Patent Application
20140168175
Stylus pointing devices enable information to be input to a host electronic device, such as a smart-phone or a tablet computer. When the tip of a stylus is placed in close proximity to a sensing display surface of the host device, the position of the tip may be determined by the host by a variety of methods, including the effect of the stylus on the electrical properties of the tablet (i.e., via electromagnetic induction, changes in electrical resistance, electrical capacitance, and the like); the optical properties of the tablet; or by ultrasonic positioning.
Various attempts have been made to make writing on a display of an electronic device feel more like writing with a pen on paper. In particular, when writing with a pen, there is friction between the pen and paper that is sensed by the user. This may be contrasted with writing with a stylus on the display of an electronic device where there is very little friction sensed by the user, especially when the tip of the stylus is a ball-point tip that enables the user to also write on paper. The presence of friction provides feedback to the user that facilitates better control of the pen or stylus by the user.
One attempt to introduce friction replaces the tip of the stylus with a dedicated tip such as hard plastic and increases the friction between the tip and the surface of the screen. A further attempt coats the surface of the screen with a special layer having known friction properties.
A stylus may be employed to control a virtual drawing tool such as pen, pencil, paint brush, chalk or air brush, for example, as well as other virtual tools, such as erasers. Physical drawing tools that correspond to these virtual drawing tools may each have different friction properties that cannot be modeled using a screen coating or a single modified stylus tip.
It would therefore be useful for a stylus and host electronic device to mimic the physical characteristics of physical drawing tools.
Exemplary embodiments of the present disclosure will be described below with reference to the included drawings such that like reference numerals refer to like elements and in which:
For simplicity and clarity of illustration, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. Numerous details are set forth to provide an understanding of the illustrative embodiments described herein. The embodiments may be practiced without these details. In other instances, well-known methods, procedures, and components have not been described in detail to avoid obscuring the disclosed embodiments. The description is not to be considered as limited to the scope of the embodiments shown and described herein.
One aspect of the present disclosure relates to an electronic device, such as smart-phone or tablet computer for example, configured to produce a force on a magnetic tip of a stylus. The electronic device includes a drawing surface and a number of magnetic field generators that produce a magnetic field in proximity to the drawing surface. The magnetic field generators may be electric coils embedded in the drawing surface, for example. Operational logic, such as a processor, controls the magnetic field produced by the magnetic field generators in response to the location, motion, orientation and/or contact force of the stylus. The drawing surface may be integrated with a display of the electronic device.
The magnetic field acts on a magnetic element in the tip of the stylus to produce a force on the tip. This force may have a component in the plane of the drawings surface that can be controlled to simulate friction between the stylus and the drawing surface, for example. The force may have a component perpendicular to the plane of the drawing surface that may be employed to simulate undulations or unevenness of the drawing surface or to provide feedback to a user.
The stylus has a tip end for interacting with the drawing surface of the host electronic device. A magnetic element, such as permanent magnet or electromagnet, is located at the tip end of the stylus.
The stylus may also include an energy harvester, such as a magnet that is driven by the magnetic field of the host electronic device to move within an electric coil.
The host electronic device may be controlled by a program of computer-executable instructions. These instructions may be stored on a non-transitory computer-readable medium. When executed, the processor controls the magnetic field generators to produce a magnetic field in proximity to a drawing surface in response to a sensed location of a stylus and/or sensed motion of the stylus. The magnetic field acts on a magnetic tip of the stylus and results in a force on a magnetic tip of the stylus. The force on the magnetic tip of the stylus may be controlled to have a component parallel with the drawing surface to enable simulation of a friction force on the stylus. Also the force on the magnetic tip of the stylus may be controlled to have a component perpendicular to the drawing surface to enable simulation of surface height variation or to provide feedback to a user.
The computer-executable instructions may also provide a computer drawing application having a number of virtual drawing tools such as a pen, pencil, paint brush, chalk or air brush, for example, as well as other tools, such as erasers. The corresponding physical drawing tools have different friction properties. The processor may control magnetic field generators to produce a force on the tip of the stylus that simulates properties, such as friction, of the physical drawing tool corresponding to a selected virtual drawing tool.
