PATENT DOCUMENT

Publication Number: US-10083807-B2
Application Number: US-201615163580-A
Country: US
Kind Code: B2

Title: Metal switch for input device

Abstract:
A key mechanism is disclosed. The key mechanism comprises a keycap, a dome support structure positioned relative to the keycap and defining an opening, an actuation mechanism coupled to the keycap, and a collapsible dome positioned in the opening of the dome support structure. The actuation mechanism is configured to movably support the keycap relative to the dome support structure. The dome comprises an upstop member configured to limit upward travel of the collapsible dome.

Claims:
What is claimed is: 
     
       1. A key mechanism, comprising:
 a keycap; a dome support structure positioned relative to the keycap and defining: 
 an opening; and 
 a travel limiting feature; 
 an actuation mechanism coupled to the keycap and configured to movably support the keycap relative to the dome support structure; and 
 a unitary metal dome positioned in the opening of the dome support structure and comprising an upstop member; wherein the keycap is movable between an undepressed position and a depressed position; and in the undepressed position, the upstop member contacts the travel limiting feature of the dome support structure, thereby limiting upward travel of the unitary metal dome. 
 
     
     
       2. The key mechanism of  claim 1 , wherein: the key mechanism further comprises an electrical contact below the unitary metal dome; and in the depressed position, the electrical contact is actuated by the unitary metal dome. 
     
     
       3. The key mechanism of  claim 2 , wherein: in the depressed position, the upstop member is in contact with the electrical contact; and in the undepressed position, the upstop member is not in contact with the electrical contact. 
     
     
       4. The key mechanism of  claim 2 , wherein: the key mechanism further comprises a substrate below the unitary metal dome; and in the depressed position, the upstop member contacts the substrate such that the upstop member deflects. 
     
     
       5. The key mechanism of  claim 4 , wherein: the key mechanism is moved to the depressed position in response to an actuation force on the keycap; and when deflected, the upstop member imparts on the keycap a returning force that opposes the actuation force. 
     
     
       6. The key mechanism of  claim 4 , wherein: the unitary metal dome further comprises a spring arm; and during actuation of the key mechanism, both the spring arm and the upstop member contact the substrate to impart on the keycap a returning force that opposes an actuation force on the keycap. 
     
     
       7. The key mechanism of  claim 2 , wherein: the unitary metal dome further comprises a spring arm coupled to the dome support structure; in the undepressed position: the spring arm biases the unitary metal dome upwards; and the upstop member opposes the upwards bias of the spring arm. 
     
     
       8. A key mechanism, comprising:
 a keycap; 
 a dome support structure defining a travel limiting feature; and 
 a unitary metal dome coupled to the dome support structure and comprising: an actuation region; a first arm extending from the actuation region, and a second arm extending from the actuation region, wherein when the key mechanism is in an undepressed state, the first arm contacts the travel limiting feature of the dome support structure; and the second arm defines a first end that is coupled to the dome support structure to retain the unitary metal dome to the dome support structure. 
 
     
     
       9. The key mechanism of  claim 8 , wherein when the key mechanism is in a depressed state, the first arm is not in contact with the travel limiting feature. 
     
     
       10. The key mechanism of  claim 8 , wherein the first arm comprises: a first curved portion configured to contact the travel limiting feature; and a second curved portion configured to contact a substrate below the unitary metal dome when the key mechanism is in a depressed state. 
     
     
       11. The key mechanism of  claim 8 , wherein: the unitary metal dome further comprises; a third arm extending from the actuation region and comprising a second end that is attached to the dome support structure to retain the unitary metal dome to the support structure. 
     
     
       12. The key mechanism of  claim 11 , wherein: the travel limiting feature is a first travel limiting feature; the dome support structure defines a second travel limiting feature; and the unitary metal dome further comprises a fourth arm extending from the actuation region, wherein when the key mechanism is in the undepressed state, the fourth arm contacts the second feature of the dome support structure. 
     
     
       13. The key mechanism of  claim 11 , further comprising first and second clips coupled to the dome support structure and configured to receive the first and second ends, respectively, of the first and second arms. 
     
     
       14. A dome for an input mechanism, comprising: an actuation region; first and second cantilevered biasing arms extending from the actuation region; each having a first shape defined at least in part by a first curvature; and first and second cantilevered upstop arms extending from the actuation region, each having a second shape defined at least in part by a second curvature that is different than the first curvature. 
     
     
       15. The dome of  claim 14 , wherein the first and second cantilevered biasing arms each comprise: a first portion adjacent the actuation region and having a convex shape; and a second portion adjacent the first portion and having a concave shape. 
     
     
       16. The dome of  claim 15 , wherein: the convex shape has a first radius; and the concave shape has a second radius greater than the first radius. 
     
     
       17. The dome of  claim 14 , wherein: the first and second cantilevered biasing arms extend from first opposing sides of the actuation region; and the first and second cantilevered upstop arms extend from second opposing sides of the actuation region. 
     
     
       18. The dome of  claim 14 , wherein distal ends of the first and second cantilevered biasing arms and the first and second cantilevered upstop arms are not coupled to one another. 
     
