KR101423841B1 - Microspeaker with inner resonance chamber - Google Patents

Abstract

The present invention relates to a micro speaker having an internal resonance chamber, and more particularly, to a micro speaker having an internal resonance chamber, more specifically, to prevent a front sound generated in front of a diaphragm and a rear sound generated in the rear of a diaphragm from interfering with each other, The present invention relates to a micro speaker having an internal resonance chamber capable of reducing the size and size of a micro speaker while improving the sound quality by providing a chamber having a predetermined size inside the micro speaker.

Description

[0001] MICROSPEAKER WITH INNER RESONANCE CHAMBER [0002]

The present invention relates to a micro speaker having an internal resonance chamber, and more particularly, to a micro speaker having an internal resonance chamber, more specifically, to prevent a front sound generated in front of a diaphragm and a rear sound generated in the rear of a diaphragm from interfering with each other, The present invention relates to a micro speaker having an internal resonance chamber capable of reducing the size and size of a micro speaker while improving the sound quality by providing a chamber having a predetermined size inside the micro speaker.

In general, portable electronic devices such as portable communication terminals, notebook computers, MP3 players, and earphones are provided with micro speakers for converting electric signals into acoustic signals. These micro speakers convert electrical energy into mechanical energy by a voice coil located between the pores of the magnetic circuit by Fleming's left-hand rule that the coil in which the current is flowing is in the magnetic field.

That is, the micro speaker can be constituted by a magnet, an upper plate and a yoke to form a magnetic circuit and to link the magnetic flux of the magnetic circuit Install a voice coil in the air gap. At this time, the voice coil is adhered to the lower surface of the diaphragm to which the edge is bonded and restrained to the frame, so that attraction force and repulsive force are generated between the electromotive force generated by the input signal applied to the voice coil and the magnetic circuit, Thereby generating a sound.

As the diaphragm vibrates back and forth, the front sound is generated in front of the diaphragm and the rear sound is generated in the rear of the diaphragm. The front sound generated in front of the diaphragm is radiated forward through a front sound output port formed in front of the micro speaker and the rear sound generated from the rear of the diaphragm is transmitted through a rear sound output port formed in the rear of the micro speaker And is discharged to the rear. The present invention relates to the processing of rear sound generated behind the diaphragm. That is, since the phase difference between the front sound emitted to the front of the diaphragm and the rear sound of the diaphragm is 180 °, interference occurs when the front sound and the rear sound meet in a narrow space, so that the sound quality in the low sound area is reduced. Therefore, unless the rear sound generated from the back of the diaphragm is blocked, the low frequency range is canceled, so that the sound is heard mainly in the high frequency range, and reproduction of the natural sound becomes difficult.

Accordingly, the present invention prevents the rear sound generated from the rear of the diaphragm from interfering with the front sound emitted from the front of the diaphragm. BACKGROUND ART [0002] An encloser has conventionally been used to block the rear sound generated behind the diaphragm. The enclosure accommodates the micro speaker and serves to block the rear sound generated behind the diaphragm. At this time, if the rear sound generated from the back of the diaphragm is completely blocked, the air pressure behind the diaphragm rises and the amplitude of the diaphragm becomes narrow and the sound is shifted to the high range. Therefore, conventionally, a chamber (back volume) having a constant size is installed in the inside of the enclosure to buffer the back sound generated from the rear of the diaphragm, thereby improving bass characteristics. The larger the back volume is, the better it is for better bass characteristics. Thus, conventionally, a sufficiently large back volume is formed between the micro speaker and the enclosure. However, as the size of the enclosure is increased by the back volume, there is a problem that the thickness of the micro speaker module becomes thick. The thinner the microspeaker module is, the more advantageous it is in the field of pursuing thinning and downsizing. Therefore, it is required to limit the size of the back volume to reduce the thickness of the micro speaker module.

On the other hand, in the case of a micro speaker used in an earphone-type earphone, there is little phenomenon of interference between the rear sound and the front sound, but the rear sound is not interrupted, and a hissing sound is generated in a high- So that the sound quality is deteriorated. Accordingly, it is necessary to increase the sound pressure so that the rear sound generated at the rear of the diaphragm causes resonance, and at the same time, the resonance frequency of the high sound region is shifted to the low sound region to improve the sound quality through the even balance adjustment in the high sound region.

