WO2019177150A1 - Dispositif de génération d'ondes sonores électrostatiques et haut-parleur électrostatique - Google Patents

Dispositif de génération d'ondes sonores électrostatiques et haut-parleur électrostatique Download PDF

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Publication number
WO2019177150A1
WO2019177150A1 PCT/JP2019/010845 JP2019010845W WO2019177150A1 WO 2019177150 A1 WO2019177150 A1 WO 2019177150A1 JP 2019010845 W JP2019010845 W JP 2019010845W WO 2019177150 A1 WO2019177150 A1 WO 2019177150A1
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Prior art keywords
fixed electrode
vibrating
electrode
sound wave
voltage
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PCT/JP2019/010845
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English (en)
Japanese (ja)
Inventor
朋宏 片岡
敏幸 ▲高▼橋
西尾　英俊
純夫 堀池
田中　秀治
ヨーク フロメル
大高　剛一
真徳 室山
Original Assignee
オムロン株式会社
国立大学法人東北大学
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Application filed by オムロン株式会社, 国立大学法人東北大学 filed Critical オムロン株式会社
Publication of WO2019177150A1 publication Critical patent/WO2019177150A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/02—Loudspeakers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers, loudspeakers or microphones
    • H04R3/04—Circuits for transducers, loudspeakers or microphones for correcting frequency response
    • H04R3/06—Circuits for transducers, loudspeakers or microphones for correcting frequency response of electrostatic transducers

Definitions

  • the present invention relates to a capacitive sound wave generator and a capacitive speaker.
  • those generally used as speakers that output sound waves in the audible range include dynamic speakers, balanced armature speakers, capacitive speakers, and the like.
  • the dynamic type speaker vibrates the cone by electromagnetic driving and has a characteristic that the sound range is wide.
  • the dynamic type speaker has a disadvantage of low response because the mass of the cone to be vibrated is large.
  • a small speaker such as an earphone has a problem that the responsiveness is further deteriorated because the inertial force of the diaphragm is relatively large.
  • the balanced armature type speaker vibrates an iron piece by electromagnetic driving, and is characterized in that it is easy to miniaturize and consumes less power, but has a disadvantage that the sound range is narrow.
  • an electrostatic speaker that solves such a problem is used (for example, see Patent Documents 1-5).
  • this capacitive speaker two fixed electrodes are arranged so as to sandwich the diaphragm.
  • the electrostatic attraction generated between the diaphragm and each fixed electrode is used by charging the diaphragm positively or negatively and charging each fixed electrode by sending an electric signal of the opposite polarity to the diaphragm. Then, the diaphragm is vibrated to output sound waves. Since this capacitance type speaker does not have a coil or the like attached to the diaphragm, high response can be realized. In addition, there is an advantage that the structure is simple and power consumption is low.
  • the capacitance type speaker as described above has low power consumption, but it is necessary to apply a high voltage (100 to 200 V) between the vibration electrode and the fixed electrode in order to output a sufficient sound pressure.
  • a booster circuit that boosts voltage from a low battery voltage (within several volts) is required, which may increase device cost and power consumption.
  • a method of increasing the electrode area can be considered, but in mobile devices and wearable devices where the speaker size is limited, the area of the speaker There were constraints and cost issues. For the reasons described above, it has been difficult to mount a capacitive speaker in mobile devices and wearable devices that have restrictions on both power consumption and speaker size.
  • the penetration provided through the thickness It is composed of a fixed electrode having a hole, a vibration electrode that is arranged so as to face the fixed electrode and is movable with respect to the fixed electrode, and a connecting member that connects the two vibration electrodes through the through hole.
  • Capacitance-type speakers that have been adapted are also proposed.
  • the present invention has been made in view of the prior art as described above, and an object of the present invention is to suppress the occurrence of pull-in in the capacitive sound wave generator, and thereby to improve the reliability of the capacitive sound wave generator. It is to provide technology that can improve performance.
