JPH1175291A - Electroacoustic transducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the generation of unnecessary resonance at a main vibration part and to suppress sound distortion by forming partition walls inside projections of a diaphragm and in the opposite direction from the projections and making the projection parts larger in rigidity orthogonal to their length. SOLUTION: The diaphragm 70 consists of peak parts 7a1 to 7a7, a plane part 7b, and an outer peripheral part 7c. To increase the rigidity of the peak parts 7a1 to 7a7, ribs all to a47 are provided inside the peak parts 7a1 to 7a7. Those ribs all to a47 are formed when the diaphragm 70 is molded integrally and the ribs all to a47 are as thick as the peak parts 7a1 to 7a7. Thus, the peak parts 7a1 to 7a7 are increased in rigidity to reduce the generation of unnecessary resonance (split vibration) that the main vibration part 7A mounted with those peak parts 7a1 to 7a7 generates when its entire surface vibrates uniformly in the front-rear direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroacoustic transducer which is a flat speaker.

[0002]

2. Description of the Related Art FIG. 3 is a view for explaining a conventional electroacoustic transducer. FIG. 3A is a front view of the electroacoustic transducer, and FIG. Sectional view, FIG.
FIGS. 4A and 4B are diagrams for explaining a diaphragm constituting a conventional electroacoustic transducer, FIG. 4A is a front view of the diaphragm, and FIG. It is the longitudinal cross-sectional view which cut | disconnected longitudinally.

As shown in FIGS. 3 (A) and 3 (B), an overall-drive thin speaker unit A, which is an electroacoustic transducer, includes a frame 1, a rear plate 2, a magnet 3, a pole piece 4, a guide pin 5, a boiler. A coil 6, a diaphragm (diaphragm) 7, a damper 8, and an edge 9 are roughly constituted. The area of the diaphragm can be increased by increasing the number of combinations (segments) of the magnet 3, the boil coil 6, and the diaphragm (diaphragm) 7. The dimensions of the speaker unit A are, for example, a thickness of 25 mm,
The width is 115 mm, the height is 136 mm, the maximum amplitude is 10 mmp-p (at 600 gf), and the withstand power is 60 W.

The frame 1 is a frame formed of a heat-resistant resin such as a super heat-resistant ABS resin. The frame 1 is screwed and fixed to a speaker cabinet (not shown) via screw holes 1A to 1D provided at four corners thereof (the dimensions of the speaker cabinet are, for example, a thickness of 60 mm and a width of 1 mm).
20 mm, height 500 mm). A rear plate 2 is firmly screwed and fixed to the entire rear side of the frame 1, while four dampers 8 are adhesively fixed to four corners on the front side (diaphragm 7 side). The diaphragm 7 is formed by these four dampers 8.
The four corners are supported so as to freely vibrate.

The rear plate 2 is formed of a metal plate such as iron, and is a base plate for fixing the longitudinal magnets 3 having the longitudinal pole pieces 4 adhered to the upper surface thereof. A large number of air vent slits / holes are provided on the entire rear side of the rear plate 2 and a pair of speaker terminals connected to the start and end of the boil coil 6 are provided (neither is shown). On the other hand, both ends of the long pole piece 4 to which the long magnet 3 is adhered are screwed and fixed with the guide pins 5 on the front side (the diaphragm 7 side) of the rear plate 2 as described above. In the illustrated example, seven longitudinal magnets 3 are provided in parallel with each other.

The magnet 3 is a magnet obtained by sintering ferrite such as strontium ferrite. As described above, when this magnet 3 is fixed to the front side (diaphragm 7 side) of the rear plate 2, one surface of the magnet 3 in contact with the rear plate 2 becomes the N pole, while the magnet 3 in contact with the pole piece 4. The magnet 3 is magnetized so that the other surface (the diaphragm 7 side) of the magnet 3 becomes an S pole. The dimensions of the magnet 3 are, for example, 80 mm in length, 5 mm in width, and 8 mm in thickness.

The pole piece 4 is made of a metal plate such as iron, and has a pair of screw holes at both ends for fixing the magnet 3 to the rear plate 2. The boil coil 6 is provided with top portions 7a1 to 7a7 constituting the diaphragm 7.
Is a coated copper wire sequentially wound around each. As described above, the start and end (not shown) of the boil coil 6 are connected to a pair of speaker terminals provided on the rear plate 2 respectively.

