THREE-DIMENSIONAL TOUCH INTERFACE WITH HAPTIC FEEDBACK

Description

DOMAINE TECHNIQUE

[0001] The invention is a tactile interface, with haptic feedback, comprising a three-dimensional control member, the control member being capable of being touched by an external body, for example a user's finger or a stylus manipulated by a user. ART ANTERIEUR

[0002] Conventional interfaces for devices, whether industrial or consumer, frequently use button-type control elements, such as pushbuttons, adjustment knobs, or sliders. This type of element allows the selection and / or adjustment of operating parameters of the device controlled by the interface. Control elements are generally three-dimensional and extend from a surface. The assembly forms a control bay. Control elements can take various forms. They generally include moving parts and electrical interconnections. This results in high manufacturing costs and wear after a certain period of use.

[0003] An alternative to this type of interface has emerged with the development of touchscreens, particularly capacitive touchscreens. These can operate interactively and very intuitively. They are now used both for everyday devices, such as mobile phones and car dashboards, but also in more specialized industrial applications. However, a touchscreen is a surface, usually flat, without texture.

[0004] Devices have been developed that allow a texture sensation to be felt when a user's finger is applied to a flat screen. The principles of such texturing are described, for example, in the publication Biet M. et al., "Squeeze film effect for the design of an ultrasonic tactile plate", IEEE Transactions on Ultrasonic, Ferroelectrics and Frequency Control, IEEE, 2007, 54 (12), pp.2678 - 2688, or in the patent application EP1956466, as well as in the publication Vezzoli et al. "Coupling ultrasonic vibration and electro-vibration for tactile stimulation", Symposium on Electrical Engineering SGE 2014. In the latter, two tactile stimulation techniques are compared, including the so-called ultrasonic vibration effect. In these documents, a tactile interface is described comprising a smooth plate, forming a contact surface intended to be touched by a finger.This plate is vibrated by several piezoelectric transducers, arranged in contact with the plate, below the latter. The transducers and the plate form a resonator conducive to the formation of a stationary flexural wave, of the Lamb wave type. When the vibration resonance frequency of the contact surface is in the ultrasonic domain, for example between 10 kHz and 200 kHz, and the amplitude of the vibration is low, typically a few microns, the user can feel a texturing effect of the contact surface, when the finger slides along said surface. This effect is known and is usually referred to as "squeeze film". The vibration of the plate generates an air cushion between the finger and the plate, reducing the friction of the finger on the plate. This is also called ultrasonic lubrication. By modulating the vibration, the friction of the finger on the plate is modified.The user can thus perceive an impression of texturing, taking the form of a sensation of roughness, or a certain resistance to sliding, while the contact surface remains smooth. This effect has been applied to transparent or non-transparent contact surfaces, forming a haptic interface. This type of interface can be combined with a touch screen.

[0005] However, the presence of three-dimensional control elements in an interface has certain advantages: better handling, operation sometimes considered more intuitive. Three-dimensional elements are also suitable for uses in which the user's visibility is reduced, or when the user cannot devote all of his attention to the interface. For example, when the user is a driver of a car, the control interface for the car's equipment must be as intuitive as possible, requiring the least attention from the driver so that the latter can concentrate on driving.

[0006] Document JP6739692 describes a haptic interface with a three-dimensional control button. The three-dimensional control button is rotatable on a plate. When the control button is rotated, the haptic interface provides haptic feedback by modulating friction between the control button and the plate. This allows a user to perceive modulation of the sliding of the control button on the plate.

[0007] The inventors have designed a device interface that combines the advantages of touch screens and conventional three-dimensional organs. EXPOSE DE L'INVENTION

[0008] A first object of the invention is a touch interface, intended to control a device, the interface being intended to be touched by an external body, and comprising: a plate; at least one transducer, configured to vibrate the plate, preferably at an ultrasonic vibration frequency; the interface being characterized in that it comprises: a control member, extending from the plate, between a proximal end, applied against the plate, and a distal end, located at a distance from the plate, the control member being intended to be in contact with the external body; a sensor, configured to emit a status signal, the status signal being representative of contact of the external body on the control member; a control unit, connected to the sensor, and configured to address, as a function of the status signal, an activation signal to at least one transducer, so as to set the plate and the control member into vibration.

[0009] Thus, the vibration induces an impression of texturing, felt by the external body touching either the plate or the control member. The vibration then constitutes a haptic feedback from the interface, resulting in a modification of a tactile sensation. Preferably, the vibration is an ultrasonic vibration. By ultrasonic vibration, we mean a vibration whose frequency is greater than or equal to 20 kHz. The vibration frequency is preferably less than 200 kHz.

[0010] The status signal may be representative of a pressure exerted by the external body on the control member and / or of a position of the external body on the control member.

[0011] The control unit may be configured to address a control signal to the device based on the status signal.

[0012] The control unit can be fixed against the plate. It can also be removable.

[0013] According to a first embodiment, the sensor comprises a pressure sensor, configured to measure a pressure exerted, in particular under the effect of the external body, by the control member, on the plate, the status signal comprising a pressure component, dependent on the pressure exerted; the control unit is configured to address an activation signal to the transducer as a function of the pressure exerted, in particular when the pressure crosses a predetermined threshold or as a function of a pressure variation.

[0014] The pressure sensor may include: a rangefinder, arranged facing the plate, and configured to measure a distance separating it from the plate, the rangefinder being configured to determine a deformation of the plate under the effect of pressure exerted on the plate; or a strain gauge, arranged to deform under the effect of a deformation of the plate under the effect of pressure exerted on the plate; or a dynamometer, arranged in contact with the plate, and configured to detect a displacement of the plate under the effect of pressure exerted on the plate; or a transducer, configured to measure a variation in a vibration of the plate, the variation resulting from pressure exerted on the plate.

[0015] Depending on the pressure component measured by the pressure sensor, the control unit can be configured to address an activation signal in the form of an activation sequence. The activation sequence is configured such that a click effect is felt by the external body, the click forming a haptic feedback of the interface.

[0016] The activation signal can be established from: of a periodic carrier, the carrier extending, at each period, according to an amplitude; of a modulation function, varying according to the pressure component measured by the position sensor; so that the amplitude of the activation signal results from a modulation of the carrier by the modulation function.

[0017] According to a second embodiment: the sensor comprises a capacitive position sensor, connected to a network of conductive tracks preferably extending parallel to the plate; the control member is formed from an electrically insulating material, and comprises conductive elements, electrically insulated from each other, extending between the proximal end and the distal end; at least one conductive track is arranged in capacitive contact with at least one conductive element of the control member, so as to allow a transfer of charges, by capacitive effect, between the external body, and the conductive track, via the conductive element; so that the status signal includes a position component, dependent on a position of the contact between the external body and the control member.

[0018] The control unit may be configured to address the activation signal to the transducer when the position component undergoes a variation representative of a variation in the position of the contact between the external body and the control member.

[0019] Depending on the position component measured by the position sensor, the activation signal can be configured so that a notch effect is felt by the external body, the notch effect forming a haptic feedback of the interface. The notch effect corresponds to a feeling, by the external body, of at least one virtual notch on the control member. The virtual notch is a felt notch, resulting from the vibration of the plate by the activation signal.

[0020] The activation signal can be established from: of a periodic carrier, the carrier extending, at each period, according to an amplitude; of a modulation function, varying according to the position component; so that the amplitude of the activation signal results from a modulation of the carrier by the modulation function.

[0021] The modulation function can successively include: an anterior phase, when the external body approaches a notch; a notch phase, when the external body crosses the notch; a posterior phase, when the external body moves away from the notch; so that the user's feeling of the virtual notch depends on the modulation function during the anterior, notch and posterior phases.

