Stylus speed

Abstract

A device for use with a touch surface digitizer, the device comprising: a sensor configured to receive uplink signals emitted by an antenna grid in the digitizer; and a controller configured to detect the uplink signals via the sensor; wherein the controller is further configured to determine a velocity of the device based on a sequence of uplink signals detected at the sensor from one or more nodes of the antenna grid relative to a predetermined spatial pattern of uplink signals emitted across the grid.

Description

Technical Field

[0001] The present invention relates to determining the movement of a device such as a stylus on a digitizer. Background Art

[0002] Many touch-sensitive computing devices employ an active stylus to enhance touch interactions. Determination of the position of the stylus can be provided via electrostatic communication (i.e., between the stylus and the touch sensor of the host computing device) and enable other functions in such systems. The host computing device and its various components (display, capacitive touch sensor, etc.) are sometimes collectively referred to herein as a "digitizer." The stylus emits a signal that is detected by an antenna grid in the digitizer to detect the position of the stylus. Summary of the invention

[0003] Determining the velocity of a stylus as it moves across a digitizer can be useful for certain applications. For example, the velocity can be used to determine the kind of stroke a user is making, or the level of tactile feedback to be provided to the user. One way to do this is to detect the velocity at the digitizer by detecting changes in the detected stylus position in the normal manner. However, if a velocity reading is required at the stylus (such as in order to give tactile feedback), this method is relatively slow because the velocity information must be transmitted back to the stylus. A known method for estimating velocity at the stylus itself is to use an accelerometer on the stylus. However, this is quite inaccurate. Similar problems can also affect other devices used for writing or indicating positions on a digitizer.

[0004] According to a first aspect of the present disclosure, there is provided a device for use with a touch surface digitizer, the device comprising: a sensor configured to receive an uplink signal emitted by an antenna grid in the digitizer; and a controller configured to detect the uplink signal via the sensor;

[0005] Wherein the controller is further configured to determine the speed of the device based on a sequence of uplink signals detected at the sensor from one or more nodes of the antenna grid relative to a predetermined spatial pattern of uplink signals emitted across the grid.

[0006] Thus, the calculated velocity of the device is quickly provided at the device (e.g., stylus) itself for use in desired application functions implemented at the device (rather than a digitizer unit) and with an accuracy that is not achievable using prior art stylus-based techniques.

[0007] This Summary is provided to introduce a selection of concepts in a simplified form that are also 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] For a better understanding of the present invention and to show how it may be carried into effect, reference will now be made, by way of example, to the following drawings, in which:

[0009] Figure 1 A typical digitizer and stylus system is shown;

[0010] Figure 2 A schematic block diagram of a stylus and digitizer system is shown;

[0011] Figure 3 An example implementation of a digitizer with an antenna grid is shown;

[0012] Figure 4 is a timing diagram of two example check signals, with the non-inverted check signal below the inverted check signal;

[0013] Figure 5 An example of a spatial distribution pattern of an uplink signal that varies across the antenna grid of a digitizer is shown;

[0014] Figure 6 is a table showing how combinations of non-inverted ping signals and inverted ping signals combine to create an uplink signal detected by a stylus;

[0015] Figure 7 Three example traces of a stylus on a digitizer are shown;

[0016] Figure 8 The verification signal and data signal during the digitizer transmission cycle are shown. DETAILED DESCRIPTION

[0017] Determining the speed of the stylus as it moves across the digitizer can be useful for certain applications. For example, the speed can be used to determine the kind of stroke the user is making. This is in addition to information such as tip pressure and the angle of the stylus to the surface it is writing on (the plane of the digitizer). Typically this speed information is determined by the digitizer. This is because the digitizer already determines the position of the stylus at any given moment and therefore the additional determination of the speed of the stylus is relatively simple. However, if the stylus itself needs to use this speed information to implement application functionality, the speed information determined by the digitizer must be transmitted from the digitizer to the stylus at some point in time.

[0018] Typically, the process of transmitting velocity information from the digitizer to the stylus takes a certain amount of time. Therefore, by the time the stylus can act on the velocity information, the actual velocity of the stylus may have changed. This introduces a certain amount of lag between the actual velocity of the stylus as specified by the user and the velocity information responded to by the stylus application. This delay may be perceived by the user of the stylus. For example, if the velocity is used to provide certain types of sensory feedback, the user will perceive that the sensory feedback changes at a different time than their own stylus movement. Even the slightest difference may be noticed by some users. This delay can weaken the user experience of the stylus because such differences may become annoying or distracting. For example, this application is providing tactile feedback. The tactile motor strength can be proportional to the stylus velocity. Another example can be that the light on the stylus is configured to flash or change color corresponding to the stylus velocity.

