HEADREST PROVIDED WITH A SYSTEM FOR TWO-WAY SOUND TRANSMISSION BY BONE CONDUCTION

Abstract

A headrest having a bone conduction two-way sound transmission system is provided. The system has a bone conduction speaker and bone conduction microphone mounted on the same printed circuit board. Additional components of the bone conduction two-way sound transmission system, such as a control unit, contact sensors or proximity sensors, and an antenna for communication with external electronic devices can be mounted on the same printed circuit board. Assembling the components of the system is easy and subsequent assembling the two-way sound transmission system inside the headrest is simpler, faster, and less subject to human errors, thus increasing the quality of the final product while keeping the manufacturing costs low.

Claims

1. A headrest for vehicle seats, comprising a bone conduction two-way sound transmission system, which in turn comprises at least one bone conduction loudspeaker and at least one bone conduction microphone, wherein the at least one bone conduction speaker and the at least one bone conduction microphone is arranged on a same printed circuit board.

2. The headrest according to claim 1, wherein the printed circuit board is a flexible printed circuit board.

3. The headrest according to claim 1, wherein the at least one bone conduction speaker and the at least one bone conduction microphone are arranged at different locations on the same printed circuit board, at least one layer of sound absorbing material being provided between the at least one bone conduction speaker and the at least one bone conduction microphone.

4. The headrest according to claim 1, wherein the printed circuit board has a first face and a second, opposite face, wherein the at least one bone conduction speaker and the at least one bone conduction microphone are arranged on the first face of the printed circuit board, and wherein the second, opposite face of the printed circuit board is coupled to a layer made of sound-absorbing material.

5. The headrest according to claim 1, wherein the bone conduction two-way sound transmission system comprises one or more pressure sensors, and wherein the pressure sensors are arranged on the printed circuit board.

6. The headrest according to claim 5, wherein the bone conduction two-way sound transmission system comprises a control unit, which receives the measurements from the one or more pressure sensors, and wherein the control unit is arranged on the printed circuit board.

7. The headrest according to claim 6, wherein the bone conduction two-way sound transmission system is provided with actuators, which actuators receive control signals from the control unit in order to modify the position of the bone conduction two-way sound transmission system according to the measurements of the one or more pressure sensors, and wherein the actuators are mounted on the printed circuit board.

8. The headrest according to claim 1, wherein the bone conduction two-way sound transmission system comprises an antenna for communication with electronic devices external to the headrest via wireless communication protocols, and wherein the antenna is arranged on the printed circuit board.

9. The headrest according to claim 1, wherein the headrest comprises a main body and a headrest portion, which is made as a piece separate from the main body, is connected to the main body, and is movable relative to the main body, and wherein the bone conduction two-way sound transmission system is received in the headrest portion.

10. The headrest according to claim 9, wherein the main body has an upper part and a lower part, and wherein the headrest portion is arranged at the lower part of the main body of the headrest.

11. The headrest according to claim 9, wherein the headrest portion is made of a spongy material.

12. The headrest according to claim 9, wherein the headrest portion is made of shape memory foam.

13. The headrest according to claim 6, wherein the bone conduction two-way sound transmission system is provided with actuators, which actuators receive control signals from the control unit in order to modify the position of the bone conduction two-way sound transmission system according to the measurements of the one or more pressure sensors, and wherein the actuators are connected to the printed circuit board.

14. The headrest according to claim 1, wherein the bone conduction two-way sound transmission system comprises one or more proximity sensors, and wherein the one or more proximity sensors are arranged on the printed circuit board.

15. The headrest according to claim 14, wherein the bone conduction two-way sound transmission system comprises a control unit, which receives the measurements from the one or more pressure proximity sensors, and wherein the control unit is arranged on the printed circuit board.

16. The headrest according to claim 15, wherein the bone conduction two-way sound transmission system is provided with actuators, which actuators receive control signals from the control unit in order to modify the position of the bone conduction two-way sound transmission system according to the measurements of the one or more proximity sensors, and wherein the actuators are mounted on the printed circuit board.

