WO2025229373A1

WO2025229373A1 - An apparatus for speech recognition using tactile stimulation

Info

Publication number: WO2025229373A1
Application number: PCT/IB2024/054166
Authority: WO
Inventors: Evagoras XYDAS
Original assignee: Irerobot Ltd
Current assignee: Irerobot Ltd
Priority date: 2024-04-30
Filing date: 2024-04-30
Publication date: 2025-11-06
Anticipated expiration: 2026-10-30

Abstract

: A tactile stimulation device includes an elastomer body, a membrane surface, and a force generation. The membrane surface covers the elastomer body and comprises a plurality of pellets, in which various spatial patterns of maximum amplitudes are produced by the pellets at different radial distances from a centre of 5 a circular top surface of the elastomer body, when the elastomer body is excited at different input frequencies. The force generation module is aligned with the elastomer body and is configured to excite the elastomer body when the force generation module receives a tactile stimulation signal, so as to produce vibration nodes of the pellets, in which a combination of vibration nodes of maximum 10 amplitude by the pellets defines a specific tonotopic effect which represents a unique tactile signature for a specific phoneme.

Description

AN APPARATUS FOR SPEECH RECOGNITION USING TACTILE STIMULATION

Inventor: Evagoras XYDAS

Technical Field:

[0001] The present invention relates to speech recognition, in particularly to devices and methods for converting speech to tactile stimulation for recognition.

Background:

[0002] Hearing loss is a problem that affects millions of people. There are different degrees of hearing loss ranging from complete deafness from birth to diminished hearing due to aging. Hearing aids are sufficient for many people having impaired hearing but in more severe cases such as for people who are fully deaf, hearing aids are usually not able to help them perceive speech or music. People who are both deaf and blind have even greater challenges in communication.

[0003] Deaf people can benefit from tactile stimuli that are associated with sound. Tactile stimuli may be conveniently provided on a particular skin area of the hand for example. The use of tactile devices as a substitute for audition is dependent on the efficacy of phonemic recognition via tactile signals alone. Several studies verify that vibrotactile aids can enable deaf people to detect segmental and suprasegmental features of speech, and the discrimination of common environmental sounds. Existing vibrotactile aids provide very useful information regarding speech and nonspeech stimuli. However, this is not enough. It is necessary to provide the means for accurate speech recognition so that deaf people would be able to understand the meaning of what is being said. There is a need for a device or system that provides sound-to-tactile stimulation that enables the distinction of vowels.

[0004] There are several devices known to provide haptic communication through the generation of vibrations. Many of these devices utilize cutaneous actuators to transmit vibrations. For example, U.S. Patent No. 10,222,864B2 teaches a method that operates with cutaneous actuators to enhance haptic communication through a path on the receiving user’ s skin by using constructive or destructive interference between haptic outputs. The cutaneous actuators, spaced apart from each other on a patch of skin, generate haptic outputs in such a way that the generated haptic outputs constructively or destructively interfere with the patch of skin. [0005] Moreover, there are other approaches that generate tactile vibrations comprising of utilization of electroactive transducers. For example, the European Patent Application Publication No. EP2353066A4 teaches the actuation of an electroactive polymer transducer and how to simultaneously drive the haptic effect with the sound generated by the audio signal.

[0006] Further, there are other means comprising multiple tactile pixels that are actuated with solenoid actuators. PCT International Patent Application Publication No. W02021079101 Al discloses such a system in which each tactile pixel (referred to as “taxels”) is actuated by a solenoid and made to vibrate. Two “taxels” have different resonant frequencies and vibrate in ways to create a tactile sensation that corresponds to a message.

[0007] Systems like the ones outlined above at least have three major disadvantages:

(a) inadequate resolution and in turn low capability to distinguish speech;

(b) insufficient useability consideration for the user to learn how to distinguish tactile stimuli in a consistent way that corresponds to specific phonemes; and

(c) bulkiness of the device and in turn impracticality of wearing such bulky device for everyday use.

[0008] Therefore, there is a need for a device that can convert speech to tactile stimulation with sufficient tactile resolution to allow the user to easily distinguish different phonemes and consistently understand the intended meaning of speech, while being compact so that it can be worn comfortably in everyday use.

Summary of Invention:

[0009] It is an objective of the present invention to provide systems and methods to address the aforementioned shortcomings and unmet needs in the state of the art.

[0010] The present invention accommodates a device for sound to tactile stimulation that enables deaf people to perceive and distinguish different sounds so that, with training they can understand the meaning of speech and be able to utilize tactile sensory input as a substitute to auditory sensory input.

[0011] Embodiments of the present invention provide a device that detects speech sounds and converts these sounds into haptic stimuli, resulting in the tactile stimuli generated by a Tactile Stimulation Body (TSB) having a number of different modes of vibration. The TSB includes a surface that can vibrate. The surface is in contact with the skin of the user and the vibration nodes on the surface are generated according to a number of different stimulation frequencies.

[0012] The TSB is excited by a voice-coil actuator (VCA) responsible for converting sound to tactile stimulation signals. Upon excitation, the TSB vibrates in different vibration modes so that displacement-peaks form in ways that create a clear signature for each vowel. In one embodiment, the form of the signature is such that each vowel is represented by three pairs of frequencies, and each pair of frequencies corresponds to each of the three audio formant frequencies characterising each vowel. Profiles with displacement-peaks then form the distinct signature for each vowel.

