KR20140066750A - Translucent sound-absorbing panel - Google Patents

Abstract

The present invention provides a translucent sound-absorbing panel capable of improving sound-absorbing properties and further improving translucency and transparency. An inner perforated plate (4) having a plurality of through holes (14) is arranged between the surface perforated plate (2) and the back surface sound insulating plate (3). The inner perforated plate 4 is made of a material having translucency and transparency such as resin and has a thickness of 0.2 mm or more and 1.5 mm or less.

Description

TRANSLUCENT SOUND-ABSORBING PANEL}

TECHNICAL FIELD [0001] The present invention relates to a light-permeable sound-absorbing panel having light transmittance and transparency and capable of reducing noise generated from roads, railways, factories, and the like.

A translucent sound-absorbing panel having transparency and transparency and capable of reducing noise generated from roads, railways, factories, etc. In Patent Document 1, a translucent sound-absorbing material, which is a film material having a plurality of holes, and a translucent sound- Discloses a translucent soundproof plate which is opposed to the light-permeable soundproof plate. Patent Document 2 discloses a light-transmissive film vibration-damping plate in which a transparent resin thin film is held between an aluminum expanded metal and a resin plate having a transparent hole formed therein.

Japanese Patent Application Laid-Open No. 2002-146727 Japanese Patent Application Laid-Open No. 2007-303080

However, in the light-transmitting sound insulating plate of Patent Document 1, since the translucent sound absorbing material which is a film material has low surface rigidity, the light-transmitting sound absorbing material vibrates with respect to the incident sound wave, Sound absorption performance is poor. Therefore, it is conceivable to reinforce the light-transmitting sound-absorbing material with expanded metal or the like, but the light transmittance and the visibility are lowered by the addition of the reinforcing material.

In addition, in the light-transmissive film vibration damping plate of Patent Document 2, the aluminum expanded metal for supporting the transparent resin thin film is deteriorated in transparency and transparency.

When a metallic material such as aluminum is used as an internal sound-absorbing material, for example, a 0.1 mm thick porous foil, it is difficult to vibrate because of its high surface rigidity, and a sound-absorbing performance is exhibited. However, when a metal material is used, the light transmittance and transparency deteriorate as opposed to the improvement in sound absorption. On the other hand, if the use of a metal material is avoided, the sound absorption property is lowered as opposed to the improvement in translucency and transparency. As described above, it is difficult to improve the sound-absorbing property, the light-transmitting property, and the visibility.

An object of the present invention is to provide a translucent sound-absorbing panel capable of improving sound-absorbing properties and also improving translucency and transparency.

The present invention provides the following translucent sound-absorbing panel.

(1) a surface perforated plate facing the sound source and including a material having translucency and transparency and having a plurality of through holes,

A back surface sound insulating plate disposed behind the surface perforated plate with respect to the sound source and made of a material having translucency and transparency;

A sound insulating plate disposed between the surface plate and the rear sound insulating plate to separate a space between the surface plate and the rear sound insulating plate into a plurality of spaces and having a plurality of through holes Having an inner perforated plate,

Wherein the thickness of the inner perforated plate is 0.2 mm or more and 1.5 mm or less.

According to the above configuration, when the thickness of the inner perforated plate is less than 0.2 mm, the surface rigidity of the inner perforated plate is lowered and the inner perforated plate is vibrated, so that the speed of the sound wave passing through the perforated hole is reduced relative to the through- The sound absorption performance deteriorates. In addition, if the plate thickness of the inner perforated plate is thicker than 1.5 mm, the hole diameter of the through hole which can be drilled at a low cost becomes large, and the sound absorption rate decreases. Therefore, the plate thickness of the inner perforated plate should be 0.2 mm or more and 1.5 mm or less. Then, the surface rigidity of the inner perforated plate is improved to make it difficult to vibrate, and the hole diameter of the through hole that can be drilled at low cost is reduced, so that the sound absorption rate is improved. Since a metal material for reinforcement is not used, light transmittance and transparency are improved. Therefore, it is possible to improve the sound-absorbing property and also improve the light-transmitting property and the transparency.

(2) where? Is an aperture ratio of the inner porous plate, t is a plate thickness of the inner porous plate, d is a hole diameter of the through hole of the inner porous plate,? Is a density of the plate portion of the inner porous plate, that the at least when the ρ _0, the inner perforated plate of the the surface density of the plate portion is the inside of the perforated plate divided by the surface density of the through-hole parts of the air and surface density ratio η is represented by the following formula is 1.0 (1). ≪ / RTI >

According to the above configuration, when the surface density ratio? Is smaller than 1.0, that is, the mass of the plate portion of the inner perforated plate is relatively small as compared with the mass of air in the through hole, The vibration speed of the plate portion is increased and the relative speed between the vibration speed of the air passing through the through hole and the vibration speed of the plate portion is lowered and the sound absorbing effect due to the viscous damping is less likely to be exerted efficiently. Therefore, when the surface density ratio? Is 1.0 or more, that is, when the mass of the plate portion of the inner perforated plate is relatively increased compared with the mass of the air in the through hole, the plate portion is less likely to vibrate, The relative velocity between the vibration velocity of the air passing through the through-hole and the vibration velocity of the plate portion is increased. As a result, the sound absorbing effect due to the viscous damping can be efficiently exhibited.

