PATENT DOCUMENT

Publication Number: US-10901559-B2
Application Number: US-201816184809-A
Country: US
Kind Code: B2

Title: Disappearing button or slider

Abstract:
An input device is operable to detect input. The input device is a deflection based capacitive sensing input device. Deflection of a metal frame of the input device causes a change in capacitance that is used to control a function of an electrical device. The input device appears invisible because it is made of the same material as the housing it is contained in. Invisible backlit holes may make the input selectively visible or invisible to the user.

Claims:
What is claimed is: 
     
       1. A laptop computer, comprising:
 a lid housing; 
 a display positioned in the lid housing; 
 a base housing coupled to the lid housing, the base housing having a top surface, the top surface comprising a metal face; 
 a keyboard coupled to the base housing and positioned at the top surface; 
 a touch input area at the metal face of the top surface of the base housing, the touch input area having a border flush with the metal face, the border being invisible to an unaided human eye; and 
 a touch input device at the base housing to detect input within the border using a capacitive sensor, the touch input device being invisible to the unaided human eye. 
 
     
     
       2. The laptop computer of  claim 1 , wherein the touch input device is a track pad device comprising an at least two-dimensional array of capacitive sensors in the base housing, wherein the touch input area is flush with a frame in the top surface surrounding the border, and wherein the touch input area has a reconfigurable visual appearance. 
     
     
       3. The laptop computer of  claim 1 , wherein the top surface comprises a metal material having a set of perforations, wherein the capacitive sensor is configured to detect input via movement of the touch input area of the top surface. 
     
     
       4. The laptop computer of  claim 1 , wherein the touch input area has a reconfigurable visual appearance. 
     
     
       5. The laptop computer of  claim 1 , wherein at least the border of the touch input area is illuminable from within the base housing. 
     
     
       6. The laptop computer of  claim 1 , wherein the touch input device comprises an at least two-dimensional array of capacitive sensors. 
     
     
       7. The laptop computer of  claim 1 , wherein the touch input device is a track pad device. 
     
     
       8. The laptop computer of  claim 1 , wherein the top surface comprises a frame portion surrounding the border, the touch input area being integral with and flush with the frame portion. 
     
     
       9. The laptop computer of  claim 1 , wherein a marker visible at the top surface indicates a location of the touch input area. 
     
     
       10. The laptop computer of  claim 1 , wherein the touch input area is positioned on the base housing on an opposite side of the keyboard relative to a coupling between the lid housing and the base housing. 
     
     
       11. The laptop computer of  claim 1 , wherein a function of the touch input device is dependent upon an operating state of the laptop computer. 
     
     
       12. An electronic computing device, comprising:
 a housing having an outer surface; 
 a display positioned in the housing and visible through the outer surface; and 
 a touch input device positioned in the housing, the touch input device configured to detect touch input through the outer surface within a touch input border on the outer surface via a change in capacitance induced by the touch input, wherein the touch input border is flush with the outer surface, wherein an appearance of the touch input device in the housing and the touch input border are configurable to be hidden in the outer surface by being unresolvable by an unaided human eye. 
 
     
     
       13. The electronic computing device of  claim 12 , wherein the outer surface covers the touch input device. 
     
     
       14. The electronic computing device of  claim 12 , wherein the touch input device is a track pad. 
     
     
       15. The electronic computing device of  claim 12 , wherein the touch input device is positioned in the housing spaced away from the display. 
     
     
       16. The electronic computing device of  claim 12 , wherein the outer surface of the housing extends across a lid portion and a base portion of the housing, the lid portion and the base portion being joined to each other by a hinge, the display being positioned in the lid portion, the touch input device being configured to detect touch input through the base portion. 
     
     
       17. A laptop computer, comprising:
 an upper housing; 
 a display positioned in the upper housing; 
 a lower housing coupled to the upper housing by a hinge, the lower housing having a top surface; 
 a keyboard coupled to the lower housing and positioned at the top surface; 
 a track pad area in the top surface of the lower housing, the track pad area being positioned opposite the display relative to the keyboard; and 
 a contextual control in the top surface of the lower housing, the contextual control being positioned opposite the display relative to the keyboard, the contextual control being configurable between a hidden configuration and a visible configuration, wherein in the hidden configuration, a border of a touch-sensitive portion of the contextual control is invisible to an unaided human eye, wherein configuration of the contextual control between the hidden configuration and the visible configuration is dependent upon activation of an application by the laptop computer or by connection of the laptop computer to an external device. 
 
     
     
       18. The laptop computer of  claim 17 , wherein a function of the contextual control is dependent upon an operating state of the laptop computer. 
     
     
       19. The laptop computer of  claim 17 , wherein the contextual control is positioned in a corner portion of the top surface of the lower housing. 
     