The diaphragm (diaphragm) 7 is made of a polyimide (PI) film that withstands heat generated by the boiler coil 6 and has excellent mechanical properties as a diaphragm, and is integrally molded. Also, in order to reduce the weight of the diaphragm 7,
Although it is necessary to make the diaphragm itself as thin as possible, the thickness of the diaphragm 7 used here was 75 μm. As described above, the diaphragm 7 is mounted on the magnet 3 and the pole piece 4 fixed on the rear plate 2, and the periphery thereof is positioned and fixed to the frame 1 by an edge 9 made of urethane or the like. The specific configuration of the diaphragm 7 will be described later.

The damper 8 supports the vibration plate 7 so as to be able to vibrate freely, and is made of a thermoplastic resin such as polycarbonate, which is a material having high spring properties, impact resistance and heat resistance. In order to obtain a maximum amplitude of 10 mmpp in a limited space, a multi-stage leaf spring structure is used. Since the dampers 8 are fixed to the four corners of the frame 1, the displacement of each damper 8 is 150 gf and the displacement is 10 mm pp. This load is supported by a four-end support beam structure. Further, the structure is such that the tensile load in the plane direction of the diaphragm 7 is received by the connecting portion at the center of the damper 8. The beam structure is arranged in a fan shape to save space.

The above-mentioned diaphragm 7 is shown in FIG.
As shown in (B), the top part 7a1 is composed of a plurality of top parts 7a1 to 7a7, a plane part 7b, and an outer peripheral part 7c.
1 to 7a7, the flat portion 7b, and the outer peripheral portion 7c are integrally formed. In addition, the top portions 7a1 to 7a7 have a convex shape (raised) from the back side (the rear plate 2 side) of the vibrating plate 7 toward the front side.
The top portions 7a1 to 7a7 are integrally formed as a main vibrating portion 7A. Here, vibrating plate 7
Is the front side of the thin speaker unit A driven entirely. The tops 7a1 to 7a7 are in the longitudinal direction of the diaphragm 7 (FIG. 3).
(A), seven vertical lines in FIG. 4 (A), and the cross-sectional shape of each of the tops 7a1 to 7a7 is A- in FIG. It has a convex shape (semi-cylindrical shape, semi-cylindrical shape) cut along the line A '. An outer peripheral portion 7c is formed around the main vibrating portion 7A.

By supplying an audio signal (driving current) between the pair of speaker terminals of the thin speaker unit A having the above-described configuration, the tops 7a1 to 7a7 of the diaphragm 7 move relative to the paper surface. The whole surface vibrates uniformly before and after.

[0012]

As described above, the diaphragm (diaphragm) 7 is made as thin as possible to reduce the weight of the diaphragm itself and is integrally molded with a polyimide film. It is extremely difficult to keep the thickness of each part of the diaphragm 7 uniform. In particular, seven tops 7a
The width of the tops 7a1-7a7, which is perpendicular to the longitudinal direction (vertical direction in FIGS. 3A and 4A), is shorter than the thickness in the longitudinal direction (FIGS. 3A and 4A). FIG. 4 (A)
There is a disadvantage that the thickness of the sheet (middle, left and right directions) becomes thin. For this reason, the mechanical strength in the lateral direction of each of the top portions 7a1 to 7a7 was inferior. As a result, when an audio signal (drive current) of a relatively large level is supplied to drive the full-drive thin speaker unit A, the top portions 7a1 to 7a7 do not vibrate integrally as the main vibrating portion 7A. Each of the peaks 7a1 to 7a7 does not vibrate uniformly, but vibrates separately, and the adjacent peaks may collide with each other and generate an abnormal sound due to the divided vibration (a so-called “buzzy sound”).

As a result, in the above-described conventional full-drive thin speaker unit A, especially in the middle band (about 800 Hz to about 4 Hz).
(kHz), the sound pressure has a maximum dip of 40 dB, and the level fluctuation is much larger than other sound ranges. For this reason, a flat sound pressure frequency characteristic could not be obtained in the middle range.

