Abstract: A broadband ultrathin sound absorption or sound insulation structure controlling an acoustic wave propagation path has at least one sound absorption unit or one sound insulation unit; and each sound absorption unit or sound insulation unit has at least one acoustic wave focused section and at least one acoustic wave absorption section. The acoustic wave focused section is formed by an acoustic wave focused cavity filled with acoustic material. The acoustic wave focused section controls the acoustic wave propagation path through the change of a section of the cavity and the change of material equivalent parameters in the cavity, so that the acoustic waves are focused and propagate along the curve. The acoustic wave absorption section realizes efficient broadband sound absorption through the filled sound absorption materials and the arranged periodic local oscillators along an ultralong path of acoustic wave absorption labyrinth passage.

Abstract: A broadband ultrathin acoustic wave diffusion structure has a plurality of acoustic wave diffusion units. Each acoustic wave diffusion unit has at least one acoustic wave propagation section, and an acoustic wave focused section communicating with the acoustic wave propagation section is arranged according to needs. The acoustic wave focused section is formed by an acoustic wave focused cavity filled with acoustic material. The acoustic wave focused cavity is a variable-section cavity. The acoustic wave propagation section is formed by a simply connected acoustic wave propagation passage with a close end. Different acoustic wave diffusion units have different lengths of the simply connected acoustic wave propagation passages. The maximum length of the simply connected acoustic wave propagation passage may be dozens or even hundreds of times of the thickness of the acoustic wave diffusion structure, which can meet the diffusion requirements for low frequency acoustic waves to the maximum extent.

Abstract: A broadband ultrathin acoustic wave diffusion structure has a plurality of acoustic wave diffusion units. Each acoustic wave diffusion unit has at least one acoustic wave propagation section, and an acoustic wave focused section communicating with the acoustic wave propagation section is arranged according to needs. The acoustic wave focused section is formed by an acoustic wave focused cavity filled with acoustic material. The acoustic wave focused cavity is a variable-section cavity. The acoustic wave propagation section is formed by a simply connected acoustic wave propagation passage with a close end. Different acoustic wave diffusion units have different lengths of the simply connected acoustic wave propagation passages. The maximum length of the simply connected acoustic wave propagation passage may be dozens or even hundreds of times of the thickness of the acoustic wave diffusion structure, which can meet the diffusion requirements for low frequency acoustic waves to the maximum extent.

Abstract: A broadband ultrathin sound absorption or sound insulation structure controlling an acoustic wave propagation path has at least one sound absorption unit or one sound insulation unit; and each sound absorption unit or sound insulation unit has at least one acoustic wave focused section and at least one acoustic wave absorption section. The acoustic wave focused section is formed by an acoustic wave focused cavity filled with acoustic material. The acoustic wave focused section controls the acoustic wave propagation path through the change of a section of the cavity and the change of material equivalent parameters in the cavity, so that the acoustic waves are focused and propagate along the curve. The acoustic wave absorption section realizes efficient broadband sound absorption through the filled sound absorption materials and the arranged periodic local oscillators along an ultralong path of acoustic wave absorption labyrinth passage.

Abstract: The present invention discloses a ultrathin acoustic impedance converter belonging to the acoustic field, which is characterized by comprising one or a plurality of impedance conversion units, wherein each impedance conversion unit is composed of a frame, a plurality of prestressed membranes or prestressed string nets, and multiple layers of acoustic materials, wherein a through cavity is fabricated in the frame, the prestressed membranes or string nets and the acoustic materials are alternately arranged in the cavity, i.e., a prestressed membrane or string net is arranged, and then a layer of acoustic materials is arranged, and so on until the through cavity is fully filled. The cavity can be designed in different shapes either with a variable cross section or a uniform cross section.

Abstract: The present invention discloses a ultrathin acoustic impedance converter belonging to the acoustic field, which is characterized by comprising one or a plurality of impedance conversion units, wherein each impedance conversion unit is composed of a frame, a plurality of prestressed membranes or prestressed string nets, and multiple layers of acoustic material, wherein a permeable cavity is arranged in the frame, the prestressed membranes or string nets and the acoustic material are alternately arranged in the cavity, i.e., a prestressed membrane or string net is arranged, and then a layer of acoustic material is arranged, and so on until the cavity is fully filled. The cavity can be designed in different shapes, including a variable cross section and a uniform cross section. Each prestressed membrane or string net is required to be applied with prestress before being arranged in the cavity, and the magnitude of the prestress depends on the resistance value that the membrane or string net is expected to reach.