JP5457600B1 - speaker - Google Patents

Abstract

Provided is a speaker in which sound quality is unlikely to deteriorate.
A speaker according to the present invention is provided with a vibration device on the back side of a radiation plate. Vibration generated by the vibration device 3 is transmitted to the radiation plate 2. The vibration is radiated as sound from the radiation plate 2. The radiation plate 2 is a flat plate formed of an air drying material.
[Selection] Figure 1

Description

  The present invention relates to a speaker.

  Conventionally, various types of panel-like speakers have been proposed. For example, Patent Document 1 describes a foamed plastic resonance device in which a speaker is attached to a foamed plastic plate. In this apparatus, a plate material is vibrated by sound generated from a speaker, and sound is radiated from the further vibrated plate material.

Japanese Patent Laid-Open No. 2002-64898

  However, the above-described foamed plastic resonance device has a problem that after the vibration is transmitted from the speaker to the plate material, it is difficult to spread uniformly on the plate material, and the sound quality is likely to deteriorate.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a speaker in which sound quality is unlikely to deteriorate.

The speaker according to the present invention is a speaker in which a vibration device is provided on the back side of the radiation plate, vibration generated by the vibration device is transmitted to the radiation plate, and the vibration is radiated as sound from the radiation plate. , the radiation plate Ri flat der formed by vapor dry material, transmission member for transmitting the radiation plate and vibration from the vibrating device is provided between the radiating plate and the vibrating device, wherein transmission member, characterized in Rukoto formed over the entire length of annulus direction of the radiation plate in the direction perpendicular to the fiber direction of the radiation plate.

  In this invention, it is preferable that the said transmission member is provided in the position shifted | deviated from the center of the said radiation plate.

  In the present invention, it is preferable that a transmission rod for transmitting the vibration from the vibration device to one point of the transmission member is provided between the vibration device and the transmission member.

  In the present invention, it is preferable that the vibration device includes an amplification plate that amplifies the vibration.

  In this invention, it is preferable that the back surface of the said radiation plate is formed in an uneven surface.

  In the present invention, since the radiation plate is a flat plate formed of an air-drying material, vibration is easily transmitted to the entire radiation plate through an air layer or the like existing on the flat plate of the air-drying material, and sound radiation from the radiation plate is achieved. However, it becomes easy to stabilize in a short time, and the sound quality is hardly lowered.

It is a perspective view which shows an example of embodiment of this invention. (A) is sectional drawing which shows a part of a tree, (b) is a schematic diagram which shows an annual ring, (c) is a schematic diagram which shows a conduit | pipe. An example of the vibration apparatus used for this invention is shown, (a) is a top view, (b) is a side view. It is a top view which shows the other example of the amplification board of the vibration apparatus used for this invention. It is a top view which shows the other example of the vibration apparatus used for this invention. It is a perspective view which shows an example of the transmission member used for this invention, a vibration apparatus, and a transmission rod. (A) And (b) is a schematic diagram which shows how to transmit a vibration. (A) And (b) is explanatory drawing which shows the transmission position of a vibration. It is a partial perspective view which shows an example of the radiation plate of this invention. It is a back view which shows an example of other embodiment of this invention. The other example of the radiation plate used by this invention is shown, (a) and (b) are some perspective views. It is a partial perspective view which shows the other example of the radiation plate used by this invention.

  Hereinafter, modes for carrying out the present invention will be described.

  FIG. 1 is an example of a speaker 1 according to the present embodiment. The speaker 1 includes a radiation plate 2, a vibration device 3, a transmission member 4, and a transmission rod 5.

  As the radiation plate 2, a wooden flat plate made of an air-drying material is used in order to smoothly transmit vibration to the whole. Examples of the wooden flat plate include solid wood, plywood in which a plurality of solid wood thin plates are laminated, and laminated wood in which a plurality of solid wood is combined. Among these, the radiation plate 2 is preferably formed of a solid material. In this case, energy consumption during the production of the radiation plate 2 is small, and the load on the environment can be reduced. More preferably, the radiating plate 2 is preferably made of a solid wood such as Japanese cedar or straw. In this case, it can contribute to the preservation of the forest environment and the maintenance of the forest. Moreover, the radiation plate 2 does not need to be a completely flat plate, and may be slightly warped or may have small irregularities on the surface.

