Automobile interior material including flexible thin speaker

Abstract

The objective of the present invention is to provide an automobile interior material that includes a flexible thin speaker, is made sufficiently thin, and is flexible, and that can consequently be installed in various parts within an automobile, and to provide an automobile including the automobile interior material. The present invention relates to an automobile interior material including a flexible thin speaker, characterized by having a thickness of 30 mm or less and by generating sound pressure through the vibration of a flexible diaphragm, and an automobile including the automobile interior material, wherein a dielectric layer is disposed between a pair of opposing electrically conductive layers, and an electric signal is applied to the pair of electrically conductive layers to cause the pair of conductive layers and the dielectric layer to vibrate integrally, thereby generating sound pressure.

Description

Automotive interior materials including flexible thin speakers

[0001] The present invention relates to automotive interior materials that include flexible thin speakers.

[0002] As automobile interiors become more and more spacious, there is a growing need to utilize the interior of automobiles as acoustic spaces. To achieve this, it is necessary to reduce noise while the vehicle is running, and to provide passengers with sounds they prefer with a more realistic feel. This has led to improvements in speaker technology for outputting sound. In particular, since speakers must be installed in a limited space inside an automobile, a technology has been proposed that miniaturizes the speaker itself by providing space outside the enclosure, as in Patent Document 1 below.

[0003] Japanese Patent Application Laid-Open No. 2021-111840

[0004] However, the technology described in Patent Document 1 falls within the category of general speakers, and is a funnel-shaped so-called cone type or a spherical dome type, etc., so it cannot be made sufficiently thin, and there is a risk that the lightness and flexibility will be impaired, so it does not fully resolve the limitations on installation space inside a car.

[0005] In view of the above-mentioned prior art, the problem to be solved by the present invention is to provide an automobile interior material including a flexible, thin speaker that is sufficiently thin and flexible so that the interior of the automobile can be used as an acoustic space, and thus can be placed in various spaces within the automobile.

[0006] As a result of extensive research and experimentation to solve the above-mentioned problems, the inventors of the present application unexpectedly discovered that the above-mentioned problems could be solved by using a flexible material in the vibrating part that generates sound pressure, thereby making the speaker itself thinner, and thus completed the present invention.

[0007] That is, the present invention is as follows. [1] An automobile interior material including a flexible, thin speaker having a thickness of 30 mm or less and characterized in that sound pressure is generated by vibration of a flexible diaphragm. [2] An automobile interior material including the flexible, thin speaker according to [1] above, 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 integrally to generate sound pressure. [3] An automobile interior material including the flexible, thin speaker according to [2] above, in which at least one of the pair of conductive layers further comprises an insulating flexible substrate having breathability or stretchability facing the dielectric layer. [4] An automobile interior material including the flexible, thin speaker according to [2] or [3] above, in which at least one of the pair of conductive layers is made of conductive fiber. [5] An automobile interior material including the flexible, thin speaker according to any one of [1] to [4] above, in which frequency characteristics do not change substantially when deformed. [6] An automobile interior material including the flexible, thin speaker having a basis weight of 3,000 g / m ２

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[0015] An automobile interior material comprising the flexible, thin speaker according to any one of [1] to [5], wherein the bending resistance of the flexible, thin speaker is 300 mm or less.

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[11] A vehicle having an automobile interior material including the flexible thin speaker according to any one of [1] to [8] above, which is arranged in at least one of the headrest, seat surface, and seat back of each passenger's seat and is connected to an audio output device by a separate wiring, thereby providing different sounds to each passenger.

[12] A vehicle having an automobile interior material including the flexible thin speaker according to any one of [1] to [8] above, which has a sound output surface and a non-sound output surface, the non-sound output surface being provided with sound insulation of 3 dB or more from 1000 Hz to 2000 Hz.

[13] A vehicle having an automobile interior material including the flexible thin speaker according to any one of [1] to [8] above, wherein the surface farthest from the ears of the person closest to the vehicle when installed as an automobile interior is the non-sound output surface.

[14] A vehicle having an automobile interior material including the flexible thin speaker according to any one of [1] to [8] above, which has a sound directivity ratio of 1.1 or more.

[15] A vehicle having an automobile interior material including the flexible thin speaker according to any one of [1] to [8] above, which is either a front or front left / right speaker arranged at 0° to ±20° to 35° based on a line connecting the main occupant who experiences the sound to the front.

[16] A vehicle having an automobile interior material including the flexible thin speaker according to any one of [1] to [8] above, which are front speakers arranged at 0° based on a line connecting the main occupant who experiences the sound to the front, and front left / right speakers arranged at ±20° to 35° to the left and right of the line connecting the front.

[17] A vehicle having an automobile interior material including the flexible thin speaker according to any one of [1] to [8] above, which are front speakers arranged at 0° based on a line connecting the main occupant who experiences the sound to the front, front left / right speakers arranged at ±20° to 35° to the left and right of the line connecting the front.

[18] An automobile having an automobile interior material comprising the flexible, thin speaker according to any of [1] to [8] above, which are a front speaker arranged at 0° based on a line connecting the main occupant who experiences the sound to the front, front left and right speakers arranged at ±20° to 35° to the left and right of the front based on the line connecting the fronts, two rear speakers arranged at ±90° to 130° rearward based on the line connecting the fronts, and one rear speaker arranged at 180° rearward based on the line connecting the fronts.

[19] An automobile having an automobile interior material comprising the flexible, thin speaker according to any of [1] to [8] above, which are a front speaker arranged at 0° based on a line connecting the main occupant who experiences the sound to the front, front left and right speakers arranged at ±20° to 35° to the left and right of the front based on the line connecting the fronts, two rear speakers arranged at ±90° to 130° rearward based on the line connecting the fronts.

