WO2008111711A1

WO2008111711A1 - Method for manufacturing diaphragm of acoustic transducer

Info

Publication number: WO2008111711A1
Application number: PCT/KR2007/004000
Authority: WO
Inventors: Soon Heo; Hyun-Seuk Lee; Ji-Hyun Kim; Jin-Soo Choi; Seung-Kiu Jeong
Original assignee: EM Tech Co Ltd
Current assignee: EM Tech Co Ltd
Priority date: 2007-03-15
Filing date: 2007-08-21
Publication date: 2008-09-18
Anticipated expiration: 2009-09-15
Also published as: KR20080084270A

Abstract

The present invention discloses a method for manufacturing a diaphragm (120) of an acoustic transducer which can cut down a manufacturing cost by reducing waste of a film material, and which can prevent the diaphragm (120) from being eccentrically positioned in the acoustic transducer. The method for manufacturing the diaphragm of the acoustic transducer includes the steps of cutting a polymer film into a size insertable into a molding die, positioning the cut film in the molding die, heating the molding die and pressurizing the film at the same time, cooling the molding die and removing the pressure applied to the film, and separating the molded film from the molding die. An outer guide portion (G) bent in an upward or downward direction is formed at the outer portion of the molded film. The molding die for the manufacturing method can cut down the manufacturing cost by reducing waste of the film material.

Description

METHOD FOR MANUFACTURING DIAPHRAGM OF

ACOUSTIC TRANSDUCER

Technical Field

[1] The present invention relates to a method for manufacturing a diaphragm of an acoustic transducer, and more particularly, to a method for manufacturing a diaphragm of an acoustic transducer which can cut down a manufacturing cost by reducing waste of a film material, and which can prevent the diaphragm from being eccentrically positioned in the acoustic transducer.

[2]

Background Art

[3] In general, a diaphragm applied to an acoustic transducer such as a micro speaker is made of a polymer compound film phase material with a thickness of a few to a few tens m. The diaphragm is flexible and thermally deformable.

[4] In a molding process, a polymer film which is a molding material of the diaphragm is positioned in a molding die, molded by pressurization or heating, and coupled to a guide portion of a cutting press, so that a necessary portion is cut and extracted.

[5] Fig. 1 is a perspective view illustrating a conventional acoustic transducer, Fig. 2 is an exploded perspective view illustrating the conventional acoustic transducer, and Fig. 3 is a cross-sectional view illustrating the conventional acoustic transducer.

[6] Referring to Figs. 2 and 3, the conventional acoustic transducer 10 of Fig. 1 includes a protector 11, a diaphragm 12, a coil 13, a frame 14, a yoke assembly 15, a magnet 16 and a top plate 17.

[7] As shown in Fig. 3, a side dome 12a and a center done 12b are formed at the diaphragm 12. The outer portion of the diaphragm 12 is positioned in a diaphragm seating end 14a of the frame 14, so that the diaphragm 12 and the frame 14 become concentric. Here, the outer portion of the diaphragm 12 must maintain concentricity with a coil seating end 12c on which the coil 13 is seated. The coil 13 is adhered to the coil seating end 12c, maintaining concentricity.

[8] Fig. 4 is a schematic view illustrating a process of molding a polymer film to manufacture the diaphragm of the conventional acoustic transducer, Fig. 5 is a schematic view illustrating a process of cutting the molded diaphragm of Fig. 4, and Fig. 6 is a view illustrating slant-lined loss portions generated in the process of molding and cutting the diaphragm of the conventional acoustic transducer. [9] As illustrated in Fig. 4, a molding guide portion 22 with the same size as that of a cutting guide portion of a cutting press is formed at a molding die 20.

[10] A film F which is a diaphragm material is positioned on the molding die 20. As soon as the molding die 20 is heated, the film F is pressurized by a press head PH and molded in the shape of the molding die 20. As shown in Fig. 5, the molded film F is extracted from the molding die 20, coupled to a cutting guide portion 42 of a cutting die 40 to define a cutting position, and cut in the shape of a cutting press 30 to constitute a single diaphragm. Thereafter, the diaphragm is fixedly inserted into a speaker frame.

[11] As the conventional method molds and cuts the diaphragm, a structure of deciding the cutting position must be formed on the molding die 20. This structure is the cutting guide portion 42.