[0019] The inventors have realized that in order to eliminate the delay in communicating the speed of the stylus to the stylus itself, it is necessary to determine the speed at the stylus. Existing hardware for implementing this configuration typically involves the use of an accelerometer in the stylus, which can measure the appropriate acceleration of the stylus from the forces exerted on the accelerometer as the stylus moves, thereby determining the change in speed of the stylus over time. Therefore, the speed measured by the accelerometer is relatively inaccurate over the small distances involved (for example, a stroke when writing), and is too noisy to determine the exact speed of the stylus. This is because the speed is determined by integrating the acceleration. However, since there are still some unknowns, the integration can only be so accurate. This inaccuracy can be called noise, and the determined speed is therefore also called noisy.

[0020] It has been recognized that a need exists for a method of determining the speed of a device at the device and providing the measured speed with little or no noise.

[0021] The present application describes a device (eg, a stylus), a digitizer, and a method for determining the velocity of the device.

[0022] It should be understood that the input device (i.e., a pointing or indicator device) is not necessarily limited to a stylus. Other devices for use with a digitizer may also have their speed determined in the manner described herein. For example, the input device may be a glove, a ring, a sleeve, or a hat, etc. All of these examples may also be configured to provide tactile feedback in response to determining the speed at which the input device is moving on the digitizer. The embodiments herein will be described with reference to a stylus as an example, but it will be understood that this is not necessarily limiting, and more broadly, any technology disclosed herein may also be applicable to any type of indicator device used to write, point, or otherwise indicate a position on a digitizer.

[0023] This article describes how to add dedicated circuitry connected to the digitizer antennas so that each antenna transmits a verification signal during the digitizer transmission cycle. As the stylus moves across the digitizer, it receives verification signals from multiple antennas as uplink signals. The uplink signal is different depending on the position of the stylus on the digitizer. That is, the uplink signal varies spatially above the digitizer in a predetermined pattern. The stylus itself can determine its movement across the digitizer within multiple digitizer transmission cycles based on the received uplink signal sequence, and thus determine its speed accordingly. The verification signal is separate and different from any other signal (e.g., data signal) transmitted from the digitizer to the stylus.

[0024] That is, the stylus may include a sensor tip for receiving uplink signals from an antenna grid in the digitizer. The uplink signals received via the sensor tip are detected by a controller of the stylus, and the velocity of the stylus may be determined based on a sequence of detected uplink signals from nodes of the antenna grid and how the sequence correlates to a predetermined and predefined spatial pattern of uplink signals emitted by the grid.

[0025] In various embodiments, a digitizer for use with the stylus may include a grid of crisscross antennas that emit uplink signals from each node. In this case, the uplink signal may include two interference verification and / or anti-phase verification signals. A signal generator module in the digitizer may be used to generate the verification signal. The electronic circuit system of the digitizer (which is arranged to connect each antenna in the grid to the signal generator to provide multiple uplink signals) allows the uplink signals detected by the stylus to be different at any two adjacent nodes of the grid.

[0026] The stylus and digitizer can be used together to determine the speed of the stylus on a digitizer (e.g., a touch screen). This is achieved by transmitting uplink signals from multiple nodes of an antenna grid in the digitizer during each digitizer transmission cycle. The uplink signals are then detected by the stylus from one or more nodes of the antenna grid within at least two digitizer transmission cycles. Based on the detected uplink signal sequence received at the stylus, the stylus can then determine the speed of the stylus. The digitizer can be, for example, a digitizer of a touch screen or other such touch surface.

[0027] Figure 1A typical digitizer and stylus system 100 is shown. The digitizer 102 includes a plurality of row antennas 104 and column antennas 106. There are nodes 110 where each row antenna 104 intersects with a column antenna (or vice versa). These nodes are typically used to determine the position of the stylus using electrostatic forces. As the stylus 108 moves across the digitizer, it interacts with the nodes and allows the digitizer to determine certain information, such as the stylus position. Data can also be transmitted between the stylus 108 and the digitizer 102.

