KR20100042178A - Diaphrahm for sound converter - Google Patents

Abstract

PURPOSE: A diaphragm for a sound converter is provided to induce sound pressure in a baseband by maximizing the volume of a magnet mounted in the sound converter. CONSTITUTION: A vibration plate for converting sound is composed of a first vibration plate(62) and a second vibration plate(64). The first vibration plate is composed of a central part which is a plane and a side dome which is formed in the circumference of the central part. A second vibration plate is formed in the central part of the first vibration plate. An opening is formed in the center of the central part of the first vibration plate. A second vibration plate is formed on a central mounting unit around the opening. The central mounting unit is connected to the side dome. A step height guiding the second vibration plate is formed on the inner side of the dome of the first vibration plate.

Description

Diaphragm for sound transducer {DIAPHRAHM FOR SOUND CONVERTER}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm for an acoustic transducer, and to a diaphragm and an acoustic transducer for increasing the effective area of the diaphragm of the acoustic transducer and lowering the rigidity of the diaphragm.

In general, a speaker converts electrical energy into mechanical energy by a voice coil existing between pores by Fleming's left-hand law that a conductor in which current flows in a magnetic field receives a force. That is, when a current signal containing several frequencies is applied to the voice coil, the voice coil generates mechanical energy according to the strength of the current and the magnitude of the frequency, and generates vibration on the diaphragm attached to the voice coil, thereby ultimately recognizing the human ear. It can generate a sound pressure of a predetermined magnitude.

The magnetic circuits of these speakers are designed so that the magnetic flux can be bridged at right angles to the voice coils present in the air gap by using a magnet (permanent magnet) and a top plate (or upper plate) in the yoke made of ferrous metal, respectively. The work is bonded to the diaphragm to generate the up and down excitation force by the input signal to vibrate the diaphragm attached to the frame to generate sound pressure. The diaphragm has various shapes of waves in order to remove the buckling phenomenon and excellent response during the up and down oscillation, and the shape of the diaphragm acts as a design variable having the greatest influence on the frequency characteristics.

1 is a cross-sectional view of a microspeaker according to the prior art.

As shown in FIG. 1, the microspeaker transmits the magnetic flux to or from the frame 1, the yoke 2 inserted and mounted inside the frame 1, and the yoke 2. Inner ring top plate (5) receiving magnetic flux from inner ring magnet (3) and outer ring magnet (4) and inner ring magnet (3) or outer ring magnet (4) to transmit magnetic force at right angles to voice coil (7) and A voice coil 7 and a voice coil in which a portion is inserted into the space between the outer ring top plate 6, the inner ring magnet 3 and the inner ring top plate 5, and the outer ring magnet 4 and the outer ring top plate 6 7) is attached to the inner side of the diaphragm 8 to generate a vibration in accordance with the vertical movement of the voice coil (7), the ventilation hole (9) provided in the frame 1 of the lower side of the diaphragm (8), the sound emission hole A protector 10 is formed to protect the diaphragm 8 and a leader line (not shown) of the voice coil 7 is formed in the frame 1. Through the side through a groove (not shown) formed in or frame (1) is drawn out are respectively soldered to the connection terminals 12 along the outer side of the frame (1). The connection terminal 12 allows a pair of lead wires (not shown) and lead wires (input lines and output lines) to be connected to each other from the outside.

The diaphragm 8 consists of a dome-shaped center dome 8a at the center, and a side dome 8b formed around the center dome 8a.

In the case of a general microspeaker, the acoustic characteristics are greatly affected by the size of the back volume of a device (for example, a mobile communication terminal) on which the microspeaker is mounted. According to the Helmholtz resonance equation, the back volume has a great influence on the equivalent stiffness of air. The smaller the back volume, the higher the equivalent stiffness, which lowers the sound pressure in the low range and increases the first resonance frequency.