  • the present invention has been made to solve the above-described problem, and has a plate-like shape and a fixed electrode having one or a plurality of through holes provided so as to penetrate in the thickness direction; Two sheets having a plate-like or film-like shape, arranged so as to face the fixed electrode, with the fixed electrode interposed therebetween, and at least a central portion of the fixed electrode being provided so as to be movable in the thickness direction; A vibrating electrode, A connecting member for connecting the two vibrating electrodes through the through hole; With A capacitance-type sound wave generator, wherein a dielectric layer is provided in at least a part of a region on both surfaces of the fixed electrode facing the two vibrating electrodes.
  • the two vibrating electrodes can be vibrated as a unit based on the electrostatic force between the fixed electrode not provided with the sound hole and the two vibrating electrodes disposed with the fixed electrode interposed therebetween. it can.
  • the area of the electrode for generating an electrostatic force can be increased as compared with a conventional sound wave generator in which a plurality of sound holes are provided in the fixed electrode, and the vibrating electrode is vibrated more efficiently.
  • the fixed electrode has a through-hole through which the connecting member is passed. The area of the through-hole is significantly larger than the total area of the sound holes of the fixed electrode in a normal capacitive sound wave generator. Since it can be made smaller, there is no problem.
  • a dielectric layer is provided in at least a part of the regions on both sides of the fixed electrode facing the two vibrating electrodes.
  • the thickness of the dielectric layer is t 1
  • the dielectric constant of the dielectric layer is ⁇ 1
  • the distance between the vibrating electrode and the dielectric layer is g
  • the fixed electrode and the two vibrating electrodes are each moved or deformed in the same direction by an electrostatic attractive force generated between the two vibrating electrodes and the fixed electrode.
  • An acoustic signal input means for applying a voltage between the two may be further provided.
  • At least one of the fixed electrode and the two vibrating electrodes may be fixed at the peripheral edge thereof. According to this, the positions and movements of the fixed electrode and the vibration electrode can be further stabilized, and the quality of the sound wave generated by the sound wave generator can be improved.
  • the acoustic signal input means is Applying a positive or negative bias voltage to the fixed electrode;
  • the acoustic signal is converted into an analog signal based on one of an inverted bias voltage obtained by inverting the polarity of the bias voltage, the bias voltage, or a voltage between the inverted bias voltage and the bias voltage, and the polarity of the analog signal
  • Inverted analog signals may be generated, and the analog signal and the inverted analog signal may be applied to the two vibrating electrodes, respectively.
  • the present invention is characterized by comprising the above-described capacitance-type sound wave generator and configured to be able to generate sound waves in the audible range by the vibration of the two vibration electrodes by the acoustic signal input means.
  • a capacitive speaker may be used. According to this, it is possible to provide a highly reliable electrostatic capacity type speaker that can be mounted on a mobile device or a wearable device in which both power consumption and speaker size are restricted and pull-in does not occur.
  • the present invention it is possible to suppress the occurrence of pull-in in the capacitive sound wave generator and improve the reliability of the capacitive sound wave generator.
  • FIG. 1 shows a schematic diagram of a capacitive speaker 10 configured to be able to generate audible sound waves as an example of a capacitive sound wave generator to which the present invention is to be applied.
  • the vibrating body 12 and the vibrating electrode 13 are arranged as two vibrating electrodes so as to sandwich the fixed electrode 11.
  • the vibrating body 12 and the vibrating electrode 13 are the same as the fixed electrode 11. It is connected by the connecting member 14 through the through hole 11a.
  • the end of the fixed electrode 11 and the end of the vibrating body 12 are fixed, and the end of the vibrating electrode 13 is free. As shown in FIG.
  • the capacitance type speaker 10 applies a voltage to the vibrating body 12 in a state where a voltage is applied to the fixed electrode 11 and the fixed electrode 11 is negatively charged.