[0022] The modulation function may be such that during the notch phase, the modulation function varies over a wider range of variation than during the anterior phase and during the posterior phase.

[0023] The anterior, notch, and posterior phases form an activation sequence associated with the virtual notch. The activation signal may comprise several successive activation sequences, each activation sequence corresponding to a virtual notch.

[0024] During the notch phase, the modulation function may be such that an absolute value of its time derivative reaches a higher maximum value than during the earlier phase and during the later phase.

[0025] The haptic feedback of the interface can be likened to a virtual texture, insofar as it is a felt texture, independently of the actual surface condition of the control organ.

[0026] The first embodiment and the second embodiment may be considered independently of each other or in combination.

[0027] According to one possibility, the control organ does not have a moving component relative to the plate.

[0028] The control member preferably has a geometric shape of a button or adjustment wheel or slider.

[0029] The plate is preferably connected to a plurality of transducers. The plate may be rigid, transparent, or opaque. Alternatively, the interface includes a screen. The plate may then be transparent and positioned against or parallel to the screen.

[0030] A second object of the invention is a device, capable of being controlled by a parameter, and comprising an interface configured to select the parameter or adjust a value of the parameter, the device being characterized in that the interface is an interface according to the first object of the invention, the interface being configured to determine the value of the parameter or select the parameter as a function of the status signal.

[0031] A third object of the invention is a method of controlling an interface according to the first object of the invention, comprising: a) application of an external body to the control member; b) formation, by the sensor, of a status signal, representative of a position of the external body on the control member and / or of a pressure exerted by the control member on the plate, under the effect of the external body; c) depending on the status signal, emission, by the control unit, of an activation signal of the transducer or of each transducer; d) under the effect of the activation signal, vibration of the plate, so that a vibration, preferably ultrasonic, propagates through the plate, so as to induce a haptic effect on the external body.

[0032] Thus, the effect of the ultrasonic vibration on the external body constitutes haptic feedback from the interface.

[0033] The interface may be as described in connection with the first embodiment of the first subject of the invention. The method may then be such that: during step a), the external body applies pressure to the control member, in the direction of the plate; during step b), the status signal formed by the sensor is representative of the pressure exerted by the external body on the control member; during step c), the control unit emits an activation signal as a function of the pressure and / or a variation in the pressure.

[0034] The activation signal may be as described in connection with the first embodiment of the first subject of the invention.

[0035] The interface may be as described in connection with the second embodiment of the first subject of the invention.

[0036] The process can then be as follows: during step a), the external body is electrically conductive and moves on the control member, facing different conductive elements; during step b), the state signal formed by the sensor is representative of a variation in the position of the external body on the control member; during step c), the control unit emits an activation signal as a function of the variation in the position of the external body.

[0037] The activation signal may be as described in connection with the second embodiment of the first subject of the invention. The activation signal may take the form of an activation sequence, or of several successive activation sequences. The activation sequence, or each activation sequence, may be configured such that a notch effect is felt by the external body, the notch effect forming haptic feedback from the interface.

[0038] The process can also be such that: during step a), the external body is electrically conductive and the control member is capable of being contacted, simultaneously, at different contact points, respectively on different conductive elements; during step b), the state signal formed by the sensor is representative of a number of contact points; during step c), the control unit emits an activation signal as a function of a variation in the number of contact points.

[0039] The method may comprise a step e) according to which the control unit addresses a control signal to the device, as a function of the status signal formed by the sensor.

[0040] The external body can be a user's finger.

[0041] The invention will be better understood by reading the description of the exemplary embodiments presented in the remainder of the description, in conjunction with the figures listed below. FIGURES

[0042] THE figures 1A et 1B show an example of a touch interface that looks similar to a control wheel. The figure 1C schematizes a propagation of an ultrasonic vibration through the interface described in connection with the figures 1A et 1B . There figure 1D illustrates a time sequence of transducer activation, generating a vibration of the plate so as to induce a clicking effect. The figure 1E schematizes a movement of a finger along a control organ. During the movement, under the effect of a vibration of the plate, the finger feels the presence of virtual notches on the surface of the control organ. The figures 1F , 1G et 1H respectively illustrate a modulation function, a carrier and an activation signal of the plate resulting from an amplitude modulation of the carrier by the modulation function. The activation signal allows a feeling of virtual notches represented on the figure 1E . There figure 1I shows another activation signal allowing a feeling of the virtual notches represented on the figure 1E . THE figures 2A à 2E represent different configurations of the interface, the latter including characteristics described in relation to the figures 1A à 1I . [ Fig. 3A ] There figure 3A illustrates an activation signal to form an ultrasonic vibration propagating through the interface, under the effect of sliding of an external body, for example a finger, along the control member. The figures 3B et 3C illustrate an activation signal to form an ultrasonic vibration propagating through the interface, under the effect of pressure exerted by an external body, for example a finger, on the control member, towards the plate. The figure 4A illustrates an embodiment according to which an activation signal, allowing the generation of an ultrasonic vibration, is activated according to a variation of a number of contact points on the control member. The figures 4B And 4C show a control organ of parallelepiped and truncated cone shape respectively. The figure 4D shows a possible particular geometric shape of the control organ. The figures 5A à 5D outline the main steps of different usage examples. EXPOSE DE MODES DE REALISATION PARTICULIERS

[0043] THE figures 1A et 1B represent a first example of a touch interface 1 according to the invention. The touch interface is intended to be actuated by an external body 9 so as to control a device 20. The latter may be a processor of a household appliance, or of an automobile equipment, or of any other equipment for general public or professional use. The device 20 is connected to the interface by a wired or wireless link.

[0044] In the examples shown in this application, the external body 9 is a finger, which corresponds to most of the applications envisaged. Alternatively, the external body 9 may be a stylus, or any other means for acting on the interface 1. The term touch interface designates an interface configured to be touched by such an external body 9.

[0045] The touch interface comprises a rigid plate 10 that can be vibrated. The plate 10 extends between an external face 10 e and an internal face 10 i . The external face 10 e is accessible to the finger 9. The internal face 10 i and the external face 10 e preferably extend parallel to each other. The distance between the external face 10 e and the internal face 10 i defines a thickness e of the plate. The thickness e of the plate is dimensioned to allow vibration of the plate 10 according to an ultrasonic vibration, as described below. The thickness e of the plate 10 is preferably less than 10 mm, or even less than 5 mm. The thickness e is adjusted according to the nature of the material and its mechanical properties (rigidity, solidity). It is for example between 1 and 5 mm for glass or a material such as plexiglass.

[0046] In the example shown, the internal face 10 i and the external face 10 e are flat, which corresponds to the simplest configuration to manufacture. The plate extends, parallel to a lateral axis X, along a width l and, parallel to a longitudinal axis Y, along a length L. The length L and the width l can be between 5 cm and a few tens of cm, for example 30 cm, or even more. The lateral axis X and the longitudinal axis Y define a main plane P XY . In other examples, the internal face 10 i and / or the external face 10 e can be curved.

[0047] The plate 10 is formed of a rigid material, such as glass, or a polymer, or wood, or a metal, or a semiconductor, for example silicon. The plate 10 may be transparent or opaque. The plate 10 may comprise opaque portions and transparent portions. The plate may comprise several layers superimposed on each other.