According to the present invention, in order to solve the problem that a flat sound pressure cannot be obtained in all frequency bands, a plurality of partition walls a11 to a47 are formed inside each of the tops 7a1 to 7a7 of the diaphragm. By increasing the rigidity in the direction perpendicular to the longitudinal direction of the apex, even if the apex portions 7a1 to 7a7 are integrally vibrated as the main vibrating portion 7A, unnecessary resonance in the main vibrating portion 7A can be prevented. It is an object of the present invention to provide an electroacoustic transducer in which generation is reduced and acoustic distortion is suppressed.

[0015]

To solve the above-mentioned problems, the present invention provides an electro-acoustic transducer having the following constitutions (1) and (2).

(1) As shown in FIGS. 1 and 2, an electroacoustic transducer having a planar diaphragm 70 in which a plurality of elongated protrusions (tops) 7a1 to 7a7 are formed in parallel. (Fully driven thin speaker unit) AA, which is inside the projections (tops) 7a1 to 7a7 and in a direction opposite to the projection direction (on the back side of diaphragm 70 shown in FIG. 1A). By forming the partition walls (ribs) a11 to a47, respectively, the rigidity in the direction orthogonal to the longitudinal direction of the protrusions (tops) 7a1 to 7a7 (the left-right direction shown in FIG. 1A) is enhanced. And an electroacoustic transducer.

(2) In the electro-acoustic transducer according to the above (1), the partition walls (ribs) a11 to a47 are arranged in a direction perpendicular to the longitudinal direction of the projections (tops) 7a1 to 7a7 (FIG. 1). (A), a plurality of electroacoustic transducers formed at predetermined intervals in the horizontal direction in FIG. 2 (A).

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electroacoustic transducer according to the present invention will be described with reference to the drawings. FIG. 1 is a view for explaining an embodiment of the electro-acoustic transducer of the present invention. FIG. 1A is a front view of the electro-acoustic transducer, and FIG. FIG. 2 is a cross-sectional view for explaining the diaphragm constituting the electroacoustic transducer of the present invention. FIG. 2A is a front view of the diaphragm, and FIGS. FIG. 5 is a vertical cross-sectional view of the diaphragm taken along line AA ′ and line BB ′. The same components as those described above are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIGS. 1 and 2, the electro-acoustic transducer (entirely driven thin speaker unit) AA of the present invention further increases rigidity in a direction perpendicular to the longitudinal direction of each of the tops 7a1 to 7a7. In this case, a raised diaphragm 70 is used. Specifically, in contrast to the conventional one in which no member is provided inside (inside) each of the ridges 7a1 to 7a7, a direction inward and opposite to the projection direction (FIG. 1,
Ribs a11 to a47 are provided at regular intervals on the back side of the paper surface on which FIG. 2 is described, and each of the ribs a11 to a47 extends in a direction orthogonal to the longitudinal direction of each of the tops 7a1 to 7a7. The vibration plate 70 provided is used.

As shown in FIGS. 1A and 1B, a fully driven thin speaker unit AA, which is an electroacoustic transducer of the present invention, has a frame 1, a rear plate 2, a magnet 3,
The pole piece 4, the guide pin 5, the boil coil 6, the diaphragm (diaphragm) 70, the damper 8, and the edge 9 are roughly constituted.

The diaphragm (diaphragm) 70 is made of a polyimide (PI) film that withstands heat generated by the boil coil 6 and has excellent mechanical properties as a diaphragm, and is integrally molded. This diaphragm 70 is, as described above,
The magnet 3 is fixed on the rear plate 2 and the pole piece 4, and the periphery thereof is positioned and fixed to the frame 1 by an edge 9 made of urethane or the like.

The vibration plate 70 is, as shown in FIGS.
Plural tops 7a1 to 7a7, flat portion 7b, outer peripheral portion 7c
Consists of In order to increase the rigidity of each of the top portions 7a1 to 7a7, ribs a11 to a47 are provided inside the respective top portions 7a1 to 7a7. That is, the top 7a1 has four ribs a11 to a41, and similarly, the top 7a2 has four ribs a12 to a42, the top 7a3 has four ribs a13 to a43, and the top 7a4 has four.
The four ribs a14 to a44 and the top 7a5
15 to a45, the top 7a6 has four ribs a16 to a4
6. The top 7a7 has four ribs a17 to a47, respectively. These ribs a11 to a47 are
Needless to say, it is formed at the time of integral molding of 0. The thickness of the ribs a11 to a47 is the same as the thickness (75 μm) of the tops 7a1 to 7a7.

