User input mechanism and method

Abstract

Described is a user input mechanism for providing a signal indicative of a user input to a system communicatively coupled to the user input mechanism. The user input mechanism includes: a capacitive sensing element configured to sense changes in capacitance at one or more locations of the capacitive sensing element; a moveable component moveably mounted with respect to the capacitive sensing element and configured to be moveable by a user of the user input mechanism, wherein the moveable component is provided with one or more electrically conductive regions capable of capacitively coupling to the capacitive sensing element; control circuitry configured to receive signals from the capacitive sensing element and to determine the position of the moveable component relative to the capacitive sensing element; and a feedback mechanism arranged to provide feedback to a user of the user input mechanism. The control circuitry is configured to control the feedback mechanism to provide a feedback signal to the user on the basis of the determined position of the moveable component relative to the capacitive sensing element. Also described is a system and a method.

Description

[0001] TITLE OF THE INVENTION

[0002] USER INPUT MECHANISM AND METHOD

[0003] BACKGROUND OF THE INVENTION

[0004] The present invention relates to the field of user input mechanisms and in particular to moveable user input mechanism that utilise a moveable component, such as a dial, to communicate a user input to a coupled system.

[0005] Many systems employ some form of user input mechanism that allows for a user to interact with the system, e.g., to provide an input for controlling or affecting some function controlled by the system. Many solutions have been proposed over the years, from mechanical-based solutions such as buttons, switches and dials, to more electronic-based solutions such as capacitive touch-sensors or touch-screens. For example, in the automotive industry, touch-screens are becoming increasingly commonplace for vehicle control or infotainment systems, in part due to their versatility and adaptability. However, some users may prefer more mechanical-based solutions, particularly in an automobile such as a car where the user I driver’s attention is directed to the road and easily recognisable I familiar user input mechanisms may be more desired. Such user input mechanisms may be more familiar with certain users or groups of users, which may in part be due to offering a more mechanical or tactile interaction with the user input mechanism which may provide a level or reassurance or confirmation of the user’s input.

[0006] Mechanical user input mechanisms have a tendency to experience wear and tear through use owing to the moving components involved with their operation. This may particularly be the case where the mechanical user input mechanism is provided with mechanisms that provide feedback to user interactions to help indicate the extent to which the user input mechanism has been actuated, such as for example, a slider or a dial that provides a notched movement to indicate switching between different user inputs (e.g., such as switching between different volume levels for an audio speaker or the like).

[0007] In addition, while some users may prefer mechanical-based inputs as described above, the flexibility and adaptability afforded by electronic-based user input mechanisms may be attractive to manufactures and / or other users.

[0008] Hence, there is a desire to provide user input mechanisms which offer the advantages described above in the context of an electronic-based user input mechanism, but which also enable a more mechanical or tactile interaction with the user.

[0009] SUMMARY OF THE INVENTION According to a first aspect of the invention there is provided a user input mechanism for providing a signal indicative of a user input to a system communicatively coupled to the user input mechanism. The user input mechanism includes: a capacitive sensing element configured to sense changes in capacitance at one or more locations of the capacitive sensing element; a moveable component moveably mounted with respect to the capacitive sensing element and configured to be moveable by a user of the user input mechanism, wherein the moveable component is provided with one or more electrically conductive regions capable of capacitively coupling to the capacitive sensing element; control circuitry configured to receive signals from the capacitive sensing element and to determine the position of the moveable component relative to the capacitive sensing element; and a feedback mechanism arranged to provide feedback to a user of the user input mechanism. The control circuitry is configured to control the feedback mechanism to provide a feedback signal to the user on the basis of the determined position of the moveable component relative to the capacitive sensing element.

[0010] According to a second aspect of the invention there is provided a system comprising the user input mechanism of the first aspect, wherein the system is configured to receive the determined position of the moveable component from the processing circuitry of the user input mechanism and to perform a function responsive to the received determined position of the moveable component.

[0011] According to a third aspect of the invention there is provided a method for providing feedback to a user of a user input mechanism for providing a signal indicative of a user input to a system communicatively coupled to the user input mechanism, wherein the user input mechanism comprises a capacitive sensing element to sense changes in capacitance at one or more locations of the capacitive sensing element, a moveable component moveably mounted with respect to the capacitive sensing element and configured to be moveable by a user of the user input mechanism, wherein the moveable component is provided with one or more electrically conductive regions capable of capacitively coupling to the capacitive sensing element, control circuitry configured to receive signals from the capacitive sensing element and to determine the position of the moveable component relative to the capacitive sensing element; and a feedback mechanism arranged to provide feedback to a user of the user input mechanism. The method includes: determining a position of the moveable component relative to the capacitive sensing element; and providing a feedback signal to the user on the basis of the determined position of the moveable component relative to the capacitive sensing element.

[0012] It will be appreciated that features and aspects of the invention described above in relation to the first and other aspects of the invention are equally applicable to, and may be combined with, embodiments of the invention according to other aspects of the invention as appropriate, and not just in the specific combinations described above.

[0013] BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The invention is now described by way of example only with reference to the following drawings in which:

[0015] Figure 1 schematically illustrates a user input mechanism including a rotatable dial in accordance with certain embodiments of the invention;

[0016] Figure 2 schematically illustrates the user input mechanism of Figure 1 viewed from above, and further schematically shows the positions of the a plurality of electrodes forming a capacitive sensing element;

[0017] Figures 3a and 3b schematically illustrates the rotatable dial of the user input mechanism in more detail where Figure 3a shows the rotatable dial in cross-section through the height of the rotatable dial, while Figure 3b show the rotatable dial when viewed from below;

[0018] Figures 4a and 4b schematically illustrates, in plan view, two different positions of the rotatable dial and the corresponding electrically conductive regions of the rotatable dial relative to the plurality of electrodes, where Figure 4a shows the rotatable dial in a first position and Figure 4b shows the rotatable dial in a second position that is rotated by 45° compared to the first position of the rotatable dial;

[0019] Figure 5 schematically illustrates a graph depicting sets of mutual capacitive measurements corresponding to sensor nodes of the user input mechanism of Figures 4a and 4b for two different scenarios for the rotatable dial;

[0020] Figure 6 illustrates schematically illustrates the user input mechanism in cross-section showing the coupling of the rotatable dial to the capacitive sensing element and a haptic feedback mechanism;

[0021] Figure 7 is a flow chart illustrating a method for operating the user input mechanism according to a first example where the processing circuitry of the user input mechanism is adapted to determine whether the position of the rotatable dial corresponds to a predetermined position set in advance and to activate the haptic feedback mechanism if the position of the rotatable dial is determined to correspond to a predetermined position set in advance;

[0022] Figure 8 is a flow chart illustrating a variation of the method in Figure 7 in which the processing circuitry receives user-defined predetermined positions of the rotatable dial;

[0023] Figure 9 is a flow chart illustrating a method for operating the user input mechanism according to a second example where the processing circuitry of the user input mechanism is adapted to determine whether the rotatable dial is being moved and to activate the haptic feedback mechanism if it is determined the rotatable dial is being moved;

[0024] Figure 10 is a flow chart illustrating a method for operating the user input mechanism according to a third example combining the methods of Figures 7 and 9; and

[0025] Figures 11a and 11b schematically show two examples of the rotatable dial having electrically conductive regions that allow the processing circuitry to distinguish between positions of the rotatable dial that are 180° apart, where Figure 11a shows a second electrically conductive region offset from a line of symmetry of the rotatable dial passing through the first electrically conductive region, while Figure 11b shows a second electrically conductive region having a different shape to the first electrically conductive region.

[0026] DETAILED DESCRIPTION

[0027] The present disclosure relates broadly to a user input mechanism. More specifically, the user input mechanism includes a moveable component, such as a rotatable dial, and a capacitive sensing element (comprising an array of electrodes). Processing circuitry is provided to determine the relative position of the moveable component (such as the rotated position of a rotatable dial) to the orientation of the capacitive sensing element. Depending on the determined position of the moveable component, the processing circuitry is capable of causing a feedback mechanism (for example, a haptic feedback mechanism) to provide feedback to the user.

[0028] In this way, the user input mechanism of the present disclosure is capable of providing a user input mechanism having a more “physical” feel to a user (for instance, by allowing a user to grip I rotate I move a component, in a similar manner to more mechanical conventional mechanisms), but which utilises capacitive sensing technology to actually determine the input. This is particularly the case with providing haptic feedback which may be controlled to simulate the mechanical effects that a user may expect when using a moveable component as an input mechanism (e.g., such as when rotating a mechanical dial, and by the mechanical dial engaging notches signifying different user inputs, or to simulate the resistance when moving the moveable component). Accordingly, such mechanical interactions are unnecessary when using the haptic feedback to provide the mechanical sensation, and thus the wear and tear on the moveable component can be reduced when using the capacitive sensing element to detect the position of the moveable component and the haptic feedback to mimic the physical sensations.

[0029] In addition, using capacitive sensing elements can allow for improved flexibility, both in terms of locating the moveable component as well as in respect of the provision of the inputs and of the feedback provided. That is, for example, the user input mechanism may be adapted to provide more or fewer positions corresponding to user inputs without changing any structural features of the moveable component. Additionally, the haptic feedback may be adapted depending on the user inputs and / or user preference. Thus, greater flexibility may be afforded to manufactures of the user input mechanisms.

[0030] Figure 1 schematically shows, in perspective view, a user input mechanism 1 in accordance with aspects of the present disclosure.

[0031] The user input mechanism 1 comprises a capacitive sensing element 100, measurement circuitry 105, processing circuitry 106, (optional) cover 108, and a rotatable dial 130. The sensor element 100, cover 108 and rotatable dial 130 may, more generally, be referred to as a user facing part of the user input mechanism 1 arranged such that the user is able to interact with the rotatable dial 130 of the user input mechanism 1 , while the measurement circuitry 105 and processing circuitry 106 may, more generally, be referred to as the controller (or control circuitry) of the user input mechanism 1.

[0032] The user input mechanism 1 is intended for use with an associated system (not shown in Figure 1) whereby the user input mechanism 1 , and particularly the user facing part of the user input mechanism 1, is arranged such that the user is able to actuate, e.g., grip and rotate, the rotatable dial 130 to signify a desired input. The control circuitry, and in particular the processing circuitry 106, is arranged to determine actuation of the rotatable dial 130 and provide a signal to the associated system indicative of the desired user input, whereby the signal output from the processing circuitry 106 may be used by the associated system to control an associated function. For example, if the associated system performs the function of playing a sound I music, e.g., through a speaker, rotation of the rotatable dial in one direction (e.g., clockwise) may signify a user input associated with increasing the volume of sound output by the speaker of the associated system, while rotation of the rotatable dial in the other direction (e.g., anticlockwise) may signify a user input associated with decreasing the volume of sound output by the speaker of the associated system.

