PATENT DOCUMENT

Publication Number: US-10424446-B2
Application Number: US-201615154682-A
Country: US
Kind Code: B2

Title: Keyboard assemblies having reduced thickness and method of forming keyboard assemblies

Abstract:
Keyboard assemblies having reduced thicknesses and methods of forming the same. A keyboard assembly may include a printed circuit board (PCB) and a single membrane sheet adhered directly to the PCB. The single membrane sheet may substantially cover the PCB. The keyboard assembly may also include a group of dome switches coupled directly to the single membrane sheet. Another keyboard assembly may include a group of conductive pads and a group of membrane pads. Each of the group of membrane pads may be adhered directly to a corresponding one of the group of conductive pads. The keyboard assembly may also include a group of dome switches coupled directly to the membrane pads. Each of the group of dome switches may be coupled directly to a corresponding one of the group of membrane pads.

Claims:
We claim: 
     
       1. An electronic device comprising:
 a casing; and 
 a keyboard assembly housed at least partially within the casing, the keyboard assembly comprising:
 a printed circuit board (PCB) positioned within the casing; 
 a membrane layer attached to the PCB; 
 a switch housing affixed directly to the membrane layer or to the PCB; and 
 a dome switch coupled directly to the membrane layer. 
 
 
     
     
       2. The electronic device of  claim 1 , wherein an anisotropic conductive film is bonded to the PCB and the membrane layer is attached to the PCB by the anisotropic conductive film. 
     
     
       3. The electronic device of  claim 1 , wherein a film electrically couples the PCB and the membrane layer. 
     
     
       4. The electronic device of  claim 1 , wherein the membrane layer comprises one of:
 a single membrane sheet substantially covering the PCB; or 
 a group of membrane pads attached to the PCB. 
 
     
     
       5. The electronic device of  claim 1 , wherein the membrane layer is formed from a substantially flexible, electrically conductive material. 
     
     
       6. A keyboard assembly comprising:
 a printed circuit board (PCB); 
 a single membrane sheet substantially covering the PCB; 
 a conductive adhesive bonding the single membrane sheet to the PCB; and 
 a group of dome switches attached to the single membrane sheet, wherein the single membrane sheet comprises an electrical contact in electrical communication with the PCB. 
 
     
     
       7. The keyboard assembly of  claim 6 , wherein the conductive adhesive is a pressure sensitive adhesive. 
     
     
       8. The keyboard assembly of  claim 6 , wherein the group of dome switches is adhered to the single membrane sheet. 
     
     
       9. The keyboard assembly of  claim 6 , wherein:
 the electrical contact comprises a group of electrical contacts; and 
 a set of two distinct electrical contacts of the group of electrical contacts are formed below each dome switch of the group of dome switches. 
 
     
     
       10. The keyboard assembly of  claim 9 , wherein a single dome switch of the group of dome switches contacts one of the set of two distinct electrical contacts when the single dome switch is in a compressed state. 
     
     
       11. A keyboard assembly comprising:
 a printed circuit board (PCB) including a group of conductive pads; 
 a group of membrane pads, each of the group of membrane pads including a conductive spacer that is adhered directly to a corresponding one of the group of conductive pads; and 
 a group of dome switches, each of the group of dome switches coupled directly to a corresponding one of the group of membrane pads. 
 
     
     
       12. The keyboard assembly of  claim 11 , wherein:
 each of the group of membrane pads comprises:
 an outer conductive ring; and 
 an inner conductive ring within the outer conductive ring; and 
 
 the conductive spacer separates, and is concentric with, the outer conductive ring and the inner conductive ring. 
 
     
     
       13. The keyboard assembly of  claim 12 , wherein each of the group of conductive pads comprises:
 an outer conductive portion in contact with the outer conductive ring of a corresponding one of the group of membrane pads; and 
 an inner conductive portion spaced apart from and surrounded by the outer conductive portion, the inner conductive portion separated from the inner conductive ring and the conductive spacer of the membrane pad when a corresponding dome switch of the group of dome switches is in an uncompressed state. 
 
     
     
       14. The keyboard assembly of  claim 13 , wherein the conductive spacer of the membrane pad is in electrical communication with the outer conductive portion and the inner conductive portion of the conductive pad when the corresponding dome switch is in a compressed state. 
     
     
       15. The keyboard assembly of  claim 11 , wherein each of the group of membrane pads further comprises:
 an upper portion comprising a first electrical contact; and 
 a lower portion comprising two distinct electrical contacts; wherein 
 the lower portion is spaced apart from the upper portion when a corresponding dome switch of the group of dome switches is in an uncompressed state. 
 
     
     
       16. The keyboard assembly of  claim 15 , wherein the first electrical contact of the upper portion is displaced toward and contacts the two distinct electrical contacts of the lower portion when the corresponding dome switch is compressed. 
     
     
       17. The keyboard assembly of  claim 15 , wherein each upper portion is sealed to each corresponding lower portion at a perimeter of each of the group of membrane pads.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a nonprovisional patent application of and claims the benefit of 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,” the disclosure of which is hereby incorporated herein by reference in its entirety. 
    