(3) The translucent sound-absorbing panel according to (1) or (2), wherein the material of the inner perforated plate is a resin.

According to the above-described configuration, by making the inner perforated plate made of resin, it is possible to suppress the cost and make it easy to perforate a large number of through holes.

(4) The translucent sound-absorbing panel according to any one of (1) to (3), wherein a plurality of the inner perforated plates are provided and are spaced apart from each other.

According to the above configuration, by providing a plurality of inner porous plates, sound waves pass through the plurality of through holes, so that sound absorption performance can be improved.

(5) a partition plate provided in each of the plurality of spaces, the partition plate including a material having translucency and transparency,

The translucent sound-absorbing panel according to any one of (1) to (4), wherein the inner perforated plate is sandwiched between two or more partition plates.

According to the above configuration, the inner perforated plate is sandwiched between two or more partition plates, and the vibration of the inner perforated plate is suppressed, so that the sound absorbing performance can be improved. Since the partition plate has translucency and transparency, deterioration of translucency and transparency can be suppressed as compared with the case where the inner perforated plate is sandwiched and supported by the metal material.

(6) The translucent sound-absorbing panel according to (5), wherein a plurality of the partition plates are aligned in a straight line while sandwiching the inner perforated plate from the surface perforated plate through the rear surface sound-insulating plate.

According to the above arrangement, by winding the plurality of partition plates in a straight line, the wind load received by the surface porous plates can be received by the plurality of partition plates and the rear surface sound insulating plates. Therefore, the strength of the entire panel can be improved.

(7) The translucent sound-absorbing panel according to any one of (1) to (6), wherein the thickness of the surface perforated plate is 2 mm or more and 3 mm or less.

According to the above configuration, when the thickness of the surface perforated plate is less than 2 mm, the surface perforated plate becomes insufficient in strength, for example, it can not satisfy the reference value of wind load on the road of 300 kg / m 2. Further, if the plate thickness of the surface perforated plate is larger than 3 mm, the cost becomes high and it becomes difficult to perforate a large number of through holes. Therefore, the thickness of the surface perforated plate should be 2 mm or more and 3 mm or less, preferably 2 mm or less. Thus, since the strength of the surface perforated plate is improved, the reference value of wind load on the road of 300 kg / m < 2 > can be satisfied. Further, the cost can be suppressed, and a large number of through holes can be easily formed.

(8) The translucent sound-absorbing panel according to any one of (1) to (7), wherein the material of the surface perforated plate is a resin.

According to the above-described structure, by making the surface plate of a resin, it is possible to suppress the cost and to easily perforate a large number of through holes.

(9) The translucent sound-absorbing panel according to any one of (1) to (8), wherein the thickness of the rear sound-insulating panel is 5 mm or more and 16 mm or less.

According to the above configuration, when the plate thickness of the rear sound insulation plate is less than 5 mm, the entire panel becomes insufficient in strength and the sound insulation performance of the rear sound insulation plate is lowered, so that the acoustic transmission loss of the panel becomes, for example, . Further, if the plate thickness of the back surface sound insulating plate is thicker than 16 mm, the cost becomes high. Therefore, the plate thickness of the back surface sound insulating plate is set to 5 mm or more and 16 mm or less, preferably 8 mm. As a result, the strength of the entire panel can be sufficiently secured and the sound-permeation loss of the panel can be improved to be equal to or higher than the reference value in the road by improving the sound-insulating performance of the rear sound-insulating plate. In addition, the cost can be suppressed.

(10) The translucent sound-absorbing panel according to any one of (1) to (9), wherein the material of the back surface sound insulating plate is resin.

According to the above-described configuration, by using the resin back-side sound insulating plate, the cost can be suppressed.

(11) The translucent sound-absorbing panel according to any one of (1) to (10), wherein a plurality of through-holes are densely formed in a region of a part of the surface perforated plate.

According to the above configuration, in the case where a plurality of through holes are densely formed in a region of a part of the surface perforated plate, a condition that the number of through holes, the opening diameter, and the opening ratio in the surface perforated plate are the same, The area of the surface perforated plate that is not perforated is widened as compared with the case where the perforated plate is formed by dispersing. As a result, the visibility can be improved as compared with the case where the through holes are dispersed.

According to the translucent sound-absorbing panel of the present invention, by setting the plate thickness of the inner perforated plate to 0.2 mm or more and 1.5 mm or less, the surface rigidity of the inner perforated plate is improved and vibration becomes difficult and, at the same time, The hole diameter is reduced, so that the sound absorption rate is improved. Since a metal material for reinforcement is not used, light transmittance and transparency are improved. Therefore, it is possible to improve the sound-absorbing property and also improve the light-transmitting property and the transparency.

1 is a perspective view of a translucent sound-absorbing panel.
2 is a sectional view of the light-transmitting sound-absorbing panel.
3 is a perspective view showing the partition plate and the frame member.
4 (a) and 4 (b) show the relative velocity of the sound wave passing through the through hole with respect to the through hole. FIG. 4 (a) shows a case where the plane density ratio? 4 (b) shows a case where the surface density ratio? Is 1.0 or more.
5 is a plan view showing a surface porous plate.
6 is a graph showing the sound absorption rate of the light-transmitting sound-absorbing panel.
7 is a graph showing the sound absorption rate of the light-transmitting sound-absorbing panel.
8 is a graph showing the sound absorption rate of the light-transmitting sound-absorbing panel.
9 is a graph showing the relationship between the surface density ratio and the sound absorption ratio.
10 is a graph showing the relationship between the surface density ratio and the sound absorption ratio.

