PATENT DOCUMENT

Publication Number: US-10452210-B2
Application Number: US-201615356215-A
Country: US
Kind Code: B2

Title: Methods and apparatus for capacitive sensing

Abstract:
The present disclosure addresses methods and apparatus facilitating capacitive sensing using a conductive surface, and facilitating the sensing of proximity to the conductive surface. The sensed proximity will often be that of a user, but can be another source of a reference voltage potential. In some examples, the described systems are capable of sensing capacitance (including parasitic capacitance) in a circuit that includes the outer conductive surface, and where that outer conductive surface is at a floating electrical potential. In some systems, the systems can be switched between two operating modes, a first mode in which the system will sense proximity to the conductive surface, and a second mode in which the system will use a capacitance measurement to sense contact with the conductive surface.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a plurality of capacitive sensing regions arranged at different locations across the electronic device, the plurality of capacitive sensing regions including a plurality of electrodes separated by a gap from a plurality of conductive element portions held at a first potential; 
 wherein each of the plurality of capacitive sensing regions is configured to change the gap between the electrode and the conductive element portion when a first object contacts the conductive element portion; and 
 sensing circuitry coupled to the electrode in each of the plurality of capacitive sensing regions, the sensing circuitry configured to determine a change in capacitance between the electrode and the conductive element portion due to the change in the gap and detect a touch of the first object. 
 
     
     
       2. The electronic device of  claim 1 , wherein the conductive element portions are continuously formed as a surface of the electronic device. 
     
     
       3. The electronic device of  claim 1 , further comprising a processor coupled to the sensing circuitry and capable of performing one or more functions upon detection of the touch of the first object. 
     
     
       4. The electronic device of  claim 1 , further comprising a processor coupled to the sensing circuitry and capable of determining a first location of the touch of the first object. 
     
     
       5. The electronic device of  claim 4 , wherein the sensing circuitry is further configured to detect a touch of a second object, and wherein the processor is further capable of determining a second location of the touch of the second object. 
     
     
       6. The electronic device of  claim 1 , wherein the first potential is a ground potential. 
     
     
       7. The electronic device of  claim 1 , wherein the plurality of capacitive sensing regions comprise one or more touch-sensitive invisible buttons. 
     
     
       8. The electronic device of  claim 1 , wherein two or more of the plurality of electrodes are coupled together. 
     
     
       9. The electronic device of  claim 1 , wherein the gap comprises one of air or a dielectric layer. 
     
     
       10. The electronic device of  claim 1 , incorporated into a portable computing device. 
     
     
       11. The electronic device of  claim 1 , wherein the plurality of conductive element portions form a part of an external surface of the electronic device. 
     
     
       12. A method of capacitive touch sensing at an electronic device, comprising:
 forming each of a plurality of capacitive sensing regions by separating an electrode and a conductive element portion by a gap, and holding the conductive element portion at a first potential; 
 arranging the plurality of capacitive sensing regions at different locations across the electronic device; 
 changing the gap between the electrode and the conductive element portion of a particular capacitive sensing region when a first object contacts the conductive element portion of the particular capacitive sensing region; 
 determining a change in capacitance between the electrode and the conductive element portion due to the change in the gap; and 
 detecting a touch of the first object based on the determined change in capacitance. 
 
     
     
       13. The method of  claim 12 , further comprising continuously forming the conductive element portions as a surface of the electronic device. 
     
     
       14. The method of  claim 12 , further comprising performing one or more functions upon detection of the touch of the first object. 
     
     
       15. The method of  claim 12 , further comprising determining a first location of the touch of the first object. 
     
     
       16. The method of  claim 15 , further comprising detecting a touch of a second object, and determining a second location of the touch of the second object. 
     
     
       17. The method of  claim 12 , further comprising holding the conductive element portion at a ground potential. 
     
     
       18. The method of  claim 12 , further comprising forming touch-sensitive invisible buttons from the plurality of capacitive sensing regions. 
     