[0048] In this example, the plate 10 is delimited, along the lateral axis X, by a first lateral edge 10 1 and a second lateral edge 10 2 in the vicinity of which transducers 12 are arranged. By in the vicinity is meant at a distance preferably less than 2 cm, on or under the plate 10. Each transducer 12 is capable of being activated by an electrical activation signal, and, under the effect of the activation signal, of exerting pressure on the plate 10 so as to produce a local deformation of the plate, in a direction perpendicular to the plate. When the activation signal is periodic, at an ultrasonic frequency, the deformation of the plate 10 is periodic, which results in the formation of an ultrasonic vibration 19 propagating through the plate. The vibration may in particular be generated by a bending wave propagating through the plate. The bending wave may be stationary or progressive.Also, the activation signal of each transducer can be modulated in time and / or modulated in amplitude. Preferably, the plate is connected to a plurality of transducers 12. The transducers are generally arranged in the vicinity of at least one edge of the plate 10, and preferably in the vicinity of two edges opposite with respect to the lateral axis X and / or the lateral axis Y. The arrangement of the transducers 12 at the edge of the plate 10 is not a necessary condition: the transducers can be arranged in other configurations, for example in the form of a line, in the middle of the plate, or a matrix.

[0049] Each transducer 12 may be a piezoelectric type transducer, comprising a piezoelectric material, for example AIN, ZnO or PZT, arranged between two electrodes. For example, each transducer 12 may be the reference PZT 406. Alternatively, each transducer may be an electromechanical resonator, for example of the MEMS (Micro ElectroMechanical System) type, or of the electrostrictive or magnetostrictive type. The transducers 12 may be such that the piezoelectric material is deposited, in the form of one or more thin layers, in contact with polarization electrodes.

[0050] Each transducer 12 can be assembled against the internal face 10 i of the plate 10 by gluing. The transducers are mechanically connected to the internal face 10 i: They can be directly assembled to the internal face, or be assembled to an intermediate component, preferably rigid, the latter being assembled to the internal face 10 i, so as to allow transmission, to the plate, of the vibration induced by the or each transducer.

[0051] The intermediate component may be metallic. It may for example be a part forming an amplifier, arranged between the plate and a transducer 12 (or each transducer 12), and arranged to amplify the vibration produced by the transducer 12 (or each transducer 12) and transmitted to the plate 10. The intermediate component may form a rigid layer, so as to increase the rigidity of the plate. The intermediate component may be a screen 11, assembled to the plate 10, as described below. The plate 10 may form a protective slab for the screen 11. The screen 11 may be a screen of the LCD (Liquid Crystal Display) or OLED (Organic Light-Emitting Diode) type. The intermediate component may be a multilayer component. It may for example comprise a screen, under which is placed a part forming an amplifier, the transducers being assembled to the amplifier.

[0052] Generally, each transducer 12 is configured to generate an ultrasonic vibration 19, the latter propagating in the plate 10. The frequency of the ultrasonic vibration 19 is preferably between 10 kHz and 200 KHz. It is preferably greater than 20 KHz, so as to address the ultrasonic spectral band and preferably less than 150 kHz. The amplitude of the ultrasonic vibration 19 is generally between 0.1 µm and 50 µm. Schematically shown on the figure 1C , an ultrasonic vibration 19 propagating in the plate 10. In a manner known in the field of haptic feedback interfaces, the vibration of the plate causes a formation of a thin film of air between the plate 10 and the finger 9, (called the "squeeze film effect" in English terminology) which causes a modification of the contact surface between the finger and the plate. By modulating the amplitude of the vibration of the plate, the thickness of the air film varies. This modifies the friction between the plate and the finger, as described in the prior art, which results in an impression of texturizing of the plate when the user's finger moves on the external face 10 e . The ultrasonic vibration 19 may be stationary, but this is not necessary.

[0053] The inventors have arranged a rigid, three-dimensional control member 2 on the plate 10, and more precisely on the external face 10 e of the plate. They have found that an ultrasonic vibration 19, propagating in the plate 10, can also propagate in the control member 2, in particular when it is possible to preserve the vertical displacement of the plate, without significant damping. The ultrasonic vibration 19 can then be felt indirectly by the finger 9, when the latter touches the control member 2. This is an important element of the invention, according to which a haptic effect can be felt not only in contact with the plate 10, but also in contact with a control member 2, preferably rigid, and connected to the plate 10. The fact that the vibration frequency is ultrasonic makes the vibration imperceptible, except by the external body 9 moving on the external face of the plate or on the control member 2.

[0054] The control member 2 can be fixed on the plate 10. It can also be placed temporarily on the plate 10, being removable. In all cases the control member remains fixed during its operation, that is to say during its actuation by an external body.

[0055] The control member 2 may take the form of a conventional control member, as described in the prior art: adjustment wheel, button or slider. However, unlike standard control members, the control member 2 may be a simple, inert element, without moving or electronic parts. It may, for example, be obtained by a simple manufacturing process, for example molding.

[0056] Generally speaking, the control member 2 extends between a proximal end 2 p , in contact with the plate 10, and a distal end 2 d , located at an extension distance from the plate. The extension distance corresponds to a distance, along a transverse axis Z, perpendicular to the plate 10, between the plate and the distal end 2 d . It is typically equal to a few millimeters or centimeters. The control member 2 comprises a lateral face 2 a , connecting the proximal end 2 p to the distal end 2 d . The finger 9 can contact the control member 2 either at the distal end 2 d (cf. figure 1B ) or at the level of the lateral face 2 a (cf. figures 1A, 1B , 1C And 1E ).

[0057] The finger 9 can also contact the control member on its edges (for example at the junction of the lateral face 2 a and the proximal end 2 p ), or on an internal face when the control member is hollowed out, for example in the case of a ring. In the example shown in the figure 1A , the distal end 2 d is surface-like, and extends along a flat surface parallel to the external face 10 e of the plate 10. The distal end 2 d can constitute a support surface for the control member 2.

[0058] The fact that the control member 2 extends in three dimensions improves the gripping of the latter by one or more fingers 9. A finger 9 can slide easily along the lateral surface 2 a, or press on the distal end 2 d in the direction of the plate 10. The three-dimensional surface of the control member 2 also makes it possible to increase a contact surface of the interface. It is understood that the three-dimensional control member 2 makes it possible to obtain an interface 1 whose ergonomics are improved compared to a flat interface.

[0059] In the example shown on the figures 1A à 1C And 1E , the control member 2 has a cylindrical shape, similar to the shape of a wheel. According to other configurations, the control member may have other shapes, for example a parallelepiped, a cone, a truncated cone, or a hemispherical shape. Examples of parallelepiped or truncated cone shapes are discussed below, in connection with the figures 4B à 4D . The control member 2 is rigid. It can be assembled to the external face 10 e of the plate 10 by gluing.

[0060] The interface 1 comprises a sensor 14, making it possible to form a signal S(t), called the state signal, depending on a state of the contact between the finger 9 and the control member 2, at a time t. By state of the contact, we mean: a position of the contact on the control member 2, and / or a variation of said position; and / or a pressure exerted by the finger 9 on the plate 10, via the control member 2, and / or a variation of said pressure.

[0061] The sensor 14 may comprise a position sensor 14 a . The function of the position sensor 14 a is to determine a position of a contact of the finger 9, parallel to the external face 10 e . In the example shown in the figures 1A et 1B , the plate 10 is formed of a dielectric material, and the position sensor 14 a is a capacitive type sensor. It is connected to conductive tracks 13, arranged in a two-dimensional network. The conductive tracks 13 are adjacent to the inner face 10 i . The conductive tracks extend parallel to the plate 10, below the outer face 10 e . In the example shown, the conductive tracks are formed on a capacitive screen 11, and arranged adjacent to the inner face 10 i .

[0062] When the plate 10 is opaque, the conductive tracks 13 can be made from a usual conductive material, for example a metal. When the plate 10 is transparent, the conductive tracks 13 are preferably made from a transparent conductive material, for example a conductive oxide, a usual material being ITO (Indium Tin Oxide). The network formed by the conductive tracks 13 can be matrix-like, the tracks being rectilinear, and extending along rows and columns. The conductive tracks can be polarized according to a polarization voltage.

