Patent Publication Number: US-11653133-B2

Title: Speaker unit for earphone

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit under 35 USC § 119(a) of Korean Patent Application No. 10-2021-0039900, filed on Mar. 26, 2021, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes. 
     FIELD 
     The following description relates to a speaker unit for an earphone. 
     BACKGROUND 
     The earphone includes, inside a housing, a speaker unit that generates sound waves. 
     The speaker unit may include a diaphragm, a magnet, a coil, and a plate. When electric current is applied to the coil, the coil is magnetized, and the diaphragm moves as the coil moves due to the interaction between the coil and the plate. 
     Such a speaker unit includes a configuration for reproducing low-frequency sounds and a configuration for reproducing high-frequency sounds (two-way type). In order to emit low-frequency sounds in the direction of emission of high-frequency sounds, a space between a high-frequency diaphragm and the coil is used as a sound emission path. 
     However, since the space between the high-frequency diaphragm and the coil is quite small, a loss of sound volume occurs. In addition, the sound emission path of the low-frequency sounds is limited to the radial extent of the diaphragm, and thus the intensity of sound and the reproducible sound range are limited. Also, there is a problem in that the magnetic force between the magnet and the plate is lost. 
     SUMMARY 
     This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     An objective of the present invention is to provide a speaker unit for an earphone securing the size of a diaphragm, reducing loss of sound volume, increasing the intensity of sound, and extending the reproducible sound range. 
     The objective to be achieved by the present invention is not limited to the foregoing objective, and additional objectives, which are not mentioned herein, will be readily understood by those skilled in the art from the following description. 
     According to an embodiment, there is provided a speaker unit for an earphone including a frame, a magnet, a plate fixed to the frame and in contact with the magnet, a diaphragm, a coil disposed to overlap the magnet and the plate in a radial direction, and a flexible printed circuit board (FPCB), wherein the magnet includes a first surface and a second surface arranged on an outer surface of the magnet, the first surface is a surface in contact with an inner surface of the frame, the second surface is a surface spaced apart from the inner surface of the frame, and the frame forms a first sound emission path defined by a space between the inner surface thereof and the second surface of the magnet in the radial direction. 
     The plate may include a first plate in contact with one side of the magnet and a second plate in contact with the other side of the magnet, the diaphragm may include a first diaphragm disposed in front of the first plate and a second diaphragm disposed at a rear of the second plate, the first plate may include a third surface spaced apart from the magnet in a front-to-rear direction, the first plate and the magnet may form a second emission path connected to the first sound emission path, and the second sound emission path may be defined by a space between the third surface and the magnet. 
     The first plate may include an inner portion and an outer portion which is disposed outside the inner portion and disposed to be stepped from the inner portion, and a third sound emission path defined by a space between a stepped surface between the inner portion and the outer portion, the FPCB, and the frame may be formed. 
     The frame may include a groove corresponding to the second surface and separating the second surface and the inner surface of the frame, and a guide portion in contact with the second surface. 
     The first surface and the second surface may each be a flat surface, and the first surface and the second surface may be disposed to form a right angle or an obtuse angle to each other. 
     The first surface and the second surface may be alternately disposed along the outer surface of the magnet. 
     The first surface may be a curved surface, and the second surface may be a flat surface. 
     A portion of the outer surface of the magnet may be the first surface formed as a single curved surface, and the rest of the outer surface of the magnet may be the second surface formed as a single flat surface. 
     The speaker unit may further include a first coil fixed to the first diaphragm and a second coil fixed to the second diaphragm, wherein the FPCB may include an extended portion through which a connection end of the first coil and the second coil passes, and the extended portion may include an escape portion spaced apart from the first coil. 
     The frame may further include a hole penetrating inside and outside of the frame, the speaker unit may further include an air pressure equalization path defined by a space between the frame, the magnet, and the first plate, and the air pressure equalization path may allow the outside of the frame and a front space of the first diaphragm to communicate with each other through the hole. 
     The FPCB may be attached to the third surface of the first plate. 
     Other features and aspects will be apparent from the following detailed description, the drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an exploded view of an earphone including a speaker unit according to an embodiment. 