For example, as shown in FIG. 15, a conventional speaker module 220 (Korean Patent Laid-Open No. 10-2007-0021014) forms a back volume S20 of a predetermined size behind a speaker unit 224 So that the bass sound quality was improved by blocking the sound after. However, in the conventional back volume S20, a cable 226, which is usually installed outside the speaker unit 224 and connected to the speaker unit, is positioned inside the speaker unit 224. A solder for fixing the cable to the connection terminal of the speaker unit 224 is formed inside the back volume S20.

Accordingly, the space of the conventional back volume S20 is reduced by the cable 226 and the solder. Particularly, in the case of a micro-sized speaker such as an ear bud type earphone, since the space for installing the back volume is limited, the space reduced by the cable or the solder occupies a large amount which can not be ignored. In addition, since the conventional micro speaker can not control the size of the cable or the solder located in the back volume, the volume of the back volume varies with each product. Therefore, there is a problem that it is difficult to cause a resonance phenomenon of the rear soundproofing. That is, in order for the rear sound to resonate, the natural frequency of the diaphragm must match the natural frequency of the back volume. However, since conventional micro speakers can not precisely control the size of the back volume, resonance phenomenon is difficult to use. Accordingly, the back volume of the conventional micro speaker has been used merely for the purpose of improving the bass characteristics, and there is a limitation in effectively controlling the bass sound in the high frequency range.

SUMMARY OF THE INVENTION It is a primary object of the present invention to provide a micro speaker in which a chamber for accommodating rear sound generated from the back of a diaphragm is installed inside a micro speaker, .

Further, according to the present invention, the chamber for receiving the rear sound generated from the back of the diaphragm is installed inside the micro speaker to eliminate the influence by the cable or solder, and precisely control the size of the chamber to improve the sound quality To provide a micro speaker.

Another object of the present invention is to provide a micro speaker capable of suppressing noise in a high frequency range by controlling a resonance frequency in a high frequency band while minimizing the size of a chamber for buffering sound after being emitted from the rear of the diaphragm.

As a means for achieving the object of the present invention, a micro speaker having an internal resonance chamber according to the present invention includes:

1. A micro speaker comprising: a frame which is opened at its lower part and lower part; a magnetic part installed inside the frame and forming an air gap; and a diaphragm which vibrates up and down according to the action of a voice coil located in the air gap,

A circuit board installed at a lower end of the frame;

And an internal resonance chamber formed between the magnetic portion and the circuit board and defining a space of a predetermined size to receive a rear sound generated from the rear of the diaphragm.

In the present invention, the internal resonance chamber may include: a first through hole passing through the magnetic field portion to guide rear sound generated in the diaphragm; and a second through hole formed between the magnetic portion and the circuit board, And an inner chamber for receiving sound after being emitted.

The circuit board is electrically connected to the voice coil so as to apply an external signal to the voice coil.

The circuit board includes a second through hole for discharging the rear sound emitted from the inner chamber to the outside, and the second through hole is formed to be smaller than the first through hole.

And an installation groove into which a lead wire for electrically connecting the circuit board and the voice coil is inserted is formed on an inner surface of the frame.

Wherein the circuit board includes an upper circuit board contacting the lower surface of the magnetic field portion and a lower circuit board electrically connected to the upper circuit board and provided at a lower end of the frame, An inner chamber is formed.

The apparatus further includes a chamber case installed inside the frame, the chamber case being provided between the magnetic and circuit boards to support a lower end of the magnetic field and forming an inner chamber.

Further, on the inner surface of the frame, a projecting step for supporting the magnetic field part and forming an inner chamber of a predetermined size between the magnetic part and the circuit board is integrally formed.

And a damper plate for blocking a part of the rear sound in the first through holes and the second through holes.

The resonance frequency of the inner resonance chamber is controlled by using the diameter and length of the first through-hole and the diameter of the inner chamber.

