BACKGROUND OF THE INVENTION

Field

[0001] The disclosure relates to laminates and applications of laminates.

Background

[0002] Laminates are materials made up of multiple layers. The choice of material and fabrication of the laminate can help obtain a resulting composite material with improved properties or characteristics like strength, stability, appearance or optical transmissivity.

[0003] One type of laminate can be transparent. This allows users to see through the laminate. Such laminates can be made of multiple layers including glass, ceramic, polymers, plastic, and other materials provided in a composite of thin film layers. In one application, the laminate includes a glass surface or substrate like a window pane or windshield. For example, additional layers of the laminate can be disposed on the glass surface to enhance the strength, stability, or appearance of the window pane or windshield.

[0004] Some attempts have been made to use a laminate to provide impact resistance from projectiles such as a rock or a bullet. As an example, but not by limitation, 3M Corp. offers a ballistic impact laminate that, per UL/ULC 752, offers limited impact resistance for an incident bullet. The laminate though is aimed at impact resistance and is inactive in that no control of its electrical or optical properties after application on a window is provided. As a second example, but not by limitation, Clear Armor, LLC offers a ballistic impact laminate that offers significant impact resistance per UL/ULC 752 for incident bullet(s) as well as bomb resistance certification of GSA, Level 1 & 2, from the National Institute of Justice. However, again, the forementioned example of ballistic impact laminate does not offer optical properties that can be changed by electrical control.

[0005] Other laminates are active in that optical properties can be changed through

electrical control but ignore impact resistance. US 2013/0127202 Al teaches the use of de-coupling of the glass and laminate as well as the use of multiple layers of laminate applied to different sides of glass to protect against asymmetrical impact(s). Additionally, US 2013/0127202 Al teaches that in addition to the use of multiple layers of laminate, one or more of the laminates may possess optical or electrical functionality but lacks any insight or suggestion for control of optical functionality.

[0006] In a smart window application Khaligh et al., "Silver nanowire transparent

electrodes for liquid crystal-based smart windows," Solar Energy Materials & Solar Cells 752:337-341 (2015) teaches that a polymer-dispersed liquid crystal (PDLC) smart window may be constructed using transparent electrodes made from silver nanowire deposits, as an alternative to expensive indium tin oxide (ITO). However, Khaligh fails to address and does not contemplate impact resistance or any control in response to an impact. Khaligh also does not face or handle PDLC degradation in constant sunlight, i.e. UV radiation, nor the effects from treatment of a surface that is potentially exposed to extreme heat and kinetic forces with respect to the potential for continued utility of opacity-changing characteristics after an impact.

BRIEF SUMMARY OF THE INVENTION

[0007] Embodiments of the present invention provide impact resistant, opacity-changing laminate devices and applications.

[0008] In one embodiment, an impact resistant, opacity-changing laminate device

includes a transparent impact resistant layer and an optically active element. The optically active element is disposed along an optical path relative to the impact resistant layer and configured to change from a first optical state to a second optical state more opaque than the first optical state in response to a projectile or other object incident on the impact resistant layer. In one embodiment, the optically active element is configured to gradually change from a first optical state to a second optical state in response to user input.

[0009] In exemplary embodiments, the transparent impact resistant layer includes one or more of the following materials: woven acrylic fiber, transparent ceramic fiber, polycarbonate, aluminum oxynitride, or combinations thereof.

[0010] In exemplary embodiments, the optically active element includes two electrically conductive layers separated by one or more layers of electro-optic material that change one or more of their optical properties in response to an electric field or current applied through the two electrically conductive layers. In embodiments, the optical properties that change in response to an applied electric field or current include transparency, polarization or wavelength transmissivity.

[0011] In exemplary embodiments, the electro-optic material includes one or more of the following materials: electrochromic material, electroluminescent material, photochromic material, thermochromic material, polymer-dispersed liquid crystal (PDLC), or suspended particle device (SPD) material.

[0012] In exemplary embodiments, the two electrically conductive layers include one or more of the following materials: indium tin oxide (ITO), tin oxide, zinc oxide, conductive polymers, graphene, carbon nanotubes, metallic grids, copper nanowires, silver nanowires, or combinations thereof.

[0013] In exemplary embodiments, the laminate device further includes a voltage source coupled to the two electrically conductive layers.

