Sound output device, automobile glass module, sound output method, and program

Abstract

This sound output device comprises: a glass plate; a plurality of sound output units provided on the glass plate; and a control device that controls the plurality of sound output units. The control device generates, on the basis of a first signal, a first anti-noise signal for causing a first sound output unit among the plurality of sound output units to output first anti-noise, and outputs the first anti-noise signal to the first sound output unit. The control device also generates a second anti-noise signal for causing a second sound output unit among the plurality of sound output units to output second anti-noise on the basis of a second signal having the frequency characteristics different from those of the first signal, and outputs the second anti-noise signal to the second sound output unit.

Description

Sound output device, automobile glass module, sound output method, and program

[0001] The present disclosure relates to an audio output device, an automobile glass module, an audio output method, and a program.

[0002] Conventionally, a sound insulation device has been known that includes an outdoor sound detection unit that outputs a reference signal corresponding to outdoor noise, a plurality of vibration output units provided in a glass plate structure, and a control unit that outputs drive signals to the plurality of vibration output units based on the reference signal (see, for example, WO 2022 / 158542). This sound insulation device is said to be able to effectively silence a room by blocking noise in a wide frequency band, including high frequency bands.

[0003] However, in the above-mentioned conventional technology, a drive signal is generated based on a common reference signal output from an outdoor sound detection unit, and multiple vibration output units are driven based on the drive signal. Therefore, sounds having similar frequency characteristics are emitted from the glass plate structure by the multiple vibration output units, which may result in an insufficient noise cancellation effect.

[0004] The present disclosure aims to provide an acoustic output device, an automobile glass module, an acoustic output method, and a program that can enhance the noise cancellation effect compared to conventional techniques.

[0005] A first aspect of the present disclosure is an acoustic output device comprising: a glass plate; a plurality of acoustic output units provided on the glass plate; and a control device that controls the plurality of acoustic output units, wherein the control device generates a first anti-noise signal based on a first signal, for causing a first acoustic output unit of the plurality of acoustic output units to output a first anti-noise signal, outputs the first anti-noise signal to the first acoustic output unit, generates a second anti-noise signal based on a second signal having frequency characteristics different from those of the first signal, for causing a second acoustic output unit of the plurality of acoustic output units to output a second anti-noise signal, and outputs the second anti-noise signal to the second acoustic output unit.

[0006] A second aspect of the present disclosure is an automotive glass module comprising a glass plate and a plurality of acoustic output units provided on the glass plate, wherein a first acoustic output unit among the plurality of acoustic output units outputs a first anti-noise, and a second acoustic output unit among the plurality of acoustic output units outputs a second anti-noise having a frequency characteristic different from that of the first anti-noise.

[0007] A third aspect of the present disclosure is an acoustic output method including: generating a first anti-noise signal based on a first signal, for causing a first acoustic output unit among a plurality of acoustic output units provided on a glass plate to output a first anti-noise signal; outputting the first anti-noise signal to the first acoustic output unit; generating a second anti-noise signal based on a second signal having frequency characteristics different from those of the first signal, for causing a second acoustic output unit among the plurality of acoustic output units to output a second anti-noise signal; and outputting the second anti-noise signal to the second acoustic output unit.

[0008] A fourth aspect of the present disclosure is a program for causing a computer to execute a process including generating a first anti-noise signal based on a first signal, for causing a first acoustic output unit among a plurality of acoustic output units provided on a glass plate to output a first anti-noise signal, and outputting the first anti-noise signal to the first acoustic output unit; generating a second anti-noise signal based on a second signal having frequency characteristics different from those of the first signal, for causing a second acoustic output unit among the plurality of acoustic output units to output a second anti-noise signal, and outputting the second anti-noise signal to the second acoustic output unit.

[0009] According to the present disclosure, there are provided an acoustic output device, an automobile glass module, an acoustic output method, and a program that can enhance the effect of canceling noise compared to conventional techniques.

[0010] 1 is a plan view showing an example of a vehicle to which a sound output device is applied. FIG. 2 is a side view showing an example of a glass vibration module. FIG. 3 is an enlarged cross-sectional view of a main portion showing an example of a glass vibration module. FIG. 4 is a block diagram showing an example of the configuration of a sound output device according to a first embodiment. FIG. 5 is a graph showing an example of the relationship between coherence factors and frequencies for a first vibration sensor and a second vibration sensor. FIG. 6 is a graph showing a first example of noise in an indoor space detected by a microphone. FIG. 7 is a graph showing a second example of noise in an indoor space detected by a microphone. FIG. 8 is a graph showing an example of the relationship between coherence factors and frequencies. FIG. 9 is a block diagram showing an example of the configuration of a sound output device according to a second embodiment. FIG. 10 is a block diagram showing an example of the configuration of a sound output device according to a third embodiment. FIG. 11 is a block diagram showing an example of the configuration of a control device according to a fourth embodiment. FIG. 12 is a block diagram showing an example of the operation of the control device according to the fourth embodiment. FIG. 13 is a flowchart showing an example of the flow of anti-noise signal output processing according to the fourth embodiment. FIG. 14 is a flowchart showing an example of the flow of cancellation coefficient update processing according to the fourth embodiment. FIG. 15 is a flowchart showing an example of the flow of recording processing according to the fourth embodiment. FIG. 16 is a flowchart showing an example of the flow of estimation processing according to the fourth embodiment. FIG. 17 is a flowchart showing an example of the flow of filter coefficient update processing according to the fourth embodiment. FIG. 18 is a block diagram showing a modified example of the operation of a control device according to the fourth embodiment. FIG. 19 is a block diagram showing an example of the configuration of a control device according to a fifth embodiment. FIG. 19 is a block diagram showing an example of the operation of a control device according to the fifth embodiment. FIG. 10 is a flowchart showing an example of the flow of a recording process according to the fifth embodiment. FIG. 11 is a block diagram showing an example of the operation of a control device according to the sixth embodiment. FIG. 12 is a flowchart showing an example of the flow of an anti-noise signal output process according to the sixth embodiment. FIG. 13 is a flowchart showing an example of the flow of a cancellation coefficient update process according to the sixth embodiment. FIG. 14 is a block diagram showing an example of the operation of a control device according to the seventh embodiment. FIG. 15 is a flowchart showing an example of the flow of an anti-noise signal output process according to the seventh embodiment. FIG. 16 is a block diagram showing an example of the operation of a control device according to the eighth embodiment.13 is a flowchart showing an example of the flow of anti-noise signal output processing according to the eighth embodiment.

[0011] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0012] (Configuration of a Vehicle as an Example of an Application Target) Before describing the sound output device 50, the configuration of a vehicle as an example of an application target of the sound output device 50 will be described. FIG. 1 shows a vehicle 10 as an application target. The vehicle 10 is, as an example, a passenger car. Note that the vehicle 10 may be a passenger car, a bus, a freight vehicle, a special-purpose vehicle, or construction machinery. The vehicle 10 may also be an internal combustion engine vehicle using an internal combustion engine as a drive source, a hybrid vehicle using an internal combustion engine and a rotating electric machine as a drive source, or an electric vehicle using a rotating electric machine as a drive source. Furthermore, in addition to the vehicle 10, moving objects such as aircraft, helicopters, drones, or ships may also be application targets. Below, an example will be described in which the vehicle 10 is a passenger car (particularly, a sedan-type vehicle with four doors).

[0013] The vehicle 10 includes an interior space 12 and multiple panes of glass 14. Hereinafter, the space within the interior space 12 will be referred to as the interior space, and the space outside the interior space will be referred to as the exterior space. The multiple panes of glass 14 are located between the interior space and the exterior space, and separate the interior space from the exterior space. The multiple panes of glass 14 include a windshield 14A, front side panes (front door panes) 14B, rear side panes (rear door panes) 14C, a rear pane 14D, a front bench pane 14E, and a roof pane 14F. The vehicle 10 may also include other panes of glass, such as rear quarter panes.

[0014] (Configuration of Glass Vibration Module 1) Next, the configuration of the glass vibration module 1 applicable to multiple glasses 14 installed in the vehicle 10 will be described. FIG. 2 shows one of the glass vibration modules 1 applied to multiple glasses 14 installed in the vehicle 10. The glass vibration module 1 shown in FIG. 2 is configured as a front side glass 14B, as an example. The glass vibration module 1 includes a glass plate 2 and multiple sound output units 3. The glass vibration module 1 is an example of an "automotive glass module" in the present disclosure.

[0015] The glass plate 2 may be made of a single glass plate or may be made of laminated glass. The laminated glass may have two or more glass plates 2. The glass plate 2 may be made of inorganic glass or organic glass. Examples of organic glass include PMMA (Polymethyl methacrylate)-based resin, PC (Polycarbonate)-based resin, PS (Polystyrene)-based resin, PET (Polyethylene terephthalate)-based resin, PVC (Polyvinyl chloride)-based resin, and cellulose-based resin.

[0016] When the glass plate 2 is made of inorganic glass, the glass plate 2 may be untempered glass or tempered glass. Untempered glass is glass obtained by forming molten glass into a plate shape and slowly cooling it. Tempered glass is glass in which a compressive stress layer is formed on the surface of untempered glass, and may be either air-cooled tempered glass or chemically tempered glass. Furthermore, the glass plate 2 may be a glass plate 2 that absorbs ultraviolet or infrared rays. The glass plate 2 may be transparent or may be colored to an extent that does not impair transparency.

[0017] The multiple sound output units 3 are provided on the glass plate 2. The multiple sound output units 3 are components that vibrate the glass plate 2 to output sound from the glass plate 2. The multiple sound output units 3 may be provided at any position on the glass plate 2. However, for example, if regulations restrict the installation position on the glass plate 2, the multiple sound output units 3 are installed at positions that satisfy the regulations. Furthermore, if it is necessary to ensure visibility through the glass plate 2, the multiple sound output units 3 are installed at positions that ensure visibility through the glass plate 2. In the example shown in FIG. 2 , the multiple sound output units 3 are installed at the lower part of the glass plate 2. The lower part of the glass plate 2 is a portion that is hidden by, for example, a door panel and interior components.

[0018] Any number of sound output units 3 may be installed on one glass plate 2. The sound output units 3 may have the same configuration or different configurations. In the example shown in FIG. 2 , the number of sound output units 3 is two. Below, an example in which the number of sound output units 3 is two will be described. When it is necessary to distinguish between the two sound output units 3, one of the two sound output units 3 will be referred to as the "first sound output unit 3A" and the other of the two sound output units 3 will be referred to as the "second sound output unit 3B."

[0019] (Configuration of Sound Output Unit 3) Next, a description will be given of the configuration of the sound output unit 3. As shown in Fig. 3, the sound output unit 3 has a vibrator 4, a connecting member 6, a mount member 7, and a resin layer 8.

[0020] A mount member 7 is fixed to one main surface of the glass plate 2 via a resin layer 8. The resin layer 8 may be an adhesive or a pressure-sensitive adhesive. The pressure-sensitive adhesive may be an adhesive tape. A vibrator 4 is fixed to the surface of the mount member 7 opposite the glass plate 2 via a connecting member 6. The connecting member 6, like the resin layer 8, may be an adhesive or a pressure-sensitive adhesive. Note that the mount member 7 and the resin layer 8 may be omitted, and the vibrator 4 may be fixed to one main surface of the glass plate 2 via the connecting member 6. Alternatively, the vibrator 4 may be mechanically fastened to the connecting member 6 by a fastening part such as a screw.

