JP5266604B2 - Speaker diaphragm and speaker using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speaker diaphragm which suppresses a unique mode at an edge, in which a tone peculiar to a film-like member is hard to be caused, and by which suitable sound reproduction is made possible regarding the speaker diaphragm in which the film-like member using resin as a material is molded, and a dome part, a voice coil mounting part to be extended in the outer surroundings of the dome part and an edge are integrally constituted, and a speaker using the same. <P>SOLUTION: The inner circumferential edge and the outer circumferential edge of the edge are concentric circles with the center point O as the center, the radius r of a circular arc specifying the cross-section shape in the radius direction of the edge changes by monotonously increasing or monotonously decreasing between the minimum radius r1 and the maximum radius r2 according to a circumferential direction angle &theta; to be selected from either one of 180&deg;, 90&deg;, or 45&deg;. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a speaker diaphragm used for a speaker for reproducing sound and a speaker using the same, and typically, a speaker used for an electronic device such as a mobile phone, a notebook computer, an in-vehicle device, or a portable game machine. About.

  In a small speaker, for example, a film-like member made of a resin such as PEI (polyetherimide) is formed, and a dome portion and an edge portion extending around the outer periphery of the dome portion are integrated. A configured speaker diaphragm may be used. When this speaker is an electrodynamic speaker, a voice coil to which an audio signal current is supplied from the back side may be attached to a joint portion between the dome portion and the edge portion of the speaker diaphragm. The outer peripheral end side of the edge portion of the speaker diaphragm is fixed to a frame connected to a small and light magnetic circuit, and the voice coil is disposed in the magnetic gap of the magnetic circuit. The shape of the speaker diaphragm affects the quality and characteristics of sound reproduced by the small speaker and the overall shape and size of the small speaker.

  Conventionally, in a diaphragm in which a sub dome portion is continuously provided around the main dome portion, the sub dome portion includes a plurality of radial narrow grooves in order to flatten the relative sensitivity at 4 to 8 kHz. There is one in which the inner end of the groove reaches the boundary between the main dome portion and the sub dome portion (Patent Document 1).

  Further, conventionally, a plurality of roll portions having a roll-shaped cross section are arranged adjacent to each other with reference to a straight line connecting two points of the inner circumference or outer circumference, and the roll portion arranged first and the roll portion arranged last are adjacent. Conforms a closed loop shape that fits, and the adjacent boundary part of each roll part has a suspension connected by a continuous three-dimensional curved surface, and the inner circumference is a voice coil that fits into the magnetic gap of the magnetic circuit or this voice There is an electroacoustic transducer that is bonded to the outer periphery of a diaphragm connected to a coil, and the outer periphery is fixed to a casing that holds a magnetic circuit and a vibration system (Patent Document 2).

  Conventionally, a dome diaphragm is coupled to the upper end of the voice coil inserted into the magnetic gap of the magnetic circuit, and a roll edge having an inner circumference of a circle and an outer circumference is coupled to the outer circumference of the dome diaphragm. There is a speaker (Patent Document 3).

JP-A-8-140183 (FIGS. 1 to 3) JP 2004-7364 A (FIGS. 1 to 3) JP-A-3-212100 (FIGS. 1 and 2)

  However, the conventional speaker diaphragm and the speaker using the same may be insufficient in further improving the sound reproduction quality required for the speaker diaphragm for forming a film-like member made of resin. In other words, in a speaker diaphragm having an edge portion having a relatively large area with respect to the area of the dome portion of the speaker diaphragm, a plurality of radial grooves, or radial depressions are formed in a part of the roll shape. However, the eigenmode at the edge portion cannot be suppressed, and there is a problem that a tone color peculiar to the film-like member is likely to be generated.

  The present invention has been made in order to solve the above-described problems of the prior art. The purpose of the present invention is to form a film-like member made of a resin, and to form a dome portion and an outer periphery of the dome portion. With respect to a speaker diaphragm integrally configured with an extended voice coil mounting portion and an edge portion, and a speaker using the same, an eigenmode at the edge portion is suppressed, and the film-like member is unique. It is an object of the present invention to provide a speaker diaphragm that is less likely to produce timbre and is capable of preferable sound reproduction.

