Headrest equipped with a system for two-way sound transmission via bone conduction

Abstract

The present invention relates to a headrest (10) equipped with a two-way bone conduction sound transmission system (1), which comprises one or more bone conduction speakers (5) and one or more bone conduction microphones (7) mounted on one and the same printed circuit board (3). Additional components of the two-way bone conduction sound transmission system (1), such as a control unit (13), contact and / or proximity sensors (9, 11), and an antenna for communication with external electronic devices, can be mounted on the same printed circuit board (3). Thanks to this solution, the assembly of the components of the two-way bone conduction sound transmission system (1) becomes easier, and the subsequent assembly of the two-way sound transmission system inside the headrest (10) becomes simpler, faster, and less prone to human error, thus reducing manufacturing costs while improving the quality of the final product.

Description

[Technical Field]

[0001] The present invention relates to a headrest equipped with a system for two-way sound transmission by bone conduction.

[0002] The present invention is more particularly applicable to the manufacture of head restraints for vehicle seats, and even more particularly to the manufacture of head restraints for automobile seats. [Background technology]

[0003]

[0003] Bone conduction is a well-known phenomenon by which sound is transmitted to the inner ear through the bones of the skull (instead of through the air).

[0004]

[0004] Sound transmission by bone conduction has several advantages, including: - Does not block out external sounds, allowing users to remain aware of noises in their surrounding environment; - Maintaining sound clarity in noisy environments; - Ensures a high level of privacy as sound is not dispersed into the surrounding environment.

[0005] These advantages are particularly appreciable in enclosed environments of limited size that can accommodate only a few people, such as the cockpit of a vehicle, and more particularly an automobile.

[0006]

[0006] For this reason, headrests for vehicle seats equipped with bone conduction two-way sound transmission systems have been developed in the past few years.

[0007]

[0007] In the case of a driver's headrest, it is clear that the possibility of listening to music or having a telephone conversation without being interrupted by the perception of noise in the surrounding environment is extremely advantageous, for example in order to be able to perceive the presence of an approaching emergency vehicle or to quickly avoid a potentially dangerous situation.

[0008]

[0008] More generally, headrests equipped with bone conduction sound transmission systems allow different occupants of the same vehicle to listen to different music without disturbing other occupants, or to carry telephone conversations with a degree of privacy.

[0009]

[0009] For example, document JP 2018-125829 discloses a headrest for a vehicle seat having a section that protrudes towards the occupant's rear head when the occupant is in a normal sitting position, and in this document a seat suitable for accommodating a bone conduction loudspeaker is provided.

[0010]

[0010] A headrest having a similar structure is also described in Japanese Patent Application Laid-Open No. 2007-125071.

[0011]

[0011] JP 2005-118248 A relates to a headrest for a vehicle seat including a bone conduction microphone and a bone conduction loudspeaker. One of the microphone and the speaker is attached to a part of the headrest in contact with the cervical vertebrae of a person sitting in the seat, and the other is attached to a part of the headrest in contact with the person's skull. The headrest is installed so that it can be oriented toward the person sitting in the seat so that the bone conduction microphone and the bone conduction speaker can properly contact their respective structural parts.

[0012]

[0012] A headrest having a similar structure is also described in JP 2004-083004, but only a part of the headrest including a bone conduction microphone and a bone conduction speaker is pivotally mounted toward the skull of the person occupying the seat.

[0013]

[0013] Document CN110949219 discloses a structure for a headrest for a vehicle seat having a bone conduction sound transmission device and a conventional sound transmission device, the headrest further including a pressure sensor for detecting contact between the skull of a person sitting in the seat and the headrest, and a control unit for selectively activating / deactivating the bone conduction sound transmission device and the conventional sound transmission device.

[0014]

[0014] Document KR10-1500217 discloses a structure for a headrest for a vehicle seat, including a first portion in which a bone conduction sound transmission device is received and a second portion that is mechanically deformable, the headrest further including a proximity sensor for detecting the position of the skull of a person seated in the seat, and means for deforming the second portion of the headrest until it comes into contact with the skull of the person.

[0015]

[0015] However, the solutions described in the aforementioned documents, and more generally those available in the state of the art, are not without drawbacks.

[0016] In particular, these solutions are either crude and not very efficient, or are extremely complicated.