     
       20. The laptop computer of  claim 17 , wherein the contextual control is configured to receive capacitive touch input. 
     
     
       21. The laptop computer of  claim 17 , wherein the contextual control is configurable between the hidden configuration and the visible configuration dependent upon an operating state of the laptop computer.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of U.S. patent application Ser. No. 15/217,273, entitled “Disappearing Button or Slider,” filed on Jul. 22, 2016, which is a continuation of U.S. patent application Ser. No. 14/282,375, entitled “Disappearing Button or Slider,” filed on May 20, 2014, now U.S. Pat. No. 9,400,579, issued on Jul. 26, 2016, which is a continuation of U.S. patent application Ser. No. 13/888,579, entitled “Disappearing Button or Slider,” filed on May 7, 2013, now U.S. Pat. No. 8,786,568, issued on Jul. 22, 2014, which is a continuation of U.S. patent application Ser. No. 12/257,956, entitled “Disappearing Button or Slider,” filed on Oct. 24, 2008, now U.S. Pat. No. 8,436,816, issued on May 7, 2013, the disclosures of which are hereby incorporated by reference herein in their entireties. 
     This is related to U.S. patent application Ser. No. 11/551,988 filed Oct. 30, 2006, titled “INVISIBLE, LIGHT-TRANSMISSIVE DISPLAY SYSTEM,” and assigned to the assignee of the present application. The Ser. No. 11/551,988 application is a continuation-in-part of U.S. patent application Ser. No. 11/456,833 filed Jul. 11, 2006 titled “INVISIBLE, LIGHT-TRANSMISSIVE DISPLAY SYSTEM,” and assigned to the assignee of the present application. The Ser. No. 11/551,988 and the Ser. No. 11,456,833 applications are both herein incorporated in their entirety by reference thereto. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates generally to input devices and device display systems, and more particularly to invisible input systems and device display systems. The input devices and display systems may become visible when illuminated from behind through invisible holes. 
     Background Art 
     In the world of consumer devices, and particularly consumer electronics, there is an ever-present demand for improved appearance, improved functionality, and improved aesthetics. Industrial design has become a highly skilled profession that focuses on fulfilling this need for enhanced consumer product appearance, functionality, and aesthetics. 
     One area that receives attention for improvement, particularly in consumer electronics, is user input and interface. Presently there exists a range of mechanically actuated (e.g., buttons, switches, levers, keys, keyboards, dials, click wheels, scroll wheels, and the like) or electrically actuated (e.g., touch pads, track pads, touch screens, multi-touch screens, and the like) input devices. These input devices interface with their associated electronic devices (e.g., computers, laptop computers, media devices, mobile phones, calculators, medical devices, etc. . . . ) in order to control a function of the device, for example, turn the device on or off, open a menu, move a cursor and so forth. 
     One challenge with these known input devices is that they may detract from the aesthetics of the device by interrupting the continuity of the device housing. To illustrate, compare a mobile phone having a traditional key pad with the iPhone produced by Apple Inc. of Cupertino, Calif. The iPhone has a flat touch-sensitive screen which presents a striking, seamless design, while the traditional mobile phone presents a cluttered array of keys and buttons. Besides the obvious aesthetic advantages of having a seamless design, a seamless design may have improved functionality and/or durability. For example, a traditional mechanical key pad can wear out over time and/or be ruined by dirt or moisture entering into the openings in the device housing. These openings are necessary to accommodate the traditional keys and buttons. 
     The iPhone touch screen uses capacitive sensing. This type of sensing takes advantage of the fact that two electrical fields separated by a dielectric produce capacitance. In the iPhone, a first electrical field is produced inside the iPhone by an array of electrodes. The second electrical field is provided by the user&#39;s finger. When the finger interacts with the glass touch surface a circuit inside the iPhone detects a change in capacitance and processes this change in order to compute, for example, the location and speed of the scrolling finger. Some modem track pads on laptop computers may function in a similar way, but normally have plastic or rubber track surfaces. In all of these devices the housing of the device is normally metal, while the track surface is normally a dielectric material such as rubber, plastic, or glass. Therefore, a truly seamless design has been impossible. Furthermore, a glass surface may be fragile. 
     Taken to its extreme, seamless design would have an invisible input. Since a metal housing is advantageous for aesthetic, environmental, and manufacturing reasons, this presents a particular challenge. One method to overcome this challenge is to include a plastic input painted to look like metal. However, this will not match the metal look and finish exactly, so the truly seamless design is not realized. 
     Another area that continually receives great attention for improvement is user displays. Providing crisp, attractive, unambiguous, and intuitively friendly displays and information for the user is very important in many consumer products. However, as consumer products constantly become smaller and smaller, and in some cases more and more complex, it becomes increasingly difficult to present and display user information in a manner that is easy for the user to grasp and understand, but is also in an uncluttered form and appearance that is aesthetically pleasing. 
     Much of the aesthetic appeal of a consumer product can quickly be compromised if there are too many display elements, or if too much display area is occupied by display elements that are not needed except at particular times. When not needed, these “passive” or unactivated display elements invariably remain visible to the user, even though they are in the “off” state. This is not only displeasing from an aesthetic standpoint, but it can be an annoying distraction that interferes with detection and understanding of other display elements that need to be observed at a given moment. 
     Illuminating display elements is known. Some display elements are illuminated continuously; others are illuminated only when appropriate to instruct and guide the user. Display elements that are not continuously illuminated can still be distracting, or at least aesthetically objectionable, when not illuminated (when in the off state) because they may still remain visible in the display area. 
     For example, one typical such display element is configured from transparent plastic inserts that penetrate through the metallic case of an electronic device, and are smoothly flush with the outer surface of the case. A large number of such always-visible display elements leads to a cluttered, confusing, and unattractive appearance. In fact, even a single such element, when not illuminated (i.e., in an inactive state), can become an unattractive distraction on an otherwise smooth and attractive surface. 
     Less expensive device housings, for example, those made of opaque plastic rather than metal, are often similarly provided with transparent plastic inserts for illuminated display elements. These display elements also conflict with a good aesthetic appearance when they are not illuminated. Also, displays using plastic or glass are less durable than metal and are more subject to breaking or cracking. 
     Additionally, the separate visible inserts utilized by prior techniques sometimes do not fit perfectly in the holes in which they are inserted or formed. Such imperfect fit can invite entry of liquids, dirt, and the like, undesirably causing yet another disadvantage. 
     Thus, the need exists for commercially feasible device display systems with improved aesthetics that unobtrusively furnish information as appropriate, but otherwise do not distract or detract from the user&#39;s experience or the device&#39;s performance. Preferably, selected elements of such display systems would additionally become invisible in their off states. 