  The radiation plate 2 is formed of an air drying material. An air-drying material is wood (lumber) that has been dried in the atmosphere (in the air) and is in an equilibrium state with a certain moisture content according to the temperature and humidity of the atmosphere. Further, the radiation plate 2 is preferably made of balanced wood among air-drying materials. Balanced wood is an air-drying material that is in an equilibrium state at a predetermined moisture content in an indoor air environment in which the indoor air environment is controlled to a comfortable temperature and humidity by mechanical equipment (heating device / cooling device).

General Kiinuizai is a timber ever-moisture content at a relative humidity in the atmosphere is in a state of altered equilibrium moisture content, the average equilibrium moisture content for each region and 12 months differ. According to known materials of the Japan Wood Society, the annual average equilibrium moisture content of timber in the atmosphere is about 12% in Tokyo, about 12% in the Sanyo area from the Kii Peninsula to the Seto Inland Sea, from Nagoya to the San'in area from Kita Kanto In Shikoku and Kyushu, it is about 13%. In other words, the average equilibrium moisture content of the air-drying material is about 12% to 13% balanced with the temperature and humidity in the atmosphere. Wood has a moisture content of 100% or more immediately after cutting, but the strength and function of wood vary depending on the moisture content. This is not because water is simply adsorbed, but water molecules are taken into the cell structure (hydrogen bonds), and the cell structure (hydrogen bonds) is string-like (conduit 104 formed in the late material 102, which will be described later, or early. This is because the conduit 106) formed in the material 103 is formed of a highly hydrophilic polysaccharide (cellulose, hemicellulose) in a close cage shape. The whole cell has a role of passing water (free water) (air layer 105 described later), and water molecules constitute a part of the cell by hydrogen bonding (bonded water). The standard for the moisture content of wood is determined by the Japanese Agricultural Standards (JAS). For example, the finishing material (artificial drying treatment) of a lumber product (coniferous tree) is SD15 = 15%, SD20 = 20%, the laminated lumber is an average value of 15% or less, and the natural dry conifers of flooring (floorboard) 20%, hardwood 17%, flooring (floorboard) artificial drying (mechanical drying) softwood 15%, hardwood 13%.

  Applicants have determined that the dry standard indicated by the Japanese Agricultural Standards (JAS), which has been distributed as dry wood, and the air-drying material (equilibrium moisture content of 12% to 13%) based on well-known materials of the Japan Wood Society, Paying attention to the fact that in a room air environment with high density and mechanical equipment (heating and cooling equipment), the drying of the wood further progresses and the moisture content decreases, shrinking, cracking and warping, The experiment to measure the moisture content change of wood was repeated. As a result, in an indoor air environment with high airtightness and complete mechanical equipment (heating and cooling equipment), air-drying according to the drying standards indicated by the Japanese Agricultural and Forestry Standard (JAS) and known materials of the Japan Wood Research Association It was found that the material was in a state of equilibrium water content significantly different from the material (equilibrium water content 12% to 13%). For example, in an indoor air environment in which the air environment is controlled by mechanical equipment (heating device / cooling device) with an indoor temperature of 21 ° C. to 27 ° C. and an indoor humidity of about 30%, the equilibrium moisture content of wood is 6.1% to Under an indoor air environment of 6.2%, indoor temperature 21 ° C. to 27 ° C. and indoor humidity 50%, the equilibrium moisture content of wood is 7.6% to 9.1%.

  The air-drying material used as the radiation plate 2 is about 6.1% to 12% of the moisture content mentioned above while complying with the dry quality standards of the Japanese Agricultural Standard (JAS) and public construction wooden construction standards. It is preferable to be able to follow a sudden change in water content. That is, an air-drying material (that is, balanced wood) having a moisture content drying history that has reached an equilibrium state in an indoor air environment in which the air environment is controlled by mechanical equipment (heating device / cooling device) is used as the radiation plate 2. It is preferable. It is widely known that wood has a drying history phenomenon (hysteresis), and wood with a moisture history of 6% or less has a rapid moisture content of about 6.1% to 12%. There is almost no shrinkage, cracking or warping against changes. The air-drying material formed on the radiation plate 2 is more preferably an air-drying material having a drying history in which moisture is gradually absorbed from an over-dried wood (total dry material) that hardly contains moisture and reaches an equilibrium state. Wood that has reached the equilibrium state by gradually absorbing moisture from the above-mentioned overdried wood (total dry wood) shrinks and warps due to a sudden change in the indoor air environment (temperature and humidity). The acoustic effect (sound vibration propagation) is less likely to be affected by free water or excessive water molecules. Therefore, when such an air-drying material is used as the radiation plate 2, as shown in FIG. 2 (c), vibrations propagate efficiently and are easily radiated as sound. Such a radiation plate 2 has acoustic characteristics similar to a musical instrument such as a violin. If the radiation plate 2 is not an air-drying material, the radiation of the emitted sound is difficult to stabilize, but if the radiation plate 2 is an air-drying material, the radiation of the sound is easily stabilized in a short time. Moreover, the radiation plate 2 formed of an air-drying material is preferable because it can improve the dimensional stability while enhancing the humidity control function.