[20] A vehicle having an automobile interior material including the flexible thin speaker according to any one of [1] to [8], arranged in at least one location among the front of a headrest, the sides of the headrest, the back of the headrest, the pillar, the console, and the armrest, so as to occupy 50% or more of the area of ​​each.

[21] A vehicle having an automobile interior material including the flexible thin speaker according to any one of [1] to [8], arranged in at least one location among the seat surface, the seat back, the headliner, the instrument panel, and the door trim, so as to occupy 10% or more of the area of ​​each.

[22] A vehicle having an automobile interior material including the flexible thin speaker according to any one of [1] to [8].

[0008] Because the automotive interior material including the flexible thin speaker of the present invention is thin and lightweight, it can be installed in various locations inside the automobile, and preferably can be placed in at least one location selected from the group consisting of a headrest, a seat cushion, a seat back, a pillar, a headliner, an instrument panel, a door trim, an armrest, and a console.

[0009] 1 is a cross-sectional view of an example of a flexible thin speaker included in an automobile interior material of the present embodiment.

[0010] An embodiment of the present invention will be described in detail below. The automotive interior material of this embodiment includes a flexible, thin speaker having a thickness of 30 mm or less and characterized by generating sound pressure by vibrating a flexible diaphragm. Preferably, the flexible, thin speaker includes a dielectric layer disposed between a pair of opposing conductive layers. An electrical signal is applied to the pair of conductive layers to function as an electrostatic speaker, causing the pair of conductive layers and the dielectric layer to vibrate integrally, generating sound pressure as a flexible diaphragm. The term "thin" as used here refers to a thickness equivalent to that of the skin used in automotive interiors, and is 30 mm or less, preferably 20 mm or less, and more preferably 10 mm or less. As illustrated in FIG. 1 , the thickness (t) refers to the thickness of a dielectric layer disposed between a pair of opposing conductive layers, and, if a breathable or stretchable insulating flexible substrate is further provided facing the dielectric layer, the thickness (t) is the thickness of the combined structure. Having the thickness of the automotive interior material within this range allows for speaker placement without particular restrictions, even in the limited space inside the automobile. Furthermore, while a thinner minimum thickness is preferable, a thickness of 1 mm or more is preferable from the viewpoint of ease of installation in automobile interiors. Furthermore, a larger surface area per unit volume allows for greater sound pressure output. The term "diaphragm" as used herein refers to vibrating materials made of paper, fiber, polymeric materials, metals, or ceramics. The term "automotive interior materials" as used herein includes skin and base materials used in automobile seats, headliners, headrests, consoles, armrests, door trim, carpets, pillars, instrument panels, and the like. Therefore, the term also includes a structure in which a flexible thin speaker is attached to the headrest itself and a cover is wrapped around it as a skin, leaving a gap between the flexible thin speaker and the skin.

[0011] The "flexibility" of the flexible thin speaker included in the automotive interior material of this embodiment refers to flexibility equivalent to that of the skin used in automotive interiors. An example of this flexibility is the bending resistance, which is an index of the flexibility of a fabric. More specifically, the bending resistance 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 is measured using a 45° cantilever tester in accordance with JIS-L-1096:2010, Method A (45° cantilever method). By being within this range, the speaker can be positioned to conform to complex shapes such as curved surfaces inside an automobile. Furthermore, by having the bending resistance within the above range, even if the flexible thin speaker body or its fragments come into contact with passengers in the event of a car collision or other accident, the speaker tends to cause less trauma. The materials that make up the flexible thin speaker will be described later, but by not including hard materials (for example, materials with a bending resistance of more than 300 mm) in the materials that make up the flexible thin speaker or automotive interior materials, traumatic damage tends to be reduced. Traumatic damage here refers to damage to bodily tissues and organs caused by external forces (mechanical, physical, or chemical).

[0012] The flexible thin speaker included in the automotive interior material of this embodiment has a Young's modulus of 10 GPa or less, preferably 5 GPa or less, and more preferably 3 GPa or less. The lower limit of the Young's modulus of the flexible thin speaker is not particularly limited, but can be greater than 0 MPa and can be greater than 0.01 MPa. This range tends to reduce the risk of injury to passengers even if the flexible thin speaker body comes into contact with them. The materials constituting the flexible thin speaker will be described later, but by not including hard materials (e.g., materials with a Young's modulus greater than 10 GPa) in the materials constituting the flexible thin speaker or the automotive interior material, the risk of injury tends to be reduced. In the flexible thin speaker included in the automotive interior material of this embodiment, a dielectric layer is disposed between a pair of opposing conductive layers. By applying an electrical signal to the pair of conductive layers, the pair of conductive layers and the dielectric layer vibrate together, generating sound pressure as a flexible diaphragm.

[0013] The material used for the conductive layer is not particularly limited as long as it can ensure conductivity in the in-plane direction, but conductive fibers are preferred from the viewpoints of ensuring flexibility, breathability, and durability when installed in the vehicle interior. The conductive fibers can be selected from at least one type of fiber from the group consisting of chemical fibers containing highly conductive metals or carbon black, fibers coated with metals or conductive resins, and metal fibers containing metal fibers. Among these, fibers coated with metals such as titanium, gold, silver, copper, and nickel are preferred from the viewpoints of flexibility and light weight. Plating and sputtering are preferred coating methods.

[0014] The Young's modulus of the conductive layer of the flexible, thin speaker included in the automotive interior material of this embodiment is 10 GPa or less, preferably 5 GPa or less, and more preferably 3 GPa or less. The lower limit of the Young's modulus of the conductive layer of the flexible, thin speaker is not particularly limited, but can be greater than 0 MPa and can be 0.01 MPa or more. Having the Young's modulus of the conductive layer within the above range tends to make it possible to appropriately adjust the Young's modulus of the flexible, thin speaker, and also tends to reduce trauma even if the conductive layer falls off the speaker body and comes into contact with an occupant.

