PATENT DOCUMENT

Publication Number: US-12157289-B2
Application Number: US-202318457522-A
Country: US
Kind Code: B2

Title: Seals for optical components

Abstract:
An electronic device may have optical components that each have first and second transparent layers such as first and second glass layers. The glass layers may have outer surfaces that face away from each other and inner surfaces that face towards each other. A polymer layer is formed between the inner surfaces of the glass layers. Along the periphery of each optical component, a hermetic seal is formed to protect the polymer material of the polymer layer. The seal may include one or more metal layers that are coupled to the first and second glass layers. For example, glass prism rings may be coupled to the first and second glass layers and metal may be coupled to the prism rings. The one or more metal layers may then be bonded to the metal on the prism rings, such as through soldering.

Claims:
What is claimed is: 
     
       1. An optical component, comprising:
 first and second transparent layers; 
 a polymer layer between the first and second transparent layers, wherein the polymer layer has a peripheral edge; 
 first and second metal layers respectively adjacent to the first and second transparent layers; and 
 a seal formed from a barrier layer that hermetically seals the peripheral edge, wherein the barrier layer is coupled to the first and second metal layers. 
 
     
     
       2. The optical component of  claim 1 , wherein the barrier layer comprises first and second L-shaped metal layers. 
     
     
       3. The optical component of  claim 2 , wherein the first and second L-shaped metal layers comprise plated aluminum. 
     
     
       4. The optical component of  claim 2 , wherein the first and second L-shaped metal layers have overlapping portions that overlap the peripheral edge, and wherein the overlapping portions are soldered. 
     
     
       5. The optical component of  claim 1 , wherein the first and second transparent layers are glass, the optical component further comprising:
 first and second glass prism rings respectively coupled to the first and second transparent layers. 
 
     
     
       6. The optical component of  claim 5 , wherein the first and second glass prism rings comprise first surfaces that are welded to the first and second transparent layers, the first and second glass prism rings comprise second surfaces, and the first and second metal layers are respectively formed on the second surfaces of the first and second glass prism rings. 
     
     
       7. The optical component of  claim 6 , wherein the barrier layer is soldered to the first and second metal layers. 
     
     
       8. The optical component of  claim 6 , further comprising:
 first and second portions of desiccant material respectively interposed between the first and second glass prism rings and the barrier layer. 
 
     
     
       9. The optical component of  claim 1 , further comprising:
 a buffer layer interposed between the peripheral edge and the barrier layer. 
 
     
     
       10. The optical component of  claim 9 , wherein the buffer layer comprises a metal foil layer, and wherein the metal foil layer is plated with nickel and gold. 
     
     
       11. The optical component of  claim 1 , further comprising:
 a first layer of dark deposition material interposed between the first transparent layer and the first metal layer; and 
 a second layer of dark deposition material interposed between the second transparent layer and the second metal layer. 
 
     
     
       12. The optical component of  claim 11 , wherein the first and second layers of dark deposition material comprise a material selected from the group consisting of: amorphous silicon, chromium, CrC, Tungsten, WC, and nickel. 
     
     
       13. The optical component of  claim 11 , wherein the first and second metal layers each comprises a first metal layer, a second metal layer, and a third metal layer, wherein the first metal layer is in contact with the first layer of dark deposition material or the second layer of the dark deposition material, the optical component further comprising:
 solder between the barrier layer and the third metal layers. 
 
     
     
       14. The optical component of  claim 13 , wherein the first metal layer comprises titanium or chromium, the second metal layer comprises nickel or copper, and the third metal layer comprises silver or gold. 
     
     
       15. An optical component, comprising:
 a first glass layer comprising first and second opposing surfaces; 
 a second glass layer comprising third and fourth opposing surfaces; 
 a polymer layer coupled to the second and third surfaces; 
 a first glass prism ring coupled to the first surface; 
 a second glass prism ring coupled to the fourth surface; and 
 a seal formed along a peripheral edge of the polymer layer, wherein the seal includes a barrier layer that is coupled to the first glass prism ring and to the second glass prism ring. 
 
     
     
       16. The optical component of  claim 15 , further comprising:
 first and second metal layers respectively formed on the first and second glass prism rings, wherein the barrier layer is soldered to the first and second metal layers. 
 
     
     
       17. The optical component of  claim 16 , wherein the barrier layer comprises first and second L-shaped metal layers, the first L-shaped metal layer is soldered to the first metal layer, the second L-shaped metal layer is soldered to the second metal layer, and the first and second L-shaped metal layers are soldered together. 
     
     
       18. The optical component of  claim 17 , wherein the first and second glass prism rings are welded to the first and fourth surfaces. 
     
     
       19. The optical component of  claim 18 , wherein the first and second glass prism rings are triangular prism rings having first, second, and third sides, wherein the first and second metal layers are sputtered onto the first sides of the first and second glass prism rings, and wherein the second sides are welded to the first and fourth surfaces. 
     
     
       20. The optical component of  claim 19 , wherein the third sides of the first and second glass prism rings form laser-welding windows. 
     
     
       21. The optical component of  claim 17 , wherein the first and second L-shaped metal layers comprise nickel-and-gold-plated metal foils. 
     
     
       22. The optical component of  claim 17 , wherein the first and second L-shaped metal layers have thicknesses of less than 30 microns. 
     
     
       23. An electronic device, comprising:
 a support structure; 
 an optical component supported by the support structure, wherein the optical component has first and second glass layers, and has a polymer layer between the first and second glass layers; and 
 a hermetic seal formed along a peripheral edge of the optical component, wherein the hermetic seal comprises:
 first and second glass prism layers respectively formed on the first and second glass layers; 
 third and fourth metal layers respectively formed on the first and second glass prism layers; 
 a first metal layer soldered to the third metal layer; and 
 a second metal layer soldered to the fourth metal layer. 
 
