JP2017069938A - Autonomous plane speaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an autonomous type plane speaker which is capable of securing desired sound quality and intensity by simply controlling the vibration of a diaphragm without providing a rib, can be used without limitation under various environments including a hostile environment of high temperature and humidity, and is easy to install durably.SOLUTION: An autonomous type plane speaker 1 according to this invention comprises: a generally plane diaphragm 2 made of fiber-reinforced plastic; and a vibration generation device 20 attached to the diaphragm 2. The diaphragm 2 comprises: a placed part 2b which is placed on an installation surface 50 on which the diaphragm 2 is to be installed; a body 2a which stands upward from the placed part 2b, forming a predetermined angle with respect to the placed part 2b; and a bent part 30 which is bent and formed from the body 2a and controls the attenuation factor of vibration propagating the diaphragm 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flat speaker, and more particularly to a self-supporting flat speaker that can stand by itself on an installation surface.

  Conventionally, various types of flat speakers in which a vibration generator is attached to a flat diaphragm have been known (see, for example, Patent Document 1 and Patent Document 2). In such a flat speaker, for example, an audio signal input from the outside and converted into a weak current is amplified by an amplifier and sent to a vibration generator. Then, sound is generated by applying vibration generated by the vibration generator to the diaphragm based on the current.

  Further, the vibration generator includes, for example, a magnet and a coil provided opposite to the magnet, and a current (external input weak current described above) is passed through the coil in a direction orthogonal to the magnetic field generated by the magnet. By generating a force according to Fleming's left-hand rule between the magnetic field and the magnetic field, for example, by vibrating the vibrating rod, the vibrating rod is brought into contact with the vibrating plate to vibrate the vibrating plate (thus vibrating the electric signal). (Converted into (acoustic signal)).

  Also, in such a flat speaker, there is also known a structure in which ribs are installed on the diaphragm to control the vibration to adjust the sound quality (obtain a desired frequency characteristic) and reinforce the diaphragm (for example, And Patent Document 3).

International Publication No. 2003/073787 JP 2003-174694 A JP 2008-028812 A

  By the way, in the flat speaker, when the rib is attached to the diaphragm as disclosed in Patent Document 3, the rib is individually bonded using a vibration-absorbing adhesive so as not to inhibit the vibration of the diaphragm at the attachment portion. Therefore, special consideration is required, and the work at the time of manufacture becomes complicated. Further, when the rib is exposed on the outer surface of the speaker, the appearance may be deteriorated. Further, the rib is often provided on the back surface of the diaphragm. However, if the rib is provided on the back surface, the back surface of the diaphragm is bulky and the installation space for other speaker components such as a vibration generator is limited. .

  Also, loudspeakers that require a large volume are generally unsuitable for installation in environments where large spaces cannot be secured because they are large and require a large installation space, but you want to install a loud speaker that saves space. There are also needs. Also, in diversified acoustic environments as in recent years, it is desirable that speakers can be installed without restrictions even in harsh environments. However, in high temperature and high humidity environments, the durability of materials such as diaphragms may not be maintained. is there.

  Furthermore, in an audio facility used for promotion on a display or the like, an environment for supporting a flat speaker may not be prepared. In such a case, a speaker that can stand on the installation surface is required.

  The present invention has been made paying attention to the above-mentioned problems, and can easily control the vibration of the diaphragm without providing ribs to ensure desired sound quality and strength, and includes a severe environment of high temperature and high humidity. It is an object of the present invention to provide a self-supporting flat speaker that can be used almost without limitation in various environments and is easy to install with excellent durability.

  In order to achieve the above object, the self-supporting flat speaker of the present invention is attached to the substantially planar diaphragm formed of fiber reinforced plastic and the diaphragm, and converts an input electric signal into vibration. A vibration generating device that transmits the vibration to the diaphragm, the diaphragm being placed on an installation surface on which the diaphragm is to be installed, and a predetermined angle with respect to this from the placement part And a bending portion that is bent from the main body portion and controls the attenuation rate of vibration propagating through the diaphragm.

  According to the above configuration, since the attenuation rate of the vibration propagating through the diaphragm is controlled by the bent portion formed by bending from the main body, it is not necessary to attach a rib to the diaphragm as in the prior art. Therefore, the appearance is good, and the diaphragm is not bulky due to the presence of the ribs, and the degree of freedom of installation of other speaker components such as a vibration generator is ensured. In particular, since such a bent portion can be provided on the vibration plate (main body portion) by, for example, bending the vibration plate (main body portion) or by integral molding, it is easy to manufacture (vibration absorbing properties as in the past). This avoids complicated operations such as bonding the ribs individually using an adhesive). Further, such a bent portion also has a reinforcing effect for increasing the rigidity of the diaphragm.

  Moreover, according to the said structure, since a diaphragm has a mounting part, even when the environment which supports a planar speaker is not prepared, it can stand on the installation surface itself. Therefore, it can be freely moved and installed in any place (for example, on a flat place where there is nothing or even on a desk).