    
     FIELD 
     The disclosure relates generally to input devices for electronic devices, and more particularly to keyboard assemblies having reduced thicknesses. 
     BACKGROUND 
     It is becoming more and more desirable within the industry to reduce the size and/or thickness of various electronic devices. As such, all components of an electronic device, including any keyboard assembly, may be reduced in size. As a result, the size and/or number of components of the keyboard likewise may be reduced. With a reduction in size, quantity and/or material used to form the various components, the strength, and ultimately the operational life of the component may be reduced. This may cause the operational life of the keyboard assembly and/or electronic device to be reduced as well. 
     SUMMARY 
     Generally, embodiments discussed herein are related to keyboard assemblies having reduced thicknesses. In a keyboard assembly, a dome switch may be disposed, coupled and/or affixed directly to a membrane layer of the keyboard assembly stack-up. Additionally, the membrane layer may be adhered directly to a printed circuit board (PCB) of the keyboard assembly stack-up. When compressed, the dome switch, membrane layer and PCB may all be in electrical connection and/or may cooperate to transmit or generate an electrical signal (e.g., input) for the keyboard assembly and/or electronic device utilizing the keyboard assembly. 
     The membrane layer may be a single component that substantially covers and/or is disposed over the PCB layer, and the various dome switches of the keyboard assembly may be disposed, coupled and/or affixed directly to distinct portions of the single membrane layer. Alternatively, each individual dome switch for each individual key assembly of the keyboard may be disposed, coupled and/or affixed directly to a corresponding membrane pad. The membrane pads may be adhered to a PCB layer or a corresponding conductive pad of the keyboard assembly stack-up. 
     By adhering a dome switch directly to the membrane layer and/or the membrane pad, and also adhering the membrane layer/pad(s) to the PCB, the overall size and/or thickness of the stack-up for the keyboard assembly may be reduced. Additionally, by coupling the dome switch directly to the membrane layer/pad, the dome switch may be more easily implemented, secured and/or installed in the stack-up of the keyboard assembly, which may reduce assembly time for the keyboard assembly. 
     One embodiment may take the form of an electronic device. The electronic device may comprise a casing, and a keyboard assembly housed at least partially within the casing. The keyboard assembly may comprise a printed circuit board (PCB) positioned within the casing, a membrane layer affixed directly to the PCB, and a dome switch coupled directly to the membrane layer. 
     Another embodiment may take the form of a keyboard assembly comprising a printed circuit board (PCB), and a single membrane sheet adhered directly to and substantially covering the PCB. The keyboard assembly may also comprise a group of dome switches coupled directly to the single membrane sheet. 
     An additional embodiment may take the form of a keyboard assembly comprising a group of printed circuit board (PCB) pads, and a group of membrane pads. Each of the group of membrane pads may be adhered directly to a corresponding one of the group of conductive pad. The keyboard assembly may also comprise a group of dome switches. Each of the group of dome switches may be coupled directly to a corresponding one of the group of membrane pads. 
     A further embodiment may take the form of a method for assembling a keyboard. The method may comprise coupling a dome switch directly to a membrane layer, adhering the membrane layer directly to a printed circuit board (PCB), and positioning a switch housing over the PCB to substantially surround the dome switch. The method may also comprise coupling a keycap to a hinge mechanism positioned adjacent the switch housing. The keycap may be positioned above the dome switch. 
    
    
     
       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  depicts an illustrative view of an electronic device including a keyboard assembly. 
         FIG. 2  depicts an illustrative exploded view of a key assembly of the keyboard assembly of  FIG. 1 . 
         FIG. 3  depicts an illustrative cross-section view of the key assembly of  FIG. 2  taken along line  3 - 3 . 
         FIG. 4  depicts an illustrative exploded view of a key assembly of the keyboard assembly of  FIG. 1 . 
         FIG. 5A  depicts an illustrative top view of the dome switch and the membrane pad of the key assembly of  FIG. 4 . 
         FIG. 5B  depicts an illustrative bottom view of the dome switch and the membrane pad of the key assembly of  FIG. 4 . 
         FIG. 6  depicts an illustrative cross-section view of the key assembly of  FIG. 4  taken along line  6 - 6  of  FIG. 4 . 
         FIG. 7  depicts an illustrative enlarged cross-section view of a portion of the key assembly of  FIG. 6 . 
         FIG. 8  depicts an illustrative top view of the membrane pad contacting the conductive pad of the key assembly of  FIG. 4 . 
         FIG. 9  depicts an illustrative enlarged cross-section view of a portion of the key assembly of  FIG. 6 . 
         FIG. 10  depicts a flow chart of an example process for assembling a keyboard for an electronic device. 
     
    
    
