Background Art [2] In the conventional electro-acoustic transducer shown in FIG. 1, when an AC electric signal is applied to opposite ends of the voice coil to reproduce voice (sound), attraction and repulsion of the voice coil occur according to repeated exdtation of the voice coil on the magnetic drcuit formed by the yoke unit 12, the magnet 14 and the support plate 16. Therefore, the diaphragm 32 of the vibrator 30 vibrates in a thickness direction. As a result, the voice (sound) is reproduced by the vibration of the vibrator 30.

[3] The vibrator from shaking in a planar direction, thus holding the vibrator in place.

In addition, the edge support serves to prevent sound waves, emitted forwards from the diaphragm, from interfering with antiphase sound waves emitted backwards.

Furthermore, because the amplitude of the diaphragm increases when reprodudng bass sounds, superior directivity of the edge support with respect to the vibrational direction of the diaphragm is required. In addition, to prevent sound emitted from the edge support by resonance from deteriorating the quality of the electro-acoustic transducer, the edge support must have superior vibration-absorbing ability. As well, the edge support, which is attached to the drcumferential border of the diaphragm must be light (have low density) like the diaphragm.

[4] To satisfy the above-mentioned conditions of the edge support, several materials were developed. For example, coated fabric, polyurethane foam rubber or elastormer have been used as materials for the edge support. Recently, silicone or silicon resin has been gaining popularity. The silicone and silicon resin have superior thermal resistance, cold resistance, chemical resistance, weatherability, oil resistance and water resistance. Therefore, despite a change in the environment, deterioration of tone quality occurring due to a sudden amplitude change does not occur. Furthermore, despite use over a long period the edge support is not deformed so that sensitivity of sound is not deteriorated. As such, the silicone and silicon resin are suitable as a material for the edge support.

[5] However, conventional vibrators are manufactured by a vibrator manufacturing method in which, after a planar diaphragm and an edge support are independently manufactured the edge support is attached to the planar diaphragm by an adhesive agent. As such, because the edge support and the planar diaphragm are attached to each other by the adhesive agent, the conventional vibrators are problematic in that the attachment process is very inconvenient, and the attachment of the edge support to the diaphragm may be uneven. In particular, in the case of micro speakers, because a diaphragm is small, it is very difficult to attach an edge support to the diaphragm using an adhesive agent. Thus, the possibility of the occurrence of poor attachment is high.

This causes deterioration of the tone quality of the micro speaker. In addition, because the diaphragm and the edge support are attached to each other after being inde- pendently manufactured they are difficult to adapt for mass production, and pro- ductivity is decreased.

Disclosure of Invention Technical Problem [6] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a method of manufacturing a vibrator for electro-acoustic transducers in which an edge support is integrally formed around a circumferential border of a diaphragm through silicone injection molding thus improving workability in coupling the edge support to the diaphragm.

[7] A method of manufacturing a vibrator for electro-acoustic transducers which uses a vibrator manufacturing apparatus that includes a stopper to prevent silicone from flowing to undesirable portions, and a pressure part to compress the diaphragm downwards, thus preventing silicon burr from occurring on an upper or lower surface of the diaphragm.

Technical Solution [8] Mmethod of manufacturing a vibrator for electro-austic transducers which has a diaphragm that vibrates in response to an electric signal and an edge support integrally provided around a drcumferential border of the diaphragm to support the diaphragm.

The method includes: preparing the diaphragm having a predetermined shape by shaping and cutting a synthetic resin or metal film into a predetermine shape; applying a liquid primer to the diaphragm and drying the diaphragm coated with the liquid primer; inserting the diaphragm into a mold of an insert molding apparatus; and injecting silicone into the mold of the insert molding apparatus and integrally forming the edge support into a predetermined shape around the drcumferential border of the diaphragm through insert injection molding.

[9] The diaphragm may be coupled to the edge support by attaching an upper surface of the drcumferential border of the diaphragm to a lower surface of an inner rim of the edge support.

[10] The diaphragm may be coupled to the edge support by embedding the drcum- ferential border of the diaphragm in an inner surface of the edge support.