     
       19. The key mechanism of  claim 1 , further comprising a deformable cover attached to the dome support structure over the unitary metal dome and configured to deform when the unitary metal dome is collapsed by the actuation mechanism. 
     
     
       20. The dome of  claim 14 , wherein:
 the first cantilevered biasing arm defines a first tab at a distal end of the first cantilevered biasing arm; 
 the second cantilevered biasing arm defines a second tab at a distal end of the second cantilevered biasing arm; and the first and second tabs are configured to engage a dome support structure to retain the dome to the dome support structure.

Description:
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. 
     SUMMARY 
     A key mechanism comprises a keycap, a dome support structure positioned relative to the keycap and defining an opening, an actuation mechanism coupled to the keycap, and a collapsible dome positioned in the opening of the dome support structure. The actuation mechanism is configured to movably support the keycap relative to the dome support structure. The collapsible dome comprises an upstop member configured to limit upward travel of the collapsible dome. 
     A key mechanism comprises a frame member defining a travel limiting feature, and a switch member coupled to the frame member. The switch member comprises an actuation region and an arm extending from the actuation region. When the key mechanism is in an undepressed state, the arm contacts the travel limiting feature. 
     A dome for an input mechanism comprises an actuation region, first and second cantilevered biasing arms extending from the actuation region, and a cantilevered upstop arm extending from the actuation region. 
    
    
     
       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 a key. 
         FIG. 3  shows an exploded view of a switch assembly. 
         FIGS. 4A-4B  show partial cross-sectional views of the key of  FIG. 2 . 
         FIGS. 5A-5B  show partial cross-sectional views of the key of  FIG. 2 . 
         FIG. 6  shows a force versus travel curve of the key of  FIG. 2 . 
         FIG. 7  shows a partial cross-sectional view of the key of  FIG. 2 . 
         FIG. 8  shows a partial cross-sectional view of the key of  FIG. 2 . 
         FIG. 9  shows an exploded view of another switch assembly. 
         FIG. 10  shows a portion of yet another switch assembly. 
         FIG. 11  shows an example dome for use in the key of  FIG. 2 . 
         FIG. 12  shows another example dome for use in the key of  FIG. 2 . 
     
    
    