[0021] The vibrator 4 is connected to a control device 30 (described later) and vibrates the glass plate 2 in response to an anti-noise signal input from the control device 30. An example of the vibrator 4 is a voice coil actuator. The voice coil actuator has a coil (not shown) and a magnetic circuit (not shown). One of the coil and the magnetic circuit is fixed to a mount member 7 via a connection member 6, and the other is arranged so as to be movable relative to the mount member 7. When a current flows through the coil in response to the anti-noise signal, vibrations are output due to the interaction between the coil and the magnetic circuit, and the vibrations of the vibrator 4 are transmitted to the glass plate 2 via the mount member 7. This causes the glass plate 2 to vibrate, and sound is output from the glass vibration module 1.

[0022] The actuator used in the vibrator 4 can be selected from any type of actuator that can vibrate the glass plate 2, such as a voice coil actuator or a piezoelectric actuator. Furthermore, the device that vibrates the glass plate 2 may be something other than an actuator, as long as it can output sound by vibrating the glass plate 2.

[0023] (Configuration of the sound output device 50 according to the first embodiment) Next, the configuration of the sound output device 50 according to the first embodiment will be described. As shown in Fig. 4, the sound output device 50 according to the first embodiment is applied to a vehicle 10. The sound output device 50 includes an information acquisition device group 20, a plurality of vibration sensors 22, a control device 30, a plurality of glass vibration modules 1, a microphone 24, and a recording device 26.

[0024] The information acquisition device group 20, the plurality of vibration sensors 22, the control device 30, the plurality of glass vibration modules 1, and the microphone 24 are provided in the vehicle 10. The information acquisition device group 20, the plurality of vibration sensors 22, the sound output units 3 of the plurality of glass vibration modules 1, and the microphone 24 are connected by wire or wirelessly to the control device 30 so as to be able to communicate with each other. For connection with the control device 30, a communication standard such as CAN (Controller Area Network) is used, for example.

[0025] The recording device 26 is, for example, an external server having a hard disk or the like. The recording device 26 is communicably connected to the control device 30 via a network 28. Examples of the network 28 include a local area network (LAN), a wide area network (WAN), and the Internet. The recording device 26 may be configured by a storage 38 (see FIG. 11 ) described below or a hard disk or the like provided in the navigation device.

[0026] The information acquisition device group 20 includes a plurality of devices for acquiring information related to inflow noise, which is noise that flows into the interior space (hereinafter referred to as "noise-related information"). The noise-related information refers to information related to factors that affect the magnitude of the inflow noise. As an example, the information acquisition device group 20 includes a speed sensor, a navigation device, a camera, an interior sensor, a receiving unit, an occupant sensor, a glass sensor, and a storage device.

[0027] The speed sensor is a device for acquiring speed information relating to the speed of the vehicle 10. The speed information may be the speed of the vehicle 10 or the number of rotations of the wheels. The speed information may be detected by a sensor or may be acquired by a navigation device based on position information.

[0028] The navigation device is a device for acquiring roadway information regarding the roadway on which the vehicle 10 is traveling. The roadway information may include at least one of the gradient, width, shape, and type of the roadway on which the vehicle 10 is traveling. The roadway shape refers to the shape of the roadway when viewed from above. Examples of roadway shapes include straight roads, curves, corners, T-junctions, and crossroads. Examples of roadway types include paved roads, unpaved roads, general roads, and expressways. Note that instead of a navigation device, an audio device may be used that is communicably connected to a mobile terminal such as a smartphone that runs a navigation application.

[0029] The camera is a device for acquiring image information related to an image obtained by capturing an image of the road on which the vehicle 10 is traveling. The camera may be installed at any position on the vehicle 10 as long as it can capture an image of the road. The image information may include image data showing the image, or may include image processing information obtained by applying image processing to the image. The image processing information may include situation information showing the condition of the road. The situation information may include, for example, information showing the degree of dryness or wetness of the road, or information showing the degree of roughness of the road. The degree of roughness of the road may be a degree showing the number, size, or elevation difference of the road's unevenness.

[0030] An indoor sensor is a device for acquiring indoor space information regarding the state of an indoor space. The indoor sensor may be a camera or an object sensor. The camera as an indoor sensor may be installed at any position in the indoor space as long as it can capture an image of the indoor space. The image information obtained by the camera as an indoor sensor may include image data representing the image, or may include image processing information obtained by applying image processing to the image.

[0031] The indoor space information may include status information indicating the status of the indoor space. The status information may include, for example, information indicating the size, type, or position of an object placed in the indoor space. The indoor sensor may be a sensor that detects the position of a movable member (not shown) provided in the indoor space. The movable member may be a sun visor or a sunshade. The movable member may be a member that has sound-absorbing, sound-blocking, or sound-reflecting properties. The indoor space information may include position information regarding the position of the movable member. The indoor space information may also include information on at least one of the humidity and temperature of the indoor space. The indoor space information may also include information such as the fan rotation speed when the air conditioner is operating.

[0032] The receiving unit is a device for acquiring weather information related to the weather in the area in which the vehicle 10 is traveling. The receiving unit may be an audio device that receives weather information transmitted from an information providing device. The information providing device may be a mobile terminal such as a smartphone that runs a weather forecast application, or a server that distributes weather information. The weather information may include at least one of weather information indicating the type of weather, temperature information indicating the temperature, wind speed information indicating the wind speed, and wind direction information indicating the wind direction. Note that weather information may be acquired by a navigation device instead of the receiving unit.

[0033] The occupant sensor is a device for acquiring occupant information related to the occupant P. The occupant information may include information indicating the position of the occupant P, or may include information indicating the number of occupants P. The occupant sensor may be a pressure sensor or a load sensor provided in the seat. Furthermore, instead of the occupant sensor, the occupant information may be acquired by a camera provided in the interior space. Furthermore, the occupant information may include information regarding at least one of the posture and state of the occupant P. The posture of the occupant P may be determined based on the tilt angle of the seat back. The state of the occupant P may be whether or not the occupant P is driving, or whether or not the occupant P is sleeping.

[0034] The glass sensor is a device for acquiring glass state information regarding the state of the glass 14. The glass state information may include information regarding the state of the glass vibration module 1, or may include information regarding the state of the glass 14 other than the glass vibration module 1. For example, if the glass vibration module 1 is a retractable glass, the glass state information may include information indicating the opening degree of the glass vibration module 1. Furthermore, if the vehicle 10 has a retractable glass other than the glass vibration module 1, the glass state information may include information indicating the opening degree of the retractable glass. Furthermore, if the vehicle 10 has multiple retractable glass windows, the glass state information may include information indicating the position and opening degree of each retractable glass window. Furthermore, the glass state information may include at least one of the temperature of the glass 14, the pressure acting on the glass 14 due to wind while driving, the speed of wind flowing along the glass 14, and the amount of wind flowing along the glass 14.

[0035] The storage device is a device for storing various information related to the inflow noise. The storage device is configured with a hard disk or the like. The storage device may be configured with a storage 38 (see FIG. 11 ) described later. The various information related to the inflow noise may include glass characteristic information related to the characteristics of the glass 14. The glass characteristic information may include information related to at least any of the material, strength, rigidity, dimensions, and shape of the glass vibration module 1 (more specifically, the glass plate 2 shown in FIG. 2 ). Furthermore, the various information related to the inflow noise may include interior material characteristic information related to the characteristics of interior materials that absorb the inflow noise.

[0036] The noise-related information acquired by the information acquisition device group 20 does not have to include any of the above-mentioned pieces of information, and may include information related to incoming noise in addition to the above-mentioned pieces of information.

[0037] The microphone 24 is provided in the interior space. For example, the microphone 24 may be provided in the headrest of the seat where the occupant P sits. The seat where the occupant P sits may be the seat closest to the glass vibration module 1 among multiple seats provided in the vehicle 10. The microphone 24 may be provided at any position in the interior space, or may be provided for each seat, each door, or each glass 14. Furthermore, if the vehicle 10 is equipped with multiple glass vibration modules 1, the microphone 24 may be provided for each glass vibration module 1. The microphone 24 detects the sound output from the glass vibration module 1 and inflow noise, which is noise that flows into the interior space, and outputs an error signal according to the detection result to the control device 30.

[0038] The multiple vibration sensors 22 may be provided in either the interior space or the exterior space. Each vibration sensor 22 is, for example, an acceleration sensor. The acceleration sensor may be any type of acceleration sensor, such as a piezoelectric acceleration sensor, a servo acceleration sensor, or a semiconductor acceleration sensor. The multiple vibration sensors 22 may have the same configuration or different configurations. The multiple vibration sensors 22 are installed on the body of the vehicle 10. The multiple vibration sensors 22 are installed, for example, in different locations on the body. Each vibration sensor 22 outputs a reference signal to the control device 30 according to the detection result of the detected vibration.

[0039] Each vibration sensor 22 corresponds to a corresponding acoustic output unit 3. Hereinafter, when it is necessary to distinguish between two vibration sensors 22 corresponding to two acoustic output units 3 provided in one glass vibration module 1, the vibration sensor 22 corresponding to the first acoustic output unit 3A of one glass vibration module 1 will be referred to as the "first vibration sensor 22A," and the vibration sensor 22 corresponding to the second acoustic output unit 3B of one glass vibration module 1 will be referred to as the "second vibration sensor 22A." Furthermore, when it is necessary to distinguish between the reference signals output from the first vibration sensor 22A and the second vibration sensor 22B, the reference signal output from the first vibration sensor 22A will be referred to as the "first reference signal," and the reference signal output from the second vibration sensor 22B will be referred to as the "second reference signal." The first reference signal is an example of a "first signal" in the present disclosure, and the second reference signal is an example of a "second signal" in the present disclosure.

[0040] The recording device 26 is a device for recording record information. For example, the record information is information that associates the error signal with a condition under which the error signal is obtained. The condition under which the error signal is obtained includes, for example, noise-related information acquired by the information acquisition device group 20.

[0041] The control device 30 uses noise-related information input from the information acquisition device group 20, the error signal input from the microphone 24, and the recorded information recorded in the recording device 26, and generates an anti-noise signal for outputting anti-noise from the glass vibration module 1 based on the first reference signal input from the first vibration sensor 22A and the second reference signal input from the second vibration sensor 22B, and performs feedforward processing to output the anti-noise signal to the first acoustic output unit 3A and the second acoustic output unit 3B.

[0042] Hereinafter, when it is necessary to distinguish between the anti-noise signals output to the first acoustic output unit 3A and the second acoustic output unit 3B, the anti-noise signal output to the first acoustic output unit 3A will be referred to as the "first anti-noise signal," and the anti-noise signal output to the second acoustic output unit 3B will be referred to as the "second anti-noise signal." Furthermore, when it is necessary to distinguish between the anti-noise signals output by the first acoustic output unit 3A and the second acoustic output unit 3B, the anti-noise signal output by the first acoustic output unit 3A will be referred to as the "first anti-noise," and the anti-noise signal output by the second acoustic output unit 3B will be referred to as the "second anti-noise."