[0015] The material used for the dielectric layer is not particularly limited as long as it can ensure flexibility and insulation between the pair of conductive layers, but a flexible polymer material is preferred. Flexible polymer materials include elastomers, thermoplastic resins, thermosetting resins, and rubbers, such as natural rubber, urethane rubber, acrylic rubber, silicone rubber, butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, and other nitrile group-containing rubbers, isoprene rubber, vulcanized rubber, styrene-butadiene rubber, butyl rubber, chlorosulfonated polyethylene rubber, ethylene propylene rubber, and fluorine-based polymers. A dielectric film that is prone to dielectric polarization when sandwiched between positively and negatively charged conductive layers is preferred.

[0016] The Young's modulus of the dielectric layer of the flexible, thin speaker included in the automotive interior material of this embodiment is 5 GPa or less, preferably 1 GPa or less, more preferably 0.1 GPa or less, and particularly preferably 0.01 GPa or less. There is no particular restriction on the lower limit of the Young's modulus of the dielectric layer of the flexible, thin speaker, but it can be greater than 0 MPa and can be 0.01 MPa or more. Having the Young's modulus of the dielectric layer in the above range tends to make it possible to appropriately adjust the Young's modulus of the flexible, thin speaker, and also tends to reduce trauma even if the dielectric layer falls off the speaker body and comes into contact with an occupant.

[0017] In the process of manufacturing the flexible, thin speaker included in the automotive interior material of this embodiment, the structure in which a dielectric layer is sandwiched between a pair of opposing conductive layers can be achieved by preparing the conductive layer and the dielectric layer separately and bonding them together during assembly, bonding them together during the manufacturing process, or by forming a metal layer on the surface of the dielectric layer by sputtering. One method for bonding them together during the manufacturing process is to supply the conductive layer and the dielectric layer from a roll, apply an adhesive to at least one of them, and then pass them through a nip roll to bond them together. Bonding them together during the manufacturing process significantly shortens the cutting and bonding processes and makes it easier to handle more complex shapes.

[0018] At least one of the pair of conductive layers of the flexible thin speaker included in the automotive interior material of this embodiment can have an insulating flexible substrate facing the dielectric layer. The flexible substrate may have breathability, stretchability, and / or flexibility. The "insulating" property here means that the insulating property is sufficient to insulate the electrical signal applied to the conductive layer, and for example, a volume resistivity of 1.0 × 10 ７ The volume resistivity is measured in accordance with JIS-K-6911. When the volume resistivity is in this range, it is possible to prevent an electric signal applied to the conductive layer from leaking from the surface, which can cause electric shock. The term "breathability" as used herein refers to the ability of the sound pressure generated by the vibration of the conductive layer to escape to the outside, and for example, the air permeability is 1 cc / cm ２ / sec or more, preferably 3 cc / cm ２ / sec or more, more preferably 5 cc / cm ２ / sec. The air permeability in the thickness direction is measured using a Frazier-type tester in accordance with JIS-L-1096, 1018 Air Permeability Test Method (Method A air content). The term "elasticity" as used herein refers to, for example, a constant load elongation of 15% or more, preferably 20% or more, and more preferably 25% or more. The constant load elongation is measured in accordance with JIS-L-1096, Method B (constant load method for textiles). Having the elasticity within this range facilitates the installation work when installing the fabric inside a vehicle. The term "flexibility" as used herein refers to, for example, a Young's modulus of 5 GPa or less, preferably 1 GPa or less, more preferably 0.1 GPa or less, and particularly preferably 0.01 GPa or less. The lower limit of the Young's modulus is not particularly limited, but can be greater than 0 MPa and can be 0.01 MPa or more. By having the Young's modulus of the flexible substrate within the above range, the Young's modulus of the flexible thin speaker tends to be able to be appropriately adjusted, and even if the flexible substrate falls off from the speaker body and comes into contact with an occupant, the injury tends to be less.

[0019] The "flexible substrate" referred to here is not particularly limited as long as it can ensure insulation while maintaining breathability. For example, it can be selected from the group consisting of knitted fabrics, woven fabrics, leather, artificial leather, synthetic leather, nonwoven fabrics, resin sheets, rubber sheets, films, breathable waterproof sheets, three-dimensional resin models, and three-dimensional knitted fabrics. Furthermore, the "flexible substrate" does not need to be a single sheet, but can be a laminate of multiple sheets. For example, when installed in a location where compression is expected due to a passenger sitting or touching the seat, a cushioning layer may be inserted to prevent the vibration of the vibrating unit from being hindered even when compressive force is applied. The material that can be used for the inserted layer is not particularly limited as long as it can ensure breathability and cushioning. For example, a urethane foam layer, a three-dimensional resin model, a three-dimensional knitted fabric, etc. can be used. From the viewpoint of ensuring breathability during compression, a three-dimensional knitted fabric is preferably used.

[0020] To prevent electric shock, at least one of the flexible substrates of a flexible thin speaker included in an automotive interior material may have a conductive layer facing the conductive layer, and this conductive layer may be connected to ground. In this case, the conductive layer connected to ground may have an insulating skin layer facing the flexible substrate. This skin layer may be made of any material that is breathable and insulating, but may be selected from the group consisting of knitted fabrics, woven fabrics, leather, artificial leather, synthetic leather, nonwoven fabrics, resin sheets, films, three-dimensional resin models, and three-dimensional knitted fabrics. This allows current to escape through the conductive layer connected to ground, preventing it from flowing to the human body, even if a current leaks beyond the flexible substrate.

[0021] In the process of manufacturing the flexible thin speaker included in the automotive interior material of this embodiment, the structure in which at least one of a pair of conductive layers has a dielectric layer and a flexible substrate facing it can be achieved by preparing the conductive layer, dielectric layer, and flexible substrate separately and bonding them together during assembly, or by bonding them together during the manufacturing process. One method of bonding them together during the manufacturing process is to supply the conductive layer, dielectric layer, and flexible substrate from a roll, apply an adhesive to at least one of the adhesive surfaces of each layer, and then pass them through a nip roll to bond them together. Bonding them together during the manufacturing process can significantly shorten the cutting and bonding processes and also makes it easier to handle more complex shapes.