FIG. 2B shows a rib a
Tops 7a1-7a7 not provided with 11-a47
Is a vertical cross-sectional view. On the other hand, FIG. 4C shows a top portion 7 having ribs a31 to a37 provided inside.
It is a longitudinal cross-sectional view of a1-7a7.

The ribs a31 to a37 (rib a11)
-A47) do not touch the flat portion 7b as shown in FIG. 3C, but in order to obtain the required rigidity,
This may be molded so that the tip portion contacts the flat portion 7b. Also, four ribs are formed per top (for example, the top 7a1 has four ribs a).
However, it is not necessary to limit to this number, and the number may be further increased in order to obtain the required rigidity.

Further, the thicknesses of the ribs a11 to a47 are all the same, but need not be limited to these, and in order to obtain the required rigidity, the thickness of the ribs provided near both ends of the tops 7a1 to 7a7 is required. The thickness may be smaller than the thickness of the rib provided at the center of the tops 7a1 to 7a7. For example, ribs a11 and a41 near both ends of the top 7a1
May be thinner than the thickness of the ribs a21 and a31 at the center. Furthermore, these ribs a11 to a
47 are provided on all the tops 7a1 to 7a7, respectively, in order to increase the rigidity of the top near the center of the main vibrating part 7A on which these tops 7a1 to 7a7 are mounted, more than the rigidity of the surrounding tops. Alternatively, a rib may be provided only on the top near the center. For example, the ribs a13 to a43, a are provided only on the top portions 7a3 to 7a5 near the center of the main vibrating portion 7A.
14 to a44 and a15 to a45 may be provided respectively.

Thus, the top portions 7a1-7 of the diaphragm 70
By forming a plurality of ribs a11 to a47 inside a7, the rigidity of the ridges 7a1 to 7a7 is increased, so that an audio signal (drive current) ), Unnecessary resonance (split vibration) in the main vibrating portion 7A, which occurs when the main vibrating portion 7A on which the top portions 7a1 to 7a7 are mounted uniformly vibrates front and back uniformly over the paper surface. Generation can be reduced and acoustic distortion can be suppressed.

[0027]

According to the electroacoustic transducer of the present invention having the above-described structure, in particular, the projection is formed by forming a plurality of partitions inside the plurality of projections of the diaphragm and in a direction opposite to the projection direction. By increasing the rigidity in the direction perpendicular to the longitudinal direction of the part, the generation of unnecessary resonance (split vibration) in the main vibrating part is reduced and the acoustic distortion is suppressed even if the protruding part is vibrated integrally. An acoustic transducer can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining one embodiment of an electroacoustic transducer of the present invention.

FIG. 2 is a diagram for explaining a diaphragm constituting the electro-acoustic transducer of the present invention.

FIG. 3 is a diagram for explaining a conventional electroacoustic transducer.

FIG. 4 is a diagram illustrating a diaphragm constituting a conventional electroacoustic transducer.

[Explanation of symbols]

7, 70 diaphragm 7a1 to 7a7 top (projection) a11 to a47 rib (partition) A, AA full-surface drive thin speaker unit (electroacoustic transducer)

Claims (2)

[Claims] 1. An electroacoustic transducer comprising a planar diaphragm in which a plurality of elongated protrusions are formed in parallel, wherein the electroacoustic transducer is located inside the protrusion and in a direction opposite to the direction of the protrusion. An electro-acoustic transducer characterized in that rigidity in a direction perpendicular to a longitudinal direction of the projection is increased by forming partition walls on each of the projections. 2. The electroacoustic transducer according to claim 1, wherein the partition wall is arranged in a direction orthogonal to a longitudinal direction of the projection.
An electroacoustic transducer, wherein a plurality of electroacoustic transducers are formed at predetermined intervals.