JPS62115996A - Speaker - Google Patents

Abstract

PURPOSE:To improve a directivity in a high pitched tone area by dividing a voice coil every band and connecting a divided network so as to drive an entire of an oscillator equally with respect to a low pitched tone and drive only a part of the oscillator with respect to a high pitched tone. CONSTITUTION:The voice coil 2 is completely separate to a voice coil 21 for the low pitched tone and a voice coil 22 for the high pitched tone and to the voice coil 21 for the low pitched tone, the low pass filter 10 of the divided network 9 is connected and to the voice coil 22 for the high pitched tone, the high pass filter 11 of the divided network 9 and an attenuator 12 are connected. When a musical signal is impressed, a low pitched tone component flows to the voice coil 21 for the low pitch tone by the low pass filter 10 and substantial ly all of the oscillator 1 [area shown by a symbol (a)] operates as an acoustic wave radiating surface. While the high pitched tone component flows on the voice coil 22 for the high pitched tone by the high pass filter 11 and only the vicinity of a center of the oscillator 1 [area shown by a symbol (b)] operates as the acoustic wave radiating surface. Thereby, all the bands can be reproduced by one oscillator 1 and a thin plannar speaker having a good directivity during reproducing the high pitched tone is obtained.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a thin flat speaker, and in particular to a vibrating body such as a moving plate or a percussion membrane, in which a voice coil is uniformly disposed over the entire surface. This invention relates to a thin flat speaker.

[Background of the invention]

Conventional speakers are so-called "Gum-Zin type speakers."
As described in Japanese Patent Publication No. 35-10420, a voice coil distributed uniformly over the entire surface is attached to a thin film diaphragm, and the voice coil is inserted into a magnetic circuit according to the shape of the voice coil. By placing the camera on the ground, the imaging plate was driven uniformly over the entire surface.

However, while a certain area of the percussion plate is required depending on the lower limit of the reproduction frequency, the directivity deteriorates in the high frequency range because the drive is uniform over the entire surface.

[Purpose of the invention]

The present invention was made in order to eliminate the above-mentioned drawbacks, and its purpose is to provide a thin flat speaker that reproduces the entire frequency range in a single vibrating body and does not deteriorate its directivity even when reproducing high frequencies. There is a particular thing.

[Summary of the invention]

In order to achieve the above object, the present invention is configured such that the entire diaphragm is driven uniformly for low sounds, and only a small area of the diaphragm is driven for high sounds. , is characterized by improved directivity during high-frequency sound reproduction.

[Embodiments of the invention]

The present invention will be described in detail below with reference to the drawings. N
Figure wc1 is a sectional view of an embodiment of the present invention. In the figure, a vibrating body 1 is made of, for example, a film-like or plate-like resin film, and a plurality of and/or multilayer voice coils 2 are formed on one or both sides of the vibrating body 1 by etching a quadrielectric thin film and foil.

The columnar magnets 3 are attached to a yoke plate 4 forming a magnetic circuit at approximately equal intervals and alternately with opposite polarity, and sound wave radiation holes 5 are formed in the yoke plate 4 between each magnet. The frame 6 holds the upper and lower peripheral edges of the vibrating body 1. The periphery of the yoke plate 4 is attached to the frame 6 with the magnets 3 facing each other with the same polarity.

Figure i2 is a wiring diagram of the voice coil and its associated divided network. In this embodiment, the voice coil 2 is completely independent of the bass voice coil 21 and the treble voice coil 22, and the treble voice coil 22 is vibrated. It is formed only near the center of the body 1. The low-pass filter 1 of the dividing network 9 is connected to the bass voice coil 21.
The bypass filter 11 and attenuator 12 of the division network 9 are connected to the treble voice coil 22.

Next, the operation will be explained. When a music signal is applied, the bass component flows through the bass voice coil 21 through the low-pass filter 10, and almost the entirety of the nine-tone transmission body 1 (the region indicated by the symbol A) operates as a sound wave radiation surface.

On the other hand, the high-pitched sound component flows through the high-pitched voice coil 22 by the bypass filter 11, so near the center of the vibrating body 1 (
Only the region (indicated by the symbol) acts as a sound wave emitting surface.

Therefore, the effective vibration area for high frequency signals is smaller than that for low frequency signals, and the directivity during high frequency reproduction is improved compared to when the vibrating body is driven uniformly over the entire band.

FIG. 5 shows another embodiment of the connection diagram between the voice coil and the divided network, and in this embodiment, several voice coils 23 to 26 and the low-pass filter 10 of the divided network 9 are connected in series. All of them are used for low power, of which the voice coil 24.25
The bypass filter 11 of the divided network 9, the attenuator 12, and the impedance adjusting resistor 13 are connected to the voice coils 24 and 25 for use in high-pitched sounds.

Next, the operation of this embodiment will be explained. When a music signal is applied, the bass component flows through all of the voice coils 23, 24, 25, and 26 via the low-pass filter 10, so that the vibrating body 1 is transmitted almost over its entire surface (the area indicated by C).
acts as a sound wave emitting surface.

On the other hand, since the high-frequency sound component flows only through the voice coils 24 and 25 via the bypass filter 11, only the vicinity of the center of the vibrating body 1 (the area indicated by reference numeral 2) operates as a sound wave radiation surface. Therefore, as in the first embodiment, the directivity during high frequency reproduction is improved.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, the entire vibrating body is uniformly driven for low frequencies;
For high-pitched sounds, only a small area of the negative part of the vibrating body is driven, so a single vibrating body can reproduce the entire band, and it is a thin structure with good directivity when reproducing high-pitched sounds. The effect of obtaining a planar loudspeaker is achieved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a thin flat speaker according to the present invention, FIG. 2 is a connection diagram of a voice coil, a dividing network, etc. showing a first embodiment of the present invention, and FIG. 5 is a second embodiment of the present invention. 1... Vibrating body 2. 21-26... Voice coil 5... Column magnet 4... Yoke plate 5.
...Sound wave radiation hole 6...Frame 9...Division network 10...Low pass filter 11...Bypass filter 12...Attenuator 1 Figure 3

Claims (5)

[Claims] (1) In a thin flat speaker equipped with a flat vibrating body with voice coils arranged uniformly over the entire surface, and a magnetic circuit that applies DC magnetic flux across the voice coil, the vibration described above for bass sounds A thin flat speaker characterized in that the voice coil is divided into bands and connected to a divided network so that the entire body is driven uniformly and only a part of the vibrating body is driven for high-pitched sounds. (2) Claim No. 1 (1) characterized in that a low-pitched voice coil and a high-pitched voice coil are provided on a vibrating body.
) Thin planar speaker described in section 2. (3) A part of the bass voice coil is used as a treble voice coil.
The thin flat speaker described in item 1). (4) The thin planar speaker according to claim (1), characterized in that only the central portion of the vibrating body is driven for high-pitched sounds. (5) The thin planar speaker as set forth in claim (1), wherein the divided network comprises a low-pass filter and a high-pass filter.