PATENT DOCUMENT

Publication Number: US-12202245-B2
Application Number: US-202218083135-A
Country: US
Kind Code: B2

Title: Laminated polymer windows

Abstract:
A system may have structure. The structures may include laminated structures formed by attaching inner and outer layers together with a layer of adhesive. The inner and outer layers in a structure may be formed from polymer such as polycarbonate. Forming the structure layers from polymer may allow the structure to have desired curvature. To improve safety and/or acoustic performance of the structure, the inner and outer structure layers may be formed from different materials. The outer polymer layer may be formed from polycarbonate and the inner polymer layer may be formed from a more brittle polymer such as polymethyl methacrylate (PMMA).

Claims:
What is claimed is: 
     
       1. A window, comprising:
 an inner polymer layer having a first Young&#39;s modulus; 
 an outer polymer layer having a second Young&#39;s modulus that is less than the first Young&#39;s modulus; 
 an adhesive layer that attaches the inner polymer layer and the outer polymer layer together, wherein the adhesive layer has a third Young&#39;s modulus that is less than the first Young&#39;s modulus and the second Young&#39;s modulus; 
 a hard coating, wherein the outer polymer layer is interposed between the hard coating and the inner polymer layer; and 
 a thermal coating, wherein the adhesive layer is interposed between the thermal coating and the inner polymer layer. 
 
     
     
       2. The window in  claim 1 , wherein the inner polymer layer has a greater thickness than the outer polymer layer. 
     
     
       3. The window in  claim 1 , wherein the inner polymer layer is formed from polymethyl methacrylate (PMMA) and wherein the outer polymer layer is formed from polycarbonate. 
     
     
       4. The window in  claim 1 , wherein the outer polymer layer has a transparent portion and an integral opaque portion that forms a ring around the inner polymer layer. 
     
     
       5. The window defined in  claim 1 , wherein the outer polymer layer is formed from polycarbonate. 
     
     
       6. The window defined in  claim 5 , wherein the inner polymer layer is formed from polycarbonate. 
     
     
       7. The window defined in  claim 5 , wherein the inner polymer layer is formed from a different material than the outer polymer layer. 
     
     
       8. The window defined in  claim 1 , wherein the inner polymer layer has a first thickness and wherein the outer polymer layer has a second thickness that is different than the first thickness. 
     
     
       9. The window defined in  claim 8 , wherein the first thickness is greater than the second thickness. 
     
     
       10. The window defined in  claim 1 , further comprising:
 an optical layer that is interposed between the inner polymer layer and the outer polymer layer. 
 
     
     
       11. The window defined in  claim 1 , wherein the outer polymer layer has a transparent portion and an opaque portion, wherein the opaque portion is formed in a ring around a periphery of the outer polymer layer and defines a central opening, and wherein the inner polymer layer is formed in the central opening. 
     
     
       12. The window defined in  claim 11 , further comprising:
 adhesive that attaches the opaque portion of the outer polymer layer to a system body, wherein the opaque portion of the outer polymer layer is interposed between the adhesive and the transparent portion of the outer polymer layer. 
 
     
     
       13. A window, comprising:
 an inner polymer layer having a first Young&#39;s modulus; 
 an outer polymer layer having a second Young&#39;s modulus that is less than the first Young&#39;s modulus; and 
 an adhesive layer that attaches the inner polymer layer and the outer polymer layer together, wherein the adhesive layer has a third Young&#39;s modulus that is less than the first Young&#39;s modulus and the second Young&#39;s modulus and wherein the outer polymer layer has a curved cross-sectional profile and a maximum surface strain that is greater than 4%. 
 
     
     
       14. The window defined in  claim 13 , wherein the outer polymer layer has compound curvature. 
     
     
       15. A window comprising:
 an inner polymer layer; 
 an outer polymer layer, wherein the outer polymer layer has a transparent portion and an opaque portion, the opaque portion is formed in a ring around a periphery of the outer polymer layer and defines a central opening, and the inner polymer layer is formed in the central opening; 
 an adhesive layer that is interposed between the inner polymer layer and the outer polymer layer; and 
 additional adhesive attached to the outer polymer layer, wherein the opaque portion of the outer polymer layer is interposed between the additional adhesive and the transparent portion of the outer polymer layer. 
 
     
     
       16. The window defined in  claim 15 , wherein the outer polymer layer has compound curvature. 
     
     
       17. The window defined in  claim 15 , wherein the outer polymer layer has a curved cross-sectional profile and a maximum surface strain that is greater than 4%.

