JP4670643B2 - Speaker diaphragm, manufacturing method thereof, and speaker using the speaker diaphragm - Google Patents

Description

  The present invention relates to a speaker employed in, for example, a mobile phone, a speaker diaphragm of the speaker, and a method for manufacturing the speaker diaphragm.

  For example, since a speaker employed in a mobile phone or the like is required to be small and light, the speaker diaphragm is made up of a first film for edges and a second film for vibration in which a part thereof is joined to the first film. It was formed by.

As a document disclosing such a prior art, for example, the following Patent Document 1 is known.
Japanese Patent Laid-Open No. 2005-294882

  The conventional example has a problem that the sound pressure characteristic is low.

  That is, also in this conventional example, in order to improve the sound pressure characteristics by reducing the weight of the speaker diaphragm, as described above, a structure in which a part of the first film for edges and the second film for vibrations are joined. However, an adhesive is applied to the joint between the first and second films, and as a result, the use of such an adhesive makes the speaker diaphragm heavier. The pressure characteristics would be lowered.

  Therefore, the present invention aims to improve sound pressure characteristics.

In order to achieve this object, the present invention makes the thickness of the second film for vibration larger than that of the first film for edges, and the second film is more laser light than the first film. The first film is made thin by integrating the first and second film joints by laser welding in the vicinity of the voice coil with a laser beam. The second film should be able to vibrate properly even when the voice coil is fixed, avoiding weighting by the adhesive and providing sound pressure characteristics. It is an improvement .

  As described above, according to the present invention, the first film for the edge is made thin so that the weight is reduced and the edge is easily elastically deformed, and the second film for vibration fixes the voice coil. It is possible to vibrate properly even in a state where the heat treatment is performed, and furthermore, by thermally welding the joint portions of the first and second films, a weight increase as a result of using a large amount of adhesive as in the past is avoided, thereby The sound pressure characteristic can be improved.

  FIG. 1 shows a speaker used in a portable device such as a cellular phone. Reference numeral 1 denotes a frame-like frame, and a concave yoke 2 is attached to the inside of the frame 1.

  A plate-like magnet 3 and a plate 4 are superposed above the yoke 2, and a magnetic gap 5 is formed between the plate 4 and the upper portion of the yoke 2.

  A cylindrical voice coil 6 is movably disposed in the magnetic gap 5, and the upper end of the voice coil 6 is fixed to the lower surface of the speaker diaphragm 7 with, for example, an adhesive (not shown).

  The speaker diaphragm 7 is composed of a ring-shaped edge first film 8 made of polyethylene naphthalate and an inverted dish-shaped vibration second film 9 made of polyimide.

  The first and second films 8 and 9 are integrated by thermally welding the inner peripheral portion of the first film 8 in the vicinity of the voice coil 6 of the second film 9 as shown in FIG.

  Specifically, as shown in FIG. 2, a part of these first and second films 8 and 9 is polymerized, and a transparent plate 10 made of quartz glass is placed as a weight with the second film 9 side up, In this state, for example, a laser beam of 405 nm was irradiated from above.

  In this case, since the second film 9 made of polyimide has a higher absorption rate of laser light than that of the first film 8 made of polyethylene naphthalate, the second film 9 generates heat, Due to this heat generation, the joining surfaces 11 of the first and second films 8 and 9 are welded.

  In this embodiment, the angle of the laser beam on the transparent plate 10 is set to 12 degrees as shown in FIG. 2, for example. However, when the laser beam passes through the transparent plate 10 and goes to the second film 9, the angle is reduced to about 10 degrees. In this state, the laser beam is likely to concentrate on the joint between the first and second films 8 and 9.

  As described above, in the embodiment of the present invention, the edge first film 8 is lightened by being thinned, and is easily elastically deformed as an edge. Further, the second film 8 for vibration is used. The film 9 can vibrate properly even when the voice coil 6 is fixed, and further, a large amount of adhesive is used as in the past by thermally welding the joint portions of the first and second films 8 and 9. As a result, weight gain can be avoided, thereby improving the sound pressure characteristics.

  Specifically, the sound pressure characteristics could be improved by about 1 dB as compared with the case where the first and second films 8 and 9 were bonded with 2.5 mg adhesive.

  FIG. 3 shows another embodiment of the present invention, in which a concave portion a is formed inward of the second film 9a to increase the strength. In this state, the voice coil 6a is attached to the lower surface of the second film 9a. It is fixed.

  FIG. 4 shows the voice coil 6b fixed below the concave portion b for increasing the strength of the second film 9b.

  In these FIG. 3, FIG. 4 and FIG. 1 as well, the strength of the first and second films 8, 9, 9a, 9b is increased by polymerization, so that the voice coils 6, 6a, It is preferable to fix 6b.

  As described above, according to the present invention, the first film for the edge is made thin so that the weight is reduced and the edge is easily elastically deformed, and the second film for vibration fixes the voice coil. It is possible to vibrate properly even in a state where the heat treatment is performed, and furthermore, by thermally welding the joint portions of the first and second films, a weight increase as a result of using a large amount of adhesive as in the past is avoided, thereby The sound pressure characteristic can be improved and applied to various devices.

Sectional drawing of one embodiment of the present invention The same enlarged sectional view Sectional drawing of other embodiment of this invention Sectional drawing of other embodiment of this invention.

Explanation of symbols

6 Voice coil 7 Speaker diaphragm 8 First film 9 Second film

Claims (6)

A first film for an edge, and a second film for vibration that is partially bonded to the first film, wherein the thickness of the second film is greater than the thickness of the first film. The second film is made of a material having a higher laser light absorption rate than the first film, and the joining portion of these first and second films is formed by a laser beam and a voice coil. By integrating by heat welding in the vicinity, the first film is thinned to reduce the weight, and the edge is easily elastically deformed, and the second film is the voice coil A loudspeaker diaphragm that can be properly vibrated even in a fixed state, and has improved sound pressure characteristics by avoiding weighting due to adhesive . The speaker diaphragm according to claim 1, wherein the first film is formed of polyethylene naphthalate, and the second film is formed of polyimide. 3. The method for manufacturing a speaker diaphragm according to claim 1, wherein a part of the first and second films is first polymerized, and then a transparent plate is interposed in the superposed portion. A method for manufacturing a speaker diaphragm that emits laser light. 3. The method for manufacturing a speaker diaphragm according to claim 1 , wherein the laser beam is irradiated from the second film side. The method for manufacturing a speaker diaphragm according to claim 4 , wherein the laser beam is applied to the second film through a transparent plate. The speaker which fixed the voice coil to the 2nd film of the speaker diaphragm as described in any one of Claim 1 or Claim 2 .

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