HAPTIC READER IMPLEMENTING THE BRAILLE-PERKINS METHOD

Description

TECHNICAL FIELD AND STATE OF THE PRIOR ART

[0001] The present invention relates to a haptic reading device implementing the Braille-Perkins method, more particularly to a haptic reading device implementing the Braille-Perkins method using the inverse filtering method.

[0002] Visually impaired people can read text that has been translated into the Braille alphabet, in which each character is represented in a matrix of six dots by two columns, each character being formed by one to six raised dots. Accessing digital content using the Braille alphabet requires the use of a Braille display, which is a heavy, bulky, fragile, and expensive object. This display cannot be carried around like a smartphone.

[0003] There is a typewriter, called a Perkins machine, which allows you to write a text in Braille. It is a typewriter with six keys, each key corresponding to a dot in a Braille character. The user places the index, middle, and ring fingers of each hand on a key. The index finger of the left hand corresponds to dot 1, the middle finger of the left hand corresponds to dot 2, the ring finger of the left hand corresponds to dot 3, the index finger of the right hand corresponds to dot 4, the middle finger of the right hand corresponds to dot 5, and the ring finger of the right hand corresponds to dot 6.

[0004] This writing method will be called the Braille-Perkins method. This method is applied to reading, which consists of using the index, middle and ring fingers of each hand.

[0005] There are touch-sensitive surface devices that send stimulations to the index, middle and ring fingers of each hand, but there is a problem with localizing the vibrations. Activating an actuator to stimulate one of the fingers can cause the neighboring areas of that finger to vibrate and also activate one or more of the other fingers, thus transmitting false information to the reader.

[0006] The paper Nicolau, HM "Holibraille: Multipoint vibrotactile feedback on mobile devices". Proceedings of the 12th Web for All Conference, 1-4 May, 18-20, 2015 describes a device comprising a rectangular housing to which six actuators are attached via springs. Three actuators are arranged in a column along a first edge of the housing and three actuators are arranged in a column along a second edge of the housing parallel to the first edge. Each actuator represents a point in the Braille matrix. The user places his fingers in direct contact with the actuators. The use of springs to connect the actuators to the housing allows vibrations to be localized and prevents vibrations from being transmitted from an actuator to a finger other than the one in direct contact with the vibrating actuator. Character reading is then possible. This device is bulky and fragile; the actuators protrude from the housing.

[0007] Rantala, JR, "Methods for presenting braille characters on a mobile device with a touchscreen and tactile feedback," IEEE Transactions on Haptics, 28-39; Jan. 15, 2009, describes a mobile device for reading Braille characters by tactile feedback. The device has a screen under which a piezoelectric actuator is attached that vibrates the entire screen. The user detects the vibration directly with their finger or a stylus. Haptic feedback cannot be localized on the screen. A character can only be read point by point. EP 3 705 983 A1 (UNIVERSITÄT HEIDELBERG [DE]) September 9, 2020 (2020-09-09) describes a device for reading Braille characters by tactile feedback. The device does not limit the risks of misinterpretation of signals by the user. STATEMENT OF THE INVENTION

[0008] It is therefore an aim of the present invention to provide a haptic device implementing the Braille-Perkins method which is simple and comfortable to use and limits the risks of misinterpretation of the signals by the user.

[0009] The aim stated above is achieved by a haptic device comprising a plate provided with a surface with which the user's fingers will come into contact, actuators fixed to the plate, said actuators being capable of generating a vibration at the surface in distinct zones, means for controlling said actuators, comprising means for calculating the control signals implementing an inverse filtering operation, and sending control signals to the actuators. The control means are configured to vibrate between one and six zones of the surface to allow at least the haptic display of Braille characters by the Braille-Perkins method.

[0010] The use of inverse filtering to calculate actuator control signals makes it possible to compensate for the effects of wave propagation outside the area(s) on which the fingers are placed, thus preventing fingers from being stimulated incorrectly, which would distort the reading. In particular, the fingers intended to be stimulated may be close together, for example the index and middle fingers or the middle and ring fingers of a hand. Thanks to the invention, the vibrations emitted under the middle finger will not be felt by the index or ring fingers.