Accordingly, friction is simulated using the magnetic field interaction between a stylus containing a magnetic element such as a ferrous element, a permanent magnet or an electromagnet. The magnetic field may be generated by a set of controllable coils located under the screen of the host electronic device. Since the active stylus and the coils are magnetically coupled, driving the coils dependent upon the position, motion, and/or orientation of the stylus generates a force feedback that is felt by the user. The force feedback may be selected according to which virtual drawing tool is selected (pen, paint brush, carioca pens, etc), even when the stylus is close to but not touching the drawing surface (i.e. in a hover mode).
For example, when using an emulated-paint brush, the force sensed in the stylus changes according to speed, tilt angle, type of paint brush selected and paint brushing on wet paint (a physical paint brush advances more slowly in the respective area). When using an emulated-pen, the force depends on the speed and if crossing a previous trace (which feels like a dent). The magnetic field is controlled in such a way that the resulting interaction with the stylus is similar to using a physical paint brush, pen or and other utensils.
A user's experience can be improved still further when the hover distance is known, with smaller distances to the screen resulting in more force applied to the stylus when a paint brush drawing tool is selected.
In one illustrative embodiment, when a user selects a paint brush from the virtual tool box, the host displays the paint brush on the screen as it would have been viewed by the user in the case of using the paint brush on the paper. The closer the tip of the stylus is to the screen, the bigger the paint brush appears to the user on the display. The displayed paint brush is rendered in response to the direction in which the stylus is tilted.
In a further embodiment of the disclosure, a permanent magnet inside the tip of the stylus is configured to allow movement inside a coil. The permanent magnetic may be attached to the body of the stylus with springs, such as coil springs, for example. As a user moves the stylus across the drawing surface or screen, motion of the permanent magnetic is produced by interaction with the magnetic field of the host electronic device. This motion generates a current in the stylus coil that can be harvested to provide power to the stylus. The harvested energy results from the stylus movement (made by the user) and from the interaction with the coil array in the host side.
In a still further embodiment, the coils of the host electronic device may be employed to generate a magnetic field and to sense the presence of the stylus. In this embodiment, the coils act as both sensors and generators at the same time. For example, the coils may sense high frequency (KHz range) electromagnetic fields at the same time as generating low frequency (Hz range) polarized fields to simulate a resistance force on the stylus.
In yet another exemplary embodiment, the host electronic device may control the force on the stylus to transfer information to the user. This may be useful, for example, for visually impaired users. The stylus can indicate direction, form characters on the screen (numbers/letters), etc.
In a still further embodiment, the host electronic device is programmed to provide feedback to the user, through the stylus, when moving over the icons displayed in a graphical user interface or a menu, when moving or dragging icons, or when playing interactive games. For example, when dragging an icon (by pressing the “grabbing button” on the stylus, for example), a virtual disconnection from the screen may be simulated by breaking the magnetic connection between the stylus and the screen once the active stylus pulls the icon from its original place. This mimics a physical separation. Further, when the icon is dropped in the desired location (such as a Recycle Bin, other folder or new desktop position) the active stylus may interact with the surrounding icons just before the icon is released. Once the icon is released (by releasing the “grabbing button”, for example) the active stylus may be repelled for a very short period of time to indicate that the icon has been dropped.
An exemplary embodiment in accordance with various aspects of the present disclosure is shown in
Two or more magnetic field generators 106 may be employed and may be configured in an array pattern, as depicted in
In addition to generating the magnetic field, the generators 106 may also be operated as sensors to sense a magnetic field generated by the stylus 102 and thereby determine the location of the stylus with respect to the drawing surface 108.
In the illustrative embodiment depicted, the tip of the stylus 102 is in contact with the surface of a drawing surface 108 on an electronic device. The drawing surface 108 may be integrated with a display screen. Two magnetic filed generators, 106 and 106′, are located in proximity to the drawing surface 108 and are operable to produce a magnetic field. As shown, the magnetic field generators 106 and 106′ are electromagnets. The electric currents to the magnetic field generators are controlled such the electromagnet 106 is polarized with its south pole closest to the drawing surface 108, while the electromagnet 106′ is polarized with its north pole closest to the drawing surface 108. Thus, the magnetic tip 112 of the stylus is attracted to the electromagnet 106 but repelled by the electromagnet 106′. This results in a force being applied to the magnetic tip 112 of the stylus 102. This force may be controlled by a processor in response to a sensed stylus position. For example, if the stylus is moving from left to right and passes electromagnet 106′, the polarity of the electromagnet 106′ may be reversed so that the force on the stylus is maintained opposite to the direction of motion of the stylus.