  In addition, according to the above configuration, the vibration plate can be simply selected by appropriately selecting the formation position of the bent portion with respect to the main body according to the use of the speaker, the required acoustic effect, or the size of the vibration plate. The desired sound quality and volume can be ensured by simply controlling the vibration (for example, by smoothing the amplitude of vibration throughout the diaphragm so that no peak of acoustic intensity occurs). Also, for example, if a vibration transmitting material is connected to the mounting part of the diaphragm (or if the mounting part is connected to the vibration transmitting material of the existing equipment), the vibration of the diaphragm is also transmitted to such a vibration transmitting material. Therefore, it is possible to achieve a larger volume even with a low output acoustic amplifier. In addition, since the diaphragm is made of fiber reinforced plastic, it is lightweight and easy to carry, has excellent durability, and can be used without limitation in various environments including severe environments of high temperature and high humidity.

  According to the present invention, it is possible to easily control the vibration of the diaphragm without providing a rib to ensure a desired sound quality and strength, and to be used almost without limitation in various environments including high-temperature and humid environments. A self-supporting flat speaker having excellent durability and easy installation can be obtained.

It is the schematic perspective view which looked at the self-supporting planar speaker which concerns on one Embodiment of this invention from the front. It is the schematic perspective view which looked at the self-supporting planar speaker of FIG. 1 from the side. It is a side view which shows the structure of the vibration generator attached to a diaphragm. It is an example of the prepreg sheet which forms the laminated structure of a diaphragm, (a) is a schematic plan view of the prepreg sheet which aligned the reinforcing fiber in the axial length direction, (b) is knitting the reinforcing fiber in the triaxial direction. It is a schematic plan view of a prepreg sheet. It is a schematic sectional drawing of an example of the laminated structure of a diaphragm. It is the schematic perspective view which looked at the metal mold | die for shape | molding the diaphragm of the self-supporting planar speaker of FIG. 1 from the back side. It is the schematic perspective view which looked at the metal mold | die for shape | molding the diaphragm of the self-supporting planar speaker of FIG. 1 from the side. It is a frequency characteristic graph which shows the experimental result in the predetermined time at the time of attaching the vibration generator which has the same frequency characteristic to the center position A shown by FIG. It is a frequency characteristic graph of the experimental data in the predetermined time at the time of attaching the vibration generator which has the same frequency characteristic to the upper position C shown by FIG. It is a frequency characteristic graph of the experimental data in the predetermined time at the time of attaching the vibration generator which has the same frequency characteristic to the lower position B shown by FIG. 2 is a frequency characteristic graph of experimental data at a predetermined time when a vibration generator having the same frequency characteristic is attached to the right position D or the left position E shown in FIG. 1. Frequency characteristics of experimental data at predetermined time points when the vibration generator is mounted at two locations, the center position A (high-frequency vibration generator) and the upper position C (low-frequency vibration generator) shown in FIG. It is a graph. It is an experimental result at the time of making the fiber which comprises a diaphragm in the vicinity of the spindle which is a connection part of a main-body part and a mounting part into low elasticity, Comprising: The vibration generator was attached to the center position A shown in FIG. It is a frequency characteristic graph of the experimental data at a predetermined time point in the case (the horizontal axis is frequency (Hz), the vertical axis is sound intensity (Pa)). It is an experimental result at the time of making the fiber which comprises a diaphragm in the vicinity of the spindle which is a connection part of a main-body part and a mounting part into low elasticity, Comprising: The vibration generator was attached to the center position A shown in FIG. It is a frequency characteristic graph of the experimental data at a predetermined time in the case (the horizontal axis is frequency (Hz), the vertical axis is decibel (dB)). FIG. 3 is an experimental result when the fibers constituting the diaphragm are made low elasticity in the vicinity of the support shaft, which is a connecting portion between the main body portion and the mounting portion, and vibrations are generated at the left and right positions D and E shown in FIG. It is a frequency characteristic graph of the experimental data at the predetermined time when the apparatus is attached (the horizontal axis represents frequency (Hz), and the vertical axis represents sound intensity (Pa)). FIG. 3 is an experimental result when the fibers constituting the diaphragm are made low elasticity in the vicinity of the support shaft, which is a connecting portion between the main body portion and the mounting portion, and vibrations are generated at the left and right positions D and E shown in FIG. It is a frequency characteristic graph of the experimental data at the predetermined time when the apparatus is attached (the horizontal axis represents frequency (Hz), and the vertical axis represents decibel (dB)). 1 is a frequency characteristic graph of experimental data at a predetermined time when a vibration generator excellent in bass characteristics is attached to the upper position C shown in FIG. The vertical axis is the sound intensity (Pa). 1 is a frequency characteristic graph of experimental data at a predetermined time when a vibration generator excellent in bass characteristics is attached to the upper position C shown in FIG. The unit of the vertical axis is decibel (dB). FIG. 1 is a graph of frequency characteristics of experimental data at a predetermined time when a vibration generator having excellent bass characteristics is attached to the upper position C shown in FIG. (The horizontal axis is frequency (Hz) and the vertical axis is decibel (dB)). FIG. 2 is a frequency characteristic graph of experimental data at a predetermined time when a vibration generator having excellent high-frequency characteristics is attached to a position close to the center position A of 20 mm from the position D shown in FIG. The axis is frequency (Hz), and the vertical axis is sound intensity (Pa). FIG. 2 is a frequency characteristic graph of experimental data at a predetermined time when a vibration generator having excellent high-frequency characteristics is attached to a position close to the center position A of 20 mm from the position D shown in FIG. The axis is frequency (Hz), and the unit of the vertical axis is decibel (dB). 1 is a frequency characteristic graph of experimental data at a predetermined time when a vibration generator having excellent high-frequency characteristics is attached to a position close to the center position A from the position D shown in FIG. It is a graph at the time of reproducing music (the horizontal axis is frequency (Hz) and the vertical axis is decibel (dB)). In the middle-rigid diaphragm, a vibration generator excellent in low sound characteristics is attached to the upper position C shown in FIG. 1, and a vibration generator excellent in high sound characteristics is attached to a position close to the center position A 20 mm from the position D. It is a frequency characteristic graph of the experimental data at a predetermined time (the horizontal axis represents frequency (Hz) and the vertical axis represents sound intensity (Pa)). In the middle-rigid diaphragm, a vibration generator excellent in low sound characteristics is attached to the upper position C shown in FIG. 1, and a vibration generator excellent in high sound characteristics is attached to a position close to the center position A 20 mm from the position D. It is a frequency characteristic graph of the experimental data at a predetermined time (the horizontal axis represents frequency (Hz), and the vertical axis represents decibel (dB)). In the middle-rigid diaphragm, a vibration generator excellent in low sound characteristics is attached to the upper position C shown in FIG. 1, and a vibration generator excellent in high sound characteristics is attached to a position close to the center position A 20 mm from the position D. It is a graph of frequency characteristics of experimental data at a predetermined time point when music is reproduced (frequency (Hz) on the horizontal axis and decibel (dB) on the vertical axis). 17A and 17B on a medium-rigid diaphragm, a predetermined sound when a low-frequency vibration generator is attached to the upper position C and a high-frequency vibration generator is attached to the positions E and D. It is a frequency characteristic graph of the experimental data at the time of. In the diaphragm having intermediate rigidity, vibration generators having excellent high sound characteristics are attached to a position close to 20 mm center position A from position D and a position close to 20 mm center position A from position E shown in FIG. 6 is a frequency characteristic graph of experimental data at a predetermined time when a vibration generator having excellent bass characteristics is attached.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in FIG. 1, a self-supporting flat speaker 1 according to an embodiment of the present invention is attached to and input to a substantially planar diaphragm 2 made of fiber-reinforced plastic and the diaphragm 2. And a vibration generator 20 that converts an electrical signal into vibration and transmits the vibration to the diaphragm 2. In addition, the diaphragm 2 is placed on the placement surface 50 on which the diaphragm 2 is to be placed, and the placement portion 2b forms a predetermined angle θ (for example, about 74 °) with respect to the placement portion 2b. The main body 2a rising upward, and the bent portion 30 that is bent from the main body 2a and controls the attenuation rate of vibration propagating through the diaphragm 2.