 
     
     
       24. The electronic device of  claim 23 , wherein the first and second metal layers are soldered together, and wherein the first and second glass prism layers are respectively welded to the first and second glass layers. 
     
     
       25. An optical component, comprising:
 first and second transparent layers; 
 a polymer layer between the first and second transparent layers, wherein the polymer layer has a peripheral edge; 
 desiccant tape adjacent to the first and second transparent layers; and 
 a seal formed from a barrier layer that hermetically seals the peripheral edge, wherein the barrier layer is coupled to the first and second transparent layers with the desiccant tape. 
 
     
     
       26. The optical component of  claim 25 , wherein the barrier layer comprises first and second metal layers that are respectively soldered to the first and second transparent layers. 
     
     
       27. The optical component of  claim 26 , wherein the barrier layer further comprises primer between the first and second metal layers and the first and second transparent layers. 
     
     
       28. The optical component of  claim 27 , wherein the first and second metal layers comprise copper foil layers. 
     
     
       29. The optical component of  claim 25 , wherein the barrier layer comprises a single soft metal foil layer. 
     
     
       30. The optical component of  claim 25 , wherein the barrier layer comprises first and second metal layers that are respectively attached to the first and second transparent layers with only the desiccant tape.

Description:
This application claims the benefit of U.S. provisional patent application No. 63/407,504, filed Sep. 16, 2022, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to electronic devices, and, more particularly, electronic devices with optical components. 
     BACKGROUND 
     Electronic devices may have optical components. For example, electronic devices may have waveguides and other structures that are formed from transparent materials. These materials may be susceptible to chemical or moisture-induced degradation if exposed to excess moisture. Additionally, these materials may contain volatile species which induce degradation if they leave the system. 
     SUMMARY 
     An electronic device may have a support structure that supports one or more optical components. Each optical component may have first and second transparent layers such as first and second glass layers. The glass layers may have outer surfaces that face away from each other and inner surfaces that face towards each other. A moisture-sensitive polymer layer (e.g., an organic polymer layer) may be formed between the inner surfaces of the glass layers. 
     Along the periphery of each optical component, a moisture barrier may be formed to protect the polymer material of the polymer layer. The moisture barrier may be supported by a buffer member, and desiccant material may be formed adjacent to the moisture barrier to provide additional protection to water ingress. 
     The moisture barrier may provide a hermetic seal that extends between the first and second glass layers. The seal may include one or more metal layers that are coupled to the first and second glass layers. For example, glass prism rings may be coupled to the first and second glass layers (e.g., through welding) and metal may be coupled to the prism rings. The one or more metal layers may then be bonded to the metal on the prism rings, such as through soldering, to seal the metal layers to the first and second glass layers. 
     Additionally or alternatively, dark deposition layers may be used. The dark deposition layers may be attached to the glass layers and may prevent stray light from scattering through the optical component. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a cross-sectional side view of an illustrative electronic device in accordance with some embodiments. 
         FIG.  2    is a front view of an illustrative optical component with a peripheral seal in accordance with some embodiments. 
         FIG.  3    is a cross-sectional view of an illustrative peripheral seal having multiple metal layers coupled to prism rings on an optical component in accordance with some embodiments. 
         FIG.  4    is a cross-sectional view of an illustrative prism ring with a laser-welding window in accordance with some embodiments. 
         FIGS.  5 A- 5 E  are cross-sectional views of illustrative prism rings that may be used to attach a peripheral seal to an optical component in accordance with some embodiments. 
         FIG.  6    is a cross-sectional view of an illustrative peripheral seal having a single metal layer coupled to prism rings on an optical component in accordance with some embodiments. 
         FIG.  7    is a cross-sectional view of an illustrative peripheral seal having multiple metal layers coupled to rectangular prism rings on an optical component in accordance with some embodiments. 
         FIG.  8    is a cross-sectional view of an illustrative peripheral seal having multiple metal layers coupled to metal directly on an optical component in accordance with some embodiments. 
         FIG.  9    is a cross-sectional view of an illustrative peripheral seal having dark deposition layers on an optical component in accordance with some embodiments. 
         FIG.  10    is a side view of an illustrative metal layer that may be used in an optical component in accordance with some embodiments. 
         FIG.  11    is a side view of an illustrative low temperature oxide layer that may be used in an optical component in accordance with some embodiments. 
         FIG.  12    is a cross-sectional view of an illustrative peripheral seal having multiple metal layers coupled to an optical component with desiccant tape in accordance with some embodiments. 
         FIG.  13    is a cross-sectional side view of an illustrative peripheral seal having multiple metal layers coupled to an optical component using tape and a primer in accordance with some embodiments. 
         FIG.  14    is a cross-sectional side view of an illustrative peripheral seal having multiple metal layers coupled to an optical component using only tape in accordance with some embodiments. 
