Invisible sound barrier
AssigneeToyota Motor Engineering & Manufacturing North America, Inc.
InventorsTaehwa Lee, Hideo Iizuka
Life of this patent
Estimating the term…
Abstract
An invisible sound barrier includes a periodic array of spaced apart, columnar unit cells. Each unit cell includes a pair of joined, and inverted, columnar Helmholtz resonators, having neck portions that point in opposite directions. Each of the Helmholtz resonators can be formed of a sound absorbing material and coated with a light reflective material causing light to reflect around the resonators, thereby conferring invisibility. Each of the Helmholtz resonators can alternatively be formed of a light reflecting material, and positioned in between vertical mirrors, with a transparent material filling space between the resonators and the vertical mirrors.
Claims17
An invisible sound barrier comprising a one-dimensional periodic array of unit cells spaced apart by a lateral midpoint-to-midpoint distance P, each unit cell having a maximum lateral dimension W, wherein P is greater than W, and each unit cell comprising:
- a first Helmholtz resonator having:
- a hollow columnar structure formed of a solid sound reflecting material and having a cross-sectional shape defining an equilateral parallelogram with an outer dimension and a first internal chamber portion of a first volume;
- and
- a first neck forming an opening on a first side of the first Helmholtz resonator and placing the first internal chamber portion in fluid communication with an ambient environment;
- and
- a second Helmholtz resonator having:
- a hollow columnar structure formed of a solid sound reflecting material and having a cross-sectional shape defining an equilateral parallelogram with an outer dimension identical to that of the first Helmholtz resonator and a second internal chamber portion of a volume greater than the first volume;
- and
- a second neck, forming an opening on a second side of the second Helmholtz resonator that is opposite the first side of the first Helmholtz resonator, and placing the second internal chamber portion in fluid communication with the ambient environment;
- and
- a light reflecting material coating outer surfaces of the first and second Helmholtz resonators.
An invisible sound barrier comprising a one-dimensional periodic array of unit cells spaced apart by a lateral midpoint-to-midpoint distance P, each unit cell having a maximum lateral dimension W, wherein P is greater than or equal to W, and each unit cell comprising:
- a first Helmholtz resonator having:
- a hollow columnar structure formed of a solid light reflecting material and having a cross-sectional shape defining an equilateral parallelogram with an outer dimension and a first internal chamber portion of a first volume;
- and
- a first neck forming an opening on a first side of the first Helmholtz resonator and placing the first internal chamber portion in fluid communication with an ambient environment;
- and
- a second Helmholtz resonator having:
- a hollow columnar structure formed of a solid light reflecting material and having a cross-sectional shape defining an equilateral parallelogram with an outer dimension identical to that of the first Helmholtz resonator and a second internal chamber portion of a volume greater than the first volume;
- and
- a second neck, forming an opening on a second side of the second Helmholtz resonator that is opposite the first side of the first Helmholtz resonator, and placing the second internal chamber portion in fluid communication with the ambient environment;
- and
- first and second planar mirrors spaced laterally apart from the first and second Helmholtz resonators in a direction of periodicity of the one-dimensional periodic array;
- and
- a solid material, transparent to light, filling a volume between:
- the first and second Helmholtz resonators;
- and
- the first and second planar mirrors.
A roadside sound barrier comprising:
- a one-dimensional periodic array of unit cells spaced apart by a lateral midpoint-to-midpoint distance P, each unit cell having a maximum lateral dimension W, wherein P is greater than W, and each unit cell comprising:
- a first Helmholtz resonator having:
- a hollow columnar structure formed of a solid sound reflecting material and having a cross-sectional shape defining an equilateral parallelogram with an outer dimension and a first internal chamber portion of a first volume;
- and
- a first neck forming an opening on a first side of the first Helmholtz resonator and placing the first internal chamber portion in fluid communication with an ambient environment;
- and
- a second Helmholtz resonator having:
- a hollow columnar structure formed of a solid sound reflecting material and having a cross-sectional shape defining an equilateral parallelogram with an outer dimension identical to that of the first Helmholtz resonator and a second internal chamber portion of a volume greater than the first volume;
- and
- a second neck, forming an opening on a second side of the second Helmholtz resonator that is opposite the first side of the first Helmholtz resonator, and placing the second internal chamber portion in fluid communication with the ambient environment;
- and
- a light reflecting material coating outer surfaces of the first and second Helmholtz resonators.
Dependencies are inferred from the claim text.