  The drying method for obtaining the air-drying material used as the radiation plate 2 may be a natural drying method for drying in the air, or an artificial drying method using various drying machines. In the drying method using a drying machine, after drying, it is necessary to expose to the atmosphere (in the air) and cure until the moisture content reaches an equilibrium state. The method for obtaining the air-dried material is not limited to either the natural drying method or the artificial drying method.

  The radiation plate 2 may be either wood or lumber (timber), but a square is preferred. In the wood of a square, the grain is relatively regular. The wood grain appears randomly in the grain of wood. The vibration transmitted to the radiation plate 2 is more easily transmitted in the grain direction (fiber direction) than in the annual ring direction. Further, the radiation plate 2 has a higher specific Young's modulus and lower internal friction in the grain direction than in the annual ring direction, and can obtain a quick rise of sound and stable vibration. As shown in FIG. 2, the annual ring 100 is a ring that appears on the cross section (the end face) of the tree 101. The annual ring direction X is a direction in which a plurality of annual rings 100 are arranged, and is a radial direction of the tree 101. The grain direction (fiber direction) Y is a direction orthogonal to the annual ring direction X and is the axial direction of the tree 101. As shown in FIG. 2 (b), the annual ring 100 for one year is formed with the late material 102 and the early material 103 being continuously formed. The late material 102 is a hard part with high density. The early material 103 is a soft part with a low density. As shown in FIG. 2C, the conduit 106 formed in the early material 103 has a larger cross-sectional area (bore diameter) of the air layer 105 than the conduit 104 formed in the late material 102. Accordingly, the late material 102 has a higher density than the early material 103. The conduits 104 and 106 are formed long in the grain direction Y. A plurality of conduits 104 and 106 are arranged in the annual ring direction X. The vibration (sound) transmitted to the radiation plate 2 is more easily transmitted in the wood grain direction Y than in the annual ring direction X. The vibration in the high frequency range transmitted to the radiation plate 2 is mainly transmitted and radiated through the conduit 104 of the late material 102 having a high density. The vibration in the low frequency range transmitted to the radiation plate 2 is mainly transmitted and radiated through the conduit 106 of the early material 103 having a low density. As described above, the wooden radiating plate 2 is likely to generate vibration in which high and low sounds are mixed. Further, the wooden radiation plate 2 has less divided vibration and natural vibration, and the vibration is efficiently converted into sound. Further, the wooden radiation plate 2 has an appropriate viscosity, and the surface restitution coefficient is lower than that of metal. For this reason, even if the radiation plate 2 is vibrated by either an excitation due to an instantaneous external force or an excitation due to a continuous external force, the radiated sound becomes a “soft sound” with few high-frequency components.

  Although the radiation plate 2 is formed in an appropriate shape, for example, it is formed in a rectangular shape. Further, the size of the radiation plate 2 is appropriately formed. In the case of the rectangular radiation plate 2, for example, the longitudinal dimension is 420 to 4000 mm, the lateral dimension is 210 to 2000 mm, and the thickness is 3 to 30 mm. More specifically, the radiation plate 2 is formed to have a longitudinal dimension of 3000 mm, a lateral dimension of 1000 mm, and a thickness of 30 mm. The longitudinal direction of the radiation plate 2 is preferably parallel to the fiber direction (grain direction Y). Moreover, it is preferable that the short side direction of the radiation plate 2 is parallel to the annual ring direction X. In addition, the parallel here is not parallel in a strict sense, and may be slightly shifted. If the longitudinal direction of the radiation plate 2 is parallel to the fiber direction, vibrations are easily transmitted in the longitudinal direction of the radiation plate 2, and vibrations are easily transmitted uniformly throughout the radiation plate 2. Moreover, it is preferable that the specific gravity of the radiation plate 2 is 0.3-0.65.

