Patent Publication Number: US-11650700-B2

Title: Information handling system stylus having an ultrasonic location aid

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates in general to the field of portable information handling system stylus devices, and more particularly to an information handling system stylus having an ultrasonic location aid. 
     Description of the Related Art 
     As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems. 
     Portable information handling systems integrate processing components, a display and a power source in a portable housing to support mobile operations. Portable information handling systems allow end users to carry a system between meetings, during travel, and between home and office locations so that an end user has access to processing capabilities while mobile. Tablet configurations typically expose a touchscreen display on a planar housing that both outputs information as visual images and accepts inputs as touches. Convertible configurations typically include multiple separate housing portions that couple to each other so that the system converts between closed and open positions. For example, a main housing portion integrates processing components and a keyboard and rotationally couples with hinges to a lid housing portion that integrates a display. In clamshell configuration, the lid housing portion rotates approximately ninety degrees to a raised position above the main housing portion so that an end user can type inputs while viewing the display. After usage, convertible information handling systems rotate the lid housing portion over the main housing portion to protect the keyboard and display, thus reducing the system footprint for improved storage and mobility. In many instances, convertible information handling systems will rotate the housing portions 360 degrees to a “tablet” position that exposes a touchscreen display for use as a tablet. 
     One tool that enhances the use of portable information handling systems is a stylus that supports end user “writing” inputs at a touchscreen display similar to writing with a pen on a piece of paper. An active stylus has an internal battery that powers internal processing components and an active writing tip, which increases the accuracy of touch detection. In many instances, active stylus devices include a BLUETOOTH or other wireless interface that coordinates stylus and information handling system interactions. Many stylus devices integrate expensive components that can make a stylus an expensive device to lose. Generally, a stylus can include one or both of an audible locator or a wireless locator. Audible locators are typically buzzers included in the stylus that direct an audible sound out an opening for an end user to hear. One difficulty with this approach is that the loudness of the buzzer can vary depending upon the orientation of the audio opening in the stylus housing so that a stylus facing in the wrong direction or covered by an object will be difficult to hear. Another difficulty is that the small size of the stylus, typically the size of a writing pen, limits the size of an integrated buzzer so that the sound output is limited, often to roughly 60 dB equivalent to normal conversation. In low ambient light conditions, the buzzer provides a general location, but the precise location is difficult to determine. Wireless location, such as with a TILE type of functionality, helps to confirm the general location of a lost stylus but typically cannot provide a precise location. In addition, using a wireless location logic tends to increase power consumption at the stylus while the radio monitors for radio signals and sends position reports. 
     SUMMARY OF THE INVENTION 
     Therefore, a need has arisen for a system and method which aids location of a stylus relative to an information handling system. 
     In accordance with the present invention, a system and method are provided which substantially reduce the disadvantages and problems associated with previous methods and systems that aid in location of a stylus relative to an information handling system. A haptic film disposed in the stylus generates vibration at a frequency selected from a range of frequencies based upon an estimate of the distance between the information handling system and stylus. A high frequency haptic film vibration can generate an ultrasonic sound that an information handling system and stylus use to determine distance and vector information for tracking the stylus and determining how much haptic film vibration is desired to aid an end user in noticing the location of the stylus, such as with vibration noise. 
     More specifically, an information handling system processes information with processing components disposed in a housing, such as a portable planar tablet housing. A processor cooperates with a memory to execute instructions and present visual images at a touchscreen display configured to accept touch inputs by a stylus having an active writing tip and a wireless personal area network (WPAN) radio to communicate with the information handling system. A stylus locator having instructions stored in non-transient memory that execute on one or more processing resources to aid in location of the stylus by an end user, such as in response to an end user inquiry for the location of the stylus. A haptic film disposed at the stylus exterior vibrates at a frequency selected from a range of frequencies based upon a distance estimate between the stylus and information handling system, such as a distance estimate provided by wireless communication. The haptic film and a speaker on the information handling system may also provide ultrasonic noise between the stylus and information handling system that communicates messages, such as a time stamp, to allow distance and directional information of the stylus relative to the information handling system. In one embodiment, a light integrated in the stylus is selectively illuminated based upon ambient conditions detected at the information handling system or stylus. 