In a magnetic circuit as in the prior art, within the limited frame size, it is difficult to increase the size of the entire magnets 3 and 4, making it difficult to increase the electromagnetic force. In addition, in the diaphragm according to the prior art, the side dome is relatively wide, and the effective area of the diaphragm is reduced, so that the sound pressure is lowered, and the diaphragm is formed from a single film having a relatively high rigidity, thereby deteriorating low frequency vibration characteristics. Moreover, when the back volume is small, this low frequency vibration characteristic is further deteriorated.

An object of the present invention is to provide a sound conversion device to maximize the volume of the magnet mounted to the sound conversion device.

In addition, an object of the present invention is to provide an acoustic conversion device having a diaphragm for optimizing the width of the side dome and increasing the effective area of the diaphragm.

Moreover, an object of this invention is to provide the acoustic conversion apparatus which makes it easy to laminate | stack a diaphragm which consists of multiple layers.

The diaphragm for an acoustic transducer according to the present invention comprises a first vibration plate made of a planar center part and a side dome formed around the center part, and a second vibration plate formed at the center part of the first vibration plate.

In addition, the central portion of the first vibration plate is composed of an opening in the center and a central seat end where the second vibration plate is mounted around the opening, and the central seat end is connected to the side dome.

In addition, a step for guiding the second vibration plate is formed inside the side dome of the first vibration plate.

In addition, it is preferable that the side dome of the first vibration plate and the second vibration plate are spaced apart from each other by a predetermined interval.

In addition, the first vibration plate is a first sub-vibration plate containing a thermoplastic polyurethane elastomer (TPU), polyester (PET) material , polyetherimide (PEI) material, polyether ether ketone It is made of a laminate of a second sub-vibration plate including at least one of a (PEEK) material, a polyarylate material.

In addition, it is preferable that the first sub diaphragm and the second sub diaphragm are sequentially positioned and laminated.

Further, the second vibration plate is composed of first and second metal layers and an elastic layer laminated between the first and second metal layers.

In addition, the first and second metal layers are preferably aluminum layers.

In addition, the elastic layer is preferably a styrofoam (PS material) layer.

In addition, it is preferable that the width of the side dome corresponds to 10 to 20% of the radius of the diaphragm or 20 to 30% of the radius of the diaphragm short axis.

In addition, the thickness of the second vibration plate is preferably 0.25 to 0.35 mm.

In addition, the acoustic transducer according to the present invention includes a diaphragm according to any one of claims 1 to 12, a coil portion mounted around a bottom surface of a central portion of the diaphragm, and a magnetic circuit for intersecting magnetic flux at right angles to at least a portion of the coil portion. And a frame having a first accommodating portion accommodating a magnetic circuit on the lower side, a second accommodating portion accommodating the diaphragm on the upper side, and a protector protecting the diaphragm on the upper side of the frame.

In addition, the coil unit attached to the rear surface of the diaphragm is preferably mounted so as to overlap a predetermined width or more on the second vibrating plate with the first vibrating plate interposed therebetween.

Moreover, it is preferable that a certain degree is 50% or more.

In addition, the protector is preferably provided with a sound emitting hole having a size equal to or wider than the center portion of the diaphragm or the second vibrating plate.

The sound conversion device of the present invention is thinner than the central portion, which is a flat plate, and the thickness of the central portion.

A diaphragm having a thickness and having a side dome formed around the center portion, a diaphragm assembly composed of a coil portion mounted around the bottom of the center portion, a magnetic circuit allowing magnetic flux to be bridged at right angles to at least a portion of the coil portion, and a magnetic circuit below. And a frame having a first accommodating part for accommodating the first accommodating part, a second accommodating part accommodating the diaphragm assembly so that the coil part is disposed between the spaced spaces on the upper side, and a protector for protecting the diaphragm assembly on the upper side of the frame.

The present invention has the effect of maximizing the volume of the magnet mounted on the sound conversion device, thereby inducing sound pressure improvement in the low frequency band.

In addition, the present invention has the effect of improving the low-frequency vibration characteristics, widening the effective area of the diaphragm to improve the sound pressure.