[0033] In some implementations, the user input mechanism 1 may be integrally provided with the associated system. That is, for example, the cover 108 may form a part of the outer surface of any housing of the associated system (e.g., such as the housing of a stereo system or the console of a car). The control circuitry of the user input mechanism 1 may be integrally provided with the control circuitry of the associated system or, alternatively, the control circuitry of the user input mechanism 1 may be communicatively coupled to the control circuitry of the associated system. In other implementations, the user input mechanism 1 may be suitably adapted to be retrofit to the associated system; for example, to replace a mechanical rotatable dial or the like. Figure 2 schematically shows the user input mechanism 1 , and specifically the capacitive sensing element 100, in more detail. Figure 2 shows the user input mechanism 1 in plane view; however, elements of the capacitive sensor element 100 are emphasised for clarity.

[0034] The capacitive sensing element 100 is constructed from a substrate 103 that could be glass, plastic or another insulating material and upon which is arranged an array of electrically conductive electrodes comprising multiple laterally extending parallel electrodes, X-electrodes 101 (row electrodes), and multiple vertically extending parallel electrodes, Y- electrodes 102 (column electrodes). As will be explained in more detail below, the X- electrodes 101 and Y-electrodes 102 (which together may be referred to as an electrode array) define a sensing surface of the capacitive sensing element 100 and are configured to sense an electrically conductive object capacitively coupled to the electrode array 101 , 102, and subsequently to permit a location of the electrically conductive object on the sensing surface of the capacitive sensing element 100 to be determined.

[0035] To clarify the terminology, and as will be seen from Figure 2, the X-electrodes 101 (row electrodes) are aligned parallel to the X-direction and the Y-electrodes 102 (column electrodes) are aligned parallel to the Y-direction. Thus, the different X-electrodes allow the position of an electrically conductive object to be determined at different positions along the Y-direction while the different Y-electrodes allow the position of a conductive object to be determined at different positions along the X-direction. That is to say in accordance with the terminology used herein, the electrodes are named (in terms of X- and Y-) after their direction of extent rather than the direction along which they resolve position. It will however be appreciated these terms are simply used as a convenient way of distinguishing the groups of electrodes extending in the different directions. In particular, the terms are not intended to indicate any specific electrode orientation. In general the term "row" will be used to refer to electrodes extending in a horizontal direction for the orientations represented in the figures while the terms "column" will be used to refer to electrodes extending in a vertical direction in the orientations represented in the figures.

[0036] In the described implementation, the electrodes 101, 102 are arranged on an orthogonal grid, generally with a first set of electrodes on one side of the substrate 103 and the other set of electrodes on the opposite side of the substrate 103 and oriented at substantially 90° to the first set. In other implementations, the electrodes may be oriented at a different angle (e.g., 30°) relative to one another. In addition, it should also be appreciated that it is also possible to provide structures where the grid of electrodes is formed on a single side of the substrate 103 and small conductive bridges are used to allow the two orthogonal sets of electrodes to cross each other without short circuiting. Regardless of the arrangement of the electrodes, broadly speaking, one set of electrodes is used to sense the position of conductive objects in a first axis that we shall call “X” and the second set to sense the position of conductive objects in the second orthogonal axis that we shall call “Y”.

[0037] In some cases, each electrode may have a more detailed structure than the simple "bar" structures represented in Figure 2, but the operating principles are broadly the same. The electrodes 101, 102 are made of an electrically conductive material such as copper or Indium Tin Oxide (ITO). The nature of the various materials used depends on the desired characteristics of the user input mechanism 1. For example, the capacitive sensing element 100 may need to be transparent for use with an underlying display screen or source of illumination (such as one or more LEDs), in which case ITO electrodes and a plastic substrate may be employed. Alternatively, the capacitive sensing element 100 may be opaque, and hence can use lower cost copper electrodes and an epoxy-glass-fibre substrate (e.g. FR4).

[0038] In the example, the cover (also referred to as a lens or panel) 108 is positioned in front of the substrate 103. The cover 108 acts to protect the substrate 103 and electrodes 101 , 102. In this implementation, it is the surface of the cover 108 that forms the sensing surface. In other implementations, the cover 108 may be omitted, for example, in implementations where the electrodes 101, 102 are embedded in the substrate 103. Note that it is not necessary for any electrically conductive object to make direct galvanic connection to the electrodes 101 , 102 in order to be sensed by the capacitive sensing element 100. Rather, an electrically conductive object in the vicinity of the capacitive sensing element 100 is capable of influencing the electric fields that the measurement circuitry 105 generates by driving the electrodes 101 , 102.

[0039] Referring back to Figure 2, the electrodes 101 , 102 are electrically connected via circuit conductors 104 to measurement circuitry 105, which is in turn connected to processing circuitry 106 by means of a circuit conductor 107. The measurement circuitry 105 and I or the processing circuitry 106 may each be provided by a (micro)controller, processor, ASIC or similar form of control chip. Although shown separately in Figures 1 and 2, in some implementations, the measurement circuitry 105 and the processing circuitry 106 may be provided by the same (micro)controller, processor, ASIC or similar form of control chip. The measurement circuitry 105 and I or the processing circuitry 106 may be comprised of a printed circuit board (PCB), which may further include the various circuit conductors 104, 107. The measurement circuitry 105 and the processing circuitry 106 may be formed on the same PCB, or separate PCBs. Note also that the functionality provided by either of the measurement circuitry 105 and the processing circuitry 106 may be split across multiple circuit boards and / or across components which are not mounted to a PCB. The measurement circuitry 105 is configured to perform capacitance measurements associated with the electrodes 101 , 102 (described in more detail below). The measurement circuitry 105 comprises drive circuitry 112 for generating electrical signals to be applied to the electrodes 101 , 102 to allow the capacitance measurements to be made. The measurement circuitry 105 outputs the obtained capacitance measurements to the processing circuitry 106, which is arranged to perform processing on the capacitance measurements.

[0040] In accordance with the present disclosure, the processing circuitry 106 is configured to determine a position of one or more electrically conductive objects relative to the capacitive sensing element 100 (or more specifically, the sensing surface thereof). More particularly, as will be described below, the one or more conductive objects correspond to one or more electrically conductive regions of the rotatable dial 130, and thus the processing circuitry 106 is configured not only to determine the relative locations of the one or more conductive objects of the rotatable dial 130 relative to the capacitive sensing element 100 but also to determine the position of the rotatable dial 130 relative to the capacitive sensing element 100 / sensing surface.

[0041] Figures 3a and 3b schematically show an example configuration of the rotatable dial 130. Figure 3a shows the rotatable dial 130 in cross-section along a diameter of the rotatable dial 130 while Figure 3b shows a view from the lower side of the rotatable dial 130 (where the lower side is the side that is closest to the cover 108 in Figure 1).

[0042] According to the described example, the rotatable dial 130 comprises a main body

[0043] 131 that is cylindrical in shape and has a diameter greater than the height (or thickness) of the rotatable dial 130, as seen in Figure 3a. The main body 131 is generally formed of a non- conductive material, for example a plastic material, and forms an outer surface that is intended to be touched I gripped by a user of the user input mechanism 1. In some implementations, the main body 131 of the rotatable dial 130 is provided with knurling (for example on the outer cylindrical surface of the main body 131) or indentations (for example on the upper circular surface) to help facilitate user interaction with the rotatable dial 130.

[0044] The rotatable dial 130 further comprises one or more electrically conductive regions 132. In the example of Figures 3a and 3b, the electrically conductive regions 132 take the form of a cylindrical mass of electrically conductive material, for example such as a metal. Additionally, as seen in Figure 3b in particular, there are two electrically conductive regions

[0045] 132 offset from the central axis of the rotatable dial 130 (around which the rotatable dial 130 is arranged to rotate) and positioned on opposite sides of the rotatable dial 130. The two electrically conductive regions 132 each project a surface (e.g., the circular surface as seen in Figure 3b) onto the surface of the cover 108 / substrate 103 when the rotatable dial 130 is coupled to the cover 108 / substrate 103. In addition, the electrically conducive regions 132 are discrete electrically conductive regions 132. In this example, the electrically conductive regions 132 are separated from each other by the electrically non-conductive material of the main body 131. In this manner, as discussed in greater detail below, the two electrically conductive regions 132 are capable of providing discrete, detectable signals at the capacitive sensing element 100.

[0046] In the example described above, the two electrically conductive regions 132 are cylindrical in shape and are located in the main body 131 of the rotatable dial 130. For example, in some implementations, the main body 131 may be provided with (e.g., drilled or moulded) two corresponding cylindrical regions into which the cylindrical electrically conductive regions 132 are inserted. However, in other implementations, the electrically conductive regions 132 may take other shapes. For example, instead of a cylindrical shape, the electrically conductive regions 132 may have a generally L-shape configuration, whereby the vertical part of the L-shape is similarly provided in the main body 131 of the rotatable dial, and the horizontal part of the L-shape projects along the lower surface of the rotatable dial 130 (either towards the circumference or toward the central axis). In such a configuration, the horizontal part of the electrically conductive region 132 may be referred to as a wiper, where the wiper passes across the surface of the cover 108 / substrate 103 as the rotatable dial 130 is rotated. In other implementations, the electrically conductive region 132 may be T- shaped. In other implementations, the electrically conductive region 132 may be arc-shaped. The electrically conductive regions 132 may take any shape as desired.

[0047] In the present example, two electrically conductive regions 132 are provided but it should be appreciated that in other implementations only one electrically conductive region 132 may be provided or more than two electrically conductive regions 132 may be provided. When two or more electrically conductive regions 132 are provided, the plurality of electrically conductive regions 132 are arranged such that at least two of the electrically conductive regions 132 form discrete electrically conductive regions, e.g., separated by a dielectric or non-conductive material (such as in the example of Figures 3a, 3b). Regardless of the number of electrically conductive regions 132 provided, the surface projected from each electrically conductive region 132 onto the surface of the cover 108 / substrate 103 (for example, such as the circular surfaces of the electrically conductive regions 132 seen in Figure 3b) does not occupy the entire projected surface of the rotatable dial 130.

[0048] In use, the electrically conductive regions 132 are able to capacitively couple to the electrodes 101 , 102. That is to say, when the rotatable dial 130 is provided, the electrodes 101 , 102 are capable of detecting the electrically conductive regions 132 and positions thereof. In the present example, the electrically conductive regions 132 are positioned such that they are close to the outer perimeter of the main body 131 but are covered by the outer surface of the main body 131. In this way, the electrically conductive regions 132 are protected from direct contact with the user’s hand (e.g., to help avoid degradation or corrosion of the conductive region 132). In other implementations, the surface of the electrically conductive regions 132 may be exposed and be capable of direct contact with the user’s hand. In the example of Figure 3a and 3b, the electrically conductive regions 132 are exposed at a lower surface to the cover 108 / substrate 103, but it should be appreciated that electrically conductive regions 132 may be encased in the main body 131 of the rotatable dial 130 such that there exists a region of the main body 131 between the lower surface of the electrically conductive regions 132 and the upper surface of the cover 108 / substrate 103.