[11] In another aspect, the present invention provides an apparatus for manufacturing a vibrator for electro-aooustic transducers through insert injection molding which comprises an upper mold and a lower mold to integrally form a silicon edge support around a drcumferential border of a diaphragm that vibrates in response to an electric signal. The vibrator manufacturing apparatus includes: an insert seat part formed on an upper surface of the lower mold so that the diaphragm having a predetermined shape is inserted in the insert seat part; an edge cavity defined between a lower surface of the upper mold and the upper surface of the lower mold so as to integrally form the edge support into a predetermined shape around the drcumferential border of the diaphragm, inserted in the insert seat part, through the insert injection molding; a stopper provided at a predetermined portion under the lower surface of the upper mold to prevent silioone, injected into the edge cavity, from flowing onto an upper surface of the diaphragm inserted in the insert seat part; and a pressure part provided outside the stopper under the lower surface of the upper mold to compress the diaphragm downwards, thus preventing the silicone, injected into the edge cavity, from flowing between the insert seat part and a lower surface of the diaphragm inserted in the insert seat part.

[12] In a further aspect, the present invention provides a vibrator for electro-austic transducers, including: a diaphragm to vibrate in response to an electric signal; an edge support made of silicone and integrally formed through insert injection molding around a drcumferential border of the diaphragm; and a plurality of holes or notches provided along a planar inner rim part of the edge support which is formed around the drcumferential border of the diaphragm through the insert injection molding. The plurality of holes or notches is formed vertically through the planar inner rim part and spaced apart from each other at predetermined intervals.

[13] Brief Description of the Drawings [14] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: [15] FIG. 1 is an exploded perspective view showing a conventional micro speaker; [16] FIG. 2 is a perspective view showing a vibrator of the micro speaker of FIG. 1; and [17] FIG. 3 is a sectional view of a vibrator for electro-acoustic transducers, according to an embodiment of the present invention; [18] FIG. 4 is a flowchart of a method of manufacturing a vibrator for electro-acoustic transducers, according to an embodiment of the present invention; [19] FIG. 5 is a sectional view of a vibrator for electro-acoustic transducers, according to another embodiment of the present invention; [20] FIGS. 6 and 7 are sectional views showing an apparatus for manufacturing a vibrator for electro-acoustic transducers, according to an embodiment of the present invention; [21] FIG. 8 is a plan view showing an example of a pressure part of the vibrator manu- facturing apparatus of FIGS. 6 and 7; [22] FIG. 9 is a sectional view showing an enlargement of the pressure part of FIG. 8; [23] FIG. 10 is a plan view showing another example of the pressure part of the vibrator manufacturing apparatus according to the present invention; [24] FIG. 11 is a sectional view showing an enlargement of the pressure part of FIG. 10; [25] FIG. 12 is a perspective view of a vibrator manufactured by the apparatus having the pressure part of FIGS. 8 and 9; [26] FIG. 13 is a perspective view of a vibrator manufactured by the apparatus having the pressure part of FIGS. 10 and 11; [27] FIG. 14 is a sectional view of a vibrator for electro-acoustic transducers, according to a further embodiment of the present invention; [28] FIGS. 15 and 16 are sectional views showing an apparatus for manufacturing the vibrator of FIG. 14; [29] FIGS. 17 through 20 are sectional views showing the vibrator manufacturing method using the apparatus of the present invention; [30] FIGS. 21 through 23 are sectional views showing several examples of an in- tegration strength enhandng means formed on a planar drcumferential border part of a vibrator according to the present invention; and [31] FIG. 24 is an exploded perspective view of an electro-acoustic transducer having a vibrator, according to the present invention.

[32] Best Mode for Carrying Out the Invention [33] Hereinafter, the present invention will be described in detail with reference to the attached drawings.

[34] FIG. 3 is a sectional view of a vibrator 30 for electro-acoustic transducers, according to an embodiment of the present invention. As shown in FIG. 3, the vibrator 30 according to the embodiment of the present invention includes a diaphragm 32 which is made of a PE (polyethylene) film having a predetermined thickness, and an edge support 34 which is made of silicone and integrally provided around a drcum- ferential border 32a of the diaphragm 32.