[0063] The conductive tracks 13 can be formed directly on the plate 10 or in the plate 10.

[0064] The control member 2 may comprise or be formed by a dielectric material, for example a plastic. It may comprise conductive elements 3, for example metallic, and preferably rectilinear, extending from the proximal end 2 p , towards the distal end 2 d , along the lateral surface 2 a . The different conductive elements 3 are electrically insulated from each other. Such a control member 2 may be structured as described in the patent application FR1907542 filed on 05 / 07 / 2019. At the proximal end 2 p , each conductive element 3 is arranged to be placed opposite a conductive track 13, being separated from the latter by a small thickness of dielectric material formed by the plate. A capacitive coupling can then be established between the conductive track 13 and the conductive element 3.

[0065] The finger 9 being electrically conductive, under the effect of proximity to a conductive element 3, a transfer of charges can be carried out, by capacitive effect, between one or more conductive tracks 13 and the finger 9, by means of the capacitive coupling taking place between the conductive element 3 and the conductive track(s) 13. The finger 9 can be in direct electrical contact with a conductive element 3. It can also be in capacitive coupling with a conductive element 3, for example when the conductive element 3 is covered with a thin dielectric layer, for example a varnish. It should be noted that detection by capacitive coupling assumes that the control member 2 is touched by an electrically conductive body 9: finger or conductive stylus, for example metallic.

[0066] On the figures 1A et 1B , the conductive tracks 13 are represented by dashes because they are located behind the plate 10.

[0067] The conductive tracks 13 are connected to the position sensor 14 a . The latter is configured to estimate a position, parallel to the plate 10, of a capacitive contact point between the finger 9 and the conductive tracks 13. Due to the two-dimensional arrangement of the conductive tracks 13, the position sensor 14 a makes it possible to obtain two-dimensional coordinates ( x , y ) of the contact point, parallel to the plate 10. The position sensor 14 also makes it possible to estimate a variation of the contact point, the latter being detected: when the finger 9 moves relative to the control member 2: this is then a spatial variation in the position of the contact point; when a finger 9 is applied to or removed from the control member 2: this is then a temporal variation in the position of the contact point.

[0068] In a manner known in the field of capacitive detection, the conductive tracks 13 and the conductive elements 3 advantageously define a mesh such that the presence of a finger 9 is detected simultaneously by several conductive tracks 13. The finger is thus placed in contact or in capacitive coupling with at least two adjacent conductive elements 3. This makes it possible to obtain a determination of the position of the finger, parallel to the plate 10, according to a high spatial resolution.

[0069] On the figure 1A , a part 11' of a screen 11 is shown, located against the internal face 10i of the plate 10. In this example, the screen 11 makes it possible to display, on the part 11', a parameter 18 whose value is adjusted by the finger 9 acting on the control member 2, as described below.

[0070] There figure 2A represents a view, along a plane P XZ, of the main elements making up the interface 1. In the example shown on the figure 2A , the sensor 14 comprises, in addition to the position sensor 14 a , a pressure sensor 14 b . The pressure sensor 14 b is configured to measure a pressure exerted on the plate 10, and causing a deformation of the latter. In the example shown in the figure 2A , a finger 9 is shown pressing on the control member 2, towards the plate 10. The pressure exerted by the finger 9 is transmitted, by the control member 2, to the plate 10. Under the effect of the pressure, the plate 10 undergoes a deformation, and curves towards the pressure sensor 14 b. In the example shown in the figure 2A , the capacitive screen 11 is pressed against the internal face 10 i of the plate 10. Under the effect of the pressure exerted on the plate 10, the assembly formed by the plate 10 and the screen 11 deforms.

[0071] The pressure sensor 14 b may comprise a rangefinder, configured to measure a variation in distance separating it from the plate 10. The detection range of the rangefinder is then adapted to short distances, and to small variations in distances. It may for example be an infrared optical rangefinder, the operating range of which is between 1 and 5 mm, and arranged 2.5 mm from the plate. Such a rangefinder is usually referred to as a “reflective object sensor”. For example, the reference sensor QRE 1113 is suitable for such an application.

[0072] On the figure 2B , the interface has a position sensor 14 b but no pressure sensor 14 b .

[0073] As an alternative to a telemeter, the pressure sensor 14 b can be a strain gauge, arranged in contact with the plate 10, or the assembly formed by the plate 10 and the screen 11. The strain gauge makes it possible to quantify the deformation of the plate. figure 2C shows such a configuration. Note that in the configuration shown in the figure 2C , the sensor 14 does not include a position sensor 14 a .

[0074] Another alternative is the use of a dynamometric sensor, placed in contact with the plate 10, and allowing a measurement of the pressure applied by the plate. However, for reasons of simplicity of design, the use of a telemeter type sensor is preferred. This allows a contactless measurement of the deformation undergone by the plate 10.

[0075] According to another alternative, the pressure sensor 14 b is as described in patent application EP3566115. The pressure sensor 14 b acts while the plate 10 is vibrated by at least one piezoelectric transducer 12. The pressure exerted on the plate 10 is estimated by measuring a variation in a vibration amplitude under the effect of said pressure. The measurement of the variation in the vibration amplitude can be carried out by one or more transducers 12. From the variation measurements resulting from the transducers 12, the pressure sensor 14 b determines the pressure applied to the plate 10. In such a configuration, the pressure sensor 14 b is connected to transducers 12, as shown in the figures 2D et 2E .

[0076] The interface also comprises a control unit 15, connected to the sensor 14, the latter comprising the position sensor 14 a and / or the pressure sensor 14 b. The sensor 14 sends a status signal S(t) to the control unit 15. The status signal comprises: a position component S a (t), from the position sensor 14 a , representative of a position of the finger, or of several fingers, on the control member 2; and / or a pressure component S b (t), from the pressure sensor 14 b , representative of a pressure exerted by the finger, on the control member 2, towards the plate 10.

[0077] The state signal S(t) is updated at each instant t, according to a measurement frequency which can for example be between a few tens of Hz and a few hundreds of kHz.

[0078] The control unit 15 comprises a microcontroller or a microprocessor. The control unit 15 is configured or programmed to perform the actions described below. Depending on the status signal S(t) transmitted by the sensor 14, the control unit 15 can address a control signal Com(t) to the device 20. For example, when the interface 1 is used to define a value of an operating parameter 18 of the device 20, the control unit 15 is configured to transmit the value of the parameter to said device.

[0079] An important aspect of the invention is that the control unit 15 is configured to address an activation signal Act(t) to at least one transducer 12, and preferably to each transducer 12, as a function of the state signal S(t). The objective sought is to obtain haptic feedback from the interface 1, addressed to the user. Under the effect of the activation signal, each activated transducer generates an ultrasonic vibration 19, propagating through the plate 10 and through the control member 2, to the finger 9 of the user, as shown in the figure 1C .

