Patent Publication Number: US-2017370098-A1

Title: Acoustic Structure

Description:
TECHNICAL FIELD 
     The present invention relates generally to acoustic structures. 
     BACKGROUND ART 
     In rooms surrounded by walls, such as music halls, theaters and conference rooms, acoustic problems, such as booming and flutter echo, can sometimes occur due to sound repeatedly reflecting between parallel opposed wall surfaces. Patent Literature 1 identified below discloses an acoustic structure where a plurality of pipes each having a rectangular cross-sectional shape are arranged and an opening portion is formed in a side surface of each of such pipes in order to prevent the aforementioned acoustic problems. 
     Patent Literature 1: Japanese Patent Application Laid-open Publication No. 2010-084509 
     In the conventionally-known acoustic structure, wall members defining a hollow section that functions to produce an acoustic effect are each formed of an opaque material, such as wood or synthetic resin. Where the acoustic structure is installed in a room, a user may feel that the interior space of the room is narrow and some people may be given a cooped-up (or confined) feeling because the acoustic structure is considerably bulky, so that some people may be given a cooped-up feeling and thus the acoustic structure may not be capable of imparting a comfortable usability to the user. Namely, the conventionally-known acoustic structure is not designed in such a manner that, where it is installed in a room, it can impart a user (i.e., a person present in the room) with a comfortable usability. 
     SUMMARY OF INVENTION 
     In view of the foregoing prior art problems, it is an object of the present invention to provide an acoustic structure capable of achieving an enhanced usability. 
     In order to accomplish the aforementioned object, the present invention provides an improved acoustic structure, which comprises: at least one hollow section defined by a pair of transparent or translucent wall members disposed in opposed relation to each other and a plurality of connecting wall members interconnecting the pair of wall members; and an opening portion that communicates an interior space of the hollow section to an exterior space. 
     According to the present invention, of the wall members defining the hollow section that functions to produce an acoustic effect, the wall members disposed in opposed relation to each other is formed of a transparent or translucent material to provide a pair of transparent or translucent wall members, so that light can be directed from the back side of the acoustic structure, through the pair of transparent or translucent wall members, to the front side of the acoustic structure. Thus, in the case where the acoustic structure is installed in a room, the present invention can prevent a user from feeling that the interior space of the room is narrow due to the installed acoustic structure. Namely, the present invention can effectively reduce a cooped-up feeling of the interior space of the room where the acoustic structure is installed. Further, because light or a scene on the back side of the installed acoustic structure can be viewed from the front side of the acoustic structure, the user can feel an increased spatial extent, so that enhanced usability of the acoustic structure can be achieved. As a result, the acoustic structure of the present invention can have an enhanced outer appearance and aesthetic design. 
     In one embodiment of the present invention, at least part of the plurality of connecting wall members may be constructed to have a mirror surface. Thus, the user present on the front side of the acoustic structure can view not only light or a scene seen through the pair of transparent or translucent wall members but also light or a scene reflected from the mirror surface. In this manner, the user can feel a further increased spatial extent, so that even further enhanced usability of the acoustic structure can be achieved. As a result, the acoustic structure of the present invention can have an even further enhanced outer appearance and aesthetic design. 
     According to another aspect of the present invention, there is provided an improved acoustic structure, which comprises: at least one hollow section defined by a pair of transparent or translucent wall members disposed in opposed relation to each other and a plurality of connecting wall members interconnecting the pair of wall members; an opening portion that communicates an interior space of the hollow section to an exterior space; and mirror surfaces provided on such portions, inside and outside of wall surfaces defining the hollow section, that linear viewing through the pair of wall members is not prevented. Thus, in this case too, the user present on the front side of the acoustic structure can view not only light or a scene seen through the pair of transparent or translucent wall members but also light or a scene reflected from the mirror surface. In this way, the user can feel an even further increased spatial extent, so that even further enhanced usability of the acoustic structure can be achieved. As a result, the acoustic structure of the present invention can have an even further enhanced outer appearance and aesthetic design. 
     In one embodiment of the present invention, the acoustic structure may further comprise a lighting device disposed near the outside or the inside of the hollow section. Because the transparent or translucent wall members defining the hollow section are illuminated with the light emitted from the lighting device, the outer appearance and aesthetic design of the acoustic structure of the present invention can be enhanced even further. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a front view showing an acoustic structure according to an embodiment of the present invention. 
         FIG. 2  is a sectional view taken along the A-A line of  FIG. 1 . 
         FIG. 3  is a sectional view, similar to  FIG. 2 , showing a modification of the acoustic structure of  FIG. 1 . 
         FIG. 4  is a sectional view, also similar to  FIG. 2 , showing a modification of the acoustic structure of  FIG. 1 . 
         FIG. 5  is a sectional view, also similar to  FIG. 2 , showing still another modification of the acoustic structure of  FIG. 1 . 
         FIG. 6  is a front view showing an acoustic structure provided with mirror surface layers according to an embodiment of the present invention. 
         FIG. 7  is a sectional view taken along the B-B line of  FIG. 6 . 
         FIG. 8  is a sectional view, similar to  FIG. 7 , showing a modification of the acoustic structure of  FIG. 6 . 
         FIG. 9  is a sectional view, also similar to  FIG. 7 , showing another modification of the acoustic structure of  FIG. 6 . 
         FIG. 10  is a sectional view, also similar to  FIG. 7 , showing still another modification of the acoustic structure of  FIG. 6 . 
         FIG. 11  is a front view showing an acoustic structure provided with a lighting device according to an embodiment of the present invention; 
         FIG. 12  is a sectional view taken along the C-C line of  FIG. 11 . 
         FIG. 13  is a modification of the acoustic structure shown in  FIG. 11 , of which (a) is a fragmentary enlarged sectional view of the modification of the acoustic structure and (b) is an enlarged sectional view showing principal parts of the modification of the acoustic structure shown in (a) of  FIG. 13 . 
