PATENT DOCUMENT

Publication Number: US-10347443-B1
Application Number: US-201715605390-A
Country: US
Kind Code: B1

Title: Illuminated keyboard structures

Abstract:
Embodiments are directed to a backlight integrated membrane for a keyboard. In one aspect, an embodiment includes a keyboard having a key cap. A feature plate may be positioned below the key cap and a membrane may be positioned below the feature plate. The membrane may include a transparent substrate optically coupled to a light emitting element. The membrane may also include electrical traces for a key switch disposed on the transparent substrate. The embodiment may further include a domed structure positioned on the membrane and configured to actuate the key switch when depressed.

Claims:
What is claimed is: 
     
       1. A key for a keyboard, comprising:
 a key cap; 
 a feature plate positioned below the key cap; 
 a backlight integrated membrane positioned below the feature plate and comprising:
 a light emitting element; 
 a transparent substrate optically coupled to the light emitting element; and 
 electrical traces disposed on the transparent substrate; 
 
 a first terminal and second terminal on the transparent substrate and electrically connected to the electrical traces; 
 a domed structure positioned on the backlight integrated membrane above the first terminal and second terminal, the domed structure configured to collapse and thereby electrically connect the first terminal and second terminal; 
 a switch housing positioned below the keycap and having an opening positioned peripherally around the domed structure; and 
 a collar disposed about a periphery of the domed structure and abutting the opening of the feature plate, the collar resisting deformation of a portion of the domed structure upon its collapse. 
 
     
     
       2. The key of  claim 1 , wherein:
 the key cap is positioned within an opening of an enclosure and at least partially protrudes from the enclosure; 
 the key cap includes an illuminable surface; 
 the backlight integrated membrane directs light to the illuminable surface from the light emitting element; 
 the key further comprises a support structure positioned below the key cap; 
 the feature plate includes a set of engagement features; and 
 the support structure is coupled to the set of engagement features and an underside of the key cap. 
 
     
     
       3. The key of  claim 1 , wherein:
 the domed structure comprises a transparent material positioned above the transparent substrate and below the key cap. 
 
     
     
       4. The key of  claim 3 , wherein the light emitting element is positioned beneath the domed structure and is at least partially surrounded by the transparent substrate. 
     
     
       5. The key of  claim 1 , wherein:
 the feature plate defines a hole; and 
 the domed structure extends through the hole. 
 
     
     
       6. The key of  claim 5 , wherein a periphery of the domed structure is separated from the feature plate by the collar. 
     
     
       7. The key of  claim 6 , wherein a thickness of the collar is approximately equal to a thickness of the feature plate. 
     
     
       8. The key of  claim 1 , wherein:
 the backlight integrated membrane defines a vent positioned under the domed structure; and 
 the vent is in fluid communication with an interior volume of the domed structure. 
 
     
     
       9. The key of  claim 1 , further comprising a thermal bonding film directly adhered to the feature plate and the backlight integrated membrane. 
     
     
       10. The key of  claim 1 , further comprising a reflective component directly adhered to a bottom surface of the backlight integrated membrane. 
     
     
       11. An input mechanism, comprising:
 an input surface operative to receive an input; 
 a domed structure operative to collapse in response to the input; 
 a switch housing overmolded over at least part of the domed structure, at least a portion of the switch housing being transparent, the input surface being movable relative to the switch housing; 
 a transparent substrate positioned under the switch housing; 
 electrical traces on the transparent substrate, the electrical traces operative to transmit a signal generated by the domed structure; and 
 a light emitting element optically coupled to the transparent substrate; wherein 
 the transparent substrate redirects light from the light emitting element to the input surface. 
 
     
     
       12. The input mechanism of  claim 11 , wherein the input surface is a key cap of a keyboard key. 
     
     
       13. The input mechanism of  claim 11 , wherein the transparent substrate propagates light received from the light emitting element to an illuminable portion of the input surface. 
     
     
       14. The input mechanism of  claim 13 , wherein:
 the switch housing includes light extraction features that receive light from at least one of:
 the transparent substrate; or 
 the light emitting element; and 
 
 the switch housing illuminates the illuminable portion of the input surface using light received from the light extraction features. 
 
     
     
       15. The input mechanism of  claim 11 , wherein:
 an upper portion of the domed structure deforms in response to an input force exerted on the input surface; 
 a periphery of the domed structure defines a collar; and 
 the collar resists deformation of the upper portion once the upper portion impacts the collar. 
 
     
     
       16. The input mechanism of  claim 11 , wherein:
 the electrical traces are connected upon a first deformation of the domed structure; and 
 the input mechanism further comprises a sensing element that detects a second deformation of the domed structure. 
 
     
     
       17. An input structure for an electronic device, comprising:
 a light emitting element; 
 a backlight integrated membrane comprising a layer at least partially surrounding the light emitting element; 
 terminals on the backlight integrated membrane; 
 a housing structure on the backlight integrated membrane; 
 a domed structure positioned on the backlight integrated membrane at least partially within the housing structure and about the terminals; and 
 a key cap positioned above the domed structure and having an illuminable portion, wherein:
 the layer defines a light guide that directs light through the domed structure and toward the illuminable portion of the key cap; and 
 a vent extending through the layer and positioned below the domed structure. 
 
 
     
     
       18. The input structure of  claim 17 , wherein:
 the backlight integrated membrane further comprises an optical filler positioned between the light emitting element and the light guide; and 
 the optical filler optically couples the light emitting element and the light guide. 
 
     
     
       19. The input structure of  claim 17 , wherein:
 the housing structure defines light extraction features optically coupled with the light guide; and 
 the light guide directs light toward the illuminable portion of the key cap through the light extraction features. 
 
     
     
       20. The input structure of  claim 17 , wherein:
 the input structure further comprises:
 a feature plate; and 
 a scissor mechanism pivotally coupled with the feature plate and the key cap; and 
 
 the domed structure is overmolded over one of:
 the feature plate; or 
 the scissor mechanism.