In particular, in the present embodiment, one vibration generator 20 is provided at the center position of the back surface 2aB of the main body 2a, and the bent portions 30 are provided on both side surfaces 14 and 14 of the main body 2a (the back surface of the main body 2a). 2aB side) (for example, at an angle of 40 ° with respect to the main surface of the main body 2a). However, the number of the vibration generators 20 and the bent portions 30 is not limited to these, and can be arbitrarily set according to the application.

In the self-standing flat speaker 1, for example, an audio signal input from outside and converted into a weak current is amplified by an amplifier (not shown) and sent to the vibration generator 20. Then, the vibration generated by the vibration generator 20 based on the current is applied to the diaphragm 2 to generate sound.

Hereinafter, individual components of the self-standing flat speaker 1 will be described in detail.
First, the main body 2a of the diaphragm 2 is placed on the support shaft (here, the lower end (lower surface) 12 of the main body 2a) that is a connecting portion with the mounting portion 2b at the time of vibration accompanying sound generation. It is formed so as to be able to swing elastically with respect to 2b. In the present embodiment, the main body 2a extends so as to rise from the end (end edge) of the placement portion 2b, but may rise from the center of the placement portion 2b. In short, it is only necessary that the main body portion 2a is supported in a state where it can be elastically swung with respect to the mounting portion 2b and is raised by the mounting portion 2b (it can be self-supporting itself).

Here, the main body 2a and the mounting portion 2b may be separable (the main body 2a and the mounting portion 2b may be detachably attached). In that case, the connection between the main body portion 2a and the placement portion 2b is performed in a form that does not inhibit the transmission of vibration. Further, the surface 2aA of the main body 2a may be formed as a smooth surface (for example, surface coating may be applied), and the back 2aB of the main body may be formed into a rough surface.

  Further, as described above, the diaphragm 2 is formed of fiber reinforced plastic (FRP) formed by reinforcing a matrix resin with fibers. Examples of the matrix resin include an epoxy resin and a polyester resin. In consideration of durability against environmental changes, an epoxy resin is more preferable than a polyester resin. Moreover, although carbon fiber is mentioned as a reinforced fiber, you may be another kind of fiber. In the present embodiment, the diaphragm 2 is formed in a rectangular shape having two parallel or non-parallel side surfaces 14 and 14 and two parallel upper and lower surfaces 11 and 12. It may be a flat plate of the shape.

