Electrical audio signal processing systems and devices – Electro-acoustic audio transducer – Electrostrictive – magnetostrictive – or piezoelectric
Reexamination Certificate
1998-12-16
2001-06-05
Le, Huyen (Department: 2643)
Electrical audio signal processing systems and devices
Electro-acoustic audio transducer
Electrostrictive, magnetostrictive, or piezoelectric
C381S340000, C381S430000
Reexamination Certificate
active
06243475
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a speaker and more particularly to a speaker which is efficient in the low sound range.
2. Description of Prior Art
A conventional speaker used for low sound range has a back load horn arranged such that a sound path is folded to reduce the size of the speaker.
However, the prior art speaker using the back load horn has a directivity because an opening of its sound path is directional.
Further, because the folded part of the sound path has a mere slit or chamfered structure in the prior art speaker using the back load horn, the flow of sound is disturbed at the folded part of the sound path. Therefore, in such a conventional speaker. it is hard to obtain plane waves and the sound is distorted.
SUMMARY OF THE INVENTION
To overcome the problems mentioned above, the preferred embodiments of the present invention provide a speaker which has a substantially reduced size, is efficient in a low sound range and transmits sound waves in all directions relative to a plane of a surface on which the speaker is mounted or supported. The preferred embodiments of the present invention provide a speaker having these features and advantages and also which substantially eliminates turbulence of sound flow.
A speaker according to a preferred embodiment of the present invention comprises a substantially semispherical vibrating body; a driving device for vibrating the vibrating body; and a horn having a sound path which is folded and extends from a curved inner surface of the vibrating body toward an outside of the speaker; wherein a cavity which communicates with the sound path is defined between the vibrating body and the horn and openings of the sound path are arranged such that sound waves are emitted from the openings toward a surface on which the speaker is supported in all directions relative to a plane of the speaker support surface. The horn preferably comprises a plurality of cylinders arranged in a multilevel arrangement having spaces defined between adjacent cylinders, the cylinders being centered around a central axis of the speaker. The sound path includes inner parts of the plurality of cylinders and the openings of the sound path are preferably disposed in an outermost cylinder of the plurality of cylinders. It is preferred if the openings in the sound path extend around an entire circumferential periphery of the speaker.
Thus, the novel structural arrangement resulting from the combination of the semispherical vibrating body and the horn and sound path described above provides a unique combined sound transmission. The unique combined sound transmission is achieved as a result of the semispherical vibrating body transmitting sound waves away from a speaker support surface in all directions relative to the speaker support surface while the unique arrangement of the horn and sound path results in sound waves being transmitted from the openings of the sound path toward the speaker support surface in all directions relative to the speaker support surface.
Another speaker according to the preferred embodiments of the present invention comprises a substantially semispherical vibrating body; a driving device for vibrating the vibrating body; and a horn having a sound path which is folded and extends from a curved inner surface of the vibrating body toward an outside of the speaker; wherein a cavity which communicates with the sound path is created between the vibrating body and the horn; openings of the sound path are arranged in the horn such that sound waves are emitted from the openings toward a surface on which the speaker is supported, in all directions relative to a plane of the speaker support surface; and the folded parts of the sound path and the openings of the sound path are arranged so as to expand from an inner portion to an outer portion of the sound path. It is noted that in the speaker, the horn preferably comprises a plurality of cylinders arranged in a multilevel arrangement having spaces defined between adjacent cylinders, the cylinders being centered about a central axis of the speaker. The sound path includes inner parts of the plurality of cylinders and the folded parts of the sound path preferably comprise substantially V-shaped cutouts formed in the plurality of cylinders and the openings of the sound path comprise substantially V-shaped cutouts formed in an outermost cylinder among the plurality of cylinders.
When an electrical signal is input, the vibrator is vibrated by the vibrating device, thus radiating sound waves from the curved outer surface of the vibrating body and from the curved inner surface of the vibrating body via the cavity and the sound path in the inventive speaker providing a unique combination of sound wave emanation and sound transmission.
Because the vibrating body has a substantially semispherical shape, the sound waves radiated from the curved outer surface of the vibrating body are radiated away from the speaker support surface in all directions relative to the speaker support surface. Further, because the openings of the sound path are arranged around substantially an entire circumference of the speaker, the sound waves radiated from the curved inner surface of the vibrator via the cavity and the sound path of the horn are radiated toward the speaker support surface in all directions relative to the plane of speaker support.
Further, for the inventive speaker, because the horn comprises the plurality of cylinders which are arranged in a multilevel arrangement while providing spaces therebetween and is centered around the central axis of the speaker and has the sound path which expands from the center thereof toward the outside, the speaker has a substantially reduced size despite the long sound path of the horn and the efficiency in the low sound range.
Further, in the preferred embodiments of the inventive speaker, because the folded parts and the openings of the sound path are created so as to expand from an inner portion to an outer portion of the sound path, the sound flows quickly at the portion where the distance of the sound path is longer, i.e. at the outer portion of the folded part of the sound path and the opening of the sound path, and the sound flows slowly at the portion of the sound path where the distance of the sound path is shorter, i.e. at the inner portion of the folded part of the sound path and the opening of the sound path. As a result, the speeds of the sound waves become almost equal at the outer portion and the inner portion of the folded parts and the opening of the sound path and the flow of sound is hardly disturbed at the folded parts and the openings of the sound path.
According to the preferred embodiments of the present invention, a speaker which is small, which is efficient in the low sound range and which generates sound waves which are transmitted in all directions relative to a speaker support surface or installation surface is provided.
Further, according to the preferred embodiments of the present invention, a speaker which is small, is efficient in the low sound range, is omni-directional relative to the speaker support and which hardly disturbs the flow of sound is obtained.
These and other elements, features, and advantages of the preferred embodiments of the present invention will be apparent from the following detailed description of the preferred embodiments of the present invention, as illustrated in the accompanying drawings.
REFERENCES:
patent: 4401911 (1983-08-01), Ravinet et al.
patent: 4440983 (1984-04-01), Facoetti et al.
patent: 4866683 (1989-09-01), Phillips
patent: 5185549 (1993-02-01), Sullivan
patent: 5802196 (1998-09-01), Nakamura
patent: 5896460 (1999-04-01), Nakamura et al.
patent: 560727 (1944-04-01), None
Heinouchi Yoshiaki
Nakamura Takeshi
Keating & Bennett LLP
Le Huyen
Murata Manufacturing Co. Ltd.
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