Description:
FIELD 
     The described embodiments relate generally to input devices for computing systems. More particularly, the present embodiments relate to structures that facilitate illumination of a keyboard. 
     BACKGROUND 
     In computing systems, a keyboard may be employed to receive input from a user. Many traditional keyboards may suffer from significant drawbacks that may affect the visibility of keyboard keys in a dimly-lit environment. In many cases, traditional keyboards include various mechanical and electrical components that may impede illumination of the keyboard. 
     SUMMARY 
     Embodiments of the present invention are directed to a backlight integrated membrane circuit for a keyboard. 
     In a first aspect, the present disclosure includes a key for a keyboard. The key includes a keycap. The key further includes a feature plate positioned below the keycap. The key further includes a membrane positioned below the feature plate. The membrane includes a transparent substrate optically coupled to a light emitting element. The membrane further includes electrical traces for a key switch disposed on the transparent substrate. The key further includes a domed structure positioned on the membrane and configured to actuate the key switch when depressed. 
     A number of feature refinements and additional features are applicable in the first aspect and contemplated in light of the present disclosure. These feature refinements and additional features may be used individually or in any combination. As such, each of the following features that will be discussed may be, but are not required to be, used with any other feature combination of the first aspect. 
     For example, in an embodiment, the transparent substrate defines a light guide configured to receive light from the light emitting element. The transparent substrate may be further configured to emit light received from the light emitting element toward an illuminable portion of the key cap. In some cases, the domed structure may include a transparent material. The domed structure may be configured to receive light from the transparent substrate. Subsequently, the domed structure may be further configured to emit light received from the transparent substrate toward the illuminable portion of the key cap. This may cause the illuminable portion of the key cap to illuminate. 
     In another embodiment, the key may further include a support structure positioned below the key cap. The feature plate may include a set of engagement features. In this regard, the support structure may be coupled to the set of engagement features and an underside of the key cap to provide support to the key cap. Additional or alternatively, the feature plate includes a hole. The domed structure may extend through the hole. In some cases, the periphery of the domed structure may be positioned within the hole. Additionally or alternatively, a thickness of the periphery of the domed structure may be greater than a thickness of the feature plate. 
     In another embodiment, the light emitting element may be positioned on a lateral surface of the transparent substrate. The membrane may include a through portion positioned under the domed structure. The through portion may be configured to vent an interior volume of the domed structure. In some cases, a thermal bonding film is directly adhered to the feature plate and the membrane. 
     In this regard, a second aspect of the present disclosure includes a key for a keyboard. The key includes a key cap. The key includes a dome integrated switch housing positioned below the key cap. The dome integrated switch housing includes a domed structure. The dome integrated switch housing further includes a switch housing overmolded over a periphery of the domed structure. The key further includes a backlight integrated membrane positioned under the dome integrated switch housing. The backlight integrated membrane includes a circuit layer having light conductive properties. 
     A number of feature refinements and additional features are applicable in the second aspect and contemplated in light of the present disclosure. These feature refinements and additional features may be used individually or in any combination. As such, each of the following features that will be discussed may be, but are not required to be, used with any other feature combination of the second aspect. 
     For example, in an embodiment, the backlight integrated membrane further includes a light emitting element optically coupled with the circuit layer. The backlight integrated membrane may be configured to propagate light received from the light emitting element to an illuminable portion of the key cap. To facilitate the foregoing, in some cases, the dome integrated switch housing includes light extraction features that receive light from at least one of: (i) the backlight integrated membrane; or (ii) the light emitting element. As such, the dome integrated switch housing may be configured to illuminate an illuminable portion of the key cap using light received at the light extraction feature. The key may further include a reflector directly adhered to a bottom surface of the backlight integrated membrane. 
     In another embodiment, an upper portion of the domed structure may be configured to deform in response to an input force exerted on the key cap. The periphery of the domed structure may define a collar. The collar may be configured to resist deformation of the upper portion once the upper portion impacts the collar. The electrical traces may be configured to detect a first deformation of the rubber dome. In this regard, the key may further include a sensing element configured to detect a second deformation of the domed structure. 
     In another embodiment, the overmolded switch housing may have a hardness that is greater than a hardness of the domed structure. In some cases, the switch housing may define a securement feature that engages the backlight integrated membrane. 
     In this regard, a third aspect of the present disclosure includes an input structure for an electronic device. The input structure includes a membrane assembly defining a key switch for a keyboard key. The membrane assembly includes a light emitting element. The membrane assembly further includes a pair of layers at least partially surrounding the light emitting element and having electrical traces connected to the key switch. The input structure further includes a collapsible dome positioned on the membrane assembly. The input structure further includes a key cap positioned above the collapsible dome and having an illuminable portion. One of the pair of layers defines a light guide configured to direct light toward the illuminable portion of the key cap. 
     A number of feature refinements and additional features are applicable in the third aspect and contemplated in light of the present disclosure. These feature refinements and additional features may be used individually or in any combination. As such, each of the following features that will be discussed may be, but are not required to be, used with any other feature combination of the third aspect. 
     For example, in an embodiment, the membrane assembly may further include an optical adhesive positioned between the light emitting element and the light guide. The optical adhesive may be configured to couple the light emitting element and the light guide. The input structure may further include a switch housing overmolded over a portion of the collapsible dome and defining a series of illumination features configured to optically couple with the light guide. The light guide may direct light toward the illuminable portion of the input structure using the illumination features. 
     In another embodiment, the input structure may further include a feature plate and a scissor mechanism pivotally coupled with the feature plate and the key cap. In this regard, the collapsible dome may be overmolded over one of: (i) the feature plate; or (ii) the scissor mechanism. 
     In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like elements. 
         FIG. 1A  depicts a sample electronic device including a keyboard; 
         FIG. 1B  depicts a cross-sectional view of the embodiment of the user input device of  FIG. 1A , taken along line A-A of  FIG. 1A ; 
         FIG. 1C  depicts an enlarged view of a backlight integrated membrane of the user input device of  FIG. 1B ; 
         FIG. 1D  depicts a cross-sectional view of another embodiment of a backlight integrated membrane of the user input device of  FIG. 1A , taken along line A-A of  FIG. 1A ; 
         FIG. 2A  depicts an exploded view of a keyboard assembly of the keyboard of  FIG. 1A ; 
         FIG. 2B  depicts a cross-sectional view of the keyboard assembly of  FIG. 2A , taken along line B-B of  FIG. 2A ; 
         FIG. 3  depicts an exploded view of a keyboard assembly of the keyboard of  FIG. 1A  having an overmolded domed structure; 
         FIG. 4  depicts an exploded view of a keyboard assembly of the keyboard of  FIG. 1A  having an overmolded domed structure, according to another embodiment; 
         FIG. 5A  depicts an exploded view of another embodiment of a keyboard assembly of the keyboard of  FIG. 1A ; 
         FIG. 5B  depicts an enlarged view of a dome integrated switch housing of the keyboard assembly of  FIG. 4A ; 
         FIG. 5C  depicts a cross-sectional view of the keyboard assembly of  FIG. 5A , taken along line C-C of  FIG. 5A ; 
         FIG. 5D  depicts a cross-sectional view of another embodiment of the keyboard assembly of  FIG. 5A , taken along line C-C of  FIG. 5A ; and 
         FIG. 5E  depicts a cross-sectional view of another embodiment of the keyboard assembly of  FIG. 5A , taken along line C-C of  FIG. 5A . 
     
    
    