     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. 
     Rubber domes may provide biasing and switching functionality, but they may not be suitable for all applications. For example, rubber domes may not be suitable for keys with travel shorter than about 1.0 mm. Metal domes may be used for keys with travel shorter than about 0.5 mm, but traditional metal dome designs may be less reliable than is desired, and they may not be well suited for keys with travel above about 0.5 mm. 
     Described herein are key mechanisms, and domes for use in key mechanisms, that combine high reliability and durability with a desirable tactile response and stroke length. For example, a key mechanism may include a metal dome with arms extending from a central portion to form a cross shape. Some of the arms may act as spring or biasing arms that provide a biasing force to a keycap, but also allow the dome to deform or collapse under an actuation force. Other arms may act as upstop arms that interact with a travel limiting structure or feature of the key mechanism to limit upward travel of the keycap when the actuation force is removed (e.g., when the key is at rest or undepressed). Upstop arms may also be pressed against a lower surface of the keyboard when the key is depressed, causing the upstop arms to deflect and provide additional biasing or returning force on the keycap. 
       FIG. 1  shows a computing device  100  having a keyboard  102  incorporated therein. As shown, the computing device  100  is a laptop computer, though it can be any suitable computing device, such as, for example, a desktop computer, a telephone, smart phone, 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  includes a plurality of keys, including a representative key  104 . While the instant application describes components of a representative key  104  of a keyboard  102 , the concepts and components described herein apply to other depressible input mechanisms as well, such buttons, stand-alone keys, switches, or the like. Moreover, such keys, buttons, or switches may be incorporated into other devices, such as smart phones, tablet computers, or the like. 
       FIG. 2  shows an exploded view of the key  104 . The key  104  includes a keycap  202  coupled to an optional actuation mechanism  200  that allows the keycap  202  to move between a depressed and an undepressed position. The actuation mechanism  200  may include a first wing  204 , a second wing  206 , and a hinge  208  coupling the first wing  204  to the second wing  206 . The hinge  208  may include any appropriate mechanism or material that attaches the first wing  204  to the second wing  206  while allowing the first wing  204  and the second wing  206  to articulate or move relative to each other. For example, the hinge  208  may include a gear hinge or a living hinge (e.g., a flexible material coupled to both the first and second wings  204 ,  206 ). Other mechanisms may be used instead of the actuation mechanism  200 , such as scissor mechanisms or the like. In some cases, the actuation mechanism  200  may be omitted and the keycap  202  may be coupled to a switch member  218  that supports the keycap  202 , biases the keycap  202  to an undepressed position, and provides switching functionality to the key  104 . The switch member  218  may correspond to the dome  308  in  FIG. 3 . 
     The keycap  202  may be coupled to the first and second wings  204 ,  206  via pins  212  extending from the first and second wings  204 ,  206 . The keycap  202  may include retention clips  214  extending from an underside of the keycap  202  that engage the pins  212 . One pair of the retention clips  214  may allow its corresponding pins  212  to rotate therein, while the another pair may allow its corresponding pins  212  to rotate and slide therein. When the key  104  is actuated (e.g., pressed downward) the ends of the first and second wings  204 ,  206  where the pins  212  are located will move away from one another. By including at least a pair of retention clips  214  that allow the pins to slide relative to the keycap  202 , the wings  204 ,  206  can articulate relative to one another without being mechanically bound by the retention clips  214 . While  FIG. 2  shows the pins  212  coupled to the wings  204 ,  206  and the retention clips  214  coupled to the keycap  202 , the locations of the pins  212  and retention clips  214  may be swapped. 
     The key  104  also includes a switch assembly  203 . The switch assembly  203  includes a dome support structure  210 , the switch member  218  (e.g., corresponding to the dome  308 ,  FIG. 3 ) coupled to the dome support structure  210 , and a dome cover  216 . The switch assembly  203  is configured to provide a biasing force and other switching functionality of the key  104 . For example, arms  220  of the switch assembly  218  may bias the keycap  202  to an undepressed position, determine travel limits of the keycap  202  (both in an undepressed and a depressed position), and provide a particular force response to the key  104 . The arms  220  may correspond to the first and second arms  312 ,  314  in  FIG. 3 . 
     The wings  204 ,  206  may be pivotally coupled to the switch assembly  203 , and in particular, to the dome support structure  210 . The dome support structure  210  may be fixed to a substrate (e.g., the substrate  318 ,  FIG. 3 ), such as a keyboard base plate, a circuit board, a surface of an electronic device housing, or the like. Thus, the dome support structure  210  may serve as a mechanical link between a substrate, the wings  204 ,  206 , and the keycap  202 . In some cases, the wings  204 ,  206  may be pivotally coupled to a substrate of the keyboard instead of or in addition to being coupled to the switch assembly. 
     The dome cover  216  covers at least a portion of the dome support structure  210  and may act as a seal for the switch assembly  203 , preventing or reducing the likelihood that dirt, moisture, or other contaminants will get inside the dome support structure  210 . The dome cover  216  may be flexible such that an actuation force applied to the dome cover  216  from the keycap  202  will deform the dome cover  216  and be transmitted to components under the dome cover  216  (such as the dome  308 ,  FIG. 3 ). The dome cover  216  may be any appropriate material, such as a flexible polymer (e.g., silicone) or fabric, and may be coupled to the dome support structure  210  in any appropriate way, such as with an adhesive. 
       FIG. 3  shows an exploded view of the switch assembly  203 . The switch assembly  203  includes the dome support structure  210 , a dome  308 , the dome cover  216 , and retention clips  310 . As noted above, the switch assembly  203  may be coupled to a substrate  318 , which may be a circuit board, base plate, housing, or the like, and which may include electrical contacts  324  that provide electrical switching functionality, as described herein. 
