TWI589162B - Piezoelectric electro-acoustic transducer - Google Patents

Description

Piezoelectric electroacoustic transducer

This case relates to a transducer, in particular, to a piezoelectric electroacoustic transducer.

Conventionally, the design principle of the piezoelectric earphone is to utilize the conversion characteristics of the electrical energy and the mechanical energy of the piezoelectric element, and to drive the flat piezoelectric element to be deformed under the driving of the alternating voltage, thereby actuating and attaching to the piezoelectric element. The elastic member, in turn, pushes the air to change the dense distribution of the air molecules, and the densely distributed gas molecules can transmit sound waves and generate sound pressure.

Another bone conduction earphone converts electrical energy into mechanical vibrations of different frequencies, allowing humans to hear sound through the human skull, the auditory nerve, and the auditory center of the brain. Such a bone conduction earphone can save a lot of steps of sound wave transmission, and the sound wave does not affect others due to diffusion in the air.

However, when a conventional piezoelectric earphone is used as a bone conduction sound, the vibration energy of the elastic member can partially generate hearing through bone conduction, but at the same time, the air is pushed to generate sound, that is, a part. The vibration energy is still leaked due to the air being trapped by the elastic members. This is something that bone conduction headphones do not want to happen.

Therefore, how to overcome the above problems is currently a person skilled in the art. Committed to the goal of research and development.

A piezoelectric electroacoustic transducer includes: a first elastic member having a curved portion bent at a first direction between two ends of the first elastic member at both ends in the longitudinal direction; and Defining two sides of the thickness; the second elastic member has a bending portion formed at both ends in the longitudinal direction and between the two ends of the second elastic member to be bent in a second direction opposite to the first direction, and The two ends of the second elastic member are respectively engaged with the two ends of the first elastic member, and the curved portion of the second elastic member is separated from the curved portion of the first elastic member by a distance; at least a first piezoelectric element attached to at least one side of the two faces of the first elastic member to have the same curvature as the first elastic member; and at least a second piezoelectric element attached to the first elastic member At least one side of the two sides of the second elastic member has the same curvature as the second elastic member, wherein the electrical signal is actuated when an electrical signal is supplied to the first and second piezoelectric elements The first and second piezoelectric elements respectively drive the first and second bombs Vibrates. In addition, the amplitude of the first elastic member vibrating in the first direction is greater than the amplitude of the vibration in the second direction, and the amplitude of the second elastic member vibrating in the second direction is greater than the amplitude of the vibration in the first direction, and The first direction is a direction away from the second elastic member, and the second direction is a direction away from the first elastic member.

In addition, the first piezoelectric element is attached to the two sides of the first elastic sheet adjacent to the second elastic piece, and the two sides of the second elastic piece are attached to the side of the first elastic piece. Having the second piezoelectric element and providing the same electrical signal to the first and second piezoelectric elements causes the first The elastic piece and the second elastic piece vibrate in the first direction at the same time or simultaneously vibrate in the second direction.

The piezoelectric electroacoustic transducer of the present invention further includes a carrier for carrying the first elastic member and the second elastic member engaged; and a buffer body disposed on the first elastic member and the second elastic member Between the carrier and the second elastic member, the first elastic member and the second elastic member are not in contact with the carrier; the carrier member includes a hollow box having an opening and a film covering the opening to the second elastic member and The second piezoelectric element is received in the hollow box, and the first elastic member and the first piezoelectric element are exposed to the opening, and the film covers the first elastic member exposing the opening to the first elasticity The piece provides pre-stress.

The piezoelectric electroacoustic transducer of the present invention further includes a third elastic member disposed between the first elastic member and the second elastic member, and at least a third piezoelectric element attached to the third elastic member, the first The three elastic members have two ends in the longitudinal direction and two sides for defining the thickness, and the two ends of the third elastic member, the two ends of the first elastic member and the two ends of the second elastic member are joined, and the elastic member At least one third piezoelectric element is attached to at least one of the two faces of the third elastic member.