[0049] The rotatable dial 130 is also provided with a recess portion 133 that is arranged to enable coupling of the rotatable dial 130 to a corresponding coupling mechanism that permits movement (e.g., rotation) of the rotatable dial 130 relative to the capacitive sensing element 100. In the described implementation, the recess portion 133 is cylindrical and is sized so as to fit on a cylindrical coupling mechanism 140 (otherwise referred to as spindle 140). The recess portion 133 is sized such that, when engaged with the spindle 140, the rotatable dial 130 is able to rotate about the spindle 140. Although not shown in Figure 3a or 3b, the recess portion 133 may be provided with any suitable mechanism to help engage the rotatable dial 130 with the spindle 140 (e.g., such as one or more latches, grooves, etc.) and / or to help facilitate movement (e.g., such as one or more bearings or the like). In addition, in other implementations, the recess portion 133 may extend all the way through the main body 131 , forming a through hole, such that the main body 131 of the rotatable dial is ring or annular shaped and correspondingly the spindle 140 may project through the through hole when the rotatable dial 130 is engaged with the spindle 140.

[0050] Referring back to Figure 2, in terms of how the measurement circuitry 105 uses the electrodes 101 , 102 of the capacitive sensing element 100 to make its measurements, any suitable technique may be used.

[0051] A particular technique is based on measuring what is frequently referred to as “mutual-capacitance”. With such a technique, the measurement circuitry 105 will sequentially or in parallel stimulate each of an array of transmitter (driven / drive) electrodes, for example the X electrodes 101 , that are capacitively coupled by virtue of their proximity to an array of receiver electrodes, for example the Y electrodes 102. (It should be appreciated that, in other implementations, the Y electrodes 102 may instead be the transmitting electrodes and the X electrodes 101 may instead be the receiving electrodes). The area local to and centred on the intersection of a transmitter and a receiver electrode is typically referred to as a “node” or “intersection point”. With this technique, the resulting electric field is now directly coupled from the transmitter electrode(s) 101 to each of the nearby receiver electrodes 102. Electrically conductive objects, such as the conductive electrodes 132 and / or a user’s hand gripping the rotatable dial 130, partly divert the generated electric field. An extra return path to the measurement circuitry 105 is now established via the electrically conductive region 132 and / or user and “free-space”. However, because this extra return path acts to couple the diverted field directly to the measurement circuitry 105, the amount of field coupled to the nearby receiver electrode 102 decreases. This is measured by the measurement circuitry 105 as a decrease in the “mutual-capacitance” between that particular transmitter electrode and receiver electrodes in the vicinity of electrically conductive region 132. The measurement circuitry 105 senses this change in mutual capacitance of one or more nodes. For example, if a reduction in capacitive coupling to a given Y-electrode is observed while a given X- electrode is being driven, it may be determined the electrically conductive region 132 is present in the vicinity of where the given X-electrode and given Y-electrode cross, or intersect. The decrease in the mutual capacitance at a given node is strongly dependent on the overlapping area (or projected surface) of the electrically conductive region 132 with the node. In other words, the mutual capacitance at a particular node decreases when the electrically conductive region 132 is positioned above (or overlapping with) the node, as compared to the scenario when the electrically conductive region 132 does not overlap the node.

[0052] It should be appreciated that the above technique is capable of allowing a position on the sensing surface of the capacitive sensing element 100 of the one or more electrically conductive regions 132 of the rotatable dial 130 to be determined. For example, using the mutual capacitance measurement technique, individual mutual capacitance measurements are able to be made for each of the nodes formed by the X-electrodes 101 and Y-electrodes 102 and hence those nodes that exhibit a decrease in mutual capacitance indicate a position (such as a Cartesian X-Y position) on the sensing surface of the capacitive sensing element 100.

[0053] Figures 4a and 4b schematically show the rotatable dial 130 in a first position (Figure 4a) and a second position (Figure 4b) relative to the capacitive sensing element 100. Figures 4a and 4b show the user input mechanism 1 when viewed from above, i.e. , looking at the X- Y plane in which the electrodes 101, 102 sit. Figures 4a and 4b will be understood from Figure 2; however, certain features have been omitted for clarity, such as the measurement circuitry 105 and processing circuitry 106, for example.

[0054] Figures 4a and 4b show the substrate 103 of the capacitive sensing element 100 along with the X-electrodes 101 and Y-electrodes 102 arranged in an orthogonal grid (as described in relation to Figure 2), along with the cover 108. Figures 4a and 4b further show the rotatable dial 130 overlying the cover layer 108. For ease of understanding, parts of the electrodes 101, 102 that lie under the rotatable dial 130 are shown by dashed lines. In addition, the electrically conductive regions 132 of the rotatable dial 130 are also schematically shown by shaded circles in Figures 4a and 4b.

[0055] Figure 4a shows the rotatable dial 130 arranged in a first position. In this example, the first position is one in which a line connecting the centres of the electrically conductive regions 132 is aligned with (i.e., parallel to) the X-axis of the sensing surface of the capacitive sensing element 100. As detailed above, the rotatable dial 130 is configured to rotate about the spindle 140 (not shown in Figure 4a) to allow the rotatable dial 130 to be placed into different positions relative to the capacitive sensing element 100. The first position described in Figure 4a may be referred to as the 0° position indicating the alignment with the X-axis of the capacitive sensing element 100.

[0056] Figure 4b shows the rotatable dial 130 arranged in a second position. In this example, the second position is one in which the rotatable dial 130 is rotated clockwise (with respect to Figures 4a and 4b) by approximate 45° from the first position of Figure 4a. Accordingly, the line connecting the centres of the electrically conductive regions 132 is now provided at a 45° angle to the X-axis of the sensing surface of the capacitive sensing element 100. The second position described in Figure 4b may be referred to as the 45° position indicating the displacement relative to the X-axis of the capacitive sensing element 100.

[0057] It should be appreciated that Figures 4a and 4b represent only two positions that the rotatable dial 130 may be placed in by a user and many more positions may be available. Accordingly, the present disclosure should not be considered limited to providing only two positions of the rotatable dial 130 relative to the capacitive sensing element 100.

[0058] As noted above, the processing circuitry 106 is configured to receive capacitive measurements, such as mutual-capacitance measurements, of the relevant capacitances of the electrode array 101 , 102 from the measurement circuitry 105. On the basis of the obtained measurements from the measurement circuitry 105, the processing circuitry 106 is configured to determine the position of the rotatable dial 130.

[0059] For the purposes of the following example, we consider a user input mechanism configured to operate using the mutual capacitance measurement technique. That is, the measurement circuitry 105 is configured to apply a drive signal to one or more transmitter electrodes (e.g., X-electrodes 101) and measure the mutual capacitance between a given transmitter electrode and a given receiver electrode (e.g., Y-electrodes 102). Accordingly, the measurement circuitry 105 is capable of outputting mutual capacitance measurements corresponding to each of the nodes (that is, the locations where the X-electrodes 101 cross or intersect the Y-electrodes 102) of the electrode array. Some of the nodes in Figures 4a and 4b are labelled (1 to 8) to help explain the principles of the present disclosure, and these nodes are chose in particular because these are the nodes that most closely correspond to the circular pathway that the electrically conductive regions 132 may be moved along during rotation of the rotatable dial 130. Only these nodes 1 to 8 are considered in the following description for ease of explanation.

[0060] Figure 5 is a graph depicting the mutual capacitance, C, shown on the Y-axis, for each of the nodes 1 to 8 (shown on the X-axis). Two sets of measurements are shown in Figure 5, with each set of measurements corresponding to a different scenario. For ease of explanation, each set of measurements is labelled Mi, or M2 corresponding to one of two different scenarios. For each set of measurements, there is shown an indication of the mutual capacitive coupling for each of the nodes 1 to 8 relative to a reference or baseline capacitance value (the dashed line labelled Cb). The precise value of the baseline here is not significant for the present discussion, but the baseline is considered to represent an expected mutual capacitance for each node in the absence of any external conductive objects (such as the electrically conductive regions 132),. Note that while Figure 5 shows these values as being the same for each node, this may not necessarily be the case and each node may have an individual baseline mutual capacitance.

[0061] The first set of measurements, Mi, represents the mutual capacitances of each of the sensor nodes 1 to 8 obtained when the rotatable dial 130 is in the first position (i.e., the position as shown in Figure 4a). As can be seen from the set of measurements, Mi, the mutual capacitances of each of the nodes 2 to 4 and 6 to 8 are at a value above a detection threshold (shown by the dashed line labelled Ct). The detection threshold, Ct, is set such that mutual capacitance measurements below the detection threshold signify the presence of a conductive object in the vicinity of that node, noting that in accordance with the mutual capacitance measurement technique the presence of a conductive object decreases the mutual capacitance between a driven electrode 101 and a receiver electrode 102 from an initial (baseline) value. The detection threshold, Ct, may be set having regard for the typical mutual capacitance values that one may expect to observe for the rotatable dial 130 where the electrically conductive regions 132 are capacitively coupled to the electrodes 101, 102. Thus, the processing circuitry 106 determines that no electrically conductive region 132 is present at each of the nodes 2 to 4 and 6 to 8 where the mutual capacitance measurement for these nodes is above the detection threshold, Ct. However, the mutual capacitance measurements for nodes 1 and 5 are below the detection threshold, Ct. As seen in Figure 4a, when the rotatable dial 130 is in the first position, the electrically conductive regions 132 overlap node 1 and node 5. When the rotatable dial 130 is in the first position, the electrically conductive regions 132 are located broadly above node 1 and node 5 and therefore the mutual capacitances at these nodes is relatively decreased owing to the presence of the electrically conductive regions 132.

[0062] The processing circuitry 106 is capable of determining the position of the rotatable dial 130 from the obtained set of capacitance measurements, Mi. For example, the processing circuitry 106 may be provide with a mapping that maps associated patterns or criteria in a set of obtained measurements to positions of the rotatable dial 130. For instance, a look-up table or the like may be provided which relates the first position of the rotatable dial 130 to mutual capacitance measurements of nodes 1 and 5 below the detection threshold Ct and of nodes 2 to 4 and 6 to 8 above the detection threshold Ct to the first position. In other words, when the processing circuitry 106 determines that the set of mutual capacitance measurements from the measurement circuitry 105 satisfies the criteria relating to the rotatable dial 130 being in the first position (i.e. , mutual capacitance measurements of nodes 1 and 5 below the detection threshold Ct and mutual capacitance measurements of nodes 2 to 4 and 6 to 8 above the detection threshold Ct), the processing circuitry 106 is able to determine that the rotatable dial 130 is in the first position. This may be thought of as the processing circuitry 106 identifying ‘signatures’, patterns or characteristics of the obtained measurements Mi to M2 that are associated, in advance, with certain positions of the rotatable dial 130 relative to the capacitive sensing element 100. Accordingly, the processing circuitry 106 is capable of determining the rotatable dial 130 is position corresponding to the given signature or criteria.