Best Mode for Carrying Out the Invention Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(Translucent sound-absorbing panel)

The light-transmitting sound-absorbing panel 1 of the present embodiment has an outer frame 7 which is a rectangular and frame-like shape as shown in FIG. 1 and FIG. 2 which is a sectional view taken along line AA of FIG. 1, And an intermediate frame 8 which is provided between the center of the short side of the other side and the center of the short side of the other side and is parallel to the long side of the outer side frame 7.

The outer frame 7 has a long side of 2 m and a short side of 1 m and is formed into a frame shape by combining four rectilinear frame members 7a to 7d in a rectangular shape. The length of the long side and the length of the short side are not limited to these, and can be appropriately changed. The frame members 7a to 7d and the intermediate frame 8 are made of aluminum and have an H-shaped cross section and are anodized to improve corrosion resistance and wear resistance. The frame members 7a to 7d and the intermediate frame 8 may be made of a material having translucency or transparency.

The light-permeable sound-absorbing panel 1 faces the sound source (not shown), and includes a surface plate 2 having a plurality of through holes 11 and a plurality of through holes 11 arranged behind the surface plate 2 (2) and the back surface sound insulating plate (3) so as to separate the space between the surface perforated plate (2) and the back surface sound insulating plate (3) into a plurality of spaces (9) And has two inner perforated plates 4 (4a, 4b) having a plurality of through holes 14 (14a, 14b). The surface perforated plate 2, the back surface sound insulating plate 3 and the two inner perforated plates 4a and 4b are spaced apart from each other with the space 9 therebetween. The number of the inner perforated plates 4 may be 3 or more, or may be 1 or less.

Each of the surface perforated plate 2, the back surface sound insulating plate 3 and the two inner perforated plates 4 (4a and 4b) is composed of two frames (outer frame 7 and intermediate frame 8) 10a and 10b, respectively. 1, in the frame 10b on the right side in the figure, the surface perforated plate 2, the back surface sound insulating plate 3, and the two inner perforated plates (i.e., 4a and 4b, respectively. Actually, however, there is no opening that penetrates the light-transmitting sound-absorbing panel 1 from the front surface side to the back surface side, and the surface perforated plate 2, the back surface sound-insulating plate 3 and the two inner perforated plates 4 4a, 4b) are housed in the two frames 10a, 10b without gaps, respectively.

The surface perforated plate 2, the back surface sound insulating plate 3 and the inner perforated plate 4 are made of a material having translucency and transparency. In the present embodiment, the material of the surface perforated plate 2, the back surface sound insulating plate 3, and the inner perforated plate 4 is polycarbonate. The material of the surface perforated plate 2, the back surface sound insulating plate 3 and the inner perforated plate 4 is made of synthetic resin such as vinyl chloride, methacrylic resin, styrol resin, ABS resin, ethylene fluoride resin, And may be a material having translucency or transparency such as a material having translucency or transparency and a transparent or semitransparent glass. The surface perforated plate 2, the back surface sound insulating plate 3 and the inner perforated plate 4 are weatherproof treated on both sides.

By using the polycarbonate inner perforated plate 4 as described above, it is possible to suppress the cost and make it easy to perforate a large number of through holes 14. [ In addition, by using a polycarbonate surface plate (2), it is possible to suppress the cost and to easily perforate a large number of through holes (11). In addition, by using the back face-side sound insulating plate 3 made of polycarbonate, the cost can be suppressed.

The through hole (11) of the surface perforated plate (2) generates a viscous damping action with respect to air passing through the through hole (11). In addition, the through holes 14 of the inner perforated plates 4 (4a, 4b) generate a viscous damping action with respect to the air passing through the through holes 14. [ When a viscous damping action occurs in the air passing through the through holes 11 and 14, the air vibration (sound) is converted into thermal energy and attenuation occurs in the air vibration, so that sound waves are absorbed in a relatively wide frequency band. When a plurality of the inner perforated plates 4a and 4b are provided, sound waves pass through the plurality of through holes 14, so that the sound absorbing performance can be further improved.

The aperture ratios of the surface perforated plate 2, the inner perforated plate 4a, and the inner perforated plate 4b are set so as to gradually decrease as they move away from the sound source. In the present embodiment, the aperture ratio of the surface perforated plate 2 is 10% or less, the aperture ratio of the internal perforated plate 4a is 1% or less, and the aperture ratio of the internal perforated plate 4b is 0.5% or less. Thus, by setting the aperture ratio to be smaller as the sound source moves away from the sound source, the sound from the sound source can be reduced stepwise, and as a result, the sound of the wide band can be reduced.

Further, if a plurality of the inner perforated plates 4a and 4b are provided, the light transmittance and the visibility deteriorate as opposed to the improvement of the sound absorption performance. Therefore, in the case of emphasizing the translucency and the transparency rather than the sound-absorbing property, the inner perforated plate 4 may be one or zero sheets.

