portion that prevents a pool of adhesive from being cured in accordance with an embodiment of the present invention. 
         FIG. 15  is a flow chart of illustrative steps involved in using adhesive that is cured using embedded light guide structures to assemble structures in accordance with an embodiment of the present invention. 
         FIG. 16  is a flow chart of illustrative steps involved in using adhesive that is cured using embedded light guide structures in accordance with an embodiment of the present invention. 
         FIG. 17  is a flow chart of illustrative steps involved in using adhesive that is cured using embedded light guide structures with openings to assemble structures in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Adhesive is widely used in connecting structures together. For example, electronic devices such as computers, cellular telephones, media players, and other electronic equipment often contains parts that are connected to each other using layers of liquid adhesive. Liquid adhesive allows parts to be moved relative to each other as part of the assembly process. For example, parts may slide with respect to each other before the adhesive has been applied or after the adhesive has been applied and before the adhesive has cured. Once the adhesive has cured, the parts become secured to one another and can be used in a finished product. 
     Adhesives can be activated chemically, thermally, or using light. For example, chemically activated two-part adhesives are available that have a hardener and a resin. When the hardener is mixed with the resin, a chemical reaction is created that cures the adhesive. Thermal curing typically involves raising an adhesive above room temperature. This type of curing process often produces undesirable outgassing and can be difficult to control. 
     As a result, adhesives are sometimes used that are cured by application of light. In a typical arrangement, ultraviolet (UV) light is applied to a UV-cured adhesive such as UV epoxy. It can be difficult or impossible to use this approach when the UV epoxy is located on the inside of an assembly. UV light wands can sometimes be inserted through holes in an assembly to reach the interior of the assembly. This allows UV light to be applied to UV adhesive within the assembly, but requires that holes be formed. The presence of the holes in parts of a device can adversely affect device aesthetics and structural integrity. 
     To overcome these shortcomings of conventional adhesive curing techniques, an assembly may be provided with an embedded light guide structure. Liquid adhesive may be applied to the structures that make up the assembly. Liquid adhesive may be formed between structures that make up the assembly and partially or wholly surrounding the embedded light guide structure. When the liquid adhesive and the structures that make up the assembly are in proper position, a light source may be coupled to a portion of the embedded light guide structure to inject light into the light guide structure. 
     The embedded light guide structure may have portions that allow the light to escape so that the light guide structure guides the light into predetermined regions of the assembly. Light that escapes from the embedded light guide structure into the adhesive can cure the adhesive from within the assembly. This may reduce or eliminate the need to from holes in the assembly to accommodate an external light source such as a UV wand. Once the adhesive has been cured, the light source can be decoupled from the embedded light guide structure. 
     If desired, the light guide structure may include a temporary extended removable portion for coupling to the light source. If desired, the light guide structure may include openings that allow the adhesive to be injected into the assembly through the embedded light guide structure. 
     An illustrative electronic device of the type that may be provided with one or more embedded light guide structures is shown in  FIG. 1 . Electronic device  10  may be a portable electronic device or other suitable electronic device. For example, electronic device  10  may be a laptop computer, a tablet computer, a somewhat smaller device such as a wrist-watch device, pendant device, headphone device, earpiece device, or other wearable or miniature device, a cellular telephone, a media player, a gaming device, etc. 
     Device  10  may include a housing such as housing  12 . Housing  12 , which may sometimes be referred to as a case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of these materials. In some situations, parts of housing  12  may be formed from dielectric or other low-conductivity material. In other situations, housing  12  or at least some of the structures that make up housing  12  may be formed from metal elements. 
     Device  10  may, if desired, have a display such as display  14 . Display  14  may, for example, be a touch screen that incorporates capacitive touch electrodes. Display  14  may include image pixels formed from light-emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells, electronic ink elements, liquid crystal display (LCD) components, or other suitable image pixel structures. A cover glass layer may cover the surface of display  14 . Portions of display  14  such as peripheral regions  201  may be inactive and may be devoid of image pixel structures. Portions of display  14  such as rectangular central portion  20 A (bounded by dashed line  20 ) may correspond to the active part of display  14 . In active display region  20 A, an array of image pixels (e.g., a flexible or rigid light-emitting-diode array) may be used to display images for a user. 