     The dome support structure  210  may be coupled to the substrate  318  in any appropriate way. For example, the dome support structure  210  may include pins, posts, clips, or other features extending downward and configured to be inserted into or otherwise engage with openings  320  of the substrate  318  to retain the dome support structure  210  to the substrate  318 . Adhesives such as heat sensitive adhesives, pressure sensitive adhesives, or the like, may be used to secure the dome support structure  210  to the substrate  318 . Adhesives may be used instead of or in addition to a mechanical engagement between the dome support structure  210  and the substrate  318  (such as the pins and openings described). 
     The dome support structure  210  defines an opening  322  in which a dome  308 , or any other switch member, may be positioned. The retention clips  310  may be coupled to the dome support structure  210 , and may include slots, cavities, channels, openings, recesses, or other features to receive a part of the dome  308  (e.g., an end of a spring arm  312 , discussed below) and retain the dome  308  to the dome support structure  210 . In some cases, instead of or in addition to the retention clips  310 , the dome support structure  210  may include retention features on surfaces  304 , such as slots, cavities, channels, openings, recesses, or other features that receive and retain part of the dome  308 . 
     The dome support structure  210  further includes travel limiting features, such as upstops  306 , that are configured to be contacted by upstop arms of the dome  308  to limit upward travel of the dome  308 . For example, as shown in  FIG. 3 , the upstops  306  are undercuts that define a downward facing surface. Upstop arms  314  of the dome  308 , discussed below, may extend under the upstops  306  such that when the dome  308  is biased in an upward or unactuated direction, the upstop arms contact the downward facing surface of the undercut and limit further upward travel of the dome  308 . The upstops  306  need not be undercuts in all implementations, but may be any surface or feature that interacts with upstop arms to limit travel of the dome  308 . For example, the upstops  306  may instead be slots, recesses, channels, or openings into which the upstop arms  314  extend. 
     The dome  308  provides a biasing force to the key  104  and may contribute to the tactile feel of the key  104  when the key  104  is actuated. In particular, the dome  308  is configured to deform or otherwise collapse when subjected to an actuation force, and is configured to return to an undeformed/uncollapsed state when the actuation force is removed. The resistance of the dome  308  to deformation or collapse, as well as the force caused by the dome returning to its undeformed or uncollapsed shape, is at least partly responsible for the particular tactile response of the key  104 , as discussed herein. 
     The dome  308  includes first arms  312  and second arms  314  extending from an actuation region  316 . The actuation region  316  is disposed relative to the keycap  202  such that, when the keycap  202  is actuated or depressed, an actuation force is transferred to the actuation region  316 . For example, the dome cover  216  may include an actuation member  301 , such as a post or protrusion integrally formed with or coupled to the dome cover  216 , that transfers the actuation force from the keycap  202  to the actuation region  316  of the dome  308 . More particularly, an underside of the keycap  202  may contact a top surface of the actuation member  301  and the bottom surface of the actuation member  301  may contact the actuation region  316  of the dome  308 , thus transferring the actuation force from the keycap  202  to the dome  308 . 
     The actuation region  316  may define a surface against which the actuation force (e.g., via the actuation member  301 ) is applied to the dome  308 . The actuation region  316  may be substantially planar, convex, concave, or it may have any other appropriate shape or profile. 
     The first arms  312  and the second arms  314  may be cantilevered from the actuation region  316  and form a cross-shaped dome. In particular, each arm may have a first end and a second end, where the first end joins or is coupled to the actuation region  316  and the second end (the distal end) is free (e.g., it is not connected to the actuation region  316  or to the other arms except via its own arm). In the depicted example, and as described herein, the first arms  312  are spring arms and the second arms  314  are upstop arms. 
     The first arms  312 , also referred to as spring arms  312 , are configured to impart a biasing force that biases the dome  308  (and certain components coupled to or in contact with the dome  308 , such as the keycap  202 ) in an undepressed or unactuated state. For example, as described herein, the spring arms  312  are configured such that an actuation force applied to the dome will cause the dome to deform and contact or otherwise actuate switching components of the key  104 . When the dome  308  is deformed in response to an actuation force, the force produced by the spring arms  312  trying to return to their undeformed shape causes the dome  308  to return to the undepressed or unactuated state. The shape, material, and dimensions, of the spring arms  312 , as well as the coupling between the spring arms  312  and the dome support structure  210 , may influence or determine the amount of force required to collapse the dome  308 , the length of travel of the dome  308 , and other appropriate physical or operational parameters. 
     The dome  308  may be configured so that substantially all of the deformation of the dome  308  in response to an actuation force is due to deformation of the spring arms  312 . For example, in contrast to domes where a central actuation portion changes shape when depressed (such as a convex dome that collapses into a concave or flat shape), the dome  308  may be configured so that the actuation region  316  remains substantially undeformed when subjected to typical actuation forces. In this way, the flexibility and deformation of the spring arms  312  are responsible for the actuation of the switch, rather than the flexibility and deformation of the actuation region  316 . In some cases, the actuation region  316  may be configured to deform or collapse in response to an actuation force in addition to or instead of the spring arms  312 . 
