The present disclosure relates to a vibration generating device.
Japanese Laid-Open Patent Application No. 2001-121079 (Patent Document 1) discloses a vibration source drive device that has an object to generate sound and vibration exclusively.
However, even if adopting the vibration source drive device disclosed in Patent Document 1, it is difficult to generate sound and vibration that are sufficiently separated.
According to an embodiment in the present disclosure, a vibration generating device includes a housing; a diaphragm supported by the housing, and configured to generate sound by vibrating in a first direction; and a vibration providing part attached to the housing, and configured to vibrate the housing, wherein the vibration providing part vibrates the housing in the first direction at a first frequency, and vibrates the housing in a second direction at a second frequency lower than the first frequency.
In the following, embodiments in the present disclosure will be described with reference to the accompanying drawings.
According to the present disclosure, sound and vibration that are sufficiently separated can be presented.
Note that throughout the description and the drawings, for elements having substantially the same functional configurations, duplicate descriptions may be omitted by attaching the same reference codes.
First, a first embodiment will be described.
As illustrated in
The diaphragm 240 is supported by the housing 260, and generates sound by vibrating in a first direction (the Z1-Z2 direction). The vibration providing part 220 is attached to the housing 260, to vibrate the housing 260. The vibration providing part 220 vibrates the housing 260 in the first direction at the first frequency f1, and vibrates the housing 260 in a second direction at a second frequency f2 that is lower than the first frequency f1. For example, the second direction is a direction different from the first direction, and favorably is a direction (the X1-X2 direction or the Y1-Y2 direction) orthogonal to the first direction (the Z1-Z2 direction).
For example, the diaphragm 240 can be integrally formed with the housing 260. For example, the diaphragm 240 can be integrally formed with the upper case 230. Also, for example, the housing 260 and the diaphragm 240 are made of synthetic resin or made of metal.
In the vibration generating device 200, the housing 260 vibrating in the first direction causes the diaphragm 240 to vibrate in the first direction, and the diaphragm 240 vibrating the surrounding air generates sound. The first frequency f1 is not limited in particular, and may be set to be, for example, greater than or equal to 200 Hz and less than or equal to 6 kHz; in particular, it is favorable that the range is set to be, for example, greater than or equal to 1 kHz and less than or equal to 4 kHz that can be easily detected by the auditory perception of a person. Even if the housing 260 vibrates at a frequency in a range that can be easily detected by the auditory perception of a person, the vibration is hardly detected by the person through the tactile perception. Therefore, vibration at the first frequency f1 in the first direction can present sound to a person without causing the person to feel the vibration substantially.
Also, the second frequency f2 is not limited in particular, and may be set to be, for example, less than or equal to 600 Hz; in particular, it is favorable that the range is set to be, for example, greater than or equal to 100 Hz and less than or equal to 500 Hz that can be easily detected by the tactile perception of a person. Even in the case where the first frequency f1 is greater than or equal to 200 Hz and less than or equal to 600 Hz, the second frequency f2 simply needs to be lower than the first frequency f1. In some cases, the auditory perception of a person can detect frequencies of sound that are easily detected by the tactile perception; however, when vibrating in the second direction, the diaphragm 240 hardly vibrates in the first direction, and thereby, the diaphragm 240 does not generate sound. Therefore, vibration at the second frequency f2 in the second direction can present vibration to a person without causing the person to feel sound substantially.
Here, the vibration providing part 1 according to the first example of the vibration providing part 220 will be described.
In the vibration providing part 1 according to the first example, the Z1-Z2 direction is an example of a first direction; the X1-X2 direction is an example of a second direction; and the Y1-Y2 direction is an example of a third direction.
First, a configuration of the vibration providing part 1 will be described by using
As illustrated in
As illustrated in
The holder 30 and the elastic supporter 40 are integrally formed by processing a metal plate having a spring property, to have a predetermined shape. As illustrated in
As illustrated in
Also, as illustrated in
Note that a plate spring having such a folded structure as in the elastic supporter 40, has a feature in that elastic deformation occurs more easily in directions orthogonal to the folds (the left-right direction and the up-down direction). In other words, such a plate spring can be elastically deformed along the left-right direction due to expansion and contraction, and elastically deformed along the up-down direction by deflection. On the other hand, such a plate spring also has a feature in that deformation hardly occurs in the direction along the folds (in the front-back direction), and hence, is suitable as a member for suppressing movement along the front-back direction.