     It is noted that the drawings of the invention are not necessarily to scale. The drawings are intended to depict only typical aspects of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements between the drawings. 
     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. 
     The following disclosure relates generally to input devices for electronic devices, and more particularly to keyboard assemblies having reduced thicknesses. 
     In a keyboard assembly, a dome switch may be disposed, coupled and/or affixed directly to a membrane layer of the keyboard assembly stack-up. Additionally, the membrane layer may be adhered directly to a printed circuit board (PCB) of the keyboard assembly stack-up. When compressed, the dome switch, membrane layer and PCB may all be in electrical connection and/or may cooperate to transmit or generate an electrical signal (e.g., input) for the keyboard assembly and/or electronic device utilizing the keyboard assembly. 
     The membrane layer may be a single component that substantially covers and/or is disposed over the PCB layer, and the various dome switches of the keyboard assembly may be disposed, coupled and/or affixed directly to distinct portions of the single membrane layer. Alternately, each individual dome switch for each individual key assembly of the keyboard may be disposed, coupled and/or affixed directly to a corresponding membrane pad. The membrane pads may be adhered to a PCB layer or a corresponding conductive pad of the keyboard assembly stack-up. 
     By affixing a dome switch directly to the membrane layer and/or the membrane pad, and affixing the membrane layer/pad(s) to the PCB, the overall size and/or thickness of the stack-up for the keyboard assembly may be reduced. Additionally, by coupling the dome switch directly to the membrane layer/pad, the dome switch may be more easily implemented, secured and/or installed in the stack-up of the keyboard assembly, which may reduce assembly time for the keyboard assembly. 
     These and other embodiments are discussed below with reference to  FIGS. 1-10 . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these Figures is for explanatory purposes only and should not be construed as limiting. 
       FIG. 1  shows an illustrative view of an electronic device  100  including a keyboard assembly  200  having a reduced stack-up, and particularly having one or more dome switches directly connected to one or more membrane layers or pads that, in turn, may be connected directly to a printed circuit board. In a non-limiting example, as shown in  FIG. 1 , electronic device  100  may be a laptop computer. However, it is understood that electronic device  100  may be configured as any suitable electronic device that may utilize keyboard assembly  200 . Other embodiments can implement electronic device  100  differently, such as, for example, a desktop computer, a tablet computing device, a smartphone, a gaming device, a display, a digital music player, a wearable computing device or display, a health monitoring device, and so on. 
     Although discussed herein as a keyboard assembly, it is understood that the disclosed embodiments may be used in a variety of input devices used in various electronic devices. That is, keyboard assembly  200 , and the components of the assembly discussed herein, may be utilized or implemented in a variety of input devices for an electronic device including, but not limited to, buttons, switches, toggles, wheels, and the like. 
     Electronic device  100  may include a top case  102 . Top case  102  may take the form of an exterior, protective casing or shell for electronic device  100  and the various internal components (for example, keyboard assembly  200 ) of electronic device  100 . Top case  102  may be formed as a single, integral component or may have a group of distinct components coupled to one another, as discussed herein. Additionally, top case  102  may be formed from any suitable material that provides a protective casing or shell for electronic device  100  and the various components included in electronic device  100 . In non-limiting examples, top case  102  may be made from a metal, a ceramic, a rigid plastic or another polymer, a fiber-matrix composite, and so on. 
     Keyboard assembly  200  may be included within electronic device  100 . In a non-limiting example shown in  FIG. 1 , keyboard assembly  200  may include a set of keycaps  202  positioned within top case  102  of electronic device  100 . The set of keycaps  202  may partially protrude from top case  102  and each may be substantially surrounded by top case  102 . That is, the set of keycaps  202  of keyboard assembly  200  may extend beyond a surface of top case  102  and may be divided or separated by a portion of top case  102 . In the non-limiting example shown in  FIG. 1 , where electronic device  100  is a laptop computer, keyboard assembly  200  may be positioned within and/or may be received by electronic device  100 . Further, keyboard assembly  200  may be a distinct, standalone component, and may be in wired or wireless electronic communication with electronic device  100 . 
       FIG. 2  depicts an illustrative exploded view of keyboard assembly  200  shown in  FIG. 1 . Keyboard assembly  200  may be formed from the various layers of components, also referred to as a “stack-up” of layered components. Each layer and/or component of the stack-up of keyboard assembly  200  may provide different functionality and/or operations for electronic device  100  (see,  FIG. 1 ), as discussed herein. Although a single key stack-up of keyboard assembly  200  is shown in  FIG. 2 , it is understood that substantially all keys of keyboard assembly  200  may be formed from similar components and/or layers in a similar configuration and/or may function in a substantially similar manner as the single key stack-up shown in  FIG. 2  and discussed herein. 
     Keyboard assembly  200  may include a printed circuit board (PCB)  204  positioned below top case  102 . PCB  204  may be positioned within electronic device  100  casing formed by top case  102  and a bottom case (not shown in  FIG. 2 ) coupled to top case  102 . PCB  204  may be coupled to and/or rest on the bottom case and provide a rigid support structure for the various components forming keyboard assembly  200 . PCB  204  may include a set of electrical traces (not shown) formed therein or thereon. The traces may provide an electrical signal (e.g., input) to electronic device  100  when a keycap and/or dome switch is compressed, as discussed herein. PCB  204  may cover and/or may include a geometry substantially equal to the area of keyboard assembly  200  formed or positioned within top case  102  of electronic device  100  (see,  FIG. 1 ). 
