Patent Publication Number: US-8984737-B2

Title: Method of manufacturing keycaps of keys of a keyboard

Description:
TECHNICAL FIELD 
     The present disclosure relates to electronic devices including keyboards. 
     BACKGROUND DISCUSSION 
     Electronic devices, including portable electronic devices, have gained widespread use and may provide a variety of functions including, for example, telephonic, electronic messaging and other personal information manager (PIM) application functions. Portable electronic devices include, for example, several types of mobile stations such as simple cellular telephones, smart telephones, wireless personal digital assistants (PDAs), and laptop computers with wireless 802.11 or Bluetooth capabilities. 
     Portable electronic devices such as PDAs or smart phones may include keypads or keyboards comprising keys associated with characters. Keypads and keyboards may be illuminated by backlighting the keycaps such that the characters displayed on the keys are visible in low light conditions. Metal keycaps may be utilized for such keyboards. Metal keycaps generally include plastic-filled cut outs in the shape of characters to facilitate backlighting. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present application will now be described, by way of example only, with reference to the attached Figures, wherein: 
         FIG. 1  is a simplified block diagram of one example of a portable electronic device in accordance with the present disclosure; 
         FIG. 2  is a front view of an example of a portable electronic device in accordance with the disclosure; 
         FIG. 3  is a flow chart illustrating a method of producing a keycap in accordance with the disclosure; 
         FIG. 4A  through  FIG. 4C  are example cross sectional views illustrating the method of producing a keycap in accordance with the disclosure; 
         FIG. 5A  and  FIG. 5B  are a perspective view and a backside view, respectively, of an example of a body of a keycap during the method of production in accordance with the disclosure; 
         FIG. 6  is a perspective view of a cutaway of the example of the body of the keycap shown in  FIG. 5A  and  FIG. 5B ; 
         FIG. 7A  and  FIG. 7B  are a perspective view and a backside view, respectively, of the body of a keycap during the method of production in accordance with the disclosure; 
         FIG. 8A  and  FIG. 8B  are a perspective view and a front side view of the keycap in accordance with the disclosure; 
         FIG. 9  is an example cross sectional view illustrating the method of producing a keycap in accordance with the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following describes an electronic device and a method for producing a keycap of a keyboard of a portable electronic device that includes removing material from a backside of a body of the keycap to form a cavity in a shape associated with a character, filling the cavity with a fill material, and removing material from a front side of the body to expose the fill material on a front surface of the keycap. 
     For simplicity and clarity of illustration, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. Numerous details are set forth to provide an understanding of the examples described herein. The examples may be practiced without these details. In other instances, well-known methods, procedures, and components are not described in detail to avoid obscuring the examples described. The description is not to be considered as limited to the scope of the examples described herein. 
     The disclosure generally relates to an electronic device, such as a portable electronic device. Examples of portable electronic devices include mobile, or handheld, wireless communication devices such as pagers, cellular phones, cellular smart-phones, wireless organizers, personal digital assistants, wirelessly enabled notebook computers, tablet computers, mobile internet devices, and so forth. The portable electronic device may be a portable electronic device without wireless communication capabilities, such as handheld electronic games, digital photograph albums, digital cameras, media players, e-book readers, and so forth. 
     A block diagram of an example of a portable electronic device  100  is shown in  FIG. 1 . The portable electronic device  100  includes multiple components, such as a processor  102  that controls the overall operation of the portable electronic device  100 . Communication functions, including data and voice communications, are performed through a communication subsystem  104 . Data received by the portable electronic device  100  is decompressed and decrypted by a decoder  106 . The communication subsystem  104  receives messages from and sends messages to a wireless network  150 . The wireless network  150  may be any type of wireless network, including, but not limited to, data wireless networks, voice wireless networks, and networks that support both voice and data communications. A power source  142 , such as one or more rechargeable batteries or a port to an external power supply, powers the portable electronic device  100 . 