[0022] The flexible thin speaker included in the automotive interior material of this embodiment may be characterized in that its frequency characteristics do not change substantially when it is deformed. According to this invention, since the electrodes are responsible for generating sound pressure or converting it into an electrical signal, there is no change in frequency characteristics due to deformation, and the speaker has excellent operational stability even when it is deformed in three dimensions.

[0023] The flexible thin speaker included in the automotive interior material of this embodiment has a basis weight of 3000 g / m ２ and preferably 2800 g / m ２ More preferably, 2500 g / m or less. ２With the basis weight in this range, the weight increase is small even when speakers are arranged over a wide area inside the vehicle, which helps prevent an increase in the vehicle weight. Although a lighter weight is preferable, a lower basis weight of 50 g / m is preferable from the viewpoint of workability when installing the material inside the vehicle. ２ The above is more preferable. Furthermore, by having the basis weight of the flexible thin speaker within the above range, even if the flexible thin speaker body or its fragments come into contact with passengers in a car collision, the injury tends to be small. Furthermore, as described below, when an automobile interior material including a flexible thin speaker is attached with an adhesive or pressure-sensitive adhesive, the flexible thin speaker tends to be less likely to fall off in the event of a car collision or the like.

[0024] Automotive interior materials including the flexible thin speaker of this embodiment can be attached to at least one of the seats, headliners, headrests, consoles, armrests, door trim, carpets, and pillars inside an automobile using adhesives or pressure-sensitive adhesives. Because the thin speaker of this embodiment is flexible, it can be easily attached and installed in an automobile.

[0025] The flexible thin speaker included in the automotive interior material of this embodiment generates a noise cancellation signal that is out of phase with environmental noise, thereby enhancing the noise reduction effect inside the automobile. In particular, by placing the automotive interior material including the flexible thin speaker of this embodiment in at least one location among the headrest, seat, seat back, and pillar portion, which are close to the ears of the passengers, the effective noise cancellation range can be significantly expanded.

[0026] The automotive interior material of this embodiment may be characterized by being disposed in at least one of the headrest, seat, and seat back of each passenger's seat, and connected to an audio output device via separate wiring, thereby providing different sounds to each passenger. In this case, it is preferable to have a sound output surface and a non-sound output surface, with the surface furthest from the ears of the person closest to the speaker being installed as the non-sound output surface. Furthermore, it is preferable to provide the non-sound output surface with sound insulation treatment of 3 dB or more, more preferably 5 dB or more, and even more preferably 7 dB or more, from 1000 Hz to 2000 Hz. The sound insulation treatment referred to here is not particularly limited as long as it achieves sound insulation, but methods such as disposing a base material with sound-insulating or sound-absorbing properties, applying sound waves in the opposite phase to the output sound to cancel the output sound, or applying an adhesive or the like to the entire surface to reduce breathability can be applied. When the sound insulation effect of the non-sound output surface is within this range, other passengers will not hear the sound, allowing only one passenger to hear the desired sound.

[0027] The flexible thin speaker included in the automotive interior material of this embodiment may be characterized by a sound directivity ratio of 1.1 or more, preferably 1.2 or more, and more preferably 1.25 or more. With a sound directivity ratio in this range, other passengers will not hear the sound, and only one passenger can hear the desired sound. The "sound directivity ratio" referred to here is a value calculated using the following formula from the sound pressure when a 1000 Hz pure tone is generated from a speaker installed in a specified direction and picked up by a microphone on an arc with a radius of 1 m from the speaker. Sound directivity ratio = P ０° ÷P ９０° (P ０° : Sound pressure (dB) measured in front of the speaker, P ９０° : Sound pressure (dB) measured at a position 90° from the front of the speaker

[0028] The automotive interior material of this embodiment can be installed in locations inside the vehicle that were previously difficult to install, thereby creating a space that enhances the sense of realism of sound by installing multiple speakers. For example, when installed in two locations, the speakers may be installed on the left and right sides in front of the main passenger who will experience the sound, and may be located forward of a line connecting the main passenger and the front, at an angle of ±20° to 35°, preferably ±22° to 33°, and more preferably 25° to 30°. By installing the automotive interior material containing the flexible thin speakers within this range, a sound space can be experienced with a high sense of realism.

[0029] When the automobile interior material of this embodiment is installed in three locations, it may be characterized in that it is installed in front of the main passenger who will experience the sound, and on the left and right sides of the front, and the left and right front speakers are arranged at angles of ±20° to 35°, preferably ±22° to 33°, and more preferably 25° to 30° to the left and right of the front, based on a line connecting the main passenger and the front speakers. By installing the automobile interior material within this range, it is possible to experience a sound space with a high sense of realism.

[0030] When the automobile interior material of this embodiment is installed in five locations, it may be characterized in that it is installed in front of the main occupant who will experience the sound, on the left and right sides of the front, and in two locations behind, with the left and right front speakers positioned at ±20° to 35°, preferably ±22° to 33°, and more preferably 25° to 30°, to the left and right of the front from a line connecting the main occupant and the front speakers as the reference, and the two rear speakers positioned at ±100° to 130°, preferably ±102° to 125°, and more preferably 105° to 120°, to the rear from a line connecting the main occupant and the front speakers as the reference. By installing the automobile interior material within these ranges, a sound space can be experienced with a high sense of realism.