[0017]

[0017] In the case of simple but not very efficient headrest structures, two-way transmission of sound by bone conduction may be of poor quality or may be interrupted, or excessive contact with the skull of the person sitting in the seat may make use of the headrest extremely uncomfortable, if not annoying.

[0018]

[0018] In the case of sophisticated but complex headrest structures, this complexity can lead to a significant increase in manufacturing time and costs. Furthermore, in the case of a two-way bone conduction sound transmission system that includes a large number of parts to achieve good performance, it is necessary to consider not only the increased assembly time of the headrest but also the increased risk of errors when positioning and connecting the various parts to each other.

[0019]

[0019] In view of all the above, the main object of the present invention is to provide a headrest equipped with a bone conduction two-way sound transmission system that overcomes the limitations of the prior art and combines a simple and reliable structure with high performance.

[0020] Another object of the present invention is to provide a headrest equipped with a bone conduction two-way sound transmission system that ensures high comfort for the user while guaranteeing good quality sound transmission.

[0021]

[0021] These and other objects are achieved by a headrest as claimed in the accompanying claims. Summary of the Invention [Means for solving the problem]

[0022]

[0022] Thanks to the fact that one or more bone conduction loudspeakers and one or more bone conduction microphones are mounted on one and the same printed circuit board, the bone conduction two-way sound transmission system for a headrest according to the present invention has a simple and compact structure.

[0023]

[0023] Advantageously, the assembly of the various components of the bone conduction two-way sound transmission system, as well as any other additional components present on the printed circuit board, can be carried out in a separate step different from the assembly of the headrest, which can be carried out under favorable conditions to achieve high reliability and precision. As a result, in the assembly of the headrest, only a single component (i.e., the printed circuit board) needs to be installed in the headrest, which dramatically reduces the risk of human error in terms of correct positioning.

[0024]

[0024] Furthermore, by being able to arrange and connect the various components of the bone conduction two-way sound transmission system, as well as any other additional components present on the printed circuit board, in separate steps, the overall time and cost for manufacturing the headrest can be optimized and minimized.

[0025]

[0025] Furthermore, by assembling the various components of the bone conduction two-way sound transmission system on the same printed circuit board, the overall number of electronic components and connections can be reduced, leading to greater reliability and reduced costs.

[0026]

[0026] In addition, such a compact structure of the sound transmission system according to the present invention allows the overall size of the system itself to be minimized, making it possible to incorporate the sound transmission system into the headrest body in a simpler manner.

[0027] In addition to the advantages mentioned above regarding the manufacturing process, locating the bone conduction loudspeaker and the bone conduction microphone on the same printed circuit board also entails several advantages regarding the bone conduction two-way sound transmission system.

[0028]

[0028] More specifically, both the bone conduction loudspeaker and the bone conduction microphone are simultaneously optimally positioned with respect to the user's head and headrest.

[0029] In a preferred embodiment of the invention, the printed circuit board carrying the bone conduction loudspeaker and bone conduction microphone is located in the portion of the headrest that is closest to the back of the user's head during use.

[0030]

[0030] At the back of the head, there is less human tissue through which signals must travel to reach the user's inner ear, thereby improving the quality of sound transmission during both speaking and listening.

[0031]

[0031] Additionally, users generally have less hair at the back of their head than at the upper region of their head (top), and since the presence of hair between the user's skull and the bone conduction loudspeaker and microphone can cause undesirable noise due to vibrations caused by friction between the hair and the headrest, placing both the bone conduction loudspeaker and the bone conduction microphone close to the back of the user's head improves the sound-to-noise ratio and therefore improves the quality of communication.

[0032] According to the present invention, the bone conduction loudspeaker and the bone conduction microphone are mounted at different locations on the same printed circuit board.

[0033]

[0033] This allows a layer of sound-absorbing material to be placed between the bone conduction loudspeaker and the bone conduction microphone, thereby avoiding interference between the input signal (inward communication) and the output signal (outward communication).

[0034] Advantageously, the bone conduction loudspeaker and the bone conduction microphone are mounted on the same printed circuit board in such a way that the input and output signals travel through different skull bones, which helps to avoid interference and disturbances between inbound and outbound communications.

[0035]

[0035] The printed circuit board may be a rigid printed circuit board, but in a preferred embodiment of the present invention it is a flexible printed circuit board.

