Tactile Interaction via Magnetism

Abstract

A touch screen device, a touch screen stylus, and a method of providing haptic feedback to a user of a touch screen device. The method includes the steps of: identifying a relative position of a tip of the touch screen stylus with respect to a sensing surface of the touch screen device; asserting a haptic force signal that changes in response to the relative position; and passing a controlled variable current through an electromagnetic circuit to apply a magnetic force between the touch screen device and the touch screen stylus, wherein the current changes depending on the haptic force signal.

Description

[0001] Background

[0002] Touchscreens are prior art user interface (UI) components common to various types of electronic devices. For example, touchscreens can use resistive, capacitive, or optical touch sensing to reliably track the touch of one or more fingers from a user or from a touchscreen stylus held in the user's hand. To provide a more immersive experience, a touchscreen display device or stylus can provide visual or auditory feedback to the user as the touch point moves across the sensing surface of the device.

[0003] Overview

[0004] One aspect of the present disclosure relates to a touchscreen device including a position sensor, an electromagnetic circuit, and a drive circuit. The position sensor is configured to sense the relative position of a magnetically-attractable tip of a touchscreen stylus relative to the sensing surface of the touchscreen device. The electromagnetic circuit carries a current and forms a magnetic force proportional to the current to attract the magnetized tip to the sensing surface. The drive circuit is configured to receive a haptic force signal and change the magnetic force by changing the current depending on the haptic force signal, which in turn changes depending on the relative position.

[0005] Another aspect of the present disclosure relates to a touchscreen stylus for a magnetically-attractable touchscreen device. The touchscreen stylus includes an electromagnetic circuit and a drive circuit. The electromagnetic circuit disposed at the tip of the touchscreen stylus carries a current and forms a magnetic force proportional to the current to attract the touchscreen device to the tip. The drive circuit is configured to receive a haptic force signal and change the magnetic force by changing the current depending on the haptic force signal, which in turn changes depending on the relative position of the tip of the touchscreen stylus relative to the sensing surface of the touchscreen device.

[0006] Another aspect of the present disclosure relates to a method of providing haptic feedback to a user of a touchscreen device. The method includes the steps of: identifying the relative position of a tip of a touchscreen stylus relative to the sensing surface of the touchscreen device; asserting a haptic force signal that changes in response to the relative position; and passing a controlled variable current through an electromagnetic circuit to apply a magnetic force between the touchscreen device and the touchscreen stylus, wherein the current changes depending on the haptic force signal.

[0007] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Additionally, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure. Brief Description of the Drawings

[0009] Figure 1Shows aspects of an example touchscreen device.

[0010] Figure 2 Shows aspects of the capacitive touchscreen of an example touchscreen device.

[0011] Figure 3 Shows aspects of an example touchscreen system including a touchscreen device and a touchscreen stylus.

[0012] Figure 4 and 5 Shows aspects of another example touchscreen system including a touchscreen device and a touchscreen stylus.

[0013] Figure 6A and 6B Shows aspects of another example touchscreen device.

[0014] Figure 7 and 8 Shows additional aspects of other example touchscreen devices.

[0015] Figure 9 Illustrates an example method of providing haptic feedback to a user of a touchscreen device.

[0016] Detailed description

[0017] Although a touchscreen device or stylus can provide visual or auditory feedback to a user as the touch point moves across the sensing surface of the device, a more immersive experience can be provided in a system configured for haptic feedback. Specifically, haptic feedback can be used to provide sensations coordinated with any changing variables, including the movement of the user's touch point across the sensing surface. Some implementations of this idea employ a touchscreen stylus configured to vibrate depending on the position of the touch point relative to the sensing surface. The figure of merit of any device providing haptic feedback is the degree to which the user's experience of operating the device resembles a similar real-world experience. However, the position-dependent vibration of a touchscreen stylus in a user's hand is very dissimilar to the sensation of moving a real-world object across real-world terrain. For example, some parts of real-world terrain (e.g., a frozen pond) may offer little resistance to the movement of an object, while other parts (e.g., sand, hills, or fences) may offer increased resistance. Superficially, making a touchscreen stylus vibrate depending on touch point position does not convincingly simulate variable resistance to motion.

[0018] In contrast, the touchscreen system described herein is configured to vary the magnetic force applied between the sensing surface of the touchscreen and a touchscreen stylus held in a user's hand. In scenarios where the tip of the touchscreen stylus is in physical contact with the sensing surface, the varied magnetic force imparts a varied frictional force between the tip and the surface, which not only mimics but actually results in a variable resistance to movement. Operationally, the systems described herein can be used to model a heterogeneous terrain on the sensing surface of the touchscreen that a user can navigate via the touchscreen stylus. The terrain can include some regions where the tip moves easily across the sensing surface, as well as other regions where movement is more difficult or restricted. The ease with which the touchscreen stylus moves across any region of the touchscreen surface can additionally or alternatively be varied according to time or any other suitable parameter. These and other features are described in more detail below.

[0019] The present disclosure will now be presented by way of example and with reference to the drawings listed above. Components, process steps, and other elements that may be substantially the same in one or more of the drawings are coordinately identified and described with a minimum of repetition. However, it should be noted that the elements so identified may also differ to some extent. It should further be noted that the drawings are schematic and generally not drawn to scale. Instead, the various drawing scales, aspect ratios, and numbers of components shown in the drawings may be deliberately distorted to make it easier to see certain features or relationships.