The piezoelectric electroacoustic transducer of the present invention further includes a fourth elastic member disposed between the third elastic member and the second elastic member, and at least a fourth piezoelectric element attached to the fourth elastic member, the first The four elastic members have two ends in the longitudinal direction, a curved portion bent in the second direction between the two ends of the fourth elastic member, and two sides for defining the thickness, and the at least one fourth piezoelectric The component is attached to at least one of the two sides of the fourth elastic member, wherein the third elastic member has a shape formed between the two ends of the third elastic member a curved portion bent in a first direction, two ends of the fourth elastic member, two ends of the third elastic member, two ends of the second elastic member, and two ends of the first elastic member are engaged, and the first The curved portion of the four elastic members is separated from the curved portion of the third elastic member.

Furthermore, the piezoelectric electroacoustic transducer of the present invention is a piezoelectric bone conduction transducer.

21, 23, 25, 27‧‧‧ elastic parts

211, 231, 251, 271‧‧ ‧ bending

212, 232, 252, 272‧‧‧

21T, 23T, 25T, 27T, 21L, 23L‧‧‧

22, 24, 26, 28‧‧‧ Piezoelectric components

3‧‧‧ Carrier

31‧‧‧ empty box

310‧‧‧ openings

32‧‧‧film

4‧‧‧ buffer

A, B‧‧ direction

D‧‧‧Distance

T‧‧‧ thickness

1A and 1B are a perspective view and a side view of an embodiment of a piezoelectric electroacoustic transducer of the present invention; FIG. 2A is a schematic view of another embodiment of the piezoelectric electroacoustic transducer of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 3 is a schematic cross-sectional view showing an embodiment of a piezoelectric electroacoustic transducer of the present invention; FIG. 4A-4C is a view of the present invention; Comparative Example of Piezoelectric Electroacoustic Transducer and Test Results of Example 1; 5A-5C are Test Results of Embodiments 1, 2, 3 and 4 of Piezoelectric Electroacoustic Transducer of the Present Case 6A-6C is a test result diagram of Embodiments 1, 5, and 6 of the piezoelectric electroacoustic transducer of the present invention; and 7A-7C is an embodiment of the piezoelectric electroacoustic transducer of the present invention. Test results of 1, 7, 8, and 9.

The embodiments of the present invention are described below by way of specific embodiments, and those skilled in the art can readily appreciate the other advantages and advantages of the present disclosure. It is to be understood that the structure, the proportions, the size and the like of the drawings are only used in conjunction with the disclosure of the specification for the understanding and reading of those skilled in the art, and are not intended to limit the practice of the present invention. The qualifications are not technically meaningful. Any modification of the structure, change of the proportional relationship or adjustment of the size should not be affected by the effects of the case and the objectives that can be achieved. The technical content can be covered.

Referring to FIGS. 1A-1B, the piezoelectric electroacoustic transducer of the present invention mainly includes two elastic members 21 and 23, and two piezoelectric elements 22 and 24 attached to the respective elastic members 21 and 23, respectively.

The elastic member 21 has a curved portion 211 which is curved in the direction A and two ends 212 in the longitudinal direction, and may have a rectangular shape or another shape having a substantial aspect ratio of more than 1, such as an elliptical shape or the like. The elastic member 21 has a thickness T that can be defined by two opposing faces 21T, a length that can be defined by the two opposing faces 21L, and a width, and the length to width ratio of the length to the thickness is greater than one. It should be noted that the direction A is the direction away from the elastic member 23 on the normal line of the elastic member 21.

The elastic member 23 has a curved portion 231 which is curved in the direction B and two ends 232 in the longitudinal direction, and may have a rectangular shape or another shape having a substantial aspect ratio of more than 1, such as an elliptical shape or the like. The elastic member 23 has a thickness T that can be defined by two opposing faces 23T, a length that can be defined by the two opposing faces 23L, and a width, and the length to width ratio of the length to thickness is greater than one. It should be noted that the direction B is the direction in which the normal line of the elastic member 23 is away from the elastic member 21.

