Flexible haptic interface

Abstract

A flexible haptic interface (1) comprising a haptic structure (2) defining a touch surface (S) that is touchable by a user, the haptic structure comprising a plurality of rigid touch pixels (3) carried by a flexible carrier (4), and at least one actuator (5) in contact with each pixel (3) and arranged to transmit to the pixel (3) a mechanical excitation that results in an effect that is haptically perceptible by the user.

Description

Technical Field

[0001] This invention relates to human-computer interfaces, and more specifically to human-computer interfaces that produce tactile effects. Background Technology

[0002] Haptic interfaces allow users to interact with their environment through touch. Currently, haptic effects are increasingly used in many applications, such as smartphones, where smartphones produce slight vibrations when buttons on the screen are pressed to simulate the sensation of pressing a button. Haptic applications also exist in virtual or augmented reality devices, particularly for better immersion in video games. Haptic interfaces, such as touch panels, which produce haptic effects on touch surfaces when a user touches them, are especially well-suited for integration into many technologies such as desktop or laptop computers, tablets, and / or smartphones.

[0003] It is known that ultrasonic transducers, which emit ultrasonic waves that propagate on rigid touch surfaces, can produce a variety of relatively complex tactile effects on rigid touch surfaces.

[0004] With the emergence of flexible commercial products such as foldable smartphones or even rollable televisions, there is a desire to provide flexible tactile interfaces that can be integrated into such products.

[0005] However, the use of simple flexible carriers to support ultrasonic transducers is limited because the waves emitted by the ultrasonic transducers are partially absorbed by the flexible materials; the resulting tactile effect is also difficult for users to perceive by applying pressure to such carriers with their fingers or hands.

[0006] Furthermore, it is known to use pneumatic actuators to generate tactile effects on flexible structures. Patent US10240688B2 discloses a flexible tactile interface that includes pneumatic actuators that allow for the generation of topological effects.

[0007] The paper by Yu et al., “Skin-integrated wireless haptic interfaces for virtual and augmented reality” (Nature, 2019), discloses a flexible haptic interface that includes magnetic actuators that allow for a variety of haptic effects. However, the spatial resolution of the haptic effects obtained using this interface is relatively low, and the use of magnetic actuators results in high power consumption.

[0008] Finally, non-Newtonian fluids have been used to create simple tactile effects, such as button effects and embossed effects. Lochtefeld's paper "Towards real organic user interfaces—using non-Newtonian fluids for self-actuated displays" (CHI13 workshop, 2013) describes a tactile device that uses a shear-thickened non-Newtonian fluid sandwiched between two flexible sheets located on a fixed array of speakers. As sound waves propagate through the fluid and harden locally, a finger-perceptible topology is created.

[0009] The article "Static and dynamic studies of electro-active polymer actuators and integration in a demonstrator" by Poncet et al. (Actuators Journal, 2017) describes a device incorporating piezoelectrically active polymer actuators arranged to create vibratory tactile buttons based on flexible membranes. These buttons are supported by a rigid carrier. Summary of the Invention

[0010] There is a need to further improve flexible haptic interfaces, especially to provide a touch interface that can produce a variety of haptic effects and has good spatial resolution.

[0011] The present invention aims to meet this need, and according to its first aspect, the present invention meets this need by means of a flexible tactile interface comprising a tactile structure defining a touchable surface that is tactile to a user, the tactile structure comprising:

[0012] Multiple rigid touch pixels supported by a flexible carrier

[0013] At least one actuator that contacts each pixel and is arranged to transmit a mechanical excitation to the pixel that results in an effect that can be perceived by the user through touch.

[0014] The present invention provides a tactile structure with a certain degree of flexibility, while still producing a satisfactory tactile effect, and has spatial resolution and reliability suitable for many applications.

[0015] The interface may include any control circuitry configured to modulate signals sent to the actuator to mechanically cause the pixels to vibrate and produce a corresponding tactile sensation on the touch surface.

[0016] Touch pixels

[0017] This invention is not limited to touch pixels having a specific shape. However, certain shapes may be helpful in manufacturing. Therefore, at least some pixels, and more preferably all pixels, can have an overall shape that is polyhedral, and preferably parallelepiped. Pixels can in particular take the form of rectangular flat plates.

[0018] At least some pixels, more preferably all pixels, are preferably made of a relatively hard and common material, such as glass, and more preferably borosilicate glass.

[0019] At least some pixels, more preferably all pixels, preferably have a substantially constant thickness, preferably between 50 micrometers and 5 mm, and more preferably between 200 micrometers and 700 micrometers.

[0020] All pixels can be identical. As a variation, touch pixels of different sizes can be combined within the same interface, for example, depending on their position relative to the touch surface, or depending on the application.

[0021] carrier and integration of touch pixels

[0022] "Carrier" refers to any single-layer or multi-layer structure that ensures the touch pixels remain in place within the tactile structure and the cohesion of the touch pixels within the tactile structure.

[0023] The carrier is preferably formed of one or more polymer materials, which may help to manufacture and achieve the flexibility sought by the tactile structure.