[35] The diaphragm 32 has a drcular or elliptical plate shape and is made of synthetic resin, such as PE having a predetermined thickness, or metal, such as aluminum or titanium. A curved center part having a predetermined curvature is provided on a central portion of the diaphragm 32. The edge support 34 is integrally formed around the drcumferential border 32a of the diaphragm 32. The edge support 34 made of silicone is attached at a lower surface of an inner rim thereof to an upper surface of the drcumferential border 32a of the diaphragm 32.

[36] A method of manufacturing the vibrator 30 for electro-acoustic transducers according to an embodiment of the present invention will be described herein below with reference to the attached drawings. As shown in a flowchart of FIG. 4, in the vibrator manufacturing method according to this embodiment, the diaphragm 32 having a predetermined size is prepared at step 40 by shaping a PE film having a pre- determined thickness to form the curved center part on the central portion of the diaphragm 32 and cutting the PE film with the curved center part into a predetermined shape.

[37] Thereafter, a liquid primer is applied to the drcumferential border 32a of the diaphragm 30, formed into the predetermined shape by cutting, to enhance the in- tegration strength of silicone with the drcumferential border 32a at step 42. At step 44, the diaphragm 32, to which the liquid primer is applied is air dried for about 30 minutes.

[38] To integrally form the edge support 34 on the drcumferential 32a of the prepared diaphragm 32, the diaphragm 32 is inserted into a predetermined position of a lower mold of an insert molding apparatus at step 46, so that the lower surface of the inner rim of the edge support 34 overlaps the drcumferential border 32a of the diaphragm 32. Thereafter, upper and lower molds are assembled together so that an edge cavity (an edge support forming cavity) is defined in the mold, and then, silioone is injected into the mold of the insert molding apparatus at step 48. At step 50, the diaphragm 32, around which the edge support 34 has integrally formed through insert injection molding, is separated from the mold and thereafter, is post-processed. Then, the vibrator 30 shown in FIG. 3 is provided in which a part of the drcumferential border 32a of the diaphragm 32 is integrated with the lower surface of the inner rim of the edge support 34.

[39] As such, in the present invention, the edge support 34 having the predetermined shape is integrally formed around the drcumferential border 32a of the diaphragm 32, which is inserted in the mold of the insert molding apparatus, through insert injection molding. Therefore, the present invention does not require a process of adhering the edge support 34 to the drcumferential border 32a of the diaphragm 32 using an adhesive agent, unlike conventional vibrator manufacturing methods.

[40] FIG. 5 is a sectional view of a vibrator 30 for electro-acoustic transducers, according to another embodiment of the present invention. As shown in FIG. 5, the vibrator 30 according to this embodiment includes a diaphragm 32 which is made of a PE (polyethylene) film having a predetermined thickness. The vibrator 30 further includes an edge support 34 which is made of silicone and integrally provided around a drcumferential border of the diaphragm 32. The diaphragm 32 has a drcular or elliptical plate shape. A curved center part 32b having a predetermined curvature is provided on a central portion of the diaphragm 32. The diaphragm 32 further includes a planar drcumferential border part 32c which has a predetermined width and is provided along a drcumference of the curved center part. The edge support 34 is integrally formed around the planar drcumferential border part 32c of the diaphragm 32. The edge support 34 includes a ridge part 34a which is curved upwards, and planar inner and outer rim parts 34b and 34c which are provided along both sides of the ridge part 34a. In the vibrator 30 having the above-mentioned structure according to this embodiment, a lower surface of the planar inner rim part 34b of the edge support 34 is integrated with an upper surface of the planar drcumferential border part 32c of the diaphragm 32. As such, because the edge support 34 made of silicone has the ridge part 34a, the vibrator 30 of the present invention can flexibly accommodate vibration of the diaphragm 32. As well, the edge support 34 prevents the vibrator 30 from shaking in a planar direction, thus maintaining the correct placement of the vibrator 30.

In addition, the vibrator 30 of the present invention has superior vibration-absorbing ability.