  The speaker diaphragm of the present invention is formed by forming a film-like member and extending to the outer periphery of the voice coil mounting portion, the dome portion formed at the center, the voice coil mounting portion extending around the outer periphery of the dome portion. And an edge portion having an arcuate radial cross section, and an inner peripheral end and an outer peripheral end of the edge portion are concentric circles with a center point O as a center, The radius r of the arc that defines the radial cross-sectional shape of the portion is between the minimum radius r1 and the maximum radius r2 according to a circumferential angle θ selected from either 180 °, 90 °, or 45 °. It changes with monotonic increase or monotonic decrease.

  Preferably, in the speaker diaphragm of the present invention, the maximum height h1 of the edge portion corresponding to the minimum radius r1 of the arc that defines the radial cross-sectional shape of the edge portion is the minimum height h2 of the edge portion corresponding to the maximum radius r2. 2 times or less.

  Preferably, in the speaker diaphragm of the present invention, the edge portion includes a plurality of grooves formed radially from the inner peripheral end to the outer peripheral end in a radial direction, and a circumferential angle φ defining an interval between the plurality of groove portions is set. The depth d of the plurality of groove portions is set to a value smaller than the circumferential angle θ, and is constant at the top of the arc that defines the radial cross-sectional shape.

  Preferably, the speaker diaphragm of the present invention further includes a voice coil attached to the voice coil attachment portion.

  The speaker of the present invention includes the speaker diaphragm of the present invention.

  The operation of the present invention will be described below.

  The speaker diaphragm of the present invention is formed of a film-like member made of a resin such as PEI (polyetherimide), and is typically small and thin used in a mobile phone or a portable game machine. A speaker diaphragm suitable for a speaker, a dome portion at the center, a voice coil mounting portion extending around the outer periphery of the dome portion, and an edge portion extending around the outer periphery of the voice coil mounting portion Are integrally formed. The dome portion has a convex shape on the front side, and constitutes a radially inner side when viewed from a voice coil attached from the back side. The dome portion is a portion in which the driving force from the voice coil is well transmitted in the surface area of the speaker diaphragm, and thus plays a major role as a diaphragm that emits sound waves.

  On the other hand, the edge portion constitutes an outer side in the radial direction from the voice coil, a convex roll is formed on the front side, and a flat fixing portion extending from the outer peripheral end is fixed to the frame. Further, in a speaker diaphragm having an edge portion having a relatively large area with respect to the area of the dome portion of the speaker diaphragm, the edge portion supports the dome portion so as to vibrate and emits sound waves. Also works. The edge portion is a concentric circle with the inner peripheral end and the outer peripheral end of the edge portion centering on the center point O. Therefore, the speaker diaphragm of the present invention is a speaker diaphragm having a circular outer shape and a dome diaphragm having a circular outer shape and a circular voice coil.

  In the edge portion, the radius r of the circular arc defining the radial cross-sectional shape gradually changes from the minimum radius r1 to the maximum radius r2 according to the circumferential angle θ defined by the center point O. Preferably, the radius r of the arc that defines the radial cross-sectional shape of the edge portion is set to a minimum radius r1 and a maximum radius r2 according to a circumferential angle θ selected from one of 180 °, 90 °, and 45 °. And monotonically increasing or decreasing. Since the radius r of the arc that defines the radial cross-sectional shape of the edge portion gradually changes from the minimum radius r1 to the maximum radius r2, as a result, the dimension h of the height of the roll of the edge portion is determined in the circumferential direction. As the angle θ changes, a roll surface that gradually changes from the maximum height h1 to the minimum height h2 is formed. In addition, Preferably, the maximum height h1 of the height of the roll of an edge part is 2 times or less of minimum height h2.

  For example, when the radius r of the arc that defines the size of the roll of the edge portion is 90 ° in the circumferential direction, the radius increases monotonically from the minimum radius r1 to the maximum radius r2 during a quarter of the circumference. , Monotonically decreasing from the maximum radius r2 to the minimum radius r1 during 1/4 of the next circumference, and further monotonously increasing at 1/4 of the next circumference, and monotonically decreasing at 1/4 of the next circumference To do. Therefore, since the roll of the edge part repeats undulations in the circumferential direction and becomes continuous, the rigidity of the edge part is improved and the eigenmode at the edge part is suppressed. The speaker diaphragm further provided with the voice coil attached to the voice coil attachment portion is less likely to produce a timbre unique to the film-like member, and a speaker capable of preferable sound reproduction can be realized.