[0036]

[0036] The flexibility of the printed circuit board itself can inherently damp undesired vibrations, thereby suppressing potential interference between the bone conduction loudspeaker and the microphone, and by using a flexible printed circuit board, the risk of interference and disturbance between the input and output signals can be avoided.

[0037]

[0037] Incidentally, the selection of a flexible printed circuit board is particularly advantageous at high sound power levels due to its ability to reduce undesirable vibrational feel.

[0038] The damping properties of the flexible printed circuit board can also reduce the mechanical stress on the electronic components mounted thereon.

[0039]

[0039] Additionally, the use of a flexible printed circuit board optimizes contact between the bone conduction loudspeaker and microphone and the user's head, and allows the bone conduction sound transmission system of the present invention to fit headrests of any shape and design.

[0040]

[0040] The use of flexible printed circuit boards can also improve the thermal management of the sound transmission system, as it dissipates heat in a better way.

[0041]

[0041] In a preferred embodiment of the present invention, the printed circuit board carrying the bone conduction two-way sound transmission system is mounted on a portion of the headrest that is separate from the headrest body and is movable relative to the body.

[0042]

[0042] According to this embodiment, the separate headrest portion can be brought from a rest position spaced apart from the user's skull to an operative position in contact with the user's skull.

[0043]

[0043] This possibility improves the comfort of the user, since if the user is a driver of a vehicle, he / she can maintain the most comfortable driving position for himself / herself without having to worry about keeping his / her head in contact with the headrest.

[0044]

[0044] In this regard, it should be noted that experimental studies have shown that the efficiency of sound transmission is greatest when in contact with the back of the user's skull (mainly for the reasons already explained above).

[0045]

[0045] In the case of a conventional headrest, the part of the skull that first comes into contact with the headrest is the top of the head (unless the headrest is oriented in a completely uncomfortable way for the user), whereas by installing a bone conduction two-way sound transmission system in a movable and adjustable headrest part, said part can be positioned to come into contact with the back of the user's skull.

[0046]

[0046] In this embodiment, the user can manually move the movable headrest portion, but the headrest portion is preferably provided with a proximity sensor and / or contact sensor together with an actuator that drives the displacement of said movable portion, and a control unit that sends a command signal to said actuator in accordance with the data detected by said proximity sensor and / or contact sensor.

[0047]

[0047] Advantageously, the sensor, control unit, and the connections between the sensor and the control unit, and the connections between the control unit and the actuator, can be provided on the same printed circuit board that holds the bone conduction two-way sound transmission system.

[0048]

[0048] Although the present invention finds particular application in the field of motor vehicles ("automobiles"), it will be clear that headrests according to the invention are equally applicable to headrests for seats in other types of vehicles (public transport, trains, aircraft, etc.), and more generally to all other kinds and types of seats.

[0049] Further features and advantages of the present invention will become more apparent from the detailed description of preferred embodiments given as non-limiting examples with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0050] [Figure 1a] 1 is a schematic view of a headrest according to the present invention shown in a first operating position. [Figure 1b]

[0051] 2 is a schematic view of a headrest according to the present invention shown in a second operating position; [Figure 1c]

[0052] 2 is a schematic view of a headrest according to the present invention shown in a third operating position; [Figure 2]

[0053] FIG. 1 is a schematic diagram of the bone conduction two-way sound transmission system of FIGS. 1a to 1c. DETAILED DESCRIPTION OF THE INVENTION

[0051]

[0054] In the following description of a preferred embodiment of the present invention, reference is made to its application to a headrest for an automotive vehicle seat.

[0052]

[0055] It should be understood that this application should not be understood in a limiting sense, and that several other applications can be envisaged for headrests for other types of seats.

[0053]

[0056] Figures 1a to 1c show diagrammatically a headrest 10 according to the invention.

[0054]

[0057] In a manner known per se, said headrest 10 comprises a body 12 mounted on a single central body or on two rods 14 and connected via said central body / two rods to the backrest of the corresponding seat.

[0055]

[0058] The body 12 of the headrest 10 preferably has an anatomical shape and is mounted on a single central body or rod 14 in an adjustably manner so that its position can be adapted to the morphology of the user.

[0056]

[0059] More particularly, the body 12 of the headrest 10 can be adjustable in height and / or orientation about a horizontal axis parallel to the seat backrest. For reasons that will become apparent hereinafter, it is preferred that the body be adjustable in orientation at least about said horizontal axis parallel to the seat backrest.