     As shown in  FIG. 2 , a light source  206  may be positioned on PCB  204 . In a non-limiting example, light source  206  couples to and is in electrical communication with PCB  204 , such that PCB  204  provides power to illuminate light source  206 . As discussed herein, light source  206  may extend from PCB  204  through and/or into distinct layers or components of keyboard assembly  200  for providing light to illuminate keyboard assembly  200  and/or keycap  202 . Light source  206  may be formed from any suitable light source configured to illuminate key assembly and/or keycap  202  of keyboard assembly  200 . In a non-limiting example, light source  206  may be a light emitting diode (LED) coupled and/or affixed to PCB  204  of keyboard assembly  200 . 
     Keyboard assembly  200  may also include a membrane layer  207 . In a non-limiting example shown in  FIG. 2 , membrane layer  207  may be a single membrane sheet  208  that may substantially cover PCB  204 , although in other embodiments the membrane layer may include multiple sheets, films, or the like. Generally, single membrane sheet  208  may have a geometry substantially similar in surface area to PCB  204 , such that single membrane sheet  208  covers PCB  204  within the stack-up forming keyboard assembly  200 . In a non-limiting example, membrane layer  207  or single membrane sheet  208  may be a sensing membrane that includes at least one trace or sensor positioned on single membrane sheet  208 . As discussed herein, traces or sensors positioned on single membrane sheet  208  may be configured to detect or determine when keycap  202  of keyboard assembly  200  is actuated by a user, and subsequently provide an electrical signal (e.g., input) to PCB  204 , and ultimately to electronic device  100 . In a non-limiting example, single membrane sheet  208  may be formed from a substantially flexible, electrically conductive material including, but not limited to an indium tin oxide (no) layer. 
     As shown in  FIG. 2 , a dome switch  210  may be coupled directly to single membrane sheet  208 . The dome switch  210  may be laminated, adhered, or otherwise directly affixed to membrane sheet  208 . For example, a dome switch  210  may be positioned in or on ultraviolet (UV) glue deposited over single membrane sheet  208 , and the UV glue may be subsequently cured to affix dome switch  210  to single membrane sheet  208 . 
     As another example, single membrane sheet  208  and a group of dome switches  210  may be placed on a shaker table, and utilizing the motion or vibration of the shaker table, the group of dome switches may continuously move over single membrane sheet  208  until they are moved into a desired position. In another non-limiting example, a pick-and-place process may be used, where individual dome switches are placed in a desired location on the single membrane sheet  208 . 
     Dome switch  210  may be coupled and/or affixed directly to single membrane sheet  208  to aid in the assembly and/or installation process of single membrane sheet  208  and dome switch  210  within keyboard assembly  200 . By coupling dome switch  210  directly to single membrane sheet  208  prior to installing either component within keyboard assembly  200 , the dome switch  210  is absolutely affixed to single membrane sheet  208  of keyboard assembly  200 . Additionally, coupling dome switch  210  directly to single membrane sheet  208  prior to installation within keyboard assembly  200  simplifies placing the dome switch in a proper position, and eliminates the difficulty of attempting to install dome switch  210  within small spaces such as a switch housing of keyboard assembly  200 . 
     Dome switch  210  may be formed from any suitable material that is substantially flexible, durable and/or elastic. In a non-limiting example, dome switch  210  may be formed from rubber or another suitable elastomer. As discussed herein, keycap  202  may be compressed by a user input, and dome switch  210  in turn may be compressed, such that a portion of dome switch  210  contacts single membrane sheet  208  to form an electrical connection and/or input within electronic device  100 . 
     As shown in  FIG. 2 , single membrane sheet  208  (including dome switch  210 ) may be affixed or adhered directly to PCB  204 . In a non-limiting example, single membrane sheet  208 , having a substantially similar geometry or surface area as PCB  204 , may substantially cover PCB  204  by being affixed or adhered to PCB  204  using an adhesive layer  212 . As shown in  FIG. 2 , adhesive layer  212  may be positioned between single membrane sheet  208  to affix and/or directly couple single membrane sheet  208  to PCB  204 . In the non-limiting example, single membrane sheet  208 , including dome switch  210 , may be affixed or adhered directly to PCB  204  using an anisotropic conductive film that is adhered and/or bonded directly to single membrane sheet  208  and PCB  204 . Anisotropic conductive film may electrically couple PCB  204  to single membrane sheet  208 , and/or may provide an electrical conduit or intermediate electrical layer between PCB  204  and single membrane sheet  208 , such that single membrane sheet  208  and PCB  204  are in electrical communication. As discussed herein, when dome switch  210  is actuated or compressed by keycap  202 , an electrical circuit may be formed between single membrane sheet  208  and PCB  204  for providing an electrical signal and/or input to electronic device  100 . In another non-limiting example, a pressure sensitive adhesive may be positioned between single membrane sheet  208  and PCB  204  for adhering single membrane sheet  208  directly to PCB  204 . 
     Keyboard assembly  200  may also include a switch housing  218 . As shown in  FIG. 2 , switch housing  218  may be positioned above PCB  204  and may substantially surround dome switch  210 . In a non-limiting example, dome switch  210 , affixed or coupled directly to single membrane sheet  208 , may be positioned within an opening of switch housing  218 , such that switch housing  218  may substantially surround and/or substantially seal done switch  210  within keyboard assembly  200 . In the non-limiting example where membrane layer  207  is formed as single membrane sheet  208 , switch housing  218  may be affixed or adhered directly to single membrane sheet  208 . Switch housing  218  may be affixed or adhered directly to single membrane sheet  208  using housing adhesive layer  220 . Switch housing  218  may be formed from a substantially rigid material and provide support to the various components of keyboard assembly  200 , as well as protecting and/or sealing dome switch  210  within keyboard assembly  200 . Additionally, and as discussed herein, the material of switch housing  218  may be optically transparent to distribute and/or disperse the light emitted by light source  206  through keyboard assembly  200 . 
