Acoustic lens and loudspeaker system
The acoustic lens with varying partition plates and hole configurations addresses sound leakage issues in speaker systems by sharpening directivity, focusing sound waves on the intended user.
Patent Information
- Application Number
- CN202380036858.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-04-27
- Filing Date
- 2023-05-08
- Publication Date
- 2024-12-20
AI Technical Summary
Existing speaker systems face issues with sound leakage to unintended recipients due to uniform sound wave directivity, which affects users seated adjacent or behind the target user.
An acoustic lens with multiple partition plates of varying lengths and hole configurations is used to control sound wave directivity, adjusting the path length based on the number of holes traversed, thereby focusing sound waves on the intended user.
The acoustic lens effectively suppresses sound leakage to unintended users by sharpening directivity, ensuring sound is primarily directed towards the intended recipient.
Smart Images
Figure CN119174194A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to an acoustic lens and a speaker system for controlling the directivity of sound. Background Art
[0002] Patent Document 1 discloses an acoustic lens that improves the directivity of a parallel-progressing sound wave into a spherical wave.
[0003] Prior art literature
[0004] Patent Literature
[0005] Patent Document 1: Japanese Utility Model Application Laid-Open No. 55-155179 Summary of the invention
[0006] Problems to be solved by the invention
[0007] An object of the present disclosure is to provide an acoustic lens or the like that can easily control the directivity of sound waves.
[0008] Means used to solve problems
[0009] An acoustic lens of a technical solution of the present disclosure includes a plurality of first partition plates arranged at intervals in the traveling direction of sound waves emitted from a speaker. The plurality of first partition plates each have a plurality of holes through which the sound waves pass. The lengths of the first direction of the plurality of first partition plates are different from each other.
[0010] Furthermore, a speaker system according to one aspect of the present disclosure includes the acoustic lens and the speaker that emits the sound wave to the acoustic lens.
[0011] Effects of the Invention
[0012] According to the present disclosure, there is an advantage that the directivity of sound waves can be easily controlled. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 1 is a schematic diagram showing a speaker system of a comparative example.
[0014] Figure 2 This is a schematic diagram showing an example of use of a speaker system including the acoustic lens according to the embodiment.
[0015] Figure 3 This is a schematic diagram showing the structure of an acoustic lens according to an embodiment.
[0016] Figure 4 It is an explanatory diagram of the directivity of the acoustic lens according to the embodiment.
[0017] Figure 5This is a schematic diagram showing the structure of an acoustic lens according to a first modified example of the embodiment.
[0018] Figure 6 It is a schematic diagram showing the structure of an acoustic lens according to a second modified example of the embodiment.
[0019] Figure 7 It is an explanatory diagram of the directivity of the acoustic lens according to the second modified example of the embodiment.
[0020] Figure 8 It is a schematic diagram showing the structure of an acoustic lens according to a third modified example of the embodiment. DETAILED DESCRIPTION
[0021] (Understanding that is the basis of the present disclosure)
[0022] Conventionally, there is known a speaker system which is installed in a seat of a mobile body such as a car, an airplane, or a train, and which reproduces sound, music, etc. for a user sitting in the seat. Figure 1 2 is a schematic diagram showing a speaker system 200 of a comparative example. The speaker system 200 of the comparative example is provided in the headrest 31 of the seat 3. Figure 1 In the illustrated example, the speaker system 200 of the comparative example is installed near the left ear and the right ear of the user U1 sitting in the seat 3 .
[0023] Here, in the speaker system 200 of the comparative example, the directivity of the sound waves emitted from the speaker is the same in the front direction of the speaker. Therefore, in the speaker system 200 of the comparative example, the sound or music reproduced by the speaker is likely to leak to the person sitting in the seat next to the seat 3 and the person sitting in the seat behind the seat 3. That is, in the speaker system 200 of the comparative example, there is a technical problem that the sound is likely to leak to other than the target user U1.
[0024] In view of the above, the present disclosure aims to provide an acoustic lens or the like that can easily suppress sound leakage to persons other than the target user U1 by easily controlling the directivity of sound waves by carefully designing the structure of the acoustic lens.