  • an electric signal having a polarity opposite to that of the fixed electrode 11 to the vibrating body 12 and positively charging it, an electrostatic attractive force is generated between the vibrating body 12 and the fixed electrode 11, and the vibrating body 12 is moved to the fixed electrode 11 side. To deform.
  • a voltage is applied to the vibrating electrode 13, and an electric signal having a polarity opposite to that of the fixed electrode 11 is sent to the vibrating electrode 13 so as to be positively charged.
  • An electrostatic attractive force is applied between the electrode 13 and the fixed electrode 11 to move the vibration electrode 13 to the fixed electrode 11 side.
  • the vibrating body 12 and the vibrating electrode 13 are coupled by the connecting member 14, the vibrating body 12 and the vibrating electrode 13 move in the same direction.
  • the vibrating body 12 is deformed to the opposite side to the fixed electrode 11.
  • the vibrating body 12 and the vibrating electrode 13 are disposed so as to sandwich the fixed electrode 11, and the vibrating body 12 and the vibrating electrode 13 disposed on the outside vibrate. Therefore, it is not necessary to provide a sound hole in any of the fixed electrode 11, the vibrating body 12, and the vibrating electrode 13. As a result, dust, water, moisture, and the like are placed between the fixed electrode 11 and the vibrating body 12 or the vibrating electrode 13 as compared with a conventional capacitive speaker in which a sound hole is provided in each outer fixed electrode. Hard to invade. For this reason, it can suppress that a foreign material adheres to the vibrating body 12, the vibrating electrode 13, and the fixed electrode 11, and generation
  • the through hole 11 a provided in the fixed electrode 11 is used only for passing the connection member 14, and therefore, compared to the sound hole for passing sound waves, the fixed electrode 11.
  • the ratio with respect to the surface area can be reduced. For this reason, even when the through hole 11a is provided, the amount of decrease in electrostatic force due to the through hole 11a is small.
  • the vibrating body 12 and the vibrating electrode 13 are disposed outside the fixed electrode 11, the waveform of the capacitive speaker 10 is disturbed by interference due to the sound wave output from the vibrating body 12 or the vibrating electrode 13. It can be propagated to the outside without increasing the sound quality.
  • a voltage is applied between the fixed electrode 11 and the vibrating body 12 or the vibrating electrode 13, and the vibrating body 12 and the vibrating electrode 13 are vibrated by the generated electrostatic force. By this vibration, air is vibrated to generate sound waves.
  • Such a mechanism for working by electrostatic force is also called an electrostatic actuator, and is used in various devices in addition to the capacitive speaker 10.
  • the vibrating body 12 or the vibrating electrode 13 collides with the opposing fixed electrode 11, and a strong electrostatic attraction is acting on the vibrating body 12 or the vibrating electrode 13, so that the vibrating body 12 or the vibrating electrode 13 contacts the fixed electrode 11.
  • the vibrating body 12 or the vibrating electrode 13 may be damaged due to sticking or an impact at the time of collision. Therefore, it is necessary to prevent pull-in when using an electrostatic actuator.
  • the interval between the vibrating body 12 or the vibrating electrode 13 and the fixed electrode 11 is set to be three times the vibration displacement of the vibrating body 12 or the vibrating electrode 13. It was necessary to set above.
  • the size and vibration displacement of the vibration electrode necessary for obtaining a sound pressure of 80 dB at a distance of 1 cm from the capacitive speaker 10 are as follows, for example. 1. Diameter of vibration electrode and fixed electrode: 4 mm 2. Vibrating electrode thickness / Young's modulus: 5 ⁇ m / 2.8 GPa 3. Displacement of vibrating electrode: 27 ⁇ m
  • the dielectric 15 is completely different in technical significance from a stopper or a spacer for preventing the vibrating body 12 and the vibrating electrode 13 from colliding with the fixed electrode 11.
  • the vibrating body 12 or the vibrating electrode 13 can be prevented from colliding with the fixed electrode 11, This is because it may be difficult for the vibrating body 12 or the vibrating electrode 13 to adhere to the dielectric 15 or behave stably in the space between the dielectric 15.