[41] Hereinafter, an apparatus 50 for a vibrator for electro-acoustic transducers according to an embodiment of the present invention will be described with reference to the attached drawings. FIGS. 6 and 7 are sectional views showing the vibrator man- ufacturing apparatus 50 according to the present invention. As shown in FIGS. 6 and 7, the vibrator manufacturing apparatus 50 according to the present invention includes an upper mold 51 and a lower mold 52. The vibrator manufacturing apparatus 50 further includes an insert seat part 54 which is formed on an upper surface of the lower mold 52 at a predetermined depth, so that a diaphragm 32 is inserted in the insert seat part 54.

[42] The vibrator manufacturing apparatus 50 further includes a convex part 56 which is integrally provided on a central portion of the insert seat part 54 of the lower mold 52 to correspond to a curved center part 32b of the diaphragm 32. The vibrator manu- facturing apparatus 50 further includes a ridge forming protrusion 58 which is integrally provided around a drcumferential edge of the convex part 56 to define an edge cavity 53 in a predetermined shape between the upper mold 51 and the lower mold 52. A horixmtal surface part having a predetermined width is provided on both sides of the ridge forming protrusion 58 of the lower mold 52. Here, the ridge forming protrusion 58 has a drcular or elliptical plan section according to the shape of the vibrator.

[43] The vibrator manufacturing apparatus 50 further includes a ridge forming depression 59 which is provided under a lower surface of the upper mold 51, so that the edge cavity 53 is defined between the ridge forming protrusion 58 and ridge forming depression 59. A horix) ntal surface part having a predetermined width is provided on both sides of the ridge forming depression 59. The vibrator manufacturing apparatus 50 further includes a stopper 55 and a plurality of pressure parts 57 which are provided at predetermined positions inside the ridge forming depression 59. The stopper 55 is shaped as a stop wall having a predetermined width. When the upper mold 51 is assembled to the lower mold 52, a lower end of the stopper 55 comes into close contact with an upper surface of the diaphragm 32, seated in the insert seat part 54, thus perfectly closing the edge cavity 53. To satisfy this, the stopper 55 has a pre- determined height suitable to compress the diaphragm 32 downwards at a pre- determined pressure. Thus, the stopper 55 prevents silicone, injected into the edge cavity 53, from flowing onto the upper surface of the diaphragm 32, which is inserted in the insert seat part 54 of the lower mold 52.

[44] The pressure parts 57 are integrally provided outside the stopper 55 under the lower surface of the upper mold 51, that is, between the stopper 55 and the ridge forming depression 59. A rod-type pressure part 57 which is an example of the pressure parts 57 is shown in FIGS. 8 and 9. As shown in FIGS. 8 and 9, the rod-type pressure parts 57 may be shaped as a plurality of rods which are vertically provided along the stopper 55 and spaced apart from each other at regular intervals. When the upper mold 51 is assembled to the lower mold 52, lower ends of the rod-type pressure parts 57 compress downwards the upper surface of the diaphragm 32, which is inserted in the insert seat part 54, thus preventing a gap from occurring between the diaphragm 32 and the insert seat part 54. To achieve the above-mentioned purpose, each rod-type pressure part 57 has a predetermined height suitable to compress the diaphragm 32 downwards at a pre- determined pressure. To effidently compress the diaphragm 32 downwards, preferably, each rod-type pressure part 57 is spaced apart from the stopper 55 by a pre- determined distance and is adjacent to the ridge forming depression 59, such that the lower end of the rod-type pressure part 57 comes into contact with an outer portion of the drcumferential border of the diaphragm 32. The rod-type pressure parts 57 are spaced apart from each other at predetermined intervals, so that the silicone injected into the edge cavity 53 flows smoothly and evenly fills the edge cavity 53. The rod- type pressure parts 57 serve to prevent the silicone, injected into the edge cavity 53, from flowing between the insert seat part 54 and a lower surface of the diaphragm 32 inserted in the insert seat part 54.