     The present invention provides a number of important technical advantages. One example of an important technical advantage is that a stylus position relative to an information handling system is provided with minimal power consumption at the stylus and minimal distraction to end users. For example, stylus vibration frequency and amplitude to provide a location aid to an end user is adjusted based upon an estimated distance between the stylus and information handling system so that less noise is generated at shorter distances and increased noise is generated at longer distances. The use of reduced vibration frequency and amplitude at shorter distances helps to reduce power consumption and also disruption to other nearby users. As another example, ultrasonic vibration provides location direction and distance of the stylus relative to the information handling system without disruption to an end user by an audible sound and allows tracking of the stylus position by an information handling system. Another example is that an LED light on the stylus is used for location only when sensed ambient light indicates that LED illumination will provide an effective location aid. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention may be better understood, and its numerous objects, features and advantages made apparent to those skilled in the art by referencing the accompanying drawings. The use of the same reference number throughout the several figures designates a like or similar element. 
         FIG.  1    depicts a block diagram of an information handling system and stylus having a location indication provided by haptic vibration at a frequency selected based upon a distance between the information handling system and stylus; 
         FIGS.  2 ,  2 A,  2 B,  2 C and  2 D  depict an isometric transparent view of the stylus configured with a haptic film at an exterior surface and an LED that provides illumination for location of the stylus; 
         FIGS.  3 A,  3 B and  3 C  depict examples of sound and light generated at a stylus to aid in location of the stylus; 
         FIGS.  4 ,  4 A,  4 B and  4 C  depict an example stylus that integrates a microphone and haptic film to aid in location of the stylus; 
         FIG.  5    depicts a flow diagram of a process for locating a stylus with variable haptic frequency noise based upon distance to the stylus; 
         FIG.  6    depicts a flow diagram of a process for locating a stylus with illumination based upon ambient light detection; 
         FIG.  7    depicts a flow diagram of a process for locating a stylus with vibration of a haptic film of the stylus detected by a microphone of the information handling system; and 
         FIG.  8    depicts a flow diagram of a process for locating a stylus with ultrasonic sound detected at a microphone of the stylus. 
     
    
    
     DETAILED DESCRIPTION 
     An information handling system and stylus coordinate to provide a location vibration at the stylus that varies based upon a distance between the information handling system and stylus. For purposes of this disclosure, an information handling system may include any instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, or other purposes. For example, an information handling system may be a personal computer, a network storage device, or any other suitable device and may vary in size, shape, performance, functionality, and price. The information handling system may include random access memory (RAM), one or more processing resources such as a central processing unit (CPU) or hardware or software control logic, ROM, and/or other types of nonvolatile memory. Additional components of the information handling system may include one or more disk drives, one or more network ports for communicating with external devices as well as various input and output (I/O) devices, such as a keyboard, a mouse, and a video display. The information handling system may also include one or more buses operable to transmit communications between the various hardware components. 
     Referring now to  FIG.  1   , a block diagram depicts an information handling system  10  and stylus  38  having a location indication provided by haptic vibration at a frequency selected based upon a distance between the information handling system and stylus. In the example embodiment, information handling system  10  has a tablet configuration with processing components disposed in a portable planar housing  12  having a display  34  coupled over the processing components. A motherboard  14  couples to the interior of housing  12  and includes wirelines for communication between the processing components. A central processing unit (CPU)  16  executes instructions that process information in cooperation with a random access memory (RAM)  18  that stores the information and instructions. A solid state drive (SSD)  20  provides non-transient memory that stores the instructions and information during power down periods. For example, at power up of information handling system  10  firmware instructions of an embedded controller  24  execute to retrieve an operating system and applications from SSD  20  to RAM  18  for processing by CPU  16  to generate visual information for presentation at a display  34  with additional processing provided by a graphics processing unit (GPU)  22 . Embedded controller  24  provides management functions for the processing components disposed in the housing, such as power management, thermal management and interactions with peripheral devices and sensors. For instance, in the example embodiment, an ambient light sensor (ALS)  26  detects ambient light conditions at information handling system  10  and communicates the ambient light conditions to embedded controller  24 , which makes the ambient light conditions available to CPU  16 . Embedded controller  24  manages interactions by CPU  16  with a microphone  28 , which captures sounds as electronic signals, and with a speaker  30 , which plays electronic signals as sounds. A wireless network interface card (WNIC)  32  includes a radio to support wireless communications with external devices, such as through wireless local area networks (WLANs) and wireless personal area networks (WPANs) like Bluetooth. 