The elastic members 21 and 23 have the same structure, and may be a single-layer plate or a multi-layer composite plate, for example, a three-layer composite plate in which the upper and lower sides are zinc-copper alloy and the middle is sandwiched with a pressure-sensitive adhesive.

In addition, the two ends 212 of the elastic member 21 are respectively engaged with the two ends 232 of the elastic member 23, and the curved portion 211 of the elastic member 21 is separated from the curved portion 231 of the elastic member 23 by a distance D, in other words, the elastic members 21 and 23 The distance between the curved portions 211 and 231 is the largest, and the closer to both ends 212 of the elastic member 21 and the both ends 232 of the elastic member 23 are gradually smaller. Further, in the case where the elastic members 21 and 23 are both rectangular, the both faces 21L of the elastic member 21 can be engaged with the both faces 23L of the elastic members 23, respectively, to complete the combination of the elastic members 21 and 23. The bonding system may apply an adhesive to the both faces 21L of the elastic member 21 and the both faces 23L of the elastic member 23, and then bond the two to each other.

The piezoelectric element 22 is attached to one of the two faces 21T of the elastic member 21 and has the same curvature as the elastic member 21. The piezoelectric element 24 is attached to one of the two faces 21T of the elastic member 21 and has the same curvature as the elastic member 23. It should be noted that although the drawing shows that the elastic member 21 has the piezoelectric element 22 attached to only one surface 21T, the elastic member 23 has the piezoelectric element 24 attached to only one surface 23T, but in specific implementation, the two sides 21T of the elastic member 21 are specifically implemented. The piezoelectric element 22 can be attached, and the piezoelectric element 24 can be attached to both sides 23T of the elastic member 23. Further, the piezoelectric elements 22 and 24 are the same, and are, for example, piezoelectric ceramics, PVDF or piezoelectric composite brakes.

In addition, the curved elastic member and the piezoelectric element can be formed, for example, by applying a force to an originally curved elastic member to make it temporarily flat, and then placing it In a mold in which the inside is in a vacuum state, a flat piezoelectric element is attached to the flat elastic member, and then the vacuum state in the mold is released, so that the elastic member returns from a flat shape to a curved shape. Then, the piezoelectric element can have the same curvature as the curved elastic member.

Referring to FIG. 2A, in an embodiment, the piezoelectric electroacoustic transducer of the present invention may further include an elastic member 25 disposed between the elastic members 21 and 23 and a piezoelectric element 26 attached to the elastic member 25. . The elastic member 25 has two ends 252 in the longitudinal direction and two faces 25T for defining the thickness, and the elastic member 25 is joined to both ends 212 of the elastic member 21 and the both ends 231 of the elastic member 23 except for the both ends 252 thereof. Other portions are not in contact with the elastic members 21 and 23. The piezoelectric element 26 can be attached to at least one side of the two faces 25T of the elastic member 25. The elastic member 25 in this embodiment has a flat shape.

Referring to FIG. 2B, in still another embodiment, the piezoelectric electroacoustic transducer of the present invention may further include an elastic member 27 disposed between the elastic members 23 and 25 and a piezoelectric element attached to the elastic member 27. 28. The elastic member 27 has a bent portion 271 which is curved in the direction B, two ends 272 which are located in the longitudinal direction, and two faces 27T for defining the thickness, and the piezoelectric element 28 can be attached to at least one surface of the both faces 27T of the elastic member 27. Further, both ends 272 of the elastic member 27, both ends 252 of the elastic member 25, both ends 232 of the elastic member 23, and both ends 212 of the elastic member 21 are joined, and the elastic member 25 has a bent portion 257 which is bent toward the direction A. And the curved portion 271 of the elastic member 27 is separated from the curved portion 251 of the elastic member 25.

