Display system having a physical actuator

Abstract

A display system has a casing accommodating a controller and a display, and further includes a physical actuator mounted on the display and an actuator controller, the actuator controller including a magnetic field sensor and the display being between the actuator and the magnetic field sensor. The physical actuator includes a magnetic field source and is configured to modify presence and / or magnitude of a magnetic field of the magnetic field source during its actuation, the magnetic field sensor being configured to detect the presence and / or magnitude of the magnetic field.

Description

[0001] Display System having a Physical Actuator

[0002] Field of the Invention

[0003] The present invention relates to a display systems that include one or more physical actuators positioned on the display surface of the display system. Preferred embodiments are directed to touchscreen display systems.

[0004] Background to the Invention

[0005] Touchscreen display systems are becoming increasingly popular for a large number of applications and fields. One of the key attractions is their flexibility and intuitiveness. A touchscreen display system can be used for multiple purposes, simply by changing what is displayed so as to represent some different control actuator arrangement, or change the subject that the control actuators are controlling. For many applications, having a virtual button, dial or other actuator displayed on screen is sufficient to enable a user to interact with the control system.

[0006] However, there are instances when a virtual control actuator is undesirable - for example when the touchscreen is to be used in the dark (such as in some professional audio-visual environments) or without the user being able to view the touchscreen (automotive applications, for example where a user should not take their eyes off the road) or where the user may not be able to interact with a capacitive touchscreen (because they are wearing gloves, for example). There are other instances that may impact the ability to use a touchscreen such as marine / naval systems (water can make a capacitive touchscreen inoperative or unreliable) and high stress level environments, such as aviation or medical applications, where the cognitive demand is proven to be lower with something tactile objects rather than a pure touch based controls.

[0007] Various attempts have been made to provide physical actuators such as knobs, buttons, faders and the like that are fixed upon the display surface. Some of these use wiring from actuators to a controller / processor. However, it is undesirable for such physical actuators to use their own wiring because this then has to pass over the display surface and reduces the usable area of the display surface for display and / or touchscreen applications. Some physical actuators have instead attempted to interact with the display system, for example using the capacitive sensor lines of the display system to communicate user interactions detected from the physical actuator. However, latency and precision are often problems with such approaches and placement then also becomes dependent on the configuration and positioning of the sensor lines.

[0008] Statement of Invention

[0009] According to an aspect of the present invention, there is provided a touchscreen display system having a casing accommodating a controller and a touchscreen display, the touchscreen display system further including a physical actuator mounted on the touchscreen display and an actuator controller, the actuator controller including a magnetic field sensor and the touchscreen display being between the actuator and the magnetic field sensor, wherein the physical actuator includes a magnetic field source and is configured to modify presence and / or magnitude of a magnetic field of the magnetic field source during its actuation, the magnetic field sensor being configured to detect the presence and / or magnitude of the magnetic field.

[0010] Preferably, the magnetic field sensor comprises a hall effect sensor.

[0011] The magnetic field sensor may be configured to communicate the presence and / or magnitude of the magnetic field to the actuator controller, the actuator controller determining a state or a change of state of the physical actuator from the presence and / or magnitude of the magnetic field.

[0012] The physical actuator may comprise a knob, the knob being rotatable relative to the touchscreen display, the magnetic field source comprising a magnet configured to move and / or change magnitude of the magnetic field presented to the magnetic field sensor upon rotation of the knob. The knob may rotate about a shaft, the magnet being mounted at an end of the shaft proximate the touchscreen display and having magnetic poles oriented substantially perpendicular to a rotation axis of the shaft whereby rotation of the knob about the shaft rotates the magnetic poles about the rotation axis.

[0013] At least a part of the physical actuator may, as a secondary actuation operation, be configured to be moveable towards the touchscreen display upon application of a force to the respective part, wherein the magnetic field source is connected to the respective part and is configured to move towards the touchscreen display when the respective part of the actuator is moved by application of the force.

[0014] The physical actuator may comprise a slider, the slider being moveable along a predetermined path on the touchscreen display, the magnetic field source comprising a magnet configured to move and / or change magnitude of the magnetic field presented to the magnetic field sensor as the slider is moved along the path.