[0020] Figure 1 Aspects of an example touchscreen device 10A that includes a touchscreen 12R are shown. Touchscreen device 10A is part of a touchscreen system that may also include a touchscreen stylus (see below). In the illustrated example, the touchscreen device is a tablet computer system: it includes a display 14R and an integrated computer system 16A. In other examples, the touchscreen device may take the form of a smart phone, a laptop computer system, an all-in-one computer system, or a computer system monitor. Since neither the computer system nor the display is strictly necessary, in still other examples, the touchscreen device may take the form of a touchpad, a stand-alone touch input system, or virtually any device configured to sense touch. In examples that include an integrated or peripheral computer system 16A, the computer system may include at least one processor 18A and an associated computer-memory system 20A. The computer-memory system may hold instructions that cause the processor to perform any of the methods disclosed herein. In some examples, the display 14R of touchscreen device 10A may be a liquid crystal display (LCD). In other examples, the display may be a light-emitting diode (LED) display, an organic LED (OLED) display, a projection display, a scanned beam display, or virtually any other type of display.

[0021] The touch screen 12R of the touch screen device 10A is configured to sense at least one touch point 22 affected by a user. An example touch point is a contact point between the user's fingertip 24 and the sensing surface 26 of the touch screen. Figure 2 Additional aspects of the touch screen 12R are shown in one non - limiting example. Figure 2 The touch screen is a capacitive touch screen. A position sensor 28 is disposed below the sensing surface of the touch screen, and the position sensor 28 is configured to sense the relative position of the touch point 22 relative to the sensing surface. The position sensor may take the form of a transparent conductive film structure. The outer electrically conductive layer of the film structure may be etched to form a series of row (i.e., drive) electrodes 30 and a series of column (i.e., sense) electrodes 32. The touch screen contemplated herein may include any number N of row electrodes and any number M of column electrodes. Although it is customary to align the row electrodes horizontally and the column electrodes vertically, this is by no means necessary since the terms "row" and "column" may be interchanged anywhere in this specification. The row and column electrodes of the touch screen 12R are addressed by touch screen logic 34. The touch screen logic is configured to sense user interactions on the sensing surface 26, including the coordinates X, Y directly behind the user contact point of a finger or stylus on the sensing surface. To this end, the touch screen logic includes row driver logic 36 and column sense logic 38, and may include other components as described herein.

[0022] The column sense logic 38 includes M column amplifiers each coupled to a corresponding column electrode 32. The row driver logic 36 includes a row counter 40 in the form of an N - bit shift register, the output of which drives each of the N row electrodes 30. The row counter is timed by a row driver clock 42. The row counter includes a blanking input that temporarily forces all output values to zero independent of the stored value. One or more rows may be driven by filling each output of the row counter to be driven with a 1 and filling the other outputs of the row counter with a 0, and then toggling the blanking signal with the desired modulation from a modulation clock 44. In the illustrated example, the output voltage may take only two values corresponding to a 1 or 0 stored in each bit of the row counter. In other examples, for instance, the output voltage may take a wider range of values to reduce the harmonic content of the output waveform or reduce the radiation emissions.

[0023] The row driver logic 36 applies an excitation pulse sequence to each row electrode 30. During periods in which the sensing surface 26 is not touched, none of the column amplifiers latch a supra-threshold output. However, when the user places a fingertip on the sensing surface, the fingertip capacitively couples one or more row electrodes 30 that intersect the touch point 22 to one or more column electrodes 32 that also intersect the touch point. The capacitive coupling induces a supra-threshold signal in the column amplifiers associated with the column electrodes beneath (i.e., adjacent to) the touch point. The column sensing logic 38 returns the digital value of the column providing the largest received signal as the X coordinate of the touch point. The touch screen logic 34 also determines which row is being excited when the largest signal is received and returns the digital value of that row as the Y coordinate of the touch point.

[0024] The column sensing logic 38 can also return a Z coordinate that varies depending on the strength of the signals received at coordinates X, Y. Accordingly, the touch screen logic 34 can distinguish a firm touch associated with a strong signal from a light touch associated with a weaker signal and a hover associated with a still weaker but detectable signal.

[0025] Briefly returning to Figure 1 , a touch screen stylus 46R can be used instead of the user's fingertip to perform touch input on the touch screen device 10A. Accordingly, the position sensor 28 of the touch screen device can be configured to sense the relative position of the tip 48 of the touch screen stylus with respect to the sensing surface 26 of the touch screen device. Like the user's fingertip, the tip of a passive touch screen stylus includes a high dielectric constant material that capacitively couples the row and column electrodes beneath the touch point. Passive touch screen styli provide better touch accuracy than fingertips and can reduce smudging of the sensing surface. Relative to passive styli, active touch screen styli provide even higher touch accuracy in addition to tracking touch points faster and more accurately (see below). Although passive or active touch screen styli typically take the form of an elongated cylinder or pen, this aspect is not strictly necessary. Figure 1 A replacement shaped touch screen input device 46S that can be used on a large format touch screen device 10S having a display 14S and a touch screen 12S is shown. It will be noted that touch screen input devices of various shapes and sizes are envisioned herein, and all references to styli apply equally to other touch screen input devices.

[0026] Figure 3is a schematic representation of a touchscreen device 10A showing a series of stacked layers including a touchscreen 12R and a display 14R. The backlight of the display is from a light guide plate (LGP) 50 and illuminates a polarizer 52 via a series of reflectors, diffusers, and / or prism films. The polarizer 52 selects light of a desired polarization state to enter a thin film transistor (TFT) glass 54. The TFT glass supports a nematic liquid crystal layer that can selectively rotate the polarization plane of light in response to an external bias applied to individual light-emitting pixel elements of the TFT glass. The light then passes through a color filter (CF) glass 56 including an array of CF elements positioned in alignment with the pixel elements of the TFT glass, and then through a second polarizer 52', where light of an undesired polarization state is blocked. The second polarizer is bonded to a position sensor 28 by a layer of optically clear adhesive (OCA), which also bonds the position sensor to a cover glass 58.