According to the first embodiment of FIG. 1A-2B, the piezoelectric electroacoustic transducer of the present invention mainly comprises elastic members 21 and 23 joined at both ends and piezoelectric elements respectively attached thereto The pieces 22 and 24, in the case of considering vibration or sound conduction, may be configured with one or more elastic members and one or more piezoelectric elements attached thereto between the elastic members 21 and 23. Further, when an elastic member is disposed, it may have a flat shape, and when a plurality of elastic members are disposed, an even number of elastic members having opposite bending directions are preferable.

Referring to FIG. 3, in another embodiment, the piezoelectric electroacoustic transducer of the present invention may include a carrier 3 for carrying the bonded elastic members 21 and 23 and the elastic members 21 and 23 and the carrier. 3 between the buffers 4. The cushioning body 4 is for making the joined elastic members 21 and 23 not in direct contact with the carrier 3, and generally has a viscosity to bond the both ends 212 of the elastic members 21 and the ends of the elastic members 23 The 232 is fixed to the carrier 3. The buffer body 4 is, for example, a UV fixing glue, a sensible gel, a silicone gel or a foam rubber body.

The carrier 3 may be a frame that supports the carriers of the joined elastic members 21 and 23, or a film 32 including a hollow box 31 having an opening 310 and a covering opening 310 as shown in FIG. The hollow box 31 can accommodate the elastic member 23 and the piezoelectric element 24 in the hollow box 31 and expose the elastic member 21 and the piezoelectric element 22 to the opening 310, and the film 32 has tension after being stretched to cover the opening 310. The elastic member 21 is exposed to provide a pre-stress to the elastic member 21 and the piezoelectric member 22, in other words, the film 32 having a horizontal tension is vertically applied to the curved portion 211 of the elastic member 21 to be supplied to the elastic member 21. The pre-stressing enables the elastic member 21 to achieve a better rebounding effect, and further increases the amplitude of the vibration in the direction A. In addition, the buffer body 4 may be disposed between the curved portion of the elastic body 23 and the bottom surface of the hollow box 31 to prevent the elastic body 23 from contacting the hollow box when vibrating.

When electrical signals are supplied to the piezoelectric elements 22 and 24, respectively, such as alternating current, the piezoelectric elements 22 and 24 are stretched by the actuation of the electrical signals, thereby causing the elastic members 21 and 23 to vibrate. Specifically, referring to FIGS. 1A-1B, when the piezoelectric element 22 is stretched, the elastic member 21 vibrates toward the direction B; when the piezoelectric element 22 contracts, the elastic member 21 vibrates toward the direction A; when the piezoelectric element 24 is stretched, the elastic member 23 vibrates in the direction A; and when the piezoelectric element 24 contracts, the elastic member 23 vibrates in the direction B. Of course, if the piezoelectric elements 22 and 24 are attached to different faces of the elastic members 21 and 23, the elastic members 21 and 23 may have different vibration modes as described above. Furthermore, since the elastic member 21 is structurally curved in the direction A, this hinders the expansion and contraction of the piezoelectric element 22, so that the elastic member 21 generates a large displacement amount and acceleration when vibrating in the direction A. The displacement amount and the acceleration when vibrating in the direction B are relatively small; similarly, since the elastic member 23 is structurally curved in the direction B, this hinders the expansion and contraction of the piezoelectric element 24, so the elastic member 23 is moving toward When the direction B vibrates, a large displacement amount and acceleration are generated, and the displacement amount and acceleration when vibrating in the direction A are relatively small.

