JP4823271B2 - Electromagnetic transducer - Google Patents

Description

  The present invention relates to an electromagnetic transducer for reproducing sound from an audio signal by combining a permanent magnet and a diaphragm.

In a rectangular electromagnetic transducer using a permanent magnet plate and a diaphragm, the permanent magnet plate and the diaphragm are arranged so as to face each other, and a buffer material is arranged between the permanent magnet plate and the diaphragm. There is something. The permanent magnet plate, the vibration film, and the buffer member are covered so as to be sandwiched between members such as a frame, and are attached to, for example, a speaker housing.
The permanent magnet plate has strip-shaped magnetized portions (also referred to as multipolar magnetized patterns) alternately having different polarities at regular intervals. In addition, the vibration film is opposed to a position at a boundary of different polarities of the permanent magnet plate, that is, a so-called magnetized neutral zone, and a meandering conductor pattern (meandering coil) acting as an electromagnetic coil. (Also referred to as a pattern) is provided on the surface of the vibration film.
When an audio signal current flows through the serpentine coil pattern formed on the diaphragm, the serpentine coil pattern and the multipolar magnetization pattern of the permanent magnet plate are electromagnetically coupled, and the above-described serpentine coil pattern is formed by Fleming's law. Acts and the vibrating membrane vibrates. Sound waves generated by this vibration are radiated through a sound hole formed in the permanent magnet plate and the frame, and audio reproduction is performed (see, for example, Patent Document 1).
In addition, for the purpose of preventing the conductor coil formed on the diaphragm by such vibration from being disconnected due to metal fatigue, a rigidity imparting member is provided on the diaphragm (see, for example, Patent Document 2).
Conventionally, there has been an ultra-thin speaker called “gummazone type” having a configuration similar to that of the above-described electromagnetic transducer and having a rod-shaped magnet instead of the permanent magnet plate. This bar magnet has the same polarity (N pole and N pole, or S pole and S pole), and different poles are arranged alternately in the arrangement direction perpendicular to the rod magnet. It consists of the same thing as the above. Such an ultra-thin speaker has a diaphragm formed by attaching copper or aluminum foil to a thin film made of polyester or polyimide, and etching a voice coil pattern (for example, see Non-Patent Document 1). ). According to this configuration, the sound generation operation for audio reproduction is the same as that of the electromagnetic transducer.

Japanese Patent No. 3192372 Edited by Takeo Yamamoto, Speaker System, Radio Technology, July 1977

In any of the above-described electromagnetic transducers, the vibrating membrane is a full-surface driving electromagnetic transducer in which a driving force due to the meandering coil pattern is uniformly generated on the vibration surface. In other words, the diaphragm is a piston sound source, realizing an electromagnetic transducer exhibiting flat sound pressure frequency characteristics.
However, in reality, it is difficult for the diaphragm to vibrate by generating a uniform driving force over the entire band, and in particular, as the aspect ratio of the diaphragm is increased, the diaphragm tends to generate split vibrations. As shown in FIGS. 7 (a) and 7 (b), there is a problem that abnormal noise is generated due to contact with the magnet due to the partial large amplitude of the divided vibration of the diaphragm. In addition, there is a problem that sound pressure is deteriorated due to disturbance in sound pressure frequency characteristics due to divided vibration of the vibration film.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an electromagnetic transducer that suppresses divided vibration of a diaphragm and has a flat sound pressure frequency characteristic.

  The electromagnetic transducer according to the present invention has permanent magnets alternately arranged at different magnetic poles at predetermined intervals, and opposed to the permanent magnets, and a meandering conductor coil is formed on a thin resin surface. A vibration film that electromagnetically couples with the permanent magnet by energizing the conductor coil and vibrates in the thickness direction, and a frame that supports the permanent magnet and the vibration film so as to cover the surface. The frame is supported by the frame via a tape attached so as to be divided.

  According to the electromagnetic transducer of the present invention, since the vibration film is supported via the tape attached to divide the surface of the vibration film on the portion corresponding to the antinode of the divided vibration of the vibration film, The divided vibration of the vibration film can be suppressed, and the sound pressure frequency characteristic can be flattened and stabilized.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration of an electromagnetic transducer 10 according to the present invention. FIG. 1A is an overall perspective view illustrating an external appearance of the electromagnetic transducer 10, and FIG. 1B is a configuration of the electromagnetic transducer 10. It is a disassembled perspective view shown.
2A and 2B are diagrams showing the structure of the electromagnetic transducer 10 according to the first embodiment. FIG. 2A is a cross-sectional view taken along the line AA in FIG. 1A, and FIG. It is BB sectional drawing of a).