     In the example embodiment, information handling system  10  communicates through the radio of WNIC  32  with stylus  38  that supports end user touch inputs through a writing tip  40  that touches display  34 . Stylus  38  holds processing components to support touch inputs in a pen-shaped housing  52 . A microprocessing unit (MCU)  42  has a processing resource to execute instructions stored in integrated non-transitory memory. MCU  42  interfaces with a haptic film  44  that vibrates at a frequency selected from a range of frequencies, as described in greater depth below. A light emitting diode (LED)  46  interfaces with MCU  42  to selectively provide illumination. A WNIC  48  includes a radio that provides wireless communication to information handling system  10 , such as with a BLUETOOTH or other wireless personal area network (WPAN). A microphone  50  interfaced with MCU  42  and WNIC  48  detects sounds and converts the sounds to electronic signals that can be communicated to information handling system  10 . Stylus  38  provides a convenient and powerful tool for performing touch inputs to a touchscreen of display  34 , such as for drawing or writing. A difficulty with stylus  38  is that it can tend to get lost after use. Information handling system  10  and stylus  38  coordinate resources to help prevent stylus  38  from becoming lost and that helps to find stylus  38  when out of sight of an end user. Generally, the term “stylus” is used interchangeably herein with the term “pen” as the stylus is a type of pen that writes to an electronic device touchscreen display. 
     In the example embodiment, stylus  38  location for an end user is coordinated by a stylus locator  36  that executes on processing resources of one or more of CPU  16 , embedded controller  24  and MCU  42 . For example, stylus locator  36  is a set of instructions stored in non-transient memory, such as SSD  20  or flash memory of MCU  42 , and executed to coordinate operation of haptic film  44 , microphones  28  and  50 , radios of WNIC  32  and  48 , and speaker  30  so that sounds are generated and detected to aid in end user location of stylus  38 , such as in response to an end user inquiry at a user interface presented at display  34  for the location of stylus  38 . The instructions may be distributed between processing resources as an application, an operating system driver and a firmware module, or in other types of configurations. In one embodiment, haptic film  44  generates a vibration selected from a range of vibration frequencies based upon a distance determined between information handling system  10 , such as a distance estimate determined by radio communications. At short distances of one meter or less, a reduced vibration of 300 Hz may be used that provides adequate noise for an end user to locate stylus  38  while consuming reduced power. At a longer distance, vibration of up to 20 KHz may be used with increased amplitude to generate a greater location noise. Vibrations of greater than 20 KHz may be used to generate ultrasonic noise that is inaudible to an end user but audible by microphones  28  and  50 . Ultrasonic vibrations may provide messages between the stylus and information handling system, such as a time stamp that allows a determination of a distance between the stylus and information handling system with reference to the time of flight for sounds versus the speed of sound. In addition, ultrasonic noise at the stylus provides a directional vector for an information handling system directional microphone to provide tracking of the stylus location when not in use so that the end user inquiry for stylus location may be met with a mapped location even before vibrating the stylus with audible sounds. 
     Referring now to  FIGS.  2 ,  2 A,  2 B,  2 C and  2 D , an isometric transparent view depicts the stylus  38  configured with a haptic film  44  at an exterior surface and an LED  46  that provides illumination for location of the stylus. Haptic film  44  couples at an exterior surface of stylus  38  housing  52  and interfaces with MCU  42  to accept commands to generate vibration at a frequency selected from a range of frequencies, such as based upon a distance estimated between stylus  38  and an information handling system. In the example embodiment, haptic film  44  is covered with a silicon or fabric aesthetic skin  54  that provides a feeling similar to a writing pen. LED  46  is disposed at an end opposite writing tip  40  to provide illumination, such as with a current commanded by MCU  42 .  FIG.  2 A  depicts that LED  46  has a ring light pipe  60  or other transparent or translucent material to pass illumination to the outer surface. An LED circuit board  56  integrates an LED integrated circuit  58  on each of opposing sides to aid in achieving well-distributed illumination about the circumference of housing  52 .  FIG.  2 B  depicts that haptic film  44  includes a ribbon portion that interfaces with MCU  42  to accept a current that generates vibration with selectable frequency and amplitude. By locating haptic film  44  at the exterior surface of housing  52 , vibration generated at the haptic film translates more readily to a surface on which stylus  38  rests, resulting in an amplification of sound generated by the vibration. 
       FIG.  2 C  depicts haptic film  44  separate from stylus  38  housing  52  with a seam that separates to fit around housing  52 . A flexible printed substrate has plural haptic film actuators  62  coupled to an interior surface that generate the vibration in response to application of a current. As an example, haptic film actuator  62  is an electro-active polymer (EAP) material available from KEMET having a blend of high strain and high modulus material that allows flexibility and aligns molecules when voltage is applied to generate at vibration. In one example embodiment, voltage is applied by a first integrated circuit, such as the MICROCHIP HV56020 that provides simultaneous drive of multiple channels, and by a second integrated circuit, such as the MICROCHIP HV56022 that drives additional channels in time slices. By applying different types of alternating current of different frequencies and amplitudes to haptic film  44 , different types of vibrations may be produced.  FIG.  2 D  depicts a cross-sectional view of haptic film  44  as indicated by  FIG.  2 B . Flexible substrate  64  of haptic film  44  at the exterior of stylus housing  52  has a soft covering skin  54  and haptic film actuator  62  at an interior surface to generate vibration. A conforming spacer  66  may be coupled over haptic film actuator  62  to provide a more robust assembly. 
