KR101847164B1 - Sound output apparatus - Google Patents

Abstract

The present invention provides a portable terminal comprising: a housing having a housing space therein; A first sound output section at least partially provided in the housing; And a second sound output unit spaced apart from the first sound output unit by a predetermined distance, wherein one of the first and second sound output units includes a piezoelectric element and a vibration element, and the piezoelectric element includes a plurality of piezoelectric Layer, and the piezoelectric layer has a thickness of less than 15 [mu] m.

Description

[0001] The present invention relates to a sound output apparatus,

The present invention relates to an acoustic output apparatus, and more particularly to an acoustic output apparatus capable of improving output characteristics of an audible frequency band including a low-frequency band and a high-frequency band.

Generally, a piezoelectric element is a device having a characteristic capable of changing electric energy and mechanical energy with each other. That is, a piezoelectric element generates a voltage when a pressure is applied (a piezoelectric effect), and when a voltage is applied, the volume or length of the piezoelectric element is increased or decreased due to a change in pressure inside the piezoelectric element. The piezoelectric element is composed of a piezoelectric layer and an electrode provided on the piezoelectric layer, and the pressure changes according to the voltage applied to the piezoelectric layer through the electrode.

By using such a piezoelectric element, various components such as a piezoelectric speaker and a vibration device can be manufactured. In the meantime, the piezoelectric speaker is a part that generates a sound of a desired frequency band by acoustically converting the mechanical movement of the piezoelectric element by the diaphragm. Such a piezoelectric speaker is advantageous in that it is thin, light and consumes less power than a conventional dynamic speaker, and thus can be used in electronic devices such as a smart phone requiring a compact, thin and light weight. However, the piezoelectric speaker has a strong high-pitched sound and a low-pitched sound, so that it can not listen to music for a long time.

On the other hand, dynamic speakers are widely used for music reproduction. The dynamic speaker uses the principle that when a voice signal current is supplied to a voice coil in a magnetic field of a magnet, a mechanical force acts on the voice coil according to the intensity of the current to cause motion. However, such a dynamic speaker is suitable for realizing a low-frequency sound, but is relatively weak to implement a high-frequency sound, and thus has a limitation in providing a high-quality sound.

Korean Patent Publication No. 2014-0083860 Korea Patent No. 10-1212705

The present invention provides an acoustic output device having both the advantages of a piezoelectric speaker and the advantages of a dynamic speaker.

The present invention provides an acoustic output device capable of improving both bass and treble characteristics.

According to an aspect of the present invention, there is provided an acoustic output apparatus comprising: a housing having an accommodation space therein; A first sound output section at least partially provided in the housing; And a second sound output unit spaced apart from the first sound output unit by a predetermined distance, wherein one of the first and second sound output units includes a piezoelectric element and a vibration element, and the piezoelectric element includes a plurality of piezoelectric Wherein the plurality of piezoelectric layers comprise a non-polarized piezoelectric layer and a plurality of polarized piezoelectric layers provided at upper and lower portions of the non-polarized piezoelectric layer, And the vibrating element is formed of a polymer-based or pulp-based material.

The vibration element has a Young's modulus of 1 MP to 10 GPa.

And at least one emission hole formed in a predetermined region of the housing.

A spacing space is provided between the first and second sound output sections, and at least a part of the emission hole is formed corresponding to the spacing space.

The housing includes a first member and at least one second member provided to surround the first member, and the discharge hole is formed in a predetermined region of the second member.

The first member is provided in a plate shape having a predetermined thickness to separate the first and second sound output sections.

The discharge hole is formed to correspond to a space between the first member and the first sound output section.

The first and second sound output units are simultaneously driven by signals of the same level.

The first and second sound output units are driven with a voltage of 0.1 V to 5.0 V.

And an opening formed in the vibration element.

The acoustic output device according to embodiments of the present invention is provided with a dynamic speaker and a piezoelectric speaker spaced apart from each other by a predetermined distance in the housing. Therefore, by providing a dynamic speaker having excellent bass characteristics and a piezoelectric speaker having excellent high-tone characteristics in one housing, it is possible to improve acoustic characteristics in an audible frequency band. In addition, by providing a separation member in the housing, the dynamic speaker and the piezoelectric speaker are separated from each other so that the sound output from the dynamic speaker and the piezoelectric speaker can be mixed outside the housing without mixing in the housing, thereby further improving sound quality. Meanwhile, the sound output apparatus of the present invention can be implemented as a speaker, an earphone, or the like.