         FIG. 14  is another modification of the acoustic structure shown in  FIG. 11 , of which (a) is a fragmentary enlarged sectional view of the modification of the acoustic structure and (b) is an enlarged sectional view showing principal parts of the modification shown in (a) of  FIG. 14 . 
         FIG. 15  is a fragmentary enlarged sectional view of still another modification of the acoustic structure shown in  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION 
     First of all, a description will be given about an embodiment of the present invention with reference to  FIGS. 1 and 2 . As shown in  FIGS. 1 and 2 , an acoustic structure according to the embodiment includes a plurality of (four in the illustrated example) hollow sections  2  sequentially arranged parallel in a Y direction. Each of the hollow sections  2  is defined by a pair of transparent or translucent wall members  11  opposed to each other in an X direction and a plurality of connecting wall members  12  and  13  interconnecting the pair of wall members  11 , and each of the hollow sections has a vertically elongated shape in the illustrated example. More specifically, front and back surface walls of the hollow section  2  are formed by the pair of transparent or translucent wall members  11 , left and right side surface walls of the hollow section  2  are formed by a pair of left and right connecting wall members (also referred to as “side surface members”)  12 , and upper and lower (or bottom) surface walls of the hollow section  2  are formed by a pair of upper and lower connecting wall members (also referred to as “end surface members”)  13 . In the illustrated example, where the hollow sections  2  are formed integrally, the side surface members  12  are shared between adjoining ones of the hollow sections  2 , the wall member  11  constituting the front surface walls of the individual hollow sections  2  is a single large common panel, and the wall member  11  constituting the back surface walls of the individual hollow sections  2  is also a single large common panel. Further, the end surface member  13  constituting the upper surface walls of the individual hollow sections  2  is also a single plate member, and the end surface member  13  constituting the bottom surface walls of the individual hollow sections  2  is also a single common plate member. 
     Further, in each of the hollow sections  2 , at least one opening portion  3  is formed or provided in a given region of any one of the wall surfaces defining the hollow section  2 . In the illustrated example, one such opening portion  3  is provided in the wall member  11  constituting the front surface wall of the hollow section  2 , so that an exterior space outside of the acoustic structure  1  is communicated with an interior space of the hollow section  2  via the opening portion  3 . In this manner, the construction pertaining to each of the hollow sections  2  constitutes one Helmholtz resonator by means of the interior space of the hollow section  2  and a neck space intercommunicating the interior and exterior spaces via the opening portion  3 , thereby contributing to sound scattering and absorbing effects in an interior space of a room where the acoustic structure  1  is installed. As known in the art, the number of the opening portion  3  to be provided in association with each of the hollow sections  2  is not limited to just one and may be two or more. Further, the shape and size of the opening portion  3  is not limited to those of the illustrated example and may be modified as appropriate. For example, the opening portion  3  may be formed as a neck projecting outward beyond the outer surface of the wall member  11 . Furthermore, the opening portion  3  may comprise a single opening hole as shown in  FIG. 1  or a group of a plurality of small-diameter opening holes arranged close to each other in a predetermined region. In the latter case, it is only necessary that the group of opening holes constituting the opening portion  3  be provided in such a manner that the total area of the opening holes equals the area of the aforementioned single opening hole constituting the opening portion  3 . 
     The pair of wall members  11  constituting the front and back surface walls of the hollow section  2  is formed of a transparent material, such as glass or acrylic resin. As an example, the pair of wall members  11  is formed in its entirety of a colorless transparent material. As another example, the pair of wall members  11  may be formed in part of a colorless transparent material. As still another example, the pair of wall members  11  may be formed of an appropriately colored transparent material. 
     It suffices that the pair of wall members  11  be formed in such a manner that a scene or situations on the back side of the acoustic structure  1  can be viewed through the pair of wall members  11  at least from the front side of the acoustic structure  1 . Thus, a plurality of minute reflecting elements (not shown) may be provided dispersedly inside or on the surfaces of the wall members  11  only to the extent that viewing of the scene or situations on the back side of the acoustic structure  1  through the wall members  11  is not disturbed. The minute reflecting members may each be formed in any desired outer shape, such as a grain or foil shape. As another example, the pair of wall members  11  may be formed of a translucent material and colored appropriately in such a manner as to permit passage or transmission therethrough of desired light. In short, it just suffices that at least part of the pair of wall members  11  is configured to have colorless or colored transparency or translucence. 
     Note that the above-mentioned X direction is a direction substantially perpendicularly intersecting the above-mentioned Y direction. Namely, the direction in which the wall members  11  are opposed to each other with each of the hollow sections  2  interposed therebetween is substantially perpendicular to the parallel arranged direction Y of the hollow sections  2 . Thus, the transparent or translucent wall members  11  are opposed to each other in such a direction that the parallel arranged hollow sections  2  do not overlap one another, so that the acoustic structure  1  including the plurality of hollow sections  2 , as a whole, can be readily seen through via the transparent or translucent wall members  11 . 
     Further, the pair of side surface members (connecting wall members)  12  constituting the left and right side surface walls of the hollow section  2  may be formed, for example, of a colored transparent material, such as colored glass or acrylic resin, as shown in  FIG. 2 , or a translucent material that permits passage or transmission therethrough of light but cannot be seen through. In this case, the above-mentioned colored transparent material forming the pair of side surface members  12  may be of any desired color tone rather than limited to a particular color tone. The above-mentioned translucent material is a material that reflects light on its surface or in its interior without allowing the light to linearly pass therethrough. The above-mentioned translucent members may be of any desired specific construction; for example, the translucent members may be constructed by forming minute scratches in the surface of glass or acrylic resin, or by providing minute irregularly-light-reflecting elements within or on the surface of glass or acrylic resin. Further, a plurality of minute reflecting elements may be provided dispersedly inside or on the surfaces of the side surface members  12  in a similar manner to the aforementioned. The pair of side surface members  12  may be transparent or translucent in its entirety or part. As another example, the pair of side surface members (connecting wall members)  12  constituting the left and right side surface walls of the hollow section  2  may be formed of an opaque material that does not at all permit passage therethrough of light. 
