TWI469647B - Acoustic device - Google Patents

Description

Sound device

The present invention relates to a sound emitting device, and more particularly to a sound emitting device using an alloy casing.

With the continuous development of new technologies and new materials, people's requirements for audio-visual quality are getting higher and higher. Sounding devices, such as earphones and stereos, have emerged in an endless stream. However, the improvement in sound quality of the sounding in the prior art has focused more on the improvement of the built-in speaker, and the improvement on the housing is less. However, the response of the housing to the sound quality is also very large, directly affecting the effect of the speaker.

Taking the earphone as an example, the housing has many effects on the sounding effect of the speaker and the whole earphone due to resonance and reverberation. The earphone housing in the prior art is plastic or resin, which causes the reverberation of the earphone to be long, and the housing is The resonance is strong, the sound effect is not clear enough, and the earphone has a problem of poor sound quality. In addition, plastic or resin housings are not durable, easily deformed, and not lightweight enough.

A sounding device comprising: a housing; and a speaker disposed inside the housing; the material of the housing is a magnesium-based composite material comprising a magnesium-based metal and dispersed in the magnesium-based metal The nano-reinforced phase has a grain size of from 100 micrometers to 150 micrometers.

Compared with the prior art, the technical solution adopts a magnesium-based composite material as a sounding device. The housing can reduce the reverberation and resonance generated by the housing, so that the sounding effect is clear, thereby improving the sound quality of the sounding device. Moreover, the shell of the magnesium-based composite material is more durable and durable than the plastic shell. Since the shell has good strength, a small wall thickness can be used under the premise of meeting the strength requirement, thereby reducing the overall sounding device. Quality and increase the internal space of the sounding device.

10‧‧‧ headphones

12‧‧‧ Front

14‧‧‧Speaker

16‧‧‧ Rear

FIG. 1 is a schematic structural diagram of an earphone according to an embodiment of the present technical solution.

Figure 2 is a 50x optical microscope photograph of AZ91D magnesium alloy.

Figure 3 is a 50x optical micrograph of a magnesium-based composite material having a nano-weighted phase of 0.5% by mass.

Figure 4 is a 50x optical micrograph of a magnesium-based composite having a nano-weighted phase of 1% by mass.

Figure 5 is a 50x optical micrograph of a magnesium-based composite having a nano-mass phase of 1.5% by mass.

Figure 6 is a high-resolution transmission electron micrograph of the tantalum carbide and magnesium grain interface in a magnesium-based composite.

Fig. 7 is a test data diagram of tensile strength of a magnesium-based composite material having different mass percentages of nano-reinforced phase.

Fig. 8 is a graph showing the test data of the elongation of the magnesium-based composite material having different mass percentages of the nano reinforcing phase.

Figure 9 is a graph showing the total harmonic distortion curve test data of the earphones of the earphone housings having different materials.

Figure 10 is a waterfall analysis diagram of an earphone with a plastic earphone housing.

Figure 11 is a waterfall analysis diagram of an earphone with an AZ91D magnesium alloy earphone housing.

Figure 12 is a waterfall analysis diagram of an earphone having a magnesium-based composite earphone housing.

Hereinafter, the sound emitting device of the embodiment of the present technical solution will be described in detail with reference to the accompanying drawings.

The technical solution provides a sounding device, which comprises a hollow casing and a speaker disposed inside the casing. The sounding device can be a headset, an audio, a speaker, a cell phone, a laptop or a television.

Referring to FIG. 1 , the embodiment of the present invention takes the earphone 10 as an example. The earphone 10 includes a hollow earphone housing and a speaker 14 disposed inside the casing. The earphone 10 can be of a head-mounted, ear-hook type, in-ear type or earbud type.

The speaker 14 can be of the electric, capacitive, electrostatic, pneumatic, and piezoelectric type. The speaker 14 is used to convert an electrical signal into a sound signal. Specifically, the speaker 14 can convert a range of audio electric power signals into a audible sound having a small distortion and a sufficient sound pressure level by a transducing mode. In the present embodiment, the speaker 14 is an electric speaker 14.

