US20080129094A1

US20080129094A1 - Vibro-acoustic system

Info

Publication number: US20080129094A1
Application number: US11/948,974
Authority: US
Inventors: Yuichi Nakajima
Original assignee: Denso Ten Ltd
Current assignee: Denso Ten Ltd
Priority date: 2006-12-01
Filing date: 2007-11-30
Publication date: 2008-06-05
Also published as: CN101193454A; JP2008141477A

Abstract

The present invention is directed to providing a vibro-acoustic system that can be used for an extended period of time by reducing the uncomfortable feeling or sensation of pressure that a user may experience during use. The vibro-acoustic system comprises: a seat having a seatback and a seat proper; a band dividing circuit which produces a first sound signal and a second sound signal by dividing an input sound signal into frequency bands; a first vibrating device which vibrates in accordance with the first sound signal, and which is mounted in the seatback so that the direction of vibration of the first vibrating device is parallel or substantially parallel to the occupant-side surface of the seatback; and a second vibrating device which vibrates In accordance with the second sound signal, and which is mounted in the seat proper so that the direction of vibration of the second vibrating device is parallel or substantially parallel to the occupant-side surface of the seat proper.

Description

This application is a new U.S. patent application that claims benefit of JP 2006-325606, filed on Dec. 1, 2006, the entire content of JP 2006-325606 is hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a vibro-acoustic system, or more specifically to a vibro-acoustic system for mounting in a vehicle seat.

BACKGROUND ART

A vibro-acoustic system generally known as “Bodysonic” comprises a means for providing physically perceptible vibrations and a speaker both mounted in a chair, a cushion, or the like, and a user can easily experience a dynamic sensation and realistic feeling playbacked sounds.
An apparatus is known in which such a vibro-acoustic system is used in a vehicle seat (for example, refer to patent document 1). In the system described in patent document 1, a transducer is mounted on a structural frame of the vehicle seat so that the vibration of the transducer is transmitted to the occupant of the seat via the frame.
However, with this apparatus, since the transducer vibrates in a direction directly opposed to the direction of the occupant, there has been the problem that the occupant, when subjected to the vibrations for an extended period of time, may feel an unpleasant sensation and may experience, for example, an uncomfortable feeling or sensation of pressure. This has presented a serious problem particularly in the case of vehicle seats where the occupants have to stay seated for a long period of time.
Patent document 1: Japanese Utility Model Publication No. H06-23389 (FIG. 1)

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a vibro-acoustic system that can solve the above problem.
It is another object of the present invention to provide a vibro-acoustic system that can be used for an extended period of time by reducing an uncomfortable feeling or sensation of pressure that the user may experience during use.
A vibro-acoustic system according to the present invention comprises: a seat having a seatback and a seat proper; and a vibrating device which vibrates in accordance with an applied sound signal, wherein the vibrating device is mounted in the seat so that the direction of vibration of the vibrating device is parallel or substantially parallel to the occupant-side surface of the seatback or the seat proper.
Further, a vibro-acoustic system according to the present invention comprises: a seat having a seatback and a seat proper; a band dividing circuit which produces a first sound signal and a second sound signal by dividing an input sound signal into frequency bands; a first vibrating device which vibrates in accordance with the first sound signal, and which is mounted in the seatback so that the direction of vibration of the first vibrating device is parallel or substantially parallel to the occupant-side surface of the seatback; and a second vibrating device which vibrates in accordance with the second sound signal, and which is mounted in the seat proper so that the direction of vibration of the second vibrating device is parallel or substantially parallel to the occupant-side surface of the seat proper.
Preferably, the vibro-acoustic system according to the present invention further comprises a source which produces the sound signal.
According to the vibro-acoustic system of the present invention, since each vibrating device that vibrates is mounted so that the direction of its vibration is not perpendicular to the occupant-side surface of the seatback or the seat proper, i.e., the direction of vibration is parallel or substantially parallel to the surface, the system can be used for an extended period of time without causing very much discomfort or sensation of pressure to the occupant.
Furthermore, according to the vibro-acoustic system of the present invention, since the sound signal from the source is divided into frequency bands, and the vibrating devices mounted separately in the seat are driven independently of each other, more dynamic and realistic sensations can be provided to the user.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1( a) is a diagram explaining the operation of a vibro-acoustic system according to the present invention, and FIG. 1( b) is a diagram explaining the operation of a vibro-acoustic system according the prior art.