     The cover glass layer that covers display  14  may have openings such as a circular opening for button  16  and a speaker port opening such as speaker port opening  18  (e.g., for an ear speaker for a user). Device  10  may also have other openings (e.g., openings in display  14  and/or housing  12  for accommodating volume buttons, ringer buttons, sleep buttons, and other buttons, openings for an audio jack, data port connectors, removable media slots, etc.). 
     Device  10  may include one or more embedded light guide structures such as light guide structures  30  (sometimes referred to herein as light pipes, fiber-optic light guides, or light guides). Light guides  30  may be located internal to device  10  along the edges of device  10 , near the rear or front of device  10 , as extending elements or attachable structures, or elsewhere in device  10 . With one suitable arrangement, which is sometimes described herein as an example, device  10  may be provided with one or more light guide structures  30  along a first side such as left end  23  of housing  12  and one or more light guide structures  30  along an opposing second side such as right end  25  of housing  12 . 
     As shown in  FIG. 1 , embedded light guide structures  30  may be formed along a single edge of device  10  or may have portions along multiple edges (e.g., perpendicular edges) of device  10 . If desired, light guide structures  30  may be located in lower region  24  and upper region  22 . During assembly of device  10 , light guide structures  30  may be coupled to one or more components of an assembly system (e.g., adhesive delivery devices, light sources, etc.). Light may be injected into an edge or other surface of a light guide structure such as light guide structures  30  to cure liquid adhesive for forming interior assemblies of device structures such as housing structures, displays, printed circuits, batteries, support frames, and display cover layers. 
     The use of device housing structures and embedded light guide structures of the type shown in  FIG. 1  is merely illustrative. Electronic device  10  may have the shape of a tablet computer, may be implemented using device housings with other portable shapes, or may be implemented as part of other suitable electronic equipment. Two or more light guide structures, three or more light guide structures, four or more light guide structures, or other suitable number of light guide structures may be used in device  10 . 
     An illustrative assembly of the type that may be provided with an embedded light guide structure for curing liquid adhesive is shown in  FIG. 2 . As shown in the perspective view of illustrative device  10  of  FIG. 2 , device  10  may contain an assembly of multiple structures such as housing structure  12 , display  14 , display layer  14 C (e.g., a display cover glass), support structures  34  and light guides such as embedded light guide structures  30  that are secured together using a light-cured-adhesive such as ultraviolet-light-cured adhesive  32 . Adhesive  32  may be a light-cured adhesive such as ultraviolet (UV) epoxy or other UV adhesive (sometimes referred to as ultraviolet-light-cured liquid adhesive, ultraviolet-light liquid adhesive, light-cured liquid adhesive, light-curable liquid adhesive, or ultraviolet liquid adhesive). UV epoxy and other UV adhesives are liquid until exposed to UV light. 
     In the example of  FIG. 2 , structures  12  and display layer  14 C are structures that, when assembled, form an enclosure that surrounds internal components such as display  14 . Structures  12  may, for example, be housing structures or other structures that have sidewalls. When structures such as structures  12  and display layer  14 C are attached to each other, the structures  12  and display layer  14 C may form a substantially enclosed internal cavity. Light guides  30  may be located within the internal cavity and may remain within the internal cavity after the adhesive has been cured. The shapes and sizes of structures  12  are merely illustrative. In general, the structures from which assembly  10  is formed may have any suitable configuration. 
     In general, any suitable number of structures may be assembled together using adhesive (e.g., two structures, more than two structures, three structures, more than three structures, four structures, more than four structures, etc.). The structures can be attached together to form a completed device (e.g., a product that is sold to an end user) or may be used to form a part of a device (e.g., a structure to which additional components are added before the structure is complete and ready to be sold to a user). Structures that are attached together with adhesive are sometimes referred to herein as parts, members, structures, pieces, components, housings, etc. The resulting assemblage of parts may sometimes be referred to as an assembly, a device, a product, an electronic device (e.g., a completed assembly), a structure, etc. 