In addition, the present invention is to facilitate the lamination of the diaphragm consisting of a plurality of layers, there is an effect to make the production easy and accurate.

In the following, the invention is explained in detail based on the embodiments of the invention and the accompanying drawings.

2 is a cross-sectional view of the applied acoustic transducer of the diaphragm according to the present invention, FIG. 3 is a perspective view of the yoke assembly of FIG. 2, and FIGS. 4A and 4B are a perspective view and a plan view of the frame of FIG. 2.

The acoustic transducer of FIG. 2 includes a frame 20, yoke assemblies 30, 40, and 42 fixedly mounted to the lower side of the frame 20 to form a separation space A to form a magnetic circuit, and a separation space ( A) The coil part 50 into which at least one part is inserted, the coil part 50 is mounted in the lower end (or bottom surface), the diaphragm 60 mounted in the frame 20, and the sound emission hole 72 are And a protector 70 formed to protect the diaphragm 60, and a ventilation hole 80 provided in the frame 20 below the diaphragm 60, and a leader line (not shown) of the coil part 50 is provided. It is provided with a connection terminal 90 penetrating through the side of the frame 20 or through the groove (not shown) formed in the frame 20 to be connected to the outside along the outer side of the frame 20, respectively. The connection terminal 90 allows a pair of lead wires (not shown) and lead wires (input lines and output lines) to be connected to each other from the outside. Here, the coil unit 50 and the diaphragm 60 may be collectively referred to as a diaphragm assembly.

The diaphragm 60 has a laminated structure of the first vibrating plate 62 and the second vibrating plate 64 mounted on the upper surface of the first vibrating plate 62. The central portion of the first vibrating plate 62 has a planar shape, a side dome is formed around the central portion, and a seating portion 66 fixed to the frame 20 is formed at an edge of the side dome. The second vibration plate 64 is located in the center of the first vibration plate 62 in a planar shape.

The coil unit 50 is mounted on the rear surface of the diaphragm 60, and is mounted corresponding to the center portion of the first vibration plate 62 or the edge of the second vibration plate 64 or the mounting position of the second vibration plate 64.

The yoke assembly is spaced apart from the yoke 30 including the base 30a, the side plate 30b forming a wall at the edge of the base 30a, and the side plate 30b on the upper surface of the base 30a at predetermined intervals. The magnet 40 is mounted to form the separation space A, and the top plate 42 is mounted on the upper surface of the magnet 40. The magnetic flux passes through the space A between the top plate 42 and the site plate 30b, and at least a portion of the coil part 50 is positioned at right angles to the magnetic flux. The yoke 30, the magnet 40, and the top plate 42 of the yoke assembly may be oval type, circular, rectangular, or track type, as shown, and the diaphragm 60 and the coil part according to the shape. The form of 50 may be modified.

Magnet 40 is formed of a one-magnet type, the magnetic field efficiency is high. In particular, since the side dome of the diaphragm 60 is to occupy a smaller area than the central portion of the plane, since the magnet 40 may have a somewhat smaller area than the central portion occupying a large area, the magnet 40 of a larger area Can be mounted. Therefore, since maximizing the area (or volume) of the magnet 40 is the maximization of the magnetic circuit, the sound pressure of the acoustic transducer can be improved in the entire frequency band.

The yoke 30 has a fixing protrusion 32 for fixing to the frame 20 on the upper outer surface of the side plate 30b in parallel to the major axis direction and / or the minor axis direction. The fixing protrusion 32 may be changed in its mounting position as necessary.

In addition, the yoke 30 includes a groove 34 in a space where the lead line travels so that the lead line of the coil part 50 and the site plate 30b do not interfere with the side plate 30b. Through the provision of the grooves 34, even when the coil unit 50 vibrates and the lead wire vibrates under the influence of the vibration when the acoustic transducer is driven, the lead wire and the yoke 30 (particularly, the side plate 30b). )) Can be prevented. These grooves 34 are formed at corners where the long and short axes meet. The position of this groove 34 is once again disclosed in the detailed description of the coil section 50 below.