[0031] When the automobile interior material of this embodiment is installed in six locations, it may be characterized in that it is installed in front of the main passenger who will experience the sound, on the left and right sides of the front, and three locations behind, with the left and right front speakers being positioned at angles of ±20° to 35°, preferably ±22° to 33°, and more preferably 25° to 30°, to the left and right of the front from a line connecting the main passenger and the front speakers, the two rear speakers being positioned at angles of ±90° to 130°, preferably ±92° to 125°, and more preferably 95° to 120°, rear from a line connecting the main passenger and the front speakers, and the single rear speaker being positioned 180° rearward from a line connecting the main passenger and the front speakers. By installing the automobile interior material within these ranges, a sound space can be experienced with a high sense of realism.

[0032] When the automobile interior materials of this embodiment are installed in seven locations, they may be installed in four locations: in front of the main passenger who will experience the sound, on the left and right sides of the front, and behind, with the left and right front speakers positioned at angles of ±20° to 35°, preferably ±22° to 33°, and more preferably 25° to 30°, to the left and right of the front from a line connecting the main passenger and the front speakers, the two rear speakers positioned at angles of ±90° to 120°, preferably ±92° to 115°, and more preferably 95° to 110°, rearward from the line connecting the main passenger and the front speakers, and the two rear speakers positioned at angles of ±130° to 150°, preferably ±132° to 147°, and more preferably 135° to 145°, rearward from the line connecting the main passenger and the front speakers. By installing the automobile interior materials within these ranges, a sound space can be experienced with a high sense of realism.

[0033] When the automotive interior material of this embodiment is installed in multiple locations, it may be arranged so that it occupies 50% or more, preferably 55% or more, and more preferably 60% or more of the area of ​​at least one of the headrest, seat cushion, seat back, pillar, headliner, instrument panel, and door trim. By installing the automotive interior material within this range, a highly realistic sound space can be experienced.

[0034] The automotive interior material of this embodiment may be arranged to occupy 10% or more, preferably 12% or more, and more preferably 15% or more of the area of ​​at least one of the seat cushion, seat back, headliner, instrument panel, and door trim. By placing the automotive interior material including the flexible speaker of this embodiment within this area, a highly realistic sound space can be experienced.

[0035] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these. The physical properties in the following examples were measured by the following methods. In principle, the various physical properties of the present invention are measured by the following methods, but if there are circumstances that make it impossible to measure them by the following methods, they can be measured by an appropriate, reasonable alternative method.

[0036] (1) Thickness (mm) Based on JIS L 1913 Method B. The thickness was measured at three or more points under a load of 0.02 kPa, and the average value was calculated.

[0037] (2) Bending Resistance (mm) The bending resistance of a flexible speaker for automobile interior use is measured using a 45° cantilever type testing machine in accordance with JIS-L-1096:2010, Method A (45° cantilever method).

[0038] (3) Air permeability (cc / cm ２ / sec) In accordance with JIS-L-1096, 1018 Air Permeability Test Method (Method A air volume), the air permeability through the flexible substrate is measured using an air permeability tester FX3300 Laboair IV manufactured by Takayama Reed Co., Ltd.

[0039] (4) Stretchability (%) The stretchability of a flexible substrate is measured in accordance with JIS-L-1096, Method B (constant load method for woven fabrics).

[0040] (5) Insulation (Ω·m) The volume resistivity of a flexible substrate is measured by the double ring method in accordance with JIS-K-6911.

[0041] (6) Weight (g / m ２ The basis weight of the flexible thin speaker for automobile interior use is measured in accordance with JIS L 1913.

[0042] (7) Young's modulus (GPa) A tensile test is carried out and the Young's modulus is measured in accordance with JIS-K-7127.

[0043] (8) Sound insulation performance (dB) In accordance with JIS-A-1441, a sample is attached to the opening at the connecting part between the reverberation chamber and the anechoic chamber, and the sound transmission loss from the sound output surface direction to the non-sound output surface direction of the flexible speaker for automobile interiors is measured using an acoustic intensity probe.

[0044] (9) Sound Directivity Ratio (-) In a 4m x 4m space with a background noise level of 40dB or less, a pure tone of 1000Hz is generated from a speaker placed in a specified direction, and the sound is picked up by a microphone on an arc with a radius of 1m from the speaker. This value is calculated using the following formula from the sound pressure. Sound Directivity Ratio = P ０° ÷P ９０° (P ０° : Sound pressure (dB) measured in front of the speaker, P ９０° : Sound pressure (dB) measured at a position 90° from the front of the speaker

[0045] (10) Installation inside a car Whether or not the tape could be installed inside a car while applying stress was judged as "OK" or "NO."

[0046] (11) Sound frequency characteristics Pure tones of 500 Hz, 1000 Hz, and 2000 Hz were generated from a speaker placed in a 4 m x 4 m space with a background noise level of 40 dB or less, and the ratio of the sound pressure measured by a microphone at a distance of 1 m from the speaker to the sound pressure measured by the same procedure when the speaker was placed inside a parked car with a background noise level of 40 dB or less was deemed to have passed the test.

[0047] (12) Appearance Eight monitors were asked to evaluate whether they felt a sense of unity between the speakers and the interior of the vehicle using the following three-point evaluation standard, and the most frequent value was used as the evaluation result. 3: A sense of unity is felt 2: Can't say either way 1: No sense of unity is felt

[0048] (13) Noise reduction effect When the environmental noise was measured while the car was running, and at the same time a noise canceling signal in the opposite phase to the environmental noise was output, the monitor inside the car was asked to perform a sensory evaluation using the following five-point scale to see if they felt any noise reduction, with the most frequent value being the evaluation result. The number of monitors was eight. 5: Significant noise reduction effect felt 4: Noise reduction effect felt 3: Noise reduction effect felt to some extent 2: No noise reduction effect felt at all 1: No noise reduction effect felt at all

[0049] (14) Sound space design for each passenger A passenger who is to experience the sound is seated in the passenger seat, and a monitor is seated in the rear seat directly behind the passenger. When a pure tone of 1000 Hz is played at the ear of the passenger who is to experience the sound at a sound pressure of 60 dB, the monitor is asked to perform a sensory evaluation using the following five-point evaluation standard to determine whether or not they sensed sound leakage, and the most frequent value is used as the evaluation result. The number of monitors was eight. 5: No sound leakage is sensed at all 4: Almost no sound leakage is sensed 3: Very little sound leakage is sensed 2: Some sound leakage is sensed 1: Sound leakage is sensed