[0043] A first anti-noise signal is generated based on the first reference signal output from the first vibration sensor 22A. When the first anti-noise signal is input to the first acoustic output unit 3A, the vibrator 4 of the first acoustic output unit 3A vibrates, causing the glass plate 2 to vibrate, thereby outputting the first anti-noise signal from the glass vibration module 1. Furthermore, a second anti-noise signal is generated based on the second reference signal output from the second vibration sensor 22B. When the second anti-noise signal is input to the second acoustic output unit 3B, the vibrator 4 of the second acoustic output unit 3B vibrates, causing the glass plate 2 to vibrate, thereby outputting the second anti-noise signal from the glass vibration module 1. In other words, when the first anti-noise and the second anti-noise are output simultaneously from the glass vibration module 1, the first anti-noise and the second anti-noise are added together on the vibration surface of the glass plate 2, causing the anti-noise signal to be output from the glass vibration module 1. By outputting the anti-noise from the glass vibration module 1 in this manner, it is possible to cancel out the inflow noise that has entered the indoor space, thereby improving the comfort of the indoor space. The glass vibration module 1 may selectively output the first anti-noise and the second anti-noise.

[0044] Generally, when an anti-noise signal for outputting anti-noise is generated based on a reference signal output from a vibration sensor 22 for an acoustic output unit 3 installed at a certain position, if the anti-noise signal is generated based on a reference signal that is not highly related to the anti-noise, the noise cancellation effect of the anti-noise output by the acoustic output unit 3 will be reduced. Furthermore, the frequency band in which the correlation between the anti-noise and the reference signal is high varies depending on the installation position of the vibration sensor 22. Therefore, it is desirable that the acoustic output unit 3 for outputting anti-noise be assigned a vibration sensor 22 installed at a position where the correlation between the vibration detected by the vibration sensor 22 and the anti-noise detected by the microphone 24 is high in a desired frequency band.

[0045] Here, a coherence factor is an example of an index for evaluating the degree of correlation between the vibration detected by the vibration sensor 22 and the anti-noise detected by the microphone 24. Fig. 5 shows an example of the relationship between the coherence factor and frequency for the first vibration sensor 22A and the second vibration sensor 22B. Graph line A1 shows the relationship for the first vibration sensor 22A, and graph line A2 shows the relationship for the second vibration sensor 22B. As shown in Fig. 5, the frequency bands in which the coherence factor is high differ depending on the positions of the first vibration sensor 22A and the second vibration sensor 22B. Specifically, the coherence factor of the first vibration sensor 22A is high in a first frequency band, and the coherence factor of the second vibration sensor 22B is high in a second frequency band different from the first frequency band.

[0046] Based on the coherence factor shown in FIG. 5 , the first acoustic output unit 3A is assigned a first vibration sensor 22A located at a position where the coherence factor in the first frequency band is equal to or greater than a predetermined first specified value. The second acoustic output unit 3B is assigned a second vibration sensor 22B located at a position where the coherence factor in the second frequency band is equal to or greater than a predetermined second specified value. A coherence factor of less than 0.6 reduces the correlation between the anti-noise and the reference signal. Therefore, the first specified value is set to, for example, 0.6 or greater, preferably 0.7 or greater, and more preferably 0.8 or greater. Similarly, the second specified value is set to, for example, 0.6 or greater, preferably 0.7 or greater, and more preferably 0.8 or greater. The first specified value and the second specified value may be set to the same value or different values.

[0047] 6 shows a first example of noise in an indoor space detected by the microphone 24. Graph line B1 shows noise in an indoor space detected by the microphone 24 without anti-noise output. Graph line B2 shows noise in an indoor space detected by the microphone 24 when an anti-noise signal is generated based on the first reference signal output from the first vibration sensor 22A and anti-noise is output by the first acoustic output unit 3A and the second acoustic output unit 3B based on the anti-noise signal. Graph line B3 shows noise in an indoor space detected by the microphone 24 when an anti-noise signal is generated based on the second reference signal output from the second vibration sensor 22A and anti-noise is output by the first acoustic output unit 3A and the second acoustic output unit 3B based on the anti-noise signal.

[0048] As shown by graph line B2, when an anti-noise signal is generated based on the first reference signal output from the first vibration sensor 22A and the first sound output unit 3A and the second sound output unit 3B are caused to output anti-noise signals based on the anti-noise signal, the volume decreases in the first frequency band corresponding to the first vibration sensor 22A but the volume decreases less in the second frequency band corresponding to the second vibration sensor 22A. In other words, the noise cancellation effect is high in the first frequency band but low in the second frequency band.

[0049] On the other hand, as shown by graph line B3, when an anti-noise signal is generated based on the second reference signal output from the second vibration sensor 22A and the first sound output unit 3A and the second sound output unit 3B are caused to output anti-noise signals based on the anti-noise signal, the volume decreases in the second frequency band corresponding to the second vibration sensor 22A but the volume decrease is small in the first frequency band corresponding to the first vibration sensor 22A. In other words, the noise cancellation effect is high in the second frequency band but low in the first frequency band.

[0050] Therefore, it is desirable for the sound output device 50 to have both the frequency characteristics shown by graph line B2 and the frequency characteristics shown by graph line B3. In this regard, the sound output device 50 includes a first vibration sensor 22A corresponding to the first sound output unit 3A and a second vibration sensor 22B corresponding to the second sound output unit 3B. The control device 30 generates a first anti-noise signal for causing the first sound output unit 3A to output a first anti-noise signal based on the first reference signal, and outputs the first anti-noise signal to the first sound output unit 3A. The control device 30 also generates a second anti-noise signal for causing the second sound output unit 3B to output a second anti-noise signal based on a second reference signal having frequency characteristics different from those of the first reference signal, and outputs the second anti-noise signal to the second sound output unit 3B.

[0051] Here, the coherence factor indicating the degree of correlation between the first vibration detected by the first vibration sensor 22A and the first anti-noise detected by the microphone 24 is equal to or greater than a predetermined first specified value in the first frequency band. Therefore, the first anti-noise signal is generated based on the first reference signal that is highly correlated with the first anti-noise, and therefore, a high noise cancellation effect can be obtained in the first frequency band by the first anti-noise output by the first acoustic output unit 3A.

[0052] Furthermore, the coherence factor indicating the degree of correlation between the second vibration detected by the second vibration sensor 22B and the second anti-noise detected by the microphone 24 is equal to or greater than a predetermined second specified value in the second frequency band. Therefore, the second anti-noise signal is generated based on the second reference signal that is highly correlated with the second anti-noise, and therefore, a high noise cancellation effect can be obtained in the second frequency band by the second anti-noise output by the second acoustic output unit 3B.

[0053] As described above, according to the sound output device 50 of the first embodiment, the first anti-noise signal and the second anti-noise signal are generated separately based on the first reference signal and the second reference signal, and therefore a high noise cancellation effect can be obtained in both the first frequency band and the second frequency band, compared to when the first anti-noise signal and the second anti-noise signal are generated based on a common reference signal.

[0054] 7 shows a second example of noise in an indoor space detected by the microphone 24. Graph line C1 shows noise in an indoor space detected by the microphone 24 without outputting an anti-noise signal. Graph line C2 shows noise in an indoor space detected by the microphone 24 when a first anti-noise signal is generated based on a first reference signal output from the first vibration sensor 22A, the first anti-noise signal is output by the first acoustic output unit 3A based on the first anti-noise signal, a second anti-noise signal is generated based on a second reference signal output from the second vibration sensor 22B, and the second anti-noise signal is output by the second acoustic output unit 3B based on the second anti-noise signal.

[0055] As can be seen by comparing graph line C1 and graph line C2, in the first frequency band, outputting the first anti-noise reduces the volume compared to when the anti-noise is not output. Also, in the second frequency band, outputting the second anti-noise reduces the volume compared to when the anti-noise is not output. In this way, a high noise cancellation effect can be obtained in both the first frequency band and the second frequency band.

[0056] FIG. 8 shows an example of the relationship between the coherence factor and frequency. Graph line A1 shows the relationship for the first vibration sensor 22A, and graph line A2 shows the relationship for the second vibration sensor 22B. Graph line D shows the coherence factor when a reference signal is generated by summing the first and second reference signals based on the coherence factors of the first and second vibration sensors 22A and 22B. When a reference signal is generated by summing the first and second reference signals based on the coherence factors of the first and second vibration sensors 22A and 22B, the coherence factor decreases overall. Therefore, the anti-noise signal is generated based on a reference signal that is less relevant to the anti-noise signal, reducing the noise cancellation effect of the anti-noise signal. Furthermore, using modeling or a frequency-weighting algorithm to correct the overall decrease in the coherence factor increases the amount of calculation and the load on the control device 30. Furthermore, the increased amount of calculation and the increased load on the control device 30 reduce the accuracy of the anti-noise signal.

[0057] In this regard, the control device 30 generates the first anti-noise signal based on the first reference signal and the second anti-noise signal based on the second reference signal. Therefore, it is not necessary to generate a reference signal by adding the first and second reference signals, and therefore it is possible to avoid an overall decrease in the coherence factor. Furthermore, it is not necessary to use modeling or a frequency weighting algorithm to correct the overall decrease in the coherence factor. This avoids an increase in the amount of calculations, and thus an increase in the load on the control device 30, and also suppresses a decrease in the accuracy of the anti-noise signal.

[0058] Furthermore, since the sound output device 50 according to the first embodiment is provided with multiple sound output units 3 in the glass vibration module 1, anti-noise in various frequency bands can be expressed by adjusting the number of multiple sound output units 3.

[0059] In addition, since there is no need to increase the number of conventional speakers equipped with cone paper, etc., in order to express anti-noise in various frequency bands, increases in installation costs, weight, installation space, etc. in the vehicle can be suppressed.

[0060] The sound output device 50 according to the first embodiment may include a normal speaker equipped with a paper cone or the like in addition to the sound output unit 3 mounted on the glass vibration module 1, and may output anti-noise from the normal speaker in addition to the glass vibration module 1. In this case, the normal speaker may be installed anywhere in the indoor space.

[0061] Furthermore, at least one of the multiple acoustic output units 3 mounted on the glass vibration module 1 may be configured as a normal speaker equipped with a cone paper or the like, rather than being configured to output anti-noise by vibrating the glass plate 2.

[0062] Furthermore, the sound output unit 3 mounted on the glass vibration module 1 may be provided integrally with a normal speaker equipped with a paper cone or the like.

[0063] (Configuration of sound output device 50 according to second embodiment) Next, a configuration of the sound output device 50 according to the second embodiment will be described. As shown in Fig. 9 , the sound output device 50 according to the second embodiment differs from the sound output device 50 according to the first embodiment in that the control device 30 executes feedforward processing and feedback processing.

[0064] The first acoustic output unit 3A is assigned one vibration sensor 22 (the same vibration sensor 22 as the first vibration sensor 22A) among the plurality of vibration sensors 22. On the other hand, the second acoustic output unit 3B is assigned a microphone 24 that outputs an error signal as a sensor that generates a reference signal.

[0065] In the feedforward processing, a first anti-noise signal for outputting a first anti-noise from the glass vibration module 1 is generated based on a reference signal input from the vibration sensor 22 using noise-related information input from the information acquisition device group 20, an error signal input from the microphone 24, and recorded information recorded in the recording device 26, and the first anti-noise signal is output to the first acoustic output unit 3A.

[0066] On the other hand, in the feedback process, using the noise-related information input from the information acquisition device group 20, the error signal input from the microphone 24, and the recorded information recorded in the recording device 26, a second anti-noise signal for outputting a second anti-noise from the glass vibration module 1 is generated based on the error signal input from the microphone 24, and the second anti-noise signal is output to the second acoustic output unit 3B. The reference signal is an example of a "first signal" in the present disclosure, and the error signal is an example of a "second signal" in the present disclosure.