[0025] More specifically, the acoustic lens of the first technical solution of the present disclosure includes a plurality of first partition plates arranged at intervals in the traveling direction of the sound waves emitted from the speaker. The plurality of first partition plates each have a plurality of holes through which the sound waves pass. The lengths of the first direction of the plurality of first partition plates are different from each other.
[0026] Thus, the length of the path through which the sound wave passes can be adjusted according to the number of holes through which the sound wave passes in the first direction, so there is an advantage that the directivity of the sound wave can be easily controlled.
[0027] Furthermore, for example, according to the acoustic lens of the second aspect of the present disclosure, in the first aspect, the plurality of first partition plates are arranged such that the number of overlapping plates in the propagation direction of the sound wave decreases from one direction toward the other direction in the first direction.
[0028] This has the advantage of easily controlling which side of the first direction has the directivity of the sound wave.
[0029] In addition, for example, the acoustic lens of the third technical solution of the present disclosure, in the first or second technical solution, further comprises a plurality of second partition plates that overlap with the plurality of first partition plates in the direction of travel of the sound wave and are arranged at intervals. The plurality of second partition plates each have a plurality of holes through which the sound wave passes. The lengths of the second directions intersecting the first direction of the plurality of second partition plates are different from each other.
[0030] Thus, the directivity of the sound wave in the first direction is controlled by multiple first partitions, and the directivity of the sound wave in the second direction is controlled by multiple second partitions, so there is an advantage that it is easy to control the directivity of the sound wave in each of the two intersecting directions.
[0031] Furthermore, for example, in the acoustic lens according to a fourth aspect of the present disclosure, in the third aspect, the plurality of second partition plates are arranged so that the number of overlaps in the propagation direction of the sound wave decreases as they go away from the center in the second direction.
[0032] This has the advantage of easily providing the center side in the second direction with directivity of the sound wave.
[0033] Furthermore, for example, in the acoustic lens according to the fifth aspect of the present disclosure, in the third or fourth aspect, the first direction and the second direction are orthogonal to each other.
[0034] Therefore, for example, if the first direction is set as the horizontal direction and the second direction is set as the vertical direction, there is an advantage that the directivity of the sound wave can be easily controlled in each of the horizontal direction and the vertical direction.
[0035] Furthermore, for example, in the acoustic lens according to a sixth aspect of the present disclosure, in any one of the first to fifth aspects, the diameters of the plurality of holes decrease as they are farther from the speaker in the direction in which the sound waves travel.
[0036] Therefore, compared with a case where the diameters of the plurality of holes are the same, the greater the number of holes through which the sound waves pass, the longer the length of the path through which the sound waves pass, so there is an advantage that the directivity of the sound waves can be sharpened.
[0037] Furthermore, for example, in the acoustic lens according to claim 7 of the present disclosure, in any one of claims 1 to 6, at least a portion of the plurality of holes do not overlap with each other in the propagation direction of the acoustic wave.
[0038] This makes it possible to lengthen the path through which the sound waves pass, compared to a case where all the holes overlap with each other in the direction in which the sound waves travel, thereby having the advantage that the directivity of the sound waves can be sharpened.
[0039] Furthermore, for example, a speaker system according to an eighth aspect of the present disclosure includes: the acoustic lens according to any one of the first to seventh aspects; and a speaker that emits sound waves to the acoustic lens.
[0040] This has the advantage of being able to produce the same effect as the above-mentioned acoustic lens.
[0041] Hereinafter, the embodiments are specifically described with reference to the accompanying drawings. In addition, the embodiments described below all represent general or specific examples. The numerical values, shapes, materials, constituent elements, the configuration positions of constituent elements and the connection forms, steps or the order of steps, etc., shown in the following embodiments are used as an example and are not intended to limit the present disclosure. In addition, there are cases where geometric expressions such as parallel or orthogonal are used, but these expressions do not represent mathematical rigor, but include substantially allowed errors or deviations, etc. For example, in the following description, as long as the angle formed by two directions intersecting each other is 90 degrees ± 1 to 5%, it can be said that the two directions are orthogonal. In addition, expressions such as simultaneous or identical also include substantially allowed ranges.
