Control input device for capacitive touch screen

Abstract

A control input device for a capacitive touch screen, a system including the control input device, and a capacitive touch screen are disclosed. The control input device includes: a base for mounting the device in place on a capacitive touch screen; an actuator supported by the base and electrically insulated from the base, the actuator having an electrically conductive surface and further comprising: an electrode in contact with or adjacent to the capacitive touch screen when the base is in position; a circuit between the electrode and the conductive surface, the conductive surface having a surface area selected such that the conductive surface provides infinite or near infinite capacitive coupling such that the capacitive coupling between the electrode and the capacitive touch screen can be detected by a controller of the capacitive touch screen, the electrodes are configured to experience a change corresponding to a state of the actuator, and a controller of the touch screen is capable of determining the state of the actuator according to the change of the electrodes.

Description

Technical Field

[0001] The present invention relates to control input devices for capacitive touch screens that are particularly useful for complex interfaces and interfaces that a user can navigate solely or primarily by touch. Background Art

[0002] Capacitive touch screens are an increasingly common input method for software and computer-based systems in many industries and applications. They offer versatility, simplicity of operation, and compactness.

[0003] However, for complex operations such as audio mixing, there are many problems with using touch screen controls.

[0004] First, manual operation of a touchscreen does not provide the precision of traditional controls such as potentiometers, shaft encoders, linear faders, and electromechanical switches.

[0005] Second, the lack of tactile feedback provided by touchscreens is detrimental to the development of motor memory, which is essential for users to concentrate on completing complex tasks when interacting with a control interface.

[0006] There are tactile switches for touch screens. Typically, they include an actuator (such as a switch or button) and a sensing electrode. The actuator has a user contact surface that is electrically connected to the electrode. When the user presses the actuator, the circuit is completed and connects the electrode to the touching finger (representing ground), thereby generating an input in the receiving software. However, the switch itself can only provide limited functionality.

[0007] Another area where touch screens are expected to be used is in medical and industrial applications. However, there is a further complication here: such environments may require users to wear protective gloves, etc. In such cases, conventional touch screens may not correctly or at all recognize the touch of a person wearing gloves.

[0008] Therefore, it is desirable to provide other input mechanisms for touch screens as a means of interaction for complex operations (such as audio mixing), especially mechanisms that can provide precise control and tactile feedback. Summary of the invention

[0009] According to an aspect of the present invention, there is provided a control input device for a capacitive touch screen, comprising:

[0010] a base for mounting the device in place on the capacitive touch screen;

[0011] An actuator supported by and electrically insulated from the base, the actuator having a conductive surface and further comprising:

[0012] an electrode that is in contact with or adjacent to the capacitive touch screen when the base is in place; and

[0013] Circuit, between an electrode and a conductive surface,

[0014] The conductive surface has a surface area selected such that the conductive surface provides infinite or nearly infinite capacitive coupling so that the capacitive coupling between the electrode and the capacitive touch screen can be detected by a controller of the capacitive touch screen,

[0015] Wherein, in use, the electrodes are configured to undergo changes corresponding to the state of the actuator, and a controller of the touch screen is able to determine the state of the actuator based on the changes in the electrodes.

[0016] The actuator may include a switch connection, wherein the switch is actuated by the actuator.

[0017] Actuation of the switch may be configured to modify the electrical circuit between the electrode and the conductive surface, thereby causing a change.

[0018] The change may include disconnection of the conductive surface from the electrode.

[0019] The electrical circuit may include capacitive coupling between the electrode and the conductive surface.

[0020] The circuit may include an optoelectronic component configured to modify the circuit based on the received optical signal.

[0021] The actuator may be configured to control light exposure from the optoelectronic components of the touch screen when the control input device is mounted on the capacitive touch screen.

[0022] During actuation the electrodes may change position relative to the touch screen surface, and the change in position of the electrodes can be detected by the touch screen controller.