  The electromagnetic transducer 10 includes a vibration film 11, a tape 12, permanent magnets 21 and 22, and a frame 30, and an upper frame 31 and a lower frame 32 of the frame 30 are connected to the vibration film 11 and the upper permanent magnet 21. The side permanent magnet 22 is configured to be covered.

  The vibration film 11 is composed of a base material 11a made of a thin polymer resin sheet and a conductor coil 11b formed in a meandering shape on the surface of the base material 11a, and a conductor coil (coil) 11b made of a meander pattern is It is formed by punching a metal foil by pressing or etching.

  The tape 12 is a highly heat-resistant non-woven fabric and is longer than the width of the vibration film 11. The tape 12 is bonded with an adhesive so as to divide the longitudinal direction of the surface of the vibration film 11, and is supported so that both ends of the tape 12 protruding from both sides of the vibration film 11 are sandwiched between the frames 30. Has been configured.

  Permanent magnets 21 and 22 are magnetized strip-shaped permanent magnets 21 and 22 that are alternately arranged with different magnetic poles, and a surface of the frame 30 that faces the vibration film 11 is spaced apart by an adhesive or the like. It is fixed.

  The frame 30 has a housing structure having a hollow interior, and the joint surface between the upper frame 31 and the lower frame 32 sandwiches and supports a part of the tape 12 protruding from both sides of the vibration film 11. Band-shaped permanent magnets 21 and 22 are fixed at a predetermined interval on the surface facing the vibration film 11, and a circular sound emitting hole 31a opened to the outside is provided at a predetermined interval between the permanent magnets 21 and 22. , 32a are provided at regular intervals.

Here, the relationship between the conductor coil 11 b of the vibration film 11 and the permanent magnets 21 and 22 is formed such that the conductor coil 11 b is disposed at a position facing a predetermined interval between the permanent magnets 21 and 22 fixed to the frame 30. Has been.
In addition, the tape 12 bonded to the vibration film 11 can be an electromagnetic transducer having any characteristics such as suppressing the maximum amplitude by supporting the antinode portion where the amplitude of the divided vibration of the vibration film 11 is maximum. The affixing position is determined depending on whether it is designed, and the tape 12 in the first embodiment is divided into two wavelengths corresponding to two wavelengths in which the vibration film 11 does not contact the permanent magnets 21 and 22. It is configured to be supported at 10 locations by the frame 30 using a single tape 12.

Next, the operation will be described.
FIG. 3 is a diagram illustrating the operation of the electromagnetic transducer 10 according to the first embodiment.
FIG. 4 is a frequency (Hz) -sound pressure level (dB) measurement diagram comparing the sound pressure frequency characteristics of the electromagnetic transducer 10 of the first embodiment and the conventional electromagnetic transducer.
7A and 7B are diagrams showing the divided vibration of the conventional electromagnetic transducer 110. FIG. 7A shows a vibration state when the divided vibration of the vibration film 111 is ½ wavelength, and FIG. 7B shows the vibration. FIG. 7C shows a vibration state when the divided vibration of the film 111 has one wavelength, and FIG. 7C shows a vibration state when the divided vibration of the vibration film 111 has a 3/2 wavelength.

  In the conventional electromagnetic transducer 110, as the aspect ratio of the vibration film 111 increases, for example, as shown in FIGS. Hits the permanent magnets 21 and 22 to generate abnormal noise. Further, as shown in FIG. 4, the sound pressure frequency characteristics are disturbed by the divided vibration.

  The electromagnetic transducer 10 according to Embodiment 1 employs the above-described configuration, so that the vibration film 11 is supported so as to be sandwiched between the frames 30 via both ends of the tape 12, and the large amplitude of the vibration film 11 is increased. Generate audio vibrations with multiple suppressed amplitudes. Since the plurality of amplitudes are not in contact with the permanent magnets 21 and 22, no abnormal noise is generated, and the sound pressure frequency characteristic becomes flat and stable.