Description:
This application claims priority to U.S. provisional patent application No. 63/311,340, filed Feb. 17, 2022, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to structures that pass light, and, more particularly, to windows. 
     BACKGROUND 
     Windows are used in buildings and vehicles. Windows may be formed from glass or other transparent material. 
     SUMMARY 
     A system such as a building or automobile may have windows. The windows may include laminated windows formed by attaching inner and outer window layers together with a layer of polymer adhesive. 
     The inner and outer window layers in a window may be formed from polymer such as polycarbonate. Forming the window layers from polymer may allow the window to have desired curvature. 
     To improve safety and/or acoustic performance of the window, the inner and outer window layers may be formed from different materials. As one example, the outer polymer layer may be formed from polycarbonate and the inner polymer layer may be formed from a more brittle polymer such as polymethyl methacrylate (PMMA). 
     The outer polymer layer may optionally have an opaque portion formed around the periphery of the window. This may allow the vehicle body to be adhered to the less brittle outer polymer layer rather than a more brittle inner polymer layer. The inner polymer layer may be formed in a central opening defined by the opaque portion of the outer polymer layer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a top view of an illustrative system with a window in accordance with an embodiment. 
         FIG.  2    is a cross-sectional side view of an illustrative laminated polymer window in accordance with an embodiment. 
         FIG.  3    is a graph showing deceleration over time for different window types in accordance with an embodiment. 
         FIG.  4    is a cross-sectional side view of an illustrative laminated polymer window with inner and outer layers formed from different materials in accordance with an embodiment. 
         FIG.  5    is a cross-sectional side view of an illustrative laminated polymer window with an outer layer that has a ring-shaped opaque portion in accordance with an embodiment. 
         FIG.  6    is a top view of an illustrative laminated polymer window with an outer layer that has a ring-shaped opaque portion such as the window of  FIG.  5    in accordance with an embodiment. 
         FIG.  7    is a diagram of illustrative method steps for forming a polymer layer that has a ring-shaped opaque portion such as the outer layer in  FIG.  5    in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Systems may be provided with windows. For example, a vehicle or other system may have glass windows. Laminated glass structures (windows) may be formed by attaching two or more glass layers together with adhesive. In some configurations, glass layers may be molded to form curved shapes prior to lamination. Forming glass layers with desired curved shapes may cause excessive stress on the glass layers. This stress may result in the glass being insufficiently robust for certain applications. Glass forming of complex curved parts also presents challenges in terms of surface tolerance and optical properties (distortion). 
     Polymer layers may be used instead of glass to form windows such as laminated windows. The polymer layers may be capable of holding desired curved shapes while maintaining satisfactory mechanical strength. 
     The systems in which the windows are used may be buildings, vehicles, or other desired systems. Illustrative configurations in which the system is a vehicle such as an automobile may sometimes be described herein as an example. This is merely illustrative. Windows may be formed in any desired systems. 
     An illustrative system of the type that may include windows is shown in  FIG.  1   . System  10  may be a vehicle, building, or other type of system.  FIG.  1    is a top view of an illustrative vehicle  10 . In the example of  FIG.  1   , vehicle  10  is the type of vehicle that may carry passengers (e.g., an automobile, truck, or other automotive vehicle). Configurations in which vehicle  10  is a robot (e.g., an autonomous robot) or other vehicle that does not carry human passengers may also be used. Vehicles such as automobiles may sometimes be described herein as an example. 
     Vehicle  10  may be manually driven (e.g., by a human driver), may be operated via remote control, and/or may be autonomously operated (e.g., by an autonomous driving system or other autonomous propulsion system). Using vehicle sensors such as lidar, radar, visible and/or infrared cameras (e.g., two-dimensional and/or three-dimensional cameras), proximity (distance) sensors, and/or other sensors, an autonomous driving system and/or driver-assistance system in vehicle  10  may perform automatic braking, steering, and/or other operations to help avoid pedestrians, inanimate objects, and/or other external structures on roadways. 
     Vehicle  10  may include a body such as vehicle body  12 . Body  12  may include vehicle structures such as body panels formed from metal and/or other materials, may include doors  18 , a hood, side body panels, a trunk, fenders, a chassis to which wheels are mounted, a roof, etc. Windows (sometimes referred to as glazings) such as window  14  may be coupled to body  12  and may be configured to cover openings in body  12 . Windows may be formed in doors  18  and other portions of vehicle body  12  (e.g., on the sides of vehicle body  12 , on the roof of vehicle  10 , and/or in other portions of vehicle  10 ).  FIG.  1    shows a window  14  formed on a front F of vehicle  10  (e.g., a front windshield). Windows (e.g., window  14 ), doors  18 , and other portions of body  12  may separate interior region  20  of vehicle  10  from the exterior environment (e.g., exterior region  16 ) that is surrounding vehicle  10 . Doors  18  may be opened and closed to allow people to enter and exit vehicle  10 . Seats and other structures may be formed in the interior of vehicle body  12 . 
