Speaker

Abstract

To provide a speaker which has few restrictions on installation, can secure sufficient sound pressure even at a low frequency, and can provide sound with presence to a user.SOLUTION: A speaker 1 includes an electrostatic speaker unit 5 having flexibility and including one side 5a and the other side 5b, and an enclosure 4 having flexibility and covering at least a part of the one side 5a side of the speaker unit 5. The enclosure attenuates the sound pressure emitted from the one surface of the speaker unit by air resistance and viscous resistance of the structure, prevents waves of the sound pressure output from the one surface and the other surface of the speaker unit from interfering and canceling each other, and secures sufficient sound pressure even at a low frequency.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to speakers. [Background technology]

[0002] Conventionally, sound pressure-electrical signal converters (e.g., speakers) that convert electrical signals into sound pressure (sound) have been known. Conventional speakers generally have a metal structure that uses an electromagnet to convert signals through electromagnetic induction. However, because they are made of metal, they lack flexibility, making it difficult to install the speaker so that it conforms to the installation location. Even if it were possible to install a speaker outside the installation location, this often compromises the overall aesthetic appeal of the device. One solution to this problem is to embed the speaker in the installation location, but this requires sufficient space inside the installation location to embed the speaker, which places significant restrictions on installation.

[0003] Electrostatic speakers have been proposed that utilize electrostatic force to generate sound pressure in a space. This type of electrostatic speaker is flexible and can conform to the installation location. Patent Document 1 discloses a flexible electrostatic speaker that has a structure in which a dielectric film is disposed between a pair of opposing conductive fibers. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-16094 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the electrostatic speaker disclosed in Patent Document 1 necessarily has a small mass because it must use fibers and films, making it difficult to generate low-frequency sound pressure, and therefore, it is difficult for the electrostatic speaker disclosed in Patent Document 1 to provide users with realistic sound.

[0006] Therefore, an object of the present disclosure is to provide a speaker that has few restrictions on installation and can ensure sufficient sound pressure even at low frequencies. [Means for solving the problem]

[0007] An example of an aspect provided by the present disclosure is as follows. [1] a flexible electrostatic speaker unit having one surface and another surface; a flexible enclosure that covers at least a portion of the one surface of the speaker unit. [2] Item 2. The speaker according to item 1, wherein the enclosure has a bending resistance of 300 mm or less. [3] 3. The speaker according to item 1 or 2, wherein the enclosure has an air permeability of 0.1 cm3 / cm2·s or more. [4] 4. The speaker according to any one of items 1 to 3, wherein the Young's modulus of the enclosure is 1 GPa or less. [5] 5. The speaker according to any one of items 1 to 4, wherein the minimum bending radius of the enclosure is 80 mm or less. [6] 6. The speaker according to any one of items 1 to 5, wherein the enclosure is a three-dimensional knitted fabric including a knitted fabric of a surface layer, a knitted fabric of a back layer, and a connecting yarn that connects the knitted fabric of the surface layer and the knitted fabric of the back layer. [7] 7. The speaker according to any one of items 1 to 6, wherein the average thickness of the enclosure is greater than 0 mm and equal to or less than 30 mm. [8] The speaker unit has a structure in which a dielectric layer is disposed between a pair of opposing conductive layers, and when an electric signal is applied to the pair of conductive layers, the pair of conductive layers and the dielectric layer vibrate together to generate sound pressure. The speaker described in any one of items 1 to 7. [9] Item 9. The speaker according to item 8, wherein the conductive layer is made of conductive fibers.

[10] 10. The speaker according to item 8 or 9, wherein the one surface is a surface that intersects with the vibration direction.

[11] 11. The speaker according to any one of items 8 to 10, wherein the one surface and the other surface are both surfaces that intersect with the displacement direction of the conductive layer. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a speaker that has few restrictions on installation and can ensure sufficient sound pressure even at low frequencies. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing an example of the configuration of a speaker according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] An example of an aspect (embodiment) provided by the present disclosure will be described below. However, the aspect provided by the present disclosure is not limited to the aspect described below, and therefore various modifications are possible within the scope of the gist of the present invention.

[0011] In this disclosure, various measurements are made based on the methods described in the Examples unless otherwise specified. In the present disclosure, in numerical ranges described in stages, the upper or lower limit value described in a certain numerical range may be replaced by the upper or lower limit value of another numerical range described in stages, or may be replaced by a value shown in the Examples. In the contents shown in the drawings, the scale, shape, and length may be exaggerated for clarity.

[0012] [First embodiment] [speaker] The speaker provided by the present disclosure comprises: An electrostatic speaker unit (hereinafter simply referred to as a "speaker unit") that is flexible and has one surface and another surface; and a flexible enclosure that covers at least a portion of the one surface of the speaker unit.

