JP2010062819A - Speaker device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speaker device capable of preventing the degradation of sound quality and improving sound pressure characteristics in not only a low pitch band but also in middle and high pitch bands. <P>SOLUTION: The speaker device includes: a housing 2; a piezoelectric film diaphragm 3 having flexibility to be attached to the housing 2 so as to form an acoustic cavity 20 between it and the housing 2; and a speaker unit 4 having a diaphragm 21 to be attached to the housing 2. It is characterized in that the speaker unit 4 is attached to the housing 2, and the diaphragm 21 of the speaker unit 4 and the piezoelectric film diaphragm 3 are simultaneously vibrated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a speaker device.

  In recent years, with the miniaturization and thinning of stereo devices and television devices, there has been a demand for miniaturization and thinning of speaker devices serving as audio output devices.

  Patent Document 1 discloses a speaker device in which electrodes are formed on both front and back surfaces of a flexible piezoelectric film serving as a diaphragm, and the back side of the piezoelectric film is supported by an elastic support.

JP 2003-244791 A (abstract)

  The speaker device that employs a piezoelectric film as a diaphragm disclosed in the above-mentioned Patent Document 1 is excellent in reproduction capability in the mid-high range, but is insufficient as reproduction capability in the low range.

  In particular, this speaker device has an open back configuration without a back cavity in order to reduce the thickness of the device. For this reason, this piezoelectric speaker will be in the state which obtains a sound pressure with the synthetic sound of the sound radiated | emitted to the front side of a piezoelectric film, and the sound radiated | emitted to the back side. Therefore, there is a cancellation phenomenon in which the sound radiated from the front side of the piezoelectric film goes around to the back side of the piezoelectric film and cancels out with the sound radiated to the back side that is in the opposite phase to the sound on the front side. appear. In addition, the sound that wraps around the back side of the piezoelectric film may resonate with the sound that is radiated to the back side. In this case, the sound pressure increases rapidly, and as a result, so-called peaky sound is generated. There is also a problem that occurs.

  In particular, regarding the cancellation phenomenon described above, since the back of the piezoelectric film tends to occur on the low frequency band side where the frequency is low, the reproduction capability in the low frequency band of the speaker device is further reduced. Further, this cancellation phenomenon may cause a peak and a dip in the reproduction frequency band in relation to the phase characteristic, and in this case, there is a problem that the reproduction ability is impaired without becoming a flat characteristic.

  Furthermore, since this speaker device has an open back configuration, the sound obtained by the speaker device is composed of the sound radiated to the front side and the back side of the piezoelectric film and the reflected sound thereof. Since it is a synthesized sound, it is easy to obtain sound pressure, but there is also a problem that distortion sound is likely to occur.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a speaker device that can prevent deterioration in sound quality and improve acoustic characteristics not only in the low frequency band but also in the middle and high frequencies. Is to provide.

  In order to solve the above-described problems, the present invention provides a flexible piezoelectric film diaphragm that is attached to a housing and attached to the housing so as to form an acoustic cavity between the housing and the housing. A speaker unit having a diaphragm, and the speaker unit is mounted on a housing, and the diaphragm of the speaker unit and the piezoelectric film diaphragm are vibrated simultaneously.

  In another invention, in addition to the above-described invention, the piezoelectric film diaphragm is provided in a cylindrical shape.

  Furthermore, in another invention, in addition to the above-described invention, a reflector is mounted on the diaphragm of the speaker unit.

  Furthermore, in addition to the above-described invention, in another aspect of the invention, the casing is disposed below the piezoelectric film diaphragm, and a top plate having a substantially disk shape disposed above the piezoelectric film diaphragm. A lower cup having a cup shape to which the speaker unit is mounted, the top plate and the lower cup are connected, and a columnar support disposed inside the piezoelectric film diaphragm, and the top plate and the lower cup are connected. And a piezoelectric film connecting member for holding the piezoelectric film diaphragm.

  According to the present invention, deterioration in sound quality can be prevented, and sound pressure characteristics not only in the low sound band but also in the middle and high sound areas can be improved.