[12] The outer size of the actually-used diaphragm exists in the cutting guide portion 42.

The slant-lined portions of Fig. 6 are removed after the cutting process. Therefore, the film material of the diaphragm is wasted. Moreover, when the diaphragm is not precisely cut due to thermal deformation of the ductile diaphragm material or deformation in coupling to the cutting press 30, the diaphragm is eccentrically placed in a speaker to cause a defect.

[13] In addition, when the molded diaphragn is transferred from the molding process to the cutting process, there is a difficulty in material supply. As a result, the conventional method does not lead to the production automation.

[14]

Disclosure of Invention Technical Problem

[15] Accordingly, the present invention is conceived to solve the aforementioned problems. An object of the present invention is to provide a method for manufacturing a diaphragm of an acoustic transducer, and a molding die of a diaphragm which can cut down a manufacturing cost by reducing waste of a film material.

[16] Another object of the present invention is to provide a diaphragm, a frame and a protector of an acoustic transducer, and an acoustic transducer having the same which can prevent the diaphragm from being eccentrically placed in the acoustic transducer.

[17] Yet another object of the present invention is to provide a method for manufacturing a diaphragm of an acoustic transducer which can facilitate the automation by cutting and molding the diaphragm so as to overcome a difficulty in material supply in a conventional method for manufacturing a diaphragm which molds and cuts the diaphragm.

[18]

Technical Solution

[19] In order to achieve the above-described objects, in a first aspect of the present invention, a method for manufacturing a diaphragm of an acoustic transducer includes the steps of: cutting a polymer film into a size insertable into a molding die; positioning the cut film in the molding die; heating the molding die and pressurizing the film at the same time; cooling the molding die and removing the pressure and heat applied to the film; and separating the molded film from the molding die, wherein an outer guide portion bent in an upward or downward direction is formed at the outer portion of the molded film.

[20] Preferably, the film is pressurized by a press head made of a ductile material such as silicon.

[21] In a second aspect of the present invention, a molding die of a diaphragm includes: a taper portion for easily inserting a cut film; an outer guide molding portion for forming an outer guide portion bent in an upward or downward direction at the outer portion of the film; a film seating portion for preventing non-molding of the outer guide portion and normally positioning the cut film; and a dome molding portion formed in the inward direction of the film seating portion, the molding die being provided as a positive die or a negative die.

[22] Preferably, the film seating portion of the positive die is placed higher than a center dome molding portion and a side dome molding portion.

[23] The face of the outer guide molding portion contacting the film is inclined in the outward direction of the film seating portion. Therefore, the molded film can be easily separated from the molding die. The separated film is positioned in a frame. As the film is closely adhered to an outer wall of a diaphragm seating end of the frame due to elasticity by a film inclination angle, the film can be easily coupled to a protector.

[24] In a third aspect of the present invention, a diaphragm of an acoustic transducer is manufactured by the method for manufacturing the diaphragm of the acoustic transducer, and coupled to a frame to maintain concentricity.

[25] In a fourth aspect of the present invention, a frame is coupled to the diaphragm of the acoustic transducer.

[26] In addition, a frame is coupled to the diaphragm of the acoustic transducer with an outer guide portion downwardly bent therefrom, and includes a diaphragm seating end with an arc. [27] In a fifth aspect of the present invention, a protector presses and fixes a diaphragm, wherein a rib contacting the diaphragm is formed in a right-angled or acute-angled shape. [28] Preferably, the acute-angled rib is formed higher than an outer guide portion of the diaphragm. [29] In a sixth aspect of the present invention, an acoustic transducer includes at least one of the diaphragm, the frame and the protector. [30]

Advantageous Effects [31] According to the present invention, the method for manufacturing the diaphragm of the acoustic transducer, and the molding die of the diaphragm can cut down the manufacturing cost by reducing waste of the film material. [32] According to the present invention, the diaphragm, the frame and the protector of the acoustic transducer, and the acoustic transducer having the same can prevent the diaphragm from being eccentrically placed in the acoustic transducer. [33] According to the present invention, the method for manufacturing the diaphragm can facilitate the automation by cutting and molding the diaphragm. [34]

Brief Description of the Drawings

[35] The present invention will become better understood with reference to the accompanying drawings which are given only by way of illustration and thus are not limitative of the present invention, wherein:

