CN101820571B - Speaker system - Google Patents

Abstract

The present invention relates to a loudspeaker system, which includes: a loudspeaker; and a power amplifier, the power amplifier amplifies the power of the received audio electric signal into an amplified voltage signal, and drives the loudspeaker to sound; wherein: the loudspeaker includes a thermophonic The element and at least two electrodes are arranged at intervals and electrically connected with the thermoacoustic element, and the at least two electrodes input the amplified voltage signal into the thermoacoustic element. The loudspeaker system is applied in the field of electroacoustic conversion, has a simple structure, can work under the condition of no magnetism, and has a wide range of sounding frequency and high sounding intensity.

Description

speaker system

technical field

The invention relates to a loudspeaker system, in particular to a loudspeaker system based on thermal sound generation. the

Background technique

A loudspeaker system in the prior art includes a loudspeaker and a power amplifier, the power amplifier is used to receive an electrical audio signal and amplify the power of the electrical audio signal to drive the loudspeaker to produce sound. There are many types of existing loudspeakers, which can be divided into electrodynamic loudspeakers, electrostatic loudspeakers and piezoelectric loudspeakers according to their working principles. Although they work in different ways, they generally push the surrounding air by generating mechanical vibrations, causing the air medium to fluctuate so as to realize the conversion of "electricity-force-acoustic". Among them, the dynamic speaker is the most widely used. the

In the existing electrodynamic loudspeaker, a voice coil is placed in a changing magnetic field, and vibrates with the change of the magnetic field, and the vibration of the voice coil drives the vibrating diaphragm connected with it to produce sound. However, the dynamic loudspeaker must work under the condition of magnetism. Furthermore, no matter the dynamic loudspeaker, electrostatic loudspeaker or piezoelectric loudspeaker in the prior art, its structure is relatively complicated, and it is difficult to make it thinner and smaller. the

Since the early 1990s, nanomaterials represented by carbon nanotubes (see Helical microtubules of graphitic carbon, Nature, Sumio Iijima, vol 354, p56 (1991)) have attracted great attention for their unique structures and properties. s concern. However, a single carbon nanotube is nanoscale, and a large number of carbon nanotubes are easy to aggregate and difficult to disperse to form a uniform carbon nanotube film, which limits the application of carbon nanotubes in the macroscopic field. The Chinese patent No. 02134760.3 filed by Jiang Kaili and others on September 16, 2002 and announced on August 20, 2008 discloses a carbon nanotube rope. carbon nanotube bundle segments, and the carbon nanotubes in the carbon nanotube rope are basically arranged along the same direction. The carbon nanotube rope can conveniently use the carbon nanotube in the macro field. the

In recent years, with the continuous deepening of research on carbon nanotubes and nanomaterials, their broad application prospects continue to emerge. For example, due to the unique electromagnetic, optical, mechanical, and chemical properties of carbon nanotubes, a large number of researches on their application in fields such as field emission electron sources, sensors, new optical materials, and soft ferromagnetic materials have been continuously reported. However, carbon nanotubes have not been found to be used in the acoustic field in the prior art. the

Contents of the invention

In view of this, it is necessary to provide a loudspeaker system, which has a simple structure, can work under non-magnetic conditions, and has a wide range of sounding frequency and high sounding intensity. the

A loudspeaker system, which includes: a loudspeaker; and a power amplifier, the power amplifier amplifies the power of the received audio electric signal into an amplified voltage signal, and drives the loudspeaker to sound; wherein: the loudspeaker includes a thermal sound-generating element and at least Two electrodes are arranged at intervals and electrically connected with the thermoacoustic element, and the at least two electrodes input the amplified voltage signal into the thermoacoustic element. The loudspeaker system is applied in the field of electroacoustic conversion, has a simple structure, can work under the condition of no magnetism, and has a wide range of sounding frequency and high sounding intensity. the

Compared with the prior art, the loudspeaker system has the following advantages: first, the loudspeaker system uses the thermoacoustic element as an energy conversion device to convert electric energy into sound energy through thermal energy, without requiring other complicated structures such as magnets, so The structure of the loudspeaker system is relatively simple, which is beneficial to reduce the cost of the loudspeaker system and can be applied in a wider field. Second, the loudspeaker system uses an externally input audio signal to cause the temperature of the thermoacoustic element to change, so that the surrounding medium expands and contracts rapidly, and then emits sound waves without a diaphragm, so the loudspeaker system can be used under non-magnetic conditions. down to work. the