[0024] The pixels are advantageously made of a material that is harder than the material of the carrier. The ratio of the Young's modulus of each touch pixel to the Young's modulus of the carrier is, for example, greater than or equal to 8, more preferably greater than or equal to 20, even more preferably greater than or equal to 50, more preferably between 80 and 90, and especially equal to about 85.

[0025] The choice of carrier thickness can depend on its flexibility: the softer the carrier, the greater its thickness can be, while allowing the desired flexibility to be maintained.

[0026] Depending on the structure of the carrier, touch pixels can be integrated into the carrier in various ways.

[0027] The carrier may specifically include a carrier layer and a compensation layer for compensating for pixel thickness. The compensation layer is located between pixels and above the carrier layer.

[0028] The carrier layer can also act as a protective layer, protecting the touch pixels and / or the actuators equipped with the touch pixels.

[0029] Preferably, the carrier layer has a substantially constant thickness, preferably between 50 nm and 500 μm, and more preferably between 25 μm and 80 μm, for example 50 μm.

[0030] The carrier layer can independently ensure that touch pixels remain in place within the haptic structure. The thickness compensation layer can also work in conjunction with the carrier layer to perform this function.

[0031] Touch pixels can all be located on the same side of the carrier layer, and the compensation layer includes flexible segments extending between the pixels, also known as "flexible bridges" or "flexible hinges".

[0032] The compensation layer preferably has a substantially constant thickness, preferably between 100 μm and 5 cm, and more preferably between 500 μm and 5 mm, for example, 1 mm.

[0033] At least some, and preferably all, touch pixels may have an outer surface that appears on the touch surface.

[0034] The outer surface of the touch pixel can be flush with the outer surface of the compensation layer, and the outer surface of the pixel and the outer surface of the compensation layer then define a substantially smooth surface that can be used as the touch surface of the interface.

[0035] Then, when the user touches the touch surface with their finger, the user directly contacts the touch pixels.

[0036] As a variation, the touch pixels and compensation layer can be covered with a protective layer, which may be the same as or different from the carrier's substrate layer. This protective layer is relatively thin to avoid excessively affecting the perception of touch effects.

[0037] The carrier may include a housing in which the touch pixels are at least partially located, the touch pixels being continuously covered, for example, by a flexible sheet defining a touch surface.

[0038] In one example of the implementation, the carrier includes a receiving layer for receiving touch pixels, the receiving layer forming, for example, a basin-shaped shell, and the carrier also includes a covering layer for covering the pixels, the covering layer being defined, for example, by the aforementioned flexible sheet.

[0039] The overlay layer, in particular, allows for increased external uniformity of the touch surface and avoids parasitic touch sensations that might be felt if the user directly touches pixels and / or adjacent areas, as these parasitic touch sensations can form when touching an uneven surface.

[0040] arrangement of touch pixels

[0041] Touch pixels can be distributed on the carrier in various ways, depending on the application.

[0042] The spacing between two adjacent touch pixels is preferably between 10 micrometers and 5 mm, and more preferably between 1 mm and 2 mm. Smaller pixel spacing, if desired, particularly allows for increased spatial resolution of the resulting tactile effect.

[0043] At least some pixels are arranged, for example, in rows and / or columns, especially when the carrier is flat, in the same plane, and preferably in a regular grid.

[0044] As a variation, in particular, pixels can be arranged in a concentric distribution.

[0045] actuator

[0046] Each touch pixel may be equipped with multiple actuators extending on one side of the pixel, such as the side located on one side of the carrier and / or the opposite side.

[0047] One or more actuators associated with a touch pixel may each have an elongated shape, preferably an elongated shape in the width direction of the pixel when the pixel has a rectangular shape.

[0048] The actuator can be placed on either side of the middle plane of the touch pixel, preferably at the vibration node or antinode.

[0049] Actuators can each have an overall polygonal shape, particularly a rectangle or square, or a circular shape.

[0050] Each actuator can be piezoelectric, ferroelectric, electromagnetic, or thermal. In particular, each actuator can be a piezoelectric ceramic.

[0051] Related systems

[0052] The interface may include a detection system for detecting user contact on the touch surface, particularly a capacitive sensing structure, which may be integrated into the haptic structure where appropriate.

[0053] The interface may include a system that allows images to be at least partially overlaid on a touch surface. The interface may therefore include a screen, and preferably a screen incorporating tactile structures.

[0054] The interface may include at least one actuator that allows the interface to be selectively shaped into at least two different shapes. For example, this could be useful for changing the shape of the interface according to the tactile sensation to be reproduced, in order to, for example, improve the quality of the simulation.

[0055] Another subject of the present invention is a garment article equipped with a tactile interface according to the present invention and as defined above.

[0056] Another subject of the present invention is a mobile device equipped with an interface according to the present invention and as defined above.

[0057] Tactile stimulation

[0058] Another subject of the present invention is a method for generating at least one tactile stimulus that can be felt by a user touching an interface according to the present invention, comprising the following steps:

[0059] - The detection system detects the user's contact position on the flexible touch surface of the interface.

[0060] - The control circuit modulates the signal sent to the actuator according to the detected position so as to mechanically cause the pixel to vibrate and produce an effect that the user can feel on the touch surface.