[0063] The second set of measurements, M2, represents the mutual capacitances of each of the sensor nodes 1 to 8 obtained when the rotatable dial 130 is in the second position (i.e., the position as shown in Figure 4b). As can be seen from the set of measurements, M2, the mutual capacitances of each of the nodes 1 , 3 to 5 and 7 to 8 are at a value above a detection threshold (shown by the dashed line labelled Ct). Thus, as with the scenario described with the first set of measurements, Mi, the processing circuitry 106 determines that no electrically conductive region 132 is present at each of the nodes 1 , 3 to 5 and 7 to 8 where the mutual capacitance measurement is above the threshold Ct. However, the mutual capacitance measurements for nodes 2 and 6 are below the detection threshold, Ct. As seen in Figure 4b, when the rotatable dial 130 is in the second position, the electrically conductive regions 132 overlap the node 2 and node 6. When the rotatable dial 130 is in the second position, the electrically conductive regions 132 are located above node 2 and node 6 and therefore the mutual capacitances at these nodes is relatively decreased owing to the presence of the electrically conductive regions 132.

[0064] When the rotatable dial 130 is the second position of Figure 4b it can be seen that the electrically conductive regions 132 overlap nodes 2 and 6 to a slightly lesser extent than the corresponding overlap of the electrically conductive regions 132 with nodes 1 and 5 when the rotatable dial 130 is in the first position of Figure 4a. Accordingly, the mutual capacitance values as measured at nodes 2 and 6 when the rotatable dial is in the second position may be greater than the mutual capacitance values as measured at nodes 1 and 5 when the rotatable dial 130 is in the first position. That is, there may be less of a decrease in the mutual capacitance value at nodes 2 and 6 when the rotatable dial 130 is in the second position owing to a lesser degree of spatial overlap of the electrically conductive regions 132 with nodes 2 and 6 as compared to the mutual capacitance value at nodes 1 and 5 when the rotatable dial 130 is in the first position. This is reflected in Figure 5 where it can be seen that the values of the mutual capacitances of nodes 2 and 6 in the second set of measurements M2 are generally greater than the values of the mutual capacitances of nodes 1 and 5 in the first set of measurements Mi.

[0065] In addition, it should also be appreciated that the electrically conductive regions 132 when the rotatable dial 130 is in the second position are relatively closer to the adjacent nodes 1, 3, 5 and 7 than to the corresponding adjacent nodes 2, 4, 6 and 8 when the rotatable dial 130 is in the first position. Thus, when the rotatable dial 130 is in the second position, the mutual capacitance measurements of the adjacent nodes may also be influenced by the presence of the electrically conductive regions 132. This is reflected in Figure 5 where it can be seen that the values of the mutual capacitances of nodes 1 , 3, 5 and 7 in the second set of measurements M2 are generally greater than the values of the mutual capacitances of nodes 2, 4, 6 and 8 in the first set of measurements Mi. In the example of Figure 5, the mutual capacitance values of nodes 1, 3, 5 and 7 are not small enough to fall below the detection threshold, Ct, but the mutual capacitance values are shown as being closer to the detection threshold, Ct.

[0066] The processing circuitry 106 is capable of determining the position of the rotatable dial 130 from the obtained capacitance measurements, M2. As above, the processing circuitry 106 may be provide with a mapping that maps associated patterns in the sets of obtained measurements to positions of the rotatable dial 130. For example, a look-up table or the like may be provided which relates the second position of the rotatable dial 130 to mutual capacitance measurements of nodes 2 and 6 below the detection threshold Ct and of nodes 1 , 3 to 5 and 7 to 8 above the detection threshold Ct to the second position. In other words, when the processing circuitry 106 determines that the set of mutual capacitance measurements from the measurement circuitry 105 satisfies the criteria relating to the rotatable dial 130 being in the second position (i.e., mutual capacitance measurements of nodes 2 and 6 below the detection threshold Ct and mutual capacitance measurements of nodes 1 , 3 to 5 and 7 to 8 above the detection threshold Ct), the processing circuitry 106 determines that the rotatable dial 130 is in the second position.

[0067] Hence, more generally, the measurement circuitry 105 is configured to obtain measurement signals from the capacitive sensing element 100 indicative of the mutual capacitances of the electrode array 101, 102, and the processing circuitry 106 is configured to determine the position of the rotatable dial 130 relative to the capacitive sensing element 100 on the basis of the measurement signals received from the measurement circuitry 105. More specifically, the processing circuitry 106 is capable of determining the positions of one or more electrically conductive regions 132 of the rotatable dial 130 relative to the capacitive sensing element 100 and from this determine the relative position of the rotatable dial 130.

[0068] It should also be appreciated that the mutual capacitance measurements in the first or second set of measurements Mi, M2 are not necessarily the same as the baseline capacitance, Cb. While the baseline capacitance, Cb, represents a mutual capacitance value in the absence of any external conductive objects (such as the electrically conductive regions 132), the baseline capacitance, Cb is typically obtained in advance (e.g., as mutual capacitance measurements performed during calibration of the user input mechanism or provided as theoretical values programmed into the processing circuitry 106 in advance). However, for an instantaneous measurement of the mutual capacitance at a given node 1 to 8, even in the absence of the electrically conductive regions 132, certain factors (e.g., such as sources of noise or the like) may cause any instantaneous mutual capacitance measurement to vary from the baseline capacitance value obtained in advance.

[0069] In addition, it should also be appreciated that in some implementations, when the user interacts with the rotatable dial 130, the mutual capacitances of the nodes adjacent the rotatable dial 130 may be weakly affected by the presence of the user’s hand and thus exhibit a slight change in the instantaneous mutual capacitance values.

[0070] While Figures 4a and 4b show two positions of the rotatable dial 130, it should be understood that the present disclosure may be extended to more than two positions of the rotatable dial 130. That is, the processing circuitry 106 may be capable of distinguishing between three, four, five etc., positions of the rotatable dial 130 based on the detected positions of the electrically conductive regions 132 of the rotatable dial 130. That is, for example, the processing circuitry 106 may be provided with a plurality of criteria (or signatures) that relate the characteristics of certain sets of measurements to one of a plurality of positions of the rotatable dial 130. For example, the first position of Figure 4a has been described as the 0° position, while the second position of Figure 4b has been described as the 45°, but there may exist a 90° position (which may display mutual capacitance measurements of nodes 3 and 7 below the detection threshold Ct and mutual capacitance measurements of nodes 1, 2, 4 to 6 and 8 above the detection threshold Ct), a 135° position (which may display mutual capacitance measurements of nodes 4 and 8 below the detection threshold Ct and mutual capacitance measurements of nodes 1 to 3 and 5 to 7 above the detection threshold Ct), etc. The processing circuitry 106 may be configured to identify a plurality of positions of the rotatable dial 130.

[0071] In addition, it should be appreciated that the principles of the present disclosure are not limited to the positions of the rotatable dial 130 in which the electrically conductive regions 132 directly overlap a node of the electrode array 101, 102. For example, one may consider a position of the rotatable dial 130 that is between the first and second positions of Figures 4a and 4b, e.g., a 22.5° position signifying a rotation of the rotatable dial 130 of 22.5° from the first position. In such an example, the surface projected by the electrically conductive regions 132 on the capacitive sensing element 100 may lie approximately between nodes 1 and 2 and nodes 5 and 6. Although the surface projected by the electrically conductive regions 132 may not overlap a node in this position of the rotatable dial 130, by virtue of the proximity of the surface projected by the electrically conductive regions 132 to the abovementioned nodes, the mutual capacitances at the nodes 1 , 2, 5 and 6 may be influenced (e.g., decreased) by the proximity of the electrically conductive regions 132. In such a case, the mutual capacitance measurements of nodes 1, 2, 5 and 6 may fall below the detection threshold Ct (although not to quite the same extent as for the first position and second position of the rotatable dial 130) while the mutual capacitance measurements of nodes 3, 4, 7 and 8 may remain above the detection threshold Ct.

[0072] While the processing circuitry 106 described above utilises a detection threshold, Ct, to determine whether a particular mutual capacitance measurement is indicative of the electrically conductive region 132 present at, or in the vicinity of, a given node 1 to 8, the processing circuitry 106 may use any suitable technique to determine the positions of the electrically conductive regions 132 from sets of capacitance measurements from the measurement circuitry 105 and, subsequently, the position of the rotatable dial 130. In some implementations, the processing circuitry 106 may compare each of the mutual capacitance measurements of the set of measurements Mi, M2 and identify whether any of the capacitance measurements corresponding to nodes 1 to 8 are greater than an average value for the set of measurements (or greater by a certain amount), and determine that the electrically conductive region 132 is detected at the corresponding nodes.

[0073] Moreover, the processing circuitry 106 in some implementations may make use of the magnitude of the mutual capacitance values of a given set of measurements to distinguish between different positions. For example, if one considers the first position of Figure 4a, and a position of the rotatable dial 130 that is rotated say 10° from the first position, it may be expected that in both positions, the mutual capacitance values at nodes 1 and 5 may fall below the detection threshold Ct. However, because the extent of overlap of the surface projected by the electrically conductive regions 132 with the nodes 1 and 5 is slightly less in the 10° position of the rotatable dial 130, the mutual capacitance values for nodes 1 and 5 may be slightly greater (i.e., have less of a decrease from the baseline value) when the rotatable dial 130 is in the 10° position. Accordingly, in such implementations, the criteria (or signature) for establishing the position of the rotatable dial 130 may be based not only on whether or not certain nodes exhibit a mutual capacitance below a detection threshold Ct, but additionally or alternatively, based on the magnitude of the mutual capacitances at each of the nodes.

[0074] While Figures 4a and 4b show an electrode array 101 , 102 comprising seven X- electrodes 101 and five Y-electrodes 102, it should be appreciated that the number of electrodes 101, 102 may be different from that shown in other implementations. In practical applications, the number of electrodes 101 , 102 may be significantly greater than that shown. Consequently, the number of electrodes 101 , 102 (and the number of nodes) adjacent to the rotatable dial 130 (include those that lie under the rotatable dial 130 as well as those that are proximate to the edge of the rotatable dial 130) may also be significantly greater. The ability of the processing circuitry 106 to accurately resolve positions of the rotatable dial 130 may be dependent in part on the density of electrodes 101 , 102 the lie under or adjacent the rotatable dial 130. A greater number of electrodes 101 , 102 (and hence also a greater number nodes) may increase the accuracy of the processing circuitry 106 to resolve the position of the rotatable dial 130, thereby allowing finer differences in the position of the rotatable dial 130 to be distinguished between.