In an exemplary embodiment, the strengths and polarities of the electromagnet field generators are controlled such the force on the stylus is opposed the motion of the stylus and is proportional to the velocity of the stylus so as to simulate a friction force.
In a further embodiment, the ferrous core 302 is a permanent magnetic supported in the body of the stylus 102 by spring elements 304 (depicted as coil springs here, although other types of springs may be employed). When the stylus tip is above electromagnet 106, the permanent magnet 302 is attracted towards the drawing surface 108 and the permanent magnet moves axially in the stylus towards the drawing surface 108. When the stylus tip is above electromagnet 106′, the permanent magnet 302 is repelled from the drawing surface 108 and the permanent magnet moves axially in the stylus away from the drawing surface 108. If the electromagnetic field generators have alternating polarities, either spatially or temporally, or both, the permanent magnet 302 oscillates and induces a current in the coil 300. This current may be used to drive an energy harvesting circuit. Power from the energy harvesting circuit may be used to power the stylus.
The frequency of the temporally alternating polarity of the electromagnets may be selected to coincide with a mechanical resonance frequency of the movable magnet on the spring elements.
As discussed above, the stylus 102 has a magnetic tip 112, such as a ferrous element, an electromagnet or a permanent magnet. In this embodiment, the magnetic tip 112 is controlled by control circuit 202 of the stylus. In particular, the control circuit may be employed to switch an electric current to the magnetic field generator 112 or to harvest energy from a moving element of the tip. The control circuit also includes a power supply 204, such as a battery, and an energy harvester 206 that harvests energy from a moving magnet in the magnetic tip 112. The power supply 204 may be a rechargeable battery that is recharged using harvested energy. Sensors 208 may include a tip force sensor, a tilt sensor, an accelerometer, and/or a gyroscope for example. Signals from the one or more sensors 208 are passed to a communication module 210 and may be communicated to a corresponding communication circuit 410 of the host electronic device 110 over a wireless link 412. The received sensor signals may be used by the host electronic device 110 to determine the drive signals for the magnetic field generators 408. Additionally, the drive signals are dependent upon the location of the stylus, as sensed by a stylus locator 414.
The drive signals 516 may be dependent upon graphical content displayed on a screen of the host electronic device. For example, a force may be generated to indicate the boundary of a displayed object, such as an icon, menu item, or graphical item. In another illustrative example, the stylus tip may be attracted to or repelled from displayed items.
The drive signals 516 may also be dependent upon auxiliary content 514. In an exemplary embodiment, the information may be communicated to the user via the stylus. For example, a stylus vibration may be generated to indicate an event alert.
It will be appreciated that any module or component disclosed herein that executes instructions may include or otherwise have access to non-transient and tangible computer readable media such as storage media, computer storage media, or data storage devices (removable or non-removable) such as, for example, magnetic disks, optical disks, or tape data storage. Computer storage media may include volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer readable instructions, data structures, program modules, or other data. Examples of computer storage media include RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by an application, module, or both. Any such computer storage media may be part of the server, any component of or related to the network, backend, etc., or accessible or connectable thereto. Any application or module herein described may be implemented using computer readable/executable instructions that may be stored or otherwise held by such computer readable media.
The implementations of the present disclosure described above are intended to be merely exemplary. It will be appreciated by those of skill in the art that alterations, modifications and variations to the illustrative embodiments disclosed herein may be made without departing from the scope of the present disclosure. Moreover, selected features from one or more of the above-described embodiments may be combined to create alternative embodiments not explicitly shown and described herein.
The present disclosure may be embodied in other specific forms without departing from its spirit or essential characteristics. The described exemplary embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the disclosure is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
