JPS57118496

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DESCRIPTION JPS57118496
Detailed description of lIs (no change in the contents), description 1, title of invention
Moving coil fist loudspeaker-
DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a moving coil
loudspeaker. A moving coil loudspeaker has a coiled coil carried on a winding mounted on the
cone or diaphragm of the loudspeaker. The ls coil is suspended within the flux gap between the
pole pieces of the permanent magnet and vibrates in the flux gear, in response to an acoustic
signal applied to the ls coil, to drive the cone or diaphragm. . The frequency response of the
moving coil loudspeaker-in particular the response at low frequencies (bass responsiveness), is
the amount of displacement of the force acting on the chair coil and the chair coil from its rest
position Adverse effects are caused by the non-linearity of the relationship between Such nonlinearities, for example, cause the cone or diaphragm to compress the air in the magnet enclosure
as it travels into the flux gap, thereby causing displacement of the coil. It is caused by K to create
a resisting force. Likewise, the displacement of the sheath coil is again resisted by the fact that
the sheath e coil moves outward from its air gap K and thus the air trapped under the diaphragm
or cone is lean. These phenomena, coupled with the non-linearity in the suspension of the coil
and diaphragm or cone ideally operate on the required linear coil displacement characteristics. A
known method of compensating for the above-mentioned non-linearity is to provide an additional
coil on the winding type to which the chair coil is attached, and to supply a DC signal to this
additional coil (Hi-Fi Two different noises (MIFIN @ Wll), page 63 (in Japanese) (in Japanese),
Chis, Daisy (H, Llpaahuti)) · DC current flowing in the additional coil is one loudspeaker on the
winding form-air in the enclosure Force can be generated to compensate for the reaction force
resulting from the compression of. An additional coil of earth for the winding to exert pushing
force (pulllngfore) and pulling force (pulllngfore) to compensate the reaction force resulting from
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the large displacement of the chair coil Can be provided. A problem with such known
arrangements using self-flowing applied coils is that the coils generate heat in addition to the
heat generated in the use of the loudspeaker for loudspeakers, causing heat dissipation problems.
It is. Furthermore, each additional fill must be accurately positioned for optimal effect, which
necessarily increases the cost of the loudspeaker.
The object of the present invention is to provide a moving coil loudspeaker in which the
compensation of the non-linearity is achieved without resorting to the use of a direct current
applied addition coil. It is known, for example, from the patent FR 2 296 985 to provide a
moving coil loudspeaker in the form in which a "negative feedback" compensation signal is
superimposed on the sound signal applied to the coil. ing. This compensation signal is output
from the electro-optical sensing means, which is at one point to compensate for distortion, in
relation to body rest position i1 in the magnetic field of the loudspeaker magnet, but in response
to the position of the antenna. Such negative feedback compensation reduces distortion in coil
responsiveness but does not compensate for the non-linearity that results from the compression
of air in the magnet enclosure. The present invention is directed to the non-linearity in the
loudspeaker one response resulting from the air compression phenomenon by using as a positive
feedback signal the compensation signal generated from the lis coil position sensing means to be
superimposed on the lis coil signal. Provides a simple solution to the problem of compensating
for. The positive feedback speech signal produces a force on the chair coil that cancels out the
force that results from the compression phenomena of the one cone or sleeve and from the nonlinearity of the coil suspension. A suitable EndPage: 2 sensing means may be used to sense the
movement of the chair coil. In the preferred embodiment, the sensing means is light-optical and
comprises a light source attached to the central pole piece of the cornerstone of the light% Ltx
emitter and the loudspeaker. The coil former has a diffusely reflecting inner surface, the
reflection characteristic of which changes in the direction of displacement of the coil to produce
the desired compensation signal. The advantage of the photoelectric detection device of the
invention lies in its substantial simplicity. This is because expensive and accurate optical means
are not required in the context of light sources or inspection gains. In one embodiment of the
present invention, in the chair coil type, an f-turn of the non-reflective area extending
circumferentially with respect to the reflective area as an edge or non-linear function of the
distance in the displacement direction of the coil It is provided. The compensation signal may be
zero at the rest position of the coil, in contrast to a loudspeaker in which a DC applied additional
coil is employed, however, by including a DC component in the compensation signal in response
to cardiac variations. The actual rest position taken by the chair coil may be compensated. One
embodiment of the present invention will be described with reference to the lower drawing.
FIG. 1 shows the coaxial direction I / C 11! In the convoluted space @z between the concentric
pole pieces 4.5 of the permanent magnet (not shown). ! Fig. 4 shows the substantial components
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of a moving coil loudspeaker with a vibrating diaphragm or cone J carrying a hanging tubular
form. The former 2 is located in the magnetic flux of the air @ S but carries the chair coil 6 so
that when K a tone change signal is supplied to the coil 6; Vibration occurs at 1. For example, to
compensate for non-linearity in the loudspeaker response, in particular the bass response, which
originates from the compression force resulting from the displacement of the loudspeaker cone 1
and the lean blade. The positive feedback compensation signal is superimposed on the acoustic
signal to be Compensation signal is empty @! It depends on the position of the chair coil with
respect to the rest position in l. In the embodiment shown in FIG. 1, the compensation signal is
obtained by directly sensing the position of the chair coil 6 using optical means. An optical
exchanger 7 is mounted on the central pole piece 4. The converter 1 comprises a light source, for
example a phototransistor 8 superimposed on a light emitting diode (llght mlttlngjlod) 9. The
light emitting diode 9 directs the light onto the inner surface of the coil former 2. This inner
surface is diffuse (reflecting to Klf! i! It's supposed to be treated or coached stone. The light
reflected from the former 2 is detected by the phototransistor 8 as shown in FIG. The output
signal of the phototransistor 8 is proportional to the intensity of the light reflected from the inner
surface of the former 2, and the intensity of this light is such that the former 2 projects beyond
the end face of the pole piece 4 Proportional to the amount. That is, the output signal of the
phototransistor 8 depends on the amount of displacement of the coil 6 from its rest position, and
becomes larger as the displacement 1 of the coil becomes larger. ? In the embodiment shown in
FIG. 1, the inner surface of the former 2 is uniformly diffusely reflective and the light emitting
diode 9 emits a broad beam. In such a state, the output signal of the phototransistor 8 depends
substantially linearly on the displacement iiK of the coil winding type 2. If the light emission
characteristics of the light emitting diode 9 and the reflection characteristics of the inner surface
of the winding form 2 are selected as K, the output signal of the transistor 8 and? It is possible to
determine the relationship between the displacement of the chair-coil 6 and the displacement.