[0042] In addition, regarding the constituent elements of the following embodiments that are not described in the independent claims, they are described as arbitrary constituent elements. In addition, each figure is a schematic diagram and is not necessarily a strict illustration. In addition, in each figure, the same reference numerals are given to substantially the same structure, and there are cases where repeated descriptions are omitted or simplified.
[0043] (Implementation Method)
[0044] [1.Structure]
[0045] Hereinafter, the acoustic lens 1 according to the embodiment and the speaker system 100 including the acoustic lens 1 will be described. Figure 2 1 is a schematic diagram showing an example of use of the speaker system 100 including the acoustic lens 1 according to the embodiment. Figure 2 In the figure, the speaker 2 is omitted. Figure 3 It is a schematic diagram showing the structure of the acoustic lens 1 according to the embodiment. Figure 4 It is an explanatory diagram of the directivity of the acoustic lens 1 according to the embodiment.
[0046] The speaker system 100 is as follows Figure 2 As shown, an acoustic lens 1 and a speaker 2 (see Figure 4The speaker system 100 is used to allow a user U1 as a target to listen to a sound wave W1 emitted from a speaker 2 and radiated through an acoustic lens 1 (see Figure 4 ) system.
[0047] In the embodiment, the speaker system 100 is provided at the seats 3 and 3A of a mobile body such as a car. In the following, it is assumed that the seat 3 is the driver's seat of the car and the seat 3A is the front passenger seat of the car for description. The seats 3 and 3A are arranged in the left-right direction (horizontal direction) of the car on the front side of the car. In the following, unless otherwise stated, the left-right direction (horizontal direction) of the car is set as the "first direction d1" for description. In addition, unless otherwise stated, the height direction (vertical direction) of the car is set as the "second direction d2" for description.
[0048] The speaker systems 100 are respectively provided at both ends of the headrest 31 of the seat 3 in the first direction d1. That is, the speaker systems 100 are respectively provided near the left ear and the right ear of the user U1 sitting on the seat 3. In addition, the speaker systems 100 are respectively provided at both ends of the headrest 31A of the seat 3A in the first direction d1. That is, the speaker systems 100 are respectively provided near the left ear and the right ear of the user U2 sitting on the seat 3A.
[0049] The speaker 2 is a device that outputs a sound wave W1 by converting an electrical signal such as a sound signal into vibration of a vibration plate. The size, shape or structure of the vibration plate, magnetic circuit or frame constituting the speaker 2 is not particularly limited. In the embodiment, the speaker 2 is an electric speaker having a conical vibration plate. The speaker 2 emits a sound wave W1 to the acoustic lens 1. As a result, the sound wave W1 emitted from the speaker 2 passes through the acoustic lens 1 and is radiated to the outside (atmosphere).
[0050] Acoustic lens 1 Figure 3 As shown, there are a plurality of (here, five) first partition plates 11. Each first partition plate 11 is a flat plate and is a member that does not easily vibrate. The material constituting each first partition plate 11 is, for example, wood, resin, metal, or ceramic, etc., and is not particularly limited.
[0051] Multiple first partition plates 11 such as Figure 3 and Figure 4 As shown, the first partition plates 11 are arranged at intervals in the direction of travel of the sound wave W1 emitted from the speaker 2. In addition, although not shown, each first partition plate 11 can be supported by a frame-shaped member provided at the outer periphery of each first partition plate 11, or can be supported by a spacer provided between adjacent first partition plates 11.
[0052] Here, the "propagation direction of the sound wave W1" is the propagation direction of the sound wave W1 emitted from the speaker 2, not the propagation direction of the sound wave W1 passing through the acoustic lens 1. In the embodiment, the propagation direction of the sound wave W1 corresponds to a direction orthogonal to both the first direction d1 and the second direction d2.
[0053] Here, as described above, in the embodiment, the first direction d1 is the horizontal direction, and the second direction d2 is the vertical direction. Therefore, in the embodiment, the first direction d1 and the second direction d2 are orthogonal to each other. In addition, the first direction d1 and the second direction d2 may cross each other or may not be orthogonal to each other.