FIG. 2 is a block diagram showing the general configuration of the vibro-acoustic system 100 according to the present invention.

FIG. 3 is a diagram showing an example in which vibrating devices are mounted in a vehicle seat.

FIG. 4 is a diagram showing the arrangement of the vibrating devices as viewed from the back of the vehicle seat.

FIG. 5 is a diagram showing another mounting example of the vibrating devices.

FIG. 6 is a diagram showing still another mounting example of the vibrating devices.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A vibro-acoustic system according to the present invention will be described below with reference to the drawings. However, it should be noted that the scope of the present invention is not limited by the specific embodiments described herein, but may be defined by the appended claims and their equivalents.
FIG. 1 is a diagram explaining the operation of the vibro-acoustic system according to the present invention.
FIG. 1( a) shows an example in which a vibrating device 1 used in the vibro-acoustic system of the present invention is mounted in a seat 10, while FIG. 1( b) shows an example in which a conventional Bodysonic-type transducer 2 and a vibrating plate 3 are mounted in the seat 10. Here, seat 10 comprises a headrest 11, a seatback 12, and a seat proper 13.
Unlike conventional transducer 2, vibrating device 1 contains a vibrator that has an increased thickness and a cylindrical shape and that vibrates in a direction parallel to the longitudinal direction of the vibrating device. The vibrator is designed so that the intensity of its vibration varies in accordance with the sound signal applied to the vibrating device 1. Accordingly, when a sound signal is applied to the vibrating device 1, the vibrating device vibrates in accordance with the applied sound signal.
In FIG. 1( a), the vibrating device 1 is mounted vertically in the seatback 12 of the seat 10. When a sound signal is applied to the vibrating device 1, the vibrating device 1 vibrates in the direction indicated by arrow A shown in FIG. 1( a); as a result, the vibration propagates along the vertical direction of the seatback 12, causing the entire structure of the seatback 12 to vibrate, and the resulting vibration is transmitted to the occupant of the seat 10. In other words, the vibrating device 1 is mounted so that the direction of its vibration is not perpendicular to the occupant-side surface of the seatback 12, i.e., the direction of vibration is parallel or substantially parallel to the surface. Accordingly, the occupant can feel very soft vibrations, and even when the occupant stays seated for an extended period of time in the seat 10 equipped with the vibrating device 1, the occupant does not experience an uncomfortable feeling or a sensation of pressure.
In FIG. 1( b), the transducer 2 causes the vibrating plate 3 to vibrate, and the vibration of the vibrating plate 3 directly strikes the occupant's back; this structure can easily produce strong vibrations, but when subjected to vibrations for an extended period of time, the occupant may have an uncomfortable feeling or a sensation of pressure. In other words, the conventional transducer 2 is mounted so that the direction of its vibration (the direction indicated by arrow B) is perpendicular to the occupant-side surface of the seatback 12.
In this way, according to the vibro-acoustic system of the present invention, since the vibrating device 1 is mounted so that the direction of its vibration is not perpendicular to the occupant-side surface of the seatback 12 (or the seat proper 13) but is parallel or substantially parallel to the surface, the vibrations do not directly strike the occupant's back, and the occupant does not experience an uncomfortable feeling or a sensation of pressure even when the occupant stays seated for an extended period of time.
FIG. 2 is a block diagram showing the general configuration of the vibro-acoustic system 100 according to the present invention.
The vibro-acoustic system 100 comprises a source 110, a waveform extracting circuit 120, an FFT circuit 130, a band dividing circuit 140, an amplifying unit 150, and vibrating devices 160 to 169.
The source 110 which produces a sound signal may be one or a plurality of sources selected from among a CD/MD playback unit, a radio receiver unit, a TV receiver unit, a DVD playback unit, an HD (Hard Disk) playback unit, and a navigation unit.
The waveform extracting circuit 120 extracts the waveform of the sound signal output from the source 110, the FFT circuit 130 extracts the sound signal for each frequency band, and the band dividing circuit 140 divides the sound signal into three predetermined bands, i.e., the first mid-to-low frequency band (150 to 200 Hz), the second mid-to-low frequency band (100 to 150 Hz), and the low frequency band (50 to 100 Hz), for output to the amplifier circuit 150.
The band dividing circuit 140 distributes the sound signal in the first mid-to-low frequency band (150 to 200 Hz) to a first vibrating device group consisting of the vibrating devices 160 and 161, the sound signal in the second mid-to-low frequency band (100 to 150 Hz) to a second vibrating device group consisting of the vibrating devices 162 and 163, and the sound signal in the low frequency band (50 to 100 Hz) to a third vibrating device group consisting of the vibrating devices 164 to 169. Each of the vibrating devices 160 to 169 used here is identical to the vibrating device 1 described with reference to FIG. 1( a).
The amplifier circuit 150, which is paired with the vibrating devices 160 to 169, amplifies the sound signals output from the band dividing circuit 140 and outputs them to the respective vibrating devices.
Though not shown in FIG. 2, the vibro-acoustic system 100 includes a plurality of speakers for reproducing sound signals higher than the first mid-to-low frequency band signal (150 to 200 Hz). It will also be noted that the vibro-acoustic system 100 need not necessarily include the source 110 and/or the vibrating devices 160 to 169.
FIG. 3 is a diagram showing an example in which the vibrating devices are mounted in a vehicle seat.
As shown in FIG. 3, the vibrating devices 160 and 161 of the first vibrating device group are mounted in the upper half of the seatback 12 at positions spaced apart from the centerline A of the seatback 12, the vibrating devices 162 and 163 of the second vibrating device group are mounted in the lower half of the seatback 12 at positions spaced apart from the centerline A of the seatback 12, the vibrating devices 164 to 167 of the third vibrating device group are mounted in the seat proper 13 at positions spaced apart from the centerline A of the seat proper 13, and the vibrating devices 168 and 169 of the third vibrating device group are mounted in the forward end portion of the seat proper 13. All of the vibrating devices are mounted by avoiding the positions where the occupant's back or buttocks directly contact the seatback 12 or the seat proper 13 when the occupant is seated in the seat 10.
