Device and method of a control interface that is sensitive to a movement of a body or object, and a display screen equipped with this device.

Description

technical field

[0001] The present invention relates to a control interface device, particularly a gestural and / or tactile one, possibly combined with voice control, sensitive to the movement of a body or object or to voice. It also relates to a control interface method implemented in this device, as well as control equipment implementing such a device.

[0002] The field of the invention is more particularly, but not limited to, that of human-machine interfaces, gestural and / or tactile, and possibly vocal, allowing in real time to interpret movements of the body, hand, finger or an object, over a great distance up to touch, these movements being combined or not with a voice request in order to execute one or more commands. Prior art

[0003] Virtual human-machine interfaces—that is, gesture-based, touch-based, and / or voice-based interfaces—as opposed to interfaces where the user interacts with mechanical sensors such as keyboard keys or switches, are most often 3D cameras in the case of gesture-based interfaces and active surfaces, often transparent and integrated into display screens, in the case of touch-based interfaces. These touch interfaces are widely used under the name "touchpad" for numerous industrial and consumer applications, such as smartphones, home automation systems, and gaming interfaces.

[0004] The screen can display, for example, a keyboard or a software interface whose image changes in response to user actions. These actions generally consist of moving, tapping, or prolonged contact of a finger or stylus on the screen surface to execute commands. More recently, gesture-based interfaces have been developed to address the increasing complexity of digital products resulting from the convergence of information, communication, and entertainment technologies. These interfaces are most often based on a 3D camera and image processing capable of interpreting body or hand movements from a distance of up to 5 meters to interact with the screen.

[0005] Among the virtual commands, we must also mention the voice command, which allows the execution of a request using voice.

[0006] Among existing touch technologies, capacitive technologies are frequently used because: They do not require exerting mechanical action on the screen surface, unlike resistive techniques for example; they are well suited to meshing the screen surface with a network of sensors directly integrated into the surface of the latter, which allows for a much more compact and robust integration than with optical techniques for example which require a network of transmitters and receivers raised above the detection surface.

[0007] Increasingly, virtual interfaces are being sought to include proximity detection capabilities, enabling the creation of new modes of human-machine interaction without any physical contact. Sensors must therefore be able to detect movements or shapes several centimeters away, with sufficient precision and resolution to translate them into commands.

[0008] While optical technologies are essential when it comes to accurately detecting movements at very long distances (beyond 40 centimeters), capacitive technologies are very well suited for contactless proximity interfaces, particularly because all the sensors can be integrated into a non-planar active surface, for example a screen, without dead zones or without requiring external devices (cameras).

[0009] Among capacitive touch interfaces, the most commonly used techniques are generally based on the principle of charge transfer. These allow for sensitivity on the order of picofarads but are not suitable for creating a gesture interface. Indeed, their sensitivity is insufficient to detect the approach of a finger because the generated capacitance does not exceed a few hundredths of a picofarad. The parasitic capacitances present in this type of sensor and in the electronics prevent any improvement in sensitivity.

[0010] Furthermore, these techniques are highly sensitive to electromagnetic interference, stray electrical charges, and the electrical conductivity of the dielectric coating the electrodes. When the relative humidity of the air exceeds 60%, most dielectrics become slightly conductive, and the charges generated by the electronics are altered, thus disrupting the capacitive measurement.

[0011] Among the technical solutions used to create non-touch capacitive interfaces, some employ a pseudo-guard to significantly reduce parasitic capacitance in the sensor and electronics. However, these techniques only provide a small increase in sensitivity, at best allowing the detection of a finger just a few millimeters from the sensor's sensitive surface.

[0012] Regarding capacitive gesture interfaces, we are familiar with US patent 6,847,354 by Vranish, in which capacitive sensors with active guarding are implemented. This active guarding is created using a unity-gain amplifier that generates a voltage in the guard with an amplitude identical to that of the measuring electrode.

[0013] The drawback of this method is that, by its very nature, the electronics generate parasitic capacitances. These capacitances correspond to the sum of the input capacitances of the amplifier used to generate the active guard (also called pseudo-guard) and of the circuit used to excite the measuring electrode. These parasitic capacitances easily reach picofarads and are added to the capacitance being measured, which may represent only one-hundredth of this total value.

[0014] Furthermore, the capacitance measurement is not direct because Vranish's electronics obtain the image of the capacitance to be measured by measuring its current through a reference resistor. This resistor generates a parasitic phase shift in the electrical current, which significantly degrades the quality of the detection or demodulation of the signal representing the capacitance being measured. Another drawback is the level of crosstalk between the different electrodes. Indeed, each electrode is driven by an operational amplifier with an approximately unity gain. The slightest difference in gain between the different amplifiers causes a significant additional parasitic capacitance.

[0015] These drawbacks make it impossible to detect and locate the position of an object such as a finger or a hand at several centimeters or even tens of centimeters with each sensor.