In addition, the piezoelectric element 22 can be attached to the one side 21T of the elastic member 21 adjacent to the elastic member 23, and the piezoelectric element 24 can be attached to the one side 23T of the elastic member 23 adjacent to the elastic member 21, when the pair of piezoelectric members 22 and 24 When the same electrical signal is respectively provided, the elastic member 21 and the elastic member 23 can vibrate in the direction A or simultaneously in the direction B. Thereby, the elastic member 21 vibrates in the direction A so that the air molecules on the side of the direction B are distributed sparsely to generate a relative negative pressure, and the elastic member 23 vibrates in the direction A to push the air on the side of the direction A to make the air molecules more distributed. Dense to produce a relative positive pressure; or, elastic member 21 to the direction B The vibration causes the air on the side of the direction B to make the air molecules densely distributed to generate a relative positive pressure, and the elastic member 23 vibrates in the direction B so that the air molecules on the direction A side are sparsely distributed to generate a relative negative pressure. As a result, during the period in which the piezoelectric elements 22 and 24 receive the alternating current to actuate the elastic members 21 and 23, the air between the elastic members 21 and 23 is maintained substantially the same by such a positive and negative pressure cancellation. Air molecular density.

Therefore, a specific embodiment of the piezoelectric electroacoustic transducer of the present invention is a piezoelectric bone conduction transducer, and the elastic member 21 or 23 is used to contact the human skin to perform bone conduction sound, and the elastic members 21 and 23 are respectively in the direction. A and B have a large displacement and acceleration, so that the vibration applied to the bone can be strengthened to increase the intensity of the conducted sound. In addition, the elastic members 21 and 23 have a small amount of displacement in the direction B and the direction A, respectively. And the acceleration, so that the compression of the air between the elastic members 21 and 23 can be reduced, and the elastic members 21 and 23 are simultaneously vibrated in the same direction to cancel each other and squeeze the air between the elastic members 21 and 23. The pressure can maintain substantially the same air density, thereby reducing the probability of sound leakage through the air conduction, thereby significantly eliminating noise. Next, Table 1 and 4A-7C illustrate the separation distance of the two elastic members of the piezoelectric electroacoustic transducer of the present invention, the thickness of each elastic member, and the tension of the film and the displacement displacement of the elastic member, The relationship between vibration acceleration and leakage SPL. The test conditions of the comparative example and the examples 1-9 were as follows: a voltage of 10 Vrms was placed at 10 mm above the artificial ear, and the vibration displacement amount and acceleration of the central bending portion of the elastic member were measured by a laser range finder. In addition, the sound pressure was measured in the silent chamber, and the sound distance was set to 10 cm.

It should be noted that the piezoelectric electroacoustic transducers of Embodiments 1-9 are, for example, shown in FIG. 3, the two elastic members are curved and the curved portions are separated by a distance, and the two ends are joined to each other to be viscous. The buffer body is fixed in the hollow box; the two elastic members of the comparative example are flat, and the two ends are not joined but are respectively fixed in the hollow box by the viscous buffer body, and all the parts of the elastic members are Both are separated by the same distance. The size of the hollow box is 32 mm × 7 mm × 1.8 mm, the size of each piezoelectric element is 25 mm × 4 mm × 0.1 mm, the length and width of each elastic member is 30 mm × 5 mm, and the thickness of each elastic member, the distance between the two elastic members, The tension of the film is shown in Table 1.

Referring to Table 1 and FIG. 4A-4C, the piezoelectric electroacoustic transducer between the comparative example and the embodiment 1 differs only in the shape of the elastic member, as shown in FIG. 4A, the piezoelectric electroacoustic exchange of the embodiment 1. The starting frequency of the energy device is about 120Hz, and the average vibration displacement between the low frequency of 100~500Hz is about 37μm. In contrast, the piezoelectric electroacoustic transducer of the comparative example has a starting frequency of about 230Hz, and the low frequency is 100~500Hz. The average vibrational displacement between them was about 25 μm, which was significantly smaller than that of Example 1. As shown in Fig. 4B, the oscillating acceleration of the piezoelectric electroacoustic transducer of Embodiment 1 occurs at a frequency of about 120 Hz, exceeding 0.9 m/s ² , and an average acceleration of about 0.96 m/s at a low frequency of 100 to 500 Hz. ² ; In contrast, the piezoelectric electroacoustic transducer of the comparative example exhibits a oscillating acceleration at a frequency of about 230 Hz, about 0.7 m/s ² , and an average acceleration of about 0.6 m/s ² at a low frequency of 100 to 500 Hz, which is significantly more practical. Example 1 is small. As shown in FIG. 4C, the piezoelectric electroacoustic transducer of the first embodiment has a starting frequency of about 120-130 Hz, a sound pressure level of about 45 dB between low frequencies of 100 and 500 Hz, and gradually increases to a low frequency of 50 dB. In contrast, the piezoelectric electroacoustic transducer of the comparative example has a starting frequency of about 230 Hz, a sound pressure level of about 53 dB between low frequencies of 100 to 500 Hz, and a gradually increasing low frequency of 68 dB, which is significantly larger than that of the first embodiment.