[0027] Figure 3 Also shown is an example touchscreen stylus 46A and additional features of the touchscreen device 10A that cooperate with the touchscreen stylus to provide haptic feedback to a user of the touchscreen system.

[0028] The computer system 16A of the touchscreen device 10A is configured to execute an operating system (OS) 60 and at least one application 62. During execution, the OS or the application can assert a haptic force signal 64 corresponding to a desired suction level between the sensing surface 26 of the touchscreen device and the tip 48 of the touchscreen stylus 46A. In some examples, the haptic force signal is changed by the OS or the application depending on the coordinates X, Y, and / or Z of the touch point 22 - that is, depending on the relative position of the tip of the touchscreen stylus with respect to the sensing surface. In one non-limiting example, the OS or the application can maintain a mapping of the sensing surface, where an expected value of the suction Fi is mapped to a set of coordinates (X,Y) i for each of them. This mapping can establish an analog terrain of the sensing surface. The analog terrain can include regions where F i is relatively small and the tip is easily movable, and regions where F i is relatively large and the tip has restricted movement. The value of each F i in the mapping can be changed in any suitable increment and within any suitable range. In this example, the haptic force signal 64 can be changed depending on the value of F i at the current touch point coordinates X, Y. In other examples, the OS or the application can calculate a numerical function depending on the touch point coordinates to determine the haptic force signal. In these and other examples, the haptic force signal can be changed with the Z coordinate of the touch point. For example, if the tip 48 is lifted off the surface by a distance exceeding that indicating hovering, the haptic force signal can drop to zero.

[0029] In these and other examples, the value of the haptic force signal at any, some, or all of the coordinates (X, Y, Z) can change at different execution stages of the OS 60 and / or the application 62. For example, the haptic force signal asserted when the touchscreen stylus 46A tracks a given path P on the sensing surface 26 can be set to a lower value when the path is first tracked and a higher value when the path is tracked a second time. For example, the greater friction applied during subsequent movement along the same path can be likened to the turning of a turntable or the tightening of a screw.

[0030] The touchscreen device 10A includes an electromagnetic circuit 66A that is configured to carry a current and thereby form a magnetic field extending outside the touchscreen device in proportion to the current. The electromagnetic circuit can include a coil of a conductive winding wound around a suitable core. In some examples, the core can be a hollow magnetic core. In other examples, the core can include a soft ferromagnetic material that is configured to concentrate the magnetic field in a region of the sensing surface 26. In some examples, an exotic magnetic material (such as a superparamagnetic material) can be used instead of the soft ferromagnetic material.

[0031] The drive circuit 68A is configured to receive a haptic force signal from the OS 60 or the application 62 and change the current in the electromagnetic circuit 66A depending on the haptic force signal. As Figure 3 shown, when the nib is within the range of the electromagnetic circuit, the magnetic field formed in this way can extend to the nib 48 of the touchscreen stylus 46A.

[0032] To exhibit a haptic force F in response to the magnetic field from the electromagnetic circuit 66A, the nib 48 of the touchscreen stylus 46A is magnetically attractive. Specifically, the nib can include one or more of a permanent magnet and a soft ferromagnetic material. When positioned within the magnetic field of the electromagnetic circuit 66A, the magnetic domains of the soft ferromagnetic material are temporarily aligned in a direction parallel to the magnetic field gradient. This creates a magnetic attraction force between the electromagnetic circuit and the soft ferromagnetic material that is proportional to the absolute value of the current flowing through the electromagnetic circuit. Apparently, the magnetic domains of the permanent magnet are aligned parallel to the axis of the magnet, which can be arranged parallel or anti-parallel to the magnetic field gradient from the electromagnetic circuit 66A. In an example where the magnetic domains are parallel to the magnetic field gradient, a magnetic attraction force is applied between the electromagnetic circuit and the permanent magnet. In an example where the magnetic domains are anti-parallel to the magnetic field gradient, a magnetic repulsion force is applied between the electromagnetic circuit and the permanent magnet. Generally, the sign of the magnetic field gradient formed by the electromagnetic circuit 66A is determined by the direction of the current flowing through the electromagnetic circuit. Accordingly, in an example where the nib 48 includes a permanent magnet, the drive circuit 68A of the touchscreen device 10A can be configured to reverse the direction of the current in the electromagnetic circuit to apply a magnetic attraction force or a magnetic repulsion force on the touchscreen stylus depending on the direction of the current. For example, the permanent magnet that can be used for the nib of the touchscreen stylus includes a compact neodymium magnet.

[0033] In Figure 3 In the example shown, the touchscreen device 10A includes an optional force sensor 70A that responds to the contact force of the tip 48 of the touchscreen stylus 46A on the sensing surface 26. In implementations that include an optional force sensor, the drive circuit 68A can be configured to further change the current in the electromagnetic circuit 66A depending on the output of the force sensor to apply closed-loop control to the contact force. In some examples, the force sensor can include a resistive touchscreen overlay integrated with a capacitive position sensor 28 for reducing the overall thickness of the touchscreen 12R.

[0034] Figure 4 and 5 shows aspects of another touchscreen system, but where the electromagnetic circuit is arranged in the touchscreen stylus and the touchscreen device is magnetically attachable. Figure 4 The touchscreen stylus 46B of includes an electromagnetic circuit 66B arranged at the tip 48. The electromagnetic circuit carries a current and forms a magnetic field extending outside the touchscreen stylus in proportion to the current. The magnetic field from the electromagnetic circuit 66B can extend to an area 72 of the touchscreen device 10B in which a soft ferromagnetic material is distributed or in which distributed permanent magnets are arranged. The term "distributed permanent magnet" can apply to an array of permanent magnets with mutually aligned magnetic axes or to a dispersion of a hard ferromagnetic material magnetized to form mutually aligned magnetic domains.