[0075] Further, it should be appreciated that the measurement circuitry 105 may be arranged to perform capacitance measurements for all of the electrodes of the electrode array 101 , 102 or only a sub-set of the electrodes of the electrode array 101, 102. For instance, as described above in relation to Figures 4a and 4b, capacitance measurements from only a sub-set of the possible nodes may be used in order to determine the position of the rotatable dial 130. For instance, the mutual capacitances for those nodes not labelled 1 to 8 may either be measured by the measurement circuitry 105 and disregarded, or may not be measured by the measurement circuitry 105 at all (that is, in the latter case, the measurement circuitry 105 may be programmed or controlled by the processing circuitry 106 to only perform mutual capacitance measurements for nodes 1 to 8). It should be appreciated that the responsiveness of the user input mechanism 1 may be improved when measuring capacitances of only a sub-set of the electrode array 101 , 102. Figure 6 schematically shows user facing part of the user input mechanism 1 (that is absent the measurement circuitry 105 and processing circuitry 106) in cross-section along a plane through the diameter of the rotatable dial 130. Certain features of the user facing part of the user input mechanism 1 are omitted, such as electrodes 101 , 102, for convenience.

[0076] As shown in Figure 6, the rotatable dial 130 of Figures 3a and 3b is coupled to the spindle 140 which, in this implementation, is formed as a projection of the cover 108. That is to say, in this described implementation, the cover 108 includes a projection that projects from the surface of the cover 108 that forms the spindle 140. As described above, the spindle 140 is sized so as to be received in the recess portion 133 of the rotatable dial 130 and allow rotational coupling of the rotatable dial 130 to the spindle 140 such that the rotatable dial 130 is capable of rotating about the axis of the spindle 140. Although the spindle 140 is shown as being integrally formed as part of the cover 108, it should be appreciated that in other implementations, the spindle 140 may be provided a separate component attached to the cover 108 (e.g., by adhesive or the like). Alternatively, the spindle 140 may form a projection of, or be a part attached to, the substrate 103. In either case, the spindle 140 may project through the cover 108 or the cover 108 may cover additionally cover the surface of the spindle 140. Yet further alternatively, the spindle 140 may be a separate component that projects through a through hole provided in the substrate 103 and cover 108. In such implementations, the electrodes 101 , 102 of the substrate 103 may be arranged around the through hole.

[0077] In addition, Figure 6 shows, highly schematically, the user input mechanism 1 comprising a haptic feedback mechanism 150. The haptic feedback mechanism 150 may be any component suitable for generating a haptic signal (e.g., a vibration or the like) that may be perceived by a user of the user input mechanism 1. The haptic feedback mechanism 150 may be referred to as a haptic generator. For example, the haptic feedback mechanism 150 may include a piezo actuator, a linear resonant actuator, LRA, or an eccentric rotating mass, ERM motor, or similar haptic actuators. The haptic feedback mechanism 150 is arranged such that the haptic signal (e.g., vibrations) that are generated by the haptic feedback mechanism 150 are able to propagate to the main body of the rotatable dial 130 and subsequently to a user’s hand interacting with the rotatable dial 130. In the example of Figure 6, the haptic feedback mechanism 150 is positioned below the substrate 103 and coupled to a surface of the substrate 103 (specifically, the surface opposite the surface having the cover 108). The haptic feedback mechanism 150 is, in this example, indirectly coupled to the rotatable dial 130 (e.g., via the substrate 103, cover 108 and spindle 140). However, it should be appreciated that the haptic feedback mechanism 150 in other implementations may be directly coupled to the main body 131 of the rotatable dial 130. For example, the haptic feedback mechanism 150 may be embedded in the main body 131 of the rotatable dial 130.

[0078] The haptic feedback mechanism 150 is configured to provide a haptic signal (or more generally a feedback signal) under control of the processing circuitry 106. More specifically, the haptic feedback mechanism 150 is controlled to provide a feedback signal to the user on the basis of the determined position of the rotatable dial 130 relative to the capacitive sensing element 100.

[0079] Figure 7 is a flow diagram representing a method of controlling the haptic feedback mechanism 150 according to a first example.

[0080] Figure 7 begins at step S1, where the measurement circuitry 105 is controlled to obtain a set of capacitance measurements from the electrode array 101, 102. The measurement circuitry 105 may be controlled, e.g., via the processing circuitry 106 or other circuitry, to obtain the capacitance measurements periodically (e.g., when the user input mechanism 1 is provided with power) or in relation to certain triggers (e.g., such as triggers from the associated system). The measurement circuitry 105 may obtain the set of capacitance measurements (which may capacitance measurements corresponding to the entire electrode array 101 , 102 or nodes thereof, or to a subset of the electrode array 101, 102 or nodes thereof) before outputting the capacitance measurements to the processing circuitry 106, or alternatively the measurement circuitry 105 may output the capacitance measurements as they are measured. Additionally, in some implementations, the measurement circuitry 105 may be configured to obtain a plurality of capacitance measurements for a given electrode I node and determine and output an average of the capacitance measurement.

[0081] Once the obtained set of capacitance measurements at step S1 have been provided to the processing circuitry 106, at step S2, the processing circuitry 106 is configured to determine the position of the rotatable dial 130. Step S2 implements any of the described approaches above for determining the position of the rotatable dial 130.

[0082] According to the first example of controlling the haptic feedback mechanism 150, at step S3 the processing circuitry 106 is configured to determine whether the position of the rotatable dial 130 as determined in step S2 corresponds with a predetermined position of the rotatable dial 130 set in advance.

[0083] In this regard, in accordance with the first example, the processing circuitry 106 is provided with (e.g., programmed with) one or more predetermined positions of the rotatable dial 130. For example, the manufacturer of the user input mechanism 1 or of the associated system may determine that, e.g., the 0° and 90° positions of the rotatable dial 130 correspond to predetermined positions of the rotatable dial 130. The predetermined positions may be selected to correspond to certain user inputs. For example, the 0° position may be chosen to correspond to an “off” input for a given function implemented by the associated system, while the 90° position may be chosen to correspond to an “on” input for a given function implemented by the associated system, and thus in this example, when the user rotates the dial 130 from the 0° position to the 90° position, this signifies a turning on of the function implemented by the associated system. Alternatively, the 0° position may be chosen to correspond to a minimum value for a particular setting of the given function implemented by the associated system, while the 90° position may be chosen to correspond to a maximum value for a particular setting of the given function implemented by the associated system, and thus in this example, when the user rotates the dial 130 from the 0° position to the 90° position, this signifies a change in the setting of the function implemented by the associated system from a minimum to a maximum value.

[0084] At step S3, the processing circuitry 106 determines whether the determined position of the rotatable dial 130 corresponds to any of the predetermined positions set in advance. If the processing circuitry 106 determines the determined position of the rotatable dial 130 does not correspond to any of the predetermined positions set in advance, e.g., because the rotatable dial 130 is determined to be in the 45° position, then step S3 is answered in the negative (i.e., a NO at step S3) and the method proceeds back to step S1 where a new set of capacitance measurements (that is, capacitance measurements at a later time) are obtained by the measurement circuitry 105. If, however, the processing circuitry 106 determines the determined position of the rotatable dial 130 does correspond to one of the predetermined positions set in advance (e.g., the 0° or 90° positions in the above example), then step S3 is answered in the affirmative (i.e., a YES at step S3) and the method proceeds to step S4.

[0085] At step S4, the processing circuitry 106 upon determining that the position of the rotatable dial 130 corresponds with one of the predetermined positions set in advance, is configured to cause the haptic feedback mechanism 150 to output a haptic feedback signal which, as described above, is capable of being transmitted to the user gripping the rotatable dial 130 of the user input mechanism 1. Accordingly, the haptic feedback mechanism 150 is controlled to provide the haptic feedback signal in response to the determined position of the rotatable dial 130 corresponding to one or more predetermined positions of the rotatable dial 130 set in advance. The method may proceed back to step S1 after or during the implementation of step S4.

[0086] Hence, taking the above example where the 0° and 90° positions of the rotatable dial 130 are considered as the predetermined positions, the haptic feedback mechanism 150 is controlled to generate a haptic feedback signal when the rotatable dial 130 is determined to be in the 0° position or the 90° position. In this example, no haptic feedback is provided when the rotatable dial 130 is determined to be in a position other than the 0° or 90° positions. Accordingly, when the haptic feedback signal is provided to the user, the user can interpret the haptic feedback signal as indicating the predetermined position has been reached. Taking the examples described above, the haptic feedback signal may be provided to indicate to the user that e.g., the given function implemented by the associated system has been turned on I off or that the particular setting for the function implemented by the associated system is at its minimum I maximum value.

[0087] Hence, more broadly, in accordance with the first example of controlling the haptic feedback mechanism 150, the processing circuitry 106 is configured to cause the haptic feedback mechanism 150 to provide the haptic feedback signal in response to the determined position of the rotatable dial 130 corresponding to one or more predetermined positions set in advance.

[0088] In terms of the form of the haptic feedback signal, for example such as the frequency or amplitude of the vibrations, the haptic feedback signal is not particularly limited, but is set such that the user is able to perceive the haptic feedback signal. In some implementations, the haptic feedback signal is provided at a constant amplitude and / or constant frequency. In other implementations, the haptic feedback signal is provided where at least one of the amplitude and / or frequency is varied over the duration at which the haptic feedback signal is output, for example to provide a ‘pulse’ or the like of haptic feedback. In yet further implementations, the haptic feedback signal may be configured to provide haptic feedback that mimics a certain effect. For instance, in some mechanical-based rotatable dials of a conventional configuration, a mechanical stop may be used to prevent a dial from rotating past a certain point. The haptic feedback signal may be generated to mimic the feel of a mechanical dial hitting such a mechanical stop (although it should be appreciated that in the case of the present example, the rotation of the rotatable dial 130 is not limited by a physical mechanical stop, and thus may rotate past the associated position). In other examples, some mechanical-based rotatable dials of a conventional configuration include protrusions and notches which produce a haptic sensation when the mechanical rotatable dial is rotated such that a protrusion engages with a notch. The haptic feedback signal may be generated to mimic the feel of a mechanical dial engaging with such notches. Hence, the form of the haptic feedback signal is not particularly limited, and any suitable haptic feedback signal may be implemented by the haptic feedback mechanism 150.

[0089] In some implementations, the haptic feedback signal may be controlled to be different depending on the predetermined position that the rotatable dial 130 is determined to be in. For example, the haptic feedback signal may be generated at a first frequency when the rotatable dial 130 is determined to be in the 0° position and may be generated at a second frequency when the rotatable dial 130 is determined to be in the 90° position. The user may be able to distinguish between the different haptic feedback signals and subsequently attribute a different meaning to the signals - for example, the haptic signal at the first frequency may be associated with turning off the function of the associated system and the haptic signal at the second frequency may be associated with turning on the function of the associated system. More generally, the processing circuitry 106 is configured to cause the haptic feedback mechanism 150 to provide the haptic feedback signal having at least one characteristic (e.g., frequency and amplitude) that is dependent on the determined position of the rotatable dial 130.

[0090] The haptic feedback signal may be generated and output for a predetermined time. That is, when the processing circuitry 106 initially determines that the position of the rotatable dial 130 matches a given predetermined position, the haptic feedback mechanism 150 is controlled to output the haptic feedback signal for a predetermined time. This predetermined time may correspond to an arbitrary time set in advance, e.g., a one or two second time period, or the time period may correspond to a particular effect that is to be mimicked (such as hitting a stop or engaging a notch).