[0013] The TSB, upon excitation, causes the surface to vibrate in different modes so that displacement-peaks form in a way that creates a clear signature for each phoneme. A clear spatial signature for each phoneme is a key requirement for users to be able to easily perceive and differentiate one phoneme from another. Profiles with displacement-peaks form distinct spatial signatures of each phoneme as corresponding to the audio formant frequencies which are transformed, through the signal processing, to the corresponding tactile excitation frequencies.

[0014] In this regard, the variation in vibration amplitudes of the surface of the elastic body manifests itself through two separate modes of vibration:

1. The modal response or natural response, which is a result of the dynamic properties of the structure (mass, elasticity, and damping) and that decays and dies- out due to the damping properties of the materials.

2. The steady-state vibration which is purely a result of harmonic excitation and persists for as long as the external excitation is ongoing.

[0015] Due to the dynamic and quick-changing nature of excitation through speech, the result is an interplay between modal (natural) response and steady-state response. Ultimately a different spatial signature in terms of amplitudes is achieved for each superposition of excitatory signals.

[0016] In accordance with a first aspect of the present invention, a tactile stimulation device is provided that includes an elastomer body, a membrane surface, and a force generation module. The membrane surface covers the elastomer body and comprises a plurality of pellets. Various spatial patterns of maximum amplitudes are produced by the pellets at different radial distances from a centre of a circular top surface of the elastomer body when the elastomer body is excited at different input frequencies. The force generation module is aligned with the elastomer body and is configured to excite the elastomer body when the force generation module receives a tactile stimulation signal, so as to produce vibration nodes of the pellets, in which a combination of vibration nodes of maximum amplitude by the pellets defines a specific tonotopic effect which represents a unique tactile signature for a specific phoneme.

[0017] In accordance with a second aspect of the present invention, a device for tactile stimulation is provided and includes a TSB implemented by using the tactile stimulation device as afore-described, a tactile stimulation applicator, at least one strap, and an electronic control box. The tactile stimulation applicator is coupled with the TSB. The electronic control box is connected to the tactile stimulation applicator through the strap and incorporates a microphone. The electronic control box is configured to convert audio signals which are formed from received sound by the microphone to a series of tactile stimulation signals, in which each of the series of the tactile stimulation signals corresponds to a specific phoneme. The electronic control box is further configured to transmit the tactile stimulation signals to the tactile stimulation applicator via the strap, such that the tactile stimulation applicator enables to trigger the TSB.

[0018] In one embodiment, the elastomer body of the TSB is a silicone elastomer body in a cylindrical or frustoconical form, and is made of silicone elastomer material. The upper surface of the TSB further comprises small steel metal balls (pellets) distributed and embedded on the surface.

[0019] The structure of the TSB is such that, for different excitation frequencies, there are topologically (namely radially) different distributions of peak amplitudes. In one embodiment, this is achieved by varying the thickness of the elastic/elastomer body radially and/or by embedding stainless steel pellets of different masses at different radii. The different structural characteristics enable varying dynamic characteristics. The elastic/elastomer body is excited by a small voice coil which is in contact with a conical housing in which the silicone elastomer material of the elastic/elastomer body is supported.

Brief Description of Drawings:

[0020] Embodiments of the invention are described in more details hereinafter with reference to the drawings, in which: [0021] FIG. 1 is an illustration of basic symmetric vibrations at the top of a surface of a circular thin elastic body according to one embodiment of the present invention; [0022] FIG. 2 is an illustration of an example of modal forms of circular elastic body that is thin and homogenous according to one embodiment of the present invention; [0023] FIG. 3 is an illustration of patterns of membrane excitation under different frequencies for a thin elastic body that comprises a plurality of embedded pellets;

[0024] FIG. 4A depicts a schematic diagram of a cross-section of a TSB according to one embodiment of the present invention;

[0025] FIG. 4B depicts a schematic diagram of a cross-section of a TSB according to another embodiment of the present invention;

[0026] FIG. 4C depicts a schematic diagram of a cross-section of a TSB according to another embodiment of the present invention;

[0027] FIG. 4D depicts a schematic diagram of a top view of a TSB according to another embodiment of the present invention;

[0028] FIG. 4E depicts a schematic diagram of a top view of a TSB according to yet another embodiment of the present invention;

[0029] FIG. 5A and FIG. 5B are schematic diagrams showing a silicone elastomer cast inside a frustoconical housing made of either paper or plastic according to various embodiments of the present invention;

[0030] FIG. 6 depicts a schematic diagram of a model of a device with an elastomer and pellets as springs and dampers;

[0031] FIGS. 7A, 7B, and 7C depict the schematic diagrams of the various views of a structure of a TSB according to one embodiment of the present invention;

[0032] FIG. 8 is an exemplary illustration of the steady state response of the surface of the elastic body under different excitation frequencies;

[0033] FIG. 9A is an exemplary illustration of the excitation of the surface of the elastic body under several excitation frequencies;

[0034] FIG. 9B is another exemplary illustration of the excitation patterns of the surface of the elastic body under several excitation frequencies;