Description of drawings

Fig. 1 is a schematic diagram of the connection relationship of the speaker system according to the embodiment of the present invention. the

Fig. 2 is a schematic diagram of the working circuit of the loudspeaker system according to the embodiment of the present invention. the

FIG. 3 is a schematic diagram of a voltage biasing manner of a speaker system according to an embodiment of the present invention. the

Fig. 4 is a schematic structural diagram of a carbon nanotube segment of a carbon nanotube structure in a loudspeaker system according to an embodiment of the present invention. the

Fig. 5 is a scanning electron micrograph of the carbon nanotube film in the speaker system of the embodiment of the present invention. the

Fig. 6 is a scanning electron micrograph of carbon nanotube wires in the speaker system of the embodiment of the present invention. the

Fig. 7 is a scanning electron micrograph of carbon nanotube strands in the speaker system of the embodiment of the present invention. the

Fig. 8 is a frequency response characteristic curve of the speaker in the speaker system of the embodiment of the present invention. the

Detailed ways

The loudspeaker system of the embodiment of the present invention will be described in detail below with reference to the accompanying drawings. the

Referring to FIG. 1 , an embodiment of the present invention provides a speaker system 10 , which includes a speaker 12 , a power amplifier 14 and an audio signal source 20 . The power amplifier 14 is electrically connected to the speaker 12 . The audio signal source 20 is electrically connected to the power amplifier 14 . the

The audio signal source 20 provides an audio electrical signal. In this embodiment, the electrical audio signal is an analog signal. The frequency of change of the audio electric signal changes according to the change of sound frequency. The audio signal source 20 can be a radio, a tape recorder, a player or a computer. the

The power amplifier 14 is electrically connected to the audio signal source 20 . Specifically, the audio signal source 20 has an audio electrical signal output terminal. The power amplifier 14 is electrically connected to the audio signal output end. The power amplifier 14 amplifies the power of the audio electrical signal and outputs an amplified voltage signal. Specifically, the power amplifier 14 has two output terminals 114 and an input terminal 112, the input terminal 112 is electrically connected to an audio signal source 20, the output terminal 114 is electrically connected to the speaker 12, and is input according to the input terminal 112. The audio electrical signal transmits an amplified voltage signal to the speaker 12 . the

In order to enable the speaker 12 to emit normal frequency sound, the power amplifier 14 can output an amplified voltage signal with a bias voltage. Please refer to FIG. 2 , in this embodiment, the power amplifier 14 is a class A power amplifier, which includes at least a first resistor R1 , a second resistor R2 , a third resistor R3 , a capacitor and a transistor. The triode has a base B, an emitter E and a collector C. One end of the capacitor is electrically connected to the output end of the audio signal source 20 , and the other end is electrically connected to the base B of the triode. A DC voltage source Vcc is connected in series with the first resistor R1 to the base B of the triode. The base B of the triode is connected in series with the second resistor R2 and grounded. The emitter E is connected to an output terminal 114 of the power amplifier 14 , and the DC voltage source Vcc is connected to the other output terminal 114 of the power amplifier. The collector C is connected in series with the third resistor R3 and grounded. the

It can be understood that the power amplifier 14 is not limited to the above-mentioned Class A power amplifier, as long as a biased amplified voltage signal can be transmitted to the thermoacoustic element 12 according to the audio signal source 20, so that the voltage of the amplified voltage signal is all positive Or power amplifiers 14 with negative values, such as Class D power amplifiers, are all within the protection scope of the present invention. Please refer to Figure 3, the biased voltage signals are all positive voltages. the