Here, the through holes 14 (14a and 14b) of the through holes 11 and the inner perforated plates 4 (4a and 4b) of the surface perforated plate 2 are formed by punching, respectively. As described above, by forming the through holes 11 and 14 by punching, a large number of through holes 11 and 14 can be formed at low cost. In addition, when the through holes 11 and 14 are drilled by laser or drill, there is a problem that the hole portions of the resin surface pane 2 and the inner hole plate 4 become whitened to decrease the visibility, This problem does not occur in the case of punching.

The translucent sound-absorbing panels 1 are each provided with three frame members 6 (6a, 6b, 6c), which are rectangular and frame-shaped along the inner periphery of these frames 10a, 10b, respectively, in two frames 10a, . Each of the frame members 6 is made of vinyl chloride. 2, the frame member 6 (6a, 6b, 6c) is provided between the surface perforated plate 2 and the inner perforated plate 4a, between the inner perforated plate 4a and the inner perforated plate 4b And the rear surface sound insulating board 3 and the rear surface sound insulating board 3 are disposed between the inner perforated plate 4b and the rear surface sound insulating plate 3 so as to face the outer frame 7 and the intermediate frame 8, And serves to position the inner perforated plates 4 (4a, 4b) of the sheet, respectively. In this embodiment, the thickness of each frame member 6 (6a, 6b, 6c) in the panel thickness direction (vertical direction in Fig. 2) is 25 mm, The thickness in the panel plane direction (left-right direction in Fig. 2) is 20 mm. The distance between the inner perforated plate 4a and the inner perforated plate 4b and the distance between the inner perforated plate 4b and the back surface sound insulating plate 3 Are set to 25 mm, respectively.

Further, the light-transmitting sound-absorbing panel 1 has partition plates 5 (5a, 5b, 5c) provided in each of the plurality of spaces 9, respectively. Each of the partition plates 5 is made of a material having translucency and transparency. In the present embodiment, the material of the partition plate 5 is polycarbonate. The material of the partition plate 5 is synthetic resin or rubber such as vinyl chloride, methacrylic resin, styrol resin, ABS resin, ethylene fluoride resin and acrylic resin, and is made of a material having translucency or transparency, Or may be a material having translucency or transparency. Both surfaces of the partition plate 5 are weatherproof treated.

When the three partition plates 5a, 5b and 5c are set as one set, the partition plate 5 is provided with three sets of the frame 10a and the frame 10b, (7). The long side of the outer frame 7 is divided into four by the three sets of partition plates 5. The partition plate 5 may be provided in two sets on the frame 10a and the frame 10b so as to divide the long side of the outer frame 7 into three parts. Four sets may be provided for the frame 10a and the frame 10b.

Each of the partition plates 5 (5a, 5b, 5c) is supported by frame members 6 (6a, 6b, 6c). More specifically, as shown in Fig. 3, each of the three partition plates 5a is fitted in an inserting portion formed at two opposite sides of the frame member 6a, And is supported by the frame member 6a. The partition plate 5b and the partition plate 5c are similarly supported by the frame member 6b and the frame member 6c.

Each of the inner perforated plates 4 is sandwiched between two partition plates 5 as shown in Fig. The outer peripheral edges of the inner perforated plates 4a and 4b are sandwiched by the two frame members 6, respectively. Thereby, the vibration of the inner perforated plate 4 is suppressed. Since the partition plate 5 has translucency and transparency, deterioration of translucency and transparency can be suppressed as compared with the case where the inner perforated plate 4 is sandwiched and supported by a metal material.

The three partition plates 5a, 5b and 5c are formed in such a manner that two pieces of the inner perforated plates 4a and 4b are inserted one by one from the surface perforated plate 2 to the rear surface sound- It is sorted. The thickness in the direction orthogonal to the alignment direction of each partition plate 5 (lateral direction in Fig. 2) is 5 mm or more. When the thickness of each partition plate 5 is smaller than 5 mm (for example, 2 mm), each partition plate 5 is collapsed by the wind load received by the surface perforated plate 2, Both ends of the frame member 6 come out of the cut-in portion of the frame member 6. However, if the thickness of each partition plate 5 is 5 mm or more, the wind load received by the surface perforated plate 2 can be received by the plurality of partition plates 5a, 5b, 5c and the rear surface sound insulating plate 3 . As a result, the overall strength of the light-transmitting sound-absorbing panel 1 is improved. In this embodiment, the thickness in the direction orthogonal to the alignment direction of each partition plate 5 is 5 mm.

