PATENT DOCUMENT

Publication Number: US-10083806-B2
Application Number: US-201615269790-A
Country: US
Kind Code: B2

Title: Keyboard for electronic device

Abstract:
An input mechanism is disclosed. The input mechanism includes a dome support structure defining an opening that extends through the dome support structure, a collapsible dome positioned in the opening and engaged with the dome support structure, and a cover member coupled to the dome support structure and covering the collapsible dome, thereby retaining the collapsible dome within the opening of the dome support structure.

Claims:
What is claimed is: 
     
       1. A keyboard, comprising:
 a substrate defining a first opening and a second opening; 
 a keycap; and 
 a butterfly hinge supporting the keycap above the substrate and comprising:
 a first wing comprising:
 a first cross-beam overlapping the first opening; and 
 a first pair of arms extending from the first cross-beam; and 
 
 a second wing coupled to the first wing and comprising:
 a second cross-beam overlapping the second opening; and 
 a second pair of arms extending from the second cross-beam; and 
 
 a living hinge comprising a flexible material; wherein the living hinge joins an end of a first arm of the first pair of arms to an end of a second arm of the second pair of arms, thereby coupling the first wing to the second wing. 
 
 
     
     
       2. The keyboard of  claim 1 , wherein:
 the substrate is a printed circuit board; 
 the first wing further comprises:
 a first keycap pivot pin extending from a first end of the first cross-beam; and 
 a second keycap pivot pin extending from a second end of the first cross-beam opposite the first end of the first cross-beam; 
 
 the second wing further comprises:
 a third keycap pivot pin extending from a first end of the second cross-beam; and 
 a fourth keycap pivot pin extending from a second end of the second cross-beam opposite the first end of the second cross-beam; and 
 
 the keycap is coupled to the butterfly hinge via the first, second, third, and fourth keycap pivot pins. 
 
     
     
       3. The keyboard of  claim 1 , wherein:
 the keyboard further comprises a switch body attached to the substrate; and 
 the first wing and the second wing are pivotally coupled to the switch body. 
 
     
     
       4. The keyboard of  claim 1 , wherein the first cross-beam comprises a recess formed therein, the recess overlapping the first opening. 
     
     
       5. The keyboard of  claim 1 , wherein:
 the substrate further defines a third opening and a fourth opening; 
 one of the arms of the first pair of arms overlaps the third opening; and 
 the other arm of the first pair of arms overlaps the fourth opening. 
 
     
     
       6. The keyboard of  claim 5 , wherein:
 the substrate further defines a fifth opening and a sixth opening; 
 one of the arms of the second pair of arms overlaps the fifth opening; and 
 the other arm of the second pair of arms overlaps the sixth opening. 
 
     
     
       7. A keyboard, comprising:
 a substrate defining an opening; 
 a keycap; and 
 a support mechanism supporting the keycap above the substrate and allowing the keycap to move between a depressed position and an undepressed position, the support mechanism comprising:
 a wing comprising:
 a cross-beam; and 
 a pair of arms extending from the cross-beam; wherein 
 
 
 the cross-beam comprises a recess; 
 the opening in the substrate is below the cross-beam; 
 the recess and the opening in the substrate define an empty space when the keycap is in the depressed position; and 
 the empty space is at least partially below the cross-beam and is configured to receive debris therein. 
 
     
     
       8. The keyboard of  claim 7 , wherein a portion of the cross-beam is substantially flush with the substrate when the keycap is in the depressed position. 
     
     
       9. The keyboard of  claim 7 , wherein:
 the substrate defines an additional opening; and 
 the support mechanism comprises an additional wing, comprising:
 an additional cross-beam configured to cooperate with the additional opening in the substrate to define an additional empty space below the additional cross-beam when the keycap is in the depressed position; and 
 a pair of additional arms extending from the additional cross-beam. 
 
 
     
     
       10. The keyboard of  claim 9 , wherein the cross-beam comprises an additional recess formed therein, the additional recess cooperating with the additional opening in the substrate to define the additional empty space. 
     
     
       11. The keyboard of  claim 10 , wherein less than half of an area of a bottom side of the support mechanism contacts the substrate when the keycap is in the depressed position. 
     
     
       12. The keyboard of  claim 9 , wherein the wing and the additional wing are coupled together via a living hinge connecting one arm of the pair of arms to one arm of the pair of additional arms. 
     
     
       13. The keyboard of  claim 4 , wherein the recess cooperates with the first opening to define an empty space when the keycap is in a depressed position. 
     
     
       14. A keyboard, comprising:
 a keycap; 
 a substrate below the keycap; 
 a switch body attached to the substrate; and 
 a support mechanism supporting the keycap above the substrate and allowing the keycap to move between a depressed position and an undepressed position, the support mechanism comprising:
 a first wing comprising:
 a first arm pivotally coupled to the switch body and the keycap; 
 a second arm pivotally coupled to the switch body and the keycap; and 
 a first cross-beam extending between the first arm and the second arm; 
 
 a second wing coupled to the first wing, comprising:
 a third arm pivotally coupled to the switch body and the keycap; 
 a fourth arm pivotally coupled to the switch body and the keycap; and 
 a second cross-beam extending between the third arm and the fourth arm; and 
 
 a living hinge comprising a flexible material joining an end of the first arm to an end of the third arm; 
 
 wherein the substrate defines an opening positioned below the first cross-beam and configured to define an empty space below the first cross-beam when the keycap is in the depressed position. 
 
     
     
       15. The keyboard of  claim 14 , wherein:
 the opening is a first opening; 
 the empty space is a first empty space; 
 the substrate further defines a second opening positioned below the first arm and configured to define a second empty space below the first arm when the keycap is in the depressed position; and 
 the substrate further defines a third opening positioned below the second arm and configured to define a third empty space below the second arm when the keycap is in the depressed position. 
 
     
     
       16. The keyboard of  claim 15 , wherein:
 the first wing and the second wing cooperate to define a fourth opening between the first, second, third, and fourth arms; and 
 the switch body is within the fourth opening when the keycap is in the depressed position. 
 
     
     
       17. The keyboard of  claim 14 , wherein the flexible material is an elastomeric material at least partially encapsulating a terminal portion of the first arm and a terminal portion of the third arm. 
     
     
       18. The keyboard of  claim 15 , wherein the first cross-beam comprises a recess configured to align with the first opening and cooperate with the first opening to define the first empty space when the keycap is in the depressed position. 
     
     
       19. A laptop computer comprising:
 a display portion; 
 a display positioned at least partially within the display portion; 
 a base portion pivotally coupled to the display portion; 
 a keyboard at least partially within the base portion and comprising a key; wherein 
 the key comprises:
 a keycap; 
 a switch body below the keycap; and 
 a support mechanism supporting the keycap and allowing the keycap to move between a depressed position and an undepressed position, the support mechanism comprising:
 a first wing comprising:
 a first cross-beam; and 
 a first pair of arms extending from the first cross-beam; and 
 
 a second wing coupled to the first wing and comprising:
 a second cross-beam; and 
 a second pair of arms extending from the second cross-beam; and 
 
 a living hinge coupling the first wing to the second wing and comprising an elastomeric material at least partially encapsulating one of the first pair of arms and one of the second pair of arms. 
 
 
 
     
     
       20. The laptop computer of  claim 19 , wherein:
 the base portion further comprises a substrate; 
 the switch body is attached to the substrate; and 
 the substrate defines an opening positioned below the first cross-beam. 
 
     
     
       21. The laptop computer of  claim 20 , wherein:
 the first cross-beam defines a recess; and 
 the recess cooperates with the opening to define an empty space below the first cross-beam when the keycap is in a depressed position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation patent application of U.S. patent application Ser. No. 15/154,768, filed May 13, 2016 and titled “Keyboard for Electronic Device,” which is a nonprovisional patent application of U.S. Provisional Patent Application No. 62/214,590, filed Sep. 4, 2015 and titled “Film-Based Housing and Switch for Keyboard Assembly,” U.S. Provisional Patent Application No. 62/233,975, Sep. 28, 2015 and titled “Illumination Structure for Illumination of Keys,” U.S. Provisional Patent Application No. 62/161,038, filed May 13, 2015 and titled “Uniform Illumination of Keys,” U.S. Provisional Patent Application No. 62/161,020, filed May 13, 2015 and titled “Keyboard Assemblies Having Reduced Thicknesses and Method of Forming Keyboard Assemblies,” U.S. Provisional Patent Application No. 62/161,103, filed May 13, 2015 and titled “Low-Travel Key Mechanism for an Input Device,” the disclosures of which are hereby incorporated herein by reference in their entireties. 
    
    
     FIELD 
     The described embodiments relate generally to electronic devices, and more particularly to input devices for electronic devices. 
     BACKGROUND 
     Many electronic devices include one or more input devices such as keyboards, touchpads, mice, or touchscreens to enable a user to interact with the device. These devices can be integrated into an electronic device or can stand alone as discrete devices that can transmit signals to another device either via wired or wireless connection. For example, a keyboard can be integrated into the housing of a laptop computer or it can exist in its own housing. 
     The keys of a keyboard may include various mechanical and electrical components to facilitate the mechanical and electrical functions of the keyboard. For example, a key may include mechanical structures to allow the key to move or depress when actuated, as well as electrical components to allow an electrical signal to be produced in response to actuation. Due to the relatively small size of such components, as well as the relatively high number of such components contained in a keyboard, designing and manufacturing keyboards may be complex and difficult undertakings. 
     SUMMARY 
     An input mechanism includes a dome support structure defining an opening that extends through the dome support structure, a collapsible dome positioned in the opening and engaged with the dome support structure, and a cover member coupled to the dome support structure and covering the collapsible dome, thereby retaining the collapsible dome within the opening of the dome support structure. 
     An input mechanism includes a frame defining a retention channel along an outer edge of the frame and an opening in a central region of the frame. The input mechanism further includes a cover member positioned over the opening and a collapsible dome positioned in the opening and captured between the cover member and a retention feature of the frame. The retention channel is configured to capture a pivot member between a wall of the retention channel and an object adjacent the frame. 
     A method of assembling a keyboard includes assembling an input subassembly and coupling the input subassembly to a base plate. Assembling the input subassembly includes positioning a collapsible dome in an opening of a dome support structure to engage the collapsible dome with the dome support structure and coupling a cover member to the dome support structure such that the collapsible dome is retained between the cover member and a retention surface of the dome support structure. 
     A collapsible dome includes a dome portion comprising a concave surface defining an interior volume, a protruding member extending into the interior volume from the dome portion, and an array of suspension arms extending from an outer edge of the dome portion. 
     A collapsible dome includes a dome portion and an array of arms extending from an outer edge of the dome portion. The arms are configured to contact a base plate. In response to an actuation force applied to the dome portion, the arms are configured to collapse in response to a first deflection distance, and the dome portion is configured to collapse after the arms collapse in response to a second deflection distance greater than the first deflection distance. The dome portion may be configured to contact the base plate when the arms and the dome portion collapse. The dome portion may define a concave surface defining an interior volume, and the collapsible dome may further comprise an actuation arm extending into the interior volume. The actuation arm may be configured to contact the base plate after the dome portion collapses in response to the actuation force. The dome may further comprise a travel limiting feature configured to limit an amount of deflection of the actuation arm in response to the actuation force. The travel limiting feature may be a protrusion extending from a surface of the dome portion into the interior volume. 
     An electronic device includes a housing and a keyboard positioned at least partially within the housing. The keyboard includes a base plate positioned within the housing, and a switch housing positioned on the base plate. The switch housing includes pin retention features formed on a peripheral edge of the switch housing. The electronic device also includes an actuation mechanism retained to the base plate with the switch housing. The actuation mechanism includes a pair of wings defining an opening, a hinge coupling the wings together, and pins extending from each wing into respective pin retention features. The switch housing is positioned in the opening of the actuation mechanism. 
     A key includes a collapsible dome, a keycap positioned above the collapsible dome, a light source, and a light guide positioned at least partially around the collapsible dome and optically coupled to the light source. The light guide includes a light-directing feature operative to direct light around the light guide, a reflection feature operative to reflect the light internally around the light guide, and an illumination feature operative to illuminate the keycap. 
     A key includes a collapsible dome, a light source, and a light guide positioned at least partially around the collapsible dome and optically coupled to the light source. 
     An input mechanism includes a switch housing defining an opening, a cover member attached to a surface of the switch housing and covering the opening, and an actuation pad on a surface of the cover member and positioned above the opening. The cover member may comprise an elastomeric material. The input mechanism may further comprise a collapsible dome positioned in the opening, and the actuation pad may be positioned over the collapsible dome. The switch housing may comprise an array of recesses, and the collapsible dome may comprise an array of arms, each arm being positioned in a respective recess. The elastomeric material may be substantially transparent. 
    