     In view of ever-increasing commercial competitive pressures, increasing consumer expectations, and diminishing opportunities for meaningful product differentiation in the marketplace, it is increasingly critical that answers be found to these challenges. Moreover, the ever-increasing need to save costs, improve efficiencies, improve performance, and meet such competitive pressures adds even greater urgency to the critical necessity that answers be found. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention relates in one embodiment an electronic device having an invisible input. The device has a frame having a top face with invisible holes formed therein. A capacitor reference is on an inner surface of the top face in the area of the invisible holes. An interior wall is separated from the top face and forms an interior space having a dielectric medium disposed therein. A capacitor plate is disposed on a surface of the interior wall opposite the first capacitor plate. A light source is disposed in the interior space and is configured to shine through the invisible holes. A capacitor sensor is electrically connected to the capacitive reference and the capacitor plate. When an object is placed on the frame in the area of the invisible holes and pressure is applied, the frame deforms. This deformation causes a change in capacitance between the capacitive reference and the capacitor plate. The capacitor sensor detects this change and converts it to an electrical signal. 
     The invention relates in another embodiment to an invisible input. The invisible input has a frame having a top face with invisible holes formed therein. A capacitor reference is on an inner surface of the top face in the area of the invisible holes. An interior wall is separated from the top face and forms an interior space having a dielectric medium disposed therein. A capacitor plate is disposed on a surface of the interior wall opposite the first capacitor plate. A light source is disposed in the interior space and is configured to shine through the invisible holes. A capacitor sensor is electrically connected to the capacitive reference and the capacitor plate. When an object is placed on the frame in the area of the invisible holes and pressure is applied, the frame deforms. This deformation causes a change in capacitance between the capacitive reference and the capacitor plate. The capacitor sensor detects this change and converts it to an electrical signal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES 
       Certain embodiments of the invention have other aspects in addition to or in place of those mentioned above. The aspects will become apparent to those skilled in the art from a reading of the following detailed description when taken with reference to the accompanying drawings. The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which: 
         FIG. 1  is a perspective view of an electronic device according to the present invention; 
         FIG. 2  is a cross sectional view of the electronic device of  FIG. 1 , taken along line  2 - 2  in  FIG. 1  in a first position; 
         FIG. 3  is another cross sectional view of the electronic device of  FIG. 1 , taken along line  2 - 2  in  FIG. 1  in a second position; 
         FIG. 4 . is a cross sectional view of an alternate embodiment of the electronic device of  FIG. 1 ; 
         FIG. 5A  is a perspective view of an embodiment of the electronic device of  FIG. 4 ; 
         FIG. 5B  is a magnified view of a portion of the electronic device of  FIG. 5A ; 
         FIG. 6  is a perspective view of another electronic device according to the present invention; 
         FIG. 7  is a cross sectional view of the electronic device of  FIG. 6 , taken along line  7 - 7  in  FIG. 6  in a first position; 
         FIG. 8  is another cross sectional view of the electronic device of  FIG. 6 , taken along line  7 - 7  in  FIG. 6  in a second position; 
         FIG. 9  is another cross sectional view of the electronic device of  FIG. 6 , taken along line  7 - 7  in  FIG. 6  in a third position; 
         FIG. 10 . is a cross sectional view of an alternate embodiment of the electronic device of  FIG. 6 ; 
         FIG. 11  is a perspective view of an alternate embodiment of the electronic device of  FIG. 6 ; 
         FIG. 12  is a schematic of a conventional track pad; 
         FIG. 13  is a perspective view of an electronic device according to the present invention; 
         FIG. 14  is a schematic plan view of internal portions of the electronic device of  FIG. 13 ; 
         FIG. 15  is a cross sectional view of the electronic device of  FIG. 13 , taken along line  15 - 15  in  FIG. 13 ; 
         FIG. 16  is a schematic plan view of internal portions of the electronic device of  FIG. 13 ; 
         FIG. 17  is a perspective view of an alternate embodiment of the electronic device of  FIG. 13 ; 
         FIG. 18  is a cross sectional view of another electronic device according to the present invention; 
         FIG. 19  is a cross sectional view of another electronic device according to the present invention; 
         FIG. 20  is a cross sectional view of another electronic device according to the present invention; 
         FIG. 21  is a cross sectional view of another electronic device according to the present invention; 
         FIG. 22  is a cross sectional view of another electronic device according to the present invention; 
         FIG. 23  is a cross sectional view of another electronic device according to the present invention; 
         FIG. 24  is perspective view of a laptop computer according to the present invention; 
         FIG. 25  is a front view of a laptop computer according to the present invention; and 
         FIG. 26  is a front view of a laptop computer according to the present invention. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     The present invention will now be described in detail with reference to a few preferred embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order not to unnecessarily obscure the present invention. 
     Likewise, the drawings showing embodiments of the system are semi-diagrammatic and not to scale and, particularly, some of the dimensions are for the clarity of presentation and are shown greatly exaggerated in the drawing figures. 
     Similarly, although the views in the drawings for ease of description generally show similar orientations, this depiction in the figures. is arbitrary for the most part. Generally, the invention can be operated in any orientation. In addition, where multiple embodiments are disclosed and described having some features in common, for clarity and ease of illustration, description, and comprehension thereof, similar and like features one to another will ordinarily be described with like reference numerals. 
     Referring now to  FIG. 1 , a generic electronic device  10  is shown. Device  10  could be, for example, a laptop computer, a media device, a remote control, a game player, or any other device that requires a button or switch. Device  10  features an invisible button or switch  20 , whose location is shown in phantom. Button  20  is used to control some function associated with electronic device  10 . Device  10  has a metal frame  30 , which may be, for example, aluminum. Button  20  is invisible because it is made from and integral with the same metal as frame  30 . Button  20  is flush with and does not bulge out or otherwise protrude into or out of frame  30 . Therefore, it is not visible from the exterior of device  10 . Frame  30  may have markings (e.g., paint, texture) to indicate the location of button  20 . 
       FIG. 2  shows a side cross sectional view of device  10 , taken along line  2 - 2  shown in  FIG. 1 . Metal frame  30  has a face  40 . Inside of device  10 , there is an interior wall  50  below face  40 . In between face  40  and wall  50  is a dielectric medium  60 , such as air. In another implementation, dielectric medium  60  can be foam or rubber. In these implementations, supports  70  could be unnecessary and therefore removed. Supports  70  are disposed between face  40  and interior wall  50 . Dielectric medium  60  can be a dielectric gel (instead of air). 
     In the vicinity of invisible button  20 , a capacitor plate  80  is disposed on an inner surface of face  40 , and another capacitor plate  85  is disposed on a top surface of interior wall  50  opposite plate  80 . Capacitor plates  80  and  85  may be attached to, for example, printed circuit boards (PCBs) which are disposed on face  40  and/or wall  50 . In one embodiment, wall  50  is a PCB. In another embodiment, capacitor plates  80  and/or  85  can comprise conductive paint printed on face  40  and wall  50 . As used herein, a “capacitor plate” could be any conducting material which is separated from another conducting material. In the illustrated embodiment, capacitor plates  80  and  85  are shown as discrete objects attached to face  40  and wall  50 . In another embodiment (not shown) the face  40  and wall  50  themselves may function as capacitor plates. 