[0061] By moving a user's finger across a touch surface, the vibration of pixels can produce tactilely perceptible changes in friction. This effect, also known as a embossed effect, can give the user the impression of touching a surface with embossing or various textures.

[0062] The vibration of pixels can even produce tactilely perceptible pulses when a user applies static contact to a touch surface. For example, this effect allows a user to get the impression of pressing a button.

[0063] Creating Touch Pixels

[0064] Another subject of the present invention is a method for manufacturing a touch pixel equipped with a piezoelectric actuator and usable in an interface as defined above, comprising the following steps:

[0065] - Preferably, at least a first layer of conductive material is deposited on the upper surface of a rigid carrier (preferably a carrier made of glass) by screen printing.

[0066] - Attach the piezoelectric actuator to the first layer thus formed in order to establish a first electrical connection with the actuator.

[0067] - Deposit an insulating layer on the pre-deposited layer.

[0068] - Thin the insulation layer to expose the upper surface of each piezoelectric actuator.

[0069] - A layer of conductive material is deposited on the exposed actuator to establish a second electrical connection with the actuator.

[0070] - Cut the carrier to obtain multiple touch pixels, each equipped with one or more piezoelectric actuators.

[0071] This method, in particular, allows for the simple fabrication of multiple touch pixels using the same carrier (e.g., a glass plate).

[0072] The touch pixels thus obtained can then be transferred to a flexible carrier to form a tactile interface.

[0073] Another aspect of the present invention is a method for manufacturing a tactile interface as defined above, comprising the following steps:

[0074] - Deposit a first layer made of a flexible material, preferably a polymer, on a manufacturing carrier.

[0075] - A touch pixel equipped with one or more actuators is attached to the layer thus deposited, the actuators being placed on the outer surface of the pixel.

[0076] - Preferably, each actuator is electrically connected to the control circuit through a mask and sputtering of conductive material.

[0077] -The touch pixels and actuators are covered with a flexible material (preferably a polymer film), and,

[0078] -In particular, by peeling, the resulting components are separated from the manufacturing carrier to expose the lower surface of the first layer.

[0079] The first layer can form the aforementioned cover layer, and the flexible material deposited on the pixel can form the aforementioned receiving layer. Attached Figure Description

[0080] The invention may be better understood by reading the following detailed description of non-limiting examples of implementing the invention and by viewing the accompanying drawings, in which:

[0081] Figure 1 An example of a flexible tactile interface according to the present invention is shown partially and schematically.

[0082] Figure 2 An example of a haptic structure comprising touch pixels arranged in a matrix array is shown partially and schematically.

[0083] Figure 3 The example shown is partially and schematically illustrated, demonstrating the integration of touch pixels into the interface.

[0084] Figure 4 Is with Figure 3 The view shown is similar to another example of the integration of touch pixels.

[0085] Figure 5 An example of a flexible haptic interface equipped with the relevant system is shown partially and schematically.

[0086] Figure 6 This is a schematic partial perspective view of an example of a touch pixel equipped with two actuators.

[0087] Figure 7 It shows the actuator and Figure 6 Touch pixel contact and Figure 6Lamb patterns generated on touch pixels,

[0088] Figure 8 It is shown Figure 6 A graph showing how the resonant frequency of a pixel changes with its thickness.

[0089] Figure 9 This is a schematic partial perspective view showing the tactile structure of two touch pixels.

[0090] Figure 10 Through Figure 9 A schematic cross-sectional view of the thickness of the tactile structure.

[0091] Figure 11 This illustrates when the carrier is made of polyimide (PI). Figure 9 A diagram of the vibration of the tactile structure.

[0092] Figure 12A Partially and schematically illustrating the effect when the carrier is made of polyethylene naphthalate (PEN) Figure 9 The vibration of the tactile structure,

[0093] Figure 12B It is shown in Figure 12A A graph showing the vertical deformation amplitude of touch pixels in cross-section XII.

[0094] Figure 13A The diagram partially and schematically illustrates a tactile structure comprising a matrix array of touch pixels.

[0095] Figure 13B Partially and schematically shown to make Figure 13A The tactile structure has only a few touch pixels that can vibrate.

[0096] Figure 14 This is a block diagram illustrating an operational example of a tactile interface according to the present invention.

[0097] Figure 15A The possibility of generating button touch effects using the interface according to the invention is partially and schematically illustrated.

[0098] Figure 15B The possibility of producing an embossed touch effect using the interface according to the invention is partially and schematically illustrated.

[0099] Figure 15C The possibility of generating a textured touch effect using the interface according to the invention is partially and schematically illustrated.

[0100] Figure 16 , Figure 17 and Figure 18The following is a partial and schematic illustration of the sequential steps of an example method for manufacturing a touch pixel having its actuator.

[0101] Figure 19 , Figure 20 , Figure 21 and Figure 22 The sequential steps of an example method for manufacturing tactile structures are shown partially and schematically.

[0102] Figure 23A An example of a garment article equipped with a flexible tactile interface according to the present invention is shown.