  Hereinafter, a speaker device 1 according to an embodiment of the present invention will be described with reference to the drawings. In the following description, in FIG. 1 to FIG. 3, the side where the top plate 5 exists is defined as “upper”, and the side where the speaker 4 is present is defined as “lower”.

  1 and 2 are perspective views of a speaker device 1 according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the speaker device 1 according to the embodiment of the present invention. FIG. 3 is a side sectional view of the speaker device 1 according to the embodiment of the present invention.

  As shown in FIGS. 1 and 2, the speaker device 1 is a hybrid that generates sound by simultaneously driving a piezoelectric film diaphragm 3 having a substantially cylindrical shape in its outer shape and a speaker 4 serving as a speaker unit. Type speaker device.

  As shown in FIG. 2, the speaker device 1 includes a housing 2, a piezoelectric film diaphragm 3 having a cylindrical shape attached to the housing 2, and a speaker 4 attached to the lower side of the housing 2. Consists mainly of. The housing 2 includes a top plate 5 disposed above the piezoelectric film diaphragm 3, a lower cup 6 disposed below the piezoelectric film diaphragm 3, and a piezoelectric film for holding the piezoelectric film diaphragm 3. It mainly has a connecting plate 10. In the present embodiment, a substantially columnar column 7 is disposed inside the piezoelectric film diaphragm 3, and a reflection foot 11 serving as a reflection plate is disposed below the speaker 4.

  As shown in FIG. 2, the piezoelectric film diaphragm 3 is configured by rolling a piezoelectric film having a rectangular shape with a width of 210 mm, a height of 297 mm, and a thickness of 80 μm into a cylindrical shape, for example. As a material of this piezoelectric film, it is possible to employ vinylidene fluoride resin (PVDF), and a conductive polymer is coated on both front and back surfaces. Further, a silver paste (not shown) and a copper foil (not shown) are applied to the front and back surfaces of the coated piezoelectric film, respectively, and a pair of electrodes is formed by the silver paste and the copper foil. The material of the piezoelectric film is not limited to PVDF, and other materials such as a composite piezoelectric sheet in which a piezoelectric ceramic is mixed with a polymer sheet such as an epoxy resin may be employed. Moreover, as an electrode material, it is not limited to silver and copper, For example, it is possible to employ | adopt highly conductive metals, such as aluminum. Further, an input lead wire (not shown) is connected to the electrode described above.

  As shown in FIGS. 1 and 2, the top plate 5 has a disk-like form having substantially the same diameter as the piezoelectric film diaphragm 3 rolled into a cylindrical shape. The dimensions of the diameter and thickness of the top plate 5 are, for example, 67.6 mm and 10 mm, respectively. However, the dimensions of the top plate 5 can be appropriately changed according to the diameter of the piezoelectric film diaphragm 3. In the center of the top plate 5, as shown in FIG. 3, a screw hole 5 a having a diameter of 4.2 mm provided with a counterbore for a screw head having dimensions of a diameter and a depth of, for example, 8 mm and 4.5 mm, respectively. Is provided. Further, a stepped portion 5c having a width of 8 mm and a depth of 0.3 mm is formed on the outer peripheral portion of the top plate 5, for example. In addition, aluminum is employ | adopted as a material of the top plate 5, The black alumite process is given to the surface. However, the material of the top plate 5 is not limited to aluminum. Further, the surface may not be anodized.

  As shown in FIGS. 1 to 3, the lower cup 6 has a cup-like configuration having an opening 6 a (see FIG. 3) that opens downward. Moreover, the cross-sectional shape of the lower cup 6 has a substantially trapezoidal shape. The height of the substantially trapezoidal shape, the diameter of the lower end portion, and the diameter of the upper end portion are, for example, 50 mm, 84 mm, and 67 mm, respectively. The opening 6a has, for example, a cylindrical hole shape with a diameter of 58.2 mm and a height of 46 mm, and is formed on the lower side of the lower cup 6 by a hollowing process. Further, a total of four screw holes 6c are formed on the lower peripheral edge 6b of the lower cup 6 every 90 degrees in the circumferential direction.