[36] Fig. 1 is a perspective view illustrating a conventional acoustic transducer;

[37] Fig. 2 is an exploded perspective view illustrating the conventional acoustic transducer;

[38] Fig. 3 is a cross-sectional view illustrating the conventional acoustic transducer;

[39] Fig. 4 is a schematic view illustrating a process of molding a polymer film to manufacture the diaphragm of the conventional acoustic transducer; [40] Fig. 5 is a schematic view illustrating a process of cutting the molded diaphragm of

Fig. 4; [41] Fig. 6 is a view illustrating slant-lined loss portions generated in the process of molding and cutting the diaphragm of the conventional acoustic transducer; [42] Fig. 7 is a schematic view illustrating a process of cutting a polymer film to manufacture a diaphragm of an acoustic transducer according to the present invention;

[43] Fig. 8 is a view illustrating the polymer film without loss after the cutting process of Fig. 7;

[44] Fig. 9 is an exemplary view illustrating a process of molding a diaphragn using a positive die according to the present invention;

[45] Fig. 10 is an exemplary view illustrating a process of molding a diaphragm using a negative die according to the present invention;

[46] Fig. 11 is an exemplary view illustrating a process of molding a diaphragn using another negative die according to the present invention;

[47] Fig. 12 is a cross-sectional view illustrating a positive die among the molding dies according to the present invention;

[48] Fig. 13 is a cross-sectional view illustrating a negative die among the molding dies according to the present invention;

[49] Fig. 14 is a cross-sectional view illustrating another negative die among the molding dies according to the present invention;

[50] Fig. 15 is a cross-sectional view illustrating an assembly state of an acoustic transducer according to one embodiment of the present invention;

[51] Fig. 16 is a cross-sectional view illustrating an assembly state of an acoustic transducer according to another embodiment of the present invention;

[52] Fig. 17 is a cross-sectional view illustrating an assembly state of an acoustic transdu cer according to yet another embodiment of the present invention;

[53] Fig. 18 is a cross-sectional view illustrating a protector of Fig. 15; and

[54] Fig. 19 is a cross-sectional view illustrating a protector of Fig. 16.

[55]

Best Mode for Carrying Out the Invention

[56] A diaphragm, a frame and a protector of an acoustic transducer, an acoustic transducer having the same, a method for manufacturing a diaphragm of an acoustic transducer, and a molding die of a diaphragn in accordance with preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[57] Figs. 7 to 19 are views illustrating the diaphragm, the frame and the protector of the acoustic transducer, the acoustic transducer having the same, the method for manufacturing the diaphragm of the acoustic transducer, and the molding die of the diaphragm according to the present invention.

[58] Fig. 7 is a schematic view illustrating a process of cutting a polymer film to manufacture the diaphragm of the acoustic transducer according to the present invention, Fig. 8 is a view illustrating the polymer film without loss after the cutting process of Fig. 7, Fig. 9 is an exemplary view illustrating a process of molding a diaphragm using a positive die according to the present invention, Fig. 10 is an exemplary view illustrating a process of molding a diaphragm using a negative die according to the present invention, and Fig. 11 is an exemplary view illustrating a process of molding a diaphragm using another negative die according to the present invention.

[59] Referring to Fig. 7, before a molding process, a polymer film F is positioned on a cutting die 400, and cut into a size insertable into a molding die by a cutting press 300.

[60] Therefore, as shown in Fig. 8, a loss portion is rarely generated during the cutting process. That is, a film material is not wasted.

[61] Thereafter, as illustrated in Figs. 9 to 12, the cut film F is positioned on a film seating portion 230 of a positive die 200, pressurized by a press head PH made of a ductile material such as silicon to be adhered to the positive die 200, heated, and maintained for a predetermined time. The positive die 200 is quenched, the press head PH is removed, and the molded diaphragm is extracted and transferred to a process of manufacturing a speaker.

[62] As shown in Fig. 12, the positive die 200 includes a taper portion 210 for easily inserting the film F, and the film seating portion 230 for normally positioning the film F. The film seating portion 230 is positioned higher than a done molding portion 240 composed of a center dome molding portion 242 and a side dome molding portion 244. A size of an outer guide molding portion 220 of the positive die 200 is smaller than a size of an outer wall of a diaphragm seating end of a frame and larger than a size of an outermost portion of a protector. Accordingly, the molded diaphragm can be inserted into the frame without deformation. After the molding process, an outer guide portion G of the diaphragm is formed in the dome direction of the diaphragm.