     There is a fixed separation between capacitor plates  80  and  85  when button  20  is not being depressed. This is important because the capacitance, C, between separated plates  80  and  85  is a function of their separation. When button  20  is not depressed, the zero-pressure capacitance, C 0 , is related to the initial separation of plates  80  and  85 . Departures from the initial separation will cause a change in capacitance, ΔC≡C−C 0 , which can be detected and processed by device  10 . In practice, C 0  may not be strictly a function of separation. Other factors, such as changes in temperature, humidity, age of components, and the like can cause minor fluctuations in C 0 . Therefore, a new estimate or baseline for the zero-pressure C 0  may be updated. In one embodiment, this update can be done each time device  10  starts up. In another embodiment, this update can be done during certain time intervals (for example every few minutes). Updating C 0  helps to ensure higher sensitivity and lower occurrences of false triggers. 
     When a user presses down on invisible button  20 , face  40  deflects between supports  70 , as shown in  FIG. 3 . This causes the distance between capacitor plates  80  and  85  to decrease, creating an associated change in capacitance, ΔC. A capacitive sensor (not shown) associated with device  10  detects this change, and if the change is above some preset threshold, T, a button function is activated. In other words if ΔC≥T the button function is activated. For example, when the user presses down on button  20 , device  10  may turn on or off. Since both capacitor plates  80  and  85  are internal to device  10 , it is not necessary to push button  20  with a conducting material, e.g., a finger or stylus, as is the case with traditional capacitive sensing technology (e.g., glass touch screens). In contrast to traditional capacitive sensing surfaces, a user could successfully activate button  20  wearing a non-conductive glove, for example. 
     The on/off, or “binary,” mode of operation described above is the simplest mode. In other embodiments, the change in capacitance ΔC could be correlated to a “continuous” output functionality. In this implementation, a larger ΔC could be associated with a command to full intensity. A very small ΔC could be associated with a command to low intensity. For example, how far the user presses down could correlate to how bright to make a light, for example, how loud to play music, or how fast to go forward or backward in a movie. In this continuous functionality mode, the correlation between capacitor plate distance and change in capacitance ΔC must be found through routine experiment, theory, calculation or combinations thereof. In other embodiments, button  20  could have three levels of functionality. This is a compromise between the binary and continuous modes. For example, before the user presses down, device  10  is “off” when the user presses down a certain amount, device  10  operates at 50%, and when the user presses down a certain amount more, device  10  operates at 100%. This could mean that device  10  could be used to turn a light from off, to 50% intensity, to 100% intensity depending on user input. Of course, many variations of this multi-level functionality mode are possible (e.g., 4 or more levels). 
     Supports  70  limit the area where a user can activate button  20 . In the illustrated embodiment, if a user presses down to the left of the left support  70 , for example, capacitor plates  80  and  85  will not appreciably move towards each other. Therefore, a change in capacitance (if any) will not exceed the threshold required to register a button depression, i.e., ΔC&lt;T. The supports can be closely spaced, thereby making the effective area of button  20  small, or the supports can be widely spaced, thereby making the effective area of button  20  large, as is shown in the illustrated embodiment. The configuration of supports  70  is shown for illustration only and may be widely varied. For example, there could be two supports, as shown in the illustrated embodiment, or there could be more than two supports, or only one support. In one embodiment (not shown), the entire surface  40  can function as button  20  if supports  70  are removed. In this implementation, the outer vertical part of frame  30  functions to keep face  40  and wall  50  separated when button  20  is not being depressed. Therefore, supports  70  are not necessary. 
     Supports  70  may be etched out of face  40  and/or wall  50  or they may be free standing. In one embodiment, Supports  70  are formed by etching the bottom surface of face  40  so that supports  70  extend downwardly. In another embodiment, supports  70  are formed by etching the top surface of interior wall  50  so that supports  70  extend upwardly. In another embodiment, face  40  and wall  50  and supports  70  are formed by etching out parts of a monolithic piece. In another embodiment, free standing supports  70  are affixed to face  40  and wall  50  by techniques known in the art, for example adhesives, welds, fasteners, etc. 
     In some embodiments, it may not be desirable to have button  20  visible or invisible all of the time. As previously mentioned, although frame  30  may have markings (e.g., paint, texture) to indicate the location of button  20 , these markings would be visible all of the time and detract from the aesthetic simplicity of housing  30 . To selectively control the visibility of button  20 , tiny invisible micro-perforations or holes  90  can be formed in face  40  as shown in  FIG. 4 . Button  20  can be selectively backlit to highlight its location by, for example, shining light through holes  90 . In one embodiment, a light source, for example a light emitting diode (LED)  95  can be placed on wall  50  under the location of button  20 . As shown in  FIG. 5A , the location of button  20  is visible LED  95  is activated. 
     In one embodiment, the backlight (e.g., LED  95 ) can be activated whenever electronic device  10  is “on.” In another embodiment, the backlight can be activated as a function of an operating state of device  10 , for example, when a CD-ROM is inserted, when a memory stick is inserted, and so on, depending on the nature of electronic device  10 . In another embodiment, the backlight can be activated as a function of ambient lighting conditions, for example, in low light (dark) conditions. In this embodiment, a light sensor (not shown) may interface with LED  95 . In another embodiment, the backlight can be activated continuously. In another embodiment, the backlight can be activated when a user taps or presses down on button  20 . In another embodiment, a motion sensor (not shown) may interface with LED  95  and activate it when motion is detected. In another embodiments heat and/or sound sensors (not shown) can interface with and activate LED  95  when heat and/or sound is detected. 
       FIG. 5B  is a magnified view of button  20  shown in  FIG. 5A . A pattern  22  of holes  90  can be disposed on frame  30  to indicate the borders of button  20 . This pattern can be formed by, for example, laser cutting through frame  30 . The holes  90 , although shown greatly exaggerated in the Figure, are actually invisible. That is, each of the holes  90  is smaller than resolvable by an unaided human eye. For example, the limit of resolution for the human eye is about 0.1 mm at a distance from the eye of 1 meter. In children, the resolution might be somewhat finer, for example, 0.04 mm. Thus, depending upon the anticipated viewer and viewing distance, the holes  90  will be selected to be below the limit of resolution, and it will accordingly be understood that the term “invisible hole” refers to this upper limit. Thus, as defined herein, “invisible holes” refers to holes that are smaller than resolvable by an unaided human eye. In one embodiment, the diameter of invisible holes  90  can range from between 20 μm to 80 μm, inclusive. Light shining through holes  90  is visible to the naked eye. This gives the impression that button  20  can be made visible or invisible at will. 
     In another embodiment, the pattern of holes  22  can be made to resemble the function of button  20 , for example, the pattern can resemble a triangle to indicate a “play” function when controlling music selections, or the pattern can resemble a square to indicate a “stop” function. In this way, when the backlighting is activated, a play or stop symbol appears on device  10  at the location of button  20 . In another embodiment (not shown), pattern  22  can resemble text or numbers. Micro-perforated invisible holes  90  are explained in greater detail in U.S. patent application Ser. No. 11/551,988 filed Oct. 30, 2006, titled “INVISIBLE, LIGHT-TRANSMISSIVE DISPLAY SYSTEM,” and U.S. patent application Ser. No. 11/456,833 filed Jul. 11, 2006 titled “INVISIBLE, LIGHT-TRANSMISSIVE DISPLAY SYSTEM.” The Ser. No. 11/551,988 and the Ser. No. 11,456,833 applications are both herein incorporated in their entirety by reference thereto. 