     Motorized window positioners may be used to open and close windows  14 , if desired. The windows in system  10  such as window  14  may include a front window mounted within an opening in body  12  at the front of a vehicle (e.g., a front windshield), a moon roof (sun roof) window or other window extending over some or all of the top of a vehicle, a rear window at the rear of a vehicle, and/or side windows on the sides of a vehicle. Window  14  may be flat or window  14  may have one or more curved portions. The area of each window  14  in system  10  may be at least 0.1 m 2 , at least 0.5 m 2 , at least 1 m 2 , at least 5 m 2 , at least 10 m 2 , less than 20 m 2 , less than 10 m 2 , less than 5 m 2 , or less than 1.5 m 2  (as examples). 
     Vehicle  10  may have automotive lighting such as one or more headlights (sometimes referred to as headlamps), driving lights, fog lights, daytime running lights, turn signals, brake lights, and/or other lights. In some cases, vehicle  10  may include an exterior display that is configured to display content at the exterior of the vehicle. 
     Vehicle  10  may have components  24 . Components  24  may include propulsion and steering systems (e.g., manually adjustable driving systems and/or autonomous driving systems having wheels coupled to body  12 , steering controls, one or more motors for driving the wheels, etc.), and other vehicle systems. Components  24  may include control circuitry and input-output devices. Control circuitry in components  24  may be configured to run an autonomous driving application, a navigation application (e.g., an application for displaying maps on a display), and software for controlling vehicle climate control devices, lighting, media playback, window movement, door operations, sensor operations, and/or other vehicle operations. For example, the control system may form part of an autonomous driving system that drives vehicle  10  on roadways autonomously using data such as sensor data. The control circuitry may include processing circuitry and storage and may be configured to perform operations in vehicle  10  using hardware (e.g., dedicated hardware or circuitry), firmware and/or software. Software code for performing operations in vehicle  10  and other data is stored on non-transitory computer readable storage media (e.g., tangible computer readable storage media) in the control circuitry. The software code may sometimes be referred to as software, data, program instructions, computer instructions, instructions, or code. The non-transitory computer readable storage media may include non-volatile memory such as non-volatile random-access memory, one or more hard drives (e.g., magnetic drives or solid-state drives), one or more removable flash drives or other removable media, or other storage. Software stored on the non-transitory computer readable storage media may be executed on the processing circuitry of components  24 . The processing circuitry may include application-specific integrated circuits with processing circuitry, one or more microprocessors, a central processing unit (CPU) or other processing circuitry. 
     The input-output devices of components  24  may include displays, light-emitting diodes and other light-emitting devices, haptic devices, speakers, and/or other devices for providing output. Output devices in components  24  may, for example, be used to provide vehicle occupants and others with haptic output, audio output, visual output (e.g., displayed content, light, etc.), and/or other desired output. The input-output devices of components  24  may also include input devices such as buttons, sensors, and other devices for gathering user input, for gathering environmental measurements, for gathering information on vehicle operations, and/or for gathering other information. The sensors in components  24  may include ambient light sensors, touch sensors, force sensors, proximity sensors, optical sensors such as cameras operating at visible, infrared, and/or ultraviolet wavelengths (e.g., fisheye cameras, two-dimensional cameras, three-dimensional cameras, and/or other cameras), capacitive sensors, resistive sensors, ultrasonic sensors (e.g., ultrasonic distance sensors), microphones, radio-frequency sensors such as radar sensors, lidar (light detection and ranging) sensors, door open/close sensors, seat pressure sensors and other vehicle occupant sensors, window sensors, position sensors for monitoring location, orientation, and movement, speedometers, satellite positioning system sensors, and/or other sensors. 
     During operation, the control circuitry of components  24  may gather information from sensors and/or other input-output devices such as lidar data, camera data (e.g., two-dimensional images), radar data, and/or other sensor data. This information may be used by an autonomous driving system and/or driver&#39;s assistance system in vehicle  10 . 
     Window  14  may be formed from one or more layers of transparent glass. However, it may be difficult to manufacture glass windows having desired curvature. Windows  14  may therefore instead be manufactured using one or more layers of clear polymer (e.g., polycarbonate, polymethyl methacrylate, etc.).  FIG.  2    is a cross-sectional side view of an illustrative window  14  formed from two polymer layers that are laminated together with adhesive. 
