TWI391913B - Acoustic device - Google Patents

Description

Sound device

The invention relates to a sound emitting device, in particular to a sound emitting device based on a carbon nanotube.

The sounding device generally consists of a signal input device and a sounding component, and the signal input device inputs a signal to the sounding component to emit a sound. The thermoacoustic device is one of the sounding devices, which is a sounding device based on the thermoacoustic effect, HDArnold and IBCrandall in the literature "The thermophone as a precision source of sound", Phys. Rev. 10, p22-38 ( A simple thermoacoustic device is described in 1917) which uses a platinum sheet as the sounding element. Since the sounding frequency of the sounding element is closely related to the heat capacity per unit area, that is, the heat capacity per unit area is large, the sounding frequency range is narrow, and the sound wave intensity is low; the heat capacity per unit area is small, the sounding frequency range is wide, and the sound wave intensity is high. Therefore, in order to obtain a wide range of sounding frequencies and a high sound wave intensity, it is required that the heat capacity per unit area of the sounding element is as small as possible. The metal platinum sheet with smaller heat capacity is limited by the material itself, and the thickness can be as small as 0.7 micron, and the sounding device using the platinum sheet as the sounding element can generate a sound frequency of up to only 4,000. hertz.

In addition, Fan Shoushan et al. disclose a sounding device using a carbon nanotube, see the literature "Flexible, Stretchable, Transparent Carbon Nanotube Thin Film Loudspeakers", Fan Shoushan et al., Nano Letters, Vol. 8 (12), p4539- 4545 (2008). Please refer to Figure 1, the hair The acoustic device 100 includes a substrate 108, a carbon nanotube film 104, and two electrodes 106. The carbon nanotube film 104 is disposed on the substrate 108. The two electrodes 106 are electrically connected to the carbon nanotube film 104, respectively, and the carbon nanotube film 104 is thermally induced by current supply. Since the sound generating device 100 uses the carbon nanotube film 104 as a sounding element, the carbon nanotube film 104 has a large specific surface area and a small heat capacity per unit area and an extremely thin thickness, so that the sound generating device 100 can emit a human ear. The sound wave intensity that can be heard and has a wide range of vocal frequencies (100 Hz to 100 kHz).

However, since the carbon nanotube film 104 is directly in contact with the two electrodes 106 by its own viscosity, the binding force of the carbon nanotube film 104 to the two electrodes 106 is small. The fixing with the two electrodes 106 is not strong enough, so the electrical connection between the carbon nanotube film 102 and the two electrodes 106 may be reduced, thereby further affecting the sounding effect and stability of the entire sounding device 100. .

In view of the above, it is necessary to provide a sounding device that effectively improves the electrical connection between the sound emitting element and the electrode.

A sounding device comprising: a first electrode, a second electrode, and a first carbon nanotube structure. The first electrode comprises a conductor and a conductive bonding layer, and the second electrode comprises an electrical conductor and a conductive bonding layer. The carbon nanotube structure is electrically connected between the first electrode and the conductive bonding layer of the second electrode. The conductive bonding layer is formed on the electrical conductors of the first electrode and the second electrode, and the carbon nanotube structure is fixed to the conductive bonding layer, and the conductive bonding layer penetrates into the carbon nanotube structure.

A sounding device comprising: a substrate, a sound emitting element, a first electrode and a second electrode disposed at intervals of the substrate by a conductive paste. The sound emitting element includes a carbon nanotube structure fixed to and electrically connected to the first electrode and the second electrode. The conductive paste penetrates into the carbon nanotube structure.

Compared with the prior art, the sounding device has the following advantages: since the conductive paste or the conductive adhesive layer included in the first electrode and the second electrode penetrates into the carbon nanotube structure, the The carbon nanotube structure is well fixed to the first electrode and the second electrode, and further increases the contact area between the sound emitting element and the first electrode and the second electrode, so that the sound emitting element and the first electrode The second electrode has good electrical connectivity, so that the sounding effect and stability of the sounding device are better.

Hereinafter, a sound emitting device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 2 and FIG. 3 , the first embodiment of the present invention provides a sounding device 10 . The sounding device 10 includes a frame 18 , a first electrode 14 a , a second electrode 14 b , and a sound emitting element 12 .