     
       19. The method of  claim 12 , further comprising coupling two or more of the plurality of electrodes together. 
     
     
       20. The method of  claim 12 , further comprising forming the gap from one of air or a dielectric layer. 
     
     
       21. The method of  claim 12 , wherein the conductive element portions form a part of an external surface of the electronic device. 
     
     
       22. An electronic device comprising:
 a touch-sensitive surface; 
 one or more capacitive touch sensing regions cooperatively arranged with the touch-sensitive surface, each capacitive touch sensing region including a first electrode and a second electrode separated by a gap, the second electrode being held at a first potential; 
 sensing circuitry coupled to the first electrode in each of the one or more capacitive touch sensing regions, the sensing circuitry configured for generating a first signal indicative of a capacitance between the first electrode and the second electrode; and 
 a processor cooperatively coupled to the sensing circuitry and capable of receiving the first signal and sensing a touch by detecting a change in the first signal caused by a change in a gap between the first electrode and the second electrode, the change in the gap caused by an object in contact with the touch-sensitive surface. 
 
     
     
       23. The electronic device of  claim 22 , wherein the second electrode forms an external surface of the electronic device.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation of application Ser. No. 14/275,730; filed May 12, 2014 published on Sep. 4, 2014 as U.S. Patent Publication No. US 2014/0247248; which is a continuation of U.S. patent application Ser. No. 12/861,640, filed Aug. 23, 2010 issued on Jun. 10, 2014 as U.S. Pat. No. 8,749,523; which in turn claims the benefit of U.S. Provisional Application No. 61/235,905, filed Aug. 21, 2009, and is a continuation-in-part of U.S. patent application Ser. No. 12/257,956, filed Oct. 24, 2008 issued on May 7, 2013 as U.S. Pat. No. 8,436,816, the contents of which are incorporated herein by reference in their entirety for all purposes. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to methods and apparatus for capacitive sensing; and more particularly includes methods and apparatus which use a conductive surface, such as metal, in the sensing mechanism, and which are used to detect proximity and potentially touch of a user in order to provide user input signals to an electronic device. 
     Many user interfaces are known which utilize capacitive sensing to identify user inputs to an electronic device, such as a computer, media playing device, phone etc. Some of these interfaces are implemented as touch screen systems where one or more capacitance sensing mechanisms, such as electrodes are placed under a transparent outer surface, typically formed of glass or plastic, and above a display element. 
     A limitation of many conventional capacitive sensing devices is that the outer surface needs to be formed of a non-conductive material, such as the glass outer surface of touch screen devices. Thus, even input devices that do not require transparency for operation, such as track pads that operate based upon capacitive sensing, will include a contact surface formed of glass or of another non-conductive material. 
     Thus, conventional capacitive sensing input devices for electronic devices offer some limitations on how they may be utilized. For example, applications may be envisioned where it would be desirable to allow for proximity or touch-responsive inputs even where the surface is formed of a conductor, such as a metal. Applications may be envisioned wherein some portion of the outer case of an electronic device, such as a media player or laptop computer, might be sensitive to proximity and/or touch of a user in order to initiate various functions of the device, potentially before there has been any direct contact with the device. 
     Accordingly, the methods and apparatus disclosed herein identify systems for sensing the proximity, and in some embodiments, also touch, of a user even where the surface proximate the user is formed of metal or another conductor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a simplified representation of the sensing components of a proximity sensing system in accordance with the present invention. 
         FIG. 2  depicts a schematic representation of a proximity sensing system utilizing the sensing components of  FIG. 1 . 
         FIG. 3  depicts a simplified representation of the sensing components of a proximity and touch sensing system in accordance with the present invention. 
         FIG. 4  depicts a schematic representation of proximity and touch sensing system utilizing the sensing components of  FIG. 3 . 
         FIG. 5  depicts an example flow chart of a method of operation of the proximity and touch sensing system of  FIGS. 3 and 4 . 
         FIG. 6  depicts a block diagram representation of an example electronic device which may include or be used with any of the capacitive sensing systems or methods described herein. 
         FIGS. 7A-B  depict a portion of an electronic device; wherein  FIG. 7A  depicts an invisible button region on a surface of the device; and  FIG. 7B  depicts a magnified view of a section of the invisible button region. 
         FIG. 8  depicts a portion of an electronic device with an invisible slider region on a surface of the device. 