[63] According to another aspect of the present invention, as illustrated in Figs. 10 and

13, a cut film F is positioned on a film seating portion 230 of a negative die 200, pressurized by a press head PH made of a ductile material to be adhered to the negative die 200, heated, and maintained for a predetermined time. The negative die 200 is quenched, the press head PH is removed, and the molded diaphragm is extracted and transferred to a process of manufacturing a speaker.

[64] As depicted in Fig. 13, the negative die 200 includes a taper portion 210 for easily inserting the film F, and the film seating portion 230 for normally positioning the film F. The film seating portion 230 is positioned higher than an arc of a frame explained later. A size of an outer guide molding portion 220 of the negative die 200 is larger than a size of an inner wall of an arc of a diaphragm seating end of a frame and smaller than a size of an outer wall of the diaphragm seating end. As a result, the molded diaphragm can be inserted into the inner wall of the arc of the diaphragm seating end of the frame without deformation. After the molding process, an outer guide portion G of the diaphragm is formed in the downward direction of the diaphragm.

[65] According to yet another aspect of the present invention, as illustrated in Figs. 11 and 14, a cut film F is positioned on a film seating portion 230 of a negative die 200, pressurized by a press head PH made of a ductile material to be adhered to the negative die 200, heated, and maintained for a predetermined time. The negative die 200 is quenched, the press head PH is removed, and the molded diaphragm is extracted and transferred to a process of manufacturing a speaker.

[66] As shown in Fig. 14, the negative die 200 includes a taper portion 210 for easily inserting the film F. The cut film F is seated on the film seating portion 230. A predetermined depth of arc is formed outside the film seating portion 230. A size of an outer guide molding portion 220 of the negative die 200 is smaller than a size of an outer wall of a diaphragm seating end and larger than a size of an outermost portion of a protector. Accordingly, the molded diaphragm can be inserted into the frame without deformation. After the molding process, an outer guide portion G of the diaphragm is formed in the done direction of the diaphragm. The diaphragm molded by the negative die 200 has the same shape as that of the diaphragm molded by the positive die 200. However, after the molding process, when the press head PH is extracted, the diaphragm molded by the negative die 200 less breaks away.

[67] Meanwhile, preferably, the face 222 of the outer guide molding portion 220 contacting the film F is inclined in the outward direction of the film seating portion 230. Therefore, the molded film F can be easily separated from the molding die 200. In addition, since the film F is closely adhered to the outer wall of the diaphragm seating end of the frame due to elasticity by a film inclination angle, the film F can be easily coupled to the protector.

[68] Fig. 15 is a cross-sectional view illustrating an assembly state of an acoustic transducer according to one embodiment of the present invention, Fig. 16 is a cross- sectional view illustrating an assembly state of an acoustic transducer according to another embodiment of the present invention, and Fig. 17 is a cross-sectional view illustrating an assembly state of an acoustic transducer according to yet another embodiment of the present invention.

[69] Referring to Figs. 15 to 17, the acoustic transducer includes a protector 110, a diaphragm 120, a coil 130, a frame 140, a yoke assembly 150, a magnet 160 and a top plate 170.

[70] The outer portion of the diaphragm 120 is positioned on a diaphragm seating end

142 of the frame 140 to maintain concentricity with the frame 140. Here, the outer portion of the diaphragrn 120 must maintain concentricity with a coil seating end 122 on which the coil 130 is seated. The coil 130 is adhered to the coil seating end 122, maintaining concentricity.

[71] In Fig. 15, an outer guide portion G of the diaphragm 120 is inserted into an outer wall 141 of the diaphragm seating end 142 of the frame 140 to maintain concentricity. When the outer guide portion G of the diaphragrn 120 with an outward inclination angle by the molding process is inserted into the outer wall 141 of the diaphragrn seating end 142 of the frame 140 and coupled to the protector 110, the outer guide portion G of the diaphragm 120 maintains concentricity with the outer wall 141 of the diaphragm seating end 142 of the frame 140.