[0035] FIG. 10 is an exemplary illustration of the contrast of the excitation patterns produced on the surface of the elastic body under similar excitation frequencies;

[0036] FIG. 11 shows the comparative illustrations of modal shapes produced by different excitations;

[0037] FIG. 12 is an illustration of the anatomical conventions of the hand; [0038] FIG. 13 A and FIG. 13B show the areas of the palm where the TSB is contacting the skin according to various embodiments of the present invention;

[0039] FIG. 14 depicts a schematic diagram showing the placement of the device for tactile stimulation on the hand according to one embodiment of the present invention;

[0040] FIG. 15A and FIG. 15B depict the schematic diagrams showing the placement of the device for tactile stimulation according to some embodiments of the present invention; and

[0041] FIG. 16 depicts a schematic diagram showing a combination of a TSB, straps, and an electronic control box according to one embodiment of the present invention.

Detailed Description of the Invention:

[0042] In the following description, apparatuses for converting speech to tactile stimulation for recognition and the likes are set forth as preferred examples. It will be apparent to those skilled in the art that modifications, including additions and/or substitutions may be made without departing from the scope and spirit of the invention. Specific details may be omitted so as not to obscure the invention; however, the disclosure is written to enable one skilled in the art to practice the teachings herein without undue experimentation.

[0043] Referring to FIG. 1 for the following description. According to one embodiment of the present invention, the transmission of vibrations is achieved via the circular surface of an elastic body 10. This circular surface is part of the Tactile Stimulation Body (TSB). The elastic body 10, in one embodiment, comprises at least a silicon elastomer. Under usage, the user can sense the vibration patterns on the top surface of the elastic body 10. Excitation of the elastic body 10 produces different vibrations, some of which may be symmetric, and others asymmetric. However, as illustrated by FIG. 1, the modes of vibration 101 and 102 do not contain sufficient information to enable a user to distinguish between one phoneme from another.

[0044] Referring to FIG. 2 for the following description. In this exemplary representation, the eigenmode of such a homogeneous elastic body 12 at 200Hz is shown. Three main peaks 103 and three secondary peaks 104 can be seen from FIG. 2. Even though it is a significant improvement in comparison to that in the illustration of FIG. 1, there is still insufficient information for a user to be able to clearly distinguish various phonemes.

[0045] Referring to FIG. 3 for the following description. The top surface of the TSB’s circular elastic body 100 includes plurality of embedded pellets 105. As the elastic body 100 being excited by an excitation mechanism, the embedded pellets 105 on the surface of the elastic body 100 receive maximum amplitudes in different locations through the membrane depending on the excitation frequency. FIG. 3 illustrates six excitation frequencies according to one embodiment, namely, 100Hz, 290Hz, 360Hz, 370Hz, 410Hz, and 420Hz. In these illustrations, the darker the color on the images, the greater the amplitudes of vibration. The black-colored peaks 105 represent points of peak amplitudes. It is the specific spatial arrangement of these peaks that constitutes the distinct signature for a phoneme. The greater the number of distinguishable signatures, the greater the resolution of a tactile stimulation device in its ability to represent sounds by tactile stimulations. The resulting amplitudes of vibration for each excitation frequency fall within the range detectable by Pacinian corpuscles. The Pacinian corpuscles act as the mechanoreceptors inside the skin that are mainly responsible for detecting vibrations. The pellets 105 can provide a better vibratory texture.

[0046] In this regard, sounds are characterized by different frequency values, which in turn excite the elastic body 100 in unique ways. Alternative spatial patterns of maximum amplitudes at different radial distances from the center of the circular surface of the elastic body 100 can be created when the elastic body 100 is excited at different input frequencies. FIG 3 is an illustration that explains the core principles of the phenomenon. These illustrations can be generated by computer simulations. The chosen frequencies (i.e., 100Hz, 290Hz, 360Hz, 370Hz, 410Hz, and 420Hz) give maximum amplitudes at different radii on the circular surface of the elastic body 100, at locations where the pellets 105 are present. Frequencies, which produce maximum amplitudes or peaks, are different for different specific arrangements/conditions of geometry, pellet arrangement and mass (i.e., the pellets 105), and thickness of the elastic body 100 of the TSB according to various embodiments. It is possible to fine-tune the construction of the TSB (i.e., the arrangements/conditions for the pellets 105) to achieve an optimum range of tactile signatures for phonemes so that they can most easily be recognized by the majority of users. [0047] Referring to FIG. 4A for the following description. In one embodiment, the TSB includes a base 14, a force generation module 400, and a thin elastic body 300. The force generation module 400 is positioned below the thin elastic body 300 and between the base 14 and the thin elastic body 300. Between the force generation module 400 and the thin elastic body 300 is an interface with a gap of zero up to a few hundred microns in thickness. In one embodiment, the force generation module 400 receives the digital signals for generating the corresponding sound waves or analog signal waves of other forms, in turn producing controlled vibrations into elastic materials (i.e., the thin elastic body 300). In one embodiment, the force generation module 400 includes one or more voice-coil actuators (VCAs) with coils for generating sound waves.