         FIG.  15    is a cross-sectional side view of an illustrative seal having a single metal layer coupled to an optical component using tape in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device may have housing structures. The housing structures, which may sometimes be referred to as support structures, may be used to support and/or enclose device components such as batteries, displays, integrated circuits, sensors, other circuitry, and optical components. Examples of optical components that may be used in the electronic device include lenses and lenses with embedded waveguides, optical devices with sensitive coatings, displays such as liquid crystal displays (e.g., displays in which arrays of liquid crystal pixels are sandwiched between inner and outer glass layers and polarizers), organic light-emitting diode displays (e.g., displays with organic light-emitting diode pixels sandwiched between glass layers or other layers), and/or other optical elements. The housing structures of the device may be configured to be mounted on a stand or in a frame, may be configured to rest on a desktop or other surface, or may be configured to be worn on a body part of a user (e.g., a wrist, arm, head, or other body part). During operation, an electronic device may use sensors and other circuitry to gather user input and other data and may use displays and other output devices to provide output for a user. 
     A cross-sectional view of a portion of an illustrative electronic device is shown in  FIG.  1   . As shown in  FIG.  1   , electronic device  10  may have one or more optical components (sometimes referred to as optical elements) such as optical component  20 . Each optical component  20  may be supported by housing  18 . Housing  18  may be a wearable housing or other suitable housing. Housing  18  may be formed from polymer, metal, and/or other suitable materials. Housing  18  may have one or more portions that are attached to optical component  20  to support optical component  20  during use of device  10  by a user. 
     In the example of  FIG.  1   , optical component  20  has a layer of polymer (e.g., a polyurethane-based polymer or other polymer) such as polymer layer  14 . Layer  14  may be sandwiched between a first transparent substrate (layer)  12  and an opposing second transparent substrate (layer)  12 . Substrates  12  may be transparent layers that each have an outwardly facing surface and an inwardly facing surface. The outwardly facing surfaces of substrates  12  may face away from each other. The inwardly facing surfaces of substrates  12  may face each other. In some embodiments, pixels or other structures may be sandwiched between substrates  12 . Illustrative configurations in which a polymer layer such as layer  14  is sandwiched between substrates  12  are sometimes described as an example. 
     Substrates  12  may be formed from glass (e.g., strengthened glass, ceramic glass, high index of refraction glass, and/or other layers of glass), transparent crystalline material such as sapphire, transparent ceramic, transparent polymer, and/or other transparent substrate material. In an illustrative configuration, which may sometimes be described herein as an example, substrates  12  are glass substrates (sometimes referred to as glass layers or glass members). The inner and outer surfaces of each substrate  12  may have planar areas (e.g., areas that lie in the X-Y plane of  FIG.  1   ) and/or may have areas characterized by curved cross-sectional profiles (e.g., convex and/or concave areas). In an illustrative configuration, the outwardly facing surface of one of substrates  12  may be fully or partly convex whereas the outwardly facing surface of the other of substrates  12  may be fully or partly concave. Substrates  12  may be coated with one or more layers of optical coatings to alter their reflectance spectra, absorption spectra, and/or transmission spectra. 
     Optical component  20  may serve as a lens that passes light (e.g., light traveling along the Z axis of  FIG.  1   ). The lens may form a waveguide that transports image light from a display (e.g., image light may be transported within the waveguide along a direction lying in the X-Y plane in the example of  FIG.  1   ). During fabrication of optical component  20 , polymer layer  14  may be processed to form structures for displays or other optical structures such as optical structure  16 . 
     Polymer layer  14  may be sensitive to water. To prevent degradation of polymer layer  14  and structure  16  due to exposure to moisture in the environment, layer  14  may be hermetically sealed. In particular, the periphery of optical component  20  may be provided with a hermetic seal. The hermetic seal may prevent ingress of environmental contamination into layer  14  and may prevent egress of volatile compounds and/or moisture from layer  14  to the exterior region surrounding component  20 , thereby helping to prevent degradation to layer  14 . An illustrative seal, such as a hermetic seal, is shown in  FIG.  2   . 
     As shown in  FIG.  2   , seal  22  may run along the periphery of element  20  to prevent moisture ingress at any location on the edge of element  20 . Element  20  of  FIG.  2    has an oval footprint, but may, in general, have any suitable shape (e.g., a rectangular outline, a circular outline, a teardrop outline, an outline with a combination of straight and curved peripheral edges, and/or other suitable shape). Seal  22 , which may sometimes be referred to as a moisture barrier seal or moisture seal, may be formed from one or more barrier layers that are impervious to moisture and/or other structures that provide structural support, adhesion, seam sealing, etc. Seal  22  may, for example, be formed from one or more metal layers that are coupled to the upper and lower transparent layers (e.g., glass layers) of  FIG.  1   . To seal the one or more metal layers to element  20 , additional glass layers (e.g., prisms) may be provided on the upper and lower transparent layers, metal may be sputtered on the additional glass layers, and the one or more metal layers may be soldered to the sputtered metal. An example of an illustrative seal coupled to an optical element is shown in  FIG.  3   . 
     As shown in  FIG.  3   , optical component  20  may have first and second substrates  12 . Polymer layer  14  may be formed between substrates  12 . When left unprotected, moisture can enter polymer layer  14  at peripheral edge (e.g., the edge adjacent to layer  23 ) of component  20 . To hermetically seal component  20  and thereby protect layer  14  from moisture ingress, seal  22  may be formed along the peripheral edge and may run around the entire periphery of component  20  as shown in  FIG.  2   . 
