Diaphragm and speaker unit

Abstract

To suppress generation of a peak dip in a diaphragm.SOLUTION: A diaphragm 1 is formed in a predetermined shape in which a length of one axial direction and a length in the other axial direction are different in the two axial direction which are orthogonal in a planar view and both sides in a length direction which is one axial direction consist of curves. The diaphragm 1 comprises a first reinforcement part 3 which extends in the length direction, and a second reinforcement part 4 which is mesh-like unevenness provided adjacently to the first reinforcement part 3 in a width direction. Insect wings are imitated on the second reinforcement part 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a diaphragm and a speaker unit including the diaphragm. [Background technology]

[0002] Diaphragms used in speaker units come in a variety of shapes, from the typical perfect circle to irregular shapes that are compatible with TVs, laptops, and other devices with limited installation space. Irregular shapes include oval and track shapes (see Figure 28). Irregular-shaped diaphragms have a large aspect ratio between the long and short sides, and to make the rigidity of the entire diaphragm uniform, reinforcing ribs are provided in the long direction, improving characteristics (see Figure 29). Note that all of the above diaphragm shapes are viewed in plan. However, with linear reinforcing ribs, it is difficult to increase the rigidity around the ribs, and if the width of the ribs is increased, the weight balance in the short direction is disrupted, resulting in large peak / dip characteristics.

[0003] To solve the above problems, Patent Document 1 describes a diaphragm with wide convex ribs (see Figure 30). However, a slender diaphragm with a large aspect ratio disrupts the weight balance in the short direction, making it prone to rolling gaps and resulting in peak-dip characteristics. Patent Document 1 also describes a diaphragm with a dragonfly vein pattern on the convex ribs in order to disperse split resonances in the high-frequency characteristics (see Figure 31). However, this further increases the weight in the long direction, and the vein pattern reduces the effectiveness of the convex ribs. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-125869 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, the conventional technology has a problem in that peaks and dips occur.

[0006] An object of the present invention is to suppress the occurrence of peaks and dips in the diaphragm. [Means for solving the problem]

[0007] The vibration plate of the first invention is a vibration plate of a predetermined shape in which, in a plan view, the length in one axial direction is different from the length in the other axial direction in two perpendicular axial directions, and both sides of the longitudinal direction, which is one of the axial directions, are formed by curves, and is characterized by having a first reinforcing portion extending along the longitudinal direction, and a second reinforcing portion which is a mesh-like unevenness arranged adjacent to the first reinforcing portion in the lateral direction.

[0008] In the present invention, a first reinforcing portion extending along the longitudinal direction and a second reinforcing portion having a mesh-like irregularity adjacent to the first reinforcing portion are provided. This (1) suppresses flapping of the edges provided on the diaphragm. In addition, (2) the first reinforcing portion increases the overall rigidity, and the second reinforcing portion efficiently disperses resonance peaks. According to the present invention, peak dips in the diaphragm are suppressed by (1) or (2).

[0009] A diaphragm according to a second aspect of the present invention is the diaphragm according to the first aspect of the present invention, wherein the second reinforcing portion is shaped like an insect wing.

[0010] The diaphragm of the third invention is characterized in that, in the diaphragm of the second invention, the second reinforcing portion is based on data measured from the actual shape of the insect's wing veins, or data of a Voronoi diagram simulating the insect's wing veins.

[0011] The vibration plate of the fourth invention is characterized in that, in the vibration plate of the first invention, the second reinforcing portion has a plurality of polygonal convex portions and a plurality of polygonal concave portions formed inside the convex portions by the convex portions, and one side of adjacent convex portions in the plurality of convex portions is part of both polygons.

[0012] A diaphragm of a fifth invention is the diaphragm of the first invention, characterized in that the second reinforcing portion spreads out radially from the center along the longitudinal direction.

[0013] A diaphragm of a sixth invention is the diaphragm of the first invention, characterized in that two of the second reinforcing portions are provided in the short-side direction, with the first reinforcing portion sandwiched between them.