The housing has a wall thickness of from 0.01 mm to 2 mm. The housing can include a front portion 12 facing the user and a rear portion 16 connecting the wires, the front portion 12 can further include a plurality of sound holes. In this embodiment, the earphone is an earbud type, the front portion 12 is a wafer cover body having a sound hole, and the rear portion 16 is a bowl-shaped base that is engaged with the wafer cover body.

At least one of the front portion 12 and the rear portion 16 of the housing is made of a magnesium-based composite material. In this embodiment, the housing is entirely made of a magnesium-based composite material, that is, a wafer cover body and a bowl. The material of the shaped base is a magnesium-based composite material. The magnesium-based composite material includes a magnesium-based metal and a nano-reinforced phase dispersed in the magnesium-based metal. The nano reinforcing phase may be a carbon nanotube, a cerium carbide nanoparticle, an alumina nanoparticle, a titanium carbide nanoparticle, a boron carbide nanoparticle, a graphite nanoparticle or a mixture thereof, preferably a carbon nanotube. Or carbonized nano particles. The carbon nanotubes may be 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. The nano reinforcing phase has a mass percentage in the magnesium-based composite of from about 0.01% to about 10%, preferably from about 0.5% to about 2%. The shape of the nano reinforcing phase can be powder, fiber or whisker. The size of the nano reinforcing phase (i.e., the diameter of the powder, fiber or whisker) is from about 1 nanometer to about 100 nanometers, preferably from 30 nanometers to 50 nanometers. The magnesium-based metal is pure magnesium or a magnesium alloy. The magnesium alloy includes, in addition to magnesium, one or more alloying elements such as zinc, manganese, aluminum, zirconium, hafnium, lithium, silver, calcium, etc., wherein magnesium accounts for more than 80% by mass of the magnesium alloy, and other metal elements The total amount of magnesium alloy is less than 20% by mass. The type of the magnesium alloy may be AZ91, AM60, AS41, AS21, AE42, preferably AZ91.

The addition of the nano reinforcing phase facilitates the refinement of the magnesium-based metal grains and can improve the tensile strength and elongation of the shell. In this embodiment, the magnesium-based metal is a magnesium alloy of the AZ91D type, and the nano-reinforced phase is made of a carbon nanotube or a strontium carbide nanoparticle. Referring to Figures 2 to 5, the grain-like comparison of the magnesium-based composite material with 0.5%, 1%, and 1.5% by weight of the nano-reinforced phase with the pure AZ91D magnesium alloy is found to be consistent with the mass percentage of the nano-reinforced phase. Gradually increasing in the range of 0.5% to 1.5%, the grain size of the magnesium-based composite material is remarkably reduced. The grain of the magnesium-based composite material is reduced by 60% to 75% compared to the grain of the magnesium-based metal used to make the magnesium-based composite material. The magnesium matrix composite has a grain size of about 100 microns to 150 microns. In this embodiment, when the nano-reinforced phase of the magnesium-based composite material is a carbon nanotube having a mass percentage of 0.5% to 2%, the grain size of the magnesium-based composite material may be smaller than that of the AZ91D magnesium alloy. 60% to 75%. Referring to FIG. 6, when the nano-reinforced phase of the magnesium-based composite material is 0.5% to 2% by mass of niobium carbide, the interface between the magnesium crystal grains and the niobium carbide crystal grains is clear, and there is no inter-interface reaction. Intermediate phase. Referring to Figure 7, the tensile strength test of the magnesium-based composite material with different nanometers of carbon nanotubes is carried out. It is found that when the carbon nanotubes account for 1.5% by mass of the magnesium-based composite material, The magnesium matrix composite has good tensile strength.

Referring to FIG. 8 , the elongation test of the magnesium-based composite material with nanometer reinforcing phase as different mass percentages of carbon nanotubes is tested, and it is found that when the carbon nanotubes account for 1.5% by mass of the magnesium-based composite material, Magnesium based composites have good elongation. The above test shows that by adding a nano reinforcing phase to the magnesium-based metal, the crystal grains are effectively refined, and the tensile strength and elongation of the magnesium-based composite material are improved, which is advantageous for the manufacture of the earphone housing and is advantageous. To improve the strength and durability of the earphone housing, please refer to Table 1 for specific test data.