     The processor  102  interacts with other components, such as Random Access Memory (RAM)  108 , memory  110 , a display  112 , a keyboard  120 , an auxiliary input/output (I/O) subsystem  124 , a data port  126 , a speaker  128 , a microphone  130 , short-range communications  132 , and other device subsystems  134 . In the example illustrated in  FIG. 1 , the display  112  is part of a touch-sensitive display  118 . Input via a graphical user interface may be provided utilizing the touch-sensitive display  118  or any other suitable device. User-interaction with a graphical user interface may be performed through a touch-sensitive overlay  114  which overlies the display  112 . The processor  102  interacts with the touch-sensitive overlay  114  via an electronic controller  116 . Information, such as text, characters, symbols, images, icons, and other items that may be displayed or rendered on a portable electronic device, is displayed on the touch-sensitive display  118  via the processor  102 . The processor  102  may interact with an accelerometer  136  that may be utilized to detect direction of gravitational forces or gravity-induced reaction forces. 
     The processor  102  also interacts with a navigation device  140  such as a touch-sensitive track pad, a trackball, an optical joystick, and so forth, to interface with a user to provide input. The navigation device  140  may be utilized, for example, to navigate or scroll through information on a display, control a cursor or other indicator, edit information, and so forth. On the portable electronic device  100 , the navigation device  140  may be located, for example, between the display  112  and the keyboard  120 . 
     To identify a subscriber for network access, the portable electronic device  100  may utilize a Subscriber Identity Module or a Removable User Identity Module (SIM/RUIM) card  138  for communication with a network, such as the wireless network  150 . Alternatively, user identification information may be programmed into memory  110 . 
     The portable electronic device  100  includes an operating system  146  and software programs, applications, or components  148  that are executed by the processor  102  and are typically stored in a persistent, updatable store such as the memory  110 . Additional applications or programs may be loaded onto the portable electronic device  100  through the wireless network  150 , the auxiliary I/O subsystem  124 , the data port  126 , the short-range communications subsystem  132 , or any other suitable subsystem  134 . 
     A received signal such as a text message, an e-mail message, or web page download is processed by the communication subsystem  104  and input to the processor  102 . The processor  102  processes the received signal for output to the display  112  and/or to the auxiliary I/O subsystem  124 . A subscriber may generate data items, for example e-mail messages, which may be transmitted over the wireless network  150  through the communication subsystem  104 . For voice communications, the overall operation of the portable electronic device  100  is similar. The speaker  128  outputs audible information converted from electrical signals, and the microphone  130  converts audible information into electrical signals for processing. 
     The touch-sensitive display  118  may be any suitable touch-sensitive display, such as a capacitive, resistive, infrared, surface acoustic wave (SAW) touch-sensitive display, strain gauge, optical imaging, dispersive signal technology, acoustic pulse recognition, and so forth, as known in the art. A capacitive touch-sensitive display includes a capacitive touch-sensitive overlay  114 . The overlay  114  may be an assembly of multiple layers in a stack including, for example, a substrate, a ground shield layer, a barrier layer, one or more capacitive touch sensor layers separated by a substrate or other barrier, and a cover. The capacitive touch sensor layers may be any suitable material, such as patterned indium tin oxide (ITO). 
     One or more touches, also known as touch contacts or touch events, may be detected by the touch-sensitive display  118 . The processor  102  may determine attributes of the touch, including a location of a touch. Touch location data may include an area of contact or a single point of contact, such as a point at or near a center of the area of contact. When a touch begins, one or more signals are provided to the controller  116  and the origin of the touch may be determined from the signals. The origin may be a point or an area, for example. Signals may be provided to the controller at regular intervals in time for a touch, also known as sampling, such that changes in location of the touch may be detected. A touch may be detected from any suitable input member, such as a finger, thumb, appendage, or other objects, for example, a stylus, pen, or other pointer, depending on the nature of the touch-sensitive display  118 . The controller  116  and/or the processor  102  may detect a touch by any suitable input member on the touch-sensitive display  118 . Multiple simultaneous touches may be detected. 