[0054] The plurality of first partition plates 11 are respectively Figure 3 As shown, there are a plurality of holes 110 through which the sound wave W1 passes. In the embodiment, the hole 110 is circular in a plan view (i.e., viewed from the traveling direction of the sound wave W1), and penetrates the first partition plate 11 in the thickness direction (i.e., the traveling direction of the sound wave W1). In addition, in the embodiment, in each first partition plate 11, the plurality of holes 110 are arranged in a matrix of m (m is a natural number) arranged in the first direction d1 and n (n is a natural number) arranged in the second direction d2.
[0055] Here, "m" can be changed corresponding to the length of the first direction d1 of the first partition plate 11, and "n" can be changed corresponding to the length of the second direction d2 of the first partition plate 11. In the embodiment, as described later, the lengths of the first direction d1 of each first partition plate 11 are different from each other, so the number of holes 110 arranged in the first direction d1 in each first partition plate 11 is different from each other. On the other hand, in the embodiment, the lengths of the second direction d2 of each first partition plate 11 are the same, so the number of holes 110 arranged in the second direction d2 in each first partition plate 11 is the same.
[0056] In an embodiment, if Figure 3 As shown, the lengths l1 of the first direction d1 of the plurality of first partition plates 11 are different from each other. Here, the first direction d1 is a direction for controlling the directivity of the sound wave W1. In addition, the plurality of first partition plates 11 are arranged so as to extend from one side ( Figure 3 ) towards the other side ( Figure 3In other words, the plurality of first partition plates 11 are arranged in such a manner that the more directional a side is desired in the first direction d1 of the sound wave W1, the less the number of overlaps in the traveling direction of the sound wave W1. In other words, the plurality of first partition plates 11 are arranged in such a manner that the length l1 of the first direction d1 becomes longer from the upper side toward the lower side in the traveling direction of the sound wave W1. That is, among the plurality of first partition plates 11, the length l1 of the first direction d1 of the first partition plate 11 located at the top in the traveling direction of the sound wave W1 is the shortest, and the length l1 of the first direction d1 of the first partition plate 11 located at the bottom is the longest.
[0057] Here, use Figure 4 The control of the directivity of the acoustic wave W1 in the first direction d1 by the acoustic lens 1 is described below. Figure 4 In FIG. 1 , the holes 110 are not shown. Figure 4 In the embodiment, the sound wave W1 passing through each first partition plate 11 actually passes through each hole 110. Figure 4 As shown, the sound wave W1 passes through the holes 110 of the first partition plates 11 and is radiated to the outside (the atmosphere).
[0058] Here, if Figure 4 As shown, in the acoustic lens 1 , the directivity in the first direction d1 is controlled by changing the length of the path through which the sound wave W1 passes.
[0059] Specifically, the sound wave W1 emitted from the speaker 2 and reaching the ear of the user U2 sitting in the seat 3A is as shown by the single-dot chain line. The more the first partition plate 11 overlaps, the farther it is from one side in the first direction d1 ( Figure 4 Therefore, the length of the path of the sound wave W1 on one side in the first direction d1 is less than the length of the path of the sound wave W1 on the side where the first partition plate 11 overlaps less, that is, the other side in the first direction d1 ( Figure 4 The difference in the length of the path of the sound wave W1 (on the left side in the figure) becomes larger, the difference in the arrival time of the sound wave W1 reaching the ear of the user U2 becomes larger, and the dissipation of the sound wave W1 becomes larger.
[0060] In contrast, the sound wave W1 emitted from the speaker 2 and reaching the ear of the user U1 sitting on the seat 3 is as shown by the dotted line. Since the user U1 is located on one side in the first direction d1 where the overlap of the first partition plate 11 is large, the overlap of the first partition plate 11 has almost no effect on the path of the sound wave W1. Therefore, there is almost no difference between the length of the path of the sound wave W1 on one side in the first direction d1 and the length of the path of the sound wave W1 on the other side in the first direction d1, so the difference in the arrival time of the sound wave W1 reaching the ear of the user U1 is small, and the influence of the dissipation of the sound wave W1 is small.