  Preferably, the rigidity of the edge portion can be further improved by providing a plurality of groove portions radially formed in the radial direction from the inner peripheral end to the outer peripheral end. In that case, by setting the circumferential angle φ that defines the interval between the plurality of grooves to a value smaller than the circumferential angle θ, the radius r of the arc that defines the radial cross-sectional shape of the roll of the edge portion is set. Since the plurality of groove portions are radially arranged where the radius gradually changes between the minimum radius r1 and the maximum radius r2, the rigidity of the roll of the edge portion can be further increased and the natural mode can be suppressed. . By making the depths d of the plurality of groove portions constant at the tops of the arcs that define the radial cross-sectional shape, the flexibility and rigidity required for the edge portions can be realized in a balanced manner.

  In addition, the convex shape on the front surface side forming the dome portion may have a concave portion in the center portion thereof in order to suppress the overall height as a speaker. In the speaker using the speaker diaphragm of the present invention, the rigidity of the edge portion is enhanced by its shape, so that even when an input signal having a wide reproduction frequency range and a large amplitude is applied to the voice coil, Defects such as abnormal noise are less likely to occur, and preferable audio reproduction is possible.

  The speaker using the speaker diaphragm of the present invention can realize a speaker that is unlikely to produce a timbre unique to the film-like member and can perform preferable audio reproduction.

  In the speaker diaphragm of the present invention, a film-like member made of resin is formed, and the dome part, the voice coil attachment part extending around the outer periphery of the dome part, and the edge part are integrated. With respect to the configured speaker diaphragm and a speaker using the same, it is possible to provide a speaker diaphragm capable of suppressing preferable eigenmodes at the edge portion, hardly generating a timbre peculiar to the film-like member, and capable of preferable sound reproduction. For the purpose, the inner peripheral edge and the outer peripheral edge of the edge portion are concentric circles centered on the center point O, and the radius r of the arc that defines the radial sectional shape of the edge portion is 180 °, 90 °, or 45 This is realized by changing monotonically increasing or monotonically decreasing between the minimum radius r1 and the maximum radius r2 in accordance with the circumferential angle θ selected from any of °.

  Hereinafter, although the speaker diaphragm by preferable embodiment of this invention and the speaker using the same are demonstrated, this invention is not limited to these embodiment.

  FIG. 1 is a diagram illustrating a speaker diaphragm 10 according to a preferred embodiment of the present invention. 1A is a front view of the speaker diaphragm 10, FIG. 1B is a side sectional view taken along the line AA ′, and FIG. 1C is a side sectional view taken along the line BB ′. It is sectional drawing. The speaker diaphragm 10 of the present embodiment is a speaker diaphragm used for a small and thin electrodynamic speaker (not shown) having a diameter of 20 mm, and a film-like member made of PEI (polyetherimide) resin is formed. Obtained.

  The speaker (not shown) according to the present embodiment includes a pole that is composed of a pole, a magnet, and a yoke and has a magnetic gap, a frame that is attached to the magnetic circuit and supports the speaker diaphragm 10 so as to vibrate, and a speaker. A voice coil attached to the back side of the diaphragm 10 and disposed in the magnetic gap. The frame is connected to a terminal for supplying an audio signal current to the voice coil. The voice coil is bonded and fixed to the back side of the speaker diaphragm 10 with an adhesive. In the speaker (not shown) of this embodiment, the side where the speaker diaphragm 10 is exposed is the front side, and the side where the magnetic circuit is exposed is the back side.

  In a speaker (not shown), a voice coil is disposed in a magnetic gap where a strong DC magnetic field is generated, and when an audio signal current is supplied to the voice coil, a driving force is generated in the front-rear direction of the speaker diaphragm 10, A speaker vibration system including the voice coil and the speaker diaphragm 10 vibrates in the front-rear direction. That is, the speaker vibration system is supported so as to be vibrated by the edge 13 of the speaker diaphragm 10 to be described later. As a result, a pressure change occurs in the air existing before and after the speaker diaphragm 10, and the sound signal current is converted into sound waves ( Voice).

  The speaker diaphragm 10 is a dome / edge integrated diaphragm formed through a press molding process of a film-like member having a thickness of 30 μm made of PEI (polyetherimide) resin. That is, the speaker diaphragm 10 has a substantially dome-shaped dome portion 11 that is convex on the front side formed at the center, a voice coil attachment portion 12 that extends around the outer periphery of the dome portion 11, and a voice coil attachment. This is a speaker diaphragm in which an edge portion 13 extending around the outer periphery of the portion 12 and a fixing portion 14 extending around the outer periphery of the edge portion 13 and fixed to the frame are integrally formed. The fixing portion 14 is a flat portion fixed to the frame, and the outer diameter thereof is about φ18 mm. The edge portion 13 is formed with 24 groove portions 15 to be described later.