[0014] In exemplary embodiments, the laminate device further includes a controller coupled to the voltage source and configured to adjust the voltage level applied to the two electrically conductive layers. In additional embodiments, the laminate device includes a detector configured to detect when a projectile strains, impacts, or breaks at least one layer in the laminate device and generate a signal representative thereof for output to the controller. In embodiments, the controller is configured to adjust the voltage level in response to the detected signal to change the optical properties of one or more layers of electro-optic material.

[0015] In exemplary embodiments, the laminate device further includes a distributed, transparent impact sensor. In embodiments, the distributed, transparent impact sensor include a transparent conductor film deposited on a substrate, a transparent piezoelectric polymer layer, sandwiched between a pair of transparent electrodes. In exemplary embodiments, the transparent piezoelectric polymer layer includes poly(vinylidene fluoride) (PVDF). In exemplary embodiments, the laminate device further includes a discrete impact sensor.

[0016] In exemplary embodiments, the laminate device further includes a piezoelectric strain sensor layer that generates an electric current when a projectile strains, impacts, or breaks at least one layer in the laminate device and generates a signal representative thereof for output. [0017] In exemplary embodiments, the laminate device further includes a protective cover having one or more layers that provide electrical insulation and scratch-resistance disposed over the optically active element.

[0018] In exemplary embodiments, the laminate device further includes a pane disposed before the transparent impact resistant layer and the optically active element along a same optical path from an external environment to an internal environment. Suitably, the pane includes a windshield of a vehicle.

[0019] In further embodiments, the laminate device includes one or more additional layers that provide anti-reflection, UV blocking, IR blocking, selective wavelength reflecting, light emission, information display, self-cleaning, breakage sensing or touch sensing functionalities.

[0020] In exemplary embodiments, the transparent impact resistance layer is ballistic impact resistant.

[0021] In another embodiment, a method for obscuring an interior environment on one side of the impact resistant, opacity-changing laminate device in response to a projectile incident on a surface of the device is provided. The method includes detecting when an incident projectile strains, impacts, or breaks at least one layer in the laminate device and generating a signal representative thereof; and adjusting a voltage level or electric current in response to the detected signal to change the optically active element from the first optical state to the second optical state more opaque than the first state.

[0022] In a still further embodiment, a method for fabricating an impact resistant,

opacity-changing laminate device is provided. The method includes disposing a first electrically conductive layer on a transparent, impact resistance layer and disposing a second electrically conductive layer on a face of a protective cover. The method further includes arranging one or more layers of electro-optic material that change one or more of their optical properties in response to an electric field or current applied through the first and second electrically conductive layers. In some embodiments, the method further includes disposing on a substrate a face of the transparent, impact resistance layer opposite the first electrically conductive layer, whereby the substrate can be a pane on a windshield or window. [0023] Further embodiments, features, and advantages of the invention, as well as the structure and operation of the various embodiments, are described in detail below with reference to accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

[0024] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the present disclosure and, together with the description, further serve to explain the principles of the disclosure and to enable a person skilled in the relevant art to make and use the disclosure.

[0025] FIG. 1 is a cross-sectional diagram of a laminate device according to one

embodiment of the present invention.

[0026] FIG. 2 is a cross-sectional diagram of a laminate device with a controller

according to another embodiment of the present invention.

[0027] FIG. 3 is a flowchart a diagram of a method for obscuring an interior environment with a laminate device according to an embodiment of the present invention.

[0028] Further embodiments, features, and advantages of the invention, as well as the structure and operation of the various embodiments, are described in detail below with reference to accompanying drawings. The drawing in which an element first appears is typically indicated by the leftmost digit or digits in the corresponding reference number. In the drawings, like reference numbers may indicate identical or functionally similar elements.

DETAILED DESCRIPTION OF THE INVENTION

[0029] This disclosure provides impact resistant, opacity-changing laminate devices and applications. In one embodiment, this disclosure is directed to a transparent laminate designed to fortify optically transmissive materials against a projectile or other object impact while simultaneously allowing the user to control the level of transparency via application of an electric field or current. In a non-limiting example, the impact resistant, opacity-changing laminate devices can be used in a vehicle window to enhance projectile impact resistance and to enable the ability of the window to change transparency as desired - transparent while driving, opaque while parked. In another non-limiting example, the impact resistant, opacity-changing laminate devices can be used where a differential in impact resistance is needed. In a further non-limiting example, the impact resistant, opacity-changing laminate devices enable users to control the transparency of the glass with the press of a switch.