     The use of cross-hatching or shading in the accompanying figures is generally provided to clarify the boundaries between adjacent elements and also to facilitate legibility of the figures. Accordingly, neither the presence nor the absence of cross-hatching or shading conveys or indicates any preference or requirement for particular materials, material properties, element proportions, element dimensions, commonalities of similarly illustrated elements, or any other characteristic, attribute, or property for any element illustrated in the accompanying figures. 
     Additionally, it should be understood that the proportions and dimensions (either relative or absolute) of the various features and elements (and collections and groupings thereof) and the boundaries, separations, and positional relationships presented therebetween, are provided in the accompanying figures merely to facilitate an understanding of the various embodiments described herein and, accordingly, may not necessarily be presented or illustrated to scale, and are not intended to indicate any preference or requirement for an illustrated embodiment to the exclusion of embodiments described with reference thereto. 
     DETAILED DESCRIPTION 
     The description that follows includes sample systems, methods, and apparatuses that embody various elements of the present disclosure. However, it should be understood that the described disclosure may be practiced in a variety of forms in addition to those described herein. 
     The present disclosure describes systems, devices, and techniques related to a keyboard assembly or other input mechanism and, more particularly, to various illumination structures that illuminate one or more keys of a keyboard (or input surfaces of another input mechanism). An illumination structure may include a backlight integrated membrane, or other transparent, or partially transparent, portion of the keyboard assembly stack-up that includes electrical traces of a key switch. A light emitting element, such as a light emitting diode, may be positioned on, within, partially surrounded by, and/or be a portion of, the backlight integrated membrane, although in some embodiments the light emitting element may be separate from the backlight integrated membrane. The backlight integrated membrane may define a transparent substrate or light guide that directs light from the light emitting element to an illuminable portion of a keyboard key or other input surface. In some cases, the transparent substrate may at least partially surround the light emitting element. This may allow the backlight integrated membrane to be configured to both transmit a signal in response to actuation of the keyboard key (via the electrical traces of the key switch) and illuminate an illuminable portion of the key. For example, when the domed structure collapses, it may form an electrical connection between parts of the electrical traces, thereby generating an input signal. The electrical traces may transmit this signal to a processing unit or other element of an electronic device, thereby registering an input force as an input to the electronic device. 
     As used herein, the phrase “illuminable portion of a key” refers generally to any or all areas of (or adjacent to) a keycap or other input surface of a key that is intended to be illuminated by the light emitting element such that the location, size, and/or functionality of the key, or portion of the key, is visually emphasized. For example, a key may include a symbol or a glyph that defines an alphanumeric character, a punctuation mark, a word, an abbreviation, or any other linguistic, scientific, numeric, or pictographic symbol or set of symbols. The geometry of the key may also be an illuminable portion of the key, for example, such as a surface of the key defining a perimeter, a sidewall, a corner, and so on. 
     To facilitate the foregoing, light emitting element may be connected to, and/or partially surrounded by, the transparent substrate (e.g., light guide) of the backlight integrated membrane. Further, the transparent and/or internally reflective substrate may define signal-transmitting electrical traces, or these traces may be positioned on a surface of the substrate. The electrical traces may generate an input signal when connected. By integrating the light emitting element with the transparent substrate as described herein, the overall size and/or thickness of the stack-up for the keyboard assembly, or other input mechanism, may be reduced. Further, this may allow a surface area of the backlight integrated membrane to be increased, which may enhance the ability to route electrical traces and switch circuitry (such as a key switch) in or over the backlight integrated membrane. For example, because the backlight integrated membrane defines the light guide, the backlight integrated membrane may lack various holes and openings that would otherwise be used to allow light to pass through the backlight integrated membrane. The backlight integrated membrane may be implemented, secured, and/or installed in a variety of positions and configurations within the stack-up (e.g., below the feature plate, contacting a switch housing, or the like, as described herein), which may further reduce the stack-up size and/or enhance the versatility of the backlight integrated membrane within the stack-up. 
     To illustrate, in an embodiment, the backlight integrated membrane may be positioned within the keyboard stack-up below a feature plate. For example, the backlight integrated membrane may be directly adhered to a bottom surface of the feature plate via a thermal bonding film. The feature plate may be a structural portion of the stack-up that defines various engagement features at which a support structure of the key cap (e.g., a scissor mechanism, a butterfly mechanism, or the like) may be attached. A tactile or collapsible dome, such as a rubber, elastomeric, or otherwise deformable dome, may be positioned directly on a surface of the backlight integrated membrane and extend through a hole or opening of the feature plate and towards the key cap. By attaching the backlight integrated membrane to the bottom or lower surface of the feature plate, the overall height or thickness of the keyboard (or other suitable input mechanism) may be reduced. In particular, a portion of the height of the dome may overlap with the thickness or height of the feature plate, which may reduce the overall thickness of the keyboard stack. 
     Furthermore, by combining the light transmitting layer with the electrical conductive layer that forms part of the keyboard/input switch, the overall height of the keyboard stack/input mechanism may be further reduced. The light-transmitting layer may be used to deliver light to each key assembly, which may transmit the light to the underside of the key cap. In one embodiment, the backlight integrated membrane may aid in lighting the illuminable portion of the key via the domed structure, which may be constructed from a fully or partially transparent material. Thus, light may pass from the light emitting element, to the transparent substrate (which may least partially surround the light emitting element), through the transparent material of the domed structure above the membrane, and to an illuminable portion of a key cap positioned above the domed structure. In other cases, other components of the stack-up, positioned above or extending through the feature plate, may be used with the backlight integrated membrane to light an illuminable portion of the key or key cap. 
     In another embodiment, the backlight integrated membrane may be directly coupled with a dome integrated switch housing that may direct light to the illuminable portion of the key or key cap. In particular, the backlight integrated membrane may be coupled with an overmolded switch housing that is overmolded over a tactile or collapsible dome. The overmolded switch housing and domed structure may collectively define the dome integrated switch housing, which may form a structural component of the stack-up that is also used to detect actuation of the key or key cap. The overmolded switch housing and/or domed structure may include various light extraction features and/or other illumination features that receive light from the backlight integrated membrane, which may be subsequently directed to the illuminable portion of the key or key cap. 
     As described herein, the dome integrated switch housing may include or define various features that may decrease stress and strain on the domed structure over time. For example, a collar, reinforcement member, or other structure integrally formed with the switch housing or domed structure may extend around a perimeter of the domed structure and impede or resist deformation of various portions of the domed structure. Additionally or alternatively, the overmolded switch housing and/or domed structure may include various sensing elements that augment or support the electrical traces connected to the key switch defined within the backlight integrated membrane. For example, a sensing element (e.g., a capacitive-based sensor, a contact-based sensor, or any other appropriate sensor) may be coupled to, or defined by, a portion of the overmolded switch housing and/or the domed structure and configured to detect a range of deformations of the domed structure. The electrical traces may transmit an input signal to a processing unit or other element of an electronic device in response to the sensing element detecting deformation (or collapse) of the domed structure. That is, the deformation of the dome may connect the electrical traces by closing the key switch, thereby generating and/or providing a signal path for an input signal. 
     It will be appreciated that the backlight integrated membrane may be constructed, configured, and/or arranged in a variety of manners, as described herein. In some cases, the backlight integrated membrane may be a single transparent substrate optically coupled with a light emitting element, or even partially surrounding the light emitting element. In other cases, the backlight integrated membrane may include two, three, or more layers as may be appropriate for a given application. In still other embodiments, the backlight integrated membrane may include the transparent substrate formed by one or more layers and an integrated, or partially or fully surrounded, light emitting element. In a particular embodiment, the backlight integrated membrane may include a pair of sensing layers at least partially surrounding a light source and having electrical traces of a key switch positioned on each layer. One or more of the layers may define a light guide, formed as a transparent substrate, which is configured to direct light toward the illuminable portion of the key. The light emitting element may be optically coupled to the one or more layers of the backlight integrated membrane using any appropriate techniques, including via an optical filler that bonds the light emitting element to a given layer or portion of the transparent substrate. In some cases, the optical filler may reduce undesirable light reflection and refraction within the backlight integrated membrane. 
     It should be appreciated that certain embodiments may take the form of an input structure other than a key of a keyboard. For example, a mouse button, trackpad, standalone button, or the like may all incorporate embodiments disclosed herein. Thus, as one non-limiting example, an input button may replace a key in some embodiments, just as an input surface of such a button may replace a key cap. 