As can be seen from the 4A-4C figure, the curved elastic member can provide a larger displacement amount and acceleration and has a smaller SPL than the flat elastic member, and the piezoelectric electroacoustic transducer of the first embodiment is shown. The second elastic member pushes the air inwardly to have a smaller amplitude and the outwardly vibrating bone has a larger amplitude. It should be noted that the inward direction is the direction in which the two elastic members are close to each other, and the outward direction is the direction in which the two elastic members are apart from each other. In contrast, since the two elastic members of the piezoelectric electroacoustic transducer of the comparative example are in the form of a flat plate, deformation of the piezoelectric element attached thereto cannot be hindered, so it is difficult to suppress the amplitude of the inward pushing air, resulting in a larger SPL.

Therefore, the piezoelectric electroacoustic transducer of the present invention can mainly convert the received electric energy into the vibration energy transmitted through the bone, and only a few of them convert into the vibration energy of the air conduction compared with the comparative example.

Referring to Table 1 and Figures 5A-5C, the effects of the separation distances of the two elastic members of 1 mm, 2 mm, 3 m, and 4 mm on the vibration displacement, acceleration, and sound pressure level are discussed. As shown in FIG. 5A, the piezoelectric electroacoustic transducers of Embodiments 1, 2, 3, and 4 have a starting frequency of about 120-130 Hz, and the displacement amount curves of the embodiments are similar, but the embodiment thereof The vibration displacement amount of 1 (separation distance 2 mm) and 3 (separation distance 3 mm) is large, up to 37 μm or more, and the vibration displacement amounts of Example 2 (separation distance 1 mm) and 4 (separation distance 4 mm) are small. As shown in FIG. 5B, the acceleration curves of the respective embodiments are similar in distribution, but the accelerations of Embodiment 1 (separation distance 2 mm) and 3 (separation distance 3 mm) are large, and can reach 1 m/s ² or more, and the embodiment The accelerations of 2 (separation distance 1 mm) and 4 (separation distance 4 mm) are small. It can be seen from Fig. 5A-5B that the displacement amount of the elastic member has a corresponding relationship with the acceleration. Next, as shown in FIG. 5C, the curve of the sound pressure level of each embodiment is substantially smooth, the starting frequency is about 120-130 Hz, and the average SPL is reduced from 60 db at 100 Hz to 45 db at high frequency. It has been extremely quiet, especially the SPL of Example 1 (separation distance 2 mm) and 3 (separation distance 3 mm) is smaller.

As can be seen from Figures 5A-5C, the separation distance of the curved portions of the two elastic members has a preferred range. The separation distance of the two elastic members is more understood as the degree of curvature of the elastic member. For example, the bending degree is small when the distance is 1 mm, and the bending degree is large when the distance is 4 mm. In addition, the elastic member whose curvature is too small can provide a small prestress to the piezoelectric element, and the elastic member whose curvature is excessively large becomes easy to become Non-linear, so the separation distance of the curved portions of the two elastic members is preferably 1 mm to 4 mm.