[0011] The stimulations reproducing each point of a Braille character can be simultaneous, successive or grouped by two or more.

[0012] Advantageously, a large number of actuators are used to optimally generate vibrations in all areas of the surface. This allows the user to freely position their fingers on the surface without this impairing the reading. Preferably, an interpolation method is used to calculate the responses in the areas between the actuators.

[0013] Preferably, a prior step of detecting the location of the fingers on the surface is implemented to identify where the index, middle and ring fingers of each hand are located.

[0014] Very advantageously, the haptic device is also suitable for text input. For this purpose, the device includes means for detecting the force exerted by each of the fingers. Very advantageously, the force detection means can measure the intensity of the force, so that the user can permanently leave their fingers on the surface and modulate the pressure of their fingers on it to enter text. In a preferred example, it is the actuators that form the force detection means.

[0015] The present invention can be integrated into portable devices such as mobile phones such as smartphones or touch tablets, but also into home automation devices, for example cooking hobs and other household appliances.

[0016] The subject of the present application is a haptic device for reading by the Braille-Perkins method comprising a plate provided with a surface with which at least the index, middle and ring fingers of each hand of the user are intended to come into contact, actuators fixed to the plate opposite said surface, said actuators being capable of generating a vibration at the surface in distinct zones, a unit for controlling said actuators, comprising means for calculating the control signals implementing an inverse filtering operation, and configured to send control signals to the actuators, the control unit being configured to vibrate n zones of the surface, n being an integer between 1 and 6, to stimulate the index, middle and ring fingers of each hand of the user and to reproduce by haptic stimulation the Braille characters by the Braille-Perkins method,each area corresponding to a point of a Braille character.,

[0017] In an exemplary embodiment, the control unit is configured to simultaneously vibrate the n zones.

[0018] In another exemplary embodiment, the control unit is configured to successively vibrate the n zones.

[0019] The device advantageously comprises means for detecting the presence of the index, middle and ring fingers of each hand of the user and in which the control unit is configured to locate the position of the index, middle and ring fingers of each hand of the user on the surface and record said positions.

[0020] For example, the detection means include means for measuring the pressure exerted by each finger on the surface.

[0021] The haptic reading device may include means for controlling the display of characters on the surface.

[0022] Another subject of the present application is a haptic device for displaying and inputting Braille characters using the Braille-Perkins method comprising a haptic reading device according to the invention, in which the control unit is also configured to translate a measurement of the pressure exerted for each finger into a point on a Braille character and to identify the Braille character.

[0023] Another subject of the present application is a method of operating a haptic device for reading digital content given by a user according to the invention, comprising: a) placing at least the index, middle and ring fingers of each hand of the user on the surface of the device, b) translating the digital content into Braille characters, c) for each Braille character, generating signals to the actuators so that they vibrate n areas of the surface, said areas being covered by the index, middle and ring fingers of each hand of the user.

[0024] The operating method advantageously comprises, between step a) and step b), a step of identifying the location of the index finger, middle finger and ring finger of each hand of the user on the surface and associating each of these fingers with said location.

[0025] Another subject of the present application is a method of operating a haptic device for displaying and inputting Braille characters using the Braille-Perkins method according to the invention, implementing the steps of the operating method according to the invention, and comprising: measuring the pressure exerted by the index, middle and ring fingers of each hand, comparing it to a threshold value, translating the measurements into a point on a Braille character and identifying the Braille character. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be better understood on the basis of the following description and the attached drawings in which: There figure 1 is a schematic representation of an exemplary haptic device according to the present invention. The figure 2 is a schematic representation of a side view of the haptic device of the figure 1 . There Figure 3Ais a transcription of the letter d in Braille. The Figure 3B represented the device of the figure 1 during the haptic display of the d according to a first mode of operation. The Figure 3C is a graphical representation of vibration amplitude versus time at zones Z1 to Z6 to haptically display the d in the first operating mode. The figure 4 is a graphical representation of the vibration amplitude versus time at zones Z1 to Z6 to haptically display the d in a second operating mode; and The Figure 5 is a graphical representation of vibration amplitude versus time at zones Z1 to Z6 to haptically display the d in a third operating mode. DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0027] On the figure 1, we can see a schematic representation of a top view of a haptic device according to the invention, comprising a plate 1, carrying on one of its faces the surface for interaction with the exterior, designated touch surface 2, a plurality of actuators A1, A2... An arranged under the plate 1, for example fixed on the surface of the plate 1 opposite the touch surface 2. The haptic device also comprises a control unit 6 for each of the actuators comprising means 8 for calculating the control signals.