     The structures from which assembly  10  is formed may include one or more embedded light guides such as light guides  30 . During manufacturing, adhesive  32  may be applied to the structures of assembly  10 . Adhesive  32  may be applied to the structures of an assembly such as assembly  10  having light guide structures  30  or light guide structures  30  may be inserted into adhesive  32  after adhesive  32  has been applied to the structures of assembly  10 . An external light source may be coupled to light guide structures  30  in order to inject light into device  10  to cure the adhesive. After curing, light guides  30  may remain as part of the assembly. 
     Light guide structures  30  may include features such as openings, cavities, surface roughness, masking layers or other features that help in applying and curing adhesive within assembly  10 . Light guide structures  30  may include surface features on one or more external surfaces of light guide structures  30  that help guide light to desired portions of assembly  10  while keeping light that may be harmful to light sensitive device components away from other portion of assembly  10 . As an example, light guides structures  30  may include portions that allow light to escape and portions that prevent light from escaping as shown in  FIG. 3 . 
     As shown in  FIG. 3 , light guide  30  may have a substantially elongated shape with an outer surface such as surface  37  and edges such as edges  36 . Light guide  30  may be formed from an optical fiber that allows light to enter and exit light guide  30  from edges  36  and (based on the principle of total internal reflection) prevents light from escaping through other surfaces of light guide  30 . For example, light such as incident light  42 I may be injected into light guide  30  though an edge such as edge  36  using a light source such as light source  40 . 
     Light  42 I may be guided within parts of light guide  30  and a portion of light  42 I such as light  42 E may exit light guide  30  from an opposing end  36 . Light  42 I may include ultraviolet light, visible light, infrared light or other frequency of light. Exiting light  42 E may exit light guide  30  in the vicinity of adhesive such as adhesive  32  of  FIG. 2 . In this way, light guide  30  may serve as a light pipe that helps to guide and distribute light  42 I from light source  40  to adhesive  32 . Upon reaching adhesive  32 , light  42 E may be absorbed and distributed within adhesive  32  to cure adhesive  32 . 
     Transparent light pipe structures such as light guide  30  may be formed from transparent plastic, glass, transparent ceramics, etc. As shown in  FIG. 3 , surface  37  of light guide  30  may include surface features such as opaque masking layer  42  or portions such as portions  38  that allow light  42 C to escape from portions  38  of surface  37 . Portion  38  may be formed from a material that is different from other portions such as portion  46  of light guide  30 . Portions  46  and portions  38  may be formed from materials having different refractive indices. Portion  46  may be formed from a fiber optic material that prevents light from escaping through surface  37 . However, this is merely illustrative. 
     If desired, portion  38  and portion  46  may be formed from a common material. In configurations in which portions  38  and portions  46  are formed from the same material, surface  37  may have a surface roughness in portions  38  that is different from the surface roughness of surface  37  in portions  46 . Surface roughness on surface  37  of portion  38  may help match a refractive index of surface  37  in portion  38  with a refractive index of adhesive  32 . Providing light guide  30  with portions  38  having a refractive index that is matched to the refractive index of adhesive  32  may allow light  42 C to escape from light guide  30  through surface  37  into adhesive  32 . Upon reaching adhesive  32 , light  42 C may be absorbed and distributed within adhesive  32  to cure adhesive  32 . 
     Opaque masking layers such as layer  44  may be formed in fiber optic portions such as portion  46  or in light escape portions such as portion  38  of light guide  30 . Opaque masking layer  44  may be formed from black ink, silver ink, black plastic, aluminum, or other opaque masking material. Opaque masking layer  44  may help prevent light from escaping from portions of light guide  30  in the vicinity of light sensitive components of device  10 . 
