Patent Document

CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims benefit of U.S. Provisional Application No. 61/551,350, filed Oct. 25, 2011, which is hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates power saving systems for mobile devices and more particularly, to systems for detecting the closure of a cover on a mobile device. 
     BACKGROUND OF THE INVENTION 
     Compact and lightweight notebook, laptop computers have become increasingly popular due to their portability. In general, such a portable computer is composed of a main body having a keyboard and a lid, where the lid is hingedly attached to the main body of the portable computer. A flat panel display is typically mounted on the lid. Or in some instances it could be said that the flat panel display forms a lid covering the keyboard of the main body. Usually, the lid is closed when the portable computer is not in use. Many of these devices include mechanisms, typically mechanical, to detect the closure of the lid. These detection mechanisms are tied to power saving circuitry, hardware or software, to effectuate a power savings mode when the lid is detected as closed. Similar detection and power savings mode have been employed in flip phones. 
     However, the aforementioned mechanical lid detection mechanism do not work for tablet type devices that do not have an integrated cover. 
     SUMMARY OF THE INVENTION 
     The present invention helps improve power consumption by providing the ability to detect whether a cover is placed on top of Infrared, IR, touch device such as an eReader or a tablet device. While the cover is in the open state, a certain amount of the light transmitted by the IR transmitters is directed upward and away from the IR receivers in the device. When the cover is closed, this light is reflected off of the cover and is incident on the IR receivers. The system of the present invention recognizes this increased level of received IR light and determines that the cover is in a closed position. Having made such a determination that the cover is placed on the device, the device&#39;s power savings system can switch to an appropriate power saving mode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For the purposes of illustrating the present invention, there is shown in the drawings a form which is presently preferred, it being understood however, that the invention is not limited to the precise form shown by the drawing in which: 
         FIG. 1  illustrate a touch screen device with an IR detection system; 
         FIG. 2  depicts a device incorporating the present invention with the cover in an open state; 
         FIG. 3  depicts a device incorporating the present invention with the cover in a closed state; 
         FIG. 4  is a flow chart illustrating a method an embodiment of the present invention; and 
         FIG. 5  illustrates the components of an exemplary device. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present inventor discovered that there is a clear difference in IR level reading on a touch screen device when the device&#39;s display is covered and uncovered. Further investigation revealed that the increased IR levels were due to reflection off of the cover of the device when it was in a closed state. It was recognized that this behavior can be exploited to serve as a mechanism to detect whether a cover is in a closed or opened state, without additional hardware, and thus improve power savings in a mobile device. 
     In the preferred embodiment, the touch screen device is a tablet device, preferably an e-Reader device. Although these devices typically do not have an integrated cover, many users purchase a protective cover as an accessory to protect the device. These protective covers can take several forms such as a sleeve or a portfolio type cover. 
     The present invention provides a simple and inexpensive mechanism to detect whether a cover is on or off of a device equipped with an optical touch interface such as an IR based touch interface. The ability to detect when the cover is closed reduces power consumption. Power consumption can be reduced by automatically switching the device to low-power mode when the cover is detected to be in the closed position, without any user action required. This convenient automation saves the user time by not having to manually press a button, mechanical or virtual, to suspend the device into the power savings mode. Further it saves power by switching into the power savings mode more quickly than the conventional time-out mechanisms, which wait for a predetermined amount of time without a user input to switch into the power savings mode. 
       FIG. 1  depicts a basic IR-based touch system on a device  130 . IR Light Emitting Diodes, LEDs, e.g.,  301 ,  303 ,  305 , and photodiodes (PD), e.g.,  304 ,  306 ,  308 , work together to detect touch objects  302  which are typically a finger or stylus. The IR LEDs are located on two adjacent sides of the device  130 , while the PDs are located on the opposite sides of the device  130  to detect the light emitted by the LEDs. 