In this configuration, the plate thickness of the inner perforated plate 4 is 0.2 mm or more and 1.5 mm or less. When the plate thickness of the inner perforated plate 4 is less than 0.2 mm, the surface rigidity of the inner perforated plate 4 is lowered and the inner perforated plate 4 is vibrated so that the through holes 14 of the sound waves passing through the through- So that the sound absorption performance is deteriorated. If the plate thickness of the inner perforated plate 4 is larger than 1.5 mm, the hole diameter of the through hole 14 which can be drilled at a low cost becomes large, and the sound absorption rate decreases. In this regard, when the plate thickness of the inner perforated plate 4 is set to 0.2 mm or more and 1.5 mm or less, the surface rigidity of the inner perforated plate 4 is improved to make it difficult to vibrate and, at the same time, The pore diameter of the pores 14 becomes smaller, so that the sound absorption rate is improved. The hole diameter of the through hole (14) is almost equal to the plate thickness of the inner perforated plate (4). In this embodiment, the plate thickness of the inner perforated plate 4a and the inner perforated plate 4b is 0.3 mm, respectively, and the diameters of the through holes 14a and 14b are 0.3 mm respectively. The hole diameter of the through hole 14a of the inner perforated plate 4a may be different from the hole diameter of the through hole 14b of the inner perforated plate 4b.

The surface density ratio?, Which is a value obtained by dividing the surface density of the plate portion of the inner perforated plate 4 by the surface density of air at the portion of the through hole 14 of the inner perforated plate 4, is 1.0 or more. The aperture ratio of the inner perforated plate 4 is represented by alpha, the thickness of the inner perforated plate 4 by t [m], the hole diameter of the through hole 14 of the inner perforated plate 4 by d [m] the hayeoteul when the perforated plate (4) the density of the plate portion ρ [㎏ / ㎥], of the air density ρ ₀ [㎏ / ㎥], surface density ratio η is represented by the following formula (1). In addition, when there are a plurality of inner perforated plates (for example, 4a and 4b), it means that the surface density ratio? Of each inner perforated plate is 1.0 or more. Further, when there are a plurality of through holes 14, the hole diameter d represents the average value thereof.

When the surface density ratio? Is smaller than 1.0, that is, the mass of the plate portion of the inner perforated plate 4 is relatively small as compared with the mass of air in the through hole 14, The plate portion of the inner perforated plate 4 is easily vibrated and the vibration velocity b of the plate portion becomes large so that the vibration velocity a of the air passing through the through hole 14 and the vibration velocity b of the plate portion The relative speed c is lowered, and the sound absorbing effect due to the viscous damping is less likely to be exerted efficiently. Therefore, when the surface density ratio? Is 1.0 or more, that is, when the mass of the plate portion of the inner perforated plate 4 is relatively increased as compared with the mass of air in the through hole 14, , The plate portion is less likely to vibrate and the vibration velocity b 'of the plate portion becomes smaller, so that the relative velocity between the vibration velocity a of the air passing through the through hole 14 and the vibration velocity b' of the plate portion c 'increases. As a result, the sound absorbing effect due to the viscous damping can be effectively exhibited.

The thickness of the surface perforated plate 2 is 2 mm or more and 3 mm or less, preferably 2 mm or less. If the plate thickness of the surface perforated plate 2 is less than 2 mm, the surface perforated plate 2 becomes insufficient in strength, for example, the standard value of wind load on the road of 300 kg / m2 can not be satisfied. In addition, if the thickness of the surface perforated plate 2 is larger than 3 mm, the cost becomes high and it becomes difficult to perforate a large number of through holes 11. [ In this regard, when the thickness of the surface perforated plate 2 is 2 mm or more and 3 mm or less, preferably 2 mm, the strength of the surface perforated plate 2 is improved. Therefore, 300 kg / m < 2 > can be satisfied. In addition, the cost can be suppressed, and a large number of through holes 11 can be easily formed. The hole diameter of the through hole (11) is almost equal to the plate thickness of the surface perforated plate (2). In the present embodiment, the thickness of the surface perforated plate 2 is 2 mm, and the diameter of the through-hole 11 is 1.9 mm.

Further, the thickness of the back surface sound insulating plate 3 is 5 mm or more and 16 mm or less, preferably 8 mm. If the plate thickness of the back side sound insulating plate 3 is less than 5 mm, the entire light transmitting sound absorbing panel 1 becomes insufficient and the sound insulating performance of the back side sound insulating plate 3 is lowered, For example, falls below the standard on the road. In addition, if the plate thickness of the back surface sound insulating plate 3 is thicker than 16 mm, the cost becomes high. In this regard, when the plate thickness of the back surface sound insulating plate 3 is 5 mm or more and 16 mm or less, preferably 8 mm, the strength of the entire light transmitting sound absorbing panel 1 can be sufficiently secured, The sound transmission performance of the light-transmitting sound-absorbing panel 1 can be improved to be equal to or higher than the reference value on the road by improving the sound-insulating performance of the light-absorbing panel 3. In addition, the cost can be suppressed. In the present embodiment, the thickness of the back surface sound insulating plate 3 is 8 mm.

Since the metal material for reinforcing the perforated plate surface itself is not used at all in the light-transmitting sound-absorbing panel 1, transmittance and transparency are improved as compared with the case where a metal material is used for reinforcement.

5, the plurality of through holes 11 of the surface perforated plate 2 may be densely formed in a part of the area of the surface perforated plate 2. In this case, In this way, when a large number of through holes 11 are densely formed in a part of the surface of the surface perforated plate 2, the number of through holes 11 in the surface perforated plate 2, the opening diameter, The area which is not perforated in the surface perforated plate 2 is widened as compared with the case where a large number of through holes 11 are dispersed. As a result, visibility can be improved as compared with the case where the through holes 11 are dispersed.