     The spring arms  312  couple the dome  308  to the dome support structure  210 . For example, the distal ends of the spring arms  312  may be received in slots, cavities, channels, openings, recesses, or other features of the retention clips  310  (and/or the retention features on the surfaces  304 ), thereby coupling and retaining the dome  308  to the dome support structure  210 . The retention clips  310  may be coupled to the dome support structure  210  in any appropriate way. For example, the retention clips  310  may be disposed in slots in the dome support structure  210 , as shown in  FIG. 3 . Additionally or alternatively, they may be clipped, fastened (e.g., with a screw or other fastener), bonded, heat-staked, insert molded, or the like, to the dome support structure  210 . In some cases, the retention clips  310  and the dome support structure  210  are formed from or comprise different materials. For example, the dome support structure  210  may be a polymer material, and the retention clips  310  may comprise a metal material (e.g., stainless steel). 
     The second arms  314 , also referred to as upstop arms  314 , are configured to interact with the dome support structure  210  (or another component) to limit upward travel of the dome  308  (e.g., travel in a direction that is opposite an actuation direction). For example, the upstop arms  314  may not be retained to the dome support structure  210 , but instead may be free to move relative to the dome support structure  210  during actuation of the key  104 . For example, the upstop arms  314  may contact the underside of the upstops  306  when the key  104  is in an undepressed or unactuated state, thereby limiting upward travel of the dome  308  beyond a certain amount. When the key  104  is in a depressed or actuated state, the up stop arms  314  may no longer be in contact with the upstops  306 , and instead may be in contact with a substrate below the dome  308 , as described herein. 
     While the dome  308  includes two spring arms  312  and two upstop arms  314 , this is merely one example configuration, and different embodiments may have a different number of each type of arm. For example, a dome may include two spring arms  312  (or other biasing arms) and one upstop arm  314 , or it may include four spring arms  312  and two upstop arms  314 . As yet another example, a dome may include three spring arms  312  and two upstop arms  314 . Other configurations, including any appropriate amount of each type of arm, are also possible. 
     The dome  308  may be formed from a metal material, such as a steel (e.g., stainless steel), aluminum, copper, gold, or tin. Other materials may also be used, such as composites (e.g., carbon fiber) or polymers. The dome  308  may be a unitary structure, such as a single, monolithic piece of metal that has been stamped or otherwise formed as a unitary component. Alternatively, the dome  308  may be formed from multiple parts assembled together. In such cases, the dome  308  may be formed from or comprise one material or multiple materials. For example, the first and second arms  312 ,  314  may be formed from or comprise one material (e.g., stainless steel), and the actuation region  316  may be formed from or comprise a different material (e.g., copper). The various parts may be coupled to one another to form the dome  308  in any appropriate way, including adhesives, mechanical fasteners, welds, solders, interlocking structures, or the like. 
     The configuration of the cantilevered first and second arms  312 ,  314  described herein may result in a dome  308  that is both durable and that has a desirable stroke length and tactile feel. In particular, the flexibility of the arms resulting from the arms  312 ,  314  being cantilevered from the actuation region  316  may reduce or eliminate stresses that may occur if the ends of the arms are coupled to one another or if the dome is formed from a hemispherical or other continuous dome. Further, the lower stresses experienced by the dome  308  allow the dome  308  to be designed with greater stroke length than would be possible or practical with other dome designs. For example, the dome  308  may have a stroke length of greater than 0.5 mm, greater than 0.75 mm, or greater than 1.0 mm. Shorter stroke lengths are also possible (e.g., 0.5 mm or less) and such domes may also benefit from increased durability and improved tactile response provided by the configuration of the dome  308 . 
     The dome  308  is merely one example of a switch member that may be used in the key mechanisms described herein, and other switch members, including switch members of different shapes, sizes, and configurations may also be used. For example, an alternative switch member may have arms that are longer or shorter than the first and second arms  312 ,  314  of the dome  308 . As another example, the actuation region of an alternative switch member may be larger relative to the lengths of its arms, or may have a different shape than the actuation region of the dome  308  (e.g., a circular shape rather than a square shape). Other variations and modifications are also contemplated. 
       FIG. 4A  is a partial cross-section of the key  104  viewed along line  4 - 4  in  FIG. 2 , illustrating the key  104  in an unactuated or undepressed state. For clarity, some portions, components, or features of the key  104  are omitted from the view shown. 
     As shown in  FIG. 4A , the distal ends of the spring arms  312  are received in openings in the retention clips  310  of the dome support structure  210 , thereby retaining the dome  308  to the dome support structure  210 . While not shown, the retention clips  310  may be omitted, and the distal ends of the spring arms  312  may be received into retention features (e.g., openings or recesses) on the surfaces  304  of the dome support structure  210 . As yet another option, the distal ends of the spring arms  312  may pass through openings in the retention clips  310  and into openings or recesses in the surfaces  304 . 
     In the unactuated state shown in  FIG. 4A , the spring arms  312  may be strained or deformed. For example, the dome  308  and the dome support structure  210  may be configured such that the spring arms  312  are elastically deformed even when the key  104  is in the unactuated state. The spring arms  312  attempting to return to their unstrained states may produce a retention force that tends to keep the distal ends of the spring arms  312  securely engaged with the retention clips  310  (e.g., a radial force that presses the distal ends of the spring arms  312  into the retention clips  310 ). In some cases, the spring arms  312  may be unstrained (e.g., in a relaxed state) when the key  104  is not actuated. 