[0028] Figure 2 Shows Figure 1 1 is a schematic block diagram of a stylus and digitizer system 100. The stylus 108 includes a controller 202 and a sensor tip 204. The controller is connected to the sensor tip 204, and the sensor tip 204 acts as a transmitter and receiver for communicating with the digitizer 108, including uplink signals 206. The controller 202 determines what data is transmitted to and from the digitizer 102 and is responsible for performing actions in response to the uplink signals 206 sent by the digitizer 102.

[0029] Digitizer 102 includes an antenna grid 208 (e.g., including rows 104 and columns 106), a ping signal generator 210, and dedicated circuitry 212 for connecting ping signal generator 210 to antenna grid 208. The ping signal transmitted by the antenna may be detected by stylus tip 204 as uplink signal 206.

[0030] The stylus may also include local storage 214. This may be used to store information about the digitizer with which the stylus is being used, such as the spatial pattern of uplink signals (described in more detail below) or multiple uplink sequences (described in more detail below).

[0031] Figure 3 An example implementation of the digitizer 102 is shown with an antenna grid 208 including: Figure 1 The row antennas 104 and the column antennas 106 in FIG. Figure 3 Specific dedicated circuitry 212 is further included. Dedicated circuitry 212 includes circuitry for providing a check signal to each antenna in grid 208. Alternating row antennas 104 and alternating column antennas 106 are also provided with NOT gates or signal inverters 302. NOT gates 302 invert the check signal before it reaches the antenna. Thus, alternating row antennas 104 and alternating column antennas 106 are provided with an inverted check signal relative to the generated check signal.

[0032] The verification signal generator 210 provides the generated verification signal to the dedicated circuit system 212. When the signal is passed into each antenna, it passes through or does not pass through the NOT gate. For those antennas with NOT gates, the verification signal is inverted. Since the antennas overlap at the nodes, the verification signals also overlap at the nodes, which causes the verification signals to interfere with each other. Since the alternating antennas output inverted verification signals and non-inverted verification signals, the interference appears as a predetermined signal pattern across the surface of the digitizer. The signal at any point or node 110 (or its immediate vicinity) of the grid 208 is an uplink signal 206 detected by the sensor tip 204 of the stylus 108.

[0033] For example, at node 110a, a particular column antenna does not have a NOT gate 302, so the antenna is outputting a normal check signal that is generated. A particular row antenna also does not have a NOT gate 302, so the antenna is also outputting a normal check signal. The interference between the two 'normal' (non-inverted) check signals output at node 110a is therefore constructive interference, in which two identical check signals reinforce each other. The resulting uplink signal (the check signals combined after interfering with each other) is therefore a 'normal' check signal with a higher amplitude or strong signal strength. The 'normal' check signal can be more simply viewed as a '1' bit signal. Therefore, node 110a provides a strong '1' signal.

[0034] At node 110b, a particular column antenna has a NOT gate 302, so that antenna is outputting an inverted check signal. A particular row antenna also has a NOT gate 302, so that antenna is also outputting an inverted check signal. The interference between the two inverted check signals output at node 110b is therefore constructive interference, in which two identical check signals reinforce each other. The resulting uplink signal (the check signals combined after interfering with each other) is therefore an inverted check signal with a higher amplitude or strong signal strength. The inverted check signal can be more simply viewed as a '0' bit signal and as opposed to a '1' signal. Therefore, node 110b provides a strong '0' signal.

[0035] At node 110c, a particular column antenna has a NOT gate 302, so the antenna is outputting an inverted interrogation signal. A particular row antenna does not have a NOT gate 302, so the antenna is outputting a 'normal' (non-inverted) interrogation signal. The interference between the inverted interrogation signal outputted at node 110c and the 'normal' interrogation signal outputted is therefore destructive interference, wherein the two different and opposing interrogation signals cancel each other out. The resulting uplink signal (the interrogation signal combined after interfering with each other) is therefore no signal. The two signals have canceled each other out so that the uplink signal is not detected and therefore node 110c provides no signal, which can be represented by an 'X'.

[0036] It should be understood that there are a variety of ways to arrange the circuit system 212 to provide this arrangement of alternating normal and anti-phase interrogation signals to the antenna grid 208, wherein Figure 3 The arrangement shown is just one example. Another example could be to arrange the dedicated circuitry so that two parallel subcircuits (one for the inverted ping signal and one for the 'normal' ping signal) could connect the ping signal generator 210 to alternate antennas (connected together). Thus, only a single NOT gate would be needed in one subcircuit to provide the inverted ping signal to all antennas in the group of antennas.