     Referring now to  FIGS.  3 A,  3 B and  3 C , examples depict sound and light generated at stylus  38  to aid in location of the stylus.  FIG.  3 A  depicts stylus  38  with haptic vibrations  68  generated by haptic film  44 , which translate against a support surface, such as table or floor, to generate stylus vibrations  70  that in turn output an amplified sound  72  having sufficient noise level to be heard by an end user within a predetermined distance. The amount of noise output for a haptic film vibration frequency and amplitude depends upon a number of factors, including the location of the haptic film along the length of the stylus housing, the weight of the stylus and the type of underlying support. In order to create the loudest possible sound for a given power expenditure, a voltage form for application to haptic film  44  may be selected that generates a resonate vibration of stylus  38 .  FIG.  3 B  depicts an example of how stylus haptic vibration  68  acts upon an object  74  placed on top of the stylus to generate a stylus vibration  70  though the object  74 , such as a book. Understanding how different environments generate different sounds provides a basis for adjusting vibration generated by the haptic film, such as based upon feedback of the sounds detected through a microphone at the information handling system or stylus or vibrations detected by an accelerometer in the stylus.  FIG.  3    illustrates illumination of LED  46  along with vibration  68  of haptic film to generate stylus vibration  70 . Both the vibration and the illumination consume battery power at the stylus. To minimize the power impact, vibration is adjusted based upon a distance of the stylus to an information handling system, and illumination is limited to situations where ambient light conditions indicated illumination will aid in location of the stylus, such as ambient light detected at the information handling system or stylus. 
     Referring now to  FIGS.  4 ,  4 A,  4 B and  4 C , an example embodiment depicts a stylus  38  that integrates a microphone  76  and haptic film  44  to aid in location of the stylus. Microphone  76  couples at an end of stylus  38  opposite writing tip  40 , such as at a push button used to initiate BLUETOOTH advertisement from stylus  38 . During ordinary usage, microphone  76  provides a convenient tool for an end user to input audible information, which is communicated to an information handling system through the radio.  FIG.  4 A  depicts microphone  76  exposed at the stylus end next to a spring-loaded push button  80  and interfaced through a flexible cable  78  to a circuit board supporting MCU  48 , which provides the audio information captured by microphone  76  to the radio of the WNIC.  FIG.  4 B  depicts a cross-sectional view of microphone  76  to include a MEMS microphone device placed on the end of a launch button  84  biased out by spring  80  against an opening  82  through which sounds enter the microphone. A tactile switch  86  accepts inputs to initiate radio advertising and flexible cable  78  communicates microphone-captured audio information to the MCU.  FIG.  4 C  illustrates that stylus  38  with microphone  50  provides an ability to directly monitor sound generated by vibration and also to detect sounds output by an information handling system. As one example, haptic vibration  68  is provided at a high frequency resulting in amplified sound  72  in an ultrasonic frequency range. Similarly, an information handling system speaker output ultrasonic sound  88  that is detected by microphone  50 . Using ultrasonic sound to communicate between the stylus and information handling system provides positional information of the stylus, such as distance and a direction determined from a directional microphone of the information handling system, without generating audible information detectable by human hearing that can disrupt an end user&#39;s concentration. 