Another embodiment of a micro speaker with an internal resonance chamber according to the present invention comprises:

A frame having upper and lower openings;

A vibration plate fixed on an upper end of the frame and having a voice coil fixed to the lower surface thereof;

An upper plate provided on the magnet, an upper plate disposed on the magnet, and a yoke member forming an air gap between the magnet and the voice coil;

A circuit board installed at a lower end of the frame to apply an external electrical signal to the voice coil;

A first through hole passing through the yoke member to guide rear sound generated in the diaphragm;

An inner chamber formed between the magnetic field unit and the circuit board and receiving sound after being emitted through the first through-hole;

And a second through hole formed in the circuit board.

The yoke member includes a yoke body forming an air gap between the yoke member and the magnet, and a lower plate supporting the lower end of the magnet. The first through hole is formed to penetrate the center of the yoke body.

According to the micro speaker having the internal resonance chamber according to the present invention, since the chamber for accommodating the rear sound generated from the rear of the diaphragm is installed inside the micro speaker instead of being installed outside the micro speaker, And thinning is possible.

In addition, since the size of each product can be controlled constantly without the presence of foreign materials such as cables or solder in the inner chamber, the resonance phenomenon is used by matching the natural frequency of the inner resonance chamber with the natural frequency of the diaphragm, Can be improved.

In particular, since the rear chamber is accommodated using a relatively small space inside chamber, the micro speaker can be miniaturized and thinned, and the resonance frequency in the high frequency band can be moved to the low frequency band to remove the noise .

1 is a sectional view showing a first embodiment of a micro speaker with an internal resonance chamber according to the present invention,
2 is an exploded perspective view showing a first embodiment of a micro speaker having an internal resonance chamber according to the present invention,
FIG. 3 is a cross-sectional view illustrating a micro-speaker having an internal resonance chamber according to the present invention and a Helmholtz resonator,
4 is a sectional view showing a second embodiment of a micro speaker with an internal resonance chamber according to the present invention,
5 is a sectional view showing a third embodiment of a micro speaker having an internal resonance chamber according to the present invention,
6 is an exploded perspective view showing a state in which lead wires of a voice coil are connected through an installation groove formed in a frame according to the present invention,
7 is a cross-sectional view showing a state where lead wires of a voice coil according to the present invention are connected,
8 is a cross-sectional view showing a fourth embodiment of a micro speaker with an internal resonance chamber according to the present invention,
9 is a sectional view showing a fifth embodiment of a micro speaker with an internal resonance chamber according to the present invention,
10 is a sectional view showing a seventh embodiment of a micro speaker with an internal resonance chamber according to the present invention,
11 is a sectional view showing an eighth embodiment of a micro speaker with an internal resonance chamber according to the present invention,
Figure 12 is a graph showing the resonant frequency of the internal resonance chamber in accordance with the present invention.
13 is a graph showing the performance of the micro speaker of Examples 1 and 2 and Comparative Example 1 measured and recorded,
14 is a graph showing the performance of the conventional micro speaker of Comparative Examples 2 and 3,
15 is a sectional view showing a structure of a conventional micro speaker.

Hereinafter, a micro speaker having an internal resonance chamber according to the present invention will be described in detail with reference to the accompanying drawings.

It is to be understood that the words or words used in the present specification and claims are not to be construed in a conventional or dictionary sense and that the inventor can properly define the concept of a term in order to describe its invention in the best possible way And should be construed in light of the meanings and concepts consistent with the technical idea of the present invention. Therefore, it should be understood that the embodiments described herein and the configurations shown in the drawings are only the most preferred embodiments of the present invention, and that various equivalents and modifications may be made thereto at the time of the present application.

1 and 2, a micro speaker 1 (hereinafter referred to as a 'micro speaker') provided with an internal resonance chamber according to the present invention includes a frame 10, A vibration system 80 composed of a diaphragm 20 fixed to the upper end of the frame 10 and a voice coil 30 attached to a lower surface of the diaphragm 20, And a circuit board 50 provided at the lower end of the frame 10. The circuit board 50 includes a magnetic circuit 40 including a yoke member 41, a magnet 42 and a yoke member 43.

An internal resonance chamber 70 is formed in the frame 10. The inner resonance chamber 70 includes a first through hole 44 formed in the magnetic portion 40 and an inner chamber 74 formed between the lower end of the magnetic portion 40 and the circuit board 50 .