The speaker 12 includes a thermoacoustic element 122 and at least two electrodes 124 . The at least two electrodes 124 are spaced apart and electrically connected to the thermoacoustic element 122 . The two output terminals 114 of the power amplifier 14 are respectively connected to the two electrodes 124 of the thermoacoustic element 122 . In this embodiment, the emitter E of the power amplifier 14 is directly electrically connected to one electrode 124 of the speaker 12, and the DC voltage source Vcc is directly electrically connected to the other electrode 124 of the speaker 12, so that the DC voltage source Vcc is electrically connected to the other electrode 124 of the speaker 12. The speaker 12 is connected in series to the emitter E of the power amplifier 14 . the

It can be understood that when the speaker 12 includes a plurality of electrodes 124, any two adjacent electrodes 124 are respectively electrically connected to the two output terminals 114 of the power amplifier 14, so that the power amplifier 14 provides An amplified voltage signal is input into the thermoacoustic element 122 between the electrodes 124 , so that the sound emitting element 122 between two adjacent electrodes 124 is connected in parallel through the two electrodes 124 . the

In this embodiment, the thermoacoustic element 122 is a carbon nanotube structure. The carbon nanotube structure includes a plurality of carbon nanotubes, and the plurality of carbon nanotubes are in contact with each other to form a uniform conductive network. Preferably, the carbon nanotube structure includes ordered carbon nanotubes, and the carbon nanotubes are preferentially oriented along a fixed direction. the

The carbon nanotube structure is a self-supporting structure. The so-called "self-supporting structure" means that the carbon nanotube structure can maintain its own specific shape without being supported by a support. In the carbon nanotube structure of the self-supporting structure, multiple carbon nanotubes attract each other through van der Waals force, so that the carbon nanotube structure has a specific shape. Therefore, the two ends of the carbon nanotube structure can be supported by the support body, and the other parts of the carbon nanotube structure are suspended, so as to fully contact with the surrounding gas or liquid medium. In addition, the carbon nanotube structure can also be directly disposed on the surface of a substrate. the

The carbon nanotube structure has a large specific surface area, and thus has a large surface area in contact with external gas or liquid medium. Preferably, the carbon nanotube structure is layered, linear or other shapes, and has a relatively large specific surface area. the

When the carbon nanotube structure is a layered structure, the thickness is preferably 0.5 nanometers to 1 millimeter. If the thickness of the carbon nanotube structure is too large, the specific surface area will decrease and the heat capacity will increase; if the thickness of the carbon nanotube structure is too small, the mechanical strength will be poor and the durability will not be good enough. When the thickness of the carbon nanotube structure is relatively small, such as less than 10 microns, the carbon nanotube structure has good light transmittance. The carbon nanotubes in the carbon nanotube structure include one or more of single-wall carbon nanotubes, double-wall carbon nanotubes and multi-wall carbon nanotubes. The single-walled carbon nanotubes have a diameter of 0.5 nm to 50 nm, the double-walled carbon nanotubes have a diameter of 1.0 nm to 50 nm, and the multi-walled carbon nanotubes have a diameter of 1.5 nm to 50 nm. the

It can be understood that the specific structure of the carbon nanotube structure is not limited. Preferably, the carbon nanotube structure satisfies the following conditions: it has a relatively large specific surface area and a small heat capacity per unit area (less than 2×10 ^{- 4} joules per square centimeter Kelvin, preferably less than 1 x 10 ^-6 joules per square centimeter Kelvin).

The carbon nanotube structure includes at least one carbon nanotube film, at least one carbon nanotube linear structure or a composite structure composed of the carbon nanotube film and the carbon nanotube linear structure. the

The carbon nanotubes in the carbon nanotube film are uniformly distributed and closely combined by van der Waals force. The carbon nanotubes in the carbon nanotube film are arranged in disorder or order. The disorder here means that the arrangement direction of carbon nanotubes is irregular; the order means that the arrangement direction of at least most carbon nanotubes has certain rules, such as the preferred orientation along one fixed direction or the preferred orientation along several fixed directions. Specifically, when the carbon nanotube film includes carbon nanotubes arranged in disorder, the carbon nanotubes are intertwined or arranged isotropically; Or multiple directions are preferentially aligned. the