  As described above, according to the electromagnetic transducer 10 of the first embodiment, both ends of the tape 12 bonded so as to divide the longitudinal direction of the surface of the thin and flexible vibration film 11 are supported by being sandwiched between the frames 30. By doing so, the partial large amplitude of the divided vibration is suppressed, so that it is possible to prevent the generation of abnormal noise and the disturbance of the sound pressure frequency characteristics.

  In addition, although the tape 12 of the electromagnetic transducer 10 of this Embodiment 1 uses the non-woven tape, it is not restricted to this, The lightweight acetate tape, cloth tape, and the influence which the vibration of the vibration film 11 does not have, A paper tape or the like may be used. Moreover, it is preferable that these tapes 12 are a material with high heat resistance at least the part which contacts the conductor coil 11b which becomes high temperature when energized.

  Moreover, since the conductor coil 11b of the vibration film 11 becomes high temperature, the tape 12 of the first embodiment is preferably arranged so that the area where the vibration coil 11 is attached to the vibration film 11 is small in contact with the conductor coil 11b. .

Embodiment 2. FIG.
5A and 5B are diagrams illustrating the structure of the electromagnetic transducer 10 according to the second embodiment. FIG. 5A is a cross-sectional view taken along line AA in FIG. 1A, and FIG. It is BB sectional drawing of a).
In the first embodiment, the vibration film 11 is supported via both ends of the tape 12 bonded so as to divide the longitudinal direction of the surface of the vibration film 11. In the second embodiment, the vibration film 11 is The vibrating membrane 11 is supported via the extended extension portion 11c. In addition, about the structure similar to the electromagnetic transducer 10 of Embodiment 1, it shall show with the same number also in a figure, and the description is abbreviate | omitted.

  The vibration film 11 is provided with an extension portion 11c extending in the short direction with a certain interval, and the extension portion 11c is supported so as to be sandwiched by the frame 30 from the thickness direction.

  As described above, the electromagnetic converter 10 of the second embodiment can suppress a partial large amplitude due to the divided vibration by adopting the above configuration, and is the same as the electromagnetic converter 10 of the first embodiment. An effect can be obtained.

  In the electromagnetic transducer 10 of the second embodiment, the vibration film 11 has been described as being supported by the frame via the extension portion 11c. However, the tape 12 of the electromagnetic transducer 10 of the first embodiment is used in combination. May be supported.

Embodiment 3 FIG.
6A and 6B are diagrams illustrating the structure of the electromagnetic transducer 10 according to the third embodiment. FIG. 6A is a cross-sectional view taken along the line AA in FIG. 1A, and FIG. It is BB sectional drawing of a).
In the third embodiment, the vibration membrane 11 is supported by the tape 12 (support portion) of the first embodiment and the extension portion 11c (support portion) extending the entire outer periphery of the vibration membrane 11 of the second embodiment. Since other configurations are the same as those of the first embodiment, the same reference numerals are used in the drawing, and description thereof is omitted.

  The vibration film 11 has an extension part 11c extending from the entire outer periphery, and the vibration film 11 is almost the same size as the surface of the frame 30, so that the extension part 11c is sandwiched between the frame 30 from the thickness direction. It is supported. Further, the tape 12 is affixed with an adhesive or the like so as to divide the longitudinal direction of the surface of the vibration film 11 at a predetermined interval, and is supported so that both ends of the tape 12 are sandwiched between the frames 30. .

  As described above, the electromagnetic transducer 10 according to the third embodiment can suppress a partial large amplitude due to the divided vibration by adopting the above configuration, and is similar to the electromagnetic transducer 10 according to the first embodiment. The effect can be obtained and the large amplitude due to the divided vibration of the vibration film 11 can be further suppressed.

  In addition, although the electromagnetic transducer 10 of Embodiment 3 was made into the extension part 11c provided in the whole outer periphery of the vibration film 11, in consideration of the drive of the vibration film 11, it is among the two sets of sides of a rectangle which opposes. One set may be spaced from the frame 30 by about 0.5 mm and may be supported by the frame 30 via another set of side extensions 11 c and the tape 12.

  As described above, the electromagnetic transducer according to the present invention is supported through the tape attached so as to divide the vibration film, and through the extension part formed by partially extending at least two opposite sides of the vibration film. Support, or a combination of tape and extension, so that it is possible to suppress the partial large amplitude due to the split vibration of the diaphragm, prevent the generation of abnormal noise, and improve the sound pressure frequency characteristics. It can be flattened and stabilized.