[0015] The physical actuator may comprise a push button, the push button having a part that is moveable towards the touchscreen display, the magnetic field source comprising a magnet configured to move and / or change magnitude of the magnetic field presented to the magnetic field sensor as the part is moved towards the touchscreen display.

[0016] At least part of the physical actuator may be electrically conductive, the touchscreen display being configured to monitor the electrically conductive part of the physical actuator for a change in capacitance corresponding to a touch of the electrically conductive part by a user.

[0017] The electrically conductive part of the physical actuator may comprise an exterior part of the physical actuator to be touched by the user. The exterior part may be electrically connected to the magnetic field source, the touchscreen display being configured to monitor the touchscreen display adjacent the magnetic field source for a change in capacitance corresponding to a touch of the electrically conductive part by a user. The exterior part may be electrically connected to a body part of the actuator that is adjacent the touchscreen display being configured to monitor the touchscreen display adjacent the body part for a change in capacitance corresponding to a touch of the electrically conductive part by a user.

[0018] The touchscreen display system may further comprise a mount for adhering to the touchscreen display, the physical actuator and mount having mating parts to mount the physical actuator in the mount.

[0019] The touchscreen display may include an integral mount, the physical actuator and mount having mating parts to mount the physical actuator in the mount.

[0020] At least part of the physical actuator may be frangible and configured to break without breakage of the mount or display. The breaking of the frangible part preferably permits removal of the physical actuator from the mount. The frangible part is preferably arranged to break upon application of a force that exceeds a predetermined magnitude and / or a force that has a direction substantially different to a force applied during normal operation of the physical actuator.

[0021] The magnetic field sensor may be substantially adjacent a magnetic shield.

[0022] The magnetic field sensor may be in the casing or external to the casing.

[0023] According to another aspect of the present invention, there is provided a display system having a casing accommodating a controller and a display, the display system further including a physical actuator mounted on the display and an actuator controller, the actuator controller including a magnetic field sensor and the display being between the actuator and the magnetic field sensor, wherein the physical actuator includes a magnetic field source and is configured to modify presence and / or magnitude of a magnetic field of the magnetic field source during its actuation, the magnetic field sensor being configured to detect the presence and / or magnitude of the magnetic field.

[0024] Embodiments of the present invention seek to provide high precision control input devices for use within the active display / touch area of an LCD, TFT or other display device so graphics and text can be located immediately adjacent to the control input device, and preferably also the area behind the control input device. Precision in this context covers parameters such as: resolution of movement of actuator, smoothness of tactile feel, and reliable detection of actuation.

[0025] To provide this precision and to solve the problem of tactile feedback through operational control objects, embodiments are directed to physical control input devices that are usable with conventional capacitive touch screen or other similar display devices. Advantageously, these embodiments not only offer tactile feedback but that also can have a control input actuation detected without needing to detect the touch of a user. This feature means that the control input devices can be used by gloved individuals in medical environments, for example.

[0026] Embodiments are directed to control input devices that operate when mounted on capacitive touchscreen devices but do not need the human body grounding that would arise from a normal touch.

[0027] In some embodiments, the control input devices have an electrically conducting surface enables detection of a user's touch due to change in capacitance (note that this is not a requirement for general operation of the physical actuator, simply to extend it to also be able to detect a touch). Examples of the physical actuators are set out below.

[0028] Brief description of the Drawings

[0029] An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0030] Figure 1 is a schematic diagram of a display system according to an embodiment;

[0031] Figures 2a and 2b are a schematic diagrams of a display system including a physical knob according to an embodiment;

[0032] Figures 3a-c are schematic diagrams illustrating aspects of the knob of Figure 2a and 2b having a second, push, actuation operation;

[0033] Figure 4 is a schematic diagram of features of a mount according to an embodiment;

[0034] Figure 5 is a schematic diagram of features of a mount according to another embodiment; Figure 6 is a schematic diagram of features of a touch detection mechanism for use in embodiments of the present invention; and,

[0035] Figure 7 is a schematic diagram of aspects of a display system according to another embodiment.