[0028] The plate material is chosen so that it allows low frequency vibrations, typically below 1000 Hz, preferably between 150 Hz and 1000 Hz which is the tactile sensitivity frequency band, to propagate over a few centimeters (cm). The material can be a flexible or rigid material, for example glass.

[0029] The actuators are such that they are capable, when activated, of exerting a force on the plate in an out-of-plane direction, i.e. orthogonal to the plane of the plate. The plane of the plate is the plane extending parallel to its largest surface. On the figure 2 , we can see an example of a side view of the interface of the figure 1 . The actuators are capable of exerting an upward and / or downward force in the representation of the figure 2 .

[0030] The actuators can be in direct contact with the plate.

[0031] Actuators are, for example, piezoelectric actuators. This type of actuator is commonly used in touch interfaces. A piezoelectric actuator comprises a piezoelectric material in the form of a plate, for example PZT (Lead Zirconate Titanium) or AlN (Aluminum Nitride), and electrodes on either side of the plate and in contact with it, to apply a current to it causing the deformation of the piezoelectric material.

[0032] Thanks to the invention, it is also possible to give a controlled profile to the surface. Indeed, a permanent deformation of the surface can be seen as a vibration of zero frequency. We can therefore apply the inverse filter method. By exerting a localized force on a plate, the entire surface is deformed. By applying the inverse filter method, we can cancel this deformation at the desired points.

[0033] Electromagnetic actuators are possible. They are suitable for low-frequency operation. Such actuators are, for example, described in the document Benali-Khoudja et al. - 2007 - VITAL An electromagnetic integrated tactile display ». For example, actuators each have a fixed coil and a magnet glued under the touch surface. The current signal sent to the coils is calculated by inverse filtering.

[0034] The user is intended to interact with the touch surface 2, in particular by placing the index finger, middle finger and ring finger of each hand on the touch surface and feeling vibrations at the level of one or more of these fingers.

[0035] The fingers can be arranged vertically or not in line with the actuators A1 to An.

[0036] For example, the actuators have a disc shape with a diameter Ø between 20 mm and 35 mm. Alternatively, they can have the shape of a hexagon which is close to the shape of a disc, ensuring maximum paving under the touch surface.

[0037] The device preferably implements a large number of actuators under the entire interaction surface, which improves the near-field control of the device. The potential stimulation zones are located in the near field of the actuators, i.e. the potential stimulation zones are located at a distance less than or equal to the dimension of the actuators in the plane or to the wavelength of the control signals sent to the actuators, whichever is greater.

[0038] This near-field configuration allows efficient control by reducing the power of the emitted signals to obtain given displacements, especially when the control points are less than one wavelength apart.

[0039] The actuators can be fixed, for example by gluing directly onto the face of the plate 1 opposite the touch surface 2. The actuators are independent. Alternatively, the actuators comprise in common a layer of piezoelectric material, a common electrode between the piezoelectric layer and the plate and electrodes on the opposite face of the piezoelectric layer so as to produce individual actuators.

[0040] The calculation means 8 implement an inverse filtering operation to determine the control signals. The calculation means also implement a vibration synthesis algorithm determining the desired signal in a zone, depending on the desired stimulation in this zone, and taking into account for example the pressing force on this zone. This type of algorithm is well known to those skilled in the art and will not be described in detail.

[0041] The inverse filtering operation is for example described in the article « Optimal focusing by spatio-temporal inverse filter. I. Basic principles » M. Tanter et al., The Journal of the Acoustical Society of America 110, 37 (2001 )applied to image processing in medical imaging. An example of implementing the inverse filtering operation to determine actuator control signals of a surface device is described in document WO2021922762 and in the article Lucie Pantera and Charles Hudin, “Multitouch Vobrotactile Feedback on a Tactile Screen by the Inverse Filter Technique: Vibration Amplitude and Spatial Resolution” in Transactions on Haptics - Special issue on surface haptics, pp 1-11 2020 .

