Silent communication mask with a movable acoustic retention element

Abstract

The invention relates to a silent communication face mask (1) intended to be placed on the head of a user (5), comprising: a shell (2) configured to cover the mouth and nose of the user (5), said shell (2) having at least one exhalation vent (14), at least one microphone (3) carried by the shell (2) and arranged so as to capture and transmit the user's speech (5), an acoustic absorption device (4) extending within the shell (2), the mask (1) having at least one first movable element (20) configured to adopt an open configuration of the exhalation vent (14) under the effect of the pressure of air exhaled by the user (5) and to adopt a closed configuration of the exhalation vent (14) in the absence of exhaled air, thus rendering the user's speech (5) unintelligible. Figure for the abstract: Fig. 1

Description

Title of the invention: Silent communication mask comprising a mobile acoustic retention element Technical field

[0001] The present invention relates to the field of communication masks.

[0002] In particular, it proposes a silent communication mask allowing a user of the mask to talk with someone via the mask, without being heard by people geographically close. STATE OF THE ART

[0003] In recent years, nomadic work, or teleworking, an activity which consists of working from a location other than the dedicated place of employment, has grown considerably. This development has been stimulated in particular by technological advances, particularly in the field of mobile communication devices such as smartphones, tablets or laptops, as well as by the rise of reliable and fast means of communication such as broadband internet and online collaboration tools.

[0004] The emergence of the possibility of working from anywhere poses certain problems, especially when the chosen workplace is a public place or shared with other people located nearby, for example a train, a cafe or a library.

[0005] Indeed, workers may have to participate in videoconference meetings, during which they will have to discuss confidential matters with colleagues or clients remotely. This situation, in addition to being problematic in terms of confidentiality for the worker, may also be uncomfortable for those present near the worker.

[0006] In order to ensure comfortable communication for mobile workers, even in difficult or noisy environments, communication masks have been developed. Such devices are traditionally composed of a sound-capturing device such as a microphone, a shell covering the user's nose and mouth, a device for attaching to the user's head, and inhaling and exhaling vents.

[0007] To solve this problem, the company SKYTED has developed a so-called silent communication mask, incorporating an acoustic absorbing device.

[0008] More specifically, the proposed mask incorporates a surface trim element which comes from the invention described in patent FR3065570 and which ensures improved acoustic absorption.

[0009] This invention makes it possible to imagine surface linings absorbing waves acoustics adapting to very specific sound environments to be treated. In addition, the effectiveness of these gaskets depends only on their shape, and not on the materials used. The materials chosen are therefore free, depending on environmental constraints, such as temperature, mass limitations, mechanical resistance, etc. Finally, this free choice of shaping materials also allows great freedom of manufacturing methods, which can be additive manufacturing or injection molding.

[0010] This invention therefore makes it possible to effectively treat acoustic waves in very harsh environments, for example on aircraft nacelles with metallic materials and manufacturing methods by additive manufacturing. It also makes it possible to very effectively and targetedly treat noise from industrial equipment, noise from transport, such as railways, automobiles, aircraft, boats. Finally, this freedom of materials (rigid / soft) and the possibility of manufacturing by injection allows targeted and low-cost applications in the domestic environment: household appliances (vacuum cleaners, heating or ventilation systems, tools, etc.).

[0011] It is desired to further improve the confidentiality provided by the communication mask developed with this acoustic absorption material.

[0012] Furthermore, communication masks have the constraint of having to be of limited size, in order to be compatible with nomadic use and allow freedom of movement for the user. The need for compactness of the mask limits the usable treatment surface for acoustic absorption, and therefore constitutes a parameter limiting the relative efficiency of acoustic absorption. Statement of the invention

[0013] A general aim of the invention is to propose a communication mask allowing further improved confidentiality.

[0014] Communication masks have breathing vents that can allow unabsorbed acoustic waves to "radiate" and escape from the mask.