[0103] Figure 23B An example of a mobile device equipped with a flexible haptic interface according to the present invention is shown, and

[0104] Figure 24 This demonstrates the possibility of modifying the shape of an interface using actuators. Detailed Implementation

[0105] Figure 1 An example of a flexible tactile interface 1 according to the present invention is shown. Interface 1 includes a tactile structure 2 defining a touch surface S. The tactile structure 2 includes touch pixels 3 carried by a flexible carrier 4. The touch pixels 3, referred to as pixels similar to optically active pixels of a screen, are rigid and placed on the carrier 4 such that the tactile structure 2 maintains overall flexibility in at least one direction, preferably in each direction.

[0106] The touch pixel 3 is equipped with one or more actuators 5, preferably piezoelectric actuators, which are connected to the control circuit 6 via an electrical connection 50. The control circuit 6 is configured to modulate the signal sent to the actuator 5 to mechanically induce its vibration and generate a tactile sensation on the touch surface S.

[0107] The tactile structure 2 can be any shape and can have various sizes. For example, depending on the application, its size is approximately one centimeter, one decimeter, or one meter.

[0108] The touch pixel 3 can be of various shapes, such as rectangle, square, circle, etc. The maximum size of the touch pixel 3 is, for example, between several hundred micrometers and several centimeters in side length, and preferably between 2 millimeters and 1 centimeter in side length.

[0109] The touch pixel 3 is made of glass, especially borosilicate glass, or silicon.

[0110] Touch pixels 3 can be distributed on carrier 4 in various configurations.

[0111] For example, in Figure 2 The image shows the same touch pixels 3 arranged in a regular array in rows and columns on the carrier 4.

[0112] In other embodiments (not shown), the interface 1 includes touch pixels of different shapes and / or sizes, or even touch pixels 3 that are concentrically distributed or staggered.

[0113] In particular, the size of the touch pixels can be adjusted to produce tactile effects that simulate larger or smaller patterns on the touch surface.

[0114] The spacing between touch pixels can also be adjusted to produce a haptic effect with higher or lower spatial resolution. The distance d between two touch pixels is preferably between tens of micrometers and a few millimeters, especially between 1 millimeter and 2 millimeters.

[0115] The carrier 4 carries the touch pixel 3 and participates in the cohesion of the tactile structure 2.

[0116] The carrier 4 can be single-layered or multi-layered. The carrier 4 is preferably made of a polymer, such as polyethylene naphthalate (PEN), polyimide (PI), or even polycarbonate (PC). The carrier 4 may also comprise one or more thin layers of metal oxide, silicon, or other metals. The thickness of the carrier depends on the properties of the material to maintain the required flexibility.

[0117] Touch pixel 3 can be integrated into haptic structure 2 in a variety of ways.

[0118] exist Figure 3 In the example shown, the carrier includes a carrier film 41 that can be used as a protective layer and a layer 40 for compensating for the thickness of pixel 3.

[0119] Pixel 3 is carried by film 41 and its entire thickness is embedded in compensation layer 40, which defines flexible segments 400 between pixels, also known as "hinges".

[0120] The outer surface 3a of the touch pixel 3 appears on the touch surface S. As shown, the compensation layer 40 may have an outer surface 40a flush with the surface 3a of the touch pixel to form a smooth surface therewith, which is substantially planar when the tactile structure 2 is flat. The compensation layer 40 may have substantially the same thickness as the touch pixel 3.

[0121] When a user places their finger on the touch surface S, they can directly touch the surface 3a of the touch pixel 3 of the interface.

[0122] As a variation, a thin protective layer (not shown) can be used to cover the touch pixel 3 and the compensation layer 40. This increases the uniformity of the touch surface and prevents the user from experiencing undesirable texture effects due to the difference between the material of the pixel and the material of the compensation layer 40.

[0123] exist Figure 3In the example shown, the actuator 5 is preferably located on the surface 3b of the touch pixel 3, which is located on one side of the carrier film 41, as shown. The touch pixel 3 equipped with the actuator 5 is fixed to the carrier 4, for example, by an insulating adhesive 55.

[0124] exist Figure 4 In the variant shown, the carrier 4 includes a layer 42 for receiving the pixel 3 and a cover layer 43.

[0125] The receiving layer 42 forms a basin-shaped housing 420, each housing 420 accommodating one touch pixel 3. A cover layer 43, such as a flexible polymer sheet, continuously covers the receiving layer 42 and the touch pixel 3, thereby enclosing the housing 420 from above.

[0126] Covering layer 43 is also used, for example, as a protective sheet to protect touch pixel 3.

[0127] In the example discussed, the free surface 43a of the cover layer 43 defines the touch surface S. The cover layer 43 is thin enough that the vibration effect of the touch pixel 3 can propagate to the touch surface S. The cover layer 43 has, for example, a thickness between a few micrometers and tens of micrometers.

[0128] In this variant, the actuator 5 may be invisibly located on the lower surface of the touch pixel 3, i.e., between the touch pixel 3 and the bottom of the housing 420 of the receiving layer 42, and / or on the upper surface of the touch pixel 3, i.e., between the touch pixel 3 and the cover layer 43. When some actuators 5 are present on opposite sides of the touch pixel 3, their excitation is preferably controlled to utilize the constructive vibrational interference between them.