[0030] This specification discloses one or more embodiments that incorporate the

features of this invention. The disclosed embodiment(s) merely exemplify the invention. The scope of the invention is not limited to the disclosed embodiment(s). The invention is defined by the claims appended hereto.

[0031] The embodiment(s) described, and references in the specification to "some

embodiments," "one embodiment," "an embodiment," "an example embodiment," etc., indicate that the embodiment(s) described can include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is understood that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0032] References to spatial descriptions (e.g., "above," "below," "up," "down," "top,"

"bottom," etc.) made herein are for purposes of description and illustration only, and should be interpreted as non-limiting upon the screens, bases, substrates, methods and products of any process of the present invention, which can be spatially arranged in any orientation or manner.

[0033] Throughout the specification, use of the term "about" with respect to any quantity is contemplated to include that quantity. For example, "about 10 μιη" is contemplated herein to include " 10 μιη," as well as values understood in the art to be approximately 10 μιη with respect to the entity described. a) Impact Resistant, Opacity-Changing Laminate Devices

[0034] FIG. 1 shows an impact resistant, opacity-changing laminate device 100

according to an embodiment of the present invention. In some embodiments, the impact resistant, opacity-changing laminate device 100 comprises a transparent impact resistant layer 101 and an optically active element 102. In some embodiments, optically active element 102 is disposed along an optical path relative to transparent impact resistant layer 101. In some embodiments, optically active element 102 is configured to change from a first optical state to a second optical state more opaque than the first optical state in response to a projectile or other object incident on transparent impact resistant layer 101. The projectile includes, but not limited to, a stone, a bullet fired from a weapon, or high pressure water gun/stream. The other object includes, but not limited to, high powered laser, sonic weapon, or any other devices that are penetrating, damaging, and/or dangerous but are not projectiles. In some embodiments, optically active element 102 is configured to gradually change from a first optical state to a second optical state in response to user input. In some embodiments, the first optical state is transparent. In some embodiments, the second optical state is opaque. Alternatively in other

embodiments, the first optical state can be opaque and the second state can be transparent as desired.

[0035] In some embodiments, the first optical state and the second optical state can be user configurable or adjustable. For example, a user can control the first optical state and the second optical state through an interface. In some embodiments, the interface can connect to the optically active element through a wired connection or a wireless connection. In a non-limiting example, the wireless connection can be achieved via a Bluetooth connection or a WiFi connection. In some embodiments, the interface can be a visual interface. For example, the visual interface can be on-screen display on a smartphone, tablet, or personal computer (PC). In a non-limiting example, a user can control the first optical state and the second state of the optically active element through an on/off button, an up/down arrow, a left/right arrow, or a slider bar. In a non-limiting example, the slider bar can adjust the initial opacity between a minimum (transparent) and a maximum (opaque), or vice versa. In further embodiments, the user can configure or adjust the first optical state and the second optical state as desired.

[0036] In some embodiments, the transparent impact resistant layer 101 comprises one of more of the following materials: woven acrylic fiber, transparent ceramic fiber, polycarbonate, alumimum oxynitride, or combinations thereof. In some embodiments, the transparent impact resistant layer is ballistic impact resistant.

[0037] In some embodiments, optically active element 102 comprises two electrically conductive layers 103, 105 separated by one or more layers of electro-optic material 104 that change one or more of their optical properties in response to an electric field or current applied through the two electrically conductive layers 103, 105.

[0038] A voltage source 106 is shown to indicate a potential can be applied between conductive layers 103 and 105. Any type of fixed or variable voltage source can be used depending upon a particular application.

[0039] In a further embodiment, a piezoelectric material acting as a strain sensor can be coupled to one of the conductive layers 103, 105 to generate a voltage or current when strained by an incident projectile. In this way, laminate device 100 with a piezoelectric element operating as strain sensor need not have a voltage source 106 or can be used in combination with a voltage source 106.

[0040] In alternative configurations, a fixed or variable current source can be used

instead of voltage source 106.

[0041] In some embodiments, the laminate device further includes a distributed,

transparent impact sensor. In some embodiments, the distributed, transparent impact sensor include a transparent conductor film deposited on a substrate, a transparent piezoelectric polymer layer, sandwiched between a pair of transparent electrodes. The transparent piezoelectric polymer layer includes, but not limited to, poly(vinylidene fluoride) (PVDF). PVDF is one example of transparent piezoelectric polymer that builds a charge under impact or pressure. In some embodiments, the laminate device further includes a discrete impact sensor. The discrete impact sensor includes, but not limited to, those described in US Patent No. 5,917,410, which is incorporated herein by reference.