(Measurement of sound absorption rate)

Next, the sound absorption rate of the light-transmitting sound-absorbing panel was measured. 6 shows the sound absorption rate of the light-transmitting sound-absorbing panel when the thickness of the surface perforated plate 2 is 3 mm and the thickness of each of the two internal perforated plates 4a and 4b is 0.075 mm. 6 is the sound absorption rate, and the horizontal axis is the 1/3 octave center frequency (Hz). Further, the thickness of the back surface sound insulating plate 3 is equivalent to 8 mm. Here, the thickness of 0.075 mm, which is the thickness of each of the two inner porous plates 4a and 4b, is a thickness that exhibits sound absorbing performance when the inner porous plate is made of a metal material such as aluminum. With respect to the sound absorption rate (calculated value) in the case where there is no influence of the plate vibration, the sound absorption rate is reduced in the range of 500 Hz to 1,250 Hz due to the influence of the plate vibration.

Next, the sound absorption ratios (measured values) of the light-transmitting sound-absorbing panels in the case where the plate thicknesses of the two inner perforated plates 4a and 4b are set to 0.075 mm, 0.1 mm, 0.2 mm, 0.25 mm, and 0.3 mm, respectively, Fig. 7 shows the measurement results. 7 is the sound absorption rate, and the horizontal axis is the 1/3 octave center frequency (Hz). Here, the thickness of the surface perforated plate 2 is 3 mm, and the thickness of the back surface sound insulating plate 3 is 8 mm. The thickness of each of the two inner perforated plates 4a and 4b is 0.2 mm or more than that of the transparent perforated panel in which the thickness of each of the two inner perforated plates 4a and 4b is less than 0.2 mm, The sound absorption rate of the sound absorption panel 1 is high. This is because the surface rigidity of the inner perforated plates 4a and 4b is improved by increasing the plate thickness of the inner perforated plates 4a and 4b and the plate vibrations are reduced. As a result, The relative speed with respect to the through hole 14 is increased, and a viscous damping action is generated in the air passing through the through hole 14, so that a sound absorbing effect is exerted.

8 shows the sound absorption rate (calculated value) of the light-transmitting sound-absorbing panel when the thickness of each of the two inner perforated plates 4 is set to be 0.5 mm, 1 mm, 1.5 mm and 2 mm, respectively . 8 is the sound absorption rate, and the horizontal axis is the 1/3 octave center frequency (Hz). Here, the thickness of the surface perforated plate 2 is 3 mm, and the thickness of the back surface sound insulating plate 3 is 8 mm. It can be seen that as the thickness of the inner perforated plates 4a and 4b increases, the sound absorption rate decreases. This is because as the plate thickness of the inner perforated plates 4a and 4b increases, the hole diameter of the through hole 14 becomes larger due to processing restrictions, and as a result, the damping effect due to the viscous damping action becomes smaller and the sound absorption rate becomes lower to be. It is preferable that the plate thickness of the inner porous plates 4a and 4b is 1.5 mm or less in order to realize a sound absorption coefficient of about 0.7 in the band of 400 Hz and 0.8 in the band of 1000 Hz.

Thus, it is preferable that the thickness of each of the two inner porous plates 4a and 4b is 0.2 mm or more and 1.5 mm or less.

(Relationship between face density ratio and sound absorption ratio)

Next, the relationship between the surface density ratio? And the sound absorption ratio was calculated. A sound absorbing structure was constituted of one perforated plate and an air layer. The material of the perforated plate was made of polycarbonate, the aperture ratio of the perforated plate was 0.20%, the hole diameter of the through hole was 0.3 mm, the thickness of the air layer behind the perforated plate was 9 shows the sound-absorbing performance of the sound-absorbing structure when the surface density ratio? Shown in the equation (1) is changed by changing the plate thickness of the perforated plate. The ordinate of Fig. 9 is the sound absorption ratio, and the abscissa is the surface density ratio?. Here, the sound absorption ratio is obtained by dividing the maximum sound absorption rate when the plate vibration is taken into consideration by the sound absorption by the plurality of through holes, by the maximum sound absorption rate when only the sound absorption by the plurality of through holes is considered. Therefore, the sound absorption ratio ratio indicates the influence of the plate vibration on sound absorption by a plurality of through holes, and when the sound absorption ratio is less than 1, the sound absorption rate is lowered due to the influence of the plate vibration. As a result of the calculation, the reason why the sound absorption ratio is 0.7 or more is that the surface density ratio? Is 0.6 or more. As the plate thickness of the perforated plate increases, the surface density ratio eta increases, so that the larger the plate thickness of the perforated plate, the better the sound absorption performance.

Next, a sound absorbing structure is constituted of one perforated plate and an air layer, the material of the perforated plate is made of aluminum, the aperture ratio of the perforated plate is set to 0.20%, the perforation hole diameter is set to 0.1 mm, Fig. 10 shows the sound absorbing performance of the sound absorbing structure in which the surface density ratio? Shown by the formula (1) is changed by changing the plate thickness of the perforated plate to 40 mm. As a result of the calculation, the reason why the absorptivity ratio becomes 0.7 or more is that the surface density ratio? Is 1.0 or more.