[0080] There figure 1D illustrates a modulation of the amplitude of the ultrasonic vibration 19 as a function of time, under the effect of the activation of the piezoelectric transducers. The figure 1D corresponds to a generation of a click effect. By click effect, we mean an effect by which the finger, in contact with the control member 2, perceives a haptic sensation of a click, comparable to a click made by acting on a conventional control button, for example by pressing or releasing it. This effect can be obtained by subjecting all or part of the transducers 12 to an activation sequence as shown in the figure 1D . By activation sequence, it is meant a generation of the activation signal Act(t) during a time duration Δt, allowing the plate 10 to vibrate. In this example, the activation sequence extends over a duration Δt = 10 ms. According to other examples, it can last between a few ms, for example 5 ms, and a few hundred ms. The activation of the transducers 12 causes an ultrasonic vibration of the plate 10 according to an amplitude which can be for example equal to 2 µm peak to peak. On the figure 1D , the abscissa axis corresponds to time (unit in seconds) while the ordinate axis corresponds to the amplitude of the activation signal Act(t) addressed to the transducers 12. The unit of the ordinate axis of the figure 1D is the picometer: this represents the amplitude of the deformation of the plate. An activation sequence corresponding to a click can be parameterized by the duration Δt, as well as the amplitude or frequency of the activation signal. By varying one of these parameters, the click effect felt can vary. Thus, the control unit 15 can generate different activation sequences, each activation sequence corresponding to a particular click feeling. According to a variant, the click effect can be produced as described in patent application FR1909660 filed on September 3, 2019. Where the activation sequences can be recorded in a memory 16 connected to the control unit 15.

[0081] In the activation sequence shown in the figure 1D , the activation signal Act(t) is formed by a so-called periodic "carrier" signal w, modulated in amplitude. The period of the carrier signal w preferably corresponds to an ultrasonic frequency, i.e. between 20 kHz and 200 kHz. In this example, the carrier w is sinusoidal. The activation signal is formed by an amplitude modulation of the carrier, by a modulation function A . In the example shown on the figure 1D , the modulation function A is first increasing, then constant, then decreasing. The activation signal is such that: Act t = A t × w t

[0082] During carrier modulation, the modulation function A takes a predetermined time form: it can be a simple gate function, or trapezoidal, or Gaussian, or triangular or other type of periodic function.

[0083] According to another embodiment, the finger 9 perceives a notch effect when it slides along the control member 2. On the figure 1E , virtual notches C have been shown along the lateral surface 2 a of the control member 2. The notches C are virtual: they do not correspond to a real texturing or a surface condition of the control member 2. These are notches felt by the finger sliding along the surface 2 a , under the effect of a vibration of the plate and the control member. For example, the surface of the control member is smooth and the finger, sliding on the control member, perceives a virtual texturing corresponding to notches spaced from each other. By notch effect, we mean an effect by which the finger, when sliding along the control member 2, feels a haptic sensation of notches, comparable to a passage of mechanical notches that is perceived by turning an adjustment wheel. In other words, it is about mimicking a sensation of notches that the finger would perceive if it acted on a notched mechanical cursor.This results in a near-instantaneous variation in the speed of the finger as it moves through each notch. The variation in the speed of the finger corresponds to an acceleration or deceleration. The variation in speed is induced by a variation in the friction of the finger sliding along the interface. The variation in friction is obtained by vibrating the plate, as detailed below.

[0084] Similar to the click effect, the activation signal is obtained by amplitude modulation of a periodic carrier w. Amplitude modulation is performed by an amplitude modulation function. Unlike an activation sequence corresponding to a click, the amplitude modulation function is periodic when one wishes to obtain a feeling of several successive notches.

[0085] According to a first possibility, represented on the figures 1F à 1H , the modulation function Ais increasing triangular. The figures 1F , 1G et 1H respectively represent a modulation function A , a sinusoidal carrier w , and the activation signal Act resulting from a sinusoidal carrier amplitude modulation by the modulation function, according to expression (1).

[0086] In each of these figures, the abscissa axis corresponds to time t (unit: second) and the ordinate axis corresponds to the amplitude.

[0087] We observe that the temporal form of the modulation function A includes, for each notch: an anterior temporal phase dt a , occurring when the finger approaches the notch; a notch temporal phase dt c , occurring when the finger crosses the notch; a posterior temporal phase dt p , occurring when the finger moves away from the notch.

[0088] The anterior, notch, and posterior temporal phases are activated successively. They define an activation sequence associated with the notch. Thus, for each notch, the activation signal forms an activation sequence, corresponding to the succession anterior phase, notch phase, posterior phase. The duration of an activation sequence corresponds to the sum of the respective durations of the anterior, notch, and posterior phases.

[0089] Generally speaking, each activation sequence corresponding to a notch is such that during the notch phase, the amplitude of the modulation function Avaries within a significantly greater variation range than in the anterior and posterior phases of the sequence. The modulation amplitude conditions the friction of the finger on the surface of the control member 2. The perception of a notch is realistic when before and after the notch, the friction is relatively stable, and when the notch is passed, the friction varies significantly. This results in a sudden variation in the speed of the finger when the notch is passed, which leads to a perception of a notch by the user. The sudden variation in speed can be a deceleration, an acceleration, or an acceleration / deceleration combination. During the anterior and posterior phases preceding and following a notch, the variation in the modulation amplitude is less than during the notch phase. During the anterior and posterior phases, the modulation amplitude can be stable, for example zero, as shown in the figures 1F And 1H, without this being necessary. A stable modulation amplitude generates a sensation of flatness of the surface of the control organ 2 before or after the passage of a virtual notch C.

[0090] So, if Δ A ( t ) corresponds to the variation of amplitude, a time sequence of notch can be such that: max dt c Δ A t > max dt a , dt p Δ A t

[0091] In the example of the figures 1F And 1H , during the notch phase dt c , the modulation amplitude of the plate is progressively increased, which leads to an increasing perception of sliding: the speed of the finger increases. The notch phase ends with a break, causing a sudden slowing of the finger. The acceleration / deceleration combination induces a perception of a notch.

[0092] A time sequence corresponding to a notch is preferably such that during the notch phase, the absolute value of the time derivative A' ( t) of the modulation function has a higher maximum value than during the earlier and later phases. If A ( t ) corresponds to the modulation function: max dt c A ′ t > max dt a , dt p A ′ t

[0093] This reflects the fact that during the notch phase, the modulation function undergoes a higher and / or faster amplitude variation than during the anterior and posterior phases. This results in a faster and / or more significant variation in friction, inducing a perception of a notch at the finger level.

[0094] Two notch phases, corresponding to two successive notches, are temporally spaced by a period dt. The period dt is adapted according to a variation in the position of the finger 9 along the control member 2. For example, the period dt is shorter the higher the speed of movement of the finger: this results in a sensation, at the user's finger, of temporally close notches. Thus, depending on the speed of the finger, the period dt of the modulation function is adjusted, in order to improve the realism of the perception of the notches.

[0095] The shape of each virtual notch and the spacing between each virtual notch are predefined digitally, in the memory 16 connected to the control unit 15. By shape of a notch, we mean a shape felt by the finger during the activation sequence corresponding to the notch. On the same control member, depending on the parameter 18 whose value we wish to adjust, the number of notches can be variable. As well as the spacing between successive notches, the latter not necessarily being regular. Also, the memory 16 connected to the control unit 15 can include, for the same control member, a library of virtual textures, each texture corresponding to a shape and a distribution of notches on the control member 2.

[0096] In addition to the time period between two successive notches, it is possible to modulate the notch sensation perceived by the finger. figure 1I shows another example of an activation sequence allowing the feeling of another notch effect, different from the notch effect obtained according to the sequence represented on the figure 1H . On the figure 1I , the carrier is identical to the carrier shown on the figure 1G The modulation function is decreasing triangular.

[0097] Other activation sequences producing a notch signal are conceivable, for example with a modulation function whose temporal form includes square waves or has a sinusoidal shape. This makes it possible to obtain a wide variety of notch sensations at the level of the finger 9. For example, notches can be obtained generating a perception of progressively increasing resistance. A notch sequence is parameterized by the frequency and / or the shape of the carrier and / or the shape and / or the amplitude of the modulation function. The modulation function Acan be composed of several elementary components allowing the creation of more complex effects.