[0067] When the first anti-noise signal is input to the first acoustic output unit 3A, the vibrator 4 of the first acoustic output unit 3A vibrates, causing the glass plate 2 to vibrate, and thereby a first anti-noise is output from the glass vibration module 1. When the second anti-noise signal is input to the second acoustic output unit 3B, the vibrator 4 of the second acoustic output unit 3B vibrates, causing the glass plate 2 to vibrate, and thereby a second anti-noise is output from the glass vibration module 1. In other words, the first anti-noise and the second anti-noise are added together on the vibration surface of the glass plate 2, and thereby an anti-noise is output from the glass vibration module 1. By outputting the anti-noise from the glass vibration module 1 in this manner, not only sudden sounds and random sounds, which are inflow noises that have flowed into the indoor space, but also steady sound components that have accumulated in the indoor space can be simultaneously canceled out, thereby improving the comfort of the indoor space.

[0068] The first anti-noise signal is generated using a feedforward process, and therefore has a frequency characteristic corresponding to road noise, sudden noise caused by passing vehicles, etc. On the other hand, the second anti-noise signal is generated using a feedback process, and therefore has a frequency characteristic corresponding to glass noise, which is steady noise such as reverberation or muffled noise.

[0069] As described above, according to the sound output device 50 of the second embodiment, the first anti-noise signal and the second anti-noise signal are generated separately based on the reference signal and the error signal. Therefore, compared to the case where the first anti-noise signal and the second anti-noise signal are generated based on a common reference signal, a high noise cancellation effect can be obtained in both frequency bands, for example, the frequency band corresponding to intrusion noise, which is a random or sudden sound such as road noise or a sound caused by passing vehicles, and the frequency band corresponding to glass intrusion noise, which is a steady sound such as a reverberation or a muffled sound.

[0070] The feedforward process and the feedback process may be performed simultaneously or separately in time. That is, the first anti-noise signal and the second anti-noise signal may be output simultaneously from the glass vibration module 1, or the first anti-noise signal and the second anti-noise signal may be output selectively.

[0071] (Configuration of sound output device 50 according to third embodiment) Next, a configuration of the sound output device 50 according to the third embodiment will be described. As shown in Fig. 10 , the sound output device 50 according to the third embodiment differs from the sound output device 50 according to the second embodiment in that the control device 30 executes audio output processing in addition to feedforward processing and feedback processing.

[0072] The sound output device 50 includes an audio operation device 42. The audio operation device 42 has a touch panel display, an operation switch, or the like. The glass vibration module 1 includes a third sound output unit 3C in addition to a first sound output unit 3A and a second sound output unit 3B. The third sound output unit 3C has the same configuration as the first sound output unit 3A and the second sound output unit 3B.

[0073] In the audio output process, an audio signal is generated based on an audio operation signal input from the audio operation device 42 to the control device 30, and the audio signal is output to the third sound output unit 3C. When the audio signal is input to the third sound output unit 3C, the vibrator 4 of the third sound output unit 3C vibrates, causing the glass plate 2 to vibrate, and thereby audio sound is output from the glass vibration module 1.

[0074] The audio sound is a sound having frequency characteristics different from those of the first anti-noise and the second anti-noise, and may be, for example, music, environmental sound, or simulated noise. The music may be music from a radio broadcast, music from a television broadcast, music played over the Internet, or music played by reading data recorded on various media. The music may also be music selected by the occupant P. The environmental sound may be the sound of rain, the sound of a forest, the sound of a babbling brook, the sound of the sea, the sound of a riverbank, the chirping of birds, or the hustle and bustle of a city. The simulated noise may be an electronic sound, an engine sound, or a driving sound. If the vehicle 10 is a hybrid vehicle or an electric vehicle, the engine sound may be the engine sound of a sports car, a supercar, or various racing vehicles.

[0075] As described above, according to the sound output device 50 of the third embodiment, audio sound is output from the glass vibration module 1, thereby improving the comfort of the indoor space.

[0076] The audio signal may be added to at least one of the first anti-noise signal and the second anti-noise signal, and audio sound may be output in addition to the anti-noise signal by at least one of the first sound output unit 3A and the second sound output unit 3B. In this case, the third sound output unit 3C may be omitted.

[0077] Furthermore, the control device 30 may perform audio output processing in addition to the feedforward processing in the sound output device 50 according to the first embodiment described above.

[0078] (Configuration of the control device 30 according to the fourth embodiment) Next, the configuration of the control device 30 according to the fourth embodiment will be described. The control device 30 according to the fourth embodiment has a configuration for performing the feedforward processing according to the first embodiment. As shown in Fig. 11 , the control device 30 has a CPU (Central Processing Unit) 32, a ROM (Read Only Memory) 34, a RAM (Random Access Memory) 36, and a storage 38.

[0079] The control device 30 may be implemented as part of an ECU (Electronic Control Unit), which is a vehicle control computer, or may be implemented as an in-vehicle computer separate from the ECU. The control device 30 is an example of a "computer."

[0080] The CPU 32, ROM 34, RAM 36, and storage 38 are connected to one another via a bus 40. The CPU 32 executes various programs. Specifically, the CPU 32 reads out a program stored in the ROM 34 or the storage 38, and executes the program using the RAM 36 as a work area. The CPU 32 then performs various arithmetic processing in accordance with the program.

[0081] The ROM 34 stores various programs and various data. The RAM 36 temporarily stores programs or data as a working area. The storage 38 is configured with a recording medium such as a hard disk drive (HDD), a solid state drive (SSD), or a flash memory. The storage 38 stores various programs including an operating system and various data for arithmetic processing.

[0082] A control program 60 is stored in the storage 38. The control program is an example of a "program" in the present disclosure. The control program 60 may be stored in the ROM 34. The CPU 32 reads out the control program 60 and executes it using the RAM 36 as a work area. The CPU 32 then executes feedforward processing in accordance with the control program 60. The feedforward processing is executed by the CPU 32 operating as a filter unit 62, a cancellation unit 64, a cancellation coefficient update unit 66, a recording control unit 68, an estimation unit 70, and a filter coefficient update unit 72 in accordance with the control program 60.

[0083] As shown in FIG. 12 , the filter unit 62 includes a first filter unit 62A and a second filter unit 62B. A first reference signal and a second reference signal are selectively input to the first filter unit 62A. The first filter unit 62A performs a first filtering process on the input reference signal of the first reference signal and the second reference signal. The first filtering process includes a low-pass filter (LPF) process and a high-pass filter (HPF) process. By performing the first filtering process on the input reference signal of the first reference signal and the second reference signal, the first filter unit 62A passes only signal components corresponding to glass-induced noise and intrusion noise among the inflow noise flowing into the interior space from the glass plate 2. The cutoff frequency of the LPF process is set to, for example, 500 [Hz], and the cutoff frequency of the HPF process is set to, for example, 2000 [Hz].

[0084] Glass-induced noise is noise caused by the glass plate 2. Intrusion noise is noise that invades the indoor space from the outdoor space through the glass plate 2. Examples of glass-induced noise include resonance noise of the glass plate 2, noise caused by vibration modes when the glass plate 2 is vibrated, wind noise caused by the glass plate 2, reverberation noise caused by engine noise reverberating off the glass plate 2, and muffled noise caused in the indoor space by the glass plate 2. Reverberation noise and muffled noise are steady sounds that occur steadily. On the other hand, intrusion noise includes, for example, road noise. Road noise is a sudden sound that occurs unexpectedly.

[0085] The second filter unit 62B performs a second filtering process on the reference signal that has been subjected to the first filtering process. The second filtering process is a filtering process that cuts out signal components in the frequency band of glass-induced noise from the reference signal that has been subjected to the first filtering process. The second filtering process extracts signal components of intrusive noise from the reference signal. The cutoff frequency of the second filtering process is set to, for example, 40 Hz. The second filter unit 62B performs the second filtering process based on a filter coefficient.

[0086] The cancellation unit 64 generates an anti-noise signal that corresponds to the opposite phase of the signal component of the intruding noise extracted by the second filter unit 62B. In this case, the anti-noise signal generated for the first acoustic output unit 3A based on the first reference signal is the first anti-noise signal, and the anti-noise signal generated for the second acoustic output unit 3B based on the second reference signal is the second anti-noise signal. When the cancellation unit 64 generates the first anti-noise signal, it controls the output of the first anti-noise signal to the first acoustic output unit 3A, and when the cancellation unit 64 generates the second anti-noise signal, it controls the output of the second anti-noise signal to the second acoustic output unit 3B.

[0087] When the first anti-noise signal is input to the first sound output unit 3A, the vibrator 4 of the first sound output unit 3A vibrates, causing the glass plate 2 to vibrate, and the first anti-noise signal is output from the glass vibration module 1. As a result, the intrusion noise is attenuated by the first anti-noise signal against the intrusion noise. Similarly, when the second anti-noise signal is input to the second sound output unit 3B, the vibrator 4 of the second sound output unit 3B vibrates, causing the glass plate 2 to vibrate, and the second anti-noise signal is output from the glass vibration module 1. As a result, the intrusion noise is attenuated by the second anti-noise signal against the intrusion noise. The cancellation unit 64 selectively generates the first anti-noise signal and the second anti-noise signal based on the cancellation coefficient. The process of selectively generating the first anti-noise signal and the second anti-noise signal is, for example, a filter process on the signal component of the intrusion noise, and the cancellation coefficient is a filter coefficient used in the filter process.

[0088] The sound detected by the microphone 24 includes inflow noise flowing into the indoor space from the glass plate 2 and anti-noise generated from the glass plate 2. When the glass plate 2 generates anti-noise based on the anti-noise signal and the intrusion noise is attenuated by the anti-noise, the microphone 24 outputs, as an error signal, a signal component of the glass-induced noise obtained by subtracting the intrusion noise from the inflow noise.

[0089] The cancellation coefficient update unit 66 updates the cancellation coefficient based on the error signal. For example, the cancellation coefficient update unit 66 derives a cancellation coefficient for update using a method such as the steepest descent method or the least squares method so as to minimize the error signal, and updates the cancellation coefficient of the cancellation unit 64 using the cancellation coefficient for update.

[0090] The recording control unit 68 generates record information that associates the error signal with noise-related information that indicates the conditions when the error signal is obtained, and records the generated record information in the recording device 26. The record information may include information on all of the items included in the noise-related information, or may include information on only some of the items.

[0091] The estimation unit 70 generates estimated information based on the recorded information recorded in the recording device 26 and outputs the generated estimated information. The estimated information may be information representing an error signal when new noise-related information is obtained, or information representing a filter coefficient when new noise-related information is obtained. The estimation unit 70 may generate the estimated information using a learning model 80 stored in the storage 38. The learning model 80 may be a deep learning model. The deep learning model may be a neural network model. The learning model 80 is a trained model trained using a plurality of training data in which the noise-related information recorded in the recording device 26 is used as input data and the estimated information is used as output data.

[0092] Note that various types of learning models, such as a linear regression model, a logistic regression model, a random forest model, a boosting model, a support vector machine model, or an autoregressive model, may be used as the learning model 80. Furthermore, a calculation formula for deriving estimated information based on noise-related information may be used instead of the learning model 80. The input information used in the estimation process for generating estimated information may be information on all items included in the noise-related information, or may be information on only some of the items.