     Reference will now be made to the accompanying drawings, which assist in illustrating various features of the present disclosure. The following description is presented for purposes of illustration and description. Furthermore, the description is not intended to limit the inventive aspects to the forms disclosed herein. Consequently, variations and modifications commensurate with the following teachings, and skill and knowledge of the relevant art, are within the scope of the present inventive aspects. 
       FIG. 1A  depicts an example electronic device  104  having a keyboard assembly  108 , although other input mechanisms may incorporate embodiments discussed herein. Each key of the keyboard assembly  108  may include a “stack-up” of layer components that cooperate to initiate an input signal in response to a force input. The keyboard assembly  108  may include one or more backlight integrated membranes, such as the backlight integrated membrane as discussed above and described in greater detail below. As described herein, the backlight integrated membrane may be configured to detect actuation of a keyboard key (e.g., via electrical traces, terminals, tabs, and/or other elements that may function as, or with, a key switch and that are positioned on or within the backlight integrated membrane) and aid in lighting an illuminable portion of the keyboard key. 
     In a non-limiting example, as shown in  FIG. 1A , the electronic device  104  may be a laptop computer. However, it is understood that electronic device  104  may be any suitable device that operates with the keyboard assembly  108  (or any other suitable device or input mechanism configured to receive a touch and/or force input from a user). Some example electronic devices may include data-entry devices, word-processing devices, desktop computers, notebook computers (as shown in  FIG. 1A ), smart phones, tablets, portable media players, or the like. Other examples of electronic devices may include health monitoring devices (including pedometers, heart rate monitors, or the like), and other electronic devices, including digital cameras, printers, scanners, security systems or devices, or electronics for automobiles, among other electronic devices. Suitable input mechanisms may include trackpads, mice, joystick, buttons, and so on. 
     For purposes of illustration,  FIG. 1A  depicts the electronic device  104  as including the keyboard assembly  108 , an enclosure  112 , a display  116 , and one or more input/output members  120 . It should be noted that the electronic device  104  may also include various other components, such as one or more ports (e.g., a charging port, a data transfer port, or the like), communications elements, additional input/output members (including buttons), and so on. As such, the discussion of any computing device, such as the electronic device  104 , is meant as illustrative only. 
     The keyboard assembly  108  may be positioned within the electronic device  104 . In a non-limiting example shown in  FIG. 1A , the keyboard assembly  108  may include a set of illuminable keys  110 . Each of the set of illuminable keys  110  may have an illuminable portion, as described above, at which light from a light emitting element may visually emphasize a location, size, and/or functionality of the key. The set of illuminable keys  110  may be substantially surrounded by, and at least partially protrude from, the enclosure  112 . The set of illuminable keys  110  may be configured to receive a force input. The force input may depress a particular one of the set of illuminable keys  110  to trigger one or more input signals that may control the electronic device  104 . As depicted, the keyboard assembly  108  may be positioned within the electronic device  104 . In other embodiments, the keyboard assembly  108  may be a distinct, standalone component communicatively coupled with the electronic device  104  via a wireless or hardwired connection. 
       FIG. 1B  is a cross-sectional view of the keyboard assembly  108  of  FIG. 1A , taken along line A-A of  FIG. 1A . As illustrated, the keyboard assembly  108  includes a key cap  124  (e.g., such as one of the set of illuminable keys  110  discussed above), a domed structure  128 , and a backlight integrated membrane  132 . The key cap  124  may define an input surface of the keyboard assembly  108  and is similar to other possible input surfaces such as mouse buttons, trackpads, joystick buttons, standalone buttons, and so on. For example, the key cap  124  may be configured to receive a force input to actuate one or more switches of the keyboard assembly  108 . The key cap  124  may include an illuminable portion (e.g., glyph, symbol, sign and/or geometric features, including surfaces, perimeters, sidewalls, corners, and so on) that is intended or configured to be illuminated by a light emitting element of the keyboard assembly  108 . As shown in  FIG. 1B , the key cap  124  includes an illuminable surface  126 . 
     The key cap  124 , or other input surface, may be positioned over the domed structure  128 . The domed structure  128  may be any appropriate collapsible dome or elastically deformable structure configured to buckle in response to an applied force. For example, the domed structure  128  may be formed from any sufficiently elastic and resilient material (e.g., rubber, silicone, metal, or the like) such that it does not necessarily permanently deform in response to an applied force resulting from motion of the key cap  124  in response to an input. Put another way, the domed structure  128  may substantially return to an original or undeformed shape after an input ceases. In this regard, the key cap  124  may deform the domed structure  128  in response to a user input, such as a force, received at the key cap  124 . This deformation and/or collapse of the domed structure may electrically connect a set of terminals positioned on (or forming part of) the backlight integrated membrane, thereby generating an input signal. To facilitate the foregoing, a support structure, such as a scissor mechanism, butterfly mechanism, and so on may support the key cap  124  above the domed structure  128  and/or guide movements of the key cap  124  when the key cap  124  impacts the domed structure  128 . 
     The domed structure  128  may be positioned on the backlight integrated membrane  132 . The backlight integrated membrane  132  may be a sensing membrane that defines a keyboard membrane circuit or circuit layer used to detect an actuation of the key cap  124 . In this regard, the backlight integrated membrane  132  may include various electrical traces, such as electrical traces  151  shown in  FIG. 1B , that define a circuit layer and which may be used to transmit an input signal caused by a depression or collapse of the domed structure  128  in response to force exerted on the key cap. For example, the domed structure  128  may include a conductive bottom surface that completes a circuit between terminals on the backlight integrated membrane. The backlight integrated membrane  132  may also be a substantially transparent component that guides or directs light through the keyboard assembly  108  (e.g., to the domed structure  128 , the key cap  124 , and so on), for example to an illuminable surface of the key cap. Accordingly, the backlight integrated membrane  132  may: 1) include a circuit layer having light conductive properties that both generates an input signal in response to collapse of the domed structure  128  due to force exerted on the key cap  124 ; and 2) aid in providing light to illuminable portions of the key cap  124 . 
     In the embodiment of  FIG. 1B , the backlight integrated membrane  132  may be or include a transparent substrate  134 . The transparent substrate  134  may be constructed from any appropriate material that allows light to propagate or pass through a thickness, length, or other dimension of the material. Sample materials include polyethylene terephthalate (PET), acrylic, silicone, or the like. In other cases, other materials are contemplated, including embodiments in which a combination of materials may be used to construct the transparent substrate  134 . The transparent substrate  134  may also include various optical properties that allow the transparent substrate  134  to direct light toward various portions of the keyboard assembly  108  (e.g., such as toward an illuminable portion of the key cap  124 ). Electrical traces and/or one or more light sources may be attached to, or integrated within, the transparent substrate  134  to form the backlight integrated membrane  132 . 
     As shown in  FIG. 1B , the backlight integrated membrane  132  includes terminals  150   a ,  150   b . As shown, the terminals  150   a ,  150   b  as deposited on, or form part of, a surface of the transparent substrate  134 . In other cases, the terminals  150   a ,  150   b  may be positioned at least partially within the transparent substrate  134 . The terminals, taken together, form a key switch. The key switch terminals  150   a ,  150   b  may form part of a keyboard membrane circuit layer that is configured to detect actuation of the key cap  124 . For example, the terminals  150   a ,  150   b  may be electrically connected by an underside of the domed structure  12 , when the domed structure collapses. In this regard, the underside of the domed structure  128  may be a conductive surface that electrically connects the terminals  150   a ,  150   b  of the key switch when the dome collapses. In one embodiment, the collapsing dome may be used to generate an input signal by electrically connecting the terminals  150   a ,  150   b.    
     The terminals  150   a ,  150   b  may be electrically connected to the electrical traces  151 . In this regard, the terminals  150   a ,  150   b  may provide a key-specific electrical signal (e.g., input) to the electronic device  104 , transmitted through the electrical traces  151 , when the key cap  124  is actuated and the domed structure  128  collapses to electrically connect the terminals. It will be appreciated that in other embodiments, other combinations, orientations, and/or arrangements of terminals  150   a ,  150   b , or other electrical traces or sensors, are contemplated. 
     Generally, force exerted on the key cap  124  may cause the key cap to move toward the backlight integrated membrane  132 . The key cap&#39;s motion may fully or partially deform or collapse the domed structure  128 . This collapse may bridge or otherwise electrically connect the terminals  150   a ,  150   b , thereby generating a corresponding input signal. The input signal may be transmitted along the electrical traces  151  electrically connected to the terminals, for example. 
     The key switch terminals  150   a ,  150   b , electrically connected electrical traces  151 , and/or any other components or sensors of the backlight integrated membrane  132  may be constructed from any appropriate material configured to complete an electrical circuit. In some cases, the terminals  150   a ,  150   b  may be constructed from one or more of copper, carbon, and/or indium tin oxide, however, in other embodiments, other materials are contemplated. The terminals  150   a ,  150   b  may be formed on the transparent substrate  134  in various manners to produce the circuit layer of the backlight integrated membrane  132 . For example, the key switch terminals  150   a ,  150   b  may be arranged on the transparent substrate  134  via deposition, sputtering, printing, or other appropriate process. 
     The backlight integrated membrane  132  may also include, or be coupled with, a light emitting element  136 . The light emitting element  136  may be a light emitting diode (“LED”) or other appropriate component configured to emit light into the keyboard assembly  108 . Light emitted by the light emitting element  136  may be used by various components of the keyboard assembly  108  to light an illuminable portion of the key cap  124 . 