[0050] (15) Realism A monitor who was to experience the sound was seated in the center of the back seat, and when a 1000 Hz pure tone was played so that the sound pressure at the ear was 60 dB, whether the monitor felt any sound leakage was evaluated using the following five-point evaluation standard, and the most frequent value was used as the evaluation result. The number of monitors was eight. 5: Feels a great sense of realism 4: Feels a sense of realism 3: Feels a slight sense of realism 2: Feels almost no sense of realism 1: Does not feel a sense of realism at all

[0051] Example 1 A pair of conductive layers was formed using a 0.5 mm thick, 100 mm square knitted fabric made of conductive fibers with a nylon core and silver-plated surfaces. A 0.3 mm thick, 120 mm square electret film made of a fluorine-based polymer (Poreflon (registered trademark) membrane, manufactured by Sumitomo Electric Fine Polymer Co., Ltd., product number HP-010-30) was sandwiched between the pair of conductive layers, and each layer was bonded by applying an acrylic adhesive in a mesh pattern, resulting in a conductive layer-dielectric layer-conductive layer structure. At this time, wiring was connected to each of the pair of conductive layers. Furthermore, an acrylic adhesive was applied in a mesh pattern to the outer layer of the conductive layer to allow sound pressure generated in the conductive layer to pass through. A 150 mm square polyester tricot knit was then attached to this as a flexible substrate, resulting in an automotive interior material including a flexible speaker. A 150mm square piece of car headliner skin was cut out, and instead, a car interior material containing a flexible thin speaker was attached. An electrical signal was applied through wiring to output a 1000Hz pure tone. Sound was output without any problems. Furthermore, the thickness did not protrude from the conventional headliner, and the interior appearance of the car was maintained. The results are shown in Table 1 below.

[0052] [Example 2] As a flexible substrate, artificial leather (Dinamica (registered trademark), manufactured by Asahi Kasei Corporation, basis weight: 290 g / m ２ An automobile interior material containing a flexible speaker was obtained in the same manner as in Example 1, except that the dielectric layer was changed to a 0.25 mm thick sheet made of natural rubber. A 150 mm square piece of automobile headrest skin was cut, and the automobile interior material containing the flexible thin speaker was attached instead. An electrical signal was applied via wiring to output a 1000 Hz pure tone, and sound was output without any problems. Furthermore, the thickness did not protrude from the conventional headrest, and the interior appearance of the vehicle was maintained. The results are shown in Table 1 below.

[0053] Example 3: An automobile interior material including a flexible speaker was obtained in the same manner as in Example 1, except that the flexible substrate was changed to a three-dimensional knitted fabric. Using a double Russell knitting machine equipped with six reeds and having a 22 gauge and a 6 mm shuttle spacing, two strands of 167 dtex, 48 filament polyethylene terephthalate false twisted yarn were fed in a 1-out-1-in (L2) and 1-in-1-out (L3) arrangement from the two reeds (L2, L3) that formed the knitted fabric for the front layer, a 110 dtex polyethylene terephthalate monofilament was fed in a 1-out-1-in arrangement from the one reed (L4) that formed the connecting portion, and a 167 dtex, 48 filament polyethylene terephthalate false twisted yarn was fed in an all-in arrangement from the two reeds (L5, L6) that formed the knitted fabric for the back layer. A three-dimensional knit fabric was knitted with the knit structure shown below at a density of 35 courses / 2.54 cm. The resulting knit fabric was widened by 1% and dry-heat set at 175°C for 1 minute with an overfeed rate of 0%, resulting in a three-dimensional knit fabric. (Knit structure) L1: - L2: 1011 / 2322 / L3: 2322 / 1011 / L4: 3410 / 4367 / L5: 0001 / 1110 / L6: 2234 / 2210 / A 150mm square piece of automotive seatback skin was cut, and an automotive interior material containing a flexible speaker was attached in its place. An electrical signal was applied via wiring to output a 1000 Hz pure tone. Sound output was successful. Furthermore, the thickness did not protrude from the conventional seatback, maintaining the interior appearance of the vehicle. The results are shown in Table 1 below.

[0054] Example 4 An automobile interior material including a flexible speaker was obtained in the same manner as in Example 1, except that a thin silver film was formed on both sides of the dielectric layer by a two-pole sputtering method, resulting in a 120 mm square conductive layer-dielectric layer-conductive layer structure. A 150 mm square piece of automobile headrest skin was cut out, and an automobile interior material including a flexible thin speaker was attached instead. An electrical signal was applied via wiring to output a 1000 Hz pure tone, and sound output was possible without any problems. Furthermore, the thickness did not protrude from the conventional headrest, and the interior appearance of the vehicle was maintained. The results are shown in Table 1 below.

[0055] Example 5 Using the same conductive layer, dielectric layer, and flexible substrate as those used in Example 1, an acrylic adhesive was applied in stripes to both sides of an electret film fed from a roll. A silver conductive fiber knit was separately fed from rolls on both the top and bottom sides and wound through a nip roll to obtain a conductive layer-dielectric layer-conductive layer structure. The structure was then fed from a roll, and an acrylic adhesive was applied in stripes to both sides. A polyester tricot knit was then fed from both the top and bottom sides and wound through a nip roll to obtain an automotive interior material including a flexible speaker. This automotive interior material was cut into 150 mm square pieces, and wiring was connected to each of the pair of conductive layers. A 150 mm square piece of automotive headrest skin was cut, and an automotive interior material including a flexible thin speaker was attached instead. An electrical signal was applied through wiring to output a 1000 Hz pure tone. Sound output was successful. Furthermore, the thickness did not increase compared to conventional headrests, preserving the interior appearance of the vehicle. The results are shown in Table 1 below.