[0035] Turning now to Figure 5 , the drive circuit 68B of the touchscreen stylus 46B is configured to receive a haptic force signal that can originate from the touchscreen device 10B, as described above in the context of the touchscreen device 10A. The haptic force signal can be received wirelessly via a transceiver 74B, which can be a radio transceiver, an infrared transceiver, or an acoustic transceiver. The drive circuit 68B is configured to change the current in the electromagnetic circuit 66B depending on the received haptic force signal. As in the previous example, the haptic force signal can change depending on the relative position of the tip of the touchscreen stylus with respect to the sensing surface of the touchscreen device.

[0036] In an implementation where the region 72 of the touchscreen device 10B includes distributed permanent magnets, the drive circuit 68B can be configured to reverse the direction of the current in the electromagnetic circuit 66B to apply a magnetic attraction or magnetic repulsion force on the touchscreen stylus depending on the direction of the current. In some examples, the distributed permanent magnets in the region 72 can form a uniform magnetic field at the sensing surface 26 of the touchscreen device. In other examples, the magnetic field can be non-uniform at the sensing surface. In some examples where the magnetic field is non-uniform, the current in the electromagnetic circuit 66B can be adjusted based on the measured or predicted magnetic field strength at the touch point coordinates to compensate for the non-uniformity. For example, an appropriate compensation factor can be obtained by querying a look-up table stored in the computer-memory system 20A or a Hall effect sensor arranged in the nib 48.

[0037] In some examples, as Figure 5 shown, the touchscreen stylus 46B can include an optional force sensor 70B that responds to the contact force of the nib 48 on the sensing surface 26 of the touchscreen device 10B. The drive circuit 68B can be configured to further change the current depending on the output of the force sensor to apply closed-loop control to the contact force. In other examples, the closed-loop control of the current can be affected based on the output of a contact force sensor integrated in the touchscreen 12R (as in the previous example). In this configuration, the transceiver 74B can be used to communicate appropriate sensing signals between the touchscreen and the touchscreen stylus.

[0038] In this example and other examples, the touchscreen stylus 46B can be one of multiple touchscreen styluses of equivalent configurations that can be used concurrently on the same touchscreen device. In a scenario where multiple touchscreen styluses are used concurrently, the position sensor 28 can be configured to sense the relative position of the nib of each touchscreen stylus with respect to the sensing surface 26, and the drive circuit 68 can be configured to independently change the current in each of the multiple electromagnetic circuits 66 depending on the haptic force signals provided independently for each touchscreen stylus.

[0039] In Figure 4 and 5 's example, independent haptic feedback can be provided concurrently to multiple users of the same touchscreen device by means of active electromagnetic circuits arranged in each touchscreen stylus. This approach also offers an efficiency advantage because the magnetic field is only electromagnetically formed in the regions of the touchscreen system where haptic feedback is required. The following examples illustrate other configurations where similar advantages can be achieved using electromagnetic circuits arranged in the touchscreen device.

[0040] Figure 6A and 6B show aspects of an example touchscreen device 10C that includes multiple independently controlled electromagnetic regions, each with its own electromagnetic circuit 66.Figure 6A The electromagnetic circuit 66C is one of a plurality of electromagnetic circuits of the touchscreen device. Each electromagnetic circuit carries a current and forms a magnetic field that extends into a corresponding area outside the touchscreen device in proportion to the current. The drive circuit 68C is configured to independently vary the current in each of the plurality of electromagnetic circuits depending on the haptic force signal, thereby controlling the magnetic field in each of the corresponding areas. The OS or application of the touchscreen device may provide an independent haptic force signal for each electromagnetic area. In this example, the tip 48 of the touchscreen stylus 46A may include one or more of a permanent magnet and a ferromagnetic material.

[0041] The number and / or shape of the independently controlled electromagnetic areas and the corresponding electromagnetic circuits 66 of the touchscreen device 10C may vary depending on the implementation. In principle, the touchscreen device may include an electromagnetic circuit at each intersection of the row electrodes and column electrodes for the position sensors. On the other hand, as few as two electromagnetic circuits covering different areas of the sensing surface 26 can reduce the power consumption in the touchscreen device. In some implementations, adjacent electromagnetic circuits may overlap in order to maintain the magnetic field strength between adjacent independently controlled electromagnetic areas.

[0042] In the above example, each electromagnetic circuit 66 is disposed within the housing 76 of the touchscreen device behind the position sensor 28 and the display 14R. In other examples, the electromagnetic circuit may be integrated into the position sensor or the display layer of the touchscreen device. For example, in Figure 8 and 9 the example shown, the electromagnetic circuit is integrated into the excitation electrodes of the position sensor.

[0043] Figure 7 The touchscreen device 10D of includes a position sensor 28D. As in the previous example, the position sensor includes a series of row electrodes 30D and a series of column electrodes 32D. Each row electrode includes an electromagnetic circuit 66D at the intersection of that row electrode and each column electrode. The electromagnetic circuit includes a plurality of concentric windings formed on the position sensor. In an example where the position sensor is a thin film with an etched conductive outer layer, the concentric winding pattern may be etched into one or both of the outer layers. In some examples, each electromagnetic circuit may be independently controlled by an associated drive circuit. In other examples, the electromagnetic circuits of the same row may be connected in series and controlled together. As in all the illustrated examples, the number and shape of the independently controlled electromagnetic circuits should not be construed as limiting in any sense, as touchscreen devices with more or fewer independently controlled electromagnetic circuits are equivalently envisioned.