     As shown in  FIG. 1B , a transparent substrate of the backlight integrated membrane  132  includes and/or at least partially surrounds the light emitting element  136 . The light emitting element may be positioned within an interior volume of the transparent substrate  134 . This may allow light emitted from the light emitting element  136  to transmit or propagate into the transparent substrate  134 . Put another way, the backlight integrated membrane directs light from the light emitting element. In other cases, as described in greater detail below, the light emitting element  136  may be positioned and/or secured on an outer surface of one or more layers (e.g., transparent substrate  134 ) of backlight integrated membrane  132 . The light emitting element  136  may be directly attached to, or integrated within, the transparent substrate  134  using an optical adhesive, glue or other optically transparent interstitial layer that may bond the light emitting element  136  and the backlight integrated membrane  132  and so that the backlight integrated membrane may redirect light from the light emitting element to illuminate a key cap or other input surface. 
     The backlight integrated membrane  132  may be configured to propagate, transmit or otherwise direct light to an illuminable portion of the key cap  124 . For example, the transparent substrate  134  of the backlight integrated membrane  132  may be a structure that spans an entire dimension of the key cap  124  (or the entire dimension of the set of keys  110 ), or at least a portion of a key cap dimension. The transparent substrate  134  may thus receive light from the light emitting element  136  at a first location and transmit or propagate the received light to a second location with the keyboard assembly  108 . This may allow the backlight integrated membrane  132  to aid in providing light to illuminable portions of the key cap  124 . To illustrate, as shown in  FIG. 1 , the transparent substrate  134  may receive light from the light emitting element  136  along light path L 1 . The transparent substrate  134  may propagate light to a region of the keyboard assembly  108  positioned directly below the key cap  124  and/or the domed structure  128 , thereby causing an illuminable portion of the key cap  124  to illuminate. By way of particular example, the transparent substrate  134  of the membrane may emit light along light path L 2 , which may cause light from the light emitting element  136  to travel toward an underside surface  125  of the key cap  124  such that the illuminable surface  126  illuminates. Put another way, the backlight integrated membrane may direct light to illuminate the illuminable surface  126  of the key cap  124 . 
     Additionally or alternatively, the transparent substrate  134  may propagate light into and through the domed structure  128  along light path L 2 , which may also cause an illuminable portion of the key cap  124  to illuminate. For example, the domed structure  128  may be a transparent structure optically coupled with the transparent substrate  134 . In turn, the domed structure  128  may be configured to emit light along light path L 3 , which may cause light to travel through or across the underside surface  125  of the key cap  124  to illuminate the illuminable surface  126 . 
     It will be appreciated that the light paths L 1 , L 2 , L 3  are depicted for purposes of illustration only. Rather than suggest that the light travels exclusively along a particular light path, the illustrated light paths are depicted to be a representation of the diffuse light that propagates with the keyboard assembly  108 . 
       FIG. 1C  depicts detail  1 - 1  of the backlight integrated membrane  132  depicted in  FIG. 1A . As shown in the non-limiting example of  FIG. 1C , the backlight integrated membrane  132  may include an optical filler  139 . The optical filler  139  may be ultraviolet (UV) glue or another optical adhesive. The optical filler  139  may be used to optically couple (e.g., bond) the light emitting element  136  to the transparent substrate  134  and/or other components of the keyboard assembly  108 . For example, as shown in  FIG. 1C , the optical filler  139  may be positioned between the light emitting element  136  and the transparent substrate  134  to secure the light emitting element  136  to the transparent substrate  134  within the backlight integrated membrane  132 . 
     The optical filler  139  may also be used to optically couple the light emitting element  136  and the transparent substrate  134 . In particular, the optical filler  139  may be configured to reduce light reflection and refraction between the light emitting element  136  and the transparent substrate  134 . For example, the light emitting element  136  and the transparent substrate  134  may each exhibit different indices of refraction. As such, light transmitted between the light emitting element  136  and the transparent substrate  134  may tend to reflect and/or refract across a boundary or interface between the light emitting element  136  and the transparent substrate  134 . In this regard, the optical filler  139  may be positioned along an interface between the light emitting element  136  and the transparent substrate  134  to reduce such effects. For example, the optical filler  139  may have an index of refraction that is substantially between that of the transparent substrate and the light emitting element  136 . Accordingly, the change in the index of refraction experienced by the light may not be as abrupt. This may enhance the ability of the transparent substrate  134  to receive light from the light emitting element  136 . As shown in  FIG. 1C , the light emitting element  136  may emit light along light path L 1  that travels into the transparent substrate  134  without substantially experiencing undesirable reflection or refraction. 
       FIG. 1D  depicts a cross-sectional view of another embodiment of the keyboard assembly  108  of  FIG. 1A , taken along line A-A of  FIG. 1A . As illustrated,  FIG. 1D  depicts the key cap  124 , the domed structure  128 , and a backlight integrated membrane  232 . The backlight integrated membrane  232  includes a stack-up of multiple sheets, films, or the like that cooperate to define a keyboard membrane circuit layer that completes an electrical path upon an actuation of the key cap  124 , thereby generating an input signal for an electronic device. One or more of the multiple sheets may be a transparent component that may aid in providing light to an illuminable portion of the key cap  124 , such as illuminable surface  126 . Accordingly, substantially analogous to the backlight integrated membrane  132  described with respect to  FIG. 1B , the backlight integrated membrane  232 , described with respect to  FIG. 1D , may be a single integrated component that both detects actuation of the key cap  124  and aids in providing light to illuminable portions of the key cap  124 . In this regard, analogous to the components described in relation to the embodiments of  FIG. 1B , the backlight integrated membrane  232  may include terminals  250   a ,  250   b , electrical traces  251 , and light emitting element  236 . The terminals  250   a ,  250   b  may collectively form a key switch. 
     Notwithstanding the foregoing, the backlight integrated membrane  232  may include a transparent substrate that is defined by multiple, separated layers. For example, as illustrated in the embodiment of  FIG. 1D , the backlight integrated membrane  232  may include a top sheet  234   a  and a bottom sheet  234   b . One or both of the top sheet  234   a  and/or the bottom sheet  234   b  may be a substantially transparent component configured to transmit or propagate light. The top sheet  234   a  and the bottom sheet  234   b  may be separated by a membrane spacer  237 . The top sheet  234   a  and the bottom sheet  234   b  may be directly adhered or coupled with opposing surfaces of the membrane spacer  237 . The membrane spacer  237  may include hole  238 . The top sheet  234   a  and the bottom sheet  234   b  may be configured to deform or otherwise extend into the hole  238  (and toward one another) in response to an applied force (e.g., caused by an actuation of the key cap  124 ). 
     The terminal  250   a  may be positioned within, and form an external surface of, the top sheet  234   a . The terminal  250   b  may be positioned within, and form an external surface of, the bottom sheet  234   b . As shown in  FIG. 1D , the terminals  250   a ,  250   b  may be spaced apart from one another within the hole  238  when the backlight integrated membrane  232  is in an uncompressed state. Upon actuation of the key cap  124 , the top and bottom sheets  234   a ,  234   b  may deflect and cause the terminals  250   a ,  250   b  to move toward one another and close the key switch. This may complete an electrical connection that is used by the keyboard assembly  108  to generate an input signal. 
     In the embodiment of  FIG. 1D , the backlight integrated membrane  232  includes the light emitting element  236 . The light emitting element  236  may be arranged in any appropriate position or orientation within the backlight integrated membrane  232  such that the light emitting element  236  is optically coupled with one or both of the top sheet  234   a  or the bottom sheet  234   b . As such, one or both of the top sheet  234   a  or the bottom sheet  234   b  may be a substantially transparent component configured to guide or propagate light to aid in lighting an illuminable portion of the key cap  124 . In a particular configuration, as shown in  FIG. 1D , the light emitting element  236  may be positioned on a surface of the top sheet  234   a  and extend through the membrane spacer  237  and at least partially into a volume defined by the bottom sheet  234   b . It will be appreciated that other configurations are contemplated, including configurations in which the light emitting element  236  is positioned at least partially within a volume of the top sheet  234   a  and the bottom sheet  234   b.    
     As shown in  FIG. 1D , the light emitting element  236  may emit light into the keyboard assembly  108  to illuminate an illuminable portion of the key cap  124 , such as illuminable surface  126 . In particular, the light emitting element  236  may emit light into one or both of the top or bottom sheets  134   a ,  134   b , for example, substantially along light path L 1 . The top sheet  134   a  and/or the bottom sheet  134   b  may receive light from the light emitting element  236  and transfer or propagate the received light to another location or region of the keyboard assembly  108  to facilitate illuminating the key cap  124 . For example, as shown in  FIG. 1D , the top sheet  134   a  may emit light below the key cap  124  substantially along light path L 2 . In some cases, as described above with respect to  FIG. 1B , the domed structure  128  may be a transparent structure. In this regard, the domed structure  128  may receive light from the top sheet  234   a  and transmit the received light to the key cap  124 . For example, the domed structure  128  may emit light substantially along light path L 3 , which may extend through the underside surface  125  and into the key cap  124 . This may cause the illuminable surface  126  to illuminate. 
       FIGS. 2A-4  depict embodiments of the keyboard assembly  108  in which the backlight integrated membrane  132 , described herein, is positioned below a feature plate of the keyboard assembly  108  stack-up. This may reduce an overall size and/or thickness of the keyboard assembly  108 . The feature plate may include or define various holes, openings, or the like that may be configured to allow the backlight integrated membrane  132  to both light an illuminable portion of the key cap  124  and detect an actuation of the key cap  124 . 