[0016] Furthermore, the capacitive technologies used for gesture interfaces were most often developed with the aim of being integrated into screens or at least relatively flat surfaces. The sensor structures are matrix-based, as in US 6,847,354, and interfaced by electrode structures arranged in an XY grid. These technologies are not well-suited to the instrumentation of surfaces with more complex shapes.

[0017] In particular, they are difficult to apply to virtual control devices or gesture interfaces based not on an instrumented flat surface but on other types of geometries including cavities, reliefs, undulations simulating for example keys, buttons or enveloping the user in which sensors can be arranged according to various geometries, sometimes under dielectric materials of significant thickness, and must sometimes be able to be arranged and managed independently of each other.

[0018] We are familiar with document FR 2,884,349 by Rozière, which discloses a system based on capacitive sensors with a single measuring electrode. The device can detect objects beyond 10 cm with each electrode, thanks to floating-bridge electronics. The electrode measurements are read sequentially using a scanning system.

[0019] However, this device, intended to equip walls of mobile instruments, is specifically designed to cover anti-collision applications, and does not cover gesture interface applications.

[0020] While gesture-based interfaces are poised to become increasingly important, touch remains crucial, even in virtual interfaces capable of detecting movements remotely, primarily for psychological and safety reasons. Indeed, on the one hand, tactile sensation contributes to user comfort, and on the other hand, touch enables effective validation of commands in safety-critical environments (medical equipment, vehicles).

[0021] The aim of the present invention is to provide a gesture interface and a gesture and touch interface, comprising a device and a method for controlling actions and entering commands, which is compact and integrable into a wide variety of environments, while also allowing: to anticipate actions through precise contactless movement measurements, and to securely validate orders by detecting physical actions on a surface.

[0022] US 2006 / 097991 A1 discloses a multi-touch screen.

[0023] US 2009 / 009485 A1 discloses a court order for capacitive touchpads. Description of the invention

[0024] The aforementioned objective is achieved by the invention defined in the independent claims; modifications of the invention are defined in the dependent claims.

[0025] This objective is achieved with a control interface device sensitive to the movement of a body or object, comprising: a detection surface, at least one capacitive sensor, which sensor(s) each comprise a measuring electrode having an active surface oriented towards the detection surface, or substantially coinciding with said detection surface, electronic excitation and processing means for exciting the measuring electrodes to an alternating electrical potential and processing the signals from said measuring electrodes, so as to measure the capacitance between said measuring electrodes and an object and provide distance information between the active surface of said measuring electrodes and said object, wherein: the measuring electrodes are made of substantially transparent conductive materials, and the control interface device is substantially transparent, and characterized by: a guard made of electrically conductive material disposed near the measuring electrodes at least on their face substantially opposite to the active surface, which guard being excited at an alternating electrical potential substantially identical to that of the measuring electrodes, and in which the guard is made of substantially transparent conductive materials.

[0026] According to the invention, the active surfaces of the measuring electrodes are independent of each other, and the electronic excitation and processing means are further arranged to interrogate said measuring electrodes independently of each other.

[0027] Advantageously, the electronic excitation and processing means can exhibit a measurement range allowing both: to detect and identify a relative movement of the body or object with respect to the active surface of the measuring electrodes, and to detect a contact of said body or object with the detection surface.

[0028] The detection space is defined as the portion of space in which capacitive sensors are able to detect an object and measure its distance.

[0029] Objects detectable with a device according to the invention are capacitively detectable objects, that is, substantially electrically conductive and capable of forming an electrical mass. These objects are not necessarily connected to ground by an electrical connection, but they can be naturally connected by capacitive coupling. Non-limiting examples include a living being, a hand, a finger, or a stylus made of conductive material held in the hand.

[0030] The device according to the invention makes it possible to measure, at every instant, the shape of the surface of the body or object relative to the position of the capacitive sensors. The detection of the movement of an object or body can thus include, but is not limited to, its position in space, its trajectory, and the analysis of its shape for identification purposes, for example.

[0031] Advantageously, the electronic excitation and processing means can at least partly be referenced to the electrical potential of the guard.

[0032] This floating-bridge electronic configuration eliminates parasitic capacitances. Thus, the capacitances measured by each sensor are directly those created between the target object and the electrodes. The device's sensitivity is optimized, enabling highly resolved long-range measurements. Furthermore, the capacitive sensors and their associated electronics can be optimized to achieve a wide measurement range, or dynamic range. Indeed, the range of capacitances measured with each electrode can extend from less than a thousandth of a picofarad to several picofarads, representing a capacitance dynamic range exceeding 1000. This dynamic range allows for the detection, with virtually the same lateral resolution related to the electrode size, of the presence or position of a distant object, such as a finger more than 5 cm away, as well as the contact and pressure of this finger, for example, on a dielectric covering the measuring electrode.In this way, the device according to the invention makes it possible both to anticipate actions by identifying the approaching object or its mode of approach, and to validate commands by detecting contact.

[0033] According to another advantageous aspect of the device according to the invention, each capacitive sensor comprises a single measuring electrode that is independent of the electrodes of the other sensors. This makes it possible to arrange the electrodes in a wide variety of geometries and surface shapes. This electrode independence is a particularly advantageous aspect of the device according to the invention for creating gesture interfaces based on structures of any shape, and in this respect, it differs from gesture interfaces of the prior art based on matrix structures of sensors arranged on flat surfaces or screens.