[0093] The filter coefficient update unit 72 updates the filter coefficients based on the error signal included in the record information recorded in the recording device 26. For example, when new noise-related information is obtained, the filter coefficient update unit 72 may predict the error signal by deriving an error signal that matches the conditions of the new noise-related information from the record information recorded in the recording device 26, and update the filter coefficients based on the predicted error signal. In this case, the filter coefficient update unit 72 may derive update filter coefficients using a method such as the steepest descent method or the least squares method so as to minimize the error signal, and update the filter coefficients of the second filter unit 62B using the update filter coefficients. The filter coefficient update unit 72 may also update the filter coefficients based on the estimation information estimated by the estimating unit 70.

[0094] Next, as an operation of the control device 30 according to the fourth embodiment, the flow of the feedforward processing according to the fourth embodiment will be described. The feedforward processing according to the fourth embodiment includes an anti-noise signal output process that selectively outputs a first anti-noise signal and a second anti-noise signal, a cancellation coefficient update process that updates the cancellation coefficient, a recording process that records record information, an estimation process that generates estimation information, and a filter coefficient update process that updates the filter coefficient. The cancellation coefficient update process, the recording process, the estimation process, and the filter coefficient update process are executed by interrupt processing of the anti-noise signal output process when, for example, predetermined execution conditions are met. Note that the control device 30 executes the feedforward processing, thereby executing the sound output method.

[0095] First, the flow of the anti-noise signal output process will be described with reference to FIG.

[0096] In step ST10, the CPU 32 performs a first filter process including an LPF process and an HPF process on the input reference signal of the first reference signal and the second reference signal, thereby passing only the signal components corresponding to the glass-induced noise and the intrusion noise among the inflow noise flowing into the indoor space from the glass plate 2.

[0097] In step ST12, the CPU 32 extracts the signal components of the intruding noise from the reference signal by performing a second filtering process on the reference signal that has been subjected to the first filtering process in step ST10, which cuts out the signal components in the frequency band of the glass-induced noise.

[0098] In step ST14, the CPU 32 generates an anti-noise signal corresponding to the opposite phase of the signal component of the intruding noise generated in step ST12, based on the cancellation coefficient. If the CPU 32 generates a first anti-noise signal as the anti-noise signal, it controls the first anti-noise signal to be output to the first acoustic output unit 3A. If the CPU 32 generates a second anti-noise signal as the anti-noise signal, it controls the second anti-noise signal to be output to the second acoustic output unit 3B. As a result, an anti-noise signal against the intruding noise is generated from the glass plate 2, and the intruding noise is attenuated by the anti-noise. Furthermore, as the intruding noise is attenuated by the anti-noise, the microphone 24 outputs, as an error signal, a signal component of the glass-induced noise, obtained by subtracting the intruding noise from the intruding noise.

[0099] In step ST16, the CPU 32 determines whether or not a termination condition for terminating the anti-noise signal output process is met. An example of the termination condition is that information indicating that the anti-noise signal output process is to be terminated is input to the control device 30. If the termination condition is not met, the anti-noise signal output process returns to step ST10. If the termination condition is met, the anti-noise signal output process ends.

[0100] Next, the flow of the cancellation coefficient update process will be described with reference to FIG.

[0101] In step ST20, the CPU 32 derives a cancellation coefficient for updating based on the error signal, using a method such as the steepest descent method or the least squares method, so as to minimize the error signal.

[0102] In step ST22, the CPU 32 updates the cancellation coefficient of the cancellation unit 64 using the cancellation coefficient for update derived in step ST20.

[0103] Next, the flow of the recording process will be described with reference to FIG.

[0104] In step ST30, the CPU 32 generates record information that associates noise-related information indicating the conditions under which the error signal is obtained with the error signal.

[0105] In step ST32, the CPU 32 causes the recording device 26 to record the record information generated in step ST30.

[0106] Next, the flow of the estimation process will be described with reference to FIG.

[0107] In step ST40, the CPU 32 generates estimated information based on the recorded information recorded in the recording device 26.

[0108] In step ST42, the CPU 32 outputs the estimated information generated in step ST40.

[0109] Next, the flow of the filter coefficient update process will be described with reference to FIG.

[0110] In step ST50, the CPU 32 derives filter coefficients for updating based on the error signal included in the record information recorded in the recorder 26.

[0111] In step ST52, the CPU 32 updates the filter coefficients of the second filter unit 62B using the filter coefficients for update derived in step ST50.

[0112] As described above in detail, in the control device 30 according to the fourth embodiment, the CPU 32 extracts the signal component of the intrusive noise from the reference signal by executing, based on the filter coefficient, a second filter process for cutting out the signal component in the frequency band of the glass-induced noise on the reference signal output from the vibration sensor 22. The CPU 32 then generates an anti-noise signal that corresponds to the opposite phase of the signal component of the intrusive noise, and performs control to output the generated anti-noise signal to the acoustic output unit 3. As a result, an anti-noise against the intrusive noise is generated from the glass plate 2, and the intrusive noise can be attenuated by the anti-noise.

[0113] Furthermore, the CPU 32 performs a feedforward process to generate an anti-noise signal based on a reference signal as the anti-noise signal output process. This allows for faster processing speed compared to, for example, a feedback process that generates an anti-noise signal based on an error signal. This effectively attenuates road noise and intrusive noises such as sudden noises caused by passing vehicles.

[0114] When the intruding noise is attenuated by the anti-noise in this manner, the microphone 24 outputs, as an error signal, a signal component of the glass-induced noise, which is the intruding noise minus the glass-induced noise. The CPU 32 executes a filter coefficient update process to update the filter coefficients of the second filter unit 62B based on the error signal. Here, since it is known that the error signal output from the microphone 24 is a signal component of the glass-induced noise as described above, the CPU 32 can identify the error signal as a signal component of the glass-induced noise in the filter coefficient update process. This allows for a reduction in error in the updated filter coefficient compared to, for example, a case in which the error signal is mistakenly recognized as a signal component of the anti-noise, even though it is actually a signal component of the glass-induced noise.

[0115] Similarly, the CPU 32 executes a cancellation coefficient update process that updates the cancellation coefficients based on the error signal. Here, since it is known that the error signal output from the microphone 24 is a signal component of glass-induced noise as described above, the CPU 32 can identify the error signal as a signal component of glass-induced noise in the cancellation coefficient update process. This makes it possible to reduce errors in the cancellation coefficients to be updated, compared to, for example, a case in which the error signal is mistakenly recognized as an anti-noise signal component even though it is actually a signal component of glass-induced noise.

[0116] Furthermore, the CPU 32 causes the recording device 26 to record record information associating the error signal with the conditions under which the error signal is obtained. The CPU 32 then updates the filter coefficients based on the record information recorded in the recording device 26. Therefore, when new noise-related information is obtained, the error signal can be predicted by deriving an error signal that matches the conditions of the new noise-related information from the record information recorded in the recording device 26. This makes it possible to update the filter coefficients based on the predicted error signal.

[0117] Furthermore, the CPU 32 generates estimation information based on recorded information that associates the error signal with the condition when the error signal is obtained, and updates the filter coefficients based on the generated estimation information. This allows the filter coefficients to be updated based on the estimation information when new noise-related information is obtained.

[0118] Furthermore, the CPU 32 generates the first anti-noise signal and the second anti-noise signal as anti-noise signals using common applications including the filter unit 62, the cancellation unit 64, the cancellation coefficient update unit 66, the recording control unit 68, the estimation unit 70, and the filter coefficient update unit 72. This reduces the load on the CPU 32 compared to when different applications are used to generate the first anti-noise signal and the second anti-noise signal.

[0119] The feedforward process according to the fourth embodiment includes a recording process for recording record information and an estimation process for generating estimated information, but at least one of the recording process and the estimation process may be omitted.

[0120] Furthermore, in the case where feedforward processing is executed for the first acoustic output unit 3A and feedback processing is executed for the second acoustic output unit 3B (see FIGS. 9 and 10 ) as in the control device 30 according to the second or third embodiment described above, the feedforward processing according to the fourth embodiment may be applied to the feedforward processing executed for the first acoustic output unit 3A. That is, as shown in FIG. 18 , in the feedforward processing executed for the first acoustic output unit 3A, a first anti-noise signal may be generated based on a reference signal input from the vibration sensor 22 corresponding to the first acoustic output unit 3A, using noise-related information input from the information acquisition device group 20, an error signal input from the microphone 24, and recorded information recorded in the recording device 26, and the first anti-noise signal may be output to the first acoustic output unit 3A.

[0121] (Configuration of the control device 30 according to the fifth embodiment) Next, the configuration of the control device 30 according to the fifth embodiment will be described. The control device 30 according to the fifth embodiment has a configuration for performing feedback processing in addition to the configuration for performing feedforward processing according to the second or third embodiment. The configuration for performing feedforward processing according to the second or third embodiment is as described using FIG. 18 . Below, the configuration for performing feedback processing of the control device 30 according to the fifth embodiment will be described. Note that the hardware configuration of the control device 30 in the fifth embodiment is the same as that in the fourth embodiment.

[0122] As shown in FIG. 19 , a control program 90 is stored in the storage 38. The control program is an example of a "program" in the present disclosure. The control program 90 may be stored in the ROM 34. The CPU 32 reads out the control program 90 and executes the control program 90 using the RAM 36 as a work area. The CPU 32 then executes feedback processing in accordance with the control program 90. The feedback processing according to the fifth embodiment is executed by the CPU 32 operating as a difference processing unit 92, a cancellation unit 94, a cancellation coefficient update unit 96, a recording control unit 98, and an estimation unit 100 in accordance with the control program 90.

[0123] 20 , the differential processing unit 92 generates a differential signal by differentially processing the anti-noise signal component estimated by the estimation unit 100 (described later) from the error signal output from the microphone 24. Note that in the fifth embodiment, intrusion noise, which is a sudden sound such as road noise, is ignored, and the error signal includes a signal component of windshield-induced noise and a signal component of anti-noise. Therefore, in the fifth embodiment, the differential signal generated by differentially processing the anti-noise signal component from the error signal can be considered to be the signal component of windshield-induced noise.

[0124] The cancellation unit 94 generates an anti-noise signal corresponding to the opposite phase of the signal component of the glass-induced noise generated by the differential processing unit 92, and controls output of the generated second anti-noise signal to the second acoustic output unit 3B. As a result, anti-noise against the glass-induced noise is generated from the glass plate 2, and the glass-induced noise is attenuated by the anti-noise. The cancellation unit 94 generates the anti-noise signal based on a cancellation coefficient. The process of generating the anti-noise signal is, for example, a filter process on the signal component of the glass-induced noise, and the cancellation coefficient is a filter coefficient used in the filter process.

[0125] The cancellation coefficient update unit 96 updates the cancellation coefficients based on the signal components of the glass-induced noise generated by the differential processing unit 92. For example, the cancellation coefficient update unit 96 derives cancellation coefficients for update using a method such as the steepest descent method or the least squares method so as to minimize the signal components of the glass-induced noise, and updates the cancellation coefficients of the cancellation unit 94 using the cancellation coefficients for update.

[0126] The recording control unit 98 generates recording information that associates the error signal with the conditions under which the error signal is obtained, and causes the recording device 26 to record the generated recording information. The conditions under which the error signal is obtained include noise-related information and an anti-noise signal. The noise-related information included in the recording information may include information on all of the noise-related information items, or may include information on only some of the items.