Also, in a plate spring having such a folded structure, elastic deformation along the left-right direction due to expansion and contraction is normally more likely to occur, compared to elastic deformation along the up-down direction due to deflection. Therefore, defining the modulus of elasticity of the elastic supporter 40 in the left-right direction as the first modulus of elasticity, and defining the modulus of elasticity of the elastic supporter 40 in the up-down direction as the second modulus of elasticity, then, the first modulus of elasticity and the second modulus of elasticity take values different from each other.
The attachment 43 is formed at the tip of the elastic supporter 40. An engaging claw part 43a is formed at a predetermined position of the attachment 43. Further, by having of the engaging claw part 43a engaged with the main body 11 of the housing 10, the elastic supporter 40 is attached to the housing 10. Further, by elastic deformation along the left-right direction and along the up-down direction, the elastic supporter 40 supports the vibrator 20 to be capable of vibrating along the left-right direction and along the up-down direction.
Note that being supported by the elastic supporter 40, the vibrator 20 vibrates along the left-right direction at the first natural frequency that is determined according to the first modulus of elasticity and the mass of the vibrator 20, and vibrates along the up-down direction at the second natural frequency that is determined according to the second modulus of elasticity and the mass of the vibrator 20. Further, as the first modulus of elasticity and the second modulus of elasticity take different values from each other, the first natural frequency and the second natural frequency take different values from each other.
As illustrated in
The electromagnet 60 generates a magnetic field along the front-back direction by causing an alternating current to flow through the coil 63, to magnetize the front edge 61F and the rear edge 61R of the core 61 to have different poles. Further, by adopting an alternating current as the current flowing through the coil 63, the magnetic field generated by the electromagnet 60 is an alternating magnetic field in which the direction of the magnetic field changes in response to change in the direction of the current. Further, when the front edge 61F of the core 61 is serving as an S pole, the rear edge 61R is serving as an N pole, and when the front edge 61F of the core 61 is serving as an N pole, the rear edge 61R is serving as an S pole. The timing and the frequency of the alternating magnetic field generated by the electromagnet 60 are controlled by the external circuit described above.
As illustrated in
Also, the permanent magnet 70 has a slit 72 that is formed to extend diagonally from the upper left to the lower right of the magnetized face 71. Further, the magnetized face 71 is partitioned into two magnetized regions 73 by the slit 72, and the two magnetized regions 73 are magnetized to be magnetic poles different from each other. In this way, the permanent magnet 70 is magnetized to have different magnetic poles aligned along the left-right direction and along the up-down direction, respectively.
In the following, the permanent magnet 70 arranged on the front edge side of the housing 10 will be referred to as the permanent magnet 70 on the front side; and the permanent magnet 70 arranged on the rear edge side of the housing 10 will be referred to as the permanent magnet 70 on the rear side. Also, among the two magnetized regions 73, a region on the lower left side will be referred to as the first magnetized region 73a; and a region on the upper right side will be referred to as the second magnetized region 73b. Further, it is assumed in the following description that in the permanent magnet 70 on the front side, the first magnetized region 73a becomes an S pole and the second magnetized region 73b becomes an N pole; and in the permanent magnet 70 on the rear side, the first magnetized region 73a becomes an N pole and the second magnetized region 73b becomes an S pole.
Also, a yoke 74 as a member made of a ferromagnetic material is attached to the permanent magnet 70, for directing the magnetic field generated by the permanent magnet 70 toward the electromagnet 60. The vibration providing part 1 has a configuration like this.
Next, operations of the vibration providing part 1 will be described by using
Further, as illustrated in
Also, as illustrated in
In this way, in the magnetic drive part 50, every time the direction of the magnetic field generated by the electromagnet 60 is inverted, the front edge 61F and the rear edge 61R of the magnetic core 61 of the electromagnet 60 attract or repel the first magnetized region 73a of the permanent magnet 70 to or from each other, and repel or attract the second magnetized region 73b from or to each other. Further, the magnetic drive part 50 uses the magnetic forces between the electromagnet 60 and the permanent magnet 70, to drive the vibrator 20 in the left-right direction and in the up-down direction.
On the other hand, as described earlier, the vibrator 20 is supported by the elastic supporter 40, to be capable of vibrating along the left-right direction and along the up-down direction. Further, the vibrator 20 vibrates along the left-right direction at the first natural frequency that is determined according to the first modulus of elasticity and the mass of the vibrator 20, and vibrates along the up-down direction at the second natural frequency that is determined according to the second modulus of elasticity and the mass of the vibrator 20.