[0037] Figure 4 Two example check signals are shown, one 'normal' and one inverted (the normal check signal has passed through the NOT gate 302). The signal 402 below represents the 'normal' check signal or '1' signal, and may be referred to as a positive signal. The signal 404 above represents the inverted check signal (obtained by inverting the 'normal' check signal) followed by a '0' signal, and may be referred to as a negative signal. It can be seen that by inverting the 'normal' check signal, the peaks become valleys and the valleys become peaks, which provides a signal that is considered to be relative. It is easy to see from this representation how the two signals can overlap or combine to cancel each other out given a 'normal' check signal and an inverted check signal.

[0038] The total period of the check signal 406 is short compared to the total length of the digitizer transmission cycle. This is because a more complex signal is not necessary. The signal only needs to be able to be detected as being present or absent in both normal and inverted form. This helps make the detection process as fast as possible and thereby helps reduce delays in determining the stylus velocity later in the process.

[0039] Figure 5 An example of a spatial distribution pattern of uplink signal 206 as it varies across antenna grid 208 is shown. Figure 5 The pattern in particular refers to the above reference Figure 3 and 4 Implementation described. Antenna grid 208 is shown as a dashed line in the background. Above antenna grid 208 are boxes, each box representing a different node of grid 208 and the area around that node. When the stylus tip is within any of these boxes, a different uplink signal is detected. The specific uplink signal detected is represented within each box using the '1', '0', and 'X' characters previously described. It can be seen that no two adjacent boxes contain the same character, and therefore the corresponding uplink signals detected by the stylus tip 204 differ in the same manner. This spatial pattern allows the movement of the stylus to be determined by the stylus based on the received uplink signals.

[0040] Figure 6 The table shows how a 'normal' ping signal - '1' and an inverted ping signal - '0' can combine to create an uplink signal 206 that is detected by the stylus 108. The uplink signal is detected once in each transmission cycle of the digitizer. That is, once each time the digitizer goes through its transmission cycle, a ping signal is sent from an antenna in the grid 208, an uplink signal is sent from the digitizer, and the stylus detects the uplink signal of the portion of the grid 208 to which it is closest.

[0041] Figure 7 Three example traces 702 of stylus 108 on digitizer 102 are shown. The first trace 702a is the result of stylus 108 not moving on digitizer 102. As a result, the sequence of uplink signals received by the stylus is 1, 1, 1, 1. As each uplink signal is received in a single periodic digitizer transmission cycle, the stylus can use this information to determine its velocity. Because the uplink signal does not change throughout the sequence, the stylus knows that it is not moving. And because the digitizer's transmission cycle is periodic, and therefore the time between uplink signals is a known constant time, the stylus also knows how long it has been stationary.

[0042] The second trace 702b is the result of the stylus moving in a diagonal straight line across the surface of the digitizer 102. This results in the uplink signal sequence received by the stylus being 1, 0, 1, 0, 1. The stylus knows from this that it has moved from a positive signal to a negative signal, which corresponds to the diagonal distance between the nodes of the grid 208. The stylus knows that it has moved that distance four times in the time of four digitizer cycles, and therefore knows the time it took to move that distance. Since the stylus can determine the distance it has moved and the time in which it has moved that distance, the stylus can determine its speed. This calculation can be performed differently from the uplink signal measurement as the stylus travels across the board. This results in a quick and accurate determination of the speed of the stylus at the stylus. Unlike other methods, there is no transmission of speed information from one entity to another. The accuracy of the calculated stylus speed depends only on the length of the digitizer transmission cycle and the spacing between the nodes of the digitizer. The stylus only needs to know the uplink signal changes from one or more previous uplink signals, what the grid intervals are in the corresponding directions to those changes, and the time intervals between uplink signals.

[0043] Dot trace 702c is the result of somewhat random movement across antenna grid 208. The resulting uplink signal sequence detected by stylus 108 will be 1, 0, X, 1, 0, X. The only way a '1' can become a '0' is by moving the stylus diagonally from one node to the next. The only way a '0' can become an 'X' is by moving the stylus parallel to an antenna from one node to the next. Similarly, the only way an 'X' can become zero is by moving the stylus parallel to an antenna from one node to the next. Thus, as explained above, the stylus can calculate its velocity directly from the detected uplink signal sequence by knowing about the spatial pattern of the uplink signal on the digitizer and the timing between uplink signal transmissions.

[0044] That is, calculating the velocity of the stylus can be done by deriving the distance the stylus has moved and the time it has taken to move that distance. This can be based on the duration of receiving different uplink signal instances from different nodes of the antenna grid and the known distances between the nodes transmitting these different uplink signals.