[0036] Detailed Description

[0037] Figure 1 is a schematic diagram of a display system according to an embodiment. The display system has a casing 40 accommodating a controller 60 and a display 50. The display system further includes a physical actuator 10 mounted on the display 50 and an actuator controller 20 in (or in some embodiments on) the casing 40. The actuator controller 20 includes a magnetic field sensor, preferably including one or more hall effect sensors. The display 50 lies between the physical actuator 10 and the magnetic field sensor. The physical actuator 10 includes a magnetic field source such as a magnet and is configured to modify presence and / or magnitude and / or direction of a magnetic field during its actuation. The magnetic field sensor is configured to detect the presence and / or magnitude and / or direction of the magnetic field.

[0038] The actuator controller 20 may be separate and connectable to the controller 60 of the display system. The presence and / or magnitude of the magnetic field over time can be used to determine operations performed at the physical actuator 10. In the following embodiments, a touchscreen display system is described. However, other than the embodiments using the touchscreen display system features, it will be appreciated that non-touch display types could also be used.

[0039] In the case of a rotary knob as illustrated in Figures 2a and 2b below, the physical actuator is mounted on the touchscreen display 50 such that the knob 10 can be rotated about an axis (A) substantially perpendicular to the touchscreen display 50. Figure 2a shows the knob 10 with elements that (in this embodiment) rotate being shaded the same. The elements are labelled and shaded separately in Figure 2b. The parts that rotate as the knob is rotated are a cap 11, a shaft 12 and a magnet 15. The magnet 15 has poles extending substantially parallel to the touchscreen display surface 50. The magnet 15 is configured to rotate about the same axis (A) as the knob and in this embodiment is coupled to a shaft of the knob 12 so that as the user rotates the knob, the magnet rotates. In this embodiment, a sensor, preferably a hall effect sensor 21, which is part of or connected to the actuator controller 20, is positioned opposite the magnet 15 such that it detects changes in the magnetic field as the magnet 15 (and therefore the knob) rotates. A body 14 mounts the knob to the display surface 50.

[0040] The knob in this embodiment also illustrates various optional features including a bearing 13 to aid the rotation, a detent spring 18 to provide feedback as the knob is turned and an O- ring or other sealing / damper element 19 to aid sealing / fit. Features relating to optional embodiments that are discussed in more detail below are also shown. These include a mount 30 and a bayonet connector 17. A further optional element is shown in which the shaft 12 engages a resiliently flexible member 16 which enables the shaft (and therefore the knob and magnet to move towards the display surface.

[0041] Also illustrated in Figure 2a (by way of example only) are components of the touchscreen 50 which include a cover lens 51, a PCAP (projected capacitive touch) layer 52, a display 53 (such as an LCD panel) and a chassis 54 (which may be sheet metal). In this embodiment, the actuator 10 is secured to the touchscreen by a layer of UV adhesive 55. The magnet 15, actuator controller 20 and sensors 21 may be selected based on desired application and configuration. For example, the magnet 15 may be a 4 pole magnet with N / S / N / S poles in quadrants alternating about the axis so as to increase the frequency in which a change from N to S is detected by the sensor as the magnet rotates (it of course could be subdivided into smaller or larger sectors to suit the implementation). Similarly, the sensor may have multiple sensing nodes aligned and distributed about the axis so as to enable a greater granularity of detection as well as enable speed and direction detection (speed being detectable by rate in which consecutive sensing nodes detect a particular change in magnetic field whilst direction being detectable based on a clockwise or anticlockwise order in what the change is detected).

[0042] Optionally, the physical actuator may include a push button, as illustrated in Figures 3a, 3b and 3c. In this embodiment, the actuator such as a knob shown in Figure 2 is configured to also enable a push force (B) to move the knob and therefore the magnet towards the display screen. Figure 3a shows the knob without presence of the push force and Figure 3b with the presence of a push force B. The lines towards the top of the knob are present to illustrate relative position of the knob in the two drawings.

[0043] This movement causes the magnetic field strength detected by the sensor to increase. In this embodiment, a threshold is set in the actuator controller 20 to trigger a push event detection when the field strength exceeds the threshold. In some embodiments this may be a calibrated threshold that is determined from testing field strength as the magnet travels the available distance towards the display. In other embodiments, this may be a preconfigured value that has been determined in the factory or similar based on knowledge of the push travel distance, sensitivity of the sensor and also the strength of the magnet.