Therefore, as illustrated in
By using such a relationship between the frequency of the alternating magnetic field and the easiness of vibration of the vibrator 20, the magnetic drive part 50 vibrates the vibrator 20 along the left-right direction by the alternating magnetic field at the same frequency as the first natural frequency, and vibrates the vibrator 20 along the up-down direction by the alternating magnetic field at the same frequency as the second natural frequency. In the following, vibrating the vibrator 20 along the left-right direction by the alternating magnetic field at the same frequency as the first natural frequency, will be referred as to driving the vibrator 20 in the left-right direction at the first natural frequency; and vibrating the vibrator 20 along the up-down direction by the alternating magnetic field at the same frequency as the second natural frequency, will be referred as to driving the vibrator 20 in the up-down direction at the second natural frequency.
Next, a method of stabilizing vibrating operations of the vibrator 20 will be described. As described earlier, a plate spring having such a folded structure like the elastic supporter 40, has a feature in that elastic deformation occurs easier in a direction orthogonal to the folds, whereas deformation hardly occurs in the direction along the folds. Therefore, in the vibration providing part 1, by using the feature of the plate spring, deformation of the elastic supporter 40 along the front-back direction is suppressed; and thereby, movement of the vibrator 20 along the front-back direction is suppressed, and vibrating operations of the vibrator 20 along the left-right direction and along the up-down direction are stabilized.
Moreover, in the plate spring having such a folded structure, a width dimension of the flat part 42 greater than the length dimension of the flat part 42 makes deformation along the folds more difficult. In the vibration providing part 1, by using the feature of the plate spring having such a folded structure, the elastic supporter 40 is formed so as to have the width dimension of the flat part 42 greater than the length dimension of the flat part 42, and thereby, deformation of the elastic supporter 40 along the front-back direction can be suppressed more easily.
Also, in the plate spring having such a folded structure, although the outer periphery of the flat part 42 greatly influences the difficulty of deformation of the elastic supporter 40 along the folds, the influence of part of the flat part 42 away from the outer periphery (part closer to the center) is smaller than the influence of the outer periphery of the flat part 42. On the other hand, by foaming the opening 42a at a part away from the outer periphery of the flat part 42, the mechanical strength in directions orthogonal to the folds of the flat part 42 (in the left-right direction and in the up-down direction) can be reduced, and thereby, the elastic supporter 40 can be made elastically deformable more easily in the directions orthogonal to the folds.
By using the feature of the plate spring having such a folded structure, the vibration providing part 1 according to the first example is configured to have the opening 42a famed at a position away from the outer periphery of the flat part 42, so as to have elastic deformation occur easier along the left-right direction and along the up-down direction, while the deformability of the elastic supporter 40 along the front-back direction is suppressed. Further, by adjusting the dimensions of the opening 42a, the elastic deformability of the elastic supporter 40 along the left-right direction and along the up-down direction can be adjusted.
Next, effects of the vibration providing part 1 will be described. In the vibration providing part 1, the elastic supporter 40 is a plate spring formed to have the multiple folded parts 41 in which the folds are folded along the front-back direction (third direction) orthogonal to the left-right direction (first direction) and to the up-down direction (second direction), and the two flat parts 42 that have generally a rectangular shape and extend from one of the multiple folded parts 41 to another. A plate spring having such a folded structure, has a feature in that elastic deformation occurs easier in a direction orthogonal to the folds, whereas deformation hardly occurs in the direction along the folds. Therefore, elastic deformation of the elastic supporter 40 along the left-right direction and along the up-down direction can occur easily, and deformability of the elastic supporter 40 along the front-back direction can be suppressed. As a result, even when a force along the front-back direction acts on the vibrator 20 by a magnetic force between the electromagnet 60 (the first magnetic field generating part) and the permanent magnet 70 (the second magnetic field generating part), movement of the vibrator 20 along the front-back direction can be suppressed, and vibrating operations along the left-right direction and along the up-down direction of the vibrator 20 can be stabilized.
Also, in the vibration providing part 1, by foaming the opening 42a at a position away from the outer periphery of the flat part 42, while suppressing the deformability of the elastic supporter 40 along the front-back direction, elastic deformation can occur easier along the left-right direction and along the up-down direction. Further, by adjusting the dimensions of the opening 42a, the elastic deformability of the elastic supporter 40 along the left-right direction and along the up-down direction can be adjusted. As a result, while stabilizing the vibrating operations of the vibrator 20, the vibrator 20 can be easily vibrated along the left-right direction and along the up-down direction, and the easiness of vibration of the vibrator 20 can be adjusted.