     In the example of  FIG.  3   , seal  22  includes an elastomeric buffer member such as buffer  23  that supports moisture barrier layer  24  (sometimes referred to as a hermetic barrier layer, environmental barrier layer, or barrier layer). Barrier layer  24  in the example of  FIG.  3    includes a first portion formed from barrier layer  24 A and a second portion formed from barrier layer  24 B. Layers  24 A and  24 B are joined at bond  26  (e.g., using solder, laser welds or other welds, adhesive, and/or other bond mechanisms that bond the mated surfaces of layers  24 A and  24 B together). In some embodiments, bond  26  may be formed by soldering layers  24 A and  24 B together, such as by using laser jet welding. By attaching layers  24 A and  24 B together in this way, layers  24 A and  24 B form a unified moisture barrier layer for seal  22  (layer  24 ). 
     Layers  24 A and  24 B may be metal layers. For example, layers  24 A and  24 B may be metal foils, such as aluminum foil layers. In general, any desired metal, or other desired materials, such as polymer, may be used to form layers  24 A and  24 B. Moreover, layers  24 A and  24 B may be plated with plating  25 A and  25 B, which may be nickel and/or gold (e.g., through an electroless nickel immersion gold (ENIG) process), as examples. In one illustrative embodiment, layers  24 A and  24 B may be coated using an ENIG process with 1-3 microns of nickel and 50-70 nm of gold. In general, however, any desired thicknesses may be used. 
     Alternatively, layers  24 A and  24 B may be coated (e.g., plated or covered with foil) with a desired metal, such as nickel, gold, or silver, using any other desired process, such as cold rolling. In some embodiments, layers  24  may be plated with silver or gold that is between 20 and 50 microns thick. Alternatively, layers  24  may be coated with copper foil that is approximately 10 microns thick. However, these thicknesses and materials are merely illustrative. In general, layers  24 A and  24 B may be coated or plated with any desired material. By plating layers  24 A and  24 B, solder  26  may more effectively bond layers  24 A and  24 B, the plating may also be used to couple layers  24 A and  24 B to transparent layers  12 , and the plating may protect layers  24 A and  24 B from damage during forming (e.g., stamping) during manufacturing. Plating  25 A and  25 B may be omitted, however, if desired. 
     To seal the peripheral edge of polymer layer  14 , layer  24  may be bonded over the edge by attaching a first edge of layer  24  to a first of substrates  12 , and by attaching an opposing second edge of layer  24  to a second of substrates  12 . Moreover, to create a strong seal using a bond that does not damage substrates  12 , glass prisms  28 A and  28 B may be coupled to layers  12 . For example, glass prisms  28 A and  28 B may be welded (e.g., by glass-to-glass welding in embodiments in which layers  12  are formed from glass) to layers  12  via welds  30 A and  30 B, respectively. In general, however, glass prisms  28  may be coupled to substrates  12  in any desired manner. 
     Coupling glass prisms  28 A and  28 B to layers  12  may allow metal layers  32 A and  32 B to be formed on the glass prisms. For example, metal layers  32 A and  32 B may be sputtered onto the glass prisms, formed by any desired physical vapor deposition process on the glass prisms, or otherwise coupled to the glass prisms. Metal layers  32 A and  32 B may be formed from titanium, tin, nickel, gold, or other desired metal. Regardless of the method in which metal layers  32 A and  32 B are formed on glass prisms  28 A and  28 B and the material of metal layers  32 , sealing/barrier layers  24 A and  24 B may be coupled to metal layers  32 A and  32 B, respectively. For example, as shown in  FIG.  3   , layers  24  may be soldered to metal  32  using bonds  34 A and  34 B (e.g., using laser solder jetting). 
     Desiccant material  36 A and  36 B may be interposed between glass prisms  28  and layers  24 . For example, desiccant material  36  may be a UV curable or pressure sensitive adhesive that include desiccant particles  37  (e.g., particles suspended in a matrix) that may absorb any water that makes it past barrier  24  or prisms  28 . In some embodiments, desiccant material  36  may be a desiccant tape. In this way, desiccant material  36  may provide additional protection of polymer layer  14  from moisture ingress. 
     Although bonds  26  and  34  have been described as being formed from solder, such as by a laser solder jetting process, bonds  26  and  34  may generally be formed from any desired bonding method. For example, bonds  26  and  34  may be formed by adhesive, solder, or other material for forming hermetically sealed joints. For example, bonds  26  and  34  may be formed using adhesives exhibiting low water vapor transmission rates such as polyisobutylene, epoxy, acrylic core tape, silver-based glue, fluorosilicones, or other adhesives, may be formed from metal solder based on indium-tin alloys or other metals, an/or may be formed by direct bonding in which the metal foil or other material of layer  24  is directly welded to the glass or other material of prisms  28 . If desired, layer  24  may be formed from solder foil, allowing solder bonds to be formed directly between foil surfaces (e.g., for soldered foil-foil joints and soldered foil-glass bonds). In some configurations, metal layers (e.g., strips of metal running along the periphery of component  20 ) are formed on the surfaces of substrates  12  to help allow solder bonds to be formed (e.g., to enhanced solder adhesion to substrates  12 ). 
     The thicknesses T 1  and T 3  of substrates  12  may be equal or the values of T 1  and T 2  may be different from each other. Thicknesses T 1  and T 3  may have values of 50 microns to 1000 microns or 100 microns to 400 microns or other suitable substrate thicknesses may be used in forming substrates  12  for element  20  (e.g., T 1  and/or T 3  may be at least 50 microns, at least 200 microns, at least 250 microns, less than 1000 microns, less than 700 microns, less than 350 microns, etc.). The thickness T 2  of polymer layer  14  may be 400 microns to 800 microns, at least 200 microns, at least 300 microns, at least 450 microns, less than 1200 microns, less than 750 microns, less than 600 microns, etc. 