FIG. 4 is a diagram showing the arrangement of the vibrating devices as viewed from the back of the vehicle seat.
As shown in FIG. 4, the vibrating devices 160 to 163 are mounted so as to be embedded in a polyurethane foam 15 which is a seat material supported by such means as springs and the seat frame 14 of the seat 10. Preferably, the vibrating devices are mounted by first forming recesses each slightly smaller than each vibrating device in the polyurethane foam 15 and then pushing the vibrating devices into the respective recesses in the polyurethane foam, because the vibrations from the vibrating devices can then be transmitted effectively to the seat. Since the recent trend is to reduce the thickness of the vehicle seat 10, embedding the vibrating devices in polyurethane foam is also preferable from the standpoint of securing space for mounting the vibrating devices.
The hardness of the polyurethane form is in the range of 10 to 350 N, which is sufficient to transmit the vibrations of the vibrating devices. Here, either rigid urethane or soft urethane may be used as long as it is foamed urethane.
Though not shown in FIG. 4, the vibrating devices 164 to 169 mounted in the seat proper 13 are likewise embedded in the polyurethane foam of the seat proper 13.
Next, the operation of the vibro-acoustic system 100 will be described.
Referring to the configuration shown in FIG. 2, the sound signal input from the source 110 is divided into three frequency bands, the first mid-to-low frequency band (150 to 200 Hz), the second mid-to-low frequency band (100 to 150 Hz), and the low frequency band (50 to 100 Hz), and the sound signals of the respective frequency bands are distributed to the first to third vibrating device groups, respectively. The vibrating devices of the first to third vibrating device groups vibrate in accordance with the applied sound signals, and vibrations providing a dynamic sensation and a realistic feeling can thus be transmitted to the occupant of the seat 10. As earlier described, all of the vibrating devices 160 to 169 are mounted by avoiding positions where the occupant's back or buttocks directly contact the seatback 12 or the seat proper 13 when the occupant is seated in the seat 10. As a result, the vibrations can be transmitted indirectly to the occupant, reducing the possibility of giving the occupant an uncomfortable feeling or a sensation of pressure even when the system is used for an extended period of time.
The reason that the vibrating devices corresponding to the first mid-to-low frequency band (150 to 200 Hz) are mounted in the upper half of the seatback 12 while the vibrating devices corresponding to the low frequency band (50 to 100 Hz) are mounted in the seat proper 13 is that the human body is sensitive to low-frequency vibrations applied from under the body.
In the above description, it should be noted that the number and the arrangement of the vibrating devices and the classification of the first mid-to-low frequency band, the second mid-to-low frequency band, and the low frequency band are only examples and may be changed appropriately to suit the shape and material of the seat, the shape of the vehicle compartment, etc.
Further, in the above description, three sound signals have been created by dividing the sound signal from the source 110 into three frequency bands, and the vibrating devices of the first to third vibrating device groups have been caused to vibrate simultaneously in accordance with the respective sound signals. Alternatively, control may be performed so that when the sound signal from the source 110 is rich in frequency components falling within the first mid-to-low frequency band (150 to 200 Hz), only the vibrating devices 160 and 161 of the first vibrating device group are caused to vibrate, but when the sound signal is rich in frequency components falling within the second mid-to-low frequency band (100 to 150 Hz), only the vibrating devices 162 and 163 of the second vibrating device group are caused to vibrate, while on the other hand, when the sound signal is rich in frequency components falling within the low frequency band (50 to 100 Hz), only the vibrating devices 164 to 169 of the third vibrating device group are caused to vibrate. Control for the above mode switching is performed by the band dividing circuit 40.
Further, a selector switch for allowing the occupant to select which of the first to third vibrating device groups is to be caused to vibrate may be provided on or near the seat 10 so that the mode switching by the band dividing circuit 40 can be controlled in accordance with the setting of the selector switch.
FIG. 5 is a diagram showing another mounting example of the vibrating devices.
In the example of FIG. 5, two vibrating devices 170 and 171 are mounted only in the center portion of the seatback 12 of the seat 10 by arranging the vibrating devices along a direction perpendicular to the longitudinal direction of the seatback 12. In this case also, the vibrating devices 170 and 171 are mounted to avoid positions that directly contact the occupant's back when the occupant is seated in the seat 10. Further, since each of the vibrating devices 170 and 171 is mounted so that the direction of its vibration is parallel or substantially parallel to the occupant-side surface of the seatback 12, the vibration can be transmitted indirectly to the occupant, reducing the possibility of giving the occupant an uncomfortable feeling or a sensation of pressure even when the system is used for an extended period of time.
In the case of FIG. 5, the vibrating devices 170 and 171 are driven by the sound signal representing the entire frequency range (200 to 50 Hz)
FIG. 6 is a diagram showing still another mounting example of the vibrating devices.
In the example of FIG. 6, two vibrating devices 180 and 181 are mounted only in the center portion of the seatback of the seat 10 by arranging the vibrating devices along a direction parallel to the longitudinal direction of the seatback 12. In this case, the vibrating devices 180 and 181 are mounted to avoid positions that directly contact the occupant's back when the occupant is seated in the seat 10. Further, since each of the vibrating devices 180 and 181 is mounted so that the direction of its vibration is parallel or substantially parallel to the occupant-side surface of the seatback 12, the vibration can be transmitted indirectly to the occupant, reducing the possibility of giving the occupant an uncomfortable feeling or a sensation of pressure even when the system is used for an extended period of time.
In the case of FIG. 6, the vibrating devices 180 and 181 are driven by the sound signal representing the entire frequency range (200 to 50 Hz).