Also, in the vibration providing part 1, by forming the elastic supporter 40 so as to have the width dimension of the flat part 42 (the dimension in the direction along the folds) greater than the length dimension of the flat part 42 (the dimension along the extending direction), the deformation of the elastic supporter 40 along the front-back direction can be further suppressed, and the vibrating operations of the vibrator 20 can be further stabilized.
Also, in the vibration providing part 1, the magnetic drive part 50 driving the vibrator 20 at the first natural frequency corresponding to the first modulus of elasticity and the mass of the vibrator 20, makes the vibrator 20 easily vibrated along the left-right direction, and hardly vibrated along the up-down direction. Also, the magnetic drive part 50 driving the vibrator 20 at the second natural frequency corresponding to the second modulus of elasticity and the mass of the vibrator 20, makes the vibrator 20 easily vibrated along the up-down direction, and hardly vibrated along the left-right direction. As a result, while stabilizing the vibrating operations of the vibrator 20, desired vibrating operations of the vibrator 20 along the left-right direction and along the up-down direction can be implemented.
Also, in the vibration providing part 1, by the alternating magnetic field generated by the electromagnet 60, the magnetic core 61 on the electromagnet 60 side can be attracted to or repelled from the first magnetized region 73a as one of the magnetic poles on the permanent magnet 70 side, and the core 61 can be repelled from or attracted to the second magnetized region 73b as the other pole on the permanent magnet 70 side. Further, by using the magnetic forces between the electromagnet 60 and the permanent magnets 70, the vibrator 20 can be easily vibrated along the left-right direction and along the up-down direction. Moreover, even when the magnetic forces act between the permanent magnets 70 and the electromagnet 60, deformation of the elastic supporter 40 along the front-back direction is suppressed; therefore, the vibrating operations of the vibrator 20 can be stabilized. Therefore, such a vibration providing part 1 is suitable in the case of driving the vibrator 20 by using the magnetic forces between the electromagnet 60 and the permanent magnets 70.
Such a vibration providing part 1 can be used, for example, by attaching the lower end of the main body 11 or the cover 12 to the bottom plate 211 of the housing 260.
As long as the predetermined functions can be implemented, the configuration of the vibration providing part 1 may be changed appropriately. For example, two elastic supporters 40 may be attached directly to the vibrator 20. In this case, the holder 30 becomes unnecessary. Also, the vibration providing part 1 may further include members other than those described above.
Also, as long as the predetermined functions can be implemented, the materials and/or the shapes of the housing 10, the holder 30, and the elastic supporter 40 may be changed appropriately. For example, the number of folds of the plate spring as the elastic supporter 40 may be a number other than that described above. Also, the shape of the flat part 42 and/or the shape of the opening 42a may be shapes other than those described above. Also, the elastic supporter 40 may be formed using a separate member from the holder 30, and then, combined with the holder 30.
Also, as long as the predetermined functions can be implemented, the configuration of the magnetic drive part 50 may be changed appropriately. For example, the permanent magnet 70 may be arranged on either one of the front edge side or the rear edge side of the housing 10. Also, as long as different magnetic poles are arranged along the left-right direction and along the up-down direction, respectively, the shape of the slit 72 may be other than that described above. Also, multiple permanent magnets magnetized to be different magnetic poles along the left-right direction and along the up-down direction may be arranged in the housing 10.
Also, as long as the predetermined functions can be implemented, the magnetic drive part 50 may drive the vibrator 20 at a vibration frequency other than the first natural frequency and the second natural frequency. For example, the magnetic drive part 50 not only drives the vibrator 20 along the left-right direction at the first natural frequency and drives the vibrator 20 along the up-down direction at the second natural frequency, but also may drive the vibrator 20 in an oblique direction at an intermediate vibration frequency between the first natural frequency and the second natural frequency.
Next, a vibration providing part 2 according to a second example of the vibration providing part 220 will be described.
In the vibration providing part 2 according to the second example, the Z1-Z2 direction is an example of a first direction; and the Y1-Y2 direction is an example of a second direction.