[0013] FIG. 1(a) is a cross-sectional view showing an example of the configuration of a speaker according to the present disclosure. As shown in the figure, the speaker 1 includes a speaker unit 5 and an enclosure 4. One surface 5a and the other surface 5b of the speaker unit 5 extend in the x-axis direction and the y-axis direction, respectively, and the enclosure 4 is stacked in the z-axis direction on the side of one surface 5a of the speaker unit 5.

[0014] The enclosure 4 may be laminated directly onto one surface 5a of the speaker unit 5, or may be laminated via another layer. In the drawing, the length (thickness) of the speaker unit 5 in the z-axis direction is represented by the symbol t, and the length (thickness) of the enclosure 4 in the z-axis direction is represented by the symbol t'.

[0015] As an example, the speaker unit 5 has a structure in which a dielectric layer 2 is disposed between a pair of opposing conductive layers 3, 3'. When an electric signal is applied to the pair of conductive layers 3, 3', the pair of conductive layers 3, 3' and the dielectric layer 2 vibrate (displace) together along the z-axis direction, thereby generating sound pressure. That is, one surface 5a and the other surface 5b are located as surfaces that intersect in the vibration direction (displacement direction) of the pair of conductive layers 3, 3' and the dielectric layer 2, and the enclosure 4 is laminated on the one surface 5a side.

[0016] As the pair of conductive layers 3, 3' and the dielectric layer 2 vibrate, sound pressure is output from, for example, one side 5a and the other side 5b. At this time, the user can experience more realistic sound pressure by facing the sound pressure output side toward themselves. When the other side 5b is facing the user, the other side 5b is perceived as the "front" by the user, and the opposite side 5a is perceived as the "rear" by the user.

[0017] It is preferable that the speaker has flexibility as a whole structure in order to reduce installation restrictions. From this viewpoint, the bending resistance of the speaker may be, for example, 300 mm or less, 250 mm or less, 220 mm or less, or 200 mm or less. The bending resistance of the speaker may also be greater than 0 mm, 5 mm or more, or 10 mm or more. The bending resistance of the speaker can be measured in accordance with JIS-L-1096:2010, Method A (45° cantilever method) using a 45° cantilever type testing machine.

[0018] As described above, the speaker is not limited to an embodiment including only a speaker unit and an enclosure, and may include layers other than these (other layers). In this regard, one preferred embodiment of the speaker is one that does not include any rigid parts other than the speaker unit and the enclosure. Therefore, if the speaker includes the other layers, it is preferable that these other layers also have flexibility.

[0019] <Speaker unit> The speaker unit is an electrostatic speaker unit and is flexible. In this disclosure, the term "electrostatic speaker unit" refers to a sound pressure-electrical signal converter, such as a speaker, that converts an electrical signal into sound pressure (sound). The sound pressure-electrical signal converter utilizes electrostatic force to generate sound pressure in a space.

[0020] With regard to a speaker unit, "having flexibility" means having flexibility to the extent that it does not hinder the speaker from conforming to the installation location. A speaker unit is likely to have suitable flexibility by having a bending resistance, which will be described later.

[0021] The bending resistance of the speaker unit is preferably 300 mm or less, more preferably 250 mm or less, even more preferably 220 mm or less, and particularly preferably 200 mm or less. When the bending resistance of the speaker unit is in this range, the speaker can be installed in applications requiring flexibility without impeding that flexibility, and the speaker can be installed to conform to complex shapes. The bending resistance of the speaker unit may be greater than 0 mm, 5 mm or more, or 10 mm or more. For the method of measuring the bending resistance of a speaker unit, please refer to the contents described in the [Speaker] column.

[0022] The thickness of the speaker unit is preferably 30 mm or less, more preferably 20 mm or less, and even more preferably 10 mm or less. Having the speaker unit thickness within this range makes it easy to achieve a texture similar to fabric. Furthermore, the speaker can be installed in applications requiring flexibility without impeding that flexibility, and the speaker can be installed to conform to complex shapes. From the perspective of ease of installation, the speaker unit thickness should preferably be 1 mm or more. The "thickness of the speaker unit" referred to here is represented by the symbol t in the figure.

[0023] Conductive layer The material used for the conductive layer may be any material that can ensure conductivity in the in-plane direction (xy in-plane direction in the drawing), and is preferably a conductive fiber from the viewpoint of excellent flexibility. Conductive fibers include: Chemical fibers containing highly conductive materials (metal, carbon black, etc.), The fiber surface is coated with metal and conductive resin, Metal fibers made by turning metal into fibers, as well as knitted and woven fabrics and fabrics including nonwoven fabrics vapor-deposited with metal; and the like. Among these, from the viewpoint of excellent flexibility and light weight, the conductive fibers are preferably fibers coated with a metal such as titanium, gold, silver, copper, nickel, or aluminum. Preferred coating methods include plating, sputtering, and vapor deposition.

