JPS5915399

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DESCRIPTION JPS5915399
[0001]
The present invention relates to a vibration detection device, and more particularly to a vibration
detection device in a microphone or the like that detects pneumatic vibration. Conventionally, in
the case of -ficrophone, an electrodynamic type utilizing the generation of electric force and force
at both ends of the conductor by the IL magnetic induction action when the conductor I + '-put in
the magnetic field vibrates by the sound wave There is a microphone, or an electrostatic type
microphone of a system in which a condenser is formed by a diaphragm and a back electrode,
and the change of the electric customer's "" due to the vibration of the diaphragm is converted to
an electric signal). Since the electromotive force of the electrokinetic microbon is proportional to
the velocity amplitude of the conductor, the frequency response to constant amplitude excitation
has a rising characteristic of 6 d 1310 ct, and there is a disadvantage that equalization of -6 dl 17
bcl is required. -Since the EMF of the 'ilf-type' microphone is proportional to the amplitude, the
frequency characteristic is flat, but a high input impedance preamplifier is required to extract the
change in capacitance as a change in potential difference. There is a drawback that the
configuration of the microphone is complicated. The present invention has been made in view of
the above-described problems, and an object of the present invention is to provide a vibration
detection device that has good frequency characteristics and requires less peripheral device
lights. In the present invention, in order to achieve the above object, the magnetic field and the
magnetic field generating means are arranged to act on the generated magnetic field force sensor
together with the magnetic flux, and at least the magnetic sensor and the magnetic field
generating means We adopt composition to make one side vibrate in response to air vibration.
Hereinafter, the present invention will be described in detail based on the embodiments shown in
the drawings. FIG. 1 shows the operation principle of a magnetoresistance effect element as an
example of a magnetic sensor used in the present invention. In general, the magnetoresistance
effect element 11 is formed using a ferromagnetic phase such as Ni--Fe, and when a signal
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magnetic field 13 is applied while flowing a current through the magnetoresistance element 11,
the demagnetizing field 14 has an angle θ within the magnetoresistance element 11. It occurs
with a slope of At this time, when the minimum resistance value of the magnetoresistive element
11 is 1 (.0, and the maximum resistance change amount is ΔR), the resistance value R7 of the
magnetoresistive element 11 is expressed by the following equation. 11, = Ro + ΔR, cos 2 θ, ...
(1) FIG. 2 shows an example of the relationship between the applied magnetic field of this
magnetoresistive element and the resistance value of the element r. Here, the ordinate represents
the resistance value, and the abscissa represents the strength of the magnetic field. As can be
seen from the figure, in order to change the resistance value to the straight line 11 勺 with
respect to the applied magnetic field, it is necessary to change the magnetic field in the region
indicated by reference numeral 1 or 11. In the case of the present invention, area 1.
Although either of II is the same, it is needless to say that the phase of the detection signal is
reversed in the regions 1 and II. Next, FIG. 3 shows the basic configuration of the vibration
detecting device of the present invention. In the figure, load resistances 35 and 11'1 flow power
supply 34 are connected to the magnetoresistance effect element 31 as (the above-mentioned
magnetic-hin-I)-, and output terminals 32 are provided at both ends of the load resistance 35. It
is done. For example, a magnetic field is applied to the magnetoresistance effect element 31 by a
(D-shaped magnet 33 as a magnetic field generating means such as a permanent magnet or an
electromagnet. In the configuration of Jl, when the magnet 33 still causes the magnetic sensor 31
to oscillate in the direction of the arrow 36 in FIG. 3, the output terminals 32 at both ends of the
load resistor 35 are magnetoresistance effect elements corresponding to changes in the magnetic
field. The change in resistance value 31 can detect a voltage change corresponding to the
vibration. A simple DC power supply and load resistor that combines a complex high input
impedance preamplifier with a complex high input impedance preamplifier to replace the
capacitance change with a voltage change such as that in vibration detection in a static′′F1
microphone in the above configuration. It is possible to easily carry out conversion of vibration /
electric signal. Next, FIG. 4 and FIG. 5 show an example in which the above-mentioned vibration
detection device is applied to one 1-k-one-phone. In FIG. 4, the magnetoresistive effect element
42 is coupled to a diaphragm 41 that vibrates in response to the sound wave (air vibration) 44.