[0015] According to one aspect, the invention proposes a mask with at least one first movable element capable of adopting a configuration for opening an exhalation vent under the effect of pushing air exhaled by the user and a configuration for closing said vent in the absence of exhaled air, thus making the user's words unintelligible.

[0016] Thus, the confidentiality of the mask is reinforced with respect to people located near the user.

[0017] This solution also has the advantage of not impacting the compactness of the mask.

[0018] To this end, the invention proposes a silent communication face mask intended to be placed on a user's head, comprising: - a shell configured to cover the user's mouth and nose, said shell comprising at least one exhalation vent, - at least one microphone carried by the shell and arranged so as to pick up and transmit the user's words, and - an acoustic absorbing device extending into the hull.

[0019] Furthermore, the mask comprises at least one first mobile element configured to adopt a configuration of opening the exhalation vent under a pushing effect of air exhaled by the user and to adopt a configuration of closing the exhalation vent in the absence of exhaled air, thus making the user's words unintelligible.

[0020] Advantageously, the first mobile element is configured to close elastically in the absence of expelled air, with a return duration in the closing configuration such that the first mobile element is back in the closing configuration of the exhalation vent at the start of each pronunciation of a syllable in a group of words.

[0021] Preferably, the first mobile element is configured to move into the closing configuration from the opening configuration upon stopping the exhaled air pushing force in a duration of less than 250 ms.

[0022] Advantageously, the first movable element comprises a first edge fixed to the shell or to an edge of the exhalation vent and a second free opposite edge.

[0023] Advantageously, the first mobile element is intended to be located at a distance from the mouth of the user wearing the mask of between 4 and 26 centimeters.

[0024] In one embodiment, the first movable element is a membrane or comprises a bundle of flexible fibers.

[0025] In one embodiment, the mask comprises a second movable element arranged opposite the first movable element, the first and second movable elements extending in a plane for closing the exhalation vent when said first and second movable elements are in the closed configuration.

[0026] In another embodiment, the first movable element comprises an impeller.

[0027] In one embodiment, the shell comprises an inspiration vent, the mask comprising a third and optionally a fourth mobile elements capable of adopting an opening configuration of the inspiration vent reached under a thrust effect of incoming air inspired by the user and a closing configuration of the inspiration vent when the user does not inspire air, said third and fourth mobile elements being configured to close elastically in the absence of inspired air.

[0028] In such an embodiment, the mask comprises a first stop element blocking the opening of the exhalation vent under the effect of the thrust of the air inspired by the user, and comprising a second stop element blocking the opening of the inspiration vent under the effect of the thrust of the air exhaled by the user. DESCRIPTION OF FIGURES

[0029] Other characteristics, aims and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which:

[0030] [Fig. 1] illustrates a communication mask according to an embodiment of the invention worn by a user;

[0031] [Fig.2] schematically illustrates the communication mask of [Fig.l] in top view;

[0032] [Fig.3A] illustrates an example of a first and a second movable element according to a first embodiment, in front view, in the closed configuration;

[0033] [Fig.3B] illustrates the first and second movable elements according to the first embodiment, in top view, in the opening configuration;

[0034] [Fig.3C] illustrates an example of a first and a second movable element according to a second embodiment, in top view, in the opening configuration;

[0035] [Fig.4] illustrates an example of a first and a second movable element according to a third embodiment, in front view;

[0036] [Fig.5A] illustrates an example of a first and a second movable element according to a fourth embodiment, in front view, in the closed configuration;

[0037] [Fig.5B] illustrates an example of a first and a second movable element according to the fourth embodiment, in top view, in the opening configuration and in the closing configuration;

[0038] [Fig.5C] illustrates an example of a third and a fourth movable elements according to an embodiment, in top view, in closed configuration and in open configuration;

[0039] [Fig.6A] schematically illustrates an example of a sonogram of the 1st formant of the syllable “no” and the effects of the mask according to the invention on intelligibility for a person not wearing the mask;