     An IR LED, e.g.,  305 , emits and IR beam  320  and a photodiode, e.g.,  308 , detects the beam  320 . This is the case when there is nothing touching the display, i.e., no touch object  302  to block the IR light beam  320 . However, when a user touches the screen using a finger or another touch object  302 , IR light from LED  303  is blocked by the object  302  and redirects the IR light  307  away from PD  304 . As a result of object  302  blocking the light from LED  303 , PD  304  detects a significant drop in the light level. At the same time, a similar scenario is happening on the y-axis: Light emitted by LED  301  is blocked by the touch object, e.g., finger or stylus,  302  resulting in a huge drop in the light level reading at PD  306 . Based on the detection of the absence of light by PDs  304  and  306 , the system can determine the x and y coordinate location of the touch of object  302 . 
     The present invention operates on the basis that when a cover is placed over the touch surface of the device  130 , light emitted by the LEDs that is normally not detected by photodiodes, is redirected by the cover and eventually onto photodiodes PD. 
       FIG. 2  illustrates the operation of the system of the present invention when a cover ( 106  in  FIG. 3 ) is not covering the device  130 , e.g., in an open position. As illustrated in this Figure, while most of the light  102  emitted from LED  104  hits PD  101  there are scatter light beams  103  from LED  104  never reach photodiode  101 . 
     However, when the cover  106  is place on the device  130 , e.g., in a closed position, as depicted in  FIG. 3 , the scatter light beams  103  now bounce off the cover  106  and make their way onto photodiode  101  on the other side. As a result, the photodiodes detect an IR reading in both x-axis and y-axis that is elevated from the state when the cover  106  is not present. Once the system detects the elevated levels of detected IR light, it determines that the cover has been closed on top of the device  130  and informs the power saving module to go into a power saving mode. 
     As appreciated by those skilled in the art, approximately the same result of increased light detection will occur if the user places the device  130 , screen side down on a flat surface. e.g., a desk or table top. Like a cover, the desktop will reflect the light back toward the screen and the detectors and result in a greatly increased proportion of detected light. The present invention thus allows the user to place the device  130  face down on a table top in order to invoke the power saving mode without having to close a cover over the screen of the device  130 . 
     In an alternative embodiment of the present invention, the cover  106  actually has an extension that protrudes toward the screen of the device  130  and blocks the light from LEDs  104  from reaching photo detectors  101 . This is essentially the opposite of the embodiment described above in which the light is greatly increased by the closing of the cover in order to invoke the power saving mode. In the this alternative embodiment, the cover blocks substantially all of the light from the LEDs  104  so that there is a substantial decrease in the light detected by the PDs  106 . The percentage of light blocked by the cover projection is significantly greater that any normal object detection, e.g., a finger. The system of the present invention interprets this greatly diminished light detection as an indication that the special cover has been closed and accordingly enters the power saving mode. 
       FIG. 4  is a flowchart depicting a preferred embodiment of the method of the present invention. In act  300 , the LEDs and PDs in the device  130  are activated and begin operating. Typically this act occurs when the device is turned on or ‘woken up’ from a power savings sleep state. In act  305 , the system obtain s baseline of light received by the PDs in a nominal state when there is no cover in place. This baseline is preferably established when the device  130  is turned on, woken up and periodically to take into account environmental conditions that may effect the IR detection, e.g., temperature. Changes in ambient light, e.g., going from indoors to sunlight outdoors, would not typically effect the IR detection as the system is tuned to transmit and receive IR frequencies that do not change with changing ambient conditions. 
     In step  315 , the main routine starts with the system monitoring the light levels detected by the PDs for changes in these levels. In act  315 , a change in a light level is detected. In act  320  is determined if the change is an increase or a decrease in the light level. If the change is a decrease in the detected light levels, the assumption is that an object, e.g., a user&#39;s finger, is blocking the light and in act  325 , the normal processing for touch detection takes place. 