The internal resonance chamber 70 blocks the rear sound generated from the rear of the diaphragm 20 and causes the rear sound to resonate. Specifically, the first through-hole 44 guides the rear sound generated in the diaphragm 20 to the inner chamber 74, and the inner chamber 74 communicates through the first through-hole 44 After it is released, it is shut off the soundproofing as well as absorbing and buffering it. The first through-hole 44 and the inner chamber 74 cause the rear sound to resonate.

That is, a chamber (back volume) is provided for blocking or blocking the sound emitted from the rear of the diaphragm 20 in the past. However, the conventional back volume is provided outside the micro speaker, that is, outside the frame 10. On the other hand, the present invention places the chamber inside the frame 10. This is referred to as the 'inner chamber' at this point.

Referring again to FIGS. 1 and 2, the frame 10 according to the present invention is formed of a cylinder having upper and lower openings. Preferably, the frame 10 is made of plastic injection. A step 11 for mounting the diaphragm 20 is formed on the upper end of the frame 10. A front sound output port 12 through which a front sound generated in front of the diaphragm 20 is radiated is formed on the frame 10. At this time, the front sound output port 12 may be formed integrally with the frame 10 or a not shown upper cover or a grill installed at the upper end of the frame 10.

The edge of the diaphragm 20 is fixed to the frame 10. The voice coil 30 is fixed to the lower surface of the diaphragm 20. The magnetic circuit 40 installed in the frame 10 includes a ring-shaped magnet 42, an upper plate 41 provided on the upper surface of the magnet 42, And a yoke member 43 which forms an air gap G at regular intervals. The yoke member 43 includes a cylindrical yoke body 45 located inside the magnet 43 and forming an air gap G and a plate-shaped lower plate 46 for supporting the lower surface of the magnet 43. [ .

The first through-hole 44 is vertically vertically formed in the center of the yoke main body 45. The first through-hole 44 is formed in a circular hole shape and is emitted to the rear of the diaphragm 20, and then guides the sound to the inner chamber 74.

The inner chamber 74 is formed between the yoke member 43 and the circuit board 50. At this time, the circuit board 50 is attached to the inside of the lower end portion of the frame 10. The circuit board 50 has a flat plate shape and is closely attached to the inner or lower surface of the frame 10 so as to seal the lower end of the frame 10.

The circuit board 50 applies an external electrical preference to the voice coil 30. In the conventional micro speaker, a circuit board for applying an external electrical signal to the voice coil is installed outside the micro speaker, that is, outside the frame. On the other hand, in the present invention, So that an inner chamber 74 is formed between the magnetic portion 40 and the circuit board 50. [0041]

As described above, according to the present invention, since the circuit board 50 is provided at the lower end of the frame 10 and the inner chamber 74 is formed between the circuit board 50 and the magnetic portion 40, Thinning and miniaturization are possible.

The inner chamber 74 prevents the rear sound from being interfered with the front sound, and smoothly vibrates the diaphragm by buffering the rear sound to improve the bass sound characteristics. The first through-hole 44 and the inner chamber 74 function as a resonance chamber resonating with the diaphragm 10. At this time, since there is no cable or soldering in the inner chamber 70, the size of the inner chamber 70 can be precisely controlled.

The resonance phenomenon is called the 'resonance phenomenon' in the field of sound processing, in particular, the phenomenon in which the amplitude of the natural frequency of an object coincides with the frequency of the external force. That is, by accurately adjusting the size of the internal resonance chamber filled with air, the natural frequency of the internal resonance chamber is matched with the natural frequency of the diaphragm, thereby increasing the amplitude of the diaphragm and improving the sound quality.

As shown in FIG. 3, the internal resonance chamber 70 of the present invention has a shape corresponding to a Helmholtz resonator shown on the left side. That is, the Helmholtz resonator is a device composed of a sealed chamber having a small hole or spout, and has the same shape as the internal resonance chamber 70 of the present invention comprising the first through hole 44 and the inner chamber 74. Therefore, by designing the size of the internal resonance chamber 70 in accordance with the natural frequency of the diaphragm 20, the rear sound generated in the diaphragm 10 can cause resonance.