       FIG. 2A  depicts an illustrative exploded view of an embodiment of the keyboard assembly  108  shown in  FIG. 1A . As described above, the keyboard assembly  108  may be formed from a stack-up of layered components. Each layer and/or component of the stack-up of the keyboard assembly  108  may provide different functionality and/or operations for the electronic device  104 , as discussed herein. Although a single key stack-up of keyboard assembly  108  is shown in  FIG. 2A , it is understood that substantially all keys (or a subset of keys) of the keyboard assembly  108  may be formed from similar components and/or layers in a similar configuration and/or function in a substantially similar manner as the single key stack-up shown in  FIG. 2A . 
     The keyboard assembly  108  may include the backlight integrated membrane  132 , such as the backlight integrated membrane  132  described with respect to  FIG. 1B . The backlight integrated membrane  132  may be positioned below a web (defined or formed from the enclosure  112 ) and the key cap  124 . The backlight integrated membrane  132  may be coupled to the web or other portion of the enclosure  112  using various components of stack-up forming the keyboard assembly  108 , as described herein. 
     As described with respect to  FIG. 1B , the backlight integrated membrane  132  may be defined by a transparent substrate directly attached and/or optically coupled with the light emitting element  136 . This may allow the backlight integrated membrane  132  to direct light to various portions of the keyboard assembly  108  to facilitate lighting an illuminable portion of the key cap  124 . The backlight integrated membrane  132  may include electrical traces  151 , terminals  150   a ,  150   b  (not shown in  FIG. 2A ), or the like formed therein or thereon; the traces and terminals may be electrically connected to one another. The traces may provide an electrical signal (e.g., input) to electronic device  104  when the domed structure  128  collapses or is otherwise deformed in response to a force exerted on the key cap  124 , as discussed herein. The backlight integrated membrane  132  may cover and/or include a geometry substantially equal to an area of the keyboard assembly  108  formed or positioned within the enclosure  112  of the electronic device  104 . 
     As shown in  FIG. 2A , the domed structure  128  may be coupled directly to the backlight integrated membrane  132 . The domed structure  128  may be laminated, adhered, or otherwise directly affixed to the backlight integrated membrane  132 . For example, the domed structure  128  may be positioned in or on a pressure sensitive adhesive, ultraviolet (UV) glue, or other adhesive deposited over a top surface of the backlight integrated membrane  132 . The adhesive may be cured to affix the domed structure  128  and the backlight integrated membrane  132 . In other cases, the domed structure  128  may be an overmolded component molded over one or more components of the backlight integrated membrane  132 . 
     In the embodiment of  FIG. 2A , the keyboard assembly  108  may include a feature plate  160 . The feature plate  160  may be a structural portion of the stack-up that defines various engagement features, to which a support structure of the keyboard assembly (e.g., a scissor mechanism, a butterfly mechanism, or the like) may be attached. The feature plate  160  may be constructed substantially from any suitable electrically conductive sheet metal including, but not limited to: aluminum, steel, stainless steel, metal alloys, and so on. Additionally or alternatively, other materials and constructions of the feature plate  160  are contemplated, including embodiments in which the feature plate  160  is constructed from an electrically insulating material, a ceramic, or the like. 
     In a particular implementation, the feature plate  160  may include a set of engagement features  162  that is configured to couple to a scissor mechanism  140  (or other analogous support structure of the keyboard assembly  108 ) that is positioned between the feature plate  160  and the key cap  124 . As one example, the support structure may be positioned above the feature plate and below the key cap, and engaged with both. The set of engagement features  162  may be tabs, protrusions, or other features extending from a surface of the feature plate  160 . In some cases, some or all of the set of engagement features  162  may have holes that are configured to receive, or otherwise couple to, a corresponding engagement structure of, for example, the scissor mechanism  140 . This may allow the scissor mechanism  140  to pivot relative to the feature plate  160 . 
     The scissor mechanism  140  may include an outer scissor member  142   a  and an inner scissor member  142   b  that pivot relative to one another during actuation of the key cap  124 . One or more of the set of engagement features  162  may be partially received by, or otherwise coupled to, the scissor mechanism  140  (e.g., one or both of the outer scissor member  142   a  or the inner scissor member  142   b ) and guide motion of the scissor mechanism  140  during actuation of the key cap  124 . 
     The feature plate  160  also includes a set of openings  163 . The set of openings  163  may extend completely through the feature plate  160 . The set of openings  163  may allow light to pass unobstructed through the feature plate  160 . Additionally, the set of openings  163  may be configured to receive one or more components of the keyboard assembly  108  (e.g., the domed structure  128 , coupling components, and so on), as described herein. 
     As shown in  FIG. 2A , the backlight integrated membrane  132  is positioned below the feature plate  160 . In one embodiment, the backlight integrated membrane  132  may be directly attached to the feature plate  160  via a thermal bonding film  164 . The thermal bonding film  164  may be defined by a geometry that is substantially analogous to the geometry of the feature plate  160 , including defining holes, openings, or other features corresponding to the set of holes  163  defined by the feature plate  160 . 
     As described above, the domed structure  128  may be positioned on or directly attached to the backlight integrated membrane  132 . In this regard, in an assembled configuration (as shown in  FIG. 2B ), the domed structure  128  may extend through the thermal bonding film  164  and the feature plate  160  (via one of the set of holes  163 ) and toward the key cap  124 . This may allow the domed structure  128  to receive a force from an actuation of the key cap  124 , notwithstanding the domed structure  128  being directly attached to the backlight integrated membrane  132 , which is positioned below the feature plate  160 . 
       FIG. 2B  depicts a cross-sectional view of the keyboard assembly  108  of  FIG. 2A , taken along line B-B of  FIG. 2A . Some of the layers or components of the keyboard assembly  108 , for example, the electrical traces  151 , have been omitted for clarity. The keyboard assembly  108  depicted in  FIG. 2B  is shown in an assembled configuration. As such, the domed structure  128  is shown positioned on a surface of the backlight integrated membrane  132  and extending through one of the set of openings  163  and toward the key cap  124 . 
     As shown in the assembled configuration of  FIG. 2B , the domed structure  128  may have a periphery  129  that is positioned within an opening  163  of the feature plate  160 . This may help support and/or stabilize the domed structure  128  within the keyboard assembly  108 . In some cases, the periphery  129  and the feature plate  160  may be separated by a gap or other offset. The periphery  129  of the domed structure  128  may have a thickness that is substantially equivalent to a thickness of the feature plate  160 . In other cases, the thickness of the periphery  129  may be smaller or larger than a thickness of the feature plate  160 , as may be appropriate for a given application. 
     As demonstrated in the assembled configuration of  FIG. 2B , the keyboard assembly  108  may have a reduced thickness due in part to the domed structure  128  extending through the opening  163  of the feature plate  160 . For example, a portion of the domed structure  128  may be nested within a thickness of the feature plate  160 . This nesting may help reduce the height of the keyboard. Further, the light guide and the circuit layer of the keyboard assembly  108  are contained within the backlight integrated membrane  132 , which further reduces thickness. 
     In the embodiment of  FIG. 2B , the backlight integrated membrane  132  includes a vent  138 . The vent  138  may be a through portion that completely extends through the backlight integrated membrane  132 . The vent  138  may be positioned within the backlight integrated membrane  132  below the domed structure  128 . In this regard, the vent  138  may provide a passage or channel between an enclosed region above the backlight integrated membrane  132  (enclosed by the domed structure  128 ) and a region or volume positioned below the backlight integrated membrane  132 , or may otherwise be in fluid communication with such a region or volume. Accordingly, when the domed structure  128  buckles, collapses, or otherwise deforms in response to an input force exerted on the key cap  124 , air enclosed by the domed structure  128  may be expelled through vent  138  and transmitted to another region of the keyboard assembly  108  (e.g., a region positioned below the backlight integrated membrane  132 ). Positioning the vent  138  directly below the domed structure  128  may also enhance waterproofing features of the keyboard assembly  108 . For example, the domed structure  128  and the backlight integrated membrane  132  may form a liquid and/or moisture resistant or impermeable barrier, while still allowing air enclosed below the domed structure  128  to pass through the vent  138  upon actuation of the key cap  124 . 
     As described herein, the backlight integrated membrane  132  may be used to aid in guiding light to an illuminable portion of the key cap  124 . As such, as depicted in  FIG. 2B , the backlight integrated membrane  132  may include the transparent substrate  134  and the light emitting element  136 . Light emitted by the light emitting element  136  may travel through the transparent substrate  134  to light an illuminable portion of the key cap  124 . For example, light emitted by the light emitting element  136  may propagate through the transparent substrate  134  and exit at or near one or more of the set of holes  163 . In some cases, this may directly illuminate an illuminable portion of the key cap  124  (e.g., such as illuminating a border, surface, corner, or the like of the key cap  124 ). In other cases, the backlight integrated membrane  132  may be configured to transmit light to the domed structure  128 , which may in turn cause an illuminable portion of the key cap  124  to illuminate. For example, the domed structure  128  may be fully or partly formed from a substantially transparent material that is configured to propagate light toward the key cap  124  to illuminate a glyph, symbol, sign, and/or other illuminable portion of the key cap  124 . To facilitate such light propagation, the transparent material of the domed structure may be positioned above the transparent membrane and below the key cap. 