[0045] It will be appreciated that the velocity determined in this manner has an upper limit, wherein if the stylus moves across more than one node between uplink signals, uplink signal characters in the sequence will be lost and the velocity will be calculated incorrectly. However, by properly balancing the distance between nodes and the timing between uplink signal transmissions, the velocity of the stylus can be calculated both quickly and accurately when performing typical movements on a digitizer (e.g., writing, drawing, playing games, etc.).

[0046] Figure 8 Figure 1 shows the ping signal and data signal during a digitizer transmission cycle. In each cycle, there is a ping signal (output by a single antenna) and there may also be a data signal. The data signal may include data such as encryption keys for a dedicated Bluetooth channel or digitizer status. The ping signal is Figure 8 , however, the verification signal can be easily placed at the end of the transmission cycle, such as after any data. As long as the verification signal is transmitted at regular time intervals (i.e., once per transmission cycle), the position within the transmission cycle of the digitizer is not important.

[0047] Below are several examples of the velocity of a stylus with the example traces above and example configurations of a digitizer.

[0048] For example, a digitizer may have an antenna spacing of 4 mm between parallel antennas in both rows and columns. This is sometimes referred to as antenna spacing. The transmission cycle of the digitizer may have a duration of 15 milliseconds and a check signal duration of 31 microseconds. The check signal may be provided by a dedicated circuit system synchronized with the digitizer cycle. Thus, the check signal is part of the digitizer transmission cycle or window. Since the uplink signal (combined check signal) is observed as part of the transmission window, the stylus will receive it and measure it. Thus, based on the uplink signal measurement (every 15ms), the stylus can evaluate its speed compared to the digitizer.

[0049] For the first example trace 702a, the detected sequence is 1, 1, 1, 1, 1. It is straightforward to determine from this sequence that the stylus has not moved between the received uplink signals. Therefore, the velocity of the stylus is determined to be zero.

[0050] In the second example trace 702b, the detected uplink signal sequence is 1, 0, 1, 0, 1. By knowing the spatial pattern of the uplink signal of the digitizer (e.g., stored in the local storage of the stylus), it can be determined that the stylus has moved diagonally across the digitizer. Based on the known antenna spacing, the uplink signal sequence can be determined to correspond to a specific distance. In this example, five uplink signals are received, one every 15 milliseconds. Therefore, the speed of the pen can be determined by dividing the determined distance by the time it takes to receive the uplink signal sequence. For this second example trace 702b, the speed of the stylus is determined to be approximately 0.38 meters per second (m / s). This includes four diagonal distances across the digitizer (each approximately 5.66 mm) divided by the time it takes to transmit five uplink signals (4x15ms).

[0051] For the third example trace, the detected uplink signal sequence is 1, 0, X, 1, 0, X. This trace can be considered to be more random. As seen based solely on this sequence, the distance corresponds to a combination of an oblique movement between nodes and an adjacent movement between nodes. For example, the distance consists of the maximum distance including: an oblique movement (about 5.66mm), two adjacent movements after (4mm plus 4mm), an oblique movement after (5.66mm), and a final adjacent movement (4mm). This distance divided by the time (5x15ms) spent transmitting six uplink signals gives the stylus a speed of about 0.31m / s.

[0052] If the antenna spacing is 4 mm, the stylus can measure a maximum velocity of approximately 0.38 m / s. This corresponds to the straightest line along the longest dimension between the digitizer nodes (eg, trace 702b).

[0053] In another example, the detected uplink signal may be 1, 1, 0, 0, X, X, 1, 1, etc. This corresponds to the stylus following the same trajectory as example 702c, but at half speed. Figure 7 , it can be seen how the stylus will spend twice as long in the vicinity of each node so that the uplink signal from each particular node will be received twice. The calculation in the above example will provide a velocity measurement of approximately 0.15 m / s for this detected uplink signal sequence.

[0054] In various embodiments, the stylus may not calculate the velocity directly based on the detected uplink sequence and knowledge of the spatial pattern of the uplink signal at the digitizer, but may simply match the sequence to one of a plurality of predetermined sequences stored locally at the stylus. The predetermined sequence corresponds to a predetermined velocity of the stylus. This is possible when the spatial pattern of the uplink signal at the digitizer is known in advance and thus the velocities of the possible uplink signal sequences can be calculated in advance.