[45] As shown in FIG. 7, when the upper mold 51 is assembled to the lower mold 52, the edge cavity 53 is defined in a predetermined shape. At this time, the ridge forming protrusion 58, formed on the upper surface of the lower mold 52, is inserted into the ridge forming depression 59, formed on the lower surface of the upper mold 51. Thus, a ridge cavity 53a is defined at a central drcumferential line of the edge cavity 53, and planar inner and outer cavities 53b and 53c are defined at both sides of the ridge cavity 53a. Here, the stopper 55 and rod-type pressure parts 57, which are vertically formed under the lower surface of the upper mold 51, are positioned in the planar inner cavity 53b. When silioone is injected into the edge cavity 53 through an inlet 68 which is provided at a predetermined position on the upper mold 51, the silioone is prevented from flowing onto the upper surface of the diaphragm 32 by the stopper 55 which is in close contact with the upper surface of the diaphragm 32. As well, the silicone is prevented from flowing between the insert seat part 54 and the lower surface of the diaphragm 32 by the rod-type pressure parts 57 that compress the drcumferential border of the diaphragm 32 at the predetermined pressure. Therefore, the vibrator man- ufacturing apparatus 50 of the present invention prevents unexpected burr from occurring on the upper and lower surface of the diaphragm 32.

[46] Another example of the pressure parts of the vibrator manufacturing apparatus 50 according to the present invention will be described herein below with reference to FIGS. 10 and 11. A plurality of protrusion-type pressure parts 57'shown in FIGS. 10 and 11 comprises a plurality of protrusions which are provided along an outer surface of the stopper 55 to be spaced apart from each other at regular intervals. The protrusion-type pressure parts 57'each extends a predetermined length outwards from an outer surface of the stopper 55. Compared with the rod-type pressure part 57 having the rod shape, the protrusion-type pressure part 57'has superior durability and simplifies a mold manufacturing process. Because the protrusion-type pressure parts 57'are spaced apart from each other at predetermined intervals, silicone injected into the edge cavity 53 smoothly flows and evenly fills the edge cavity 53. To effidently compress the diaphragm 32 downwards, preferably, each protrusiontype pressure part 57'extends as far outwards as possible, thus being adjacent to the ridge forming depression 59.

[47] FIGS. 12 and 13 are perspective views of vibrators 30 integrally having edge supports 34, according to the present invention. FIG. 12 is a perspective view of a vibrator 30 which has an integral edge support 34 and is manufactured by the vibrator manufacturing apparatus 50 having the rod-type pressure parts 57 of FIGS. 8 and 9.

FIG. 13 is a perspective view of a vibrator 30 which has an integral edge support 34 and is manufactured by the vibrator manufacturing apparatus 50 having the protrusion- type pressure parts 57'of FIGS. 10 and 11.

[48] Referring to FIG. 12, a plurality of drcular holes 45 is provided along a planar inner rim part 34b of the edge support 34, which is integrally formed around the dr- cumferential border of the diaphragm 32 through insert injection molding. The drcular holes 45 are formed by the rod-type pressure parts 57 of the vibrator manufacturing apparatus 50 of FIGS. 8 and 9 so as to be spaced apart from each other by pre- determined intervals. Furthermore, the circular holes 45 are formed vertically through the planar inner rim part 34b of the edge support 34. Referring to FIG. 13, a plurality of notches 45'is provided along a planar inner rim part 34b of the edge support 34 which is integrally formed around the circumferential border of the diaphragm 32 through insert injection molding. The notches 45'are opened towards an inside of the edge support 34 and spaced apart from each other at predetermined intervals.

Furthermore, the notches 45'are formed by the protrusion-type pressure parts 57'of the vibrator manufacturing apparatus 50 of FIGS. 10 and 11. As such, the vibrator 30 for electro-acoustic transducers according to the present invention is characterized in that the circular holes 45 and notches 45'are provided along the planar inner rim part 34b of the edge support 34 at predetermined intervals.

[49] FIG. 14 is a sectional view of a vibrator 30 for electro-acoustic transducers, according to a further embodiment of the present invention. As shown in FIG. 14, a circumferential border of the diaphragm 32 is embedded into an inner surface of an edge support 34. FIGS. 15 and 16 are sectional views showing an apparatus 50 for manufacturing the vibrator 30 of FIG. 14. As shown in FIGS. 15 and 16, a lower stopper 75 and a lower pressure part 77 are provided outside an insert seat part 54 of a lower mold 52 to correspond to a stopper 55 and a pressure part 57 of an upper mold 51. When the upper and lower molds 51 and 52 are assembled together, the lower stopper 75 and lower pressure part 77 support a lower surface of a diaphragm 32, and the stopper 55 and pressure part 57 of the upper mold 51 compress an upper surface of the diaphragm 32. At this time, a planar cavity having a predetermined size is defined around upper and lower surfaces of the circumferential border of the diaphragm 32.