     One or more gestures may also be detected by the touch-sensitive display  118 . A gesture, such as a swipe, also known as a flick, is a particular type of touch on a touch-sensitive display  118  that begins at an origin point and continues to an end point. A gesture may be identified by attributes of the gesture, including the origin point, the end point, the distance travelled, the duration, the velocity, and the direction, for example. A gesture may be long or short in distance and/or duration. Two points of the gesture may be utilized to determine a direction of the gesture. A hover may be a touch at a location that is generally unchanged over a period of time or is associated with the same selection item for a period of time. 
     The keyboard  120  is separate and spaced from the touch-sensitive display  118 . The keyboard  120  is a physical keyboard that includes keycaps  204  ( FIG. 2 ). The keyboard  120  may include mechanical keys that provide tactile feedback to a user when the keycaps  204  are depressed. Such mechanical keys may include, for example, mechanical switches disposed under the keycaps  204 . Alternatively, the keyboard  120  may include other actuators disposed under the keycaps  204  to provide tactile feedback. 
     A front view of an example of the electronic device  100  is shown in  FIG. 2 . The electronic device  100  includes a housing  202  in which the display  112 , the navigation device  140 , and the keyboard  120  are disposed. The housing  202  is utilized to enclose components such as the components shown in  FIG. 1 . In the example illustrated in  FIG. 2 , the keyboard is a full keyboard, such as a QWERTY, QWERTZ, or AZERTY keyboard. Alternatively, the keyboard  120  may be a reduced keyboard that includes fewer keys than a full keyboard, such as a twelve-button telephone keypad. 
     Each keycap  204  may be associated with one or more characters including letters, numbers, and/or symbols. Each keycap  204  includes an indication or indications, on the keycap  204 , of the character or characters associated with the keycap  204 . 
     The keyboard  120  may be backlit using LEDs, or any other suitable light source, located between a back of the housing  202  and the keycaps  204 . Light from the light source shines through the keycaps  204  to facilitate utilizing the keyboard  120  in low external light conditions. The keycaps  204  may be selectively backlit such that some keycaps  204  are backlit while other keycaps  204  are not. 
     Each keycap  204  may comprise a body and fill material. The bodies of the keycaps  204  may include cutouts in the shape of characters that are filled with the fill material. The fill material is discernable from the material of the body such that the fill material imbedded in the body indicates the character or characters associated with the keycap  204  by providing a display of the character on a front surface of the keycap  204 . 
     The fill material may be any material suitable for filling the cutouts in the body. For example, the fill material may be a thermoplastic that is solid at room temperature and a liquid when heated to facilitate filling the cutouts in the bodies of the keycaps  204 . Alternatively, the fill material may be a thermoset plastic. The fill material of the keycaps  204  may be a transparent or translucent material, such as plastic, and the bodies of the keycaps  204  may be an opaque material, such as metal or plastic. During backlighting, light from the light source passes through the fill material such that the characters associated with the keycaps  204  are illuminated. Alternatively, the fill material may be opaque while the bodies of the keycaps  204  are translucent, or the bodies and the fill material may be both opaque or both translucent. 
     A flowchart illustrating a method of producing the keycaps  204  is shown in  FIG. 3 . A body may be used to produce a single keycap  204  or two or more keycaps  204  joined together. 
     A character cavity is formed in the body by removing material from the backside of the body, also referred to herein as a first side, at  302 . Material may be removed from the body using any suitable method. For example, material may be removed by etching, burning, or machining. The character cavity may extend partially through the thickness of the body toward the front side of the body, without extending through to the front side, or second side. The character cavity may be shaped, on the backside of the body, to provide a mirror image of characters associated with the keycap  204  such that the characters are correctly oriented for display on the front surface of the keycap  204 . 
     A frame may be formed when material is removed from the backside of the body. The frame may extend around the character cavity to produce a frame cavity. The frame cavity extends into the body, toward the front side, to a depth that is less than the depth of the character cavity. The frame reduces the amount of light that is leaked around the backside of the keycap  204  when the keycap  204  is assembled into a backlit keyboard  120 . 
