Background technique
Microphone is sound-electric conversion equipment, also referred to as " microphone ", " microphone " etc..It is most attached most importance in sound systemA kind of one of electro-acoustic element wanted, its effect are to convert acoustic signals into electric signal, then be sent to sound console or amplifier, finallyIt is played back from speaker system.That is, microphone is for picking up sound in the acoustic system, it is entire sound equipmentFirst link of system, the quality of performance quality, the influence to entire sound system are very big.
There are many type of microphone, can be divided into electrodynamic type, condenser type, electromagnetic type, piezoelectric type, semiconductor-type by transduction principleMicrophone.
The problem of common microphone has at present:
1, sensitivity is low: the sensitivity of microphone refers to the sound of microphone -- the ability of electrotransformation.Common moving-coil passesFor the sensitivity of sound device generally in -60dB or so, higher have-a 50dB, and the highly sensitive microphone of profession can achieve -40dB or so.
Highly sensitive microphone can pick up bigger sound under identical condition, thus can reduce rear class and putThe burden of big device, is easy to get high signal-to-noise ratio.
2, close effect: the close effect of microphone is its low frequency sensitivity meeting when microphone is in short distance pickupApparent to improve, distance is closer, and low frequency output is bigger.The effect of low frequency, this low coverage is stronger.
Close effect destroys the good frequency response of microphone, that is to say, that after this microphone, in original sound fieldLow frequency part can abnormal increase.
3, it is limited to bear acoustic pressure: excessive acoustic pressure can make microphone pickup quality bad, and be possible to damage microphone, becauseThis microphone has the technical indicator of one " maximum can bear acoustic pressure ".
Summary of the invention
In order to overcome the sensitivity of existing microphone is low, be not durable the features such as, the invention proposes a kind of microphones.It shouldMicrophone applies the excellent physical characteristic jumpy of resistance value caused by the unique miniature deformation of carbon nanotube, cooperationCurrent source or voltage source make sound signal be changed into voltage or current signal, thus completion sound-electricity conversion.
To achieve the above object, the present invention provides a kind of microphone, including vibrating diaphragm load and detection circuit, the vibrating diaphragmsLoad includes shaking membrane substrate, and is coated on the carbon nanotube coating on the shaking membrane substrate surface, for receiving extraneous audio frequency letterAfter number, it is converted into the electric signal of variation；Detection circuit, for detecting voltage or curent change in the vibrating diaphragm load, andExtract the sound signal.
Preferably, the carbon nanotube coating is coated on one side or the two sides of the shaking membrane substrate.
Preferably, the shaking membrane substrate has gossamery elastic material.
It preferably, further include current source or voltage source.
Preferably, the detection circuit, further includes: amplifier, what the amplifier was used to generate vibrating diaphragm loadElectric signal amplifies.
Microphone proposed by the present invention uses the membrane parts of carbon nanotube spraying, and the unique miniature deformation of carbon nanotube drawsThe excellent physical characteristic jumpy of the resistance value risen, structure is simple, reduce close effect, acoustic pressure is born in raising and transaudientThe sensitivity of device, and good weatherability, it is not afraid of vibratory impulse and wet environment；Amplifier in peripheral detection circuit, because directly mentioningThe variable signal of voltage or electric current is taken, amplifying circuit is easy to optimize, is stable and efficient, is conducive to the implementation of technique.
Specific embodiment
To make the technical solution of the embodiment of the present invention and becoming apparent from for advantage expression, below by drawings and examples,Technical scheme of the present invention will be described in further detail.
Fig. 1 is a kind of microphone circuit structure chart using current source of the embodiment of the present invention.As shown in Figure 1, the present invention mentionsA kind of microphone is gone out, comprising: power supply, current source, vibrating diaphragm load and detection circuit.
In microphone circuit, positive pole connects one end of current source, the other end connection vibrating diaphragm load of current sourceThe other end ground connection of one end, power cathode and vibrating diaphragm load, one end of detection circuit are connected between vibrating diaphragm load and current source.After vibrating diaphragm load-receipt is to extraneous sound signal, resistance changes in vibrating diaphragm load, stablizes electricity since current source providesStream, the voltage for causing vibrating diaphragm to load change, the voltage change amplified in detection circuit detection vibrating diaphragm load, and extract instituteState sound signal.
Wherein, in microphone, the voltage of power supply is sometimes unstable, increases a current source in circuit, by mentioningFor stabling current, make microphone not by the voltage influence of power supply.The sensitivity of microphone is improved in this way.
