Information handling system self-cleaning stylus

An information handling system stylus self-cleans a magnet garage arrangement with a garage variable magnet having a first magnetic attraction when the stylus is proximate and information handling system garage and a second magnetic attraction when the stylus is distal the information handling system garage. The second magnetic attraction has a reduced attractive force at the stylus housing outer surface to discourage attraction of contaminants that might scratch or otherwise damage the housing.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates in general to the field of portable information handling systems, and more particularly to an information handling system self-cleaning stylus.

Description of the Related Art

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.

For many end users, information handling systems have replaced paper for accepting handwritten notes. Stylus devices are often used to help end user interactions writing on an information handling system, both for note taking and drawing. A stylus has the shape of a pen and terminates with a writing tip that offers the end user precise placement at which inputs are made at a touchscreen display. In some instances, the writing tip as an active end that is better detected by a capacitive touchscreen to help with input precision. The stylus will also have active communication with the information handling system, such as by BLUETOOTH, to help control the active tip and support end user interactions with the stylus when active. Typically the stylus accepts a charge from the information handling system for a battery that supports power use of the writing tip, radio and a processing resource. In addition, the stylus will typically “garage” at the information handling system to store the stylus between uses and also align the stylus with charging contacts.

One common technique to garage a stylus is to have opposite pole magnets in the stylus and information handling system attracts the stylus to the side of the housing of the information handling system. To prevent the stylus from falling away, the magnets tend to have a significant magnetic attraction. One difficulty with this type of garage arrangement is that the magnets on the information handling system and stylus can attract particles that contaminate the contact location between the stylus and information handling system housing. In some instances, these contaminants can cause damage at the contact location, such as scratching, that can detract from the appearance of the information handling system and stylus.

SUMMARY OF THE INVENTION

Therefore, a need has arisen for a system and method which self-cleans contaminants at a garage contact location.

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 for magnetically coupling a device to an information handling system housing. Magnetic attraction at an outer surface of a device, such as a stylus, is increased when magnetically coupling to a garage, such as an information handling system housing, and decreased when not garaged so that the device self-cleans contaminants otherwise magnetically attracted to the device housing.

More specifically, a portable information handling system processes information with processing components disposed inside a portable housing, such as processor that processes information by executing instructions and a memory that stores the instructions and information. A garage magnet located at a side surface of the information handling system magnetically couples a stylus to the housing by opposite pole attraction to a garage variable magnet disposed in the stylus. The garage variable magnet has a first magnetic attraction when garaged at the information handling system and a second magnetic attraction of substantially less than the first magnetic attraction when distal the garage magnet. In one embodiment, the garage variable magnet moves within a channel in the stylus housing interior between a first position at the stylus housing exterior side that increases magnetic attraction to the garage and a second position at the stylus housing interior that decreases magnetic attraction to self-clean the stylus housing exterior. In another embodiment, the garage variable magnet is an electropermanent magnet that has an on state when garaged and an off state when self-cleaning the stylus housing exterior.

The present invention provides a number of important technical advantages. One example of an important technical advantage is that a stylus or other device that is magnetically garaged has the magnetic attraction selectively reduced when not garaged so that contaminants at the stylus housing exterior are released. Reduced contaminants at the stylus housing exterior reduces the risk of scratches or other damage happening at the garage location, such as an information handling system housing, so that the aesthetic appearance of the information handling system housing has reduced risk of damage.

DETAILED DESCRIPTION

Referring now toFIG.1, a block diagram depicts an exploded view of a portable information handling system10configured to garage a self-cleaning stylus28. In the example embodiment, portable information handling system10has a tablet configuration with a planar housing12that supports processing components covered by a touchscreen display26. A central processing unit (CPU)14disposed in the housing processes information by executing instructions in cooperation with a random access memory (RAM)16that stores the instructions and information. A solid state drive (SSD)18has non-transient storage, such as flash memory, that stores information and instructions during system power down. An embedded controller20manages physical operations at the information handling system, such as application of power and interactions with input/output (I/O) devices. As an example, SSD18stores an operating system and applications in persistent storage that embedded controller20retrieves at system power up to execute on CPU14. Although the example embodiment depicts a tablet format, in alternative embodiments a convertible system may be used that includes a keyboard and touchpad in housing12.

During operations, a graphics processing unit (GPU)22processes the information to define visual images for presentation at touchscreen display26, such as by generating pixel values to define colors of pixels of the touchscreen display that present a composite visual image. A wireless network interface controller (WNIC)24supports wireless communication with external devices, such as through a wireless local area network (WNIC) and a wireless personal area network (WPAN) like Bluetooth. A stylus28has a writing tip32extending from one end of a stylus housing30to write as inputs on touchscreen display26. For example, touchscreen display26includes a capacitive touch detection surface that accepts touch inputs for communication through embedded controller20to CPU14as inputs to the operating system or an application. Stylus inputs may include handwritten notes or drawings made on the touchscreen display that the operating system and applications present as visual images through GPU22. During stylus interactions, WNIC24communicates with stylus28to coordinate stylus inputs by adjusting writing tip settings for active touch detection and other types of inputs.