     As shown in  FIG.  2   , window  14  includes clear polymer layers  30  and  34  (sometimes referred to as outer layer  30  and inner layer  34  or outer polymer layer  30  and inner polymer layer  34 ). Clear polymer layers  30  and  34  may be formed from polycarbonate (PC), as one example. Outer layer  30  and inner layer  34  may be laminated together using a polymer layer such as interposed adhesive layer  32  (e.g., an adhesive layer with one surface bonded to the inwardly facing surface of outer window layer  30  and an opposing surface bonded to the outwardly facing surface of inner window layer  34 ). Adhesive layer  32  (sometimes referred to as polymer layer  32 , polymer interlayer  32 , adhesive polymer interlayer  32 , etc.) may be formed from polyvinyl butyral (PVB), ethylene-vinyl acetate (EVA), thermoplastic polyurethane (TPU), or any other desired material. Adhesive layer  32  may be an elastic adhesive layer with a Young&#39;s modulus that is lower than the Young&#39;s modulus of layers  30  and  34 . Adhesive layer  32  serves to keep polymer layers  30  and  34  together even in the event polymer layers  30  and  34  break. This enhances the safety of window  14  by mitigating the possibility of pieces of polymer layers  30  and  34  falling or otherwise becoming safety hazards (even during break events). Adhesive layer  32  may also prevent polymer layers  30  and/or  34  from breaking into large, sharp pieces during a break event. 
     Polymer layer  30  has a thickness  42  and polymer layer  34  has a thickness  44 . The window may have a total thickness  46 . Thicknesses  42  and  44  may be the same or may be different. Each one of thicknesses  42  and  44  may be greater than 1 millimeter, greater than 2 millimeters, greater than 3 millimeters, greater than 4 millimeters, greater than 5 millimeters, greater than 10 millimeters, less than 3 millimeters, less than 4 millimeters, less than 5 millimeters, less than 10 millimeters, between 1.5 millimeters and 6 millimeters, between 2 millimeters and 3 millimeters, etc. Total thickness  44  may be greater than 3 millimeters, greater than 4 millimeters, greater than 5 millimeters, greater than 6 millimeters, greater than 10 millimeters, greater than 20 millimeters, less than 6 millimeters, less than 10 millimeters, less than 20 millimeters, between 4 and 10 millimeters, etc. 
     In the example of  FIG.  2   , polymer layer  30  is an outer polymer layer with an outer surface S 1  and inner surface S 2 . Polymer layer  34  is an inner polymer layer with an outer surface S 3  and inner surface S 4 . In other words, polymer layer  30  is interposed between exterior  16  and polymer layer  34 . Polymer layer  34  is interposed between interior  20  and polymer layer  30 . Surface S 1  is interposed between exterior  16  and surface S 2 . Surface S 4  is interposed between interior  20  and surface S 3 . 
     The mechanical strength of window  14  may be provided primarily by polymer layers  30  and  34  as well as adhesive layer  32 . However, one or more additional functional layers may be included in window  14  if desired. The additional functional layers may be incorporated on one or more of surfaces S 1 , S 2 , S 3 , and S 4 . In  FIG.  2   , a hard coat  36  and ultraviolet light blocking coating  38  are formed on outer surface S 1  of polymer layer  30 . Hard coat  36  may be a thermally cured coating that provides scratch resistance for window  14 , as one example. Ultraviolet light blocking coating  38  may block ultraviolet light (e.g., more than 80%, more than 90%, more than 95%, more than 99%, etc.) from reaching interior  20 . In  FIG.  2   , a thermal coating  40  (e.g., a silver-based coating) is included on inner surface S 2  of outer polymer layer  30 . Thermal coating  40  (sometimes referred to as a thermally reflective coating) may block infrared light (e.g., more than 50%, more than 80%, more than 90%, more than 95%, more than 99%, etc.) to maintain thermal comfort in interior  20  of vehicle  10 . 
     The examples of functional layers shown in  FIG.  2    are merely illustrative. If desired, one or more of layers  36 ,  38 , and  40  may optionally be omitted from window  14 . Additionally, one or more additional functional layers may optionally be included in window  14 . For example, a masking layer such as a black masking layer may be included in window  14  (e.g., on surface S 2 , on surface S 3 , etc.) to hide attachment features, for cosmetic reasons, etc. Optional fixed and/or adjustable optical components may also be incorporated into window  14 . Each optical layer may be a fixed and/or adjustable optical layer providing fixed and/or adjustable amounts of opacity, polarization, reflection, color cast, haze, and/or other optical properties. In one illustrative configuration, an optical layer may be included between polymer layers  30  and  34  (e.g., instead of or in addition to functional layer  40  in  FIG.  2   ). The optical layer may be a light guide that receives light from a light source at the edge of the window. The light source  26  may, as an example, provide visible light that is guided across window  14  within the light guide by total internal reflection. Light-scattering structures may be provided in window  14  to extract some of the guided light from the light guide (e.g., inwardly to produce illumination for interior region  20  and/or outwardly). 