     Further, in the instant embodiment, the pair of end surface members (connecting members)  13  may be formed in its entirety or in part of a colored transparent material or a translucent material, similarly to the aforementioned pair of side surface members  12 . Furthermore, a plurality of minute reflecting elements may be provided dispersedly inside or on the surfaces of the end surface members  13 , similarly to the aforementioned. As another example, the pair of end surface members  13  may be formed of an opaque material that does not at all permit passage therethrough of light. 
     Although the connecting wall members  12  and the connecting wall members  13  may be formed of a colored transparent material or a translucent material, the connecting wall members  12  or the connecting wall members  13  may be formed of a colored transparent material with the other connecting walls  13  or  12  formed of a translucent material. Further, in the case where the connecting wall members  12  and  13  are formed of a colored transparent material, they may be either identical to each other in color tone or different from each other in color tone. Thus, in a possible specific working example of the present invention, all the wall surfaces, rather than only the pair of wall members  11 , may be formed of a colorless or colored transparent or translucent material. 
     In the instant embodiment, each of the hollow sections  2  is formed in a cylindrical shape having a rectangular cross-sectional shape, and thus, the pair of wall members  11  and the pair of side surface members  12  constituting the wall surfaces of the hollow section  2  are each formed in a flat plate shape. However, the present invention is not so limited, and the pair of wall members  11  and/or the pair of side surface members  12  (and the end surface members  13  as necessary) may be formed present appropriately curved surface shapes so that a curved interior space (or near-circular cylindrical interior space) is formed within the hollow section  2 . As another example, in at least one of the hollow sections  2 , the two wall members  11  may be opposed to each other in a non-parallel fashion although they are each formed in a flat plate shape. 
     Further, in the illustrated example, the two wall members  11  are each constructed using a common panel shared among the plurality of hollow sections  2  and each extend substantially flush (in generally the same plane) between and over adjoining ones of the hollow sections  2 . In this way, each of the wall members  11  can be advantageously constructed with ease using a common panel shared among the plurality of hollow sections  2 . However, the present invention is not so limited, and at least one of the wall members  11  may be constructed to extend substantially flush between and over at least two adjoining ones of the hollow sections  2 . Alternatively, one surface of at least one of the two wall members  11  may be formed to have a stepped part, consisting of steps (level difference), between at least two adjoining ones of the hollow sections  2 . 
       FIG. 3  is a sectional view showing a modification of the acoustic structure which is constructed to define a stepped part, consisting of steps, between at least two adjoining ones of the hollow sections  2 . With such a stepped part, it is possible to construct the acoustic structure  1  such that the adjoining hollow sections  2  differ from each other in depth as appropriate. In this case, at least portions  12   b ,  12   c  and  12   d  of the side surface member (connecting wall member)  12  interconnecting steps of the two adjoining hollow sections  2  may have colorless or colored transparency or translucence. Because the portions  12   b ,  12   c  and  12   d  of the side surface member (connecting wall member)  12  projecting outward to define the stepped part have colorless or colored transparency or translucence similarly to the pair of wall members  11 , the acoustic structure  1  including the plurality of hollow sections  2  can, as a whole, achieve an even further enhanced see-through capability in a direction from the back surface or the vicinity of the back surface to the front surface, despite such a modified construction. 
     Further, the pair of wall members  11  and the pair of side surface members  12 , defining the wall surfaces of each of the hollow sections  2 , are formed separately from each other and then fixed to each other in the instant embodiment, although they may be integrally formed together, for example, of synthetic resin. Further, the pair of wall members  11  and the pair of side surface members  12  are fixed to each other by an adhesive in the instant embodiment, although they may be fixed to each other by screws or the like. It is preferable that the adhesive to be used for fixing the pair of wall members  11  and the pair of side surface members  12  to each other have light permeability. For example, the adhesive may be conventionally-known synthetic resin or a solvent that temporarily dissolves the transparent material forming the hollow section  2 . 
     In the case where the pair of wall members  11  and the pair of side surface members  12  are to be fixed to each other by an adhesive, relative positions among the four members may be chosen as desired. For example, the pair of side surface members  12  is positioned between the wall members  11  spaced from each other in the plate thickness direction (X direction) in the instant embodiment (see  FIG. 2 ), although the pair of wall members  11  may be positioned between the side surface members  12  spaced from each other in the plate thickness direction (Y direction). Further, in the instant embodiment, each of the end surface members  13  is positioned between the wall members  11  similarly to the side surface members  12 . 
     Further, the instant embodiment of the acoustic structure  1  includes the plurality of hollow sections  2 , as set forth above. The hollow sections  2  are identical to one another in length and thickness in the instant embodiment, although they may differ from one another in length and thickness. Furthermore, in the instant embodiment, the opening portions  3  are formed in positions differing among the hollow sections  2  with respect to the longitudinal direction of the hollow sections  2 . In the instant embodiment, the hollow sections  2  are arranged in the Y direction with no gap therebetween. In this manner, the acoustic structure  1  is formed in a panel shape with its dimension in the X direction constituting the thickness of the panel. The hollow sections  2  are formed integrally in the instant embodiment, although they may be formed separately and then fixed to one another. Needless to say, the acoustic structure  1  may include only one hollow section  2 . 
     The acoustic structure  1  constructed in the aforementioned manner may, for example, incorporated in a wall of a room, although it may be simply installed in a room. Further, the acoustic structure  1  may, for example, constitute a partitioning plate that partitions a room into a plurality of spaces. Furthermore, the acoustic structure  1  may, for example, be installed near a window or may, for example, constitute a window. 
     According to the instant embodiment of the acoustic structure  1 , as set forth above, light can be directed from the opposite side (back side) of the acoustic structure  1 , through the pair of transparent or translucent wall members  11 , to the front side of the acoustic structure  1 . In this way, it is possible to prevent the interior space of the room from being felt to be small even where the acoustic structure  1  is installed in the room; that is, it is possible to minimize a cooped-up (or confined) feeling that would be given by the interior space of the room where the acoustic structure  1  is installed. As a result, it is possible to achieve an enhanced outer appearance and aesthetic design of the acoustic structure  1 . 