[0014] A diaphragm according to a seventh aspect of the present invention is the diaphragm according to the sixth aspect of the present invention, characterized in that the mesh shapes of the two second reinforcing portions are different.

[0015] The diaphragm of the eighth invention is characterized in that, in the diaphragm of the sixth invention, the first reinforcing portion and the two second reinforcing portions are provided in pairs, sandwiching the center in the longitudinal direction.

[0016] A diaphragm according to a ninth aspect of the present invention is the diaphragm according to the eighth aspect of the present invention, wherein the two second reinforcing portions sandwiching the center in the longitudinal direction are point-symmetric with respect to the center.

[0017] A diaphragm of a tenth invention is characterized in that, in the diaphragm of the first invention, the width of the first reinforcing portion gradually narrows from the center in the longitudinal direction along the longitudinal direction.

[0018] A diaphragm of an eleventh invention is the diaphragm of the first invention, characterized in that the aspect ratio of the length in the longitudinal direction to the length in the lateral direction is 2:1 or more.

[0019] The speaker unit of the 12th invention is characterized by comprising a diaphragm of the first invention, a voice coil connected to an opening in the diaphragm, a dust cap connected to the voice coil, an edge connected to the outer periphery of the diaphragm, a frame to which the outer periphery of the edge is fixed, and a magnetic circuit having a magnetic gap in which the coil of the voice coil is arranged and fixed to the frame. [Effects of the Invention]