  A coating film may be formed on the surface of the radiation plate 2 (surface from which sound is emitted). Thereby, the sound radiated from the radiation plate 2 changes. For example, if a coating film having a hardness higher than that of wood is formed on the surface of the radiation plate 2, a hard and high sound is likely to be emitted. Examples of the coating film include lacquer and urethane paint. The coating film may be provided over the entire surface of the radiation plate 2 or may be provided in a part.

  As shown in FIGS. 3A and 3B, the vibration device 3 includes an actuator 30 and an amplification plate 31.

  The actuator 30 converts an electrical signal of sound input from an amplifier or the like into vibration. The actuator 30 includes a magnet 301, a voice coil 302, a cap 303, and a drive member 304. The magnet 301 is provided substantially at the center of the surface of the pedestal 32. The magnet 301 is provided with a receiving groove 305 that opens on the surface thereof. The housing groove 305 is formed in an annular shape in plan view (viewed from the surface side of the magnet 301). The voice coil 302 is formed in a ring shape. The voice coil 302 is accommodated in the accommodation groove 305. The cap 303 is formed of a thin disc made of plastic. The cap 303 holds the voice coil 302 so that it does not fall out of the receiving groove 305. The cap 303 is provided on the surface of the magnet 301 so as to close the opening of the accommodation groove 305. The drive member 304 is made of paper such as cardboard and is formed in a cylinder or the like. The diameter of the drive member 304 is formed substantially equal to the diameter of the voice coil 302. The driving member 304 is provided on the surface of the cap 303. At this time, the position of the end of the voice coil 302 matches the position of the end of the drive member 304. That is, the end of the voice coil 302 and the end of the drive member 304 are disposed to face each other with the cap 303 interposed therebetween.

  The amplifying plate 31 is used to transmit vibration from the actuator 30 to the transmission member 4 more smoothly. The amplifying plate 31 is a rectangular flat plate. The amplifier plate 31 is formed of a wooden flat plate, a metal flat plate, a plastic flat plate, or the like. Examples of the wooden flat plate include solid wood, medium density fiberboard (MDF), particle board, plywood, and laminated wood. Among these, the amplification plate 31 is preferably formed of a solid material. The amplification plate 31 is preferably formed of an air-drying material, and more preferably formed of balanced wood, like the radiation plate 2. The specific gravity of the amplifier plate 31 is also preferably 0.3 to 0.65. Further, the amplifying plate 31 may be either a grid or a piece of wood (timber), but a grid is preferred. Further, the grain direction of the amplification plate 31 is preferably parallel to the longitudinal direction of the amplification plate 31, so that vibration is easily transmitted to the entire amplification plate 31. Examples of the metal flat plate include an aluminum plate. An acrylic board etc. can be illustrated as a plastic flat plate. The amplifying plate 31 does not have to be a completely flat plate, and may be slightly warped or have small irregularities on the surface.

  The amplification plate 31 is disposed to face the pedestal 32. At both ends in the longitudinal direction of the vibration device 3, the longitudinal end of the amplification plate 31 and the longitudinal end of the pedestal 32 are connected by a connecting member 34. The amplification plate 31 and the connecting member 34, and the pedestal 32 and the connecting member 34 are connected by adhesion or the like. An actuator 30 is provided between the amplification plate 31 and the base 32. The tip of the drive member 304 of the actuator 30 is in contact with the back surface (the surface facing the pedestal 32) of the amplification plate 31. The front end of the drive member 304 and the back surface of the amplification plate 31 are not bonded, but may be bonded. The amplifier plate 31 has a function of protecting the actuator 30 in addition to the function of amplifying vibration.

  A fixed base 33 is provided on the surface of the amplification plate 31. The fixed base 33 is made of wood, metal, plastic, or the like, and is formed in a columnar shape, for example. The fixing base 33 is provided at the center of the surface of the amplification plate 31. The circular bottom surface of the fixing base 33 is bonded to the surface of the amplification plate 31.