17. The headrest according to claim 15, wherein the bone conduction two-way sound transmission system is provided with actuators, which actuators receive control signals from the control unit in order to modify the position of the bone conduction two-way sound transmission system according to the measurements of the one or more proximity sensors, and wherein the actuators are connected to the printed circuit board.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0052] Further features and advantages of the invention will become more evident from the detailed description of a preferred embodiment, given by way of non-limiting example, with reference to the accompanying drawings, in which:

[0053] FIG. 1a schematically shows a headrest according to the invention, shown in a first working position;

[0054] FIG. 1b schematically shows a headrest according to the invention, shown in a second working position;

[0055] FIG. 1 c schematically shows a headrest according to the invention, shown in a third working position;

[0056] FIG. 2 schematically shows the bone conduction two-way sound transmission system of FIGS. 1a-1c.

DESCRIPTION OF EMBODIMENTS

[0057] In the following description of a preferred embodiment of the invention, reference will be made to an application to a headrest for a motor vehicle seat.

[0058] It is understood that this application must not be understood in a limiting sense and several other applications to headrest for other types of seats can be envisaged.

[0059] FIGS. 1a-1c schematically show a headrest 10 according to the invention.

[0060] In a per se known way, said headrest 10 comprises a main body 12 mounted on a single central body or on two rods 14 and connected through it/them to the backrest of the corresponding seat.

[0061] The main body 12 of the headrest 10 preferably has an anatomical shape and is mounted in an adjustable manner on the single central body or on the rods 14, so that its position can be adapted to the morphology of the user.

[0062] More particularly, the main body 12 of the headrest 10 can be adjustable in height and/or in orientation around a horizontal axis parallel to the seat backrest. For the reasons that will be clarified hereinafter, said main body is preferably adjustable at least in orientation about said horizontal axis parallel to the seat backrest.

[0063] According to the invention, the headrest 10 is equipped with a bone conduction two-way sound transmission system, which will be described in detail below.

[0064] In the preferred embodiment of the invention described and illustrated herein, said bone conduction two-way sound transmission system is mounted in a headrest portion 16 which is separated from the main body 12 of said headrest and is connected to said main body so as to be movable relative to it.

[0065] The headrest portion 16 carrying the bone conduction two-way sound transmission system is preferably arranged at the lower part of the main body 12 of the headrest, so that it can be brought into contact with the occipital region of the user's skull rather than with its parietal region.

[0066] Indeed, experimental tests have shown that the bone conduction two-way sound transmission is optimal when the contact occurs at the occipital region.

[0067] In a particularly simple embodiment of the invention, it is possible to provide that the headrest portion 16 is manually moved by the user to bring it into contact with his/her own skull.

[0068] However, in the preferred embodiment of the invention, the movement of said headrest portion 16 is obtained by means of suitably controlled actuators capable of obtaining translation and/or rotation movements of said headrest portion with respect to the main body of the headrest itself.

[0069] Thanks to these actuators—the operation of which will be described in greater detail below—the headrest portion 16 carrying the bone conduction two-way sound transmission system can be selectively brought from a rest position (see [FIG. 1a]), in which it is spaced away from the user's skull, to an operating position (see FIGS. 1b and 1c), in which it is in contact with the occipital region of the user's skull.

[0070] In this way, when the bone conduction two-way sound transmission system is not in use, the headrest portion 16 does not interfere with the comfort of the user, while when the bone conduction two-way sound transmission system is in use the correct contact with the user's skull is guaranteed.

[0071] The headrest portion 16 is preferably made of spongy material, even more preferably of shape memory foam. In this way, when said headrest portion comes into contact with the user's skull, it fits to the specific morphology of the user's skull, so as to increase the contact area with the skull itself and ensure optimal operation of the bone conduction devices.

[0072] In a particularly preferred embodiment of the invention, the front part of the headrest portion 16, facing the user's skull and intended to come into contact with it, is made of a spongy material, preferably a shape memory foam, while the rear part of the headrest portion 16, far from the user's skull, is made of sound-absorbing material. Thanks to this precaution, even if the bone conduction two-way sound transmission system is used at a very high volume, the sound will not be transmitted to the surrounding environment.