[0042] The response R of a linear system to an excitation E is given by the relation R=HE, with H the transfer function of the system. In the application to a touch interface, we observe the displacement U i of the plate measured at a point i, for example at the center of an actuator, in response to a signal S j sent to an actuator j. So we have: U i ω = H ij ω S j ω

[0043] With H ij ( ω) the transfer function between the signal sent to the actuator j and the displacement recorded at the point i. If N actuators emit simultaneously, the displacement obtained is the sum of the contributions of these N actuators, i.e.: U i ω = ∑ j = 1 N H ij ω S j ω

[0044] In matrix form in the case of M control points i we write: U 1 U 2 ⋮ U M ω = H 11 H 12 H 21 H 22 ⋯ H 1 N H 2 N ⋮ ⋱ ⋮ H M 1 H M 2 ⋯ H MN ω ⋅ S 1 S 2 ⋮ S N ω

[0045] Or U ω = ℍ ω . S ω

[0046] The move yes at the checkpoint i therefore depends on all the signals sent to all the actuators. All the actuators therefore participate in the movement at each control point i. The movement yes is therefore not proportional to the signal if which is applied to it, but depends, via the terms Hi ij, signals sent to other actuators which produce waves propagating throughout the plate.

[0047] Inverse filtering involves inverting this relationship by calculating the signal to be applied to all the actuators to obtain the desired displacement. Noting V ω = V 1 V 2 ⋮ V M ω the desired displacement, in the frequency domain, at all positions, we calculate the signal S ω = S 1 S 2 ⋮ S N ω to send to each of the actuators by the relation: S ω = ℍ ω − 1 . V ω

[0048] We finally get a displacement U ω given by: U ω = ℍ ω . S ω = ℍ ω . ℍ ω − 1 . V ω = V ω

[0049] We thus obtain a displacement conforming to that expected: U ω = V ω .

[0050] By inverting the matrix, all the effects are compensated before generating the control signals to obtain the desired displacement despite distortions, reverberations and wave propagation. The matrix is determined during a calibration phase during which the vibrations in the areas above each of the actuators caused by the actuation of the actuators are measured, as well as the propagation, reverberation and attenuation of the waves in these areas.

[0051] This filter is temporal insofar as it operates a transformation on the amplitude and phase at all frequencies, and spatial since it takes into account the signals emitted by all the actuators.

[0052] By means of the inverse filtering operation, control signals are sent to all the actuators and are such that, for the areas for which no stimulation is desired, the actuators generate vibrations aimed at cancelling those resulting from propagation of the activation of the actuator under the area(s) where stimulation is desired.

[0053] The calculation of the actuator control signal under the area where stimulation is to be generated takes into account both the desired displacement and the effect of the propagation and reflection of the vibrations produced by the other actuators. According to the invention, each actuator is therefore controlled taking into account the external environment.

[0054] We can then obtain, in each area of the surface, a displacement which can be zero, corrected for distortion and reverberation effects, and independent of the displacements in the center of the other areas.

[0055] According to one mode of operation of the invention, the calculation means are configured to simultaneously generate vibrations in at most six locations intended to stimulate the index, middle and ring fingers of each hand, these locations not being able to be defined before placing the fingers on the touch surface.

[0056] Applying the inverse filtering method to generate control signals to the actuators makes it possible to localize the generated vibrations very precisely and thus avoid, for example, stimulating both the middle and ring fingers of the left hand when only the middle finger should be excited. All actuators receive an activation signal to at least partially compensate for distortion, reverberation and wave propagation outside the areas covered by the index, middle and ring fingers of both hands.