[0040] [Fig.6B] schematically illustrates an example of a sonogram of the 1st formant of the syllable “bab” and the effects of the mask according to the invention on intelligibility for a person not wearing the mask;

[0041] [Fig.6C] schematically illustrates an example of a sonogram of the 1st formant of the syllable “gag” and the effects of the mask according to the invention on intelligibility for a person not wearing the mask;

[0042] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION OF THE INVENTION Example of general mask structure:

[0043] The communication mask 1 illustrated in Figures 1 and 2 comprises a shell 2, at least one microphone 3 and an acoustic absorbing device 4. Fasteners 6 make it possible to hold the mask in position on the head of a user 5.

[0044] The shell 2 is configured to cover the mouth and preferably the nose of the user 5. An inner surface 8 of the shell 2 defines a cavity 12 surrounding the mouth and preferably the nose of the user 5 when the mask 1 is worn by the latter, for example in particular by means of a mouthpiece 13.

[0045] The microphone 3 is arranged in the shell 2 and configured to capture the acoustic waves emitted by the user 5 to transmit them remotely, for example to a mobile telephone via communication electronics.

[0046] The sound-absorbing device 4 is arranged on a portion of the inner surface 8 of the shell 2. More precisely, the sound-absorbing device 4 forms an inner lining of the cavity 12. It is thus arranged to be in the path of the sound waves emitted by the user 5 wearing the mask 1 while speaking and is for example constituted by a surface trim element as described in the document FR3065570. The sound-absorbing device 4 thus makes it possible to at least partially acoustically absorb the sound waves emitted by the user 5 while not being sealed against the air exhaled by the user 5, which can escape from the cavity 12 by passing through said sound-absorbing device 4. Vent(s) and moving elements:

[0047] The shell 2 comprises one or more exhalation vents 14, for example arranged on lateral surfaces 10, 11 of the shell 2, other locations of the shell 2 being of course conceivable such as for example an external surface 9 of the shell 2 opposite the internal surface 8.

[0048] An exhalation vent 14 consists for example of an opening in the shell 2 opening onto the outside of the mask 1 on the one hand and communicating with the cavity 12 via the acoustic absorber device 4 on the other hand, so that the air exhaled by the user 5 can escape from the mask 1 after having escaped from the cavity 12 by passing through the acoustic absorber device 4. For example and as shown in the figures, the exhalation vent 14 can be of a rectangular shape with a length of between 1 and 3 centimeters, and a width of between 2 and 4 millimeters.

[0049] Furthermore, the mask 1 comprises at its vent(s) 14 at least one mobile element 20 configured to chop up the sound likely to come out through the vent 14 and make the words escaping from the mask 1 at least partially unintelligible for a person located near the user 5 wearing the mask 1.

[0050] More precisely, the mobile element 20 is configured to adopt a configuration of opening the exhalation vent 14 under a pushing effect of the air exhaled by the user 5, and to adopt a configuration of closing the exhalation vent 14 in the absence of exhaled air.

[0051] Alternatively, the movable element 20 is arranged in the shell 2 between the cavity 12 and the exhalation vent 14, and extends in a plane for closing the exhalation vent 14 in the closed configuration, as shown for example in FIGS. 1 and 2.

[0052] In one embodiment, the movable element 20 is deformable in flexion and comprises for example a flexible membrane or a bundle of flexible fibers. One of its edges 20a is attached to the edge of the exhalation vent 14 or to an inner wall of the shell 2; its other opposite edge 20b is free. In the unstressed configuration, the movable element 20 closes all or part of the exhalation vent 14 and therefore occupies the closed configuration; in addition, the movable element 20 deforms in flexion under the effect of the pressure of the air exhaled by the user 5 to allow said exhaled air to escape. Several mobile elements may also be provided to close the same vent, for example a first mobile element 20 and a second mobile element 23 formed by two membranes (as illustrated in FIGS. 3A, 3B and 3C for example) or two bundles of membranes (as illustrated in [Fig.4] for example) one opposite the other and each attached to an edge of the exhalation vent 14 or to an inner wall of the shell 2 located between the cavity 12 and the exhalation vent 14 in the plane of closure of the exhalation vent 14. An embodiment with two movable elements 20 and 23 is shown in Figures 3A (in closed configuration), 3B and 3C (in open configuration), in which the second movable element 23 comprises an edge 23a attached to the edge of the exhalation vent 14 opposite the edge carrying the edge 20a of the first movable element 20, and a second opposite edge 23b free.