     Using polymer layers for the laminated window may allow for additional functional layers (such as those discussed above) to be integrated more easily (e.g., using overmolding). Mechanical alignment fixtures, seals, lighting components (for interior and/or exterior lighting), and/or display screens may all be more easily integrated into window  14  when the window is formed from polymer layers. 
     Adhesive layer  32  may have a refractive index that is matched (e.g., within 0.1, within 0.07, within 0.05, or within 0.03) to that of layers  30  and  34 . Layer  32  may, if desired, include polymer configured to provide sound dampening (e.g., a soft polyvinyl butyral sublayer or other acoustic film embedded within layer  32 ). 
     Each layer in window  14  (e.g., layers  36 ,  38 ,  30 ,  40 ,  32 , and  34 ) may be substantially transparent to visible light (e.g., having a transparency to visible light that is greater than 80%, greater than 90%, greater than 95%, greater than 99%, greater than 99.9%, etc.). Alternatively, in some arrangements one or more of the layers in window  14  may be made darker to improve the cosmetics of the window (e.g., reflections) and/or provide privacy to the occupant. 
     Window  14  in system  10  may be completely planar (e.g., the inner and outer surfaces of window  14  may be flat) and/or some or all of the windows in system  10  may have surface curvature. The inner and outer surfaces of each window may as an example, have compound curvature (e.g., non-developable surfaces characterized by curved cross-sectional profiles taken along the X and Z directions of  FIG.  2   ) and/or may have developable surfaces (surfaces with zero Gaussian curvature that can be flattened without distortion). 
     Curvature in window  14  may be characterized by surface strain (the percentage of stretch/compression in a local area to form a shape from flat) and/or radius of curvature (the radius of a circular arc that best approximates the curve at a given point). Window  14  (e.g., polymer layers  30  and/or  34 ) may have a maximum surface strain of greater than 3%, greater than 4%, greater than 5%, greater than 6%, greater than 8%, less than 10%, less than 8%, less than 7%, between 5% and 7%, between 2% and 8%, etc.). Window  14  (e.g., polymer layers  30  and/or  34 ) may have a minimum radius of curvature of less than 5 meters, less than 2 meters, less than 1 meter, less than 0.5 meters, less than 0.1 meters, less than 0.05 meters, greater than 0.05 meters, between 0.1 meters and 2 meters, etc. 
     Forming outer layer  30  and inner layer  34  of window  14  from polymer (as opposed to glass) may allow for window  14  to have greater curvature (e.g., a maximum surface strain of greater than 5%, as one example). However, care must be taken for window  14  to also meet safety requirements as well as acoustic targets. 
     Care may be taken to ensure that window  14  meets all applicable safety requirements and regulations. One safety criterion applicable to windows in an automobile is the head injury criterion (HIC). HIC is a measure of the likelihood of head injury arising from an impact. HIC is derived from measurements of one or more accelerometers mounted in a crash test dummy&#39;s head during testing. HIC may be calculated using the formula: [1/t 2 −t 1 ∫ t     1     t     2    adt] 2.5  (t 2 −t 1 ), where a is head acceleration and t 2 −t 1  is selected so as to maximize HIC. A higher HIC correlates to a higher probability of head injury. It is therefore desirable to reduce the HIC value for a window. 
     Various safety institutes may have differing requirements for HIC. However, it is generally desirable for the HIC of window  14  to be low. Depending upon the specific design, window  14  may have an HIC of less than 1700, less than 1000, less than 700, less than 650, less than 500, less than 400, less than 300, etc. 
     As previously mentioned, layers  30  and  34  of laminated window  14  may be formed from polymer such as polycarbonate instead of glass to allow window  14  to have desired curvature. However, using polycarbonate layers  30  and  34  may result in window  14  having an HIC that is higher than if a laminated glass window is used.  FIG.  3    is a graph of deceleration (-a) as a function of time (T) caused by different windows during a crash test. Profile  62  shows the deceleration when a glass laminated window is used (e.g., window  14  in  FIG.  2    when layers  30 / 34  are glass layers of a given thickness). Profile  64  shows the deceleration when a polycarbonate laminated window is used (e.g., window  14  in  FIG.  2    when layers  30 / 34  are polycarbonate layers of the same given thickness). 
     Glass layers may be more brittle than polycarbonate layers of the same thickness. During an impact event, the brittle glass layers may initially cause a spike in deceleration (as shown by profile  62 ) but then quickly break, which mitigates the applied deceleration for the remainder of the test. As shown by profile  64 , polycarbonate layers may be less brittle than glass and therefore may not break upon impact, resulting in a higher deceleration than glass after the initial spike of profile  62 . 
     To achieve target safety requirements (e.g., a target HIC) while maintaining the curved shapes enabled by the polycarbonate, thin layers of polycarbonate may be used. As an example, polycarbonate layers  30  and  34  in  FIG.  2    may each have a thickness (e.g., a uniform, central, and/or maximum thickness) that is less than 2.5 millimeters, less than 2.1 millimeters, less than 2.0 millimeters, less than 1.8 millimeters, less than 1.5 millimeters, etc. As another example, one or more fuse structures (e.g., a low thickness area that will preferentially break) may be integrated into the glazing to achieve target safety requirements. However, reducing the thickness of layers  30  and  34  in window  14  may reduce the acoustic performance of the window. In general, using thicker layers for layers  30  and  34  improves the noise-dampening properties of the window during operation of the vehicle. 