[0048] Referring to FIG. 4B for the following description. In another embodiment, the TSB 200B includes a thin elastic body 300 having pellets 302 positioned over the force generation module 400. The pellets 302 are distributed on a top surface of the thin elastic body 300. In one embodiment, the TSB 200B is in a cylindrical form having a circular or elliptical top surface. The pellets 302 have a distance D between their centers. In one embodiment, the distance D ranges between 3mm and 7mm. [0049] Referring to FIG. 4C for the following description. In another embodiment, the elastic body 300 of the TSB 200C includes a silicone body 301 and pellets 302 and is in a frustoconical form 310. In one embodiment, the diameter DI of the top surface of the silicone body 301 ranges between 40mm and 50mm; for example, is about 45mm. In one embodiment, the diameter D2 of the bottom surface of the silicone body 301 ranges between 10mm and 15mm; for example, at about 13mm. In one embodiment, the height H of the silicone body 301 ranges between 3mm and 6mm; for example, is about 4.1mm. The pellets 302 are partially or entirely embedded in the top surface of the silicone body 301. In one embodiment, the pellets 302 include small stainless-steel balls with a desired diameter (i.e., about 2mm). The pellets 302 are embedded at an adequate depth so that they are held in place by the adhesive forces asserted by the material of the silicone body 301 of the elastic body 300. In one embodiment, the silicone body 301 of the elastic body 300 optionally include a silicone elastomer of low shore hardness.

[0050] Referring to FIG. 4D for the following description. In another embodiment, the TSB 200D includes an elastic body 300 with a silicone body 301 and pellets 302 positioned on the top surface of the silicone body 301. The arrangement of the pellets 302 on the top surface is symmetric and homogeneous. According to this embodiment, all the pellets 302 are identical, made of the same material and have the same diameter. They are evenly spaced in a regular pattern within the top surface of the silicone body 301, which has a diameter D3 ranging between 40mm and 50mm; for example, at approximately 45 mm.

[0051] Referring to FIG. 4E for the following description. In yet another embodiment, the TSB 200E includes an elastic body 300 with a silicone body 301 and pellets 302 positioned on the top surface of the silicone body 301. The arrangement of the pellets 302 positioned on the top surface of the silicone body 301 is not homogeneous. In this embodiment, the pellets 302 contain of two or three different types of material and/or diameter, such as pellets 303, 304, and 305. The arrangement of different types of pellets 302 is done in relation to radial distance from the center of the circular surface of the silicone body 301.

[0052] In one embodiment, the pellets 302 of higher mass are placed closer to the center. In an alternative embodiment, the pellets 302 of lower mass are placed closer to the center. The pellets 302 are spaced within the top surface of the silicone body 301, which has a diameter D4 ranging between 40mm and 50mm; for example, at approximately 45mm.

[0053] In one embodiment, the pellets 302 are arranged in concentric circles. The number of pellets 302 on the surface and the distance between pellets 302 (i.e., the distance D) is selected to provide the desired natural frequencies, in turn the desired nodes at specific frequencies. In one embodiment, the pellets 302 are embedded within the material of the elastic body 300, at a small distance from the surface.

[0054] In another embodiment, the pellets 302 are secured on top of the material of the elastic body 300, at the surface. In such embodiment where the pellets 302 are secured at the surface of the elastic body 300, the placement takes place when the material of the elastic body 300, preferably a silicone elastomer (i.e., the silicone body 301), is still in liquid form before solidifying, so that the adhesions of the pellets 302 to the elastic body 300 is by the adhesive forces of the elastomer itself. The material of the pellets 302 may vary.

[0055] In one embodiment, the pellets 302 are made of steel, such as stainless steel. This is because the higher specific mass of metal creates a segmentation of the surface that generates a richer response with vibration nodes. [0056] In another embodiment, the pellets 302 are made of the same material as the elastic body and are formed integrally as the silicon elastomer of the membrane is moulded, as spherical formations of the surface.

[0057] Herein, in the context of the specified term of “the silicone body 301,” it is important to note that, depending on various conditions or specific requirements, the silicone body 301 is changeable. The replacement material should be elastic and may encompass materials other than silicone or composite materials that include silicone. This flexibility in material substitution allows for adaptation to diverse needs or environmental considerations, providing versatility in the composition of the elastic body based on distinct criteria. In one embodiment, the material of the pellets 302 is stainless steel. In an alternative embodiment, the material of the pellets 302 is aluminum or aluminum alloy.

[0058] In one embodiment, the silicone body 301 has the following properties: shore hardness at about 20A, specific gravity at about 1.07g/cc, and tensile strength at about 160 psi. In one embodiment, the silicone body 301 is cast in liquid form directly on the cone of the VCA (e.g., a Voice-Coil Actuator of the miniature speaker 400) and any air bubbles are removed. The cone of the VCA (i.e., a Voice-Coil Actuator) is typically made of paper or thin plastic material. In an alternative embodiment, air bubbles are intentionally allowed in the volume of the silicone body 301 to change the specific gravity of the material. This produces a different dynamic response and alternative modes of vibration.