[0024] Dielectric layer The material used for the dielectric layer is preferably one that can ensure flexibility and can ensure insulation between the pair of conductive layers, and is preferably, for example, a flexible polymer material. Examples of flexible polymeric materials include elastomers, thermoplastic resins, thermosetting resins, and rubbers. More specifically, Examples include natural rubber, urethane rubber, acrylic rubber, silicone rubber, butadiene rubber, nitrile group-containing rubber (nitrile rubber, hydrogenated nitrile rubber, etc.), isoprene rubber, vulcanized rubber, styrene-butadiene rubber, butyl rubber, chlorosulfonated polyethylene rubber, ethylene propylene rubber, fluorine-based polymers, silicone-based polymers, and ethylene-based polymers. The dielectric layer is preferably a film, particularly a dielectric film that is prone to undergo dielectric polarization when sandwiched between conductive layers having positive and negative charges.

[0025] <Flexible base material> The speaker may include a flexible substrate separate from the speaker unit and the enclosure. The flexible substrate is preferably breathable. In one aspect, the speaker may include flexible substrates between the speaker unit and the enclosure, on the outside of the speaker unit, on the outside of the enclosure, etc.

[0026] For a flexible substrate, "breathability" means that the sound pressure generated by the vibration of the conductive layer is not hindered from escaping to the outside, and means, for example, that the air permeability is 1 cm3 / cm2·s or more, preferably 3 cm3 / cm2·s or more, and more preferably 5 cm3 / cm2·s or more. Air permeability, i.e., the air permeability in the thickness direction, is measured using a Frazier-type testing machine in accordance with JIS-L-1096, 1018 Air Permeability Test Method (Method A Air Volume).

[0027] The flexible substrate may be selected from the group consisting of, for example, knitted fabric, woven fabric, leather, artificial leather, synthetic leather, nonwoven fabric, resin sheet, rubber sheet, film, moisture-permeable waterproof sheet, three-dimensional resin shaped object, and three-dimensional knitted fabric.

[0028] The flexible substrate does not need to be a single layer, but may be a laminate of multiple layers. When the flexible substrate is a laminate of multiple layers, the materials constituting each layer may be the same or different. By providing multiple layers made of different materials, the flexible substrate can easily exhibit various functions according to the materials. The flexible substrate may perform a cushioning function to protect the speaker unit from external stimuli. Such a function is easily exhibited when the flexible substrate is made of, for example, a knitted fabric, a woven fabric, a three-dimensional knitted fabric, or the like.

[0029] <Cushion layer> Speakers are handled by users. For example, it is assumed that a user may touch the speaker, which may result in the application of pressure. When a speaker is installed in a location where such pressure, specifically a compressive force that may compress the speaker, is expected, it is preferable to provide a layer (cushion layer) that acts as a cushion on the outside of the speaker unit (i.e., on the outside of the pair of conductive layers) so that the vibration of the vibrating part (i.e., the part of the speaker unit that displaces in response to an electrical signal) is not hindered even when a compressive force is applied to the speaker. The cushion layer may be made of any material that ensures breathability and cushioning, such as urethane foam, a three-dimensional resin model, a three-dimensional knitted fabric, etc. Among these, three-dimensional knitted fabrics are preferred as the cushion layer because they provide excellent breathability during compression. In the speaker, the cushion layer may also serve as the flexible substrate, or the speaker may include a cushion layer in addition to the flexible substrate. When the speaker includes a flexible substrate and a cushion layer, the stacking order of these layers is not particularly limited.

[0030] <enclosure> The enclosure is flexible and covers at least a portion of the one surface of the speaker unit. In the speaker, sound pressure is output from both the one surface and the other surface of the speaker unit, and the enclosure covers at least a portion of one of these surfaces. By providing a speaker with an enclosure, the sound pressure emitted from one side of the speaker unit can be attenuated by air resistance and the viscous resistance of the structure, thereby preventing the sound pressure waves output from one side and the other side of the speaker unit from interfering with and canceling each other, thereby ensuring sufficient sound pressure even at low frequencies.

[0031] With regard to the enclosure, "having flexibility" means having flexibility to the extent that it does not hinder the speaker from conforming to the installation location. The enclosure is likely to have suitable flexibility by having a bending resistance, which will be described later. The "flexibility" of the enclosure may be the same as or different from the "flexibility" of the speaker unit.

[0032] The enclosure preferably has a structure in which an air layer is partitioned by, for example, flexible walls. In this case, the enclosure includes, for example, flexible walls and an air layer disposed inside the walls. The walls may have a non-ventilated structure or a breathable structure. Furthermore, as described below, the wall may be formed directly from a structure in which structures are connected. The walls preferably have a dense structure capable of reflecting sound. Having a sound-reflecting structure in the walls makes it easier to attenuate low-frequency sounds due to air resistance and the viscous resistance of the structures within the enclosure, thereby making it easier to prevent sound pressure waves output from one side and the other side of the speaker unit from interfering with and canceling each other. Therefore, it is easier to ensure sufficient sound pressure even at low frequencies. Here, it is preferable that the enclosure has a structure that includes an air layer and a breathable structure (fiber, foam, etc.) inside the wall surface, which makes it easy to ensure flexibility and also makes it easy to ensure sufficient volume inside the wall surface to withstand external loads. The enclosure need not be a single layer, but may be a laminate of multiple layers, in which case the materials constituting each layer may be the same or different.