[0023] The control input device may also include a first plurality of electrodes at respective predetermined positions on the capacitive touch screen, the control input device having a second plurality of electrodes positioned in a predetermined pattern, wherein actuation of the control input device causes a change in the relative positioning of the first plurality of electrodes and the second plurality of electrodes and a corresponding change in capacitance at the first plurality of electrodes, and the corresponding change in capacitance at the first plurality of electrodes can be detected by a controller of the touch screen.

[0024] The control input device may be part of a system that includes a lookup table that maps capacitance detected at the first plurality of electrodes to the position of the actuator. This may also be provided in other ways so that the controller of the touch screen can access it.

[0025] According to another aspect of the present invention, a capacitive touch screen is provided, the capacitive touch screen comprising:

[0026] Controller; and

[0027] The control input device as described herein, wherein the base of the control input device is mounted on a capacitive touch screen, and the electrodes of the control input device are configured to present capacitance at one or more predetermined positions on the touch screen.

[0028] Therein, the controller is configured to scan one or more predetermined locations to obtain the presented capacitance.

[0029] The controller may include control logic for determining a state of the actuator based on the presented capacitance.

[0030] The controller may include control logic for determining the state of the actuator based on the value of the presented capacitance.

[0031] The controller may include control logic for determining a state of the actuator based on the location of the presented capacitance on the touch screen.

[0032] The circuit may be simply a permanent electrical connection between the conductive surface and the electrode (such as in the slider / fader and knob examples below), it may be a switch connection (where the switch is actuated by actuation of an actuator, such as in the push button example below), or some other circuit. The circuit may alternatively or additionally include capacitive coupling between the electrode and the conductive surface.

[0033] Embodiments of the present invention seek to provide a high precision control input device for use within an active display / touch area of ​​an LCD, TFT or other display device, such that graphics and text can be located in close proximity to the control input device, and preferably also in an area behind the control input device. Precision in this context encompasses parameters such as resolution of movement of the actuator, smoothness of tactile feel, and reliable detection of actuation.

[0034] In order to provide this precision and solve the problem of tactile feedback by manipulating control objects, embodiments are directed to physical control input devices that can be used with conventional capacitive touch screen devices. Advantageously, these embodiments not only provide tactile feedback, but can also have control input actuation detected in the absence of human body capacitance (through skin touch). This feature means that the control input device can be used by people wearing gloves in medical environments.

[0035] Embodiments relate to control input devices that can operate when mounted on a capacitive touch screen device, but do not require human body grounding caused by normal touch. Each control input device has a conductive surface having an area that allows it to provide infinite capacitive coupling (or close to infinity so that it has an effect that is considered infinite). It will be understood that in an electrical sense, infinity is equivalent to the value of the ambient / surrounding ground potential. Therefore, the conductive surface provides a virtual grounding effect. This virtual grounding effect means that it can replace human body touch (although it will still be effective in the presence of human body touch). Due to the presence of virtual grounding, different types of control input devices can be implemented that use capacitive touch screens to signal actuation (but do not require human body touch required by prior art methods).

[0036] Examples of controlling input devices are as follows.

[0037] In one embodiment, the virtual ground is electrically connected to an electrode through a circuit, the electrode changes position during actuation of the control input device (such as sliding of a slider, turning of a knob), and the change in position can be detected by the touch screen.

[0038] The use of virtual ground means that the control input device will work with or without human body grounding, so its field of use has been greatly expanded, including medical applications and industrial applications, in which the ground contact of the hand is inhibited / blocked by protective gloves, etc. Since the control input device uses a virtual ground instead of grounding via human touch, this means that, advantageously, the conductive surface is not necessarily a surface that the user can touch when actuating the device. For example, the following push button example uses a transparent (and possibly non-conductive) material for the main button area so that the image on the touch screen, etc. is not blocked. This method enables the control input device to have a contact area made of non-conductive material and still be operable. A specific benefit of the conductive surface being different from the surface touched by the user is that it makes the control operation and the resulting signal less dependent on external factors. Although it is described as a surface, it will be understood that the surface does not need to be exposed-the package will have a surface.

