Vehicle with sound wave reflector

Embodiments disclose a vehicle which has a vehicle ceiling having a first sound wave reflection portion having a first sound wave reflection characteristic and a second portion having a second sound wave reflection characteristic, wherein the first sound wave reflection portion is more sound wave reflecting than the second sound wave reflection portion and at least one speaker arranged in the vehicle, so that a main sound emission direction is directed to the first sound wave reflection portion, so that a sound wave emitted by the speaker and reflected by the first sound wave reflection portion is perceptible as a diffuse sound by a person in the vehicle.

BACKGROUND OF THE INVENTION

The present invention relates to a vehicle which comprises a sound wave reflector so that a sound wave emitted by a speaker and reflected at the sound wave reflector can be perceived as diffuse sound.

U.S. Pat. No. 7,424,127 B1 describes a seat mounted speaker, wherein in the backrest of the seat two electro-acoustical transducers or speaker are integrated and orientated such that the respective axes are substantially vertical to a person's head sitting on the vehicle seat. The transducers are used to facilitate the directional audio signal, such as left and right stereophonic device, which are emitted axial to the headrest in the vehicle's compartment. The integrated speaker is mainly emitting the sound waves in an axial direction of the headrest. It is the object of the U.S. patent to generate and provide an improved surround sound to passengers sitting in the vehicle.

SUMMARY

According to an embodiment, a vehicle may have: a vehicle ceiling having a first sound wave reflection portion having a first sound wave reflection characteristic and a second portion having a second sound wave reflection characteristic, wherein the first sound wave reflection portion is more sound wave reflecting than the second sound wave reflection portion; and at least one speaker arranged in the vehicle, so that a main sound emission direction is directed to the first sound wave reflection portion; wherein the first sound wave reflection portion is configured to reflect an incident sound wave, which is emitted by the at least one speaker in the main sound emission direction, in different directions for achieving a diffuse sound cloud.

According to another embodiment, a vehicle may have: a vehicle ceiling having a first sound wave reflection portion having a first sound wave reflection characteristic and a second portion having a second sound wave reflection characteristic, wherein the first sound wave reflection portion is more sound wave reflecting than the second sound wave reflection portion; and at least two speakers arranged in the vehicle, so that a main sound emission direction, is directed to the first sound wave reflection portion, so that a sound wave emitted by the speaker is reflected by the first sound wave reflection portion in different directions for achieving a diffuse sound cloud; wherein the at least two speakers are arranged in a headrest of the vehicle or in a speaker box which is attachable to a backrest or a headrest of a vehicle seat so that different sound waves are emitted by the at least two speakers in direction to the first sound wave reflection portion are de-correlated sound waves.

According to another embodiment, a vehicle may have: a vehicle ceiling having a first sound wave reflection portion having a first sound wave reflection characteristic and a second portion having a second sound wave reflection characteristic, wherein the first sound wave reflection portion is more sound wave reflecting than the second sound wave reflection portion, and wherein the first sound wave reflection portion and the second portion are formed integrally in the vehicle ceiling; and at least one speaker arranged in the vehicle, so that a main sound emission direction is directed to the first sound wave reflection portion; wherein the first sound wave reflection portion is configured to reflect an incident sound wave, which is emitted by the at least one speaker in the main sound emission direction, in different directions for achieving a diffuse sound cloud.

According to some embodiments of the invention, the vehicle comprises a vehicle ceiling, a first sound wave reflection portion and a second portion, wherein the first sound wave reflection portion is more sound wave reflecting than the second sound wave reflection portion and at least one speaker is arranged in the vehicle so that an emitted sound wave which is reflected by the first sound wave reflection portion result in a diffuse sound perception in a passenger compartment of the vehicle. The first sound wave reflection portion may be a separate element fixable at the vehicle ceiling.

According to some embodiments, the at least one speaker can be integrated in a headrest or in a speaker box which is attachable to a backrest or an normal headrest of a vehicle seat.

According to another aspect of the invention a sound processor is configured to output at least two de-correlated sound signals for two speakers arranged in a headrest of a vehicle or in a speaker box which is attachable to a backrest or a headrest of a vehicle. A de-correlator may be used to de-correlate the two output signals.

DETAILED DESCRIPTION OF THE INVENTION

As reference to the accompanyingFIGS. 1-5, explanations and embodiments relating to a vehicle with a sound wave reflector and a speaker arranged in the vehicle so that an emitted sound wave which is reflected at the sound wave reflector, is perceptible as a diffuse sound by a passenger of the vehicle.