[0033] Alternatively, regardless of whether the enclosure includes the wall surface, the structure to which the enclosure is to be placed may be a structure that serves as a wall surface that reflects sound. A structure in which the enclosure includes the wall surface and the structure to which it is attached also serves as a wall surface that reflects sound; and A structure in which the enclosure does not include the wall surface, and instead the structure to which it is attached serves as a wall surface having sound reflections; Any of the above is included in the scope of the present disclosure.

[0034] As described above, when the other side of the speaker is directed toward the user, the one side opposite to the other side is perceived by the user as the “rear side.” In this case, the enclosure may be positioned on the rear side so as to cover at least a portion of the speaker unit. "Covering" here means that the enclosure is installed close to the speaker unit so that it occupies a certain percentage of the total area behind the speaker. This certain percentage can be, for example, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, or it can be 100% or less. The enclosure may be configured to cover at least a portion of one side of the speaker unit, for example: A method of bonding an enclosure to at least a portion of one side of a speaker unit using adhesive, heat fusion, ultrasonic bonding, or the like; A method of joining at least a part of one side of the speaker unit and the enclosure by sewing; A method of simply placing an enclosure on at least a portion of one side of a speaker unit; etc. Of course, another method is to mold the enclosure integrally with the conductive layer of the speaker unit.

[0035] The bending resistance of the enclosure is preferably 300 mm or less, more preferably 250 mm or less, even more preferably 220 mm or less, and particularly preferably 200 mm or less. The bending resistance of the enclosure can be greater than 1 mm, and can be 5 mm or more. Having the bending resistance of the enclosure in this range makes it easy to install a speaker in applications requiring flexibility without impeding that flexibility, and also makes it easy to install a speaker in a complex shape. For the method of measuring the bending resistance, please refer to the contents described in the [Speaker] section.

[0036] The air permeability of the enclosure is preferably 0.1 cm3 / cm2·s or more, more preferably 1 cm3 / cm2·s or more, even more preferably 3 cm3 / cm2·s or more, and particularly preferably 5 cm3 / cm2·s or more. The air permeability of the enclosure can be 2000 cm3 / cm2·s or less, 1500 cm3 / cm2·s or less, or 1000 cm3 / cm2·s or less. With an enclosure's air permeability within this range, sound output from one side of the speaker unit (the side facing the enclosure) is easily transmitted to the enclosure. This makes it easier to attenuate low-frequency sound due to air resistance and the viscous resistance of the structure inside the enclosure, and in this case, it is easier to prevent the sound pressure waves output from one side of the speaker unit and the other side from interfering with and canceling each other. This makes it easier to ensure sufficient sound pressure even at low frequencies. The air permeability is measured using a Frazier tester in accordance with JIS-L-1096, 1018 Air Permeability Test Method (Method A air volume). The air permeability of the enclosure refers to the air permeability in the thickness direction of the enclosure (z-axis direction in the figure).

[0037] The Young's modulus of the enclosure is preferably 1 GPa or less, more preferably 500 MPa or less, and even more preferably 100 MPa or less. The Young's modulus of the enclosure can be greater than 0 MPa and can be 0.01 MPa or more. When the Young's modulus of the enclosure is within this range, the speaker can be easily installed in applications requiring flexibility without impeding that flexibility, and the speaker can be easily installed in complex shapes. The Young's modulus of the enclosure can be measured by referring to the method described in the Examples section.

[0038] The minimum bending radius of the enclosure is preferably 80 mm or less, more preferably 40 mm or less, and even more preferably 20 mm or less. The minimum bending radius of the enclosure can be greater than 5 mm and can be 10 mm or more. Having the minimum bending radius of the enclosure within this range makes it easy to install a speaker in applications requiring flexibility without impeding that flexibility, and also makes it easy to install a speaker in a complex shape. The method for measuring the minimum bending radius of the enclosure may be referred to in the Examples section.

[0039] The thickness of the enclosure is greater than 0 mm, preferably 5 mm or more, more preferably 10 mm or more, and even more preferably 15 mm or more. The thickness of the enclosure is preferably 30 mm or less, more preferably 20 mm or less. Having an enclosure thickness within this range makes it easy to achieve a fabric-like feel, facilitates speaker installation in applications requiring flexibility without impeding that flexibility, and facilitates speaker installation in complex shapes. The "thickness of the enclosure" is represented by the symbol t' in the drawing.