     If there is an increase in the detected light level, the system then determines if was caused by a cover being placed over the device. Two ways the system accomplishes this is ensure that the increase in detected light level is substantially uniform over the PDs, act  330 , and that the increased light detection occurs over some predetermined period of time, e.g., 30 seconds, a minute, act  335 . These two tests  330  and  335  are intended to filter out spurious, random and isolated increases in the light. For example, if the user momentarily lays her whole hand, or a paper over the device, this will result in a temporary increase in the light detected by a substantial number or perhaps all of the PDs. The system should be able to determine, through the above two tests, that this incident was not the closing of the cover, but some other event. 
     If it is determined that the increase in light is in fact due to the closing of the cover, the system enters the power savings mode in act  340 . The system will stay in this mode until it is reactivated, ‘woken up’, at which point the process illustrated in this Figure is repeated. 
       FIG. 5  illustrates an exemplary device  130  employing the present invention. As appreciated by those skilled the art, the device  130  can take many forms capable of operating the present invention. In a preferred embodiment the device  130  is a mobile electronic device, and in an even more preferred embodiment device  130  is an electronic reader device, such as a tablet device. Electronic device  130  can include control circuitry  500 , storage  510 , memory  520 , input/output (“I/O”) circuitry  530 , communications circuitry  540 , and display  550 . In some embodiments, one or more of the components of electronic device  130  can be combined or omitted, e.g., storage  510  and memory  520  may be combined. As appreciated by those skilled in the art, electronic device  130  can include other components not combined or included in those shown in this Figure, e.g., a power supply such as a battery, an input mechanism, etc. 
     Electronic device  130  can include any suitable type of electronic device. For example, electronic device  130  can include a portable electronic device that the user may hold in his or her hand, such as a digital media player, a personal e-mail device, a personal data assistant (“PDA”), a cellular telephone, a handheld gaming device, a tablet device or an eBook reader. As another example, electronic device  130  can include a larger portable electronic device, such as a laptop computer. 
     Control circuitry  500  can include any processing circuitry or processor operative to control the operations and performance of electronic device  130 . For example, control circuitry  500  can be used to run operating system applications, firmware applications, media playback applications, media editing applications, or any other application. Control circuitry  500  can drive the display  550  and process inputs received from a user interface, e.g., the touch screen display  550 . 
     Cover Sensing component  505  operates as described above to detect the presence and absence of a cover of the device  130 . Cover Sensing component  505  operates with the IR sensing capabilities of the touch screen  550 , I/O circuitry  530  and control circuitry  500  to place the device  130  in a power savings mode when the Cover Sensing component  505  detects that the cover is closed. The process for effectuating the power savings mode is accomplished by the control circuitry and is well known in the art. 
     Storage  510  can include, for example, one or more computer readable storage mediums including a hard-drive, solid state drive, flash memory, permanent memory such as ROM, magnetic, optical, semiconductor, paper, or any other suitable type of storage component, or any combination thereof. Storage  510  can store, for example, media content, e.g., eBooks, music and video files, application data, e.g., software for implementing functions on electronic device  130 , firmware, user preference information data, e.g., content preferences, authentication information, e.g., libraries of data associated with authorized users, transaction information data, e.g., information such as credit card information, wireless connection information data, e.g., information that can enable electronic device  130  to establish a wireless connection, subscription information data, e.g., information that keeps track of podcasts or television shows or other media a user subscribes to, contact information data, e.g., telephone numbers and email addresses, calendar information data, and any other suitable data or any combination thereof. The instructions for implementing the functions of the present invention may, as non-limiting examples, comprise software and/or scripts stored in the computer-readable media  510   
     Memory  520  can include cache memory, semi-permanent memory such as RAM, and/or one or more different types of memory used for temporarily storing data. In some embodiments, memory  520  can also be used for storing data used to operate electronic device applications, or any other type of data that can be stored in storage  510 . In some embodiments, memory  520  and storage  510  can be combined as a single storage medium. 