As illustrated in
The fixed yoke 110 further includes a central protruding part 112 protruding upward (on the Z1 side) from the center of the base 111; a first side protruding part 114A protruding upward from an edge (front edge) of the base 111 on the Y1 side in the longitudinal direction; and a second side protruding part 114B protruding upward from an edge (rear edge) of the base 111 on the Y2 side in the longitudinal direction. The first side protruding part 114A and the second side protruding part 114B are arranged at positions between which the central protruding parts 112 is interposed in the X1-X2 direction. The fixed yoke 110 further includes a first iron core 113A protruding upward from the base 111, between the central protruding part 112 and the first side protruding part 114A; and a second iron core 113B protruding upward from the base 111, between the central protruding part 112 and the second side protruding part 114B. The first excitation coil 130A is wound around the first iron core 113A, and the second excitation coil 130B is wound around the second iron core 113B. The first rubber 140A is arranged on the first side protruding part 114A, and the second rubber 140B is arranged on the second side protruding part 114B. The central protruding part 112 is an example of a first protruding part, and the first side protruding part 114A and the second side protruding part 114B are examples of second protruding parts.
The movable yoke 120 is plate-shaped, and has a generally rectangular planar shape. The movable yoke 120 contacts the first rubber 140A and the second rubber 140B at its edges in the longitudinal direction. The permanent magnet 160 is attached to a surface of the movable yoke 120 on the fixed yoke 110 side. The permanent magnet 160 includes a first region 161, a second region 162 positioned on the Y1 side of the first region 161, and a third region 163 positioned on the Y2 side of the first region 161. For example, the first region 161 is magnetized to be an S pole, and the second and third regions 162 and 163 are magnetized to be N poles. Furthermore, the permanent magnet 160 is attached to the movable yoke 120 at substantially the center in plan view, so that the first region 161 is opposite to the central protruding part 112; a boundary 612 between the first region 161 and the second region 162 is opposite to the first excitation coil 130A; and a boundary 613 between the first region 161 and the third region 163 is opposite to the second excitation coil 130B. Also, the boundary 612 is positioned on the Y2 side relative to the axial core of the first excitation coil 130A, and the boundary 613 is positioned on the Y1 side relative to the axial core of the second excitation coil 130B. In other words, the boundary 612 is positioned on the Y2 side relative to the center of first iron core 113A, and the boundary 613 is positioned on the Y1 side relative to the center of second iron core 113B. The permanent magnet 160 magnetizes the fixed yoke 110 and the movable yoke 120, and the magnetic attractive force biases the movable yoke 120 in the Z1-Z2 direction toward the fixed yoke 110. Also, the magnetic attractive force biases both ends of the movable yoke 120 in the Y1-Y2 direction to approach the first side protruding part 114A and the second side protruding part 114B, respectively.
When vibration is generated in the housing 260, the vibration providing part 2 is driven so that the directions of respective currents flowing in the first excitation coil 130A and the second excitation coil 130B are inverted alternately. In other words, by alternately inverting the direction of the current flowing in each of the first excitation coil 130A and the second excitation coil 130B, the pole on a surface of the first iron core 113A facing the movable yoke 120 and the pole on a surface of the second iron core 113B facing the movable yoke 120 are to alternately inverted independently from each other. As a result, according to the direction of a current flowing through the first excitation coil 130A, and the direction of a current flowing through the second excitation coil 130B, the permanent magnet 160 and the movable yoke 120 reciprocate in the Y1-Y2 direction or the Z1-Z2 direction. A relationship between directions of currents and directions of motions will be described later.
For example, the first rubber 140A and the second rubber 140B have a rectangular planar shape whose longitudinal direction corresponds to the X1-X2 direction. The first rubber 140A is interposed between the first side protruding part 114A and the movable yoke 120, and the second rubber 140B is interposed between the second side protruding part 114B and the movable yoke 120. In other words, the first rubber 140A and the second rubber 140B are interposed between the fixed yoke 110 and the movable yoke 120. Therefore, unless intentionally disassembled, the first rubber 140A and the second rubber 140B are held between the fixed yoke 110 and the movable yoke 120. Note that the first rubber 140A may be fixed to the top surface of the first side protruding part 114A, fixed to the bottom surface of the movable yoke 120, or fixed to the both; and the second rubber 140B may be fixed to the upper surface of the second side protruding part 114B, fixed to the bottom surface of the movable yoke 120, or fixed to the both.
Here, a relationship between directions of currents and directions of motions will be described. In total, there are four types of combinations in terms of the direction of a current flowing through the first excitation coil 130A, and the direction of a current flowing through the second excitation coil 130B.
In the first combination, when viewed from the Z1 side, currents flow through the first excitation coil 130A and the second excitation coil 130B counter-clockwise.