  The dome portion 11 constitutes the radial inner side of a circular region defined by the voice coil 5 attached from the back side in the speaker diaphragm 10, and its schematic shape is a convex portion on the front side. The radius of the circular arc that defines the radial cross-sectional shape of the dome portion 11 is about 8.6 mm. Moreover, the outer diameter diameter of the dome part 11 centering on the center point O is about φ8.1 mm. A flat voice coil attachment portion 12 extends from the outer edge portion of the dome portion 11.

  The voice coil attachment portion 12 is a narrow flat portion to which a voice coil (not shown) is attached on the outer peripheral end side of the dome portion 11 and has a radial width of about 0.8 mm. An edge portion 13 extends from the outer edge portion of the voice coil attachment portion 12 to the outer periphery thereof.

  The edge portion 13 constitutes the outer side in the radial direction of the circular region defined by the voice coil, and functions as a diaphragm that radiates sound waves by forming a convex roll on the front side while vibrating the dome portion 11. Support as possible. The inner peripheral end and the outer peripheral end of the edge portion 13 are concentric circles centered on the center point O, the inner diameter is about φ8.9 mm, and the outer diameter is about φ17.2 mm. As shown in FIG. 1, the roll convex on the front side of the edge portion 13 is a continuous roll with undulations in the circumferential direction. In the cross-sectional side view of the −B ′ cross section, the cross-sectional shape of the edge portion 13 is different.

  In the edge portion 13, the radius r of the arc that defines the radial cross-sectional shape changes according to the circumferential angle θ. The circumferential angle θ is, for example, an angle defined by a straight line connecting the points A-O-B. In the present embodiment, the radius r of the arc that defines the radial cross-sectional shape of the edge portion 13 is: When the circumferential angle θ is in the range of 90 °, it changes monotonously increasing or monotonically decreasing between the minimum radius r1 (= 2.6 mm) and the maximum radius r2 (= 4.6 mm). Therefore, the arc defining the radial cross-sectional shape of the edge portion 13 gradually increases monotonously in the radius r from the point A to the point B in the circumferential direction, and from the point B to the point A in the circumferential direction at the next 90 °. The radius r gradually decreases monotonously as it goes to ', and further gradually increases monotonously as it moves from point A' to point B 'in the circumferential direction at the next 90 °, and further increases at the next 90 °. The radius r gradually monotonously decreases from the point B ′ toward the point A in the direction.

Further, the height h of the convex roll on the front surface side of the edge portion 13 is such that the circumferential angle θ is 90 ° as the radius r of the arc defining the radial cross-section changes. The maximum height h1 (= about 1.0 mm) and the minimum height r2 (= about 0.5 mm) change monotonously increasing or monotonically decreasing. The height of the top of the roll surface of the edge portion 13 is the maximum height h1 in the direction of the points A and A ′, and the points B and B ′ shifted by 90 ° in the circumferential direction.
Is the minimum height h2. As a result, the roll height dimension h of the edge portion 13 gradually changes from the maximum height h1 to the minimum height h2 as the circumferential angle θ changes.

  In the edge portion 13, 24 groove portions 15 are radially formed from the inner peripheral end to the outer peripheral end in the radial direction. Each of the 24 groove portions 15 has a width of about 0.2 mm, and the interval is defined for each circumferential angle φ (= 15 °). Each groove portion 15 is a concave portion on the front surface side by a substantially constant depth from the roll surface of the edge portion 13, and is a convex portion when the speaker diaphragm 10 is viewed from the rear surface side. In the case of the speaker diaphragm 10 of the present embodiment, the depth d of the groove 15 is constant and about 0.5 mm at the top of the circular arc that defines the radial cross-sectional shape.

  Since the circumferential direction angle φ (= 15 °) that defines the interval between the plurality of groove portions 15 is smaller than the circumferential direction angle θ (= 90 °), in the present embodiment, the five groove portions 15 are circumferentially It is equally arranged in the middle of 1/4. Accordingly, the plurality of groove portions 15 act as a plurality of ribs that increase the rigidity of the roll in a circumferential section where the radius r of the arc forming the edge portion 13 gradually increases or decreases monotonously. The plurality of groove portions 15 can further increase the rigidity of the roll of the edge portion 13 and can suppress the natural mode. By making the depths d of the plurality of groove portions constant at the tops of the arcs that define the radial cross-sectional shape, the flexibility and rigidity required for the edge portions can be realized in a balanced manner.