Other embodiments of the invention are shown in FIGS. 2, 3 and 41 MIK, where the same
reference numerals are used for the same or corresponding elements as in the embodiment
shown in FIG. In FIG. 2, the inner surface of the coil former 2 is provided with a non-linear
pattern of reflective area I0 and non-reflective area 11 and the light source 9 is a fan beam, ie,
the longitudinal length of the vibration of the coil 6. It emits a beam that is narrowed in direction.
In this configuration, the area of the light reflecting surface exposed to the light beam from the
EndPage: 3 light source or light emitting diode 9 is non-edgewise dependent on the displacement
lid from its resting position of the coiled form 2- . In the embodiment shown in FIG. 3, 11 in the
coil former 2a! A non-reflecting area 12 is provided on the opposite end of the reflective surface
area 10 on the surface of the first surface 10 to limit the maximum displacement of the die coil 6.
Thus, in the rest position shown in FIG. 3, the beam emitted by the light emitting diode 9 will lie
symmetrically between the two non-reflecting regions 12. In this configuration, the
phototransistor 80 field force signal is substantially linearly dependent on the displacement of
the die coil 6 to the maximum allowable amplitude of vibration of the die coil 6. In the
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embodiment shown in FIG. 4, the reflected light □ surface area JOFi of the die coil 2 is sloped
linearly in the circumferential direction between the two end areas of the surface area and
emitted by the light emitting diode 9 The light beam to be emitted is one fan-shaped as in the
embodiment of FIG. In this configuration, the area of the reflective surface 10 presented to the
light beam emitted by the emitting diode 9 depends linearly on the displacement of the chair coil
6 from its rest position. The output of the phototransistor 8 is linearly increased by W when the
die 6 is displaced into the air gap 3, and linearly when the coil 6 is displaced outward from the
air gap 3. Decrease. In order to obtain the desired light emission from the light emitting diode 9,
a lens may be provided in connection with the light emitting diode 9 according to whether a thin
lead beam, m-shaped beam or diffuse radiation is required. Leah. The first 5V is 1 field shown to
obtain the desired compensation signal l! Fig. 3 schematically illustrates an electrical signal
processing circuit used in connection with the phototransistor 8 in an embodiment. The signal
processing circuit includes an operational amplifier 14 to which the output of the phototransistor
8 is supplied, and a second operational amplifier 15 whose output of the dance field rfir 114 is
supplied as a positive NIR signal together with a sound signal. There is.
The output of the operational amplifier 15 includes a tone signal and a positive feedback
compensation signal superimposed thereon, and is supplied to the die coil 6. The amplitude of
the compensation signal with respect to the sound I #, signal can be predetermined by presetting
the gain of the operational amplifier 14 and by adjusting the dimming of the output of the
operational amplifier 14. The body stop position a of the die coil 6 may be adjusted or
compensated by adjusting the direct current (DC) level supplied to the phototransistor 8. It will
be appreciated that the sensing of the displacement lid of the voice coil can be performed by
detecting the position of any component of the die coil assembly or the position of the form 2
moving with the Fi & chair coil. is there. In an optical system for die coil position detection, the
light source used may be, for example, an incandescent lamp, a light emitting diode, a solid state
laser, a beta ray, a neon bulb or a suitable form such as mK with photoelectric effect. Good. The
light receiving device shown as a phototransistor in FIGS. 1 to 4 may have other forms, for
example, a photodiode, selenium sulfide) + Jg, photoconductive light-dependent resistance or
liquid crystal V. Any photoelectric converter capable of converting an iK dependent electrical
output signal of incident light may be used. 4) is a schematic axial sectional view of one
embodiment of the moving coil loudspeaker according to the present invention, and FIGS. 2 to 4
are other embodiments, respectively. 1 is an axial cross-sectional view similar to FIG. 1, a
schematic diagram of a circuit for generating a compensation signal in a loudspeaker according
to the invention, kJ 251k. l ・ ・ ・ cone, 2 ・ ・ ・ winding type, 3 ・ ・ ・ air gear , 4.5 @ rod
piece, 6 ... voice coil, 7 ... converter, 8 ... phototransistor, 9 ... light emitting diode. EndPage: 4 to 5
Showa Date Patent Patenter Harukaden Shimada 1, Display of the case Japanese Patent
Application No. 56-139636 2, Title of the Invention 2, Title of the Invention Moving Coil
Loudspeaker-3, Person who makes correction Relationship with the case Patent applicant The
Rank Organization Limited 4, agent address Toranomon 1-chome Tokomon Minato-ku, Tokyo No.
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5 No. 17 Mori Building 〒 105 Telephone 03 (502) 3181 (dai 11) Name (5B47) Patent Attorney
Takehiko Suzue 5, Date of correction instruction January 2, 2007 L 6; Target statement 7 of
correction Target specification 7 of correction Details of the specification as detailed in the
attached sheet (Content 4-no change) EndPage:
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