Next, the relationship between the radius Yr of the magnetic circuit and the radius Fr of the frame 20 for maximum generation of electromagnetic force will be described. In the case of a circular shape, the radius Yr of the magnetic circuit is designed to be about 75% to 85% of the radius Fr of the frame 20. If the radius Yr of the magnetic circuit is smaller than this design accuracy, the electromagnetic force is lowered, so that the sound pressure improvement at the low volume cannot be obtained. If the diameter is larger than this, the ventilation hole 80 is reduced in size, resulting in a sound pressure drop or a frame ( 20) Thinness can affect product reliability. In the case of the Oval or square type, the uniaxial magnetic circuit radius is designed to be 75% ~ 80% of the size of the uniaxial frame.

As shown in FIGS. 4A and 4B, the frame 20 includes a first receptacle 22 for receiving and mounting a yoke assembly (especially yoke 30) and a diaphragm assembly (especially diaphragm 60). And a second accommodating portion 25 accommodating and mounting the protector 70, a lead-out groove 27 allowing the lead wire of the coil part 50 to travel to the outside, and a lead wire of the coil part 50. A groove 28 is provided to advance through the groove 34 to the groove 27. However, since the frame 20 is an insulating material, the lead wire of the coil part 50 may contact the side and bottom of the lead groove 27 or 28 in the lead groove 27 or 28. The drawing groove 27 corresponds to a space formed stepped in the receiving groove 29a, the receiving groove 29a is formed in a pair corresponding to the short axis direction, the receiving groove 29b is a pair corresponding to the long axis direction Is formed. In these receiving grooves 29a and 29b, guide protrusions 68a and 68b (see Fig. 8) of the diaphragm 60 described below are accommodated.

The first accommodating part 22 and the second accommodating part 24 are divided by the partition wall 23. The partition wall 23 accommodates the fixing protrusion 32 of the yoke 30 to accommodate the yoke 30. A plurality of fixing grooves 24 for fixing are formed. In addition, the partition 23 is provided with a ventilation hole 80 through which the first accommodating part 22 and the second accommodating part 25 pass. In addition, the partition wall 23 is formed with a groove 28, the groove 28 is formed at a position corresponding to the groove 34 of the yoke 30 described above, the long and short axis of the frame 20 It is formed near the contact corner.

Since the inner surface of the first accommodating portion 22 is in contact with the outer surface of the side plate 30b of the yoke 30 and the fixing protrusion 32 is inserted into the fixing groove 24, the yoke assembly is framed. 20 is fixedly mounted.

The second accommodating portion 25 has a diaphragm seating portion 26 to allow the seating portion 66 of the diaphragm 60 to be fixedly mounted. After the mounting portion 66 of the diaphragm 60 is fixedly mounted on the diaphragm seating portion 26, the protector 70 is fixedly mounted thereon.

5A and 5B are views illustrating a manufacturing process of the diaphragm.

FIG. 5A illustrates a process of forming the first diaphragm 62. The first vibrating plate 62 includes a first sub diaphragm 62a including a thermoplastic polyurethane elastic material (TPU) material for minimizing the rigidity of the diaphragm. The second sub diaphragm 62b including at least one of a material such as polyetherimide (PEI), polyester (PET) or polyester ether ketone (PEEK), polyarylate material, etc. Molded into a laminated film. In particular, since the TPU material is soft and can be attached to the mold during the molding process, the TPU material is always laminated on the upper surface of the second sub diaphragm 62b.

Through such molding, the first vibrating plate 62 is formed with a central portion C, a side dome S, and a seating portion 66. As shown in Figure 5a, instead of reducing the width of the side dome (S) instead of using a soft diaphragm material to improve the low-frequency vibration characteristics and the diaphragm of the central portion (C) having a wide plate-like structure, the diaphragm 60 The effective area is widened to improve sound pressure and induce good sound quality.

