JPS61161898A - Speaker diaphragm - Google Patents

Abstract

PURPOSE:To obtain a speaker which can cover a wide area from an intermediate frequency band to a high frequency band by laminating alternately two layers or above of a diamond or diamond-shaped carbon layer and a Si3N4 film layer. CONSTITUTION:Si3N4 of 22.0mum thick is evaporated on an M0 plate by a CVD method, and thereafter, M0 is dissolved by aqua regia and a Si3N4 plate is obtained. Next, on the Si3N4 plate, a diamond film of 5mum is covered by a plasma CVD method with a micro wave of 2.45GHz as an excitation source. When the diaphragm of 50mmphi of an Si3N4-diamond laminated construction obtained by such a method is used for the dynamic type speaker diaphragm, the sound pressure level between 10KHz-20KHz is within 1.7dB of the average value. The high frequency band frequency characteristic goes to be satisfactory compared with the fact that the error of maximum 2.4dB is found for the same type Be diaphragm.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to the structure of an 8-quality speaker diaphragm.

<Conventional technology> Various methods are used for acoustic speakers, but
Among these, dynamic speakers are the most commonly used.

This type is based on the principle of converting sound into sound using a diaphragm connected to a moving coil that moves in magnetic flux.

Paper is the most commonly used material for diaphragms, but accurate conversion becomes difficult at frequencies above several hundred hertz. In order to improve this, various diaphragm materials have been studied, and it has been found that materials with a large ratio of E/ρ, where E is Young's modulus and ρ is specific gravity, have excellent conversion characteristics in the high frequency range.

Table 1 below shows the Young's modulus (E) of various materials used as diaphragms.
, specific gravity (ρ) and (E)/(ρ).

In the above table, beryllium (B@) is used as the best material.

<Problems to be solved by the invention> Since the diaphragm is difficult to process, the diaphragm is formed by vacuum evaporation. However, considering that oxides are inherently toxic, it is difficult to process the diaphragm. It is necessary to devise ways to treat the kimono.

This is also a reason for the high price.

Although diamond has the highest E/ρ and is the ultimate material, it takes time and is economically undesirable to make a film thick enough to form a diaphragm using only diamond.

<Means for Solving the Problems> The present invention was made as a result of studies to solve the problems of the conventional speaker diaphragm materials described above.

That is, the present invention is a speaker diaphragm characterized by comprising a diamond or diamond-like carbon film layer and s = 3NJ m, and is made of two different materials.
A new diaphragm with improved performance is provided by alternately laminating multiple layers.

<Function> Looking at the configuration of the diaphragm of this invention, one is made of diamond, which is the ultimate material for a diaphragm, and the other is S=
It is to use zNJr.

S = 3N cow has a high Young's modulus, but its density is 4, which is higher than beryllium, so E/ρ has a lower value than beryllium. However, since it is one of the materials whose Young's modulus is closest to that of diamond, this S
The combination of i sN* and diamond is considered to be the most suitable combination for a diaphragm.

In this invention, both the diamond layer and the SL sNJ are synthesized from the gas phase.

Since the deposition rate is generally faster than that of SLs-diamond, it is more economical than forming a diaphragm made of diamond alone, and from this point of view as well, the effects of the present invention can be recognized.

As is well known, diamond film is produced by CVD method, plasma CV method.
It can be obtained by any method such as the D method or the ion beam evaporation method, and there is no difference in the properties of the obtained fibers.

In addition, an amorphous carbon film (so-called i-Qarbon film) obtained by plasma CVD method or ion beam evaporation method
), but there is no big difference in performance.

SL 5NJA CVD method, plasma CVD method,
You can create it using any method, such as the ion brating method (there is no big difference in performance either).

Example of implementation The present invention will be explained below with reference to Examples.

Example 1 Si 3N't was deposited at 22.0 on a ratio plate using a known CVD method.
After steaming to a μm thickness, the ceramic was dissolved in aqua regia to obtain Si 3N and a plate.

Next, a diamond film having a thickness of 5 μm was coated on the Si 4 plate by plasma CVD using a 2.45 G)-12 microwave as an excitation source.

50 of the thus obtained SL3Ng-diamond laminated structure.
When a mmφ diaphragm was used as a diaphragm for a dynamic speaker, the diaphragm was 10,000 to 20,0008
The sound pressure level between z was within 1.7d3 of its average value.

On the other hand, a maximum error of 2.4 dB was observed for the &diaphragm of the same diameter.

Example 2 SL d was applied to an aluminum plate by a known plasma CVD method.
The K film was formed into a 32 μm film by stacking 20 layers of i-carbon group layers alternately with a thickness of 1 μm and 0.3 μm each using a known ion beam evaporation method.
A thick diaphragm was obtained.

When the thus obtained diaphragm was tested with a diameter of 50 mm in the same manner as in Example 1, only an error of 1,463 occurred.

<Effects of the Invention> As mentioned above, the diaphragm of the present invention has excellent frequency characteristics, especially in roaring sounds, and therefore can be used as a speaker that can cover a wide range from the midrange to the treble range. .

Claims (2)

[Claims] (1) A speaker diaphragm comprising a diamond or diamond-like carbon film layer and a Si_3N_4 film layer. (2) The speaker diaphragm according to claim 1, characterized in that two or more diamond or diamond-like carbon film layers and Si_3N_4 film layers are alternately laminated.