[0057] Furthermore, advantageously, in order to be able to generate vibrations at any point of the surface and thus make the placement of the fingers on the touch surface even freer, an interpolation step is carried out allowing the impulse response to be theoretically calculated at each point of the surface. As indicated above, a surface calibration step is carried out where the impulse responses of the surface are recorded in a matrix ĥ cq ( t ) where c = 1...C, with C the number of calibration points chosen for calibration and q the number of actuators. From this matrix ĥ cq ( t ) and abscissa coordinates xf and in ordinate yf with the finger / fingers on the screen we can calculate the matrix h fq ( t ) corresponding precisely to the location of the finger(s) which allows for much faster and more precise calculations. To obtain the matrix h fq (t ), a Fourier interpolation as below is performed: h fq t = ∑ c = 1 C h ^ cq t . sinc π x f − x c dx . sinc π y f − y c dy Or : sinc(x) = sin( x ) / x : The cardinal sine function, xf : The coordinates of the finger(s) on the x axis, yf : The coordinates of the finger(s) on the y axis, xc : The coordinates of the calibration points on the x axis, including : The coordinates of the calibration points on the y axis, ĥ cq : The impulse response measured at the calibration points.

[0058] The haptic device also comprises means 10 for detecting the presence of fingers on the touch surface. For example, these may be capacitive, resistive or infrared means; these means are well known to those skilled in the art and will not be described in detail in the present application. The device comprises, for example, a capacitive screen. A local variation in the capacitance corresponds to pressure exerted by a finger and therefore to the presence of a finger.

[0059] Advantageously, the control unit 6 is configured to launch at the start of use of the haptic device a step of locating the fingers on the touch-sensitive surface 2, more particularly the location of the index, middle and ring fingers of each hand and to associate with them the zones Z1 to Z6 of the touch-sensitive surface 2. Thus the positions of the six fingers will be known and the vibrations to reproduce the letters according to the Braille-Perkins method can be generated in the zones detected and associated with the index, middle and ring fingers of each hand. The implementation of such locating means allows the user to be able to hold the haptic device without an orientation of the device being imposed on him.

[0060] The interface allows working at all frequencies and not only at touch sensitivity frequencies between 150 Hz and 1000 Hz, however these are advantageous because they do not produce sound when activating the actuators. Thus different types of actuators can be used. Piezoelectric actuators are suitable for high and low frequency operation.

[0061] An example of "handling" the haptic device will now be described. The haptic device is, for example, integrated into a mobile phone, such as a smartphone. The user sets their smartphone to "Braille Input" mode, then positions it horizontally and begins a calibration phase. For example, they begin by quickly and simultaneously tapping with the index, middle, and ring fingers of their left hand and then their right hand. All six fingers are then calibrated on the screen. The control unit "knows" where the index, middle, and ring fingers of each hand are located on the screen and can then send signals to these locations to tactilely "display" the letters.

[0062] An example of the operation of this device will now be described in relation to the Figures 3A to 3C .

[0063] We want to tactilely display the d on the touch surface 2.

[0064] On the Figure 3A, we can see the transcription of the d in Braille. For this, the index finger of the left hand (point 1), the index finger of the right hand (point 4) and the middle finger of the right hand (point 5) must be stimulated.

[0065] On the Figure 3B , we can see the index, middle and ring fingers of each user's hand on the touch surface 2.

[0066] The control unit 6 detects the presence of the fingers and launches a finger tracking step in order to associate with each zone Z1, Z2, Z3, Z4, Z5, Z6 covered by each finger a finger and therefore a location in the three-row, two-column matrix of a Braille character.

[0067] For example, at the end of the locating step, the control unit 6 has associated zone Z1 with the index finger of the left hand, zone Z2 with the middle finger of the left hand, zone Z3 with the ring finger of the left hand, zone Z4 with the index finger of the right hand, zone Z5 with the middle finger of the right hand and zone Z6 with the ring finger of the right hand.

[0068] It may be provided to repeat this tracking step if the device detects that the user has removed all or part of his fingers from the surface during a time interval and therefore that the location of all or part of the fingers on the surface has changed.

[0069] The control unit then plays the d. The control means will calculate for each finger the signals to be sent to each actuator to generate tactile stimulation in zones Z1, Z4 and Z5. For the d, the index finger of the left hand, the index finger of the right hand and the middle finger of the right hand are stimulated.