[0020] According to the present invention, peaks and dips in the diaphragm are suppressed. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 2 is a perspective view of a diaphragm according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of a diaphragm according to an embodiment of the present invention. [Figure 3] 1 is a perspective view of a diaphragm and the like according to an embodiment of the present invention. [Figure 4] 1 is a perspective view of a speaker unit according to an embodiment of the present invention. [Figure 5] FIG. 1 is a model diagram showing Comparative Example 1. [Figure 6] FIG. 10 is a model diagram showing Comparative Example 2. [Figure 7] FIG. 10 is a model diagram showing Comparative Example 3. [Figure 8] FIG. 1 is a model diagram illustrating an embodiment. [Figure 9] 1 is a graph showing frequency characteristics of an example and a comparative example 1. [Figure 10] 1(a) is a diagram showing the movement of the model of the example at 2300 Hz, and FIG. 1(b) is a diagram showing the movement of the model of the comparative example 1 at 2300 Hz. [Figure 11] 1(a) is a diagram showing the movement of the model of the example at 3200 Hz, and FIG. 1(b) is a diagram showing the movement of the model of the comparative example 1 at 3200 Hz. [Figure 12]1(a) is a diagram showing the movement of the model of the example at 9200 Hz, and FIG. 1(b) is a diagram showing the movement of the model of the comparative example 1 at 9200 Hz. [Figure 13] 10 is a graph showing frequency characteristics of an example, comparative example 2, and comparative example 3. [Figure 14] 1(a) is a diagram showing the movement of the model of the example at 2500 Hz, and FIG. 1(b) is a diagram showing the movement of the model of the comparative example 2 at 2500 Hz. [Figure 15] 1(a) is a diagram showing the movement of the model of the example at 3700 Hz, and FIG. 1(b) is a diagram showing the movement of the model of the comparative example 2 at 3700 Hz. [Figure 16] 1(a) is a diagram showing the wavefront in the longitudinal direction of Example 1 at 2300 Hz, and FIG. 1(b) is a diagram showing the wavefront in the longitudinal direction of Comparative Example 1 at 2300 Hz. [Figure 17] 17(a) is a diagram showing the sound pressure distribution in the longitudinal direction of the example at 2300 Hz, and FIG. 17(b) is a diagram showing the sound pressure distribution in the longitudinal direction of the comparative example 1 at 2300 Hz. [Figure 18] 1(a) is a diagram showing the longitudinal wavefront of Example at 3200 Hz, and FIG. 1(b) is a diagram showing the longitudinal wavefront of Comparative Example 1 at 3200 Hz. [Figure 19] 1(a) is a diagram showing the sound pressure distribution in the longitudinal direction of the example at 3200 Hz, and FIG. 1(b) is a diagram showing the sound pressure distribution in the longitudinal direction of the comparative example 1 at 3200 Hz. [Figure 20] 1(a) is a diagram showing the longitudinal wavefront of Example at 9200 Hz, and FIG. 1(b) is a diagram showing the longitudinal wavefront of Comparative Example 1 at 9200 Hz. [Figure 21] 1(a) is a diagram showing the sound pressure distribution in the longitudinal direction of the example at 9200 Hz, and FIG. 1(b) is a diagram showing the sound pressure distribution in the longitudinal direction of the comparative example 1 at 9200 Hz. [Figure 22] 1(a) is a diagram showing the wavefront in the longitudinal direction of the example at 20,000 Hz, and FIG. 1(b) is a diagram showing the wavefront in the longitudinal direction of the comparative example 1 at 20,000 Hz. [Figure 23]1(a) is a diagram showing the sound pressure distribution in the longitudinal direction of the example at 20,000 Hz, and FIG. 1(b) is a diagram showing the sound pressure distribution in the longitudinal direction of the comparative example 1 at 20,000 Hz. [Figure 24] 1(a) is a diagram showing the longitudinal wavefront of Example at 2500 Hz, and FIG. 1(b) is a diagram showing the longitudinal wavefront of Comparative Example 2 at 2500 Hz. [Figure 25] 1(a) is a diagram showing the sound pressure distribution in the longitudinal direction of the example at 2500 Hz, and FIG. 1(b) is a diagram showing the sound pressure distribution in the longitudinal direction of the comparative example 2 at 2500 Hz. [Figure 26] 1(a) is a diagram showing the longitudinal wavefront of Example at 3700 Hz, and FIG. 1(b) is a diagram showing the longitudinal wavefront of Comparative Example 2 at 3700 Hz. [Figure 27] 1(a) is a diagram showing the sound pressure distribution in the longitudinal direction of the example at 3700 Hz, and FIG. 1(b) is a diagram showing the sound pressure distribution in the longitudinal direction of the comparative example 2 at 3700 Hz. [Figure 28] FIG. 10 is a perspective view showing a conventional diaphragm. [Figure 29] FIG. 10 is a perspective view showing a conventional diaphragm. [Figure 30] FIG. 1 is a perspective view showing a diaphragm described in Patent Document 1. [Figure 31] FIG. 1 is a perspective view showing a diaphragm described in Patent Document 1. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an embodiment of the present invention will be described. Note that the numerical values etc. described below are examples and are not limited to these numerical values etc. Fig. 1 is a perspective view of a diaphragm 1 according to an embodiment of the present invention. Fig. 2 is a plan view of the diaphragm 1 according to an embodiment of the present invention. Note that in this embodiment, only the cone paper main body is defined as the diaphragm 1.

[0023] The diaphragm 1 includes an opening 2, a first reinforcing portion 3, a second reinforcing portion 4, etc. As shown in the figure, the diaphragm 1 has a predetermined shape in which, in a plan view, the length in one axial direction is different from the length in the other axial direction, and both sides of the longitudinal direction, which is one axial direction, are formed by curves. Specifically, the diaphragm 1 has a track shape (predetermined shape) in a plan view. Here, the "track shape" refers to a shape formed by two parallel lines of equal length and two semicircles, and is a shape used in so-called athletics stadiums. Note that the diaphragm 1 may also have an elliptical shape (predetermined shape) in a plan view. Here, the "elliptical shape" includes a substantially elliptical shape that is close to an elliptical shape, and the "track shape" includes a substantially track shape that is close to a track shape.