1 is an exploded perspective view of an audio output apparatus according to a first embodiment of the present invention;
2 is an exploded perspective view of an audio output device according to a first embodiment of the present invention;
3 is an assembled sectional view of an acousto-output device according to a first embodiment of the present invention.
4 is an exploded perspective view of an audio output device according to a second embodiment of the present invention;
5 is an exploded perspective view of an audio output apparatus according to the second and third embodiments of the present invention;
6 is an exploded perspective view of an audio output device according to a third embodiment of the present invention;
7 is an assembled sectional view of an acousto-output device according to a third embodiment of the present invention.
8 is a characteristic graph of a dynamic speaker, a piezoelectric speaker and an acoustic output device according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of other various forms of implementation, and that these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know completely.

FIG. 1 is an exploded perspective view of an audio output apparatus according to a first embodiment of the present invention, FIG. 2 is an assembled perspective view, and FIG. 3 is an assembled sectional view.

1, 2 and 3, the acoustic output apparatus according to the first embodiment of the present invention includes a first acoustic output unit 100, a second acoustic output unit 100 provided on the first acoustic output unit 100, An output unit 200, and a housing 300 that accommodates the first and second sound output units 100 and 200. That is, the first and second sound output units 100 and 200 may be provided in the housing 300 at predetermined intervals. The first acoustic output unit 100 includes a voice coil 140 and a diaphragm 150. The first acoustic output unit 100 vibrates according to a change in current of the voice coil 140 and uses the same to vibrate the diaphragm 150 to output sound And may include dynamic speakers. The second acoustic output unit 200 includes a piezoelectric speaker 210 including a piezoelectric element 210 and a vibration element 220 to acoustically convert the mechanical movement of the piezoelectric element 210 by the vibration element 220 can do.

One. 1st  The sound output section

The first sound output unit 100 may be provided in a substantially circular shape having a predetermined thickness. The first sound output unit 100 includes a yoke 110 and a frame 115 on the inner side of which a housing space is provided, a magnet 120 provided in an accommodation space in the yoke 110, A voice coil 140 which is provided between the yoke 110 and the magnet 120 from the inside of the frame 115 and a voice coil 140 which is provided on the top of the plate 130 and whose edge is fixed to the frame 115 And a diaphragm 150 to which the voice coil 140 is fixed.

The yoke 110 has a predetermined height and is provided in a substantially circular shape. The frame 115 is provided on the upper side of the yoke 110 and has a predetermined height and is provided in a substantially circular shape. At this time, the height of the frame 150 may be higher than the height of the yoke 110, and the width of the frame 115 may be larger than the width of the yoke 110. Of course, the height of the frame 115 may be equal to or less than the height of the yoke 110. Here, the upper edge of the frame 115 can be received in the housing 300 in contact with at least one area of the housing 300. The magnet 120 and the plate 130 are accommodated in the yoke 110 and the voice coil 140 is accommodated in the frame 115. The diaphragm 150 covers the frame 115 And may be provided on the upper side thereof. The yoke 110 and the frame 115 guide the magnetic field formed by the magnet 120 toward the plate 130 and maximize the magnetic force by the magnet 120 to the voice coil 140.

The magnet 120 is fixed to the bottom surface of the yoke 110. That is, the lower surface of the magnet 120 is fixed in contact with the bottom surface of the yoke 110. The magnet 120 may be formed in a shape corresponding to the inner shape of the yoke 110. For example, the inside of the yoke 110 is provided in a substantially cylindrical shape, and the magnet 120 is provided in a substantially cylindrical shape. At this time, the height of the magnet 120 may be lower than or equal to the height of the yoke 110. The diameter of the magnet 120 may be smaller than the inner diameter of the yoke 110. Therefore, the magnet 120 may be provided on the inner side of the yoke 110 at a predetermined distance from the inner wall of the yoke 110.

The plate 130 is provided on the upper surface of the magnet 120. The plate 130 may have the same shape as the plane shape of the magnet 120. That is, the plate 130 may be provided in a circular plate shape having a predetermined thickness. Here, the plate 130 has a smaller diameter than the inner diameter of the yoke 110, and may have a diameter equal to or larger than the diameter of the magnet 120. Therefore, the outer side of the plate 130 may be spaced apart from the inner surface of the yoke 110 by a predetermined distance. The height of the magnet 120 and the plate 130 provided on the magnet 120 may be the same as the height of the yoke 110. That is, the plate 130 and the upper portion of the yoke 110 may be flush with each other. This plate 130 allows the magnetic force lines generated by the magnet 120 to be focused toward the voice coil 140 side.