         FIG.  2    is a perspective view of the speaker unit shown in  FIG.  1   . 
         FIG.  3    is a side cross-sectional view of the speaker unit, taken along line A-A of  FIG.  1   . 
         FIG.  4    is an exploded view of the speaker unit shown in  FIG.  1   . 
         FIG.  5    is a view of a speaker unit including a first magnet. 
         FIG.  6    is a front view of the first magnet shown in  FIG.  5   . 
         FIG.  7    is a view of a first A plate of a first plate. 
         FIG.  8    is a bottom view of the first A plate shown in  FIG.  7   . 
         FIG.  9    is a side cross-sectional view of the first A plate taken along line C-C of  FIG.  7   . 
         FIG.  10    is a view of a frame. 
         FIG.  11    is a plan view of the frame shown in  FIG.  10   . 
         FIG.  12    is a side cross-sectional view of the speaker unit taken along line A-A of  FIG.  2   . 
         FIG.  13    is a plan view of the speaker unit. 
         FIG.  14    is a side cross-sectional view of the speaker unit taken along line B-B of  FIG.  2   , showing an air pressure equalization path. 
         FIG.  15    is a view of a speaker unit from which lead-out portions of a first coil and a second coil are drawn out. 
         FIG.  16    is a perspective view of a flexible printed circuit board (FPCB) shown in  FIG.  3   . 
         FIG.  17    is a side cross-sectional view of the FPCB taken along line D-D of  FIG.  16   . 
         FIG.  18    is a view showing a state in which the lead-out portions escape through an escape portion. 
         FIG.  19    is a perspective view of a speaker unit including a first magnet according to a modification example. 
         FIG.  20    is a plan view of the first magnet shown in  FIG.  19   . 
         FIG.  21    is a view of a first plate according to a modification example. 
         FIG.  22    is a side cross-sectional view of a speaker unit showing a third sound emission path. 
         FIG.  23    is a view of a speaker unit including a FPCB and a first A plate according to a modification example. 
         FIG.  24    is a view of the FPCB to be mounted on a third surface of the first A plate. 
         FIG.  25    is a view showing a state in which the FPCB is mounted on the third surface. 
     
    
    
     Throughout the drawings and the detailed description, unless otherwise described, the same drawing reference numerals will be understood to refer to the same elements, features, and structures. The relative size and depiction of these elements may be exaggerated for clarity, illustration, and convenience. 
     DETAILED DESCRIPTION 
     The following description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. Accordingly, various changes, modifications, and equivalents of the methods, apparatuses, and/or systems described herein will be suggested to those of ordinary skill in the art. Also, descriptions of well-known functions and constructions may be omitted for increased clarity and conciseness. 
     The objects, features and advantages of the present invention will be more clearly understood from the following detailed description and preferred embodiments taken in conjunction with the accompanying drawings. It should be understood that terms or words used in the specification and the appended claims should not be construed as being limited to commonly employed meanings or dictionary definitions, but interpreted based on meanings and concepts corresponding to the technical idea of the invention, on the basis of the principle that inventors are allowed to define terms appropriately for the best explanation of their invention. Further, in the description of the present invention, detailed descriptions of related well-known functions that are determined to unnecessarily obscure the gist of the present invention will be omitted. 
     Hereinafter, a speaker unit for an earphone according to an embodiment will be described in detail with reference to the accompanying drawings. 
       FIG.  1    is an exploded view of an earphone including a speaker unit according to an embodiment;  FIG.  2    is a perspective view of the speaker unit shown in  FIG.  1   ;  FIG.  3    is a side cross-sectional view of the speaker unit, taken along line A-A of  FIG.  1   ; and  FIG.  4    is an exploded view of the speaker unit shown in  FIG.  1   . 
     Hereinafter, in the drawings, the x-axis represents the front-to-rear direction of an earphone, and the y-axis represents the radial direction of the earphone. The terms “front” or “forward” refer to a direction in which a sound is emitted through a first diaphragm  700  and a second diaphragm  800 , and the terms “rear” or “rearward” refer to the direction opposite to the front or forward direction. 