[0040] The enclosure can be at least one selected from the group consisting of woven fabric, knitted fabric, leather, nonwoven fabric, resin sheet, three-dimensional resin model, and three-dimensional knitted fabric, with three-dimensional knitted fabric being preferred. This makes it easier to prevent excessive deformation when touched by a user and ensure sufficient breathability. This makes it easier to attenuate low-frequency sounds due to air resistance and viscous resistance of the structure within the enclosure, which in turn makes it easier to prevent sound pressure waves output from one side of the speaker unit from interfering with and canceling each other. This makes it easier to ensure sufficient sound pressure even at low frequencies.

[0041] "3D knitting" Here, from the same viewpoint as above, the enclosure is preferably a three-dimensional knitted fabric including a surface layer knitted fabric, a back layer knitted fabric, and a connecting yarn connecting the surface layer knitted fabric and the back layer knitted fabric. Such a three-dimensional knitted fabric can be knitted by a warp knitting machine, a circular knitting machine, a flat knitting machine, or the like having two rows of opposing needle beds of 9 to 28 gauge.

[0042] As the connecting yarn for the three-dimensional knitted fabric, a monofilament yarn or a multifilament yarn can be used, and among these, the use of a monofilament yarn is preferred from the viewpoint of keeping the compressive modulus of the seat covering material (surface layer) within an appropriate range and improving compression recovery.

[0043] Examples of the fiber material used for the connecting yarn include fibers of any material, such as polytrimethylene terephthalate fiber, polybutylene terephthalate fiber, polyethylene terephthalate fiber, polyamide fiber, polypropylene fiber, polyvinyl chloride fiber, and polyester-based elastomer fiber. Of these, polyethylene terephthalate fiber is preferred as the fiber material used for the connecting yarn because it is easy to improve recyclability.

[0044] The cross-sectional shape of the fibers used for the connecting yarns may be round, triangular, L-shaped, T-shaped, Y-shaped, W-shaped, octapous, flat, polygonal (e.g., dogbone), multi-lobed, hollow, or irregular. Among these, fibers having a round cross section are preferred from the viewpoint of improving cushioning properties and durability. In addition, from the viewpoint of preventing the unpleasant noise that may be generated when the connecting threads rub against each other when the enclosure is compressed, it is preferable to use a combination of monofilament yarn and multifilament yarn as the connecting thread by interweaving, yarn composite, etc., and to use the multifilament yarn as a buffer material.

[0045] When a monofilament yarn is used as the connecting yarn, any fineness can be used. From the viewpoint of obtaining a soft and elastic feel, a fineness of 50 to 600 decitex is preferred, and more preferably 80 to 500 decitex. The connecting yarn may form loop-shaped stitches in the front knitted fabric and / or the back knitted fabric. The connecting yarn can be hooked into the front knitted fabric and / or the back knitted fabric in an inserted state, a tucked state, or the like. In particular, from the viewpoint of improving the shape stability of the three-dimensional knitted fabric, it is preferable that at least two connecting yarns connect the front knitted fabric and the back knitted fabric in a cross (X-shape) or truss shape, inclined in opposite directions. In both the cross and truss shapes, the two connecting yarns may be composed of different connecting yarns, or one identical connecting yarn may be folded back on the front or back surface to appear as two yarns.

[0046] In three-dimensional knitted fabrics, the fibers used for the knitted fabric of the surface layer and the knitted fabric of the back layer may include any fibers such as polyester fibers such as polyethylene terephthalate fibers, polytrimethylene terephthalate fibers, and polybutylene terephthalate fibers; synthetic fibers such as polyamide fibers, polyacrylic fibers, and polypropylene fibers; natural fibers such as cotton, hemp, and wool; and regenerated fibers such as cupra rayon, viscose rayon, and lyocell.

[0047] The cross-sectional shape of such fibers may be round, triangular, L-shaped, T-shaped, Y-shaped, W-shaped, octapous, flat, polygonal (e.g., dogbone), multilobal, hollow, etc., or may be irregular. The form of such fibers may be any of raw yarns, spun yarns, twisted yarns, false-twisted yarns, air-entangled yarns, bulky yarns such as fluid-jet textured yarns, etc.

[0048] When the connecting yarn includes a monofilament yarn, it is preferable to use a bulky yarn such as a multifilament yarn, false twisted yarn, or spun yarn, from the viewpoint of preventing the connecting yarn from being exposed on the surface of the knitted fabric and thus increasing the coverage factor. In this case, the fineness of the multifilament yarn is usually 150 to 1,000 decitex, and the number of filaments may be set arbitrarily.

[0049] When the fibers used for the surface and back knitted fabrics are multifilaments, the single yarn fineness is preferably 0.5 to 6.0 dtex, more preferably 1.0 to 5.0 dtex, which tends to result in a stronger single yarn.