     Light guide  30  may be formed as an integral member of an assembly during manufacturing of device  10  as shown in  FIGS. 4A ,  4 B, and  4 C. As shown in  FIG. 4A , a mechanical housing such as housing  50  may be used to hold structures such as components  52  and  54  during manufacturing of assembly  10 . Housing  50  may be a portion of housing  12  of a device  10  (see  FIG. 1 ) or may be a temporary mechanical housing that is used during assembly of device  10 . Components  52  and  54  may include a display such as display  14 , a display cover glass such as display layer  14 C, an internal frame such as frame  34 , a battery or other component associated with device  10  (see, e.g.,  FIG. 2 ). 
     As shown in  FIG. 4A , adhesive  32  may be applied to components  52 ,  54  and light guide  30  using an adhesive delivery device such as adhesive applicator  56 . Adhesive applicator  56  may include a reservoir such as reservoir  58  of adhesive  32 . Applicator  56  may be connected to a robotic positioning table such as positioning mechanism  60  for automatically moving applicator  56  into position for applying adhesive  32  to assembly  10 . Positioning mechanism  60  may be controlled by computing equipment such as control computer  62 . Control computer  62  may include processing circuitry configured to drive motors associated with positioning mechanism  60  for applying adhesive  32  with applicator  56 . 
     Adhesive  32  may be injected into a space between components such as components  52  and  54  surrounding a light guide such as light guide  30 . However, this is merely illustrative. If desired, adhesive  32  may be applied in a space between components  52  and  54  followed by insertion of light guide  30  into adhesive  32  (as indicated by arrow  65 ). Light guide  30  may be provided with a temporary extended portion for injection of light such as removable portion  64 . Removable portion  64  may extend from mechanical housing  50  to allow attachment of a light delivery source such as light source  66  as shown in  FIG. 4B . 
     In the example of  FIG. 4B , light source  66  may be coupled to light guide  30  using removable portion  64 . This is merely illustrative. If desired, light source  66  may be coupled directly to permanent portions of light guide  30 . Light source  66  may be based on one or more light-emitting diodes (LEDs), one or more lamps, etc. For example, the light source may include one or more UV LEDs. 
     As shown in  FIG. 4B , light source  66  may be configured to generate (e.g., ultraviolet) light  42 I to be injected into a light guide such as light guide  30  that is at least partially embedded in a light curable adhesive such as adhesive  32 . Light guide  30  may be configured to guide light  42 I into adhesive  32 . Portions of light  42 I such as light  42 E may exit light guide  30  from an end such as end  36 . Portions of light  42 I may escape through light escape portions such as portion  38  of surface  37  of light guide  30 . Upon reaching adhesive  32 , light  42 E and light  42 C may be absorbed and distributed within adhesive  32  to cure adhesive  32 . 
     Following curing of adhesive  32 , light source  66  may be removed from light guide  30 . In configurations in which light guide  30  is provided with a removable portion  64 , removable portion  64  may be removed following curing of adhesive  32  with light from light source  66 . As shown in  FIG. 4C , assembly  10  may be provided with an embedded internal light guide structure such as light guide  30  embedded in cured adhesive  32 . Mechanical housing  50  may remain coupled to components such as component  52  and form a portion of a device housing such as housing  12  (see  FIG. 1 ) or an assembly  10  including components  52  and  54  and light guide  30  may be removed from mechanical housing structure  50  an inserted into a device housing such as housing  12 . 
     The configurations of  FIGS. 2 ,  3 ,  4 A,  4 B, and  4 C in which light guide  30  has a substantially cylindrical shape are merely illustrative. Light guide structure  30  may have an elongated shape with substantially planar exterior surfaces, or may have other shapes. As shown in  FIG. 5 , light guide  30  may have an edge  36  having an L-shaped profile and an exterior surface  37  having one or more planar surfaces  37 P. Planar surfaces  37 P may include portions such as portion  70  for injecting incident light  42 I and portions  38  from which light  42 C may escape from light guide  30  into adhesive such as adhesive  32 . Incident light  42 I may be injected into edge  36 , into portion  70  of planar surface  37 P, or into both edge  36  and portion  70 . 