     As will be described in further detail below, bore holes may by formed when material is removed from the backside of the body. Bore holes may extend into the body from the bottom of the character cavity through to the front side of the body. Several bore holes may be distributed throughout the character cavity. For example, bore holes may be spaced at regular intervals along the bottom of the character cavity. Air may escape into the bore holes during filling of the character cavity, reducing the chance of formation of air pockets in the fill material exposed on the front surface of the keycap  204 . 
     The character cavity in the backside of the keycap  204  is filled with a fill material at  304 . For a body that includes a frame, filling may include filling the character cavity only, or may include filling the character cavity and the frame cavity. The character and frame cavities may be filled using any suitable method. For example, the fill material may be heated to a liquid state and poured or injected into the character cavity and, optionally, the frame cavity on the backside of the body. 
     The character cavity and frame cavity may be filled to form a thick layer covering the backside of the body and the excess fill material is removed by any suitable method, such as etching, burning, or machining, to produce a thin keycap  204 . Alternatively, the character cavity and, optionally, the frame cavity may be filled such that the backside of the body is covered with fill material to the desired thickness, without excess fill material being applied. 
     Body and fill material is removed from the front side, or second side, of the body to expose the fill material on the front surface of the keycap at  306 . Body and fill material may be removed from the front surface of the body using any suitable method. For example, body and fill material may be removed by etching, burning, or machining. Body and fill material may be removed from the front side of the body to provide a keycap with uniform thickness. Alternatively, body and fill material may be removed from the front surface of the body to provide a keycap with non-uniform thickness such that the front surface of the keycap includes a three dimensional structure. The three dimensional structure on the front surface of the keycap may include, for example, a non-planar or domed surface. 
     The surfaces of the keycaps  204  may be polished at  308 . The keycaps  204  may be polished utilizing any suitable method. The keycaps  204  are assembled into the keyboard of the portable electronic device  100  at  310 . Assembling the keycaps  204  may include separating the keycaps  204  in the case that two or more keycaps  204  are produced on a single body. Alternatively, the keycaps  204  may be separated prior to polishing at  308 . 
       FIG. 4A  through  FIG. 4C  are examples illustrating the method of producing a keycap  204 . A cross section of a body  402  after material has been removed from a backside  404  at  302  and before the body is filled with a fill material  406  at  304  is illustrated in  FIG. 4A . The back surface of the body  402 , prior to material being removed, is illustrated by the dotted line  408 . As described above, a frame  410  and a cavity  412  are formed in the body  402  by removing material from the backside  404  of the body  402 . The cavity  412  includes a plurality of bore holes  414  that extend from a bottom  416  of the cavity  406  through to a front side  418  of the body  402 . The frame  410  extends around the backside of the keycap and may enclose the cavity  412 . The frame  410  is utilized to reduce the amount of light leaked when the keycap  204  is backlit. The frame  410  also facilitates retention of fill material  406  when the fill material  406  is heated and poured or injected into the cavity  412  and frame  410 . 
     The cavity  412  may have the shape of a single character, or two or more separate characters. The character may include an island portion  420  that is surrounded by the cavity  412  such as, for example, the center for the letter “O”. Other examples of letters that include island portions  420  are “Q”, “R”, “P”, “A”, “D” and “B”. Because the cavity  412  does not extend all the way through the thickness of the body  402 , the island portion  420  is supported by the remaining material on the front side  418  of the body  402 . 
     Sidewalls  422  of the cavity  412  may be undercut such that a width of the cavity  412  increases with increasing depth into the body  402  toward the front side  418 , such that the cavity  406  is widest at the bottom  414 , as shown in the example illustrated in  FIG. 4A  through  FIG. 4C . Undercutting the sidewalls  422  facilitates retention of the fill material  406  in the cavity  412  and the island portion  420  after the fill material  406  is exposed by removing the material from the front side  418  of the body  402 . 