[0070] On the Figure 3C, we can graphically see the amplitude of the vibrations as a function of time in zones Z1, Z4 and Z5. Thanks to the implementation of the inverse filtering method, the vibrations are localized and zones Z2, Z3 and Z6 are immobile. In this example, the amplitude of the vibrations and the duration of a stimulation are sufficient to be felt by the user. The vibration amplitude can reach, for example, 4 µm. In the example shown, the amplitude of the vibrations is of the order of 1 µm. The duration of the stimulation is long enough to be perceived by a user; it is, for example, between 200 ms and 500 ms.

[0071] By applying the inverse filtering method, only the fingers to be stimulated actually feel stimulation and the fingers are not stimulated by mistake since propagations and reverberations of the waves are avoided or at least strongly limited.

[0072] Very advantageously, the haptic device includes means to allow the user to act on the display of the letters. For example, means are provided to allow the display of the characters to be rewinded, for example to reread a word or a sentence or to slow down the display of the characters. For example, these means for acting on the scrolling of the characters include a wheel that can be manipulated by one of the thumbs, in fact the thumbs are not used in Braille reading. The wheel can be a mechanical wheel. Alternatively, it can be a tactile cursor.

[0073] According to this other example of operation of the haptic device, the haptic "display" of a character, more particularly of its points, is sequential, i.e. the haptic feedback of points 1, 4 and 5 of the Braille character are played offset in time in ascending order, i.e. point 1 before point 4 itself before point 5.

[0074] On the figure 4 , we can see the graphical representation of the amplitude of the vibrations as a function of time at the level of zones Z1, Z4 and Z5. The vibrations appear at different times in the different zones, the vibration of zone Z1 occurring before that of zone Z4 which occurs before that of zone Z5. The vibration of a zone is finished when the vibration of the following zone occurs. Sufficient time between the stimulations of two successive fingers is provided to allow the user to decode the information. In the example shown, the stimulation time is of the order of 200 ms and the time interval between two activated points is 200 ms. These times are indicative and the user will be free to change them at any time.

[0075] In the example shown, the amplitude of the vibrations is of the order of 1 µm and the duration of the stimulation is of the order of 200 ms.

[0076] The duration of the pulses and / or the time between two pulses and / or the amplitude of the stimulations can advantageously be adjusted by the user according to his habits and needs, for example when using the device for the first time.

[0077] According to another example of the operation of the haptic device, the points of a character are played two by two. For example, first points 1 and 4 are played, then points 2 and 5 and finally points 3 and 6. It will be understood that one or the other or neither of the points of each pair is or are translated by a vibration.

[0078] In the case of d, as shown in the Figure 5 , zones Z1 and Z4 are excited simultaneously, then only zone Z5 and finally neither zone Z3 nor zone Z6 are excited.

[0079] In the example shown, the amplitude of the vibrations is of the order of 1 µm and the duration of the stimulation is of the order of 200 ms.

[0080] In the reading examples described above, all areas are excited with the same amplitude, for the same duration, and with the same frequency. Alternatively, the areas are excited with different amplitudes and / or for different durations and / or with different frequencies. It may be considered to excite fingers with different frequencies to aid letter recognition.

[0081] Very advantageously, the haptic device also allows character input by the user, the device then operating in reading and writing.

[0082] For this, the device comprises means for measuring a pressure 10 exerted by each of the six fingers on the touch-sensitive surface, the control unit 6 having located the location of each of the fingers can deduce from the measurement of the pressures in the six zones the character to be “written”. For example, the means 10 for detecting the presence of the fingers on the touch-sensitive surface are further configured to measure the pressure exerted by a finger, or even comprise the means for measuring the pressure exerted by each finger on the surface. Preferably, the control unit 6 compares the pressure value exerted by each of the fingers to a threshold value below which it is considered that it is not a pressure exerted to generate a Braille character. Thus the user can permanently leave his fingers in contact with the surface without risking that this contact is considered as a pressure to generate a point of a Braille character.

[0083] According to one example, the pressure measurement can be carried out by means of force sensors, such as strain gauges, arranged on the periphery of the surface. The total force applied to the surface is then measured, as described in document US005241308 which describes a touch panel comprising strain gauges at its four corners, which makes it possible to detect the pressing force at four corners and to find the touched position and the corresponding force. According to another example, the local deformation of the touch surface is measured by means of a grid of electrodes located under the plate opposite the surface via a capacitive measurement. Such a grid of electrodes is described in documents US9349552 and US5510813 for position detection and force detection by a capacitive measurement.Alternatively, one may implement an array of force sensors distributed subsurface for multi-contact position and force sensing, as described in US 2010 / 0053116 A1.