[0129] exist Figure 5 In the example shown, the interface includes a detection system 7, such as a known prior art capacitive system, which allows the detection of at least one contact point between a user's finger and the surface S.

[0130] Detection system in Figure 5 The component is schematically shown in the form of a component covering the touch pixel 3 and the carrier 4, but it can form part of the carrier 4 or be integrated into the touch pixel.

[0131] Interface 1 may also include one or more related devices that allow for improvements to the user experience, especially making it a multi-sensory experience.

[0132] Interface 1 may therefore include a flexible screen (not shown) that allows images to be overlaid on the touch surface S, and, for example, gives the user the impression of virtually touching something he can see on the screen. Interface 1 may also include one or more speakers (not shown) to enhance audio effects.

[0133] Actuators 5 can have various shapes and sizes. The number, arrangement, and size of actuators 5 on touch pixels 3 depend on the desired effect.

[0134] Figure 6 An example of touch pixel 3 is shown, which takes the form of a rectangular plate with a width W of approximately 1 cm and a length L of approximately 1.5 cm. In the example discussed, the thickness e of pixel 3 is 500 micrometers.

[0135] Pixel 3 carries two strip actuators 5, each strip actuator having a width of approximately 2000 micrometers, and each strip actuator is positioned at a distance m of 2250 micrometers from the lateral edge of the pixel.

[0136] The actuator 5 has a thickness of, for example, 2 micrometers, and has an active layer based on, for example, aluminum nitride (AlN), lead zirconate titanate (PZT), or any other suitable ferroelectric or piezoelectric material.

[0137] According to the method described in the paper “Low voltage actuated plate for haptic applications with PZT thin-film” by Caste, F. et al. (Proceedings of Transducers, 2013), for example, the size and position of the two actuators 5 are selected to generate a Lamb oscillation mode in the touch pixel at a frequency of approximately 61 kHz.

[0138] like Figure 7 As shown, actuators 5 can be located at the antinodes of the vibration modes they generate. However, other actuation configurations, such as actuators positioned at vibration nodes, are also possible. For example, Figure 7 The implementation allows for frictional variations on the touch pixel 3 that can be tactilely perceived by the user moving their finger across the touch surface.

[0139] It is possible to obtain a tactile effect similar to that described above, which is achieved using touch pixels with different thicknesses.

[0140] In particular, multiple vibration modes can be generated at frequencies that depend on the thickness of the touch pixel 3. A lamb mode as described above, or a first vibration mode along the length L dimension of the pixel, or even a first vibration mode along the width W dimension of the pixel, can be generated in the touch pixel 3.

[0141] Using the method described in Poncet et al.'s paper "Design and realization of electroactive polymeractuators for transparent and flexible haptic feedback interfaces" (EuroSime, 2016), various vibration modes can be obtained by adjusting the piezoelectric actuator.

[0142] Figure 8 The graph shows examples of resonant frequencies corresponding to the three vibration modes mentioned above, which, along with others, include... Figure 6 The two strip actuators shown have a planar dimension of 1 x 1.5 cm. 2 The pixel thickness variation of the touch pixels.

[0143] As can be seen from the figure, if one wishes to use the Lamb pattern (represented by the circles in the chart) to produce the desired haptic effect, it is advantageous to choose a touch pixel thickness between 200 and 700 micrometers to keep the frequency inaudible to the human ear, i.e., above about 20 kHz, and below 100 kHz, in order to keep the control of electronic devices relatively simple.

[0144] Similarly, if you want to utilize the first vibration mode in the dimension of pixel length L (represented by the triangle in the diagram), you would choose a touch pixel thickness greater than 900 micrometers.

[0145] Finally, if you want to utilize the first vibration mode in the dimension of pixel width W (represented by the squares in the chart), you would choose a touch pixel thickness between 500 and 900 micrometers.

[0146] The thickness of pixel 3 is also limited by the stiffness required to perceive the touch effect. Specifically, low stiffness of touch pixel 3, especially low stiffness caused by small thickness, can reduce the force exerted by touch pixel 3 on the user and thus reduce the perceived effect. In contrast, greater thickness of touch pixel 3 reduces the amplitude of pixel vibration, which may therefore weaken the perceived tactile effect.

[0147] A thickness between 50 micrometers and a few millimeters, preferably between 200 micrometers and 700 micrometers, may be a good compromise.

[0148] In one variation, actuators 5 are arranged in a matrix array on touch pixels 3. In one example, they are approximately 5x5mm in size, spaced regularly at 2mm intervals. 2The square actuators 5 are distributed on the pixel 3 in this manner. In another example, the touch pixel 3 is equipped with a single actuator 6, which is placed, for example, at the center of one of its main surfaces.

[0149] The stiffness of the carrier 4 that supports the touch pixel 3, relative to the stiffness of the touch pixel 3, also affects the quality of the resulting tactile effect.

[0150] The vibration simulation results of tactile structure 2 are described below, for example... Figure 9 As shown, the tactile structure 2 includes two components that support... Figure 6 Similar to the carrier 4 of touch pixel 3. These results were obtained using the commercially available software package COVENTOR, but any other software package, especially those that allow finite element analysis, is available.