  In the electromagnetic transducer according to the present invention, it is described that the conductor coil 11b having a meandering pattern is formed on the surface of the vibration film 11. However, in order to convert the electric signal more faithfully into audio vibration, vibration is performed. The conductor coil 11 b may be formed on both surfaces of the film 11.

  In the electromagnetic transducer 10 of the present invention, the magnetized strip-shaped permanent magnets 21 and 22 are used. However, the magnet may be magnetized after being fixed to the frame 30, and may be magnetized at predetermined intervals. You may use the permanent magnet plate which magnetized the magnetic pole alternately.

  Further, the arrangement of the conductor coil 11b and the permanent magnets 21 and 22 formed on the vibration film 11 shown in the first to third embodiments of the present invention is not limited to this combination. A meandering shape may be formed in the direction of the longitudinal straight portion of the conductor coil 11 b, and the longitudinal direction of the strip-shaped permanent magnets 21, 22 may be disposed in the longitudinal direction of the electromagnetic transducer 10.

  In addition, although the electromagnetic transducer 10 according to the present invention is described as having the circular sound emitting holes 31a and 32b, the shape of the sound emitting holes 31a and 32a is not limited to the circular shape, and the audio generated by the vibration of the vibration film 11 is not limited. The shape and size are designed according to the purpose so that vibration can be efficiently radiated.

  The drawings shown in the embodiments of the present invention are exaggerated and enlarged for the sake of explanation, and the relationship of the thicknesses of the components may be different from the actual one.

It is (a) perspective view and (b) exploded perspective view which show the external appearance of the electromagnetic transducer 10 of this invention. It is the (a) AA sectional view taken on the line of the electromagnetic transducer 10 of Embodiment 1, and the (b) BB sectional drawing. It is an AA line sectional view showing the time of operation of electromagnetic transducer 10 of Embodiment 1. FIG. It is a frequency-sound pressure level figure which shows the sound pressure frequency characteristic of the electromagnetic transducer 10 of Embodiment 1, and the conventional electromagnetic transducer. It is the (a) AA sectional view taken on the line which shows the structure of the electromagnetic transducer 10 of Embodiment 2, and the (b) BB sectional drawing. It is the (a) AA sectional view taken on the line which shows the structure of the electromagnetic transducer 10 of Embodiment 3, and the (b) BB sectional drawing. It is the sectional view on the AA line which shows the case where the division vibration state of the conventional electromagnetic transducer is (a) 1/2 wavelength, (b) 1 wavelength, (c) 3/2 wavelength.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Electromagnetic transducer, 11 Vibration membrane, 11a Base material, 11b Conductor coil (coil), 11c Extension part, 12 Tape, 21 Upper permanent magnet, 22 Lower permanent magnet, 30 Frame, 31 Upper frame (frame), 31a, 32a Sound emission hole, 32 Lower frame (frame), 110 Conventional electromagnetic transducer, 111 Conventional vibration membrane.

Claims (5)

Permanent magnets arranged at different magnetic poles alternately at a predetermined interval;
A serpentine-shaped conductor coil is formed on a thin film-like resin surface and is opposed to the permanent magnet. When the conductor coil is energized, it is electromagnetically coupled to the permanent magnet and vibrates in the thickness direction. A vibrating membrane;
A frame that supports the permanent magnet and the diaphragm so as to cover the diaphragm,
The electromagnetic transducer according to claim 1, wherein the vibration film is supported by the frame via a tape attached so as to divide the surface thereof. The vibrating membrane has an extension that extends its outer periphery,
The electromagnetic transducer according to claim 1, wherein the electromagnetic converter is supported by a frame via a tape and the extension.   The electromagnetic transducer according to claim 2, wherein the extension part is provided by partially extending at least two opposite sides of the vibration film.   The electromagnetic transducer according to claim 2, wherein the extension portion is provided by extending the entire outer periphery of the vibrating membrane. Permanent magnets arranged at different magnetic poles alternately at a predetermined interval;
A serpentine-shaped conductor coil is formed on a thin film-like resin surface and is opposed to the permanent magnet. When the conductor coil is energized, it is electromagnetically coupled to the permanent magnet and vibrates in the thickness direction. A vibrating membrane;
A frame that supports the permanent magnet and the diaphragm so as to cover the diaphragm,
The electromagnetic transducer according to claim 1, wherein the vibration film is supported by the frame via an extension provided by partially extending at least two opposite sides thereof.

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