     A speaker unit  10  according to an embodiment includes both a configuration for reproducing low-frequency sounds and a configuration for reproducing high-frequency sounds (two-way type). In addition, the speaker unit  10  according to the embodiment includes a configuration for reproducing low-frequency sounds and a configuration for reproducing high-frequency sounds. 
     The speaker unit  10  according to the embodiment may be disposed in an inner space formed by a housing  20  and a cover  30 . 
     The speaker unit  10  according to the embodiment includes a frame  100 , a magnet  200 , a first plate  300 , a second plate  400 , a first coil  500 , a second coil  600 , a first diaphragm  700 , a second diaphragm  800 , and a flexible printed circuit board (FPCB)  900 . The speaker unit  10  according to the embodiment may secure a sound emission path between the frame  100  and the magnet  200  by changing the shape of the magnet  200 . 
     The frame  100  may be a cylindrical member. 
     The magnet  200  electromagnetically interacts with the first coil  500  and the second coil  600 . The magnet  200  may include a first magnet  210 , a second magnet  220 , and a third magnet  230 . The first magnet  210  may be disposed outside the second coil  600  and fixed to the frame  100 . The third magnet  230  may be disposed inside the first coil  500 . The second magnet  220  may be disposed between the first coil  500  and the second coil  600  in the radial direction y. 
     With respect to the radial direction y of the earphone, the third magnet  230  may be positioned innermost, the first magnet  210  may be positioned outermost, and the second magnet  220  may be disposed between the first magnet  210  and the third magnet  230 . 
     The first magnet  210  and the second magnet  220  may be annular members. The third magnet  230  may be a cylindrical member. 
     The first magnet  210  and the second magnet  220  are used for reproducing low-frequency sounds, and the second magnet  220  and the third magnet  230  are used for reproducing high-frequency sounds. 
     The first plate  300  that is in contact with one surface of the magnet  200  creates a magnetic field. The first plate  300  may include a first A plate  310  and a first B plate  320 . The first A plate  310  may have a ring shape. The first A plate  310  is in contact with one surface of the first magnet  210  and one surface of the second magnet  220 . The first B plate  320  may have a disk shape. The first B plate  320  is in contact with one surface of the second magnet  220 . 
     The second plate  400  in contact with the other surface of the magnet  200  creates a magnetic field. The second plate  400  may include a second A plate  410  and a second B plate  420 . The second A plate  410  may be an annular plate. The second A plate  410  is in contact with the other surface of the first magnet  210 . The second B plate  420  may have a disk shape. The second B plate  420  is in contact with one surface of the second magnet  220  and one surface of the third magnet  230 . 
     The first coil  500  is fixed to the first diaphragm  700 . When the first coil  500  moves, the first diaphragm  700  also moves in conjunction with this movement. The first coil  500  may be disposed between the second magnet  220  and the third magnet  230  in the radial direction y. Also, the first coil  500  may be disposed between the first A plate  310  and the first B plate  320  in the radial direction y. Accordingly, the first coil  500  is disposed to partly overlap the second magnet  220  and the third magnet  230  in the radial direction y. In addition, the first coil  500  is disposed to partly overlap the first plate  300  in the radial direction y. The first coil  500  may be used for reproducing high-frequency sounds. 
     The second coil  600  is fixed to the second diaphragm  800 . When the second coil  600  moves, the second diaphragm  800  also moves in conjunction with this movement. The second coil  600  may be disposed between the first magnet  210  and the second magnet  220  in the radial direction y. Also, the second coil  600  may be disposed between the second A plate  410  and the second B plate  420  in the radial direction y. Accordingly, the second coil  600  is disposed to partly overlap the first magnet  210  and the second magnet  220  in the radial direction y. In addition, the second coil  600  is disposed to partly overlap the second plate  400  in the radial direction y. The first coil  500  may be used for reproducing high-frequency sounds. 
     The first diaphragm  700  may be fixed to the FPCB  900 . The first diaphragm  700  may be used for reproducing high-frequency sounds. 
     The second diaphragm  800  may be fixed to a fixing ring  810 . The fixing ring  810  may be fixed to a grill G and the frame  100 . The second diaphragm  800  may be used for reproducing low-frequency sounds. 