     Further, according to the instant embodiment of the acoustic structure  1 , a scene or situations on the opposite side (back side) can be viewed, or light on the opposite side (back side) can be felt, from the front side through the transparent or translucent wall members  11  constituting the front and back surface walls of the acoustic structure  1 . Furthermore, in the case where the wall members  11  constituting the front and back surface walls of the acoustic structure  1  are made colorless transparent and the connecting wall members  12  and  13  are made colored transparent or translucent as noted above, boundaries between the wall members  11  and the connecting wall members  12  and  13  can be made unnoticeable. Such boundaries are adhesively attached parts between the wall members  11  and the connecting wall members  12  and  13  which are visible from the outside through the front wall member  11 , but even where the adhesively attached parts have air bubbles mixed therein, these air bubbles would be made unnoticeable. As a result, the acoustic structure  1  can have an even further enhanced outer appearance and aesthetic design. 
     Whereas one embodiment of the present invention has been described above in detail, it should be appreciated that the present invention is not limited to the above-described embodiment and may be modified variously without departing from the basic principles and sprit of the present invention. 
     For example, the pair of wall members  11  constituting the front and back surface walls may be formed of a colored transparent material as shown, for example, in  FIGS. 4 and 5 . In such a case, the left and right side surface members  12  may be formed as colorless transparent members as shown, for example, in  FIG. 4 , as translucent members as shown, for example, in  FIG. 5 , or as colored transparent members. Further, the upper and lower end surface members  13  may be formed as colorless transparent members, translucent members or colored transparent members, similarly to the left and right side surface members  12 . Such modified arrangements too achieve the same advantageous benefits as the above-described embodiment. 
     In the above-described construction, the color tone of the colored transparent material forming the pair of wall members  11  that constitutes the front and back surface walls may be of such a degree that a scene or situations on the back side of the pipe  2  can be viewed from the front side of the acoustic structure  1  through a pair of first wall portions  6 A. Further, in the case where the pair of wall members  11  constituting the front and back surface walls and the left and right side surface members  12  are each formed of a colored transparent material, these members  11  and  12  may be the same or different from each other in color tone. 
     Further, in all of the specific working examples described in this specification, the acoustic structure  1  may be modified in such a manner that the color tone of the colored transparent material forming the pair of wall members  11  and/or the connecting wall members  12  and  13  gradually varies, for example, in the longitudinal or transverse direction of the hollow sections  2 . Namely, the colored transparent material may be constructed to have a color tone gradation. As another modification, the acoustic structure  1  may be constructed in such a manner that the transparent or translucent color tone of the pair of wall members  11  gradually varies among the hollow sections  2  sequentially arranged in the transverse direction (Y direction). In these cases, the acoustic structure  1  can have an even further enhanced outer appearance and aesthetic design. Further, the translucent material forming the pair of wall members  11  and/or the connecting wall members  12  and  13  may have a color tone gradation similarly to the aforementioned colored transparent members. Note that the aforementioned feature that the color tone differs or varies not only means that generally the same hue differs or vary in lightness (light-and-dark or light-and-shade intensity), but also means that the hue itself differs or varies. 
     Next, with reference to  FIGS. 6 to 10 , a description will be given about several specific working examples of the acoustic structure  1  provided with mirror surface layers. In  FIGS. 6 to 10 , the same reference numerals as in  FIGS. 1 to 5  indicate the same constituent elements as in  FIGS. 1 to 5 , and these same constituent elements will not be described in detail here to avoid unnecessary duplication. 
     In  FIG. 6 , connected ends of the connecting wall members  12  and  13  to the wall member  11  in the form of a single transparent panel located frontmost are visible through such a frontmost transparent wall member  11 , and mirror surfaces  7 A and  7 B are provided on the above-mentioned connected ends of the connecting wall members  12  and  13 . 
     The following paragraphs first describe the mirror surfaces  7 A on the connecting wall members (side surface members)  12 . As shown in  FIG. 7 , the mirror surface  7 A on each of the side surface members  12  is the surface of a mirror surface layer  9  provided on a part of the surface of a base portion  8  defining the shape of the side surface member  12 . Namely, each of the side surface members  12  includes the base portion  8  and the mirror surface layer  9 . The base portion  8  in the instant embodiment is formed of a transparent material, such as glass or acrylic resin, similarly to the wall member  11 , although it may be formed, for example, of an opaque material that does not permit passage therethrough of light or a translucent material that permits passage therethrough of light but cannot be seen through. The mirror surface layer  9  may be formed, for example, by depositing metal on the surface of the base portion  8  or may be in the form of a member (e.g., a metal film member or a sheet member having metal deposited on a base sheet of paper or the like) attached to the surface of the base portion  8 . In the instant embodiment, the mirror surface layer  9  is provided on the surface of the base portion  8  facing in the X direction, and more specifically on the surface of the base portion  8  perpendicularly intersecting the X direction. Namely, in the instant embodiment, the mirror surface  7 A of the side surface member  12  perpendicularly intersects the X direction. In  FIG. 7 , the mirror surface  7 A is provided only on each of the connected ends of the side surface member  12  attached to the one wall member  11  (constituting the front surface wall). However, the present invention is not so limited, and the mirror surface  7 A may also be provided on each of the connected ends of the side surface member  12  attached to the other wall member  11  (constituting the back surface wall). 
     Next, the following describe the mirror surfaces  7 B on the connecting wall members (end surface members)  13 . As shown in  FIG. 6 , the mirror surface  7 B is provided on each of the connected ends of the upper and lower end surface members  13  to the front wall members  11 . Namely, like the aforementioned side surface members  12 , the end surface members  13  in the instant embodiment each include a base portion (not shown) defining the shape of the end surface member  13  and a mirror surface layer (not shown) provided on a part of the surface of the base portion, and the mirror surface layer constitutes the mirror surface  7 B. The base portion of the end surface member  13  is formed, for example, of a transparent material, such as glass or acrylic resin, in the instant embodiment, although it may be formed of an opaque or translucent material. Further, in the instant embodiment, the mirror surface  7 B of the end surface member  13  faces in the same direction as the mirror surface  7 A of the side surface member  12 , i.e. perpendicularly intersects the X direction. 