Referring to Table 1 and Figures 6A-6C, the effects of film tensions of 10N, 15N, and 20N on vibration displacement, acceleration, and sound pressure levels are discussed. As shown in FIGS. 6A and 6B, the oscillation frequency in each embodiment is slightly changed, and the piezoelectric electroacoustic transducer of Embodiment 1 (tension is 15N) has a large vibration displacement amount and acceleration, and Embodiment 6 (Tension is 20N), and Example 5 (tension is 10N) is the smallest. As can be seen from Fig. 6C, each embodiment exhibits a lower SPL at frequencies of 100-10000 Hz.

According to Fig. 6A-6C, the appropriate film tension can contribute to the springback of the elastic member, and the too small film tension can impart a small prestress to the elastomer, but the excessive film tension can significantly change the piezoelectric voltage. In addition to the starting frequency of the energy device, it may also lead to an increase in the leakage SPL. Therefore, the preferred range of the tension of the film is 10N-20N.

Referring to Table 1 and Figures 7A-7C, the effects of the thickness of the elastic members of 0.1 mm, 0.15 mm, 0.2 mm, and 0.25 mm on the vibration displacement, acceleration, and leakage sound pressure are investigated. As shown in Figures 7A and 7B, the piezoelectric voltage transducer of Embodiment 7 (thickness 0.1 mm) can achieve a lower starting frequency, about 50 Hz, where the displacement and acceleration are about 28 μm and 0.7, respectively. m/s ² , the vibration frequency of the piezoelectric voltage transducer of the embodiment 1 (thickness 0.15mm) is increased to about 120-130 Hz, the average vibration displacement between the low frequency 100~500 Hz is about 37 μm, and the average acceleration is about 0.96. m/s ² . As shown in Fig. 7C, the embodiments exhibit a lower SPL at frequencies of 100-10000 Hz.

According to the figure 7A-7C, it can be controlled by adjusting the thickness of the elastic member. The starting frequency and vibration strength of the elastic member, the excessively thick elastic member may cause an excessive SPL due to too much rigidity. Therefore, the thickness of the elastic member is preferably in the range of 0.1 mm to 0.25 mm.

In summary, the piezoelectric electroacoustic transducer of the present invention mainly comprises two elastic members which are joined at both ends and the bending portions are separated, and the two piezoelectric elements respectively attached to the two elastic members are covered. The film on one of the elastic members has the combined effect of the stress exerted by the piezoelectric element being actuated by the electric signal, the elastic force of the curved elastic member, and the prestress of the film, so that the two elastic members are facing outward. The direction has a large vibration displacement and acceleration, which can improve the intensity of sound transmission through the bone, and has a small vibration displacement and acceleration in the inward direction, which can reduce the air extrusion inside, and the two elastic members The pressure generated by the air inside the vibration can cancel each other, so that the sound leakage caused by the air conduction is greatly reduced, and the leakage sound pressure is reduced. Compared to traditional bone conduction headphones, the noise is significantly reduced.

The above-described embodiments are merely illustrative of the effects of the present invention, and are not intended to limit the scope of the present invention, and those skilled in the art can modify and modify the above-described embodiments without departing from the spirit and scope of the present invention. Moreover, the number of structures in the above-described embodiments is merely illustrative and is not intended to limit the present invention. Therefore, the scope of protection of the rights in this case should be listed in the scope of the patent application mentioned later.