Preferably, the carbon nanotube film is an ordered carbon nanotube film obtained by directly pulling from a super-aligned carbon nanotube array. The thickness of the carbon nanotube film is 0.5 nanometers to 100 microns, the length of the carbon nanotube film is not limited, and the width is the width of the carbon nanotube array. Please refer to FIG. 4 and FIG. 5 , further, the carbon nanotube film in the carbon nanotube structure includes a plurality of carbon nanotubes connected end to end along the pulling direction, arranged in a preferred orientation and evenly distributed. Specifically, the carbon nanotube film includes a plurality of carbon nanotube segments 143 connected end to end and arranged in an orientation, each carbon nanotube segment 143 has approximately the same length, and the two ends of the carbon nanotube segments 143 are connected to each other by van der Waals force . The carbon nanotube segment 143 includes a plurality of carbon nanotubes 145 that are substantially equal in length and arranged parallel to each other. When the carbon nanotube structure includes multiple layers of carbon nanotube films stacked on each other, there is a cross angle α between the carbon nanotubes in two adjacent layers of carbon nanotube films, and α is greater than or equal to 0 degrees and less than or equal to 90 degrees . The light transmittance of the single-layer carbon nanotube film is 67%-95%. For the structure and preparation method of the carbon nanotube film, please refer to Chinese Patent Application No. 200710073265.4 filed by Fan Shoushan et al. on February 9, 2007 and published on August 13, 2008. To save space, it is only cited here, but all the technical disclosures of the above applications should also be regarded as a part of the technical disclosures of the present application. the

The carbon nanotube wire structure includes at least one carbon nanotube wire, a bundle structure formed by a plurality of carbon nanotube wires arranged in parallel with each other, or a stranded wire structure formed by a plurality of carbon nanotube wires arranged in a twisted manner with each other. The carbon nanotube wire is a twisted carbon nanotube wire or a non-twisted carbon nanotube wire. The carbon nanotube structure may include a carbon nanotube linear structure or a layered structure formed by a plurality of carbon nanotube linear structures arranged side by side, intersecting or interweaving, so that the carbon nanotube structure has a larger specific surface area. the

Please refer to FIG. 6 , the non-twisted carbon nanotube wire is obtained by treating the above-mentioned carbon nanotube film obtained from the super-aligned carbon nanotube array through organic solvent treatment. Specifically, the entire surface of the carbon nanotube film is infiltrated with an organic solvent, and under the action of the surface tension generated when the volatile organic solvent volatilizes, multiple carbon nanotubes in the carbon nanotube film that are parallel to each other are tightly bound together by van der Waals force. Combined, so that the carbon nanotube film shrinks into a non-twisted carbon nanotube wire. The organic solvent is a volatile organic solvent, such as ethanol, methanol, acetone, dichloroethane or chloroform. Compared with the carbon nanotube film without organic solvent treatment, the non-twisted carbon nanotube wire treated by organic solvent has a smaller specific surface area and lower viscosity. The non-twisted carbon nanotube wire includes a plurality of carbon nanotubes arranged along the length direction of the carbon nanotube wire and connected end to end. Specifically, the non-twisted carbon nanotube wire includes a plurality of carbon nanotube segments connected end-to-end by van der Waals force, and each carbon nanotube segment includes a plurality of carbon nanotube segments that are parallel to each other and closely combined by van der Waals force. nanotube. The carbon nanotube segment has any length, thickness, uniformity and shape. The length of the carbon nanotube wire is not limited, and the diameter is 0.5 nanometers to 100 microns. For the carbon nanotube wire and its preparation method, please refer to Chinese Patent Application No. 200510120716.6 filed by Fan Shoushan et al. on December 16, 2005 and published on June 20, 2007. To save space, it is only cited here, but all the technical disclosures of the above applications should also be regarded as a part of the technical disclosures of the present application. the

Please refer to FIG. 7 , the twisted carbon nanotube wire is obtained by mechanically twisting the above-mentioned carbon nanotube film drawn from the superparallel carbon nanotube array. The twisted carbon nanotube wire includes a plurality of carbon nanotubes arranged helically around the carbon nanotube wire axially. Specifically, the twisted carbon nanotube wire includes a plurality of carbon nanotube segments, the plurality of carbon nanotube segments are connected end to end by van der Waals force, and each carbon nanotube segment includes a plurality of carbon nanotubes that are parallel to each other and closely combined by van der Waals force. Tube. The carbon nanotube segment has any length, thickness, uniformity and shape. The length of the twisted carbon nanotubes is not limited, and the diameter is 0.5 nanometers to 100 microns. Further, the twisted carbon nanotubes can be treated with a volatile organic solvent. Under the action of the surface tension generated when the volatile organic solvent volatilizes, the adjacent carbon nanotubes in the treated twisted carbon nanotubes are closely combined by van der Waals force, so that the specific surface area of the twisted carbon nanotubes is reduced, and the density and Increased strength. the