  • the vibrating body 12 or the vibrating electrode 13 is It has become possible to suppress sticking to the dielectric 15 and unstable operation.
  • the dielectric 15 is provided over the entire surface on both sides of the fixed electrode 11, but the dielectric 15 is not necessarily provided over the entire surface of both surfaces of the fixed electrode 11. You may provide in the one part area
  • the vibration body 12 may be provided only in the central portion where the displacement of the vibration body 12 becomes larger.
  • the fixed electrode 11 is provided with the single through hole 11a, and the vibration member 12 and the vibration electrode 13 are connected by the single connection member 14. Of course, a plurality of holes 11a and connecting members 14 may be provided.
  • the capacitive speaker system 20 including the capacitive speaker 10 and the acoustic signal input device 16 as acoustic signal input means in the present embodiment will be described.
  • the capacitive speaker system 20 includes the capacitive speaker 10 including the fixed electrode 11, the vibrating body 12, the vibrating electrode 13, the connection member 14, and the dielectric 15, and the acoustic signal input device 16. ing.
  • the fixed electrode 11 has, for example, a disk shape, and is provided with a through hole 11a provided through the center in the thickness direction.
  • the vibrating body 12 has a thin disk shape with a diameter smaller than that of the fixed electrode 11, for example.
  • the vibrating body 12 is disposed so as to face the fixed electrode 11.
  • the vibrating electrode 13 has a disk shape having the same diameter and thickness as the vibrating body 12, and is disposed so as to face the fixed electrode 11 on the side opposite to the vibrating body 12 with respect to the fixed electrode 11. .
  • the connecting member 14 has an elongated rod shape, and connects the vibrating body 12 and the vibrating electrode 13 through the through hole 11 a of the fixed electrode 11. Both ends of the connecting member 14 are fixed to the central portion of the vibrating body 12 and the central portion of the vibrating electrode 13, respectively. Thereby, the vibrating body 12 and the vibrating electrode 13 can vibrate in the thickness direction with respect to the fixed electrode 11. At that time, the vibrating body 12 and the vibrating electrode 13 are moved by the same distance in the same direction by the connecting member 14 and are vibrated simultaneously.
  • the acoustic signal input device 16 has a bias generator 31 and a voltage converter 32.
  • the bias generator 31 generates positive and negative bias voltages and supplies the positive bias voltage to the fixed electrode 11.
  • the bias generator 31 supplies a negative bias voltage to the voltage converter 32.
  • the voltage conversion unit 32 receives an acoustic signal from the acoustic input terminal 32a, and uses the acoustic signal as a reference from a negative bias voltage supplied from the bias generation unit 31 as a positive voltage or bias potential higher than the bias potential. Convert to analog signal with low negative voltage.
  • the voltage conversion unit 32 supplies the converted analog signal to the vibrating body 12 and supplies an inverted signal obtained by inverting the polarity of the analog signal to the vibrating electrode 13.
  • the capacitive speaker 10 vibrates using the electrostatic force acting between the vibrating body 12 and the fixed electrode 11 and between the vibrating electrode 13 and the fixed electrode 11 in accordance with the principle described with reference to FIGS. 1 and 2.
  • the body 12 and the vibrating electrode 13 are vibrated to generate sound waves.
  • the bias generator 31 may supply the voltage converter 32 with a positive bias voltage or a voltage between the negative bias voltage and the positive bias voltage instead of the negative bias voltage.
  • the voltage conversion unit 32 uses the positive bias voltage supplied from the bias generation unit 31 or a voltage between the negative bias voltage and the positive bias voltage as a reference, or a voltage higher than that potential. You may make it convert into the analog signal of a low voltage.
  • FIG. 5 is a diagram schematically showing the relationship between the fixed electrode 11 and the vibrating body 12.
  • the fixed electrode 11 is represented as a rigid frame.
  • the vibrating body 12 is represented as a plate hung by a helical spring having a spring constant k.