       FIG. 3  depicts an illustrative exploded view of another embodiment of the keyboard assembly  108  in  FIG. 1A . In particular,  FIG. 3  depicts an exploded view of the keyboard assembly  108  in a configuration in which the domed structure  128  is directly coupled with the feature plate  160 . For example, the domed structure  128  may be an overmolded component that is molded over the feature plate  160 . To facilitate the foregoing, the domed structure  128  may be an injection moldable rubber, plastic, or other material that is formed over a surface of the feature plate  160 , which may be constructed from steel or other sheet metal material, as described above. This may enhance the manufacturability of the keyboard assembly  108 , for example, by decreasing the number of individual components that are used to build the stack-up. 
       FIG. 4  depicts an illustrative exploded view of another embodiment of the keyboard assembly  108  in  FIG. 1A . In particular,  FIG. 4  depicts an exploded view of the keyboard assembly  108  in a configuration in which the domed structure  128  is directly coupled with the inner scissor member  142   b . For example, the inner scissor member  142   b  may be formed from an injection-moldable material that is formed over the periphery  129  of the domed structure  128 . Alternatively, the domed structure  128  may be an overmolded component overmolded over a portion of the inner scissor member  142   b . In other cases, the domed structure  128  may be co-molded with the inner scissor member  142   b.    
     The domed structure  128  of  FIG. 4  may be affixed to the inner scissor member  142   b . As described above, the inner scissor member  142   b  may move or pivot in response to an actuation (e.g., depression) of the key cap  124 . In this regard, the domed structure  128  may correspondingly move or pivot along with the inner scissor member  142   b . This movement of the domed structure  128  may be configured to produce a predetermined tactile effect at the key cap  124  in response to a user input. For example, the key cap  124  may strike, impact, or otherwise press down on the domed structure  128  of  FIG. 4  in a manner that is tactilely distinguishable from other configurations of the keyboard assembly  108  in which the domed structure  128  is substantially stationary during actuation of the key cap  124 . 
       FIGS. 5A-5D  depict embodiments of the keyboard assembly  108  in which the backlight integrated membrane  232 , described herein with respect to  FIG. 1D , is directly coupled with a dome integrated switch housing. The dome integrated switch housing may be used to detect actuation of the key cap  124  and may aid in directing light to an illuminable portion of the key cap  124 . The dome integrated switch housing may include an overmolded switch housing that is overmolded over a domed structure  128  (which may be a tactile dome, as one example). This may enhance manufacturability of the keyboard assembly  108 , for example, by combining a keyboard switch housing and a domed structure into a single, integrated component. 
       FIG. 5A  depicts an illustrative exploded view of an embodiment of the keyboard assembly  108  shown in  FIG. 1A . As described herein, the keyboard assembly  108  may be formed from various layers of components that define a keyboard stack-up. Each layer and/or component of the stack-up of the keyboard assembly  108  may provide different functionality and/or operations for the electronic device  104 . Although a single key stack-up of keyboard assembly  108  is shown in  FIG. 5A , it is understood that substantially all keys (or a subset of keys) of the keyboard assembly  108  may be formed from similar components and/or layers in a similar configuration and/or function in a substantially similar manner as the single key stack-up shown in  FIG. 5A . 
     The keyboard assembly  108  may include the backlight integrated membrane  232 , such as the backlight integrated membrane  232  described with respect to  FIG. 1D . In the embodiment shown in  FIG. 5A , the backlight integrated membrane  232  may include top sheet  234   a , bottom sheet  234   b , membrane spacer  237 , and light emitting element  236 . As described above, the top sheet  234   a , the bottom sheet  234   b , and the membrane spacer  237  may cooperate to define a keyboard membrane circuit that initiates an input in response to a force exerted on the key cap  124 . For example, the top sheet  234   a  may be coupled with the terminals  250   a  and the bottom sheet  234   b  may be coupled with the terminal  250   b . The terminals  250   a ,  250   b  may complete an electrical circuit when the domed structure  128  collapses (or otherwise deforms) in response to an input force exerted on the key cap; this collapse forces the terminals  250   a ,  250   b  into physical contact and electrical connection with one another. The top and bottom sheets  234   a ,  234   b  may include electrical traces  251 , which may be used to transmit an electrical signal to a computing device when the circuit is completed. One or both of the top sheet  234   a  and the bottom sheet  234   b  may be transparent and aid in providing light to an illuminable portion of the key cap  124 . For example, one or both of the top sheet  234   a  or the bottom sheet  234   b  may propagate light received from the light emitting element  236  toward the illuminable portion of the key cap  124 . 
     The backlight integrated membrane  232  may be positioned below a web (defined or formed from the enclosure  112 ) and the key cap  124 . The backlight integrated membrane  232  may be coupled to and/or rest on a reflective component  180 ; for example, the reflective component  180  may be directly adhered to a bottom surface of the backlight integrated membrane  232 , or otherwise directly connected or affixed to the membrane. In some embodiments, the reflective component  180  may be a portion of the backlight integrated membrane  232 , or a reflective ink or other material applied to the membrane. 
     The reflective component  180  may have light reflective properties and may be configured to redirect stray light back into the backlight integrated membrane  232  or other component of the keyboard assembly  108 . More specifically, light generated by the light emitting element  236  may stray below one or both of the top sheet  234   a  or the bottom sheet  234   b . As a result of the light-reflective properties of the reflective component  180 , such stray light may be reflected back into the backlight integrated membrane  232 , through which the light may be subsequently redirected to an illuminable portion of the key cap  124 . The reflective component  180  may be constructed from a variety of substantially reflective materials including, but not limited to, stainless steel, aluminum, and/or other metallic or non-metallic components having substantially reflective properties. 
     The backlight integrated membrane  232  may be positioned below, and coupled with, a dome integrated switch housing  170 . The dome integrated switch housing  170  may be a structural portion of the keyboard assembly  108  that contains a deformable tactile dome or other domed structure used to detect actuation of the key cap  124 . The dome integrated switch housing  170  may also include various light extraction or illumination features that may direct light to an illuminable portion of the key cap  124 . 
     As shown in  FIG. 5A , the dome integrated switch housing  170  may be coupled with a butterfly mechanism  144  or other analogous support structure of the keyboard assembly  108 . The dome integrated switch housing  170  may support the key cap  124  using, for example, the butterfly mechanism  144  or other support structure of the keyboard assembly  108 . For example, the butterfly mechanism  144  may be pivotally connected to both of the dome integrated switch housing  170  and the key cap  124 . The butterfly mechanism  144  may pivot during actuation of the key cap  124  such that the key cap  124  remains structurally supported above the backlight integrated membrane  232  during actuation of the key cap  124 . In this regard, the dome integrated switch housing  170  may be a structural component of the keyboard assembly  108  that facilitates securing the key cap  124  above the backlight integrated membrane  232 . Additionally or alternatively, as described with respect to  FIG. 5B , the dome integrated switch housing  170  may include one or more posts  177  that extend from a top surface of the dome integrated switch housing  170  and provide a stop or cushion to the key cap  124  when the key cap  124  is sufficiently depressed. As such, the dome integrated switch housing  170  may support the key cap  124  through contact with the posts  177  or other features of the dome integrated switch housing  170 . 
     The backlight integrated membrane  232  may include various recesses, openings, or other features that are configured to secure and/or receive components of the keyboard assembly  108 . For example, the backlight integrated membrane  232  may include recesses  280  that extend through one or more of the top sheet  234   a , the membrane spacer  237 , and the bottom sheet  234   b . In some cases, the recesses  280  may extend through the reflective component  180  as well. The recesses  280  may be configured to receive a pivoting joint or portion of the butterfly mechanism  144 . This may help reduce the height of the keyboard assembly  108  by partially nesting the butterfly mechanism within the backlight integrated membrane  232 . The backlight integrated membrane  232  may also include mounting holes  282 . The mounting holes  282  may extend through one or more of the top sheet  234   a , the membrane spacer  237 , the bottom sheet  234   b , and/or the reflective component  180 . The mounting holes  282  may define mounting features at which the dome integrated switch housing  170  may be mounted to the backlight integrated membrane  232 . 
       FIG. 5B  depicts detail  2 - 2  of the dome integrated switch housing  170  depicted in  FIG. 5A . As shown in the non-limiting example of  FIG. 5B , the dome integrated switch housing  170  may include an overmolded switch housing  174  and the domed structure  128 . The overmolded switch housing  174  may be an overmolded component that is overmolded over a portion of the domed structure  128  (e.g., such as about a periphery  129  of the domed structure  128 ). In some cases, the overmolded switch housing  174  may have a hardness that is greater than a hardness of the domed structure  128 . 
     More generally, the overmolded switch housing  174  may be a structural component of the keyboard assembly  108 . For example, the overmolded switch housing  174  may structurally support the domed structure  128  within the keyboard assembly  108 . For example, the overmolded switch housing  174  may include or define feet  175 , as depicted in  FIG. 5B . The feet  175  may be configured to be secured to or received by the backlight integrated membrane  232  (e.g., the feet  175  may be received by the mounting holes  282 , described with respect to  FIG. 5A ). 
     Further the overmolded switch housing  174  may also serve to enhance the acoustic performance of the keyboard assembly  108 . In an embodiment, the overmolded switch housing  174  may include posts  177 . The posts  177  may be constructed from rubber or other acoustically insulating materials. The posts  177  may extend from a top surface of the overmolded switch housing  174 . The posts  177  may have a height or other dimension such that the key cap  124  impacts the posts  177  upon actuation. This may help dampen the sound associated with a key stroke. 