  A transmission bar 5 is provided on the fixed base 33. The transmission bar 5 is made of a bar material made of wood, metal, plastic or the like. The transmission rod 5 is formed to have a diameter smaller than the diameter of the fixed base 33, and is formed to have a diameter of 5 to 9 mm, for example. The transmission rod 5 is fixed to the fixing base 33 by being inserted from the center of the front end surface thereof. The distal end of the transmission rod 5 protrudes from the center of the distal end surface of the fixed base 33.

  The vibration device 3 generates vibration based on an electrical signal of sound. That is, when an electric signal is input from the amplifier or the like to the voice coil 302 of the actuator 30 and a current flows, the voice coil 302 vibrates due to the magnetism of the magnet 301. Since the voice coil 302 is in contact with the driving member 304 via the cap 303, the vibration of the voice coil 302 is transmitted to the driving member 304. Since the drive member 304 is in contact with the amplification plate 31, the vibration of the drive member 304 is transmitted to the amplification plate 31. And the transmission rod 5 vibrates with the vibration of the amplification plate 31. In this way, vibration can be generated by the vibration device 3.

  The longitudinal dimension (vibration width) H of the vibrating portion of the amplification plate 31 is the same as the dimension between the two connecting members 33. This vibration width H is formed larger than the diameter D of the voice coil 302. Therefore, when the vibration of the voice coil 302 is transmitted to the amplification plate 31, almost the entire amplification plate 31 vibrates and becomes larger than the vibration width (same as the diameter D) of the vibration of the voice coil 302. In this way, the vibration width of the vibration of the voice coil 302 is amplified by the amplification plate 31.

  The volume and sound range radiated from the radiation plate 2 of the amplification plate 31 are changed according to the material, dimensions, vibration width H, and the like. For example, as shown in FIG. 4, the volume and the sound range are changed by a plurality of slits 312 provided in the amplification plate 31. The amplifying plate 31 has its vibration width H changed depending on the material, plate thickness, the number and size of the slits 312, and the volume and sound range radiated from the radiation plate 2 can be adjusted.

  The vibration device 3 is formed in a rectangular shape in plan view, but is not limited thereto. For example, as shown in FIG. 5, the vibration device 3 may be circular when viewed from above. In this case, the pedestal 32 is a circular plate, the end of the amplification plate 31 in the longitudinal direction is arcuate, and the connecting member 34 is curved. Other configurations are the same as those of the vibration device 3 shown in FIG. The same.

  The transmission member 4 is for smoothly transmitting vibration from the vibration device 3 to the radiation plate 2. As shown in FIG. 6, the transmission member 4 is formed of a rectangular flat plate or square member. The transmission member 4 is made of wood, metal, plastic or the like. Examples of the wooden transmission member 4 include solid wood, medium density fiberboard (MDF), particle board, plywood, and laminated wood. Among these, the transmission member 4 is preferably formed of a solid material. Further, like the radiation plate 2, the transmission member 4 is preferably formed of an air-drying material, and more preferably formed of balanced wood. The specific gravity of the transmission member 4 is preferably 0.3 to 0.65. Further, the transmission member 4 may be either wood or lumber, but a square is preferable. Moreover, it is preferable that the grain direction Y of the transmission member 4 is parallel to the longitudinal direction of the transmission member 4, so that vibration is easily transmitted to the entire transmission member 4. Examples of the metal transmission member 4 include an aluminum plate. An example of the plastic transmission member 4 is an acrylic plate. Further, the transmission member 4 does not have to be a completely flat plate, and may be slightly warped or have small irregularities on the surface.

  The dimension in the longitudinal direction of the transmission member 4 can be formed to be the same as or slightly shorter than the dimension in the short direction of the radiation plate 2. Moreover, the dimension of the transversal direction of the transmission member 4 can be 12 to 100 mm, preferably 20 mm, and the thickness of the transmission member 4 can be 9 to 20 mm, preferably 15 mm, but is not limited thereto.