     As shown in  FIG. 6 , light  42 C may escape from one or more planar surfaces  37 P of light guide  30  into adhesive  32 . Providing light guide  30  with an L-shaped edge profile as in the example of  FIG. 6  may allow light guide  30  to conform to corners or corner joints such as the junction of a device housing  12  and a display cover glass layer such as layer  14 C. After curing of adhesive  32 , light guide  30  having an L-shaped edge profile may be fully embedded in adhesive  32 . However, this is merely illustrative. 
     If desired, a portion such as portion  70  may extend beyond adhesive  32  as shown in  FIG. 7 . Portion  70  may extend beyond adhesive  32  so that light  42 I may be injected into light guide  30  though a planar surface such as planar surface  37 P. 
     As shown in  FIG. 8 , a light guide having an L-shaped edge profile may be provided with a temporary extended portion such as removable portion  64  having an edge  36  with an L-shaped profile. Removable portion  64  may allow attachment of a light delivery source such as light source  66  as shown in  FIG. 4B . Removable portion  64  may have planar surfaces  37 P such as portion  70  for injection of incident light  42 I. Incident light  42 I may be injected into edge  36  or portion  70  of removable portion  64  and guided in to light guide  30 . Light guide  30  may guide portions of incident light  42 I and portions of light  42 I may escape from planar surfaces  37 P of light guide  30  in portions  38  of light guide  30 . 
       FIG. 9  shows a perspective view of a portion of a light guide  30  having a rigid support member such a support member  72 . Rigid support member  72  may be a cylindrical support member that runs along an extended dimension of light guide  30  parallel to the y-axis of  FIG. 9  or may have other shapes. Rigid support member  72  may be formed from plastic, metal, composites, ceramics, or other suitable rigid materials. 
     Light guide  30  may include a rigid support member such as support member  72  and a light guiding structure formed from light guide material formed around support member  72 . Light guide material  74  may be formed from glass, plastic or other transparent or fiber optic material capable of guiding incident light such as light  42 I that is incident on an edge  36  of structure  74  into interior portions of an assembly. Structure  74  of light guide  30  may include an outer surface  37  having portions  46  that prevent light from escaping (e.g., due to total internal reflection of light) and portions  38  (e.g., portions with relatively greater surface roughness) that allow light such as light  42 C to escape from light guide  30  into adhesive such as adhesive  32 . 
     As shown in  FIG. 10 , an internal rigid support member such as member  72  may have a first portion  72 - 1  that is substantially perpendicular to a second portion  72 - 2 . An embedded light guide such as light guide  30  having an internal rigid support member  72  with perpendicular portions  71 - 1  and  72 - 1  may have a light guide structure such as structure  74  formed around rigid support member  72 . 
     Structure  74  may be formed from glass, plastic or other transparent material capable of guiding incident light such as light  42 I that is incident on an edge  36  or planar surface  37 P of structure  74  into interior portions of an assembly. Structure  74  of light guide  30  may include an outer surface  37 . Surface  37  may include planar outer surfaces  37 P. Surfaces  37 P may include portions  46  that prevent light from escaping (e.g., due to total internal reflection of light) and portions  38  (e.g., portions with relatively greater surface roughness) that allow light such as light  42 C to escape from light guide  30  into adhesive such as adhesive  32 . 
     As shown in  FIG. 11 , light guide  30  may include one or more openings such as openings  80  and opening  84 . Opening  84  may include an opening in edge  36  of light guide  30  that runs along the length of light guide  30 . Adhesive  32  may be injected into opening  84  of light guide  30  as indicated by arrow  82  during manufacturing of device  10 . Openings  80  in surface  37  of light guide  30  may extend into contact with opening  84 . Openings  80  may be configured to allow liquid adhesive  32  that is injected into opening  84  of light guide  30  to flow through openings  80  and into portions of an assembly such as assembly  10 . In this way, adhesive may be formed around light guide  30  and among components of an assembly by injecting adhesive into opening  80  of a light guide  30  that forms a portion of the assembly as shown in  FIGS. 12A ,  12 B, and  12 C. 