[0042] Optically active element 102 includes an electro-optic layer 104 that has one or more optical properties that change in response to an applied electric field or current applied at conductor layers 103, 105. The optical properties that change in response to an applied electric field or current include, but are not limited to, transparency, polarization or wavelength transmissivity.

[0043] In some embodiments, electro-optic layer 104 comprises one or more of the

following materials: electrochromic material, electroluminescent material, photochromic material, thermochromic material, polymer-dispersed liquid crystal (PDLC), or suspended particle device (SPD) material.

[0044] In some embodiments, the two electrically conductive layers 103, 105 comprise one or more of the following materials: indium tin oxide (ITO), tin oxide, zinc oxide, conductive polymers, graphene, carbon nanotubes, metallic grids, copper nanowires, silver nanowires, or combinations thereof.

[0045] In some embodiments, impact resistant, opacity-changing laminate device 100 include a protective cover 107. In some embodiments, protective cover 107 includes one or more layers that provide electrical insulation and scratch-resistance disposed over optically active element 102.

[0046] In some embodiments, impact resistant, opacity-changing laminate device 100 also has pane 108. In some embodiments, pane 108 is disposed before transparent impact resistant layer 101 and optically active element 102 along a same optical path from an external environment to an internal environment.

[0047] Examples of suitable panes 108 include, but not limited to, glass, ceramics, or polymers. In some embodiments, the polymers comprise acrylic polymers or

thermoplastic polymers. In some embodiments, the pane has two faces. In some embodiments, pane 108 comprises a windshield or window of a vehicle or building. Pane 108 is not so limited and any type of transparent substrate can be used.

[0048] In further embodiments, impact resistant, opacity-changing laminate device 100 can include one or more additional layers that provide anti-reflection, UV blocking, IR blocking, selective wavelength reflecting, light emission, information display, self- cleaning, breakage sensing or touch sensing functionalities.

[0049] FIG. 2 shows an impact resistant, opacity-changing laminate device 200 including layers 101, 103-105, 107 and 108 as described above, a controller 210 and a detector 220, according to another embodiment of the present invention. In some examples, controller 210 is coupled to voltage source 106 and configured to adjust the voltage level applied to the two electrically conductive layers 103 and 105 and control the optical state of optically active element 102.

[0050] In some embodiments, detector 220 detects when a projectile strains, impacts, or breaks at least one layer in the laminate device 200 and generates a signal representative thereof for output to controller 210. Controller 210 then adjusts the voltage level in response to the detected signal to change the optical properties of one or more layers of the electro-optic layer 104. Controller 210 can respond automatically in response to a signal from detector 220 or can respond in response to a user input. In different examples, a user can provide a user input to controller 210 through a switch, user-interface element, voice activation input or other type of input. Controller 210 can be a processor and memory, logic circuit or other type of controller, and can be implemented in hardware, firmware, software, or any combination thereof.

[0051] Impact resistant, opacity-changing laminate devices according to embodiments of the present invention offer significant advantages over traditional glass. In one non- limiting example, the cost to move heavy ballistic impact glass is significant due to the potential for breakage of unsecured glass panes, as well as the high weight of glass incurring high fuel costs. In one feature, a laminate device 100, 200 would allow for the use of locally-sourced, unstrengthened glass at a destination, and the simplified conversion of the local glass panes acting as a pane layer 108 to ballistic impact glass. This can be achieved simply by applying the remaining layers 101, 103-105, and optional cover 107 of laminate devices 100, 200 including to a surface of pane 108.

[0052] In a further feature not intended to be limiting, layers in laminate devices 100, 200 may have a density significantly less than glass and not nearly as fragile which reduces the cost of and breakage risk in shipping.

[0053] In a still further feature not intended to be limiting, laminate devices 100, 200 may control the opacity therethrough which obstructs a line of sight before or after a ballistic impact is registered against the strengthened glass pane.

[0054] In another feature, occupants of a building or vehicle may be able to escape, for instance in a fire, by breaking the laminated glass from the inside. Since the laminate device 100, 200 in examples may provide no additional strength to the glass panes 108 from an occupant-facing direction, escape is possible in this example, while it would not be possible by way of traditional impact glass, which does not confer unique unidirectional strengthening to glass panes.