    
     
       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 structural elements, and in which: 
         FIG. 1  shows an example computing device incorporating a keyboard. 
         FIG. 2  shows an exploded view of the keyboard of  FIG. 1 . 
         FIGS. 3-4  show exploded views of a key. 
         FIGS. 5A-5D  show exploded views of the key of  FIG. 3  at different stages of an assembly operation. 
         FIG. 6  shows a partial cross-sectional view of the key of  FIG. 3  viewed along line  6 - 6  in  FIG. 3 . 
         FIGS. 7A-7D  show a dome support structure of the key of  FIG. 3 . 
         FIGS. 8A-8B  show partial cross-sectional views of the key of  FIG. 3  viewed along line  8 - 8  in  FIG. 3 . 
         FIG. 9  shows a collapsible dome of the key of  FIG. 3 . 
         FIGS. 10A-10C  show cross-sectional views of the collapsible dome of  FIG. 9 , viewed along line  10 - 10  in  FIG. 9 . 
         FIG. 11  shows a force versus travel curve of the key of  FIG. 3 . 
         FIG. 12  shows a butterfly hinge of the key of  FIG. 3 . 
         FIGS. 13-24  show examples of living hinges usable in the butterfly hinge of  FIG. 12 . 
         FIG. 25  shows the key of  FIG. 3 . 
         FIGS. 26A-29B  show partial cross-sectional views of the key of  FIG. 3  viewed along line  26 - 26  in  FIG. 25 . 
         FIGS. 30A-30B  show schematic views of butterfly hinges for use in the key of  FIG. 3 . 
         FIG. 31  shows a partial view of the key of  FIG. 3 . 
         FIG. 32A  shows a partial cross-sectional view of the key of  FIG. 3  viewed along line  32 A- 32 A in  FIG. 31 . 
         FIG. 32B  shows a partial cross-sectional view of the key of  FIG. 3  viewed along line  32 B- 32 B in  FIG. 31 . 
         FIG. 33  shows an exploded view of an example key. 
         FIG. 34  shows a flow chart of an example method of assembling a keyboard. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims. 
     Keyboards use various different mechanisms to provide mechanical and electrical functionality. For example, keys may include springs or domes to bias the keys to an undepressed or unactuated position, and articulating mechanical structures to moveably couple the keys to a base of the keyboard. Keys may also include electrical contacts, terminals, or switches to detect when a key has been depressed or actuated in order to provide a corresponding input signal to an electronic device. 
     Manufacturing a keyboard can be challenging. For example, the trend towards smaller devices, such as thinner computers and keyboards, as well as the general requirement for most keyboards to be easily actuated by the fingertips of a person, means that the individual mechanisms are often relatively small. Moreover, keyboards require that a large number of small components be accurately and precisely aligned in order for the device to operate properly. If even one key in a fully assembled keyboard is not working properly, the entire keyboard may be deemed defective. Accordingly, described herein is a keyboard, and components thereof, that can be manufactured with a high degree of accuracy and precision and that results in a low failure rate for the completed keyboards. The modularized components and/or subassemblies described herein may allow more efficient and accurate assembly of keyboards, among other possible benefits, such as the ability to individually test components and subassemblies before they are assembled into a final product. 
     As described herein, several components of a key may be assembled into a modularized unit or subassembly that can be easily coupled or otherwise attached to a keyboard base. More particularly, a switch assembly including a dome, a switch housing, and a cover member may be pre-assembled for the keys. The dome may be retained in an opening of the switch housing such that the switch assembly forms a single modular unit that can be coupled to a keyboard base. Because the switch assembly is pre-assembled with the dome retained to the switch housing, it can be more easily handled by manufacturing equipment including pick-and-place machines, tape-and-reel machines, or other automation equipment. Moreover, because the dome is retained to the switch housing, it may not be necessary to separately align and/or couple the dome to the keyboard base. By contrast, separately coupling a switch housing and a dome to a base increases the chances that a misaligned part will render a keyboard defective. 
     The switch assembly may also include an actuation mechanism, such as a butterfly hinge, that is retained to the keyboard base by the switch housing. For example, the switch housing may include retention channels along an outer periphery or peripheral edge of the switch housing, where the open end of the retention channel is configured to be placed against the keyboard base. Pivot pins or other pivot members of a butterfly hinge may be placed into the channels prior to the switch assembly being coupled to the keyboard base, and the switch assembly and the butterfly hinge may be coupled to the keyboard base. Thus, the pivot pins are captured between the keyboard base and the walls of the retention channel, thereby retaining the butterfly hinge to the keyboard base while also positioning the butterfly hinge relative to the keyboard base and the switch housing. Because the butterfly hinge can be pre-assembled with the switch assembly prior to being coupled to the keyboard base, the butterfly hinges may not need to be separately aligned with and coupled to the keyboard base. 
     The dome that is used in the switch assembly may include features that engage the switch housing to retain the dome to the switch housing, and may also be configured to engage electrical contacts on the keyboard base to register an input when the key is actuated. For example, the dome may include curved arms extending from an outer edge of the dome. The curved arms may engage a feature of the switch housing to retain the dome to the housing. Moreover, a portion of an arm may contact an electrical terminal on the keyboard base when the switch assembly is coupled thereto. Thus, the process of coupling a switch assembly to the keyboard base not only accurately locates and couples the switch housing, the dome, and the butterfly hinge to the keyboard base, but it also makes an appropriate electrical connection between the dome and the electrical terminals of the keyboard. 
       FIG. 1  shows a computing device  100  having a housing  104  and a keyboard  102  incorporated therein. The keyboard  102  may be positioned at least partially within the housing  104 . 
     As shown, the computing device  100  (or “device  100 ”) is a laptop computer, though it can be any suitable computing device, including, for example, a desktop computer, a smart phone, an accessory, or a gaming device. Moreover, while the keyboard  102  in  FIG. 1  is incorporated with the computing device  100 , the keyboard  102  may be separate from a computing device. For example, the keyboard  102  may be a standalone device that is connected (via a cable or wirelessly) to a separate computing device as a peripheral input device. The keyboard  102  may also be integrated into another product, component, or device, such as a cover or case for a tablet computer. In such cases, the housing  104  may refer to a housing of any product, component, or device in which the keyboard  102  is integrated or otherwise positioned. 
     The computing device  100  may also include a display  106  within the housing  104 . For example, the display  106  may be within or otherwise coupled to a first portion  108  of the housing  104  that is pivotally coupled to a second portion  110  of the housing  104 . The keyboard  102  may be within or otherwise coupled to or incorporated with second portion  110  of the housing  104 . 
     The keyboard  102  includes a plurality of keys, including a representative key  105 . While the instant application describes components of a representative key  105  of a keyboard  102 , the concepts and components described herein apply to other depressible input mechanisms as well, including buttons, standalone keys, switches, or the like. Moreover, such keys, buttons, or switches may be incorporated into other devices, including smart phones, tablet computers, or the like. 
       FIG. 2  shows an exploded view of the keyboard  102 . The keyboard  102  includes a web  202 , keycaps  204 , switch assemblies  206 , and a base plate  208 . As used herein, keycaps  204  and switch assemblies  206  may be discussed individually or collectively. It will be understood that a discussion relating to any individual keycap  204  or switch assembly  206  may apply equally to any other keycap or switch assembly of the keyboard  102 . 
     The web  202  may be part of the second portion  110  of the housing  104  ( FIG. 1 ), and may define a plurality of apertures  203  configured to receive keycaps  204  therein. The web  202  may also include other apertures (not shown) for other buttons, input mechanisms, touchpads, microphones, lights, speakers, or other components. 
     The keycaps  204  are coupled to the switch assemblies  206  and are configured to be manipulated (e.g., pressed or actuated) by a user to provide input to the device  100 . For example, the keycaps  204  may be positioned over collapsible domes (e.g., the dome  402 ,  FIG. 4 ) such that when the keycaps  204  are pressed, the collapsible domes are collapsed to actuate the key and register an input. 
     The keycaps  204  may include optical elements or materials that are configured to transmit light therethrough. For example, the keycaps  204  may include transparent or translucent portions  315  ( FIG. 3 ) corresponding to glyphs or other symbols commonly found on keycaps. A light from a light source associated with the keycap may be transmitted through such portions to illuminate the keycap. In some cases, a keycap may be formed entirely from a transparent or translucent material. Alternatively, a keycap may have transparent or translucent as well as opaque portions. For example, a keycap may be formed entirely from a transparent or translucent material, and may include a substantially opaque painting, coating, or other layer disposed on a portion of the keycap to produce optical regions within the keycap. As another example, a keycap may be formed with openings corresponding to glyphs, which may be filled with transparent or translucent materials to form illuminable glyphs. 
     The switch assemblies  206  comprise components that provide mechanical and electrical operations of the key. For example, as described herein, the switch assemblies  206  include a switch housing, a dome, and an actuation mechanism (e.g., a butterfly hinge or other hinge mechanism, scissor mechanism, or the like). The switch assemblies  206  may be pre-assembled prior to being coupled to the base plate  208 . The switch assemblies  206  may be referred to as input subassemblies. In particular, as described herein, the switch assemblies  206  may be assembled into a modular subassembly prior to being incorporated into a keyboard or other input mechanism. In such cases, the switch assemblies  206  are subassemblies for the overall input mechanism. 
     The keyboard  102  also includes a base plate  208 . The base plate  208  may be a single component (e.g., a single monolithic structure, such as a single circuit board or other substrate), or may be composed of multiple layers. For example, the base plate  208  may include multiple layers including any of printed circuit boards, membranes, flexible circuit layers, conductive layers, or the like. The base plate  208  may be positioned within and/or coupled to the housing  104 . 
     The switch assemblies  206  may be coupled to the base plate  208 . For example, the switch assemblies  206 , or a portion thereof, may be glued, staked, screwed, or otherwise coupled to the base plate  208 . The base plate  208  may be a circuit board (e.g., a printed circuit board), a housing component of an electronic device, or any other component or substrate to which the switch assemblies  206  may be coupled. 
     The base plate  208  may include electrical contacts that interact with the domes of the switch assemblies  206  to detect actuations of the keys. For example, the base plate  208  may be a printed circuit board with conductive traces thereon. When a switch assembly  206  is coupled to the circuit board, the dome may be positioned such that, when that key is actuated, the dome forms or completes an electrical path between two conductive traces. 
     The base plate  208  also defines a plurality of openings  210 . Some of the openings  210  may receive components of the switch assemblies  206  therein. For example, portions of a butterfly hinge or a keycap may extend into an opening  210  when the key is actuated or depressed. Some of the openings  210  may also or instead provide clearance between components of the switch assemblies  206  and the base plate  208 , such that debris or other contaminants do not interfere with the movement of the key. Examples of the openings  210  are described herein. 
       FIG. 3  shows an exploded view of a representative key  105 . The key  105  includes a keycap  204 , a switch assembly  206 , and a base  303  (which may be a portion of the base plate  208 ). The switch assembly  206  in  FIG. 3  includes a switch package  302  and an actuation mechanism, such as a butterfly hinge  304  or other hinge mechanism. The switch package  302 , described in greater detail with respect to  FIG. 4 , includes a dome  402  ( FIG. 4 ), a dome support structure  314 , and a cover member  316 . 
     The butterfly hinge  304  allows the keycap  204  to move between a depressed and an undepressed position, and may include a first wing  306 , a second wing  308 , and a hinge  310  coupling the first wing  306  to the second wing  308 . The hinge  310  may include any appropriate coupling mechanism or material that attaches the first wing  306  to the second wing  308  while allowing the first wing  306  and the second wing  308  to articulate or move relative to each other. For example, the hinge  310  may include a gear hinge or a living hinge (e.g., a flexible material coupled to both the first and second wings  306 ,  308 ). 
     In the depicted example, the actuation mechanism is a butterfly hinge. However, this is merely one example of an actuation mechanism that may be used in a switch assembly  206 , and other actuation mechanisms may be used instead of the butterfly hinge  304  in any given key, including scissor mechanisms, hinge mechanisms, or any other mechanism that movably supports a keycap relative to the switch package  302  or the base  303  (or any other appropriate component). 
     The keycap  204  may be coupled to the first and second wings  306 ,  308  via pins  318  extending from the first and second wings  306 ,  308 . The keycap  204  may include retention clips  320  extending from an underside of the keycap  204  that engage the pins  318 . One pair of the retention clips  320  may allow its corresponding pins  318  to rotate therein, while another pair may allow its corresponding pins  318  to rotate and slide therein. When the key  105  is actuated (e.g., pressed downward) the ends of the first and second wings  306 ,  308  where the pins  318  are located will move away from one another. By including at least a pair of retention clips  320  that allow the pins to slide relative to the keycap  204 , the wings  306 ,  308  can articulate relative to one another without being mechanically bound by the retention clips  320 . 
     As shown in  FIG. 3 , the base  303  may include a light source  312 . (Indeed, the base plate  208  may include multiple light sources  312 , such as at least one light source for each key  105 , or any other appropriate number or distribution of light sources.) The light source may be a light emitting diode (LED), a fluorescent bulb, or any other appropriate light emitting device. The light source may also be a light guide or a light pipe that guides light from a remote light source to the location where the light source  312  is illustrated. The light source  312 , or a terminal end of a light guide or light pipe, may be positioned on the base  303  such that, when the switch assembly  206  is attached to the base  303 , the light source  312  is positioned proximate a light input surface of the switch package  302 . The light input surface, as well as other optical properties of the switch package  302  are discussed herein. 
     The configuration of the switch assembly  206  in  FIG. 3 , and in particular the relative arrangement of the switch package  302  and the butterfly hinge  304 , may correspond to a state immediately prior to the switch assembly  206  being coupled to the base  303 . For example, the butterfly hinge  304  may be coupled to or engaged with the switch package  302  to form a subassembly that can then be placed on and/or coupled to the base  303 . Machines, including pick-and-place machines, tape-and-reel machines, surface mount technology (SMT) machines, or any other component placement apparatus may assemble the switch assembly  206  as shown in  FIG. 3 , position the switch assembly  206  relative to the base  303 , and then place the switch assembly  206  on the base  303 . As described herein, the process of placing the switch assembly  206  on the base  303  may capture pivot pins or other pivot members of the butterfly hinge between the base  303  and a wall of a channel or recess in the dome support structure  314 . This configuration may allow for the butterfly hinge  304  to be retained to the base plate  208  without an additional processing and/or handling step during manufacturing. For example, because the butterfly hinge  304  and the switch package  302  are pre-assembled into an input subassembly, only one placement operation is needed to couple both the butterfly hinge  304  and the switch package  302  to the base  303 . This may increase the speed and efficiency with which a keyboard can be assembled, as it reduces the number of discrete placement operations. 