The frame 18 is used to support the first electrode 14a and the second electrode 14b. In this embodiment, the frame 18 has a frame structure, and the first electrode 14a is suspended from the second electrode 14b. In the framework structure. The frame 18 is made of an insulating material, which is glass, ceramic, resin, wood material, quartz or plastic. In this embodiment, the material of the frame 18 is a resin.

The first electrode 14a and the second electrode 14b are arranged in parallel at the frame Body 18. The first electrode 14a and the second electrode 14b can fix the both ends of the first electrode 14a and the second electrode 14b to the frame body 18 by bolting or bonding of a bonding agent. The sound emitting element 12 is placed on the first electrode 14a and the second electrode 14b, and is electrically connected to the first electrode 14a and the second electrode 14b. The first electrode 14a and the second electrode 14b also have a function of supporting the sound emitting element 12.

The first electrode 14a and the second electrode 14b have the same structure. The first electrode 14a and the second electrode 14b include a conductor 142 and a conductive bonding layer 146 disposed on the conductor 142. The material of the conductor 142 is a metal or an alloy such as one or more of stainless steel, copper, iron, cobalt, nickel, platinum or palladium, or an alloy of the above metals. The shape of the conductor 142 may be selected from one of a rod shape, a strip shape, a block shape, or the like. In this embodiment, the material of the conductor 142 is preferably stainless steel and has a long rod shape.

The material of the conductive adhesive layer 146 is a conductive paste or a conductive paste. The main components of the conductive paste or the conductive paste include metal particles, a binder, a solvent, etc., and the metal particles may be gold particles, silver particles or Aluminum particles, etc. This embodiment is preferably a silver conductive paste, that is, the metal particles in the conductive paste are silver particles.

The sounding element 12 includes a carbon nanotube structure. The carbon nanotube structure comprises at least one carbon nanotube membrane, at least one nanocarbon line-like structure, or a combination thereof. The thickness of the carbon nanotube structure (the diameter in the case of a linear structure) is 0.5 nm to 1 mm. Preferably, the carbon nanotube structure has a thickness of 0.5 microns. The carbon nanotube structure may have a heat capacity per unit area of less than 2 x 10-4 joules per square centimeter Kelvin. Preferably, the carbon nanotube structure has a heat capacity per unit area of less than 1.7 x 10 ^-6 joules per square centimeter Kelvin.

The carbon nanotubes in the carbon nanotube structure include one or more of a single-walled carbon nanotube, a double-walled carbon nanotube, and a multi-walled carbon nanotube. The single-walled carbon nanotube has a diameter of 0.5 nm to 50 nm, the double-walled carbon nanotube has a diameter of 1.0 nm to 50 nm, and the multi-walled carbon nanotube has a diameter of 1.5. Nano ~ 50 nm. In this embodiment, the carbon nanotube structure as the sounding element 12 includes a carbon nanotube film. A plurality of carbon nanotubes are arranged in a preferred orientation in the same direction in the carbon nanotube structure, and a plurality of carbon nanotubes in the carbon nanotube structure are arranged in a direction perpendicular to the first electrode and the second electrode .

Specifically, in this embodiment, two conductive bodies 142 may be disposed in parallel to the frame 18, and a surface of each of the conductive bodies 142 is provided with a conductive bonding layer 146. In order to fix the sound emitting element 12 in the conductive bonding layer 146, a liquid conductive paste may be applied to each of the conductors 142, and when the coated conductive paste is in a liquid state, the sounding element 12 is flattened. Spread on the conductive paste. Since the sounding element 12 is a carbon nanotube structure, there is a gap between the carbon nanotubes of the carbon nanotube structure, so that the conductive paste will be immersed in the void of the carbon nanotube structure, thereby A liquid conductive paste is immersed in the carbon nanotube structure. The conductive paste is cured to form the conductive bonding layer 146, the carbon nanotube structure is fixed to the conductive bonding layer 146, and the conductive bonding layer 146 is infiltrated into the carbon nanotube structure. Therefore, the sound emitting element 12 is fixed to the first electrode 14a and the second electrode 14b, and is electrically connected to the first electrode 14a and the second electrode 14b, thereby effectively improving the stability of the sounding device 10.

Since the sound generating element 12 including the carbon nanotube structure is composed of a uniformly distributed carbon nanotube, since the carbon nanotube itself has a large specific surface area, the carbon nanotube structure also has a large Specific surface area, smaller heat capacity per unit area and larger heat dissipation surface. After inputting the audio signal, the sounding element 12 can rapidly rise and fall, generate periodic temperature changes, and quickly exchange heat with the surrounding medium, so that the density of the surrounding medium can be periodically changed to emit sound.