The voice coil 140 is attached to the lower surface of the diaphragm 150 and may be provided between the yoke 110 and the magnet 120 from the inside of the frame 115. For example, the voice coil 140 is provided between the yoke 110 and the yoke 110 so as to surround the plate 130 and a part of the magnet 120, and the upper portion of the voice coil 140 is attached to the lower surface of the diaphragm 150. The voice coil 140 vibrates due to interference due to interference with a magnetic field formed by the magnet 120 by forming a magnetic field continuously changed by an input electrical signal while continuously changing.

The diaphragm 150 is fixed to the inside of the frame 115 so as to cover the upper side of the frame 115. In addition, the diaphragm 150 may be provided so that at least one area is convex. For example, the region corresponding to the central region of the frame 115 may be provided in the form of being the highest and lowering outwardly therefrom. That is, the diaphragm 150 may be formed in a convex shape that decreases from the area corresponding to the center of the magnet 120 and the plate 130 to the outside thereof. In addition, the voice coil 140 may be fixed to the lower side of the lowest region of the diaphragm 150.

The first sound output unit 100 moves the magnetic field generated from the magnet 120 to the lower yoke 110 through the plate 130 provided on the magnet 120 and then to the magnet 120 Constitute a closed circuit. A magnetic field moving to a space between the plate 130 and the lower yoke 110 is generated by applying a current to the voice coil 140 so that the voice coil 140 is magnetized by a voice coil 140 according to the magnetic polarity of the voice coil 140. [ The coil 140 is pulled or pushed out. That is, when the magnetic force polarity of the voice coil 140 is equal to the magnetic force polarity of the plate 130 and the yoke 110 on the lower side, the voice coil 140 is repelled to push the voice coil 140 to move the voice coil 140 forward, 130 and the lower yoke 110, the voice coil 140 is pulled back. When the voice coil 140 moves as described above, the diaphragm 150, to which the voice coil 140 is fixed, moves back and forth to vibrate the air to generate sound.

2. Second  The sound output section

The second acoustic output unit 200 may include a piezoelectric element 210 and a vibration element 220. The piezoelectric element 210 may be provided in a circular plate shape having a predetermined thickness, for example. Of course, the piezoelectric element 210 may be formed in various shapes such as a square, a rectangle, an ellipse, and a polygon as well as a circular shape. Such a piezoelectric element 210 may include a substrate and a piezoelectric layer formed on at least one surface of the substrate. For example, the piezoelectric element 210 may be formed as a bimorph type in which a piezoelectric layer is formed on both sides of a substrate, or a unimorph type in which a piezoelectric layer is formed on one side of the substrate. At least one layer of the piezoelectric layer may be laminated, and preferably, a plurality of piezoelectric layers may be laminated. In addition, electrodes may be formed on the upper and lower portions of the piezoelectric layer, respectively. That is, a plurality of piezoelectric layers and a plurality of electrodes are alternately stacked to realize the piezoelectric element 210. Here, the piezoelectric layer can be formed using, for example, PZT (Pb, Zr, Ti), NKN (Na, K, Nb), BNT (Bi, Na, Ti) Further, the piezoelectric layers can be polarized in different directions or in the same direction to be laminated. That is, when a plurality of piezoelectric layers are formed on one surface of the substrate, the piezoelectric layers may be alternately polarized in opposite directions or in the same direction. On the other hand, the substrate can be made of a material having characteristics such that vibration can be generated while maintaining a laminated structure of the piezoelectric layers. For example, metal, plastic, or the like can be used. However, the piezoelectric element 210 may not use a piezoelectric layer and a substrate. For example, a plurality of piezoelectric layers polarized in different directions may be stacked on upper and lower portions of the piezoelectric layer, The piezoelectric element 210 can be formed. An electrode pattern (not shown) to which a driving signal is applied may be formed on one surface of the piezoelectric element 210. At least two electrode patterns may be spaced apart from each other, and may be connected to a connection terminal (not shown) to receive sound signals from an electronic device, for example, an auxiliary mobile device.