[0127] The estimation unit 100 estimates the anti-noise signal component based on the record information recorded in the recording device 26. For example, the estimation unit 100 may estimate the anti-noise signal as the anti-noise signal component when new noise-related information and an error signal are obtained based on the record information. The estimation unit 100 may also estimate the anti-noise signal component using a learning model 110 stored in the storage 38. The learning model 110 may be a deep learning model. The deep learning model may be a neural network model. The learning model 110 is a trained model trained using a plurality of training data in which the noise-related information and the error signal from the record information recorded in the recording device 26 are used as input data and the anti-noise signal from the record information is used as output data.

[0128] Note that various learning models such as a linear regression model, a logistic regression model, a random forest model, a boosting model, a support vector machine model, or an autoregressive model may be used as the learning model 110. Furthermore, a calculation formula for deriving an anti-noise signal component based on noise-related information and an error signal may be used instead of the learning model 110. The noise-related information used in the estimation process for estimating the anti-noise signal component may be information on all items of the noise-related information, or may be information on only some items.

[0129] In addition, when feedforward processing is performed simultaneously in addition to feedback processing, the estimation unit 100 may estimate an anti-noise signal component including a first anti-noise output by the feedforward processing and a second anti-noise output by the feedback processing.

[0130] Next, the flow of feedback processing according to the fifth embodiment will be described as an operation of the control device 30 according to the fifth embodiment. The feedback processing according to the fifth embodiment includes an anti-noise signal output process that outputs an anti-noise signal, a cancellation coefficient update process that updates the cancellation coefficient, and a recording process that records record information. The cancellation coefficient update process and the recording process are executed by interrupt processing for the anti-noise signal output process when, for example, predetermined execution conditions are met. Note that the control device 30 executes the feedforward process and the feedback process, thereby executing the sound output method.

[0131] First, the flow of the anti-noise signal output process will be described with reference to FIG.

[0132] In step ST60, the CPU 32 estimates the anti-noise signal component based on the record information recorded in the recorder 26.

[0133] In step ST62, the CPU 32 generates a differential signal by performing differential processing on the anti-noise signal component estimated in step ST60 from the error signal output from the microphone 24. Here, since intrusion noise, which is a sudden sound such as road noise, is ignored, the signal component of windshield-induced noise is generated as a differential signal.

[0134] In step ST64, the CPU 32 generates an anti-noise signal corresponding to the opposite phase of the signal component of the glass-induced noise generated in step ST62, and performs control to output a second anti-noise signal as the generated anti-noise signal to the second acoustic output unit 3B. As a result, an anti-noise against the glass-induced noise is generated from the glass plate 2, and the glass-induced noise is attenuated by the anti-noise.

[0135] In step ST66, the CPU 32 determines whether or not a termination condition for terminating the anti-noise signal output process is met. An example of the termination condition is that information indicating that the anti-noise signal output process is to be terminated is input to the control device 30. If the termination condition is not met, the anti-noise signal output process returns to step ST60. If the termination condition is met, the anti-noise signal output process ends.

[0136] Next, the flow of the cancellation coefficient update process will be described with reference to FIG.

[0137] In step ST70, the CPU 32 derives a cancellation coefficient based on the signal component of the glass-induced noise generated in step ST62. For example, the cancellation coefficient update unit 96 derives an updated cancellation coefficient using a method such as the steepest descent method or the least squares method so as to minimize the signal component of the glass-induced noise.

[0138] In step ST72, the CPU 32 updates the cancellation coefficient of the cancellation unit 94 using the cancellation coefficient for update derived in step ST70.

[0139] Next, the flow of the recording process will be described with reference to FIG.

[0140] In step ST80, the CPU 32 generates record information that associates the error signal with the conditions under which the error signal is obtained (that is, the noise-related information and the anti-noise signal).

[0141] In step ST82, the CPU 32 causes the recording device 26 to record the record information generated in step ST80.

[0142] As described above in detail, in the control device 30 according to the fifth embodiment, the CPU 32 generates a signal component of glass-induced noise as a differential signal by performing differential processing on the anti-noise signal component estimated by the estimation process from the error signal output from the microphone 24. The CPU 32 then generates an anti-noise signal that corresponds to the opposite phase of the signal component of the glass-induced noise, and performs control to output the generated anti-noise signal to the acoustic output unit 3. As a result, anti-noise against the glass-induced noise is generated from the glass plate 2, and the glass-induced noise can be attenuated by the anti-noise.

[0143] Furthermore, the CPU 32 performs feedback processing to generate an anti-noise signal based on an error signal as the anti-noise signal output processing. Therefore, the accuracy of the anti-noise signal can be improved compared to, for example, feedforward processing that generates an anti-noise signal based on a reference signal. This can effectively attenuate glass penetration noise, which is a steady sound such as a reverberation or a muffled sound.

[0144] Furthermore, the CPU 32 executes a cancellation coefficient update process that updates the cancellation coefficients based on the signal components of the glass-induced noise. Here, since it is known that the signal components used for updating the cancellation coefficients are signal components of the glass-induced noise as described above, the CPU 32 can identify that the signal components used for updating are signal components of the glass-induced noise in the cancellation coefficient update process. This makes it possible to reduce errors in the cancellation coefficients to be updated compared to, for example, a case where the signal components used for updating are mistakenly recognized as signal components of the anti-noise noise when they are in fact signal components of the glass-induced noise.

[0145] Furthermore, the CPU 32 causes the recording device 26 to record record information associating the error signal with the condition when the error signal is obtained. The CPU 32 then estimates the anti-noise signal component based on the record information recorded in the recording device 26. Therefore, by performing differential processing on the anti-noise signal component estimated by the estimation process from the error signal output from the microphone 24, it is possible to generate the glass-induced noise signal component as a differential signal. This makes it possible to generate an anti-noise signal and update the cancellation coefficient based on the glass-induced noise signal component.

[0146] (Configuration of the control device 30 according to the sixth embodiment) Next, the configuration of the control device 30 according to the sixth embodiment will be described. In the sixth embodiment, the functions of the differential processing unit 92, the cancellation unit 94, the cancellation coefficient update unit 96, and the estimation unit 100 are different from those of the fifth embodiment. The differences will be described below.

[0147] 24 , the differential processing unit 92 generates a differential signal by differentially processing the signal component of the glass-induced noise estimated by the estimation unit 100 (described later) from the error signal output from the microphone 24. Note that in the sixth embodiment, road noise and intrusion noise, which are sudden sounds caused by passing vehicles, are also ignored, and the error signal includes a signal component of the glass-induced noise and a signal component of anti-noise. Therefore, in the sixth embodiment, the differential signal generated by differentially processing the signal component of the glass-induced noise from the error signal can be considered to be the signal component of the anti-noise.

[0148] The cancellation unit 94 generates an anti-noise signal corresponding to the opposite phase of the signal component of the glass-induced noise estimated by the estimation unit 100 (described later), and controls the output of the generated second anti-noise signal to the second acoustic output unit 3B. As a result, anti-noise against the glass-induced noise is generated from the glass plate 2, and the glass-induced noise is attenuated by the anti-noise. The cancellation unit 94 generates the anti-noise signal based on a cancellation coefficient. The process of generating the anti-noise signal is, for example, a filter process on the signal component of the glass-induced noise, and the cancellation coefficient is a filter coefficient used in the filter process.

[0149] The cancellation coefficient update unit 96 updates the cancellation coefficients based on the anti-noise signal components generated by the differential processing unit 92. For example, the cancellation coefficient update unit 96 derives cancellation coefficients for update using a method such as the steepest descent method or the least squares method so as to minimize the anti-noise signal components, and updates the cancellation coefficients of the cancellation unit 94 using the cancellation coefficients for update.

[0150] The recording control unit 98 generates recording information that associates the error signal with the conditions under which the error signal is obtained, and causes the recording device 26 to record the generated recording information. The conditions under which the error signal is obtained include noise-related information and an anti-noise signal. The noise-related information included in the recording information may include information on all of the noise-related information items, or may include information on only some of the items.

[0151] The estimation unit 100 estimates the signal component of the glass-induced noise based on the record information recorded in the recording device 26. For example, the recording device 26 may store record information that associates the error signal with noise-related information and anti-noise signals, which are conditions when an error signal is obtained, and the estimation unit 100 may estimate, based on the record information, the anti-noise signal when new noise-related information and an error signal are obtained as the anti-noise signal component, and estimate the signal component of the glass-induced noise by performing differential processing on the anti-noise signal component from the error signal.

[0152] The estimation unit 100 may also estimate the signal component of glass-induced noise using a learning model 110 stored in the storage 38. The learning model 110 is a trained model trained using a plurality of training data sets in which noise-related information and an error signal from the record information recorded in the recording device 26 are used as input data and an anti-noise signal from the record information is used as output data. The estimation unit 100 may then estimate the signal component of glass-induced noise by differentially processing the anti-noise signal component derived by the learning model 110 from the error signal. The learning model 110 may also be a trained model trained using a plurality of training data in which noise-related information and an error signal from the record information recorded in the recording device 26 are used as input data and the signal component of glass-induced noise obtained by differentially processing the anti-noise signal from the error signal is used as output data.

[0153] Next, the flow of feedback processing according to the sixth embodiment will be described as an operation of the control device 30 according to the sixth embodiment. The feedback processing according to the sixth embodiment includes an anti-noise signal output process that outputs an anti-noise signal, a cancellation coefficient update process that updates the cancellation coefficient, and a recording process that records record information. The cancellation coefficient update process and the recording process are executed by interrupt processing of the anti-noise signal output process when predetermined execution conditions are met, for example. Note that the recording process is similar to the recording process according to the fifth embodiment (see FIG. 23 ), and therefore a description thereof will be omitted.

[0154] First, the flow of the anti-noise signal output process will be described with reference to FIG.

[0155] In step ST90, the CPU 32 estimates the signal component of the glass-induced noise based on the recorded information recorded in the recording device 26.

[0156] In step ST92, the CPU 32 generates an anti-noise signal corresponding to the opposite phase of the signal component of the glass-induced noise estimated in step ST90, and performs control to output the generated second anti-noise signal as the anti-noise signal to the second acoustic output unit 3B. As a result, an anti-noise against the glass-induced noise is generated from the glass plate 2, and the glass-induced noise is attenuated by the anti-noise.

[0157] In step ST94, the CPU 32 determines whether or not a termination condition for terminating the anti-noise signal output process is met. An example of the termination condition is that information indicating that the anti-noise signal output process is to be terminated is input to the control device 30. If the termination condition is not met, the anti-noise signal output process returns to step ST90. If the termination condition is met, the anti-noise signal output process ends.

[0158] Next, the flow of the cancellation coefficient update process will be described with reference to FIG.

[0159] In step ST100, the CPU 32 generates a differential signal by performing differential processing on the signal component of the windshield-induced noise estimated in step ST90 from the error signal output from the microphone 24. Here, since intrusion noise, which is a sudden sound such as road noise, is ignored, an anti-noise signal component is generated as the differential signal.

[0160] In step ST102, the CPU 32 derives a cancellation coefficient based on the anti-noise signal component as the differential signal generated in step ST100. For example, the cancellation coefficient update unit 96 derives the cancellation coefficient for update using a method such as the steepest descent method or the least squares method so as to minimize the anti-noise signal component.

[0161] In step ST104, the CPU 32 updates the cancellation coefficient of the cancellation unit 94 using the cancellation coefficient for update derived in step ST102.