When stylus28is not in use, an end user can garage the stylus by attachment to housing12through magnetic attraction. A garage magnet36couples to the interior of housing12to magnetically couple stylus housing30against housing12by attraction to a garage variable magnet34coupled in the interior of stylus housing30. In the example embodiment, when garage variable magnet34couples to garage magnet36, electrical charging contacts38align to transfer power from information handling system10to stylus28. One difficulty with the use of magnets to garage stylus28to information handling system10is that the magnets tend to attract contaminants that include any micro ferromagnetic material. The contaminants can cause damage to the housing12and also the stylus housing30as hard micro grit scratches against polished or painted metal and plastic. To address this problem, garage variable magnet34decreases the amount of magnetic attraction at the outer surface of stylus housing30when stylus28is not garaged so that contaminants gathered during garaging self-clean by dropping away when the magnetic attraction decreases and additional contaminants are not attracted when the stylus is not garaged. In addition, garage magnet36may also decrease the magnetic attraction at housing12when the stylus is not garaged to also self-clean and reduce accumulation of contaminants when the stylus is not garaged.

In one embodiment, garage variable magnet34has an automated mechanical adjustment of magnetic attraction at the stylus housing by withdrawing the magnet to an interior position so that the distance between the magnet and stylus housing exterior is increased. The mechanical adjustment may use a ferromagnetic piece of material in the interior to attract the magnet to an interior position when not garaged yet release the stylus magnet when proximate the garage magnet of the information handling system. Alternatively, other interior biasing devices may be used, such as a spring that pushes the magnet to an interior position until proximity with garage magnet36pulls the stylus magnet to a position close to the housing outer surface. A similar configuration may be used for garage magnet36so long as the magnetic attraction when the opposing magnets are retracted to the interior position is sufficient to overcome the interior biasing force. As an alternative, an electropermanent magnet may be used as the garage variable magnet34and garage magnet36. Electropermanent magnets have a pair of magnets with one of the magnets having a coil that accepts a current to generate a magnet field. When the current flows in one direction it sets the direction of the magnet pole in a first direction, and when the current flows in an opposite direction it sets the direction of the magnet pole in an opposite direction. The effect is that the electropermanent magnet turns the magnetic field on and off by having like poles aligned and opposite poles aligned. When stylus28is not garaged, garage variable magnet34is turned off to self-clean contaminants. When stylus28is garaged, garage variable magnet34is turned on to support magnetic coupling to garage magnet36. A command to turn on garage variable magnet may be initiated locally with logic on stylus28, such as by detection of contact by charging contacts38, or may be initiated from information handling system10and communicated through a wireless command. In various embodiments, garage magnet36may also have variable magnetic attraction by an electropermanent magnet. Further, the electropermanent magnet may be used on information handling system10to cooperate with a mechanical variable magnet on stylus28and vice versa.

Referring now toFIG.2, a block diagram depicts a system to magnetically couple a self-cleaning stylus. In the example embodiment, information handling system10embedded controller20includes a non-transient memory that stores garage magnet module42instructions to manage stylus garaging and self-cleaning. Stylus28includes a processing resource44, such as microcontroller unit (MCU) that includes non-transient memory storing garage variable magnet module46instructions. Each of information handling system10and stylus28includes a WNIC24with a BLE module40that coordinates wireless communication, such as through Bluetooth. In the example embodiment, garage magnet36is an electropermanent magnet that is turned on when garaging stylus28and turned off when not garaging stylus28, with the magnet on and off states controlled by a GPIO of embedded controller20and instructions of garage magnet module42. For example, when stylus28is in use garage magnet is placed in an off state to self-clean the garage area of the housing. As another example, when information handling system10transitions to an off state, garage magnet is turned on to support garaging of stylus28. Wireless communication through WNIC24allows garage magnet module42to coordinate the garage magnet state with the garage variable magnet on and off states. In another alternative embodiment, garage magnet36and garage variable magnet34are turned off when electrical contacts of the information handling system and stylus are not touching and turned on when the electrical contacts are touching. In another embodiment, a button on the information handling system and stylus accepts a manual input by a press of an end user to turn the magnetic attraction on. In other embodiments, garage magnet module42and garage variable magnet module46may use other indicators to turn the magnets on and off, and may use periodic off states when not garaged to self-clean while leaving the magnets on for the majority of time to be ready to garage the magnets.

Referring now toFIG.3, a sectional side view depicts a self-cleaning stylus28configured to reduce magnetic attraction at the stylus housing30when not garaged at an information handling system housing. In the example embodiment, the amount of magnetic attraction at stylus housing30outer surface is managed by moving magnet34mechanically close and distal stylus housing30outer surface. Magnet34slides to stylus housing interior and exterior in a magnet channel54with an interior position bias supplied by a ferromagnetic material50at the inner side of magnet channel54. When distal the information handling system garage magnet, ferromagnetic material50attracts garage variable magnet34to an interior position. When placed proximate the garage magnet of the information handling system, the garage magnet attracts garage variable magnet34toward the stylus housing exterior to increase the magnetic attraction for garaging. In one example embodiment, with a garage housing thickness of 0.7 mm and movement in magnet channel54of 0.8 to 1 mm, the magnetic attraction is decreased with the interior position by a substantial amount, such as to 15% or less of the magnetic attraction at the exterior position. A leaf spring56helps to bias garage variable magnet34towards the exterior position when the garage magnet provides magnetic attraction. A switch58extends up from a printed circuit board to have an up position when the magnet is at the exterior position and to have a depressed position when magnet is in an interior position. Switch58interfaces with a printed circuit board52and processing resource44that detects the stylus garage state based upon the position of switch58.