  Further, as shown in FIG. 2, semi-circular holes 6 g and 6 g having a pair of semi-circular shapes that are symmetrical on the left and right are formed on the upper end portion of the lower cup 6. The semicircular holes 6g and 6g are formed, for example, with an interval of a width of 16 mm. The radius of the semicircular hole 6g is 29 mm. For this reason, the lower cup 6 is configured to have a central frame portion 6d that bridges the center of the upper end portion thereof. The width dimension of the frame portion 6d is, for example, 16 mm. The central frame portion 6d is provided with three countersunk holes 6e that can be screwed from below (see FIGS. 2 and 3). In the present embodiment, aluminum is adopted as the material of the lower cup 6, and the surface thereof is subjected to black alumite treatment. Note that the material of the lower cup 6 is not limited to aluminum.

  As shown in FIGS. 2 and 3, the top plate 5 and the lower cup 6 are connected by a support column 7 and a piezoelectric film connecting plate 10. The column 7 has, for example, a cylindrical shape with a diameter of 10 mm and a length of 269 mm. For example, screw holes 7 a having a diameter of 4 mm are formed on the upper end surface and the lower end surface of the support column 7. Aluminum is adopted as the material of the support column 7. However, the material of the column 7 is not limited to aluminum. The top plate 5 and the support column 7 are fixed by screwing screws 12 from above the top plate 5 into the screw holes 5 a and the upper screw holes 7 a of the support columns 7. The lower cup 6 and the column 7 are fixed by screwing screws 13 into the countersunk hole 6e provided at the center of the central frame 6d and the screw hole 7a below the column 7 from the back side of the central frame 6d. The

  Further, the piezoelectric film connecting plate 10 is disposed between the top plate 5 and the lower cup 6 so as to be adjacent to the support column 7. The piezoelectric film connecting plate 10 includes a vertically long plate portion 10a and a flange portion 10b extending so as to face the lateral direction from both ends in the vertical direction. The length of the long plate portion 10a in the longitudinal direction is the same as that of the support column 7 (for example, 269 mm), and the width and thickness are, for example, 28 mm and 6 mm, respectively. Further, the outer peripheral surface 10c of the long plate portion 10a is formed in a curved shape such that the radius of curvature is, for example, an arc of 33.5 mm as seen from above so as to coincide with the outer shapes of the top plate 5 and the lower cup 6. Has been.

  The flange portion 10b has a rectangular shape, and the width, length, and thickness thereof are, for example, 14 mm, 20 mm, and 4 mm, respectively. Each flange portion 10b is provided with two holes 10d having a diameter of 3.2 mm, for example. The hole 10d provided in the lower flange portion 10b is provided so as to correspond to the two countersunk holes 6e on the outside (other than the center) provided in the central frame portion 6d. Further, as shown in FIG. 3, two back screw holes 5b are provided on the back side of the top plate 5 so as to correspond to the holes 10d provided in the upper flange portion 10b. The piezoelectric film connecting plate 10 is fixed to the top plate 5 by screwing screws 14 into the holes 10d and the back screw holes 5b provided in the top plate 5 from the back side of the upper flange portion 10b. Further, the piezoelectric film connecting plate 10 is attached to the lower cup 6 by screwing screws 14 into the two outer countersunk holes 6e provided in the hole 10d and the center frame part 6d from the front side of the lower flange part 10b. Fixed. In this embodiment, the piezoelectric film connecting plate 10 is disposed so as to be adjacent to the support column 7. However, the support column 7 may be configured integrally with the piezoelectric film connecting plate 10. In other words, by providing the piezoelectric film connecting plate 10 with the same role as the support 7, it is possible to adopt a configuration in which the support 7 is omitted.