[0073] The bone conduction two-way sound transmission system 1 of the headrest 10 according to the invention is schematically shown in [FIG. 2].

[0074] Said two-way sound transmission system 1 comprises at least one bone conduction speaker 5 and at least one bone conduction microphone 7 and, according to the invention, said at least one bone conduction loudspeaker 5 and said at least one bone conduction microphone 7 are positioned on one and the same printed circuit board 3.

[0075] The conduction loudspeaker 5 and the bone conduction microphone 7 are positioned on the printed circuit board 3 at different locations, so as to avoid undesired interferences and disturbances between input signals and output signals.

[0076] Preferable, a layer of sound adsorbing material is arranged between the conduction loudspeaker 5 and the bone conduction microphone 7, so that the risk of undesired interferences and disturbances between input signals and output signals is further reduced.

[0077] With respect to known solutions, providing a single printed circuit board that carries both the bone conduction speakers and the bone conduction microphones provides for flexibility in the design of the geometries and shapes of the headrest, ease of mounting the device in the seat headrest, reduction of assembly time and better quality in assembly (due to the reduction of human errors).

[0078] Although the printed circuit board 3 may be a rigid printed circuit board, it preferably is a flexible printed circuit board.

[0079] Using a flexible printed circuit board advantageously allows to adapt the conformation of the board itself in order to obtain the optimal positioning of the bone conduction devices in the headrest portion 16.

[0080] Moreover, in a flexible printed circuit board undesired vibrations are dampened thanks to the flexibility of the printed circuit board, which helps in preventing interferences and disturbances between input signals and output signals, and also reduces mechanical stresses on the components of the loudspeaker and microphone.

[0081] In any case, it cannot be excluded that the printed circuit board 3 is obtained by means of a combination of rigid parts and flexible parts.

[0082] [FIG. 2] shows a pair of bone conduction speakers 5, symmetrically arranged on the printed circuit board 3, and a bone conduction microphone 7. However, this configuration should not be construed as limiting and the bone conduction two-way sound transmission system 1 may comprise any desired number of bone conduction devices: the person skilled in the art will be able to identify a correct compromise between the efficiency of the two-way sound transmission and the complexity of the system.

[0083] On the face opposite to the face carrying the bone conduction devices 5, 7 (i.e. on the face furthest from the user), the printed circuit board 3 can then be advantageously coupled to a layer of sound-absorbing material, for example of plastic. This layer of sound-absorbing material allows to limit the speed of propagation of vibrations in the direction opposite to the user and thus to avoid sound losses related to the propagation of sound through the spongy material of the headrest portion 16 and of the headrest main body 12.

[0084] Thanks to this precaution, even if the bone conduction two-way sound transmission system is used at a very high volume, the sound will not be transmitted to the surrounding environment.

[0085] As shown in [FIG. 2 ], the printed circuit board 3 is also equipped with appropriate sensors capable of detecting contact with the user's skull and/or distance from the user's skull. In detail, the printed circuit board 3 may comprise: [0086] a pressure sensor 9, suitable for quantifying the contact pressure between the user's skull and the headrest 10 (or more precisely the headrest portion 16 in the shown embodiment); [0087] a proximity sensor 11, suitable for evaluating the distance between the user's skull and the headrest 10 (or more precisely the headrest portion 16 in the shown embodiment).

[0088] As mentioned above, the headrest portion 16 carrying 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 of the proximity sensor 11.

[0089] Advantageously, in a preferred embodiment of the invention said actuators 15 can also be arranged on and/or connected to the same printed circuit board 3 that carries the bone conduction devices 5, 7, which further reduces the overall number of components of the two-way sound transmission system 1, with the advantages set forth above.

[0090] In detail, the data detected by the proximity sensor 11 allow to quantify how much the headrest portion 16 has to move to fill the gap separating it from the user's skull.