  The speaker 1 of the present embodiment is formed by integrating the radiation plate 2, the transmission member 4, and the vibration device 3. The transmission member 4 is attached to the back surface of the radiation plate 2 by adhesion or the like. In this case, the transmission member 4 is provided so that the longitudinal direction thereof is orthogonal to the longitudinal direction of the radiation plate 2, that is, the fiber direction (grain direction Y). The transmission member 4 is provided over the entire length of the radial plate 2 in the short direction, that is, the annual ring direction X. In the present specification, the term “orthogonal” is not used in a strict sense, and may intersect slightly from 90 °. “Parallel” is not used in a strict sense, and may be almost parallel. Further, the “full length” is not used in a strict sense, and may be slightly longer or shorter than the full length. The vibration device 3 is provided on the back surface side of the transmission member 4 (the surface not bonded to the radiation plate 2). In this case, as shown in FIG. 6, a coupling hole 41 is provided at a substantially central portion in the longitudinal direction of the transmission member 4, and the transmission rod 5 of the vibration device 3 is inserted into the coupling hole 41. The transmission member 4 and the transmission rod 5 may be bonded or may not be bonded.

  Although it is possible to provide a plurality of vibration devices 3 for one radiation plate 2, it is preferable to provide one vibration device 3 for one radiation plate 2. When a plurality of vibration devices 3 are provided, vibrations generated from the vibration devices 3 may interfere with each other, which may make it difficult for the sound to spread uniformly over the entire radiation plate 2 or reduce the sound quality.

  In such a speaker 1, vibration generated by the actuator 30 of the vibration device 3 is transmitted to the amplification plate 31, the fixing base 33 and the transmission rod 5, and this vibration is transmitted from the transmission rod 5 to the transmission member 4, and further the transmission member 4 is transmitted to the radiation plate 2. And the vibration transmitted to the radiation plate 2 is radiated and diffused in the air as sound. When transmitted from the transmission rod 5 to the transmission member 4 as described above, as a point sound source, that is, vibration is transmitted intensively to one point. In this case, sound is radiated uniformly with a wide sound range and wide directivity.

  Here, the speaker 1 is easy to transmit the vibration uniformly to the whole radiation plate 2 by the transmission member 4, and the sound quality is not easily lowered. That is, as shown in FIG. 7A, when the transmission member 4 is not provided, the radiation plate 2 and the vibrating bar 5 are directly connected, so that vibration is intensively supplied to one point of the radiation plate 2, and gradually from here. Therefore, the vibration is transmitted to the entire radiation plate 2. Therefore, the vibration tends to spread in the wood grain direction (fiber direction) Y of the radiation plate 2, but the vibration hardly spreads in the annual ring direction X, and the sound radiation area S becomes small. On the other hand, as shown in FIG. 7B, when the transmission member 4 is present, the radiation plate 2 and the vibrating bar 5 are connected via the transmission member 4, so that vibration is intensively supplied to one point of the transmission member 4. After that, this vibration is transmitted over the entire length of the transmission member 4, and the vibration is gradually transmitted from here to the entire radiation plate 2. Therefore, the transmission member 4 makes it easier for vibration to be transmitted in the annual ring direction X of the radiation plate 2, and the sound radiation area S becomes larger.

  Further, in the plan view of the radiation plate 2, the position of the transmission rod 5 is preferably set at a position shifted from the center O of the radiation plate 2. As a result, the vibration generated from the vibration device 3 is avoided from resonating and increasing, and the sound quality is unlikely to deteriorate.

  The position of the transmission rod 5 in the plan view of the radiation plate 2 is preferably set as follows. First, as shown in FIG. 8A, in a plan view of the radiation plate 2, the radiation plate 2 is divided into 1/3 portions in the longitudinal direction and also divided into 1/3 portions in the short direction. Of the nine blocks formed in this way, the block B located in the middle is further divided into 1/3 parts in the longitudinal direction and into 1/3 parts in the short direction. And among the blocks divided into nine blocks B, it is preferable that the transmission rod 5 is located at either the short side C1 or C2 of the middle block C. Further, as shown in FIG. 8B, the transmission member 4 is preferably provided so as to pass through the position of the short side C1 or C2.

  And the speaker 1 of this Embodiment has the following effects. By using an air-drying material as the radiation plate 2, the transmission member 4, and the amplification plate 31, it adapts to changes in the indoor air environment and is less likely to crack or deform. Moreover, since a static electricity is not charged by mainly using a wooden member, it becomes difficult to produce an electrical stress. Further, since the cell structure (conduit) of the radiation plate 2 includes a large amount of the air layer 105, the sound radiated from the radiation plate 2 tends to be a “soft sound” with few high-frequency components. Further, since the radiation plate 2 has subtle irregularities based on the cell structure, the light is repeatedly irregularly reflected, whereby ultraviolet rays are absorbed, glare (glare) can be reduced, and the eyes are not easily fatigued. In addition, a highly hydrophilic cell structure has a “humidity control function” that equilibrates at the molecular level so that the water retention state is always constant, and the installed room tends to be comfortable. In addition, wood has a unique scent that calms people's minds, so it is easy to reduce fatigue and stress with sound, and it is easy to get relaxed. Since there are annual rings on the grain and the annual ring width is not constant, it is considered that there is 1 / f fluctuation in the interval between the annual rings with different growth conditions depending on the natural environment. This fluctuation is easy to give people a natural deep image. The use of wood can contribute to carbon dioxide fixation and forest environment conservation. Further, no enclosure is required, no standing wave is generated, and deterioration of sound quality can be reduced.