[0039] The respective electrodes of the control input device present a capacitive charge which can be detected by the sensor wiring of the touch screen and in turn enables actuation or position (where applicable) of the control input device to be detected and detected by the existing controller of the capacitive touch screen.

[0040] Advantageously, the electrode is configured to undergo a change corresponding to the state of the actuator. For example, the actuator may include a switch connection, and the switch of the connection may modify the circuit between the electrode and the conductive surface. This may be used to disconnect the conductive surface, change the capacitance presented, or perhaps where there are multiple electrodes or the electrode has multiple parts, it may change which electrode part presents the capacitance.

[0041] In addition to switches, other changes may include changes in capacitive coupling. The circuit may, for example, include an adjustable capacitor or other electronic component that can be set, adjusted, or otherwise controlled by operation of an actuator or based on an external source / signal. For example, in the case of a variable capacitor, during certain operation of the actuator, the electrodes of the capacitor may be physically moved.

[0042] In terms of the location of the presented capacitance on the moving touch screen, or by actually measuring the presented capacitance through the touch screen's controller or an external analog-to-digital controller or a dedicated touch screen controller operating in parallel with the touch screen controller of a conventional touch screen, the change in capacitance can be used to increase the resolution of the touch screen's controller's detection of the presented capacitance and / or it can also be detected separately.

[0043] In another advantageous embodiment (which may be combined with the above embodiment), the circuit may include an optoelectronic component such as a photodiode or other photodetector. In such an embodiment, the touch screen may be used to communicate with the optoelectronic component and cause a change in the circuit (and thus a change in the capacitance presented by the electrode). As will be understood, as an alternative or in addition to signaling, the circuit may also be powered via the optoelectronic component.

[0044] In one embodiment, the display can be used as a constant light source. A shutter disc is coupled to the actuator so that the shutter disc causes an increase or decrease in the light beam toward a photoelectric component (e.g., a photodiode), which then switches on or off the coupling of the electrode to a virtual ground. Multiple electrodes can be used to increase the bus width. In another embodiment, light from the screen can be directed to a photovoltaic component in a circuit, which in turn is used to power a controller that converts a relatively high frequency signal (e.g., >120 Hz) of a mechanical orthogonal encoder coupled to the action of the actuator (e.g., such as rotation) into a semi-absolute 1-n code that can be communicated from an electrode (such as the electrodes described below) using a virtual ground coupling.

[0045] In another advantageous embodiment that can be selectively combined with the features of the above-described embodiments, a first plurality of electrodes can be fixed at respective predetermined positions on the capacitive touch screen, wherein the control input device has a second plurality of electrodes positioned in a predetermined pattern, which at least partially aligns with the first plurality of electrodes and moves out of the position aligned with the first plurality of electrodes during actuation. For example, in the case of a rotating controller, the pattern moves in and out of the aligned position so that the touch screen controller can detect the capacitance presented by the second plurality of electrodes on the control input device via the first plurality of electrodes. The capacitance values ​​presented at the respective first electrodes depend on the relative position of the pattern, which changes as the controller rotates. A lookup table or the like can be provided, and the capacitance values ​​are mapped to the provided positions or positions learned through training and stored in the lookup table. When the touch screen controller needs to determine the position of the control input device, it obtains the capacitance at the first electrode and uses the lookup table to obtain the position of the control input device.

[0046] It will also be appreciated that the pattern of second electrodes connected to the conductive surface may also be modified by methods such as those described above. Thus, different patterns of active second electrodes may be presented depending on the mode of controlling the input device set by the actuator and / or circuitry.

[0047] Modulation of signaling by the touchscreen controller may optionally be used to improve coupling and signal detection between the control input device and the touchscreen controller, thereby improving recognition of control actuations.