     As discussed above, button  20  is particularly suited to applications involving binary or on/off operations. Button  20  is also suited to applications involving continuous output functions; but, as discussed, a possibly complicated correlation between button displacement and change in capacitance is necessary for button  20  to be able to control a continuous output function. A simpler way to control a continuous output function involves using multiple pairs of capacitive plates, as will be discussed below. 
     Referring now to  FIG. 6 , a generic electronic device  100  is shown. Device  100  features an invisible “slider” or switch  110 , whose location is shown in phantom. Slider  110  is used to control some function associated with electronic device  100 . Device  100  has a metal frame  120 . Slider  110  is invisible because it is integral with and made from the same metal as frame  120 . Furthermore, slider  110  is flush with and does not bulge out or otherwise protrude into or out of frame  120 , therefore it is not visible from the exterior of device  100 . Slider  110  has a first end  190  and a second end  195 . 
       FIG. 7  shows a side cross sectional view of device  100 , taken along line  7 - 7  shown in  FIG. 6 . Metal frame  120  has a face  130 . Inside of device  100 , there is an interior wall  140  below face  130 . In between surfaces  130  and  140  is a dielectric medium  150 , e.g., air. Supports  160  are disposed between outer surface  130  and interior surface  140 . Face  130  may have markings (e.g., paint, texture) to indicate the location of slider  110 . 
     A first pair of capacitor plates  170  and  175  and a second pair of capacitor plates  180  and  185  are situated along the left and right sides, respectively, of invisible slider  110 . Upper plate  170  is disposed on an inner surface of face  130 , and capacitor plate  175  is disposed on a top surface of interior wall  140 . Capacitor plates  170  and  175  may be attached to, for example, PCBs which are attached to face  130  and/or wall  140 . In one embodiment, wall  140  is a PCB. In another embodiment, capacitor plates  170  and/or  175  can comprise conductive paint printed on face  130  and wall  140 . The second pair of capacitor plates  180  and  185  are disposed similar to the first pair  170  and  175 . In the illustrated embodiment, capacitor plates  170 / 175  and  180 / 185  are shown as discrete objects attached to face  130  and wall  140 . In another embodiment (not shown) the face  130  and wall  140  themselves may have conductive areas and non-conductive areas so as to form a pair of opposing capacitor plates. When two or more sensors are used, for example, two or more pairs of capacitor plates, the slider function is enabled. 
     There is a fixed separation between the opposite capacitor plates of each pair ( 170 / 175  and  180 / 185 ) when slider  110  is not being depressed. This is important because the capacitance, C, between plates  170 / 175  and  180 / 185  is a function of their separation. Departures from the initial separation will cause a change in capacitance, ΔC, which can be detected and processed by device  100 . In this embodiment the first pair of capacitive plates  170 / 175  is characterized by C 1  and ΔC 1 , while the second pair of capacitive plates  180 / 185  is characterized by C 2  and ΔC 2 . As discussed above, the zero-pressure capacitances between plates  170 / 175  and plates  180 / 185  may be updated to account for changes due to other factors such as temperature, humidity, age of components, etc. 
     Referring back to  FIGS. 1-3 , if a user presses down on binary invisible button  20  far enough to meet a threshold change in capacitance, a button signal is detected. In other words, the exact location of the user&#39;s finger is not critical to the operation of button  20  as long as it is over button  20 . Now referring back to  FIG. 7 , with slider  110 , the location of the user&#39;s finger (or other object) is critical. Slider  110  can be correlated with a continuous output scale from 0% to 100% so that when the user presses down on slider  110  10% of the way between its extreme ends  190  and  195 , a function will be commanded at 10% intensity. In one application, slider  110  could be a volume control wherein a user simply and intuitively presses at (or slides to) the desired volume level. In one application, end  190  is correlated to the 100% intensity level, while end  195  is correlated to the 0% intensity level. This concept is explained in greater detail below. 
     When a user presses down on invisible slider  110 , the metal outer face  130  deflects between supports  160 , as shown in  FIG. 8 . This causes the distance between capacitor plates  170  and  175  to decrease, with an associated change in capacitance ΔC 1  between them. A capacitive sensor (not shown) associated with device  100  detects this change. In the illustrated embodiment, the user has pressed down on slider  110  near end  190  (i.e., the high intensity end). Note that the separation between the first pair of capacitor plates  170 / 175  has markedly decreased, while the separation between the second pair of capacitor plates  180 / 185  has barely changed. The capacitive sensor (not shown) therefore detects a smaller change in capacitance ΔC 2  associated with the second pair. The capacitive sensor converts these respective changes in capacitance to electrical signals S 1  and S 2 . 
     At this point, electronics (not shown) associated with device  100  can compare the signal S 1  generated by the first pair of capacitor plates  170 / 175  with the signal S 2  generated by the second pair of capacitor plates  180 / 185  in order adjust a continuous output function in accordance with the exact position along slider  110  of the user&#39;s finger. One way to do this is by taking a ratio of the two signals. In the illustrated embodiment, the separation between the first pair of capacitor plates  170 / 175  is very small and so S 1  will be a large signal. The second pair of capacitive plates  180 / 185  are relatively unperturbed from their initial (neutral) positions. Therefore, the signal they generate, S 2 , will be very small. Consequently, the ratio S 1 :S 2  will be enormous. A large signal ratio can be correlated to having the user&#39;s finger near end  190 . When the user is pressing down near end  190 , he intends to command a high intensity, perhaps near 100%. Therefore, device  100  will operate near 100% intensity. This could mean that music is played loudly, a light comes on brightly, or any other continuous output function is commanded to near 100% intensity. 
     In another implementation, slider  110  can be used to control a scrolling function, for example to scroll down (or left/right) a page of text or to scroll through music selections. When the user presses slider  110  near end  190 , the scroll will go, for example, forward at maximum speed. When the user presses slider  110  near end  195 , the scroll will go in reverse at maximum speed. Intermediate positions on slider  110  will command a scroll at a lesser speed in the commanded direction (i.e., forward or reverse). These functions are given by way of example, slider  110  can be used to control any continuous output function associated with device  100 . 
     If the user presses down near the midpoint of slider  110  (i.e., half way between ends  190  and  195 ), as is shown in  FIG. 9 , he intends to command device  100  to operate at 50% intensity. Because the first pair of capacitor plates  170 / 175  and the second pair of capacitor plates  180 / 185  are moved closer to each other by approximately equal amounts, they will generate approximately equal changes in capacitance compared with their neutral positions, i.e. ΔC 1 ≈ΔC 2 . This means that the ratio S 1 :S 2  will be approximately 1:1. A signal ratio of 1:1 is correlated with a commanded 50% intensity level. 
     The 100% and 50% intensity situations are shown in  FIGS. 8 and 9 . A user can press slider  110  anywhere between ends  190  and  195  in order to command any intensity from 100% to 0%. Furthermore, the ratio S 1 :S 2  can be continuously computed such that the user can continuously slide his finger along slider  110  to continuously change the commanded intensity level to any desired level, provided sufficient pressure is applied to deflect upper surface  130 . 