     A cross section of the body  402  after filling the cavity  412  with the fill material  406  at  304 , and before removing material from the front side  418  of the body  402  at  306 , is illustrated in  FIG. 4B . In the illustrated example, the backside  404  of the body  402  is covered with the fill material  406 , filling the cavity  412  up to a top of the frame  410 . The fill material  406  may be filled to form a thick layer on the backside  404  of the body  402  and the excess fill material  406  is then removed by, for example, machining such that the fill material  406  is flush with the top of the frame  410 , as shown in  FIG. 4B . Alternatively, the backside  404  may be filled such that the top of the layer of fill material  406  is below the top of the frame  410 , or excess fill material  406  may be removed such that the top of the layer of fill material  406  is below the top of the frame  410 . 
     Air that is trapped in the cavity  412  during filling may enter the bore holes  416 . The bore holes  416  reduce the chance that air pockets are entrapped in the fill material  406  that is exposed on the front surface  424  of the keycap  204  when material is removed from the front side  418  the body  402 . 
     A cross section of a body  402  and fill material  406  after body and fill material is removed from the front side  418  to expose the fill material  406  on the front surface  424  of the keycap  204  at  306  is illustrated in  FIG. 4C . The fill material  406  exposed on a front surface  424  of the keycap  204  is in the shape of the character associated with the keycap  204 . 
       FIG. 4A  through  FIG. 4C  show a portion  426  of the body  402  surrounding the frame  410 . The portion  426  of the body  402  may be part of the keycap  204 . Alternatively, when multiple keycaps  204  are produced on the body  402 , the portion  426  may be part of the adjacent keycaps  204  and the frame  410  is shared between the adjacent keycaps  204 . Alternatively, a single keycap  204  may be formed from a body  402  that is larger than the keycap  204  and the portion  426  is extraneous material that is removed prior to assembling the keyboard  120 . 
     An example of a keycap  500  is illustrated in  FIG. 5A  through  FIG. 8B .  FIG. 5A  and  FIG. 5B  illustrate a backside  502  of a body  504  of the keycap  500  after material is removed from the body  504  and before filling with a fill material  506 . The body  504  of the example keycap  500  is metal. Alternatively, the body  504  may be a plastic that differs from the fill material  506 . Cavities  508 ,  510  and a frame  512  are formed on the backside  502  by removing material from the body  504 . The frame  512  extends around the periphery of the backside  502  of the body  504 . 
     The example keycap  500  shown in  FIG. 5A through 8B  is associated with the letter “Q” and the symbol “#”. The cavities  508 ,  510  are the shape of the mirror image of the letter “Q” and the symbol “#”, respectively. Both the letter “Q” and symbol “#” have island portions  514 ,  516  at their centers. The island portions  514 ,  516  are surrounded by the cavities  508 ,  510 . Because the cavities  508 ,  510  do not extend through to a front side  518  of the body  504 , the island portions  514 ,  516  are supported by the remaining material on the front side  518  of the body  504 . The cavities  508 ,  510  include a plurality of bore holes  520  that extend from bottoms  522  of the cavities  508 ,  510  through to the front side  518  of the body  504 . 
       FIG. 6  illustrates a perspective view of the backside  502  of a cutaway of the body  504  shown in  FIGS. 5A and 5B .  FIG. 6  illustrates the depth of the cavities  508 ,  510  and the bore holes  520  that extend through to the front side  518  of the body  504 .  FIG. 6  also illustrates that sidewalls  524  of the cavities  508 ,  510  are undercut such that the widths of the cavities  508 ,  510  increase as the cavities  508 ,  510  extend toward the front side  518  of the body  504 . 
       FIG. 7A  and  FIG. 7B  illustrate the backside  502  of the body  504  after the cavities  508 ,  510  and the frame  512  are filled with the fill material  506 . The fill material  506  in the example illustrated in  FIG. 7A  and  FIG. 7B  is a translucent plastic and is flush with a top of the frame  512 . 