       FIG. 4  shows an exploded view of the key  105 , showing the components of the switch assembly  206  and the switch package  302  separated from one another. As noted above, the switch package  302  includes a dome support structure  314 . The dome support structure  314  may be any structure or component that supports a dome, including a frame, a housing, a portion of a circuit board, or the like. The dome support structure  314 , which may also be referred to as a switch housing or a frame, may perform various mechanical and/or electrical functions of the key  105 , such as housing and supporting a dome, coupling the dome to a base plate, providing mounting and/or coupling features for an actuation mechanism, and the like. The dome support structure  314  defines an opening  404  that extends through a thickness of the dome support structure  314  (e.g., from a top surface to a bottom surface of the dome support structure  314 ). 
     A dome  402 , which may be a collapsible dome, is positioned in the opening  404  and is engaged with the dome support structure  314 . For example, the dome  402  may include an array of retention features  406  (which may be arms or other members, protrusions, or features) extending from an outer edge of the dome  402 . Each retention feature  406  may contact or otherwise engage a respective retention surface  408  of the dome support structure  314  to retain the dome  402  to the dome support structure  314 . More particularly, the retention features  406  may overlap the retention surfaces  408  to retain the dome  402  in the opening  404  in at least one direction (e.g., to hold the dome upward, as depicted in  FIG. 4 ). The retention surfaces  408  may be positioned in recesses formed into the dome support structure  314 . For example, the retention features  406  (or arms) may be evenly spaced around the dome  402  and may extend radially from the dome  402 . The opening  404  in the dome support structure  314  may include corresponding evenly spaced, radially extending recesses into which the retention features  406  extend. 
     The dome  402  may be any appropriate type of dome, and may be formed from or include any appropriate material. For example, the dome  402  may be a collapsible dome, and may be formed from metal, polymer (e.g., an elastomeric material), or the like. An example dome  402  used in the key  105  is described herein. 
     A cover member  316  is coupled to the dome support structure  314  and covers the dome  402 . The cover member  316  may be or may include a flexible or compliant material (e.g., thermoplastic polyurethane, silicone, or any other appropriate elastomeric or flexible material) that deforms when subjected to an actuation force from the keycap  204  ( FIG. 3 ). The cover member  316  may include an actuation pad  410  configured to transmit the actuation force from the keycap  204  ( FIG. 3 ) to the dome  402 . The cover member  316  and the actuation pad  410  may be a single, monolithic component. The cover member  316  may be coupled to the dome support structure  314  using an adhesive, ultrasonic welding, laser welding, mechanical engagement, heat staking, or any other appropriate technique. The cover member  316  may be transparent and/or translucent. For example, the cover member  316  may cover all or part of a light guide  702  ( FIG. 7 ) of the dome support structure  314 , and may be transparent and/or translucent to allow light to pass through the cover member  316  to a glyph or other optical element in a keycap. 
     While the retention surfaces  408  support the dome  402  from the bottom, the cover member  316  supports the dome  402  from above, thus retaining the dome  402  to the dome support structure  314 . This configuration results in a self-contained, modular switch package  302  that can be easily moved, manipulated, and assembled with other components. In particular, because the dome is securely retained to the dome support structure  314  (e.g., held between the retention surfaces and the cover member), it can be pre-assembled prior to a final assembly of the keyboard. Retaining the dome  402  to the dome support structure  314  may obviate the need to individually position and couple domes to a base plate of a keyboard, a process that can lead to high manufacturing failure rates. More particularly, domes for keyboards may provide both mechanical and electrical functions for the individual keys, and proper alignment and coupling of the domes to the base plate may be critical to the proper functioning of the keyboard. Where the domes are each individually coupled to a base plate, a single defective or misaligned dome may cause an entire keyboard to be rejected. By coupling the dome  402  to the dome support structure  314  as described herein, the entire switch package  302  can be coupled to the base  303  with one coupling, reducing the chances of misalignment of any given component. Furthermore, because the dome  402  is retained to a mechanical structure prior to being coupled to a base  303 , the dome  402  (and indeed the entire switch package  302 ) can be individually tested prior to assembly into a final keyboard. Thus, defects in the domes (or other issues) that may have resulted in the scrapping of an assembled keyboard can be identified prior to assembly, thus increasing manufacturing yield. 
     The dome support structure  314  (which is shown as a frame but may be any other dome support structure or switch housing) may also define retention channels  412  (or other pin retention features) along a peripheral edge of the dome support structure  314 . For example, the dome support structure  314  may include four retention channels  412 , with two retention channels  412  formed in each of two opposing sides of the dome support structure  314 . The retention channels  412  may be substantially u-shaped, as shown, such that a pivot pin  414  (or other feature or member) of the butterfly hinge  304  can be introduced into the channel  412  through an opening in the channel  412 . The opening may be configured to face or be placed against another component (e.g., the base  303 ) such that the other component encloses the channel  412 , thus capturing the pivot pin  414  in the channel  412 . 
     The channels  412  and the butterfly hinge  304  (and in particular the pivot pins  414 ) may have a clearance fit, such that the pivot pins  414  can slide freely into the channels  412  (e.g., without obstruction and without requiring a temporary deformation of either the pins  414 , the butterfly hinge  304 , or the frame  314  or other dome support structure). The clearance fit between these components may help reduce stresses in the components during manufacturing and assembly of a keyboard. Also, the clearance fit may reduce the complexity of a pick-and-place operation (or other type of assembly procedure) to couple the butterfly hinge  304  to the dome support structure  314  prior to being coupled to the base  303 . For example, an assembly head may pick up the dome support structure  314 , and may thereafter pick up the butterfly hinge  304  such that the pivot pins  414  are slid into the channels  412 . The assembly head may hold both the butterfly hinge  304  and the dome support structure  314  (e.g., with a vacuum nozzle or other mechanism) so that they can be placed together on the base  303 . While channels  412  are shown, other pin retention features may be used instead of or in addition to the channels  412 . For example, the dome support structure or frame  314  may include detents, recesses, blind holes, walls, ledges, slots, and the like. 
     The dome support structure  314  may also include a light input surface  416 . When the key  105  is assembled, the light source  312  may be disposed proximate the light input surface  416  such that light emitted from the light source  312  enters the dome support structure  314  through the light input surface  416 . The dome support structure  314  may include or define a light guide  702  ( FIG. 7A ) that directs the light that is received through the light input surface  416  out of the dome support structure  314  and towards the keycap  204 . The light guide  702  and the optical properties of the dome support structure  314  are described in greater detail with respect to  FIGS. 7A-7D . 
     With reference to  FIG. 4 , when the key  105  is assembled, the dome  402  may communicate through the opening  404  to contact the base  303  when the dome  402  is collapsed (e.g., when the key  105  is actuated). In some cases, the base  303  includes electrical contacts  418 ,  420 , and the dome  402  is configured to contact or otherwise interact with the electrical contacts  418 ,  420  to facilitate detection of key actuations. For example, the retention features  406  (shown as arms in the present figures) may contact first electrical contacts  418  when the key  105  is assembled. When the dome  402  is collapsed, a different portion of the dome  402  (e.g., the actuation arm  423 ) may contact the second electrical contact  420 . The dome  402  may be formed from or otherwise include a conductive material (e.g., metal). Accordingly, when the dome  402  is collapsed and contacts both the first and second electrical contacts  418 ,  420 , the dome  402  may complete a signal path between the contacts that can be detected by a processing system associated with the key  105 . Other electrical switching mechanisms and configurations may also be used. For example, when collapsed, the dome  402  may force a first electrical contact into contact with a second electrical contact. In such cases, the dome  402  may not form a part of the signal path, but instead may act simply as an actuator to force one contact against another contact. 
     The dome support structure  314  (or switch housing, frame, or other dome support structure) may be coupled to the base  303  with an adhesive  422 . The adhesive  422  may have substantially the same footprint as the dome support structure  314 , though other configurations are also possible. The adhesive  422  may be positioned on either (or both) the dome support structure  314  and the base  303 . The adhesive  422  may be any appropriate adhesive, including curable liquid adhesives, adhesive layers or tapes, or the like. 
     In some embodiments, the dome support structure  314  is coupled to the base  303  using other mechanisms instead of or in addition to the adhesive  422 . For example, the dome support structure  314  may include pins, arms, clips, or other features that mechanically engage and/or retain the dome support structure  314  to the base. As one specific example, the dome support structure  314  may have pins (not shown) that extend through or into openings  424  in the base  303 . The pins may be deformed (e.g., via a heat staking operation) to retain the dome support structure  314  to the base  303 . 
     Regardless of whether or not the pins are configured to fix the dome support structure  314  to the base  303  (e.g., by heat staking), the pins may align the dome support structure  314  (and thus the entire switch assembly  206  and the keycap  204 ) with respect to the base  303 . For example, in some embodiments, the dome support structure  314  is fixedly retained to the base  303  by the adhesive  422  or another fastener, and the pins and openings  424  are used to aid in the alignment and placement of the dome support structure  314  on the base  303  during manufacturing and/or assembly of the keyboard. 
       FIGS. 5A-5D  show an exploded view of the key  105  at various stages of assembly.  FIG. 5A  illustrates components of the key  105  in a disassembled state.  FIG. 5B  illustrates an initial step of assembling the switch package  302 , namely, the dome  402  is placed in the opening  404  ( FIG. 4 ) of the dome  402 . The retention features  406  ( FIG. 4 ) of the dome  402  may engage with the dome support structure or frame  314  by overlapping and/or contacting the retention surfaces  408  ( FIG. 4 ). As described above, the retention features  406  and the retention surfaces  408  may retain the dome  402  in the dome support structure  314  in at least one direction (e.g., supporting the dome in an upward direction, as depicted in  FIG. 5B ). 
     After the dome  402  is placed in the dome support structure  314 , the cover member  316  is placed over the dome and is coupled to the dome support structure  314 , thus completing the switch package  302  as shown in  FIG. 5C . After the switch package  302  is assembled, it may be coupled to the butterfly hinge  304  to form the switch assembly  206 , as shown in  FIG. 5D . More particularly, the switch package  302  may be inserted into the opening of the butterfly hinge  304  (or the butterfly hinge  304  may be placed around the switch package  302 ) such that the pivot pins  414  (or other pivot members including posts, rods, protrusions, bumps, arms, or the like) of the butterfly hinge  304  are disposed in the retention channels  412  (or other pin retention features) of the dome support structure  314 . The retention channels  412  (or other pin retention features) and the pivot pins  414  may be configured such that when the butterfly hinge  304  and the switch package  302  are coupled as shown in  FIG. 5D , the butterfly hinge  304  is not secured to the switch package  302  in a direction towards the base  303 . More particularly, the retention channels  412  may have openings facing the base  303 , such that the pivot pins  414  can slide out of the retention channels  412  until the switch assembly  206  is placed on and/or coupled to the base  303 . Accordingly, an assembly head may hold both the butterfly hinge  304  and the switch package  302  together prior to being placed on the base  303 . 
     As shown in  FIG. 5D , the switch assembly  206  is assembled prior to any of its components being coupled to the base  303 . By preassembling the switch assembly  206 , the assembly of each individual key of a keyboard may be simplified, resulting in greater efficiencies and manufacturing yields. Indeed, preassembling the switch assembly  206  as described herein obviates the need to solder or otherwise electrically or mechanically couple a dome directly to the keyboard base. For example, as described herein, the process of coupling the switch assembly  206  to the base  303  results in the dome  402  being placed in electrical contact with electrical contacts (e.g., the electrical contacts  418 ), and being physically retained in position by the dome support structure  314  and its mechanical coupling to the base  303 . 
     The assembly sequence in  FIGS. 5A-5D  may generally correspond to the order of operations of assembly of the key  105 , though the exact spatial relationships shown in  FIGS. 5A-5D  are not necessarily representative of an actual assembly process. For example, the switch package  302  may be assembled at one facility or machine, and then assembled into a keyboard at a different facility or machine. Moreover, other steps may be included between those shown and described herein, and other components may be included in addition to those shown, such as the adhesive  422  ( FIG. 4 ). 
       FIG. 6  shows a cross-sectional view of the switch assembly  206 , viewed along line  6 - 6  in  FIG. 3 .  FIG. 6  shows the switch assembly  206  coupled to the base  303 , illustrating how the pivot pins  414  (or other pivot members) are captured in the retention channels  412  by a surface of the base  303 . For example, the retention channels  412  are defined by substantially u-shaped walls that have an opening or a gap  602  at one end (e.g., such that the opening faces the base  303 ). The pivot pins  414  can be introduced into the retention channels  412  via the opening  602  prior to the switch assembly  206  being coupled to the base  303 . Once the switch assembly  206  is positioned on the base  303 , a surface of the base (or an interstitial layer or component) captures the pivot pins  414  between the walls of the channels  412  and the surface of the base  303  (or any other object that is adjacent the switch assembly  206  when a keyboard is assembled). In this way, the butterfly hinge  304  ( FIG. 3 ) is retained to the base  303 . 
       FIG. 7A  shows the dome support structure  314  coupled to the base  303  to illustrate the structure and function of the optical elements of the dome support structure  314 , including the light guide  702 , a light-directing feature  706 , reflection features  708 , and an illumination feature  710  ( FIG. 7C ). Features such as the light guide  702 , the light-directing feature  706 , the reflection features  708 , and the illumination feature  710  are not shown in other figures for clarity and/or simplicity. It will be understood that these (or other features) may be present in the dome support structure  314  or any embodiment of a dome support structure, switch housing, frame, or the like, regardless of whether it appears in any particular figure. 
     The light guide  702  may at least partially surround the opening  404  ( FIG. 4 ) of the dome support structure  314 , and thus may at least partially surround the dome  402  ( FIG. 4 ) positioned in the opening. The dome support structure  314  may be positioned on the base  303  such that the light source  312  is proximate the light input surface  416 . The light input surface  416  is optically coupled with the light guide  702 . Thus, light from the light source  312  enters the dome support structure  314  through the light input surface  416 , and is transmitted into the light guide  702 , as illustrated by the arrows  704  ( FIG. 7B ). 
     The light guide  702  may perform several functions. For example, it may generally contain light from the light source within the light guide  702 , rather than allowing it to freely distribute throughout the dome support structure  314 . This may result in a greater proportion of the light from the light source  312  being available to be redirected to a keycap (e.g., to illuminate a glyph or other transparent or translucent portion  315  in the keycap  204 ,  FIG. 3 ) or other illumination target. Second, the light guide  702  redirects light from within the light guide  702  towards the keycap or other illumination target. For example, the light guide  702  may include lenses, ridges, or other optical features that allow light to exit the light guide  702  in a desired direction. More particularly,  FIG. 7B  shows a side view of the dome support structure  314 , illustrating how light may be redirected through a top surface of the dome support structure  314 , and thus towards a keycap or other component positioned above the dome support structure. 