[0034] In specific embodiments, the electronic excitation and processing means may include scanning means for sequentially reading the measurement signals from the capacitive sensors. Electrodes not being scanned may advantageously be connected to the guard potential.

[0035] In this embodiment, the electrodes are selected sequentially to limit the number of components and energy consumption. Connecting the electrodes not being scanned to the guard potential minimizes the electrostatic edge effects of the measuring electrode.

[0036] In other embodiments requiring more components, each electrode can be connected to an electronic circuit, such as a charge amplifier. These electronic circuits are referenced to the floating electrical potential, i.e., the guard potential, thus preserving the advantageous property that each electrode acts as a guard for its neighbors. This solution increases the measurement speed because capacitances or distances can be measured in parallel across all electrodes.

[0037] It is of course possible to implement other methods of scanning the electrodes, such as, for example, a reading by group.

[0038] In particular embodiments, the electronic excitation and processing means may include means for electrically grouping measuring electrodes, such that said grouped electrodes constitute a single measuring electrode.

[0039] This allows for the creation of larger surface area electrodes, increasing the measurement range to detect objects at greater distances. The electrode grouping configuration can, of course, be performed electronically and controlled by computing resources. For example, the measuring electrodes can be grouped together when the object is far from the panel to maximize the measurement range, and ungrouped when the object is close to the electrodes to improve spatial resolution and the accuracy of the object's three-dimensional position.

[0040] Advantageously, The surface area of ​​the electrodes can be calculated so that each capacitive sensor can measure the distance between the active surface of the electrode and a finger up to a distance of at least 3 cm, or, depending on the application, 5 cm. The measuring electrodes can be made on a flexible printed circuit board substrate. Thus, they can be manufactured using conventional electronic circuit fabrication techniques and arranged on surfaces or sets of surfaces that are not necessarily planar. The measuring electrodes can also be made on a rigid printed circuit board substrate; the electronic excitation and processing means, referenced to the guard potential, can be mounted on the same substrate as the electrodes.

[0041] The fact that part of the electronics is referenced to the guard's potential allows it to be advantageously placed near the electrodes without risking interference, thus improving the device's integration. Indeed, if these electrical circuits were referenced, for example, to an external ground potential (a potential close to that of the object or finger), the electrode field lines would be absorbed very quickly by these circuits, and the device's range would not allow for contactless detection. This is a major problem encountered in many prior art devices.

[0042] Advantageously, the part of the electronics referenced to the guard can communicate with external systems using the reference ground of those external systems. The connection and decoupling between the capacitive electronics and the outside can, for example, be achieved using optocouplers or choke inductors. The floating part referenced to the guard can be powered by a DC-DC converter or choke inductors.

[0043] According to another aspect of the invention, the device may further comprise a dielectric material disposed on the side of the active surface of the measuring electrodes. In this case, the surface of said dielectric material opposite the electrodes constitutes the sensing surface.

[0044] Advantageously, The dielectric material can be arranged so as to be substantially in contact with the active surface of the electrodes; the dielectric material may include a flexible material allowing the sensing surface to deform substantially in the direction of the measuring electrodes by local thinning of the material under the action of a support force.

[0045] Using a flexible material advantageously allows the pressure exerted on the surface to be detected by measuring the displacement of the object below the position of the detection surface at rest.

[0046] According to another embodiment, the dielectric material may comprise a substantially rigid plate, capable of moving towards measuring electrodes under the action of a support force, at an inclination depending on the point of application of said support force.

[0047] The plate can be equipped with capacitively detectable electrodes on at least part of its surface, allowing its displacement or deformation to be measured using strategically placed capacitive electrodes. This plate could be, for example, a keyboard subjected to pressure from an object or a finger. With at least two capacitive electrodes positioned opposite electrodes on the plate and measuring the distance to these electrodes, it is possible to measure the keyboard's tilt and estimate the approximate area where the finger is pressing.

[0048] In another configuration, an assembly, for example a keyboard, comprising a dielectric plate covering first measuring electrodes, may be able to move globally under the effect of pressure towards second measuring electrodes, which measure this pressure.

[0049] Advantageously, these second electrodes can have optimized sensitivity for small displacements.

[0050] Advantageously, The dielectric material can be selected to have a pleasant texture to the touch, and the sensing surface can have embossed shapes representing commands.

[0051] The detection surface can be flat, but also any shape allowing for optimal integration in terms of aesthetics and ergonomics. For example, and without limitation, it can be spherical or hemispherical to mimic a computer mouse or part of a control panel on a medical device.

[0052] A device according to the invention can be integrated in a wide variety of configurations, for example into an armrest of a wheelchair for disabled people, or into the dashboard of a vehicle. In particular, it allows for the replacement of electromechanical control buttons, for reasons of reliability, for example.