For example, the resonance frequency of the internal resonance chamber 70 can be obtained from the following Helmholtz resonator equation.

Here, L ': L + 1.75a, where a is the neck radius, L is the neck length, S ₀ is the cross-sectional area of the neck, and V is the volume of the resonator.

That is, the resonance frequency can be obtained by using the radius of the first through-hole 44, the length of the first through-hole 44, and the diameter of the inner chamber 74 constituting the internal resonance chamber 70. For example, when the radius of the first through hole 44 is 0.03 mm, the length of the first through hole 44 is 0.12 mm, the diameter of the inner chamber 74 is 0.4 mm, and the sound velocity C is 344 m / s The resonance frequency of the internal resonance chamber 70 is 3.1 kHz. Therefore, when the vibration frequency of the diaphragm 20 is 3.1 kHz, the rear sound generated below the diaphragm 20 resonates in the internal resonance chamber 70. (See Fig. 12)

Hereinafter, various embodiments for forming the inner chamber 74 according to the present invention will be described. 1 and 2, the inner chamber 74 of the present invention may be formed by a chamber case 71 which is sandwiched between the yoke member 43 and the circuit board 50. That is, a cylindrical chamber case 71 in which the upper and lower parts are opened is installed between the yoke member 43 and the circuit board 50, so that the inner chamber 74 ).

The upper end of the chamber case 71 is in close contact with the yoke member 43 and the lower end of the chamber case 71 is in close contact with the circuit board 50. The circuit board 50 may be installed inside the frame 10 or may be attached to the lower end of the frame 10 and the chamber case 71 as shown in Fig. By attaching the circuit board 50 to the lower end of the frame 10, the size of the inner chamber 74 can be maximized.

When the inner chamber 70 is formed by the chamber case 71, the size of the inner chamber 70 can be uniformly formed, thereby simplifying the manufacturing process. In addition, since the yoke member 43 and the circuit board 50 are supported by the chamber case 71, they can be firmly fixed.

Also, as shown in FIG. 5, the inner chamber 74 of the present invention may be formed by the projecting step 15 formed on the frame 10a. That is, a protrusion 15 protruding inward is formed on the inner surface of the frame 10a, and a yoke member 43 is provided on the upper surface of the protrusion 15 so that the yoke member 43 and the circuit And an inner chamber 74 of a uniform size is formed between the substrates 50. Although the manufacturing process of the frame 10a can be somewhat complicated by using the projecting step 15 formed on the frame 10 as described above, since the installation of the magnetic part 40 is easy and the chamber case is not provided, The inner chamber 74 has a volume corresponding to the thickness of the inner chamber 74.

1 to 5, the circuit board 50 may have a second through hole 51 formed therein. The second through-hole 51 partially releases the rear sound of the inner chamber 74 to prevent the pressure of the inner chamber 74 from increasing. At this time, the second through-hole 51 is preferably formed to be smaller than the cross-sectional area of the first through-hole 44 in order to minimize the occurrence of the rear sound interference with the first sound.

6 and 7, an installation groove 17 through which the lead wire 31 passes is formed on the inner side surface of the frame 10 according to the present invention. The lead wire 31 is an electric wire for electrically connecting the voice coil 30 and the circuit board 50 to the circuit board 50 through an installation groove 14 formed in a direction perpendicular to the inner surface of the frame 10, And is connected to the lower surface of the substrate 50. If necessary, the circuit board 50 and the ring member 60 may be formed with grooves through which the lead wires 31 pass. At this time, the ring member 60 is for fixing the diaphragm 10. The outflow line 31 is prevented from protruding into the inner chamber 74 by inserting the lead wire 31 into the mounting groove 17 formed on the inner side of the frame 10, 71 to be easily installed.

8 is a cross-sectional view showing another embodiment of a micro speaker having an internal resonance chamber according to the present invention. As shown in the figure, the circuit board 50a of the present invention includes an upper circuit board 53 and a lower circuit board 54. [ The upper circuit board 53 contacts the bottom surface of the yoke member 43 and the lower circuit board 54 is fixed to the lower end of the frame 10. [ Accordingly, the inner chamber 74 is formed between the upper circuit board 53 and the lower circuit board 54 to a predetermined size.