     Supports  160  limit the area where a user can activate slider  110 . In the illustrated embodiment, if a user presses down to the left of the left support  160 , for example, neither pair of capacitor plates  170 / 175  or  180 / 185  will appreciably move towards each other. Therefore, a change in capacitance (if any) will not exceed the threshold required to register a slider depression. The supports can be closely spaced, thereby making the effective area of slider  110  small, or the supports can be widely spaced, thereby making the effective area of slider  110  large, as is shown in the illustrated embodiment. The configuration of supports  160  is shown for illustration only and may be widely varied. For example, there could be two supports, as shown in the illustrated embodiment, or there could be more than two supports, or only one support. In one embodiment (not shown), the entire face  130  can function as slider  110  if supports  160  are removed. In this implementation, the outer vertical part of frame  120  functions to keep face  130  and wall  140  separated when slider  110  is not being depressed. Therefore, supports  160  are not necessary. 
     Supports  160  may be etched out of surfaces  130  and/or  140  or they may be free standing. In one embodiment, supports  160  are formed by etching the bottom surface of face  130  so that supports  160  extend downwardly. In another embodiment, supports  160  are formed by etching the top surface of interior wall  140  so that supports  160  extend upwardly. In another embodiment, face  130  and wall  140  and supports  160  are formed by etching out parts of a monolithic piece. In another embodiment, free standing supports  160  are affixed to face  130  and wall  140  by techniques known in the art, for example adhesives, welds, fasteners, etc. 
     In some embodiments, it may not be desirable to have slider  110  visible or invisible all the time. As previously mentioned, although face  130  may have markings (e.g., paint, texture) to indicate the location of slider  110 , these markings would be visible all of the time and detract from the aesthetic simplicity of face  130 . To selectively control the visibility of slider  110 , tiny micro-perforations or holes  280  can be formed in face  130  as shown in  FIG. 10 . Slider  110  can be selectively backlit to highlight its location by, for example, shining light through holes  280 . In one embodiment, a light source, for example a light emitting diode (LED)  290  can be placed on surface  140  under the location of slider  110 . As shown in  FIG. 11 , the location of slider  110  is visible when LED  290  is activated. 
     Invisible slider  110  is depicted as being linear in  FIGS. 6-11  for ease of explanation only; however, this is not a limitation. Other shapes are also possible. For example, in one embodiment an invisible slider can be formed in the shape of a scroll wheel (not shown). Invisible slider  110  is depicted as having two pairs of capacitor plates in the figures. This is the minimum requirement for the slider functionality, because as described above, the signals from at least two separate capacitive sources can be compared to determine the location of an object placed on the slider. However, more capacitor plates can be used to give the slider more positional resolution. If for example, three pairs of capacitor plates are used, the signals from each of them can be used to determine the position of an object placed on the slider, and so on. 
     In one embodiment, the backlight (e.g., LED  290 ) can be activated whenever electronic device  100  is “on.” In another embodiment, the backlight can be activated as a function of an operating state of device  100 , for example, when a CD-ROM is inserted, when a memory stick is inserted, and so on, depending on the nature of electronic device  100 . In another embodiment, the backlight can be activated as a function of ambient lighting conditions, for example, in low light (dark) conditions. In this embodiment, a light sensor (not shown) may interface with LED  290 . In another embodiment, the backlight can be activated continuously. In another embodiment, the backlight can be activated when a user taps or presses down on slider  110 . In another embodiment, a motion sensor (not shown) may interface with LED  290  and activate it when motion is detected. In another embodiment heat and/or sound sensors (not shown) can interface with and activate LED  290  when heat and/or sound is detected. 
     A pattern (similar to pattern  22  shown in  FIG. 5B ) of holes  280  can be disposed on face  130  to indicate the borders of slider  110 . This pattern can be formed by, for example, laser cutting through face  130 . Holes  280  are formed such that they are too small for the unaided human eye to detect; therefore, they appear to be invisible. However, light shining through holes  280  is visible to the naked eye. This gives the impression that slider  110  can be made visible or invisible at will. 
     Conventional touch sensitive track pads require a dielectric outer track surface; consequently they, unlike the housing of most electronic devices, are not made from metal resulting in a clearly visible transition between housing and track pad. Referring to  FIG. 12 , a conventional touch-sensitive track pad  200  is shown. A track pad is generally a small (often rectangular) area that includes a protective/cosmetic shield  210  and a plurality of electrodes  220  disposed underneath protective shield  210 . Electrodes  220  may be located on a circuit board, for example a printed circuit board (PCB). For ease of discussion, a portion of protective shield  210  has been removed to show electrodes  220 . Each of the electrodes  220  represents a different x, y position. In one configuration, an object, such as a finger  230  (or alternately a stylus, not shown) approaches the electrode grid  220 , a tiny capacitance forms between finger  230  and the electrodes  220  proximate the finger  230 . The circuit board/sensing electronics (not shown) measures capacitance and produces an x, y input signal  240  corresponding to the active electrodes  220  which is sent to a host device  250  (e.g., a computing device) having a display screen  260 . The x, y input signal  240  is used to control the movement of a cursor  270  on display screen  260 . As shown, the input pointer moves in a similar x, y direction as the detected x, y finger motion. Besides moving a cursor, input signal  240  can be used for a variety of functions, for example, making a selection, providing instructions, etc. 
     Referring now to  FIG. 13 , a generic electronic device  300  is shown which applies the present invention to a track pad. Device  300  features an invisible track pad  310 , whose location is shown in phantom. Track pad  310  is used to control some function associated with electronic device  300 . Device  300  has a metal frame  320 . Track pad  310  is invisible because it is integral with and made from the same metal as frame  320 . Furthermore, track pad  310  is flush with and does not bulge out or otherwise protrude into or out of frame  320 . Therefore, it is not visible from the exterior of device  300 . Frame  320  may have markings (e.g., paint, texture) to indicate the location of track pad  310 . 
     Track pad  310  is similar to slider  110 , but track pad  310  has a two-dimensional matrix of capacitor plate pairs, while slider  110  has a one-dimensional line of capacitor plate pairs (see  FIG. 7 ). This two-dimensional matrix  330  of capacitor plate pairs is seen from above in  FIG. 14 . For clarity of explanation, track pad  310  is shown as having a three by three matrix of capacitor plates; however, the matrix could be as small as two by two or could have many more pairs of capacitor plates. Also for clarity of explanation, only capacitor plate pairs  340 ,  350 , and  360  are labeled. Supports  370  separate the pairs of capacitor plates, in a similar manner as supports  70  ( FIG. 3 ) and supports  160  ( FIG. 8 ) do with invisible button  20  and invisible slider  110 . 
       FIG. 15  is a cross section of device  300  taken along line  15 - 15  of  FIG. 13 . Metal frame  320  has a face  380 . Inside of device  300 , there is an interior wall  390  below face  380 . In between face  380  and wall  390  there is a dielectric medium  400 , e.g., air. Each of the capacitor plate pairs  340 ,  350 , and  360  are made up of opposing capacitor plates, similar to other embodiments of the present invention. Upper capacitor plates of each pair are disposed on an inner surface of face  380 , and lower capacitor plates of each pair are disposed on a surface of interior wall  390 . These capacitor plates may be attached to, for example, PCBs which are attached to face  380  and/or wall  390 . In one embodiment, wall  390  is a PCB. In another embodiment, capacitor plates pairs  340 ,  350 , and  360  can comprise conductive paint printed on face  380  and wall  390 . As shown in  FIG. 15 , the capacitor plates of pairs  340 ,  350 , and  360  are shown as discrete objects attached to face  380  and wall  390 . In another embodiment (not shown) the face  380  and wall  390  themselves may have conductive areas and non-conductive areas so as to form an array of pairs of opposing capacitor plates. 