[0151] In the examples discussed and as Figure 10 As shown, the touch pixel 3 is embedded in the carrier 4 and has an outer surface 3a appearing on the touch surface S. The structure of the carrier 4 is as shown in the reference. Figure 3 As described.

[0152] Touch pixels 3 are, for example, borosilicate glass sheets approximately 500 micrometers thick. Their Young's modulus is approximately 65 GPa to 70 GPa.

[0153] The carrier has a length L of 3.5 cm. S 2.5cm width W S The total thickness h equals 525 micrometers. E +h P The thickness h of the compensation layer 40 E The thickness h of the carrier film 41 is 500 micrometers. P It is 25 micrometers.

[0154] Figure 11 The simulation results show the vibration amplitudes of this tactile structure in the X, Y, and Z directions at frequencies between 60 kHz and 70 kHz when the carrier 4, used as a comparative example, is made of PI, where the Young's modulus of the PI material is approximately 7.5 GPa. The desired vibration modes were not obtained under these conditions, and a favorable tactile effect was not produced. The carrier 4, made of PI, is too rigid, applying mechanical boundary conditions to the periphery of the touch pixels and restricting their vibration.

[0155] Conversely, when carrier 4 is made of PEN material with a Young's modulus of approximately 0.75 GPa, a natural Lamb pattern can be generated in tactile structure 2, such as... Figure 12A As shown.

[0156] like Figure 12BAs shown, when the corresponding actuator 5 is subjected to an AC voltage of + / -30V, the corresponding deformation amplitude A of the touch pixel 3 can reach + / -2 micrometers, which allows for a noticeable tactile effect.

[0157] Therefore, a Young's modulus ratio of approximately 65 GPa / 7.5 GPa, or approximately 8, cannot produce the desired tactile effect under simulated conditions. In contrast, a ratio of approximately 86 (corresponding to 65 GPa / 0.75 GPa) allows for the desired effect.

[0158] Of course, other thicknesses h P and h E This is conceivable. For example, for polymers such as PEN, PI, or PC, a thickness between 100 micrometers and several centimeters, preferably several millimeters, allows the carrier to provide mechanical strength while maintaining flexibility.

[0159] Thickness h P Preferably small enough, especially relative to h E Small enough not to disrupt the electromechanical behavior of touch pixel 3. Thickness h P For example, the range is between tens of nanometers and hundreds of micrometers, and preferably between 25 micrometers and 90 micrometers.

[0160] As mentioned above, the carrier 4 can be multilayered or single-layered. In the case of a multilayered carrier, the Young's modulus E of the carrier... T and total thickness h T The following approximations may be used to obtain the value, which is known in the prior art:

[0161] h T =∑h i

[0162]

[0163] h i and E i These are the thickness and Young's modulus of the i-th layer, respectively.

[0164] One or more actuators for each touch pixel 3 of interface 1 can be addressed independently by control circuitry 6, which allows for the generation of tactile effects that are relatively positioned on touch surface S.

[0165] For example, by activating only a matrix array of 3x3 touch pixels (i.e., such as...). Figure 13A The central touch pixel 300 of the matrix array shown can, for example, obtain perceptible deformation of the touch surface S only at the center of the touch surface S, such as... Figure 13B As shown.

[0166] The tactile interface 1 according to the present invention can be based on Figure 14Follow the steps shown.

[0167] In step 81, the interface is in standby mode and the touch pixel 3 is stationary when no user touches the touch surface S.

[0168] In step 82, the detection system 7 detects at least one contact point between the user and the surface S, and the control circuit 6 determines the location where one or more tactile effects must be produced.

[0169] In step 83, the control circuit 6 sends appropriate control signals to actuate at least some of the actuators 5, thereby producing the desired tactile effect.

[0170] In step 84, the actuators 5 in question contract or elongate by the inverse piezoelectric effect, having an actuation amplitude corresponding to the received signal, thereby generating vibrations of the rigid pixels 3 in contact with them by a singlet effect.

[0171] In step 85, the vibration of one or more touch pixels caused by the actuator is perceived by the user's touch on the surface S.

[0172] In step 86, if it is desired, for example, to save energy, the user disconnects from the touch surface S and the interface can return to standby mode.

[0173] For example, the tactile perception generated in step 85 comes from the vibration of the touch pixels, which may give the user the impression of touching a vibrating surface or a surface with an embossed design.

[0174] Relatively complex effects can be produced by actuating more or fewer touch pixels. Some of these effects will be described below and in... Figure 15A , Figure 15B and Figure 15C The explanation is as follows.

[0175] In the following example, a matrix array 10 of identical touch pixels 3 will be considered, which have a circular shape and are uniformly staggered on the matrix array 10. Each touch pixel includes an actuator 5 placed at its center.

[0176] exist Figure 15A In the example shown, a group of touch pixels 30 belonging to matrix array 10 is actuated by control circuit 6 to send a pulse of tactile perception 60 corresponding to a "key click effect" to user U who is applying static contact to the surface, that is, to give the user the impression of pressing a keyboard key.

[0177] In another example, such as Figure 15BAs shown, multiple sets of actuators 31 and 32 are actuated simultaneously or alternately to produce tactile sensations 61 and 62 with a pseudo-embossed effect, that is, to give a user who is moving his finger to contact the interface a feeling of brushing over an embossed surface, such as the peaks of a map displayed on the screen.