[0024] The length of the diaphragm 1 in the longitudinal direction (one axial direction) is, for example, 59.6 mm. The length of the diaphragm 1 in the lateral direction (the other axial direction) perpendicular to the longitudinal direction is, for example, 15.1 mm. Therefore, the aspect ratio between the longitudinal and lateral directions of the diaphragm 1 is approximately 4:1. Note that the length in the longitudinal direction and the length in the lateral direction are not limited to the above example. However, as described above, the length in the longitudinal direction and the length in the lateral direction of the diaphragm 1 are different, and the aspect ratio a:b between the longitudinal and lateral directions is a>1 when b=1. Note that the aspect ratio between the longitudinal and lateral directions of the diaphragm 1 will be described later.

[0025] Diaphragm 1 has an opening 2 in the center. Opening 2 is track-shaped. Note that opening 2 is not limited to a track shape and may be, for example, elliptical. Diaphragm 1 is formed with a convex curved surface extending from opening 2 (center) to the outer periphery.

[0026] The diaphragm 1 is provided with first reinforcing portions 3 extending along the longitudinal direction. The first reinforcing portions 3 are so-called ribs. Two first reinforcing portions 3 are provided in the longitudinal direction, sandwiching an opening 2 therebetween. The first reinforcing portions 3 are provided at symmetrical positions (symmetrical positions with the short-side direction as the axis of symmetry) across the opening 2. Note that the first reinforcing portions 3 may also be provided at asymmetrical positions (symmetrical positions with the short-side direction as the axis of symmetry) across the opening 2.

[0027] The width of the first reinforcing part 3 gradually narrows from the center along the longitudinal direction (from the opening 2 outward in the longitudinal direction). That is, the shape of the first reinforcing part 3 is approximately triangular in plan view. The width of the first reinforcing part 3 may be constant and may extend approximately linearly in the longitudinal direction in plan view. That is, the shape of the first reinforcing part 3 may be approximately rectangular in plan view. Furthermore, the first reinforcing part 3 may have a portion extending along the longitudinal direction, and for example, a substantially U-shaped rib may be provided at the end opposite the opening 2 to sandwich the portion extending along the longitudinal direction.

[0028] The diaphragm 1 also has second reinforcing portions 4 (4a, 4b) adjacent to the first reinforcing portion 3 in the lateral direction. The second reinforcing portions 4 have a mesh-like unevenness. The second reinforcing portions 4 radiate from the center along the longitudinal direction (from the opening 2 toward the outside in the longitudinal direction). Two second reinforcing portions 4 are provided in the lateral direction, sandwiching the first reinforcing portion 3 therebetween. The two second reinforcing portions 4a, 4b sandwiching the first reinforcing portion 3 have different mesh shapes. The two second reinforcing portions 4a, 4b are provided on either side of the opening 2 (the center in the longitudinal direction). The two second reinforcing portions 4a are point-symmetric with respect to the center of the diaphragm 1. Similarly, the two second reinforcing portions 4b are point-symmetric with respect to the center of the diaphragm 1. The second reinforcing portions 4 do not overlap the first reinforcing portion 3. In other words, the first reinforcing portion 3 and the second reinforcing portion 4 are arranged independently.

[0029] The width of the convex portion in the second reinforcing portion 4 is, for example, 0.3 mm. The height of the convex portion is, for example, 0.5 mm. However, the width and height of the convex portion are not limited to these values.

[0030] The second reinforcing portion 4 is modeled after an insect's wing. The unevenness of an insect's wing can be modeled using data obtained by measuring the shape of the insect's actual wing veins. For example, by identifying and digitizing the positions of the intersections of the vein lines in two dimensions from a photograph of the insect and connecting these intersections, it is possible to recreate the unevenness of the actual wing veins. In actual wing veins, the distances between the intersections of the vein lines vary widely. The wing veins form an unevenness that is a series of numerous polygons (mainly triangles, squares, or pentagons) of various sizes and shapes. The unevenness of the vein lines realizes a structure that combines the strength and lightness required for insect wings to fly.