The diaphragm 2 is formed in consideration of the frequency characteristics of the generated sound. For example, in the case of carbon fiber reinforcement, the diaphragm 2 preferably has a carbon fiber tensile modulus of 23.5 tf / mm ² or more and a resin content of less than 37%. The reinforcing fibers may be oriented in multiple directions that form an angle with respect to these directions including the vertical direction and the horizontal direction of the diaphragm 2. In particular, in this embodiment, the diaphragm 2 is formed by laminating a plurality of resin layers having different fiber directions. In that case, the number of stacked layers is desirably four or more.

Specifically, for example, as shown in FIG. 5, the diaphragm 2 is formed by laminating a plurality of fiber reinforced plastic layers having different orientation directions of reinforcing fibers, for example, over 14 to 15 layers. Is made. As an example, in this laminated structure, in order from the outside, the first layer 42 in which the reinforcing fibers are aligned in the longitudinal direction (0 °), and the second and third layers in which the reinforcing fibers are aligned obliquely (for example, ± 45 °). The layers 43 and 44, the fourth layer 45 in which the reinforcing fibers are aligned in the transverse direction (90 °), and the like are repeatedly stacked in multiple layers, whereby the reinforcing fibers are oriented in at least four directions.

Alternatively, as shown in FIG. 4, a prepreg sheet 20 in which reinforcing fibers are aligned in the longitudinal direction (0 °) and a prepreg sheet 22 knitted with the reinforcing fibers oriented in three axial directions (directed in the 90 ° direction). Further, the reinforcing fiber 22a, the reinforcing fiber 22b oriented in the + 45 ° direction, and the triaxial prepreg sheet 22) formed by weaving the reinforcing fiber 22c oriented in the −45 ° direction may be used. By using such a triaxial prepreg sheet 22, high rigidity and torsional strength can be efficiently ensured without greatly increasing the weight.

Thus, if the diaphragm 2 is formed by a laminated structure in which reinforcing fibers are oriented in at least four directions, a laminated form close to quasi-isotropy can be realized, good vibration characteristics can be secured, and vibration can be ensured. There is no itch in the direction of the transmission. The orientation direction of the reinforcing fiber, the type of reinforcing fiber, the resin impregnation amount, the wall thickness, and the like are appropriately selected according to the use and desired sound quality. Moreover, in order to prevent peeling of a prepreg sheet (fiber), the outer surface (the surface and the back surface of the diaphragm 2) of a laminated structure may be covered with the woven fabric 40 (refer FIG. 5).

In addition, the diaphragm 2 having such a bent portion 30 can be integrally formed using, for example, a mold 100 shown in FIGS. 6 and 7. In this case, the mold 100 is, for example, a mold main body that is in the form of the diaphragm 2 and includes the main body portion 2a, the mounting portion 2b, and the portions 202a, 202b, and 230 corresponding to the bent portion 30. The portion 202 is supported by the base frame portion 102, and the base frame portion 102 is reinforced by the reinforcing plate 105 and the rib 115 fastened to the base frame portion 102 by bolts 150. When the diaphragm 2 is formed using such a mold 100, for example, the above-described prepreg sheet constituting the diaphragm 2 is attached to the mold 100 in a laminated state, and in that state, the prepreg sheet is evacuated. Is adsorbed to the mold 100 and molded.

  Here, the vertical and horizontal dimensions of the diaphragm 2 are set to 800 mm × 420 mm, for example, in the case of a rectangle as in the present embodiment, and the thickness of the diaphragm 2 is preferably 1.5 mm or more. In the embodiment, it is set to 3 mm, for example. Note that the volume (volume of sound) is proportional to the area of the diaphragm 2, but if the area is increased by making at least a part of the diaphragm 2 a box shape using the bent portion 30, the overall length and width of the diaphragm 2 are increased. It is also possible to obtain a large volume without increasing the dimensions.

  In addition, when the diaphragm 2 is circular, the vibration generator 20 can be displaced from the center of the diaphragm 2 to create portions having various resonance frequencies with respect to the vibration generated from the vibration generator 20. . Therefore, by using the rectangular or elliptical diaphragm 2, it is possible to deal with vibration frequencies that are more varied.

  Further, since the edge of the fiber is exposed at the outer peripheral edge of the diaphragm 2 made of FRP, in order to prevent breakage or injury, at least the outer peripheral edge of the diaphragm 2 as shown in FIG. 3 and FIG. It is preferable to attach a protective member made of synthetic resin, rubber or the like to a part. In this case, the protection member is attached to the diaphragm 2 by fitting and / or adhesion.