The vibration element 220 is provided in a substantially circular plate shape and may be provided larger than the piezoelectric element 210. In addition, the vibrating element 220 may have an opening at the center and a piezoelectric element 210 on the opening. The piezoelectric element 210 may be adhered to the upper surface of the vibration element 220 with an adhesive. The vibration element 220 may be a polymer-based material or a pulp-based material. For example, the vibration element 220 can use a resin film, and a material having a Young's modulus of 1 MPa to 10 GPa and a large loss coefficient, such as an ethylene propylene rubber type or styrene butadiene rubber type, can be used. In addition, the lower edge of the vibrating element 220 can be brought into contact with the inner surface of the housing 300. That is, the vibration element 220 and the piezoelectric element 210 bonded to the central portion of the vibration element 220 may be provided in the space inside the housing 300. The second sound output unit 200 is driven according to a predetermined signal, and can output sound with high sound quality.

Meanwhile, a coating layer (not shown) may be further formed on at least a part of the second sound output unit 200. The coating layer may be formed using a waterproof material such as parylene. Parylene is formed on the upper surface and the side surface of the piezoelectric element 210 and the upper surface and the side surface of the vibration element 220 exposed by the piezoelectric element 210 in a state where the piezoelectric element 210 is bonded on the vibration element 220 . That is, the parylene may be formed on the upper surface and side surfaces of the piezoelectric element 210 and the vibration element 220. The parylene may be formed on the upper surface and the side surface of the piezoelectric element 210 and the upper surface, the side surface and the lower surface of the vibration element 220 in a state where the piezoelectric element 210 is bonded on the vibration element 220. That is, the parylene may be formed on the upper surface, the side surface, and the lower surface of the piezoelectric element 210 and the vibration element 220. When the piezoelectric element 210 is provided on the opening formed in the central portion of the vibration element 220, the parylene is formed on the lower surface exposed by the upper surface, the side surface, and the opening of the piezoelectric element, The side surface and the bottom surface, respectively. By forming the parylene in at least one surface of the piezoelectric element 210 and the vibration element 220, it is possible to prevent moisture penetration into the second acoustic output unit 200 and to prevent oxidation. In addition, it is possible to improve the knitting vibration generated by using the vibration element 220 made of a thin material such as a polymer, and to improve the response speed by increasing the hardness of the vibration element 220 to relax the deep sound characteristics, . The resonance frequency can be adjusted according to the coating thickness of parylene, so that improvement of the sound pressure can be controlled. The parylene may be coated only on the piezoelectric element 210. The parylene may be coated on the upper surface, the side surface and the lower surface of the piezoelectric element 210 and connected to the piezoelectric element 210 to supply power to the piezoelectric element 210. [ Or may be coated on the FPCB. Since parylene is formed in the piezoelectric element 210, moisture penetration of the piezoelectric element can be prevented and oxidation can be prevented. Also, the resonance frequency can be adjusted by adjusting the thickness of the formation. On the other hand, when parylene is formed on the FPCB, the abnormal noise generated in the FPCB, the solder, and the device junction may be improved. The parylene may be coated with a different thickness depending on the material and characteristics of the piezoelectric element 210 or the vibration element 220. The parylene may be formed to be thinner than the thickness of the piezoelectric element 210 or the vibration element 220, For example, 0.1 占 퐉 to 10 占 퐉. In order to coat the parylene, for example, parylene is firstly heated by a vaporizer in a vaporizer to be vaporized into a dimer state, and then pyrolyzed into a monomer state by secondary heating to cool the parylene The parylene may be converted to a polymeric state in the monomeric state and coated on at least one side of the second acoustic output 200. Meanwhile, a waterproof layer such as parylene may be coated on at least a part of the first sound output section 100 and the housing 200, as well as at least a part of the second sound output section 200.