         FIG. 9  depicts an example laptop computer is a closed lid state, the computer lid having an example invisible button, and a plurality of invisible status indicators. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following detailed description refers to the accompanying drawings that depict various details of examples selected to show how the present invention may be practiced. The discussion addresses various examples of the inventive subject matter at least partially in reference to these drawings, and describes the depicted embodiments in sufficient detail to enable those skilled in the art to practice the invention. Many other embodiments may be utilized for practicing the inventive subject matter than the illustrative examples discussed herein, and many structural and operational changes in addition to the alternatives specifically discussed herein may be made without departing from the scope of the inventive subject matter. 
     In this description, references to an “embodiment,” or to an “example” mean that the feature being referred to is, or may be, included in at least one embodiment or example of the invention. Separate references to “an embodiment” or “one embodiment” or to “one example” or “an example” in this description are not intended to necessarily refer to the same embodiment or example; however, neither are such embodiments mutually exclusive, unless so stated or as will be readily apparent to those of ordinary skill in the art having the benefit of this disclosure. Thus, the present invention can include a variety of combinations and/or integrations of the embodiments and examples described herein, as well as further embodiments and examples as defined within the scope of all claims based on this disclosure, as well as all legal equivalents of such claims. 
     For the purposes of this specification, “electronic device” as used herein, includes a system using one or more processors, microcontrollers and/or digital signal processors or other devices having the capability of running a “program,” (all such devices being referred to herein as a “processor”). A “program” is any set of executable machine code instructions, and as used herein, includes user-level applications as well as system-directed applications or daemons. Examples of electronic devices include communication and electronic devices such as cell phones, music and multi-media players, Personal Digital Assistants (PDA), and “set top boxes”; as well as computers, or “computing devices” of all forms (desktops, laptops, servers, palmtops, workstations, etc.). 
     Referring now to  FIGS. 1 and 2 ,  FIG. 1  depicts a simplified representation of the sensing components  100  of an example inventive proximity sensing system in accordance with the present invention; while  FIG. 2  depicts a schematic representation of a new proximity sensing system  200  using those sensing components. Elements of  FIG. 1  have been numbered identically in  FIG. 2 . As will be described below, proximity sensing system  200  detects proximity of an external potential source, such as a human user, to an outer conductive surface, by sensing capacitance (including parasitic capacitance) in a circuit that includes the outer conductive surface, and where that outer conductive surface is at a floating electrical potential. 
     Proximity sensing system  100  includes an enclosure, indicated generally at  102 . Enclosure  102  may be of any of a wide variety of configurations, but for purposes of the present description will be described generally in the context of an outer housing as might be used for a laptop computer. Enclosure  102  includes a metal lid  104  and a metal lower section  106 . The present invention is in no way limited to use in laptops and similar devices, but may be used with virtually any electronic device where it is desired to sense proximity of a source of electrical potential, such as a user, to a conductive outer surface. Accordingly, there is no requirement that a bottom portion of any enclosure be formed of a metal or other conductive material. In the depicted example, where sensing components include a metal enclosure  102 , it will often be desirable to insulate metal lid  104  from the metal lower section  106 . In enclosure  102 , an insulated gasket  108  is disposed between lid  104  and lower section  106 . If lid  104  is not insulated from lower section  106 , then the entire enclosure should be maintained at a floating potential. However, such configurations are believed to offer less noise immunity than systems such as that depicted, where the lower section  106  may be grounded, and thus offer shielding from outside sources of potentially interfering electrical noise. Thus, the described configuration will often offer improved measurements for determining proximity of a user. In addition to insulated gasket  108 , it will be apparent to those skilled in the art that other potential points of electrical conduction between the two components will need to be avoided. For example, this could include providing electrical insulation between the hinge components by which the lid and lower section are attached; and assuring a non-electrically conductive path through any latch assembly used to secure the two components in a closed orientation to one another. 
     In a sensing region  114  of lid  104  in which sensitivity to user proximity is desired, the metal lid will be thinned, such as by forming a recess  110  in inner surface  112  of lid  104 . The specific dimensions may vary depending upon the specific application. However, as one example, a metal thickness of approximately 0.3 to 1 mm will be appropriate for many applications, with a more preferred range being between approximately 0.4 and 0.6 mm. 