  The above-described bent portion 30 formed by bending from the main body portion 2a of the diaphragm 2 is substantially an inverted triangle so that the width gradually increases upward from the connection portion (lower surface 12) between the main body portion 2a and the mounting portion 2b. It is formed into a shape. Specifically, the width dimension (length extending from the side surface 14 of the main body 2a toward the back surface 2aB) of the upper portion 30a of the bent portion 30 located on the upper surface 11 side of the main body 2a is the lower surface of the main body 2a. It is set larger than the width dimension of the lower portion 30b of the bent portion 30 located on the 12 side. For example, the width dimension of the uppermost end of the upper part 30a is set to 40 mm, and the width dimension of the lowermost part of the lower part 30b is set to 3 mm. The reason for setting such a width is that if the lower part of the bent part 30 is widened to have rigidity below, vibration (swing) of the main body part 2a is hindered.

Note that the dimensions of the bent portions 30 may all be the same or different, depending on the size of the diaphragm 2 and the amount of vibration attenuation, or the position of the diaphragm 2 where the bent portions 30 are provided. It is set appropriately according to That is, these bent portions control the attenuation rate of vibration propagating through the diaphragm 2 depending on the material and size thereof and / or the position of the diaphragm 2 where the bent portion 30 is provided. For example, the rigidity of the diaphragm 2 is increased by the presence of the bent portion 30, and the vibration of the diaphragm 2 is controlled by suppressing the bending of the diaphragm 2 to a desired degree. For example, a smooth sound without an echo is generated. realizable.

  As an example of controlling the vibration damping rate, it is possible to prevent a peak in the sound intensity from occurring at some predetermined frequencies, in other words, to smooth the vibration amplitude over the entire diaphragm 2. However, the control mode for controlling the vibration attenuation rate of the diaphragm 2 is not limited to this, and various acoustic control modes can be realized by the bent portion 30. For example, contrary to the previous control mode, a bent portion may be provided at a position where an echo is generated. Further, when the bent portion 30 is provided at a position close to the vibration generating device 20, the frequency becomes high (becomes high sound), while when the bent portion 30 is provided at a position far from the vibration generating device 20, the frequency is low. It becomes possible to select a position where the bent portion 30 is formed according to the required sound quality and volume, and to realize a desired acoustic state. In addition, although different from the damping rate control, for example, if a vibration transmitting material is connected to the mounting portion 2b of the diaphragm 2 (or the mounting portion 2b is connected to a vibration transmitting material (for example, a floor surface) of existing equipment. In other words, the vibration of the diaphragm 2 is also transmitted to such a vibration transmitting material, and a larger sound volume can be realized with a low output acoustic amplifier.

  The vibration generator 20 that generates vibrations and transmits the vibrations to the diaphragm 2 is attached to the center of the back surface 2aB of the main body 2a of the diaphragm 2 as described above. In particular, in this embodiment, the thickness is 0.5 mm. It is attached to the back surface 2aB of the main body 2a of the diaphragm 2 using an acrylic resin adhesive having an adhesive strength of 20 N / cm or more based on an acrylic foam of ˜2.5 mm. However, the vibration generator 20 may be attached to the surface 2aA of the main body 2a of the diaphragm 2 by an attaching means other than an adhesive.

The vibration generator 20 includes, for example, a magnet (not shown) and a coil (not shown) provided to face the magnet, and a current (in the direction perpendicular to the magnetic field generated by the magnet) ( The aforementioned external input weak current) is applied to generate a force in accordance with Fleming's left-hand rule between the coil and the magnetic field, for example, by vibrating the vibrating rod, the vibrating rod is brought into contact with the vibrating plate and vibrated. The plate is vibrated (thus converting electrical signals into vibrations (acoustic signals)).

  In this case, the generated sound range may be adjusted using the thickness and hardness of the above-described acrylic foam interposed between the vibrating rod and the diaphragm 2 as adjustment parameters. Lowering the hardness of the acrylic foam or increasing the thickness of the acrylic foam emphasizes the low frequency range, while increasing the thickness of the acrylic foam increases the high frequency range. By utilizing this fact and attaching the vibration generating device 20 that emphasizes various types of sound ranges to the diaphragm 2, the sound quality to be reproduced can be adjusted to a desired sound quality.

  Further, in order to prevent distortion sound from being produced in the reproduced sound quality, the lead wire 24 (see FIG. 3) connecting the above-described amplifier and the vibration generator 20 (not shown) should not be in direct contact with the diaphragm 2. There must be. Therefore, for example, the lead wire 24 may be fixed to the diaphragm 2 with an adhesive tape whose base material is urethane or acrylic foam having a thickness of 5 mm or more, or the vibration generator 20 as shown in FIG. The lead wire 24 may be placed on the synthetic resin foam 23 attached to the diaphragm 2 adjacent to the substrate.

  In addition, for the purpose of protecting the vibration generating device 20 and for the purpose of floating the lead wire 24, a cover body 25 that covers the left and right vibration generating devices 20 individually and correspondingly with the adjacent synthetic resin foam 23 from the outside is provided. You may attach to the diaphragm 2 (refer FIG. 3). In this case, the cover body 25 is attached to the diaphragm 2 using a double-sided tape using a foam material as a base material so that the cover body 25 does not resonate with the vibration of the diaphragm 2 to generate abnormal noise. It is done.