[0044] Figure 8The touchscreen device 10E includes a position sensor 28E. As in the foregoing example, the position sensor includes a series of row electrodes 30E. In this example, the electromagnetic circuit 66E includes adjacent, parallel row electrodes 30E of the position sensor that carry current in opposite directions. In the illustrated scenario, the row electrode immediately above the touch point 22 carries current from left to right, while the row electrode immediately below the touch point carries current from left to right. This current flow pattern forms a magnetic field (i.e., outside the plane of the position sensor) that is oriented perpendicular to the column electrode array in the region of the touch point 22. Although the drawings show current flowing through two row electrodes above the touch point and through two row electrodes below the touch point, the number of rows carrying current can vary depending on the implementation.

[0045] Figure 9 An example method 78 for providing haptic feedback to a user of a touchscreen device is illustrated.

[0046] At 80 of method 78, the relative position of the tip of a touchscreen stylus with respect to the sensing surface of the touchscreen device is identified. In some examples, the touch point coordinates X, Y, and / or Z can be determined by the touchscreen device and / or the touchscreen stylus, as described above and further described below.

[0047] At 82, the OS or application executing on the touchscreen device asserts a haptic force signal corresponding to a desired suction level between the sensing surface of the touchscreen device and the tip of the touchscreen stylus. In some examples, the haptic force signal can vary depending on the relative position of the tip of the touchscreen stylus with respect to the sensing surface, as described above. In some examples, the haptic force signal can be used to distinguish regions on the sensing surface where the tip of the touchscreen stylus moves easily from regions where movement is restricted or limited. For example, regions of easy, restricted, or limited movement can be defined to provide a user with context about the virtual topography of the sensing surface, to set fences that a touch point should not move beyond, or to improve accessibility for visually impaired users. In these and other examples, the haptic force signal can vary depending on the execution time or progress of the OS or application asserting the haptic force signal.

[0048] At 84, a current that is controllably varied depending on the haptic force signal passes through the electromagnetic circuit. This action applies a magnetic force between the touchscreen device and the touchscreen stylus. The magnetic force can include a suction force between the tip of the touchscreen stylus and the sensing surface of the touchscreen device. Here, the suction force can apply a frictional force between the tip of the touchscreen stylus and the sensing surface, and the frictional force can be proportional to the suction force.

[0049] In some implementations, the electromagnetic circuit through which the controlled variable current passes is the electromagnetic circuit of the touchscreen device. Here, the tip of the touchscreen stylus may include a permanent magnet or ferromagnetic material. In other implementations, the electromagnetic circuit through which the controlled variable current passes is the electromagnetic circuit of the touchscreen stylus. Here, the touchscreen device may include a permanent magnet or ferromagnetic material.

[0050] Optionally, at 86, the contact force between the tip of the touchscreen stylus and the sensing surface of the touchscreen device may be sensed. In implementations including this step, the current through the electromagnetic circuit may be adjusted in a closed-loop manner such that the contact force sensed at 86 approaches a desired setpoint value corresponding to the haptic force signal.

[0051] Optionally, at 88, in a scenario where the haptic force signal is time-modulated, the current applied at 84 may be time-modulated. The time-modulation of the applied current causes the suction and frictional forces to be similarly modulated. This effect can be used to provide a sense of surface roughness as the touchscreen stylus passes over certain regions of the sensing surface.

[0052] To more fully describe the modal range by which the touchpoint coordinates X, Y, and / or Z may be determined at 80 in the above method, reference will now be made again to Figure 5 to describe additional aspects of the active touchscreen stylus 46B.

[0053] In this figure, a detection electrode 90 is disposed at the tip 48 of the touchscreen stylus 46B. The detection electrode is operatively coupled to associated sensing logic 92 and injection logic 94. The sensing and injection logic are operatively coupled to the microprocessor 18B and may be partially embodied within the microprocessor 18B. The microprocessor 18B configured for digital signal processing (DSP) is operatively coupled to an associated computer-memory system 20B. The sensing logic 92 includes linear analog components that are configured to maintain the detection electrode 90 at a constant voltage and convert any current flowing into or out of the detection electrode 90 into a proportional current-sense voltage. The sensing logic includes an analog-to-digital (A / D) converter 96 that converts the current-sense voltage into digital data for subsequent processing.

[0054] Instead of the rows and columns of electrodes of the dielectric capacitive coupled touchscreen 12R, the sensing logic 92 of the touchscreen stylus 46B senses the arrival of the excitation pulses from the row electrode 30 under (i.e., adjacent to) the touch point and, in response, injects charge into the column electrode 32 also under the touch point. To this end, the touchscreen stylus 46B includes injection logic 94 associated with the sensing electrode 90 and configured to control the charge injection from the sensing electrode 90 to the column electrode directly under (i.e., adjacent to) the sensing electrode. The injected charge appears to the column sensing logic 38 of the touchscreen as an electrostatic pulse similar to that transferred via capacitive coupling from the column electrode 32 to the energized row electrode 30 intersecting at the touch point 22. Accordingly, in some examples, the touchscreen logic is not limited to the touchscreen device, but also extends to the microprocessor 18B of the touchscreen stylus and the computer-memory system 20B.

[0055] In some examples, the sensing logic 92 and the injection logic 94 are active during non-overlapping time windows of each touch sensing frame such that charge injection and charge sensing can be performed at the same sensing electrode 90. In this implementation, the touchscreen logic 34 energizes the series of row electrodes 30 during the time window when the sensing logic is active, but suspends the row excitation during the time window when the touchscreen stylus 46B can inject charge. This strategy provides an additional advantage as it enables the touchscreen logic 34 to distinguish between the touch points affected by the touchscreen stylus 46B and those affected by a fingertip or palm. If the column sensing logic 38 detects charge from the column electrode 32 during the charge injection time window of the touchscreen stylus 46B (when no row electrode 30 is energized), the detected touch point 22 must be the touch point of the touchscreen stylus. However, for example, if the column sensing logic detects charge during the charge sensing window of the touchscreen stylus (when the row electrode 30 is energized), the detected touch point may be the touch point of a fingertip, hand, or passive touchscreen stylus.