[0061] Therefore, the sound pressure level of the sound wave W1 reaching the ear of the user U2 is suppressed relative to the sound pressure level of the sound wave W1 reaching the ear of the user U1 , so that the directivity is biased toward one side in the first direction d1 .
[0062] [2. Advantages]
[0063] The advantages of the acoustic lens 1 and the speaker system 100 of the embodiment are described below. As described above, in the acoustic lens 1 of the embodiment, the lengths of the first direction d1 of the plurality of first partition plates 11 spaced apart and arranged in the traveling direction of the sound wave W1 are made different from each other. Therefore, in the acoustic lens 1 of the embodiment, the length of the path through which the sound wave W1 passes can be adjusted according to the number of holes 110 through which the sound wave W1 passes, so there is an advantage that the directivity of the sound wave W1 (here, the directivity in the first direction d1 of the sound wave W1) can be easily controlled.
[0064] In the embodiment, the first direction d1 is set to the horizontal direction, and the acoustic lens 1 can control the horizontal directivity of the sound wave W1. Therefore, the acoustic lens 1 of the embodiment and the speaker system 100 using the acoustic lens 1 can solve the technical problems of the speaker system 200 of the comparative example.
[0065] For example, Figure 2 As shown, the speaker system 100 is respectively arranged near the left ear and the right ear of the user U1 sitting on the seat 3, and the acoustic lens 1 is arranged so that the sound wave W1 has a directivity biased toward the user U1 in the horizontal direction (first direction d1). In this case, since the sound wave W1 emitted by the speaker 2 is radiated in a manner of having a directivity biased toward the user U1 in the horizontal direction through the acoustic lens 1, the sound is not easily leaked to the user U2 sitting on the seat 3A next to the seat 3.
[0066] Similarly, the speaker system 100 is respectively arranged near the left ear and the right ear of the user U2 sitting on the seat 3A next to the seat 3, and the acoustic lens 1 is arranged in such a manner that the sound wave W1 has a directivity that is biased toward the user U2 in the horizontal direction (first direction d1). In this case, since the sound wave W1 emitted by the speaker 2 is radiated in such a manner that the directivity is biased toward the user U2 in the horizontal direction through the acoustic lens 1, the sound is not easily leaked to the user U1 sitting on the seat 3.
[0067] As described above, the acoustic lens 1 of the embodiment and the speaker system 100 using the acoustic lens 1 have the advantage of being able to easily suppress sound leakage to persons other than the target user U1 (or user U2 ).
[0068] (Other embodiments)
[0069] As mentioned above, although embodiment was described, this disclosure is not limited to the said embodiment.
[0070] <First Modification>
[0071] Figure 5 1 is a schematic diagram showing the structure of an acoustic lens 1A of a first variant of the embodiment. The acoustic lens 1A of the first variant is different from the acoustic lens 1 of the embodiment in that the diameter R1 of the plurality of holes 110 decreases as they move away from the speaker 2 in the direction of travel of the sound wave W1 (in other words, in the thickness direction of the first partition plate 11).
[0072] Specifically, the diameter R1 of each hole 110 of the first partition plate 11 located at the bottom in the direction of travel of the sound wave W1 is the largest, and the diameter R1 of each hole 110 of the first partition plate 11 located at the top is the smallest. Here, in any first partition plate 11, the ratio of the total area of the plurality of holes 110 to the area of the first partition plate 11 is defined as the aperture ratio. Therefore, in the acoustic lens 1A of the first modified example, it can be said that the aperture ratio of each of the plurality of first partition plates 11 decreases as it moves away from the speaker 2 in the direction of travel of the sound wave W1.
[0073] As described above, in the acoustic lens 1A of the first variant, the opening ratio of each of the plurality of first partition plates 11 decreases as the distance from the speaker 2 in the traveling direction of the sound wave W1 increases. Therefore, in the acoustic lens 1A of the first variant, the greater the number of holes 110 passing through, the longer the length of the path through which the sound wave W1 passes. Therefore, in the acoustic lens 1A of the first variant, the sound wave W1 is controlled to be more biased toward one side in the first direction d1 ( Figure 5 The directivity of the sound wave W1 is easy to become sharp.