[0044] In the embodiment of Figures 3a and 3b, the push button mechanical functionality is provided via a dome switch 16 (shown in Figure 3c) that sits around a shoulder or end of the shaft. The dome switch 16 provides sprung resistance as the knob is depressed and also provides the spring return force once the knob is no longer being pressed. As in the previous embodiments, no electrical connections or capacitive sensing is needed, the motion of the magnet 15 towards the sensor / actuation controller 20 is sufficient for an increase in field strength and a press event to be detected by the actuator controller 20. This in turn can be communicated to a processor 60 or other computing component to respond to the event.

[0045] While physical actuators may be mounted to the touchscreen display in many ways, including directly glueing onto the screen, in a preferred embodiment shown in Figure 4, a mount 30 is provided that is attached to the touchscreen display 50 and the physical actuator then engages mounting points 31 in the mount so as to secure it in place.

[0046] In the embodiment of Figure 4, the mounting points 31 are in the form of a bayonet fitting with the mount 30 and physical actuator having complementary male 17 and female 31 bayonet parts that engage and lock the physical actuator 10 in place in the mount 30. A sprung part or resilient part may optionally be provided to lock the bayonet fitting in place once the parts engage.

[0047] Optionally, a bespoke tool may be used during installation of the physical actuator such that it can only be turned in the mount so as to engage (whether by means of a bayonet fitting or otherwise) using the bespoke tool. For example, the bespoke tool may fit around a particular part of the physical actuator that is difficult to reach / turn by hand. Such arrangements are advantageous as it prevents accidental disengagement of the physical actuator from the mount.

[0048] In one embodiment, preferably at least part of a body of the physical actuator (such as the part 17) that secures it in the mount is frangible upon application of a force F that exceeds predetermined tolerances or which is applied in a direction outside that expected in normal operation of the physical actuator. The presence of a frangible part of the body means that excessive or unusual force breaks the body / physical actuator rather than the touchscreen display or the mount. In such an arrangement, the broken physical actuator can be removed from the mount and a replacement installed. In the illustrated embodiment, part of the body of the physical actuator that forms the bayonet fitting is made frangible by weakening the body from reduced wall thickness (or it may be made of a more brittle material that the remainder of the body and the mount).

[0049] It will be appreciated that other mechanisms than bayonet mounts such a screw fitting, spring lock and the like could be used.

[0050] In one embodiment, as illustrated in Figure 5, the mount 30 is integrally formed or molded with a surface of the touchscreen display 50 and is then part of the touchscreen display once assembled. In this embodiment, no glueing of the mount to the display screen is needed, the robustness of the mounting of the actuator is increased and ingress of liquid or dirt at the join between the screen and the mount where it would otherwise have been glued is avoided.

[0051] It will be appreciated that other physical actuators such as sliders and buttons can be implemented in a similar way to the knob described above, with a magnet or multiple magnets being moved along a path or otherwise having properties changed and corresponding sensors behind the display screen positioned to detect the movement or property change and thereby able to infer the movement or other actuation.

[0052] The physical actuator 10 may be configured to produce a coded signal by its movement or actuation. Such a coded signal may be used for communicating multiple events to sensor, with the actuator controller decoding the signal and conveying the event(s) to the processor or other downstream computing system. Alternatively, multiple different magnets may be used, each for communicating a single different event to a corresponding sensor.

[0053] In addition, or alternatively to push functions, embodiments may enable sensing of touch events on the actuator 10. In such embodiments, portions of the physical actuator may be conductive. A change in capacitance at that part can be used to infer the presence of a touch event by the user. In the embodiment of Figure 6, at least part of the body of the knob is electrically conductive and is electrically connected to the magnet 15 by the path shown (by way of illustration) in the bold line from the hand 100. The capacitance presented by the magnet is monitored by the touchscreen via the touchscreen controller. Changes in capacitance are detected and communicated by the touchscreen controller to the processor which may also receive event signals from the actuator controller on other operations of the knob. The events can then be used to make a state / state change determination of the physical actuator (for example, whether a touch event is present due to change in ground potential, whether it is being turned and if so in which direction, whether it is also in a pressed state etc.). The processor or other downstream computing system can then cause appropriate action to the system, such as changing of graphics displayed on the touchscreen, communication with an external system, etc. It will be appreciated that current / past states of the actuator as well as other functionality of the system such as touchscreen events, actuation of other controllers, etc. can also be taken into account by the processor. Instead of using the magnet as the entity that is monitored for a change of capacitance, part of the body or mount that engages the touchscreen may similarly be used - this has the advantage that it is not being moved and so the capacitance changes are more likely to be due to touch events. However, the use of the magnet is advantageous as it typically would in any event be a metal / electrical conductor.