From the above, it is preferable to set the plate thickness of the inner perforated plate 4 so that the surface density ratio eta is 1.0 or more. The calculation results shown in Figs. 9 and 10 are for one perforated plate, but also for a case where a plurality of perforated plates are combined, similarly, the larger the surface density ratio?, The higher the sound absorbing performance. The sound absorption performance is improved in the range where the surface density ratio? Is 1.0 or more.

(Measurement of total light transmittance)

Next, the total light transmittance of the light-transmitting sound-absorbing panel was measured. The translucency sound-absorbing panel of the present embodiment had a total light transmittance of 60%, while the translucent sound-absorbing panel of the structure in which the translucent resin film was reinforced with expanded metal had a total light transmittance of 24%. From this, it can be seen that the light transmittance and the transmissivity are improved unless a metal material for reinforcement is used at all.

(effect)

As described above, according to the translucent sound-absorbing panel 1 of the present embodiment, the thickness of the inner perforated plate 4 is 0.2 mm or more and 1.5 mm or less. When the plate thickness of the inner perforated plate 4 is less than 0.2 mm, the surface rigidity of the inner perforated plate 4 is lowered and the inner perforated plate 4 is vibrated so that the through holes 14 of the sound waves passing through the through- And the sound absorption performance is deteriorated. If the plate thickness of the inner perforated plate 4 is larger than 1.5 mm, the hole diameter of the through hole 14 which can be drilled at a low cost becomes large, and the sound absorption rate is lowered. Therefore, the thickness of the inner perforated plate 4 is set to 0.2 mm or more and 1.5 mm or less. In this case, the surface rigidity of the inner perforated plate 4 is improved to make it difficult to vibrate, and the hole diameter of the through hole 14 that can be drilled at low cost is reduced, so that the sound absorption rate is improved. Since a metal material for reinforcement is not used, light transmittance and transparency are improved. Therefore, it is possible to improve the sound-absorbing property and also improve the light-transmitting property and the transparency.

Further, when the surface density ratio? Is smaller than 1.0, that is, the mass of the plate portion of the inner perforated plate is relatively small as compared with the mass of the air in the through hole, the plate portion is easily vibrated, The relative speed between the oscillation speed of the air passing through the through hole and the oscillation speed of the plate portion is lowered and the sound absorbing effect due to the viscous damping is less likely to be exerted efficiently. Therefore, when the surface density ratio? Is 1.0 or more, that is, when the mass of the plate portion of the inner perforated plate is relatively increased compared with the mass of the air in the through hole, the plate portion is less likely to vibrate, The relative velocity between the vibration velocity of the air passing through the through-hole and the vibration velocity of the plate portion is increased. As a result, the sound absorbing effect due to the viscous damping can be efficiently exhibited.

In addition, by forming the inner perforated plate 4 made of a resin (e.g., polycarbonate), it is possible to suppress the cost and make it easy to perforate a large number of through holes 14. [

Further, by providing a plurality of the inner perforated plates 4, the sound waves pass through the plurality of through holes 14, so that the sound absorbing performance can be improved.

In addition, the inner perforated plate 4 is sandwiched between two or more partition plates 5 to suppress the vibration of the inner perforated plate 4, so that the sound absorbing performance can be improved. Since the partition plate 5 has translucency and transparency, deterioration of translucency and transparency can be suppressed as compared with the case where the inner perforated plate 4 is sandwiched and supported by a metal material.

In addition, by aligning the plurality of partition plates 5 in a straight line, the wind load received by the surface perforated plate 2 can be received by the plurality of partition plates 5 and the rear surface sound insulating plate 3. [ Therefore, the strength of the entire light-transmitting sound-absorbing panel 1 can be improved.

The thickness of the surface perforated plate 2 is 2 mm or more and 3 mm or less, preferably 2 mm. If the plate thickness of the surface perforated plate 2 is less than 2 mm, the surface perforated plate 2 becomes insufficient in strength, for example, the standard value of wind load on the road of 300 kg / m2 can not be satisfied. In addition, if the thickness of the surface perforated plate 2 is larger than 3 mm, the cost becomes high and it becomes difficult to perforate a large number of through holes 11. [ Therefore, the thickness of the surface perforated plate 2 is 2 mm or more and 3 mm or less, preferably 2 mm. Thus, since the strength of the surface perforated plate 2 is improved, it is possible to satisfy the reference value of wind load on the road of 300 kg / m < 2 >. In addition, the cost can be suppressed, and a large number of through holes 11 can be easily formed.

In addition, by using the surface perforated plate 2 made of a resin (for example, polycarbonate), it is possible to suppress the cost and make it easy to perforate a large number of through holes 11. [

Further, the thickness of the back surface sound insulating plate 3 is 5 mm or more and 16 mm or less, preferably 8 mm. If the plate thickness of the back side sound insulating plate 3 is less than 5 mm, the entire light transmitting sound absorbing panel 1 becomes insufficient and the sound insulating performance of the back side sound insulating plate 3 is lowered, For example, falls below the standard on the road. In addition, if the plate thickness of the back surface sound insulating plate 3 is thicker than 16 mm, the cost becomes high. Therefore, the thickness of the back surface sound insulating plate 3 is set to 5 mm or more and 16 mm or less, preferably 8 mm. As a result, the strength of the entire light-transmitting sound-absorbing panel 1 can be sufficiently secured, and the sound-insulating performance of the rear-face sound-insulating board 3 is improved, so that the acoustic transmission loss of the panel can be improved to be higher than the reference value on the road . In addition, the cost can be suppressed.