The manufacturing method of the casing may be thixoforming, die casting, powder metallurgy or mechanical forming. Specifically, the powder, fiber or whisker of the nano reinforcing phase may be added to the molten magnesium-based metal, and the earphone casing may be obtained by a thixoforming or die casting method, or the magnesium-based metal powder may be obtained. Mixed with the nano reinforcing phase, The earphone casing is prepared by a powder metallurgy method. In addition, the magnesium matrix composite material may be preformed into a blank body, and the earphone casing may be formed by mechanical processing.

In this embodiment, the method for preparing the magnesium-based composite material comprises the steps of: firstly, providing a magnesium-based metal and a nano-reinforced phase; and secondly, adding the nano-reinforced phase to the molten magnesium-based metal at 460 ° C to 580 ° C; Mixing to form a mixture; again, ultrasonically treating the mixture at 620 ° C to 650 ° C to uniformly disperse the nano reinforcing phase in the magnesium-based metal; and finally, casting the mixture at 650 ° C to 680 ° C to form Magnesium based composite body.

The temperature in the above mixing, ultrasonic treatment and casting process is gradually increased in three stages, which is advantageous for grain refinement in the magnesium-based composite material, and the above processes are all carried out in a protective gas to prevent magnesium-based metal. Oxidized. The shielding gas may be selected from one or more of an inert gas and nitrogen, and the shielding gas in this embodiment is preferably nitrogen.

Specifically, the magnesium-based metal may be an AZ91D magnesium alloy, and the nano reinforcing phase may be a carbon nanotube or a tantalum carbide. The molten magnesium-based metal may be disposed in a container filled with a protective gas. In the process of adding the nano reinforcing phase to the molten magnesium-based metal, the mixture in the vessel may be further mechanically stirred by a stirrer to initially mix the nano reinforcing phase and the molten magnesium-based metal to obtain a mixed pulp. material.

The ultrasonic treatment process may be that the mixture and the container are placed in a high-energy ultrasonic vibration stirring device, and after shaking for a certain period of time, the ultrasonic wave is obtained. Mix the slurry evenly. The frequency of the ultrasonic waves is from 15 kHz to 20 kHz, and the frequency of the ultrasonic waves in the present embodiment is preferably 15 kHz. The time of the ultrasonic treatment is from 5 minutes to 40 minutes, preferably 30 minutes. The ultrasonic frequency of the ultrasonic vibration used in the technical solution is selected to be 15-20 kHz, and the frequency of the ultrasonic wave used in the technical solution is low compared to the general ultrasonic frequency of 48 kHz, and the ultrasonic oscillating device is a high energy. The ultrasonic oscillating stirring device has a large amplitude, so that the light metal particles in the light metal melting soup can be vigorously moved, so that the nano-sized particle reinforcing body can be evenly distributed in the light metal melting soup to obtain a uniform mixture. Slurry.

The mixed slurry can be cast into a mold for cooling and solidification during casting to form the magnesium-based composite body. Further, the magnesium-based composite material body can be processed by an extrusion process. Through the extrusion process, the nano reinforcing phase is redistributed in the mixture, and the dispersion is more uniform, which further improves the strength and toughness of the magnesium-based composite.

The blank can be further formed by die casting to obtain the earphone housing. The carbon nanotube was used as the nano reinforcing phase, the AZ91D magnesium alloy was used as the magnesium-based metal, and the mass percentage of the nano reinforcing phase was 1.5%, and the shell was prepared by a die casting method. Referring to Table 2, the shell made of the magnesium-based composite material has better yield strength than the plastic shell and the AZ91D magnesium alloy shell, and the density is lower than that of the AZ91D magnesium alloy.