[72] In Fig. 16, an outer guide portion G of the diaphragm 120 is inserted into an inner wall of an arc 144 of the diaphragm seating end 142 of the frame 140 to maintain concentricity. When the outer guide portion G of the diaphragm 120 is inserted into the arc 144 of the frame 140 and coupled to the right-angled protector 110, the deformation of the diaphragm 120 is prevented, and the outer guide portion G of the diaphragm 120 maintains concentricity with the inner wall of the arc 144 of the diaphragm seating end 142 of the frame 140.

[73] In Fig. 17, an outer guide portion G of the diaphragm 120 is inserted into an outer wall 141 of the diaphragrn seating end 142 of the frame 140 to maintain concentricity. As the protruding outer guide portion G of the diaphragm 120 is pressed by a rib 112 of the acute-angled protector 110, the deformation of the diaphragm 120 is prevented.

[74] Fig. 18 is a cross-sectional view illustrating the right-angled protector according to the present invention.

[75] Referring to Fig. 18, the rib 112 of the right-angled protector 110 has a flat portion for pressing and fixing the diaphragm 120. The size of the inner portion of the protector 110 is larger than the size of the side dome starting portion of the diaphragm 120 and smaller than the size of the inner wall of the arc 144 of the diaphragrn seating end 142 of the frame 140. The size of the outermost portion of the rib 112 is smaller than the size of the outer wall 141 of the diaphragm seating end 142 of the frame 140, so that the protector 110 can be easily inserted into the frame 140.

[76] Fig. 19 is a cross-sectional view illustrating the acute-angled protector according to the present invention.

[77] As shown in Fig. 19, the rib 112 of the acute-angled protector 110 has a flat portion upwardly bent to press and fix the diaphragm 120. The size of the inner portion of the protector 110 is larger than the size of the side dome starting portion of the diaphragm 120. The size of the outermost portion of the rib 112 is smaller than the size of the outer wall 141 of the diaphragm seating end 142 of the frame 140, so that the protector 110 can be easily inserted into the frame 140.

[78]

[79] Although the preferred embodiments of the present invention have been described, it is understood that the present invention should not be limited to these preferred embodiments but various changes and modifications can be made by one skilled in the art within the spirit and scope of the present invention as hereinafter claimed.

[80]

Claims

[1] A method for manufacturing a diaphragn of an acoustic transducer, comprising the steps of: cutting a polymer film into a size insertable into a molding die; positioning the cut film in the molding die; heating the molding die and pressurizing the film at the same time; cooling the molding die and removing the pressure and heat applied to the film; and separating the molded film from the molding die, wherein an outer guide portion bent in an upward or downward direction is formed at the outer portion of the molded film.

[2] The method of claim 1, wherein the film is pressurized by a press head made of a ductile material.

[3] A molding die of a diaphragm, comprising: a taper portion for easily inserting a cut film; an outer guide molding portion for forming an outer guide portion bent in an upward or downward direction at the outer portion of the film; a film seating portion for preventing non-molding of the outer guide portion and normally positioning the cut film; and a done molding portion formed in the inward direction of the film seating portion, the molding die being provided as a positive die or a negative die.

[4] The molding die of claim 3, wherein the film seating portion of the positive die is placed higher than a center dome molding portion and a side done molding portion.

[5] The molding die of claim 3, wherein the face of the outer guide molding portion contacting the film is inclined in the outward direction of the film seating portion.

[6] A diaphragn of an acoustic transducer, which is manufactured as recited in either claim 1 or 2, and coupled to a frame to maintain concentricity.

[7] A frame of an acoustic transducer, which is coupled to the diaphragm of claim 6.

[8] A frame of an acoustic transducer, which is coupled to the diaphragm of claim 6 with an outer guide portion downwardly bent therefrom, and which comprises a diaphragm seating end with an arc.

[9] A protector of an acoustic transducer, which presses and fixes a diaphragm, a rib contacting the diaphragm being formed in a right-angled or acute-angled shape.

[10] The protector of claim 9, wherein the acute-angled rib is formed higher than an outer guide portion of the diaphragm.

[11] An acoustic transducer, comprising at least one of the diaphragm of claim 6, the frame of either claim 7 or 8, and the protector of either claim 9 or 10.