  FIG. 9 shows another example of the radiation plate 2. The radiation plate 2 is formed by combining a plurality of radiation plate members 21, 22, 23 of different types. Here, the different types can be exemplified by the presence or absence of the coating film, the material, or the thickness. Further, a combination of a plate material and a mesh material may be used. Such a radiation plate 2 can radiate more various sounds than the radiation plate 2 formed of a single material or thickness.

  10 and 11 show another speaker 1 having a different radiation plate 2. In the radiation plate 2, a plurality of grooves 25 are formed on the back surface thereof. Thereby, the radiation plate provided with the groove 25 is formed as an uneven surface, and the sound radiation surface is increased as compared with the flat radiation plate 2, and it is easy to emit bass. Therefore, it is suitably used as a speaker for a woofer. The width of the groove 25 may be 3 to 4 mm, the depth of the groove 25 may be 3 to 10 mm, and the interval between adjacent grooves 25 may be 12 to 30 mm, but is not limited thereto. Further, the groove 25 is provided so that the longitudinal direction thereof is orthogonal to the longitudinal direction of the radiation plate 2, that is, the fiber direction (grain direction Y). Further, the groove 25 is provided over the entire length in the short direction of the radiation plate 2, that is, the annual ring direction X.

  FIG. 12 shows another example of the radiation plate 2. The radiation plate 25 is composed of a low sound radiation part 26 and a high / middle sound radiation part 27. The low sound radiating portion 26 is thicker than the high / mid sound radiating portion 27 and is provided with a plurality of grooves 25 similar to the above. The low sound emitting portion 26 is provided on both sides of the longitudinal end portion of the high and medium sound emitting portion 27. The transmission member 4 is disposed across the low sound emitting portion 26 and the high / mid sound emitting portion 27. For example, the bass radiating portion 26 includes a portion having a specific gravity of 0.4 to 0.6 and a relatively low density of cedar slats, and the high and medium sound radiating portion 27 is a wood having a specific gravity of 0.3 to 0.65, preferably It is preferable to include many parts with relatively high density of wood and cedar board.

  In this way, the radiation plate 2 can be formed in consideration of the balance of radiation between the low sound range and the high mid sound region. In addition, when forming the back surface of the radiation plate 25 on the uneven surface as described above, the back surface of the radiation plate 25 is made uneven by providing a plurality of rod-shaped members on the back surface in addition to forming the plurality of grooves 25. It is also possible to form it on the surface.

DESCRIPTION OF SYMBOLS 1 Speaker 2 Radiation plate 3 Vibration apparatus 4 Transmission member 5 Transmission rod 31 Amplification plate

Claims (5)

A vibration device is provided on the rear surface side of the radiation plate, and a vibration generated by the vibration device is transmitted to the radiation plate, and the vibration is radiated as sound from the radiation plate, and the radiation plate is air-dried. Ri flat der formed by wood, the transmission member for transmitting the radiation plate vibrations from the vibrating device is provided between the radiating plate and the vibrating device, wherein the transmission member of the radiating plate speakers, wherein Rukoto formed in a direction perpendicular to the fiber direction over the entire length of the annulus direction of the radiation plate. The speaker according to claim 1 , wherein the transmission member is provided at a position shifted from a center of the radiation plate. The speaker according to claim 1 or 2 , wherein a transmission rod for transmitting the vibration from the vibration device to one point of the transmission member is provided between the vibration device and the transmission member. Speaker according to any one of claims 1 to 3 wherein the vibrating device, comprising the amplifying plate where the vibration is amplified. The speaker according to any one of claims 1 to 4 , wherein a back surface of the radiation plate is formed as an uneven surface.

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