     To optimize safety performance and acoustic performance in window  14 , the inner layer of window  14  may be formed from a different material than the outer layer of window  14 . FIG.  4  is a cross-sectional side view of a window of this type. Window  14  in  FIG.  4    is similar to the window in  FIG.  2    and common components will not be described again in connection with  FIG.  4   . 
     In  FIG.  4   , window  14  includes an inner layer  48  that is formed from a different material than outer layer  30 . In one example, inner layer  48  is formed from polymethyl methacrylate (PMMA) whereas outer layer  30  is formed from polycarbonate (PC). Inner layer  48  may be formed from other polymer materials if desired (e.g., polystyrene, polyvinyl chloride, polyoxymethylene, etc.). 
     In  FIG.  4   , polymer layer  30  has a thickness  42  and polymer layer  34  has a thickness  44 . Thickness  44  may be greater than thickness  42 . The window may have a total thickness  46 . Each one of thicknesses  42  and  44  may be greater than 1 millimeter, greater than 2 millimeters, greater than 3 millimeters, greater than 4 millimeters, greater than 5 millimeters, greater than 10 millimeters, less than 3 millimeters, less than 4 millimeters, less than 5 millimeters, less than 10 millimeters, between 1.5 millimeters and 6 millimeters, between 2 millimeters and 3 millimeters, etc. Total thickness  44  may be greater than 3 millimeters, greater than 4 millimeters, greater than 5 millimeters, greater than 6 millimeters, greater than 10 millimeters, greater than 20 millimeters, less than 6 millimeters, less than 10 millimeters, less than 20 millimeters, between 4 and 10 millimeters, etc. Thickness  44  may be greater than thickness  42  by at least 0.1 millimeter, by at least 0.3 millimeters, by at least 0.5 millimeters, by at least 1 millimeter, by at least 2 millimeters, by at least 3 millimeters, by at least 5 millimeters, by between 0.1 and 5 millimeters, by between 0.5 and 2 millimeters, etc. Thickness  44  may be greater than thickness  42  by at least 5%, by at least 10%, by at least 20%, by at least 50%, by at least 100%, etc. Using a thicker inner layer  48  as in  FIG.  4    may improve the acoustic performance of window  14 . 
     As previously discussed in connection with  FIG.  3   , the brittleness of glass may improve the safety performance of window  14 . One way to characterize the brittleness of a material is through Young&#39;s modulus (a ratio of tensile stress to tensile strain). Young&#39;s modulus may also sometimes be referred to as tensile modulus. In general, materials with a higher Young&#39;s modulus tend to be more brittle and materials with lower Young&#39;s modulus tend to be less brittle. It should be understood that the magnitudes for Young&#39;s modulus of materials provided herein may be obtained using the same testing conditions (e.g., 1 millimeter/minute). Glass may have a Young&#39;s modulus between 50 GPa and 90 GPa. In contrast, polycarbonate may have a lower Young&#39;s modulus than glass (e.g., between 2 GPa and 3 GPa). 
     For comparison, adhesive layer  32  may be formed from a low-modulus material having a Young&#39;s modulus that is less than 5 GPa, less than 2 GPa, less than 1 GPa, less than 0.5 GPa, less than 0.3 GPa, greater than 0.1 GPa, between 0.1 GPa and 1 GPa, etc. The Young&#39;s modulus for adhesive layer  32  may be lower than that of layers  30  and  48 . 
     To make layer  48  more brittle and improve the safety performance of window  14 , layer  48  may be formed from a material with a higher Young&#39;s modulus than layer  30 . Layer  48  may be formed from PMMA with a Young&#39;s modulus of 5 GPa, as one example. 
     Layer  48  may have a greater Young&#39;s modulus than layer  30  by at least 0.1 GPa, at least 0.3 GPa, at least 0.5 GPa, at least 1 GPa, at least 2 GPa, at least 5 GPa, at least 20 GPa, between 0.3 GPa and 5 GPa, less than 20 GPa, etc. Layer  48  may have a greater Young&#39;s modulus than layer  30  by at least 5%, by at least 10%, by at least 20%, by at least 50%, by at least 100%, etc. 
     The example in  FIG.  4    of outer layer  30  being formed from polycarbonate and inner layer  48  being formed from PMMA is merely illustrative. This arrangement may sometimes be desirable to provide a durable outer layer. If desired, this arrangement may be switched (with a PMMA outer layer and a polycarbonate inner layer). In general, window  14  may be formed from two polymer layers. One of the polymer layers may have a first thickness and a first Young&#39;s modulus. The other polymer layer may have a second thickness that is greater than the first thickness (e.g., by at least 5%, by at least 10%, by at least 20%, by at least 50%, by at least 100%, etc.) and a second Young&#39;s modulus that is greater than the first Young&#39;s modulus (e.g., by at least 5%, by at least 10%, by at least 20%, by at least 50%, by at least 100%, etc.). The window may have a satisfactory HIC (e.g., lower than 1000, lower than 650, etc.), may have curvature (e.g., a maximum surface strain greater than 5%), and may have satisfactory acoustic performance (e.g., may have a total thickness that is greater than 5 millimeters, greater than 6 millimeters, etc.). 