[0053] Without loss of generality, the detection surface can be likened to a control panel. Preferably, the measuring electrodes are placed side-by-side to avoid dead zones on the panel, where objects are not detected. Alternatively, dead zones can be intentionally created by replacing the electrode with a guard or a ground, thus deflecting the field lines of neighboring electrodes to reduce or modify their range.

[0054] To achieve a good compromise between lateral resolution and object detection range, it is advantageous to choose an electrode size roughly of the same order of magnitude as the object. For example, to optimize the detection of a finger, it is advantageous to choose an electrode surface area on the order of 1 cm² to 2 cm².

[0055] The shape of the electrodes can be adapted according to the desired detection characteristics, and several electrode shapes can exist within the same device. For example, electrodes of a particular shape, such as rectangular, can be placed on the edges of a control panel to detect which side a finger or hand is approaching from. This can allow the device, for instance, to select the actions authorized for a person, depending on the side from which they approach the panel.

[0056] A device according to the invention can provide as output data, in a non-limiting manner, either analog measurement signals, or signals in digital form, or directly the distances separating the electrodes from the object, or directly, for example, the three-dimensional position, the analysis of the object's movements, the identification of the object, or control commands.

[0057] For three-dimensional detection, each electrode of the device can be considered a pixel, and the physical spatial resolution is limited by the surface area of ​​the electrodes. This spatial resolution can be significantly improved using numerical interpolation methods. One method, for example, involves calculating the center of gravity of the object "seen" by all the electrodes. This theoretical center becomes a virtual point that can be visualized on a screen. This allows, for example, writing, drawing, or precise manipulation of a small area displayed on a screen using an object such as a finger or hand.

[0058] Three-dimensional detection also allows the device to be used as a capacitive camera. Indeed, the system can measure in real time the absolute distance separating each electrode from the target object, and with a sufficient number of electrodes, it is possible to image or recognize that object.

[0059] The device according to the invention also aims to detect contact between the object (or finger) and the detection surface (or control panel) with sufficient certainty to guarantee the desired operational reliability. To this end, knowing the position of the detection surface, for example through calibration, it is possible to determine contact directly from measuring the object's distance when the object is detected to be at a distance corresponding to that of the surface.

[0060] In an advantageous embodiment where the detection surface is a dielectric material in contact with the electrode surface, contact can be detected more reliably by analyzing the capacitance between the object and the electrode. When a finger, for example, comes into contact with the dielectric surface, there is practically no air along the path of the electric field lines between the finger and the electrode. The dielectric material has a dielectric permittivity higher than that of air, on the order of, for example, εr = 3. Consequently, the capacitance between the finger and the electrode is significantly higher when the finger is in contact with the surface, compared to the case where a thin layer of air remains, thus enabling more reliable contact detection.

[0061] It is also possible, in a device according to the invention, for the electrodes not to be coated with dielectric material. In this case, contact between the object and an electrode can be detected because the electrode is brought to the object's ground potential upon contact.

[0062] Pressure can advantageously be measured by measuring the penetration of an object such as a finger into a substantially flexible or soft dielectric material covering the electrodes. The measured distance is substantially proportional to the penetration of the finger into the dielectric material. Furthermore, the change in the measured distance, which is also substantially proportional to the inverse of the capacitance, is multiplied by the relative permittivity εr of the dielectric covering the electrode, resulting in an increase in the sensitivity of the distance measurement whenever there is contact between the finger or object and the dielectric.

[0063] Another solution for measuring pressure may be to measure the increase in capacitance due to the increase in the bearing surface of an object such as a finger in contact with the surface of a relatively rigid dielectric material, when the pressure exerted increases.

[0064] The present invention thus makes it possible to detect, without contact and at distances of several centimeters or even decimeters, the position of a finger or object in space, to detect contact of the finger or object with a detection surface such as a control panel or keyboard, and also to detect the pressure exerted by the finger or object on this surface. The measurement can be performed through any dielectric material. These characteristics allow for the creation of highly sophisticated, aesthetically pleasing, and ergonomic control interfaces with possibilities for combining original commands.

[0065] For example, it is possible, in a non-exhaustive way, to recognize signs by the movement of the fingers, to determine the side of the active surface by which a hand arrived in order to control actions authorized or not by the different people in front of the interface and to validate a major command by a touch or a press of the finger on the keyboard.

[0066] The use of a device according to the invention is of course not limited to the detection of a single finger, and commands resulting from the simultaneous or non-simultaneous movements of several fingers can be envisaged.

[0067] A device according to the invention can detect the position of a finger through any type of dielectric, even one several millimeters or centimeters thick. This advantage allows for the design of control devices with an infinite variety of shapes, textures, colors, and tactile sensations, making them more user-friendly. For example, high-quality materials such as wood, leather, ceramic, or any type of rigid or flexible polymer, such as silicone, can be used. In particular, a soft material like silicone can provide a more pleasant tactile experience.

[0068] Advantageously, the dielectric can be easily replaced, particularly for reasons of hygiene or aesthetics. This dielectric can be a material suitable for washing or sterilization, making the device according to the invention particularly well-suited for creating interfaces in environments where hygiene is important.