  The piezoelectric film diaphragm 3 is attached to the side of the housing 2 so as to cover the outside of the support column 7 assembled as described above. The piezoelectric film diaphragm 3 is provided with an adhesive sheet (not shown) on the stepped portion 5c provided on the outer peripheral portion of the top plate 5, the outer peripheral portion at the upper end of the lower cup 6, and the outer peripheral surface 10c of the long plate portion 10a in the piezoelectric film connecting plate 10. It is fixed using. Specifically, the adhesive sheet is attached to the stepped portion 5c, the outer peripheral portion, and the outer peripheral surface 10c described above, and each end portion of the piezoelectric film diaphragm 3 is pressed against the adhesive sheet to be attached to the housing 2. Thereby, the piezoelectric film diaphragm 3 is fixed to the housing 2 as a substantially cylindrical shape having a diameter of about 68 mm and a length of 269 mm, for example, with the support column 7 as the center. As a result, an acoustic cavity 20 having a substantially ring shape as viewed from above is formed in the space between the support column 7 and the piezoelectric film diaphragm 3 (see FIG. 3).

  Further, as shown in FIGS. 1 to 3, the speaker 4 is mounted below the lower cup 6. The speaker 4 is a moving coil type speaker, and includes a cone-shaped diaphragm 21, a voice coil 22 constituting a part of a driving body attached to the center of the diaphragm 21, and a magnetism constituting a part of the driving body. The circuit 23 is mainly included. The diameter of the outer edge portion of the diaphragm 21 is about 46 mm, for example, and the suspension 24 is provided on the outside thereof. The diameter of the suspension 24 is about 50 mm, for example. Moreover, the diameter of the voice coil 22 is about 19.5 mm, for example, and, for example, an 8Ω type is adopted. The voice coil 22 is mounted on a substantially cylindrical voice coil bobbin 25.

  The magnetic circuit 23 includes a yoke 26 and a magnet 27 serving as a magnetism generating unit. The yoke 26 includes a bottom yoke 26a and a holding yoke 26b. The bottom yoke 26a is formed so that a cylindrical column part 26d protrudes downward in FIG. 3 from the center of the bottomed disk-shaped disk part. A screw hole 26e is provided in the center of the bottom yoke 26a so as to penetrate the bottom yoke 26a. The ring-shaped magnet 27 is inserted into the cylindrical portion 26d, and the magnet 27 is locked to the bottom yoke 26a by inserting the holding yoke 26b into the cylindrical portion 26d of the bottom yoke 26a from below. The voice coil 22 is disposed in a gap formed between the inner peripheral surface of the holding yoke 26b and the outer peripheral surface of the cylindrical portion 26d. As the magnet 27, a magnet having an outer diameter and an inner diameter of, for example, 50 mm and 22 mm, respectively, and a magnetic flux density of, for example, 8 t is used. Further, in the present embodiment, since parts such as a dust cap and a chamber are not mounted, the vicinity of the tip portion of the cylindrical portion 26d is exposed to a part inside the voice coil bobbin 25.

  An iron frame 28 is attached to the outside of the voice coil bobbin 25. The frame 28 has a flange portion 28a, and its maximum external dimension is, for example, 82 mm. The flange portion 28a has a total of four holes 28c at intervals of 90 degrees in the circumferential direction from the center of the frame 28 so as to correspond to the screw holes 6c of the lower cup 6, for example, at a position having a distance of 72 mm. Is provided. The diameter of the hole 28c is 6 mm, for example. Then, the speaker 4 is disposed inside the opening 6a of the lower cup 6 so that the flange portion 28a contacts the lower edge 6b of the lower cup 6, and the screw 30 is screwed into the hole 28c and the screw hole 6c. Thus, the speaker 4 is fixed in the lower cup 6.