3. housing

The housing 300 may be provided in a substantially cylindrical shape and may have a shape in which at least a part of the side surface is removed. That is, the housing 300 may be provided in a substantially circular cylindrical shape opened in at least a direction, and may be provided in a shape in which at least a part of the side surface is removed. For example, the housing 300 may be provided in a vertically penetrating manner, or may be provided in a shape in which a predetermined area is closed and upper and lower portions thereof are opened. The housing 300 includes a first member 310 having a substantially ring shape of a predetermined thickness and at least one second member 320 provided upward and downward from a predetermined region of the first member 310, . ≪ / RTI > That is, the second member 320 may be provided to surround the ring-shaped first member 310. Of course, if the first member 310 is provided in the form of a circular plate, the housing 300 having the upper and lower openings from the first member 310 can be realized. The second member 320 may be spaced apart from the first member 310 by a predetermined distance. For example, four second members 320 having a predetermined width may be provided at predetermined intervals. At this time, the gap between the second members 320 may be smaller than or equal to the width of the second member 320. [ For example, the spacing between the second members 320 may be between 10% and 100% of the width of the second member 320. In this embodiment, the second members 320 have the same width and spacing. That is, a plurality of second members 320 having a predetermined width may be provided at intervals equal to the width of the second member 320. On the other hand, the protrusion 321 may be provided on the inner side of the second member 320. That is, the protrusion 321 may protrude inward from the inner wall of the second member 320. In addition, the first member 310 can be seated on the protrusion 321. The first member 310 and the second member 320 may be separately manufactured and then joined so that the first member 310 is seated on the protrusion 321 of the second member 320, The first member 310 and the second member 320 may be integrally manufactured. Of course, the protrusion 321 may not be provided and the outer side of the first member 310 may be joined to the inner side of the second member 320, or may be integrally manufactured. The housing 300 can be brought into contact with the upper surface of the first member 310 and the second acoustic output unit 200, that is, the vibration element 220 of the piezoelectric speaker, and the protrusion 321 of the second member 320, And a first sound output unit 100, that is, a dynamic speaker, may be in contact with the lower side. That is, the first sound output unit 100 and the second sound output unit 200 may be spaced apart from each other with the first member 310 and the protrusion 321 interposed therebetween. Of course, when the first member 310 is joined to the inner wall of the second member 320 without the protrusion 321 on the inner side of the second member 320, The vibration element 220 may be joined and the first sound output unit 100 may be bonded to the lower surface of the first member 310. [ That is, the first sound output unit 100 and the second sound output unit 200 may be spaced apart from each other by the thickness of the first member 310. [ In addition, the first sound output unit 100 and the second sound output unit 200 may be spaced apart from each other by a predetermined distance, and at least a part of the area between the second members 320 may function as the emission hole 330. That is, the emission hole 330 may be provided so that the first sound output unit 100 and the first member 310 are spaced apart from each other by a predetermined distance, and correspond to a space therebetween. The emission hole 330 may be formed to have a size ranging from 5% to 90% of the upper surface area of the first acoustic output section 100. That is, at least one or more emission holes 330 may be formed. The total area of the emission holes 330 may be equal to or larger than the upper area of the first acoustic output unit 100, that is, 5% to 90% . ≪ / RTI > Of course, the size of the emission hole 330 is preferably 10% to 60% of the upper area of the first acoustic output unit 100, and more preferably 15% to 30% . The sound from the first sound output unit 100 is emitted through the emission hole 330. [ Accordingly, the sound from the second sound output unit 200 is directly emitted to the outside, and the sound from the first sound output unit 100 is emitted through the emission hole 330 of the housing 300, It is possible to further improve the sound quality. On the other hand, the sound output device can be made of a speaker such as a car speaker, a home speaker, or an amplifier and an earphone. In the case where the sound output apparatus is made of an earphone such as a cannular earphone, the housing 300 can be manufactured to have a size that can be inserted into the ear. At this time, it can be inserted into the ear from the second sound output unit 200. Accordingly, after the sound from the second sound output unit 200 is output first, the sound from the first sound output unit 100 is output thereafter, so that the two sounds are mixed with each other in the ear. The present invention can be manufactured by inserting the first sound output unit 100 and the second sound output unit 200 so as to be spaced apart from each other inside the housing 300. The first sound output unit 100 and the second sound output unit 200, The acoustic output device may be manufactured by combining a part of the housing 300 and another part of the housing 300 into which the second acoustic output unit 200 is inserted. For example, the thickness of the first member 310 may be halved, and the first member 310 may be formed to have a first thickness 310 and a second member 320 to surround the first thickness 310, A first sound output section 100 is inserted into the housing and a second sound output section 100 is provided inside the second housing in which a part of the second member 320 is formed so as to surround the second thickness on the upper side of the first member 310, And then the first and second housings are coupled to each other to form an acoustic output device. On the other hand, the acoustic output apparatus of the present invention is capable of driving a low voltage of 0.1 V to 5.0 V, preferably 0.1 V to 2.0 V, and more preferably 0.1 V to 0.5 V, at a low voltage. In particular, when applied to an earphone, it is possible to drive a low voltage of 0.1V to 0.2V, preferably, a low voltage of 0.1V to 0.18V. That is, in the piezoelectric element 210 of the second sound output unit 200, a plurality of piezoelectric layers are laminated and internal electrodes are formed between the piezoelectric layers. Since the piezoelectric layers are formed to have a thickness of 5 to 20 탆, The sound output unit 200 can be driven at a low voltage. The second acoustic output unit 200 according to the present invention can operate at a low voltage of 0.1 V to 0.5 V without using a separate amplifier for a piezoelectric speaker, It can be driven with low voltage by combining with speaker. In addition, the sound output apparatus of the present invention can be driven simultaneously by applying the same signal to the first and second sound output units 100 and 200. That is, a signal supplied from a signal source is directly applied to the first acoustic output unit 100, passes through the high-band filter, and is applied to the second acoustic output unit 200 so that the first and second acoustic output units 100 and 200 The signals of the same level can be applied to the first and second sound output units 100 and 200 simultaneously.