[0069] The invention may also relate, but is not limited to: a control equipment providing a human-machine interface function integrating a capacitive motion detection device according to the invention, a control equipment intended to be integrated into a vehicle, comprising a capacitive motion detection device according to the invention, a sensitive wall structure integrating a control device according to the invention.

[0070] In another respect, a method for a control interface sensitive to the movement of a body or object is proposed, implementing a device according to the invention, comprising: an excitation of one or more measuring electrodes within at least one capacitive sensor, said measuring electrodes having an active surface oriented towards a detection surface, or substantially coinciding with said detection surface; processing of signals from said capacitive sensors so as to provide distance information between the active surface of the electrodes and said object, characterized in that: said measuring electrodes being provided with a guard made of electrically conductive material disposed near the measuring electrodes at least along their face substantially opposite to the active surface, an excitation of said guard being at an alternating electrical potential substantially identical to that of the measuring electrodes, the measuring electrodes have independent active surfaces and are interrogated independently of each other.

[0071] In a particular embodiment, the method according to the invention, which comprises measuring at least one distance between the object and the detection surface, and processing said distance measurements to provide approach information, is characterized in that it further comprises: A measurement of the contact between the object and the sensing surface, and processing of said contact measurements to provide touch information. The contact can, of course, be a light touch on the surface. According to advantageous aspects, the detection of the contact between the object and the sensing surface may include a comparison of measured capacitances with at least one threshold value; the processing of distance measurements may include detection of the object's position in space obtained at least from the distance measurements and knowledge of the arrangement of the capacitive sensors; and the processing of contact measurements may include identification of the capacitive sensors that detected contact between the object and the sensing surface.

[0072] The method according to the invention may further include: a measurement of the displacement of the detection surface under the action of the object, a processing of said displacement measurements to provide supporting information.

[0073] Advantageously, The method according to the invention may further include a step of determining commands, which commands being conditioned at least by at least one of the approach, touch and support information, at least one command determined by any one of the touch and support information may be conditioned by the approach information, at least one command may be conditioned by the temporal evolution of at least one of the approach, touch and support information.

[0074] Thus, the process according to the invention makes it possible to generate commands by taking into account up to three levels of information: approach information, touch information, support information.

[0075] Of course, the three levels of information can appear and be processed simultaneously, and this information can include the temporal evolution of the measurements or their history.

[0076] By way of example, Approach information can include, for example, distance, trajectory, and the identification of one or more objects based on their shape. This information can be used, for instance, to adapt the interface to the current action mode: activation, selective lighting, adapting the interface for use by a left-handed or right-handed user, by a hand or a stylus, etc. Touch information can include, for example, the point of contact, single or simultaneous trajectories on the surface, and single or repeated taps. This information can be used, for example, to validate commands (buttons), enter data (writing), scroll or zoom a display, etc. Pressing information can include, for example, pressure at a specific point, along one or more trajectories, single or repeated firm taps, and the duration of the press.For example, they can be used to perform proportional commands (adjusting speed, intensity), lock commands, ... .

[0077] The ability to reliably distinguish between approach and touch (or swipe) is fundamental for interfaces intended for applications requiring a certain level of security. This addresses a basic security requirement that an order must be selected and then validated to prevent unintended actions.

[0078] Advantageously, with the method and device according to the invention, selection can be made without contact, which allows for considerable increased flexibility. Approach detection and analysis can also be used to give the device an anticipatory or order-preparing capability, which can also be a safety feature.

[0079] These safety requirements are found particularly for interfaces intended for medical equipment or vehicles, especially automobiles, for which the device and method according to the invention are particularly well suited.

[0080] Of course, the device and method according to the invention are not limited to security-related applications. Generally speaking, the following non-limiting examples of possible applications can be cited: The wide range of applications for three-dimensional control in general, including gesture control, known for example by names such as "3D touch panel", "3D gesture controllers", "3D floating vision"; Home automation, with, for example, controls for lighting, air conditioning, shutters, door opening... Household appliances, for all kinds of control and programming of devices such as washing machines,... User interfaces for portable devices, phones, GPS,... User interfaces for office and IT equipment, computers,... Interfaces for gesture-controlled electronic games; Interfaces for piloting and controlling vehicle functions in general, including in the military and aviation sectors;

[0081] In yet another respect, a device according to the invention can be combined with other contactless detection and / or identification means to create comprehensive gesture interfaces comprising multiple levels of user detection. For example: to locate a user, for example in a vehicle, using capacitive sensors with a longer measurement range, or optical or ultrasonic sensors, so as to preconfigure a gesture interface according to the invention. For example, certain functions can be configured differently depending on the position and number of occupants; to identify, for example with a camera and image recognition means, the movements and / or characteristics of a user (gender, clothing, identity, morphology or any other characteristics...) so as to adapt the gesture interface to their needs or, for access control applications, to their authorization level.

[0082] Thus, a multi-scale gestural interface is proposed, integrating a control device according to the invention, characterized in that it further includes optical imaging means such as a 3D camera.