     The acoustic structure  1  shown in  FIGS. 6 and 7 , where the pair of wall members  11  etc. are transparent or translucent, allows a scene or situations on the opposite side (back side) to be viewed through such transparent or translucent portions, similarly to the aforementioned. In addition, because the mirror surfaces  7 A and  7 B are provided on portions of the surfaces of the connecting wall members (side surface members  12  and end surface members  13 ), scenes and situations around the acoustic structure  1  reflected on the mirror surfaces  7 A and  7 B can be viewed as necessary. Namely, because both a scene and situations on the opposite side of the acoustic structure  1  and scenes and situations reflected on the mirror surfaces  7 A and  7 B can be viewed, the acoustic structure  1  can have an even further enhanced outer appearance and aesthetic design. Besides, because both a scene and situations on the opposite side of the acoustic structure  1  and scenes and situations reflected on the mirror surfaces  7 A and  7 B can be viewed, it is possible to minimize a cooped-up (or confined) feeling of the interior space of the room where the acoustic structure  1  is installed. 
     Furthermore, in the instant embodiment of the acoustic structure  1 , the mirror surfaces  7 A and  7 B are provided on the connected parts of the individual connecting wall members (side surface members  12  and end surface members  13 ) to the pair of transparent or translucent wall members  11 . In this case, the transparency of the wall members  11  allows such connected parts (adhesively attached parts) of the individual connecting wall members to be viewed from the outside through the transparent wall members  11 . However, even where the adhesively attached parts have air bubbles mixed therein, the mirror surfaces  7 A and  7 B can make these air bubbles unnoticeable. As a result, the acoustic structure  1  can have an even further enhanced outer appearance and aesthetic design. 
     The parts on which the mirror surfaces are provided are not limited to the above-mentioned and may be modified as desired. For example, on the left and right side surface members  12 , the mirror surfaces  7 A may be provided on the surfaces facing the interior spaces of the hollow sections  2 , as shown in  FIG. 8 . Further, mirror surfaces  7 A′ may be provided on respective one outer surfaces of the outermost side surface members  12  constituting the outer surface of the acoustic structure  1 , as shown in  FIG. 8 . Further, although not particularly shown, the mirror surfaces  7 B too may be provided on the surfaces of the end surface members  13  facing the interior spaces of the hollow sections  2  in a similar manner to the above-mentioned. Also, the mirror surfaces  7 B may also be provided on the respective outer surfaces of the end surface members  13  constituting the outer surface of the acoustic structure  1 . Even with such arrangements, the acoustic structure  1  achieves the same advantageous benefits as the embodiment of  FIGS. 6 and 7 . 
     Further, in the case where the acoustic structure  1  illustratively shown in  FIG. 8  is installed near a window or constitutes a window, light (external light), such as sunlight, coming in from outside of the room, can be directed into the room after being reflected from the mirror surfaces  7 A of the side surface members  12 . In this way, a wider area of the interior of the room (e.g., the entire interior of the room) can be illuminated more lightly by the external light. 
     Further, the mirror surface  7 A may be formed on the entire surface of the side surface member  12  as shown in  FIG. 9 , rather than on only a particular part of the surface of the side surface member  12 . Furthermore, the mirror surface  7 B too may be formed on the entire surface of the end surface member  13 , rather than on only a particular part of the surface of the end surface member  13 , although not particularly shown in the drawings. 
     As another alternative, the mirror surface  7 A may be provide on a portion of the outer surface of the transparent or translucent wall member  11  that overlaps the side surface member  12  in the X direction as shown in  FIG. 10 , rather than provided directly on the surface of the side surface member  12 . Further, although not particularly shown in the drawings, the mirror surface  7 B too may be provide on a portion of the outer surface of the transparent or translucent wall member  11  that overlaps the end surface member  13  in the X direction. In short, the mirror surfaces  7 A and  7 B may be formed or provided on portions, outside of wall surfaces of the hollow section  2  defined by the pair of wall members  11 , that overlap the respective disposed positions of the connecting wall members  12  and  13  interconnecting the pair of wall members  11 . 
     Such arrangements too achieve the same advantageous benefits as the above-described embodiment of  FIGS. 6 and 7 . Further, the connected parts (adhesively attached parts) of the connecting wall members  12  and  13  to the wall members  11  are covered with the mirror surfaces  7 A and  7 B from outside as set forth above, and thus, even if the outer appearance and aesthetic design of the connected parts (adhesively attached parts) is adversely influenced, for example, due to mixing of air bubbles in the connected parts (adhesively attached parts), the connected parts (adhesively attached parts) can be prevented by the mirror surfaces from being viewed from outside, with the result that the acoustic structure  1  can have an even further enhanced outer appearance and aesthetic design. 
     Now, summarizing the embodiments illustratively shown in  FIGS. 6 to 10 , the acoustic structure  1  includes: at least one hollow section  2  defined by a pair of opposed transparent or translucent wall members  11  and a plurality of connecting wall members  12  and  13  interconnecting the pair of opposed wall members  11 ; an opening portion  2  communicating the interior space of the hollow section  2  with the exterior space; and mirror surfaces  7 A and  7 B provided on such portions, inside and outside of the wall surfaces constituting the hollow section  2 , that linear viewing through the pair of opposed wall members  11  is not prevented. 
     Next, with reference to  FIGS. 11 to 15 , a description will be given about several specific working examples of the acoustic structure  1  provided with a lighting device. In  FIGS. 11 to 15 , the same reference numerals as in  FIGS. 1 to 5  indicate the same constituent elements as in  FIGS. 1 to 5 , and these same constituent elements will not be described in detail here to avoid unnecessary duplication.  FIG. 12  is a sectional view taken along the C-C line of  FIG. 11 . Note that a sectional view taken along the A-A line of  FIG. 11  is substantially the same as  FIG. 2  and thus is not shown here. 