  FIG. 2 is a diagram illustrating a speaker diaphragm 20 of a comparative example. 2A is a front view of the speaker diaphragm 20, FIG. 2B is a side sectional view taken along the line AA ′, and FIG. 2C is a side sectional view taken along the line BB ′. It is sectional drawing. The speaker diaphragm 20 of the comparative example is a speaker diaphragm formed so that the roll shape of the edge portion 23 is substantially the same except that the roll shape of the edge portion 13 of the speaker diaphragm 10 of the present embodiment is different. A film-like member made of PEI (polyetherimide) resin is formed. Therefore, descriptions of the dome portion 21, the voice coil mounting portion 22, the fixing portion 24, and the plurality of groove portions 25 of the speaker diaphragm 20 are common and will be omitted.

  As shown in FIG. 2, in the speaker diaphragm 20 of the comparative example, the edge portion 23 is a roll convex on the front side, and an arc radius r (= 2.6 mm) defining the radial cross-sectional shape. ) And the height h1 (= about 1.0 mm) of the top of the roll surface have a uniform roll shape that does not change in the circumferential direction. That is, unlike the present embodiment, the undulations are not repeated in the circumferential direction, and the rigidity of the edge portion 23 of the speaker diaphragm 20 of the comparative example is only increased by the plurality of groove portions 25. . As a result, since the suppression of the eigenmode at the edge portion 23 is not sufficient, the speaker of the comparative example (not shown) further provided with a voice coil attached to the voice coil attachment portion 22 of the speaker diaphragm 20 is provided on the film-like member. There is a problem that a unique timbre tends to occur.

  FIG. 3 is a graph showing the sound pressure frequency characteristics (at the time of 1 W input / converted on the 1 m axis) of the speaker (not shown) including the speaker diaphragm 10 of this embodiment and the harmonic distortion factor. The horizontal axis represents the frequency of the audio signal (Frequency: Hz), and the vertical axis represents the sound pressure level (SPL: dB) in the case of the sound pressure frequency characteristic, and the distortion rate (%) in the case of the harmonic distortion factor. In the harmonic distortion graph, the 10th to 20th harmonics with respect to the fundamental frequency of the input signal are plotted with dotted lines.

  In the case of a speaker including the speaker diaphragm 10 of the present embodiment, the lowest resonance frequency f0 is about 800 Hz, and a wide reproduction frequency range from the lowest resonance frequency f0 to about 40 kHz is secured. Moreover, since the rigidity of the dome part 11 and the edge part 13 is improved in a well-balanced manner, a remarkable peak or dip is reduced, and a relatively flat characteristic is obtained. In addition, at the lowest resonance frequency f0 Hz or higher, the harmonic distortion is extremely low, and is substantially below 0.1%. In addition, although it is formed of a film-like member made of PEI (polyetherimide) resin, there are few timbres or incidental sounds peculiar to resin-made diaphragms such as PEI resin. Good sound reproduction is possible from the speaker 1.

  FIG. 4 is a graph showing the sound pressure frequency characteristics of a comparative example (not shown) using the speaker diaphragm 20 of the comparative example (at the time of 1 W input / converted on the 1 m axis) and the harmonic distortion. In the case of the speaker of the comparative example, the sound pressure frequency characteristic shows the frequency characteristic having the same tendency as in the example, but the rigidity of the edge portion 23 of the speaker diaphragm 20 is insufficient, so that the lowest resonance frequency f0 Hz. In the above, the harmonic distortion becomes large, and the input sine wave shows a distortion rate exceeding 0.1% at a frequency in the vicinity of about 1 kHz. In addition, since the edge portion 23 is insufficiently rigid, when a sound is actually reproduced, a tone color or incidental sound peculiar to the PEI resin appears.

  Further, the speaker diaphragm 10 of the present invention is not limited to the above-described embodiment, and the speaker diaphragm 10 may be another large-sized speaker having a large caliber and having another damper. However, the present invention is applicable to any speaker diaphragm in which a film-like member is formed and the dome portion 11 and the edge portion 13 extending around the outer periphery of the dome portion 11 are integrally formed.