FIG. 5B illustrates a process of forming the second vibration plate 64. The elastic layer 64c is formed between the first and second metal plates 64a and 64b and the first and second metal plates 64a and 64b. Through the lamination, the stiffness of the center portion (C) of the first vibration plate 62 is compensated for to prevent sound distortion. Here, only one layer of the first metal plate 64a and the second metal plate 64b may be provided.

The first and second metal plates 64a and 64b are light and rigid metal layers such as aluminum, and the aluminum layers are easily deformed during fabrication, thereby compressing a styrofoam (PS) -based material having good restoring force. Use by laminating.

In addition, the second vibrating plate 64 is preferably maintained in a thickness of 0.25-0.35 mm after compression in consideration of workability. When the thickness is smaller than 0.25 mm, it becomes difficult to control when attaching to the first vibration plate 62. For example, when the guide device is used, if the thickness is too thin, the second vibration plate 64 may not be properly guided, or when using another method, it may be difficult to find the correct position of the second vibration plate 64. On the contrary, when the thickness becomes thicker than 0.35mm, not only does it occupy a lot of space, but also the rigidity of the material of the PS material, which is the elastic layer 64c, is weakened, resulting in severe dividing and a possibility of dip in the high frequency band.

5C is a cross-sectional view of another embodiment of the diaphragm of FIG. 2. As shown in FIG. 5C, the diaphragm 63 has a central portion C1 having a planar opening at the center thereof, a side dome S formed at the edge of the central portion C1, and an edge of the side dome S. FIG. A seating portion 66 is formed in the groove. At this time, the overall shape of the diaphragm 63 may be circular.

Through the formation of the opening in the center portion C1, the weight of the center portion C1 is lightened, and when the center portion C1 and the second vibration plate 64 are adhered to each other, for example, wrinkles caused by bonds or the like are caused. prevent.

6A-6F are embodiments of a diaphragm and their performance graphs.

6A shows the structure of a circular diaphragm, and FIGS. 6B and 6C are performance graphs of the diaphragm of FIG. 6A.

As shown in FIG. 6B, as the width of the side dome S of the diaphragm decreases, the diaphragm stiffness increases to reduce the low frequency band, and as the width of the side dome S increases, the magnetic circuit becomes smaller and the force becomes smaller. As a result, the full-band sound pressure is lowered, but the stiffness is low, and the low band is reinforced again. Accordingly, it is preferable that the ratio between the radius R of the diaphragm and the width W of the side dome S in which the sound pressure is kept constant in the important sound pressure band (500 Hz to 5 kHz) is determined.

In FIG. 6C, the semicircular side dome structure S having a width W of about 10 to 20% based on the diaphragm radius R maintains a constant sound pressure in the low band (500 Hz) and the high band (5 kHz). You can see that.

FIG. 6D corresponds to the case of the diaphragm of the Oval type, and for a similar reason to that of FIG. 6B, the radius of the shortened portion R and the side dome in which the sound pressure is kept constant in the sound pressure band (500 Hz to 5 kHz) important in FIG. It can be seen that the ratio between the width W of S) is preferably determined. In the present embodiment, the calculation of the W / R ratio on the basis of the short axis is that the shortening part affects the sound quality in the Oval type because the restraining force in the diaphragm of the Oval type is greater in the short part. . Therefore, even if only the condition by the short shaft portion is satisfied in the design of the diaphragm, the condition by the long shaft portion is almost satisfied.

In FIG. 6F, a semicircular side dome S structure having a width W of about 20 to 30% based on the length R of the short axis portion is required. In this 20 ?? 30% region, the sound pressure in the low band (500 Hz) is improved, and the degree of decrease in the sound pressure in the high band (5 kHz) is reduced.

Through this size, it is possible to maximize the effective area of the side diaphragm S to optimize the width of the diaphragm. By maximizing the effective area of the diaphragm and maximizing the size of the magnet 40 of the yoke assembly described above, the size of the magnetic circuit can be maximized.