     An electrode  116  will be disposed within recess  110  proximate sensing region  114 , and in spaced relation to that region, to cooperatively form a parallel plate capacitor (C 1 ). Electrode  116  may be of any of a variety of configurations, including a solid wire or flat conductor, a plated conductor on a printed circuit board (PCB), a conductive film, such as a metal or indium tin oxide film, etc. Electrode  116  may be maintained in that spaced relation to sensing region  114  by either or both of an insulative layer, as depicted at  118 , and an air gap, as depicted at  120 . As one example, where electrode  116  is implemented in the form of a conductive film, the conductive film, along with the electrical insulator may be adhesively coupled within recess  110  to sensing region  114  of lid  104 . Electrode  116  may be implemented in any manner that in combination with lid  104  forms a capacitor that is appropriately sized in view of the electrical design of the remaining components of the system. For many applications, a minimal capacitance C 1  would be preferable, as that allows the greatest influence on measurements by the proximity-induced capacitance, as will be described in more detail below. 
     For purposes of this illustrative embodiment, electrode  116  is coupled to the input of a capacitive sensor  126 . This input provides a high impedance (at DC) connection to ground. The value of the “high” impedance will vary depending on the sensor used, but will typically be in the megohm range or higher. Lid  104 , however, is not tied to any potential, but is electrically floating. As noted previously, it is not required that lower section  106  be electrically insulated from lid  104 , and in such applications where it is not, then lower section  106  will also be at a floating potential. Capacitance sensor  126  will be coupled between reference electrode  116  and ground. Capacitance sensor  126  may be selected from commercially available alternatives. As one example, the Model ADI 7147 multi-channel sensor from Analog Devices of Norwood, Mass. is suitable for some applications. That sensor converts capacitance to voltage, and then generates a digital output representative of the measured capacitance. Where signals are provided to multiple input channels, the ADI 7147 can output measurements of each channel to facilitate various possible types of measurements or control functions. 
     As depicted in  FIG. 1 , an external potential source, which will most commonly be a user&#39;s body, such as a hand, will cooperatively form a capacitance (Cprox) with the electrically floating lid  104 . For purposes of illustration, the user may be considered as a external potential source that is, at most times, at ground potential. While not wishing to be bound by theory, in at least some implementations, electrically floating lid  104  may be considered, in effect, as an electrostatic antenna, sensitive to the potential of the user&#39;s hand. Because lid  104  is electrically floating, the total capacitance formed between the external source potential (such as the hand) and electrode  116  (C 1 +Cprox) will vary in response to proximity of the external source. 
     In operation, when an external potential source, such as a user&#39;s hand  124  comes sufficiently close to sensing region  114  of lid  104  to establish a capacitance discernible by the system, that capacitance will influence the series capacitance (C 1 +Cprox) coupled to capacitance sensor  126 . Thus, the magnitude of the capacitance may be used as a general measure of the proximity of the external potential source and that measurement can be output by capacitance sensor  126  as a digital signal. This output signal can be processed by circuitry of an associated electronic device  128  to provide a desired functionality in response to proximity of a user. 
     Those skilled in the art will recognize that there is some variability present in this measurement in many intended applications, such as where the proximity of a user&#39;s hand will be detected, as both the size and orientation of the hand may impact the capacitance measurement by capacitance sensor  126 . Many techniques for evaluating the measured capacitance to determine proximity may be contemplated. One such technique is to establish a reference of an averaged and filtered capacitance signal, which may be a moving average, and to then identify a fast change from that moving average as a measure of proximity. The strength of the proximity signal will be a function of the proximity of the conducting body and the size of the conducting body; and will typically follow a power law for larger distances, but will move generally linearly at smaller distances. 
     As will be apparent to those skilled in the art, this form of proximity determination may be used in a variety of applications. For example, proximity of a user to the exterior of an enclosure, such as the depicted enclosure for a laptop computer, might be used to wake the computer from sleep; to initiate downloading of information such as e-mails or favorite web pages. Other similar functionality may be envisioned for other devices such as media players, cell phones, etc. It should also be noted that a proximity sensor generally as described in relation to  FIGS. 1 and 2  might be used on an internal surface of the laptop. Alternatively, it might be utilized on external surface but where only a portion of the enclosure member or other outer surface component is formed of metal. 
     Due to lid  104  being at a floating electrical potential, over time it will accumulate electrical charge. As a result, it will be desirable to periodically recalibrate the sensors and to remove the capacitance accumulated on the plate. The charge may be removed by a temporary coupling of lid  104  to ground, and the floating average capacitance value may be reset to achieve such recalibration. 