[0091] With respect to Figure 7, not shown is the step of the processing circuitry 106 outputting a signal to the associated system indicative of the position of the rotatable dial 130. Depending on the implementation at hand, the processing circuitry 106 may output a signal to the associated system indicative of the position of the rotatable dial 130 either in conjunction with step S2 or in conjunction with step S4. That is, in some implementations, the processing circuitry 106 outputs a signal to the associated system indicative of the position of the rotatable dial 130 regardless of whether the rotatable dial 130 is in one of the predetermined positions or another position. The associated system may then be configured to interpret the position of the rotatable dial 130 and determine whether this position corresponds to a particular input for the function implemented by the associated system. In other implementations, the processing circuitry 106 outputs a signal to the associated system indicative of the position of the rotatable dial 130 only when the rotatable dial 130 is determined to be in one of the predetermined positions. The associated system may then be configured to use the output from the processing circuitry 106 as an associated input for the function implemented by the associated system.

[0092] As described above, in some implementations, the predetermined positions of the rotatable dial 130 are set in advance by the manufacturer of the user input mechanism 1 or the associated system. However, in other implementations, the predetermined positions may be customised by a user of the user input mechanism. Figure 8 shows a modification to the method of Figure 7 in which, at step S5, the processing circuitry 106 receives an indication of user-defined predetermined positions for the rotatable dial 130. In this regard, the user is capable of interacting with an appropriate user interface (e.g., provided on the associated system or provided on a remote device, such as smartphone or personal computer, communicatively coupled to the processing circuitry 106) to provide the user-defined predetermined positions for the rotatable dial 130. For instance, using the above examples, when interacting with the user interface, the user may be able to select, e.g., the 45° position as corresponding to an “on” input for the function performed by the associated system while keeping the 90° position as corresponding to an “off” input for the function performed by the associated system. Alternatively, the user may set the 0°, 45° and 90° positions of the rotatable dial 130 as predetermined positions. In this example, the user would expect to receive a haptic feedback signal when the processing circuitry 106 determines that the rotatable dial 130 is in any one of the 0°, 45° and 90° positions.

[0093] Step S5 is shown as proceeding to either of steps S1 or S3. In most implementations, the user will set the user-defined predetermined positions for the rotatable dial 130 in advance of using the user input mechanism 1. However, the processing circuitry 106 may not necessarily be provided with the user-defined predetermined positions in advance of obtaining the capacitance measurements at step S1, but instead may be provided with the user-defined predetermined positions when performing the determination at step S3.

[0094] The above describes a first example where the processing circuitry 106 is configured to cause the haptic feedback mechanism 150 to provide haptic feedback signals when the position of the rotatable dial 130 is determined to correspond with one of one or more predetermined positions set in advance. However, in accordance with the principles of the present disclosure, this may not be the only way in which the processing circuitry 106 provides a haptic feedback signal to the user.

[0095] Figure 9 is a flow diagram representing a method of controlling the haptic feedback mechanism 150 according to a second example.

[0096] Figure 9 starts at step S1, where the measurement circuitry 105 is controlled to obtain a set of capacitance measurements from the electrode array 101, 102. Step S1 of Figure 9 is, in effect, identical to step S1 of Figure 7.

[0097] Once the obtained set of capacitance measurements at step S1 have been provided to the processing circuitry 106, Figure 9 differs from Figure 7 in that the method proceeds to step S12.

[0098] At step S12, the processing circuitry 106 is configured to receive a second set of capacitance measurements from the electrode array 101 , 102. Step S12 is the same as step S1 except the second set of capacitance measurements are obtained at a different point in time as compared to the set of capacitance measurements of step S1. For example, if the measurement circuitry 105 is configured to obtain the capacitance measurements of the electrode array 101 , 102 periodically, for example at 0.1 ms intervals, then the capacitance measurements obtained at steps S1 and S12 are separated in time by 0.1 ms.

[0099] According to the second example of controlling the haptic feedback mechanism 150, at step S13 the processing circuitry 106 is configured to determine whether the rotatable dial 130 is currently being moved (rotated) by the user. In this regard, the processing circuitry 106 is configured to determine a position of the rotatable dial 130 based on the set of capacitance measurements obtained at step S1 and to determine a second position of the rotatable dial 130 based on the second set of capacitance measurements obtained at step S12. For example, any of the techniques described above for determining the position of the rotatable dial 130 from a set of capacitance measurements may be implemented at step S13. Based on the position of the rotatable dial 130 obtained from the set of capacitance measurements obtained at step S1 and the second position of the rotatable dial 130 obtained from the second set of capacitance measurements obtained at step S12, the processing circuitry 106 is configured to determine whether there is any change in the position of the rotatable dial 130. For example, the processing circuitry 106 may determine that the rotatable dial 130 is in the 0° position based on the set of capacitance measurements received from step S1, and determines that the rotatable dial 130 is in the 22.5° position based on the second set of capacitance measurements received from step S12. Accordingly, the processing circuitry 106 is capable of determining there has been a change in position (in this case of 22.5°) and from this determines that the rotatable dial 130 is currently being moved.

[0100] Accordingly, at step S13, when it is determined that the rotatable dial 130 is currently being moved (rotated) based on a change in the determined position of the rotatable dial 130 determined at two different (and in some implementations consecutive) times, the processing circuitry 106 is capable of determining when the rotatable dial 130 is being moved by the user. In response to step S13 being answered in the affirmative (i.e., YES at step S13), the method proceeds to step S14 where the processing circuitry 106 is further configured to cause the haptic feedback mechanism 150 to provide the haptic feedback signal in response to determining the rotatable dial 130 is being moved by the user. That is to say, the processing circuitry 106 is configured to determine when the rotatable dial 130 is being moved by the user based on determining a change in the position of the rotatable dial 130 from an initial position (or a positioned determined earlier in time).

[0101] In this example, the haptic feedback provided at step S14 is provided to indicate to the user that the rotatable dial 130 is being moved. That is to say, the user is provided with a haptic feedback that indicates to the user that the user input mechanism 1 recognises that the rotatable dial 130 is being rotated. This may provide the user with some degree of confidence that the rotatable dial 130 is functioning correctly. In some implementations, the haptic feedback signal provided at step S14 may be provided so as to mimic the resistance that a user might feel if they were to actuate a mechanical rotatable dial (e.g., such as a resistance experienced by turning a potentiometer or other mechanical arrangement coupled to the rotatable dial).

[0102] As seen in Figure 9, if at step S13 it is determined by the processing circuitry 106 that the rotatable dial 103 is not currently being moved (i.e., a NO at step S13), then the method returns to step S12. In this case, the set of capacitance measurements obtained at step S1 are disregarded, while the second set of capacitance measurements obtained previously at step S12 now form the first set of capacitance measurements and a new second set of capacitance measurements are obtained at step S12. It should be appreciated that the processing circuitry 106 may determine that the rotatable dial 130 is not being moved if the determined position of the rotatable dial 130 from the set of capacitance measurements at step S1 and the determined position of the rotatable dial 130 from the second set of capacitance measurements at step S12 is the same.

[0103] In one implementation, the haptic feedback at step S14 is output while the processing circuitry 106 determines that the rotatable dial 130 is being moved. That is, once the processing circuitry 106 determines the rotatable dial 130 is being moved at step S13, until the processing circuitry 106 subsequently determines that the rotatable dial 130 is no longer being moved, the processing circuitry 106 is configured to cause the haptic feedback mechanism 150 to output the haptic feedback signal. This is shown in Figure 9 where, after step S14, the method proceeds to step S12 and, as described above, the set of capacitance measurements obtained at step S1 are disregarded, while the second set of capacitance measurements obtained previously at step S12 now form the first set of capacitance measurements and a new second set of capacitance measurements are obtained at step S12.

[0104] In some implementations, the haptic feedback signal has at least one characteristic (for example, frequency and amplitude) that is dependent on at least one of: the amount of change in the position of the rotatable dial 130 from a first position and the rate of movement of the rotatable dial 130. For instance, the amplitude of the haptic feedback signal may be set to be dependent on the degree of change of position of the rotatable dial 130 or the rate of movement of the rotatable dial. If, for example, the processing circuitry 106 determines the position of the rotatable dial 130 from the first set of capacitance measurements at step S1 is the 0° position and if the position of the rotatable dial 130 from the second set of capacitance measurements at step S12 is the 45° position, the haptic feedback signal may be set to have a greater amplitude than instances where the processing circuitry 106 determines the position of the rotatable dial 130 from the second set of capacitance measurements at step S12 is the 22.5° position. In this example, the rate of movement (rotation) can be derived from determining the change in position over the known time (e.g., 0.1ms) between obtaining the set of capacitance measurements at step S1 and the second step of capacitance measurements at step S12. In other examples, the haptic feedback signal may be varied based on the total amount of change in the position of the rotatable dial 130. For example, the processing circuitry 106 may be configured to cause the haptic feedback mechanism 150 to output a haptic signal of a first strength (amplitude) when the position of the rotatable dial 130 is determined to move from the 0° position to the 22.5° and subsequently (i.e., with the same movement action) if the rotatable dial 130 is continued to be rotated to the 45° position, the processing circuitry 106 may be configured to cause the haptic feedback mechanism 150 to output a haptic signal of a second strength (amplitude), and so on for continued rotation to a 67.5° position and so on. Hence, in this example, a characteristic of the haptic signal varies based on the total amount of movement of the rotatable dial 130 from an initial position with the same movement / rotation of the rotatable dial 130.

[0105] Hence, described above are two examples where the processing circuitry 106 is configured to cause the haptic feedback mechanism 150 to output a haptic feedback signal based on the determined position of the rotatable dial 130. In Figure 7, the haptic feedback signal is output depending upon the position of the rotatable dial 130 being determined to correspond to a predetermined position for the rotatable dial 130 set in advance. In Figure 9, the haptic feedback signal is output depending upon detected movement of the rotatable dial 130 (based on determining the position of the rotatable dial 130). However, it should be appreciated that the two techniques may be combined to provide haptic feedback both when the position of the rotatable dial 130 is determined to correspond to a predetermined position for the rotatable dial 130 set in advance and when there is detected movement of the rotatable dial 130.

[0106] Figure 10 is a flow diagram representing a method of controlling the haptic feedback mechanism 150 according to a third example, in which the techniques of the first example (Figure 7) and of the second example (Figure 9) are combined. Figure 10 will be understood from Figures 7 and 9 and similar steps are labelled with the same reference signs. For conciseness, the below focuses on the interaction of these steps.

[0107] Figure 10 starts at step S1, where the measurement circuitry 105 is controlled to obtain a set of capacitance measurements from the electrode array 101, 102 in a similar manner to Figures 7 and 9. Once the obtained set of capacitance measurements at step S1 have been provided to the processing circuitry 106, Figure 10 proceeds to step S2 and S3 as described in Figure 7. If at step S3, the processing circuitry 106 determines the determined position of the rotatable dial 130 does correspond to one of the predetermined positions set in advance, then step S3 is answered in the affirmative (i.e. , a YES at step S3) and the method proceeds to step S4 as described in Figure 7.