The reason for the size limitation described above is that when the width W of the side dome S is reduced from the above-described dimension, the movement of the diaphragm is reduced due to the vibration plate restraint by the side dome S, and the width of the side dome S is If W) is wider, the effective area of the central portion S decreases, so that the sound pressure is not high, the vibration width increases, the vibration space is insufficient, and the defective rate is high.

7A to 7D are embodiments of the positional relationship between the first vibration plate, the second vibration plate, and the coil part.

As shown in FIG. 7A, when attaching the second vibrating plate 64 to the center portion C of the first vibrating plate 62, a separate guide device (not shown) is used to adjust the position. To this end, a distance between the inner radius of the side dome S and the outer diameter (or edge) of the second vibration plate 64 should be secured by 0.2 mm or more.

As shown in FIG. 7B, the guide step 67 is used so that the second vibrating plate 64 is attached to the center portion c of the first vibrating plate 62 in place without using a separate guide device. Is formed. The guide terminal 67 is formed on the inner side of the side dome S, that is, formed between the side dome S and the central portion C. Accordingly, the side dome S itself serves to guide the second vibration plate 64.

As shown in FIG. 7C, the second vibrating plate 64 and the coil unit 50 must overlap a predetermined degree with the central portion C of the first vibrating plate 62 interposed therebetween. This overlapping area is the hatched area B of the second vibration plate 64, and the area not overlapping corresponds to W2. Since the position of the coil part 50 is large in the rigidity of the second vibration plate 64, 50% or more of the winding width of the coil part 50 is determined based on the outer side of the second vibration plate 64. It is desirable not to be exposed to the outside of 64). That is, it is preferable that W2 / W3 becomes less than 0.5.

As shown in FIG. 7D, an area corresponding to the coil part 50 is substantially included at the edge of the second vibration plate 64, that is, the width of the area B is substantially equal to the width of the coil part 50, or As shown in FIG. 7E, all of the regions corresponding to the coil unit 50 may be included in the second vibration plate 64, that is, the width of the region B may be the same as the width of the coil unit 50.

8 is a detailed plan view of the diaphragm.

When the first stiffness plate 62 having a small rigidity is attached to the diaphragm seating portion 26 of the frame 20 by using an adhesive bond, the first vibration plate 62 is likely to be assembled with the deformation and may be fixed. It is hard to catch. As a result, the diaphragm 60 includes guide protrusions 68a and 68b, and the guide protrusions 68a and 68b correspond to the receiving grooves 29a and 29b of the frame 20. By being formed in the diaphragm 60, the diaphragm 60 is assembled to the frame 20 by the guide protrusions 68a and 68b.

9 is a partially enlarged view of the protector and the diaphragm of FIG. 2. As shown, the radius R1 (short axis direction) of the sound emission hole 72 formed in the protector 70 is smaller than the radius R2 (short axis direction) of the second vibration plate 64 on the center portion of the diaphragm 60. It is largely formed. Of course, the same relationship must be made in the radius in the long axis direction. That is, the sound emission hole 72 formed of the protector 70 is formed to be at least equal to or larger than the size of the corresponding second vibration plate 64.

This size relationship is required, as the thickness of the central portion of the diaphragm 60, in particular, the thickness of the second vibrating plate 64 becomes thicker, the vibration space of the second vibrating plate 64 is required. Therefore, in order to prevent mechanical interference between the second vibration plate 64 and the protector 70, the sound emission hole 72 is formed to be equal to or larger than the second vibration plate 64.

10A and 10B are partially enlarged views of the coil unit. As shown in the drawing, the coil unit 50 includes a winding unit 51 in which a coil is wound, and a pair of lead wires 52 and 54 connected to the winding unit 51.