[0056] After active sensing, charge injection allows the touch point 22 in a very small area to be precisely located without requiring a long integration time that would increase the waiting time for touch sensing. For example, when a signal is received from the row electrode 30, the touchscreen stylus 46B can inject a charge pulse whose amplitude is proportional to the strength of the received signal. Thus, the position sensor 28 can receive the electrostatic signal from the touchscreen stylus 46B and calculate the Y coordinate, which can be the row that provides the maximum signal from the touchscreen stylus, or a function of the signals received at that row and adjacent rows. However, this approach presents various challenges. The main challenge is that the sensing logic 92 and the injection logic 94 must operate simultaneously - that is, in full-duplex mode. Various methods - for example, code division or frequency division multiple access - can be applied to eliminate strong interference from the transmission direction at the receiving direction. The position sensor may need to receive two signals simultaneously (one from the row electrode 30 and the other from the touchscreen stylus sensing electrode 90). The system can also operate in time division, but at the cost of the available integration time.

[0057] Another solution is to require the touchscreen stylus 46B to play a more active role in determining the touch point coordinates. In the illustrated example, the sensing logic 92 of the touchscreen stylus 46B includes a local row counter 98 that remains synchronized with the row counter 40 (hereinafter referred to as the remote row counter) of the touchscreen logic 34. This feature gives the touchscreen stylus and the touchscreen a shared sense of timing without being wired together.

[0058] When the sensing electrode 90 touches the sensing surface 26 of the touchscreen 12R, the sensing logic 92 receives a waveform that persists as long as the touch is maintained. The waveform obtains its maximum amplitude at the moment when the row electrode 30 directly below (i.e., adjacent to) the sensing electrode 90 is energized. The sensing logic 92 is configured to sample the waveform at each increment of the local row counter 98 and determine when the maximum amplitude is sensed. For example, this determination can be made once per frame.

[0059] Since the touchscreen stylus 46B and the touchscreen 12R have a shared timing due to the synchronized row counters, the state of the local row counter 98 at the maximum sensed amplitude directly reports the row coordinate - that is, the Y coordinate - of the touch point 22. To utilize this information, the Y coordinate must be communicated back to the touchscreen logic 34. To this end, the touchscreen stylus includes a transceiver 74B that is configured to wirelessly communicate the calculated row coordinate to the row sensing logic of the touchscreen. The present disclosure encompasses various modes of communicating data (including the Y coordinate) from the touchscreen stylus to the touchscreen.

[0060] None of the foregoing aspects of the accompanying drawings or the specification should be construed in a limiting sense, as numerous variations, extensions, and omissions are also conceivable. For example, although the touch screen 12R described above is a capacitive touch screen, the present disclosure is equally consistent with touch screens having resistive and / or optical touch sensing components. In an example where a given layer of a touch screen stack is used for the combined purposes of display, touch sensing, and / or magnetic field formation, these actions need not be performed concurrently, but may be performed in a time division multiplexed manner. For example, a user interface frame of a touch screen device may be partitioned into display, touch sensing, and magnetic field sub-frames, where appropriate signals are sent to the combined layer during each sub-frame.

[0061] In some implementations, the methods and processes described herein may be bound to the computing system of one or more computer system devices. Such methods and processes may be implemented as an operating system (OS), application or service, application programming interface (API), library, and / or other computer system program product.

[0062] Figure 1 and 5 FIG. shows a schematic representation of a computer system 16 configured to provide any and all of the computer system functionality described herein. Each computer system 16 includes a logic system 18 and a memory system 20. The computer system 16 may optionally include a display system 14, an input system 12, a communication system 74, and / or other systems not shown in the figures.

[0063] The logic system 18 includes one or more physical devices configured to execute instructions. For example, the logic system may be configured to execute instructions as part of at least one operating system (OS), application, service, and / or other program construct. The logic system may include at least one hardware processor (e.g., a microprocessor, central processor, central processing unit (CPU), and / or graphics processing unit (GPU)) configured to execute software instructions. Additionally or alternatively, the logic system may include at least one hardware or firmware device configured to execute hardware or firmware instructions. The processors of the logic system may be single-core or multi-core, and the instructions executed thereon may be configured for serial, parallel, and / or distributed processing. The individual components of the logic system may optionally be distributed among two or more separate devices, which may be located remotely and / or configured for cooperative processing.

[0064] Memory system 20 includes at least one physical device configured to temporarily and / or permanently hold computer information, such as data and instructions executable by logic system 18. When the memory system includes two or more devices, these devices may be co-located and / or located remotely. Memory system 20 may include at least one volatile, non-volatile, dynamic, static, read / write, read-only, random access, sequential access, location-addressable, file-addressable, and / or content-addressable computer system-memory system device. Memory system 20 may include at least one removable and / or built-in computer system-memory system device. When the logic system executes instructions, the state of memory system 20 may be transformed—for example, to hold different data.

[0065] Aspects of logic system 18 and memory system 20 may be integrated together into one or more hardware logic components. For example, any such hardware logic component may include at least one program and application specific integrated electromagnetic circuit (PASIC / ASIC), program and application specific standard product (PSSP / ASSP), system on a chip (SOC), or complex programmable logic device (CPLD).