[0178] In another example, such as Figure 15C As shown, multiple sets of touch pixels 33 and 34 are activated simultaneously or alternately to produce tactile perceptions 63 and 64 with a textured effect, that is, to give the user, who is moving his finger to contact the interface, the impression of touching the smooth surface 64 of the watch face or the rougher surface 63 of the watch strap.

[0179] By moving his finger, the user can perceive changes in friction, also known as the squeezing film effect. This is because the touch pixel 3 generates, for example, an ultrasonic pattern or an evanescent wave when it is excited by the actuator 5.

[0180] In the example just described, a given group of touch pixels 3 can be activated with the same vibration mode for all touch pixels in that group or with a vibration mode specific to each touch pixel, depending on the desired effect.

[0181] The touch pixel 3, equipped with a piezoelectric actuator 5, can follow Figures 16 to 18 The steps shown and described below are used to make it.

[0182] First, for example by screen printing, a first layer 24 of conductive material, such as gold, is deposited on the upper surface of a rigid plate 22, particularly a plate made of glass.

[0183] Layer 24 is discontinuous: for example, it comprises multiple separate sections 24a and 24b that form the power supply track for the actuator 5, which will contact the touch pixel 3.

[0184] The thickness of plate 22 is, for example, 500 micrometers. The thickness of layer 24 is, for example, 300 nm.

[0185] Next, a piezoelectric actuator 5 is transferred, comprising, for example, a lower electrode 52, a ferroelectric or piezoelectric layer 54, and an upper electrode 56. As a variation, the actuator 5 comprises only layer 54.

[0186] Layer 54, located between the two electrodes, is made of, for example, lead zirconate titanate (PZT). It can also be made of aluminum nitride (AlN), zinc oxide (ZnO), or any other suitable ferroelectric or piezoelectric material. Layer 54 can also be thinned and adjusted to the desired thickness.

[0187] As described in patent FR3082997, commercially available piezoelectric ceramics can be used, or the actuator 5 can be formed by depositing thin layers on plate 22 and patterning them.

[0188] like Figure 16 As shown, the lower electrode 52 of the piezoelectric actuator 5 can be connected to the track 24 via a conductive adhesive layer 51, such as silver paste, having a thickness of approximately 40 μm. The deformation of the piezoelectric layer 54 under the influence of the potential difference applied between the electrodes is transmitted to the plate 22 through a singlet effect in layer 51.

[0189] Next, each actuator 5 is covered with an electrical insulating layer 58, for example, made of polymer, to hold the actuator 5 in place and insulate the electrodes 52 and 56.

[0190] like Figure 17 As shown, only a portion of the power supply track 24a is not covered.

[0191] Next, the insulating layer 58 is thinned from above to expose the electrode 56, thereby connecting the upper electrode 56 to the power supply track 24a by depositing a conductive material layer 26 through inkjet printing or other suitable methods. Figure 18 As shown.

[0192] As a variation, the insulating layer 58 and the piezoelectric layer 54 can be thinned to the desired thickness, and then a conductive material layer 26 forming the upper electrode and the connection to the track 24a can be deposited. Where appropriate, layer 26 is obtained using a template and gold sputtering, and its thickness is, for example, 300 nm.

[0193] The board 22 can then be cut to the required size and equipped with the desired number of touch pixels 3 of actuators 5.

[0194] To form tactile structure 2, for example by following the references below Figures 19 to 22 The fabrication steps described herein allow the obtained touch pixels 3 to be transferred and fixed onto the flexible substrate 4. Specifically, the above-described reference can be obtained by following the steps described above. Figure 4 The described tactile structure.

[0195] First, the touch pixel 3 is placed at the desired position on the manufacturing carrier 100 (e.g., a silicone board), on which a flexible layer 42, such as a flexible layer formed of SINR polymer, has been pre-formed by lamination, which is intended to form, for example, the aforementioned cover layer.

[0196] Touch pixel 3 is held in place, for example, by a rigid adhesive (e.g., epoxy adhesive) layer 44 with a thickness of, for example, 40 micrometers. Figure 19 As shown.

[0197] Subsequently, a conductive material layer 46, such as a 300 nm thick gold layer obtained by masking and sputtering, is deposited to form an electrical connection between each actuator 5 and the control circuit 6, as shown below. Figure 20 As shown.

[0198] An insulating layer 45, such as polymer beads, may be pre-deposited around the touch pixel 3.

[0199] Next, for example by rolling or bonding, all touch pixels 3 and their actuators 5 are continuously covered with a layer 42, especially a soft polymer film, to form flexible bridges between the touch pixels 3, such as... Figure 21 As shown. Layer 42 is intended to form the aforementioned receiving layer.

[0200] As a variant, touch pixel 3 can be coated with a soft polymer.

[0201] Finally, the manufacturing carrier is peeled off to expose the cover layer 43, and the uncovered surface defines the touch surface S of the flexible tactile interface. As a variation, the touch surface can also be defined by the upper surface 2a of the tactile structure.

[0202] like Figure 23A As shown, the interface 1 according to the present invention can be integrated into clothing products, such as gloves.