[0057]

[0060] According to the present invention, the headrest 10 is equipped with a bone conduction two-way sound transmission system, which will be described in more detail below.

[0058]

[0061] In the preferred embodiment of the present invention described and illustrated herein, the bone conduction two-way sound transmission system is separate from the main body 12 of the headrest and is installed in a headrest portion 16 connected to the main body so as to be movable relative to the main body.

[0059]

[0062] The headrest portion 16 holding the bone conduction two-way sound transmission system is preferably positioned at the bottom of the headrest portion body 12 so that it can contact the back of the user's skull rather than the top of the user's head.

[0060]

[0063] In fact, experimental testing has shown that a bone conduction two-way sound transmission system is optimal when contact occurs at the back of the head.

[0061]

[0064] In a particularly simple embodiment of the invention, the headrest portion 16 may be manually moved by the user so that the headrest portion 16 contacts his / her skull.

[0062]

[0065] However, in a preferred embodiment of the invention, movement of the headrest portion 16 is obtained by a suitably controlled actuator capable of obtaining translational and / or rotational movement of the headrest portion relative to the body of the headrest itself.

[0063]

[0066] Thanks to these actuators (the operation of which is described in more detail below), the headrest portion 16 holding the bone conduction two-way sound transmission system can be selectively brought from a rest position away from the user's skull (see Figure 1a) to an operating position in contact with the back of the user's skull (see Figures 1b and 1c).

[0064]

[0067] In this way, the headrest portion 16 does not interfere with the user's comfort when the bone conduction two-way sound transmission system is not in use, but ensures proper contact with the user's skull when the bone conduction two-way sound transmission system is in use.

[0065]

[0068] The headrest portion 16 is preferably made from a sponge material, and even more preferably from a shape memory foam, in this way, when said headrest portion contacts the user's skull, it fits to the specific shape of the user's skull to increase the contact area with the skull itself and ensure optimal operation of the bone conduction device.

[0066]

[0069] In a particularly preferred embodiment of the invention, the front part of the headrest portion 16, which faces the user's skull and is intended to be in contact with it, is made from a sponge material, preferably from a shape memory foam, while the rear part of the headrest portion 16, which faces away from the user's skull, is made from a sound-absorbing material. Thanks to this precaution, no sound is transmitted to the surrounding environment, even when the bone conduction two-way sound transmission system is used at very high volumes.

[0067]

[0070] A bone conduction two-way sound transmission system 1 for a headrest 10 according to the present invention is shown diagrammatically in FIG.

[0068]

[0071] The two-way sound transmission system 1 includes at least one bone conduction loudspeaker 5 and at least one bone conduction microphone 7, and according to the present invention, the at least one bone conduction loudspeaker 5 and the at least one bone conduction microphone 7 are located on one and the same printed circuit board 3.

[0069]

[0072] The conduction loudspeaker 5 and the bone conduction microphone 7 are positioned at different locations on the printed circuit board 3 to avoid undesired interference and disturbances between the input and output signals.

[0070]

[0073] Preferably, a layer of sound absorbing material is placed between the conduction loudspeaker 5 and the bone conduction microphone 7 so that the risk of unwanted interference and disturbances between the input and output signals is further reduced.

[0071]

[0074] In view of known solutions, providing a single printed circuit board that holds both the bone conduction speaker and the bone conduction microphone allows for flexibility in designing the geometry and shape of the headrest, ease of installing the device in the seat headrest, reduced assembly time, and better quality in assembly (due to reduced human error).

[0072]

[0075] The printed circuit board 3 may be a rigid printed circuit board, but is preferably a flexible printed circuit board.

[0073]

[0076] Advantageously, by using a flexible printed circuit board, the configuration of the circuit board itself can be adapted to obtain optimal positioning of the bone conduction device in the headrest portion 16 .

[0074]

[0077] Additionally, flexible printed circuit boards damp unwanted vibrations due to the flexibility of the printed circuit board, helping to prevent interference and disturbances between input and output signals, and reducing mechanical stress on loudspeaker and microphone components.

[0075]

[0078] In any case, it cannot be ignored that the printed circuit board 3 is obtained by combining rigid and flexible sections.

[0076]

[0079] 2 shows a pair of bone conduction speakers 5 and bone conduction microphones 7 symmetrically arranged on a printed circuit board 3. However, this configuration should not be construed as limiting, and the bone conduction two-way sound transmission system 1 can include any desired number of bone conduction devices. Those skilled in the art will be able to identify the right compromise between the efficiency of the two-way sound transmission and the complexity of the system.