     As shown in  FIGS. 11 and 12 , the instant embodiment of the acoustic structure  1  includes, in addition to the constituent elements pertaining to at least any one of the above-described specific working examples, the lighting device  10  that irradiates light toward the hollow sections  2 . Note that, to achieve effective illumination, it is preferable that the wall members  11 ,  12  and  13 , constituting the hollow sections  2 , be formed, in their entirety or at least in their parts, of a transparent or translucent material. It is also preferable that, for efficient light irradiation, such transparent or translucent wall members have, on their parts near a light source, shielding layers or reflecting layers formed thereon as appropriate as will be described later. 
     The lighting device  10  in the instant embodiment may be constructed to emit light of various colors although it may alternatively be constructed to emit mere white light, and it may be constructed to be capable of adjusting the brightness of the light. Further, the lighting device  10  in the instant embodiment is formed in a bar shape and emits light in radial directions generally throughout the length thereof. Furthermore, the lighting device  10  in the instant embodiment may be in the form of a bar-shaped light source, such as a fluorescent lamp, or a plurality of dot-shaped light sources, such as LEDs, arranged in the longitudinal direction thereof. 
     Furthermore, the lighting device  10  is provided on respective one longitudinal end portions (upper end portions in  FIGS. 11 and 12 ) of the hollow sections  2 , although it may be provided on respective opposite longitudinal end portions of the hollow sections  2 . Here, the longitudinal direction of the lighting device  10  corresponds to the arranged direction of the plurality of hollow sections  2  (i.e., corresponds to the Y direction). Thus, the light emitted from the lighting device  10  is irradiated to each of the hollow sections  2  in the longitudinal direction of the hollow section  2  and passes through the interior space of the hollow section  2  in the longitudinal direction. 
     In the illustrated example of  FIGS. 11 and 12 , the lighting device  10  is placed on the end surface member  13  constituting the upper surface wall of the hollow sections  2 , and the end surface member  13  constituting the upper surface wall of the hollow sections  2  is formed of a transparent material. The acoustic structure  1  includes a mounting section  20  that detachably attaches the lighting device  10  to the hollow sections  2 . The mounting section  20  includes a retention section  21  that retains the lighting device  10 , and a sandwiching section  22  that is provided integrally with the retention section  21  for sandwiching the hollow sections  2 . The retention section  21  is formed in a box shape opening in one direction (i.e., downward). The lighting device  10  is accommodated in the retention section  21  in such a manner that it can be freely inserted into and out of the retention section  21 . The light is emitted from the lighting device  10  to the outside only through the opening of the retention section  21 . The inner surface of the retention section and/or the sandwiching section  22  may be formed as a mirror surface, although the mounting section  20  is not so limited. 
     The instant embodiment of the acoustic structure  1  further includes a signal output section  31 , and a light emission control section  32  that controls a lighting state of the lighting device  10  on the basis of a signal output from the signal output section  31 . The signal output section  31  includes a sensor section  33  for detecting an ambient temperature, humidity, light intensity and current time including any one of the seasons of the year, month, date, etc., and an input section  34  operable by a user of the acoustic structure  1  to manually input data of intensity and color of the light to be emitted by the lighting device  10 . 
     The light emission control section  32  varies the intensity and color of the light to be emitted by the lighting device  10  and switches between light-on and light-off (ON/OFF) states of the lighting device  10  on the basis of detection signals output from the sensor section  33  and data signals output from the input section  34 . Once the sensor section  33  detects that the ambient light intensity around the acoustic structure  1  is high or that it is now daytime, for example, the light emission control section  32  sets high the light to be emitted by the lighting device  10 . Further, once the sensor section  33  detects that the ambient light intensity around the acoustic structure  1  is low or that it is now winter time, for example, the light emission control section  32  sets the light to be emitted by the lighting device  10  at a warm color (e.g., red or orange color). 
     Further, once the sensor section  33  detects nightfall, for example, the light emission control section  32  lights or turns on the lighting device  10 . Once the sensor section  33  detects daybreak, on the other hand, the light emission control section  32  turns off the lighting device  10 . Further, once the sensor section  33  detects that it is a flag holiday or a day for a particular event today, for example, the light emission control section  32  repeats turning-on and turning-off of the lighting device  10  (i.e., flashes the lighting device  10 ) or changes as appropriate time intervals between the turning-on and turning-off of the lighting device  10 . 
     In the case where the acoustic structure  1  constructed in the aforementioned manner is to be installed in a room, such as a conference room, the acoustic structure  1  may, for example, be fixed to the wall surface of the room or placed on the floor surface of the room. Alternatively, the acoustic structure  1  may be hung down from the ceiling of the room via a hanging attachment  40 , such as a chain or a chord, as shown in  FIG. 11 . The hanging attachment  40  is connected to the mounting section  20  in the illustrated example of  FIG. 11 , although, alternatively, it may be connected for example to any of the wall members of the hollow sections  2 . 
     According to the instant embodiment of the acoustic structure  1 , where the hollow sections  2  formed of a transparent material are illuminated with the light emitted by the lighting device  10 , the hollow sections  2  can have an enhanced outer appearance and aesthetic design. Additionally, the hollow sections  2  can be shown gorgeously, for example, by the light of the lighting device  10  being refracted from the interfaces (boundary portions) between the wall members of the hollow sections  2  formed at least in part of a transparent or translucent material and the interior spaces of the hollow sections  2  or the exterior space. Further, even where the adhesively attached parts between the wall members (e.g., between the wall members  11  and the connecting wall members  12  and  13 ), constituting the hollow sections  2 , have air bubbles mixed therein, these air bubbles can be made unnoticeable, for example, by the light emitted by the lighting device  10  being refracted and reflected from the interfaces between the adhesively attached parts and the air bubbles. Further, the boundary portions between the members constituting the hollow sections  2  can be made unnoticeable, for example, by the light of the lighting device  10  being refracted from the boundary portions. In the aforementioned manner, it is possible to even further enhance the outer appearance and aesthetic design of the instant embodiment of the acoustic structure  1 . Moreover, with the lighting device  10  mounted to the wall members of the hollow section  2  formed of a transparent or translucent material, the acoustic structure  1  can be used also as lighting equipment. 