     The FPCB  900  supplies an electrical signal to the first coil  500  and the second coil  600 . The FPCB  900  may be made of a soft material. 
     A first tuning portion F 1  may be disposed on the frame  100 . A second tuning portion F 2  may be disposed on the first B plate  320 . The first tuning portion F 1  and the second tuning portion F 2  may be for changing the tone or acoustic characteristics, and may be of a mesh material, including polyester, nylon, a non-woven fabric, a membrane filter, and the like. 
     A magnetic field moves to a space between the first plate  300  and the second plate  400 . When the first coil  500  and the second coil  600  are magnetized by an electric current applied thereto, the first coil  500  and the second coil  600  move according to magnetic polarities thereof. 
     That is, when the magnetic polarity of the first coil  500  is the same as that of the first plate  300 , the first coil  500  is repelled and moves away. When the magnetic polarity of the second coil  600  is the same as that of the second plate  400 , the second coil  600  is repelled and moves away. On the other hand, when the magnetic polarity of the first coil  500  is opposite to that of the first plate  300 , the first coil  500  is attracted and moves toward the first plate  300 . In addition, when the magnetic polarity of the second coil  600  is opposite to that of the second plate  400 , the second coil  600  is attracted and moves toward the second plate  400 . In this way, the first diaphragm  700  and the second diaphragm  800  move, causing air to vibrate and produce a sound. 
     The first diaphragm  700  emits a sound in the front direction as depicted by T in  FIG.  3   . The second diaphragm  800  may emit a sound through a first sound emission path as depicted by P 1  in  FIG.  3   . Also, the second diaphragm  800  may emit a sound through a second sound emission path as depicted by P 2  in  FIG.  3   . The speaker unit  10  according to the embodiment may reduce loss of the volume of the low-frequency sound by emitting the low-frequency sound in the front direction through the first sound emission path, as well as through the second sound emission path. 
       FIG.  5    is a view of the speaker unit  10  including the first magnet  210 , and  FIG.  6    is a front view of the first magnet  210  shown in  FIG.  5   . 
     Referring to  FIGS.  5  and  6   , the first magnet  310  may include a first surface  51  and a second surface S 2  that are positioned on an outer surface. The first surface  51  is a portion in contact with the inner surface of the frame  100  in the outer surface of the first magnet  210 . The second surface S 2  is a portion spaced apart from the inner surface of the frame  100  in the outer surface of the first magnet  210 . The first surface  51  and the second surface S 2  may be alternately arranged along the circumference with respect to the center of the first magnet  210 . The first surface  51  and the second surface S 2  may be arranged to form a right angle or an obtuse angle to each other. The outer surface of the first magnet  210  may have a polygonal shape. For example, the outer surface of the first magnet  210  may have an octagonal shape. 
     The second surface S 2  defines a space with the inner surface of the frame in the radial direction y to generate the first sound emission path P 1 . 
       FIG.  7    is a view of the first A plate of the first plate  300 ,  FIG.  8    is a bottom view of the first A plate  310  shown in  FIG.  7   , and  FIG.  9    is a side cross-sectional view of the first A plate taken along line C-C of  FIG.  7   . 
     Referring to  FIGS.  7  to  9   , the first A plate  310  may include at least one groove GR. The groove GR is formed to be recessed inward from an outer surface of the first A plate  310 . The groove GR is aligned with the second surface S 2  of the magnet  200  and communicates with the first sound emission path P 1 . The groove GR may be provided in plural. The number of grooves GR may correspond to the number of the second surfaces S 2 . 
     Meanwhile, the first A plate  310  may include an inner portion  311  and an outer portion  312 . The outer portion  312  is positioned outside the inner portion  311 . The outer portion  312  may be disposed to be stepped from the inner portion  311 . In addition, the first A plate  310  includes a third surface S 3 . The third surface S 3  is where the second sound emission path P 2  and a third sound emission path P 3  are formed. 
     The first A plate  310  may include a contact surface  313  in contact with one surface of the first magnet  210 . The contact surface  313  may have an annular shape. 
       FIG.  10    is a view of the frame  100 , and  FIG.  11    is a plan view of the frame  100  shown in  FIG.  10   . 
