VIBRO-ACOUSTIC SYSTEM
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.
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 INVENTIONThe present invention relates to a vibro-acoustic system, or more specifically to a vibro-acoustic system for mounting in a vehicle seat.
BACKGROUND ARTA 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 INVENTIONAccordingly, 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.
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.
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.
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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.
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
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.
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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.
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Next, the operation of the vibro-acoustic system 100 will be described.
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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.
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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.
Type: Application
Filed: Nov 30, 2007
Publication Date: Jun 5, 2008
Inventor: Yuichi Nakajima (Kobe-shi)
Application Number: 11/948,974
International Classification: A47C 31/00 (20060101);