[0077]

[0080] On the side opposite to the side carrying the bone conduction devices 5, 7 (i.e., the side furthest from the user), the printed circuit board 3 can then advantageously be bonded to a layer of sound-absorbing material, for example made of plastic, which limits the propagation speed of vibrations in the direction away from the user, thereby avoiding sound losses associated with sound propagation through the sponge material of the headrest portion 16 and the headrest body 12.

[0078]

[0081] Thanks to this precaution, even when the bone conduction two-way sound transmission system is used at very high volume, sound is not transmitted to the surrounding environment.

[0079]

[0082] As shown in Figure 2, the printed circuit board 3 is also equipped with suitable sensors capable of detecting contact with and / or distance from the user's skull. In particular, the printed circuit board 3 may include:

[0083] a pressure sensor 9 suitable for quantifying the contact pressure between the user's skull and the headrest 10 (or, in the embodiment shown, more precisely, the headrest portion 16);

[0084] a proximity sensor 11 suitable for assessing the distance between the user's skull and the headrest 10 (or, in the embodiment shown, more precisely, the headrest portion 16).

[0080]

[0085] As mentioned above, the headrest portion 16 carrying the two-way sound transmission system 1 is provided with actuators for driving the movement of said headrest portion according to the measurements of the pressure sensor 9 and the measurements of the proximity sensor 11.

[0081]

[0086] Advantageously, in a preferred embodiment of the present invention, the actuator 15 can also be located on and / or connected to the same printed circuit board 3 that holds the bone conduction devices 5, 7, thereby further reducing the overall number of components in the two-way sound transmission system 1, with the advantages described above.

[0082]

[0087] In particular, the data sensed by the proximity sensor 11 can quantify how much the headrest portion 16 needs to move to fill the gap away from the user's skull.

[0083]

[0088] On the other hand, the data sensed by the pressure sensor 9 is used to find a good compromise between user comfort and a large contact area with the user's skull.

[0084]

[0089] In a preferred embodiment of the invention, where the two-way sound transmission system 1 is not located in a headrest portion separate from the rest of the headrest body, the actuator is arranged to move the entire headrest.

[0085]

[0090] In the illustrated embodiment, it is also possible to envisage the installation of a first actuator for driving the movement of the headrest portion 16 and a second actuator for driving the movement of the main body 12 of the headrest 10. In this way, it is possible to combine the movement of the main body 12 of the headrest 10 with the movement of the headrest portion 16 in order to optimally position the bone conduction two-way sound transmission system 1.

[0086]

[0091] The pressure and / or proximity sensors can be made by any technology known to those skilled in the art, including, but not limited to, capacitive, ultrasonic, piezoelectric, and radar sensors.

[0087]

[0092] The actuator for moving the headrest portion and / or the main body of the headrest is preferably an electromechanical actuator.

[0088]

[0093] It is apparent that the two-way sound transmission system 1 also includes a control unit 13 configured to send command signals to said actuators according to the data sensed by the sensors 9,11.

[0089]

[0094] Advantageously, said control unit is also provided on the same printed circuit board 3 which holds the bone conduction devices 5,7.

[0090]

[0095] The connections between the control unit 13 and the sensors 9,11 and between the control unit 13 and the actuator 15 may also be provided on the same printed circuit board 3 that holds the bone conduction devices 5,7.

[0091]

[0096] The printed circuit board 3 is also preferably equipped with an antenna (not shown) for communicating and exchanging information with the on-board computer and / or the vehicle's hi-fi system and / or the user's mobile phone via wireless communication protocols (e.g. Wi-Fi, Bluetooth, NFC).

[0092]

[0097] Furthermore, it cannot be ruled out that the printed circuit board 3 may interact with other electronic devices of the vehicle or of the user (tablets, multimedia file readers, etc.).

[0093]

[0098] On the other hand, to avoid accidental interaction with such electronic devices, the control unit 13 can be configured to switch the sound transmission system on and off.

[0094]

[0099] Thus, if the sound transmission system is turned off, the risk of accidentally triggering communication through such a system is avoided even if the user is resting his / her head against the headrest.