     A hinge mechanism  222  (as shown in  FIG. 4 ) of keyboard assembly  200  may substantially surround switch housing  218 . As shown in  FIG. 2 , switch housing  218  is positioned between and/or separates dome switch  210  coupled to single membrane sheet  208  and hinge mechanism  222 . Hinge mechanism  222  may be positioned above PCB  204  and may be affixed within keyboard assembly  200  by being coupled to switch housing  218  and/or PCB  204 . In a non-limiting example, hinge mechanism  222  may also be coupled to keycap  202  for providing support to keycap  202 . Hinge mechanism  222 , as shown in  FIG. 2 , may take the form of any suitable hinge mechanism  222  capable of moving keycap  202  from an uncompressed state to a compressed state, including but not limited to: a butterfly or V-shaped hinge mechanism, a scissor hinge mechanism, a telescoping hinge mechanism or a sliding hinge mechanism. 
     As shown in  FIGS. 1 and 2 , keycap  202  may protrude or extend at least partially through opening  104  formed in top case  102 , and may be interacted with by a user of electronic device  100 . Additionally, the various keycaps  202  of keyboard assembly  200  may be substantially surrounded and/or separated by web  106  of top case  102  of electronic device  100 . As discussed herein, when a user presses keycap  202 , keycap  202  and dome switch  210  of keyboard assembly  200  move from an uncompressed state to a compressed state to form an electrical connection and/or signal within electronic device  100 . 
       FIG. 3  shows a front cross-section view of keyboard assembly  200  of  FIG. 2  in an uncompressed state. Some layers or components, for example adhesive layer  212  and housing adhesive layer  220 , have been omitted for clarity. As shown in  FIG. 3 , light source  206  formed on PCB  204  may extend from PCB  204  into an opening formed in switch housing  218 . In a non-limiting example where membrane layer  207  is formed as single membrane sheet  208  (as opposed to from multiple sheets and/or films and/or adhesives), light source  206  may extend through an opening formed in single membrane sheet  208 , and into the opening of switch housing  218  configured to receive light source  206 . By positioning light source  206  substantially within switch housing  218 , light source  206  may illuminate keycap  202  of keyboard assembly  200 . 
     Single membrane sheet  208  of keyboard assembly  200  may also include two electrical traces or contacts  224 . As shown in  FIG. 3 , electrical contacts  224  may be positioned below dome switch  210  and may be coupled to and/or embedded directly within single membrane sheet  208 . Electrical contacts  224  of single membrane sheet  208  may be in electrical contact and/or may be in electrical communication with contacts or traces formed within and/or on PCB  204  (not shown). In a non-limiting example, when keycap  202  and/or dome switch  210  are in a compressed state, a portion of dome switch  210  may move toward single membrane sheet  208  and may contact electrical contacts  224  formed in single membrane sheet  208 . When the dome switch  210  contacts the electrical contacts  224 , it completes an electrical circuit between single membrane sheet  208  and PCB  204 , and an electrical input or other signal is provided to electronic device  100 . 
     As shown in  FIG. 3 , PCB  204  may have an aperture  226  formed therein. In a non-limiting example, aperture  226  may be formed in PCB  204 , and may be centrally aligned with dome switch  210  coupled directly to single membrane sheet  208 . When dome switch  210  is compressed by keycap  202  and/or in a compressed state, and contacts electrical contacts  224  to complete an electrical circuit within keyboard assembly  200 , dome switch  210  may also deflect single membrane sheet  208 . As a result, a portion of single membrane sheet  208  may deflect into aperture  226  of PCB  204 . In allowing a portion of single membrane sheet  208  to deflect into aperture  226  of PCB  204 , the tactile feel to a user compressing keycap  202  may have a less severe or sudden end point. Additionally, by allowing a portion of single membrane sheet  208  to deflect into aperture  226  of PCB  204 , dome switch  210  and/or keycap  202  may have a greater distance of travel between an uncompressed and compressed state, without requiring additional height, thickness and/or z-space for keyboard assembly  200 . 
       FIG. 4  depicts an illustrative exploded view of keyboard assembly  200  including distinct components, layers and/or features. The distinct components, layers and/or features are identified in detail below. However, it is understood that similarly named components or similarly numbered components may function in a substantially similar fashion, may include similar materials and/or may include similar interactions with other components. Redundant explanation of these components has been omitted for clarity. 
     As shown in  FIG. 4 , PCB  204  may include conductive pads  228 . In a non-limiting example, PCB  204  may include a plurality of conductive pads  228 , where each conductive pad  228  corresponds to a single key assembly and/or keycap  202  of keyboard assembly  200 . Additionally, and as discussed herein, conductive pad  228  may correspond to and/or may be in direct contact with individual membrane pads  230  forming membrane layer  207  of keyboard assembly  200 . Conductive pads  228  may form an electrical conduit and/or may electrically couple membrane layer  207  (e.g., membrane pad  230 ) to PCB  204  to provide electrical input and/or signals to electronic device  100 , when keycap  202  and/or dome switch  210  is compressed, as discussed herein. 