FIG. 4 is an exploded perspective view of an audio output apparatus according to a second embodiment of the present invention, FIG. 5 is an assembled perspective view of an audio output apparatus according to the second and third embodiments of the present invention, 3 is an exploded perspective view of an audio output device according to a third embodiment of the present invention, and FIG. 7 is an assembled cross-sectional view of an audio output device according to a third embodiment of the present invention.

4 to 7, the acoustic output apparatus according to the second and third embodiments of the present invention includes a first acoustic output unit 100 including a voice coil 140 and a diaphragm 150, A second sound output unit 200 provided on the sound output unit 100 and including the piezoelectric element 210 and the vibration element 220 and a second sound output unit 200 including the first and second sound output units 100 and 200 And may include a housing 300. In the second and third embodiments of the present invention, a piezoelectric element 210 is provided below the vibration element 220, and a second acoustic output unit 200, that is, a piezoelectric speaker can be implemented. Further, a discharge hole 330 is formed in a predetermined region of the second member 320 of the housing 300. 4, the first member 310 may be formed in a ring shape, and the first member 310a may be formed in a plate shape, as shown in FIG. 6 and FIG. In addition, the plate-like first member 310a may have a height difference in a predetermined area. For example, a step may be formed along the upper edge of the first member 310a to form a height difference. That is, the first member 310a may be provided in a plate shape so as to have a first region having a high height at a predetermined width of the edge and a second region having a lower height than the inner side of the edge. Here, the first region may be formed along the edge, for example, in a ring shape, or may be formed by at least two or more spaces. In addition, the second region of the first member 310a may be provided larger than the piezoelectric element 210. [ That is, the piezoelectric element 210 may be smaller than the vibration element 220 and smaller than the second area so that the piezoelectric element 210 does not contact the first area. The vibration element 220 of the second sound output unit 200 is brought into contact with the step of the plate-like first member 310a, that is, the first area, and the second area of the first member 310a, A resonance space may be provided between the first electrode 220 and the second electrode 210 to arrange the piezoelectric element 210. In addition, since the first member 310a is provided in a plate shape, the first member 310a separates the first and second sound output portions 100 and 200 from each other. That is, the plate-shaped first member 310a can be used as a separating member between the first and second sound output sections 100 and 200. [ The first and second sound output units 100 and 200 are separated by the separating member, that is, the plate-shaped first member 310a, so that sound output from the first and second sound output units 100 and 200 is separated from the housing 100, (300) without being mixed with each other. At least one second member 320 having a discharge hole 330 formed in a predetermined region so as to surround the ring-shaped first member 310 or the plate-shaped first member 310a may be provided. For example, one second member 320 is provided and a predetermined region of the second member 320 is cut in the vertical direction. The incision area may be provided with a signal line for supplying a signal to the second sound output unit 200. [ At this time, the width of the cut region of the second member 320, that is, the distance between the ends of the second member 320 may be set to 1% to 5% of the width of the second member 320. At least one emission hole 330 is formed on the second member 320. The emission holes 330 may be formed at a predetermined height below the first members 310 and 310a, for example, four spaced apart from each other by a predetermined distance, and may be formed at a height of a second region of the first acoustic output unit 100 have. That is, the second area of the first sound output unit 100 can be exposed at least partially by the emission hole 330. Further, the width of the discharge hole 330 may be formed to 20% to 80% of the width of the second member 320, for example, and may be formed to have a width of preferably 50%. The area of the emission hole 330 may be 5 to 90% of the area of the first acoustic output unit 100, that is, the area of the diaphragm 150. Of course, the size of the emission hole 330 is preferably 10% to 60% of the upper area of the first acoustic output unit 100, and more preferably 15% to 30% . If the first member 310 is provided in the form of a circular plate, the first and second sound output units 100 and 200 can be separated from each other, and the first and second sound output units 100 and 200 Can be prevented from being mixed in the housing 300. In addition,