  • FIG. 5A shows a case where no voltage is applied between the fixed electrode 11 and the vibrating body 12.
  • the vibrating body 12 is located at a distance d 0 from the fixed electrode 11. At this height, the weight of the plate and the spring force are in balance.
  • the vibrating body 12 is selected as an example of the vibrating electrode. However, the same description also applies to the vibrating electrode 13.
  • FIG. 5B shows a case where a relatively low voltage V 1 is applied between the fixed electrode 11 and the vibrating body 12.
  • V 1 a relatively low voltage
  • FIG. 5 (b) in this case, between the fixed electrode 11 and the vibrating body 12, the electrostatic attraction caused by the voltage V 1, the vibrating body 12 is pulled to the fixed electrode 11. Then, in balance with the spring force in the second balancing position lowered by x 1 from the balanced position.
  • FIG. 5C shows a case where a voltage V 2 higher than V 1 is applied between the fixed electrode 11 and the vibrating body 12.
  • FIG. 5 (c) between the fixed electrode 11 and the vibrating body 12, the electrostatic attraction caused by the voltage V 2, the vibrating body 12 is pulled to the fixed electrode 11, stuck on colliding End up.
  • FIG. 6 shows the relationship between the spring force Fs and the electrostatic attractive force Fe.
  • the solid line represents the spring force Fs
  • the solid curve represents the electrostatic attractive force Fe.
  • the electrostatic attractive force Fe and the spring force Fs are acting in opposite directions.
  • a broken line obtained by vertically inverting the spring force Fs is shown.
  • the electrostatic attractive force Fe exceeds the spring force Fs, and the vibrating body 12 further approaches the fixed electrode 11. Then, since the difference between the electrostatic attractive force Fe and the spring force Fs becomes larger, the vibrating body 12 approaches the fixed electrode 11 at an accelerated speed, and as a result, the vibrating body 12 collides with and adheres to the fixed electrode 11. .
  • the dielectric 15 is provided on the fixed electrode 11.
  • a voltage V is applied between the fixed electrode 11 and the vibrating body 12 to generate an electrostatic attractive force Fe between the electrodes, so that the vibrating body 12 moves by x and the spring force Fs.
  • the electrostatic force Fe acting on this system when balanced with is expressed as the following equation (1).
  • ⁇ 0 is the dielectric constant of vacuum
  • ⁇ is the dielectric constant of the space between the vibrating body 12 and the dielectric
  • ⁇ 1 is the dielectric constant of the dielectric 15.
  • S is the area of the fixed electrode 11, the vibrating body 12 and the dielectric 15
  • V is an applied voltage between the fixed electrode 11 and the vibrating body 12
  • g is a balanced position when there is no applied voltage (hereinafter also referred to as an initial position).
  • the distance between the vibrating body 12 and the dielectric 15, t 1 represents the thickness of the dielectric 15, and x represents the displacement of the vibrating body 12 from the initial position.
  • the dielectric 15 layer is formed on the fixed electrode 11 to suppress the occurrence of pull-in. More specifically, the peak shown in FIG. 8 is made to exist inside the dielectric 15, and the vibration body 12 can be stably operated in the movable range of the vibration body 12. For this purpose, the following equation (4) should be satisfied. Equation (4) is transformed into Equation (5). If Expression (5) is satisfied, as shown in FIG. 9, the peak on the left side of Expression (3) always exists in the dielectric 15, so that the intersection with the straight line on the right side of Expression (3) The balance point is not to reach the peak on the left side of Equation (3). Therefore, the pull-in state does not appear in the movable range (x ⁇ g) of the vibrating body 12, and a stable operation is performed.
  • the layer of the dielectric 15 of the present invention is completely different in operation and effect from the spacers and stoppers often used in the electrostatic actuator.
  • a spacer is provided in the air gap of the electrostatic actuator. This prevents the electrodes from sticking directly when a pull-in operating voltage is applied.