[0031] However, the dimensions of the irregularities used in the diaphragm do not need to match the dimensions of the actual insect wing veins, and can be enlarged several times. Since the actual area of an insect wing is small, it is appropriate to enlarge the irregularities while maintaining the relative size ratio of the irregularities. Furthermore, the same vein shape of a predetermined area can be repeatedly arranged multiple times to form irregularities that reinforce the diaphragm. Note that the irregularities formed by the insect wing veins can be formed by using the vein parts as thick convex parts and the membrane parts surrounded by the vein parts as thin concave parts, and it is not necessary to accurately imitate the thickness dimensions.

[0032] The concaves and convexes are formed by arranging the same wing vein shape repeatedly in a predetermined area. The concaves and convexes are formed based on data obtained by measuring the wing vein shape of an actual dragonfly, for example. However, the concaves and convexes are not limited to dragonflies, and may also imitate the wings of other insects such as cicadas, butterflies, rhinoceros beetles, and ladybugs.

[0033] Furthermore, based on the observation that the unevenness of insect wings is similar to a Voronoi diagram, it is possible to create unevenness that mimics the wing veins of an insect from the data of a Voronoi diagram that has been drawn. A Voronoi diagram is created by taking several points (generator points) on a plane, connecting these points with lines, drawing perpendicular bisectors of each side of the resulting triangle, and erasing the lines that were initially drawn. A Voronoi diagram can be said to be a diagram obtained by dividing the generator points arranged on a plane based on which other generator points they are closest to. Therefore, it is possible to draw unevenness that mimics the wing veins of an insect using the perpendicular bisectors connected by the Voronoi diagram. The unevenness may be formed based on data of a Voronoi diagram that mimics the wing veins of an insect.

[0034] The wing veins that form the irregularities of insect wings only have body fluids flowing through them when the wings are extended, and they dry up after the wings are formed, leaving the wing veins hollow. This contributes to a structure that combines the strength and lightness required for wings. Therefore, a diaphragm 1 that forms irregularities that mimic insect wings may have a hollow space formed inside that mimics the insect's wing veins.

[0035] For example, in a ruggedness that resembles an insect's wing, the density of the diaphragm material inside the thick convex portions may be lower than the density of the diaphragm material inside the thin concave portions. Also, in a diaphragm formed by bonding a front material and a back material together, the thin concave portions may be formed by bonding together, and a hollow space where the front material and the back material are not bonded together may be provided inside the thick convex portions.

[0036] Here, "insect wings" refer to the wings of insects, which are thin extensions of the exoskeleton on their backs and are made of chitin. "Venae" refer to the thickened chitinous veins that spread across the wings like leaf veins to support the membranous wings.

[0037] The second reinforcing part 4 does not have to resemble insect wings. For example, the second reinforcing part 4 may have a plurality of polygonal convex parts and a plurality of polygonal concave parts formed inside the convex parts by the convex parts, and one side of adjacent convex parts may form part of both polygons. Other shapes of the second reinforcing part 4 will be described later.

[0038] FIG. 3 is a perspective view of a diaphragm 1 and other components according to an embodiment of the present invention. FIG. 4 is a perspective view of a speaker unit 101 according to an embodiment of the present invention. The speaker unit 101 includes a diaphragm 1, a voice coil, a dust cap 6, an edge 5, a frame 7, a magnetic circuit, and the like. The voice coil is connected to an opening 2 of the diaphragm 1. The voice coil has a cylindrical bobbin and a coil wound around the bobbin. The dust cap 6 is connected to the voice coil. Specifically, the dust cap 6 is attached to the tip of the bobbin with, for example, an adhesive. The edge 5 is connected to the outer periphery of the diaphragm 1 and supports the diaphragm 1 so that it can vibrate. The material of the edge 5 is, for example, NBR60°.

[0039] The frame 7 is fixed to the outer periphery of the edge 5. The magnetic circuit is fixed to the frame 7. The magnetic circuit has a magnetic gap in which the coil of the voice coil is placed. The magnetic circuit is composed of a top plate, a pole, and a magnet. The top plate is annular and fixed to the frame 7. The pole is cylindrical and has a center pole that is inserted into a circular opening formed in the center of the top plate, and a flat underplate. The magnet is annular.