The carbon nanotube structure may include a composite structure composed of a carbon nanotube linear structure and a carbon nanotube film, and the at least one carbon nanotube linear structure is arranged on the surface of a carbon nanotube film or between two overlapping carbon nanotube films , so that the carbon nanotube structure has a higher strength. the

The electrodes 124 are arranged at intervals and electrically connected with the carbon nanotube structure. The amplified voltage signal is applied to the carbon nanotube structure through the electrode 124, so that an alternating current corresponding to the amplified voltage signal is generated inside the carbon nanotube structure, so that the carbon nanotube structure emits heat, heats the surrounding medium, and then emits Sound that can be perceived by the human ear. The electrode 124 is formed of conductive material, and its specific shape and structure are not limited. Specifically, the electrodes 124 can be selected to be in a layer shape, a rod shape, a block shape or other shapes. The material of the electrode 124 can be selected from metal, conductive polymer, conductive glue, metallic carbon nanotube, indium tin oxide (ITO) and the like. In the embodiment of the present invention, the at least two electrodes 124 are metal rods arranged at intervals on the surface of the carbon nanotube structure. the

Since carbon nanotubes have a large specific surface area, under the action of van der Waals force, the carbon nanotube structure itself has good adhesion, so the electrode 124 and the carbon nanotube structure can be in direct contact and The electrode 124 can be adhered and fixed to form a good electrical contact. In addition, a conductive adhesive layer can be used to adhere and fix the electrode 124 on the surface of the carbon nanotube structure. the

When the carbon nanotubes in the carbon nanotube structure are arranged in an orderly manner along a certain direction, preferably, the arrangement direction of the carbon nanotubes extends from one electrode 124 to the other electrode 124, and there should be a gap between the two electrodes 124. A substantially equal distance, so that the carbon nanotubes between the two electrodes 124 can have a substantially equal resistance. In this embodiment, the carbon nanotubes are arranged along a direction substantially perpendicular to the length of the rod-shaped electrode 124 . the

Preferably, the length of the electrode 124 is greater than or equal to the width of the carbon nanotube structure, so that the entire carbon nanotube structure can be utilized. The electrodes 124 lead the amplified voltage signal evenly into the carbon nanotube structure, and the carbon nanotubes in the carbon nanotube structure convert electrical energy into thermal energy, heat the surrounding medium, and change the density of the surrounding medium to produce sound. The medium can be a gas or a liquid. the

It can be understood that the electrode 124 is an optional structure. The output terminal 114 of the power amplifier 14 can be directly electrically connected to the carbon nanotube structure through wires or electrode leads. In addition, any connection method that can realize the electrical connection between the output terminal 114 of the power amplifier 14 and the carbon nanotube structure, and input an amplified voltage signal into the carbon nanotube structure is within the protection scope of the present invention. the

It can be understood that the thermoacoustic element 122 is not limited to the above carbon nanotube structure. Any structure capable of thermally generating sound through the conversion of "electro-thermal-acoustic" falls within the protection scope of the present invention. Specifically, the thermoacoustic element 122 should have a small heat capacity per unit area (such as less than 2×10 ⁻⁴ joules per square centimeter Kelvin), and be a conductive structure with a large specific surface area and a small thickness, so that The thermoacoustic element 122 can convert the input electric energy into heat energy, and perform heat exchange with the surrounding medium sufficiently and rapidly. Preferably, the thermoacoustic element 122 should be a self-supporting structure. The thermoacoustic element 122 of the self-supporting structure can fully contact with the surrounding medium and perform heat exchange.