     As shown in  FIG. 12A , during manufacturing of device  10 , a mechanical housing such as housing  50  may be used to hold structures such as components  52  and  54  during manufacture of assembly  10 . Housing  50  may be a portion of housing  12  of a device  10  (see  FIG. 1 ) or may be a temporary mechanical housing that is used during assembly of device  10 . Components  52  and  54  may include a display such as display  14 , a display cover glass such as display layer  14 C, an internal frame such as frame  34 , a battery or other component associated with device  10  (see, e.g.,  FIG. 2 ). 
     As shown in  FIG. 12A , adhesive  32  may be applied to components  52 ,  54  and light guide  30  using an adhesive delivery device such as adhesive applicator  56 . Adhesive applicator  56  may include a reservoir such as reservoir  58  of adhesive  32 . Applicator  56  may be connected to a robotic positioning table such as positioning mechanism  60  for automatically moving applicator  56  into position for applying adhesive  32  to assembly  10 . Positioning mechanism  60  may be controlled by computing equipment such as control computer  62 . Control computer  62  may include processing circuitry configured to drive motors associated with positioning mechanism  60  for applying adhesive  32  with applicator  56 . 
     Adhesive  32  may be injected into an opening such as opening  84  in light guide  30 . Adhesive  32  may flow (as indicated by arrows  90 ) into assembly  10  through openings  80  in light guide  30 . Adhesive  32  may flow from openings  80  and substantially fill a space between components such as components  52  and  54  an at least partially surrounding a light guide such as light guide  30 . Light guide  30  may be provided with a temporary section such as removable portion  64  having an extension of opening  84  though which adhesive  32  may be injected. Removable portion  64  may extend from mechanical housing  50  to allow attachment of a light delivery source such as light source  66  as shown in  FIG. 12B . 
     In the example of  FIG. 12B , light source  66  may be coupled to light guide  30  using removable portion  64 . This is merely illustrative. If desired, light source  66  may be coupled directly to permanent portions of light guide  30 . 
     As shown in  FIG. 12B , following injection of adhesive  32  into assembly  10  through openings  84  and  80 , light source  66  may be configured to generate (e.g., ultraviolet) light  42 I and inject light  42 I into light guide  30 . Light guide  30  may be configured to guide light  42 I into adhesive  32 . Portions of light  42 I such as light  42 E may exit light guide  30  from an end such as end  36 . Portions of light  42 I such as light  42 C may escape through light escape portions such as portion  38  of surface  37  of light guide  30 . Upon reaching adhesive  32 , light  42 E and light  42 C may be absorbed and distributed within adhesive  32  to cure adhesive  32 . 
     Following curing of adhesive  32 , light source  66  may be removed from light guide  30 . In configurations in which light guide  30  is provided with a removable portion  64 , removable portion  64  may be removed following curing of adhesive  32  with light from light source  66 . As shown in  FIG. 12C , assembly  10  may be provided with an embedded internal light guide structure such as light guide  30  embedded in cured adhesive  32 . Cured adhesive  32  may substantially fill opening  84  and openings  80  in light guide  30 . 
     Mechanical housing  50  may remain coupled to components such as component  52  to form a portion of a device housing such as housing  12 , a frame such as frame  34  (see  FIG. 2 ) or an assembly  10  including components  52  and  54  and light guide  30  may be removed from mechanical housing structure  50  an inserted into a device housing such as housing  12 . 
     The configurations of  FIGS. 11 ,  12 A,  12 B, and  12 C in which light guide  30  has an opening  84  having a substantially cylindrical shape that runs along an extended dimension of light guide  30  (e.g., parallel to the y-axis of  FIG. 11 ) are merely illustrative. Light guide structure  30  may have an opening  84  in edge  36  having any shape and extending into light guide  30 . 
