JPS63288600A - Diaphragm for loudspeaker - Google Patents

Abstract

PURPOSE:To obtain a loudspeaker use diagram having excellent sound pressure- frequency characteristic, distortion rate and phase characteristic, by forming a thin film consisting of carbon on a metallic loudspeaker diaphragm board, and also, forming a silicone carbide thin film on its thin film. CONSTITUTION:On a metallic loudspeaker diaphragm board, a thin film consisting of carbon is formed. Also, on this thin film, a silicon carbide thin film is formed. As for a loudspeaker which has used a diaphragm which is formed in such a way, a growth speed of the silicon carbide thin film is high due to an effect of the carbon thin film, therefore, it is excellent in its mass-producing property. Also, both carbon and silicon carbide consist of a diamond structure, therefore, this loudspeaker use diaphragm has a very large fluxural rigidity, and in the course of vibration, the diaphragm is not deformed and the split resonance is not generated, and an excellent loudspeaker use diaphragm having excellent sound pressure-frequency characteristic, distortion rate and phase characteristic can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a diaphragm for a speaker used as an audio output device.

Conventional technology In recent years, in the cassette tape recorder, micro cassette tape recorder, and high-fidelity stereo industries, speakers and beakers have been developed that have even better output sound pressure, distortion rate, and flatness than before in terms of the acoustic characteristics of speakers used as audio output equipment. As a result, speaker diaphragms, which influence acoustic characteristics, are becoming more and more important.

The conventional speaker mentioned above will be explained below.

Conventional speakers have a diaphragm and a voice coil bobbin.

It consists of a vibration system such as a voice coil, and a magnetic circuit system consisting of a magnet, pole, plate, and yoke. When an audio current flows through a voice coil in a uniform magnetic field, a vertical electromagnetic force is generated in the voice coil, causing it to vibrate in response to the current. This vibration is properly transmitted to the diaphragm and emitted as a sound wave (for example, Hisao Hayasaka: Introduction to Acoustic Engineering, Nikkan Kogyo Shimbun).

Problems to be Solved by the Invention However, it is ideal for the diaphragm of a speaker to make a piston movement over the frequency band used, and if the diaphragm deforms during vibration or split imaging occurs, the sound pressure-frequency characteristics and distortion will be affected. The rate two-phase characteristics and the like deteriorate, which impedes high-fidelity reproduction. Further, since the metal imaging plate material has a small E/ρ (E: elastic modulus, ρ: density), the high-frequency resonance frequency is low, and the speaker cannot reproduce high frequencies. For this reason, the SiC thin film is formed on the metal speaker diaphragm base, which prevents the 9-division vibration in which the diaphragm deforms during vibration.
Although this proposed method provided a speaker diaphragm with a high high resonance frequency, it had the drawback that it took time to generate a silicon carbide thin film.

In view of the above-mentioned problems, the present invention provides a diaphragm for a speaker that shortens the time for forming a thin film, does not deform the diaphragm during vibration, does not cause split vibration, and has a high high-frequency resonance frequency.

Means for Solving the Problems In order to achieve this object, the speaker diaphragm of the present invention has a thin film made of carbon formed on a metal speaker diaphragm base, and a silicon carbide thin film on the thin film. The resulting molded product is used as a diaphragm.

Function: This speaker diaphragm has a thin film of carbon formed on the metal speaker diaphragm base, so the growth rate of silicon carbide is faster than when silicon carbide is directly formed on the metal speaker diaphragm base. becomes 6 times. Furthermore, since carbon and silicon carbide both have a diamond structure, this speaker diaphragm has extremely high bending rigidity, and the diaphragm does not deform during vibration or split resonance occurs, resulting in excellent sound pressure-frequency characteristics and distortion. It has a two-phase characteristic and is suitable as a speaker diaphragm. Furthermore, carbon with a melting point of 36oO℃ is used to generate thin films using the CVD method.

The same 2700℃ silicon carbide can be produced at a lower temperature, and a thin film can be produced on any diaphragm shape, and the thickness can be adjusted freely, so it can be used not only for flat diaphragms but also for dome-shaped diaphragms and other shapes. It can be processed freely and any acoustic characteristics can be obtained.

EXAMPLE A speaker diaphragm according to an example of the present invention will be described below.

A speaker diaphragm according to an embodiment of the present invention is a speaker diaphragm in which a thin film made of carbon is formed on a metal speaker diaphragm base, and a silicon carbide thin film is further formed on the thin film. A speaker is formed by inserting the voice coil at the end of the voice coil bobbin whose tip is fixed to the diaphragm into the magnetic gap of the magnetic circuit and vibrating it.

A method of manufacturing the speaker imaging plate configured as described above will be described below.

First, silane compounds (D, D, S, etc.) are used as raw materials.

TMS, etc.), with hydrogen as the reducing gas, flowed into a heated reactor. A metal speaker diaphragm base is installed in advance in the reactor, and reduced carbon and silicon carbide are accumulated in the reactor. In order to generate a thin carbon film on the metal speaker diaphragm base,
The raw material was chilled to 0°C and the vapor pressure was adjusted to form a 10 μm thick carbon film. Continuing further, the SOC of raw materials
A molded product in which a 40 μm thick silicon carbide thin film was formed on a carbon thin film was used as a speaker diaphragm.

As described above, according to this embodiment, a speaker using a diaphragm in which a thin film made of carbon is formed on a metal speaker diaphragm base, and a silicon carbide thin film is further formed on the thin film, Due to the effect of the carbon thin film, the growth rate of the silicon carbide thin film is fast and it is excellent in mass production. In addition, since carbon and silicon carbide have a diamond structure, the speaker diaphragm has extremely high bending rigidity, and the diaphragm does not deform during vibration or split resonance occurs, resulting in excellent sound pressure-frequency characteristics and distortion rate. It has one-phase characteristics.

Effects of the Invention As described above, the present invention provides a method for using a molded product in which a thin film of carbon is formed on a metal speaker diaphragm base and a thin silicon carbide film is further formed on the thin film as a pickup plate for a speaker. It is a material that can be easily mass-produced, has a high resonance frequency due to the effects of carbon and silicon carbide, and can realize an excellent speaker with good acoustic characteristics.

Claims (1)

[Claims] A speaker diaphragm in which a thin film made of carbon is formed on a metal speaker diaphragm base, and a silicon carbide thin film is further formed on the thin film.