  Even when the circumferential angle θ described above is other than 90 °, if the inner peripheral end and the outer peripheral end of the edge portion 13 of the speaker diaphragm 10 are concentric circles centered on the center point O, the edge portion The radius r of the arc that defines the 13 radial cross-sectional shapes only needs to change monotonously increasing or decreasing between the minimum radius r1 and the maximum radius r2. For example, when the circumferential angle θ is 180 °, the radius r of the arc that defines the radial sectional shape of the edge portion 13 increases monotonously from the minimum radius r1 to the maximum radius r2 during ½ of the circumference. , Monotonously decreases from the maximum radius r2 to the minimum radius r1 during ½ of the next circumference. When the circumferential angle θ is 45 °, the radius r of the arc that defines the radial cross-sectional shape of the edge portion 13 increases monotonously from the minimum radius r1 to the maximum radius r2 during 1/8 of the circumference. The monotonous decrease from the maximum radius r2 to the minimum radius r1 during 1/8 of the circumference of the circle is repeated four times. Thus, what is necessary is just to form the roll surface of the edge part 13 which the speaker diaphragm 10 has undulations.

  In these cases, preferably, the speaker diaphragm 10 is configured such that the maximum height h1 of the edge portion corresponding to the minimum radius r1 of the circular arc that defines the radial sectional shape of the edge portion 13 is the edge corresponding to the maximum radius r2. What is necessary is just to make it 2 times or less of the minimum height h2. Within this range, the roll surface of the edge portion 13 is gently undulated, so that defects such as abnormal noise are unlikely to occur, and preferable audio reproduction is possible.

  Moreover, the resin material which comprises the speaker diaphragm 10 of this invention is not limited to the film-like member of PEI of the said Example. Examples of the material forming the speaker diaphragm 10 include other PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PC (polycarbonate), PI (polyimide), PAR (polyarylate), PPS (polyphenylene sulfide), and the like. A lightweight resin material film or sheet formed by hot pressing may be used, or an elastomer sheet may be formed by press molding.

  Further, the speaker diaphragm and the speaker of the present invention are not limited to the above embodiments. For example, the magnetic circuit is not limited to an inner magnet type magnetic circuit, and may be an outer magnet type magnetic circuit or a repulsive type magnetic circuit.

  The speaker diaphragm of the present invention is not limited to a speaker used in a portable electronic device such as a mobile phone or a portable game device, but is used in a speaker for home stereo playback or multi-channel surround playback, and an in-vehicle audio device. It can also be applied to speakers that are used.

It is a figure explaining the speaker diaphragm 10 by preferable embodiment of this invention. Example 1 It is a figure explaining the speaker diaphragm 20 of a comparative example. Example 1 4 is a graph showing sound pressure frequency characteristics of a speaker according to a preferred embodiment of the present invention. Example 1 It is a graph showing the sound pressure frequency characteristic of the speaker using the speaker diaphragm of the comparative example. (Comparative example)

Explanation of symbols

10, 20 Speaker diaphragm 11, 21 Dome part 12, 22 Voice coil attachment part 13, 23 Edge part 14, 24 Fixed part 15, 25 Groove part

Claims (5)

A film-like member is formed, and a dome portion formed at the center, a voice coil attachment portion extending around the outer periphery of the dome portion, and an arc-like shape extending around the outer periphery of the voice coil attachment portion A speaker diaphragm integrally configured with an edge portion having a radial cross section,
The inner peripheral edge and the outer peripheral edge of the edge portion are concentric circles centered on the center point O, and the radius r of the arc that defines the radial cross-sectional shape of the edge portion is 180 °, 90 °, or 45 °. Varies in a monotonically increasing or monotonically decreasing manner between the minimum radius r1 and the maximum radius r2, according to a circumferential angle θ selected from:
Speaker diaphragm. The maximum height h1 of the edge portion corresponding to the minimum radius r1 of the arc defining the radial cross-sectional shape of the edge portion is not more than twice the minimum height h2 of the edge portion corresponding to the maximum radius r2.
The speaker diaphragm according to claim 1. The edge portion includes a plurality of grooves formed radially from the inner peripheral end to the outer peripheral end in a radial direction, and a circumferential angle φ that defines an interval between the plurality of the groove portions is the circumferential angle θ. The depth d of the plurality of grooves is constant at the top of the arc defining the radial cross-sectional shape,
The speaker diaphragm according to claim 1 or 2. A voice coil attached to the voice coil attachment portion;
The speaker diaphragm according to any one of claims 1 to 3.   A speaker comprising the speaker diaphragm according to claim 4.