     Referring to  FIG.  10   , the frame  100  may include a guide bar  110  and a protruding portion  120 . The protruding portion  120  protrudes inward from the inner surface of the frame  100 . A plurality of protruding portions  120  may be arranged at regular intervals along the circumferential direction of the frame  100 . The guide bar  110  may be disposed between the protruding portions  120  adjacent in the circumferential direction. A space SP that forms the second sound emission path P 2  is provided between the inner surface of the frame  100  and the guide bar  100  in the radial direction y. 
     The guide bar  110  is in contact with the second surface S 2  of the first magnet  210  and supports the first magnet  210 . The guide bar  110  may be arranged in double rows. 
     The frame  100  may include a support  130 . The support  130  is disposed extending inward from the protruding portion  120 . The support  130  is in contact with a lower surface of the first magnet  210  and supports the first magnet  210 . 
       FIG.  12    is a side cross-sectional view of the speaker unit  10  taken along line A-A of  FIG.  2   . 
     Referring to  FIGS.  2  and  12   , the frame  100  forms the first sound emission path P 1  defined by the space between the inner surface  101  of the frame  100  and the second surface S 2  of the first magnet  210  in the radial direction y. In addition, one surface of the first magnet  210  and the third surface S 3  of the first A plate  310  are spaced apart from each other in the front-to-rear direction x to form the second sound emission path P 2 . The first A plate  310  is disposed such that the third surface S 3  thereof partially overlaps the first magnet  210  in the front-to-rear direction. The second sound emission path P 2  communicates with the first sound emission path P 1 . 
     A portion of the low-frequency sound produced by the second diaphragm  800  is emitted forward through the first sound emission path P 1 . Also, another portion of the low-frequency sound produced is emitted forward through the second sound emission path P 2 . The low-frequency sound is emitted forward through the first sound emission path P 1  as well as through the second sound emission path P 2 , and thus it is advantageous in that loss of low-frequency sound is reduced. 
     Since a space is secured between the first magnet  210  and the first A plate  310  in the front-to-rear direction x, there is no need to secure the sound emission path by reducing the size of the first diaphragm  700 , as depicted by L 0  in  FIG.  12   . Thus, the size of the first diaphragm  700  can be sufficiently enlarged, as depicted by L 1  in  FIG.  12   , thereby increasing the intensity of sound and extending the reproducible sound range. 
       FIG.  13    is a plan view of the speaker unit  10 . 
     Referring to  FIG.  13   , the speaker unit  10  may include a plurality of first sound emission paths P 1 . The plurality of first sound emission paths P 1  may be disposed at regular intervals along the circumferential direction of the speaker unit  10 . The plurality of first sound emission paths P 1  may be disposed to be rotationally symmetric with respect to the center Cl of the speaker unit  10 . 
       FIG.  14    is a side cross-sectional view of the speaker unit taken along line B-B of  FIG.  2   , showing an air pressure equalization path. 
     Referring to  FIG.  14   , the speaker unit  10  may include an air pressure equalization path AP defined by a space between the first magnet  210  of the frame  100  and the first A plate  310  in the radial direction y. The air pressure equalization path AP allows the space outside the ouster circumferential surface of the frame  100  to communicate with a front surface F of the first diaphragm  700  through a hole H of the frame  100 . This air pressure equalization path AP allows the space between the speaker unit  10  and the housing  20  to communicate with the space between the speaker unit  10  and the cover  30 , thereby releasing the pressure of the user&#39;s ear. 
       FIG.  15    is a view of the speaker unit  10  from which lead-out portions of the first coil  500  and the second coil  600  are drawn out;  FIG.  16    is a perspective view of the FPCB  900  shown in  FIG.  3   ;  FIG.  17    is a side cross-sectional view of the FPCB  900  taken along line D-D of  FIG.  16   ; and  FIG.  18    is a view showing a state in which the lead-out portions escape through an escape portion. 