Therefore, when silicone 66 is injected into an edge cavity 53 of the vibrator manu- facturing apparatus 50, the silicone 66 flows along the upper and lower surfaces of the circumferential border of the diaphragm 32. As such, in this embodiment, the vibrator 30 is formed through insert injection molding such that the circumferential border of the diaphragm 32 is embedded in the inner surface of the edge support 34. Of course, a sufficient gap is defined outside the insert seat part 54 of the lower mold 52 to allow the silicone to smoothly flow underneath the lower surface of the circumferential border of the diaphragm 32.

[50] The process of manufacturing the vibrator 30 of the present invention will be described herein below with reference to FIGS. 17 through 20. As shown in FIG. 17, the diaphragm 32 having the predetermined shape is inserted in the insert seat part 54 formed on the lower mold 52 of the vibrator manufacturing apparatus 50. Thereafter, as shown in FIG. 18, the upper mold 51 is assembled to the lower mold 51, in which the diaphragm 32 is inserted. Then, the edge cavity 53 having the predetermined shape is defined between the upper and lower molds 51 and 52. At this time, both the stopper 55 and the pressure parts 57, which are provided on the upper mold 51, compress the upper surface of the diaphragm 32 at a predetermined pressure.

[51] Thereafter, as shown in FIG. 19, silioone 66 is injected through the inlet 68, provided on the upper mold 51, at a predetermined pressure. Then, the silicone 66 passes between the pressure parts 57 and fills the edge cavity 53. Here, the stopper 55 prevents the silicone 66, injected into the edge cavity 53, from undesirably flowing toward the central portion onto the upper surface of the diaphragm 32. The pressure parts 57 prevent the silicone 66 from flowing underneath the lower surface of the diaphragm 32. After the silicone 66 is injected into the edge cavity 53, the silicone 66 is hardened over a predetermined period. Then, the edge support 34 is integrally formed around the drcumferential border of the diaphragm 32, thus providing the vibrator 30.

[52] After the vibrator 30 is completed the upper mold 51 is separated from the lower mold 52, and the vibrator 30 is removed from the lower mold 52. As such, in the present invention, the support edge 34 is integrally formed around the diaphragm 32 through insert injection molding. Accordingly, the vibrator 30 of the present invention can be manufactured into a small size and be easily adapted for mass production. Due to the above-mentioned features, the vibrator 30 can serve as a vibrator for micro speakers.

[53] In the meantime, the vibrator 30 according to each embodiment of the present invention is provided through the above-mentioned manufacturing method but such a vibrator manufacturing method may be partially modified. For example, the drcum- ferential border of the diaphragm 32, around which the edge support 34 is integrally formed may be pre-processed to enhance the integration strength of the edge support 34 with the drcumferential border of the diaphragm 32. One example of such a pre- process is the above-mentioned application of the liquid primer. Another example of the pre-process is a formation of a scratch (an integration strength enhancing means) on the drcumferential border of the diaphragm 32. As shown in FIG. 21, the scratch may be provided by forming a plurality of fine grooves 71 on the drcumferential border of the diaphragm 32. Alternatively, as shown in FIG. 22, the scratch may be provided by forming a groove 72 or a through hole 73 on the drcumferential border of the diaphragm 32. As a further alternative, as shown in FIG. 23, the scratch may be provided by forming a slit 74 having a predetermined size on the drcumferential border of the diaphragm 32. Such scratch may be formed through a separate scratching or pressing process during the vibrator manufacturing process.

[54] In the meantime, when the edge support 34 is formed around the diaphragm 32, the curved center part 32b of the diaphragm 32 may be simultaneously shaped in the vibrator manufacturing apparatus 50. In detail, as shown in FIGS. 15 and 16, a concave part 69 is provided under a central portion of the upper mold 51 to correspond to the convex part 56 provided on the central portion of the insert seat part 54 of the lower mold 52. When the upper mold 51 is assembled to the lower mold 52 after the planar diaphragm 32 is inserted in the insert seat part 54 of the lower mold 52, the convex part 56 and the concave part 69 corresponding to each other compress the planar diaphragm 32. Thereby, the curved center part 32b is shaped on the central portion of the diaphragm 32. Therefore, in this embodiment, a separate process of forming the curved center part 32b on the diaphragm 32 is unnecessary.