21, 23‧‧‧ elastic parts

22, 24‧‧‧ Piezoelectric components

212, 232‧‧‧

Claims (10)

A piezoelectric electroacoustic transducer includes: a first elastic member having a curved portion bent at a first direction between two ends of the first elastic member at both ends in the longitudinal direction; and Defining two sides of the thickness; the second elastic member has a bending portion formed at both ends in the longitudinal direction and between the two ends of the second elastic member to be bent in a second direction opposite to the first direction, and The two ends of the second elastic member are respectively engaged with the two ends of the first elastic member, and the curved portion of the second elastic member is separated from the curved portion of the first elastic member by a distance; at least a first piezoelectric element attached to at least one side of the two faces of the first elastic member to have the same curvature as the first elastic member; and at least a second piezoelectric element attached to the first elastic member At least one side of the two sides of the second elastic member has the same curvature as the second elastic member; wherein when the electrical signal is supplied to the first and second piezoelectric elements, the electrical signal is actuated The first and second piezoelectric elements respectively drive the first and second bombs Vibrates. The piezoelectric electroacoustic transducer of claim 1, wherein the amplitude of the first elastic member vibrating in the first direction is greater than the amplitude of the vibration in the second direction, and the second elastic member faces the first The amplitude of the vibration in the two directions is greater than the amplitude of the vibration in the first direction, and the first direction is away from the direction of the second elastic member, and the second direction is away from the first The direction of an elastic member. The piezoelectric electroacoustic transducer of claim 1, wherein the first elastic element is attached to the one side of the first elastic piece adjacent to the second elastic piece, the second elastic Attaching the second piezoelectric element to one side of the two sides adjacent to the first elastic piece, and providing the same electrical signal to the first and second piezoelectric elements, the first elastic piece and the first elastic piece are The second elastic piece vibrates simultaneously in the first direction or simultaneously in the second direction. The piezoelectric electroacoustic transducer of claim 1, further comprising a third elastic member disposed between the first elastic member and the second elastic member and at least one attached to the third elastic member a third piezoelectric element having two ends in a length direction and two sides for defining a thickness, both ends of the third elastic member, both ends of the first elastic member, and the second elastic member The two ends are joined, and the at least one third piezoelectric element is attached to at least one of the two faces of the third elastic member. The piezoelectric electroacoustic transducer of claim 4, further comprising a fourth elastic member disposed between the third elastic member and the second elastic member and at least one attached to the fourth elastic member a fourth piezoelectric element having two ends in the longitudinal direction, a curved portion bent in the second direction between the both ends of the fourth elastic member, and two sides defining the thickness, and The at least one fourth piezoelectric element is attached to at least one of the two faces of the fourth elastic member, wherein the third elastic member has a shape formed between the two ends of the third elastic member and bent toward the first direction a curved portion, two ends of the fourth elastic member, the third elasticity The two ends of the member, the two ends of the second elastic member and the two ends of the first elastic member are engaged, and the curved portion of the fourth elastic member is separated from the curved portion of the third elastic member. The piezoelectric electroacoustic transducer of claim 1, further comprising: a carrier for carrying the first elastic member and the second elastic member; and a buffer body disposed at the first And between the elastic member and the second elastic member and the carrier member, so that the first elastic member and the second elastic member do not contact the carrier member. The piezoelectric electroacoustic transducer of claim 6, wherein the carrier comprises a hollow box having an opening and a film covering the opening to accommodate the second elastic member and the second piezoelectric element The first elastic member and the first piezoelectric element are exposed in the opening, and the film covers the first elastic member exposing the opening to provide the first elastic member and the second elastic member Prestressed. The piezoelectric electroacoustic transducer of claim 7, wherein the thickness of the first elastic member and the thickness of the second elastic member are between 0.1 mm and 0.25 mm, and the distance is Between 1 mm and 4 mm, the prestressing force is between 10N and 15N, and adjusting the thickness of the first elastic member and the thickness of the second elastic member can change the first elastic member and the second elastic portion. The starting frequency and the vibration intensity of the piece are adjusted, and the pre-stress provided by the diaphragm can change the starting frequency of the first elastic member and the second elastic member. A piezoelectric electroacoustic transducer according to claim 1, wherein The first elastic member and the second elastic member each have a length and a width, and an aspect ratio of the length to the width is greater than 1. The piezoelectric electroacoustic transducer of claim 1, wherein the piezoelectric electroacoustic transducer is a piezoelectric bone conduction transducer.