In addition, as shown in Fig. 2, detection circuit further includes an amplifier.The peripheral circuit of carbon nanotube microphone circuitIt can connect an amplifier, since change in electric is smaller in microphone circuit, carried out electric signal with an amplifierAmplification.Because directly extracting the variable signal of voltage or electric current, amplifying circuit is easy to optimize, is stable and efficient, and peripheral circuitSimply, cost is reduced.
Specifically, current source can be replaced with voltage source.As shown in figure 3, the invention also provides a kind of microphone, packetIt includes: power supply, voltage source, vibrating diaphragm load, resistance, amplifier and detection circuit.
In microphone circuit, positive pole connects one end of voltage source, the other end connection vibrating diaphragm load of voltage sourceOne end, the other end of vibrating diaphragm load connect resistance, and the other end ground connection of power cathode and resistance, one end of amplifier is connected to vibrationBetween film load and resistance, the other end of one end connection amplifier of detection circuit.When vibrating diaphragm load-receipt to extraneous audio frequency letterAfter number, resistance changes in vibrating diaphragm load, and since voltage source provides burning voltage, the electric current for causing vibrating diaphragm to load becomesChange, amplifier amplifies electric signal, the curent change amplified in detection circuit detection vibrating diaphragm load, and extracts the soundFrequency signal.
Fig. 4 is the structure chart of vibrating diaphragm of the present invention load.As shown in figure 4, vibrating diaphragm load includes shaking membrane substrate and carbon nanotubeCoating, carbon nanotube coating are coated on the surface of shaking membrane substrate, for extraneous sound signal to be converted into electric signal.
Specifically, carbon nanotube coating has resistance value, the urgency of resistance value caused by the unique miniature deformation of carbon nanotubeThe excellent physical characteristic of drastic change, makes sound signal be changed into electric signal, to complete sound-electric conversion.This carbon nanotubeMicrophone greatly improves the sensitivity of microphone, and carbon nanotube has good stability, so using carbon nanometerThe microphone good weatherability of pipe is not afraid of vibratory impulse and wet environment.
Wherein, carbon nanotube coating can be coated on one side or the two sides of shaking membrane substrate using spraying or other modes.
Specifically, shaking membrane substrate has gossamery elastic material.The shaking membrane substrate be with gossamery elastic material,Carbon nanotube coating is coated on the surface of shaking membrane substrate, and when sound wave causes its vibration, shaking membrane substrate is by extraneous vibrationIt is dynamic and when being deformed, the resistance value of carbon nanotube coating can regular variation therewith, the current source or voltage source of utilizationThe voltage signal or electric current number of available variation.The structure for simplifying vibrational system in this way, is conducive to the implementation of technique.
In present example, each module realizes microphone function by operation as follows.
Power supply, current source, vibrating diaphragm load, amplifier and detection circuit in carbon nanotube microphone circuit, by Fig. 2 connection sideFormula connection, wherein power cathode and the other end of vibrating diaphragm load are grounded respectively.
When microphone works, electric current comes out from positive pole, loads followed by current source and vibrating diaphragm, forms a stabilizationCircuit.When vibrating diaphragm load receives extraneous sound signal, sound wave causes shaking membrane substrate vibration in vibrating diaphragm load, is coated on vibrating diaphragm baseThe resistance of carbon nanotube coating changes with vibration on material, since current source provides stable electricity in microphone circuitStream, changes so as to cause vibrating diaphragm load voltage.The voltage that sound signal is converted into variation is completed in vibrating diaphragm load at this timeSignal.
Carbon nanotube microphone peripheral circuit connects an amplifier, since voltage signal is smaller in microphone circuit,By an amplifier, voltage signal is amplified, then be sent to detection circuit, for detecting the voltage in the vibrating diaphragm loadVariation, and extract wherein sound signal.
Microphone proposed by the present invention uses the membrane parts of carbon nanotube spraying, and the unique miniature deformation of carbon nanotube drawsThe excellent physical characteristic jumpy of the resistance value risen, structure is simple, reduce close effect, acoustic pressure is born in raising and transaudientThe sensitivity of device, and good weatherability, it is not afraid of vibratory impulse and wet environment；Amplifier in peripheral detection circuit, because directly mentioningThe variable signal of voltage or electric current is taken, amplifying circuit is easy to optimize, is stable and efficient, is conducive to the implementation of technique.
Above-described specific embodiment has carried out further the purpose of the present invention, technical scheme and beneficial effectsIt is described in detail, it should be understood that being not intended to limit the present invention the foregoing is merely a specific embodiment of the inventionProtection scope, all within the spirits and principles of the present invention, any modification, equivalent substitution, improvement and etc. done should all includeWithin protection scope of the present invention.