     In keyboard assembly  200  shown in  FIG. 4 , membrane layer  207  may be formed from membrane pad  230 . In a non-limiting example, membrane pad  230 , similar to conductive pad  228  may be specific to an individual keycap  202  of keyboard assembly  200 . As such, membrane layer  207  may not be a single membrane pad, similar to that of single membrane sheet  208  of  FIGS. 2 and 3 , but rather, membrane layer  207  may be formed from a group of membrane pads  230 , where each membrane pad  230  corresponds to an individual keycap  202  of keyboard assembly  200 . Membrane pad  230  may be adhered directly to conductive pad  228  of PCB  204  in similar fashions as discussed herein with respect to single membrane sheet  208  and PCB  204  (see,  FIG. 2 ). Although not shown in  FIG. 4 , it is understood that adhesive layer  212  may be positioned between membrane pad  230  and PCB  204  to affix adhere membrane pad  230  directly to conductive pads  228  of PCB  204 . Additionally, dome switch  210  may be coupled directly to membrane pad  230  in similar fashions as discussed herein with respect to dome switch  210  and single membrane sheet  208  (see,  FIG. 2 ). Portions of membrane pad  230  may be formed from a substantially flexible, electrically conductive material including, but not limited to an indium tin oxide (no) layer. Additionally, and as discussed herein in detail, distinct portions of membrane pad  230  that may contact conductive pad  228  may be formed from various materials having distinct physical and/or electrically conductive properties. 
     As shown in  FIG. 4 , membrane pad  230  corresponding to conductive pad  228  and a single keycap  202  of keyboard assembly  200  may be substantially surrounded by switch housing  218 . In a non-limiting example, the perimeter of membrane pad  230  may not extend beyond the opening formed within switch housing  218 . As such, switch housing  218  may substantially surround and seal dome switch  210  as well as membrane pad  230 . Additionally, because membrane pad  230  does not extend below switch housing  218 , switch housing  218  may be adhered directly to PCB  204  via housing adhesive layer  220 . 
       FIGS. 5A and 5B  depict various views of dome switch  210  and membrane layer  207  formed as membrane pad  230 . As shown in  FIGS. 5A and 5B , and as discussed herein, dome switch  210  may be adhered directly to membrane pad  230 . Dome switch  210  may be adhered directly to membrane pad  230  prior to installing dome switch  210  and membrane pad  230  within keyboard assembly  200  to improve the assembly process and/or to avoid assembly and/or functionality defects within keyboard assembly  200 . That is, dome switch  210  may be adhered directly to membrane pad  230  prior to adhering membrane pad  230  directly to conductive pad  228  and/or PCB  204  to ease the assembly process and/or ensure dome switch  210  is properly aligned on membrane pad  230  before aligning and coupling membrane pad  230  to PCB  204 . 
       FIG. 5B  depicts a bottom view of dome switch  210  and membrane pad  230 . In a non-limiting example, membrane pad  230  may be formed from an outer conductive ring  232 , an intermediate conductive spacer  234 , and an inner conductive ring  236 . Each of outer conductive ring  232 , intermediate conductive spacer  234  and inner conductive ring  236  may be concentric with one another, such that intermediate conductive spacer  234  is concentric with and surrounded by outer conductive ring  232 , and inner conductive ring  236  is concentric with and surrounded by intermediate conductive spacer  234  and/or outer conductive ring  232 . 
     Outer conductive ring  232  and inner conductive ring  236  may be formed from substantially similar material (e.g., indium tin oxide (ITO)) and/or may include similar physical (e.g., flexible) and electrical properties. Intermediate conductive spacer  234  may be formed from a distinct material than outer conductive ring  232  and/or inner conductive ring  236 . In a non-limiting example, intermediate conductive spacer  234  may be formed from an adhesive layer having electrically conductive properties. In the non-limiting example where intermediate conductive spacer  234  is formed from an electrically conductive adhesive layer, intermediate conductive spacer  234  may aid in adhering membrane pad  230  to PCB  204  and/or conductive pad  228 , as well as forming an electrical conduit and/or electrically communicating membrane pad  230  to PCB  204 , as discussed herein. In another non-limiting example, intermediate conductive spacer  234  may be formed from a substantially flexible material having electrical properties. This material may be distinct from or substantially similar to the material forming outer conductive ring  232  and/or inner conductive ring  236 . 
     Intermediate conductive spacer  234  and/or inner conductive ring  236  of membrane pad  230  may be raised above outer conductive ring  232 . That is, in a non-limiting example, intermediate conductive spacer  234  and/or inner conductive ring  236  may not be in planar alignment with outer conductive ring  232  of membrane pad  230 . As such, and as discussed herein, when membrane pad  230  is coupled to conductive pad  228 , only inner conductive ring  236  may contact conductive pad  228 , while intermediate conductive spacer  234  and/or inner conductive ring  236  are positioned above and/or spaced apart from conductive pad  228 . Additionally as discussed herein, when keycap  202  and/or dome switch  210  are compressed by a user&#39;s input, intermediate conductive spacer  234  and/or inner conductive ring  236  may be deflected to contact conductive pad  228  of PCB  204  to form an electrical input or signal within electronic device  100 . 
       FIG. 6  shows a front cross-section view of keyboard assembly  200  of  FIG. 4  in an uncompressed state. As shown in  FIG. 6 , light source  206  formed on PCB  204  may extend from PCB  204  into an opening formed in switch housing  218 . In the non-limiting example where membrane layer  207  is formed as membrane pad  230 , light source  206  may extend from PCB  204  into switch housing  218 . That is, and distinct from  FIG. 3 , membrane pad  230  does not extend beyond or below switch housing  218 , and as a result, light source  206  may not pass through membrane pad  230 , but rather extends directly from PCB  204  to the opening of switch housing  218  configured to receive light source  206 . 