     As shown in  FIG. 13 , light guide  30  may have an edge  36  having an L-shaped profile and an exterior surface  37  having one or more planar surfaces  37 P and one or more openings such as opening  84  an opening  80 . In configurations in which edge  36  has an L-shaped profile, opening  80  may include first and second portions  84 - 1  and  84 - 2  that are substantially perpendicular. Planar surfaces  37 P may include portions such as portion  70  for injecting incident light  42 I and portions  38  from which light  42 C may escape from light guide  30  into adhesive such as adhesive  32 . Incident light  42 I may be injected into edge  36 , into portion  70  of planar surface  37 P, or into both edge  36  and portion  70 . Light guide  30  may include portions  46  that prevent light  42  from escaping. 
     Light guide  30  may include one or more openings such as openings  80  and opening  84 . Opening  84  may include an opening in edge  36  of light guide  30  that runs along the length of light guide  30 . Adhesive  32  may be injected into opening  84  of light guide  30  as indicated by arrow  82  during manufacturing of device  10 . Openings  80  in outer surface  37  of light guide  30  may extend into contact with opening  84 . Openings  80  may be configured to allow liquid adhesive  32  that is injected into opening  84  of light guide  30  to flow through openings  80  and into portions of an assembly such as assembly  10 . In this way, adhesive may be formed around light guide  30  and among components of an assembly by injecting adhesive into opening  80  of a light guide  30  that forms a portion of the assembly. 
     Following injection of adhesive  32  through openings  84  and  80 , light  42 I that is injected into edge  36  and/or portion  70  may escape from one or more planar surfaces  37 P of light guide  30  into adhesive  32 . Providing light guide  30  with an L-shaped edge profile as in the example of  FIG. 13  may allow light guide  30  to conform to corners or corner joints such as the junction of a device housing  12  and a display cover glass layer such as layer  14 C. After curing of adhesive  32 , light guide  30  having an L-shaped edge profile and openings  84  and  80  may be at least partially embedded in adhesive  32 . 
     Portions of light guide  30  may be provided with an opaque masking layer such as layer  44  configured to prevent portions such as portions  42 C of light  42 I from reaching portions of a light-curable material such as light-curable material  100  (e.g., a transparent light-curable resin or polymer, an opaque light-curable adhesive, etc.) as shown in  FIG. 14 . Masked portions  44  of light guide  30  may help leave one or more portions such as portion  100 U uncured. 
     Light-curable material  100  may be interposed between a light guide such as light guide  30  and a cover layer such as cover layer  102 . Cover layer  102  may be transparent or opaque. Cover layer  102  may be an interior or exterior member of device  10 . Cover layer  102  may be formed from plastic, glass, ceramics, composites or other suitable materials. Uncured portions such as portion  100 U of light-curable material  100  may have a refractive index that is different from cured portions of light-curable material  100 . Uncured portions  100 U may therefore be configured to form an internal lens for redirecting light within an assembly. For example, external light may pass through cover layer  102  and be redirected within device  10 , internal light (e.g., light generated by display pixels of a display such as display  14  of  FIG. 1 ) may be redirected outward of device  10  or within device  10  by uncured portion  100 U. 
       FIG. 15  shows illustrative steps that may be involved in forming assemblies (e.g., electronic devices, portions of electronic devices, or other groups of structures) by connecting structures with liquid adhesive and applying light to the adhesive from a light guide structure in the assembly. The light guide structure may, for example, be inserted at least partially into the adhesive after application of the adhesive to structures in the assembly. 
     At step  110 , light-curable liquid adhesive (e.g., ultraviolet-curable adhesive) may be applied to one or more structures such as device components (e.g., printed circuit boards, housing structures and other structures for the assembly). 
     At step  112 , a light guide structure (light guide) may be inserted into the ultraviolet-curable adhesive. 
     At step  114 , ultraviolet light may be injected into the light guide structure. Portions of the injected ultraviolet light may escape from portions of the light guide into the ultraviolet-curable adhesive. The portions of the ultraviolet light that escape from the light guide may cure the ultraviolet-curable adhesive. 
     An ultraviolet light source may be coupled to the light guide structure for injection of the ultraviolet light into the light guide. 