  As described above, according to the self-standing flat speaker 1 of the present embodiment, the attenuation rate of vibration propagating through the diaphragm 2 is controlled by the bent portion 30 formed by bending from the main body portion 2a. Thus, it is not necessary to attach ribs to the diaphragm 2 as in the prior art. Therefore, the appearance is good, and the diaphragm 2 is not bulky due to the presence of the ribs, so that the degree of freedom of installation of other speaker components such as the vibration generator 20 is greatly secured. In particular, such a bent portion 30 can be provided on the diaphragm 2 (main body portion 2a) by bending or integrally forming the diaphragm 2 (main body portion 2a), for example. In addition, it is possible to avoid complicated operations such as bonding the ribs individually using a vibration-absorbing adhesive. Further, such a bent portion 30 also has a reinforcing effect for increasing the rigidity of the diaphragm 2.

  Moreover, according to this embodiment, since the diaphragm 2 has the mounting portion 2b, the diaphragm 2 can stand on the installation surface 50 even when the environment for supporting the flat speaker is not prepared. Therefore, it can be freely moved and installed in any place (for example, on a flat place where there is nothing or even on a desk).

  Further, according to the present embodiment, according to the use of the speaker, the required acoustic effect, or the size of the diaphragm, only by appropriately selecting the formation position of the bent portion 30 with respect to the main body portion 2a, The desired sound quality and sound volume can be ensured by simply controlling the vibration of the diaphragm 2 (for example, by smoothing the amplitude of vibration over the entire diaphragm 2 so that no peak of acoustic intensity occurs). Further, for example, if a vibration transmitting material is connected to the mounting portion 2b of the diaphragm 2 (or if the mounting portion 2b is connected to a vibration transmitting material of an existing facility), the vibration of the diaphragm 2 is such a vibration transmission. It is also transmitted to the material and can be realized with a low output acoustic amplifier with a larger volume. In addition, since the diaphragm 2 is formed of fiber reinforced plastic, it is lightweight and easy to carry, has excellent durability, and can be used almost without limitation in various environments including severe environments of high temperature and high humidity.

  In addition, the self-standing flat speaker 1 described above changes the mounting position of the vibration generator 20 with respect to the diaphragm 2 (main body 2a) or configures the diaphragm 2 due to the characteristic configuration described above. It is possible to easily change the generated sound from a high range to a low range simply by changing the elastic modulus of the fiber of the fiber reinforced plastic.

  Specifically, regarding the mounting position of the vibration generating device 20, in the above-described embodiment, the vibration generating device 20 is mounted at the center of the back surface 2aB of the main body 2a of the diaphragm 2, and this central mounting position is shown in FIG. The center position A of the entire body 2a is set as described above, and in the above-described dimension setting, for example, a position that is 210 mm (= L1) vertically downward from the center position A is B, for example 210 mm vertically upward from the center position A ( = L2) A position away from C, center position A on the right side parallel to the placement part 2b, for example, a position away from the center position A by 150 mm (= L3) in the horizontal direction, D, and a left side from the center position A parallel to the placement part 2b. For example, assuming that a position separated by 150 mm (= L4) in the horizontal direction is E, when the vibration generator 20 is mounted at the upper position C, the vibration generator 20 having the same frequency characteristic is attached. Compared with the case where the vibration generator 20 is mounted centered on the device A, the generated sound moves to the low frequency side. On the other hand, when the vibration generator 20 is mounted centered on the lower position B, the vibration generator 20 having the same frequency characteristics is used. The generated sound moves to the high-frequency region side as compared with the case where the center is attached to the position A. On the other hand, at the left and right positions D and E, the generated sound does not move greatly to the high sound range or the low sound range with respect to the position A.

  Therefore, when the vibration generator 20 having excellent low frequency characteristics is attached to the position C and the vibration generator 20 having excellent high sound characteristics is attached to the position B, the respective frequency characteristics of the vibration generator 20 can be effectively utilized. . Therefore, when a plurality of vibration generators 20 having different frequency characteristics are used, for example, by selecting an attachment position corresponding to the frequency characteristics, the frequency characteristics can be utilized or supplemented. In addition, when a plurality of vibration generators 20 having the same frequency characteristics are used, a large sound can be produced when installed at positions D and E.

  Further, regarding the elastic modulus of the fiber of the fiber reinforced plastic constituting the diaphragm 2, for example, in the vicinity of the support shaft (lower end (lower surface) 12 of the main body portion 2 a) that is a connection portion between the main body portion 2 a and the mounting portion 2 b, for example When the fiber is made highly elastic in the vicinity of the position B (or the molding thickness of the main body 2a at this part is increased), the high sound characteristic of the generated sound becomes excellent. On the other hand, on the upper side of the main body 2a, for example, in the vicinity of the position C, the fiber has low elasticity (or the amount of resin (epoxy resin or the like) contained in the laminated structure of the main body 2a at this portion is increased, When the molding thickness of the body portion 2a of the part is reduced), the bass characteristic of the generated sound is excellent. In that case, glass fibers may be mixed in the laminated structure of the main body 2a. Note that increasing the number of fibers in the longitudinal direction near the support shaft 12 makes it easier to produce high-pitched sounds. Also, the use of a large number of fibers in the horizontal direction at the upper part of the main body 2a and the upper part of the bent part 30 increases the rigidity. In addition, the weight can be reduced, the wall thickness can be reduced, and the high sound characteristics can be improved.