[0055] It will be appreciated that the above scheme is described by way of example only. More generally, any predetermined spatial pattern of uplink signals may be used across the surface of the digitizer, provided that the controller 202 of the stylus is programmed with information about what corresponding uplink signal sequences are expected for one or more possible paths of the stylus on the digitizer.

[0056] In various embodiments, a more complex uplink signal may be used. For example, instead of a single bit '1' and '0' type check signal, a 3-bit signal modulation may be used. With a 3-bit check signal, the uplink mode will be able to provide 8 different characters or symbols (e.g., not just '1', '0', and 'X' as in the above example). This 3-bit signaling will be able to provide more accurate speed detection. However, 3 bits will require more bits to be spent on the check signal. Therefore, even though a more accurate system will be achieved, it may take longer to implement the system at the stylus.

[0057] In various embodiments, the signal modulation used is DSSS signal modulation. This type of signal modulation allows large amounts of information to be sent quickly with relatively low complexity. This allows for faster processing and therefore faster determination of stylus velocity. It should be understood that other signal modulation formats may be used to achieve the purpose of determining stylus velocity based on the spatially varying pattern of signals at the digitizer and the detected sequence of these signals at the stylus. Any signal that varies from antenna to antenna may be used.

[0058] Using a different signal modulation for those signals described above may require modifying the hardware described above to accommodate that signal modulation.An example of this modified version of the presently described method is described below.

[0059] It should be understood that the above method for determining the velocity of the stylus at the stylus can be implemented with any spatially repeating pattern. For example, any pattern of signals that can be output by the antenna of the digitizer will enable the above technique to be implemented.

[0060] In an alternative embodiment, the spatial pattern may not be provided by an interference check signal at the node, but by individual antennas instead of nodes. That is, in another alternative or additional variant, the antenna grid of the digitizer does not necessarily have to take the form of a criss-cross or intersecting antenna grid. In another example, the grid may include a separate antenna at each uplink "pixel" position. In this embodiment, the spatial pattern can be provided by simply providing a specific signal to each antenna. In some possible implementations, the signal output at each antenna in this embodiment can even be unique across the entire digitizer grid. This arrangement will allow each sequence to also provide information about the direction of motion of the stylus. It should be understood that this embodiment will most likely require a set of dedicated antennas, rather than using an existing antenna grid as in the above-described embodiment. The separate antenna embodiment will also need to provide a large number of different signals to each antenna so that these antennas can be more clearly distinguished. However, implementing a large but repeated collection of uplink signals will be sufficient to enable the possible direction of motion of the stylus to be determined with a high enough probability of providing useful information.

[0061] In the above description, many specific details are set forth to provide a more thorough understanding of the described embodiments. However, it is apparent to those skilled in the art that the described embodiments may be practiced without one or more of these specific details. In other cases, well-known features are not described to avoid obscuring the described embodiments.

[0062] References throughout this disclosure to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the various appearances of the phrases "in one embodiment" or "in an embodiment" throughout this specification are not necessarily all references to the same embodiment, but may refer to the same embodiment. Furthermore, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner.

[0063] Generally, any of the functions described herein can be implemented using software, firmware, hardware (eg, fixed logic circuitry), or a combination of these implementations. Figure 2The modules and steps shown separately in the figure may or may not be implemented as separate modules or steps. As used herein, the terms "module", "functionality" and "component" generally represent software, firmware, hardware or a combination thereof. In the case of software implementation, a module or function represents a program code that performs a specified task when executed on a processor (e.g., one or more CPUs). The program code may be stored in one or more computer-readable memory devices. The features of the technology described herein are platform-independent, which means that the technology can be implemented on various commercial computing platforms with various processors. For example, a user device may also include an entity (e.g., software) that enables the hardware of the user device to perform operations, such as a processor, a function block, etc. For example, a user device may include a computer-readable medium, which may be configured to maintain instructions that enable the user device (and in particular the operating system and associated hardware of the user device) to perform operations. Therefore, these instructions are used to configure the operating system and associated hardware to perform these operations, and in this way cause the operating system and associated hardware to transform to perform each function. Instructions may be provided to the user device by a computer-readable medium through various different configurations.

[0064] One such computer-readable medium configuration is a signal-bearing medium, and is thus configured to transmit instructions (e.g., as a carrier wave) to a computing device, such as via a network or the like. Computer-readable media may also be configured as a computer-readable storage medium and thus not a signal-bearing medium. Examples of computer-readable storage media include random access memory (RAM), read-only memory (ROM), optical disk, flash memory, hard disk memory, and other memory devices that may use magnetic, optical, and other technologies for storing instructions and other data.