[0098] The generation of a click effect, as described in connection with the figure 1D , is generally carried out by addressing an uninterrupted activation sequence, of duration Δt, under the effect of pressure from the finger (or more generally from the external body 9) on the control member 2. By uninterrupted activation sequence, we mean an activation sequence extending between an initial instant and a final instant, without interruption.

[0099] In a variant described in connection with the figure 4A , the click effect can be activated when the number of fingers contacting the control organ 2 varies.

[0100] Alternatively, the method may generate two or more successive clicks in close succession, each click being spaced from another click by a short duration, while the finger maintains pressure. The activation sequence corresponding to all the clicks may preferably have a total duration of less than 10 ms.

[0101] In the example shown on the figure 2A , the control member is stationary relative to the plate 10. It does not have any components that are movable relative to the plate 10. The same applies to the control member shown in the figures 2B à 2E This corresponds to a particularly simple mechanical design of the interface.

[0102] In the example shown on the figure 2B , the sensor 14 does not include a pressure sensor 14 b: the state signal S(t) addressed to the control unit 15 only includes a component S a (t) representative of the position of a contact of the finger 9 on the control member 2.

[0103] The control body 2 shown on the figure 2C is particularly simple, since it does not include electrical conductors 3 extending from the proximal end 2 p . In the example shown schematically on the figure 2C , the sensor 14 does not include a position sensor 14 a: the state signal S(t) addressed to the control unit 15 only includes a component S b (t) representative of the pressure exerted by the finger 9 on the control member 2.

[0104] The screen 11 can be arranged at a distance from the interface 2. This scenario is shown in the figure 2D , on which the screen is integrated into the device 20 controlled by the interface 1, remotely from the latter.

[0105] In the example shown on the figure 2E , the interface 1 comprises a screen 11 occupying only part of the surface of the plate 10.

[0106] We will now describe examples of using interface 1. Premier exemple d'utilisation

[0107] According to a first example of use, interface 1 is as shown in the diagrams figures 1A, 1B , 1C , 1E And 2A . The control unit 15 receives a status signal S(t) comprising a position component S a (t) and a pressure component S b (t). The user's finger 9 can slide around the control member 2, as shown in the figures 1A , 1C And 1EThe presence of the conductive elements 3, capacitively coupled to the conductive tracks 13, makes it possible to determine the position of the finger 9 on the control member 2. Depending on the position of the finger, or a variation in the position of the finger, the control unit 15 sends an activation signal Act(t) to each transducer 12, so as to form an ultrasonic vibration 19, modulating a friction of the finger 9 with the surface of the control member 2. This results in an impression of increased or decreased roughness. The user thus feels a notch effect provided by the modulation of the friction. The modulation of the friction depends on the activation signal controlling the transducers 12. In order to obtain a notch effect, the activation signal may be as described in connection with the figures 1E à 1I .

[0108] According to one possibility, from the position component S a (t), the control unit 15 determines a position of the finger relative to predetermined positions. The control unit 15 addresses an activation sequence of the “notch effect” type, as described in connection with the figures 1E à 1I , so as to induce a notch sensation when the finger passes over a determined position. In the memory 16 connected to the control unit 15, each of said predetermined positions corresponds to a virtual notch C.

[0109] Alternatively, from the position component S a (t), the control unit 15 determines a variation in the position of the finger, and for example a speed of movement of the finger along the control member 2. The activation signal can be parameterized as a function of the movement speed. For example, the higher the movement speed, the more the period dt of the activation signal decreases. The figure 3A represents a variation of an activation signal as a function of a finger movement speed. During a first time interval T1, the finger slides along the control member 2 at a certain speed. During a second time interval T2, subsequent to the time interval T1, the finger slides along the control member 2 at a higher speed. This results in a modification of the activation signal. Thus, the activation signal, and in particular its period dt, can be modified as a function of the speed of the finger along or around the control member 2.

[0110] As previously indicated, when the finger 9 slides along the control member 2, the control unit 15 generates a notch effect. The notch effect mimics a notch sensation, which would be obtained by moving a notched mechanical wheel.

[0111] When the finger 9 presses against the distal end 2 d , in the direction of the plate 10, the pressure component S b (t) is representative of the increase in the pressure exerted. When a pressure threshold P 1 , called the first depression threshold, is reached, the control unit 15 sends a control signal Act(t) to the transducers, so that the latter generate an ultrasonic vibration, according to an activation sequence as described in connection with the figure 1D . The duration Δt of the activation sequence may be, for example, between 1 ms and 1 s, and preferably between 1 ms and 100 ms. The ultrasonic vibration 19 propagates to the control member 2 where it is felt indirectly by the user's finger 9. The activation sequence forms a click effect, felt by the user. The click effect produced by the interface mimics a mechanical click effect felt when a finger presses a conventional mechanical button. When the click effect is felt by the user, the user can then release the pressure.

[0112] Optionally, under the effect of a release of the user's finger, when the pressure applied to the plate 10 decreases and goes below a release threshold P 2 , the control unit 15 can send an activation signal to the transducers 12, so as to form a second click effect, similar to or different from the click effect generated when crossing the first depression threshold P 1 . On the figure 3B , we have represented a change in the pressure exerted on the plate as a function of time, as well as the vibration amplitude of the plate as a function of time. At a time t 1 , the pressure exerted exceeds the depression threshold P 1 , which leads to the generation of a click effect. The release threshold P 2 is crossed at a time t 2 . In this example, the vibration amplitude A of the plate, when crossing the release threshold, is lower than the vibration amplitude of the plate when crossing the first depression threshold P 1 . According to alternatives, the duration Δt of each activation sequence is adjustable: it can be longer when crossing the first depression threshold P 1 and shorter when crossing the release threshold P 2 , or vice versa.

[0113] Thus, in order to trigger an activation sequence generating a click effect, the control unit 15 can take into account not only the level of pressure exerted on the plate, but also the direction of variation, increasing or decreasing, of the pressure level. The triggering of the depression threshold can be carried out while the pressure exerted is increasing, while the triggering of the release threshold is carried out while the pressure exerted is decreasing.

[0114] Optionally, multiple sinking thresholds can be defined. This is illustrated in the figure 3C : a second depression threshold P' 1 is defined. When the second depression threshold P' 1 is crossed, at time t' 1 , while the pressure exerted on the plate increases, the control unit 15 can command an activation sequence of the transducers 12 different from the activation sequence triggered when the first depression threshold P 1 is crossed. In the example shown in the figure 3C , the vibration amplitude corresponding to the second depression threshold P' 1 is greater than the vibration amplitude corresponding to the first depression threshold P 1 . The number of different depression thresholds may be greater than 2.

[0115] An example of application of such an embodiment corresponds to the adjustment of a value of a parameter 18, then the validation of the selected value. The finger 9 can slide around the lateral face 2a of the control member 2. Depending on the evolution of the position of the finger relative to different conductive elements 3, the control unit 15 determines a direction of rotation of the finger. Depending on the direction of rotation, and possibly the speed of rotation, the value of the parameter 18 is either increased or decreased, by one or more increments. The control unit 15 defines the relationship between the position of the finger (and / or the speed of the finger) and the passage of an increment of the parameter. The value of the parameter 18 can be displayed on a part 11' of the screen 11, as shown in the figure 1A .

[0116] The haptic feedback generated by interface 1 allows the user to feel each increment, allowing for precise adjustment of parameter 18. The haptic feedback corresponds to a notch effect, as described in connection with the figures 1E à 1I as well as with the figure 3A . When an increment is crossed, the control unit 15 sends a control signal Com(t) to the device 20, so as to modify the value of the parameter by an increment.