As the magnetoresistive element 42 vibrates in the magnetic field of the magnet 43 in response
to the sound wave, the resistance value of the magnetoresistive element 42 fluctuates as
described above. If a circuit similar to that shown in FIG. 3 is connected to this
magnetoresistance effect element 42, an electric signal corresponding to the sound wave 44 can
be taken out. At this time, the change region of the magnetic field of the magnet 43 is a linear
region 1 of FIG. If it is set to II, the change of the electrical signal obtained as described above
with respect to the sound wave 44 can be kept linear. The configuration of FIG. 5 is that the
diaphragm 41 of FIG. 4 is coupled not to the magnetic resistance element 1 but to the magnet 43
and not to the magnetic effect element 42. Also in this case, the sound wave 44 of the magnet 43
and the magnetoresistance effect element 42. In order to obtain the relative motion
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corresponding to /, the same effect as the embodiment of FIG. 1 can be obtained, and another
embodiment is shown in 3 ° and 6 (a), (1)). In the embodiment of FIGS. 6 (a) and 6 (b), the
magnet as the magnetic field generating means is configured using the magnetic thin film 61 (7,
this one-linear thin film 61 also functions as the diaphragm It is a thing. As shown in the side
view of FIG. 6 (a), the magnetic thin film 61 is magnetized at an appropriate period, and it is seen
in the front view of FIG. 6 (1) at the same period as this photosensitive pattern. Thus, the
magnetoresistive effect elements 62 are disposed apart from each other, and their respective
terminals are connected in series.
This causes each magnetic resistance. The effect element 62 is exposed to the leaked magnetic
field 63 of the magnetic thin film 61. When the magnetic thin film 61 vibrates at a frequency
corresponding to the sound wave 44 in the above configuration, the leakage magnetic field 63
across the magnetoresistance effect element 62 corresponds to the vibration (changes as shown
in FIG. Since the resistance E1 / 1 of the element 62 changes, if a circuit similar to that of FIG. 3
is connected to the series connection F4 (: l, the magnetoresistance effect element 62), it
corresponds to the sound wave 44 as in FIG. Electrical signals can be taken out. In each of the
following embodiments, the magnetic sensor is not limited to the magnetoresistive effect
element, but it is also possible to use a magnetoelectric conversion element such as a pole IC
having an application [7]. As apparent from the above description, according to the present
invention, the magnetic sensor and the magnetic field generating means are disposed so as to
generate the magnetic field generated by the magnetic sensor, and at least one of the sensor and
the magnetic field generating means Can be provided corresponding to the air-like vibration, so
that it is possible to provide a vibration detection device that has good frequency characteristics
and requires simple peripheral devices.
[0002]
Brief description of the drawings
[0003]
1 to 6 explain the present invention, and FIG. 1 is an explanatory view for explaining the
operation of the magnetoresistance effect element, FIG. 2 is a diagram showing the operation
characteristic of the magnetoresistance effect element, FIG. The figure shows the basics of the
vibration detecting device according to the present invention ('tlt composition of the small 1'
explanatory drawing, Fig. 1 and 5 show the vibration detecting device according to the present
invention!
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FIG. 6C +) shows a different embodiment of FIG. ± (b) is a fl, 11 而 surface and a top view
respectively showing 12 further embodiments 11 of the vibration detecting device according to
the invention. 11.31, 42.62 · · · magnetoresistive effect element f33. Wave 61, magnetic thin film
63, leakage magnetic field Fig. 1 Fig. 6 (a) (b)
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