[0056] [Example 6] An automobile interior material including the flexible speaker obtained in Example 1 was installed on the surface of a headrest, and while the vehicle was traveling on a flat road at a speed of 70 km / h, a waveform in opposite phase to noise picked up by an environmental noise pickup microphone installed nearby was output from the flexible speaker. The results are shown in Table 1 below.

[0057] Example 7 An automobile interior material including a flexible, thin speaker was obtained in the same manner as in Example 1, except that one of the flexible substrates arranged to sandwich a pair of conductive layers was changed to a sound-insulating sheet made of a polyolefin-based material. This automobile interior material was placed on the headrest skin with the sound-insulating sheet surface facing away from the ears of the passenger, and a pure tone of 1000 Hz was generated. The results are shown in Table 1 below.

[0058] Example 8 An automobile interior material including a flexible speaker was obtained in the same manner as in Example 1, except that one of the flexible substrates arranged so as to sandwich the pair of conductive layers was coated entirely with an acrylic adhesive. This automobile interior material including a flexible, thin speaker was placed on the headrest surface of a vehicle so that the surface entirely coated with the acrylic adhesive was the side farthest from the ears, and a pure tone of 1000 Hz was generated. The results are shown in Table 1 below.

[0059] [Example 9] The automobile interior material including the flexible speaker obtained in Example 1 was placed on the back of the driver's seat and the passenger seat so that the angle when viewed from the rear center seat was ±30°, and a pure tone of 1000 Hz was generated. The sense of realism felt by the passenger sitting in the rear center seat was evaluated, and the results are shown in Table 1 below.

[0060] Example 10 Automotive interior materials containing the flexible thin speakers obtained in Example 1 were placed in three locations: the center console and the backs of the driver's seat and passenger seat, so that the angles, as viewed from the rear center seat, were 0° for the center console and ±30° for the driver's seat and passenger seat, respectively. A pure tone of 1000 Hz was generated, and the sense of realism felt by the passenger sitting in the rear center seat was evaluated. The results are shown in Table 2 below.

[0061] Example 11 Automotive interior materials containing the flexible thin speakers obtained in Example 1 were placed in five locations: the center console, the backs of the driver's seat and passenger seat, and two C-pillars, so that the angles as seen from the rear center seat were 0° for the center console, ±30° for the driver's seat and passenger seat, and ±110° for the two C-pillars. A pure tone of 1000 Hz was generated, and the sense of realism felt by the passenger sitting in the rear center seat was evaluated. The results are shown in Table 2 below.

[0062] Example 12 Automotive interior materials containing the flexible thin speakers obtained in Example 1 were placed in a total of six locations: the center console, the backs of the driver's seat and passenger seat, two C-pillars, and the rear gate, so that the angles as seen from the rear center seat were 0° for the center console, ±30° for the driver's seat and passenger seat, ±100° for the two C-pillars, and 180° for the rear gate. A pure tone of 1000 Hz was generated, and the sense of realism felt by the passenger sitting in the rear center seat was evaluated. The results are shown in Table 2 below.

[0063] Example 13 Automotive interior materials containing the flexible thin speakers obtained in Example 1 were placed in seven locations, including the center console, the backs of the driver's seat and passenger seat, two C-pillars, and two D-pillars, so that the angles as seen from the rear center seat were 0° for the center console, ±30° for the driver's seat and passenger seat, ±100° for the two C-pillars, and ±140° for the two D-pillars. A pure tone of 1000 Hz was generated, and the sense of realism felt by the passenger sitting in the rear center seat was evaluated. The results are shown in Table 2 below.

[0064] [Example 14] An automobile interior material including the flexible thin speaker obtained in Example 1 was installed so as to cover 50% of the area of ​​the headliner, and when a pure tone of 1000 Hz was generated, the sense of realism felt by a passenger sitting in the rear center seat was evaluated. The results are shown in Table 2 below.

[0065] Comparative Example 1 An automobile interior material containing a flexible speaker was obtained in the same manner as in Example 1, except that the flexible substrate was changed to a tricot knit fabric with polyurethane foam. A 150 mm square piece of automobile headrest skin was cut, and the automobile interior material containing the flexible speaker was attached instead. An electrical signal was applied via wiring to output a 1000 Hz pure tone. However, the thickness was too large, and the sense of unity with the interior was impaired. Furthermore, due to low flexibility and stretchability, it could not be stretched when installed inside the automobile, and conformability could not be ensured. Furthermore, due to the low breathability of the flexible substrate, the frequency characteristics of high-frequency sound were impaired. The results are shown in Table 2 below.

[0066] [Example 15] An automobile interior material including the flexible thin speaker obtained in Example 1 was installed in an air conditioner outlet of an instrument panel, and while driving on a flat road at a speed of 70 km / h, a waveform in opposite phase to noise picked up by an environmental noise pickup microphone installed nearby was output from the flexible speaker. The results are shown in Table 2 below.

[0067] Example 16 An automobile interior material including a flexible, thin speaker was obtained in the same manner as in Example 1, except that one of the flexible substrates arranged to sandwich a pair of conductive layers was changed to a highly breathable polyester knit. This automobile interior material was placed on the headrest skin so that the highly breathable polyester knit surface was the side farthest from the ears of the passenger, and a pure tone of 1000 Hz was generated. The results are shown in Table 2 below.

[0068] [Comparative Example 2] A 1000 Hz pure tone was generated from an existing in-vehicle speaker. The speaker positions, as viewed from the rear center seat, were ±40° at the front door trim and ±80° at the rear door trim. The passenger sitting in the rear center seat was evaluated for the sense of realism, and the result was "1."