InFIG. 1a schematic side view of a vehicle according to embodiments of the invention is depicted. The vehicle100comprises a vehicle ceiling5having a first sound wave reflection portion10, wherein the first sound wave reflection portion10has a first sound wave reflection characteristic. Furthermore, the vehicle ceiling5comprises a second portion20having a second sound wave reflection characteristic. According to embodiments the first sound wave reflection portion10is more sound wave reflecting than the second sound wave reflection portion20. In addition, at least one speaker50is arranged in the vehicle100, so that a main sound emission direction30of the speaker is directed to the first sound wave reflection portion10. As a result a sound wave, which is emitted by the speaker50, is reflected at the first sound wave reflection portion10and is perceptible as a diffuse sound by a person in the vehicle.

The expression “vehicle” may include, for example, an automobile, a bus, a train, an airplane, a ship, a subway, etc. In general, a vehicle may be any means capable for transporting persons in the air, on the water, on the ground or in the underground. The first sound wave reflection portion is also named sound wave reflector herein.

The schematic vehicle100shown inFIG. 1is, for example, an automobile having front and back seats. In other vehicles a plurality of vehicle seats may be available according to further embodiments of the invention. The at least one speaker50may be integrated, for a example, in a headrest60, which is mounted to a front seat18. The first sound wave reflection portion10and the second portion20may be formed integrally in the vehicle ceiling. Both portions, the first sound wave reflection portion10and the second portion20may form together the vehicle ceiling5or at least a part of the vehicle ceiling. The first sound wave reflection portion10and the second portion20may be made of a different material so that the first sound wave reflection characteristic is different to the second sound wave reflection characteristic of the second portion20. The first sound wave reflection characteristic describes the first sound wave reflection portion10as more sound wave reflecting than the second sound wave reflection characteristic the second portion. A sound wave which irradiates the first sound wave reflection portion10may be reflected which a smaller loss compared to a sound wave which is reflected at the second portion20.

The speaker50, which may be integrated in the headrest60, can emit during operation a sound wave in direction to the first sound wave reflection portion10, so that the emitted sound wave is reflected at the first sound wave reflection portion10. The reflected sound wave may be directed in different directions within the passenger's compartment so that a diffused sound cloud is achieved. This means, a person sitting in the vehicle can perceive an improved diffuse sound, if the emitted sound is reflected at the sound wave reflector10. It may be difficult for a passenger to locate the source of the diffused sound cloud, i.e. the at least one speaker. According to other embodiments the speaker may be arranged at a different place in the vehicle, so that a main sound emission direction30is directed to the first sound wave reflection portion10.

According to some embodiments, the material for the first sound wave reflection portion may comprise, for example, one of the materials, plastic, synthetic material, wood, metal, steel, metal sheet, glass, stone etc. The second portion10may also comprise, for example, plastic, synthetic material, metal, fabric, wood, man-made fibre or other proper materials for a vehicle ceiling. The second portion20may be made of a material having a higher sound absorption coefficient than the first sound wave reflection portion. In embodiments, the first sound wave reflection portion may have a first sound wave reflection characteristic which is different to a second sound wave characteristic of the second portion20. The fist sound wave reflection portion10may have a higher reflectivity for sound waves than the second portion. This means, the first sound wave reflection portion may have a higher sound reflection factor or coefficient than the second portion. The second portion20may be a better sound absorber than the first sound wave reflection portion10. The second portion may comprise a sound absorbing material, whereas the first sound wave reflection portion may comprise a material with a higher sound power reflection coefficient than the second portion. The second portion20may have a stronger sound absorption characteristic than the first sound wave reflection portion.

According to some embodiments, the first sound wave reflection portion10can be made of a material which is harder than the material of the second portion20, so that a sound wave is reflected from the first sound wave reflection portion with less losses compared to a sound wave reflected at the second portion. The hardness of the first sound wave reflection portion10having a first sound wave reflection characteristic may be higher than a hardness of the second portion20having a second sound wave reflection characteristic.

The shape of the first sound wave reflection portion10, which can be integrated in the vehicle ceiling5or which can be a separate element which is fixed at the vehicle ceiling5, may be, for example, rectangular, round, ellipsoid, triangular, trapezoid or polygonal.

According to some embodiments, the surface of the first sound wave reflection portion10is different to a surface of the second portion20. The first sound wave reflection portion and the second portion can be made of the same or a different material, but the first sound wave reflection portion may have a different surface than a second portion according to some embodiments. The structure of the surfaces of the first sound wave reflection portion and the second portion may be different. Because of the different surfaces, the first sound wave reflection portion may be more sound wave reflecting than the second portion, if a sound wave is incident to the first sound wave reflection portion and to the second portion.