The working medium of the sound emitting element 12 is not limited, and only needs to satisfy a resistivity higher than that of the sound emitting element 12. The medium includes a gaseous medium or a liquid medium. The gaseous medium includes air. The liquid medium includes one or more of a non-electrolyte solution, water, an organic solvent, and the like.

The sound pressure device 10 provided by the embodiment of the present invention has a sound pressure level of more than 50 decibels per watt, and the sounding frequency ranges from 1 Hz to 100,000 Hz (ie, 1 Hz to 100 kHz). The sounding device may have a distortion of less than 3% in the frequency range of 500 Hz to 40,000 Hz.

Referring to FIG. 4 and FIG. 5 , a second embodiment of the present invention provides a sounding device 20 . The sounding device 20 includes a frame 28 , a plurality of first electrodes 24 a , a plurality of second electrodes 24 b , and a sound emitting element 22 . In this embodiment, the frame 28, the first electrode 24a, the second electrode 24b, and the sound emitting element 22 are completely identical in structure to the frame 18, the first electrode 14a, the second electrode 14b, and the sounding element 22 in the first embodiment. the same. The difference is that the first embodiment includes a plurality of first electrodes 24a and a plurality of second electrodes 24b.

The plurality of first electrodes 24a and the plurality of second electrodes 24b are alternately spaced apart from the frame body 28, and the plurality of first electrodes 24a and the plurality of second portions The electrode 24b is supported by the frame 28. A second electrode 24b is disposed between each two adjacent first electrodes 24a, and a first electrode 24a is disposed between each two adjacent second electrodes 24b, and each two adjacent ones of the first electrodes The distance between 24a and one of the second electrodes 24b is equal. In this embodiment, the sounding device 20 includes four first electrodes 24a and four second electrodes 24b.

The structures of the first electrode 24a and the second electrode 24b are the same as those of the first electrodes 14a and 14b in the first embodiment. The first electrode 24a and the second electrode 24b include a conductor 242 and are disposed on the conductor 242. A conductive bonding layer 246 of the surface. The material of the conductor 242 is a metal or an alloy such as one or more of stainless steel, copper, iron, cobalt, nickel, platinum or palladium, or an alloy of the above metals. The shape of the electric conductor 242 may be selected from one of a rod shape, a strip shape, a block shape, or the like. In this embodiment, the material of the conductor 242 is preferably stainless steel and has a long rod shape. The material of the conductive adhesive layer 246 is a conductive paste or a conductive paste. The main components of the conductive paste or the conductive paste include metal particles, a binder, a solvent, etc., and the metal particles may be gold particles, silver particles or Aluminum particles, etc. This embodiment is preferably a silver conductive paste, and the metal particles in the conductive paste are silver particles.

In this embodiment, eight conductors 242 may be disposed in parallel to the frame 28, and a surface of each of the conductors 242 is provided with a conductive bonding layer 246. In order to fix the sound emitting element 22 in the conductive bonding layer 246, a liquid conductive paste may be applied to each of the conductors 242, and when the coated conductive paste is in a liquid state, the sounding element 22 is flattened. Spread on a liquid conductive paste. And since the sounding element 22 is a carbon nanotube structure, the nanocarbon There is a gap between the carbon nanotubes of the tube structure, so that the conductive paste will be immersed in the voids of the carbon nanotube structure, thereby immersing the liquid conductive paste into the carbon nanotube structure. After the conductive paste is cured to form the conductive bonding layer 246, the carbon nanotube structure can be fixed to the conductive bonding layer 246, and the conductive bonding layer 246 is infiltrated into the carbon nanotube structure. Therefore, the sound emitting element 22 is fixed to the first electrode 24a and the second electrode 24b, and is electrically connected to the first electrode 24a and the second electrode 24b, thereby effectively improving the stability of the sounding device 20.

The sounding element 22 is the same as the sounding element 12 of the first embodiment, the sounding element 22 is a carbon nanotube structure, and the carbon nanotube structure comprises at least one carbon nanotube film.