  As described above, the self-standing flat speaker 1 is elastically oscillated with respect to the mounting portion 2b around the support shaft 12 that is a connecting portion with the mounting portion 2b when the main body 2a vibrates due to sound generation. Since the generated sound moves to the low frequency range when the vibration of the main body 2b is large, the upper side of the main body 2a is related to the low frequency side of the generated sound from one viewpoint. It can be said that it has a sound region distribution characteristic that becomes a region and a region where the lower side of the main body 2b is related to the high sound region side of the generated sound.

  An example of the experimental result showing the sound range distribution characteristics of such a self-standing flat speaker 1 is shown in FIGS. 8 to 12 show experimental results when the vibration generator 20 having the same frequency characteristic is attached to the positions A to E shown in FIG. 1, and FIGS. 13 to 16 show the main body 2a. FIG. 17 to FIG. 27 show experimental results when the fibers constituting the diaphragm 2 have low elasticity in the vicinity of the support shaft 12, which is a connection part between the mounting part 2b and FIG. The experimental result at the time of changing the frequency characteristic of 20 and adjusting the attachment position is shown.

First, FIG. 8 to FIG. 12 which are experimental results when the vibration generator 20 having the same frequency characteristic is attached to each position A to E will be referred to.
FIG. 8 is a frequency characteristic graph of experimental data at a predetermined time point when the vibration generator 20 is attached to the center position A shown in FIG. 1, where the horizontal axis represents frequency (unit: Hz) and the vertical axis represents sound. (The unit is Pascal (Pa)) (the horizontal axis and the vertical axis are the same in FIGS. 9 to 12). Further, this data was obtained by measuring the sound emitted from the speaker 1 with the accelerometer in a state where the accelerometer is directly attached to the main body 2a in the direction perpendicular to the diaphragm 2 (FIGS. 13 to FIG. 13). 27 is the same). As shown in the figure, the frequency characteristics of the vibration generator 20 appearing that the sound is strong in the low frequency range on the left side and weak in the high frequency range on the right side.

  On the other hand, FIG. 9 is a frequency characteristic graph of experimental data at a predetermined time when the vibration generator 20 is attached to the upper position C (5 cm from the top) shown in FIG. As shown in the figure, it can be seen that the generated sound has moved to the low frequency range (relative to the center position A) (the intensity of the sound has increased in the low frequency range) compared to FIG. FIG. 10 is a frequency characteristic graph of experimental data at a predetermined time when the vibration generator 20 is attached to the lower position B (5 cm from the bottom) shown in FIG. As shown in the figure, it can be seen that the generated sound moves to the high frequency range side (relative to the center position A) (the intensity of the sound increases in the high frequency range) as compared to FIG.

  FIG. 11 is a frequency characteristic graph of experimental data at a predetermined time when the vibration generator 20 is attached to the right position D or the left position E shown in FIG. As shown in the figure, compared to FIG. 8 (relative to the center position A), the sound range distribution of the generated sound is not significantly changed. FIG. 12 is a frequency characteristic graph of experimental data at a predetermined time when the vibration generators 20 are attached to the two positions of the center position A and the upper position C shown in FIG. As the weight of the vibration generator 20 increases, the vibration of the diaphragm 2 increases, and the generated sound shifts to maintain the low sound (the sound is weak in the high sound range). In particular, the sound is stronger at the left end (bass side) of the horizontal axis, and the width of the vibration wave is larger than that in FIG.

Next, FIG. 13 to FIG. 16 which are experimental results when the fibers constituting the diaphragm 2 are made low elastic in the vicinity of the support shaft 12 which is a connecting portion between the main body 2a and the mounting portion 2b will be referred to.
13 and 14 are frequency characteristic graphs of experimental data at a predetermined time when the vibration generator 20 is attached to the center position A shown in FIG. 1, where the horizontal axis of FIG. Hz), and the vertical axis represents sound intensity (Pa). Further, the horizontal axis of FIG. 14 is frequency (Hz), and the unit of the vertical axis is decibel (dB). As described above, when the fiber is made highly elastic in the vicinity of the position B, the high-pitched sound characteristic of the generated sound is excellent, but conversely, the fiber is lowered in the vicinity of the position B as shown in FIG. 13 (FIG. 14). When elastic, the generated sound shifts to the low frequency range (compared to FIG. 8), and the sound intensity becomes smaller than that of FIG.

  On the other hand, FIGS. 15 and 16 are frequency characteristic graphs of experimental data at a predetermined time when vibration generators are attached to the left and right positions D and E shown in FIG. 1, respectively. Specifically, a horizontal line segment (parallel to the mounting part 2b) within the width dimension of the main body part 2a passing through the center position A is divided into four equal parts, and a position 1/4 from the left end or right end of the line segment, The vibration generator 20 was attached to the 2/4 position and the 3/4 position, respectively. Here, the horizontal axis of FIG. 15 is frequency (Hz), and the vertical axis is sound intensity (Pa). In FIG. 16, the horizontal axis represents frequency (Hz) and the vertical axis represents decibel (dB). As shown in the figure, resonance occurs with an increase in the number of vibration generators 20, and the sound intensity is larger than that in the case of FIG.