[0050] In a three-dimensional knitted fabric, the knitted structure of the front layer knitted fabric and the knitted structure of the back layer knitted fabric do not need to be the same, and they may have different knitted structures and / or different elongation properties. However, it is preferable that the standard deviation of the dynamic friction coefficient of the outer surface of the back layer knitted fabric is smaller than the standard deviation of the dynamic friction coefficient of the outer surface of the front layer knitted fabric, as this makes it easier to attach them as a skin material.

[0051] In three-dimensional knitted fabrics, the number of courses / wells in the front layer knitted fabric and the back layer knitted fabric is preferably 18 / 18 to 43 / 28 / 2.54 cm, and more preferably 25 / 20 to 40 / 24 / 2.54 cm. By keeping the number of courses / wells within this range, it becomes possible to easily increase the thermal conductance and heat dissipation value while maintaining the breathability, and it also becomes easy to increase the cool feeling to the touch. To achieve the desired number of courses / wells, it is sufficient to appropriately select the knitting machine gauge, on-machine courses, heat setting conditions, etc.

[0052] A speaker according to one aspect of the present disclosure may include, for example: Pillows, cushions, carpets, hanging scrolls, noren curtains, sofas, futons, blankets, stroller covers, tents, towels, curtains, and other daily necessities, Clothing such as hats, helmets, clothing, scarves, neck gaiters, and neck pillows, Such a speaker can be easily installed in applications requiring flexibility without impeding that flexibility, and can also be easily installed to conform to complex shapes. In other words, such a speaker places fewer restrictions on installation. Furthermore, such a speaker can ensure sufficient sound pressure even at low frequencies.

[0053] [Second embodiment] The aspects provided by the present disclosure are not limited to the above-described first embodiment, and therefore can be modified in various ways within the scope of the gist of the present invention. For example, as shown in FIG. 1(b), the speaker may have a flexible substrate 6 on the outer layer of the enclosure 4 in such a manner that the sound pressure generated by the conductive layers 3, 3' is not completely blocked. Even with this configuration, it is possible to provide a speaker that has few restrictions on installation and can ensure sufficient sound pressure even at low frequencies. [Example]

[0054] Hereinafter, embodiments of the present disclosure will be described with reference to examples and comparative examples. However, the embodiments of the present disclosure are not limited to the following examples. Regarding the examples and comparative examples, various productions, measurements, evaluations, etc. were performed by the following methods. If there are circumstances that make it impossible to carry out the measurements and evaluations using the methods described below, reasonable alternative methods may be used as appropriate.

[0055] [Measurement and Evaluation] (1) Average thickness (mm) For each speaker in the Examples and Comparative Examples, the thickness (t) of the speaker unit and the thickness (t') of the enclosure were measured in accordance with JIS L 1913 Method B. For each speaker unit and enclosure, the thickness was measured at three or more locations under a load of 0.02 kPa, and the average values ​​are shown in the table below.

[0056] (2) Bending resistance (mm) For each speaker in the Examples and Comparative Examples, the bending resistance of the speaker unit and the enclosure was measured in accordance with JIS-L-1096:2010, Method A (45° cantilever method). A 45° cantilever tester was used for the measurements. When the sample had high bending resistance, the inclined surface was extended while maintaining the inclination angle, and the horizontal surface was extended, and then the measurements were taken.

[0057] (3) Air permeability (cm3 / cm2·s) The air permeability of the enclosures of the speakers in the examples and comparative examples was measured in accordance with JIS-L-1096, 1018 air permeability test method (method A air volume) using a Takayama Reed FX3300 Laboair IV air permeability tester.

[0058] (4) Minimum bending radius (mm) For each speaker in the Examples and Comparative Examples, test specimens (50 mm in x-axis length × 200 mm in y-axis length) were left in an environment of 23°C and 50% RH for 48 hours. The test specimens were then wrapped around stainless steel cylinders, and the appearance was visually observed. The minimum radius (minimum bending radius) of the stainless steel cylinder was measured when wrinkles were observed on the test specimen. The stainless steel cylinders were 50 mm high and had radii of 5 to 50 mm at 5 mm intervals. The term "wrinkles" used here refers to lines that appear along the height direction (50 mm direction) of the test piece.

[0059] (5) Young's modulus (MPa) The Young's modulus of each speaker of the example and comparative example was measured in accordance with JIS-K-7127.