[0162] As described above in detail, in the control device 30 according to the sixth embodiment, the CPU 32 generates an anti-noise signal component as a differential signal by performing differential processing on the signal component of the glass-induced noise estimated by the estimation process from the error signal output from the microphone 24. The CPU 32 then generates an anti-noise signal that corresponds to the opposite phase of the signal component of the glass-induced noise estimated by the estimation process, and performs control to output the generated anti-noise signal to the acoustic output unit 3. As a result, an anti-noise against the glass-induced noise is generated from the glass plate 2, and the glass-induced noise can be attenuated by the anti-noise.

[0163] Furthermore, the CPU 32 performs feedback processing to generate an anti-noise signal based on an error signal as the anti-noise signal output processing. Therefore, the accuracy of the anti-noise signal can be improved compared to, for example, feedforward processing that generates an anti-noise signal based on a reference signal. This can effectively attenuate glass penetration noise, which is a steady sound such as a reverberation or a muffled sound.

[0164] Furthermore, the CPU 32 executes a cancellation coefficient update process that updates the cancellation coefficients based on the anti-noise signal component. Here, since it is known that the update signal component for updating the cancellation coefficient is an anti-noise signal component as described above, in the cancellation coefficient update process, the CPU 32 can identify that the update signal component is an anti-noise signal component. This makes it possible to reduce errors in the cancellation coefficients to be updated, compared to, for example, a case in which the update signal component is an anti-noise signal component but is mistakenly recognized as a signal component of glass-induced noise.

[0165] The CPU 32 also records, in the recording device 26, record information associating the error signal with the condition when the error signal is obtained. The CPU 32 then estimates the signal component of the glass-induced noise based on the record information recorded in the recording device 26. Therefore, by performing differential processing on the signal component of the glass-induced noise estimated by the estimation process from the error signal output from the microphone 24, it is possible to generate an anti-noise signal component as a differential signal. This makes it possible to update the cancellation coefficient based on the anti-noise signal component. Furthermore, it is possible to generate an anti-noise signal based on the signal component of the glass-induced noise estimated by the estimation process.

[0166] (Configuration of the control device 30 according to the seventh embodiment) Next, the control device 30 according to the seventh embodiment will be described. In the seventh embodiment, the CPU 32 functions only as a difference processing unit 92, a cancellation unit 94, and a cancellation coefficient update unit 96, and the function of the difference processing unit 92 differs from that of the fifth embodiment. The differences will be described below.

[0167] 27 , the differential processing unit 92 generates a differential signal by differentially processing the anti-noise signal component serving as an anti-noise signal output by a cancellation unit 94 (described later) from the error signal output from the microphone 24. Note that in the seventh embodiment, sudden intrusion noise such as road noise is also ignored, and the error signal includes a signal component of windshield-induced noise and an anti-noise signal component. Therefore, in the seventh embodiment, the differential signal generated by differentially processing the anti-noise signal component from the error signal can be considered to be the signal component of windshield-induced noise.

[0168] Next, as an operation of the control device 30 according to the seventh embodiment, the flow of feedback processing according to the seventh embodiment will be described. The feedback processing according to the seventh embodiment includes an anti-noise signal output process that outputs an anti-noise signal, and a cancellation coefficient update process that updates the cancellation coefficient. Note that the cancellation coefficient update process is similar to the cancellation coefficient update process according to the fifth embodiment described above (see FIG. 22 ), and therefore a description thereof will be omitted.

[0169] The flow of the anti-noise signal output process will be described below with reference to FIG.

[0170] In step ST110, the CPU 32 generates a differential signal by differentially processing the anti-noise signal component as an anti-noise signal from the error signal output from the microphone 24. Note that in the first step ST110, the CPU 32 uses a predetermined anti-noise signal component as the anti-noise signal. In this way, the signal component of the glass-induced noise is generated as a differential signal.

[0171] In step ST112, the CPU 32 generates an anti-noise signal corresponding to the opposite phase of the signal component of the glass-induced noise generated in step ST110, and performs control to output a second anti-noise signal as the generated anti-noise signal to the second acoustic output unit 3B. As a result, an anti-noise against the glass-induced noise is generated from the glass plate 2, and the glass-induced noise is attenuated by the anti-noise. The anti-noise signal generated in step ST112 is used as the anti-noise signal component in step ST110 of the next routine.

[0172] In step ST114, the CPU 32 determines whether or not a termination condition for terminating the anti-noise signal output process is met. An example of the termination condition is that information indicating that the anti-noise signal output process is to be terminated is input to the control device 30. If the termination condition is not met, the anti-noise signal output process returns to step ST110. If the termination condition is met, the anti-noise signal output process ends.

[0173] As described above in detail, in the control device 30 according to the sixth embodiment, the CPU 32 performs differential processing on the anti-noise signal component serving as the anti-noise signal generated in the anti-noise signal output processing from the error signal, thereby generating the signal component of the glass-induced noise as a differential signal. Therefore, compared to the case where the anti-noise signal component is generated by estimation processing as in the fifth embodiment, the processing load of the CPU 32 can be reduced by the amount corresponding to the elimination of the estimation processing.

[0174] (Configuration of the control device 30 according to the eighth embodiment) Next, the control device 30 according to the eighth embodiment will be described. In the eighth embodiment, the CPU 32 functions only as a difference processing unit 92, a cancellation unit 94, and a cancellation coefficient update unit 96, and the function of the difference processing unit 92 differs from that of the sixth embodiment. The differences will be described below.

[0175] 29 , a vibration detection device 120 is connected to the control device 30. The vibration detection device 120 is provided on the glass plate 2, detects vibrations occurring in the glass plate 2, and outputs a vibration detection signal corresponding to the detection result to the control device 30. The vibration detection device 120 has a sensor such as a piezoelectric element, a voice coil motor, an acceleration sensor, a MEMS (Micro Electro Mechanical Systems) sensor, or a pickup microphone as a sensor for detecting vibrations occurring in the glass plate 2. The vibration detection signal can be considered to be a signal component of glass-induced noise.

[0176] The differential processing unit 92 generates a differential signal by differentially processing the vibration detection signal as a signal component of glass-induced noise from the error signal output from the microphone 24. Note that in the eighth embodiment, sudden intrusion noise such as road noise is also ignored, and the error signal includes a signal component of glass-induced noise and a signal component of anti-noise. Therefore, in the eighth embodiment, the differential signal generated by differentially processing the vibration detection signal as a signal component of glass-induced noise from the error signal can be considered to be the signal component of anti-noise.

[0177] The cancellation unit 94 generates an anti-noise signal corresponding to the opposite phase of the vibration detection signal as a signal component of the glass-induced noise output from the vibration detection device 120, and controls the output of the generated second anti-noise signal as a second anti-noise signal to the second acoustic output unit 3B.

[0178] Next, as an operation of the control device 30 according to the eighth embodiment, the flow of feedback processing according to the eighth embodiment will be described. The feedback processing according to the eighth embodiment includes an anti-noise signal output process that outputs an anti-noise signal, and a cancellation coefficient update process that updates the cancellation coefficient. Note that the cancellation coefficient update process is similar to the cancellation coefficient update process according to the sixth embodiment described above (see FIG. 26 ), and therefore a description thereof will be omitted.

[0179] The flow of the anti-noise signal output process will be described below with reference to FIG.

[0180] In step ST120, the CPU 32 generates a differential signal by differentially processing the vibration detection signal as the signal component of the glass-induced noise from the error signal output from the microphone 24. As a result, an anti-noise signal component is generated as the differential signal.

[0181] In step ST122, the CPU 32 generates an anti-noise signal corresponding to the opposite phase of the vibration detection signal as a signal component of the glass-induced noise output from the vibration detection device 120, and performs control to output a second anti-noise signal as the generated anti-noise signal to the second acoustic output unit 3B. As a result, an anti-noise against the glass-induced noise is generated from the glass plate 2, and the glass-induced noise is attenuated by the anti-noise.

[0182] In step ST124, the CPU 32 determines whether or not a termination condition for terminating the anti-noise signal output process is met. An example of the termination condition is that information indicating that the anti-noise signal output process is to be terminated is input to the control device 30. If the termination condition is not met, the anti-noise signal output process returns to step ST110. If the termination condition is met, the anti-noise signal output process ends.

[0183] As described above in detail, in the control device 30 according to the eighth embodiment, the glass plate 2 is provided with the vibration detection device 120, and the CPU 32 generates an anti-noise signal component as a differential signal by performing differential processing on the vibration detection signal as a signal component of glass-induced noise output from the vibration detection device 120 from the error signal. Therefore, compared to the case where glass-induced noise is generated by estimation processing as in the sixth embodiment, the processing load of the CPU 32 can be reduced by the amount corresponding to the elimination of estimation processing.

[0184] (Example of Specifications of Glass Vibration Module 1) Next, an example of specifications of the glass vibration module 1 will be described. When anti-noise signals are output by acoustic output units 3 mounted at different positions on one glass plate 2 based on different anti-noise signals, if adjacent acoustic output units 3 are mounted too close together, there is a risk that the vibrations will cancel each other out within the vibration plane of the glass plate 2, distorting the anti-noise waveform. Therefore, it is preferable to mount adjacent acoustic output units 3 at positions far enough apart to prevent the vibrations from canceling out each other within the vibration plane of the glass plate 2. For example, adjacent acoustic output units 3 should be mounted at least 5 mm apart, preferably 10 mm or more, and more preferably 20 mm or more. There is no particular upper limit to the distance between adjacent acoustic output units 3.

[0185] Mounting the acoustic output units 3 at positions where the curvature of the glass plate 2 is large is more preferable, as it makes it difficult for the anti-noises output by adjacent acoustic output units 3 to be canceled out. In order to make it difficult for the anti-noises output by adjacent acoustic output units 3 to be canceled out, the arc radius r of the glass plate 2 is preferably 30,000 mm or less, more preferably 10,000 mm or less, even more preferably 5,000 mm or less, and particularly preferably 3,000 mm or less. There is no particular lower limit for the arc radius r of the glass plate 2, but for convenience of bending, it is preferably 1 mm or more.

[0186] In the case of a glass plate 2 having an intermediate layer, the attenuation coefficient of the glass plate 2 is high, the anti-noise is attenuated within the vibration plane of the glass plate 2, and the anti-noise is less likely to be canceled out between adjacent sound output units 3. Specifically, the attenuation coefficient is preferably 0.001 or more, more preferably 0.005 or more, and even more preferably 0.01 or more.

[0187] When the acoustic output unit 3 is a voice coil type actuator, the resonance frequency is preferably between 20 and 2000 Hz. When multiple voice coil type actuators are used, the resonance frequencies of the actuators may be the same or different.

[0188] (Modifications common to the above-described embodiments) Next, modifications common to the above-described embodiments will be described.

[0189] In each of the above embodiments, the sound output device 50 is applied to a vehicle 10. However, as described above, the sound output device 50 may be applied to various types of moving objects, or to buildings such as homes or office buildings. In buildings such as homes or office buildings, for example, glass-induced noise includes wind noise, and intrusion noise includes the operating noise of outdoor fans or motors, as well as various outdoor noises. Therefore, by applying the sound output device 50 to buildings such as homes or office buildings, the glass-induced noise and intrusion noise may be attenuated. Furthermore, the sound output device 50 may be applied to a glass-enclosed space within a building such as a home or office building to attenuate noise such as conversation sounds that intrude into the space from another space. Furthermore, the sound output device 50 may be applied to a glass sound barrier (soundproof wall) installed on the side of a road to attenuate noise that intrudes from the space outside the sound barrier to the space inside. Furthermore, the sound output device 50 may be applied to a factory to attenuate noise leaking from the space inside the factory to the space outside.