     Referring now to  FIG.  5   , a flow diagram depicts a process for locating a stylus with variable haptic frequency noise based upon distance to the stylus. The process starts at step  90  with a portable information handling system  10  scanning with a radio to establish communication with stylus  38 , such as with a BLUETOOTH protocol advertisement. At step  92 , stylus  38  receives the radio communication and responds to information handling system  10 . At step  94 , the portable information handling system determines a distance to the stylus, such as with High Accuracy Distance Measurement (HADM) or an analysis of a Return Signal Strength Indication (RSSI) and sends the distance to stylus  38  as a command to vibrate as a location aid to an end user. In an alternative embodiment, stylus  38  may perform its own determination of distance to the information handling system, such as in response to a command to vibrate. At step  96 , stylus  38  receives the command and initiates vibration with the haptic film with a vibration frequency and amplitude set based upon the distance between the stylus and information handling system. For example, when the distance is less than a meter, the stylus may vibrate at a relatively low frequency and amplitude yet generate sufficient sound to be heard by an end user, thereby reducing power consumption. If the distance is greater than a meter, the stylus vibrates at a higher frequency to generate a greater audible noise. As an example, a high frequency vibration is 300 Hz up to 20 KHz. At 20 KHz, the sound generated by the vibration enters an ultrasonic range. Specific vibrations for a stylus may be set based upon vibration response and resonant frequencies so that optimal noise is output for a given power usage. Further, vibration levels may be adjusted based upon feedback, such as a determination that a vibration results from an object placed over the stylus, where the sound produced by the vibration may be captured by an information handling system microphone or a microphone integrated in the stylus. In such an instance, the end user may be provided with a user interface message indication that the stylus is likely hidden from sight under an object. 
     Referring now to  FIG.  6   , a flow diagram depicts a process for locating a stylus with illumination based upon ambient light detection. The process starts at step  98  with portable information handling system  10  scanning for stylus  38  with radio communications and continues to step  100  with a response by the stylus to the portable information handling system. At step  102 , portable information handling system  10  initiates a determination of the ambient light conditions to determine if illumination of an LED in the stylus will be visible to an end user. In one alternative embodiment, an ambient light sensor may be included in the stylus to measure ambient light conditions at the stylus for the stylus to determine if LED illumination will provide an effective location aid. At step  104 , ambient light conditions are communicated by portable information handling system  10  to stylus  38 . At step  106 , the stylus receives the ambient light conditions and determines whether to illuminate the LED when ambient light is low or to vibrate with the haptic film when ambient light is high. In one alternative embodiment, both ambient light and vibration may be used simultaneously. 
     Referring now to  FIG.  7   , a flow diagram depicts a process for locating a stylus with vibration of a haptic film of the stylus detected by a microphone of the information handling system. In the example embodiment, the process starts at step  108  with portable information handling system  10  scanning for stylus  38  with a radio, such as BLUETOOTH advertisement. In an alternative embodiment, portable information handling system  10  may scan by playing an ultrasonic sound from a speaker. At step  110 , the stylus receives the scan request and replies with an ultrasonic vibration of 20 KHz or greater to generate the ultrasound noise. At step  112 , a microphone on the portable information handling system detects the ultrasound noise and applies the ultrasound noise to determine a direction and distance to the stylus. Using ultrasound avoids audible disruption to the end user and is detectable by ultrasound time of flight user presence detection devices found on some information handling systems. For instance, this approach allows an information handling system to track stylus location when the stylus is not in active use and thereby store a history of known positions. 
     Referring now to  FIG.  8   , a flow diagram depicts a process for locating a stylus with ultrasonic sound detected at a microphone of the stylus and an information handling system. The process starts at step  114  with a locator device, such as portable information handling system  10 , sending and ultrasonic message through a speaker with a timestamp. For example, the ultrasonic sound is emitted with long and short sounds to indicate zero and one or with a first frequency to indicate zero and a second frequency to indicate one. Alternatively, a time stamp may be passed by a wireless network where available, such as BLUETOOTH or WiFi. For instance, a radio GPIO may be used to initiate playing of the ultrasonic sound so that radio transmissions provide a time reference. At step  116 , the stylus receives the ultrasonic sound and timestamp with a microphone included in the stylus. At step  118 , the stylus haptic film vibrates to generate an ultrasonic sound with a timestamp, such as with the same protocol as used by portable information handling system  10 . At step  120  the stylus determines a time of flight for the ultrasonic sound to reach the information handling system by taking the difference of the timestamp for when the message was sent and the time for when the message was received. At step  122  the stylus uses the haptic film to generate an ultrasound message with the time of flight and sends the message to the information handling system. At step  124 , the information handling system receives the message with the time of flight and with the stylus haptic film timestamp. At step  126  the information handling system determines a distance between itself and the stylus by determining a round trip time of flight for the ultrasonic sound between the stylus and information handling system. The distance is then determined by computing from the speed of sound. Although the example embodiment determines time of flight from two way ultrasound communication, in one embodiment a single time of flight may be used. For instance, a BLUETOOTH command may be used to initiate a single ultrasonic sound communication that is used to determine distance. Once a distance is determined between the information handling system and stylus, that distance may be used to select a haptic film vibration frequency that will be sufficient for an end user to notice. 
     Although the present invention has been described in detail, it should be understood that various changes, substitutions and alterations can be made hereto without departing from the spirit and scope of the invention as defined by the appended claims.