[0060] (6) Frequency characteristics A sample speaker (10 cm x 10 cm square) was prepared for each speaker in the Examples and Comparative Examples. In a 4 m x 4 m x 2 m space with a background noise level of 40 dB or less, the sample speaker was placed on a desk with a plastic surface in a manner that ensured there was no gap between the desk and the sample speaker and that the speaker was not deformed, in the comparison between Comparative Example 1 (blank) and Examples 1, 3 to 10, and Comparative Example 2. Furthermore, in the comparison between Comparative Example 1 (blank) and Example 2, the sample speaker was suspended in mid-air. Then, pure tones of 500 Hz, 1000 Hz, and 2000 Hz were generated from the sample speaker. At this time, the sound pressure was measured when the sound was picked up by a microphone at a distance of 1 m from the sample speaker. The sound pressure was measured by setting the input so that the sound pressure at 1000 Hz in Comparative Example 1 (blank) was 55 dB. (Evaluation criteria) The difference between the sound pressure (1) of the speaker without an enclosure (Comparative Example 1) and the sound pressure (2) of the sample speaker was compared, and the difference between the sound pressure (2) and the sound pressure (1) was If the difference is 5dB or more, it is "E" (Excellent). If the difference is greater than 0 dB but less than 5 dB, it is "G" (Good), and If the difference is 0db or lower, it is marked as "P" (Poor). It was evaluated as follows.

[0061] The comparison of the measurements when suspended in air was made by comparing the difference in sound pressure (1) of a speaker without an enclosure (Comparative Example 1) under suspended conditions with the sound pressure (2) of the sample speaker described in Example 2 under suspended conditions, and evaluating them using the same evaluation criteria as for the desk-top conditions.

[0062] (7) Application test For each speaker in the Examples and Comparative Examples, a sample speaker (10 cm x 10 cm square) was prepared. Double-sided tape was applied to the entire back surface of the sample speaker (i.e., the surface facing the enclosure), and the speaker was attached to a stainless steel panel (50 cm x 50 cm). The speaker was visually inspected to determine whether it was properly attached or not. (Evaluation criteria) If stakeout is possible, the result is "OK". If stakeout is not possible, the answer is "Not possible" Here, "failure to attach" means that, for example, wrinkles occurred, causing problems with appearance, or the film was attached with high rigidity but quickly peeled off.

[0063] [Examples and Comparative Examples] Comparative Example 1 A pair of conductive layers was formed using conductive nonwoven fabric (PULSHUT®, 50 μm thick, M.A. Life Materials, Inc.). A 0.3 mm thick, 120 mm square electret film (POREFLON® Membrane, Sumitomo Electric Fine Polymers, part number HP-010-30) made of a fluorine-based polymer was then placed between the pair of conductive layers. An acrylic adhesive was applied in a mesh pattern to at least one of the conductive layer and the dielectric layer. The dielectric layer was then sandwiched between the pair of conductive layers, and the layers were then bonded together, resulting in a conductive layer-dielectric layer-conductive layer structure. Here, wiring was connected to each of the pair of conductive layers, thereby fabricating a speaker.

[0064] Example 1 Using a double raschel knitting machine with 6 reeds, 22 gauge and 6mm hook interval, Two reeds (L2, L3) that form the surface knit fabric supply two parallel twisted polyethylene terephthalate fiber yarns of 167 decitex 48 filaments in a 1-out 1-in (L2) and 1-in 1-out (L3) arrangement. From one reed (L4) forming the connecting portion, 110 decitex polyethylene terephthalate fiber monofilaments are supplied in a 1-out, 1-in arrangement, and further, Two reeds (L5, L6) that form the knitted fabric of the back layer supplied a false twist textured yarn of polyethylene terephthalate fiber with 167 decitex and 48 filaments in an all-in arrangement.

[0065] A three-dimensional knitted fabric was knitted with the knitting structure shown below at a density of 35 courses / 2.54 cm. The resulting fabric was widened by 1% and dry-heat set at 175°C for 1 minute with an overfeed rate of 0%, to produce an enclosure, a three-dimensional knitted fabric that would become the cushion layer. (edited organization) L1:- L2:1011 / 2322 / L3:2322 / 1011 / L4:3410 / 4367 / L5:0001 / 1110 / L6:2234 / 2210 /

[0066] The speaker of Comparative Example 1 was treated as a "flexible electrostatic speaker unit with one side and the other side," and the enclosure prepared above was laminated onto one side of the speaker unit (the side intersecting the bending direction of the conductive layer) to obtain a laminated structure. At this time, an acrylic adhesive was applied in a mesh pattern to the conductive layer of the speaker unit, and the enclosure was adhered to it to produce the speaker.

[0067] Example 2 A speaker was produced in the same manner as in Example 1, except that the knitting structure of the enclosure in Example 1 was changed as follows, thereby reducing the air permeability of the wall surface and reflecting sound. (edited organization) L1:- L2:1011 / 2322 / L3:2322 / 1011 / L4:3410 / 4367 / L5:1110 / 2245 / L6:4445 / 2210 / The frequency response was evaluated using a hanging method, and the rating was "G" at frequencies of 500Hz, 1000Hz, and 2000Hz.

[0068] Example 3 A speaker was produced in the same manner as in Example 1, except that the enclosure was changed to a three-dimensional knitted fabric ("Fusion AKE64334" manufactured by Asahi Kasei Corporation).