[0084] The order of magnitude of the maximum pressure exerted by the user in Braille writing is of the order of 1 N.

[0085] To overcome the problems of hand drift as well as for involuntary keystrokes, algorithms have been developed. Such software is described for example in Shiri, WOBBROCK, Jacob O., PRASAIN, Sanjana, et al. Input finger detection for nonvisual touch screen text entry in Perkinput. In: Proceedings of graphies interface 2012. 2012. p. 121-129 .

[0086] Switching from reading mode to writing mode and vice versa can be controlled by a specific manipulation on the screen. For example, the user draws a semicircle on the screen with two fingers, causing a menu to appear in the form of a wheel. The user repeats the movement until the entry "Braille input" or "Braille reading" is read by a speech synthesis and selects Braille input or Braille reading.

[0087] Input can have several operating modes, just like reading. The user can press all the points of a character simultaneously, successively, or in groups.

[0088] The zones are then no longer zones for emitting a vibration but zones for capturing signals emitted by one or more fingers.

[0089] The present invention can then be easily integrated into portable devices such as mobile phones such as smartphones or touch tablets, but also into home automation devices, for example cooking hobs and other household appliances.

Claims

1. A haptic device for reading using the Braille-Perkins method including a plate (1) provided with a surface (2) with which at least the index finger, the middle finger and the ring finger of each hand of the user are intended to come into contact, actuators (A1, A2, An) fastened to the plate (1) opposite said surface (2), said actuators (A1, A2, An) being capable of generating a vibration at the surface in distinct areas, a control unit (6) for controlling said actuators (A1, A2, An), comprising means for computing the control signals implementing an inverse filtering operation, and configured to send control signals to all the actuators (A1, A2, An), the control unit (6) being configured to make n areas of the surface (2) vibrate, n being an integer comprised between 1 and 6, to stimulate the index finger, the middle finger and the ring finger of each hand of the user and reproduce by haptic stimulation the Braille characters using the Braille-Perkins method, each area corresponding to a dot of a Braille character.

2. The haptic reading device according to claim 1, wherein the control unit is configured to make the n areas vibrate simultaneously.

3. The haptic reading device according to claim 1, wherein the control unit is configured to make the n areas vibrate successively.

4. The haptic reading device according to claim 1, 2 or 3, including means (10) for detecting the presence of the index finger, the middle finger and the ring finger of each hand of the user and wherein the control unit (6) is configured to locate the position of the index finger, the middle finger and the ring finger of each hand of the user on the surface and record said positions.

5. The haptic reading device according to the preceding claim, wherein the detection means (10) include means for measuring the pressure exerted by each finger on the surface.

6. The haptic reading device according to one of the preceding claims, including means for controlling the display of the characters on the surface.

7. A haptic device for displaying and entering Braille characters using the Braille-Perkins method including a haptic reading device according to one of claims 1 to 6, wherein the control unit (6) is also configured to translate a measurement of the pressure exerted for each finger into a dot of a Braille character and to identify the Braille character.

8. A method for operating a haptic device for reading digital content given by a user according to one of claims 1 to 6, including: a) placing at least the index finger, the middle finger and the ring finger of each hand of the user on the surface of the device, b) translating the digital content into Braille characters, c) generating for each Braille character signals to all the actuators so they make n areas of the surface vibrate, said areas being covered by the index finger, the middle finger and the ring finger of each hand of the user.

9. The operating method according to the preceding claim, including between step a) and step b), a step of locating the location of the index finger, the middle finger and the ring finger of each hand of the user on the surface and of associating each of these fingers with said location.

10. A method for operating a haptic device for displaying and entering Braille characters using the Braille-Perkins method according to claim 7, implementing the steps of the operating method according to claim 8 or 9, and including: - measuring the pressure exerted by the index finger, the middle finger and the ring finger of each hand, - comparing with a threshold value, - translating the measurements into a dot of a Braille character and identifying the Braille character.