     Layer  24  may be formed from a material such as metal foil (e.g., foil formed from aluminum, stainless steel, copper, nickel, and/or other metals), low water vapor transmission rate plastics such as polychlorotrifluoroethylene (PCTFE), or higher water vapor transmission rate plastics which are coated in a barrier film to reduce their water transmission, or other material(s) impermeable to moisture. The thickness of layer  24  may be less than 30 microns, 5-45 microns, at least 5 microns, at least 10 microns, at least 15 microns, at least 20 microns, at least 40 microns, less than 100 microns, less than 75 microns, less than 60 microns, or other suitable thickness. Layer  24  is preferably sufficiently thin to be bent into a desired shape for seal  22  while being sufficiently thick to exhibit desired strength while serving as a moisture barrier. Thinner foils tend to offer less resistance to thermal movement. Thicker foils tend to offer better handling and moisture barrier properties. Layer  24  preferably has a thickness and composition that allows layer  24  to be formed into a desired shape (e.g., under heat and/or pressure). As an example, layer  24  may have a thickness of less than 50 microns so that a desired three-dimensional shape may be embossed and/or otherwise molded (pressed) into layer  24 . 
     Buffer  23 , which may sometimes be referred to as a buffer member, support member, moisture barrier layer support, or support structure, may be formed from an elastomeric material or other compliant material. This allows buffer  23  to expand and contract to accommodate temperature-induced changes in the thickness of element  20  (e.g., the compliant nature of buffer  23  helps avoid stress due to possible mismatch between the coefficient of thermal expansion of each of the layers of element  20  and the coefficient of thermal expansion of buffer  23 ). 
     Examples of suitable materials for buffer  23  include silicone, polyisobutylene, polyvinylidene difluoride, neoprene, and nitril rubber. These materials may exhibit desirable properties such as an ability to match temperature-induced expansion in layer  14  (e.g., if the coefficient of thermal expansion of layer  14  is greater than 200 ppm/C, buffer  23  may exhibit an approximately matched coefficient of thermal expansion of 100-300 ppm/C), a low modulus of elasticity (e.g., less than 10 MPa), chemical compatibility with layer  14 , low solubility to liquid components in layer  14 , a low water vapor transmission rate, satisfactory adhesion to the edge of component  20 , minimal permanent deformation under applied stress (e.g., over a temperature range of −40 to 85C or other suitable temperature range), a glass transition temperature outside of the expected operating range of device  10  (e.g., a glass transition temperature of less than −40C or &gt;85C in one illustrative configuration), and a black appearance or other optically opaque appearance (e.g., less than 0.5% reflectivity) to help suppress stray light. Buffer  23  may have any suitable cross-sectional shape. 
     Layers  24 A and  24 B of seal  22  may have the same shape and size (e.g., so that layer  24  is symmetrical about bond  26 ) or layers  24 A and  24 B may have different shapes and/or sizes (e.g., so that the shape of layer  24  is asymmetrical). 
     The lateral dimension (width in the X-axis of  FIG.  3   ) of buffer  23  may be at least 400 microns, at least 800 microns, at least 1600 microns, less than 4000 microns, less than 2000 microns, less than 1100 microns, less than 550 microns, less than 350 microns, or other suitable width. The support that buffer  23  provides to layer  24  may help prevent damage to layer  24  during assembly and use of device  10 . If desired, buffer  23  may be omitted (e.g., so that an air gap is present between the inner surface of layer  24  and the peripheral edge of element  20 ). This can ease assembly of the structure. 
     The portion of housing  18  that supports element  20  may be mounted over an edge portion of layer  24  and/or may support element  20  at a portion of element  20  that is not overlapped by layer  24 . 
     Using a hermetic sealing arrangement of the type shown in  FIG.  3    or other hermetic sealing arrangement, layer  14  may be hermetically sealed (e.g., the entrance of moisture including moist substances such as sunscreen and perspiration, and/or other environmental contaminants into layer  14  from the exterior region surrounding layer  14  may be blocked and/or the egress of mobile compounds—e.g., moisture and/or small molecules and/or other mobile species—from within layer  14  to the exterior region surrounding layer  14  may be blocked). This helps preserve the integrity of layer  14  and prevents the performance of layer  14  from degrading. For example, the hermetic sealing of layer  14  may help preserve structures in layer  14 . 
     Optical performance can also be preserved by configuring the hermetic seal to preserve the shape of element  20  over a range of operating temperatures (e.g., by ensuring that the edge does not become overly compressed or expanded relative to the center of element  20  during temperature fluctuations. Consider, as an example, a scenario in which element  20  has planar layers  12  and  14  or other layers  12  and  14  that are characterized by a center thickness (e.g., a first thickness CT 1  that is measured in center of element  20 ) and an edge thickness (e.g., a second thickness CT 2  that is measured adjacent to the periphery of element  20 ). Optical performance can be maintained for element  20  by configuring the hermetic seal of element  20  so that the change in CT 1  over a given temperature range does not differ too much from the change in CT 2  over the same given temperature range. 
     With an illustrative configuration, buffer  23  is formed from a low modulus (less than 10 MPa, as an example) elastomeric polymer such as silicone that exhibits a coefficient of thermal expansion of 100-300 ppm/° C., layers  12  are glass layers, layer  14  is a polymer with thickness of about 600 microns and a lateral dimension of about 4-6 cm, prisms  28  are glass prisms, and layer  24  includes first and second L-shaped aluminum portions  24 A and  24 B (e.g., 10 micron thick foils of aluminum) plated with plating  25  (e.g., gold and/or nickel). 
     Although prisms  28  have been described as glass prisms, this is merely illustrative. In general, prisms  28  may be formed from any desired material, such as ceramic, sapphire, glass, polymer, or other desired material. Moreover, prisms  28  may have any desired shape. Examples of illustrative prisms  28  that may be used to couple layers  24  to substrates  12  are shown in  FIGS.  4  and  5   . 