     In the example of  FIG.  4   , window  14  is attached to body  12  of vehicle  10  by adhesive  70 . Adhesive  70  may be formed from urethane or any other desired material. In  FIG.  4   , adhesive  70  attaches inner layer  48  of window  14  directly to body  12 . In other words, inner surface S 4  of inner layer  48  is in direct contact with adhesive  70 . Adhesive  70  is in direct contact with inner layer  48  and body  12 . This example is merely illustrative. 
     Inner layer  48  may be more brittle than layer  30  (as previously discussed). In some cases, it may be undesirable to attach adhesive  70  directly to the more brittle inner layer  48 . In these cases, window  14  may optionally have an arrangement of the type shown in  FIG.  5   . Window  14  in  FIG.  5    is similar to the window in  FIG.  4    and common components will not be described again in connection with  FIG.  5   . 
     As shown in  FIG.  5   , outer layer  30  may be formed with a first portion  30 - 1  and an integral second portion  30 - 2 . First portion  30 - 1  may be formed from transparent polycarbonate and extends across the entire face of the window. The integral second portion  30 - 2  may be provided so that adhesive  70  may be attached to the less brittle polycarbonate layer  30  as opposed to the more brittle PMMA (or other polymer) inner layer  48 . Second portion  30 - 2  may include polycarbonate (or the same base material as portion  30 - 1 ). Second portion  30 - 2  may also include one or more additional materials such as acrylonitrile butadiene styrene (ABS). The additional material may optionally be used to provide a non-transparent color to portion  30 - 2 . Portion  30 - 2  may be, for example, a black (opaque) portion with a transparency of less than 50%, less than 30%, less than 10%, less than 5%, less than 1%, less than 0.1%, etc. Portion  30 - 2  therefore hides adhesive layer  70  from being visible through window  14  from exterior region  16 . 
       FIG.  6    is a top view of window  14  from  FIG.  5    in the Y-direction from the interior side of window  14 . As shown in  FIG.  6   , portion  30 - 2  of layer  30  may be formed in a ring that defines a central opening. Inner layer  48  is formed in (overlaps in the Y-direction) the central opening. A portion of adhesive layer  32  may be interposed between portion  30 - 2  and layer  48  (as shown in  FIGS.  5  and  6   ). Adhesive  70  may also be formed in a ring (e.g., with a similar footprint to portion  30 - 2 ). Adhesive  70  also defines a central opening, with inner layer  48  being formed in (overlapping) the central opening. 
     The example in  FIG.  6    of portion  30 - 2  and adhesive  70  being formed in a continuous ring that completely surrounds the periphery of window  14  is merely illustrative. If desired, portion  30 - 2  and/or adhesive  70  may have footprints of other shapes (e.g., with discrete sections that approximate a ring around the periphery without completely surrounding the periphery). Portion  30 - 2  and adhesive  70  may have approximately the same footprint (as shown in  FIG.  6   ) or may have different footprints (e.g., portion  30 - 2  may form a continuous ring whereas adhesive  70  has non-continuous, discrete sections that approximate a ring). In  FIG.  6   , the periphery of window  14  (and therefore portion  30 - 2  and adhesive  70 ) has a non-square rectangular shape. This example is merely illustrative. In general, window  14  may have any desired shape. 
       FIG.  7    is a diagram showing illustrative method steps that may be used to form a window of the type shown in  FIG.  5    (where the outer polymer layer has an integral additional portion that is attached directly to adhesive). During polymer molding operations, molding equipment may be used to form sheets of polymer with curved cross-sectional profiles. These molded window layers may be characterized by curved cross-sectional profiles and may have surfaces that are free of compound curvature (e.g., the window layers may have only developable surfaces), may have surfaces that are free of developable surface areas (e.g., the window layers may have surfaces with only compound curvature), and/or may have both one or more areas characterized by developable surfaces and one or more areas characterized by compound curvature. 
     As shown in  FIG.  7   , portion  30 - 1  of inner polymer layer  30  may be formed using heated furnace  80  and mold  82 . Mold  82  may be formed with a desired curved shape (that is imparted onto inner polymer layer  30 ). Mold  82  may be formed from a material such as graphite that can withstand high temperatures. During step  102 , injection compression molding (sometimes referred to as coining) may be used to form portion  30 - 1  of inner polymer layer  30 . 
     During injection molding, material is injected into a cavity formed by the mold. The cavity is completely filled during injection molding. During injection compression molding (as in step  102  of  FIG.  7   ), a cavity for portion  30 - 1  may be mostly but not entirely filled while at a lower pressure than during injection molding (e.g., while the mold is not entirely closed). Subsequently, the mold is clamped (closed) to form the final shape of the material. Injection compression molding has a much lower fill pressure than injection molding. This lower pressure may improve the optical properties of portion  30 - 1  at step  102  relative to if injection molding was used. 