[0053] Thus, when the user 5 speaks or is in the exhalation phase, the air exhaled by the user 5 causes a flexural movement of the movable element 20 (if applicable, the movable elements 20, 23), which opens the exhalation vent 14. The movable element 20 is then in the opening configuration of the exhalation vent 14, as is the second movable element 23 if applicable. Figures 3B and 3C illustrate the movable elements 20, 23 in two extreme flexural positions when they are stressed by the exhalation of the user 5.

[0054] Conversely, when the user 5 stops speaking, or is in the inspiration phase, the exhaled air is stopped, stopping the pushing force previously exerted on the mobile element(s) 20, 23. Consequently, the mobile element 20 resumes the closing configuration of the exhalation vent 14, as does the second mobile element 23 if applicable, as shown in [Fig.3A].

[0055] Typically, the mobile element 20, and where appropriate the second mobile element 23, is configured to return to the closed configuration from the open configuration in a duration of less than 250 milliseconds. This duration corresponds to the minimum non-audible pause time generally observed after a series of syllables making up a word or a group of words. In this way, the mobile element 20, and where appropriate the second mobile element 23, returns to the closed configuration from the open configuration sufficiently quickly so that at the start of each syllable pronounced by the user 5 during the pronunciation of a group of words, the mobile element 20, and where appropriate the second mobile element 23, is in the closed configuration.

[0056] Such a mobile element 20, 23 deformable in flexion (membrane, bundle of fibers, etc.) is made of an elastic material sufficiently flexible to be able to be pushed and bend under the effect of the pushing force of the air exhaled by the user 5 while speaking, and sufficiently rigid to return to the closed configuration otherwise. Thus, such a mobile element 20, 23 is for example made of rubber, silicone, or elastomer in general. Such a mobile element 20, 23 can thus be an elastic material characterized by a Young's modulus of between 500 and 2500 MPa. The thickness of such a mobile element 20, 23 can be between 0.4 and 1 millimeter, in order to be thin enough to move into the open configuration under the effect of the pushing force of the air exhaled by the user 5 while speaking.

[0057] It will further be noted that, when the user 5 speaks, the emitted acoustic waves propagate at a speed of approximately 340 meters per second. The air exhaled by the user 5 while speaking propagates at an initial speed of approximately 1.3 meters per second, the acoustic waves arrive at the first mobile element 20, and where appropriate also at the second mobile element 23, well before the exhaled air exerts a thrust force on said first mobile element 20, and where appropriate also at the second mobile element 23, this at the start of each syllable due to the sufficiently rapid return time to the closed configuration of the first mobile element 20 and where appropriate of the second mobile element 23.Thus, the acoustic waves emitted by the user 5 while speaking and arriving at the level of the mobile element 20 (after passage of the acoustic absorbing device 4) before the exhaled air are reflected by the first mobile element 20 in the closed configuration obstructing the exhalation vent 14, if applicable by the two mobile elements 20, 23. In this way, the acoustic waves are retained in the mask 1, which improves the overall acoustic attenuation of the mask 1. This improved acoustic attenuation is effective until the air exhaled by the user 5 comes into contact with the first mobile element 20 or with the two mobile elements 20, 23 if applicable, and thus exerts a pushing force on it / them. The mobile element 20, and the case . if necessary the second mobile element 23, then passes into the opening configuration and then lets escape on the one hand the exhaled air and on the other hand the acoustic waves arriving from this moment, this as long as the mobile element 20, and if necessary the second mobile element 23, is stressed by such a pushing force and has not returned to the closing configuration when said pushing force stops. In this way, each syllable spoken by the user 5 is rendered partially unintelligible. Indeed, the words or syllables that can be perceived in the absence of such a mobile element 20 are "chopped" so that a person near the user 5 will not be able to distinctly understand said words or syllables. This unintelligibility will be variable and more or less significant depending on the syllable pronounced, each syllable pronounced causing a more or less early expiration and of more or less long duration depending on the language.For example, the duration of a syllable in French is between 200 and 250 milliseconds, while the duration of a syllable in Chinese is between 200 and 400 milliseconds.