     As shown in  FIG.  4   , prism  28  (which may correspond to either prism  28 A or  28 B of  FIG.  3   ) is triangular. Metal  31  may be formed on first surface  31  of prism  28 . Metal  31  may then be used to couple the seal (e.g., layers  24 A and  24 B) to substrate  12 . A second surface of prism  28  may be coupled to substrate  12  using welds (or other bonds)  30 . Third surface  29  may allow light (e.g., laser light) to pass when prism  28  is welded to substrate  12 . In other words, third surface  29  may form a laser window. By forming prism  28  as a triangle having a large third surface  29 , a large window may be provided to weld prism  28  to substrate  12 . In some embodiments, however, it may not be necessary or otherwise desirable to have third surface  29  be large. Moreover, in general, any desired shape may be used to form prism  28 . Some illustrative examples of various prisms that may be used are shown in  FIGS.  5 A- 5 E . 
     As shown in  FIG.  5 A , third surface  29  may be vertical (or near-vertical). Although there will be a smaller window through which light may pass to weld prism  28  to substrate  12 , first surface  31  may be longer, allowing for more metal  32  to be deposited. In this way, more metal may be provided for sealing layers  24  to bond. 
     As shown in  FIG.  5 B , prism  28  may be trapezoidal, having planar upper surface  33 , third surface  29 , and surface  31  on which metal  32  is deposited. Planar upper surface  33  may form a laser window through which prism  28  is welded to substrate  12 , if desired. 
     As shown in  FIG.  5 C , prism  28  may be rectangular, having planar upper surface  33  and side surfaces  29  and  31 . Metal  32  may be deposited over side surface  31  and a portion of planar upper surface  33 . The uncovered portion of planar upper surface  33  (e.g., the portion without metal  32 ) may form a laser window through which prism  28  is welded to substrate  12 , if desired. As an alternative to having metal extend over side surface  31  and a portion of planar upper surface  33 , metal  32  may extend only over a portion of upper surface  33 , if desired, as shown in  FIG.  5 D . 
     As shown in  FIG.  5 E , prism  28  may have a domes shape with surface  31 . Metal layer  32  may be formed on surface  31 . The uncovered portion of surface  31  (e.g., the portion without metal  32 ), may form a laser window through which prism  28  is welded to substrate  12 , if desired. 
     The shapes of prisms  28  shown in  FIGS.  4  and  5 A- 5 E  are merely illustrative. In general, prisms  28  may have any desired shapes. 
     Although  FIG.  3    describe layers  24  as being two separate L-shaped layers, this is merely illustrative. In general, layers  24  may have any desired shapes, such as curved shapes. Alternatively or additionally, seal  22  may include any desired number of layers, such as one layer, two layers, or more than two layers. An illustrative embodiment in seal  22  includes a single layer is shown in  FIG.  6   . 
     As shown in  FIG.  6   , seal  22  may include a single layer  42 . Layer  42  may be, for example, a metal foil layer, or other metal layer. Layer  42  may be coupled to both upper and lower substrates  12 . As shown in  FIG.  6   , an upper portion of layer  42  may be bonded (e.g., soldered) to metal  32 A, while a lower portion of layer  42  is bonded (e.g., soldered) to metal  32 B. Layer  42  may be plated, if desired, as indicated by plating  43 . For example, plating  43  may be nickel and/or gold plating, such as ENIG plating. However, this is merely illustrative. Metal layer  42  may not be plated, if desired. 
     Although  FIGS.  3 - 5    describe prisms  28  as having triangular shapes, this is merely illustrative. In general, prisms  28  may have any desired shapes, such as rectangular shapes, circular shapes, or other shapes. Alternatively, prisms  28  may be omitted (e.g., metal  32  may be formed directly on substrates  12 ). Illustrative embodiments in which prisms  28  are rectangular and omitted, respectively, are shown in  FIGS.  7  and  8   . 
     As shown in  FIG.  7   , prisms  44 A and  44 B may be rectangular prisms and be coupled to substrates  12 . For example, prisms  44 A and  44 B may be welded, adhesively bonded, or otherwise bonded to substrates  12  using bonds  30 A and  30 B, respectively. Prisms  44 A and  44 B may be formed from glass, ceramic, sapphire, polymer, or any other desired material. 
     Metal  32  may be formed on a surface of prisms  44 . In one example, as shown in  FIG.  7   , metal  32 A and  32 B may be formed on side surfaces of prisms  44 A and  44 B, respectively. In general, however, metal  32  may be formed on one or more desired surfaces of prisms  44 . 
     As discussed in connection with  FIG.  3   , layers  24 A and  24 B may be bonded to metal  32 A and  32 B using bonds  34 A and  34 B. Bonds  34 A and  34 B may be any desired bonds, such as solder (e.g., solder applied using laser solder jetting). 
     As shown in  FIG.  8   , prisms  28 / 44  may be omitted entirely, and metal  32 A and  32 B may be formed directly on upper and lower substrates  12 , if desired. As shown in  FIG.  8   , metal  32 A and  32 B may be welded (e.g., laser welded) to substrates  12  with welds  30 A and  30 B, respectively. Alternatively, welds  30 A and  30 B may be omitted, and metal  32 A and  32 B may be sputtered onto substrates  12  (e.g., using a physical vapor deposition sputtering process) or printed on substrates  12  (e.g., using a metal particle printing or paste printing method). In general, metal  32  may be applied to substrates  12  using any desired method. 
     Layers  24 A and  24 B may then be bonded to metal  32 A and  32 B using bonds  34 A and  34 B. For example, layers  24 A and  24 B may be soldered to metal  32 A and  32 B using laser solder jetting, soldering indium tin (InSn) solder (or other desired solder) to layers  24  and metal  32 , or other desired soldering process. 
     Whether or not prisms  28 / 44  are omitted, it may be desirable to include a dark peripheral member, such as an opaque masking layer, around the periphery of element  20 . An illustrative example of such a peripheral member that may be incorporated into an optical component is shown in  FIG.  9   . 