Lastly, referring to FIGS. 17 to 27, which are experimental results when the attachment position is adjusted by changing the frequency characteristics of the vibration generator 20 in the intermediate-rigid diaphragm.
17 to 19 are frequency characteristic graphs of experimental data at a predetermined time when the vibration generator 20 having excellent bass characteristics is attached to the upper position C shown in FIG. Here, the horizontal axis in FIG. 17 is frequency (Hz), the vertical axis is sound intensity (Pa), the horizontal axis in FIG. 18 is frequency (Hz), and the unit of the vertical axis is decibel (dB). FIG. 19 is a graph when music is played, in which the horizontal axis represents frequency (Hz) and the vertical axis represents decibel (dB) (the same applies to FIGS. 20 to 25). As shown in the figure, although the sound range is biased toward the low sound side, it is difficult to produce sound.

20 to 22 are graphs of experimental data at a predetermined time when the vibration generator 20 having excellent high-frequency characteristics is attached to a position close to the center position A 20 mm from the position D shown in FIG. As shown in the figure, the sound is weaker than in FIG. 8, but only a specific frequency is prevented from becoming too strong, and the sound is stronger than in FIG. 23 to 25 are combinations of FIGS. 17 to 19 and FIGS. 20 to 22. That is, it is a result when the vibration generator 20 excellent in the low sound characteristic is attached to the upper position C and the vibration generator 20 excellent in the high sound characteristic is attached to a position close to the center position A 20 mm from the position D. As shown in the figure, the sound of the extremely low sound part is stronger than in FIGS.

FIG. 26 shows an experiment in the case where other music different from that shown in FIGS. 17 to 25 is played, and the vibration generating device 20 having the low sound characteristic is attached to the position C and the vibration generating device 20 having the high sound characteristic is attached to the positions E and D, respectively. It is a result. In FIG. 27, the vibration generator 20 having excellent high sound characteristics is attached to a position close to the center position A 20 mm from the position D and a position close to the center position A 20 mm from the position E, and the low sound characteristics are excellent at the position C. It is an experimental result at the time of attaching the vibration generator 20. FIG. In both FIG. 26 and FIG. 27, the horizontal axis is frequency (Hz) and the vertical axis is decibel (dB).
As described above, in FIG. 27, a flat acoustic characteristic having a substantially constant decibel (dB) is obtained in all sound ranges.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to an above-described structure, It can change variously. For example, the vibration generation mode of the vibration generator is not limited to that of the above-described embodiment, and various vibration generation modes can be employed. In addition, a bent portion, a shape, a dimension, a formation position with respect to the diaphragm 2, and the like can be arbitrarily set. Furthermore, as long as the diaphragm is formed by FRP, its shape, dimensions, and the like can be arbitrarily set.

DESCRIPTION OF SYMBOLS 1 Self-supporting type flat speaker 2 Diaphragm 2a Main body part 2b Placement part 12 Lower surface (connection part; spindle)
20 Vibration generator 30 Bending part

Claims (10)

A substantially planar diaphragm formed of fiber reinforced plastic;
A vibration generator attached to the diaphragm and converting an input electrical signal into vibration and transmitting the vibration to the diaphragm;
With
The diaphragm is mounted on a mounting surface on which the diaphragm is to be installed, a main body that rises upward from the mounting section at a predetermined angle with respect to the mounting section, and the main body A self-standing flat speaker having a bent portion that is bent from the bent and controls a damping rate of vibration propagating through the diaphragm.   The main body is formed so as to be capable of elastically swinging with respect to the mounting portion centering on a support shaft that is a connecting portion with the mounting portion at the time of vibration accompanying sound generation. The self-supporting flat speaker according to claim 1.   The self-standing flat surface according to claim 1 or 2, wherein the bent portion is formed so that a width thereof gradually expands upward from a connection portion between the main body portion and the mounting portion. Speaker.   The self-standing structure according to any one of claims 1 to 3, wherein the diaphragm has a laminated structure formed by laminating a plurality of fiber reinforced plastic layers having different orientation directions of reinforcing fibers. Molded flat speaker. The self-supporting flat speaker according to claim 4, wherein the fiber-reinforced plastic layer includes a prepreg sheet formed by knitting reinforcing fibers in a plurality of directions.   The self-supporting flat speaker according to claim 4 or 5, wherein the reinforcing fibers are oriented in at least four directions. The self-standing flat speaker according to any one of claims 4 to 6, wherein an outer surface of the laminated structure is covered with a woven fabric.   The self-standing flat speaker according to any one of claims 1 to 7, wherein the bent portion smoothes the amplitude of vibration over the entire diaphragm.   The self-standing flat speaker according to any one of claims 1 to 8, wherein the diaphragm includes carbon fiber. 10. The system according to claim 1, wherein the upper side of the main body part is related to a low frequency side of the generated sound and the lower side of the main body part has a sound range distribution characteristic related to the high frequency side of the generated sound. The self-supporting flat speaker according to item.

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