[0058] In French, the average duration of a vowel is approximately 100 to 200 milliseconds (ms) while the average duration of a consonant is approximately 30 to 100 milliseconds (ms).

[0059] If the first letter, vowel or consonant, is pronounced in part or entirely before the movable element 20 is pushed by the air flow, the syllable will potentially be unintelligible.

[0060] In order to optimize the unintelligibility effects, it is necessary to respect distance conditions between the mouth and the exhalation vent 14.

[0061] Indeed, the distance between the mouth and the first mobile element 20, or the two mobile elements 20, 23 if applicable, must make it possible to cover the shortest duration provided by a vowel or a consonant emitted in a conversation, which is of the order of 30 milliseconds. Due to the speed of the exhaled air equal to approximately 1.3 m / s, the mobile element 20, and if applicable the second mobile element 23, must be located at a minimum distance of 4 cm from the mouth, so that the exhalation of air is completed at the moment when the thrust of the exhaled air begins to be exerted on the first mobile element 20.

[0062] Similarly, a maximum distance between the movable element 20 and the mouth can be determined in order to prevent the first movable element 20, and where appropriate the second movable element 23, from being in the open configuration at the end of a syllable and remaining open until the following syllable. Nevertheless, this maximum distance is relatively large, and is generally incompatible with the need for compactness of the mask. For example, for the pronunciation of the syllable “le” or the syllable “no”, the respective emission durations of which are 200 milliseconds, the maximum distance is 26 cm.

[0063] In order to illustrate the effects on the intelligibility of sounds escaping from mask 1, we recall below some elements on the physics of speech.

[0064] In particular, vowels are the longest sounds and are easily identifiable. When a sound is emitted from the glottis of user 5, harmonics appear and are filtered by the vocal tract of user 5. A frequency spectrum of this sound is then in the form of modulated harmonics called “formants”.

[0065] The presence of a vowel provides information on the presence of consonants before or after said vowel, by a modification of the trajectory of the formants during the transitions before and after the vowel.

[0066] Consonants can be occlusive, such as "b" or "g", in which case the passage of air is momentarily blocked by an occlusion of the vocal tract during their pronunciation.

[0067] Consonants can also be oral, such as "1", in which case the soft palate is raised (or lowered in the case of so-called restrictive consonants) and air passes through the mouth.

[0068] Finally, the consonants can be nasal, such as "n", in which case the vocal tract is momentarily occluded by a lowering of the soft palate while the nasal cavities allow a continuous flow of air to pass through.

[0069] Although oral and nasal consonants involve a more or less restricted expiration, the pronunciation of such a consonant may be totally or partially unintelligible depending on its duration. For example, and as illustrated in [Fig.6A] which schematically represents the 1st formant from a sonogram of the vowel “no”, the duration of the consonant “n”, which extends between the instants t0 and tl, is greater than the opening time of the exhalation vent 14 (which corresponds to the time taken by the exhaled air from the start of pronunciation of the syllable to exert a pushing force on the mobile element 20 or the mobile elements 20, 23 as the case may be, and therefore open the exhalation vent 14, the opening time of the exhalation vent 14 being represented by the window F), such that this consonant is partially retained by a person near the user 5 wearing the mask 1.