[0040] The characteristics of the diaphragm 1 according to this embodiment will be described below in comparison with other examples. FIG. 5 is a model diagram showing a diaphragm (Comparative Example 1) in which only the first reinforcing portion 3 (straight reinforcing ribs) is provided on the diaphragm 1, and the second reinforcing portion 4 is not provided. FIG. 6 is a model diagram showing a diaphragm (Comparative Example 2) in which the first reinforcing portion 3 is not provided on the diaphragm 1, and a wide-ranging second reinforcing portion 4 (uneven vein-patterned ribs) is provided. FIG. 7 is a model diagram showing a diaphragm (Comparative Example 3) in which the second reinforcing portion 4 of the diaphragm 1 is provided with unevenness (uneven vein-patterned ribs) on the convex reinforcing portion (convex ribs), similar to the diaphragms shown in FIGS. 27 to 32 of JP 2021-125869 A. FIG. 8 is a model diagram showing a diaphragm 1 (Example) according to this embodiment. A voice coil and a damper of a predetermined shape are arranged on the diaphragm shown in FIGS. 5 to 8 and modeled. The results of acoustic analysis using the boundary element method (BEM) are shown below. In Comparative Examples 1 to 3 and the Example, calculations were performed under the same analysis conditions (driving force: 1 N, microphone distance: 500 mm).

[0041] FIG. 9 is a graph showing the frequency characteristics of the Example and Comparative Example 1. FIG. 10(a) shows the movement of the Example model at 2300 Hz. FIG. 10(b) shows the movement of the Comparative Example 1 model at 2300 Hz. In Comparative Example 1, due to insufficient rigidity around the linear reinforcing ribs, the edge flutters significantly, resulting in peak and dip characteristics. In contrast, in the Example, the second reinforcing portion (the uneven vein-patterned rib) is disposed around the first reinforcing portion (the linear reinforcing rib), resulting in no edge flutter and suppressed peak and dip characteristics. FIG. 11(a) shows the movement of the Example model at 3200 Hz. FIG. 11(b) shows the movement of the Comparative Example 1 model at 3200 Hz. In Comparative Example 1, an out-of-phase mode in the longitudinal direction is observed, resulting in a large dip. In contrast, such a dip does not occur in the Example. FIG. 12(a) shows the movement of the Example model at 9200 Hz. Figure 12(b) shows the movement of the model of Comparative Example 1 at 9200 Hz. In Comparative Example 1, flapping in the longitudinal direction is observed. On the other hand, in the example, the overall rigidity is increased, and the second reinforcing part (the uneven vein pattern rib) efficiently distributes the resonance peak, resulting in characteristics with fewer peak dips.

[0042] FIG. 13 is a graph showing the frequency characteristics of the Example, Comparative Example 2, and Comparative Example 3. FIG. 14(a) shows the movement of the Example model at 2500 Hz. FIG. 14(b) shows the movement of the Comparative Example 2 model at 2500 Hz. For a slender shape with a large aspect ratio, such as approximately 4:1, there is a limit to the longitudinal rigidity enhancement achieved by the uneven vein-pattern ribs alone, as in Comparative Example 2. Consequently, edge flapping is observed, resulting in a large dip. Similarly, in Comparative Example 2, the vein-pattern ribs are arranged on top of the convex ribs, reducing the effect of the convex ribs. In contrast, such a phenomenon is not observed in the Example. FIG. 15(a) shows the movement of the Example model at 3700 Hz. FIG. 15(b) shows the movement of the Comparative Example 2 model at 3700 Hz. In Comparative Example 2, the flapping of the diaphragm results in significant edge movement and a resonance peak. In contrast, such a phenomenon is not observed in the Example.