[0059] The diameter of the top circular surface of the elastic body 300 is selected to be from about 40mm to 50mm, preferably about 45mm in one embodiment. This diameter is chosen in relation to ergonomics and sensitivity for tactile perception at the human hand. It is estimated that there are around 800 Pacinian Corpuscles in the palm area, and they are mainly located in the hypothenar region. In one embodiment, when the TSB (i.e., TSB 200A-200E) is in contact with the palm, the diameter of the silicone, which is in contact with the palm, can cover the hypothenar region for providing the user with full sound to tactile experience. Based on the anthropometric measurements for 50 percentile man and woman, the maximum diameter of the silicone is around 45mm, and the minimum is around 38 mm, for covering the whole hypothenar region both for men and for women. In one embodiment, the maximum diameter of 45mm is used to achieve a higher resolution of vibrations and a more accurate sound to tactile conversion. In one embodiment, utilization of a diameter of 45mm for the top surface of the elastic body 300 allows the placement of an optimal number of pellets 302 to achieve a high resolution of vibrations.

[0060] Referring to FIGS. 5A and 5B for the following description. Both of the structures as shown in the figures include elastic bodies 300 with elastomer inside (i.e., silicone body 301) in conical shapes. In one embodiment, the silicone elastomer (i.e., silicone body 301) is cast inside a frustoconical housing made of either paper or plastic. According to the embodiment shown in FIG. 5A, the conical membrane/housing 403 has the same structure as the cone of the miniature VCA. This frustoconical membrane/housing 403 is excited by a vibrating coil 402 from beneath. The vibrating coil 402 is in one embodiment the coil of a miniature VCA. In FIG. 5B, the silicone elastomer (i.e., silicone body 301) is cast into a frustoconical membrane/housing 403 (made of paper or thin plastic material). This structure (elastomer and plastic housing) is in contact with the coil and/or the membrane 404 of the miniature VCA 402. The overall structure of the TSB 200F or 200G is supported by an external housing 210. Further, when silicone elastomer (i.e., silicone body 301) is cast on top of cone of the VCA 402 within the membrane/housing 403, to form the elastic body, there is very good adhesion, partly due to the inherent roughness of the pulp material (paper) that the cone membrane/housing 403 near the top of the VCA 402 is typically made of.

[0061] The TSB, as illustrated in FIGS. 4A-4E and 5A-5B, includes: a frustoconical elastomer body of silicone elastomer (i.e., silicone body 301); an optional housing (i.e., membrane/housing 403) of the frustoconical elastomer body housing made of resin or plastic; a coil for exerting an excitation force (i.e., VCA 402), in which the coil, in one embodiment, can exert a max force of 0.5N (excitation force amplitude); spherical pellets (i.e., pellets 302) embedded onto the top surface of the silicone elastomer, in which the top surface is the surface that is in contact with the user’s skin (i.e., SKIN in FIG. 5 A or 5B).

[0062] In one embodiment, the pellets 302 are stainless-steel (AISI Type 316L) with a diameter preferably of 2mm. The distance between pellets 102 is preferably 3.2mm in both the radial and tangential directions. The pellets 302 are partially embedded on the surface of the silicone elastomer (i.e., silicone body 301). The distance between the centers of the pellets 302 for pellets 302 of 2mm diameter is, in one preferred embodiment, of 3 ,2mm. The distance between the centers of pellets 302 may vary from 2mm to 5mm depending on the diameter of the pellets 302. This is related to the perception of roughness at skin contact. Distance between centers of pellets 302 is an important feature for achieving Just Noticeable Differences (JND) for different excitation frequencies corresponding to different vowels.

[0063] Referring to FIG. 6 for the following description. In this model, the pellets 302 are considered as connected to two or more parallel springs, having spring constants Ki, K2. . Kn, and subjected to damping by dampers C. This model can be used to model the behavior for different masses or pellets. The elastic material of the silicone elastomer 301 itself exhibits both an elastic and a damping characteristics. The different elasticities of the material at different radial distances are modelled by spring constants Ki, K2 wherein K2>KI.

[0064] Referring to FIGS. 7A-7C for the following description. The TSB 200H includes pellets 302 on the top surface of the elastic body 300. In the TSB 200H, the elastic body 300 includes a silicone elastomer 301 in a frustoconical shape. In one embodiment, the silicone elastomer 301 and the pellets 302 of the elastic body 300 serve as a tactile excitation body for the TSB 200H. The elastic body 300 is in contact with a VCA membrane 403 and the coil of a VCA 402 provides the excitation force. The VCA 402 and the elastic body 300 are supported by the exterior housing 210. The exterior housing 210 includes at least one aperture 211 so that air can flow freely between the ambient environment and the VCA membrane 403.

[0065] The top surface of the elastic body 300 has a circular shape. In one embodiment, the silicone of the silicone elastomer 301 is cast in a liquid form, directly on the VCA membrane 403, and so it receives its shape. In one embodiment, the pellets 302 are placed on the top surface of the membrane 403 whilst the silicone is still non-fully solidified. The pellets 302 are then partly sunk into the silicone and the silicone material bonds to the material of the pellets 302. In one embodiment, an additional thin layer of the silicone elastomer 301 is applied onto the surface immediately after placement of the pellets 302.

[0066] During the operation for the converting speech to tactile stimulation, when a sinusoidal input is applied to the coil of the VCA 402, the VCA's cone starts to oscillate and it transfers its vibration onto the bottom of the elastic body 300 with which it is in contact. As a result, the elastic body 300 starts to oscillate also, forming various shapes for the desired recognition on its surface where the pellets 302 are embedded therewithin.