[0083] Advantageously, these optical imaging methods may include an optical camera.

[0084] A method according to the invention is also proposed, implementing a multi-scale gestural interface, characterized in that it further comprises: an object detection step by optical imaging, providing image information, and a processing step of this image information to determine one or more commands.

[0085] In another respect, a device according to the invention can advantageously be combined with a voice interface. Thus, a gesture and voice interface is proposed, incorporating a control device according to the invention, characterized in that it includes means for recognizing voice commands.

[0086] A method according to the invention implementing a voice interface is also proposed, characterized in that it further comprises: A speech recognition step, and a step of processing this speech information to determine one or more commands.

[0087] In yet another respect, a device according to the invention can advantageously be combined with a multi-scale gesture interface including optical imaging and speech recognition means to create a comprehensive virtual interface thus encompassing several technologies. It is then possible, for example, to execute commands using multi-scale gestures and voice commands.

[0088] Thus, a multi-scale capacitive, optical and vocal gesture interface is proposed, integrating a control device according to the invention, characterized in that it includes optical gesture recognition means and voice control means.

[0089] A method according to the invention implementing a voice interface is also proposed, characterized in that it further comprises: an object detection step by optical imaging, providing image information, and a step of processing this image information to determine one or more commands, a speech recognition step, and a step of processing this speech information to determine one or more commands. Description of the figures and methods of implementation

[0090] Other advantages and features of the invention will become apparent upon reading the detailed description of implementations and embodiments, which are by no means limiting, and the following attached drawings: there figure 1 illustrates a general diagram of the device according to the invention, the figure 2 illustrates modes of interaction with the device according to the invention, the figure 3a method for detecting contact between an object and the device according to the invention, the figure 4 illustrates an example of grouping measurement electrodes to increase the device's range, the figure 5 illustrates an example of an embodiment of a device according to the invention, the figure 6 illustrates another example of an embodiment of a device according to the invention, as well as examples of interaction modes, the figure 7 illustrates a first embodiment of the electronic excitation and processing means, the figure 8 illustrates a second embodiment of the electronic excitation and processing means.

[0091] With reference to the figure 1 The device according to the invention comprises a set of capacitive sensors made on a double-sided flexible printed circuit 1. The measuring electrodes 2 are etched on one side of the printed circuit 1, while the second side of the circuit supports the guard 3.

[0092] Each electrode 2 is connected by a connecting track 6 to the excitation and measurement electronics 7. The connecting tracks 6 are etched on the same side of the printed circuit board 1 as the electrodes. The guard 3 is also connected to the electronics 7, which is floating and referenced to the potential of this guard, by an electrical connection 5. Depending on the device configuration, the electrical connections 5 and 6 may include coaxial cables.

[0093] A plate of dielectric material 14, for example silicone, is placed in front of the electrodes 2, so as to be in contact with their active surface.

[0094] With reference to the figure 2, when an object 11 such as a hand or a finger approaches the device, an electrical coupling is created with the capacitive electrodes 2. The electrodes 2 and their associated electronics 7, 9 measure the capacitance C that is established between them and this object 11, so as to deduce the distance 13 by the relation: C = ε 0 ⋅ εr ⋅ S / D , where ε 0 is the permittivity of free space, ε r is the relative permittivity of the dielectric material 14 or of air, which are to be taken into account over the distance where they are present, S is the surface area of ​​the electrode, on the order of for example 1 to 2 cm 2< to detect a finger under good conditions, and D is the distance to be measured.

[0095] Measuring the distance D or the capacity C allows us to determine: the distance of object 11 as it approaches ( figure 2a), the physical contact between object 11 and the detection surface 4, which corresponds to the case where the distance D is substantially equal to the thickness Dc of the dielectric material, with known characteristics ( figure 2b ), and, where applicable, the penetration of the object 11 into the dielectric material 14, which corresponds to the case where the distance D is substantially less than the thickness Dc, ( figure 2c ), and which can be translated in terms of pressure or force.

[0096] Physical contact detection is of particular interest for the actuation reliability of a control system, for example. This detection is significantly improved by the presence of the dielectric material. figure 3This graph compares the evolution of the capacitance measured by an electrode 2 with a surface area of ​​2 cm², as a function of the distance D to an object 11, in the presence of a dielectric material 14 with relative permittivity εr = 3 and thickness Dc = 5 mm (curve C) and in the absence of this material (curve Ca). It can be seen that in the presence of material 14 (curve C), the measured capacitance increases sharply when object 11 is in the immediate vicinity of the material's surface.

[0097] Contact can thus be detected with greater sensitivity the higher the relative permittivity of material 14. This detection can advantageously be carried out by comparing the measured capacitance with one or more threshold values.

[0098] Similarly, when the object sinks into a flexible dielectric material 14 ( figure 2cIts position can be measured with greater sensitivity as the relative permittivity of the material increases. This advantageously allows for precise pressure measurements by measuring relatively small displacements.