[0048] Embodiments enable capacitive touch screens to detect actuation without human conduction. This allows actuation to be performed using a covered hand (e.g., a surgical glove) or via a non-conductive object. In at least selected embodiments, electrodes are physically moved relative to the touch screen surface so that differences in capacitance created by non-human components that have been optimized for capacitive effects can be seen.

[0049] The infinite capacitance of a conducting sphere of radius r is:

[0050] In order for this equation to hold, the sphere must be isolated in the universe, so the electric potential of the surrounding field drops by Φ in every direction. 1 / R. Anywhere close to the sphere, the presence of a ground or some ground plane will violate this condition and affect the capacitance. In this case, an expression for the capacitance can be found. Based on the above formula, the embodiment approximates the capacitance to infinity (ground potential).

[0051] In a preferred embodiment, the capacitance of the conductive surface is at least on the order of magnitude of the mutual capacitance of the sensor grid of the touch screen. For example, in some touch screens, this value can be about 0.7 pF. This can be converted to the surface area of ​​the sphere (using the equation above), and the minimum surface area required for the conductive surface can then be calculated. For a typical capacitive touch screen tested, the radius of the sphere is about 5 mm, so the minimum area is about 200 mm 2 However, it will be appreciated that the capacitance and signal-to-noise ratio when reading depends on factors such as the sensitivity of the touch screen controller, the configuration of the sensor grid, etc. Therefore, the minimum area may be smaller, depending on the properties of the touch screen used.

[0052] Embodiments apply this principle by incorporating a conductive surface that is part of a control input device such as a knob, button, fader, etc., and that has a capacitance to or close to ground when the control input device is mounted on a capacitive touch sensor. A so-called "virtual ground" can replace the human body ground of a finger touch (but it is of course still valid if a finger touches). BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0054] Figure 1 is a schematic diagram illustrating aspects of controlling an input device according to an embodiment;

[0055] Figure 2 is a perspective view of a button array according to one embodiment in which each button is a control input device;

[0056] Figure 3 is a perspective view of a slider control according to an embodiment;

[0057] Figure 4 is a perspective view of a rotation control according to an embodiment;

[0058] Figures 5 to 7 is based on Figure 2 a diagram of an embodiment of a control input device showing selected features in more detail;

[0059] Figure 8 is a diagram of an embodiment of a button array in which more than one actuation type is accommodated in a control input device.

[0060] Fig. 9 and Fig.10 is based on Figure 3 A diagram of an embodiment of a slider-type control input device showing selected features in greater detail.

[0061] Figures 11a to 11c is based on Figure 4 A diagram of an embodiment of a rotary control input device; and

[0062] Fig.12a and Figure 12b Another embodiment is shown in which multiple electrodes are used to communicate the state of the actuator. DETAILED DESCRIPTION

[0063] Figure 1 is a schematic diagram of a control input device for a capacitive touch screen according to an embodiment.

[0064] The control input device 10 includes a base 20 for mounting the device in a suitable position on a capacitive touch screen 40 .

[0065] The control input device 10 also includes an actuator 30. The actuator 30 is supported by and electrically insulated from the base 20. The actuator 30 includes a conductive surface 35 and also includes an electrode 36 that contacts or is adjacent to the capacitive touch screen 40 when the base 20 is in place.

[0066] Circuit 37 connects electrode 36 and conductive surface 35. Conductive surface 35 has a surface area selected so that conductive surface 35 provides infinite or nearly infinite capacitive coupling. The capacitive coupling between electrode 36 and capacitive touch screen 40 can be detected by controller 41 of the capacitive touch screen. Electrode 36 is configured to undergo a change corresponding to the state of actuator 30. Controller 41 of touch screen 40 can determine the state of actuator 30 based on the change of electrode 36.

[0067] The control input device 10 can be implemented in many forms, examples of which are shown and described in the following embodiments. In addition, not only can the form of the control input device vary (rotary, slider, push button, etc. (or a control input device including a combination of these), the effect of the actuator 30 and the operation of the circuit 37 can also vary between embodiments and / or change the operating mode of the embodiment. Therefore, it will be understood that the following embodiments are merely illustrative and that feature combinations other than those described and shown can also be implemented, depending on the desired application field of the control input device and the number and type of control inputs that the designer wishes to provide.