In addition, by using the back surface sound insulating plate 3 made of resin (e.g., polycarbonate), the cost can be suppressed.

Further, a plurality of through holes 11 are formed in a concentrated manner in a region of a part of the surface perforated plate 2. The number of the through holes 11 in the surface perforated plate 2, the opening diameter, and the opening ratio are the same in the case where a plurality of through holes 11 are formed in a concentrated manner in a part of the surface of the surface perforated plate 2 The non-perforated area of the surface perforated plate 2 is widened as compared with the case where a large number of through holes 11 are dispersed on the high surface. As a result, visibility can be improved as compared with the case where the through holes 11 are dispersed.

(Modification of this embodiment)

Although the embodiment of the present invention has been described above, the present invention is merely illustrative of specific examples, and the present invention is not particularly limited, and specific configurations and the like can be appropriately changed in design. The functions and effects described in the embodiments of the invention are merely the most appropriate actions and effects arising from the present invention, and the functions and effects of the present invention are not limited to those described in the embodiments of the present invention .

2, the distance between the inner perforated plate 4a and the inner perforated plate 4b, and the distance between the inner perforated plate 4a and the inner perforated plate 4b, for example, Although the interval between the inner perforated plate 4b and the rear face sound insulating plate 3 is set to 25 mm each, the arrangement is not limited to this, and the intervals may be different from each other.

In the present embodiment, the aperture ratios of the surface perforated plate 2, the inner perforated plate 4a, and the inner perforated plate 4b are set so as to gradually decrease as they move away from the sound source, but the present invention is not limited thereto , The aperture ratio of the surface perforated plate 2 may be equal to the aperture ratio of the inner perforated plate 4a or the aperture ratio of the inner perforated plate 4a may be equal to the aperture ratio of the inner perforated plate 4b, ), The inner perforated plate 4a and the inner perforated plate 4b may all have the same opening ratio.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, but can be variously modified within the scope of the claims.

The present application is based on Japanese Patent Application (Japanese Patent Application No. 2011-226316) filed on October 14, 2011, the content of which is incorporated herein by reference.

According to the translucent sound-absorbing panel of the present invention, by setting the plate thickness of the inner perforated plate to 0.2 mm or more and 1.5 mm or less, the surface rigidity of the inner perforated plate is improved and vibration becomes difficult and, at the same time, The hole diameter is reduced, so that the sound absorption rate is improved. Since a metal material for reinforcement is not used, light transmittance and transparency are improved. Therefore, it is possible to improve the sound-absorbing property and also improve the light-transmitting property and the transparency.

1: Transmissive sound-absorbing panel
2: surface plate
3: Rear sound insulating plate
4a, 4b: inner perforated plate
5a, 5b, 5c: partition plate
6a, 6b, 6c:
7: outer frame
8: Middle frame
9: Space
10a, 10b: frame
11, 14: Through holes

Claims (11)

A surface perforated plate facing the sound source and including a material having translucency and transparency and having a plurality of through holes,
A back surface sound insulating plate disposed behind the surface perforated plate with respect to the sound source and made of a material having translucency and transparency;
A sound insulating plate disposed between the surface plate and the rear sound insulating plate to separate a space between the surface plate and the rear sound insulating plate into a plurality of spaces and having a plurality of through holes Having an inner perforated plate,
Wherein a thickness of the inner perforated plate is 0.2 mm or more and 1.5 mm or less. And a density of the plate portion of the inner perforated plate is denoted by p, and a density of the plate portion of the inner perforated plate is denoted by < RTI ID = 0.0 > And the surface density of the plate portion of the inner perforated plate divided by the surface density of the air of the perforated hole portion of the inner perforated plate when the air density is p ₀ , Lt; RTI ID = 0.0 > 1.0 < / RTI >

The translucent sound-absorbing panel according to claim 1, wherein the material of the inner perforated plate is a resin. The light-transmitting sound-absorbing panel according to claim 1, wherein a plurality of the inner perforated plates are provided and are spaced from each other. The liquid crystal display device according to claim 1, further comprising: a partition plate provided in each of the plurality of spaces, the partition plate including a material having translucency and transparency,
Wherein the inner perforated plate is sandwiched between two or more partition plates. The translucent sound-absorbing panel according to claim 5, wherein a plurality of the partition plates are aligned in a straight line while sandwiching the inner perforated plate from the surface perforated plate through the rear face sound-insulating plate. The translucent sound-absorbing panel according to claim 1, wherein the thickness of the surface perforated plate is 2 mm or more and 3 mm or less. The translucent sound-absorbing panel according to claim 1, wherein the material of the surface perforated plate is a resin. The translucent sound-absorbing panel according to claim 1, wherein the thickness of the rear sound insulation panel is 5 mm or more and 16 mm or less. The translucent sound-absorbing panel according to claim 1, characterized in that the material of the rear sound-insulating panel is a resin. The light-permeable sound-absorbing panel according to claim 1, wherein a plurality of through-holes are formed in a concentrated manner in a region of a part of the surface perforated plate.

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