     The overmolded switch housing  174  may also include or define various light extraction features  178 . As explained in greater detail below with respect to  FIG. 5C , the light extraction features  178  may be configured to receive light from the backlight integrated membrane  232 . In this regard, the overmolded switch housing  174  may be used to illuminate an illuminable portion of the key cap  124 . 
     Further, the domed structure  128  and the overmolded switch housing  174  may form an interface within the dome integrated switch housing  170  in any appropriate manner. In some cases, as shown in  FIG. 5B , the dome integrated switch housing  170  may include a collar  171  between the domed structure  128  and the overmolded switch housing  174 . As explained in greater detail below with respect to  FIG. 5C , the collar  171  may be configured to reduce stress and strain within the domed structure  128  over time. 
       FIG. 5C  depicts a cross-sectional view of the keyboard assembly  108  of  FIG. 5A , taken along the line C-C of  FIG. 5A . Some of the layers or components of the keyboard assembly  108 , for example, the electrical traces  251 , have been omitted for clarity. The keyboard assembly  108  depicted in  FIG. 5C  is shown in an assembled configuration. As such, the dome integrated switch housing  170  is shown positioned on a surface of the backlight integrated membrane  232 . 
     As demonstrated above, the dome integrated switch housing  170  may include light extraction features  178 . The light extraction features  178  may be optically coupled with the backlight integrated membrane  232  such that the light extraction features  178  receive light from the light source  236 . The light extraction features  178  may be apertures, transparent sections, and/or other regions of the dome integrated switch housing  170  that are configured to propagate light within the keyboard assembly  108 . The light extraction features  178  are shown in  FIG. 5C  as extending through the dome integrated switch housing  170  at the overmolded switch housing  174 . However, it will be appreciated that the light extraction features  178  may be positioned at the domed structure  128  and/or any other appropriate position or orientation with the dome integrated switch housing  170 , including embodiments in which the light extraction features  178  are positioned at least partially within the overmolded switch housing  174  and the domed structure  128 . 
     The dome integrated switch housing  170  may be constructed in a manner that reduces stress and strain on the domed structure  128  over time. For example, a collar  171  may be defined about the periphery  129  of the domed structure  128 . The collar  171  may be an integral or unitary component of the domed structure  128 , the overmolded switch housing  174 , and/or may be a separate overmolded component of the dome integrated switch housing  170 . 
     In one embodiment, the collar  171  may reduce stress and strain within the domed structure  128  when the key cap  124  is depressed. For example, depression of the key cap  124  may cause an upper portion of the domed structure  128  to translate and deform until the domed structure  128  buckles (e.g., collapses). Continued depression of the key cap  124  may create an overloaded condition in which the domed structure  128  bows, collapses, or extends in a direction transverse to the depression of the key cap  124 . The collar  171  may resist collapse or other deformation of the domed structure  128  when it is in the overloaded condition. For example, the collar  171  may physically obstruct deformation or collapse of the domed structure  128  beyond a predetermined point due to the abutment or positioning of the collar  171  about the periphery  129 . It will be appreciated that the collar  171  may have any appropriate physical attributes (e.g., rigidity, thickness, height, and so on) to resist deformation of the domed structure  128  in an overloaded condition. 
     The dome integrated switch housing  170  may also be used with various sensing elements that are configured to detect a range of deformations of the domed structure  128  (up to, and including, collapse). For example, the keyboard assembly  108  may include a sense layer  176   a  positioned on a surface of the dome integrated switch housing  170  and a drive layer  176   b  positioned on a surface of the key cap  124 . The sense layer  176   a  and the drive layer  176   b  may collectively define an input or sensing element or structure that is configured to detect a translation and/or deformation of the domed structure  128  and/or the key cap  124 . 
     In one embodiment, the sense layer  176   a  and the drive layer  176   b  may be a pair of capacitive electrodes. In this manner, a capacitance between the sense layer  176   a  and the drive layer  176   b  may vary with a distance separating the sense layer  176   a  and the drive layer  176   b . Thus, a change in capacitance may be measured and correlated with, for example, a depression of the key cap  124  or similar input surface. When the change in capacitance exceeds a threshold, the keyboard assembly  108  may initiate a switch event (that is, generate an input signal). Additionally or alternatively, the capacitance may be associated with a range of non-binary inputs, including associated with a change in capacitance with a force received at the key cap  124  (e.g., by determining a force required to displace the domed structure  128  by an amount associated with a change in distance between the sense layer  176   a  and the drive layer  176   b ). 
     In this regard, the sense layer  176   a , the drive layer  176   b  (or any other suitable sensing element), and the backlight integrated membrane  232  may cooperate to detect multiple deformations of the domed structure  128 . As one example, electrical traces on the backlight integrated membrane  132  may be electrically connected by a first deformation of the domed structure  128 , which may correspond to an initial collapsing or buckling of the domed structure  128 . The sense layer  176   a  and the drive layer  176   b  may operate to detect a second deformation of the domed structure  128 , as described above, which may correspond to a subsequent deformation of the domed structure  128 . 
     As demonstrated by the assembled configuration of  FIG. 5C , the keyboard assembly  108  may have a reduced thickness, due in part to the domed structure  128  being positioned within the overmolded switch housing  174 . For example, a portion of the domed structure  128  may be nested within a thickness of the overmolded switch housing  174 . This nesting may help reduce the height of the keyboard. Further, the light guide and the circuit layer of the keyboard assembly  108  are included within the backlight integrated membrane  232 , which further reduces thickness. 
       FIG. 5D  depicts a cross-sectional view of another embodiment of the keyboard assembly  108  of  FIG. 5A , taken along line C-C of  FIG. 5A . Some of the layers or components of the keyboard assembly  108 , for example, the electrical traces  151 , have been omitted for clarity. In particular, in the embodiment of  FIG. 5D , the dome integrated switch housing  170  is shown coupled with the backlight integrated membrane  132 , described with respect to  FIGS. 1B and 2A-4 . In this regard, the backlight integrated membrane  132  may be configured to detect actuation of the key cap  124  using the domed structure  128  as overmolded or contained within the overmolded switch housing  174 . Additionally, the backlight integrated membrane  132  may be configured to illuminate an illuminable portion of the key cap  124 , such as illuminable surface  126 , using the dome integrated switch housing  170 . 
       FIG. 5E  depicts a cross-sectional view of another embodiment of the keyboard assembly  108  of  FIG. 5A , taken along line C-C of  FIG. 5A . Some of the layers or components of the keyboard assembly  108 , for example, the electrical traces  251 , have been omitted for clarity. In particular, in the embodiment of  FIG. 5E , the light emitting element  236  is shown positioned on a surface of the top sheet  234   a . For example, the light emitting element  236  may be positioned on a lateral surface of the top sheet  234   a  and below the key cap  124  or other input surface. The light emitting element  236  may be optically coupled with the top sheet  234   a  such that the backlight integrated membrane  232  may direct light to various regions within the keyboard assembly  108 . 
     In some cases, as shown in  FIG. 5E , the light emitting element  236  may be positioned within, beneath, or formed as a component of, the dome integrated switch housing  170 . For example, the light emitting element  236  may be positioned within a volume defined by the overmolded switch housing  174  (e.g., beneath the housing). In this regard, the dome integrated switch housing  170  may receive light directly from the light emitting element  236 . In turn, the dome integrated switch housing  170  may propagate the light received from the light emitting element  236  to various regions of the keyboard assembly  108 , which may facilitate or cause an illuminable portion of the key cap  124  to illuminate. To facilitate the foregoing, at least a portion of the dome integrated switch housing  170  (including portions of the domed structure  128  and/or the overmolded switch housing  174 ) may be made of a transparent material. 
     Other examples and implementations are within the scope and spirit of the disclosure and appended claims. For example, features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Similarly, although embodiments have been discussed in the context of keys of a keyboard, other input mechanisms may incorporate or form embodiments described herein. As an example, trackpads, mice, buttons, touch-sensitive surfaces, and the like may all incorporate structures and/or methods of operation described herein. Also, as used herein, including in the claims, “or” as used in a list of items prefaced by “at least one of” indicates a disjunctive list such that, for example, a list of “at least one of A, B, or C” means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Further, the term “exemplary” does not mean that the described example is preferred or better than other examples. 
     The foregoing description, for purposes of explanation, uses specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not targeted to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

Metadata:
Filing Date: 20170525
Publication Date: 20190709
Grant Date: 20190709
Priority Date: 20170525
Inventors: WU, CHIA CHI
WANG, PAUL X.
LEHMANN, Alex J.
CHEN, CHIEN-TSUN
CHIN, KUO-CHIANG
GAO, MING
GAO, ZHENG
Assignee: APPLE INC
CPC Classifications: [{"code": "H01H2227/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2219/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B6/0023", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/0021", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/83", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/0076", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2215/012", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2219/062", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0202", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H3/125", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/83", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H13/83", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H2219/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0202", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/0023", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2219/062", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0202", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 67106452