     Referring now to  FIGS. 3 and 4 ,  FIG. 3  depicts a simplified representation of the sensing components  300  of an example inventive proximity and touch sensing; and  FIG. 4  depicts a schematic representation of a new proximity and touch sensing system using those sensing components. The present illustrative system operates in two distinct modes, a first mode for sensing proximity, and a second mode for sensing actual touch with a contact surface. Once proximity is sensed and evaluated to suggest that touch is likely, or imminent, one or more connections to the sensing components are switched to facilitate evaluating touch rather than proximity. 
     The determination that touch is likely or imminent may be established at a reference by which some further action or command (such as a transition from one state to another) is desired, based on the detected proximity. Touch will be sensed through a direct capacitive measurement resulting from deflection of the contact surface toward a reference electrode. A system for making this form of touch measurement is described in U.S. patent application Ser. No. 12/257,956, entitled Disappearing Button or Slider, and filed Oct. 24, 2008, on behalf of Leung and David Amm, and assigned to the assignee of the present application. This co-pending application is incorporated herein by reference for all purposes. As described in that application, in one implementation, a laptop, as depicted in  FIG. 9  at  900 , can have a surface, such as a lid  902 , having an invisible “button”  904  that functions through capacitive sensing; and touch with such a “button” can provide a number of possible functions, such as displaying otherwise invisible status indicators  906  (such as for wi-fi strength or battery level); or signaling a component of the laptop or an associated external component to “wakeup” from a closed-lid “sleep” mode to a closed-lid “active” mode. Invisible button  904  and invisible status indicators  906  can employ invisible holes and backlighting to make them selectively visible to a user. 
     For example, sensing a touch, such as with a virtual “button”  904  when a laptop computer is in the closed-lid sleep mode, can wake up an external monitor (not shown), sync an iPod or iPhone (not shown) with the laptop computer  900 , or install software to the laptop computer while lid is closed. In other implementations, touch with such an invisible button can shutdown the laptop computer from the closed-lid sleep or closed-lid active modes. Similarly, such invisible touch sensing controls could be used to control music or video played from the computer; such as through invisible controls for rewind, play and fast forward, as well as volume. Invisible holes can 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.); and the holes can be backlit, as described herein. In some examples, invisible touch controls can be contextual, having different functions dependent on an operating state of the device. As noted in the referenced application, the touch sensing controls could also be implemented as a track pad, with a large number of touch-sensing locations. 
     Also as described in the referenced application, and as depicted in  FIGS. 7A-B  and  8 , the ability of a “button” or “slider” location  702 ,  802  to be invisible, but to selectively become visible can be achieved through tiny micro-perforations  704  formed in the surface that can be illuminated by backlighting such as through LEDs under the micro-perforations. The capacitive proximity sensing described herein can advantageously be used to trigger such invisible contact locations becoming visible once a user&#39;s hand (for example) nears the location, and to also then enable those locations to then sense touch from the user. The selective illumination of virtual buttons or sliders can be used both the provide guidance to a user as to where to provide an input, and as to what the function of the input will be. Additionally, where the result of the input is to provide information of the system status, or to update information data on the computer, indications of the status parameter, or of the presence of updated data, can be provided through use of selective illumination through the micro-perforations. An example of providing such indications in this manner is depicted in  FIG. 9  herein. 
     For simplicity of explanation of the depicted subject matter, the proximity and touch sensing components are again described as implemented in an enclosure, indicated generally at  302 , that is constructed similarly to enclosure  102  of  FIG. 1 , with the exception that enclosure  302  includes multiple sensing regions, two of which are depicted in  FIG. 3  at  314  and  316 , rather than the single sensing region  114  of  FIG. 1 . Thus, enclosure  302  will again be described as being formed of metal components including lid  304  and lower section  306 , which are insulated from one another through an insulative gasket  308 . The description relative to  FIG. 1  of the need for other insulating components (not depicted) between the lid and the lower section is also applicable here. The multiple sensing regions may be of virtually any desired configuration, including for example, configurations ranging from individual virtual “buttons,” to regions forming a virtual “slider,” to a virtual keyboard, keypad or trackpad. 