Claims

1. A vibro-acoustic system comprising:

a seat having a seatback and a seat proper; and

a vibrating device which vibrates in accordance with an applied sound signal,

wherein said vibrating device is mounted in said seat so that the direction of vibration of said vibrating device is parallel or substantially parallel to an occupant-side surface of said seatback or said seat proper.

2. The vibro-acoustic system according to claim 1, further comprising a source which produces said sound signal.

3. A vibro-acoustic system comprising:

a seat having a seatback and a seat proper;

a band dividing circuit which produces a first sound signal and a second sound signal by dividing an input sound signal into frequency bands;

a first vibrating device which vibrates in accordance with said first sound signal, and which is mounted in said seatback so that the direction of vibration of said first vibrating device is parallel or substantially parallel to an occupant-side surface of said seatback; and

a second vibrating device which vibrates in accordance with said second sound signal, and which is mounted in said seat proper so that the direction of vibration of said second vibrating device is parallel or substantially parallel to an occupant-side surface of said seat proper.

4. The vibro-acoustic system according to claim 3, further comprising a source which produces said sound signal.

5. The vibro-acoustic system according to claim 3, wherein said first sound signal is higher in frequency than said second sound signal.

6. The vibro-acoustic system according to claim 3, wherein said seatback and said seat proper are each formed from a polyurethane foam, and said first and second vibrating devices are mounted so as to be embedded in the respective polyurethane foams.

7. The vibro-acoustic system according to claim 3, further comprising a selecting means for selecting which of the first and second vibrating devices is to be caused to vibrate.