The upper circuit board 53 and the lower circuit board 54 may be formed of a rigid circuit board or a flexible circuit board (FPCB). The upper circuit board 53 and the lower circuit board 54 are electrically connected by a connecting member 55. The connecting member 55 is formed of a flexible circuit board. The connection member 55 formed of the flexible circuit board can prevent the negative diffused reflection and simplify the wiring process. A third through hole 53a having a larger diameter than the first through hole 44 is formed in the upper circuit board 53. The second circuit board 54 has a second through hole 51a.

Next, FIG. 9 shows another embodiment of a micro speaker having an internal resonance chamber according to the present invention. The circuit board 50b of the present invention includes an upper circuit board portion 57 attached to the bottom surface of the yoke member 43, a lower circuit board portion 59 attached to the lower end portion of the frame 10, And a connection part 58 for electrically connecting the upper circuit board part 57 and the lower circuit board part 59. An inner chamber 74 is formed between the upper circuit board portion 57 and the lower circuit board portion 59. In the case of this embodiment, the structure is simplified because it is composed of one flexible circuit board. A third through hole 57b having a larger diameter than the first through hole 44 is formed in the upper circuit board portion 57 and a second through hole 51b is formed in the lower circuit board portion 59 do.

10 shows another embodiment of a micro speaker with an internal resonance chamber according to the present invention. A separate chamber case 71a is attached to the lower surface of the micro speaker and a circuit board 50 is attached to the lower end of the chamber case 71a. Therefore, a space is formed in the chamber case 71a to have a predetermined size, and the circuit board 50 is electrically connected to the voice coil 30. In this embodiment, a first through hole 44 is formed in the center of the magnet 42a and the lower plate 43a.

11, damper plates 61 and 62 are further installed in the first through holes 44 and the second through holes 51 of the micro speaker having the internal resonance chamber according to the present invention. . The damper plates 61 and 62 serve to block or buffer part of the rear sound. Preferably, the damper plates 61 and 62 may be formed in a mesh shape. More preferably, the damper plates 61 and 62 may be formed of a mesh cloth.

The damper plates 61 and 62 block part of the rear sound generated behind the diaphragm 20 so that the pressure behind the diaphragm 20 is kept constant. That is, if the rear sound generated from the rear of the diaphragm 20 is discharged through the first through holes 44 and the second through holes 51, the amplitude of the diaphragm 20 becomes too large, . That is, the diaphragm 20 vibrates excessively and hits the top plate, thereby generating an impact sound.

Therefore, the damper plates 61 and 62 function to suppress the amplitude of the diaphragm 20 by blocking a part of the rear soundproofing which passes through the first through holes 44 and the second through holes 51. In addition, the damper plates 61 and 62 change the natural frequency of the diaphragm 20. That is, in order to cause resonance, the resonance frequency can be found by precisely controlling the size of the internal resonance chamber 70 and using various kinds of damper plates 61 and 62.

Hereinafter, the effects of the micro speaker having the internal resonance chamber according to the present invention will be described with reference to the accompanying graphs. As shown in FIG. 13, in comparison between the first and second embodiments having the internal resonance chamber according to the present invention and the first comparative example 1 without the internal resonance chamber, the first and second embodiments having the internal resonance chamber 2 shows that the resonance frequency of the high frequency band is shifted to the low frequency band.

In the first embodiment, an inner resonance chamber 70 having a volume of 0.02 cc is formed between the magnetic circuit unit 40 and the circuit board 50 by using the chamber case 71. At this time, the effective area of the diaphragm 20 was 65 mm, and the weight of the voice coil 30 was 1.5 mg. In Example 2, the other conditions are the same as in Example 1, and the volume of the internal resonance chamber 70 is increased to 0.04 cc. On the other hand, in Comparative Example 1, the other conditions were the same as in Example 1, but the internal resonance chamber 70 was not formed.