[0069] Example 17 An automobile interior material including the flexible thin speaker obtained in Example 1 was installed to cover 40% of the area of ​​the headliner, and a pure tone of 1000 Hz was generated. The sense of realism felt by a passenger sitting in the rear center seat was evaluated, and the results are shown in Table 2 below.

[0070]

[0071]

[0072] Automotive interior materials including the flexible thin speaker of the present invention are sufficiently thin and flexible, and therefore can be suitably used in parts inside automobiles such as seats, headliners, headrests, consoles, armrests, door trims, and carpets.

[0073] 1 Automotive interior material including a flexible thin speaker 2 Dielectric layer 3 Pair of conductive layers 3' Pair of conductive layers 4 Breathable or stretchable insulating flexible substrate 4' Breathable or stretchable insulating flexible substrate t Thickness of automotive interior material including a flexible thin speaker 5 Sound insulation processing 6 Flexible diaphragm

Claims

1. An automobile interior material including a flexible thin speaker having a thickness of 30 mm or less and generating sound pressure by vibrating a flexible diaphragm.

2. An automobile interior material including the flexible thin speaker according to claim 1, 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.

3. The automobile interior material including the flexible thin speaker according to claim 2, wherein at least one of the pair of conductive layers further comprises an insulating flexible substrate having breathability or elasticity on the surface opposite the dielectric layer.

4. An automobile interior material including a flexible thin speaker according to claim 2 or 3, wherein at least one of the pair of conductive layers is made of conductive fibers.

5. An automobile interior material comprising the flexible thin speaker according to claim 1 or 2, the frequency characteristics of which do not change substantially when the speaker is deformed.

6. The flexible thin speaker has a basis weight of 3000 g / m ２ 3. An automobile interior material comprising the flexible thin speaker according to claim 1 or 2, which is as follows:

7. An automobile interior material including the flexible thin speaker according to claim 1 or 2, wherein the bending resistance of the flexible thin speaker is 300 mm or less.

8. An automobile interior material comprising the flexible thin speaker according to claim 1 or 2, wherein the Young's modulus of the flexible thin speaker is 10 GPa or less.

9. An automobile having an automobile interior material including a flexible, thin speaker, in which the automobile interior material including the flexible, thin speaker according to claim 1 or 2 is attached by an adhesive or pressure-sensitive adhesive to at least one of the seats, headliners, headrests, consoles, armrests, door trim, carpets, and pillar portions inside the automobile.

10. A vehicle having an automobile interior material including the flexible thin speaker according to claim 1 or 2, which is arranged in at least one of a headrest, a seat, a seat back, and a pillar portion within the vehicle, and which generates a noise cancellation signal in anti-phase with environmental noise.

11. A vehicle having an automobile interior material including the flexible thin speaker according to claim 1 or 2, which is arranged in at least one of the headrest, seat surface, and seat back of the seat of each passenger, and which is connected to an audio output device by a different wiring, thereby providing different sounds to each passenger.

12. A thin speaker for an automobile having an automobile interior material including the flexible thin speaker according to claim 1 or 2, which has a sound output surface and a non-sound output surface, and the non-sound output surface is provided with sound insulation treatment of 3 dB or more for frequencies from 1000 Hz to 2000 Hz.

13. A vehicle having an automobile interior material including the flexible thin speaker according to claim 1 or 2, the surface farthest from the ears of the person closest to the vehicle being installed as an automobile interior material being a non-sound output surface.

14. An automobile having an automobile interior material including the flexible thin speaker according to claim 1 or 2, the directivity ratio of the sound being 1.1 or more.

15. An automobile having an automobile interior material including the flexible thin speaker according to claim 1 or 2, which is either a front or front left / right speaker arranged at 0° or ±20° to 35° with respect to a line connecting the main occupant experiencing the sound and the front.

16. An automobile having automobile interior material including a flexible thin speaker according to claim 1 or 2, the flexible thin speaker being a front speaker arranged at 0° with respect to a line connecting the main occupant experiencing the sound and the front of the automobile, and front left and right speakers arranged at ±20° to 35° to the left and right of the line connecting the front of the automobile.

17. An automobile having automobile interior materials including the flexible thin speaker according to claim 1 or 2, the front speakers being arranged at 0° with respect to a line connecting the main occupant who experiences the sound and the front, the front left and right speakers being arranged at ±20° to 35° to the left and right of the front with respect to the line connecting the front, and two rear speakers being arranged at ±100° to 130° rearward with respect to the line connecting the front.

18. An automobile having automobile interior materials including the flexible thin speaker according to claim 1 or 2, which are a front speaker arranged at 0° based on a line connecting the main occupant who experiences the sound and the front, front left and right speakers arranged at ±20° to 35° to the left and right of the front based on the line connecting the fronts, two rear speakers arranged at ±90° to 130° rearward based on the line connecting the fronts, and one rear speaker arranged 180° rearward based on the line connecting the fronts.

19. An automobile having an automobile interior material including a flexible thin speaker as described in claim 1 or 2, which is a front speaker arranged at 0° based on a line connecting the main occupant who experiences the sound and the front, front left and right speakers arranged at ±20° to 35° to the left and right of the front based on the line connecting the fronts, two rear speakers arranged at ±90° to 120° rearward based on the line connecting the fronts, and two rear speakers arranged at ±130° to 150° rearward based on the line connecting the fronts.

20. A vehicle having an automobile interior material including the flexible thin speaker according to claim 1 or 2, which is arranged in at least one or more of the front surface of a headrest, the side surface of a headrest, the back surface of a headrest, a pillar, a console, and an armrest, so as to occupy 50% or more of the area of ​​each of the following:

21. An automobile having an automobile interior material including the flexible thin speaker according to claim 1 or 2, which is arranged in at least one or more of the seat cushion, seat back, headliner, instrument panel, and door trim so as to occupy an area of ​​10% or more of the respective areas.

22. An automobile having an automobile interior material including the flexible thin speaker according to claim 1 or 2.

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