[0068] Figure 2 2 is a perspective view of a button array housed in a common base 20 in which each button 30 is a control input device according to one embodiment. It will be understood that a single button may be a control input device, but a control input device may also be scaled to include many actuators.

[0069] Figure 3is a perspective view of a slider controller that can be used as, for example, a fader.

[0070] Figure 4 is a perspective view of a rotation control according to another embodiment. In this embodiment, two different control actuators 30a, 30b are combined in the device and their states can be sensed to the touch screen via corresponding tracks on the base 20 marked as 36a and 36b.

[0071] Figures 5 to 7 is based on Figure 2 Figure 2 is a diagram of an embodiment of a control input device showing selected features in more detail.

[0072] In this embodiment, each control input device is a push button 30. In the embodiment shown, the button array is centrally housed in a common chassis (base) 20. However, they may be individually packaged and used individually.

[0073] like Figure 5 As shown, each button has a conductive surface 35 in the form of an actuator frame. The actuator frame 35 is mounted to the chassis 20 and provides infinite or near-infinite capacitive coupling. A circuit (in the form of a switch connection in this embodiment) connects the actuator frame 35 to an electrode 36 via a switch 37. The electrode 36 is adjacent to or in contact with the touch screen and is configured to present a change in capacitive charge to the touch screen when the switch is closed by pressing the button.

[0074] When Figure 6 When the button is pressed, a downward force F1 is applied. In this embodiment, each button floats within the chassis and includes a bearing 60a, 60b connected to a spring post 61a, 61b (preferably, the bearing and spring post are in each corner of the button). The bearings 60a, 60b and corresponding springs 61a, 61b provide reaction forces F2 and F3 and direct the force to the switch 37, which in turn presses the actuator frame to the electrode 36.

[0075] Advantageously, due to the positioning of the bearing and spring post, if the user presses the button off-center, the reaction force is still resolved into a downward force on the switch 37 .

[0076] The depression of button 30 completes the circuit by closing switch 37. This causes a change in capacitance at electrode 36, allowing the controller of the touch screen to determine the state of the button.

[0077] When Figure 7As shown, when multiple buttons are arranged in an array, they can be connected via connection 35a so that they share a common conductive surface 35 (frame). Alternatively, they can have separate conductive surfaces 35. The advantage of the common surface 35 is that the larger body mass presents a capacitive charge. In one embodiment, the common surface 35 can have a reduced width, etc., so as to reduce the area of ​​the touch screen obscured by the frame while maintaining sufficient conductive surface area to provide a virtual ground effect. Figure 7 As shown, each button has a corresponding switch 37a to 37f so that actuation of the buttons can be differentiated.

[0078] like Figure 8 As shown, more than one actuation type can be accommodated in the control input device. In the embodiment shown, the button cap 30 (electrically separated from the frame and the part pressed by the user) can have a conductive coating or be made of a conductive material. In this embodiment, the button cap has a transparent conductive coating and is electrically conductive and connected to a second set of electrodes 71, which can be sensed by the touch screen controller in the same way as other electrodes and provide touch sensing independent of the pressing operation.

[0079] Fig. 9 and Fig.10 yes Figure 3 A diagram of a slider-type control input device showing a selected feature in greater detail.

[0080] In this embodiment, the control input device is a slider-type controller 10 (also known as a fader). The slider 10 comprises an actuator 30 slidably mounted on a chassis (base) 20 (the slider track 21 is part of the chassis 20).

[0081] The actuator 30 includes an electrode 36 that is positioned adjacent to the touch screen and moves relative to the surface of the touch screen as the actuator moves along the track 21 of the chassis 20 .