[0065] It will be appreciated that the above embodiments are described by way of example only.

[0066] Although the above description relates to a stylus with a sensor tip, it should be understood that the pointing device is not necessarily limited to a stylus. Other devices for use with a digitizer may also have their speed determined in the manner described above, and may include sensors that are not necessarily sensor tips. For example, the device may be a glove worn on the hand that includes a circuit system for interacting with the digitizer. As another example, the device may be a ring-type device worn around the fingers of the hand and include a circuit system for interacting with the digitizer. As yet another example, the device may be a sleeve or hat-type device for wearing on one or more fingers of the hand and include a circuit system for interacting with the digitizer. All of the above examples may also be configured to provide tactile feedback in response to determining the speed of movement of the device on the digitizer.

[0067] More generally, according to one aspect disclosed herein, there is provided a device for use with a touch surface digitizer, the device comprising: a sensor configured to receive uplink signals emitted by an antenna grid in the digitizer; and a controller configured to detect the uplink signals via the sensor; wherein the controller is further configured to determine a velocity of the device based on a sequence of uplink signals detected at the sensor from one or more nodes of the antenna grid relative to a predetermined spatial pattern of uplink signals emitted across the grid.

[0068] In various embodiments, the sequence includes the detected uplink signal state. Possible states may be a strong positive signal or '1' (two constructively interfering positive signals), a strong negative signal or '0' (two constructively interfering negative signals), or no signal 'X', where the positive and negative signals have destructively interfered with each other.

[0069] In various embodiments, the uplink signal sequence is an interference check signal sequence.

[0070] In various embodiments, the device may be a stylus and the sensor may be a sensor tip of the stylus.

[0071] In various embodiments, the device may be a stylus, a glove, a ring, a hat or sleeve device, etc.

[0072] In various embodiments, the controller is configured to match the detected uplink signal sequence with one of a plurality of predetermined sequences stored in a local memory of the device, wherein each predetermined sequence corresponds to a predetermined speed of the device.

[0073] In various embodiments, the controller is configured to calculate the speed of the device by using the detected uplink signal pattern to derive a distance moved by the device and a time for the device to move the distance.

[0074] In various embodiments, the controller is configured to derive the distance moved by the device based on the duration of different uplink signal instances received from different nodes of the antenna grid and the known distances between the nodes transmitting the different uplink signals.

[0075] In various embodiments, the antenna grid includes a plurality of row antennas and column antennas, antennas alternating across rows alternately emitting a verification signal and an anti-phase verification signal, and antennas alternating across columns alternately emitting a verification signal and an anti-phase verification signal; each of the detected uplink signals is emitted at a node of a different corresponding combination of one of the row antennas and one of the column antennas; and the corresponding uplink signals are formed by constructive or destructive interference of the verification signals and / or the anti-phase signals with each other.

[0076] In various embodiments, in response to determining a velocity of the device, the controller is configured to activate a device component to provide a level of haptic feedback corresponding to the determined velocity.

[0077] According to a second aspect disclosed herein, there is provided a touch surface digitizer for use with an electronic device, the digitizer comprising: an antenna grid configured to emit an uplink signal from each of a plurality of nodes; a signal generator module for generating a verification signal; and an electronic circuit system arranged to connect each antenna in the grid to the signal generator to provide a plurality of uplink signals, wherein the digitizer is configured such that the uplink signals are detected by the device as being different at any two adjacent nodes of the grid.

[0078] In various embodiments, the uplink signal detected by the device includes two interference ping and / or anti-phase ping signals.

[0079] In various embodiments, the circuit system includes NOT gates located at alternating antennas of the grid in both row and column directions.

[0080] In various embodiments, the uplink signal is a spatially varying signal having a predetermined pattern across the nodes of the mesh.

[0081] In various embodiments, the ping signal has a duration of 31 microseconds and is transmitted once per 15 millisecond digitizer uplink signal transmission period.

[0082] In various embodiments, the parallel antennas of the grid have a minimum spacing of 4 mm.

[0083] According to a third aspect disclosed herein, there is provided a computer system, comprising: the device for use with a touch surface digitizer as described above; and the touch surface digitizer as described in the second aspect.