The first sound wave reflection portion10may have a size between 50 cm2to 10,000 cm2, 100 cm2to 3,000 cm2or between 200 cm2to 1,000 cm2. In some embodiments, the first sound wave reflection portion is arranged above the at least one speaker50in the vehicle100. This means, the at least one speaker50can irradiate a sound wave upwardly in direction to a vehicle ceiling so that the sound wave is reflected at the first sound wave reflection portion10. The first sound wave reflection portion may be mounted, fixed or integrated in the vehicle ceiling5. In some embodiments, a first sound wave reflection portion10may be a separate element which can be fixed at the vehicle ceiling5. The second portion20may be the surrounding vehicle ceiling. The first sound wave reflection portion may be mounted directly above a speaker which is incorporated in a headrest or in a speaker box which is attachable to the headrest or to a backrest of a vehicle seat. During operation, the speaker is then emitting upwardly a sound wave mainly to the first sound wave reflection portion. In general, a main sound emission direction30of the at least one speaker50may be directed to the first sound wave reflection portion10, so that an emitted sound wave hits mainly the first sound wave reflection portion10. The speaker50may be arranged inclined with respect to a vehicle wall and a main sound emission direction may be directed to the sound wave reflector.

InFIG. 2, a further schematic side view of a vehicle according to an embodiment of the invention is depicted. In this embodiment the first sound wave reflection portion10may be a separate element which is mounted to the vehicle ceiling5, wherein the vehicle ceiling is forming the second portion20. The first sound wave reflection portion10can be, for example, mechanically fixed to the vehicle ceiling. The surrounding vehicle ceiling area may form the second portion20, as described herein. The first sound wave reflection portion10may comprise a surface which is, for example, at least partly formed convex, so that an incident sound wave which is reflected at the convex portion is reflected in different directions in a passenger's compartment. As a consequence, a person in the vehicle may have a diffuse sound perception, i.e. the person may not be able to exactly locate the position of the speaker. The sound wave reflector may have a rectangular shape and a convex surface. The thickness D of the convex sound wave reflector at the vertex or a distance D between the vehicle ceiling and the vertex may be, for example, between 0.5 cm and 5 cm, e.g. about 1 cm. The sound wave reflector can be, for example, a metal or plastic sheet which is convex curved, wherein the distance D from the vehicle ceiling to the vertex11or apex of the convex curved sheet is between 0.5 cm and 5 cm.

According to some embodiments inFIG. 3, the speaker50may be integrated in a headrest60, for a vehicle seat or in a speaker box70, which can be attached to a headrest or to a backrest of a vehicle seat. InFIG. 3, the headrest60or the speaker box70comprise two speakers50, which are lowered arranged in the headrest or in the speaker box, so that sound waves which are emitted from the single speakers are mixed in the chamber25. By means of the lowered speaker in the chamber25a de-correlated diffuse sound cloud can be generated which is then reflected via the first sound wave reflection portion10into the passenger's compartment, so that a person in the vehicle has a diffuse sound perception.

According to some embodiments, the vehicle100may comprise at least two speakers50arranged in a headrest60or in a speaker box70, wherein the speaker box is attachable to a backrest or an usual headrest of a vehicle seat, so that different sound waves emitted by the at least two speakers and which are reflected by the first sound wave reflection portion10are perceptible as de-correlated sound waves. The speakers50may be lowered arranged in the headrest as it is shown inFIG. 3or according to further embodiments in a speaker box which can be fixed at an usual headrest or a vehicle seat. According to other embodiments, the speakers are not lowered in a headrest of the vehicle or in a speaker box.

The at least one speaker50may be arranged in a chamber25formed in the headrest or a speaker box70. The chamber may have a sound outlet opening, so that a sound wave emitted in a main sound emission direction30by a speaker during operation hits the first sound wave reflection portion10. As it is shown inFIG. 3, the sound outlet opening may consist, for example, of a missing top side wall of the chamber25or speaker box.

InFIG. 3, the at least one speaker50is arranged in an open top chamber25, so that an emitted sound wave can escape in a upwardly direction. In other embodiments the sound outlet opening may be formed, for example, by slots or holes in a wall of the headrest or speaker box.

InFIG. 4another embodiment of a speaker, which is arranged in a headrest of a seat for a vehicle is depicted. In this embodiment, again two speakers50a,50bare arranged in a headrest60or in a speaker box70and furthermore two bass-reflex-tubes65are also integrated in the headrest60, respectively in the speaker box70. By means of the bass reflex tubes, the emitted sound may be more saturated.