[0203] As a variant, this interface can be integrated into mobile devices, such as flexible phones, for example. Figure 23B As shown.

[0204] In other examples, the haptic structure 2 can also change shape according to the desired haptic effect, and the interface 1 may become a reconfigurable tangible object due to its flexibility, such as... Figure 24 As shown in the figure, the interface can be mechanically connected to one or more actuators 11, which allow the actuators 11 to deform to give them a predetermined shape, corresponding to the shape of the object it is trying to simulate in a tactile manner.

Claims

1. A flexible tactile interface (1), comprising: Tactile structure (2), the tactile structure (2) defining a touchable surface (S) that can be touched by a user, the tactile structure comprising: Multiple rigid touch pixels (3) supported by a flexible carrier (4), the pixels (3) being made of glass or silicon, and the carrier (4) being formed of a polymer material. At least one actuator (5), each pixel (3) is in contact with the at least one actuator and the at least one actuator is arranged to transmit a mechanical excitation to the pixel (3) that results in an effect that can be perceived by the user through touch.

2. The interface according to claim 1, comprising a control circuit (6) configured to modulate a signal sent to the actuator to mechanically cause vibration of the pixel (3) and generate a tactile sensation on the touch surface.

3. The interface according to claim 1, wherein, Some pixels (3) or all pixels have a substantially constant thickness.

4. The interface according to claim 1, wherein, At least some pixels (3) have an outer surface (3a) that appears on the touch surface (S).

5. The interface according to claim 1, wherein, The carrier (4) includes a carrier layer (41) and a compensation layer (40) for compensating for the thickness of the pixels (3), all of which are located on the same side of the carrier layer (41). The compensation layer (40) includes flexible segments (400) extending between the pixels (3), and the compensation layer (40) has a substantially constant thickness (h). E ).

6. The interface according to claim 5, wherein, The pixel (3) has an outer surface (3a) that is flush with the outer surface (40a) of the compensation layer (40), and the outer surface of the pixel and the outer surface of the compensation layer define the touch surface (S).

7. The interface according to claim 1, wherein, The carrier (4) forms a shell (420), and the pixel (3) is located at least partially in the shell (420), the pixel being continuously covered by a flexible sheet (43) defining the touch surface.

8. The interface according to claim 1, wherein, The spacing (d) between two adjacent pixels (3) is between 10 micrometers and 5 millimeters.

9. The interface according to claim 1, wherein, At least some pixels (3) are arranged in rows and / or columns.

10. The interface according to claim 1, wherein, Each pixel (3) is equipped with a plurality of actuators (5) extending on at least one face (3b) of the pixel.

11. The interface according to claim 10, wherein, The actuator (5) is placed on either side of the middle plane of the pixel (3), the location including a vibration node or antinode.

12. The interface of claim 1, comprising a detection system (7) for detecting contact of the user on the touch surface, the detection system comprising a capacitive detection structure integrated into the tactile structure.

13. The interface of claim 1, comprising a system that allows an image to be at least partially superimposed on the touch surface, the system comprising a screen including the tactile structure.

14. The interface according to claim 1, comprising at least one actuator (11) that allows the interface to be selectively shaped into at least two different shapes.

15. A method for generating a tactile sensation perceptible to a user touching an interface as described in claim 1, comprising the steps of: The detection system detects the user's contact position on the flexible touch surface (S) of the interface. The control circuit (6) modulates the signal sent to the actuator (5) according to the detected position so as to mechanically cause the pixel (3) to vibrate and produce the effect that the user can perceive on the touch surface.

16. The method according to claim 15, wherein, The vibration of the pixel (3) generates a tactilely perceptible change in friction as the user moves his finger on the touch surface (S).

17. The method according to claim 15, wherein, The vibration of the pixel generates a pulse that can be tactilely perceived by the user applying static contact on the touch surface (S).

18. A method for manufacturing a touch pixel (3) equipped with at least one actuator of the interface as claimed in claim 1, said actuator being a piezoelectric actuator (5), the method comprising the steps of: A first layer of conductive material is deposited on the upper surface of a rigid carrier made of glass (24). The piezoelectric actuator (5) is fixed to the first layer (24) to establish a first electrical connection with the actuator. An insulating layer (58) is deposited on the first layer. Thin the insulating layer (58) to expose the upper surface of each piezoelectric actuator (5). A conductive material layer (59) is deposited on the actuator thus exposed in order to establish a second electrical connection with the actuator. The carrier is cut to obtain multiple touch pixels (3) equipped with one or more piezoelectric actuators.

19. A method for manufacturing the interface as claimed in claim 2, comprising the following steps: A first layer (43) made of a first flexible material, comprising a polymer, is deposited on a manufacturing carrier (100). A rigid pixel (3) equipped with one or more actuators (5) is fixed to the first layer, the actuators being placed on the lower surface (3a) or the upper surface of the pixel (3). Each actuator (5) is electrically connected to the control circuit (6). The pixel and the actuator are covered with a second flexible material (42), the second flexible material (42) comprising a polymer film, and The resulting components are separated from the manufacturing carrier (100) to expose the lower surface of the first layer.

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