[0082] As with the push button arrangement described above, the electrode 36 may be positioned adjacent to or in contact with the touch screen 40. In a preferred embodiment, the actuator 30 in one embodiment may have a body 35 formed in whole or in part from aluminum and permanently electrically connected to the electrode 36. Such an arrangement would mean that a touch to the aluminum body 35 could be detected (because the ground signal would increase). Furthermore, due to the position of the electrode 36, the position of the slider could be determined by the touch screen controller. Optionally, the actuator may include a pointer 31 to provide a visual indicator of positioning.

[0083] For ease of understanding, Fig.10A connection 37 between the electrode 36 and the body 35 is shown, but it will be appreciated that this connection is for illustration only and that in reality the connection here is between the body 35 , the spring 38 (also used to hold the actuator on the track 21 ) and the electrode 36 .

[0084] Figures 11a to 11c Shows Figure 4 A diagram of an aspect of a rotational control input device.

[0085] The rotary control input device 10 includes a mounting element (base) 20 for fixing the device in place on the capacitive touch screen and a circuit frame 30 rotatably mounted on the mounting element 20 .

[0086] The circuit frame 30 has a conductor electrically connected to the rotating electrode. In this embodiment, there is an optional component - the circuit frame is divided into two parts (30a and 30b), both of which are connected to their respective (separate) conductive surfaces, each of which has a surface area selected to provide infinite or near-infinite capacitive coupling. In this embodiment, the inner body part 30a is conductive, but is electrically insulated from the outer part 30b by an insulator 31. This enables rotation and push to be sensed by the touch screen separately at their corresponding electrodes 36a, 36b. In this embodiment, the spring 70a connects the inner part 30a to its electrode 36a, and the corresponding spring 70b connects the outer part to its electrode 36b. As with the previous embodiment, providing a virtual grounded conductive surface means that neither rotation nor push actuation requires detection of human body grounding at the corresponding electrodes 36a, 36b.

[0087] In the above embodiments, a single electrode at the capacitive touch screen has been used to signal the state of the actuator. Fig.12a and Figure 12b As shown, more complex arrangements are possible.

[0088] In this embodiment, a first plurality of electrodes (36a ... 36n, although only 36c, 36d and 36e are shown for simplicity of illustration; also for simplicity, only 36c and 36d are shown with wiring connected to the touch screen, but all of the first plurality of electrodes are on the touch screen) are fixed at respective predetermined locations on the capacitive touch screen 40. The control input device 10 has a second plurality of electrodes 37a ... 37h, which are part of the circuit and are positioned in a predetermined pattern so that they are at least partially aligned with the first plurality of electrodes at certain times during rotation, but the alignment of each electrode varies at certain points throughout the rotation. The pattern is selected so that when the control input device is rotated about its fixed rotation axis (here, the control input device is a knob-type control input device), the second plurality of electrodes rotate in a plane substantially parallel to the plane of the touch screen (and therefore the first plurality of electrodes), and as they rotate, they move into and out of alignment with the first plurality of electrodes. The number of first and second electrodes need not be the same.

[0089] In this example, the capacitance presented by controlling the second plurality of electrodes on the input device can be detected by the touch screen controller via the first plurality of electrodes. Figure 12b This is shown only by way of example. Here, it can be seen that electrodes 36a and 36b are positioned above the individual cells of the touch screen. The capacitance value presented at the cell corresponding to the electrode depends on the relative position of the pattern of the second electrode, which changes with the rotation of the controller. A lookup table or the like can be provided, and the capacitance value is mapped to the provided position or the position learned by training and stored in the lookup table. When the touch screen controller 41 needs to determine the position of the control input device, it obtains the capacitance at the first electrode and uses the lookup table to obtain the position of the control input device.

[0090] The arrangement shown enables the use of an 8 bit Gray code, resolving the position into 128 unique codes.Such an arrangement is possible, for example, for the electrode 36, using a 20 mm diameter area.