[0067] Referring to FIG. 8 for the following description. The maximum amplitudes that appear in different locations radially, based on the excitation frequency are shown in the figure. For an excitation frequency of 100Hz, the maximum amplitudes appear in the four pellets 302 in the middle of the silicone. For an excitation frequency of 230Hz, the maximum amplitudes appear in the four pellets 302 in the middle of the silicon and to the circle with the pellets 302 next to them. For an excitation frequency of 330Hz, maximum amplitudes appear in the second circle from the inside part of elastic body. For excitation frequencies of 370Hz and above, the maximum amplitudes exist in some more complicated forms. The solid black line (i.e., lines 106a-106f) illustrates the spatial relationship of the pellets 302 with the maximum amplitude; and the peak amplitudes of pellets 105 are shown. This spatial relationship is the key feature of the unique signature for a phoneme to be perceived by the Pacinian corpuscles.

[0068] FIG. 9A is an illustration of the excitation of the surface of the elastic body under several excitation frequencies for the vowel phoneme /o:/ according to one embodiment of the present invention. The excitation frequencies are based on the phoneme frequencies of vowel /o:/. FIG. 9B is an illustration of the excitation patterns of the surface of the elastic body under several excitation frequencies for the vowel phoneme /u:/ according to one embodiment of the present invention. The excitation frequencies are based on the phoneme frequencies of vowel /u:/.

[0069] When focusing on speech, as opposed to other sounds, each vowel is characterized by a combination of three frequencies. A phoneme is characterized by a combination of frequencies, which when transformed to tactile excitation frequencies via certain transfer function, results in several excitation frequencies at which the TSB is excited. The combination of these excitation frequencies as applied to the TSB provides for each vowel creates its unique signature of tactile stimulation.

[0070] FIG. 8 is an illustration of the shape of the top surface of the elastic body for each individual stimulation frequency, based on the output of simulation software, that together create a spatial signature; and, FIG. 9A and FIG. 9B show the examples, from software simulations, of the excited elastic body under different excitation frequencies related to the illustrated examples to the phonemes for vowels /o:/ and /u:/. The user experiences for each vowel phoneme a unique tactile signature that is the combination of the spatial signatures for each of the excitation frequencies in the group of excitation frequencies related to a particular phoneme.

[0071] In one embodiment of the present invention, the perception to the user of different phonemes is further enhanced by using pellets (i.e., pellets 302) of different diameters and/or different masses. The user’s perception of different phonemes is associated with the tonotopic effect, essentially reflecting differences in the topological distribution of amplitudes. The position of the maximum amplitude for various frequencies is known as the tonotopic effect. In one embodiment, the tonotopic effect is heightened through a pellet arrangement illustrated in FIG. 4E. Pellets are arranged in concentric circles in this embodiment. The diameter of the pellets in the inner circle is about 2 mm, moving radially outward, the next circle consists of pellets with a diameter of about 1 mm, followed by another circle with pellets of about 1.5mm in diameter, and finally, the outermost circular arrangement consists of pellets with an about 2mm diameter. This order is determined by the observed areas that are activated during vibration.

[0072] FIG. 10 is an illustration of the contrast of the excitation patterns produced on the surface of the elastic body under similar excitation frequencies for the vowel phoneme /u:/ and the vowel phoneme /i:/ according to one embodiment of the present invention. The combination of phoneme frequencies of vowel /i:/ can give a different shape to the surface in comparison with the combination of phoneme frequencies for /u:/ vowel that will give. Modal analysis provides information about the mode shapes of the system, which are the patterns of vibration that occur at each natural frequency, and they help to understand how the system will deform. FIG. 10 represents an example of the modal shapes of the elastic body, for the vowel phonemes /i:/ and /u:/. Each vowel consists of a combination of phonemes’ frequencies. For each phoneme, the elastic body receives maximum amplitudes in different locations in the radial direction of the top surface of the elastic body. As a result, the combination of the elastic body’s surface shapes for /i:/ vowel, results in a different form than the one that will be extracted from the combination of frequencies for the /u:/ vowel. In this way, the pellets 302 are able to produce different pattems/profiles in response to different inputs from VCA 402, thereby giving different tactile feedback for users. [0073] In the afore-described embodiments, the elastomer body of the TSB is frustoconical with a circular top surface. These are preferred geometries because of the inherent symmetry. Tactile stimulation bodies with a circular top surface can produce more differentiated modal shapes than tactile stimulation bodies with other shapes for their top surfaces.

[0074] FIG. 11 shows the comparative illustrations of modal shapes produced by the excitation of an elastic body having a rectangular upper surface in contrast to the modal shapes produced by an elastic body having a circular upper surface. The bottom surface of the elastic body in both cases remains circular. In the above description, focuses are placed on tactile stimulation bodies having a circular upper surface according to various embodiments of the present invention. There are, however, circumstances where it may be beneficial to utilize a TSB and a corresponding elastic body having a rectangular upper surface. The same principles of the present invention apply as well.