[0070] Conversely, as illustrated in [Fig.6B] which represents the 1st formant from a sonogram of the vowel “bab”, the duration of the consonant “b” (between times t4 and t5) is slightly less than the opening time of the expiration vent 14 illustrated by the window F (t4 and t5 being outside the window F), so that the letter “b” is totally retained in the mask 1, as is the beginning of the vowel “a”, which is pronounced between t5 and t6, and part of which is located outside the window F.

[0071] In the same way, [Fig.6C] which represents the 1st formant from a sonogram of the vowel “gag”, the duration of the consonant “g” (between times t8 and t9) is slightly greater than the opening time of the expiration vent 14 illustrated by the window F (t9 being inside window F unlike t8), so that the letter “g” is partially retained in mask 1.

[0072] Thus, depending on the syllables spoken, the words are retained more or less by the at least one mobile element 20, so that the unintelligibility for a person close to the user 5 is increased.

[0073] In one embodiment, the shell 2 further comprises an inspiration vent 16 similar to the expiration vent 14. The inspiration vent 16 may be provided on one of the lateral surfaces 10, 11, for example on the second lateral surface 11, or in other words on the lateral surface opposite the lateral surface on which the expiration vent 14 is provided. Alternatively, the inspiration vent 16 may be provided anywhere on the outer surface 9 of the shell 2. The inspiration vent 16 consists for example of an opening in the shell 2, so that the user 5 can inspire air from outside the mask 1, this inspired air entering the mask through the inspiration vent 16. For example, the inspiration vent 16 may be of a rectangular shape of length and width similar to those of the expiration vent 14.Alternatively, the mask 1 may, like the exhalation vent 14, comprise a plurality of inspiration vents 16. Preferably, the total surface area of ​​the inspiration vent(s) 16 is identical to the total surface area of ​​the exhalation vent(s) 14.

[0074] In an alternative embodiment, the exhalation vent 14 and the inspiration vent 16 are merged.

[0075] In an embodiment in which the exhalation vent 14 and the inspiration vent 16 are not merged and advantageously in this case, the mask 1 comprises, in a manner analogous to the exhalation vent 14, at least one third movable element 25 similar to the first movable element 20, and optionally a fourth movable element 26 similar to the second movable element 23, the third and fourth movable elements 25, 26 being at opposite edges of the inspiration vent 16, or alternatively on interior walls of the mask 1 opposite each other and located between the cavity 12 and the inspiration vent 16 (as illustrated in [Fig. 2], but not in [Fig. 1] for reasons of clarity).In such an embodiment, the movable elements 20, 23 on the exhalation vent 14 side may comprise a first stop element 27 configured to block the opening of said movable elements 20, 23 from the obturation plane towards the cavity 12, i.e. to block the opening of said movable elements 20, 23 during the inhalation of the user 5. Similarly, the movable elements 25, 26 on the inspiration vent 16 side may comprise a second stop element 28 configured to block the opening of said movable elements 25, 26 from the obturation plane towards the inspiration vent 16, i.e. to block the opening of said movable elements 25, 26 during the expiration of . the user 5. The stop elements 27, 28 may be similar, and for example comprise protrusions 30 extending from an edge of the corresponding vent 14, 16 or from an interior wall of the mask 1.

[0076] In an alternative embodiment, the first movable element 20 is a paddle wheel. In such a case, the first movable element 20 is arranged in a housing made in the mask between the cavity 12 and the exhalation vent 14, so that the paddle wheel, which comprises an axis of rotation passing through its center, is rotated under the effect of the thrust of the air exhaled by the user 5. Thus, the first movable element 20 is arranged so that the axis of rotation of the paddle wheel is perpendicular to an axis of the housing connecting an upstream portion of the housing and a downstream portion of the housing, the downstream portion communicating with the exhalation vent 14 and the upstream portion communicating with the cavity 12 via the sound-absorbing device 4.