  • the dielectric constant and dimensions are not associated with the operation of the electrostatic actuator and do not suppress pull-in.
  • the material of the dielectric 15 for example, a photosensitive resin formed by dispersing an inorganic material in a polymer may be used.
  • examples of the inorganic material to be dispersed include high dielectric constant inorganic particles (e.g., about ⁇ 50) such as barium titanate.
  • a photoresist resin material having a dielectric constant of about 3 to 4 such as SU-8 may be used.
  • FIG. 10A shows an example of the relationship between the voltage V and the displacement of the vibrating body 12 when the present embodiment is not applied
  • FIG. 10B shows the case where the present embodiment is applied. In the vicinity of the pull-in voltage V 0 , the displacement of the vibrating body 12 increases rapidly.
  • the horizontal axis indicates x, that is, the position of the vibrating body 12.
  • the vertical axis represents the force acting on the vibrating body 12. More specifically, the straight line that increases in proportion to x is the absolute value of the spring force Fs.
  • the curve having a convex shape below is the electrostatic force Fe. 11 and 12, the left unhatched part indicates the movable region of the vibrating body 12, and the right hatched part indicates the inside of the dielectric 15.
  • a solid line indicates a portion where the dielectric 15 is provided, and a broken line indicates a portion where the dielectric 15 is not provided and is different from the case where the dielectric 15 is provided.
  • FIG. 11A shows a case where the applied voltage V is smaller than the pull-in voltage V 0 .
  • the electrostatic force Fe is generally small, and the balance point, which is the intersection of the straight line indicating the spring force Fs and the curve indicating the electrostatic force Fe, is in a place where x is relatively small in the movable region of the vibrating body 12. Existing. Therefore, even when the voltage V is applied, regardless of the presence or absence of the dielectric 15, the vibrating body 12 moves to the balance point and stabilizes, and pull-in does not occur.
  • FIG. 11B shows a case where the applied voltage V is equal to the pull-in voltage V 0 .
  • the curve indicating the electrostatic force Fe when the dielectric 15 is not provided is in contact with the straight line indicating the spring force Fs.
  • the curve indicating the electrostatic force Fe when the dielectric 15 is provided intersects with a straight line indicating the spring force Fs. In this case, when the dielectric 15 is not provided, a balance point exists, but the electrostatic force Fe is larger than the spring force Fs at a position other than the balance point, so that the operation of the vibrating body 12 becomes unstable. Pull-in is likely to occur.
  • the dielectric 15 when the dielectric 15 is provided, there is a balanced point at the intersection of the curve indicating the electrostatic force Fe and the straight line indicating the spring force Fs, and the operation of the vibrating body 12 is stable. In this case, since the vicinity of the surface of the dielectric 15 serves as a balance point, the vibrating body 12 may come into contact with the dielectric 15, but there is no inconvenience such as damage to the vibrating body 12 due to a collision.
  • FIG. 12A shows a case where the applied voltage V is greater than the pull-in voltage V 0 .
  • the curve indicating the electrostatic force Fe when the dielectric 15 is not provided does not touch the straight line indicating the spring force Fs. And pull-in occurs.
  • the vibrating body 12 may collide with the fixed electrode 11.
  • the curve indicating the electrostatic force Fe when the dielectric 15 is provided intersects the straight line indicating the spring force Fs, and there is still a balance point, and the operation of the vibrating body 12 is stable. Actually, since the balance point exists inside the dielectric 15, the vibrating body 12 may contact the dielectric 15, but the difference between the electrostatic force Fe and the spring force Fs is small. There will be no inconvenience such as damage.
  • the capacitive speaker 10 according to the present embodiment can be manufactured by the following semiconductor manufacturing process. That is, as shown in FIG. 13A, a silicon substrate 50 comprising silicon (Si) 51 having a thickness of 300 ⁇ m and insulating layers 52 and 53 of silicon oxide (SiO 2) having a thickness of 0.8 ⁇ m provided on both surfaces. On the other hand, as shown in FIG. 13B, the lower insulating layer 53 in the drawing is entirely removed by dry etching, and the upper insulating layer 52 in the drawing forms a contact hole 54 by photolithography and dry etching.