     Furthermore, according to the instant embodiment of the acoustic structure  1 , where the lighting device  10  is disposed on the respective one longitudinal end portions of the hollow sections  2  so that the light emitted by the lighting device  10  is irradiated to the hollow sections  2  in the longitudinal direction of the hollow sections  2 , it is possible to reduce the number of the interfaces between the interior spaces and wall portions of the hollow sections  2  through which the light emitted by the lighting device  10  passes. In this way, the light emitted by the lighting device  10  is allowed to easily pass from the one longitudinal end portion to the other of each of the hollow sections  2 , and thus, the light emitted by the lighting device  10  can be used efficiently to illuminate the interior of the room. The same advantageous benefits can also be achieved even in the case where the lighting devices  10  are disposed on the opposite longitudinal end portions of the hollow sections  2 . 
     Furthermore, according to the instant embodiment of the acoustic structure  1 , the lighting devices  10  is provided at a position adjoining the respective interior spaces and peripheral walls of the hollow sections  2  in the longitudinal direction of the hollow sections  2 . Thus, the light emitted by the lighting device  10  can be irradiated positively to the interior spaces of the hollow sections  2  and the interiors of the peripheral walls of the hollow sections  2 . Namely, the interior spaces of the hollow sections  2  and the interiors of the peripheral walls of the hollow sections  2  can be illuminated positively with the light emitted by the lighting device  10 . 
     Further, the instant embodiment of the acoustic structure  1  includes the signal output section  31 , and the light emission control section  32  that controls the lighting state of the lighting device  10  on the basis of a signal output from the signal output section  31 . Thus, with the instant embodiment of the acoustic structure  1 , it is possible to not only illuminate the hollow sections  2  with light of intensity and color suiting environments inside and outside of the room and preference of the user, but also switch between the light-ON and light-OFF states of the lighting device  10 . Such arrangements can also alleviate an uncomfortable feeling that would be caused by the acoustic structure  1  being installed in the room. 
     Moreover, the instant embodiment of the acoustic structure  1  includes the mounting section  20  that detachably attaches the lighting device  10  relative to the hollow sections  2 , so that the lighting device  10  can be readily replaced with respect to the hollow sections  2 . Furthermore, in the case where the inner surfaces of the retention section  21  and the sandwiching section  22  of the mounting section  20  have mirror surfaces formed thereon in the instant embodiment of the acoustic structure  1 , the light emitted by the lighting device  10  can be irradiated positively to the interior spaces of the hollow sections  2  and the interiors of the peripheral walls of the hollow sections  2  in the longitudinal direction of the hollow sections  2 . 
     Moreover, as a modification of the embodiment shown in  FIGS. 11 and 12 , a light shielding layer that does not permit passage therethrough of light or a mirror surface layer that reflects light may be provided on a portion of the inner wall surface of each of the hollow sections  2  in the acoustic structure  1 . The light shielding layer prevents transmission of light between the interior space of the hollow section  2  and the peripheral walls. The mirror surface layer reflects light passing in the interior space of the hollow section  2  and reflects light hitting the peripheral walls. In the above-described embodiments of the acoustic structure  1  where the plurality of hollow sections  2  are arranged in a row, such a light shielding layer or a mirror surface layer is formed preferably on each of the side surface members  12  of the peripheral walls, although it may be formed on each of the pair of wall members  11 . With such arrangements, the light emitted by the lighting device can be positively irradiated to the interior space of each of the hollow sections  2  and the peripheral walls in the longitudinal direction of the hollow sections  2 . 
     Furthermore, as shown for example in  FIGS. 13 and 14 , a lighting device  10 A may be provided in each of accommodating spaces  16  formed in the connecting wall members  12  or  13  constituting the hollow sections  12 . In this case, the accommodating space  16  accommodating each of the lighting devices  10 A may be in the form of a hollowed portion  15  that is hollowed from the surface of the wall portion connecting wall member  12  or  13  constituting the hollow section  2 . In the case where the accommodating space  16  is in the form of such a hollow, the acoustic structure  1  can be manufactured with ease. 
     In each of the acoustic structures  1 A and  1 B shown in  FIGS. 13 and 14 , the lighting device  10 A and the hollowed portions  15  (accommodating spaces  16 ) are provided on the respective one longitudinal end portions of the hollow sections  2 , as in the above-described embodiments. Note that each of the acoustic structures  1 A and  1 B shown in  FIGS. 13 and 14  is provided with a plurality of the lighting devices  10 A. 
     Further, in the acoustic structure  1 A shown in  FIG. 13 , the hollowed portions  15  are formed in the inner surface (surface)  13   a  of the end surface member  13  constituting the upper surface wall of each of the hollow sections  2 . Thus, the light emitted by each of the lighting devices  10 A provided in the hollowed portions  15  is irradiated to the interior space of the corresponding hollow section  2  in the longitudinal direction of the hollow section  2 . 
     Alternatively, in the acoustic structure  1 A shown in  FIG. 13 , the hollowed portions  15  may be formed as a single elongated groove extending in the arranged direction of the plurality of hollow sections  2 , and the lighting device  10 A may be provided in and along such an elongated hollowed portion  15 . In this case, the lighting device  10 A may be in the form of a bar-shaped light source extending in the arranged direction of the plurality of hollow sections  2 , as in the above-described embodiment. As another alternative, the lighting device  10 A shown in  FIG. 13  may be mounted to the inner surface  13   a  of the end surface member  13  of the hollow sections  2 , with no hollowed portion  15  formed. 