The at least one speaker50may be part of an audio sound system of the vehicle. Such an audio sound system may, for example, comprise a sound processor which is configured to output two de-correlated sound signals. A first signal for a first speaker50ain a headrest60, or in a speaker box70, attachable to a backrest or a headrest of a vehicle seat and a second sound signal for a second speaker50bin a headrest60or in a speaker box70, attachable to a backrest or an usual headrest of a vehicle seat. The first and the second sound signals may be different sound signal. This means, the speakers50a,50bmay emit different sound signals which can be, for example, in the above-mentioned chamber25mixed, so that a de-correlated sound wave can be emitted in direction to the first sound wave reflection portion10. The chamber25may act as a de-correlator for generating a first output signal being de-correlated from a second output signal. The de-correlator may be formed by the chamber, comprising the lowered arranged first and second speakers50aand50b. In general, the sound processor may further comprise a de-correlator for generating a first output signal being de-correlated from a second output signal.

InFIG. 5, a photo of a part of a vehicle100with a vehicle ceiling5having a first sound wave reflection portion10a,band a second portion20having a second sound wave reflection characteristic and at least one speaker50, which, in this embodiment, is arranged in the headrest60or speaker box70. The speaker box70may be, for example, mechanically fixable to an usual headrest or to a backrest of a vehicle seat18. In the automobile shown inFIG. 5, the sound wave reflector10ais, for example, arranged above a first front seat and a second sound wave reflector10bis arranged above a second front seat of the automobile. In other embodiments, a sound wave reflector10, respectively a first sound wave reflection portion10may be arranged above rear seats of a vehicle. In other vehicles, for example, in airplanes or ships, there may be a plurality of first sound wave reflection portions arranged at a vehicle ceiling. In some embodiments, a common first sound wave reflection portion may be assigned to a plurality of a vehicle seats. Each vehicle seat may comprise, for example, a headrest with at least one speaker, wherein the main sound emission direction of the speaker is directed to the common first sound wave reflection portion10.

According to an aspect of the invention, the sound processor is configured to output de-correlated sound signals—a first signal for a first speaker in a headrest or in a speaker box, attachable to a backrest or a headrest of a vehicle seat and a second sound signal for a second speaker in the headrest or in the speaker box. In general, the vehicle100may comprise a plurality of speakers which are controlled by a sound processor, respectively, an audio sound system which controls different sound channels.

Embodiments of the invention also concern a headrest speaker arrangement. A novel speaker arrangement in headrests and the control of the same is described herein, which is according to some embodiments for a three-dimensional sound reproduction, in small space volumes, e.g. in a passengers compartment or an auto cabin, particular well sufficient.

According to some embodiments, two speakers are built-in in a headrest of a seat, for example, a vehicle seat. If a vehicle comprises four seats, the two headrests of the front seats can be sufficient. The speakers can irradiate upwards to a ceiling of the vehicle. According to some embodiments, at the ceiling of the vehicle, for example, above the headrest a harder region than the surrounding usual vehicle ceiling is installed in order to achieve a good reflection of the emitted sound waves. The harder region10, may be, for example, a plastic plate. The harder region10is described herein, also as a sound wave reflector10or first sound wave reflection portion10which can be mounted at the vehicle ceiling above the headrest. The surface of the sound wave reflector can be slightly curved convex —, for example, about 1 cm—in order to support a diffuse sound irradiation. The size of the sound wave reflector may be, for example, 340×180 mm.

According to other embodiments, the area of the sound wave reflector may be, for example, between 50 cm2and 10000 cm2or between 100 cm2and 2000 cm2The sound wave reflector10may have, for example, a quadratic, a rectangular, a round or a trapezoid shape. The usage of the headrests allows to use sufficient large speakers with a not too small volume behind. This can be of advantage to achieve a sufficient lower cut-off frequency of, from e.g. 150 Hz. In order to reproduce a de-correlated stereophonic signal per person, two speakers per headrest have to be used. Above the speakers in the headrest there is one common chamber space9for both speakers.

Because of a lowering of the speakers with respect to a top edge from at least 40 mm in the headrest and by the mixture of both speaker signals in the resulting chamber9and by the partial radiation via the reflector10, the speaker50itself cannot be located and a desired diffuse sound cloud from an upper side can be achieved. This applies for a person in front of the headrest, as well as, for a person behind the headrest on a rear seat with respect to the sound perception. An extension of this sound cloud and a three-dimensional perception can be achieved by other speakers in the reproduction space by the reproduction via further pairs of de-correlated signals.

According to embodiments, the at least one speaker in a headrest of a vehicle seat or a speaker box, as described herein, may be part of a larger audio sound system, which includes further speakers distributed in a vehicle's compartment.