[0075] FIG. 11 shows the comparison between orthogonal interface (left), the circular interface with conical shape on the bottom (middle), and the circular interface that has the shape of the VCA’s membrane below (right), where very different modal shapes can be observed. The examples represent excitation frequencies corresponding to the 1st phonemes’ frequency for the vowels /a:/, /s:/, and /i:/. Each elastic body of different geometry adopts distinct shapes of the top surface for different frequencies. This phenomenon is due to the selected silicone, the EcoFlex00-20, being very elastic with low shore-hardness and low damping. The pellets on top of the elastic body react as independent mass-spring damper and they make the eigenmodes more distinguishable between each other. However, in general, the eigenmodes that the circular top surface can receive are almost the same, only the frequency for each mode differs. Eigenmodes vary little with different diameters or thicknesses of the silicone; and the waves are distributed in a circular form.

[0076] For at least one embodiment of the present invention, the displacement of the TSB is in the coronal direction of the hand. The device according to this embodiment causes small scale deformation on the coronal plane of the hand, whereas the deformation on the transverse plane is insignificant.

[0077] In this regard, FIG. 12 is an illustration of the anatomical conventions of the hand. The maximum deformation on the coronal plane achievable is around 0.0353mm, while the minimum is around 0.0013mm. This is significantly higher than the just-noticeable-difference for amplitude on the palm, which is around lOnm. [0078] In one embodiment, the device for tactile stimulation (i.e., TSB 200A-200H) is placed on the palm for the user. FIG. 13 A and FIG. 13B show the areas of the palm where the TSB (i.e., TSB 200A-200H) is contacting the skin according to various embodiments of the present invention. In one embodiment, the TSB is in contact with the Thenar region 420. In another embodiment, the TSB is in contact with the Hypothenar region 430 of the hand where there is a higher concentration of Pacinian corpuscles. Placement near the Hypothenar region 430 is an optional embodiment because of higher density of Pacinian corpuscles, which means that there is greater sensitivity to tactile stimulation. In another embodiment, the TSB is in contact with the region 440 while in yet another embodiment the TSB is in contact with the region 450.

[0079] Referring to FIG. 14 for the following description. A tactile stimulation applicator 500, which is implemented by using the TSB (i.e., TSB 200A-200H) and contacts an area on the palm, is held in place using straps 600 that ties the tactile stimulation applicator 500 to the electronic control box 700. The strap 600 can be adjusted to the size of the hand of the user so that the tactile stimulation applicator 500 is arranged at the desired region of the palm for greater sensitivity and for convenience according to user preferences.

[0080] In an alternative embodiment, the device for tactile stimulation may be attached to the hand in such a way that it can appear as a smart watch. This makes it more discreet, and it frees the hand for other motor functions. For these reasons some users may find it being a preferable placement. FIG. 15A and FIG. 15B show such placement according to some embodiments of the present invention. In the present embodiment, the electronic control box 700, which acts as a signal processing and power unit, is in the form of a smart watch, while the tactile stimulation applicator 500 is positioned to be in contact with the lower region of the wrist as shown in FIG. 15A or in contact with the upper region of the wrist as shown in FIG. 15B.

[0081] FIG. 16 shows a combination of a TSB, straps, and an electronic control box according to one embodiment of the present invention. A device for tactile stimulation includes a TSB 200, a tactile stimulation applicator 500, at least one strap 600, and an electronic control box 700 which can serve as a signal processing and power unit. TSB 200 can be implemented by optionally choosing one of the TSB 200A-200H. The straps 600 provide mechanical fastening for supporting the TSB 200 at a minimum pressure against the user skin, securing the device on the user’s hand. The electronic control box can house all electronics for receiving an audio signal and converting it to a tactile stimulation signal. Electrical communication between the electronic control box 700 and the tactile stimulation applicator 500 takes place via electrical wires, which are integrated into the strap 600. The electronic control box 700 includes a microphone 701 and a user interface 702. It further includes electronics, battery, wireless communication, and an electrical connection to the tactile stimulation applicator 500. A controller in the electronic control box 700 ensures fixed latency between input and output. In one embodiment, a COTS microcontroller is used, and the hardware is BELA mini. Bela is a CAPE for Beaglebone black mini-computer and works under Xenomai protocol that ensures fixed latency between input and output.

[0082] Specifically, during an operation for tactile stimulation, the electronic control box 700 is configured to convert audio signals (i.e., the received sound by the microphone 701) to a series of tactile stimulation signals, in which each of the series of the tactile stimulation signals corresponds to a specific phoneme. Then, the tactile stimulation signals are transmitted from the electronic control box 700 to the tactile stimulation applicator 500 via the strap 600, and thereafter the tactile stimulation applicator 500 can correspondingly trigger the TSB 200. When a tactile stimulation signal is fed to a voice-coil actuator (VCA)of the TSB 200 by the tactile stimulation applicator 500, a silicon elastomer body of the TSB 200 can be excited by the VCA, thereby producing vibration nodes of pellets (i.e., the afore-described pellets 302) of the TSB 200. The pellets are distributed throughout a membrane surface that is placed in contact with user skin. In this regard, a combination of vibration nodes of maximum amplitude defines a specific tonotopic effect which represents a unique tactile signature for a specific phoneme that enables a user to perceive and distinguish that phoneme. As such, with some training, the user can perceive speech.