[0091] In addition to or as an alternative to a lookup table, a learning and / or memory based system can be used to determine position based on the capacitance presented. For example, the controller can be told what the capacitance will be at various increments around the axis of rotation, and the times these capacitances are presented can be tracked, and the position and optionally the degree of capacitance difference compared to the current value can be inferred based on the last known capacitance sensed.

[0092] It will also be appreciated that the pattern of second electrodes connected to the conductive surface may also be modified by methods such as those described above. Thus, different patterns of active second electrodes may be presented depending on the mode of controlling the input device set by the actuator and / or circuitry.

[0093] Alternative embodiments of the present invention may be understood to include the parts, elements and features referenced or indicated herein, individually or collectively, in any or all combinations of two or more parts, elements or features, and where specific integers having known equivalents in the art to which the present invention relates are mentioned herein, such known equivalents are deemed to be incorporated herein as if individually set forth.

[0094] Although the embodiments of the present invention have been described, it should be understood that those skilled in the art may make various changes, substitutions and alterations without departing from the invention as defined by the appended claims and their equivalents.

Claims

1. A control input device for a capacitive touch screen, comprising: A base for mounting the device at a suitable position on the capacitive touch screen; an actuator supported by and electrically insulated from the base, the actuator having a conductive surface and further comprising: an electrode that is in contact with or adjacent to the capacitive touch screen when the base is in place; and an electrical circuit between said electrode and said conductive surface, The conductive surface has a surface area selected so that the conductive surface provides infinite or nearly infinite capacitive coupling so that the capacitive coupling between the electrode and the capacitive touch screen can be detected by a controller of the capacitive touch screen, Wherein, in use, the electrodes are configured to undergo changes corresponding to the state of the actuator, and the controller of the touch screen is capable of determining the state of the actuator based on the changes in the electrodes.

2. The control input device according to claim 1, wherein: The actuator includes a switch connection, wherein a switch is actuated by the actuator.

3. The control input device according to claim 2, wherein: Actuation of the switch is configured to modify the electrical circuit between the electrode and the conductive surface, thereby causing the change.

4. The control input device according to claim 3, wherein: The change includes disconnection of the conductive surface from the electrode.

5. A control input device according to any preceding claim, wherein: The circuit includes a capacitive coupling between the electrode and the conductive surface.

6. A control input device according to any preceding claim, wherein: The circuit includes an optoelectronic component configured to modify the circuit based on a received optical signal.

7. The control input device according to claim 6, wherein: The actuator is configured to control light exposure of the optoelectronic component from the touch screen when the control input device is mounted on the capacitive touch screen.

8. A control input device according to any preceding claim, wherein: During actuation the electrodes change position relative to the touch screen surface, and the change in position of the electrodes can be detected by the touch screen controller.

9. The control input device according to any one of claims 1 to 8, further comprising a first plurality of electrodes at respective predetermined locations on the capacitive touch screen, the control input device having a second plurality of electrodes positioned in a predetermined pattern, wherein Actuation of the control input device causes a change in the relative positioning of the first and second pluralities of electrodes and a corresponding change in capacitance at the first pluralities of electrodes that can be detected by the controller of the touch screen.

10. A control input device system comprising the control input device of claim 9 and further comprising a lookup table mapping capacitance detected at the first plurality of electrodes to a position of the actuator.

11. A capacitive touch screen, comprising: Controller; as well as A control input device according to any preceding claim, wherein the base of the control input device is mounted on the capacitive touch screen, and the electrodes of the control input device are configured to present a capacitance at one or more predetermined locations on the touch screen, Wherein, the controller is configured to scan the one or more predetermined locations to obtain the presented capacitance.

12. The capacitive touch screen according to claim 11, wherein: The controller includes control logic for determining a state of the actuator based on the presented capacitance.

13. The capacitive touch screen according to claim 11, wherein: The controller includes control logic for determining a state of the actuator based on the value of the presented capacitance.

14. The capacitive touch screen according to claim 11, 12 or 13, wherein: The controller includes control logic for determining a state of the actuator based on a location of a presented capacitance on the touch screen.

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