[0074] <Second Modification>
[0075] Figure 6 1 is a schematic diagram showing a configuration of an acoustic lens 1B according to a second modification of the embodiment. The acoustic lens 1B according to the second modification is different from the acoustic lens 1 according to the embodiment in that a plurality of second partition plates 12 are further provided.
[0076] Each second partition plate 12 is a flat plate and is a member that is difficult to vibrate. The material constituting each second partition plate 12 is, for example, wood, resin, metal, or ceramic, etc., and is not particularly limited. Figure 6As shown in the figure, the plurality of first partition plates 11 are overlapped in the traveling direction of the sound wave W1 and arranged at intervals. Specifically, the plurality of second partition plates 12 are arranged in the traveling direction of the sound wave W1 in a manner that the first partition plates 11 and the second partition plates 12 are alternately arranged at intervals. In addition, each second partition plate 12 can be supported by a frame-shaped component or a spacer not shown in the figure in the same manner as each first partition plate 11.
[0077] The plurality of second partition plates 12 are respectively Figure 6 As shown, there are a plurality of holes 120 through which the sound wave W1 passes. Figure 6 In FIG. 1 , only the plurality of holes 120 of the second partition plate 12 located at the top in the traveling direction of the sound wave W1 (in other words, the thickness direction of the second partition plate 12) are shown, and the plurality of holes 120 of the other second partition plates 12 are omitted. Figure 6 In the figure, the plurality of holes 110 of each first partition plate 11 are omitted.
[0078] In the second modification, the hole 120 is circular in plan view (i.e., viewed from the traveling direction of the sound wave W1), and penetrates the second partition plate 12 in the thickness direction (i.e., the traveling direction of the sound wave W1). In addition, in the second modification, in each second partition plate 12, a plurality of holes 120 are arranged in a matrix of p (p is a natural number) arranged in the first direction d1 and q (q is a natural number) arranged in the second direction d2.
[0079] Here, "p" can be changed corresponding to the length of the second partition plate 12 in the first direction d1, and "q" can be changed corresponding to the length of the second partition plate 12 in the second direction d2. In the second modified example, as described later, the length of the first direction d1 and the length of the second direction d2 of each second partition plate 12 are different from each other, so the number of holes 120 arranged in the first direction d1 in each second partition plate 12 is different from each other, and the number of holes 120 arranged in the second direction d2 is also different from each other.
[0080] In the second variant, Figure 6As shown, the length l1 of each of the plurality of second partition plates 12 in the first direction d1 is different from each other. In addition, the length l2 of each of the plurality of second partition plates 12 in the second direction d2 intersecting the first direction d1 is different from each other. Here, the second direction d2 is the same as the first direction d1, and is a direction for controlling the directivity of the sound wave W1. And, the plurality of second partition plates 12 are arranged in such a manner that the number of overlaps in the traveling direction of the sound wave W1 decreases as they move away from the center of the second direction d2. In other words, the plurality of second partition plates 12 are arranged in such a manner that the more the side with directivity is desired in the second direction d2 of the sound wave W1, the more the number of overlaps in the traveling direction of the sound wave W1 increases. In other words, the plurality of second partition plates 12 are arranged in such a manner that the length l2 of the second direction d2 decreases as they move from the upper side to the lower side in the traveling direction of the sound wave W1. That is, among the plurality of second partition plates 12 , the second partition plate 12 located uppermost in the traveling direction of the sound wave W1 has the longest length l2 in the second direction d2 , and the second partition plate 12 located lowermost has the shortest length l2 in the second direction d2 .
[0081] Here, use Figure 7 Control of the directivity of the acoustic wave W1 in the second direction d2 by the acoustic lens 1B according to the second modification example will be described. Figure 7 1B is an explanatory diagram of the directivity of the acoustic lens 1B according to the second modified example of the embodiment. Figure 7 In FIG. 1 , the illustration of each first partition plate 11 and the illustration of each hole 120 of each second partition plate 12 are omitted. Figure 7 In the figure, the sound wave W1 passing through each second partition plate 12 actually passes through each hole 110 of each first partition plate 11 and each hole 120 of each second partition plate 12.