[0083] The functional units and modules of the apparatuses and methods in accordance with the embodiments disclosed herein may be implemented using computing devices, computer processors, or electronic circuitries including but not limited to application specific integrated circuits (ASIC), field programmable gate arrays (FPGA), microcontrollers, and other programmable logic devices configured or programmed according to the teachings of the present disclosure. Computer instructions or software codes running in the computing devices, computer processors, or programmable logic devices can readily be prepared by practitioners skilled in the software or electronic art based on the teachings of the present disclosure.

[0084] All or portions of the methods in accordance to the embodiments may be executed in one or more computing devices including server computers, personal computers, laptop computers, mobile computing devices such as smartphones and tablet computers.

[0085] The embodiments may include computer storage media, transient and nontransient memory devices having computer instructions or software codes stored therein, which can be used to program or configure the computing devices, computer processors, or electronic circuitries to perform any of the processes of the present invention. The storage media, transient and non-transient memory devices can include, but are not limited to, floppy disks, optical discs, Blu-ray Disc, DVD, CD- ROMs, and magneto-optical disks, ROMs, RAMs, flash memory devices, or any type of media or devices suitable for storing instructions, codes, and/or data.

[0086] Each of the functional units and modules in accordance with various embodiments also may be implemented in distributed computing environments and/or Cloud computing environments, wherein the whole or portions of machine instructions are executed in distributed fashion by one or more processing devices interconnected by a communication network, such as an intranet, Wide Area Network (WAN), Local Area Network (LAN), the Internet, and other forms of data transmission medium.

[0087] The foregoing description of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations will be apparent to the practitioner skilled in the art.

[0088] The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated.

Claims

Claims: What is claimed is:

1. A tactile stimulation device, comprising: an elastomer body; a membrane surface covering the elastomer body and comprising a plurality of pellets, wherein various spatial patterns of maximum amplitudes are produced by the pellets at different radial distances from a center of a circular top surface of the elastomer body when the elastomer body is excited at different input frequencies; and a force generation module aligned with the elastomer body and configured to excite the elastomer body when the force generation module receives a tactile stimulation signal, so as to produce vibration nodes of the pellets, wherein a combination of vibration nodes of maximum amplitude by the pellets defines a specific tonotopic effect which represents a unique tactile signature for a specific phoneme.

2. The tactile stimulation device according to claim 1, wherein the elastomer body comprises a silicone elastomer comprising an elastic material of shore hardness between 10A shore to 30A shore.

3. The tactile stimulation device according to claim 1, wherein the elastomer body comprises a silicone elastomer in a frustoconical shape and having a thickness between 3.5mm and 6mm.

4. The tactile stimulation device according to claim 1, wherein the membrane surface has a diameter ranging from 30mm to 50mm.

5. The tactile stimulation device according to claim 1, wherein the elastomer body comprises a silicone elastomer and is formed by direct casting of liquid silicone onto a surface of a voice-coil actuator (VCA) connecting to the elastomer body.

6. The tactile stimulation device according to claim 1, wherein the pellets are arranged over the elastomer body in circular patterns of concentric circles, and wherein the distance between the pellets is between 3mm and 3.5mm.

7. The tactile stimulation device according to claim 1, wherein the pellets comprise metal spheres, and wherein the metal spheres comprise one or more of steel, steel alloy, aluminum, aluminum alloy, and brass.

8. The tactile stimulation device according to claim 7, wherein the diameter of the metal spheres is between 1.2mm and 2.5mm.

9. The tactile stimulation device according to claim 1, wherein all of the pellets have the same diameter and are distributed in a regular pattern.

10. The tactile stimulation device according to claim 1, wherein the pellets have varied diameters, and they are arranged in concentric circular patterns, with each concentric circle corresponding to the pellets of a specific diameter.

11. The tactile stimulation device according to claim 1, wherein the pellets comprise spheres of a mass ranging from 0.5g to 3g.

12. The tactile stimulation device according to claim 1, wherein the elastomer body comprises two different elastomeric materials, wherein each of the elastomeric material occupies a different region of the geometry of the elastomer body.

13. The tactile stimulation device according to claim 1, wherein the pellets are arranged in concentric circles in view along a normal direction to the membrane surface, and wherein the diameter of the pellets in the inner circle is A, the diameter of the pellets in the next circle moving radially outward is B, the diameter of the pellets in the further next circle moving radially outward is C, and the diameter of the pellets in the outermost circular arrangement is D, wherein A>OB and D>OB.

14. A device for tactile stimulation, comprising: a tactile stimulation body (TSB) implemented by using the tactile stimulation device of anyone of claims 1-13; a tactile stimulation applicator coupled with the TSB; at least one strap; and and an electronic control box connected to the tactile stimulation applicator through the strap and comprising a microphone, wherein the electronic control box is configured to convert audio signals which are formed from received sound by the microphone to a series of tactile stimulation signals, each of the series of the tactile stimulation signals corresponds to a specific phoneme, wherein the electronic control box is further configured to transmit the tactile stimulation signals to the tactile stimulation applicator via the strap, such that the tactile stimulation applicator enables to trigger the TSB.

15. The device for tactile stimulation according to claim 14, wherein when a tactile stimulation signal is fed to a voice-coil actuator (VCA) of the TSB by the tactile stimulation applicator, the elastomer body is excited by the VCA of the tactile stimulation applicator, thereby producing vibration nodes of the pellets.