     The dome  308  may also include an optional deformable component (not shown) coupled to an underside of the actuation region  316 . The deformable component may contact the substrate  318  and be compressed between the dome  308  and the substrate  318  when the key  104  is actuated. The deformable component may reduce a sound associated with the actuation, change a tactile response of the key  104  (e.g., so the key feels relatively soft to strike), increase the force required to actuate the key  104 , adjust or set a travel distance of the key  104 , increase a durability of the key  104 , or the like. The optional deformable component may be formed from or include any appropriate material, such as silicone, a polyurethane foam, a spring (e.g., a coil spring or a flat spring), a gel, or any other appropriate material or component. The optional deformable component may instead be coupled to the substrate  318 , such that a lower surface of the actuation region  316  contacts an upper surface of the deformable component when the key  104  is actuated. 
       FIG. 4B  is a partial cross-section of the key  104  viewed along line  4 - 4  in  FIG. 2 , illustrating the key  104  in an actuated or depressed state in which the dome  308  is deformed or collapsed. This position or state may occur in response to an actuation force being applied to the actuation region  316  via the actuation member  301 . As shown, the spring arms  312  have deformed such that portions of the spring arms  312  have contacted the substrate  318 . In embodiments where the key  104  includes the optional deformable component, it may be compressed between the dome  308  and the substrate  318 . In some configurations, the dome  308  may be configured so that portions of the spring arms  312  and the actuation region  316  contact the substrate  318  when the key is actuated. 
     In some cases, the state of the key  104  depicted in  FIG. 4B  corresponds to a maximum travel of the key  104  (when subjected to operating forces within a typical range), and is also substantially coincident with or past a travel at which an actuation of the key  104  is registered (e.g., an input that will cause an electronic device to perform an action is detected). In other cases, the key  104  may be configured such that the spring arms  312  are not in contact with the substrate  318  when the maximum travel of the key  104  has been reached. 
     The spring arms  312  may be configured to buckle or otherwise change shape rapidly at a certain point during actuation of the key  104 . For example, the concave portions of the spring arms  312  may be configured to rapidly change to a convex (or other) shape once the dome  308  has been subjected to a certain amount of force or travel. This action may provide a clicking effect when the key  104  is pressed, thus providing positive tactile feedback to a user that the key  104  has been actuated. 
       FIG. 5A  is a partial cross-section of the key  104  viewed along line  5 - 5  in  FIG. 2 , illustrating the key  104  in an unactuated or undepressed state. For clarity, some portions, components, or features of the key  104  are omitted from the view shown. Whereas  FIG. 4A  shows a cross-section through the spring arms  312  of the dome  308 ,  FIG. 5A  shows a cross-section through the upstop arms  314 . 
     In the unactuated state in  FIG. 5A , distal ends  502  of the upstop arms  314  are in contact with the upstops  306  of the dome support structure  210 . In particular, the biasing force imparted to the dome  308  by the spring arms  312  may force the upstop arms  314  against the upstops  306  (or any other feature of the dome support structure  210  that is configured to contact and/or engage the upstop arms  314 ). Thus, while the spring arms  312  bias the dome  308  upwards, the upstop arms  314  limit the upward travel of the dome  308  in response to the biasing force. In this way, a maximum upward travel or position of the dome  308  when the dome  308  is not subjected to an actuation force can be established. 
     The spring arms  312  may be in a strained or deformed state when the key  104  is in the undepressed or unactuated position. For example, in embodiments where the spring arms  312  impart an upward biasing force on the dome  308  in the unactuated position, the biasing force may cause the distal ends  502  of the upstop arms  314  to deflect downward relative to the actuation region  316 , thus producing a force that opposes the biasing force. Ultimately, the biasing force from the spring arms  312  and the opposing force from the up stop arms  314  reach equipoise, and the dome  308  reaches an equilibrium position corresponding to an upward travel limit of the dome  308 . 
     In other cases, the upstop arms  314  may be in a substantially relaxed or unstrained state when the key  104  is in the undepressed or unactuated position. For example, the upstop arms  314  may be sufficiently stiff that they do not undergo substantial strain or deformation when they are in contact with the upstops  306 . As another example, the dome  308  and/or the dome support structure  210  may be configured such that little or no force is being applied to the upstop arms  314  when the key  104  is in an unactuated position, resulting in the upstop arms  314  being substantially unstrained. 
       FIG. 5B  is a partial cross-section of the key  104  viewed along line  5 - 5  in  FIG. 2 , illustrating the key  104  in an actuated or depressed position, such as may occur in response to an actuation force applied to the actuation region  316  via the actuation member  301 . As shown, the dome  308  has been depressed to a position where the upstop arms  314  are in contact with the substrate  318 . After the upstop arms  314  contact the substrate, they may deflect as the dome  308  is further depressed. The deflection of the upstop arms  314  due to contact with the substrate  318  may produce a counteracting force against further depression of the dome  308 , which may provide a desirable tactile response to the key  104 , such as a soft or compliant feeling as the key  104  is actuated. 
     The upstop arms  314  may be configured so that they contact the substrate  318  at a particular time relative to the operation of the spring arms  312  during a key actuation event. For example, the upstop arms  314  may be configured to contact the substrate  318  before, after, or at substantially the same time that the spring arms  312  contact the substrate  318 . As another example, if the spring arms  312  are configured to buckle or otherwise change shape (e.g., to produce a clicking effect when the key is struck), the upstop arms  314  may be configured to contact the substrate  318  before, after, or at substantially the same time that the spring arms  312  buckle. 
     As noted above, the substrate  318  may include electrical contacts  324 . The upstop arms  314  may be configured to contact the electrical contacts  324  when the key  104  is actuated, thus providing a detectible switching event that may be used to indicate actuation of the key  104 . For example, the upstop arms  314  (which may be formed from or comprise a conductive material such as metal) may complete a circuit between the electrical contacts  324 , which may be detected by a processing system associated with the key  104  to register an actuation of the key  104 . While the foregoing example positions the electrical contacts  324  below the upstop arms  314 , electrical contacts  324  could also or instead be positioned below any portion of the dome  308  (e.g., the spring arms  312  or the actuation region  316 ).  FIG. 9 , for example, shows an embodiment where the electrical contacts are disposed below the spring arms  312 . 