     As shown in  FIG. 7 , conductive pad  228  may include distinct conductive portions  229   a ,  229   b . In a non-limiting example shown in  FIGS. 6 and 7 , conductive pad  228  may include an outer conductive portion  229   a , and an inner conductive portion  229   b  surrounded by outer conductive portion  229   a . Additionally in the non-limiting example, inner conductive portion  229   b  may be spaced apart from and/or may not be in contact with outer conductive portion  229   a  of conductive pad  228 . Outer conductive portion  229   a  and inner conductive portion  229   b  may be electrical contacts or traces for PCB  204  for forming an electrical input or signal within electronic device  100 . As discussed herein, outer conductive portion  229   a  and inner conductive portion  229   b  of conductive pad  228  may contact the various portions (e.g., outer conductive ring  232 , intermediate conductive spacer  234 , and inner conductive ring  236 ) of membrane pad  230  to form an electrical input or signal within electronic device  100 , when keycap  202  and/or dome switch  210  is compressed. 
     As shown in  FIG. 7 , when keycap  202  and/or dome switch  210  of keyboard assembly  200  is in an uncompressed state, a gap or space  237  may exist between membrane pad  230  and conductive pad  228 . The space  237  may specifically be formed between inner conductive portion  229   b  of conductive pad  228  and intermediate conductive spacer  234  and/or inner conductive ring  236  of membrane pad  230  when dome switch  210  is uncompressed. As discussed herein with respect to  FIG. 5B , space  237  may exist between conductive pad  228  and portions of membrane pad  230  as a result of intermediate conductive spacer  234  and/or inner conductive ring  236  being recessed within and/or being out of planar alignment with outer conductive ring  232  of membrane pad  230 . As shown in  FIG. 7 , outer conductive ring  232  of membrane pad  230  may be in contact with outer conductive portion  229   a  of conductive pad  228  formed on PCB  204 . 
     However, in a compressed state of keycap  202  and/or dome switch  210  of keyboard assembly  200 , space  237  may be closed when a portion of dome switch  210  contacts membrane pad  230 , and subsequently deflects membrane pad  230  into conductive pad  228 . That is, when dome switch  210  is compressed by keycap  202 , dome switch  210  may contact, deflect and/or flex membrane pad  230  toward PCB  204  to contact conductive pad  228  and/or substantially close or fill space  237  formed between membrane pad  230  and conductive pad  228 . Because of the deflection of membrane pad  230 , intermediate conductive spacer  234  and/or inner conductive ring  236  may contact inner conductive portion  229   b  of conductive pad  228 . When intermediate conductive spacer  234  and/or inner conductive ring  236  contacts inner conductive portion  229   b  of conductive pad  228 , the various portions of membrane pad  230  and conductive pad  228  may be in electrical contact and may complete an electrical circuit within keyboard assembly  200 . 
       FIG. 8  depicts a top view of membrane pad  230  and conductive pad  228  (shown in phantom), and illustrates the geometric relationship of each portion of membrane pad  230  with respect to conductive pad  228 . In a non-limiting example shown in  FIG. 8 , outer conductive ring  232  of membrane pad  230  may overlap and/or cover a portion of outer conductive portion  229   a  of conductive pad  228 , and inner conductive ring  236  of membrane pad  230  may overlap and/or cover a portion of inner conductive portion  229   b  of conductive pad  228 . Additionally in the non-limiting example, intermediate conductive spacer  234  may overlap and/or cover a portion of both outer conductive portion  229   a  and inner conductive portion  229   b  of conductive pad  228 . 
     As discussed herein, when dome switch  210  is in an uncompressed state, only outer conductive ring  232  of membrane pad  230  may contact outer conductive portion  229   a  of conductive pad  228 . However, in a compressed state of dome switch  210 , inner conductive ring  236  of membrane pad  230  may contact inner conductive portion  229   b  of conductive pad  228 . Additionally, when dome switch  210  is compressed, intermediate conductive spacer  234  may contact both outer conductive portion  229   a  and inner conductive portion  229   b  of conductive pad  228 , and may bridge the electrical gap between the various portions of membrane pad  230  and conductive pad  228 . 
     Briefly returning to  FIG. 7 , dome switch  210  may include a venting hole  238 . Venting hole  238  may expel air from underneath dome switch  210  when dome switch  210  is compressed by keycap  202 . By expelling air from the space between dome switch  210  and membrane layer  207 , the air pressure under dome switch  210  may be maintained within keyboard assembly  200 . 
       FIG. 9  depicts another non-limiting example of membrane pad  230 . In the non-limiting example, membrane pad  230  may include an upper portion  240   a  and a lower portion  240   b  positioned opposite upper portion  240   a . As shown in  FIG. 9 , lower portion  240   b  may be positioned directly adjacent to and/or may be directly adhered to PCB  204 . Upper portion  240   a  is positioned above lower portion  240   b  and extends toward dome switch  210 . Additionally as shown in  FIG. 9 , upper portion  240   a  and lower portion  240   b  may be sealed on a periphery or perimeter of membrane pad  230 . As a result, the space formed between upper portion  240   a  and lower portion  240   b , and the electrical contacts positioned therein, as discussed below, may be sealed and/or protected from contaminants. 
     As shown in  FIG. 9 , upper portion  240   a  may include a first electrical contact  242 , and lower portion  240   b  may include two distinct electrical contacts  244 . In an uncompressed state of dome switch  210 , first electrical contact  242  and two distinct electrical contacts  244  may be spaced apart from each other, as shown in  FIG. 9 . However, when keycap  202  and/or dome switch  210  is compressed, first electrical contact  242  and/or upper portion  240   a  of membrane pad  230  may move toward distinct electrical contacts  244  and/or lower portion  240   b  until first electrical contact  242  contacts distinct electrical contacts  244 . When first electrical contact  242  contacts distinct electrical contacts  244 , an electrical circuit is completed within membrane pad  230 , and consequently an electrical circuit is completed with PCB  204  that is in electrical communication with the electrical contacts  242 ,  244  of membrane pad  230  via contacts or traces formed on PCB  204 . As similarly discussed herein, the completion of the electrical circuit between membrane pad  230  and PCB  204  provides an electrical input and/or signal to electronic device  100 . 