[0055] Laminate devices 100, 200 according to embodiments also provide ways to impart additional benefits to conventional smart glass by way of introducing impact resistance. Moreover, in embodiments laminate devices 100, 200 may use new electrochromic (EC) materials as an alternative to PDLC-based systems. In these examples, the advantages of the use of EC materials include 1) increased resistance to UV degradation, 2) option for hundreds of colors of ECs in addition to the tinting options currently available for both the EC and electroluminescent (EL) materials, 3) lower power consumption requirements, 4) greater contrast between opacity and transparency including greater levels of opacity and/or transparency without the reduction of contrast against the opposing value.

Furthermore, in examples of a flexible laminate that is adhered to a glass pane 108 in laminate devices 100, 200 the possibility of glass fragments or shards injuring people is reduced in the unlikely event that ballistic penetration is achieved vs. the known shattering effect seen in traditional, unstrengthened glass panes as well as strengthened glass panes. b) Fabricating Impact Resistant, Opacity-Changing Laminate Devices

[0056] In a further embodiment, a method of fabricating an impact resistant, opacity- changing laminate device is provided. The method includes disposing a first electrically conductive layer on a transparent, impact resistant layer and disposing a second electrically conductive layer on a face of a protective cover. A further step includes arranging one or more layers of electro-optic material that change one or more of their optical properties in response to an electric field or current applied through the first and second electrically conductive layers.

[0057] In some embodiments, the method further comprises disposing on a substrate a face of a transparent, impact resistance layer opposite the first electrically conductive layer, whereby the substrate can be a pane on a windshield or window.

[0058] For example, referring to FIG. 1, the impact resistant, opacity-changing laminate device 100 can be fabricated by disposing the first electrically conductive layer 103 on the transparent, impact resistant layer 101, disposing the second electrically conductive layer 105 on a face of the protective cover 107, and arranging in between one or more layers of electro-optic material 10 that change one or more of their optical properties in response to an electric field or current 106 applied through the first and second electrically conductive layers 103 and 105. These disposing and arranging of the layers can be carried out using fabricating processes for laminates such as etching, printing, heating, rolling and bonding known to a person skilled in the art given this description. In addition, a face of the transparent, impact resistant layer 101 opposite the first electrically conductive layer 103 can be disposed on the substrate 108. In some embodiments, the substrate can be a windshield or window and the layers of the laminate devices 100, 200 can be pressed, rolled or adhered to the windshield or window which serves as pane 108. c) Obscuring an Interior Environment

[0059] FIG. 3 is a flowchart a diagram of a method for obscuring an interior environment with a laminate device according to an embodiment of the present invention. For brevity, the method will be described with respect to laminate devices 100, 200 but is not intended to be limited to these examples.

[0060] Referring to FIG. 3, method 300 can include detecting when an incident projectile strains, impacts, or breaks at least one layer in a laminate device 100, 200 (step 310)) and generating a signal representative of the detected projectile impact (step 320). For example, step 310 can involve automatically detecting an impact with a detector 220 or manually by a user activating a switch or making another type of user input. Step 320 can involve generating a signal in response to the detector and/or user input for output to controller 220.

[0061] In step 330, an optically active element changes its capacity to be more opaque in response to the detected signal. This can include adjusting (e.g., through a controller 210 in FIG. 2) a voltage level or electric current in response to the detected signal to change the optically active element from a first optical state to a second optical state more opaque than the first state. A laminate device 100, 200 can be arranged so a protective cover 107 faces an exterior environment and a pane 108 faces an interior environment (such as an interior of a vehicle or building) having one or more users. In this way, if a projectile or other object is incident on laminate devices 100, 200, changing the optical state to be more opaque can obscure the interior environment making it harder or impossible for anyone external to see the interior or continue a line of sight into the interior environment. In a non-limiting example, a building has a plurality of panes that are furnished with laminate devices 100, 200. If a projectile or other object is incident on one or more laminate devices, the user can configure or adjust the optical state to be opaque for all other laminate devices using a wireless signal.

CONCLUSION

[0062] These examples illustrate possible embodiments of the present invention. While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

The Summary and Abstract sections can set forth one or more, but not all exemplary embodiments of the present invention as contemplated by the inventor(s), and thus, are not intended to limit the present invention and the appended claims in any way.