     In some cases, the upstop arms  314  are configured to contact the substrate  318 , and thus contact the electrical contacts  324  and register an actuation of the key  104 , at substantially the same time that the dome  308  clicks (e.g., due to a rapid change in shape of the dome  308 ). By configuring the key  104  so that these actions are substantially coincident, the clicking sensation experienced by a user when the key  104  is pressed may convey to the user that the key  104  has been actuated and that an input has been (or should have been) registered. 
     While the foregoing example uses the dome  308  to complete a circuit between the electrical contacts  324 , actuation of the key  104  may be detected in other ways. For example, the key  104  may include, below the dome  308 , a self-contained switching component that registers an actuation when compressed by the dome  308 . As another example, the key  104  may include an optical switch (e.g., at least partially incorporated with the substrate  318 ) that detects a change in proximity of the dome  308  to the substrate  318 . Other switching mechanisms may also be used. 
       FIG. 6  is a force versus travel curve  600  characterizing the force response of the key  104  using the dome  308 . The curve  600  is merely exemplary, and the dome  308  may be tuned to exhibit different force responses by tuning, for example, the shapes, curvatures, materials, or dimensions of the dome  308 . 
     With respect to the curve  600 , as an actuation force causes the keycap  202  to move and the dome  308  begins to deform, the force response of the key  104  increases from point  602  until a pressure point  604  is reached. The pressure point  604  may correspond to a point at which a rapid deformation of the dome  308  begins (e.g., corresponding to a click that may be felt and/or heard by a user). 
     After the pressure point  604 , the responsive force of the dome  308  decreases until it reaches the operating point  606 , which may correspond to any combination of the spring arms  312 , the upstop arms  314 , or the actuation region  316  contacting the substrate  318 . Under normal operating conditions and forces, the operating point  606  may be at or near a maximum travel of the key  104 , and thus may correspond to a point at which the dome is fully or substantially fully collapsed. 
     The key  104  may be configured such that the dome  308  contacts the electrical contacts  324  at any appropriate point along the force versus travel curve  600 . For example, the dome  308  my contact the electrical contacts  324  at or near the pressure point  604 . As another example, the dome  308  my contact the electrical contacts  324  at or near the operation point  606 . As yet another example, the dome  308  my contact the electrical contacts  324  between the pressure point  604  and the operation point  606 . 
     Certain physical characteristics of the dome  308 , such as the material, dimensions, shape, and the like, may determine the particular force versus travel curve exhibited by the key  104 .  FIG. 7  is a partial cross-section of the key  104  viewed along line  4 - 4  in  FIG. 2 , illustrating dimensions that define certain aspects of the dome  308  and that may be adjusted or tuned during a design phase to achieve a desired tactile response. Such dimensions include, for example, a length  712  of the actuation region  316 , a length  708  of the spring arms  312 , a distance  710  that the spring arms  312  extend past the retention clips  310  and/or the retention features on the surfaces  304 , and a height  714  from the bottom of the spring arms  312  to the top of the actuation region  316 . 
     The physical dimensions and characteristics of the curved portions of the dome  308  may contribute to the tactile response of the key  104 . For example, the dome  308  has a first curved portion (e.g., where the spring arms  312  join the actuation region  316 ). The first curved portion, which is convex as shown in  FIG. 7 , may be characterized by a radius  704 . Beyond the first curved portion, the spring arms  312  have a second curved portion (concave in  FIG. 7 ) characterized by a radius  702 . The radius  702  may be greater than the radius  704 , such as at least two times greater than the radius  704 . Each of the first and second curved portions may also be characterized by an eccentricity or other parameter indicating a deviation from a circular or spherical curve. 
     While  FIG. 7  illustrates a symmetrical dome  308  (e.g., where both spring arms  312  have substantially the same dimensions), this need not be the case. For example, the spring arms  312  may have different dimensions, such as different radii, different lengths, different thicknesses, and different end constraints (e.g., an end of one spring arm  312  may be fixed to its respective retention clip  310 , while an end of another spring arm  312  may be configured to slide within the retention clip  310 ). 
     While the actuation region  316  and the spring arms  312  both have uniform thicknesses in  FIG. 7 , this need not be the case. For example, the spring arms  312  may have a different thickness (e.g., a smaller or larger thickness) than the actuation region  316 . As another example, the spring arms  312  may have different thicknesses at different locations along the arms. By configuring the dome  308  with different thicknesses, the flexibility and/or durability of the dome  308  in certain areas may be optimized or tuned. For example, the first curved portion of the dome  308  may have a thickness that is greater than adjacent portions of the spring arms  312  and the actuation region  316 . This may result in a stiffer dome than one where the first curved portion is thinner or the same thickness as surrounding areas. Similarly, the first curved portion of the dome  308  may be thinner than adjacent areas of the dome  308 , thus allowing the dome to be actuated with a lower actuation force. In yet other configurations, the second curved portion of the dome  308  may have a thickness that is larger or smaller than other portions of the dome  308 . 
