JPH05227590A - Speaker with glass diaphragm - Google Patents

Abstract

PURPOSE:To improve the sound quality of a speaker by using the glass board of thickness with a specified limit as a diaphragm in a moving coil type dynamic loudspeaker. CONSTITUTION:The glass board of 0.2-20mum thickness is used as the diaphragm 1, which is fixed to a wooden enclosure 10 at the four places of above/below and right/left with bolts and nuts 11 by way of vibration absorbing materials 9. There is space surrounded by a sound absorbing material 8 between the diaphragm 1 and the enclosure 10. The end part of the sound absorbing material 8 is in contact with the diaphragm 1 so as to limit the vibration of the peripheral part of the diaphragm 1 to prevent resonance in a low sound band. An acoustic signal provided from an amplifier is transmitted from a terminal 7 to a voice coil 2 by way of a lead wire. A speaker main body is fixed to a supporting table. The speaker produced like this can cover almost all of an audible band, has high sound pressure even in a low sound band, shows satisfactry directivity and generates a natural and well-spreading sound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hi-fi speaker using a specific diaphragm.

[0002]

2. Description of the Related Art There are various types of speakers, but the most widely used at present is a moving coil type dynamic speaker (hereinafter simply referred to as a speaker).
Is.

Among the speakers, a high-fidelity speaker aiming for high fidelity reproduction has a frequency of 20 Hz to 20 KH.
It is required to exhibit flat frequency characteristics with little distortion in the human audible band over z. A large-diameter diaphragm is required to reproduce low-pitched sound with low distortion and large sound pressure, but the diaphragm used in the past uses the mass of the vibration system (voice coil, diaphragm, damper, edge, etc.). Since it is designed based on the idea that it should be made as small as possible, it is made thin and does not have sufficient bending rigidity. Therefore, if the diameter is increased, split vibration occurs in the high frequency range, and the flatness of the frequency characteristic is lost. This is the reason why multi-way systems are often used as hi-fi speakers. Generally, a vibrating plate material having a high Young's modulus is preferable because the frequency at which split vibration starts is higher. On the other hand, it is desirable for the diaphragm material to satisfy the second requirement that the internal loss be large, but there is a tendency that the material having a higher Young's modulus has a smaller internal loss,
There is no known material that satisfies the above two requirements at the same time and that has good sound quality (natural sound) as a diaphragm.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to find a material having a high Young's modulus, a large internal loss and a good natural sound, and using it as a diaphragm to improve the sound quality of a speaker. I am trying.

[0005]

As a result of earnest studies to achieve the above object, the present inventor has found that the glass sheet has a high Young's modulus and at the same time has a large internal loss and a good eigentone. As a material, they have found that it is suitable as a diaphragm material for a speaker, and completed the present invention.

That is, the present invention comprises a speaker using a glass plate having a thickness of 0.2 mm or more and 20 mm or less as a diaphragm.

The material of the glass used in the present invention is not particularly limited. In the present invention, glass is defined as an inorganic amorphous solid suspension exhibiting a glass transition phenomenon. Specifically, for example, borosilicate glass, soda lime glass, potash glass, lead glass, oxide glass such as quartz glass, special hard glass known by trade names such as Pyrex, aluminosilicate glass, borate glass, phosphoric acid Examples thereof include salt glass, aluminate and titanate glasses, fluoride glass, chalcogen glass, and metallic glass. In addition, polycrystalline glass known by trade names such as Pyroceram is also included. In the present invention, one kind of plate selected from the above various glasses or a multi-layered plate made of two or more kinds of glass can be adopted.

The thickness of the glass vibrating plate used in the present invention should be determined in relation to its area and shape. Generally, a thin glass plate is used for a vibrating plate having a small area. A thick glass plate is suitable for a large-area diaphragm. If the thickness is less than 0.2 mm, it is easily damaged and is not preferable. On the other hand, if the thickness exceeds 20 mm, the energy required for driving becomes large and the efficiency is remarkably lowered, so that the sound pressure cannot be sufficiently increased at the output of a normal amplifier, which is not preferable. The thickness does not have to be uniform, and consciously set protrusions with a width within 20 mm and a thickness exceeding 20 mm, and non-uniform thickness within an arbitrary width within the above range are allowed. ..

The shape of the glass vibrating plate used in the present invention is not particularly limited, and it may be a flat surface, a flat surface including a partial curved surface, a curved surface such as a cone shape or a dome shape. May be. Further, the outer periphery of the diaphragm is allowed to have a rectangular shape, a square shape, a circular shape, an elliptical shape, a triangular shape, a pentagonal or higher polygonal shape, and any other shape.