As described above, due to the maximization of the effective areas of the magnetic circuit and the diaphragm, the inner diameter of the winding part 51 can be increased. Due to the increase in the inner diameter of the winding part 51, since the winding length per turn during winding is increased, a relatively thick coil is used to maintain the same resistance and the same height, and accordingly, the length of the coil to be subjected to the force is longer, thereby increasing the electromagnetic force. To increase. This contributes linearly to the low frequency increase, and the midrange does not increase the sound pressure significantly because the weight increases as compared to the increase in electromagnetic force. Due to the increase in the inner diameter of the coil, the width of the side dome (S) is narrowed, such as the first vibration plate 62, and the low rigidity film is used to minimize the stiffness of the speaker to improve the acoustic characteristics of the low frequency band.

Lead wires 52 and 54 are respectively drawn out from the upper side of the winding part 51 of the part parallel to the long axis direction of the winding part 51, and the closest curved part of the winding part 51 is shown. Or the inflections 53, 55 at the corners. Through these inflections 53 and 55, the leader lines 52 and 54 finally go through the lead-out grooves 27 formed corresponding to the short axis direction of the frame 20, and the ends thereof are external. It is connected to the connection terminal 90 of.

The leader lines 52 and 54 travel through the space or groove 34 formed by the groove 34 when traveling above the yoke 30, and formed by the groove 28 of the frame 20. Proceed above the space or groove 28 or adjacent to or in contact with the side of the groove 28, corresponding to the inner surface of the second receiving portion 25 of the frame 20, through the withdrawal groove 27 It extends to the outside.

11 is a bottom perspective view showing the positional relationship between the diaphragm and the coil unit. As shown, the upper side surface of the winding portion 51 of FIG. 10A is mounted to the central portion C of the diaphragm 60, and the lead lines 52 and 54 drawn out from the winding portion 51 are side dome. The inflection parts 53 and 55 are located in the area | region corresponding to (S). Here, the leader lines 52 and 54 have a structure that proceeds without any contact with the diaphragm 60, that is, without coupling.

12A and 12B are performance comparison graphs between the prior art of the present invention and the present invention. 12A is a graph of comparison of sound pressure (SPL) between the prior art and the present invention, and FIG. 12B is a graph of comparison of the sound distortion (THD) between the prior art and the present invention. The diaphragm of the prior art and the diaphragm of the present invention have the same size, the prior art diaphragm is used PE series, the back volume connected to each acoustic transducer is 1cc.

As shown in FIG. 12A, in the acoustic transducer according to the present invention, a planar diaphragm laminated with high stiffness is used to minimize splitting vibration occurring as the area of the central portion of the diaphragm 60 increases, and thus, after the resonance frequency, Induces sound pressure flattening, thereby improving acoustic characteristics.

As shown in FIG. 12B, due to the maximization of the magnetic circuit, the side dome becomes narrow due to the increase in the inner diameter of the coil of the coil part 50, so that the rigidity of the acoustic transducer is obtained by using a low rigid film as the diaphragm 60. Minimize the to improve the acoustic characteristics of the low frequency band.

In the above, the present invention has been described in detail based on the embodiments of the present invention and the accompanying drawings. However, the scope of the present invention is not limited by the above embodiments and drawings, and the scope of the present invention will be limited only by the contents described in the claims below.

1 is a cross-sectional view of a microspeaker according to the prior art.

2 is a cross-sectional view of an acoustic transducer to which the diaphragm according to the present invention is applied.

3 is a perspective view of the yoke assembly of FIG. 2.

4A and 4B are perspective and plan views of the frame of FIG. 2.

5A and 5B are views illustrating a manufacturing process of the diaphragm.

5C is another embodiment of the diaphragm of FIG. 2.

6A-6F are embodiments of a diaphragm and their performance graphs.

7A to 7E are embodiments of the positional relationship between the first vibration plate, the second vibration plate, and the coil part.

8 is a detailed plan view of the diaphragm.

9 is a partially enlarged view of the protector and the diaphragm of FIG. 2.

10A and 10B are partially enlarged views of the coil unit.

11 is a bottom perspective view showing the positional relationship between the diaphragm and the coil unit.

12A and 12B are graphs of performance comparison between the present invention and the present invention of FIG.