  • Si silicon oxide
  • a parylene vibrating film 55 that becomes the vibrating body 12 of the capacitive speaker 10 is formed on the insulating layer 52 in which the contact holes 54 are formed by a CVD (chemical vapor deposition) method.
  • CVD chemical vapor deposition
  • a Ti / Au bilayer film (Ti 0.3 ⁇ m / Au 1 ⁇ m) 56 is formed as an electrode on the back surface of the surface on which the parylene vibration film 55 is formed by sputtering.
  • a carbon thin film 57 having a thickness of 100 nm is formed on the parylene vibration film 55 by sputtering.
  • SU-8 (2000) is formed by a roll coating method, and a photolithography technique is used.
  • a SU-8 (2000) gap forming portion 58 having a height of 27 ⁇ m is formed around the parylene vibration film 55 in a band shape.
  • a diaphragm connecting portion 59 having a diameter of 0.5 mm and a height of 27 ⁇ m is formed in the central portion of the parylene vibrating membrane 55 to form the connecting member 14.
  • a P-type silicon 60 having a thickness of 200 ⁇ m and a resistivity of 1 to 50 ⁇ cm is prepared as the fixed electrode 11.
  • the dielectric layers 61 and 62 of SU-8 (2000) are formed to a thickness of 100 ⁇ m by the roll coating method so as to be the dielectric 15 on both sides.
  • slits (inner diameter 0.51 mm, width 50 ⁇ m) 63 and 64 for connecting the parylene vibration film 55 are formed in the dielectric layers 61 and 62 by a photolithography technique.
  • a Ti / Au bilayer film (Ti 0.3 ⁇ m / Au 1 ⁇ m) 65 is formed as an electrode on the silicon 60 by sputtering.
  • the gap forming portion 58 and the diaphragm connecting portion 59 and the silicon 60 for the fixed electrode 11 are pressurized through the dielectric layer 62 of SU-8 (2000). / Adhere by heating.
  • the silicon 60 for the fixed electrode 11 is through-etched along the slits of the dielectric layers 61 and 62 by an anisotropic dry etching technique.
  • the silicon 51 is bonded to the parylene vibrating film 55 so that the parylene vibrating film 55 that becomes the vibrating body 12 and the insulating layer 52 of silicon oxide (SiO 2) remain by the anisotropic dry etching technique.
  • a vibrating electrode unit 63 to be the other vibrating body 12 formed by the processes of FIGS. 13A to 14A is prepared.
  • FIG. 16A another vibrating electrode unit 63 and the silicon 60 for the fixed electrode 11 are bonded to each other by pressurization / heating through a dielectric layer 61 of SU-8 (2000).
  • the silicon 67 is subjected to parylene vibration so that the parylene vibration film 68 to be the vibrating body 12 and the insulating layer 66 of silicon oxide (SiO 2) remain by an anisotropic dry etching method.
  • the film 68 and the silicon oxide (SiO 2) insulating layer 66 are etched away into a circle having a diameter of 4 mm from the back side. Then, as shown in FIG.
  • the insulating layers 52 and 66 of silicon oxide (SiO 2) formed in contact with the parylene vibration films 55 and 68 are removed by a method of oxide film dry etching, and the electrostatic capacity in this embodiment is thus obtained.
  • the type speaker 10 is completed.
  • the capacitive speaker 10 is formed by such a semiconductor manufacturing process, the capacitive speaker 10 can be manufactured more easily and with high reliability.
  • the capacitive speaker 10 has been described as an example of the capacitive sound wave generator, but the present invention is a capacitive sound wave generator other than the capacitive speaker 10. It is also applicable to. For example, an ultrasonic generator or a low-frequency generator corresponds to this. Further, in this embodiment, it has been described that the capacitive speaker 10 is manufactured by the semiconductor manufacturing process shown in FIGS. 13 to 17, but the capacitive speaker 10 is limited to such a MEMS device. I can't. The present invention is also applicable to a capacitance type speaker other than the MEMS type manufactured in a larger and general assembly process.