  Further, as shown in FIGS. 1 to 3, a reflective foot 11 is attached below the speaker 4. The reflection foot 11 plays the role of reflecting the sound radiated from the speaker 4 by the substantially conical slope 11e and diffusing it in all angular directions. The reflective foot 11 is not an essential configuration, and may be configured such that the reflective foot 11 is not attached to the speaker 4. The reflection foot 11 has a substantially triangular pyramid-shaped conical portion 11a and a substantially columnar columnar portion 11b that protrudes upward from the top. A hollow portion 11c hollowed out in a substantially triangular pyramid shape is formed on the back side of the conical portion 11a, and a circular hole 11d is formed so as to penetrate the columnar portion 11b upward from the hollow portion 11c. . The reflective foot 11 is inserted into the voice coil bobbin 25 with the columnar portion 11b, and the screw 32 is screwed into the circular hole 11d and the screw hole 26e of the bottom yoke 26a from the back side of the reflective foot 11 with respect to the speaker 4. Fixed. The maximum outer diameter of the cone portion 11a and the height dimension of the cone portion 11a are, for example, 86 mm and 20 mm, respectively. In addition, the diameter and height of the columnar part 11b are set to 17 mm and 22 mm, respectively, for example. The diameter of the circular hole 11d is 4.2 mm. Furthermore, the curvature radius in the cross section of the inclined surface 11e of the cone-shaped part 11a shown in FIG. 3 is about 39 mm, for example. This reflective foot 11 is formed by cutting aluminum.

  In the speaker device 1 configured as described above, the acoustic cavity 20 is configured using the piezoelectric film diaphragm 3, and the speaker 4 is attached to the housing 2, thereby providing the piezoelectric film diaphragm 3 and the speaker 4. It is possible to simultaneously generate sound by vibrating the diaphragms 21 that are provided. Therefore, it is possible to reproduce sound in a wide sound range that cannot be realized by a conventional speaker device using a piezoelectric film (hereinafter referred to as a piezoelectric film speaker), and the performance of the speaker device 1 can be improved.

  In the speaker device 1, since the piezoelectric film diaphragm 3 and the speaker 4 are used in combination, it is possible to reproduce sound in a low frequency range that is difficult to obtain with a conventional piezoelectric film speaker. Therefore, the sound pressure in the reproduction band (low sound range) that is difficult to obtain with the piezoelectric film speaker is supplemented by the speaker 4, and sufficient sound pressure can be obtained in the low sound range in addition to the sound pressure in the middle and high sound range. Become.

  In the speaker device 1, the acoustic cavity 20 is formed on the back side, and the back side is not opened. For this reason, the sound radiated from the piezoelectric film diaphragm 3 and the speaker 4 wraps around the back side of the piezoelectric film diaphragm 3, cancels out the opposite phase sound generated on the back side of the piezoelectric film diaphragm 3, and decreases the sound pressure. It is possible to prevent the so-called cancellation phenomenon from occurring. In addition, the above-mentioned sound that wraps around resonates with the sound generated on the back side of the piezoelectric film diaphragm 3, so that it is possible to prevent a sudden increase in sound pressure.

  In the speaker device 1, the acoustic cavity 20 is formed on the back side, so that the sound obtained from the piezoelectric film diaphragm 3 is sound radiated to the front side with respect to the piezoelectric film diaphragm 3. For this reason, it can prevent that the sound radiated | emitted to this front side is synthesize | combined with the sound radiated | emitted to the back surface side of the piezoelectric film diaphragm 3, and those reflected sounds, and a synthetic | combination sound is formed. Therefore, it is possible to obtain better sound quality than the conventional piezoelectric film speaker. As a result, the performance of the audio system can be improved.

  In the speaker device 1, the piezoelectric film diaphragm 3 has a substantially cylindrical shape. Therefore, as compared with the conventional moving coil type speaker device, an omnidirectional speaker can be obtained very easily without using a complicated configuration. Further, since the piezoelectric film diaphragm 3 uses a flexible piezoelectric film, it can be easily formed into a cylindrical shape and a sealed space can be easily formed. Therefore, it is possible to easily and reliably obtain an omnidirectional sound.