     Air that is trapped in the cavities  508 ,  510  when body  504  is filled with the fill material  506  may enter the bore holes  520 , reducing the chance of formation of air pockets in the fill material  506  that is exposed when the material on the front side  518  of body  504  is removed. 
       FIG. 8A  and  FIG. 8B  illustrate the front surface  526  of the example keycap  500  after the material on the front side  518  of the body  504  is removed to expose the fill material  506 . The exposed fill material  506  is flush with the front surface  526  of the body  504 . The exposed fill material  506  is in the shape of the letter “Q” and the symbol “#” on the front surface  526 , to indicate the characters associated with the keycap  500 . The exposed translucent plastic fill material  506  facilitates passing light through the keycap  500 . When the keycap  500  is assembled in a backlit keyboard  120 , the fill material  506  is illuminated by the light of the light source located between the keycap  500  and the back of the housing  202 , facilitating use of the keyboard  120  in low light conditions. 
     After material is removed from the front side  518  of body  504 , the island portions  514 ,  516  of the body  504  are supported by the fill material  506 . Unlike many conventional keycaps, no bridging or connecting material of the body  504  connects the island portions  514 ,  516  to the remainder of the body  504 . 
     After material is removed from the front side  518  of body  504 , the front surface  526  of the keycap  500  may be polished to reduce any roughness of the front surface. Sides  528  of the keycap  500  may also be polished. The keycap  500  is assembled with other keycaps  204  into a keyboard  120  of a portable electronic device  100 . 
     An alternative example of a cross section of a body  902  after material has been removed from a backside  904  of the body  902  and before the body  902  is filled with a fill material is illustrated in  FIG. 9 . Material is removed from the body  902  to form a frame  906  and a cavity  908  having sidewalls  910  and a bottom  912 . The sidewalls  910  are undercut such that the cavity  908  has a maximum width at a depth intermediate a backside  904  of the body  902  and a bottom  912  of the cavity  908 . The maximum width of the cavity  908  being at an intermediate depth within the cavity  908  facilitates retention of the fill material and island portions  914  within the keycap  204 . 
     Utilizing the method described above, keycaps for a keyboard of a portable electronic device may be produced. The keycaps may be comprised of a body and a fill material. Indications of characters associated with the keycaps are provided by cut outs in the body that are filled with the fill material. The method described produces keycaps with indications of characters that do not have bridging or supporting elements that connect the island portions of characters to the rest of the body of the keycap. Bridging or supporting elements result in characters having a stencil like appearance. Removing these supporting elements after the fill material is formed around them leaves gaps in the fill material, which reduces the transmittance of light through the keycap. Bore holes in the bottom of the cavity reduce the chance of formation of air pockets in the fill material exposed on the front surface of the keycap. Air pockets in the fill material reduce the transmittance of light through the fill material and diminish the quality of the front surface of the keycap. Undercutting the sidewalls of the cavities increases the support of the fill material within the cavities, facilitating retention of the fill material and inhibiting the fill material from being pushed into the body of the keycap. Undercutting the sidewalls also increases the support of the island portions of the keycaps, inhibiting the island portions from detaching from the keycap. 
     According to one example, a method for producing a keycap includes removing material from a backside of a body of the keycap to form a cavity in a shape associated with a character, filling the cavity with a fill material, and removing material from a front side of the body to expose the fill material on a front surface of the keycap. 
     According to another example, a portable electronic device includes a keyboard having a plurality of keycaps, where at least one of the keycaps is manufactured by removing material from a backside of a body to form a cavity in a shape associated with a character, filling the cavity with a fill material, and removing material from a front side of the body to expose the fill material on a front surface of the keycap. 
     According to another example, a method for producing a keycap includes removing material from one side of a body to form a cavity in a shape of a character such that the cavity does not extend through the body to an other side of the body, filling the cavity with a fill material, and removing material from the other side of the body to expose the fill material on the other side of the body. 
     The present disclosure may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the present disclosure is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.