[0066] Logic system 18 and memory system 20 may cooperate to instantiate one or more logical machines or engines. As used herein, the terms “machine” and “engine” each collectively refer to a combination of cooperating hardware, firmware, software, instructions, and / or any other components that provide computer system functionality. In other words, machines and engines are never abstract concepts, but always have a tangible form. A machine or engine may be instantiated by a single computer system device, or a machine or engine may include two or more sub-components instantiated by two or more different computer system devices. In some implementations, a machine or engine includes local components (e.g., software applications executed by a computer system processor) that cooperate with remote components (e.g., cloud computing services provided by a network of one or more server computer systems). The software and / or other instructions that give a particular machine or engine its functionality may optionally be saved as one or more unexecuted modules on one or more computer system-memory system devices.

[0067] When included, display system 14 may be used to present a visual representation of data held by memory system 20. In some examples, the visual representation may take the form of a graphical user interface (GUI). Display system 14 may include one or more display devices utilizing substantially any type of technology. In some implementations, the display system may include one or more virtual reality, augmented reality, or mixed reality displays.

[0068] When including the input system 12, the input system 12 may include or interface with one or more input devices. The input devices may include sensor devices or user input devices. Examples of user input devices include a keyboard, a mouse, or a touch screen.

[0069] When including the communication system 74, the communication system 74 may be configured to communicatively couple the computer system 16 with one or more other computer systems. The communication system 74 may include wired and / or wireless communication devices that are compatible with one or more different communication protocols. The communication system may be configured to communicate via a personal area network, a local area network, and / or a wide area network.

[0070] To further generalize, one aspect of the present disclosure relates to a touch screen device including a position sensor, an electromagnetic circuit, and a drive circuit. The position sensor is configured to sense the relative position of a magnetic tip of a touch screen stylus with respect to a sensing surface of the touch screen device. The electromagnetic circuit carries a current and forms a magnetic force proportional to the current to attract the magnetic tip to the sensing surface. The drive circuit is configured to receive a haptic force signal and change the magnetic force by changing the current depending on the haptic force signal, where the haptic force signal changes depending on the relative position.

[0071] In some implementations, the electromagnetic circuit is one of a plurality of electromagnetic circuits of a touchscreen device, each electromagnetic circuit carrying a current and forming a magnetic field extending into a corresponding area outside the touchscreen device in proportion to the current. Herein, the drive circuit is configured to independently change the current in each of the plurality of electromagnetic circuits depending on the haptic force signal, thereby controlling the magnetic field in each of the corresponding areas. In some implementations, the touchscreen stylus is one of a plurality of touchscreen styli that can be used concurrently on the touchscreen device. Herein, the position sensor is configured to sense the relative position of the tip of each touchscreen stylus with respect to the sensing surface, and the drive circuit is configured to independently change the current in each of the plurality of electromagnetic circuits depending on the haptic force signal provided independently for each touchscreen stylus. In some implementations, the electromagnetic circuit is integrated into the position sensor or the display layer of the touchscreen device. In some implementations, the position sensor includes a capacitive sensing electrode array, and the electromagnetic circuit is integrated into the excitation electrodes of the electrode array. In some implementations, the electromagnetic circuit includes a plurality of concentric windings formed at the intersections of the excitation electrodes and the sensing electrodes of the electrode array. In some implementations, the electromagnetic circuit includes parallel excitation electrodes in the electrode array that carry current in opposite directions. In some implementations, the magnetic tip includes a permanent magnet, and the drive circuit is configured to reverse the direction of the current to apply a magnetic repulsive force on the touchscreen stylus. In some implementations, the touchscreen device further includes a force sensor that responds to the contact force of the tip of the touchscreen stylus on the sensing surface, and the drive circuit is configured to further change the current depending on the output of the force sensor. In some implementations, the force sensor includes a resistive touchscreen overlay integrated with the capacitive position sensor.

[0072] Another aspect of the present disclosure relates to a touchscreen stylus for a magnetic touchscreen device. The touchscreen stylus includes an electromagnetic circuit and a drive circuit. The electromagnetic circuit disposed at the tip of the touchscreen stylus carries a current and forms a magnetic force in proportion to the current to attract the touchscreen device to the tip. The drive circuit is configured to receive a haptic force signal and change the magnetic force by changing the current depending on the haptic force signal, wherein the haptic force signal changes depending on the relative position of the tip with respect to the sensing surface of the touchscreen device.

[0073] In some implementations, the touchscreen stylus further includes a force sensor that responds to the contact force of the tip of the touchscreen stylus on the sensing surface of the touchscreen device, and the drive circuit is configured to further change the current depending on the output of the force sensor. In some implementations, the magnetic touchscreen device includes a permanent magnet, and the drive circuit is configured to reverse the direction of the current to apply a magnetic repulsive force on the touchscreen device. In some implementations, the permanent magnet forms a uniform magnetic field at the sensing surface of the touchscreen device.

[0074] Another aspect of the present disclosure relates to a method of providing haptic feedback to a user of a touchscreen device, the method comprising: identifying a relative position of a tip of a touchscreen stylus with respect to a sensing surface of the touchscreen device; asserting a haptic force signal that varies depending on the relative position; and passing a controlled variable current through an electromagnetic circuit to apply a magnetic force between the touchscreen device and the touchscreen stylus, wherein the current varies depending on the haptic force signal.