       FIG. 10  depicts an example process for assembling a keyboard. Specifically,  FIG. 10  is a flowchart depicting one example process  1000  for assembling a keyboard for an electronic device. In some cases, the process may be used to form one of the various embodiments of the keyboard assemblies, as discussed above with respect to  FIGS. 2-9 . 
     In operation  1002 , a dome switch may be directly coupled to a membrane layer of the keyboard assembly. The coupling of the dome switch directly to the membrane layer may include adhering or otherwise affixing the dome switch to the membrane layer, or laminating the dome switch to the membrane layer. When the dome switch is adhered to the membrane layer, the adhering may also include depositing ultraviolet (UV) glue between the dome switch and the membrane layer, and subsequently curing the UV glue deposited between the dome switch and the membrane layer. 
     The membrane layer of the keyboard assembly may take the form of various embodiments, including a single membrane sheet that may substantially cover a printed circuit board (PCB) of the keyboard assembly. When the membrane layer is configured as a single membrane sheet, the dome switch may be affixed directly to the single membrane sheet. The membrane layer may also take the form of a membrane pad that may correspond to the dome switch. When the membrane layer is configured as a membrane pad, the dome switch may be affixed directly to the membrane pad. 
     In operation  1004 , the membrane layer may be directly adhered to a PCB of the keyboard assembly. Specifically, the membrane layer, and the dome switch coupled to the membrane layer, may be adhered directly to the PCB. In a non-limiting example, the adhering of the membrane layer to the PCB may also include bonding an anisotropic conductive film between the membrane layer and the PCB, to bond the membrane layer to the PCB. 
     In operation  1006 , a switch housing may be positioned over the PCB. Specifically, the housing may be positioned over the PCB and/or adjacent the PCB and/or the membrane layer. The housing positioned over the PCB may substantially surround the dome switch coupled directly to the membrane layer. The operation of positioning the switch housing over the PCB may also include adhering (or otherwise affixing) the housing to the PCB and/or membrane layer. Specifically, where the membrane layer is configured as a single membrane sheet, the housing may be adhered directly to the single membrane sheet. Where the membrane layer is configured as a membrane pad, the housing may be adhered directly to the PCB. The housing adhered directly to the PCB may substantially surround the membrane pad as well as the dome switch. 
     In operation  1008 , a keycap may be coupled to a hinge mechanism. The hinge mechanism may be positioned adjacent to and/or may substantially surround the housing. Additionally, the keycap may be positioned above the dome switch coupled directly to the membrane layer, and the housing as well. The keycap may be releasably coupled to the hinge mechanism, which may be configured to move the keycap to compress the dome switch to form an electrical connection within the keyboard assembly. 
     In a keyboard assembly, a dome switch may be disposed, coupled and/or affixed directly to a membrane layer of the keyboard assembly stack-up. Additionally, the membrane layer may be adhered directly to a printed circuit board (PCB) of the keyboard assembly stack-up. When compressed, the dome switch, membrane layer and PCB may all be in electrical connection and/or may form an electrical signal (e.g., input) for the keyboard assembly and/or electronic device utilizing the keyboard assembly. In one embodiment, the membrane layer may be a single component that substantially covers and/or is disposed over the PCB layer, and the various dome switches of the keyboard assembly may be disposed, coupled and/or affixed directly to distinct portions of the single membrane layer. In another embodiment, each individual dome switch for each individual key assembly of the keyboard may be disposed, coupled and/or affixed directly to a corresponding membrane pad. The membrane pad may be adhered to a PCB layer or a corresponding conductive pad of the keyboard assembly stack-up. By affixing the dome switch directly to the membrane layer and/or the membrane pad, and affixing the membrane layer/pad to the PCB, the overall size and/or thickness of the stack-up for the keyboard assembly is reduced. Additionally, by coupling the dome switch directly to the membrane layer/pad, the dome switch may be more easily implemented, secured and/or installed in the stack-up of the keyboard assembly, which may reduce assembly time for the keyboard assembly. 
     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.

Metadata:
Filing Date: 20160513
Publication Date: 20190924
Grant Date: 20190924
Priority Date: 20150513
Inventors: LEONG, Craig C.
ZERCOE, BRADFORD J.
LA, THAI Q.
CAO, ROBERT Y.
LEHMANN, Alex J.
MATHEW, DINESH C.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01H13/88", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/7065", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H2203/028", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2231/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/807", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2215/006", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2205/026", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1662", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H3/125", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2203/028", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2205/026", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H3/125", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/702", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H2215/006", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2215/006", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/7065", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01H2205/026", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2231/002", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H13/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H3/125", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01H2203/028", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1662", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/88", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/807", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/702", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H13/702", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 56080476