In the second combination, when viewed from the Z1 side, currents flow through the first excitation coil 130A and the second excitation coil 130B clockwise.
Therefore, by repeating the first combination and the second combination so that currents flows through the first excitation coil 130A and the second excitation coil 130B in the same direction, the movable yoke 120 reciprocates in the Z1-Z2 direction. In other words, by energizing the first excitation coil 130A and the second excitation coil 130B, the movable yoke 120 vibrates in the Z1-Z2 direction with the neutral position being the position in the initial state.
In the third combination, when viewed from the Z1 side, a current flows through the first excitation coil 130A counter-clockwise, and a current flows through the second excitation coil 130B clockwise.
In the fourth combination, when viewed from the Z1 side, a current flows through the first excitation coil 130A clockwise, and a current flows through the second excitation coil 130B counter-clockwise.
Therefore, by repeating the third combination and the fourth combination so that currents flows through the first excitation coil 130A and the second excitation coil 130B in the opposite directions, the movable yoke 120 reciprocates in the Y1-Y2 direction. In other words, by energizing the first excitation coil 130A and the second excitation coil 130B, the movable yoke 120 vibrates in the Y1-Y2 direction with the neutral position being the position in the initial state.
Such a vibration providing part 2 can be used, for example, by attaching a surface of the movable yoke 120 on the Z1 side to the bottom plate 211 of the housing 260.
Next, a second embodiment will be described. The second embodiment differs from the first embodiment in tams of the relationship between the housing and the diaphragm.
As illustrated in
In the vibration generating device 300, the housing 310 vibrating in the first direction causes the diaphragm 312 to vibrate in the first direction through the deflection of the coupling part 311, and the diaphragm 312 vibrating the surrounding air generates sound. Also, when vibrating in the second direction, the diaphragm 312 hardly vibrates in the first direction, and hence, the diaphragm 312 does not generate sound.
Therefore, as in the first embodiment, by vibration at the first frequency f1 in the first direction, sound can be presented to a person with virtually no vibration felt by the person, and by vibration at the second frequency f2 in the second direction, vibration can be presented to the person with virtually no sound felt by the person.
For example, the diaphragm 312 can be integrally famed with the coupling part 311 and the housing 310. Also, for example, the housing 310, the coupling part 311, and the diaphragm 312 are made of synthetic resin. The diaphragm 312 may be have a thickness equivalent to the thickness of the coupling part 311, or may be thinner or thicker than the coupling part 311.
The application of the vibration generating device in the present disclosure is not limited in particular, and can be used, for example, for presenting vibration and sound to persons who are riding in an automobile. For example, presentation for alerting only the driver to a low-urgency matter can be provided by vibration in the driver's seat, whereas presentation for alerting all occupants in the automobile to a high-urgency matter can be provided by sound spreading throughout the entire interior of the automobile. The location at which the vibration generating device in the present disclosure is installed is not limited in particular, and can be embedded, for example, in the bearing surface or the backrest of the driver's seat.
Also, vibration and sound may be presented from multiple vibration generating devices to a single user. For example, by using multiple vibration generating devices to present the vibration or sound in multiple directions, lively presentation can be provided.
Also, according to the first and second embodiments, although sound and vibration can be adequately separated when being presented to the user, in some applications, sound and vibration may be intentionally mixed when being presented to the user.
Also, as signals input into the vibration generating device in the present disclosure, a signal at the first frequency f1 (high-frequency signal) and a signal at the second frequency f2 (low-frequency signal) may be input separately, or a signal in which the signal at the first frequency f1 and the signal at the second frequency f2 are superimposed (superimposed signal) may be input.
As described above, the favorable embodiments and the like have been described in detail; note that the embodiments and the like can be changed and replaced in various ways without deviating from the scope described in the claims.
Number | Date | Country | Kind |
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2019-047616 | Mar 2019 | JP | national |
The present U.S. non-provisional application is a continuation application of and claims the benefit of priority under 35 U.S.C. § 365(c) from PCT International Application PCT/JP2020/007014 filed on Feb. 21, 2020, which is designated the U.S., and is based upon and claims the benefit of priority of Japanese Patent Application No. 2019-047616 filed on Mar. 14, 2019, the entire contents of which are incorporated herein by reference.
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Number | Date | Country | |
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20210387231 A1 | Dec 2021 | US |
Number | Date | Country | |
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Parent | PCT/JP2020/007014 | Feb 2020 | WO |
Child | 17446351 | US |