[0117] In order to confirm a selected value of a parameter, the finger 9 presses the distal end 2 d towards the plate 10. The resulting click effect informs that the selected value is validated. When the user's finger 9 presses the control member 2, the pressure increases progressively, up to a first depression threshold P 1 , as described in connection with the figure 3B . The pressure exerted is detected by the pressure sensor 14 b. The control unit 15 then generates an activation signal controlling an activation sequence of the transducers 12. This activation sequence is representative of a click effect. The haptic feedback generated by the interface allows the user to feel the click effect. He is then informed that his pressure action has been taken into account by the interface 1. The control unit 15 also sends a control signal Com(t) to the device 20, so as to validate the value of the parameter selected by the user.

[0118] According to another example of application, when the finger moves along the control member 2, the screen 11 displays different options, according to a so-called navigation mode. At each increment, a new option is proposed. When the user wishes to keep an option, he validates the proposed option by pressing his finger 9 on the distal end 2 d.

[0119] The main steps of this first example of use are summarized on the figure 5A .

[0120] Step 100: detecting a position of a contact point on the control member 2, using the position sensor 14 a.

[0121] Step 110: when a change in the position of a contact point has been detected, triggering, by the control unit 15, of an activation signal Act(t) of the transducers 12, according to one or more activation sequences representative of a notch effect.

[0122] Step 120: when a change in the position of a contact point has been detected, triggering, by the control unit 15, of a control signal Com(t) to the device 20, so as to adjust a parameter 18, or a value of the parameter 18.

[0123] Steps 110 and 120 may be implemented simultaneously.

[0124] Step 130: detection of pressure exerted on the plate by the control member 2, using the pressure sensor 14 b.

[0125] Step 140: when the pressure exerted increases and crosses the first depression threshold P 1 , triggering, by the control unit 15, of an activation signal Act(t) of the transducers 12, according to an activation sequence representative of a click effect.

[0126] Step 150: when the pressure exerted increases and crosses the first depression threshold P 1 , triggering, by the control unit 15, of a control signal Com(t) to the device 20, so as to validate the selected parameter 18.

[0127] Steps 140 and 150 may be implemented simultaneously.

[0128] Step 160 (optional): when the pressure exerted increases and crosses the second depression threshold P' 1 , triggering, by the control unit 15, of a control signal Com(t) to the device 20, so as to carry out a complementary action, for example a cancellation of the validation of the parameter. At the same time, an activation signal Act(t) is sent to the transducers 12, according to a sequence of activation of a click effect corresponding to a second depression threshold. The click effect corresponding to the second depression threshold may be similar to the click effect corresponding to the first depression threshold or different.

[0129] Step 170 (optional): when the pressure exerted decreases and crosses the release threshold P 2 , triggering, by the control unit 15, of an activation signal Act(t) of the transducers 12, according to an activation sequence representative of a click effect corresponding to a release of the pressure. This click effect may be similar or different from the previous click effects. Deuxième exemple d'utilisation.

[0130] According to a second example of use, described in connection with the figure 2B , a notch effect, as previously described, is generated when the user's finger slides along the control member 2, interacting with different conductive elements 3, as described in connection with the first example of use. This results in haptic feedback from the interface by notch effect.

[0131] According to this example, the interface 1 does not include a pressure sensor 14 b . The user can move one or more fingers 9 on the side wall 2 a , so as to slide successively in front of different conductive elements 3. Such contact is detected by the position sensor 14 a .

[0132] This results in haptic feedback from the interface through a notch effect, as described in connection with the first use case.

[0133] An example of application may be the adjustment of a value of a parameter when the finger 9 slides along the control member 2, as described in the first example of use. During the adjustment, the control unit 15 sends a control signal Com(t) to the device 20, representative of an adjustment of the value of the parameter.

[0134] The main steps of this second use case are summarized on the Figure 5B. Steps 100 to 120 are described in the first usage example. Third example of use

[0135] According to a third example of use, described in connection with the Figure 2C , the interface 2 does not include a position sensor 14 a . When the finger 9 presses against the distal end 2 d , in the direction of the plate 10, the pressure component S b (t) is representative of the increase (or decrease) in the pressure exerted by the finger 9. The activation signal sent by the control unit 15 to the transducers 12 depends on the pressure level and the direction of variation of said pressure, as described in connection with the first example of use as well as on the Figures 3B and 3C .

[0136] The main steps of this third use case are summarized on the Figure 5C . These steps are described in the first usage example. Fourth example of use

[0137] According to a fourth embodiment, described in connection with the Figure 4A , the interface comprises a position sensor 14 a , and possibly a pressure sensor 14 b . According to this example, from the component S a (t) transmitted by the position sensor 14 a , the control unit 15 generates haptic feedback depending on a number of contact points identified by the position sensor, the number of contact points increasing or decreasing. On the Figure 4A , a first finger 9 and a second finger 9' are shown. The control unit 15 can send an activation signal to the transducers 12 when the number of contact points on the control member 2 is modified.

[0138] For example, as previously described, when a single finger slides along the control member 2, the control unit 15 sends an activation signal corresponding to a notch effect. This phase may correspond to the adjustment of a value of a parameter.

[0139] When a second finger is applied to the control member, the position sensor detects two contact points. In this case, the control unit 15 sends an activation signal corresponding to a click effect, different from the notch effect. This phase may correspond to the validation of the selected parameter value.

[0140] In such an example of use, the adjustment of the parameter value is carried out as described in connection with the first example of embodiment. The validation of the parameter is carried out not by applying pressure, but by changing the number of contact points on the control member, by increasing or decreasing the number of contact points.

[0141] The main steps of this fourth use case are similar to those described in connection with the Figure 5D . In addition to steps 100, 110, and 120 described in connection with the Figure 5A, this usage example includes the following steps: Step 135: when the position sensor detects a variation in the number of contact points, the control unit 15 addresses an activation signal Act(t) to the transducers 12, according to an activation sequence representative of a click effect. Step 145: when the position sensor detects a variation in the number of contact points, the control unit 15 also addresses a control signal Com(t) to the device 20, so as to validate the selected parameter 18. Variants

[0142] In the preceding examples, the control member 2 has a cylindrical shape. As previously indicated, other shapes can be envisaged. In the example shown in FIG. 4B, the control member 2 has a parallelepiped shape. Different conductive elements 3 are spaced from each other, along the lateral axis X. The user's finger can slide along the lateral surface 2 a or the distal end 2 d of the control member, so as to successively contact different conductive elements 3, as previously described. This allows for example an adjustment of a value of a parameter, as explained in connection with the first, second, and fourth examples of use. The movement of the finger is detected by a position sensor 14 a.

[0143] According to this variant, the interface 1 may comprise a pressure sensor 14 b, so as to detect pressure exerted on the control member 2, towards the plate 10.

[0144] Such a variant is compatible with the fourth example of use, in which the control unit can take into account a variation in the number of contact points on the control member 2.

[0145] In the example shown in the Figure 4C , the control organ 2 has a truncated cone shape.

[0146] On the figure 4D, a control member 2 is shown whose geometric shape is particularly suitable for an implementation of the invention. The control member 2 extends, from the distal end 2 d , in a cylindrical shape. Then, it flares out to the proximal end 2 p , forming a skirt. When the finger or fingers 9 are applied at the interface between the cylindrical part and the skirt, the contact surface of the finger or fingers on the control member 2 is increased. This results in a better feeling of the haptic feedback. In addition, this flared shape has the advantage of reducing direct contact between the end of the finger or fingers 9 and the plate 10 when gripping the control member 2, this direct contact being able to interfere with the recognition of the position of the finger or fingers or their movement on the control member 2.