[0054] The inventor of the present application has identified that positioning a magnetic field sensor such as a hall effect sensor within the casing of a touchscreen display system or on the back side of the casing enables a physical actuator such as a turnable knob, a button or slider to be mounted on (the other side of) the display screen to the sensor and use magnetic fields to communicate its position and / or state to the magnetic field sensor within or through the casing. Such arrangements are, advantageously, wireless and do not need the actuator to interact with the touchscreen, its sensing wires or with the touchscreen controller.

[0055] Current implementations have shown that the gap between the actuator and the magnetic field sensor can be up to around 4mm while retaining good detection resolution.

[0056] In one embodiment, the magnetic field sensor 21 is positioned substantially in front of, and preferably adjacent to, a magnetic shield 41. Preferably, the magnetic shield 41 is part of the casing 40. By positioning the magnetic field sensor 21 substantially in front of and preferably adjacent to a magnetic shield 41, it has been identified that the detection resolution of the magnetic field sensor 21 can be improved and in turn enables distance to the actuator 10 to be increased and / or better detection resolution of the magnetic field sensor 21. The magnetic shield 41 may be the back shielding of the touchscreen display system, for example. Where necessary, the depth of the casing may be increased to accommodate the magnetic field sensor and associated controller or the components within the casing may be rearranged so as to accommodate it.

[0057] In tests, it has been identified that positioning a hall effect sensor adjacent the back shielding of the casing of a touchscreen display system extends the maximum detection range of the sensor by approximately 30% because it directs the magnetic field towards the Hall effect sensor.

[0058] In another embodiment, the magnetic field sensor 21 may be positioned externally of the casing 40 (for example as a retro-fit component added to the back of existing touchscreen display devices). In this arrangement, the shield 41 may be between the magnetic field sensor and the physical actuator 10.

[0059] Optionally, a concentrator or other approach may be used to focus or otherwise improve performance of the sensor.

[0060] In tests, a round magnet was used in the actuator with 5 mm diameter and 2mm thickness generating 299 milliTesla field at its surface.

[0061] Materials between the magnet and the sensor were the touch display screen and its associated printed circuits which in total were around 2mm thick. In some of the tests, a 0.3 mm thick sheet metal backshield 30 x 130 mm was positioned behind the sensor which was a hall effect sensor. Results:

[0062] The surface area of the back shield is much larger than the magnet. These dimension proportions enabled as much as possible of stray magnetic fields from the actuator to be collected and increased detection range of the sensor.

[0063] As explained above, it will be appreciated that embodiments may also be applied to systems having non-touch display screens.

[0064] Optional embodiments of the invention can be understood as including the parts, elements and features referred to or indicated herein, individually or collectively, in any or all combinations of two or more of the parts, elements or features, and wherein specific integers are mentioned herein which have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

[0065] Although illustrated embodiments of the present invention have been described, it should be understood that various changes, substitutions, and alterations can be made by one of ordinary skill in the art without departing from the present invention which is defined by the recitations in the claims below and equivalents thereof.

[0066] This application claims priority from GB 2314586.5, the content of which is incorporated by reference.

Claims

Claims1. A touchscreen display system having a casing accommodating a controller and a touchscreen display, the touchscreen display system further including a physical actuator mounted on the touchscreen display and an actuator controller, the actuator controller including a magnetic field sensor and the touchscreen display being between the actuator and the magnetic field sensor, wherein the physical actuator includes a magnetic field source and is configured to modify presence and / or magnitude of a magnetic field of the magnetic field source during its actuation, the magnetic field sensor being configured to detect the presence and / or magnitude of the magnetic field.