     The dome support structure  314  may include a light-directing feature  706  that is operative to direct light from the light emitting element around the light guide. The light-directing feature  706  may be positioned within the light guide  702  and/or on an outer surface of the light guide  702  near or otherwise adjacent the light source  312 . As shown, the light-directing feature  706  may reflect light down the right side of the light guide  702  and the left side of the light guide  702  in order to increase the uniformity of light throughout the light guide  702 . The light-directing feature  706  may include one or more structures that may be used to reflect or direct light. In one non-limiting example, the light-directing feature includes one or more Fresnel lenses. Although Fresnel lenses are specifically mentioned, other lenses and/or light-directing features or surfaces may be used. For example, in some embodiments, the light-directing feature  706  can be implemented as a chamfer or notch formed in an inner sidewall of the light guide  702 . In other embodiments, the light-directing feature  706  is a non-flat surface such as a convex surface, a concave surface, or a domed surface. In some other non-limiting examples, the light-directing feature  706  can also be coated with a reflective coating or material such as a metalized ink. 
     The dome support structure  314  may also include one or more one or more reflection features  708 . The reflection features  708  may be implemented as a through-hole, a laser etched or routed channel, an insert molded reflector, or the like. The reflection features  708  may be positioned adjacent to the light guide  702  and oriented to direct light (via internal reflection) within the body of the light guide  702 . More specifically, the reflection features  708  may be implemented as apertures (filled or open) through the body of the dome support structure  314 . In this manner, the reflection features  708  introduce a refractive index mismatch between the material of the body of the dome support structure  314  and air within the aperture, thereby increasing the amount of light that is transmitted through the light guide  702  and decreasing the amount of light that escapes the light guide  702  in undesired directions (e.g., through a side of the dome support structure  314 ). Accordingly, as light from the light source  312  hits the reflection features  708 , the refractive index of the reflection features  708  causes light to be reflected into the light guide  702 . Although two reflection features  708  are shown, the dome support structure  314  may include any number of reflection features  708  positioned at various locations around the light guide  702 . 
     With reference to  FIG. 7C , which is a partial cross-sectional view of the dome support structure  314  viewed along line  7 C- 7 C in  FIG. 7A , the dome support structure  314  may also include an illumination feature (or illumination features)  710  operative to direct light out of the light guide  702  and towards a keycap  204  (or other component or area to be illuminated). For example, the illumination feature  710  may include one or more prisms such as, for example, first prisms  712  and second prisms  714  that are different than the first prisms  712  in one or both of configuration and function. In some embodiments, the dimensions, shapes, sizes, and/or number of the first prisms  712  and the second prisms  714  may vary. For example, the first prisms  712  may be rounded or scalloped while the second prisms  714  have a triangular shape, a concave portion, and so on. The first and second prisms  712 ,  714  may be operative to interact with light in a different manner. For example, the first prisms  712  may be used to direct light in a first direction while the second prisms  714  may be used to direct light in a second direction. 
     More specifically, the first prisms  712  may be used to direct light to one more glyphs on a keycap while the second prisms  714  may be used to reflect light internally through the light guide  702 . In some implementations, the illumination feature  710  may be placed on specific, discrete areas of the light guide  702  that are less than an entire surface of the light guide  702 . In other implementations, such as that shown in  FIG. 7A , the illumination feature  710  may cover an entire surface of the light guide  702 . 
     The light guide  702  may be a different material than other portions of the dome support structure  314 . For example, the light guide  702  may be a transparent or translucent material that is coupled to the dome support structure  314  (e.g., via co-molding, insert-molding, or multi-shot injection molding, or any other appropriate technique). More particularly, the dome support structure  314  may include a channel  718  into which a material for the light guide  702  is positioned. With reference to  FIG. 7D , which shows an expanded view of area  716  in  FIG. 7A , the channel  718  may be defined by an inner sidewall  720  and an outer sidewall  722 . The sidewalls  720 ,  722  may form or include prisms or scallops that are configured to reflect light internally within the light guide  702 . The prismatic sidewalls  720 ,  722  may decrease the amount of light lost through the sidewalls of the light guide  702  (relative to a smooth sidewall, for example), and/or guide the light through the light guide  702 . The prisms  720 ,  722  may be used instead of or in addition to the reflection features  708  described above to direct light through the light guide. 
     Alternatively, the light guide  702  may be the same material as other portions of the dome support structure  314 . In such cases, the dome support structure  314  may be formed from or otherwise include a transparent or translucent material, and the light guide  702  may be defined and/or differentiated from the surrounding regions of the dome support structure  314  by a distinct structure, shape, or other property. For example, openings or channels extending through the thickness of the dome support structure  314  (such as the reflection features  708 ) may define walls of the light guide  702 . 
     In some cases, the dome support structure  314  and the light guide  702  are implemented as a single monolithic structure formed entirely of a transparent or translucent material. In such cases, features such as the reflection features  708 , the illumination features  710 , and the light-directing feature  706  may be formed in any suitable manner. For example, the dome support structure  314  may include any of these or other features in an as-molded state, or they may be machined, cut, drilled, melted, or otherwise formed into the body of the dome support structure  314 . Suitable materials for a dome support structure  314  with a light guide  702  include, without limitation, polycarbonate, polystyrene, polymethlamethacrylate, and glass. Where the dome support structure  314  is transparent, translucent, or otherwise includes a light guide, it may be referred to as an optical dome support structure or an optical switch housing. 
       FIGS. 8A-8B  show a cross-sectional view of the switch assembly  206 , viewed along line  8 - 8  in  FIG. 3 .  FIG. 8A  shows the switch assembly  206  when the key  105  is in an unactuated or undepressed state, and  FIG. 8B  shows the switch assembly  206  when the key  105  is in an actuated or depressed state. For clarity, some components or portions of the switch assembly  206  are not shown in  FIGS. 8A-8B . 
       FIGS. 8A-8B  show how the dome  402  is retained to the dome support structure  314  when the cover member  316  is placed over the dome  402  and coupled to the dome support structure  314 . In particular, the retention features  406  of the dome  402  overlap the retention surfaces  408  of the dome support structure  314 , thereby retaining the dome  402  in an upward direction (as depicted in the figures). Similarly, the cover member  316  covers the dome  402  and is attached to the dome support structure  314 , thereby retaining the dome  402  in a downward direction (as depicted in the figures). As described, this configuration allows the switch assembly  206  to be moved and manipulated as a single, self-contained unit prior to being coupled to a base  303 . 
     The switch assembly  206  may be configured so that the process of coupling the switch assembly  206  to the base  303  preloads or biases the dome  402  against the base  303 , and more particularly, against the electrical contacts  418 . For example, as shown in  FIGS. 8A-8B , the retention features  406  of the dome  402  are not in contact with the retention surfaces  408  of the dome support structure  314  when the switch assembly  206  is positioned on the base  303 . More particularly, the geometry of the dome  402  and the dome support structure  314  is such that the dome  402  may be forced upwards against the cover member  316  when the switch assembly  206  is placed on the base  303 . The cover member  316  imparts a responsive force on the dome  402  in a downward direction, thus biasing the retention features  406  against the electrical contact  418  to maintain a consistent electrical connection between the dome  402  and the electrical contact  418 . 
     As noted above, the dome  402  may include a protruding member that extends into an interior volume of the dome. As shown in  FIGS. 8A-8B , the protruding member is an actuation arm  423 , though other types of protruding members may be used, including indentations, springs, foam or elastomeric pads, or the like. When the key  105  is actuated and the dome  402  is collapsed, as shown in  FIG. 8B , the actuation arm  423  may contact the electrical contact  420 , thus completing an electrical path from the electrical contact  418  to the electrical contact  420 . 
     The actuation arm  423  may deflect when the dome  402  is collapsed. The deflection of the actuation arm  423  may facilitate a positive electrical contact with the electrical contact  420  when the dome  402  is collapsed. The deflection of the actuation arm  423  may also produce a desirable tactile response or sensation to a user. For example, the deflection may prevent or reduce the feeling of the key abruptly bottoming out when it is actuated by a user. Moreover, the deflection of the actuation arm  423  may reduce the stresses on the dome  402  that may be caused by the repeated collapse of the dome  402  during use, for example, by reducing the amount or extent that the dome  402  buckles when the dome  402  is collapsed. 
     The actuation arm  423  may also decouple the design considerations relating to the stroke length of the dome  402  from the considerations relating to tactile feel. For example, a larger (e.g., taller) dome may provide a more desirable tactile response than a smaller (e.g., shorter) dome, but a shorter stroke length may be desired, which may be achieved in some cases with a smaller dome. By including the actuation arm  423 , the stroke length of the dome  402  may be reduced while maintaining a larger dome that provides the desired tactile response. 
     The dome  402  may also include travel limiting features  802  that extend from the concave inner surface into the interior volume of the dome  402 . The travel limiting features  802  may be configured to define a maximum travel of the key  105 , as well as to limit an amount of travel or an amount of deflection of the actuation arm  423  when the dome  402  is collapsed. The travel limiting features  802  may be any shape, material, or component that defines a maximum travel distance of the dome  402 . For example, as shown in the instant figures, the travel limiting features  802  are indentations in the dome  402 . In other embodiments, they may be pads (e.g., plastic or metal pads) that are coupled to the interior surface of the dome  402  (e.g., via adhesive, welding, or any other bonding technique). Travel limiting features  802  may be coupled to or formed on the base  303 , or any other component that is between the base  303  and the dome  402 . For example, a layer such as a membrane layer, flexible circuit board, or the like (not shown) may be positioned between the base  303  and the switch assembly  206 , and a travel limiting  802  feature may extend from the layer to define a maximum travel of the dome  402  and/or a maximum deflection of the actuation arm  423 . 
       FIG. 9  shows the dome  402 . The dome  402  includes a dome portion  902 , an actuation arm  423  (or another protruding member), an array of suspension arms  904 , and one or more travel limiting features  802 . As shown and described herein, the dome  402  is a collapsible dome. More particularly, the collapsible dome  402  is configured to collapse or otherwise deform in response to an actuation force to provide mechanical and electrical functionality to a key or other input mechanism. 
     The dome portion  902  may have a convex-concave shape, with the concave surface of the dome portion  902  defining an interior volume. The dome portion  902  may be configured to collapse in response to an actuation force, as shown and described with respect to  FIGS. 8A-8B . The particular size, shape, and materials of the dome portion  902  may be selected so that the collapsible dome  402  (or other dome) provides a desired force response, as characterized by a force versus deflection (e.g., travel) curve. An example force versus deflection curve for a key with the collapsible dome  402  is described herein. 
     The suspension arms  904  extend from an outer edge of the dome portion  902  and support the dome portion  902  away from the base  303  when the collapsible dome  402  is unactuated and/or uncollapsed. The suspension arms  904  may be configured to collapse or deform when the dome is actuated. For example, the suspension arms  904  may be configured to collapse or deform in response to a lower force than the dome portion  902 . More particularly, an actuation force applied to a key may first cause the suspension arms  904  to collapse or deform, and thereafter may cause the dome portion  902  to collapse or deform. Thus, the suspension arms  904  may contribute to the particular force response provided by the collapsible dome  402 . 
     The suspension arms  904  may also include the retention features  406 . For example, a distal end of a suspension arm  904  may define a retention feature  406  that engages the dome support structure  314  to retain the collapsible dome  402  to the dome support structure  314  in at least one direction. While the instant figures illustrate suspension arms  904  that include retention features  406 , and thus provide both retention and suspension functions, these functions may be provided by different components. For example, a dome may include a pair of suspension arms and a separate pair of retention features. Other configurations and combinations are also contemplated. 
     As described above, the collapsible dome  402  includes an actuation arm  423  that protrudes or extends into the interior volume, and may be configured to contact and deflect against the base  303  when the key  105  is actuated. The actuation arm  423  may be formed from or coupled to the collapsible dome  402  in any appropriate way. In the illustrated example, the actuation arm  423  is formed by removing material from the dome portion to define the actuation arm  423  (e.g., by laser or plasma cutting, stamping, or the like) while leaving the actuation arm  423  connected to the dome portion  902  via a base portion  906 . In such cases, the actuation arm  423  and the dome portion  902  are formed from a single piece of material and are a unitary component. 
     The travel limiting features  802  of the collapsible dome  402  are indentations formed into the dome portion  902  that protrude or extend from the concave surface into the interior volume of the dome portion  902 . The travel limiting features  802  may be positioned in any appropriate location along the dome portion  902 . In the illustrated example, the travel limiting features  802  are positioned proximate the base portion  906 . By positioning the travel limiting features  802  on the dome portion  902  and proximate the base portion  906 , as shown, the maximum deflection of the actuation arm  423  and/or the maximum travel of the collapsible dome  402  during actuation of the key  105  can be carefully established. More particularly, positioning the travel limiting features  802  further away from the base portion  906  may be less effective for establishing a maximum deflection of the actuation arm  423  and/or maximum travel of the collapsible dome  402 . 
       FIGS. 10A-10C  show cross-sectional views of the collapsible dome  402 , viewed along line  10 - 10  in  FIG. 8 , showing the collapsible dome  402  in an unactuated or uncollapsed state ( FIG. 10A ), a partially collapsed state ( FIG. 10B ), and an actuated or fully collapsed state ( FIG. 10C ). While not shown in  FIG. 9 , the base  303  is included in  FIGS. 10A-10C  for clarity. 
     With respect to  FIG. 10A , the suspension arms  904  of the collapsible dome  402  each include a collapsible portion  1002  at a proximate end of the suspension arm  904  (e.g., proximate the edge of the dome portion  902 ), a curved portion  1004  that contacts the electrical contact  418 , and an engagement portion  1006  at a distal end of the suspension arm  904 . As described herein, the collapsible portion  1002  may be configured to deform or collapse in response to an actuation force on the key  105 . 
     The collapsible portions  1002  of the suspension arms  904  depicted in the instant figures extend from the outer edge of the dome portion  902  along tangent lines of the dome portion  902 . In other words, the collapsible portion  1002  of a suspension arm  904  is an extension of the shape, contour, and/or profile of the dome portion  902 . In other example domes, the collapsible portions  1002  may deviate from a tangent line of the dome portion  902 . For example, the collapsible portions  1002  may extend substantially horizontally from the outer edge of the dome portion  902 . 