[0091] On the other hand, the data detected by the pressure sensor 9 are used to find a good compromise between the user's comfort and a large contact surface with the user's skull.

[0092] In embodiments of the invention in which the two-way sound transmission system 1 is not mounted in a headrest portion separate from the rest of the headrest body, the actuators will be configured to move the whole headrest.

[0093] In the illustrated embodiment, it is also possible to foresee the provision of first actuators for driving the movement of the headrest portion 16 and of second actuators for driving the movement of the main body 12 of the headrest 10. In this way, it will be possible to combine the movements of the main body 12 of the headrest 10 and those of the headrest portion 16 in order to optimally position the bone conduction two-way sound transmission system 1.

[0094] The pressure sensors and/or proximity sensors can be made according to any technology known to the person skilled in the art. Non-limiting examples of such technologies include capacitive sensors, ultrasonic sensors, piezoelectric sensors, radar sensors.

[0095] The actuators for operating the headrest portion and/or the main body of the headrest are preferably electro-mechanical actuators.

[0096] It is evident that the two-way sound transmission system 1 will also comprise a control unit 13 configured to send command signals to said actuators according to the data detected by the sensors 9, 11.

[0097] Advantageously, said control unit is also provided on the same printed circuit board 3 that carries the bone conduction devices 5, 7.

[0098] The connections between the control unit 13 and the sensors 9, 11 and the connections between the control unit 13 and the actuators 15 can also be provided on the same printed circuit board 3 that carries the bone conduction devices 5, 7.

[0099] Said printed circuit board 3 will also preferably be equipped with an antenna (not shown) which communicates and exchanges information with the on-board computer and/or with the vehicle hi-fi system and/or with the user's mobile phone through wireless communication protocols (for example Wi-Fi, Bluetooth, NFC).

[0100] Furthermore, it is not to be excluded that said printed circuit board 3 can interact with other electronic devices of the vehicle or of the user (tablet, multimedia file reader, etc.).

[0101] On the other hand, in order to avoid accidental interactions with such electronic devices, the control unit 13 can be arranged for switching on and off the sound transmission system.

[0102] Accordingly, when the sound transmission system is switched off, the risk of accidentally triggering a communication through such system is avoided, even if the user's is leaning his/her head against the headrest.

[0103] Switching on/off the sound transmission system can be implemented in several ways, for instance by a voice command. In this case, the risk of inadvertently switching on/off the sound transmission system while speaking should be avoided: this can be done by a special voice command, i.e. a special combination of words.

[0104] Furthermore, said printed circuit board 3 can optionally integrate LEDs 17 (also visible in FIGS. 1a-1c) which, if lit, indicate 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 is switched on/off.

[0105] The bone conduction two-way sound transmission system 1—and in particular the control unit 13—can be connected to the vehicle battery and powered by it.

[0106] However, it is not to be excluded the possibility of using accumulators (capacitors, supercapacitors, etc.) to be integrated into the printed circuit board 3, which accumulators store energy that can be obtained from rigid/flexible solar cells arranged in areas of the headrest exposed to light.

[0107] From the above description it will be evident to the person skilled in the art that integrating a printed circuit board equipped with bone conduction speakers and microphones in the headrest or in a portion thereof allows to obtain considerable advantages, as the user can: [0108] listen to sounds or music to his/her liking, without however becoming estranged from the surrounding environment and disturbing the other occupants of the vehicle (or other passengers in the case of applications to vehicles for public transport service); [0109] listen to warning/danger signals related to events that may occur both inside and outside the vehicle (in this regard it is possible to provide that the control unit is able to assign a priority order to the transmitted sounds, assigning the highest priority level to said warning/danger signals); [0110] have private telephone conversations, without the other occupants of the vehicle being able to hear and/or interact in the telephone call.

[0111] It will also be evident to the person skilled in the art that the above description has been given only by way of non-limiting example and that several variants and modifications are possible, without departing from the scope of protection defined by the attached claims.

[0112] In particular, the invention may be applied both to headrests for car seats, and to headrests for seats of other types of vehicles (trains, buses, airplanes, etc.).