[0147] The interface according to the invention can be controlled using a user's finger, or using any other external body 9 allowing contact with the control member 2. When the position sensor implements capacitive detection, the external body is electrically conductive.

[0148] The interface is suitable for controlling consumer devices, for example in the field of household appliances. It allows, for example, controlling an oven temperature or a washing machine program, while using robust control elements that are simple and inexpensive to manufacture. Indeed, each control element may have no moving parts. The interface allows for haptic feedback, perceptible to the user. Preferably, the haptic feedback mimics a mechanical response from a moving mechanical element. This makes the interface simple and user-friendly to use.

[0149] The interface is particularly suitable for controlling a device when the user's visibility is reduced or when the interface is located outside the user's field of vision. This is the case, for example, when the user is a driver of a car or an aircraft pilot. He can easily find and take control of the control member 2, because the latter extends along a three-dimensional volume. Il There is therefore no need to divert attention and visualize the control organ. The latter can be easily manipulated while being outside the user's field of observation. This is a notable difference with a conventional touch screen.

[0150] The interface combines the ease of handling and use of a mechanical control device, while allowing the modularity permitted by a touch screen: choice of different menus, adjustment and selection of different parameters. Haptic feedback provides user assistance, ensuring that the user's action on the control device is taken into account. The user can then manipulate the interface without having to change their field of observation.

[0151] The interface 1 takes advantage of the ability to generate a wide variety of activation signals, allowing generation of as many different click and / or notch effects. And this is done using a device of very simple mechanical design, since the control member 2 can remain static relative to the plate 10, and can have no moving parts. This results in an interface whose manufacturing cost is low, as is mechanical wear, due to the absence of moving parts in the control member 2.

[0152] Another advantage is that the modification of the feeling of the haptic feedback can be obtained by a simple configuration of the activation signal. To this end, the control unit 15 can be the subject of specific programming, so as to adapt to a particular use. A modification of a feeling can be obtained with the same control member 2 by only requiring a modification of the programming or of the memory connected to the control unit.

Claims

1. A touch interface (1), intended to control a device (20), the interface being intended to be touched by an external body (9), and comprising: - a plate (10); - at least one transducer (12), configured to vibrate the plate (10) at an ultrasonic vibration frequency; the interface being characterized in that it comprises: - a control member (2), extending from the plate, between a proximal end (2p), applied against the plate, and a distal end (2d), located at a distance from the plate, the control member being intended to be in contact with the external body, the control member being configured to be stationary with respect to the plate when it is actuated by the external body; - a sensor (14), configured to emit a state signal (S(t)), the state signal being representative of contact of the external body on the control member; - a control unit (15), connected to the sensor (14), and configured to send, on the basis of the state signal, an activation signal (Act(t)) to said at least one transducer, so as to vibrate the plate and the control member, such that, under the effect of the ultrasonic vibration of the control member, a friction of the external body with respect to the control member is modified, leading to haptic feedback from the interface.

2. The interface as claimed in claim 1, wherein the control unit (15) is configured to send a control signal (Com(t)) to the device (20) on the basis of the state signal (S(t)).

3. The interface as claimed in either one of claims 1 and 2, wherein the control member (2) is fixed against the plate (10).

4. The interface as claimed in any one of the preceding claims, wherein: - the sensor (14) comprises a pressure sensor (14b), configured to measure a pressure exerted by the control member (2) on the plate (10), the state signal comprising a pressure component (Sb(t)), depending on the exerted pressure; - the control unit (15) is configured to send an activation signal (Act(t)) to the transducer when the pressure crosses a predetermined threshold (P1, P'1, P2) or on the basis of a pressure variation.

5. The interface as claimed in claim 4, wherein the pressure sensor comprises: - a rangefinder, arranged facing the plate, and configured to measure a distance (d) separating it from the plate, the rangefinder being configured to determine a deformation of the plate under the effect of a pressure exerted on the plate; - or a strain gauge designed to deform under the effect of a deformation of the plate under the effect of a pressure exerted on the plate; - or a dynamometer, arranged in contact with the plate, and configured to detect a movement of the plate under the effect of a pressure exerted on the plate; - or a transducer, configured to measure a variation in a vibration of the plate, the variation resulting from a pressure exerted on the plate.

6. The interface as claimed in either one of claims 4 and 5, wherein, depending on the pressure component measured by the pressure sensor (14b), the control unit (15) is configured to send an activation signal that takes the form of an activation sequence, the activation sequence being parameterized such that a clicking effect is felt by the external body, the click forming haptic feedback from the interface.

7. The interface as claimed in any one of the preceding claims, wherein: - the sensor (14) comprises a capacitive position sensor (14a), connected to a network of conductive tracks (13) extending parallel to the plate; - the control member (2) is formed of an electrically insulating material, and comprises conductive elements (3), electrically insulated from one another, extending between the proximal end (2p) and the distal end (2d); - at least one conductive track (13) is arranged in capacitive contact with at least one conductive element (3) of the control member, so as to allow a charge transfer, through a capacitive effect, between the external body (9) and the conductive track, by way of the conductive element; such that the state signal (S(t)) comprises a position component (Sa(t)), depending on a position of the contact between the external body and the control member.

8. The interface as claimed in claim 7, wherein the control unit (15) is configured to send the activation signal (Act(t)) to the transducer when the position component undergoes a variation representative of a variation in the position of the contact between the external body and the control member.

9. The interface as claimed in either one of claims 7 and 8, wherein, depending on the position component measured by the position sensor (14a), the activation signal (Act(t)) is parameterized such that a notch effect is felt by the external body, the notch effect forming haptic feedback from the interface, the notch effect corresponding to the external body feeling at least one virtual notch on the control member.

10. The interface as claimed in claim 9, wherein the activation signal is established from: - a periodic carrier (w), the carrier extending, in each period, over an amplitude; - a modulation function (A), varying on the basis of the position component; such that the amplitude of the activation signal results from a modulation of the carrier (w) by the modulation function (A).

11. The interface as claimed in claim 10, wherein the modulation function successively comprises: - an anterior phase (dta), when the external body approaches a notch; - a notch phase (dtc), when the external body crosses the notch; - a posterior phase (dtp), when the external body moves away from the notch; such that the feeling of the virtual notch by the user depends on the modulation function during the anterior, notch and posterior phases; the modulation function being such that, in the notch phase : - the modulation function varies over a wider range of variation than in the anterior phase and in the posterior phase; or - the modulation function is such that an absolute value of its time derivative (|A'(t)|) reaches a higher maximum value than in the anterior phase and in the posterior phase.

12. The interface as claimed in any one of the preceding claims, wherein the control member (2) does not comprise any component that is mobile with respect to the plate (10).

13. The interface as claimed in any one of the preceding claims, wherein the control member (2) has the geometric shape of a button or a control wheel or a slider.

14. A device (20), able to be controlled by a parameter (18), and comprising an interface (1) configured to select the parameter or set a value of the parameter, the device being characterized in that the interface is an interface as claimed in any one of claims 1 to 13, the interface being configured to determine the value of the parameter or to select the parameter on the basis of the state signal (S(t)).

15. A method for controlling an interface as claimed in any one of claims 1 to 13, comprising: a) applying an external body (9) to the control member (2); b) the sensor (14) forming a state signal (S(t)), representative of a position of the external body on the control member and / or of a pressure exerted by the control member on the plate, under the effect of the external body; c) the control unit emitting, on the basis of the state signal, an activation signal (Act(t)) for the transducer (12) or for each transducer; d) under the effect of the activation signal, vibrating the plate, such that an ultrasonic vibration propagates through the control member (2), so as to bring about a haptic effect on the external body (9).