Under the condition of using the same shape of the casing, the earphone of the casing using the magnesium-based composite material is acoustically tested, and compared with the earphone of the AZ91D magnesium alloy casing and the earphone of the plastic casing, the magnesium matrix composite is used. The earphone made of the material casing has a substantially identical frequency response curve and impedance curve with the earphone with the AZ91D magnesium alloy casing and the earphone with the plastic casing. However, referring to Figure 9, the earphone made of the housing of the magnesium-based composite material has the smallest total harmonic distortion in the three tested headphones. In the frequency range of 20 Hz to 50 Hz, the total harmonic distortion of the earphone using the housing of the magnesium-based composite material is reduced by about 10% compared to the earphone of the AZ91D magnesium alloy casing.

Referring to Figures 10 through 12, it can be seen from the waterfall analysis of housings with different materials that in the range of 20 Hz to 30 Hz, the headphone audio amplitude of the magnesium-based composite housing is the lowest, thus making the headphones The total harmonic distortion is the smallest, and in the range of 100 Hz to 600 Hz, the earphones using the magnesium-based composite casing are more uniform than the other two types of earphones, and it is known that the earphones have the characteristics of clear sounding effect.

The technical scheme adopts the magnesium-based composite material as the casing of the earphone, can shorten the reverberation of the sound of the earphone, reduce the resonance of the earphone casing, and make the sounding effect clear, thereby improving the sound quality of the earphone. Moreover, the shell of the magnesium-based composite material is more durable and durable than the plastic shell. Since the shell has good strength, a small wall thickness can be adopted under the premise of meeting the strength requirement, thereby reducing the overall quality of the earphone. And increase the internal space of the headphones. In addition, the magnesium-based composite material has good thermal conductivity, which is advantageous for heat dissipation of the earphone.

It will be understood by those skilled in the art that although the present invention is described with the earphone as a specific embodiment, since the housing has the above advantages due to the material itself for manufacturing the housing, other sounding devices having the housing can also have Good sound quality, light weight, durable and easy to dissipate heat.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. please. 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‧‧‧ headphones

12‧‧‧ Front

14‧‧‧Speaker

16‧‧‧ Rear

Claims (12)

A sounding device comprising: a housing; and a speaker disposed inside the housing; the improvement is that the material of the housing is a magnesium-based composite material comprising a magnesium-based metal and uniformly dispersed A nano-reinforced phase in the magnesium-based metal having a grain size of from 100 micrometers to 150 micrometers. The sounding device of claim 1, wherein the sounding device has a total harmonic distortion in a frequency range of 20 Hz to 50 Hz than a sounding device of the same shape of a casing made of the magnesium-based metal Reduce by 10%. The sounding device of claim 1, wherein the grain size of the magnesium-based composite material is reduced by 60% to 75% compared to the grain size of the magnesium-based metal. The sounding device of claim 1, wherein the nano-reinforced phase has a mass percentage of 0.01% to 10% in the magnesium-based composite material. The sounding device according to Item 1, wherein the nano-reinforced phase has a mass percentage of 0.5% to 2% in the magnesium-based composite material. The sounding device of claim 1, wherein the nano-reinforced phase has a mass percentage of 1.5% in the magnesium-based composite material. The sounding device of claim 1, wherein the nano-enhanced phase has a size of 30 nm to 50 nm. The sounding device according to Item 1, wherein the nano reinforcing phase is a carbon nanotube, a cerium carbide nanoparticle, an alumina nanoparticle, a titanium carbide nanoparticle, a boron carbide nanoparticle, A mixture of one or more of the graphite nanoparticles. The sounding device of claim 1, wherein the magnesium-based metal is magnesium or a magnesium alloy. The sounding device of claim 9, wherein the magnesium alloy is of the type AZ91, AM60, AS41, AS21 or AE42. The sounding device according to any one of claims 1 to 3, wherein the magnesium-based metal is a magnesium alloy of the type AZ91D, and the nano reinforcing phase is a carbon nanotube, the nanocarbon The mass percentage of the tube in the magnesium matrix composite was 1.5%. The sounding device of claim 1, wherein the housing has a wall thickness of 0.01 mm to 2 mm.