     The engagement portions  1006  of the suspension arms  904  may correspond to the retention features  406 , described above. In particular, the engagement portion  1006  may engage a retention surface  408  of the dome support structure  314  when the collapsible dome  402  is assembled with the dome support structure  314 . 
     The progression from  FIG. 10A  to  FIG. 10C  illustrates how the collapsible dome  402  may respond to application of an actuation force on the key  105 . In particular,  FIG. 10A  represents the collapsible dome  402  prior to any actuation force being applied to the keycap  204 . As an actuation force is applied to a keycap  204 , the suspension arms  904  begin to deform. As the actuation force continues to increase, the suspension arms  904  eventually completely collapse, corresponding to a first deflection distance of the collapsible dome  402 . In some cases, the suspension arms  904  are completely collapsed when they are substantially flat against the base  303 , though other configurations are also possible. 
     As the actuation force continues to increase after the suspension arms  904  are completely collapsed, the dome portion  902  begins to deform slightly until an inflection point is reached, at which point the dome rapidly collapses against the base  303 , corresponding to a second deflection distance of the collapsible dome  402  that is greater than the first deflection distance. The inflection point and subsequent rapid collapse of the dome portion  902  may generate an audible and/or tactile output for a user, such as a characteristic “click” of a computer key. Once the dome portion  902  is completely collapsed, the actuation arm  423  (or another portion of the collapsible dome  402 ) may contact the electrical contact  420 , thereby causing a key actuation to be detected by an electronic device. 
       FIG. 11  is a force versus deflection (e.g., travel) curve  1100  characterizing the force response of the key  105  ( FIG. 1 ) with reference to the states of the collapsible dome  402  shown in  FIGS. 10A-10C . In particular, the key  105  of  FIG. 1  may include the collapsible dome  402  described with respect to  FIGS. 10A-10C , and certain points and features of the force versus deflection curve  1100  may be understood with reference to  FIGS. 10A-10C . 
     As an actuation force causes the keycap  204  of the key  105  to move and the collapsible dome  402  begins to deform, the force response of the key  105  increases from point  1102  until an inflection point  1106  is reached, at which point the collapsible dome  402  collapses, as described above. Because the collapsible dome  402  includes both suspension arms  904  and a dome portion  902 , the portion of the curve  1100  between points  1102  and  1104  may correspond primarily or exclusively to deformation of the suspension arms  904 , and the portion of the curve  1100  between points  1104  and  1106  may correspond primarily or exclusively to deformation of the dome portion  902 . Of course, the deformations of the suspension arms  904  and the dome portion  902  may blend together. For example, the deflection of the dome portion  902  and the suspension arms  904  may overlap across all or part of the curve  1100  between points  1102  and  1106 . 
     After the inflection point  1106 , the resistive force of the collapsible dome  402  decreases until it reaches the operating point  1108 , which may correspond to the actuation arm  423  (or any other portion of the collapsible dome  402 ) contacting the base  303 . Under normal operating conditions and forces, the operating point  1108  may be at or near a maximum travel of the key  105 , and thus may correspond to a point at which the collapsible dome  402  is fully or substantially fully collapsed and the travel limiting features  802  ( FIG. 8 ) are in contact with the base  303 . 
     The key  105 , or other input mechanism or structure that includes the collapsible dome  402  (or other dome), may be configured such that the collapsible dome  402  contacts the electrical contact  420 , and thus results in a detectable key actuation event, at any appropriate point along the force/deflection curve  1100 . For example, the collapsible dome  402  my contact the electrical contact  420  at or near the inflection point  1106 . As another example, the collapsible dome  402  my contact the electrical contact  420  at or near the operating point  1108 . As yet another example, the collapsible dome  402  my contact the electrical contact  420  between the inflection point  1106  and the operating point  1108 . 
     Certain physical characteristics of the dome  402 , including the material, dimensions, shape, and the like, may determine the particular force versus deflection curve exhibited by the key  105 . Moreover, the relative sizes, thicknesses, curvatures, shapes, materials, and/or other properties of the dome portion  902 , the suspension arms  904 , and/or the actuation arm  423  may determine the force versus deflection curve. Moreover, the different portions or components of a dome  402  may affect different aspects of the force versus deflection curve. For example, increasing the length of the suspension arms  904  (and in particular a length of the collapsible portions  1002  of the suspension arms  904 ) may increase the stroke length of the key  105  without substantially changing the force at the inflection point  1106 . As another example, changing the angle of the suspension arms  904  with respect to a tangent line extending from the outer edge of the dome portion  902  may change the stroke length of the key  105  without substantially changing the force at the inflection point  1106 . Other changes or modifications to the collapsible dome  402  shown and described herein are also contemplated. 
     In  FIG. 11 , the point  1102  (e.g., where the curve  1100  begins) may indicate a point at which a non-zero force results in zero displacement of the key  105 . That is, the curve  1100  does not necessarily show the force response of the key  105  from a point of zero force, but rather from a point where displacement of the key  105  begins. In some cases, the force response of the key  105  from the origin (e.g., a point of zero force and zero displacement) to point  1102  may be characterized by a substantially vertical path, reflecting a key  105  for which no displacement takes place until a threshold force is reached. In other cases, the force response of the key  105  from the origin may follow another profile, such as a line having a slope of less than infinity (e.g., a non-vertical line), or it may follow a nonlinear path. Moreover, portions of the curve  1100  that are shown as linear or substantially linear may instead be nonlinear, and segments that are shown as nonlinear may be linear or may include linear portions. For example, the linear portion extending from point  1102  towards point  1104  may instead follow or include a curved path. Indeed, the curve  1100  is merely one example force versus deflection curve, and the key  105  may be characterized by other curves representing different force responses. 
       FIG. 12  shows a butterfly hinge  304  that includes a first wing  1202  coupled to a second wing  1204  via a coupling mechanism  1206 . The butterfly hinge  304  may be an embodiment of the butterfly hinge  304 , described above. As shown, the coupling mechanism  1206  is a living hinge, though other coupling mechanisms  1206  may also be used, including a gear hinge or other flexible linking mechanism. As used herein, a living hinge may be a flexible material or combination of materials that physically attaches the two wings together. A gear hinge is a coupling mechanism built into the wings themselves that allows for a gear-like interaction between the wings. 
     The coupling mechanism  1206  mechanically links the first and second wings  1202 ,  1204  such that a force applied to one wing will result in the movement of both wings. This may provide consistent actuation of a key regardless of where on the keycap an actuation force is applied. For example, if a user presses on a corner of the keycap of the key  105  ( FIG. 1 ), the actuation force may be unevenly distributed between the first and second wings  1202 ,  1204 . Because the wings  1202 ,  1204  are coupled via the coupling mechanism  1206 , the movement of the wings may be substantially synchronized despite the difference in forces applied thereto. This may cause the keycap to remain substantially parallel to its rest position throughout the keystroke, which in turn allows the keycap to interact with a dome of the key  105  evenly and consistently no matter where on the keycap the actuation force is applied. 
     The wings  1202 ,  1204  may include the pivot pins  414  or other pivot members, as well as keycap coupling members  1208 . The keycap coupling members  1208  may engage retention features (e.g., retention clips) on a corresponding keycap  204 . The pivot pins  414  and the keycap coupling members  1208  may be integrally molded with the wings  1202 ,  1204 . For example, the wings  1202 ,  1204  may be each formed as a single, monolithic component via an injection molding process (or any other appropriate manufacturing technique). Where a mold is used to form the wings  1202 ,  1204 , the mold&#39;s parting lines may be positioned away from the pivot pins  414  and/or the keycap coupling members  1208  such that flashing or excess material is not formed on the pivot pins  414  or the keycap coupling members  1208 . This may help prevent binding, scraping, or other negative interactions between the pins  414  and the coupling members  1208  and the corresponding surfaces or components that they engage with when a key is actuated. 
     The butterfly hinge  304  may be manufactured using a double-shot process, where the first shot forms the wings  1202 ,  1204 , and the second shot forms the living hinge  1206 . As described herein, the wings  1202 ,  1204  may include interlocking structures and/or shapes, including pins, channels, protrusions, or the like, that engage the living hinge  1206 . When the second shot is applied, the material of the second shot flows into or around the interlocking structures. Once cured or hardened, the living hinge  1206  forms complementary structures (e.g., channels, protrusions, receptacles, etc.) that retain the living hinge material to the wings  1202 ,  1204 . 
       FIGS. 13-24  illustrate example wings and living hinges for use in a butterfly hinge, such as the butterfly hinge  304 . The wings and living hinges shown and described in these figures may be formed using a double-shot process (or any other suitable process or technique), in which the material of the living hinges is caused to engage interlocking structures on the wings. For clarity, some components of the butterfly hinges in  FIGS. 13-24  are shown in phantom lines. Also, for ease of reference, the butterfly hinges and components thereof in  FIGS. 13-24  may be labeled with unique reference numbers. However, it will be understood that these figures relate to example embodiments of the butterfly hinge  304 , and the components shown in and described with respect to these figures may provide the same or similar functionality of the butterfly hinge  304  described above, and may be in some respects identical to the butterfly hinge  304  described above. Moreover, in these figures, portions of the butterfly hinges and/or living hinges are shown in broken lines to show details of internal components. 
       FIG. 13  shows a portion of a butterfly hinge  1300  with wings  1302 ,  1304  that include protrusions  1307  with which a living hinge  1306  engages to retain the living hinge  1306  to the wings  1302 ,  1304 . In particular, during manufacturing, the material of the living hinge  1306  flows around the protrusions  1307  during the second shot to form complementary engagement structures within the living hinge  1306 . 
     The living hinge  1306  may have coupling portions  1308  and a joining portion  1310 . The joining portion  1310  may be thinner than the coupling portions  1308  to facilitate flexing of the living hinge  1306  during actuation of a key. The coupling portions  1308  may engage the first and second wings  1302 ,  1304  to retain the living hinge  1306  to the wings  1302 ,  1304 . 
       FIG. 14  shows a butterfly hinge  1400  with wings  1402 ,  1404  that include channels  1408 . The material of a living hinge  1406  flows or is forced into the channels  1408  during the second shot to form complementary structures in the living hinge  1406  that retain the living hinge  1406  to the wings  1402 ,  1404 . The living hinge  1406  includes a joining portion  1410  that is substantially the same size as the opening in the channels  1408 . That is, apart from the portions of the living hinge that are in the channels  1408 , the living hinge  1406  has a substantially constant thickness. The thickness of the joining portion  1410  of the living hinge may be selected based on various factors, including a desired stiffness or flexibility, a material used, a desired durability, manufacturing concerns, and the like. 
       FIG. 15  shows a butterfly hinge  1500  where the wings  1502 ,  1504  include channels  1508 , similar to the channels  1408  in  FIG. 14 . A portion of a living hinge  1506  engages the channels  1508  in a similar manner to retain the living hinge  1506  to the wings  1502 ,  1504 . Unlike the living hinge  1406 , a joining portion  1510  of the living hinge  1506  is thicker than the opening in the channels  1508 . In some embodiments, such as that shown in  FIG. 15 , the joining portion  1510  forms a substantially continuous surface (e.g., with no gaps, ledges, or other discontinuities) with the surfaces of the wings  1502 ,  1504 . 
       FIG. 16  shows a butterfly hinge  1600  where the wings  1602 ,  1604  include cutouts  1608 . The material of a living hinge  1606  flows or is forced into the cutouts  1608  during a second shot to form complementary structures in the living hinge  1606  that retain the living hinge  1606  to the wings  1602 ,  1604 . The cutouts may extend generally perpendicular to an axis about which the living hinge  1606  pivots (e.g., perpendicular to a longitudinal axis of a joining portion  1610 ). 
       FIG. 17  shows a butterfly hinge  1700  where the wings  1702 ,  1704  include tongues  1708 . The tongues  1708  may include openings  1710 , such as blind holes or through-holes. The material of a living hinge  1706  flows or is forced into the openings  1710  during the second shot to form complementary structures in the living hinge  1706  that retain the living hinge  1706  to the wings  1702 ,  1704 . In some cases, the tongues  1708  may be substantially featureless (e.g., having substantially continuous surfaces with no holes or other engagement features), and the living hinge  1706  may be adhered or bonded to the tongues  1708 . For example, the material of the living hinge  1706  may act as an adhesive that secures the living hinge  1706  structure to the tongues  1708 . 
       FIG. 18  shows a butterfly hinge  1800  where the wings  1802 ,  1804  include tongues  1808 . Similar to the tongues  1708  in  FIG. 17 , the tongues  1808  may include openings  1810 . The material of a living hinge  1806  flows or is forced into the openings  1810  during the second shot to form complementary structures in the living hinge  1806  that retain the living hinge  1806  to the wings  1802 ,  1804 . The openings  1810  may be positioned near the bases of the tongues  1808  (e.g., where the tongues  1808  and the wings  1802 ,  1804  join, which may be a substantially perpendicular interface). At least a portion of one or more of the openings may be defined by a surface of the adjacent wing. In such cases, the point of engagement between a tongue  1808  and the living hinge  1806  may be closer to the base of the tongue  1808  than the configuration shown in  FIG. 17 . This may eliminate or reduce overhanging portions of the living hinge near the joint between the living hinge and the wings that may delaminate or decouple during use. 
       FIG. 19  shows a butterfly hinge  1900  where the wings  1902 ,  1904  include protrusions  1908  and openings  1910 . The material of a living hinge  1906  flows or is forced around the protrusions  1908  and into the openings  1910  during the second shot to form complementary structures in the living hinge  1906  that retain the living hinge  1906  to the wings  1902 ,  1904 . As shown, the living hinge  1906  does not fully cover the protrusions  1908 , such that surfaces of the protrusions  1908  and an external surface of the living hinge  1906  form a substantially continuous surface. In other embodiments, the protrusions  1908  may be fully encapsulated or covered by the living hinge  1906 . 
     The wings and the living hinges in the foregoing examples may be formed from or include any appropriate materials. For example, the wings may be formed from polyester, polyamide, glass filled polyamide, nylon, polycarbonate, acrylonitrile butadiene styrene, zinc, aluminum, or any other appropriate material, including metals, polymers, ceramics, etc. The living hinges may be formed from silicone, polyurethane, natural rubber, latex, or any other appropriate polymer or other material. Where the wings and the living hinges are formed from polymers, the polymers may adhere to one another (e.g., they may melt or weld together). In such cases, physical interlocking structures may be omitted from the wings. Alternatively, physical interlocking structures may be used to enhance the security of the coupling between the living hinges and the wings. Where the wings and the living hinge are not both polymers, such as where the wings are formed from a metal, the materials may not adhere significantly. Accordingly, physical interlocking structures may be used to ensure a secure coupling between dissimilar materials. For example, the butterfly hinge  1900  of  FIG. 19  that includes both openings  1910  and protrusions  1908  may be suited for use with metal wings and a polymer living hinge material. 