     As shown in  FIG.  9   , dark deposition layers  50 A and  50 C may be deposited on opposing sides of a first one of substrates  12  (e.g., upper substrate  12  in  FIG.  9   ), and dark deposition layers  50 B and  50 D may be deposited on opposing sides of a second one of substrates  12  (e.g., lower substrate  12  in  FIG.  9   ). Dark deposition layers  50 A,  50 B,  50 C, and  50 D, may be formed from amorphous silicon, may be formed from multiple layers (e.g., a first layer of Cr or CrC, and a second layer of W or WC), or may be formed from black nickel, as examples. In general, however, dark deposition layers  50 A-D may be formed from any suitable opaque material. 
     Dark deposition layers  50 A-D may have thicknesses of less than 1 micron, less than 1.5 microns, between 0.5 and 1 micron, or other suitable thicknesses. The presence of layers  50 A-D may prevent light that enters the edge of element  20  from scattering within element  20 . In other words, layers  50 A-D may block stray light (e.g., absorb the stray light) that enters element  20  from scattering within element  20  and exiting element  20  as undesirable light. 
     Layers  52 A and  52 B may be formed on dark deposition layers  50 A and  50 B, respectively. Layers  52 A and  52 B may include metal layers, a layer of silicon oxide, or a low temperature oxide, as examples. Layers  52 A and  52 B may have thicknesses of less than 1 micron, less than 1.5 microns, between 0.5 and 1 micron, or other suitable thicknesses. Illustrative examples of layers that may be used as layer  52 A and/or layer  52 B in  FIG.  9    are shown in  FIGS.  10  and  11   . 
     As shown in  FIG.  10   , stack  54  may include substrate  12 , solder  34 , and layer  52  (which may correspond to one or both of layers  52 A and/or  52 B of  FIG.  9   ) between substrate  12  and solder  34 . Although not shown in  FIG.  10   , dark deposition layer  50 A or  50 B may be formed between layer  52  and substrate  12 , if desired. 
     In the example of  FIG.  10   , layer  52  may include three metallic layers. In particular, layer  52  may include layer  56  formed from titanium and/or chromium, layer  58  formed from nickel and/or copper, and layer  60  formed from gold and/or silver. 
     Layer  52  may, in general, improve the adhesion of solder  34  to substrate  12 . In particular, solder  34  may bond to metal better than to substrate  12  (e.g., if substrate  12  is glass, solder  34  may only be bonded to the glass using Van der Waahl&#39;s forces, whereas solder  34  may bond to layer  52  via stronger metallic bonding). 
     Layer  56  may be an adhesive layer of titanium and/or chromium and may have a thickness of less than 200 nm, less than 250 nm, between 100 and 200 nm, or other suitable thickness to adhere the other layers to substrate  12 . The titanium, chromium, or other suitable material used for layer  56  may bond the material of substrate  12 , such as glass, better than the other metal layers in layer  52  and solder  34 . In some embodiments, the portion of substrate  12  in contact with layer  56  may be sanded to further improve the adhesion of layer  56  to substrate  12 . In this way, layer  56  may improve the adhesion of layer  52  and solder  34  to substrate  12 . 
     Layer  58  may be a layer to promote the adhesion of solder  34  and may be formed from nickel and/or copper with a thickness of less than 500 nm, less than 550 nm, between 400 and 500 nm, or other suitable thickness to adhere solder  34  to layer  52 . Finally, layer  60  may be a layer that minimizes surface oxidation of layer  52  (e.g., by preventing moisture ingress onto substrate  12 ) and that allows fluxless soldering, and may be formed from silver or gold. 
     The materials discussed in connection with layers  56 ,  58 , and  60  of layer  52  are merely illustrative. In general, any suitable layers, such as a stack of metal layers, may be used to improve the adhesion of solder  34  to substrate  12  and/or to protect substrate  12  from environmental conditions. 
     As an alternative to using metal layers  56 ,  58 , and  60  to form layer  52 , a low temperature oxide layer may be used. In the illustrative example of  FIG.  11   , layer  52  may be formed from silicon oxide or another suitable SiO x N y  low temperature oxide (LTO)  62 . When applied to substrate  12  and/or a dark deposition layer (e.g., dark deposition layer  50 ), local defects may be formed on the O or N components of the LTO  62 , which may create lone pairs that may covalently bond with the indium in solder  34  (e.g., InSn, InSnBi, or other indium-based solder). These bonds are stronger than bonds between solder  34  and substrate  12 . In this way, LTO layer  62  may improve the adhesion between solder  34  and substrate  12 . 
     Returning to  FIG.  10   , the presence of dark deposition layers  50 A and  50 B between substrates  12  and layers  52 A and  52 B may reduce stress on substrates when layers  52 A and  52 B are applied to substrates  12 . In some embodiments, for example, dark deposition layers  50 A and  50 B may have greater thicknesses than dark deposition layers  50 C and  50 D to reduce the stress applied to substrates  12 . However, this is merely illustrative. In some embodiments, dark deposition layers may be applied only on inner surfaces of substrates  12  (e.g., only dark deposition layers  50 C and  50 D may be present). In general, however, one or more dark deposition layer(s) may be formed on any suitable surface(s) of substrates  12 . 
     Although the previous embodiments have shown layers  24  bonded to metal  32  or  52 , this is merely illustrative. In some embodiments, metal  32  or  52  may be omitted. An illustrative embodiment in which metal  32  or  52  is omitted, and layers  24  are bonded to substrates  12  using desiccant tape and solder, is shown in  FIG.  12   . 
     As shown in  FIG.  12   , desiccant tape  36 A and  36 B may respectively couple layers  24 A and  24 B to substrates  12 . In particular, desiccant tape  36  may have an inner surface that is applied to substrate  12  and an outer surface that is applied to layer  24 . Moreover, solder  46 , which may be indium tin solder or other desired solder, may be used solder layers  24  to substrates  12 . If desired, glue  47  may be applied over solder  46 . 
     While  FIG.  12    shows solder  46  bonding layers  24  to substrates  12 , solder  46  may be omitted, if desired. In some embodiments, therefore, desiccant tape  36  may bond layers  24  to substrates  12  without the use of additional bonding. Alternatively, bonds other than solder  46 , such as bonds  34 , may be used in bonding layers  24  to substrates  12 . 