[0075] In some implementations, the magnetic force includes an attractive force between the touchscreen stylus and the sensing surface of the touchscreen device. Here, the attractive force applies a frictional force between the tip of the touchscreen stylus and the sensing surface, and the frictional force can be proportional to the attractive force. In some implementations, the method further includes time modulating the current such that the attractive force and the frictional force are similarly modulated. In some implementations, the electromagnetic circuit through which the controlled variable current passes is an electromagnetic circuit of the touchscreen device, and the tip of the touchscreen stylus includes a permanent magnet or a ferromagnetic material. In some implementations, the electromagnetic circuit through which the controlled variable current passes is an electromagnetic circuit of the touchscreen device, and the tip of the touchscreen stylus includes a permanent magnet or a ferromagnetic material. In some implementations, the method further includes sensing a contact force between the tip of the touchscreen stylus and the sensing surface of the touchscreen device, wherein passing the controlled variable current through the electromagnetic circuit includes adjusting the current in a closed-loop manner such that the contact force approaches a controlled variable setpoint.

[0076] It will be understood that the configurations and / or approaches described herein are exemplary in nature, and these specific embodiments or examples should not be considered limiting as many variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. Thus, the various acts illustrated and / or described may be performed in the illustrated and / or described order, in other orders, in parallel, or omitted. Similarly, the order of the processes described above may be changed.

[0077] The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various configurations, attributes, functions, processes, acts, and other features disclosed herein, as well as any and all equivalents thereof.

Claims

1. A touch screen device for providing haptic feedback to a user, comprising: A position sensor configured to sense a relative position of a magnetic tip of a touch screen stylus with respect to a sensing surface of the touch screen device, the position sensor including a capacitive sensing electrode array having a plurality of excitation electrodes; An electromagnetic circuit integrated into the excitation electrodes of the electrode array of the position sensor, the electromagnetic circuit including parallel excitation electrodes in the electrode array carrying current in opposite directions, the electromagnetic circuit carrying current and forming a magnetic force proportional to the current to attract the magnetic tip to the sensing surface; A drive circuit in the touch screen device configured to receive a haptic force signal and change the magnetic force by changing the current depending on the haptic force signal, wherein the haptic force signal changes depending on the relative position; And A force sensor responsive to a contact force of a tip of the touch screen stylus on the sensing surface, and wherein the drive circuit is configured to change the current in a closed-loop manner depending on an output of the force sensor.

2. The touch screen device according to claim 1, wherein the electromagnetic circuit is one of a plurality of electromagnetic circuits of the touch screen device, each electromagnetic circuit carrying current and forming a magnetic field extending into a corresponding area outside the touch screen device proportional to the current, and wherein the drive circuit is configured to independently change the current in each of the plurality of electromagnetic circuits depending on the haptic force signal to thereby control the magnetic field in each of the corresponding areas.

3. The touch screen device according to claim 2, wherein the touch screen stylus is one of a plurality of touch screen styli that can be used concurrently on the touch screen device, wherein the position sensor is configured to sense a relative position of a tip of each of the touch screen styli with respect to the sensing surface, and wherein the drive circuit is configured to independently change the current in each of the plurality of electromagnetic circuits depending on a haptic force signal provided independently for each touch screen stylus.

4. The touch screen device according to claim 1, wherein the electromagnetic circuit includes a plurality of concentric windings formed at intersections of the excitation electrodes and sensing electrodes of the electrode array.

5. The touch screen device according to claim 1, wherein the magnetic tip includes a permanent magnet, and wherein the drive circuit is configured to reverse a direction of the current to apply a magnetic repulsive force on the touch screen stylus.

6. The touch screen device according to claim 1, wherein the force sensor includes a resistive touch screen overlay integrated with a capacitive position sensor.

7. A touch screen stylus for a touch screen device according to any one of claims 1 to 6, the touch screen stylus comprising: An electromagnetic circuit disposed at a tip of the touch screen stylus, the electromagnetic circuit carrying current and forming a magnetic force proportional to the current to attract the touch screen device to the tip; And A drive circuit configured to receive a haptic force signal and to change the magnetic force by changing the current depending on the haptic force signal, wherein the haptic force signal changes depending on the relative position of the nib with respect to the sensing surface of the touchscreen device.

8. The touchscreen stylus according to claim 7, further comprising a force sensor responsive to a contact force of the nib of the touchscreen stylus on the sensing surface of the touchscreen device, wherein the drive circuit is configured to further change the current depending on the output of the force sensor.

9. The touchscreen stylus according to claim 7, wherein the touchscreen device includes a permanent magnet, and wherein the drive circuit is configured to reverse the direction of the current to apply a magnetic repulsive force on the touchscreen device.

10. The touchscreen stylus according to claim 9, wherein the permanent magnet forms a uniform magnetic field at the sensing surface of the touchscreen device.

11. A method of providing haptic feedback to a user of a touchscreen device, the method comprising: using a position sensor of the touchscreen device to identify the relative position of the nib of a touchscreen stylus with respect to the sensing surface of the touchscreen device; using a drive circuit in the touchscreen device to receive a haptic force signal, the drive circuit changing a magnetic force between the touchscreen device and the touchscreen stylus by changing a current, wherein the haptic force signal changes depending on the relative position of the nib of the touchscreen stylus; passing a controlled variable current through an electromagnetic circuit of the touchscreen device to apply a magnetic force between the touchscreen device and the touchscreen stylus; and using a force sensor of the touchscreen device to sense a contact force between the nib of the touchscreen stylus and the sensing surface of the touchscreen device, wherein passing the controlled variable current through the electromagnetic circuit includes adjusting the current in a closed-loop manner by the drive circuit in the touchscreen device such that the contact force reaches a controlled variable set value, wherein the magnetic force includes an attractive force between the touchscreen stylus and the sensing surface of the touchscreen device, wherein the attractive force applies a frictional force between the nib of the touchscreen stylus and the sensing surface, and wherein the frictional force is proportional to the attractive force.

12. The method according to claim 11, further comprising: Time modulating the current such that the attractive force and the frictional force are modulated equally.

13. The method according to claim 11, wherein the nib of the touchscreen stylus includes a permanent magnet or a ferromagnetic material.

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