       FIG. 8  is a partial cross-section of the key  104  viewed along line  5 - 5  in  FIG. 2 , illustrating a shape of the upstop arms  314 . The upstop arms  314  may each have a first curved portion  802  and a second curved portion  804 . The first curved portion  802  may be configured to contact the substrate  318 , and optionally the electrical contacts  324 . The second curved portion  804  may be configured to contact the upstops  306  of the dome support structure  210 . The curved portions  802 ,  804  may provide smooth surfaces to contact both the substrate  318  and the upstops  306 , respectively. For example, a sharp corner or edge at the end of the upstop arm  314  may scratch or score the upstops  306 . The curved portion  804 , on the other hand, provides a smooth, continuous surface that can slide along the upstops  306  without undue friction, scratching, or scoring that may cause damage to the upstop arms  314 , the upstops  306 , or both. 
     Similar to the discussion above with respect to  FIG. 7 , the upstop arms  314  and the actuation region  316  need not have a uniform thickness. For example, the upstop arms  314  may have different thicknesses at different locations along the arms. As another example, the upstop arms  314  may a different thickness (e.g., a smaller or a larger thickness) than the actuation region  316 . 
       FIG. 9  shows an exploded view of a switch assembly  900 . The switch assembly  900  is similar to the switch assembly  203  described with respect to  FIG. 3 , but illustrates an embodiment where the dome  308  is rotated 45 degrees from the position shown in  FIG. 3 . To accommodate this change, the switch assembly  900  includes a dome support structure  901  with a different configuration than the dome support structure  210 . In particular, the opening  908  of the dome support structure  901  is rotated 45 degrees relative to the position of the opening  322  in the dome support structure  210  ( FIG. 3 ). This rotation moves the positions of the upstops  906  (and optional dome retention features on surfaces  904 ) to correspond to positions of the upstop arms  314  and the spring arms  312  in the switch assembly  900 . 
     Additionally, the substrate  910  in  FIG. 9  includes electrical contacts  912  positioned under the spring arms  312  rather than the upstop arms  314 , as shown in  FIG. 3 . This illustrates an alternative positioning of the electrical contacts  912  relative to the dome  308 , and is not limiting. For example, the electrical contacts  912  (or any other switching contacts or mechanisms that may be used instead of or in addition to the electrical contacts  912 ) may be positioned under the upstop arms  314 , under the actuation region  316 , or at any other appropriate location. 
       FIG. 10  shows a portion of a switch assembly in which a dome  1000  includes four spring arms  1004  that are each coupled to a dome support structure  1002 . The dome support structure  1002  and dome  1000  may be substituted for the dome support structure  210  and the dome  308  in the key  104 . 
     Each of the spring arms  1004  extend from an actuation region  1006 , similar to the configuration of the spring arms  312  of the dome  308 . The spring arms  1004  and the actuation region  1006  may incorporate any of the shapes, materials, and configurations of the spring arms  312  and actuation region  316  described above with respect to the dome  308 . Each spring arm  1004  is coupled to the dome support structure  1002  via a retention clip  1008 , and/or an optional retention feature (not shown) of the dome support structure  1002 . 
     The dome  1000  may be configured so that substantially all of the deformation of the dome  1000  in response to an actuation force is due to deformation of the spring arms  1004 . For example, in contrast to domes where a central actuation portion changes shape when depressed (such as a convex dome that collapses into a concave or flat shape), the dome  1000  may be configured so that the actuation region  1006  remains substantially undeformed when subjected to typical actuation forces. In this way, the flexibility of the spring arms  1004  is responsible for the actuation of the switch. In some cases, the actuation region  1006  may be configured to deform or collapse in response to an actuation force in addition to or instead of the spring arms  1004 . 
       FIG. 11  shows a dome  1100  that may be used with the key  104 . Like the dome  308 , the dome  1100  includes spring arms  1104  and upstop arms  1102 . However, each spring arm  1104  of the dome  1100  includes two tabs  1106  at its distal end. When used in the key  104 , the tabs  1106  may be the only portions of the spring arms  1104  that are inserted in the openings or recesses of the retention clips or the retention features of the key  104 . 
       FIG. 12  shows a dome  1200  that may be used with the key  104 . Like the dome  308 , the dome  1200  includes spring arms  1204  and upstop arms  1202 . However, each spring arm  1204  of the dome  1200  includes a tab  1206  at its distal end. When used in the key  104 , the tabs  1206  may be the only portion of the spring arms  1204  that are inserted in the openings or recesses of the retention clips or the retention features of the key  104 . 
     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. Similarly, the terms convex (e.g., curved downward) and concave (e.g., curved upward) should be understood as referring to shapes of components viewed according to the orientations in the associated figures.

Metadata:
Filing Date: 20160524
Publication Date: 20180925
Grant Date: 20180925
Priority Date: 20160524
Inventors: WU, CHIA-CHI
GAO, ZHENG
Gao, Ming Gavin
WANG, PAUL X.
LEHMANN, Alex J.
XU, RICHARD
SILZ, Kenneth M.
LEE, CHIA-WEI
Assignee: APPLE INC
CPC Classifications: [{"code": "H01H13/52", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/85", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/785", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H13/85", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H13/78", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2227/026", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2217/004", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2227/022", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H3/122", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2227/036", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2215/004", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2227/036", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2227/026", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2227/022", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2217/004", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2215/004", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/78", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H3/122", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/52", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/785", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H13/85", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 60418108