Furthermore, when the power amplifier 14 cannot add a bias voltage to the amplified voltage signal output by it, in order to enable the speaker 12 to better emit normal frequency sound, the speaker system 10 may include a frequency reduction circuit 16, the The down-frequency circuit 16 reduces the frequency of the electrical audio signal sent by the audio signal source 20 , for example, doubles the frequency, and inputs the frequency to the power amplifier 14 . It can be understood that the function of the down-frequency circuit 16 can also be integrated into the circuit of the power amplifier 14 . the

The speaker system 10 may further include a plurality of speakers 12 and a frequency divider, the frequency divider is electrically connected to the output terminal 114 or the input terminal 112 of the power amplifier 14 . When the frequency divider is connected to the output terminal 114 of the power amplifier 14 , the amplified voltage signal is divided into multiple signals of different frequency bands and transmitted to multiple speakers 12 respectively. When the frequency divider is connected to the input terminal 112 of the power amplifier 14 , the frequency divider first divides the audio electric signal into multiple signals of different frequency bands, and then amplifies through multiple power amplifiers 14 . the

Since the principle of driving the thermoacoustic element 122 to sound is the conversion of "electricity-heat-acoustic", the audio electric signal can heat the thermoacoustic element 122 equivalently no matter in the positive half cycle or the negative half cycle of the energy change. Therefore, the frequency at which the thermoacoustic element 122 generates heat is twice the frequency of the audio electrical signal, that is, the sound frequency of the thermoacoustic element 122 is a double frequency. Therefore, in order to correctly restore the frequency of the audio electrical signal and make the thermoacoustic element 122 emit a sound of a normal frequency, it is necessary to down-frequency the audio electrical signal or bias the amplified voltage signal, that is, the speaker system 10 needs to include A frequency down circuit 16 or a power amplifier 14 capable of outputting a biased amplified voltage signal. If the audio signal itself has been down-converted, such as using software in the computer to down-frequency the digital signal, the audio signal can be directly amplified by a common power amplifier 14 and drive the thermoacoustic element 122 to produce sound. the

When the speaker system 10 is in use, the amplified voltage signal is transmitted to the inside of the thermoacoustic element 122 . Since the thermoacoustic element 122 has a certain resistance, when the current flows through the thermoacoustic element 122, the thermoacoustic element 122 converts electrical energy into heat energy. Since the thermoacoustic element 122 has a small heat capacity per unit area (less than 2×10 ^-4 joules per square centimeter Kelvin, preferably less than 1×10 ^-6 joules per square centimeter Kelvin), after the input signal, according to the signal intensity (such as voltage intensity), the thermoacoustic element 122 performs rapid heat exchange with the surrounding medium under the action of the audio electric signal, heats the surrounding medium according to the frequency of the audio electric signal, rapidly raises and lowers the temperature, and generates periodic The temperature changes and conducts rapid heat exchange with the surrounding medium. Due to the heating of the thermoacoustic element 122, the density of the surrounding medium changes according to the frequency of the audio signal, so that the surrounding medium expands and contracts rapidly, thereby emitting sound. The frequency range of the sound emitted by the thermoacoustic element 122 is wide (1 Hz-100 kHz), and the sound effect is good. As shown in Figure 8, the embodiment of the present invention adopts a layer of A4 paper-sized carbon nanotube film as the loudspeaker system 10 of the thermoacoustic element 122. Under the condition of an input voltage of 50 volts, a microphone is arranged on the carbon nanotube film facing the carbon nanotube film. The carbon nanotube film has a nanotube structure at a distance of 5 cm. It is measured that the sound intensity of the carbon nanotube film can reach 105 decibel sound pressure level (dBSPL), and the sound frequency range is from 100 Hz to 100,000 Hz (ie, 100 Hz to 100 kHz).