     There is a fixed separation between the opposite capacitor plates of each pair when track pad  310  is not being depressed. This is important because the capacitance, C, between two plates is a function of their separation. Departures from the initial separation will cause a change in capacitance, ΔC, which can be detected and processed by device  300 . In this embodiment the first pair of capacitive plates  340  are characterized by C 1  and ΔC 1 , the second pair of capacitive plates  350  are characterized by C 2  and ΔC 2 , and the third pair of capacitive plates  360  are characterized by C 3  and ΔC 3 . In the case of a three by three matrix  330  there will be nine capacitances C 1 , C 2 , C 3 , C 4 , C 5 , C 6 , C 7 , C 8 , C 9  involved as shown in  FIG. 16 . As discussed above, the zero-pressure capacitances between pairs of capacitive plates in track pad  310  (e.g., pairs  340 ,  350 , and  360 ) may be updated to account for changes due to other factors such as temperature, humidity, age of components, etc. 
     Invisible track pad  310  operates in much the same way that invisible slider  110  does, except now a matrix of nine capacitances (for a three by three matrix shown in  FIGS. 14-16 ) and nine changes in capacitance is generated and processed when a user presses down on the surface of track pad  310 . If a user presses down right on top of capacitor plate pair  350 , a larger change in capacitance ΔC 2  will result. Changes in the other eight capacitances (see  FIG. 16 ), will be relatively smaller; this allows device  300  to infer the location of the user&#39;s finger on track pad  310  as being generally in the middle of the pad. As another example, if the user presses down on the bottom right hand corner of track pad  310 , ΔC 7  will be large, ΔC 1 , ΔC 2 , and ΔC 8  associated with the nearest neighbor capacitor plate pairs may be moderate, while the other five changes in capacitances will be relatively low (or zero). This allows device  300  to infer that the finger is generally on the bottom right side of track pad  310 . And so on. In this way, track pad  310  can command a tracking function. Using even more pairs of capacitor plates, for example a ten by twelve matrix, gives device  300  greater positional resolution but the overall concept remains the same. 
     As with conventional track pads, invisible track pad  310  can also compute the speed of an object scrolling over its surface, and it can also employ multi-touch technology. Multi-touch consists of a touch surface (track pad, screen, table, wall, etc.), as well as software that recognizes multiple simultaneous touch points, as opposed to the standard touchscreen (e.g., computer touchpad, ATM), which recognizes only one touch point. 
     In some embodiments, it may not be desirable to have track pad  310  visible or invisible all the time. As previously mentioned, although frame  320  may have markings (e.g., paint, texture) to indicate the location of track pad  310 , these markings would be visible all of the time and detract from the aesthetic simplicity of frame  320 . To selectively control the visibility of track pad  310 , tiny micro-perforations or holes (not shown) can be formed in frame  320  in the area of track pad  310 . Track pad  310  can be selectively backlit to highlight its location by, for example, shining light through the invisible holes. In one embodiment, a light source, for example a light emitting diode (LED) can be placed on surface  390  under the location of track pad  310 . As shown in  FIG. 17 , the location of track pad  310  is visible when the backlight (LED) is activated. 
     In one embodiment, the backlight (e.g., LED) can be activated whenever device  300  is “on.” In another embodiment, the backlight can be activated as a function of an operating state of device  300 , for example, when a CD-ROM is inserted, when a memory stick is inserted, and so on, depending on the nature of electronic device  300 . In another embodiment, the backlight can be activated as a function of ambient lighting conditions, for example, in low light (dark) conditions. In this embodiment, a light sensor (not shown) may interface with the backlight (LED). In another embodiment, the backlight can be activated continuously. In another embodiment, the backlight can be activated when a user taps or presses down on track pad  310 . In another embodiment, a motion sensor (not shown) may interface with the backlight and activate it when motion is detected. In another embodiments heat and/or sound sensors (not shown) can interface with and activate the backlight when heat and/or sound is detected. 
     A pattern (similar to pattern  22  shown in  FIG. 5B ) of holes can be disposed on frame  320  to indicate the borders of track pad  310 . This pattern can be formed by, for example, laser cutting through frame  320 . These holes may be formed such that they are too small for the unaided human eye to detect; therefore, they appear to be invisible. However, light shining through these holes is visible to the naked eye. This gives the impression that track pad  310  can be made visible or invisible at will. 
     The measurable changes in capacitance caused by changing the separation between two capacitor plates, for example plates  80  and  85  ( FIGS. 2-4 ), capacitor plate pairs  170 / 175  and  180 / 185  ( FIGS. 7-10 ), and capacitor plate pairs  340 ,  350 , and  360  ( FIGS. 14-16 ) is known as “mutual capacitance.” Mutual capacitance is but one general method for measuring capacitance. Another general method is to measure the capacitance between a single capacitor plate and a ground reference. This is known as “capacitance-to-ground.” This can effectively cut in half the number of capacitor plates necessary in the present invention, as long as there is a ground reference associated with the remaining capacitor plate(s). Each of these methods involve changing a separation between a capacitor plate and some other “capacitive reference.” In the mutual capacitance method, the capacitive reference is a second capacitor plate; in the capacitance-to-ground method, the capacitive reference is a ground reference. As used herein, a “capacitive reference” is either a capacitor plate or a ground reference. 
     As used herein, the term “ground” does not imply an actual connection to the Earth. Rather, a ground is commonly idealized in the electrical arts as an infinite source or sink for charge, which can absorb an unlimited amount of current without changing its potential. Of course, this is only an idealization, and as such, many surfaces can be considered a “ground” for purposes of the present invention. The term “ground” is to be broadly construed. In one embodiment, the frame of an electronic device can serve as a ground reference. In another embodiment, a ground reference can be disposed on the frame of an electronic device. 
     The capacitance-to-ground method can be used in place of the mutual capacitance methods discussed above. In one embodiment, invisible button  20  discussed with reference to  FIGS. 1-5  can use capacitance-to-ground instead of mutual capacitance. In this embodiment, either of capacitor plates  80  or  85  can be removed and replaced by a ground reference. The capacitance from the remaining capacitor plate will then be measured with respect to ground. As shown in  FIG. 18 , capacitor plate  80  can be removed and replaced with ground reference  81 , which may be a discrete member disposed on face  40  of frame  30 . In another embodiment, capacitor plate  80  can be removed and face  40  itself can be a single grounded plane forming the ground reference, as shown in  FIG. 19 . The invisible buttons of  FIGS. 18 and 19  are referred to as  20 ′ and  20 ″, respectively. These invisible button will function as previously described, but they only need a single capacitor plate (instead of the two necessary for mutual capacitance), but they also require a ground reference. As discussed, the face of the frame itself can be the ground reference, or a separate ground reference can be disposed on the frame. 