     Referring to  FIGS.  3  and  15  to  18   , lead-out portions CL of the first coil  500  and the second coil  600  may be drawn out of the speaker unit  10 . The lead-out portions CL are located between the first diaphragm  700  and the FPCB  900 . Therefore, the first diaphragm  700  is attached to the FPCB  900 , there is a risk of disconnection due to interference between the lead-out portions CL and the FPCB  900 . To prevent such disconnection, an escape portion  920  may be provided in an extended portion  910  of the FPCB  900 . 
     The FPCB  900  may include the extended portion  910  through which the lead-out portions CL of the first coil  500  and the second coil  600  passes. The extended portion  910  includes the escape portion  920 . The escape portion  920  secures a space in which the lead-out portions CL are located, so that the lead-out portions CL and the FPCB  900  are prevented from interfering with each other between the first diaphragm  700  and the FPCB  900 . The escape portion  920  may be formed as a groove GR or a hole. In the case of the escape portion  920  formed as the groove GR, a portion of one layer  902  of the FPCB  900  consisting of two stacked layers  901  and  902  may be removed to form the groove GR. 
       FIG.  19    is a perspective view of a speaker unit  10  including a first magnet  210  according to a modification example, and  FIG.  20    is a plan view of the first magnet  210  shown in  FIG.  19   . 
     Referring to  FIGS.  19  and  20   , in the first magnet  210  according to the modification example, a first surface  51  may be a curved surface and a second surface S 2  may be a flat surface. For example, a portion of the outer surface of the first magnet  210  may be the first surface  51  formed as a curved surface, and the rest of the outer surface of the first magnet  210  may be the second surface S 2  formed as a flat surface. The first magnet  210  may have a shape in which a portion of a ring-shaped magnet  200  is cut off. Although not shown in the drawing, the first surface  51  may be a flat surface, and the second surface S 2  may be a curved surface. Alternatively, both the first and second surfaces  51  and S 2  may be flat surfaces. Alternatively, both the first and second surfaces  51  and S 2  may be curved surfaces. 
       FIG.  21    is a view of a first plate  300  according a modification example, and  FIG.  22    is a side cross-sectional view of a speaker unit  10 , showing a third sound emission path P 3 . 
     Referring to  FIGS.  21  and  22   , the first plate  300  according to the modification example includes two outer portions  312 , and a groove GR is formed between the two outer portions  312  along the circumferential direction of the first plate  300 . The groove GR corresponds to the first sound emission path P 1 . 
     The speaker unit  10  may include a third sound emission path P 3 . The third sound emission path P 3  is defined by a space between a stepped surface  314  between an inner portion  311  and the outer portions  312 , the FPCB  900 , and the frame  100 . The third sound emission path P 3  communicates with the first sound emission path P 1  and the second sound emission path P 2 . The third sound emission path P 3  expands an emission path of low-frequency sound in a region that corresponds to the first surface  51  of the first magnet  210  in the radial direction of the speaker unit  10 , thereby reducing loss of low-frequency sound. 
       FIG.  23    is a view of a speaker unit including a FPCB  900  and a first A plate  310  according to a modification example;  FIG.  24    is a view of the FPCB  900  to be mounted on a third surface S 3  of the first A plate  310 ; and  FIG.  25    is a view showing a state in which the FPCB  900  is mounted on the third surface S 3 . 
     Referring to  FIGS.  23  to  25   , according to the modification example, the FPCB  900  may be attached to the third surface S 3  of the first A plate  310 . That is, the FPCB  900  may be attached to the third surface S 3  that forms the second sound emission path P 2 , rather than to an upper surface of the first plate  310  facing the first diaphragm  700 . 
     According to the embodiment, the first sound emission path defined by a space between the frame and the magnet is created by changing the shape of the magnet, so that loss of sound volume can be reduced. 
     According to the embodiment, the second sound emission path defined by a space between the magnet and the plate is created in the front-to-rear direction to secure the expansible space of a high-frequency diaphragm in the radial direction, so that the intensity of sound can be increased and the reproducible sound range can be extended. 
     According to the embodiment, a path for air pressure equalization is formed between the magnet and the frame, so that the pressure of the user&#39;s ear can be released. 
     Although the preferred embodiments of the speaker unit have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Therefore, it should be noted that such modifications or changes belong to the claims of the present invention.