[0069] Example 4 A speaker was produced in the same manner as in Example 1, except that the enclosure was changed to a three-dimensional knitted fabric ("Fusion AKE85100" manufactured by Asahi Kasei Corporation).

[0070] Example 5 A speaker was fabricated in the same manner as in Example 1, except that the enclosure was changed to a three-dimensional knitted fabric (Fusion AKE85100 manufactured by Asahi Kasei Corporation) and its thickness was changed to 15 mm.

[0071] Example 6 A speaker was fabricated in the same manner as in Example 1, except that the enclosure was changed to a three-dimensional knitted fabric (Fusion AKE85100 manufactured by Asahi Kasei Corporation) and its thickness was changed to 30 mm.

[0072] Example 7 A speaker was fabricated in the same manner as in Example 1, except that the enclosure was changed to hard urethane (thickness 15 mm).

[0073] Example 8 A speaker was fabricated in the same manner as in Example 1, except that the enclosure was changed to soft urethane (thickness: 40 mm). In the speaker of this example, the thickness of the enclosure was so great that the attachment test could not be properly carried out, and therefore the table below shows "not possible."

[0074] Example 9 A speaker was fabricated in the same manner as in Example 1, except that the enclosure was changed to one made of multiple layers of artificial leather (Dinamica (registered trademark), manufactured by Asahi Kasei Corporation) and the total thickness was changed to 15 mm.

[0075] Comparative Example 2 A speaker was produced in the same manner as in Example 1, except that the enclosure was changed to a PE resin sheet (thickness: 15 mm). Here, the PE resin sheet used was one that had no flexibility.

[0076] Example 10 An acrylic adhesive was applied to the outer layer of the enclosure in Example 4 in a manner (in this case, a mesh shape) that did not completely block the sound pressure generated by the conductive layer. A 100 mm square piece of polyester tricot knit fabric was then attached as a flexible substrate to produce a speaker.

[0077] [Table 1]

[0078] [Table 2]

[0079] As shown in the above table, it was confirmed that the speaker of the embodiment can ensure sufficient sound pressure even at low frequencies. Furthermore, as shown in the table above, the speakers of the examples show good values ​​for "minimum bending radius," "Young's modulus," and "stiffness," confirming that they have excellent flexibility, and in this case, there are few restrictions on installation. [Industrial Applicability]

[0080] A speaker according to one aspect of the present disclosure may include, for example: Pillows, cushions, carpets, hanging scrolls, noren curtains, sofas, futons, blankets, stroller covers, tents, towels, curtains, and other daily necessities, Clothing such as hats, helmets, clothing, scarves, neck gaiters, and neck pillows, etc. Such a speaker has fewer restrictions on installation and can ensure sufficient sound pressure even at low frequencies. This speaker can be easily installed in applications requiring flexibility without impeding that flexibility, and can also be easily installed in complex shapes. In other words, this speaker has fewer installation restrictions. Furthermore, because the enclosure is flexible, it will not collapse even when the speaker is bent or compressed, allowing it to demonstrate stable performance in a variety of applications. [Explanation of symbols]

[0081] 1 speaker 2 Dielectric Layer 3 Pairs of conductive layers 3' Pair of conductive layers 4 Enclosure 5 speaker units 5a One side of the speaker unit 5b Other side of the speaker unit 6 Flexible base material t Speaker unit thickness t' Enclosure thickness

Claims

1. a flexible electrostatic speaker unit having one surface and another surface; a flexible enclosure that covers at least a portion of the one surface of the speaker unit.

2. 2. The speaker according to claim 1, wherein the enclosure has a bending resistance of 300 mm or less.

3. The enclosure has an air permeability of 0.1 cm ３ / cm ２ 3. The loudspeaker according to claim 1, wherein the frequency is equal to or greater than s.

4. 3. The speaker according to claim 1, wherein the enclosure has a Young's modulus of 1 GPa or less.

5. 3. The speaker according to claim 1, wherein the minimum bending radius of the enclosure is 80 mm or less.

6. 3. The speaker according to claim 1, wherein the enclosure is a three-dimensional knitted fabric including a surface layer knitted fabric, a back layer knitted fabric, and a connecting yarn connecting the surface layer knitted fabric and the back layer knitted fabric.

7. 3. The speaker according to claim 1, wherein the average thickness of the enclosure is greater than 0 mm and equal to or less than 30 mm.

8. 3. The speaker unit according to claim 1, wherein a dielectric layer is disposed between a pair of opposing conductive layers, and when an electrical signal is applied to the pair of conductive layers, the pair of conductive layers and the dielectric layer vibrate together to generate sound pressure.

9. The loudspeaker of claim 8 , wherein the conductive layer is made of conductive fibers.

10. The speaker according to claim 8 , wherein the one surface is a surface that intersects with the vibration direction.

11. The speaker according to claim 8 , wherein the one surface and the other surface are both surfaces that intersect with the displacement direction of the conductive layer.

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