As described above, in the acoustic output apparatus according to the embodiments of the present invention, the first acoustic output unit 100 and the second acoustic output unit 200 can be provided in the housing 300, and both the low- and high- Can be improved. That is, by providing the first acoustic output unit 100 having excellent bass characteristics, that is, the dynamic speaker and the second acoustic output unit 200 having excellent high-tone characteristics, i.e., the piezoelectric speaker in the housing 300, Can be improved. A predetermined space is provided between the first and second sound output units 100 and 200 in the housing 300 and a discharge hole 330 is formed in at least one area of the housing 300, The sound output from the sound output unit 100 to the spaced space can be emitted to the outside. That is, after the sound is output from the second sound output unit 200, sound is output from the first sound output unit 100 through the emission hole 330, so that the two sounds are mixed outside the housing 300. By mixing the two sounds outside the housing 300, sound quality can be improved as compared with the case where sound is mixed in the housing 300.

8 is a characteristic graph of a dynamic speaker, a piezoelectric speaker, and an acoustic output device according to the present invention. Here, A is a characteristic graph of a dynamic speaker, B is a characteristic graph of a piezoelectric speaker, and C is a characteristic graph of an acoustic output device according to an embodiment of the present invention in which a dynamic speaker and a piezoelectric speaker are combined in a housing. As shown in Fig. 6, the dynamic speaker A has a characteristic up to a frequency range of about 7 kHz, that is, a bass characteristic. However, at a frequency range exceeding 7 kHz, An attenuation phenomenon occurs. Therefore, it can be seen that the dynamic speaker has poor high-tone characteristics. In addition, the piezoelectric speaker (B) has a very good mid-range characteristic of 8 kHz or more, but in particular, a decay phenomenon of 30 dB or more occurs in a range of 3 kHz or less. However, it can be seen that the acoustic output apparatus C according to the embodiment of the present invention is excellent in the overall acoustic characteristics at the audible frequency up to 20 kHz. That is, It can be seen that the characteristic is almost the same as that of the dynamic speaker A, and the acoustic characteristic further higher than that of the piezoelectric speaker C is.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention.

100: First sound output unit 200: Second sound output unit
300: housing

Claims (10)

A housing having a housing space therein;
A first sound output section at least partially provided in the housing; And
And a second sound output unit spaced apart from the first sound output unit by a predetermined distance,
Wherein one of the first and second sound output sections includes a piezoelectric element and a vibration element,
Wherein the piezoelectric element includes a plurality of piezoelectric layers, the piezoelectric layer has a thickness of 5 to 20 占 퐉,
Wherein the plurality of piezoelectric layers comprise a non-polarized piezoelectric layer and a plurality of polarized piezoelectric layers provided at upper and lower portions of the non-polarized piezoelectric layer,
Wherein the vibration element is formed of a polymer-based or pulp-based material.
The acoustic output apparatus according to claim 1, wherein the vibration element has a Young's modulus of 1 MP to 10 GPa.
The sound output apparatus according to claim 1, comprising at least one emission hole formed in a predetermined region of the housing.
The sound output apparatus according to claim 3, wherein a spacing space is provided between the first and second sound output sections, and at least a part of the emission hole corresponds to the spacing space.
5. The sound output apparatus according to claim 4, wherein the housing includes a first member and at least one second member provided to surround the first member, and the emission hole is formed in a predetermined region of the second member.
The sound output apparatus according to claim 5, wherein the first member is provided in a plate shape having a predetermined thickness to separate the first and second sound output sections.
The sound output apparatus according to claim 6, wherein the discharge hole is formed to correspond to a space between the first member and the first sound output section.
The sound output apparatus according to claim 3, wherein the first and second sound output sections are simultaneously driven by signals of the same level. 9. The sound output apparatus of claim 8, wherein the first and second sound output sections are driven with a voltage of 0.1 to 5.0V.
The acoustic output apparatus according to claim 1, further comprising an opening formed in the vibration element.

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