     At step  116 , a temporary extension to the light guide for light injection may optionally be removed from the light guide. However, this is merely illustrative. The light source may inject light directly into the light guide without a temporary extension for light injection. 
       FIG. 16  shows illustrative steps that may be involved in forming assemblies (e.g., electronic devices, portions of electronic devices, or other groups of structures) by connecting structures with liquid adhesive and applying light to the adhesive from a light guide structure that is pre-positioned in the assembly. 
     At step  111 , structures (e.g., a printed circuit board, a housing structure, a display cover layer, an interior frame, and other structures for the assembly) that include a light guide structure (light guide) may be assembled for an assembly. For example, the structures may be assembled in a temporary or permanent mechanical housing for assembly during manufacturing of a device. 
     At step  113 , light-curable liquid adhesive (e.g., ultraviolet-curable adhesive) may be applied to portions of one or more structures of the assembly at least partially surrounding the light guide. 
     At step  115 , ultraviolet light may be injected into the light guide structure. Portions of the injected ultraviolet light may escape from portions of the light guide into the ultraviolet-curable adhesive. The portions of the ultraviolet light that escape from the light guide may cure the ultraviolet-curable adhesive. 
     An ultraviolet light source may be coupled to the light guide structure for injection of the ultraviolet light into the light guide. 
     At step  117 , a temporary extension to the light guide for light injection may optionally be removed from the light guide. However, this is merely illustrative. The light source may inject light directly into the light guide without a temporary extension for light injection. 
       FIG. 17  shows illustrative steps that may be involved in forming assemblies (e.g., electronic devices, portions of electronic devices, or other groups of structures) by connecting structures with liquid adhesive injected into the assemblies using openings in a light guide structure that is pre-positioned in the assembly. 
     At step  120 , structures (e.g., a printed circuit board, a housing structure, a display cover layer, an interior frame, and other structures for the assembly) that include a light guide structure (light guide) having openings for injections of liquid light-curable adhesive may be assembled for an assembly. For example, the structures may be assembled in a temporary or permanent mechanical housing for assembly during manufacturing of a device. 
     At step  122 , light-curable liquid adhesive (e.g., ultraviolet-curable adhesive) may be applied to portions of one or more structures of the assembly by injecting the ultraviolet-curable adhesive into an opening in the light guide. The light guide may be provided with additional openings that allow the ultraviolet-curable adhesive to flow from the light guide into the assembly at least partially surrounding the light guide. 
     At step  124 , ultraviolet light may be injected into the light guide structure. Portions of the injected ultraviolet light may escape from portions of the light guide into the ultraviolet-curable adhesive. The portions of the ultraviolet light that escape from the light guide may cure the ultraviolet-curable adhesive. 
     An ultraviolet light source may be coupled to the light guide structure for injection of the ultraviolet light into the light guide. 
     At step  126 , a temporary extension to the light guide for light and adhesive injection may optionally be removed from the light guide. However, this is merely illustrative. The light and light-curable liquid adhesive may be injected directly into the light guide structure without a temporary extension. 
     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. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20120221
Publication Date: 20150203
Grant Date: 20150203
Priority Date: 20120221
Inventors: DABOV TEODOR
FEINSTEIN CASEY J.
PAKULA DAVID A.
LYNCH STEPHEN BRIAN
Assignee: APPLE INC
CPC Classifications: [{"code": "G02B6/0081", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B6/0086", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/001", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B6/102", "inventive": true, "first": false, "tree": "[]"}, {"code": "C09J5/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/102", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/001", "inventive": true, "first": false, "tree": "[]"}, {"code": "C09J2203/318", "inventive": false, "first": false, "tree": "[]"}, {"code": "C09J2301/416", "inventive": false, "first": false, "tree": "[]"}, {"code": "C09J2203/318", "inventive": false, "first": false, "tree": "[]"}, {"code": "C09J5/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/0086", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/0081", "inventive": true, "first": true, "tree": "[]"}, {"code": "C09J2301/416", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 48956714