JPH0793758B2 - Vibration plate for speakers - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm for a speaker used in an acoustic output device or the like.

2. Description of the Related Art In recent years, cassette tape recorders, microcassette tape recorders, and in the hi-fi stereo industry, a speaker that is superior in output sound pressure, distortion rate, and flatness to the acoustic characteristics of a speaker as an acoustic output device is desired. The diaphragm for speakers, which influences the acoustic characteristics, is becoming more and more important.

The operation of the above-mentioned conventional speaker will be described below. The speaker is a diaphragm, voice coil bobbin,
It consists of a vibration circuit such as a voice coil and a magnetic circuit system consisting of a magnet, a pole, a plate and a yoke.

When a voice current flows through a voice coil in a uniform magnetic field, a vertical electromagnetic force is generated in the voice coil and vibrates according to the current. This vibration is correctly transmitted to the vibration of the diaphragm and emitted as a sound wave (for example, Toshio Hayasaka: Introduction to Acoustic Engineering, Nikkan Kogyo Shimbun).

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, it is ideal that the diaphragm of the speaker makes a piston motion over the frequency band used, but if the diaphragm is deformed or divided vibration occurs during vibration, the sound pressure-frequency characteristic is generated. , The distortion rate, the phase characteristics, etc. are deteriorated, which hinders high fidelity reproduction. Also, conventional paper cone diaphragms and plastic diaphragms have E / ρ (where E: elastic modulus,
Since ρ: density) is small, there is a drawback that the high frequency resonance frequency is low and the speaker cannot reproduce up to the high frequency range.

In view of the above problems, the present invention provides a speaker diaphragm having a high high resonance frequency, which does not cause the diaphragm to deform or generate divided vibration during vibration.

Means for Solving the Problems In order to achieve this object, a speaker diaphragm of the present invention uses a molded product obtained by coating a plastic film with urushiol, which is a phenol derivative, and transferring the pulp to pulp. It is a thing.

Action The present invention has a very large elastic modulus due to the above-mentioned configuration,
When this is used as a vibration plate, the bending rigidity of the vibration plate is very large, and the vibration plate is not deformed or split resonance does not occur during vibration. In addition, since kraft pulp is used as the base material and the above-mentioned urushiol is laminated on it, the specific elastic modulus
E / ρ (however, E: elastic modulus, ρ: density) is large, and when this is used as a diaphragm, the reproduction band of the speaker is extended and the speaker has excellent sound pressure-frequency characteristics, distortion rate, and phase characteristics. Can be obtained.

Also, because this diaphragm material uses urushiol, which is a phenol derivative, as a laminated material, it has excellent solvent resistance, water resistance, and heat resistance, so it can withstand use of the speaker under extremely severe conditions. .

Example Hereinafter, a speaker diaphragm according to an example of the present invention will be described.

The speaker in one embodiment of the present invention uses a diaphragm in which urushiol, which is a phenol derivative, is coated on a plastic film and transferred to pulp. This diaphragm is fixed to the voice coil bobbin, and the voice coil provided at the tip of the voice coil bobbin is inserted in the magnetic gap of the magnetic circuit.

The operation of the speaker configured as above will be described below.

The speaker includes a vibration system such as a diaphragm, a voice coil bobbin, and a voice coil, and a magnetic circuit system including a magnet, a pole, a plate, and a yoke. When a voice current flows through a voice coil in a uniform magnetic field, a vertical electromagnetic force is generated in the voice coil and vibrates in response to the current. This vibration is correctly transmitted to the vibration of the diaphragm and is emitted as a sound wave.

Next, the manufacturing method of the diaphragm is described. A phenol derivative, urushiol, is coated on a polyester film having a thickness of 100 μm to a thickness of 50 μm, and the temperature is 80 ° C. for 30 hours.
It is cured to the B-stage state under the condition of min.

After that, this film was transferred to a basis weight of 25 g / m ² kraft pulp at a temperature of 100 ° C., a pressure of 10 kg / cm ² , and a time of 10 min.
It is molded into a dome-shaped diaphragm with a diameter of 30 mm.

As described above, according to the present embodiment, the speaker using the diaphragm in which the phenol derivative urushiol is coated on the plastic film and then transferred to the pulp has good acoustic characteristics without deformation of the diaphragm and split resonance. As a result, the distortion rate can be reduced by 23 dB as compared with the aluminum dome type diaphragm having the same shape. Moreover, the high frequency resonance frequency could be raised from 21kHz to 32kHz. Also,
The peak dip of the output sound pressure is ± 3dB, which is about ± 3dB lower than that of the aluminum diaphragm.

EFFECTS OF THE INVENTION As described above, the present invention uses a molded product in which urushiol, which is a phenol derivative, is coated on a plastic film and transferred to pulp, and is used as a diaphragm. It is possible to obtain a speaker that is high and has a large acoustic output, and an excellent speaker having good acoustic characteristics can be realized.

Claims (1)

[Claims] 1. A speaker diaphragm, comprising a molded product obtained by coating a plastic film with urushiol, which is one of the phenol derivatives, and transferring it onto pulp.