[55] FIG. 24 is an exploded perspective view of an electro-acoustic transducer 100 having a vibrator 30, according to the present invention. As shown in FIG. 24, the electro-acoustic transducer 100 includes a lower casing 110 which is made of synthetic resin and formed through insert injection molding with a support seat 111 provided on the lower casing 110. The electro-acoustic transducer 100 further includes a yoke unit 112 which has an elliptical shape and is seated in the support seat 111, and a magnet 114 and a support plate 116 which are sequentially seated in the yoke unit 112 to form a magnetic drcuit along with the yoke unit 112. The electro-acoustic transducer 100 further includes a voice coil 117 which is provided in a gap defined between the yoke unit 112 and the magnet 114 under a lower surface of a diaphragm 32 of the vibrator 30. The vibrator 30 is provided on the support plate 116. The vibrator 30 comprises the diaphragm 32 and an edge support 34. A planar outer rim part 34a of the edge support 34 is attached to an upper end of the lower casing 110. Here, a lower surface of the planar outer rim part 34a of the edge support 34 is attached to a stop portion of the support seat 111 of the lower casing 110. The electro-acoustic transducer 100 further includes a cover 118 which is fastened to the upper end of the lower casing 110, with a plurality of sound passage holes provided on the cover 118. Because the cover 118 is made of metal, the cover 118 is fastened to the lower casing 110 by magnetic force of both the yoke unit 112 and the magnet 114 without a separate fastening unit. By this, the planar outer rim part 34a of the edge support 34 is reliably held between the cover 118 and the upper end of the lower casing 110.

[56] In the electro-acoustic transducer 100 of the present invention, when an AC electric signal is applied to opposite ends of the voice coil to reproduce voice (sound), attraction and repulsion of the voice coil occurs according to repeated exdtation of the voice coil on the magnetic drcuit formed by the yoke unit 12, the magnet 14 and the support plate 16. Therefore, the diaphragm 32 of the vibrator 30 vertically vibrates. As a result, the voice (sound) is reproduced by the vibration of the vibrator 30.

[57]<BR> [58]<BR> [59] Industrial Applicability [60] As described above, the present invention provides a method of manufacturing a vibrator for electro-acoustic transducers in which an edge support is integrally formed around a drcumferential border of a diaphragm through silicone injection molding, so that the diaphragm and the edge support are coupled to each other without a separate coupling process, thus preventing reduction in workability that results from the separate process of coupling the edge support to the diaphragm.

[61] Furthermore, an apparatus for manufacturing the vibrator for electro-acoustic transducers according to the present invention includes a stopper to prevent silicone, injected into an edge cavity, from undesirably flowing onto an upper surface of the diaphragm inserted in an insert seat part of a lower mold. As well, the vibrator manu- facturing apparatus further includes a pressure part to prevent the silicone from flowing underneath a lower surface of the diaphragm. Therefore, the vibrator manu- facturing apparatus of the present invention prevents unexpected burr from occurring on the upper and lower surface of the diaphragm thus enhandng tone quality.

[62] Moreover, in the vibrator for electro-acoustic transducers according to the present invention, a liquid primer is applied to a circumferential border of the diaphragm or an integration strength enhandng means, such as fine grooves, a groove, a through hole or a slit, is formed on the drcumferential border of the diaphragm. Accordingly, it is effective to enhance the integration strength of the diaphragm with the support edge.

[63] In addition, in another method for manufacturing a vibrator for electro-acoustic transducers according to the present invention, a process of shaping a curved center part on a central portion of a diaphragm is simultaneously executed with a process of integrally forming an edge support around the diaphragm through insert injection molding by another vibrator manufacturing apparatus. Therefore, in this case, a separate diaphragm shaping process is unnecessary. [64] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appredate that various modi- fications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. <BR> <BR> <P>[65]<BR> [66]<BR> [67]