[0043] Fig. 16(a) is a diagram showing the longitudinal wavefront of the example at 2300 Hz. Fig. 16(b) is a diagram showing the longitudinal wavefront of comparative example 1 at 2300 Hz. Fig. 17(a) is a diagram showing the longitudinal sound pressure distribution of the example at 2300 Hz. Fig. 17(b) is a diagram showing the longitudinal sound pressure distribution of comparative example 1 at 2300 Hz. In comparative example 1, edge irregularities are observed, but there is no wavefront disturbance.

[0044] FIG. 18(a) is a diagram showing the longitudinal wavefront of the example at 3200 Hz. FIG. 18(b) is a diagram showing the longitudinal wavefront of comparative example 1 at 3200 Hz. FIG. 19(a) is a diagram showing the longitudinal sound pressure distribution of the example at 3200 Hz. FIG. 19(b) is a diagram showing the longitudinal sound pressure distribution of comparative example 1 at 3200 Hz. In comparative example 1, wavefront disturbance occurs due to the antiphase mode in the longitudinal direction. On the other hand, no wavefront disturbance is observed in the example.

[0045] FIG. 20(a) is a diagram showing the longitudinal wavefront of the Example at 9200 Hz. FIG. 20(b) is a diagram showing the longitudinal wavefront of Comparative Example 1 at 9200 Hz. FIG. 21(a) is a diagram showing the longitudinal sound pressure distribution of the Example at 9200 Hz. FIG. 21(b) is a diagram showing the longitudinal sound pressure distribution of Comparative Example 1 at 9200 Hz. In Comparative Example 1, split resonance occurs in the longitudinal direction, causing significant disturbance to the wavefront. On the other hand, in the Example, there is no significant disturbance, and the wavefront remains close to spherical.

[0046] FIG. 22(a) is a diagram showing the longitudinal wavefront of the Example at 20,000 Hz. FIG. 22(b) is a diagram showing the longitudinal wavefront of Comparative Example 1 at 20,000 Hz. FIG. 23(a) is a diagram showing the longitudinal sound pressure distribution of the Example at 20,000 Hz. FIG. 23(b) is a diagram showing the longitudinal sound pressure distribution of Comparative Example 1 at 20,000 Hz. In Comparative Example 1, the wavefront is significantly disturbed due to split resonance. On the other hand, in the Example, the first reinforcing portion 3 and the second reinforcing portion 4 are used in combination, so a wavefront close to a spherical surface is maintained.

[0047] FIG. 24(a) is a diagram showing the wavefront in the longitudinal direction of the example at 2500 Hz. FIG. 24(b) is a diagram showing the wavefront in the longitudinal direction of the comparative example 2 at 2500 Hz. FIG. 25(a) is a diagram showing the sound pressure distribution in the longitudinal direction of the example at 2500 Hz. FIG. 25(b) is a diagram showing the sound pressure distribution in the longitudinal direction of the comparative example 2 at 2500 Hz. In the comparative example 2, wavefront disturbance occurs due to insufficient rigidity in the longitudinal direction. In the example, there is no significant disturbance, and the spherical wave is maintained.

[0048] FIG. 26(a) is a diagram showing the longitudinal wavefront of the Example at 3700 Hz. FIG. 26(b) is a diagram showing the longitudinal wavefront of Comparative Example 2 at 3700 Hz. FIG. 27(a) is a diagram showing the longitudinal sound pressure distribution of the Example at 3700 Hz. FIG. 27(b) is a diagram showing the longitudinal sound pressure distribution of Comparative Example 2 at 3700 Hz. In Comparative Example 2, the wavefront is slightly disturbed due to flapping of the edges in the longitudinal direction. On the other hand, no significant wavefront disturbance is observed in the Example.

[0049] As described above, this embodiment is provided with a first reinforcing portion 3 extending along the longitudinal direction and a second reinforcing portion 4 that is a mesh-like irregularity adjacent to the first reinforcing portion 3. This (1) suppresses flapping of the edge 5 provided on the diaphragm 1. In addition, (2) the first reinforcing portion 3 increases the overall rigidity, and the second reinforcing portion 4 efficiently disperses resonance peaks. According to this embodiment, peak dips in the diaphragm 1 are suppressed by (1) or (2).