[0099] A key feature of the device according to the invention is its ability to perform highly accurate measurements, both at distances of several centimeters or even decimeters, and in the immediate vicinity of the electrodes. This is achieved through the implementation of an electronic process that provides both high sensitivity and excellent immunity to electromagnetic interference in the environment. Immunity to interference is, in fact, extremely important in the context of digital control devices.

[0100] The electronics implemented in the present invention is based on the floating bridge measurement method described in document FR 2,756,048.

[0101] There figure 7This presents a first example of an electronic embodiment. The capacitance of electrode 2 is measured by a capacitance meter 7 referenced to the guard potential 34, which is completely floating relative to the general ground 10. The guard 3 and electrodes 2 are excited at a fixed-frequency alternating voltage by means of circuit 7, so as to allow synchronous demodulation of the measurements. The floating electronics 7 are powered, for example, by a DC / DC converter 30. The measurement signal after demodulation is transferred to circuit 9, which is referenced to the general ground, by a differential amplifier 33 so that it can be transmitted to the computing means. A multiplexer 31 allows the electrodes 2 to be interrogated sequentially, while the inactive electrodes are maintained at the guard potential 34.

[0102] There figure 8 presents a second example of how electronics can be implemented. It differs from that of the figure 7 in that all 2 electrodes have their own 35 sensing electronics and can be read simultaneously.

[0103] Specific implementation methods follow, the DC / DC converter 30 can be replaced by a less expensive power supply referenced to the general ground 10, and coupled to the floating circuit 7 by "chop inductors" or stop coils, the differential output amplifier 33 can be replaced by optocouplers or choke inductors.

[0104] The electronics used allows the measurement of capacitances from the order of 0.001 pF (picofarads) up to a few picofarads, with an accuracy of the order of 0.001 pF.

[0105] Taking the example of measuring the position of a finger placed 50 mm from an electrode with a surface area of ​​approximately 2 cm², we can estimate that the measured capacitance is approximately 0.035 pF. Under these conditions and at this distance, the sensitivity of the electronics is 0.7 pF / m and the accuracy of the position measurement is less than 10⁻³ / 0.7 = 1.4 mm.

[0106] As the finger moves further away, sensitivity decreases rapidly because the field lines begin to spread out at the edges. This is because the guard surrounding the selected electrode represents, at most, the entire detection area. For a panel of typical size (100 to 200 mm per side), the field lines of a 2 cm² electrode spread out beyond a distance of approximately 50 mm. With a larger panel, it is theoretically possible to detect a finger at a distance greater than 100 mm, but the lateral resolution will be significantly degraded.

[0107] A hand can be very easily detected at a distance of over 300 mm if the electrodes are grouped together to obtain, for example, an electrode surface area of ​​2500 mm². At this distance, the measured capacitance is approximately 0.073 pF.

[0108] These performances can be achieved using the floating bridge technique because the electronics only measure the capacitance between electrode 2 and object 11. In prior art devices such as in US 6,847,354, the parasitic capacitances generated by the measurement and guard creation circuit remain greater than 1 pF and the stability of this parasitic offset, source of noise, is on the order of a few tens to a few hundred femtofarads.

[0109] The floating bridge technique implemented using an alternating signal excitation with amplitude modulation and demodulation also guarantees very good rejection of the variation of the impedances of the dielectric materials 14 surrounding and covering the electrodes 2.

[0110] Furthermore, the floating bridge has the particularity of directly measuring the inverse of the capacitance between electrode 2 and object 11, which makes it possible to obtain a signal linearly proportional with the distance to be measured 13. This advantage is fundamental because, at large distances, the capacitance varies very little with distance (according to a hyperbolic law), and the natural offsets of the electronics and the means of digitizing the signal drift more than the capacitance to be measured.

[0111] With reference to the figure 4The capacitive electrodes can be electronically grouped, for example by means of the multiplexer 31, to form larger surface electrodes capable of detecting objects at greater distances. In the example of the figure 4 Electrode 44 is formed by combining electrodes 40, 41, 42, and 43. For example, when the device does not detect any nearby objects, it enters a long-range detection mode (Figure 4a). When an object approaches the measurement range of the individual electrodes, the device switches to the laterally resolved mode (Figure 4b) to detect object details. Of course, the reconfiguration can be more complex and depend locally on what is detected by the different zones.

[0112] According to particular embodiments, a device according to the invention may include electrode arrangements very different from a square matrix placed on a uniform surface.

[0113] For example, at the figure 5 , the electrodes are placed under a dielectric material 14 whose detection surface 4 mimics the shape of electromechanical switches such as rotary knobs 20 and push buttons 21. The "pseudo buttons" are provided with electrodes 2 enabling the detection of the approach and then the action of a user.

[0114] There figure 6 illustrates an interface consisting of capacitive electrodes arranged under a hemispherical, flexible dielectric material sensing surface. Such an interface can, for example, easily detect which side a hand is approaching from, whether it is a right or left hand, or multiple hands ( figure 6a ), to interpret a command made with a finger ( figure 6b ) or several fingers ( figure 6c ).

