Acoustics – Sound-modifying means – Sound absorbing panels
Reexamination Certificate
2002-01-17
2004-03-09
Nappi, Robert (Department: 2837)
Acoustics
Sound-modifying means
Sound absorbing panels
C181S284000
Reexamination Certificate
active
06702063
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a surface material disposed on a surface of a body receiving a vibration and a method for suppressing influence due to a surface wave generated on the surface of the body by a vibration.
BACKGROUND OF THE INVENTION
In a vibration transmittable member, although a given vibration propagates into an interior of the member mainly as a longitudinal vibration (namely, a stretching vibration in a direction of the progress of the vibration) depending on the Young's modulus in the region having a size corresponding to the amplitude, in all substances a transverse vibration (namely, a stretching vibration in a direction perpendicular to the direction of the progress of the vibration) also generates depending on the modulus of transverse elasticity. This transverse vibration becomes a surface wave (namely, a concave/convex surface wave such as a surface wave of water). In the surface wave, because not only there is a stationary phase lag but also there occur modulation distortion and phase distortion depending on the microscopic form and crystalline condition of the member surface, it becomes a great inflection point on mechanical impedance, and most of the surface wave re-propagates into the interior of the member. This causes a great influence in precision instruments and acoustic equipments.
In consideration of acoustic reflection and absorption surfaces defining an acoustic space, in a reflection surface, when an acoustic wave hits the surface, an adiabatic compression occurs and subsequently an adiabatic expansion occurs, and the acoustic wave turns as if a light reflects from a mirror. However, because there is no complete rigid material in practice, the energy of the acoustic wave is once converted into a vibration of the member, and further, a part thereof becomes a thermal energy and the remaining part reflects receiving a modulation due to an intrinsic property of the member. Therefore, even if the reflectances of the acoustic energy are the same, the waveforms of the reflected acoustic waves are different from each other depending upon the surface conditions of the members. Namely, the tone of the reflected sound varies by the above-described non-stationary noise originating from the surface wave.
Moreover, in an acoustic absorption m ember, because the conversion into a thermal energy is great as well as the modulation due to the intrinsic property of the member is remarkably great, even if the absolute amount of the reflectance is small, the tone is greatly influenced more than in a reflection surface. In other words, a peculiarity is likely to appear in a soft acoustic absorption surface much more than in a hard acoustic reflection surface.
In the conventional technology, although sound absorbing acoustic materials such as a rock wool, a glass wool and a worsted felt have been used, even if the purpose for absorbing sound can be achieved as a stationary property, there may occur an acoustic component uncomfortable on acoustic sense, such as non-stationary noise having a high frequency.
For example, in a theater hall or a concert hall, the above-described acoustic materials are partially used by a single or composite formation in order to control the acoustic property of the inside of the hall. Further, similar acoustic materials also are used for chairs disposed in the hall in order to control the acoustic property of the hall. When such conventional acoustic materials are used, however, the tone on acoustic sense indicates a distortional feeling and a turbid feeling, and it is not preferable.
As described hereinabove, the distortional feeling or the turbid feeling due to the non-stationary noise originating from the surface wave influences not only the acoustic materials but also all materials transmitting vibration. For example, even in equipments handling images, the surface wave of a base material forming an equipment greatly influences the obtained image quality.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a surface material which can suppress an influence due to a surface wave generated on a surface of a body by a vibration, which can prevent deterioration of a sound quality or can obtain a clearer image quality by suppressing generation of non-stationary noise having a high frequency uncomfortable to a man, and a method for suppressing an influence due to a surface wave by using the surface material.
To accomplish the above object, a surface material according to the present invention comprises a fibrous structure having a weight average single fiber thickness of from 0.0001 to 1 dtex, a thickness of from 0.10 to 5 mm and a unit weight of from 50 to 500 g/m
2
, and the surface material is disposed on a surface of a body to convert at least a part of a surface wave generated on the surface of the body by a vibration of the body into a vibration of the fibrous structure.
Further, a surface material according to the present invention comprises a fibrous structure which is formed by a group of extra fine fibers having a weight average single fiber thickness of from 0.0001 to 1 dtex, a Young's modulus of not more than 210 GPa and a fiber density of from 0.10 to 0.50 g/cm
3
and in which respective extra fine fibers exist at a condition capable of being vibrated relative to each other by a vibration energy, and the surface material is disposed on a surface of a body to convert at least a part of a surface wave generated on the surface of the body by a vibration of the body into a vibration of the fibrous structure.
A method for suppressing influence due to a surface wave according to the present invention comprises the steps of disposing a fibrous structure on a surface of a body, the fibrous structure having a weight average single fiber thickness of from 0.0001 to 1 dtex, a thickness of from 0.10 to 5 mn and a unit weight of from 50 to 500 g/m
2
; and converting at least a part of a surface wave generated on the surface of the body by a vibration of the body into a vibration of the fibrous structure.
Further, a method for suppressing influence due to a surface wave according to the present invention comprises the steps of disposing a fibrous structure on a surface of a body, the fibrous structure being formed by a group of extra fine fibers having a weight average single fiber thickness of from 0.0001 to 1 dtex, a Young's modulus of not more than 210 GPa and a fiber density of from 0.10 to 0.5 g/cm
3
and respective extra fine fibers existing at a condition capable of being vibrated relative to each other by a vibration energy; and converting at least a part of a surface wave generated on the surface of the body by a vibration of the body into a vibration of the fibrous structure.
In the surface material and the method for suppressing influence due to a surface wave according to the present invention, at least a part of the surface wave, which is a transverse vibration caused on the surface of the body by the vibration of the body, is converted into a vibration of the specified fibrous structure which is disposed on the surface of the body. In the interior of this specified fibrous structure, it is not performed that a member itself vibrates integrally, thereby absorbing or damping a transmitted vibration, but the respective fibers forming the fibrous structure mutually vibrate, thereby removing or suppressing the undesirable non-stationary noise component such as a high frequency component from the reflected vibration component and the re-propagated vibration component into the member. Therefore, by using the acoustic member or the member for handling image on which the surface material is disposed, distortional feeling and turbid feeling of the tone of the sound originating from the surface wave can be suppressed, or unclear feeling and unnatural feeling of the image quality can be suppressed, and vivid sound quality without turbid feeling or image quality with clear and natural color tone can be obtained.
THE BEST MODE FOR CARRYING OUT THE INVENTION
The s
Maekawa Masaki
Tanabe Mitsuru
Tone Hiroyuki
Yamaguchi Toru
AICA Engineering Co. Ltd.
Warren David
LandOfFree
Surface material and method of suppressing influence of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Surface material and method of suppressing influence of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Surface material and method of suppressing influence of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3219434