[0108] However, if the processing circuitry 106 determines the determined position of the rotatable dial 130 does not correspond to one of the predetermined positions set in advance, i.e., a NO at step S3, then the method proceeds to step S12.

[0109] As in Figure 9, at step S12, the measurement circuitry 105 obtains a second set of capacitance measurements of the electrode array. The method proceeds to step S3’ which is, in effect, the same as step S3 except the processing circuitry 106 is configured to determine whether the position of the rotatable dial 130 as determined using the second set of capacitance measurements obtained at step S12 corresponds to a predetermined position set in advance. (Note for clarity reasons, an equivalent step to S2 for the second set of capacitance measurements is omitted from Figure 10.)

[0110] If it is determined that the determined position of the rotatable dial 130 as determined from the second set of capacitance measurements of step S12 does correspond to one of the predetermined positions set in advance, i.e., a YES at step S3’, then the method proceeds to step S4.

[0111] If it is determined that the determined position of the rotatable dial 130 as determined from the second set of capacitance measurements of step S12 does not correspond to one of the predetermined positions set in advance, i.e., a NO at step S3’, then the method subsequently proceeds as described in Figure 9. That is, the method proceeds via step S3’ to step S13. If it is determined the rotatable dial 130 is being moved at step S13, the method proceeds to step S14.

[0112] Additionally, although not shown in Figure 10, the haptic feedback signals in steps S4 and S14 are configured to be different. That is to say, the processing circuitry 106 is configured to cause the haptic feedback mechanism 150 to provide a first haptic feedback signal (at step S4) when the determined position of the rotatable dial 130 corresponds to one or more predetermined positions set in advance, and a second feedback signal (at step S14) in response to determining a movement of the rotatable dial 130, wherein the first haptic feedback signal differs from the second haptic feedback signal (e.g., in terms of the frequency and / or amplitude, and optionally the variation of amplitude and / or frequency with time). Hence, in accordance with the above, the present disclosure describes a user input mechanism 1 comprising a capacitive sensing element 100 and a rotatable dial 130 moveably mounted with respect to the capacitive sensing element 100 and comprising one or more electrically conductive regions 132 capable of capacitively coupling to the capacitive sensing element 100. Processing circuitry 106 of the user input mechanism 1 is configured to determine the position of the rotatable dial 130 relative to the capacitive sensing element 100, and control a haptic feedback mechanism 150 to provide a haptic feedback signal to the user on the basis of the determined position of the rotatable dial 130 relative to the capacitive sensing element 100.

[0113] Accordingly, the user input mechanism 1 of the present disclosure provides a rotatable dial 130 that offers a physical component for a user of the user input mechanism 1 to interact with (e.g., grip and rotate) to provide a user input to an associated system, but does so in a way that is compatible with the flexibility afforded by use of capacitive sensor elements 100. Moreover, the rotatable dial 130 is provided in a coupled arrangement, either directly or indirectly, with a haptic feedback mechanism 150 that is able to provide haptic feedback to a user to inform the user of their interaction with the rotatable dial 130 (i.e., to simulate friction or other effects experienced during rotation of the dial 130 and / or when a particular position has been reached). By providing the haptic feedback mechanism 150 along with the rotatable dial 130, the user can be provided with an experience that is similar to a conventional rotatable dial 130.

[0114] Figure 3a and 3b show an example of the rotatable dial 130 in which first and second conductive regions 132 are provided at positions diametrically opposed to one another relative to the diameter of the rotatable dial 130. Put another way, when viewed along the axis of rotation of the rotatable dial 130, the centre of the electrically conductive regions 132 lie on a line of symmetry of the rotatable dial 130. As a result, it should be appreciated that, for example, the processing circuitry 106 may be unable to differentiate between the rotatable dial 130 being in the 0° position (e.g., the first position in Figure 3a) or the 180° position (e.g., the position of the rotatable dial 130 in Figure 3a rotated by 180°). In some implementations, it may be desired to distinguish between the positions of the rotatable dial 130 between 180° to 360° from the positions between 0° to 90°.

[0115] Figure 11a schematically shows a further implementation of a rotatable dial 130’ which is configured to allow the processing circuitry 106 to distinguish positions of the rotatable dial 130’ between 180° to 360° from the positions of the rotatable dial 130’ between 0° to 90° according to a first example. Figure 11a shows a view from the lower side of the rotatable dial 130’ (where the lower side is the side that is to be positioned closest to the cover 108 in Figure 1), and is similar to and will be understood from Figure 3b. In Figure 11a, the rotatable dial 130’ comprises a main body 131 and a recess 133 that are substantially similar to the corresponding components in Figure 3b. The rotatable dial 130’ similarly includes two electrically conductive regions 132; however, in this implementation, the second electrically conductive region 132b is provided at a different spatial position to the equivalent conductive region 132 in Figure 3b. In this regard, it can be seen from Figure 11a that the centre of one electrically conductive region (the first electrically conductive region 132a) lines along a line of symmetry S that passes through the axis of rotation of the rotatable dial 130’. However, the centre of the other electrically conductive region (the second electrically conductive region 132b) is shown at a position that is offset from the line of symmetry S.

[0116] With reference to Figure 4a, when the rotatable dial 130’ is in the first position (the 0° position), the first electrically conductive region 132a overlaps with node 1 of the capacitive sensing element 100 in a similar manner to rotatable dial 130 as seen in Figure 4a. However, the second electrically conductive region 132b instead overlaps with node 6 of the capacitive sensing element 100. Accordingly, in this implementation, the processing circuitry 106 may be configured to recognise that the first position (the 0° position) of the rotatable dial 130’ corresponds to a set of mutual capacitance measurements in which the mutual capacitance measurements of nodes 1 and 6 are below the detection threshold Ct and the mutual capacitance measurements of nodes 2 to 5 and 7 to 8 are above the detection threshold Ct.

[0117] If one now considers the rotation of the rotatable dial 130’ by 180° about the axis of rotation I spindle 140, it can be understood that the first electrically conductive region 132a now overlaps with node 5 of the capacitive sensing element 100, while the second electrically conductive region 132b now overlaps with node 2 of the capacitive sensing element 100. Accordingly, the processing circuitry 106 may be configured to recognise that the 180° position of the rotatable dial 130’ corresponds to a set of mutual capacitance measurements in which the mutual capacitance measurements of nodes 2 and 5 are below the detection threshold Ct and the mutual capacitance measurements of nodes 1 , 3 to 4 and 6 to 8 are above the detection threshold Ct.

[0118] Hence, it can be seen from the above that the processing circuitry 106 is capable of distinguishing between the 0° position and the 180° of rotatable dial 130’ by virtue of the offset of the second electrically conductive region 132b. It should be appreciated that while Figure 11a shows one example of how the second electrically conductive region 132b may be offset form the line of symmetry S, in other implementations, the position of the second electrically conductive region 132b may be different.

[0119] Figure 11b schematically shows a further implementation of a rotatable dial 130” which is configured to allow the processing circuitry 106 to distinguish positions of the rotatable dial 130” between 180° to 360° from the positions of the rotatable dial 130’ between 0° to 90° according to a second example. Figure 11b shows a view from the lower side of the rotatable dial 130” (where the lower side is the side that is to be positioned closest to the cover 108 in Figure 1), and is similar to and will be understood from Figure 3b.

[0120] In Figure 11b, the rotatable dial 130” comprises a main body 131 and a recess 133 that are substantially similar to the corresponding components in Figure 3b. The rotatable dial 130” similarly includes two electrically conductive regions 132; however, in this implementation, the second electrically conductive region 132b’ has a different shape (and more particularly, a different shape of the surface projected onto the cover 108 / capacitive sensing element 100) as compared to the equivalent conductive region 132 in Figure 3b. In this regard, it can be seen from Figure 11b that instead of defining a circular area I surface, the second electrically conductive region 132b’ instead defines an arc-shaped area I surface

[0121] With reference to Figure 4a, when the rotatable dial 130” is in the first position (the 0° position), the first electrically conductive region 132a overlaps with node 1 of the capacitive sensing element 100 in a similar manner to rotatable dial 130 as seen in Figure 4a. However, the second electrically conductive region 132b’ instead now overlaps with nodes 4, 5 and 6 of the capacitive sensing element 100. Accordingly, in this implementation, the processing circuitry 106 may be configured to recognise that the first position (the 0° position) of the rotatable dial 130” corresponds to a set of mutual capacitance measurements in which the mutual capacitance measurements of nodes 1 and 4 to 6 are below the detection threshold Ct and the mutual capacitance measurements of nodes 2 to 3 and 7 to 8 are above the detection threshold Ct.

[0122] If one now considers the rotation of the rotatable dial 130” by 180° about the axis of rotation I spindle 140, it can be understood that the first electrically conductive region 132a now overlaps with node 5 of the capacitive sensing element 100, while the second electrically conductive region 132b’ now overlaps with nodes 1 , 2 and 8 of the capacitive sensing element 100. Accordingly, the processing circuitry 106 may be configured to recognise that the 180° position of the rotatable dial 130” corresponds to a set of mutual capacitance measurements in which the mutual capacitance measurements of nodes 1 , 2, 5 and 8 are below the detection threshold Ct and the mutual capacitance measurements of nodes 3 to 4 and 6 to 7 above the detection threshold Ct.

[0123] Hence, it can be seen from the above that the processing circuitry 106 is capable of distinguishing between the 0° position and the 180° of rotatable dial 130” by virtue of the shape of the second electrically conductive region 132b’. It should be appreciated that while Figure 11b shows one example of a different shape of the second electrically conductive region 132b’, in other implementations, the shape of the second electrically conductive region 132b’ may be different from that shown.

[0124] Thus, more generally, when there is a plurality of electrically conductive regions 132, at least two of the electrically conductive regions 132 are either arranged such that surfaces of the at least two electrically conductive regions 132 projected onto a surface of the capacitive sensing element 100 are different or such that the centre of one of the at least two electrically conductive regions 132b is disposed offset from a line of symmetry S of the shape of the rotatable dial 130’ projected onto the surface of the capacitive sensing element 100 passing through the centre of the other of the at least two electrically conductive regions 132a.

[0125] In other implementations, the rotatable dial 130 may comprise a single electrically conductive region 132 (for example, electrically conductive region 132a of Figures 11a or 11b). Providing a single electrically conductive region 132 in the rotatable dial 130 would allow the processing circuitry 106 to be capable of distinguishing between the 0° position and the 180° of rotatable dial 130, but such arrangements may be prone to error (for example, based on how the user holds the rotatable dial 130 and the degree of capacitive coupling to the rotatable dial 130).