       FIGS. 20A-24  illustrate butterfly hinges that may be manufactured using a double-shot injection molding process. Butterfly hinges in accordance with the instant disclosure (such as those described with reference to  FIGS. 20A-24 ) may be manufactured using other processes as well, including co- or insert-molding. Such techniques may be used, for example, where the living hinge is formed from a material that is not suited for injection molding, including fabric, metal, and the like. In these figures, portions of the butterfly hinges are shown in broken lines to show details of internal components. 
       FIG. 20A  shows an example butterfly hinge  2000  that may be produced by insert-molding wings  2002 ,  2004  around an insert  2006 . The insert  2006  may include hinge portions  2008  and web portions  2010 . The web portions  2010  may be used for handling and securing the insert  2006  during manufacturing of the butterfly hinge  2000 . As shown in  FIG. 20A , the web portions  2010  are still coupled to the hinge portions  2008 , and thus illustrates the butterfly hinge  2000  in an intermediate stage of manufacture. 
     A method of manufacturing the butterfly hinge  2000  may include placing the insert  2006  in a mold, and thereafter injecting material into the mold to form the wings  2002 ,  2004  and encapsulate at least part of the insert  2006  (e.g., the hinge portion  2008 ) within the wings  2002 ,  2004 . The butterfly hinge  2000  may then be ejected from the mold and the web portions  2010  of the insert may be removed from the butterfly hinge  2000  (and thus the hinge portion  2008 ) by laser, plasma, or water-jet cutting, or any other separating operation. The hinge portion  2008  remains at least partially encapsulated in the wings  2002 ,  2004  and acts as a living hinge for the butterfly hinge  2000 . 
     The insert  2006 , and in particular the hinge portion  2008  of the insert  2006 , may include openings  2012  or other features that engage with the material of the wings  2002 ,  2004  to secure the hinge portion  2008  to the wings  2002 ,  2004 . For example, when material is injected into the mold, the material flows through the openings, thus forming an interlocking shape that retains the hinge portion  2008  to the wings  2002 ,  2004 . The insert  2006  may be formed from or include any appropriate material, including metals (e.g., stainless steel), composites, polymers (e.g., Vectran, para-aramid fibers, polyether ether ketone, polyimide, nylon, or fabrics formed from such materials), or any other appropriate material. 
       FIG. 20B  shows a plurality of butterfly hinges  2000  coupled to an insert  2014  that supports multiple butterfly hinges  2000 . This may increase the manufacturing speed and/or efficiency when producing multiple butterfly hinges  2000 , as the butterfly hinges  2000  may be manufactured in a continuous or step-wise fashion, and can reduce setup time and other material handling costs as compared to manufacturing each butterfly hinge  2000  separately. The butterfly hinges  2000  may be separated from the insert  2014  at any appropriate time, such as immediately prior to being assembled in a keyboard. For example, strips or rolls of butterfly hinges  2000  still coupled to the insert  2014  may be fed into or supplied to a pick-and-place, tape-and-reel, or other manufacturing machine or system, which then separates individual butterfly hinges  2000  as they are needed and optionally assembles the butterfly hinges  2000  to form switch assemblies that are then coupled to a keyboard base plate. 
       FIG. 21  shows an example butterfly hinge  2100  that may be produced by insert molding wings  2102 ,  2104  around an insert  2106 . The insert  2106 , which may be formed from fabric, metal, or any other appropriate material, may include hinge portions  2108  and web portions  2110 . The web portions  2110  may be used for handling and securing the insert  2106  during manufacturing of the butterfly hinge  2100 . As shown in  FIG. 21 , the web portions  2110  are still coupled to the hinge portions  2108 , and thus illustrates the butterfly hinge  2100  in an intermediate stage of manufacture. The web portions  2110  may be removed before the butterfly hinge  2100  is incorporated into a keyboard, as described above. 
       FIGS. 20A-21  illustrate butterfly hinges where the insert forms the living hinge.  FIGS. 22-24  show butterfly hinges where material is molded over and/or around an insert that forms an internal frame or structure for the wings, and the wing material forms the living hinge. For example,  FIG. 22  shows a butterfly hinge  2200  that may be produced by insert molding wings  2202 ,  2204  around an insert  2206 . The insert  2206  may include frame portions  2208 ,  2209  and web portions  2210 . The frame portions  2208 ,  2209  may form an internal frame or support structure for the wings  2202 ,  2204 . The wings  2202 ,  2204  form a unitary, monolithic structure that includes living hinge portions  2212  joining the first wing  2202  to the second wing  2204 . Once the web portions  2210  are removed from the insert  2206 , the frame portions  2208 ,  2209  may not contact one another (e.g., they do not extend through the living hinge portion  2212 ). 
       FIG. 23  shows a butterfly hinge  2300  that may be produced by insert molding wings  2302 ,  2304  around an insert  2306 . The insert  2306  may include frame portions  2308 ,  2309 , and web portions  2310 . The frame portions  2308 ,  2309  may be similar in shape and function to the frame portions  2208 ,  2209  ( FIG. 22 ), but the web potions  2310  may have a different configuration that the web portions  2210 . For example, instead of substantially surrounding the butterfly hinge as shown in  FIG. 22 , the web portions  2310  extend through a central region of the butterfly hinge  2300 . 
     In  FIGS. 22-23 , external features of the butterfly hinges  2200 ,  2300  are formed from the wing material. For example, pins  2214 ,  2314  ( FIGS. 22, 23 , respectively) may be formed from the wing material during the molding of the wings. In some cases, some or all of the pins (or other external features of the butterfly hinges) may be part of or extend from the insert around which the wings are molded. For example,  FIG. 24  shows a butterfly hinge  2400  that may be produced by insert molding wings  2402 ,  2404  around an insert  2406 , where pins  2408  extend beyond the external surface of the wings  2402 ,  2404 . In other functional and/or structural respects, the butterfly hinge  2400  may be the same as the butterfly hinge  2300  ( FIG. 23 ). 
     The butterfly hinges described herein (e.g., the butterfly hinge  304 ) are configured to movably support a keycap (e.g., a keycap  204 ) relative to a keyboard base (e.g., the base plate  208 ).  FIG. 25  illustrates the key  105  of the keyboard  102  ( FIG. 1 ), which includes the keycap  204  positioned in an opening in a web  202  and a butterfly hinge  304  (not visible in  FIG. 25 ) movably supporting the keycap  204  relative to the keyboard base. When the key  105  is actuated, the keycap  204  moves towards the keyboard base (e.g., along the z-axis, as illustrated in  FIG. 25 ) in order to actuate a switch or dome underneath the keycap  204 . Due to the geometry of the butterfly hinge  304 , as well as the orientation of the butterfly hinge with respect to the keycap  204 , the keycap  204  may also translate laterally along a direction that is substantially in-plane with the keycap  204  (e.g., along the x- or y-axis). For example, as described herein, the butterfly hinge  304  may cause the keycap  204  to travel along an arced path as it is pressed downward, which may result in at least one side of the keycap  204  moving closer to the web  202 . This may cause the keycap  204  to ultimately contact the web  202 , which may cause binding, scraping, or other undesirable interactions. Also, while one side of the keycap  204  may move close to the web  202 , an opposite side of the keycap  204  may move further away from the web  202 , resulting in a gap that may allow debris or other contaminants to fall under the keycap  204 .  FIGS. 26A-30B  show various embodiments of butterfly hinges and other components that may provide different degrees of lateral movement of the keycap  204  during actuation of the key  105 .  FIGS. 26A-29B  generally correspond to a cross-sectional view of the key  105  viewed along line  26 - 26  in  FIG. 25 , though some components and features are omitted for clarity, and some components that would not necessarily be visible in cross-section are shown in phantom lines to better depict the mechanism. Moreover, it will be understood that the key  105  may be substantially symmetrical such that the components and features described with respect to  FIGS. 26A-29B  may be substantially replicated on an opposite side of the key  105 . 
       FIGS. 26A-26B  show one example of the key  105  in an unactuated and an actuated state, respectively. The key  105  includes a butterfly hinge  2600  with a first wing  2602  and a second wing  2604 . The butterfly hinge  2600  may correspond to or be an example embodiment of the butterfly hinge  304 . The first wing  2602  includes a keycap pivot pin  2606  coupled to the keycap and a base pivot pin  2608  coupled to a dome support structure  314  (or any other appropriate component), and the second wing  2604  includes a keycap pivot pin  2610  coupled to the keycap and a base pivot pin  2612  coupled to the dome support structure (or any other appropriate component). The keycap and base pivot pins  2606 ,  2608  may be translationally constrained to the keycap  204  and the dome support structure, respectively (e.g., they can rotate but cannot slide relative to the keycap  204  and the dome support structure  314 ). The keycap and base pivot pins  2610 ,  2612  of the second wing  2604 , on the other hand, may be free to rotate and slide or translate relative to the keycap  204  and the dome support structure  314  at least enough to prevent binding and allow the keycap  204  to move downward during actuation. For example, the channel of the dome support structure  314  in which the base pivot pin  2612  is positioned may be wider than the base pivot pin  2612 , and also wider than the channel in which the base pivot pin  2608  is coupled, thus allowing the base pivot pin  2612  to translate as well as rotate within the channel. The pivot pins of the butterfly hinge  2600  (and indeed any of the butterfly hinges described herein) may be substantially the same size (e.g., length, diameter) and shape as one another. The pivot pins are one example of pivot members that may be used. Other suitable pivot members may include rods, posts, protrusions, arms, etc. 
     The wings  2602 ,  2604  may be configured so that, when the key  105  reaches the end of its travel in an actuated state (e.g., when the key  105  is depressed), the keycap and base pivot pins on each wing are aligned along a line  2614  that is parallel to a plane defined by the base plate  208  (and/or a membrane or other layer  2601  positioned over the base plate  208 ). This configuration may result in the keycap  204  shifting a certain amount in the negative y-direction. For example, a gap  2616  between the keycap  204  and the web  202  may decrease as shown in  FIGS. 26A and 26B . A gap  2618  on the opposite side of the keycap  204  may increase by a corresponding amount. 
       FIGS. 27A-27B  show another example of the key  105  in an unactuated and an actuated state, respectively. While similar to the butterfly hinge  2600  described with respect to  FIGS. 26A-26B , the butterfly hinge  2700  shown in  FIGS. 27A-27B  (which may correspond to or be an embodiment of the butterfly hinge  304 ) results in a different alignment of the pivot pins in the actuated state. In particular, the butterfly hinge  2700  includes a first wing  2702  and a second wing  2704 . The first wing  2702  includes a keycap pivot pin  2706  coupled to the keycap and a base pivot pin  2708  coupled to a dome support structure  314  (or any other appropriate component), and the second wing  2704  includes a keycap pivot pin  2710  coupled to the keycap and a base pivot pin  2712  coupled to the dome support structure (or any other appropriate component). The keycap and base pivot pins  2706 ,  2708  may be translationally constrained to the keycap  204  and the dome support structure, and the keycap and base pivot pins  2710 ,  2712  of the second wing  2704  may be free to rotate and slide (or otherwise translate) relative to the keycap  204  and the dome support structure  314 , as described above. 
     The wings  2702 ,  2704  may be configured so that, when the key  105  reaches the end of its travel in an actuated state (e.g., when the key  105  is depressed), the keycap and base pivot pins on each wing are aligned along a line  2714  that is not parallel to a plane defined by the base plate  208  and/or a membrane  2701 . This configuration may result in the keycap  204  shifting in the negative y-direction a different amount (e.g., less than) the shift exhibited by the butterfly hinge  2600  in  FIG. 26 . The non-parallel alignment of the pivot pins may be achieved by positioning the base pivot pins  2708 ,  2712  in an opening or gap in a membrane  2701  or other layer that is positioned above the base plate  208  (or otherwise configuring the key  105  so that the base pivot pins  2708 ,  2712  are lower than the keycap pivot pins  2706 ,  2710  when the key is actuated). In  FIGS. 26A-26B , on the other hand, when the key  105  is actuated, both the keycap and the base pivot pins are positioned on top of the membrane  2701  such that their central axes are parallel to the base plate  208 . By sinking the base pivot pins  2708 ,  2712  below the top surface of the membrane  2701 , the keycap  204  may translate a different amount along the y-axis during actuation than other configurations. 
       FIGS. 28A-28B  show another example of the key  105  in an unactuated and an actuated state, respectively. While similar to the butterfly hinges  2600  and  2700 , the butterfly hinge  2800  shown in  FIGS. 28A-28B  (which may correspond to or be an embodiment of the butterfly hinge  304 ) results in a different alignment of the pivot pins in the actuated state. In particular, the butterfly hinge  2800  includes a first wing  2802  and a second wing  2804 . The first wing  2802  includes a keycap pivot pin  2806  coupled to the keycap and a base pivot pin  2808  coupled to a dome support structure  314  (or any other appropriate component), and the second wing  2804  includes a keycap pivot pin  2810  coupled to the keycap and a base pivot pin  2812  coupled to the dome support structure (or any other appropriate component). The keycap and base pivot pins  2806 ,  2808  may be translationally constrained to the keycap  204  and the dome support structure, and the keycap and base pivot pins  2810 ,  2812  of the second wing  2804  may be free to rotate and slide relative to the keycap  204  and the dome support structure  314 , as described above. 
     The wings  2802 ,  2804  may be configured so that, when the key  105  reaches the end of its travel in an actuated state (e.g., when the key  105  is depressed), the keycap and base pivot pins on each wing are aligned along a line  2814  that is parallel to a plane defined by the base plate  208  and/or a membrane  2801 , but is closer to the base plate  208  than the mechanism shown in  FIGS. 26A-26B . This alignment of the pivot pins may be achieved by configuring the key mechanism  105  so that at least part of the base pivot pins  2808 ,  2812  and the keycap pivot pins  2806 ,  2810  extend below a top surface of a membrane  2801  (or below a top surface of the base plate  208 ) when the key  105  is actuated. 
       FIGS. 29A-29B  show another example of the key  105  in an unactuated and an actuated state, respectively.  FIGS. 29A-29B  show a butterfly hinge  2900  that includes a first wing  2902  and a second wing  2904 . The first wing  2902  includes a keycap pivot pin  2906  coupled to the keycap and a base pivot pin  2908  coupled to a dome support structure  314  (or any other appropriate component), and the second wing  2904  includes a keycap pivot pin  2910  coupled to the keycap and a base pivot pin  2912  coupled to the dome support structure (or any other appropriate component). The keycap and base pivot pins  2910 ,  2912  of the second wing  2904  may be free to rotate and slide relative to the keycap  204  and the dome support structure  314 , as described above. 
     Instead of a simple rotating pivot, the base pivot pin  2908  may have a non-circular or cam profile that causes the keycap  204  to travel through a path that is different than what is achieved with a simple rotating pivot, such as those shown in  FIGS. 26A-28B . Additionally, the channel  2905  in which the base pivot pin  2908  is positioned may have a non-circular shape that interacts with the non-circular or cam profile of the base pivot pin  2908  to produce a desired travel path of the keycap  204 . The shapes and positions of these components may result in less lateral motion of the keycap  204  during actuation of the key  105  than may be achieved with other designs, including designs using simple rotating pivots. 
       FIG. 30A  shows a schematic view of an arm  3000  of a butterfly hinge that has a simple rotating base pivot pin  3002 . When the arm  3000  moves from the unactuated state (shown in solid lines) to the actuated state (shown in dashed lines), the end of the arm  3000  moves through a substantially circular arc  3004 .  FIG. 30B  shows a schematic view of an arm  3006  of a butterfly hinge that has a base pivot pin  3008  with a non-circular or cam profile, such as the base pivot pin  2908  in  FIG. 29 . When the arm  3006  moves from the unactuated state (shown in solid lines) to the actuated state (shown in dashed lines), the end of the arm  3006  moves through an arc  3010 . The arc  3010  may result in substantially less lateral translation (e.g., along the y-axis) than the circular arc  3004 , which in turn may result in less lateral translation of a keycap  204 . In some cases, the arc  3010  may be substantially linear. 