The sounding device 20 can be connected to the external signal by the plurality of first electrodes 24a and the plurality of second electrodes 24b. Specifically, the plurality of first electrodes 24a may be connected to a signal input device and then electrically connected to one end of a signal input device, and then the plurality of second electrodes 24b are connected by a conductive element and the signal The other end of the input device is electrically connected. The above connection method can realize the parallel connection of the sound emitting elements 22 between adjacent electrodes. The sounding elements 22 connected in parallel have a small electrical resistance, which can lower the operating voltage of the sounding device 20.

As shown in FIG. 6 and FIG. 7, a third embodiment of the present invention provides a sounding device 30. The sounding device 30 includes a substrate 38, a plurality of first electrodes 34a, a plurality of second electrodes 34b, and a sounding element 32.

The base body 38 mainly functions to carry the plurality of first electrodes 34a, the plurality of second electrodes 34b, and the sound emitting element 32. The base 38 The shape and size are not limited, and the material is an insulating material or a material having poor conductivity. In addition, the material of the base 38 should have better thermal insulation properties, so that the heat generated by the sound generating element 32 is prevented from being absorbed by the base 38, and the purpose of heating the surrounding medium and sounding is not achieved. The material of the base 38 may be glass, resin or ceramic. In this embodiment, the base 38 is a square glass plate.

The plurality of first electrodes 34a and the plurality of second electrodes 34b are alternately spaced apart from the base 38. A second electrode 34b is disposed between each two adjacent first electrodes 34a, and a first electrode 34a is disposed between each two adjacent second electrodes 34b, and each two adjacent ones are first The distance between the electrode 34a and one of the second electrodes 34b is equal.

The first electrode 34a and the second electrode 34b may be in the form of a layer (filament or strip), a rod, a strip, a block or other shapes, and the cross-sectional shape thereof is a circle, a square, a trapezoid, a triangle or irregular shape. In order to prevent the heat of the sound emitting element 32 from being excessively absorbed by the first electrode 34a and the second electrode 34b to affect the sounding effect, the contact area between the first electrode 34a and the second electrode 34b and the sound emitting element 32 is preferably small, so the first The shape of one electrode 34a and second electrode 34b is preferably a filament shape or a ribbon shape. The material of the first electrode 34a and the second electrode 34b may be selected from a metal, a conductive paste, a conductive paste or indium tin oxide (ITO), or the like. The height of the first electrode 34a and the second electrode 34b is not limited, and is preferably 10 micrometers to 1 centimeter. In this embodiment, the material of the first electrode 34a and the second electrode 34b is a conductive paste having an elongated strip shape and a height of 15 micrometers.

The sound emitting element 32 is the same as the sound emitting element 12 in the first embodiment, and is a carbon nanotube structure including at least one carbon nanotube membrane. The sounding element 32 is disposed on the plurality of first electrodes 34a and the plurality of second electrodes 34b. Further, the sound emitting element 32 is fixed to the plurality of first electrodes 34a and the plurality of second electrodes 34b.

It can be understood that the number of the first electrode 34a and the second electrode 34b in the third embodiment of the present invention is not limited. The sounding device 30 in this embodiment may also include only one first electrode 34a and one second electrode 34b.

In this embodiment, the conductive paste can be printed on the substrate 38 by screen printing to form four first electrodes 34a and four second electrodes 34b, the four first electrodes 34a and the four second electrodes. 34b are alternately spaced and arranged in parallel. The sound emitting element 32 is placed on the liquid conductive paste when the conductive paste is in a liquid state. Since the sounding element 32 is a carbon nanotube structure, a plurality of carbon nanotubes of the carbon nanotube structure have a gap therebetween. The liquid conductive paste is immersed in the gap of the carbon nanotube structure to immerse the conductive paste in the carbon nanotube structure. Then, the liquid conductive paste is cured. After the liquid conductive paste is solidified, four first electrodes 34a and four second electrodes 34b are formed, and the sound emitting element 32 is fixed to the four first electrodes 34a and four. The second electrode 34b. The first electrode 34a and the second electrode 34b also support the sounding element 32.

In this embodiment, the sounding device 30 further includes a first conductive element 346 and a second conductive element 348. The first conductive element 346 and the second conductive element 348 are electrically connected to the first electrode 32a and the second electrode 32b in the sounding device 30, respectively. The sounding device 30 is electrically connected to an external circuit by the first conductive member 346 and the second conductive member 348, thereby inputting an audio signal to the sound emitting member 32.