     As with the system of  FIG. 1 , each sensing region  314 ,  316  is defined by a respective recess  328 ,  330  which will preferably leave a thickness of metal in the sensing region  318 ,  320  of approximately the previously described dimensions. Additionally, a respective reference electrode  322 ,  324  is disposed in each recess  328 ,  330 , and in spaced relation to a proximate surface of sensing region  314 ,  316 . In many examples in accordance with this basic description, it will be preferable for electrodes  322 ,  324  to be supported independently of the proximate surface in each sensing region  314 ,  316 . Additionally, for many such examples it will also be preferable to have either a number of conductive connections to individual respective sensing regions, or to have a number electrodes  322 ,  324  coupled to one another. Accordingly, in sensing components  300 , each electrode  322 ,  324  is supported by a substrate, such as a printed circuit board  326 . Printed circuit board  326  facilitates supporting each electrode  322 ,  324  in fixed, spaced relation to each sensing region. Again, as with the system of  FIG. 1 , the spaced relationship between each electrode  322 ,  324 , and a respective surface of sensing regions  314 ,  316  may be established merely by an air gap  328 ,  330  and/or there may be a dielectric layer  332 ,  334  within the recess  328 ,  330 . 
     Referring now primarily to  FIG. 4 , the figure schematically depicts proximity and touch sensing system  400  including the sensing components of  FIG. 3 . Elements depicted in  FIG. 3  have been numbered similarly in  FIG. 4 . As depicted, each electrode  322 ,  324 ,  402  cooperatively forms a respective capacitor with top plate  304  (C t1 , C t2 ), and each electrode  322 ,  324 ,  402  is coupled to a respective input of capacitance sensor  404  (which may of the same type, for example, as capacitance sensor  126  of  FIGS. 1-2 ). Thus, again, each reference electrode is coupled to a high impedance at DC to ground. In this example, the output  406  of capacitance sensor  404  is coupled to a controller  408 , which may be used to initiate various system functions in response to the signal from capacitance sensor  404 . The same functionality may, of course, be provided by another controller in the associated electronic device  416 . Output  406  is also coupled to a switch controller  409  which is responsive to the capacitance measurement signal from capacitance sensor  404 , or to a control signal from controller  408 , to selectively open or close a switch  410  to selectively apply a voltage of a desired polarity to the gate of a field effect transistor (FET)  412  placed to selectively couple lid  304  to ground. Although switch  410  is depicted as a mechanical switch, those skilled in the art will appreciate that it will, in most embodiments, be implemented through a solid-state switch such as a FET switch. 
     Referring now also to  FIG. 5 , that figure depicts an example flow chart  500  for one possible operational mode for the system of  FIGS. 3 and 4 . In operation of proximity and touch sensing system  400 , the system will normally start in a proximity sensing mode  502 . In this mode, the lid  304  is at a floating potential (as described in relation to  FIG. 1 ), by virtue of FET switch  412  being open. 
     At some point, the system will detect a change in capacitance  504 . As described relative to  FIGS. 1 and 2 , the presence of an external potential source proximate lid  304  will generate a capacitance (Ct+Cprox) at one or more sensing regions  314 ,  316  in lid  304 , and that capacitance will be sensed by capacitance sensor  404 . At some point, the sensed capacitance from capacitance sensor  404  will be evaluated  506  to determine is contact with lid  304  is likely. The sensed capacitance may be evaluated within controller  408  or within switch controller  409 , preferably in reference to some parameter of the sensed capacitance, such as by comparison to either a reference capacitance (e.g., as a relative magnitude), or in response to a rate of change of the sensed change in capacitance; and the system will determine that the determined capacitance indicates that a contact with lid  304  is likely or imminent (as at  508 ). Until that determination of likely contact is made  508  (i.e., so long as the system determines that contact is not likely, as at  516 ), the system will remain in capacitive sensing mode  518 . 
     When such determination is made, this example system will switch to touch sensing mode  510 . To achieve this change, switch controller  409  will actuate to close switch  410 , thereby providing a selected voltage to the gate of FET switch  412 , and closing the switch  412  and electrically coupling lid  304  to ground. This coupling places the sensing mechanism in touch sensing mode. 
     A subsequent touch with the surface will generate one or more touch input signals  512 . This is achieved by touch with any of sensing regions  314 ,  316  causing some degree of physical deflection of the sensing region, thereby reducing the distance between the capacitor plates formed by the respective electrode  322 ,  324  and the proximate surface of the sensing region  314 ,  316 , thereby resulting in a change in the capacitance which may be detected by capacitance sensor  404 , which will then output a signal representing a touch contact at that location. 
     With the multi-channel capacitance sensor as described, the presence or absence of touch at multiple locations (either simultaneously or sequentially) may be sensed (at  512 ), and the appropriate functionality implemented  514 . As noted herein, that touch contact signal may be used by system controller  408  to implement the desired functionality in the associated electronic device  416 . Once touch contacts are no longer sensed, a timer may be used to generate a timeout signal, after which the system will preferably be returned to proximity sensing mode through deactivation of switch  410 , and thus also switch  412 , returning lid  304  to its floating state. As one example, a sensed contact at another location could result in a reset of the timer function. As an alternative, in touch sensing mode, Ctprox may be considered as the sum of sensory inputs to the multiple channels of capacitance sensor  404 , and, for example, the sum of those signals can be evaluated relative to a minimum (Cmin) to determine an apparent absence of a user, and only then to start the timer. 