     Alternatively or additionally, layers  24  may be bonded to substrates using tape and primer. An illustrative example is shown in  FIG.  13   . 
     As shown in  FIG.  13   , tape  36 A and  36 B, which may be desiccant tape or other suitable tape may bond layers  24  to primer  64 A and  64 B. In the example of  FIG.  13   , layers  24  may be, for example, copper foil. For example, the copper foil may be pre-reduced by formic acid. The use of pre-reduced copper foil may improve the wetting, bonding, and sealing of solder  34 . In general, however, any suitable material may be used to form layers  24 . Plating  25  may be applied to layers  24 , as shown in  FIG.  13   , or plating  25  may be omitted. In particular, if pre-reduced copper foil is used for layers  24 , plating  25  may be omitted if desired. 
     Primer  64  may provide less stress to layers  12  than metal layers (such as metal layers  52  of  FIG.  9   ). In general, any suitable primer may be used to form primer  64  and provide improved adhesion between layers  12 , and tape  36 /solder  34 . 
     However, primer  64  and/or solder  34  may be omitted, if desired. As shown in illustrative  FIG.  14   , for example, layers  24  may be coupled to layers  12  with only tape  36 . In particular, by omitting primer  64  and solder  34 , layers  24  (which may be, for example, copper foil without plating  25 ) may be attached to layers  12  more easily. 
     Tape  36  may be desiccant tape (as shown in  FIG.  14   ) and/or may be ultraviolet-curable and/or thermo-curable. The bold-line thickness of tape  36  may be less than 20 microns, less than 25 microns, less than 15 microns, or other suitable thickness. Moreover, tape  36  may have a bonding flowability of at least 20%, at least 25%, or at least 15%, as examples, and may have a modulus of elasticity of at least 10 MPa, at least 8 MPa, or other suitable modulus. By having a high flowability, defects may be minimized within tape  36 , which in turn may minimize moisture ingress through tape  36  that could otherwise reach and damage layer  14 . Additionally, tape  36  may have a high tensile and shear strength against a spring back force from layer  24 , which may prevent/reduce delamination of tape  36  from layer  24  and/or buffer  23 . Moreover, tape  36  may bond layers  24  to layers  12  while reducing defects that may otherwise occur in layers  12  from the stress applied by layers  24 . In other words, tape  36  may reduce the stress that would otherwise be applied to layers  12  by layers  24 . In this way, tape  36  may bond layers  24  to layers  12 , while reducing risks of damage to layers  24 , buffer  23 , and/or layers  12 . 
     Although layers  24  have been described as two separate layers, this is merely illustrative. In some embodiments, a single layer  24  may be applied to an edge of layers  12 . An illustrative example is shown in  FIG.  15   . 
     As shown in  FIG.  15   , layer  24  may be applied to the edge of layers  12 . Layer  24  of  FIG.  15    may be a plated metal layer (e.g., a metal foil layer  24  plated with plating  25 ), may be a single layer of copper foil (or foil of another metal) without plating  25 , or may be a soft metal foil (e.g., without plating  25 ), as examples. Suitable soft metal foils that may be used for layer  24  include tin (Sn), indium (In,) InSn, or SAC305 (e.g., a lead-free alloy that contains 96.5% tin, 3% silver, and 0.5% copper), as examples. 
     By forming layer  24  from a single layer, such as a single soft metal foil, the foil-to-foil seals may be reduced (e.g., the single layer may only need to be attached end-to-end at one portion along the periphery of layers  12 ). Moreover, the single soft metal foil may be repulsed from layers  12  less than multiple layers. In this way, a single soft metal foil layer (or other single layer) may be used to surround the edge of layers  12 . 
     Device  10  may be operated in a system that uses personally identifiable information. It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users. 
     The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20230829
Publication Date: 20241203
Grant Date: 20241203
Priority Date: 20220916
Inventors: LIN, WEI
FU, Boyi
GUPTA, NATHAN K
Assignee: APPLE INC
CPC Classifications: [{"code": "B32B17/1022", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B2551/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B17/1077", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B2457/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B17/10036", "inventive": true, "first": false, "tree": "[]"}, {"code": "B23K1/0016", "inventive": true, "first": false, "tree": "[]"}, {"code": "B23K2101/36", "inventive": false, "first": false, "tree": "[]"}, {"code": "B23K2103/54", "inventive": false, "first": false, "tree": "[]"}, {"code": "B23K26/21", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/0093", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C17/3681", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C27/042", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C27/08", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B2307/7265", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2307/7375", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2307/7376", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2307/30", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03B23/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "B23K1/0056", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B17/10348", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B17/10165", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B2551/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2457/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B17/10036", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B17/1077", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B17/10302", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B17/10302", "inventive": true, "first": true, "tree": "[]"}, {"code": "B32B17/1022", "inventive": true, "first": true, "tree": "[]"}, {"code": "B32B2551/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2457/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B17/1077", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B17/1022", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B17/10036", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B17/10302", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 90245140