     In the acoustic structure  1 B shown in  FIG. 14 , on the other hand, the lighting device  10 A is provided in each of adhesively attached parts between the side surface members  12  and the end surface member  13 , and the side surface members  12  are formed of a transparent material. In this construction, the hollowed portions  15  are formed in the adhesively attached surfaces (surfaces)  12   a  of the side surface members  12  as illustrated in  FIG. 14 , although it may be formed in the end surface member  13 . In this manner, the light emitted by the lighting device  10 A provided in each of the hollowed portions  15  is irradiated through the transparent side surface member  12  to the hollowed portions  15  in the longitudinal direction of the hollowed portions  15 . 
     In the above-described acoustic structures  1 A and  1 B shown in  FIGS. 13 and 14 , a plurality of the lighting devices  10 A are provided so that the light emitted by these lighting devices  10 A separately illuminates the respective interior spaces and inner surfaces of the hollow sections  2 , i.e. different parts of the plurality of hollow sections  2 . The light emitted by these lighting devices  10 A can be made different from one another in color and intensity. In this way, it is possible to even further enhance the outer appearance and aesthetic design of the acoustic structures  1 A and  1 B. The plurality of the lighting devices  10 A may be provided, for example, in association with only one of the hollow sections  2 , rather than in association with the individual hollow sections  2 . In such a case, it just suffices that the plurality of the lighting devices  10 A be constructed to illuminate different parts of the one hollow section  2 . 
     Further, in the case where the accommodating space  16  for accommodating the lighting device  10 A is provided in the longitudinal end portion of the hollow section  2  as illustratively shown in  FIGS. 13 and 14 , a light shielding layer through which light does not transmit may be provided on a surface portion  16   a  of the inner surface of the accommodating space  16  that sandwiches the lighting device  10 A in conjunction with the wall member  12  extending in the longitudinal direction of the hollow section  2 . Further, similar light shielding layers may also be provided on inner side surface portions  16   b  (inner side surface portions  16   b  of the hollowed portion  15  in  FIGS. 12 and 13 ) of the inner surface that intersect the longitudinal direction of the hollow section  2 . Such arrangements can prevent the light emitted by the lighting device  10 A from leaking in unnecessary directions (i.e., in directions where the light does not illuminate the hollow sections  2 ). Namely, the light emitted by the lighting device  10 A can be positively irradiated to each of the hollow sections  2  in the longitudinal direction of the hollow section  2 . 
     Furthermore, mirror surface layers that reflect light may be provided on the surface portion  16   a  of the inner surface of the accommodating space  16  that sandwiches the lighting device  10 A in conjunction with the wall member  12  extending in the longitudinal direction of the hollow section  2  and on the inner side surface portions  16   b  (inner side surface portions  16   b  of the hollowed portion  15  in  FIGS. 13 and 14 ) of the inner surface of the accommodating space  16  that intersect the longitudinal direction of the hollow section  2 . With such arrangements, the light emitted by the lighting device  10 A can be positively irradiated to each of the hollow sections  2  in the longitudinal direction of the hollow section  2 . The aforementioned constructions shown in  FIGS. 13 and 14  may be combined as appropriate. 
     As still another alternative, the lighting device  10 A may be provided on the side surface member  12  formed of a transparent material, as shown for example in  FIG. 15 . In this case, the lighting device  10 A may, for example, be in the form of a bar-shaped light source extending in the longitudinal direction of the hollow section  2  (i.e., in a direction normal to the sheet of  FIG. 15 ) or a plurality of dot-shaped light sources arranged in the longitudinal direction of the hollow section  2 . In this construction, the lighting device  10 A is provided on or in the side surface member  12 , although it may be provided on or in the wall member  11 . More specifically, in the acoustic structure  1 C shown in  FIG. 15 , the lighting device  10 A is provided in the accommodating space  16  formed in the side surface member  12 , although it may be provided on the surface of the side surface member  12 . In such a case, the accommodating space  16  may be in the form of a hollowed portion  15  hollowed inward from the surface of the side surface member  12 , and the lighting device  10 A may be provided in the hollowed portion  15 . 
     The acoustic structure  1 C shown in  FIG. 15  achieves the same advantageous benefits as the acoustic structure  1 A shown in  FIG. 13 . Further, according to the acoustic structure  1 C shown in  FIG. 15 , both the interior space of the hollow section  2  and the interior of the wall member  12  can be illuminated with the light emitted by the same lighting device  10 A. 
     Further, in the case where two lighting devices  10 A are provided on the same side surface member  12 , constituting side surface walls of two adjoining hollow sections  2 , in the acoustic structure  1 C shown in  FIG. 15  so as to irradiate light to the respective interior spaces of the two adjoining hollow sections  2 , a light shielding layer which does not permit passage or transmission therethrough of light or a mirror surface layer which reflects light may be provided on the inner surface of each of the accommodating spaces  16  (hollowed portions  15 ). The construction illustratively shown in  FIG. 15  may be combined as appropriate with any of the constructions of the above-described embodiments and the constructions illustratively shown in  FIGS. 13 and 14 . 
     As a further modification, the aforementioned lighting device may be provided, for example, on only one end portion in the arranged direction of the plurality of hollow sections  2  (i.e., on only one end portion in the Y direction). In this modified construction, the light emitted by the lighting device may be irradiated in the arranged direction of the plurality of hollow sections  2  (i.e., in the Y direction) to pass through the plurality of hollow sections  2 . For example, the lighting device may be formed in a bar shape extending in the longitudinal direction of the hollow sections  2  as in the above-described embodiment, or a plurality of such lighting devices may be arranged in the longitudinal direction of the hollow sections  2 . Such modified constructions too achieve the same advantageous benefits as the above-described embodiments. Further, such lighting devices may be provided both on respective one longitudinal end portions of the hollow sections  2  and on one end portion in the arranged direction of the hollow sections  2 . The aforementioned construction may be combined as appropriate with any of the constructions of the above-described embodiments and the constructions illustratively shown in  FIGS. 13 to 15 .