       FIG. 6  depicts a simplified block diagram of a machine in the example form of an electronic device, such as a computing device, within which a set of instructions, for causing the machine to perform any one or more of the methodologies discussed herein, may be executed. In alternative embodiments, the machine may be connected (e.g., networked) to other machines. In a networked deployment, the machine may operate in the capacity of a server or a client machine in client-server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. While only a single machine is illustrated, the term “machine” shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. 
     Example computing device  600  includes at least one processor  602  (e.g., a central processing unit (CPU), a graphics processing unit (GPU) or both), main system memory  604  and static memory  606 , which communicate with each other via bus  608 . In some examples, the computing device will include multiple processors, wherein one is an auxiliary processor, that will preferably be a relatively low power device compared to the primary, or “system” processor(s), that may be powered on at almost all times other than complete system shutdown (such as in a “sleep” mode; for example, a mode in which the state of the system is preserved, but other operations by the system processor are disabled). Such an auxiliary processor will be used in such example systems to control the sensing circuitry herein even when the computing device is in a “closed lid” state, and/or in sleep mode. Additionally, such an auxiliary processor may be used in at least some of these example systems to implement various touch-responsive functionalities while still in the closed-lid state or a sleep state. For example, in addition to functions described elsewhere herein, such closed lid operations can include implementing wired or wireless communication systems to check for updated information data, such as for emails received, stock quotes, sports scores, etc.; checking on parameters of the system status (such as wi-fi signal strength or battery status); and displaying either the information or an indication that updated information is available, through the closed lid, such as through illuminating some portion of the micro-perforation regions, such as at or near the invisible buttons or sliders. 
     Computing device  600  may further include video display unit  610  (e.g., a plasma display, a Liquid Crystal Display (LCD), Organic Light Emitting Diode (OLED) display, Thin Film Transistor (TFT) display, or a cathode ray tube (CRT)). Computing device  600  also includes optical media drive  628 , a user interface (UI) navigation, or cursor control, device  614  (e.g., a mouse), disk drive unit  616 , signal generation device  618  (e.g., a speaker), optical media drive  628 , and network interface device  620 . 
     Disk drive unit  616  includes machine-readable medium  622  on which is stored one or more sets of instructions and data structures (e.g., software  624 ) embodying or utilized by any one or more of the methodologies or functions described herein. Software  624  may also reside, completely or at least partially, within main system memory  604  and/or within processor  602  during execution thereof by computing device  600 , with main system memory  604  and processor  602  also constituting machine-readable, tangible media. Software  624  may further be transmitted or received over network  626  via network interface device  620  utilizing any one of a number of well-known transfer protocols (e.g., Hypertext Transfer Protocol (HTTP)). 
     While machine-readable medium  622  is shown in an example embodiment to be a single medium, the term “machine-readable medium” should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches) that store the one or more sets of instructions. The term “machine-readable medium” shall also be taken to include any medium that is capable of storing or encoding a set of instructions for execution by the machine and that cause the machine to perform any one or more of the methodologies of the present application, or that is capable of storing, encoding or carrying data structures utilized by or associated with such a set of instructions. The term “machine-readable storage medium” shall accordingly be taken to include all forms of solid-state memories, optical and magnetic media, and other structures facilitating reading of data stored or otherwise retained thereon. 
     Many additional alternative constructions may be envisioned to those skilled in the art having the benefit of the teachings of this disclosure; and many additional modifications and variations may be made in the techniques and structures described and illustrated herein. For example, the example capacitance sensor device identified operates by comparing a reference value to ground. Many other types of capacitance sensors may be used, with appropriate modifications apparent to those skilled in the art having the benefit of the present disclosure. For example, capacitance sensors might be used that measure capacitance directly between two sensing members. As one example of a modification to facilitate that type of capacitance sensor, the outer conductive member of each sensing location might be individually coupled to the outer plate through a respective FET switch. Accordingly the scope of the invention should be expressly understood to be limited only by the scope of all claims are supported by the present specification, as well as all equivalents of such claims.