     At step  104 , injection molding may be used to form portion  30 - 2  of layer  30 . Portion  30 - 2  may be opaque and therefore the optical properties of portion  30 - 2  may be less impactful than the optical properties of portion  30 - 1 . Accordingly, injection molding is used at step  104  instead of injection compression molding. As shown in  FIG.  7   , at step  104  portion  30 - 2  may be formed directly on portion  30 - 1  using mold  82 . Portion  30 - 2  may be formed in a ring around the periphery of portion  30 - 1  (as shown in the top view of  FIG.  6   , for example). 
     Portion  30 - 1  in  FIG.  7    is formed with a curved cross-sectional profile. Portion  30 - 2  in  FIG.  7    is also formed with a curved cross-sectional profile. 
     Finally, at step  106 , inner polymer layer  48  may be laminated to outer layer  30  using adhesive layer  32 . Inner polymer layer  48  is formed in a central opening defined by the ring shape of portion  30 - 2 . Inner polymer layer  48  may be planar (flat) as shown in the example of  FIG.  7   . Alternatively, inner polymer layer  48  may be formed (e.g., using an injection compression molding process similar to as shown in step  102 ) with desired curvature. The curved inner polymer layer  48  is then laminated to curved outer polymer layer  30  at step  106 . 
     The method for forming a laminated polymer window shown in  FIG.  7    is merely illustrative. In general, any desired method steps (e.g., injection molding, injection compression molding, lamination, compression molding, etc.) may be used to form laminated windows of the type shown in  FIGS.  2 ,  4 , and  5   . 
     To summarize, a system such as a vehicle (automobile) may include a laminated polymer window with an outer polymer layer and an inner polymer layer. In one possible arrangement, the outer polymer layer and the inner polymer layer may be formed from polycarbonate. In another possible arrangement, one of the polymer layers (e.g., the outer polymer layer) may be formed from polycarbonate whereas the other polymer layer (e.g., the inner polymer layer) may be formed from a different, more brittle material such as PMMA. The more brittle layer (e.g., the inner layer) may be thicker than the other polymer layer. The outer polymer layer may have an integrally formed portion that forms a ring around the inner polymer layer and that is in direct contact with adhesive. 
     It should further be noted that the inner polymer layer may be omitted from window  14  if desired. In this type of arrangement, a single polymer layer may form window  14 . The single polymer layer may be formed from polycarbonate, PMMA, or another desired material that provides desired safety performance, acoustic performance, and curvature. 
     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: 20221216
Publication Date: 20250121
Grant Date: 20250121
Priority Date: 20220217
Inventors: CONNOLLY, PAUL M
GOLKO, ALBERT J
Llamazares Domper, Arturo
KINGMAN, DAVID E
KRASS, DEREK C
GROSS, MARTIN
BARTHOMEUF, OLIVIER C
MASSCHELEIN, PETER F
UPRETI, YOGESH
Assignee: APPLE INC
CPC Classifications: [{"code": "B32B2605/006", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2369/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2333/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2307/412", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2307/41", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2250/24", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2250/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B37/182", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B37/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B33/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B27/365", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B27/308", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B27/08", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B3/26", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B1/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B7/022", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B2605/006", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2255/205", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2255/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B1/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B27/308", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B27/365", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B7/022", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B7/12", "inventive": true, "first": true, "tree": "[]"}, {"code": "B32B27/08", "inventive": true, "first": true, "tree": "[]"}, {"code": "B32B2605/006", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2369/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2333/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2307/412", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2307/41", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2250/24", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2250/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B37/182", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B37/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B33/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B27/365", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B27/308", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B27/08", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B7/022", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B3/26", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B1/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B7/12", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 85227424