[0082] Here, if Figure 7 As shown, in the acoustic lens 1B, the directivity in the second direction d2 is controlled by changing the length of the path through which the sound wave W1 passes.
[0083] Specifically, the path of the sound wave W1 emitted from the speaker 2 is longer in the center in the second direction d2 where the overlap of the second partition plate 12 is greater, and longer in the end in the second direction d2 where the overlap of the second partition plate 12 is less ( Figure 7 Therefore, the wavefront of the sound wave W1 can be virtually regarded as Figure 7 A concave wavefront as shown by the single-dot chain line.
[0084] Thus, the acoustic lens 1B has the effect of concentrating the sound wave W1 at the virtual point p, just as a parabolic antenna concentrates radio waves at a focal point. Therefore, the sound pressure level at the virtual point p on the central axis of the acoustic lens 1B becomes high, and the sound pressure level at a position deviating from the central axis is suppressed, so that the directivity becomes biased toward the center in the second direction d2. As described above, in the acoustic lens 1B of the second modified example, by making the lengths of the second direction d2 of the plurality of second partition plates 12 spaced apart and arranged in the traveling direction of the sound wave W1 different from each other, there is an advantage that the directivity of the sound wave W1 (here, the directivity of the sound wave W1 in the second direction d2) can be easily controlled.
[0085] In the second modification, the second direction d2 is set as the vertical direction, and the acoustic lens 1B can control the vertical directivity of the sound wave W1. Therefore, the acoustic lens 1B of the second modification and the speaker system 100 using the acoustic lens 1B can solve the technical problems of the speaker system 200 of the comparative example.
[0086] For example, with Figure 2 In the example of use shown, the speaker system 100 using the acoustic lens 1B is arranged near the left ear and the right ear of the user U1 sitting in the seat 3. In this case, the sound wave W1 emitted by the speaker 2 is radiated through the acoustic lens 1B without being diffused in the vertical direction and being oriented toward the front of the user U1, so that the sound wave W1 is not easy to detour to the rear of the seat 3, and the sound is not easy to leak to the user sitting in the seat behind the seat 3.
[0087] In addition, in the acoustic lens 1B of the second variant, as in the first variant, the opening ratio of each first partition plate 11 can be reduced as the distance from the speaker 2 is increased in the direction of travel of the sound wave W1. Similarly, the opening ratio of each second partition plate 12 can be reduced as the distance from the speaker 2 is increased in the direction of travel of the sound wave W1. The opening ratio of the second partition plate 12 is defined by the ratio of the total area of the plurality of holes 120 to the area of the second partition plate 12 in any second partition plate 12. In this structure, there is an advantage that the directivity of the sound wave W1 can be easily sharpened compared to the case where the opening ratio of each first partition plate 11 and each second partition plate 12 is not changed.
[0088] <Third Modification>
[0089] Figure 81 is a schematic diagram showing the structure of an acoustic lens 1C of the third variant of the embodiment. The acoustic lens 1C of the third variant is different from the acoustic lens 1 of the embodiment in that the first direction d1 is set as the vertical direction, and is configured in such a way that the number of overlaps in the traveling direction of the sound wave W1 decreases as it moves away from the center in the first direction d1. That is, the acoustic lens 1C of the third variant is different from the acoustic lens 1 of the embodiment which is configured to control the directivity of the sound wave W1 mainly in the vertical direction in that it is configured to control the directivity of the sound wave W1 mainly in the horizontal direction.
[0090] Specifically, in the third variant, Figure 8 As shown, the length l1 of each of the plurality of first partitions 11 in the first direction d1 is different from each other. Furthermore, the plurality of first partitions 11 are arranged in such a manner that the number of overlaps in the traveling direction of the sound wave W1 decreases as they are away from the center of the first direction d1. In other words, the plurality of first partitions 11 are arranged in such a manner that the more directional the side is desired to be in the first direction d1 of the sound wave W1, the more overlaps in the traveling direction of the sound wave W1. In other words, the plurality of first partitions 11 are arranged in such a manner that the length l1 of the first direction d1 increases from the upper side toward the lower side in the traveling direction of the sound wave W1. That is, the length l1 of the first direction d1 of the first partition 11 located at the top in the traveling direction of the sound wave W1 among the plurality of first partitions 11 is the shortest, and the length l1 of the first direction d1 of the first partition 11 located at the bottom is the longest.