  • a fixed electrode (11) having a plate-like shape and having one or a plurality of through-holes (11a) provided so as to penetrate in the thickness direction; It has a plate-like or film-like shape, and is arranged with the fixed electrode (11) sandwiched so as to face the fixed electrode (11), and at least the central part of the fixed electrode (11) is in the thickness direction
  • Two vibrating electrodes (12, 13) movably provided on the A connecting member (14) for connecting the two vibrating electrodes (12, 13) through the through hole (11a);
  • a dielectric layer (15) is provided in at least a part of the surface on both sides of the fixed electrode (11) facing the two vibrating electrodes (12, 13).
  • the capacitive sound wave generator according to claim 1 or 2 further comprising acoustic signal input means (16) for applying a voltage between the vibrating electrodes (12, 13).
  • acoustic signal input means (16) for applying a voltage between the vibrating electrodes (12, 13).
  • the at least one of the fixed electrode (11) and the two vibrating electrodes (12, 13) is fixed at the peripheral edge thereof, according to any one of claims 1 to 3, Capacitance type sound wave generator.
  • the acoustic signal input means (16) Applying a positive or negative bias voltage to the fixed electrode (11);
  • the acoustic signal is converted into an analog signal based on one of an inverted bias voltage obtained by inverting the polarity of the bias voltage, the bias voltage, or a voltage between the inverted bias voltage and the bias voltage, and the polarity of the analog signal 4.
  • Capacitance type sound wave generator is provided by inverting the analog signal, and the analog signal and the inverted analog signal are applied to the two vibrating electrodes (12, 13), respectively.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)

Abstract

La présente invention fournit une technologie qui permet d'améliorer la fiabilité d'un dispositif de génération d'ondes sonores électrostatiques en minimisant l'occurrence d'accrochage. Un dispositif de génération d'ondes sonores électrostatiques comprend : une électrode fixe (11) comprenant un trou traversant (11a) qui passe à travers elle dans la direction de l'épaisseur; deux électrodes vibrantes (12, 13) qui sont disposées de manière à faire face à l'électrode fixe (11) entre elles et qui sont mobiles par rapport à l'électrode fixe (11); et un élément de connexion (14) pour connecter les deux électrodes vibrantes (12, 13) via le trou traversant (11a). Une couche diélectrique (15) est disposée sur au moins une zone partielle sur les surfaces faisant face aux deux électrodes vibrantes (12, 13) des deux côtés de l'électrode fixe (11).
PCT/JP2019/010845 2018-03-15 2019-03-15 Dispositif de génération d'ondes sonores électrostatiques et haut-parleur électrostatique WO2019177150A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007318327A (ja) * 2006-05-24 2007-12-06 Yamaha Corp 静電型スピーカ
JP2012029290A (ja) * 2010-07-22 2012-02-09 Commissariat A L'energie Atomique & Aux Energies Alternatives Ｍｅｍｓタイプの圧力パルス発生器
JP2013201488A (ja) * 2012-03-23 2013-10-03 Yamaha Corp 静電型トランスデューサ
JP2017050709A (ja) * 2015-09-02 2017-03-09 ヤマハ株式会社 静電型スピーカ

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007318327A (ja) * 2006-05-24 2007-12-06 Yamaha Corp 静電型スピーカ
JP2012029290A (ja) * 2010-07-22 2012-02-09 Commissariat A L'energie Atomique & Aux Energies Alternatives Ｍｅｍｓタイプの圧力パルス発生器
JP2013201488A (ja) * 2012-03-23 2013-10-03 Yamaha Corp 静電型トランスデューサ
JP2017050709A (ja) * 2015-09-02 2017-03-09 ヤマハ株式会社 静電型スピーカ

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