(Experiment 1)
4A and 4B are diagrams showing characteristics of sound radiated from the speaker device 1 according to the embodiment of the present invention. FIG. 4A is a diagram showing directivity characteristics, and FIG. (C) is a diagram showing frequency characteristics of the piezoelectric film diaphragm 3, the speaker 4 serving as a speaker unit, and the speaker device 1. FIG. In the measurement of the frequency characteristics of the sound radiated from the speaker device 1, the input signal is the same, but the impedance of the piezoelectric film diaphragm 3 and the speaker 4 is significantly different. An amplifier for driving the diaphragm 3 and an amplifier for driving the speaker 4 were prepared separately.

  As shown in FIG. 4A, in the directivity characteristics at each frequency, a graph composed of substantially concentric gains was obtained. Therefore, it was found that the sound of each frequency radiated from the speaker device 1 has no directivity. Further, as shown in FIG. 4B, it can be seen that the frequency characteristics of the sound radiated from the piezoelectric film diaphragm 3 and emitted in each direction (angle) are substantially the same. It was. For this reason, it turned out that the sound of the mid-high range radiated | emitted from the piezoelectric film diaphragm 3 also has no directivity. In addition, from FIG. 4C, by using the piezoelectric film diaphragm 3 and the speaker 4 together, a result in which the frequency characteristics are substantially flat was obtained. Therefore, if the piezoelectric film diaphragm 3 and the speaker 4 are used in combination, the speaker 4 can supplement the low-frequency sound pressure that is generally difficult to obtain with the piezoelectric film speaker. It was found that the sound acquired at both the front and rear positions has a sound pressure above a certain level.

  From the above results, by providing the acoustic cavity 20 on the back side of the speaker device 1, the sound radiated from the piezoelectric film diaphragm 3 and the speaker 4 does not wrap around the back side of the piezoelectric film diaphragm 3, and the cancellation phenomenon It was also found that the generation of resonance sound can be prevented and the sound quality can be improved. Further, in the speaker device 1, by attaching the reflective foot 11 to the speaker 4, the sound emitted from the speaker 4 can be reflected in all angular directions, and directivity can be eliminated in the low frequency band. Furthermore, it has been found that in the high sound band, it is possible to obtain omnidirectional sound that is difficult to obtain with a conventional piezoelectric film speaker. Therefore, it was found that the speaker device 1 can obtain a sound pressure of a certain level or higher regardless of the angle in all frequency bands.

(Experiment 2)
FIG. 5 is a diagram showing characteristics of sound radiated from a conventional moving coil type speaker, (A) is a diagram showing directivity characteristics, and (B) is a moving coil type for each direction (angle). It is a figure which shows the frequency characteristic of the sound radiated | emitted from a speaker. In the measurement of the frequency characteristics of the sound radiated from the moving coil type speaker, a speaker system consisting of 2 WAY of a square cabinet was used.

  As shown in FIG. 5 (A), the directivity graph composed of gains at each frequency is eccentric to the front so that the sound pressure in the front (0 ° side) increases, and has a substantially egg shape. . Further, as shown in FIG. 5B, it was found that the sound pressure in the high frequency band decreases as the viewing angle increases (away from 0 °). From the above results, it has been found that the characteristics of the sound radiated from the conventional moving coil type speaker have such characteristics that the sound pressure decreases as the viewing angle with respect to the speaker increases.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be implemented in various modifications.

  In the above-described embodiment, the acoustic cavity 20 composed of one space is formed by the piezoelectric film diaphragm 3, the top plate 5, and the lower cup 6. For example, a plurality of acoustic cavities are provided by providing a partition in the lower cup 6 or the like. May be formed to make the function of the cavity independent. Further, the above-described partition wall may be appropriately provided with a hole, a port, or the like according to the purpose, and the acoustic cavity may be used effectively. Furthermore, you may change suitably the shapes of the top plate 5, the lower cup 6, etc. according to the objective.

  In the above-described embodiment, the acoustic cavity 20 is composed of the piezoelectric film diaphragm 3, the top plate 5 and the lower cup 6. However, the acoustic cavity 20 is composed of the piezoelectric film diaphragm 3, the top plate 5 and the lower cup 6. For example, the acoustic cavity 20 may be composed only of the piezoelectric film diaphragm 3.