     In another embodiment, invisible slider  110  discussed with reference to  FIGS. 6-11  can use capacitance-to-ground instead of mutual capacitance. In this embodiment, either of the capacitor plates from each pair ( 170 / 175  or  180 / 185 ) can be removed and replaced by a ground reference. The capacitance from the remaining capacitor plate will then be measured with respect to ground. As shown in  FIG. 20 , capacitor plates  170  and  180  can be removed and replaced with ground references  176  and  186 , which may be discrete members disposed on face  130  of frame  120 . In another embodiment, face  130  itself can be a single grounded plane forming the ground reference, as shown in  FIG. 21 . The invisible sliders of  FIGS. 20 and 21  are referred to as  110 ′ and  110 ″, respectively. These invisible sliders win function as previously described, but they only need two capacitor plates (instead of the four necessary for mutual capacitance), but also require a ground reference(s). As discussed, the face of the frame itself can be the ground reference, or a separate ground reference(s) can be disposed on the frame. 
     In another embodiment, invisible trackpad  310  discussed with reference to  FIGS. 13-17  can use capacitance-to-ground instead of mutual capacitance. In this embodiment, either of the capacitor plates from each pair (e.g., pairs  340 ,  350 , and  360 ) can be removed and replaced by a ground reference. The capacitance from the remaining capacitor plate from each pair will then be measured with respect to ground. As shown in  FIG. 22 , the capacitor plates attached to face  380  from each of pairs  340 ,  350 , and  360  can be removed and replaced with ground references  341 ,  351 , and  361 , which may be discrete members disposed on face  380  of frame  320 . In another embodiment, face  380  itself can be a single grounded plane forming the ground reference, as shown in  FIG. 23 . The invisible track pads of  FIGS. 22 and 23  are referred to as  310 ′ and  310 ″, respectively. These invisible trackpads will function as previously described, but need only nine capacitor plates (instead of the eighteen necessary for mutual capacitance using a three by three array), but they also require a ground reference(s). As discussed, the face of the frame itself can be the ground reference, or a separate ground reference(s) can be disposed on the frame. 
     In other embodiments (not shown), the present invention can include mutual capacitance (i.e., opposing capacitor plates) and capacitance-to-ground (i.e., a capacitor plate and an opposing ground reference) in the same device. 
     The invisible input devices described above (button  20 , slider  110 , and track pad  310 ) can be used in many different implementations. Several implementations are described below. These implementations are given by way of example only, and not by way of limitation. The person of skill in the art recognizes that the present invention has wide applicability. 
     The present invention can be used, in one embodiment, as a closed-lid external button for a laptop computer. Referring now to  FIG. 24 , laptop computer  4800  is shown with its lid  4802  closed. Lid  4802  may be, for example, aluminum. Lid  4802  has an array of invisible status indicators  4804 . Status indicators  4804  could, for example, indicate the presence of and level (signal strength) of a wi-fi signal, or they could indicate battery strength. Lid  4802  has an invisible button  4806  (shown in phantom) that functions even when lid  4802  is closed. Button  4806  is based on capacitive sensing. When a user presses lid  4802  at the location of button  4806  lid  4802  deforms in that area and causes a change in capacitance, which in turn causes invisible status indicators  4804  to light up according to the level of wi-fi signal (or battery strength, etc.). Either of invisible button  4806  or invisible status indicators  4804  can employ invisible holes and backlighting to make them selectively visible or invisible to the user. 
     Referring now to  FIG. 25 , in another embodiment, laptop computer  4900  has an invisible button  4902  which may function as a closed-lid mode state change button. In one implementation, pressing button  4902  can signal a component of laptop  4900  or an associated external component to “wakeup” from a closed-lid “sleep” mode to a closed-lid “active” mode. For example, pressing button  4902  when laptop computer  4900  is in the closed-lid sleep mode, can wake up an external monitor (not shown), sync an iPod or iPhone (not shown) with laptop computer  4900 , or install software to laptop computer  4900  while lid  4904  is closed. In another implementation, in visible button  4902  can shutdown laptop computer  4900  from the closed-lid sleep or closed-lid active modes. 
     In another embodiment, the present invention can be used to replace traditional track pads and/or traditional track pad buttons with invisible buttons or invisible track pads. Referring now to  FIG. 26 , laptop computer  5000  is shown with lid  5002  open. Track pad  5004  has a track surface  5006  for scrolling and a button  5008  for clicking. In conventional track pads, track surface  5006  and button  5008  are normally separate components. Button  5008  can be replaced with an invisible button, which gives laptop  5000  a more seamless and attractive look. The track surface  5006  itself can even be replaced with an invisible track pad, such as invisible track pad  310  discussed with reference to  FIGS. 13-17 . 
     In another embodiment, invisible controls can be added to laptop computer  5000  using the present invention. In one implementation, invisible control  5009  is shown in  FIG. 26 . Invisible control  5009  may be used, for example, to control music or video stored and played from computer  5000 . Invisible control may have, for example, rewind  5010 , play  5012 , and fast forward  5014  invisible buttons and it may have increase  5016  and decrease  5018  invisible volume controls. Invisible holes may form patterns indicative of the functions of these buttons (e.g., rewind arrow, play arrow, fast forward arrow, volume increase plus, volume decrease minus, etc.). The holes may be backlit. 
     Invisible control  5009  may be a contextual control, meaning that the function of control  5009  is dependent upon an operating state of the device (in this case laptop computer  5000 ). The backlight may also be activated as a function of the operating state of the device. For example, control  5009  becomes visible automatically when a DVD is inserted into computer  5000 , when a music CD is insert into computer  5000 , or when iTunes® is active. The function of control  5009  is then adapted to either play the DVD, play the music CD, or to control iTunes® functions. iTunes® is a trade mark for a digital media player application created by Apple Inc. of Cupertino, Calif. In other implementations, invisible contextual controls (not shown) can be used to deactivate a camera, eject a disk or USB stick, or to illuminate the keyboard depending on the state of laptop  5000 . Each of these invisible contextual controls can be made to become visible under appropriate situations (e.g., when the camera is on, the disk or USB stick is in, or if it is dark, respectively). Even the entire keyboard  5020  can be replaced with an array of invisible buttons. In fact, all of the conventional keys, buttons, track pads, etc. on a laptop or other electronic device can be replaced by invisible inputs according to the present invention. In this way, the truly seamless design has become a reality. 
     While this invention has been described in terms of several preferred embodiments, there are alterations, permutations, and equivalents, which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.

Metadata:
Filing Date: 20181108
Publication Date: 20210126
Grant Date: 20210126
Priority Date: 20081024
Inventors: LEUNG, OMAR S.
AMM, DAVID T.
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03547", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y10T29/49117", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/03547", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": true, "tree": "[]"}, {"code": "F21V11/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "F21Y2115/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49117", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/169", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1652", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/169", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0202", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}, {"code": "F21V11/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "F21Y2115/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0202", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y10T29/49117", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/169", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/03547", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1652", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 42117008