[0126] In the described implementations above, the user input mechanism 1 comprises a rotatable dial 130. The rotatable dial 130 is an example of a moveable component and it should be appreciated that, in other implementations, the user input mechanism 1 may comprise alternative moveable components to the rotatable dial 130. For example in some implementations, the moveable component may comprise a slider configured to move in a linear fashion along the surface of the capacitive sensing element 100. In addition, the shape of the moveable component may be any suitable shape. For example, the rotatable dial 130 described above is cylindrical, but in other implementations the cross-section of the cylinder may be elliptical or the rotatable dial 130 may have a cuboidal shape. In some implementations, the shape of the moveable component is adapted for ergonomic comfort for a user interacting with the moveable component and may additionally take account of the type of movement that the moveable component undergoes (e.g., rotation or linear translation).

[0127] Moreover, in the above described implementations, the rotatable dial 130 is coupled to the capacitive sensing element 100 / cover 108 via a spindle 140. However, it should be understood that any suitable coupling mechanism may be used to moveably couple the moveable component to the capacitive sensing element 100 or cover 108. For example, in some implementations, an enclosed track having an inverted T-shaped cross-section (when viewed along the direction of travel of the moveable component) may be provided in the cover 108 and / or capacitive sensing element 100 and the moveable component may comprise an equivalent inverted T-shaped projection which fits within, and is adapted to slide along, the track. In some implementations, the coupling mechanism may form a part of the cover 108 / sensing element 100 (including, for example, a through hole for receiving the spindle 140). However, in other implementations, the coupling mechanism may comprise an adhesive or the like whereby e.g., a spindle 140 coupled to the rotatable dial 130 is able to be adhered onto the surface of the cover 108 / capacitive sensing element 100. Such a coupling mechanism may allow for retrofitting or adaptable positioning of the moveable component to an already existing capacitive sensing element 100. Consequently, the processing circuitry 106 may adapted to undergo a calibration process to recognise the one or more predetermined positions of the moveable component.

[0128] It has been described above that the user input mechanism 1 comprises a haptic feedback mechanism 150 for providing a haptic feedback signal to a user of the user input mechanism under certain conditions as described above. However, it should be appreciated that in other implementations, other feedback mechanisms may be employed. For example, in some implementations, the feedback mechanism may alternatively, or additionally, comprise an audio feedback mechanism, such as a speaker. The audio feedback mechanism may be controlled to provide an audio signal when e.g., one of a plurality of predetermined positions are reached (e.g., such as a ‘click’ sound) or when movement of the moveable component is detected (e.g., such as a ‘whirring’ or ‘grinding’ sound). In other implementations, a visual feedback mechanism may additionally or alternatively be employed, such as a display (for example, underlying a transparent capacitive sensing element 100 and cover 108) or one or more LED lights. In such cases the visual feedback mechanism may be controlled to provide a visual signal when e.g., one of a plurality of predetermined positions are reached (e.g., such as a ‘flash’ or display of a solid colour) or when movement of the moveable component is detected (e.g., such as a ‘dim glow’ or a changing colour). Thus, more generally, it should be appreciated that any suitable feedback mechanism may be employed in the user input mechanism 1 to communicate feedback to the user regarding their operation of the moveable component.

[0129] As described above, the user input mechanism 1 comprises a capacitive sensing element 100 that comprises a plurality of electrodes 101, 102, at least a part of which are positioned below or adjacent the moveable component. In some implementations, such as those described above, the capacitive sensing element 100 may be provided exclusively for sensing the position of the moveable component. However, in other implementations, the capacitive sensing element 100 may extend around the moveable component and additionally be configured to detect other objects in regions surrounding the moveable component. For example, the capacitive sensing element 100 may comprise a touch- sensitive region in which the user input mechanism 1 is configured to detect one or more user touches (e.g., a user’s finger(s) and / or a stylus held by the user). The moveable component may thus be provided in a region adjacent the touch-sensitive region. In this case, the measurement circuity 105 may be configured to obtain capacitance measurements relating to the electrodes 101, 102 around the moveable component in addition to the electrodes 101, 102 forming the touch-sensitive region. The processing circuitry 106 may be configured to determine both the movement of the moveable component (e.g., from analysing a sub-set of capacitance measurements and / or identifying characteristic signatures in the set of measurements) and the one or more touches (e.g., from signals surpassing a threshold at locations in the touch-sensitive region). Similarly, when the processing circuitry 106 detects a touch in the touch-sensitive region, the processing circuitry 106 can output a signal to the associated system indicating the corresponding user input. In such implementations, combining the touch-sensitive region and the moveable component may simplify manufacture (in particular of the associated system) and reduce the overall user input mechanism footprint compared to separately providing a capacitive sensing element 100 forming the touch-sensitive region and a capacitive sensing element for detecting the position of the moveable component. It should also be appreciated that in a similar manner, multiple moveable components may be provided on the same capacitive sensing element 100 and the processing circuitry 106 may be adapted to sense the positions of each of the moveable components.

[0130] Thus there has been described a user input mechanism for providing a signal indicative of a user input to a system communicatively coupled to the user input mechanism. The user input mechanism includes: a capacitive sensing element configured to sense changes in capacitance at one or more locations of the capacitive sensing element; a moveable component moveably mounted with respect to the capacitive sensing element and configured to be moveable by a user of the user input mechanism, wherein the moveable component is provided with one or more electrically conductive regions capable of capacitively coupling to the capacitive sensing element; control circuitry configured to receive signals from the capacitive sensing element and to determine the position of the moveable component relative to the capacitive sensing element; and a feedback mechanism arranged to provide feedback to a user of the user input mechanism. The control circuitry is configured to control the feedback mechanism to provide a feedback signal to the user on the basis of the determined position of the moveable component relative to the capacitive sensing element. Also described is a system and a method. Further particular and preferred aspects of the present invention are set out in the accompanying independent and dependent claims. It will be appreciated that features of the dependent claims may be combined with features of the independent claims in combinations other than those explicitly set out in the claims.

Claims

CLAIMS1. A user input mechanism for providing a signal indicative of a user input to a system communicatively coupled to the user input mechanism, wherein the user input mechanism comprises: a capacitive sensing element configured to sense changes in capacitance at one or more locations of the capacitive sensing element; a moveable component moveably mounted with respect to the capacitive sensing element and configured to be moveable by a user of the user input mechanism, wherein the moveable component is provided with one or more electrically conductive regions capable of capacitively coupling to the capacitive sensing element; control circuitry configured to receive signals from the capacitive sensing element and to determine the position of the moveable component relative to the capacitive sensing element; and a feedback mechanism arranged to provide feedback to a user of the user input mechanism, wherein the control circuitry is configured to control the feedback mechanism to provide a feedback signal to the user on the basis of the determined position of the moveable component relative to the capacitive sensing element.

2. The user input mechanism of claim 1, wherein the control circuitry is configured to cause the feedback mechanism to provide the feedback signal in response to the determined position of the moveable component corresponding to one or more predetermined positions set in advance.

3. The user input mechanism of claim 2, wherein the control circuitry is configured to cause the feedback mechanism to provide the feedback signal having at least one characteristic that is dependent on the determined position of the moveable component.

4. The user input mechanism of claim 2 or 3, wherein the feedback mechanism is configured to provide the feedback signal for a predetermined time period.

5. The user input mechanism of any one of claims 2 to 4, wherein the control circuitry is configured such that the user of the user input mechanism is able to customise the one or more predetermined positions.

6. The user input mechanism of claim 1, wherein the control circuitry is configured to determine when the moveable component is being moved by the user, and is further configured to cause the feedback mechanism to provide the feedback signal in response to determining the moveable component is being moved by the user.

7. The user input mechanism of claim 6, wherein the control circuitry is configured to determine when the moveable component is being moved by the user based on determining a change in the position of the moveable component from an initial position.

8. The user input mechanism of claims 6 or 7, wherein the control circuitry is configured to cause the feedback signal to be output while the moveable component is being moved by the user.

9. The user input mechanism of any one of claims 6 to 8, wherein the control circuitry is configured to cause the feedback mechanism to provide the feedback signal having at least one characteristic that is dependent on at least one of: the amount of change in the position of the moveable component from a first position and the rate of movement of the moveable component.

10. The user input mechanism of any one of the preceding claims, wherein the feedback signal includes a first feedback signal and a second feedback signal, and wherein the control circuitry is configured to cause the feedback mechanism to provide the first feedback signal in response to determining the moveable component is being moved by the user and to provide the second feedback signal when the determined position of the moveable component corresponds to one or more predetermined positions set in advance, wherein the first feedback signal differs from the second feedback signal.

11. The user input mechanism of any one of the preceding claims, wherein the feedback mechanism is a haptic feedback generator and wherein the feedback signal is a haptic feedback signal.

12. The user input mechanism of claim 11 , wherein the haptic feedback generator is coupled to the moveable component.

13. The user input mechanism of any one of the preceding claims, wherein the moveable component is arranged to couple to a spindle fixedly mounted relative to the capacitivesensing element and the moveable component is capable of rotating about the spindle by a user of the user input mechanism.

14. The user input mechanism of claim 13, when dependent on any one of claims 11 or 12, wherein the haptic feedback generator is coupled to the spindle.

15. The user input mechanism of any one of the preceding claims, wherein the moveable component is arranged such that, when there is a plurality of electrically conductive regions, the electrically conductive regions are arranged with a non-conductive material disposed therebetween.

16. The user input mechanism of any one of the preceding claims, wherein the moveable component is arranged such that, when there is a plurality of electrically conductive regions, at least two of the electrically conductive regions are either arranged such that surfaces of the at least two electrically conductive regions projected onto a surface of the capacitive sensing element are different and / or such that the centre of one of the at least two electrically conductive regions is disposed offset from a line of symmetry of the shape of the moveable component projected onto the surface of the capacitive sensing element passing through the centre of the other of the at least two electrically conductive regions.

17. The user input mechanism of any one of the preceding claims, wherein the capacitive sensing element comprises a plurality of electrodes arranged in a grid.

18. A system comprising the user input mechanism of any one of the preceding claims, wherein the system is configured to receive the determined position of the moveable component from the processing circuitry of the user input mechanism and to perform a function responsive to the received determined position of the moveable component.

19. A method for providing feedback to a user of a user input mechanism for providing a signal indicative of a user input to a system communicatively coupled to the user input mechanism, wherein the user input mechanism comprises a capacitive sensing element to sense changes in capacitance at one or more locations of the capacitive sensing element, a moveable component moveably mounted with respect to the capacitive sensing element and configured to be moveable by a user of the user input mechanism, wherein the moveable component is provided with one or more electrically conductive regions capable of capacitively coupling to the capacitive sensing element, control circuitry configured to receivesignals from the capacitive sensing element and to determine the position of the moveable component relative to the capacitive sensing element; and a feedback mechanism arranged to provide feedback to a user of the user input mechanism, wherein the method comprises: determining a position of the moveable component relative to the capacitive sensing element; and providing a feedback signal to the user on the basis of the determined position of the moveable component relative to the capacitive sensing element.

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