The loudspeaker system 10 provided by the embodiment of the present invention has the following advantages: First, the loudspeaker system uses the thermoacoustic element as a transducer device, and converts electrical energy into sound energy. The loudspeaker system is simple, and when the thermoacoustic element is A carbon nanotube structure has excellent properties such as light weight, small volume, high mechanical strength and high temperature resistance, so the speaker system can be used in a wide range of fields. Second, the loudspeaker system does not need other complicated structures such as magnets, so the structure of the loudspeaker system is relatively simple, which is beneficial to reduce the cost of the loudspeaker system. Thirdly, the loudspeaker system uses the external input audio signal to cause the temperature change of the thermoacoustic element, so that the surrounding medium expands and contracts rapidly, and then emits sound waves. The principle of sound generation is the conversion of "electricity-heat-acoustic", so The loudspeaker system can work under non-magnetic conditions and has a wide range of applications. Fourth, because the thermoacoustic element has a small heat capacity per unit area and a large specific surface area, after the input signal, according to the change of the signal intensity (such as the current intensity), the surrounding gas medium is evenly heated, and the temperature rises and falls rapidly. Generate periodic temperature changes, and conduct rapid heat exchange with the surrounding gas medium, so that the surrounding gas medium expands and contracts rapidly, and emits a sound that can be perceived by the human ear, and the frequency range of the sound emitted is wide (1Hz ~ 100kHz), The sound effect is better. Fifth, because the carbon nanotube structure has good mechanical strength and toughness, and good durability, it is conducive to the preparation of speaker systems of various shapes and sizes composed of carbon nanotube structures, which can be easily applied in various fields . Sixth, because the carbon nanotube structure has good transparency, it can be used as a transparent speaker in a speaker system. the

In addition, those skilled in the art can also make other changes within the spirit of the present invention. Of course, these changes made according to the spirit of the present invention should be included within the scope of protection claimed by the present invention. the

Claims (9)

1. a speaker system, it comprises:

One loud speaker; And

One power amplifier, it is amplification voltage signal by the audio electrical signal power amplification of reception that this power amplifier is used for, and drives this loud speaker sounding;

It is characterized in that: this loud speaker comprises a thermic sounding component and at least two electrode gap settings and is electrically connected to this thermic sounding component, these at least two electrodes are for inputing to this thermic sounding component by above-mentioned amplification voltage signal, this thermic sounding component comprises at least one carbon nano-tube film or at least one liner structure of carbon nano tube, this carbon nano-tube film or liner structure of carbon nano tube comprise a plurality of carbon nano-tube, this thermic sounding component, for changing the electric energy of amplification voltage signal into heat energy, changes thermic sounding component ambient density and sends sound wave.

2. speaker system as claimed in claim 1, is characterized in that, described power amplifier is further used for the additional bias voltage of this amplification voltage signal.

3. speaker system as claimed in claim 1, is characterized in that, described power amplifier comprises:

One triode, this triode has a base stage, an emitter and a collector electrode, this emitter is connected with described loud speaker one electrode;

One electric capacity, described audio electrical signal inputs to the base stage of this triode by this electric capacity;

One direct current voltage source is connected with another electrode of this loud speaker,

One first resistance, this direct voltage source is connected to the base stage of this triode by this first resistance;

One second resistance, the base stage of this triode is by this second grounding through resistance; And

One the 3rd resistance, this collector electrode is by the 3rd grounding through resistance.

4. speaker system as claimed in claim 1, is characterized in that, the unit are thermal capacitance of described thermic sounding component is less than 2 * 10 ^-4every square centimeter of Kelvin of joule.

5. speaker system as claimed in claim 1, is characterized in that, described carbon nano tube structure comprises the combination of described at least one carbon nano-tube film and at least one liner structure of carbon nano tube.

6. speaker system as claimed in claim 5, is characterized in that, described a plurality of carbon nano-tube join end to end by Van der Waals force.

7. speaker system as claimed in claim 1, it is characterized in that, described speaker system further comprises a frequency down circuit, described audio signal source is electrically connected to the input of this power amplifier by this frequency down circuit, and this frequency down circuit is used for described audio electrical signal frequency reducing and transfers to this power amplifier.

8. speaker system as claimed in claim 1, it is characterized in that, described speaker system further comprises a plurality of loud speakers and a frequency divider, and this frequency divider is electrically connected to described a plurality of loud speakers respectively and a plurality of audio electrical signals that this audio electrical signal is divided into different frequency range are transferred to respectively to the plurality of loud speaker.

9. speaker system as claimed in claim 1, is characterized in that, described speaker system further comprises an audio signal source, for generation of an audio electrical signal and be passed to described power amplifier.

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