Compared with the prior art, the sounding device of the embodiment of the present invention has the following advantages: since the conductive paste or the conductive adhesive layer included in the first electrode and the second electrode penetrates into the carbon nanotube structure, The carbon nanotube structure can be well fixed to the first electrode and the second electrode, and the contact area between the sound emitting element and the first electrode and the second electrode is increased, so that the sounding element and the first The first electrode and the second electrode have good electrical connectivity, so that the sounding effect and stability of the sounding device are better.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by those skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

10,20,30‧‧‧ sounding device

12,22,32‧‧‧Acoustic components

18, 28‧‧‧ frame

14a, 24a, 34a‧‧‧ first electrode

14b, 24b, 34b‧‧‧ second electrode

38‧‧‧ base

142,242‧‧‧Electrical conductor

146,246‧‧‧ Conductive bonding layer

346‧‧‧First conductive element

348‧‧‧Second conductive element

Figure 1 is a cross-sectional view of a sound generating device in the prior art.

2 is a plan view of a sound emitting device according to a first embodiment of the present invention.

Figure 3 is a cross-sectional view taken along line III-III of Figure 2.

4 is a top plan view of a sound emitting device according to a second embodiment of the present invention.

Figure 5 is a cross-sectional view taken along line V-V of Figure 4 .

Figure 6 is a plan view of a sound emitting device according to a third embodiment of the present invention.

Figure 7 is a cross-sectional view taken along line VII-VII of Figure 6.

10‧‧‧ Sounding device

12‧‧‧ Sounding components

14a‧‧‧First electrode

14b‧‧‧second electrode

18‧‧‧ frame

142‧‧‧Electrical conductor

146‧‧‧ Conductive bonding layer

Claims (18)

A sounding device comprising: a first electrode, the first electrode comprising a conductor and a conductive bonding layer; a second electrode comprising a conductor and a conductive bonding layer; and a nano carbon a tube structure, the carbon nanotube structure is electrically connected between the first electrode and the conductive bonding layer of the second electrode; and the improvement is that the conductive bonding layer is formed on the first electrode and the second electrode The carbon nanotube structure is embedded and fixed to the conductive bonding layer, and the conductive bonding layer penetrates into the carbon nanotube structure. The sounding device of claim 1, wherein the sounding device further comprises a frame, and the first electrode and the second electrode are fixed to the frame. The sounding device of claim 1, wherein the sounding device comprises a plurality of first electrodes and a plurality of second electrodes, and the plurality of first electrodes and the plurality of second electrodes are alternately arranged, and The carbon nanotube structure is electrically connected. The sounding device of claim 3, wherein the distance between the adjacent one of the first electrodes and the second electrode is equal. The sounding device according to claim 1, wherein the electrical conductor is in the form of a strip or a rod. The sounding device according to claim 1, wherein the material of the electrical conductor is a metal or an alloy. The sounding device of claim 6, wherein the metal is copper, iron, cobalt, nickel, platinum or palladium. The sounding device according to claim 1, wherein the conductor is made of stainless steel. The sounding device of claim 1, wherein the material of the conductive adhesive layer is a conductive paste. The sounding device of claim 1, wherein the first electrode is disposed in parallel with the second electrode. The sounding device according to claim 1, wherein the carbon nanotube structure comprises at least one carbon nanotube film, a plurality of nano carbon pipes or a carbon nanotube film and a nano carbon pipe. Composite structure. A sounding device comprising: a substrate; a first electrode and a second electrode, wherein the first electrode and the second electrode are formed on the substrate by a conductive paste; a sounding element, the sounding element comprises a The carbon nanotube structure is embedded and fixed to and electrically connected to the first electrode and the second electrode; and the improvement is that the conductive paste penetrates into the carbon nanotube structure. The sounding device of claim 12, wherein the sounding device comprises a plurality of first electrodes and a plurality of second electrodes, and the plurality of first electrodes and the plurality of second electrodes are alternately spaced apart. The sounding device of claim 13, wherein the distance between each two adjacent one of the first electrodes and the second electrode is equal. The sounding device according to claim 12, wherein the first electrode and the second electrode are in the form of a filament, a strip, a rod, a strip or a block. The sounding device of claim 12, wherein the carbon nanotube structure comprises at least one carbon nanotube film, a plurality of nano carbon pipes or one The composite structure of the carbon nanotube membrane and the nano carbon pipeline. The sounding device according to claim 12, wherein the material of the substrate is glass, resin or ceramic. The sounding device of claim 12, wherein the first electrode is disposed in parallel with the second electrode.