[0091] As described above, in the third modification, the first direction d1 is set as the vertical direction, and the acoustic lens 1C can control the directivity of the sound wave W1 in the vertical direction.
[0092] In the acoustic lens 1C of the third modification, similarly to the first modification, the opening ratio of each first partition plate 11 can be reduced as the distance from the speaker 2 in the traveling direction of the sound wave W1 increases. In this structure, there is an advantage that the directivity of the sound wave W1 is easily sharpened compared to the case where the opening ratio of each first partition plate 11 is not changed.
[0093] <Other Modifications>
[0094] In the above-mentioned embodiment and each of the above-mentioned variations, the holes 110 and 120 adjacent to each other in the traveling direction of the sound wave W1 may be arranged in a manner that they do not overlap with each other when viewed from the traveling direction of the sound wave W1. In other words, at least a portion of the plurality of holes 110 and 120 may not overlap with each other in the traveling direction of the sound wave W1. In this structure, since the path through which the sound wave W1 passes can be lengthened, there is an advantage that the directivity of the sound wave W1 can be easily sharpened.
[0095] Furthermore, in the above-described embodiment and each of the above-described modifications, the shape of the holes 110 and 120 in plan view is not limited to a circle, and may be, for example, a rectangle or a polygon.
[0096] In addition, the present disclosure also includes forms obtained by implementing various modifications conceived by technical personnel in the field of technology to the embodiments and various modified examples, or forms achieved by arbitrarily combining the components and functions described in the embodiments and various modified examples without departing from the main scope of the present disclosure.
[0097] Industrial Applicability
[0098] The present disclosure is useful as a component for controlling the directivity of sound waves emitted from a speaker.
[0099] Description of Reference Numerals
[0100] 1.1A, 1B, 1C Acoustic lens
[0101] 11 1st partition plate
[0102] 110 holes
[0103] 12 Second partition plate
[0104] 120 holes
[0105] 2 Speakers
[0106] 3. 3A Seat
[0107] 31, 31A Headrest
[0108] 100 Speaker System
[0109] 200 Comparative Example Speaker System
[0110] d1 1st direction
[0111] d2 2nd direction
[0112] l1, l2 length
[0113] p Virtual point
[0114] R1 diameter
[0115] U1, U2 users
[0116] W1 Sound Wave
Claims
1. An acoustic lens, characterized in that: A plurality of first partition plates are arranged at intervals in the direction of travel of sound waves emitted from the speaker; The plurality of first partition plates respectively have a plurality of holes through which the sound waves pass; The lengths of the plurality of first partition plates in the first direction are different from each other.
2. The acoustic lens according to claim 1, wherein The plurality of first partition plates are arranged such that the number of the first partition plates overlapping each other in the traveling direction of the sound wave decreases as the number of the first partition plates increases from one direction toward the other direction in the first direction.
3. The acoustic lens according to claim 1 or 2, wherein: Also provided are a plurality of second partition plates which overlap with the plurality of first partition plates in the traveling direction of the sound wave and are arranged at intervals; The plurality of second partition plates respectively have a plurality of holes through which the sound waves pass; The second partition plates have different lengths in a second direction intersecting the first direction.
4. The acoustic lens according to claim 3, wherein: The plurality of second partition plates are arranged such that the number of the second partition plates overlapping each other in the traveling direction of the sound wave decreases as they are separated from the center in the second direction.
5. The acoustic lens according to claim 3, wherein: The first direction and the second direction are orthogonal to each other.
6. The acoustic lens according to claim 1 or 2, wherein: The diameters of the plurality of holes decrease as they are farther away from the speaker in the traveling direction of the sound wave.
7. The acoustic lens according to claim 1 or 2, characterized in that: At least a portion of the plurality of holes does not overlap with each other in a traveling direction of the sound wave.
8. A speaker system, characterized in that: have: The acoustic lens according to claim 1 or 2; and The speaker emits the sound wave toward the acoustic lens.