As shown in FIG. 13, it was confirmed that the sound pressure of the resonance frequency of the high frequency band portion increases as the volume of the internal resonance chamber 70 increases to 0 cc, 0.02 cc, and 0.04 cc. Thus, when the resonance frequency of the high frequency band moves to the low frequency band and the sound pressure rises, the sibilant sound generated in the high frequency band is removed and the sound pressure in the high frequency band is raised, thereby realizing a high sound quality having a clean tone color.

Meanwhile, FIG. 14 is a graph showing performance of a conventional micro speaker. It can be seen that the conventional micro speaker increases the sound pressure in the low frequency band when the volume of the back volume in the enclosure is changed from 1cc (Comparative Example 1) to 2cc (Comparative Example 2). That is, according to the related art, when the back volume is formed outside the micro speaker, the low sound characteristics of the low sound range are improved, but the characteristics of the high sound range are hardly changed.

Therefore, in order to reproduce the sound close to the original sound through the even balance adjustment in the high-frequency range, the rear sound generated from the back of the diaphragm is cut off and resonance is caused by matching the natural frequency of the diaphragm with the natural frequency of the chamber It can be seen that it is necessary.

As described above, according to the present invention, the chamber for blocking the rear sound generated from the back of the diaphragm is installed inside the micro speaker to enable miniaturization and thinning, and also to precisely control the size of the internal resonance chamber, A damper plate is installed in the through hole to move the resonance frequency in the high frequency range to the low frequency range to eliminate the high frequency range noise, thereby realizing a high sound quality having a clean tone color.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Therefore, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. It is also to be understood that the invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

1: Micro speaker 10: Frame
12: front soundproofing outlet 13: cover
15: protruding jaw 17: installation groove
20: diaphragm 30: voice coil
31: lead wire 40:
41: plate 42: magnet
43: yoke member 44: first through hole
45: yoke body 46: lower plate
50: circuit board 51: second through hole
53: upper circuit board 53a, 57b: third through hole
54: lower circuit board 55: connecting member
57: upper circuit board portion 58: connection portion
59: lower circuit board portion 60: ring member
61, 62: damper plate 70: internal resonance chamber
71: chamber case 74: inner chamber
80: Vibrometer G: Air gap

Claims (13)

1. A micro speaker comprising: a frame which is opened at its lower part and lower part; a magnetic part installed inside the frame and forming an air gap; and a diaphragm which vibrates up and down according to the action of a voice coil located in the air gap,
And an internal resonance chamber formed between the micromirror unit and the circuit board and defining a space of a predetermined size to receive rear sound generated from the rear of the vibration plate,
The internal resonance chamber includes a first through hole passing through the center of the magnetic field portion and guiding a rear sound generated in the diaphragm, and a second through hole formed between the magnetic portion and the circuit board and being discharged through the first through- And a second through hole formed in the circuit board for discharging a rear sound emitted from the inner chamber to the outside. The micro speaker of claim 1,
delete The method according to claim 1,
Wherein the circuit board is electrically connected to the voice coil so as to apply an external signal to the voice coil.
The method of claim 3,
And the second through-hole formed in the circuit board is formed to be smaller than the first through-hole.
5. The method of claim 4,
Wherein an inner surface of the frame is formed with an installation groove into which a lead wire for electrically connecting the circuit board and the voice coil is inserted.
5. The method of claim 4,
Wherein the circuit board includes an upper circuit board contacting the lower surface of the magnetic field portion and a lower circuit board electrically connected to the upper circuit board and provided at a lower end of the frame, Wherein an inner chamber is formed. ≪ RTI ID = 0.0 > 11. < / RTI >
6. The method according to any one of claims 1 to 5,
And a chamber case provided inside the frame for supporting a lower end of the magnetic field part and provided between the magnetic part and the circuit board to form an inner chamber, .
delete 6. The method according to any one of claims 1 to 5,
Wherein the inner surface of the frame is integrally formed with a protrusion protruding to support the magnetic field portion and forming an inner chamber of a predetermined size between the magnetic portion and the circuit board.
6. The method according to any one of claims 1 to 5,
Wherein the first through hole and the second through hole are further provided with a damper plate for blocking a part of the rear sound.
6. The method according to any one of claims 1 to 5,
Wherein a resonance frequency of the internal resonance chamber is controlled by using a diameter and a length of the first through hole and a diameter of the internal chamber.
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