       FIG. 31  shows a butterfly hinge  304  of a representative key  105  positioned on the base plate  208 . As noted above, the base plate  208  may define a plurality of openings  210  that may, among other functions, provide clearance underneath components of the keys to provide a space for debris to accumulate without causing binding and/or other interference with the motion of the key.  FIG. 31  also shows recesses  3102  that may be formed in the butterfly hinge  304  to provide additional clearance between the butterfly hinge  304  and the base plate  208 , or other nearby components.  FIGS. 32A-32B  show cross-sectional views of the butterfly hinge  304  and the base plate  208  viewed along lines  32 A- 32 A and  32 B- 32 B, respectively, in  FIG. 31 . 
     As shown in  FIG. 32A , an opening  210  is positioned below cross-beams  3202  of the butterfly hinge  304  when the butterfly hinge  304  is in an actuated state (e.g., corresponding to a key  105  being depressed). Similarly, as shown in  FIG. 32B , an opening  210  is positioned below arm portions  3204  of the butterfly hinge  304  when the butterfly hinge  304  is in an actuated state. If the base plate  208  were continuous under these portions of the butterfly hinge  304 , a piece of debris, such as sand, crumbs, dust, or the like, may interfere with the movement of the butterfly hinge  304  during actuation of the key  105 . By providing the openings in the positions shown, sufficient clearance may exist to allow the key  105  to continue to operate despite the presence of debris or other contaminants. In some cases, the openings  210  and the butterfly hinge  304  is configured such that 50% or more (e.g., up to 90%) of the surface of the butterfly hinge  304  that faces the base plate  208  does not contact the base plate  208  when the key  105  is actuated. 
       FIGS. 32A-32B  also show the recesses  3102  that may provide additional clearance between the butterfly hinge  304  and adjacent components. The recesses  3102  may be any appropriate depth or shape, and may be positioned in any appropriate location on the butterfly hinge. As shown, the butterfly hinge  304  includes recesses  3102  on both top and bottom surfaces, providing clearance between the butterfly hinge  304  and the base plate  208  as well as a keycap  204  (not shown in  FIGS. 32A-32B ). 
     The representative key  105  discussed with respect to the foregoing figures is one representative key of a keyboard. However, not all keys on a keyboard are necessarily identical. For example, different keys may have different stroke lengths, tactile responses, keycap sizes, keycap shapes, keycap aspect ratios, and the like. For example, a space bar, shift key, or return key of a keyboard may be wider than a typical letter key. In such cases, some or all of the components of a corresponding switch assembly may be enlarged in order to provide suitable mechanical and/or electrical functionality to the key. As one example, for a shift key, the butterfly hinge  304  may be elongated in the same manner as the keycap in order to adequately support the keycap. Alternatively, multiple butterfly hinges, each the same size as one from a corresponding letter key, may be used (e.g., one butterfly hinge at each end of the space bar. Each key may include only one dome, however. For example, where multiple butterfly hinges are used for a single key, a single dome may be positioned between the two butterfly hinges such that a central portion of the keycap actuates the dome. 
     Where a key is smaller than a typical letter key of the keyboard, such as for a “function row” (e.g., a set of keys above the standard alphanumeric keys of an English keyboard that typically control one or more functions of a device apart from text or data entry), any or all of the components of a corresponding switch assembly may be smaller than those of a typical letter key.  FIG. 33  shows an exploded view of an example key  107  that may be used for keys with a smaller keycap or a different aspect ratio than the key  105 . The key  107  includes a cover member  3302 , a dome  3304 , a dome support structure  3306 , an actuation mechanism  3308  (e.g., a butterfly hinge or other hinge mechanism), an adhesive  3310 , and a base  3312  (e.g., the base plate  208  or a portion thereof). Each of these components may provide the same or similar function as the corresponding components of the key  105 , but may be sized or shaped to accommodate the different sized keycap. 
     In some cases where the key  107  is smaller than the key  105 , the dome  3304  may have a different configuration than the dome  402 . For example, instead of having a generally circular dome portion with four retention features  406  extending from an outer edge of the dome, the dome  3304  may have an oblong dome portion with two retention features  3314  extending from opposite ends of the dome  3304 . The dome support structure  3306  may define an opening  3316  having a shape that generally corresponds to the dome  3304 . The dome support structure  3306  may also include retention surfaces  3318  that engage the retention features  3314  to retain the dome  3304  in the opening. The retention features  3314 , retention surfaces  3318 , and the cover member  3302  may provide substantially the same functionality as the corresponding components of the key  105  (e.g., retaining the dome  3304  to the dome support structure  3306  to aid in manufacturing and/or assembly of a keyboard). Similarly, the dome support structure  3306  may define channels  3320  that are configured to engage pivot pins  3322  of the actuation mechanism  3308  in the same or similar manner as in the key  105 . 
       FIG. 34  shows a flow chart of an example method  3400  for assembling a keyboard, such as the keyboard  102 , described above. The method  3400  may be implemented all or in part by pick-and-place machines, tape-and-reel machines, SMT machines, or any other component placement machines or apparatuses. As described above, the use of such machines may be facilitated or enabled by components that can be assembled by machines into self-contained, modular subassemblies and that are designed to self-align with each other during assembly. 
     At operation  3402 , a keyboard base plate is prepared. The base plate may be the base plate  208 , or any other appropriate keyboard base plate or substrate. The base plate may be any appropriate material or component, such as a printed circuit board, a flexible circuit board, or the like. Preparing the base plate may include heat treating and/or curing the base plate. For example, the base plate may be heated to dry and/or cure the base plate until it becomes dimensionally stable. Performing the heat treating and/or curing operation at this stage may help prevent detrimental dimensional changes later during the keyboard assembly process. For example, components may be heat staked or soldered to the base plate. If the base plate is not dimensionally stable prior to such operations, the heat from such operations may cause the base plate to shrink, expand, warp, or otherwise change shape. Accordingly, heat treating and/or curing the base plate prior to other assembly steps may help maintain the dimensional stability of the base plate during later assembly phases. 
     Preparing the base plate may also include forming conductive paths or traces (including, for example, the electrical contacts  418 ,  420 ,  FIG. 4 ) on the base plate. Such paths or traces may be formed in any appropriate way, including photolithography, applying wires to the base plate, or the like. Preparing the base plate may also include forming openings such as the openings  210  ( FIG. 2 ) and  424  ( FIG. 4 ) in the base plate. Such openings may be formed by drilling, machining, laser cutting, water jet cutting, or any other suitable operation. 
     At operation  3404 , an input subassembly is assembled. Assembling the input subassembly (which may correspond to a switch assembly  206 ,  FIG. 2 ) may include positioning a collapsible dome (e.g., the dome  402 ,  FIG. 4 ) in an opening of a dome support structure (e.g., the dome support structure  314 ,  FIG. 3 ) to engage the collapsible dome with the dome support structure. For example, the collapsible dome may be positioned in an opening of the dome support structure such that suspension arms or other retention features of the dome are positioned in recesses in the dome support structure such that the suspension arms or retention features overlap retention surfaces of the dome support structure. 
     Assembling the input subassembly (operation  3404 ) may also include coupling a cover member (e.g., the cover member  316 ,  FIG. 3 ) to the dome support structure such that the collapsible dome is retained between the cover member and a retention surface of the dome support structure. For example, a cover member may be glued, welded (e.g., laser welded, ultrasonically welded), or otherwise bonded to the dome support structure. Because of the cover member and the overlap between the dome&#39;s suspension arms and the dome support structure&#39;s retention surfaces, the dome, input subassembly, and cover member form a modular, self-contained switch package. For example, the dome is retained within the opening of the dome support structure such that the switch package can be moved or otherwise manipulated without becoming disassembled. Moreover, because the dome is secured in a supporting component (the dome support structure), aspects of the switch package can be tested in an assembly-ready configuration. That is, the actual switch package that is intended to be included in a keyboard can be tested to detect any defects prior to being incorporated into a keyboard. In contrast, where each individual component is separately coupled to a keyboard base plate during assembly, it may not be possible (or it may be more difficult or less efficient) to test the operation of certain components prior to assembly. As one example, where components must be separately assembled to a keyboard base, it may be difficult to ensure proper engagement between a dome and a dome support structure until after they are both coupled to the base plate, at which time removal and repair may be difficult, time consuming, costly, or otherwise not practical. 
     The operation  3404  of assembling the input subassembly may include coupling a butterfly hinge (e.g., the butterfly hinge  304 ) to the dome support structure. For example, the dome support structure may include retention channels, and the butterfly hinge may include pivot pins. Accordingly, coupling the butterfly hinge may include capturing a pivot pin (or a plurality of pivot pins) of the butterfly hinge in a retention channel (or a plurality of retention channels) of the dome support structure. Examples of retention channels and pivot pins, and various examples of their shapes and interactions, are described herein. The butterfly hinge may be coupled to the dome support structure prior to the operation  3406  (below) of coupling the input subassembly to the base plate. 
     At operation  3406 , the input subassembly is coupled to a base plate. The input subassembly, which may include the dome, dome support structure, cover member, and butterfly hinge, may be coupled to the base plate in any appropriate manner. For example, clips, pins, posts, or other members of the dome support structure may be inserted into openings in the base plate to retain the dome support structure (and thus the whole input subassembly) to the base plate. The members that are inserted into the openings may be heat staked to the base plate, or may otherwise mechanically engage with the base plate. Additionally or alternatively, the dome support structure may be adhered to the base plate. For example, an adhesive, such as a pressure sensitive adhesive, heat sensitive adhesive, or any other adhesive or bonding agent, may be applied to one or both of the dome support structure and the base plate, and the dome support structure may be assembled to the base plate to form a bond therebetween. 
     Coupling the input subassembly to the base plate at operation  3406  may result in the pivot pin (or pins) of the butterfly hinge being retained between a wall of the retention channel (or channels) and the base plate. That is, the pivot pins are captured in the channel by the walls of the channel as well as a surface of the base plate. As described herein, capturing the pivot pins in this way retains the butterfly hinge to the keyboard while also facilitating pick-and-place assembly techniques. 
     Coupling the input subassembly to the base plate at operation  3406  may also result in the collapsible dome forming an electrical connection with an electrical contact on the base plate. For example, the configuration of the input subassembly and the base plate may be such that when the input subassembly is coupled to the base plate, the collapsible dome, which is retained to the dome support structure, is properly positioned relative to electrical contacts on the base plate (e.g., the electrical contacts  418 ,  420 ,  FIG. 4 ). Moreover, the collapsible dome and the dome support structure may be configured such that, when coupled to the base plate, a portion of the collapsible dome is biased against the electrical contacts. More particularly, the cover member may bias the dome towards the base plate such that one or more suspension arms (e.g., suspension arms  904 ,  FIG. 9 ) are pressed against electrical contacts with sufficient force to maintain a positive electrical contact between the dome and the electrical contacts during use of the keyboard. 
     The electrical contact between the dome and the electrical contacts of the base plate may be formed without soldering the dome to the electrical contacts. Indeed, in some cases, it is not necessary to solder or otherwise fuse the dome to the keyboard, and the electrical contact may be maintained solely by mechanical force. In some embodiments, a soldering or other fusing operation is used to form the electrical connection. For example, solder balls may be included on one or both of the suspension arms and the electrical contacts, and a reflow operation may be performed after one or more of the switch subassemblies are coupled to the base plate to fuse the domes to the electrical contacts. 
     As described herein, the components described herein facilitate assembly using pick-and-place or SMT assembly technology, and various operations of the method  3400  may be performed using such machines. For example, the operation of coupling the butterfly hinge to the dome support structure may include securing the dome support structure (which may include a collapsible dome and a cover member coupled thereto) to an assembly head of a component placement apparatus (e.g., a pick-and-place machine). After securing the dome support structure to the assembly head, the assembly head may position the pivot pin (or pivot pins) of the butterfly hinge in the retention channel (or retention channels) of the dome support structure, and then secure the butterfly hinge to the assembly head. For example, the assembly head may pick up a dome support structure, move the assembly head to an available butterfly hinge, place the dome support structure in the opening defined by the butterfly hinge (e.g., the area inside the wings) such that the pins are received in the channels, and then pick up both the butterfly hinge and the dome support structure. The input subassembly may then be positioned on the base plate and released from the assembly head. 
     Where pick-and-place or SMT machines are used to assemble the switch subassemblies and couple the switch subassemblies to the base plate, components may be provided to the machines using tape-and-reel systems. For example, multiple butterfly hinges may be formed on a carrier or web that can be provided to an assembly machine on rolls or strips that hold multiple butterfly hinges. The assembly machine may separate individual butterfly hinges as they are needed for assembly. Similarly, an assembly machine may be provided with multiple switch packages (e.g., pre-assembled units that include dome support structures, collapsible domes, and cover members) on rolls or strips. The switch packages may be separated from a web or other carrier as they are needed for assembly. 
     In some cases, the switch packages are formed in a similar manner. For example, domes, dome support structures, and/or cover members may be provided to an assembly machine on webs, tapes, or other carriers to be separated from the carriers as they are needed. Assembled switch packages may be provided directly from the assembly operation to a keyboard assembly operation, as described above, or they may be tested or otherwise further processed prior to being assembled into a keyboard. 
     Any of the components described herein may include fiducial markers (or simply “fiducials”) that facilitate pick-and-place or other automated assembly and manufacturing processes. For example, switch packages and butterfly hinges may each include fiducials to facilitate assembly of an input subassembly. More particularly, an assembly machine may include cameras, vision systems, or other sensors that detect the fiducials to help identify, locate, and position the components relative to one another during assembly of the input subassembly. Similarly, a keyboard base plate may include fiducials to help position input subassemblies relative to the base plate during assembly of the keyboard. Fiducials may be incorporated in or on the components in any appropriate way. For example, they may be printed, applied (e.g., as a sticker or other layer), etched, molded, machined, or the like. 
     The foregoing description, for purposes of explanation, used 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. Also, when used herein to refer to positions of components, the terms above and below, or their synonyms, do not necessarily refer to an absolute position relative to an external reference, but instead refer to the relative position of components with reference to the figures.