  Moreover, in the above-mentioned embodiment, although the form of the speaker apparatus 1 has a substantially cylindrical form, the form of the speaker apparatus 1 is not limited to a substantially cylindrical form. Other forms such as a prismatic shape or a conical shape may be used.

  Moreover, in the above-mentioned embodiment, although the reflective foot 11 is comprised with aluminum, the material of the reflective foot 11 is not limited to aluminum, For example, also as other materials, such as resin and wood good.

  In the above-described embodiment, the piezoelectric film diaphragm 3 is fixed to the casing 2 using an adhesive sheet. However, the method for attaching the piezoelectric film diaphragm 3 to the casing 2 uses an adhesive sheet. For example, it may be fixed by a rubber band or bonded by an adhesive.

  In the above-described embodiment, the side of the support column 7 is surrounded by the piezoelectric film diaphragm 3. However, only a part of the side of the support column 7 is surrounded by the piezoelectric film diaphragm 3, and the other part is the other. You may make it comprise from this member.

  Further, a piezoelectric film diaphragm 3 and a top plate 5 may be further provided on the top plate 5 of FIG. 1 to form a plurality of acoustic cavities such as a second acoustic cavity. At this time, each piezoelectric film diaphragm 3 can be made to correspond to each sound range by performing dimension adjustment or the like. Moreover, it is good also as a structure which arrange | positions the speaker apparatus 1 upside down so that the top plate 5 may become a lower side.

  The speaker device of the present invention can be used in an acoustic conversion device such as a speaker that emits sound from a diaphragm.

1 is a perspective view of a speaker device according to an embodiment of the present invention. It is a disassembled perspective view of the speaker apparatus which concerns on one embodiment of this invention. It is side sectional drawing of the speaker apparatus which concerns on one embodiment of this invention. It is a figure which shows the characteristic of the sound radiated | emitted from the speaker apparatus based on one embodiment of this invention, (A) is a figure which shows directional characteristics, (B) is a piezoelectric film with respect to each direction (angle) It is a figure which shows the frequency characteristic of a diaphragm, (C) is a figure which shows the frequency characteristic of a piezoelectric film diaphragm, a speaker unit, and a speaker apparatus. It is a figure which shows the characteristic of the sound radiated | emitted from the conventional moving coil type | mold speaker, (A) is a figure which shows a directional characteristic, (B) is radiated | emitted from the moving coil type | mold speaker with respect to each direction (angle). It is a figure which shows the frequency characteristic of a sound.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Speaker apparatus 2 ... Housing 3 ... Piezoelectric film diaphragm 4 ... Speaker (speaker unit)
5 ... top plate 6 ... lower cup 7 ... support 10 ... piezoelectric film connecting plate (piezoelectric film connecting member)
11 ... Reflective feet (reflector)
21 ... diaphragm 20 ... acoustic cavity

Claims (4)

A housing,
A flexible piezoelectric film diaphragm attached to the housing so as to form an acoustic cavity with the housing;
A speaker unit having a diaphragm attached to the housing;
With
A speaker device, wherein the speaker unit is mounted on the housing, and the diaphragm of the speaker unit and the piezoelectric film diaphragm are vibrated simultaneously.   The speaker device according to claim 1, wherein the piezoelectric film diaphragm is provided in a cylindrical shape.   The speaker device according to claim 1, wherein a reflector is attached to the diaphragm of the speaker unit. The housing is
A top plate having a substantially disk-like shape disposed above the piezoelectric film diaphragm;
A lower cup that is disposed below the piezoelectric film diaphragm and has a cup-like shape to which the speaker unit is attached;
A columnar column that connects the top plate and the lower cup and is disposed inside the piezoelectric film diaphragm;
A piezoelectric film connecting member arranged to connect the top plate and the lower cup, and holding the piezoelectric film diaphragm;
The speaker device according to claim 1, comprising:

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