[0190] Furthermore, in each of the above embodiments, a CPU 32 is exemplified for the control device 30, but instead of or together with the CPU 32, at least one other CPU, at least one GPU (Graphics Processing Unit), and / or at least one TPU (Tensor processing unit) may be used.

[0191] Although the above embodiments have exemplified an example in which the control program 60 or the control program 90 is pre-stored in the storage 38, the control program 60 or the control program 90 may be stored in a portable, non-transitory, computer-readable storage medium (hereinafter simply referred to as a "non-transitory storage medium") such as an SSD (Solid State Drive) or a USB (Universal Serial Bus) memory. The control program 60 or the control program 90 stored in the non-transitory storage medium may then be installed in the control device 30.

[0192] In addition, the control program 60 or the control program 90 may be stored in a storage device such as another computer or server device connected to the control device 30 via the network 28, and the control program 60 or the control program 90 may be downloaded and installed in the control device 30 in response to a request from the control device 30.

[0193] Furthermore, it is not necessary to store all of the control program 60 or the control program 90 in the storage device of another computer, server device, etc. connected to the control device 30, or in the storage 38; only a portion of the control program 60 or the control program 90 may be stored.

[0194] In addition, in each of the above embodiments, the control device 30 is exemplified as a computer including a CPU 32, a ROM 34, a RAM 36, and a storage 38. However, instead of a computer, a device including an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), and / or a PLD (Programmable Logic Device) may be applied. Furthermore, instead of a computer, a combination of a hardware configuration and a software configuration may be used.

[0195] Furthermore, the hardware resources that execute the various processes described in the above embodiments can be various processors, as listed below. Examples of processors include a CPU, which is a general-purpose processor that functions as a hardware resource that executes various processes by executing software, i.e., a program. Examples of processors include dedicated electronic circuits, such as FPGAs, PLDs, and ASICs, which are processors with a circuit configuration specifically designed to execute specific processes. Each processor has built-in or connected memory, and each processor executes various processes by using the memory.

[0196] The hardware resources that execute various processes may be configured with one of these various processors, or may be configured with a combination of two or more processors of the same or different types (for example, a combination of multiple FPGAs, or a combination of a CPU and an FPGA). Also, the hardware resources that execute various processes may be a single processor.

[0197] As an example of a system configured with a single processor, first, one processor is configured by combining one or more CPUs and software, and this processor functions as a hardware resource that executes various processes. Second, there is a system that uses a processor that realizes the functions of the entire system, including multiple hardware resources that execute various processes, on a single IC (Integrated Circuit) chip, as typified by SoC (System-on-a-Chip). In this way, various processes are realized using one or more of the above-mentioned various processors as hardware resources.

[0198] Furthermore, the hardware structure of these various processors can be, more specifically, an electronic circuit that combines circuit elements such as semiconductor devices. The above process is merely an example. Therefore, it goes without saying that unnecessary steps may be deleted, new steps may be added, or the processing order may be rearranged, without departing from the spirit of the present invention.

[0199] The above-described description and illustrations are a detailed explanation of the parts related to the present disclosure and are merely an example of the present disclosure. For example, the above description of the configuration, functions, actions, and effects is an explanation of an example of the configuration, functions, actions, and effects of the parts related to the present disclosure. Therefore, it goes without saying that unnecessary parts may be deleted, new elements may be added, or elements may be replaced with other parts from the above-described description and illustrations, as long as they do not deviate from the gist of the present disclosure. Furthermore, in order to avoid confusion and facilitate understanding of the parts related to the present disclosure, the above-described description and illustrations omit explanations of common general technical knowledge that do not require particular explanation to enable the implementation of the present disclosure.

[0200] The disclosure of Japanese Patent Application No. 2024-003262 is incorporated herein by reference in its entirety.

[0201] Furthermore, all publications, patent applications, and technical standards mentioned in this specification are incorporated by reference herein to the same extent as if each individual publication, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

[0202] Below, supplementary notes regarding the above-described embodiments will be disclosed.

[0203] (Supplementary Note 1) An acoustic output device comprising: a glass plate; a plurality of acoustic output units provided on the glass plate; and a control device that controls the plurality of acoustic output units, wherein the control device generates a first anti-noise signal based on a first signal, for causing a first acoustic output unit of the plurality of acoustic output units to output a first anti-noise signal, and outputs the first anti-noise signal to the first acoustic output unit, and generates a second anti-noise signal based on a second signal having frequency characteristics different from the first signal, for causing a second acoustic output unit of the plurality of acoustic output units to output a second anti-noise signal, and outputs the second anti-noise signal to the second acoustic output unit. (Supplementary Note 2) The acoustic output device according to Supplementary Note 1, wherein the first signal is a first reference signal output from a first vibration sensor corresponding to the first acoustic output unit in response to a first vibration, and the second signal is a second reference signal output from a second vibration sensor corresponding to the second acoustic output unit in response to a second vibration. (Supplementary Note 3) The sound output device according to Supplementary Note 2, wherein when the first anti-noise signal is generated based on the first reference signal output from the first vibration sensor in response to the first vibration, the first sound output unit is caused to output the first anti-noise signal based on the first anti-noise signal, and the first anti-noise is detected by a microphone, a coherence factor indicating a degree of association between the first vibration detected by the first vibration sensor and the first anti-noise detected by the microphone is equal to or greater than a predetermined first specified value in a first frequency band; and when the second anti-noise signal is generated based on the second reference signal output from the second vibration sensor in response to the second vibration, the second sound output unit is caused to output the second anti-noise signal based on the second anti-noise signal, and the second anti-noise is detected by the microphone, a coherence factor indicating a degree of association between the second vibration detected by the second vibration sensor and the second anti-noise detected by the microphone is equal to or greater than a predetermined second specified value in a second frequency band.(Supplementary Note 4) The sound output device according to Supplementary Note 3, wherein the first frequency band and the second frequency band are different frequency bands. (Supplementary Note 5) The sound output device according to any one of Supplements 1 to 4, wherein the control device generates the first anti-noise signal and the second anti-noise signal using a common application. (Supplementary Note 6) The sound output device according to Supplementary Note 1, wherein the first signal is a reference signal output from a vibration sensor, and the second signal is an error signal output from an error sensor that detects the sound output from the glass plate and inflow noise. (Supplementary Note 7) The sound output device according to any one of Supplements 1 to 6, wherein the control device generates an audio signal for causing a third sound output unit of the plurality of sound output units to output an audio sound different from the first anti-noise and the second anti-noise, and outputs the audio signal to the third sound output unit. (Supplementary Note 8) An automotive glass module comprising: a glass plate; and a plurality of acoustic output units provided on the glass plate, wherein a first anti-noise signal is output by a first acoustic output unit of the plurality of acoustic output units, and a second anti-noise signal having frequency characteristics different from those of the first anti-noise signal is output by a second acoustic output unit of the plurality of acoustic output units. (Supplementary Note 9) An acoustic output method comprising: generating a first anti-noise signal, based on a first signal, for causing a first acoustic output unit of the plurality of acoustic output units to output the first anti-noise signal, and outputting the first anti-noise signal to the first acoustic output unit; generating a second anti-noise signal, based on a second signal having frequency characteristics different from those of the first signal, for causing a second acoustic output unit of the plurality of acoustic output units to output a second anti-noise signal, and outputting the second anti-noise signal to the second acoustic output unit.(Supplementary Note 10) A program for causing a computer to execute a process including: generating a first anti-noise signal based on a first signal, for causing a first acoustic output unit among a plurality of acoustic output units provided on a glass plate to output a first anti-noise signal, and outputting the first anti-noise signal to the first acoustic output unit; generating a second anti-noise signal based on a second signal having frequency characteristics different from those of the first signal, for causing a second acoustic output unit among the plurality of acoustic output units to output a second anti-noise signal, and outputting the second anti-noise signal to the second acoustic output unit.

Claims

1. An acoustic output device, comprising: a glass plate; a plurality of acoustic output units provided on the glass plate; and a control device configured to control the plurality of acoustic output units, wherein the control device generates a first anti-noise signal for outputting first anti-noise by a first acoustic output unit among the plurality of acoustic output units based on a first signal, outputs the first anti-noise signal to the first acoustic output unit, generates a second anti-noise signal for outputting second anti-noise by a second acoustic output unit among the plurality of acoustic output units based on a second signal having frequency characteristics different from those of the first signal, and outputs the second anti-noise signal to the second acoustic output unit.

2. The acoustic output device according to claim 1, wherein the first signal is a first reference signal output in response to a first vibration from a first vibration sensor corresponding to the first acoustic output unit, and the second signal is a second reference signal output in response to a second vibration from a second vibration sensor corresponding to the second acoustic output unit.

3. The first anti-noise signal is generated based on the first reference signal output in response to the first vibration from the first vibration sensor, the first anti-noise is output by the first acoustic output unit based on the first anti-noise signal, and when the first anti-noise is detected by a microphone, a coherence factor indicating the degree of correlation between the first vibration detected by the first vibration sensor and the first anti-noise detected by the microphone is equal to or greater than a predetermined first specified value in a first frequency band. The second anti-noise signal is generated based on the second reference signal output in response to the second vibration from the second vibration sensor, the second anti-noise is output by the second acoustic output unit based on the second anti-noise signal, and when the second anti-noise is detected by the microphone, a coherence factor indicating the degree of correlation between the second vibration detected by the second vibration sensor and the second anti-noise detected by the microphone is equal to or greater than a predetermined second specified value in a second frequency band. The acoustic output device according to claim 2.

4. The acoustic output device according to claim 3, wherein the first frequency band and the second frequency band are different frequency bands.

5. The control device generates the first anti-noise signal and the second anti-noise signal using a common application. The acoustic output device according to any one of claims 1 to 4.

6. The first signal is a reference signal output from a vibration sensor, and the second signal is an error signal output from an error sensor that detects sound and inflow noise output from the glass plate. The acoustic output device according to claim 1.

7. The control device generates an audio signal for causing a third acoustic output unit among the plurality of acoustic output units to output an audio sound different from the first anti-noise and the second anti-noise, and outputs the audio signal to the third acoustic output unit. The acoustic output device according to any one of claims 1 to 6.

8. A glass plate and a plurality of acoustic output units provided on the glass plate, wherein a first acoustic output unit among the plurality of acoustic output units outputs a first anti-noise, and a second acoustic output unit among the plurality of acoustic output units outputs a second anti-noise having frequency characteristics different from those of the first anti-noise. An automotive glass module.

9. A first anti-noise signal for causing a first acoustic output unit among a plurality of acoustic output units provided on a glass plate to output a first anti-noise is generated based on a first signal, and the first anti-noise signal is output to the first acoustic output unit. A second anti-noise signal for causing a second acoustic output unit among the plurality of acoustic output units to output a second anti-noise is generated based on a second signal having frequency characteristics different from those of the first signal, and the second anti-noise signal is output to the second acoustic output unit. An acoustic output method including this. A program for causing a computer to execute a process including: generating a first anti-noise signal for outputting first anti-noise by a first acoustic output unit among a plurality of acoustic output units provided on a glass plate based on a first signal, and outputting the first anti-noise signal to the first acoustic output unit; generating a second anti-noise signal for outputting second anti-noise by a second acoustic output unit among the plurality of acoustic output units based on a second signal having frequency characteristics different from those of the first signal, and outputting the second anti-noise signal to the second acoustic output unit.

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