Claims (18)

A diaphragm for an acoustic transducer, comprising a first vibrating plate formed of a central portion that is flat and a side dome formed around the central portion, and a second vibrating plate formed in a central portion of the first vibrating plate. The sound conversion device according to claim 1, wherein the central portion of the first vibration plate is composed of an opening in the center and a central mounting end in which the second vibration plate is mounted around the opening, and the central mounting end is connected to the side dome. tympanum. The vibration plate according to claim 1 or 2, wherein a step for guiding the second vibration plate is formed inside the side dome of the first vibration plate. The diaphragm for an acoustic transducer according to claim 1 or 2, wherein the side dome of the first vibration plate and the second vibration plate are spaced apart from each other by a predetermined interval. The method of claim 1 or claim 2, wherein the first vibration plate is a first sub-vibration plate comprising a thermoplastic polyurethane elastomer (TPU), polyester (PET) material , polyetherimide (PEI) material, polyether ether ketone A diaphragm for an acoustic transducer, comprising a laminate of a second sub-vibration plate including at least one of (PEEK) material and polyarylate material. 6. The diaphragm for acoustic conversion device according to claim 5, wherein the first sub diaphragm and the second sub diaphragm are sequentially positioned and laminated. The vibration plate according to claim 1 or 2, wherein the second vibration plate is composed of first and second metal layers and an elastic layer laminated between the first and second metal layers. 8. The diaphragm for acoustic conversion device according to claim 7, wherein the first and second metal layers are aluminum layers. The diaphragm for an acoustic transducer as claimed in claim 7, wherein the elastic layer is a styrofoam (PS material) layer. The diaphragm of claim 1, wherein the width of the side dome corresponds to 10 to 20% of the radius of the diaphragm or 20 to 30% of the radius of the diaphragm short axis. The diaphragm for an acoustic transducer according to claim 1 or 2, wherein the second vibration plate has a thickness of 0.25 to 0.35 mm. A diaphragm according to any one of claims 1 to 11; A coil unit mounted around the bottom of the central portion of the diaphragm; A magnetic circuit for causing magnetic flux to be bridged at right angles to at least a portion of the coil portion; A frame having a first accommodating portion accommodating a magnetic circuit at a lower side thereof and a second accommodating portion accommodating a diaphragm at an upper side thereof; Sound converting device comprising a protector for protecting the diaphragm on the upper side of the frame. The sound converting apparatus according to claim 12, wherein the coil part attached to the rear surface of the diaphragm is mounted so that a width or more of a predetermined width overlaps the second vibrating plate with the first vibrating plate interposed therebetween. The acoustic transducer as claimed in claim 1, wherein the predetermined degree is 50% or more. 13. The sound converting apparatus according to claim 12, wherein the protector has a sound emitting hole having a size equal to or wider than that of the central portion of the diaphragm or the second vibrating plate. A diaphragm assembly comprising a central portion that is a flat plate, a diaphragm having a thickness thinner than the thickness of the central portion, and a side dome formed around the central portion, and a coil portion mounted around the bottom of the central portion; A magnetic circuit for causing magnetic flux to be bridged at right angles to at least a portion of the coil portion; A frame having a first accommodating portion accommodating a magnetic circuit at a lower side thereof and a second accommodating portion accommodating the diaphragm assembly so that the coil portion is disposed between the spaced spaces at an upper side thereof; A sound converting device comprising a protector for protecting the diaphragm assembly on the upper side of the frame. 17. The acoustic transducer of claim 16, wherein the diaphragm comprises a first vibrating plate having a central portion and a side dome, and a second vibrating plate mounted on an upper surface of the central portion of the first vibrating plate. 17. The vibration plate according to claim 16, wherein the diaphragm comprises a third vibration plate made of a side dome having an opening formed at a center thereof, and having a central seating end formed around the opening, and a fourth vibration plate mounted to an upper surface of the central seating end to form a central part. A sound converter, characterized in that.

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