Metadata:
Filing Date: 20160919
Publication Date: 20180925
Grant Date: 20180925
Priority Date: 20150513
Inventors: KNOPF, ERIC A.
CASEBOLT, MATTHEW P.
LEONG, Craig C.
CAO, ROBERT Y.
ZERCOE, BRADFORD J.
MATHEW, DINESH C.
GAO, ZHENG
BROOKS, Ryan P.
WANG, PAUL X.
BERG, BRUCE E.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01H2203/038", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2203/024", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2215/004", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2219/062", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H3/122", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2219/056", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1662", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/023", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2219/062", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2227/022", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2219/062", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/88", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2239/056", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2223/054", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/7065", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H2215/004", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/705", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H13/705", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2231/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2227/022", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/7065", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/83", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2227/022", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2223/03", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2219/056", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0202", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2223/054", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/88", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2223/03", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2221/07", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2219/028", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2229/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H3/122", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/70", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/705", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/83", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/88", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2239/074", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2203/038", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1662", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/70", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/023", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/88", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2219/056", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2223/03", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/83", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2219/062", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2227/022", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2203/038", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/7065", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H13/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2215/004", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2219/028", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0202", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H3/122", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2223/054", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2239/074", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2221/07", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2239/056", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1662", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/705", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2229/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0202", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 56080477