[0050] Furthermore, the second reinforcing part 4 has a skeleton that spreads out radially from the center along the longitudinal direction, within a range that does not significantly affect the weight, and plays a role in complementing the first reinforcing part 3. This reduces split resonance in the high frequency range.

[0051] Here, the aspect ratio of the length in the longitudinal direction to the length in the lateral direction of diaphragm 1 is preferably 2:1 or more, and more preferably 3:1 or more. This is because, although a diaphragm with a large aspect ratio lacks rigidity in the longitudinal direction, the effects of first reinforcing portion 3 and second reinforcing portion 4 are more pronounced in such a diaphragm.

[0052] The mesh of the recesses and protrusions of the second reinforcing part 4 may be, for example, a lattice (a state in which multiple vertical and horizontal lines intersect). The mesh of the recesses and protrusions of the second reinforcing part 4 may be, for example, a regular shape in which multiple rectangular protrusions of the same shape are arranged. However, if the mesh of the recesses and protrusions of the second reinforcing part 4 has an irregular shape, such as the vein pattern shown in this embodiment, the effect of the second reinforcing part 4 on resonance dispersion is greater.

[0053] The above describes an embodiment of the present invention, but the forms to which the present invention can be applied are not limited to the above-described embodiment, and appropriate modifications can be made within the scope that does not deviate from the spirit of the present invention. [Industrial Applicability]

[0054] The present invention can be suitably employed in a diaphragm and a speaker unit including a diaphragm. [Explanation of symbols]

[0055] 1 diaphragm 2 aperture 3 First reinforcement section 4 Second reinforcement section 5. Edge 6 dust caps 7 frames 101 Speaker unit

Claims

1. A diaphragm having a predetermined shape in which, in a plan view, the length in one axial direction is different from the length in the other axial direction in two orthogonal axial directions, and both sides of the longitudinal direction, which is one axial direction, are formed by curves, a first reinforcing portion extending along the longitudinal direction; a second reinforcing portion that is a mesh-like irregularity provided adjacent to the first reinforcing portion in the short-side direction.

2. The diaphragm according to claim 1 , wherein the second reinforcing portion is formed to resemble an insect wing.

3. The diaphragm according to claim 2, characterized in that the second reinforcing portion is based on data obtained by measuring the shape of the actual wing veins of the insect, or on data of a Voronoi diagram that simulates the wing veins of the insect.

4. The second reinforcing portion is A plurality of polygonal convex portions; a plurality of polygonal recesses formed inside the protrusion by the protrusion, The diaphragm according to claim 1 , wherein one side of each of the adjacent convex portions is a part of both polygons.

5. The diaphragm according to claim 1 , wherein the second reinforcing portion extends radially from a center along the longitudinal direction.

6. The diaphragm according to claim 1 , wherein two second reinforcing portions are provided in the short-side direction, with the first reinforcing portion sandwiched therebetween.

7. The diaphragm according to claim 6 , wherein the mesh shapes of the two second reinforcing portions are different.

8. The diaphragm according to claim 6 , wherein the first reinforcing portion and the two second reinforcing portions are provided on opposite sides of the center in the longitudinal direction.

9. The diaphragm according to claim 8 , wherein the two second reinforcing portions sandwiching the center in the longitudinal direction are point-symmetric with respect to the center.

10. The diaphragm according to claim 1 , wherein the width of the first reinforcing portion gradually narrows from the center in the longitudinal direction along the longitudinal direction.

11. 2. The diaphragm according to claim 1, wherein an aspect ratio of the length in the longitudinal direction to the length in the lateral direction is 2:1 or more.

12. The diaphragm according to claim 1; a voice coil coupled to the opening of the diaphragm; a dust cap coupled to the voice coil; an edge connected to the outer periphery of the diaphragm; a frame to which the outer periphery of the edge is fixed; a magnetic circuit having a magnetic gap in which a coil of the voice coil is disposed and fixed to the frame; A speaker unit comprising:

Images