     I/O circuitry  530  can be operative to convert, and encode/decode, if necessary analog signals and other signals into digital data. In some embodiments, I/O circuitry  530  can also convert digital data into any other type of signal, and vice-versa. For example, I/O circuitry  530  can receive and convert physical contact inputs, e.g., from a multi-touch screen, i.e., display  550 , physical movements, e.g., from a mouse or sensor, analog audio signals, e.g., from a microphone, or any other input. The digital data can be provided to and received from control circuitry  500 , storage  510 , and memory  520 , or any other component of electronic device  130 . Although I/O circuitry  530  is illustrated in this Figure as a single component of electronic device  130 , several instances of I/O circuitry  530  can be included in electronic device  130 . 
     Electronic device  130  can include any suitable interface or component for allowing a user to provide inputs to I/O circuitry  530 . For example, electronic device  130  can include any suitable input mechanism, such as a button, keypad, dial, a click wheel, or a touch screen, e.g., display  550 . In some embodiments, electronic device  130  can include a capacitive sensing mechanism, or a multi-touch capacitive sensing mechanism or an IR sensing mechanism as described above. 
     In some embodiments, electronic device  130  can include specialized output circuitry associated with output devices such as, for example, one or more audio outputs. The audio output can include one or more speakers, e.g., mono or stereo speakers, built into electronic device  130 , or an audio component that is remotely coupled to electronic device  130 , e.g., a headset, headphones or earbuds that can be coupled to device  130  with a wire or wirelessly. 
     Display  550  includes the display and display circuitry for providing a display visible to the user. For example, the display circuitry can include a screen, e.g., an LCD screen, that is incorporated in electronics device  130 . In some embodiments, the display circuitry can include a coder/decoder (Codec) to convert digital media data into analog signals. For example, the display circuitry or other appropriate circuitry within electronic device  1  can include video Codecs, audio Codecs, or any other suitable type of Codec. 
     The display circuitry also can include display driver circuitry, circuitry for driving display drivers, or both. The display circuitry can be operative to display content, e.g., media playback information, application screens for applications implemented on the electronic device  130 , information regarding ongoing communications operations, information regarding incoming communications requests, or device operation screens, under the direction of control circuitry  500 . Alternatively, the display circuitry can be operative to provide instructions to a remote display. 
     Communications circuitry  540  can include any suitable communications circuitry operative to connect to a communications network and to transmit communications, e.g., data from electronic device  130  to other devices within the communications network. Communications circuitry  540  can be operative to interface with the communications network using any suitable communications protocol such as, for example, Wi-Fi, e.g., a 802.11 protocol, Bluetooth, radio frequency systems, e.g., 900 MHz, 1.4 GHz, and 5.6 GHz communication systems, infrared, GSM, GSM plus EDGE, CDMA, quadband, and other cellular protocols, VoIP, or any other suitable protocol. 
     Electronic device  130  can include one more instances of communications circuitry  540  for simultaneously performing several communications operations using different communications networks, although only one is shown in this Figure to avoid overcomplicating the drawing. For example, electronic device  130  can include a first instance of communications circuitry  540  for communicating over a cellular network, and a second instance of communications circuitry  540  for communicating over Wi-Fi or using Bluetooth. In some embodiments, the same instance of communications circuitry  540  can be operative to provide for communications over several communications networks. 
     In some embodiments, electronic device  130  can be coupled to a host device such as remote servers for data transfers, synching the communications device, software or firmware updates, providing performance information to a remote source, e.g., providing riding characteristics to a remote server, or performing any other suitable operation that can require electronic device  130  to be coupled to a host device. Several electronic devices  130  can be coupled to a single host device using the host device as a server. Alternatively or additionally, electronic device  130  can be coupled to several host devices, e.g., for each of the plurality of the host devices to serve as a backup for data stored in electronic device  130 . 
     Although the present invention has been described in relation to particular embodiments thereof, many other variations and other uses will be apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the gist and scope of the disclosure.

Technology Category: 3