[0095]

[0100] Switching the sound transmission system on and off can be implemented in several ways, for example by voice command. In this case, the risk of inadvertently switching the sound transmission system on / off during a conversation should be avoided. This can be done by a special voice command, i.e. a special combination of words.

[0096]

[0101] Furthermore, the printed circuit board 3 may optionally integrate an LED 17 (also visible in Figures 1a to 1c), which when lit indicates that the bone conduction two-way sound transmission system 1 is in use and / or that the bone conduction two-way sound transmission system 1 has been switched on / off.

[0097]

[0102] The bone conduction two-way sound transmission system 1, and in particular the control unit 13, can be connected to and powered by the vehicle's battery.

[0098]

[0103] However, the possibility of integrating and using an accumulator (capacitor, electric double layer capacitor, etc.) into the printed circuit board 3 cannot be ignored, which would store energy that could be obtained from rigid / flexible solar cells placed in the area of ​​the headrest that would be exposed to light.

[0099]

[0104] From the above, it will be apparent to those skilled in the art that integrating a printed circuit board equipped with a bone conduction speaker and microphone into a headrest or part of it can provide significant advantages by enabling the user to:

[0105] - listening to sounds or music to his / her liking without being removed from the surrounding environment and without disturbing other occupants of the vehicle (or other passengers in applications for public transport vehicles);

[0106] - listening to warning / danger signals related to events that may occur both inside and outside the vehicle (in this respect, it is possible for the control unit to assign priorities to the sounds transmitted, assigning the highest priority level to said warning / danger signals);

[0107] - Having private conversations on the phone without other occupants of the vehicle being able to hear and / or respond to phone calls.

[0100]

[0108] It will also be clear to those skilled in the art that the above description has been given solely by way of non-limiting example and that several variations and modifications are possible without departing from the scope of protection defined by the appended claims.

[0101]

[0109] In particular, the invention may be applied to headrests both for car seats and for seats in other types of vehicles (trains, buses, airplanes, etc.).

Claims

1. A headrest (10) comprising a bone conduction two-way sound transmission system (1) including at least one bone conduction speaker (5) and at least one bone conduction microphone (7), the at least one bone conduction speaker (5) and the at least one bone conduction microphone (7) are arranged on the same printed circuit board (3); the at least one bone conduction speaker (5) and the at least one bone conduction microphone (7) are disposed on a first surface of the printed circuit board (3); The second, opposite side of the printed circuit board (3) is bonded to a layer made of sound absorbing material; Headrest (10).

2. The printed circuit board (3) is a flexible printed circuit board. A headrest (10) according to claim 1.

3. the at least one bone conduction speaker (5) and the at least one bone conduction microphone (7) are arranged at different locations on the same printed circuit board (3); at least one layer of sound absorbing material is provided between said at least one bone conduction speaker (5) and said at least one bone conduction microphone (7); A headrest (10) according to claim 1.

4. The bone conduction two-way sound transmission system (1) comprises one or more pressure sensors (9) and / or one or more proximity sensors (11), The pressure sensor and / or the proximity sensor are arranged on the printed circuit board (3). A headrest (10) according to claim 1.

5. the bone conduction two-way sound transmission system (1) comprises a control unit (13) that receives measurements from the one or more pressure sensors (9) and / or the one or more proximity sensors (11); The control unit is arranged on the printed circuit board (3). A headrest (10) according to claim 4.

6. The bone conduction two-way sound transmission system (1) comprises an actuator (15) or is connected to an actuator (15); the actuator is configured to receive a control signal from the control unit (13) to modify the position of the bone conduction two-way sound transmission system (1) according to the measurements of the one or more pressure sensors (9) and / or the one or more proximity sensors (11); The actuator is mounted on or connected to the printed circuit board (3). A headrest (10) according to claim 5.

7. The bone conduction two-way sound transmission system (1) includes an antenna for communication with an external electronic device via a wireless communication protocol in the headrest, The antenna is disposed on the printed circuit board (3). A headrest (10) according to claim 1.

8. the headrest comprises a body (12) and a headrest portion (16) separate from the body and connected to the body so as to be movable relative to the body; The bone conduction two-way sound transmission system (1) is received in the headrest portion (16). A headrest (10) according to any one of claims 1 to 7.

9. The headrest portion (16) is disposed below the main body (12) of the headrest. A headrest (10) according to claim 8.

10. The headrest portion (16) is made from a sponge material. A headrest (10) according to claim 8 or 9.

Images