The glass vibrating plate used in the present invention is coated with various substances for various purposes, or a film-like or sheet-like substance is adhered or adhered to the whole surface of the vibrating plate or A part of it can be coated. Further, a multilayer glass plate in which a film-shaped or sheet-shaped substance is inserted between two or more glass plates can be used as the vibration plate. The purpose of such coating or insertion is, for example, prevention of breakage of glass or prevention of scattering at the time of breakage. Further, as another purpose, there is an improvement in sound quality by increasing internal loss and an improvement in appearance by coloring.

[0011]

The vibrating plate used in the present invention does not produce sound by piston movement like the vibrating plate used in a normal cone speaker, but forced elastic vibration of the plate whose periphery is substantially fixed. To send out sound waves.
In the speaker configured as described above, the density of the glass plate is high and the glass plate is thick, so that the mass of the vibration system inevitably increases. Generally, as the mass of the vibration system increases, the efficiency decreases if other conditions are constant. However, even if the mass is large, it is possible to suppress the decrease in efficiency by taking measures such as increasing the magnetic flux density of the magnetic circuit, winding as many voice coils as possible in the magnetic gap, and increasing the diaphragm area. In addition, the recent output of amplifiers has increased, and even if the efficiency drops, it does not cause a big problem.

When glass having a sufficient thickness is used as the diaphragm, the damper used in a usual cone type speaker may be unnecessary because of its high strength.
Further, even if the mass is increased by winding a thick and long metal wire as a voice coil in order to improve efficiency, it can be easily fixed and supported on the diaphragm together with the bobbin. Furthermore, since the flexural modulus is large, even a large-area diaphragm that exceeds 0.1 m ² and sometimes reaches several m ² can stand on its own without being substantially deformed. For this reason, the method of attaching a diaphragm by making a hole in a part of the baffle, which is generally used in the past, can be applied, and the baffle does not substantially exist, and most of the front surface of the speaker is A design that is a diaphragm is also possible.

The speaker of the present invention can also be incorporated into a multiway system as a unit.

[0014]

EXAMPLE FIG. 1 shows an example of a speaker using the glass diaphragm of the present invention. The present invention is not limited to this embodiment. The diaphragm 1 has a thickness of 2.
A rectangular flat glass plate having a length of 8 mm, a length of 43 cm, and a width of 30 cm was used. The vibrating plate 1 is fixed to the wooden enclosure 10 via the vibration absorbing material 9 at four positions in the upper, lower, left and right by bolts and nuts 11.

At the center of the diaphragm, a strong cylindrical bobbin 3 made of plastic is fixed with an epoxy adhesive. The bobbin has a voice coil 2 with a diameter of 0.32.
An enamel wire having a length of 30 mm and a length of 30 mm is wound and is fixed by an epoxy adhesive. The DC resistance of the voice coil 2 is about 6Ω.

The magnetic circuit is an outer magnet type, and is composed of a ferrite type cylindrical permanent magnet 4, an iron yoke 6 and a pole 5. A copper short ring is attached to the tip of the pole.

A space surrounded by the sound absorbing material 8 having a thickness of 15 mm is provided between the diaphragm 1 and the enclosure 10.
The end of the sound absorbing material 8 is in contact with the diaphragm, which limits the vibration of the peripheral portion of the diaphragm and prevents resonance in the low sound range. The acoustic signal supplied from the amplifier is transmitted from the terminal 7 to the voice coil 2 through the lead wire. The speaker body is fixed to the support 12. The speaker manufactured in this way can cover almost the entire audible range, has a high sound pressure level in the low frequency range, has good directivity, and produces a natural and extended sound that cannot be thought of as a one-way system. Come out.

[0018]

EFFECTS OF THE INVENTION The speaker using the glass diaphragm of the present invention is a high-performance hi-fi speaker capable of covering almost the entire audible band even in a one-way system having only one speaker unit. Can be manufactured. Further, since it is easy to increase the area of the diaphragm, the degree of freedom in designing the sound quality and appearance is increased, and it is possible to meet a wide range of needs.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a speaker using glass as a diaphragm according to an embodiment of the present invention.

[Explanation of symbols]

 1 vibration plate 2 voice coil 3 bobbin 4 permanent magnet 5 pole 6 yoke 7 terminal 8 sound absorbing material 9 vibration absorbing material 10 enclosure 11 bolt and nut 12 support base

Claims (1)

[Claims] 1. A moving coil type dynamic speaker having a thickness of 0.2 mm or more and 20 m as a diaphragm.
A speaker characterized by using a glass plate of m or less.