[0077] The diameter of the impeller is chosen so that when stationary, almost no air passes between the upstream and downstream sides of the impeller, i.e. a diameter of at least 95% of the minimum distance separating two opposite walls of the housing parallel to the axis of rotation of the impeller. In other words, the diameter of the impeller is chosen so that when stationary, no air passes between the blade tips and an opposite wall of the housing.

[0078] The closing configuration of the first mobile element 20 therefore corresponds to the stopping of the blade wheel, that is to say in a position of the blades closing the passage of air between the upstream and downstream of the blade wheel, in other words between the blade tips and a wall of the housing opposite.

[0079] When the user speaks or exhales air, the air exhaled by the user exerts a thrust force on the blades of the paddle wheel, setting the first movable element 20 in rotational motion about the axis of rotation. Thus, the air lodged between the blades can pass from an upstream portion of the housing to a downstream portion of the housing, and escape from the mask 1 by joining the exhalation vent 14. The opening configuration of the exhalation vent 14 of the first movable element 20 therefore corresponds to the rotation of the paddle wheel.

Claims

Claims

1. Silent communication face mask (1) intended to be placed on a head of a user (5), comprising: - a shell (2) configured to cover the mouth and nose of the user (5), said shell (2) comprising at least one exhalation vent (14), - at least one microphone (3) carried by the shell (2) and arranged so as to pick up and transmit the words of the user (5), - an acoustic absorbing device (4) extending in the shell (2), characterized in that the mask (1) comprises at least one first movable element (20) configured to adopt a configuration of opening the exhalation vent (14) under a pushing effect of air exhaled by the user (5) and to adopt a configuration of closing the exhalation vent (14) in the absence of exhaled air, thus making words of the user (5) unintelligible.

2. Mask (1) according to claim 1, in which the first movable element (20) is configured to close elastically in the absence of expelled air, with a return duration in the closing configuration such that the first movable element (20) is back in the closing configuration of the exhalation vent (14) at each start of pronunciation of a syllable in a group of words.

3. Mask (1) according to claim 1 or 2, in which the first movable element (20) is configured to pass into the closing configuration from the opening configuration upon stopping the force of pushing the exhaled air in a duration of less than 250 ms.

4. Mask (1) according to one of claims 1 to 3, in which the first movable element (20) comprises a first edge (20a) fixed to the shell (2) or to an edge of the exhalation vent (14) and a second free opposite edge (20b).

5. Mask (1) according to one of claims 1 to 4, in which the first movable element (20) is intended to be located at a distance from the mouth of the user (5) wearing the mask of between 4 and 26 centimeters.

6. Mask (1) according to one of claims 1 to 5, in which the first movable element (20) is a membrane or comprises a bundle of soft fibers.

7. Mask (1) according to one of claims 1 to 6, comprising a second movable element (23) arranged opposite the first movable element (20), the first and second movable elements (20 and 23) extending in a plane for closing the exhalation vent (14) when said first and second movable elements (20 and 23) are in the closed configuration.

8. Mask (1) according to claim 1 to 3, wherein the first movable element (20) comprises a paddle wheel.

9. Mask (1) according to one of claims 1 to 8, in which the shell (2) comprises an inspiration vent (16), the mask (1) comprising a third and optionally a fourth movable elements (25 and 26) capable of adopting an opening configuration of the inspiration vent (16) reached under a thrust effect of incoming air inspired by the user (5) and a closing configuration of the inspiration vent (16) when the user (5) does not inspire air, said third and fourth movable elements (25 and 26) being configured to close elastically in the absence of inspired air.

10. Mask (1) according to claim 9 in combination with claim 7, comprising a first stop element (27) blocking the opening of the exhalation vent (14) under the effect of the thrust of the air inspired by the user (5), and comprising a second stop element (28) blocking the opening of the inhalation vent (16) under the effect of the thrust of the air expired by the user (5).

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