[0084] According to a fourth aspect disclosed herein, there is provided a method of determining a velocity of a device on a touch surface digitizer, the method comprising: transmitting uplink signals from a plurality of points on the digitizer in a predetermined spatial pattern during each digitizer transmission cycle; detecting at the device a sequence of uplink signals from at least two of the points in at least two digitizer transmission cycles; and determining the velocity of the device based on the sequence of detected uplink signals combined with information about the spatial pattern.

[0085] In various embodiments, the method includes calculating the speed of the device by deriving the distance moved by the device and the time taken to move the distance based on the duration of receiving different uplink signal instances from different nodes of the antenna grid and the known distances between the nodes transmitting the different uplink signals.

[0086] According to a fifth aspect disclosed herein, there is provided a computer program product comprising code, the code being contained on a computer-readable medium and configured to execute the method as described in the fourth aspect when run on one or more processing units of the computer system as described in the third aspect.

[0087] Although the subject matter of the present invention is described in language specific to structural features and / or method actions, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed as example forms of implementing the claims.

Claims

1. A device for use with a touch surface digitizer, the device comprising: a sensor configured to receive an uplink signal emitted by an antenna grid in the digitizer; as well as a controller configured to detect the uplink signal via the sensor; wherein the controller is further configured to determine a velocity of the device based on a sequence of uplink signals detected at the sensor from one or more nodes of the antenna grid relative to a predetermined spatial pattern of the uplink signals emitted across the grid; The controller is configured to match the detected uplink signal sequence with one of a plurality of predetermined sequences stored in a local memory of the device, wherein each predetermined sequence corresponds to a predetermined speed of the device.

2. The device of claim 1, wherein the controller is configured to calculate the speed of the device by using the detected uplink signal pattern to derive a distance moved by the device and a time taken by the device to move the distance.

3. A device as described in claim 1, wherein the controller is configured to derive the distance moved by the device based on the duration of receiving different uplink signal instances from different nodes of the antenna grid and the known distances between the nodes transmitting the different uplink signals.

4. The apparatus of claim 1, wherein: The antenna grid includes a plurality of row antennas and column antennas, antennas alternating across rows alternately sending out a check signal and an inverted check signal, and antennas alternating across columns alternately sending out a check signal and an inverted check signal; Each of the detected uplink signals is emitted at a junction of a different respective combination of one of the row antennas and one of the column antennas; and Each of the detected uplink signals is formed by the interrogation signals and / or the anti-phase interrogation signals constructively or destructively interfering with each other. 5 . The device of claim 1 , wherein in response to determining a speed of the device, the controller is configured to activate a device component to provide a level of tactile feedback corresponding to the determined speed.

6. A touch surface digitizer for use with a device as claimed in any one of claims 1 to 5, the digitizer comprising: an antenna grid configured to transmit an uplink signal from each of the plurality of nodes; a signal generator module for generating the uplink signal; as well as Electronic circuitry arranged to connect each antenna in the grid to the signal generator to provide a plurality of uplink signals, wherein the digitizer is configured such that the uplink signals are detected by the device as being different at any two adjacent nodes of the grid.

7. The digitizer of claim 6, wherein the uplink signal detected by the device comprises two interference ping and / or anti-phase ping signals.

8. The digitizer of claim 6, wherein the circuit system includes NOT gates located at alternating antennas of the grid in both row and column directions.

9. The digitizer of claim 6, wherein the uplink signal is a spatially varying signal having a predetermined pattern across the nodes of the grid.

10. The digitizer of claim 6, wherein the parallel antennas of the grid have a minimum spacing of 4 mm.

11. A computer system comprising: An apparatus as claimed in any one of claims 1 to 5; A touch surface digitizer as claimed in any one of claims 6 to 10.

12. A method of determining a velocity of a device as claimed in any one of claims 1 to 5 on a touch surface digitizer as claimed in claim 6, the method comprising: transmitting uplink signals from a plurality of points on the digitizer in a predetermined spatial pattern during each digitizer transmission cycle; detecting at the device a sequence of uplink signals from at least two of the plurality of points in at least two digitizer transmission cycles; as well as A velocity of the device is determined based on a sequence of detected uplink signals combined with information about the spatial pattern.

13. The method as claimed in claim 12 includes calculating the speed of the device by the following operation: deriving the distance moved by the device and the time to move the distance based on the duration of receiving different uplink signal instances from different nodes of the antenna grid and the known distances between the nodes transmitting the different uplink signals.

14. A computer-readable storage medium storing code, the code being configured to perform the method of claim 12 or 13 when executed on one or more processing units of the computer system of claim 11.

15. A computer system comprising means for executing the method according to any one of claims 12-13.

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