2. The touchscreen display system of claim 1, wherein the magnetic field sensor comprises a hall effect sensor.

3. The touchscreen display system of clam 1 or 2, wherein the magnetic field sensor is configured to communicate the presence and / or magnitude of the magnetic field to the actuator controller, the actuator controller determining a state or a change of state of the physical actuator from the presence and / or magnitude of the magnetic field.

4. The touchscreen display system of claim 1, 2 or 3, wherein the physical actuator comprises a knob, the knob being rotatable relative to the touchscreen display, the magnetic field source comprising a magnet configured to move and / or change magnitude of the magnetic field presented to the magnetic field sensor upon rotation of the knob.

5. The touchscreen display system of claim 4, wherein the knob rotates about a shaft, the magnet being mounted at an end of the shaft proximate the touchscreen display and having magnetic poles oriented substantially perpendicular to a rotation axis of the shaft whereby rotation of the knob about the shaft rotates the magnetic poles about the rotation axis.

6. The touchscreen display system of any preceding claim, wherein at least a part of the physical actuator is configured to be moveable towards the touchscreen display upon application of a force to the respective part, wherein the magnetic field source is connected to the respective part and is configured to move towards the touchscreen display when the respective part of the actuator is moved by application of the force.

7. The touchscreen display system of any preceding claim, wherein the physical actuator comprises a slider, the slider being moveable along a predetermined path on the touchscreen display, the magnetic field source comprising a magnet configured to move and / or change magnitude of the magnetic field presented to the magnetic field sensor as the slider is moved along the path.

8. The touchscreen display system of any preceding claim, wherein the physical actuator comprises a push button, the push button having a part that is moveable towards the touchscreen display, the magnetic field source comprising a magnet configured to move and / or change magnitude of the magnetic field presented to the magnetic field sensor as the part is moved towards the touchscreen display.

9. The touchscreen display system of any preceding claim, wherein at least part of the physical actuator is electrically conductive, the touchscreen display being configured to monitor the electrically conductive part of the physical actuator for a change in capacitance corresponding to a touch of the electrically conductive part by a user.

10. The touchscreen display system of claim 9, wherein the electrically conductive part of the physical actuator comprises an exterior part of the physical actuator to be touched by the user.

11. The touchscreen display system of claim 10, wherein the exterior part is electrically connected to the magnetic field source, the touchscreen display being configured to monitor the touchscreen display adjacent the magnetic field source for a change in capacitance corresponding to a touch of the electrically conductive part by a user.

12. The touchscreen display system of claim 10, wherein the exterior part is electrically connected to a body part of the actuator that is adjacent the touchscreen display being configured to monitor the touchscreen display adjacent the body part for a change in capacitance corresponding to a touch of the electrically conductive part by a user.

13. The touchscreen display system of any preceding claim, further comprising a mount for adhering to the touchscreen display, the physical actuator and mount having mating parts to mount the physical actuator in the mount.

14. The touchscreen display system of any of claims 1 to 12, wherein the touchscreen display includes an integral mount, the physical actuator and mount having mating parts to mount the physical actuator in the mount.

15. The touchscreen display system of claim 13 or 14, wherein at least part of the physical actuator is frangible and is configured to break and permit removal of the physical actuator from the mount upon application of a force that exceeds a predetermined magnitude and / or has a direction substantially different to a force applied during normal operation of the physical actuator.

16. The touchscreen display system of any preceding claim, wherein the magnetic field sensor is substantially adjacent a magnetic shield.

17. The touchscreen display system of any preceding claim, wherein the magnetic field sensor is in the casing.

18. The touchscreen display system of any preceding claim, wherein the magnetic field sensor is external to the casing.

19. A display system having a casing accommodating a controller and a display, the display system further including a physical actuator mounted on the display and an actuator controller, the actuator controller including a magnetic field sensor and the display being between the actuator and the magnetic field sensor, wherein the physical actuator includes a magnetic field source and is configured to modify presence and / or magnitude of a magnetic field of the magnetic field source during its actuation, the magnetic field sensor being configured to detect the presence and / or magnitude of the magnetic field.

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