Metadata:
Filing Date: 20161118
Publication Date: 20191022
Grant Date: 20191022
Priority Date: 20081024
Inventors: PANCE, ALEKSANDAR
LEUNG, OMAR S.
AMM, DAVID T.
Assignee: APPLE INC
CPC Classifications: [{"code": "H03K17/975", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/9622", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/169", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/98", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04104", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/169", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03547", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03547", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04108", "inventive": false, "first": false, "tree": "[]"}, {"code": "H03K17/975", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/955", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/169", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/962", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K2217/96077", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/9622", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K2217/96077", "inventive": false, "first": false, "tree": "[]"}, {"code": "H03K17/955", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/955", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/9622", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03547", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1643", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/975", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/98", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": true, "tree": "[]"}, {"code": "H03K17/98", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K2217/96077", "inventive": false, "first": false, "tree": "[]"}, {"code": "H03K17/962", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/962", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1643", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K2217/96077", "inventive": false, "first": false, "tree": "[]"}, {"code": "H03K17/975", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/9622", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/955", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03547", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/98", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04108", "inventive": false, "first": false, "tree": "[]"}, {"code": "H03K17/962", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04104", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/169", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": true, "tree": "[]"}, {"code": "H03K2217/96077", "inventive": false, "first": false, "tree": "[]"}, {"code": "H03K17/98", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/975", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/955", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0443", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/03547", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/169", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": false, "tree": "[]"}, {"code": "H03K17/9622", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0443", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0443", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0416", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 42985347