[0115] According to the invention, the capacitive electrodes and the guard can be made using transparent conductive materials such as ITO (tin-doped indium oxide), so that the device is substantially transparent and can be placed on a viewing screen for example.

[0116] Of course, the invention is not limited to the examples just described and many modifications can be made to these examples without departing from the scope of the invention.

Claims

1. A control interface device sensitive to a motion of a body or an object, comprising: - a detection surface (4), - at least one capacitive sensor, each of said sensor(s) comprises a measuring electrode (2) having an active surface oriented towards the detection surface (4), or substantially coincident with said detection surface, - electronic means of excitation and processing (7, 9, 12) for exciting the measuring electrodes (2) to an alternating electric potential and processing signals from said measuring electrodes (2), so as to measure the capacity between the measuring electrodes (2) and object (11) and to provide a distance information (13) between the active surface of the measuring electrodes (2) and the object (11), in which: - the measuring electrodes (2) are realized by means of substantially transparent conductive material, and - the control interface device is substantially transparent, and characterized by: - a guard of electrically conductive material (3) arranged near the measuring electrodes (2) at least according to their side substantially opposite to the active surface, said guard (3) is excited at an alternating electrical potential referenced to that of the measuring electrodes (2) and different from a ground potential, and - in which the guard (3) is realized by means of substantially transparent conductive material.

2. The device according to claim 1, in which it is configured to be placed on a display screen.

3. The device according to one of claims 1 or 2, in which the measuring electrodes (2) and the guard (3) are made by means of ITO (indium tin oxide).

4. The device according to one of the preceding claims, in which: - the active surfaces of the measuring electrodes (2) are independent of each other, and - the electronic excitation and processing means (7, 9, 12) are further arranged to interrogate said measuring electrodes independently of each other.

5. The device according to any of the preceding claims, in which the electronic excitation and processing means (7, 9, 12) have a measuring range allowing both: - detecting and identifying relative movement of the body or object (11) with respect to the active surface of the measuring electrodes (2), and - detecting with certainty a contact of the body or object with the detection surface (4).

6. The device according to any of the preceding claims, in which the electronic excitation and processing means are at least partly (7) referenced to the electrical potential of the guard.

7. The device according to any of the preceding claims, in which the electronic excitation and processing means (7, 9) comprise scanning means (31) for sequentially reading the measurement signals from the capacitive sensors, the electrodes which are not being scanned being connected to the potential of the guard (3).

8. The device according to any of the preceding claims, in which the electronic excitation and processing means comprise means for electrically grouping measuring electrodes (40, 41, 42, 43), such that said grouped electrodes constitute a single measuring electrode (44).

9. A control equipment providing a man-machine interface function including a control interface device according to one of the preceding claims and a display screen.

10. A multiscale gestural interface including a control interface device according to any of claims 1 to 8, in which it further comprises at least one of the following means: - optical imaging means, - means of voice recognition.

11. A control interface method sensitive to a motion of a body or an object, comprising: - an excitation of one or more measuring electrodes (2) within at least one capacitive sensor at an alternating electrical potential, said measuring electrodes comprising an active surface oriented towards a detection surface (4), or substantially coincident with said detection surface, - processing signals from said measuring electrodes (2) so as to measure the capacity between the measuring electrodes (2) and object (11) and to provide distance information (13) between the active surface of the measuring electrodes (2) and the object (11), characterized by: - said measuring electrodes being provided with a guard of electrically conductive material (3) disposed close to the measuring electrodes (2) at least according to their face substantially opposite the active surface, - an excitation of said guard (3) at an alternating electrical potential substantially identical to that of the measuring electrodes (2), - said method being carried out in a substantially transparent control interface device placed on a display screen and provided with measuring electrodes (2) and the guard (3) made of substantially transparent conductive materials.

12. The method according to claim 11, in which it comprises a displaying step on the interface display screen of a software, the image of which evolves in response to the actions of the object (11).

13. The method according to any of claims 11 or 12, comprising measuring at least one distance (13) between an object (11) and a detection surface (4), - processing said distance measurements to provide approach information, wherein it further comprises: - measuring the contact between the object (11) and the detection surface (4), and - processing said contact measuring to provide touch information.

14. The method according to claim 13, in which: - the distance measurement processing comprises a detection of the object position (11) in space obtained at least from distance measurements and knowledge of the arrangement of the capacitive sensors (2), and that - the contact measurement processing comprises an identification of the capacitive sensors (2) having detected a contact between the object (11) and the detection surface (4).

15. The method according to any of claims 13 or 14, in which it further comprises a step of determining commands, which commands are conditioned by at least any of the approach and touch information.

16. The method according to claim 15, in which at least one control determined by a touch information is conditioned by an approach information.

17. The method according to any one of claims 15 or 16, in which at least one control is conditioned by the temporal evolution of at least one of the approach or touch information.

18. The method according to any of claims 11 to 17, implementing a gestural interface according to claim 10, in which it further comprises at least one of the following steps: - a step of detecting the object by optical imaging, providing image information, and processing this image information to determine one or more commands, - a speech recognition step, and processing this speech information to determine one or more commands.