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BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing a conventional
condenser type microphone, and FIGS. 2a and 2b are sectional views showing the basic
configuration of the condenser type microphone according to the present invention and one of
its mounting structure parts Notch top view, Fig. 3 atb? C is a side view showing another example
of the FET used in FIG. 2 and a partially cutaway cross-sectional view illustrating the mounting
state thereof, and FIG. 4 is a partial cut showing an example of the mounting structure of the FET
according to the present invention It is a notch sectional view. 11 ··· Case · · · · · · · · · · · · · · · · · · · · · ·
· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ring, 15 · · · · · · · · · 16 ...... mounting
structure, 16a ...... periphery, 16b ...... anchoring piece, 16c ...... pedestal, 16d ...... recess (air
Chambers, 16e · · · · · · · · · · · · vent holes, 16f · · · · · · · · · · · · · · · · · · · · guide holes, 16h · · ·-guide
pins, 17 · · · · · fixed Electrodes 18 ······ (for preamplifier, circuit element for impedance
conversion) FET, 18 g ······ Upper electrode, 18 d ······ Drain electrode, 18 B ··· ··· Source electrode,
19 ···································· Vents, 19b− ········ Recesses, 19c, 19d, 19 e · · · · · · · · · · · · · · · · · · · · · ·
The present invention relates to a condenser type microphone, and more particularly to
improvement of the inner microphone thereof. In the condenser type microphone, the circuit
element of the preamplifier ring is used as a microphone main body as part of the
miniaturization trend. A so-called inner microphone is realized so as to be incorporated
organically. FIG. 1 shows one of such inner microphones, which is particularly well known as a
substrate type. It is also 1 '"1" -J ". That is, first, the diaphragm assembly 3 is disposed to face the
sound receiving hole 2 of the case 1. Here, the diaphragm assembly is one in which the
diaphragm 4 is stretched between the fixing ring 5 and the spacer 6. Next, the fixed electrode 10
having the small hole 9 is brought into contact with the sleeve R 6 via the damper f-Be described
later on the damper mount 8 b of the frame 8 having the collar 7 engaged with the case JK. It is
mounted so as to face the diaphragm 4 in close proximity. Further, the air chamber 12 is formed
by closing the other opening of the frame 8 with the printed wiring board 1. A circuit element 13
for constituting a pre-amplifier mounted on the printed wiring board 11 is accommodated in the
air chamber 12. In addition, the horizontal hole Ja + am formed in the corresponding portion of
the case 1 and the frame 8 and the dangling mount sb. When there is Dan 4'-8e, it becomes
unidirectional, and when it does not, it becomes omnidirectional. Also, the air chamber 12 is
required to increase the capacity change by the diaphragm 4, and the compensation volume is
obtained through the small holes 9 and 8d of the fixed electrode 10 and the vacuum mount 8b.
By providing the air chamber 12, the capacity change obtained by removing the suppression
effect on the vibration of the vibration 114 is made large. By the way, the above-mentioned
substrate type inner microphone has succeeded in its own way to miniaturize it, but in other
respects there is much room to be improved in the same way as the previous one. That is, the
recent need is not only to aim at miniaturizing, but it is exclusively pointing to the coexistence
with the improvement of the cost and the seventh aspect. However, the prior art can not meet the
various needs as described above, in particular, since no consideration is given to the
performance, the workability, the price and the like. That is, the conventional one including the
one shown in FIG. 1 simply mounts the diaphragm on the perforated fixed electrode through the
spacer in the attachment structure of the diaphragm and the fixed electrode which is the heart.
Therefore, it has a disadvantage that the effective utilization of the area of the diaphragm and the
fixed electrode, which suffers from the so-called edge effect and the planar drive being inhibited,
is low and the distortion characteristics are poor.
ていた。 And when expensive electrets are used for fixed electrodes, there is a stagnation that
can not effectively use electric charge, and if so-called paris or warpage occurs due to the
presence of a perforated portion, the co-VC effective drive capacity is The defect (the same as in
the case of a conventional fixed electrode) K is also linked, leading to a cost increase due to the
presence of a spacer and an increase in the number of operation steps. There is a problem that
the mounting structure and the lead extraction thereof are complicated and weak. In addition, the
horizontal holes formed to achieve unidirectionality are complicated because they require
positional alignment between the case and the frame, and in this case, a Danno mother is
attached to the lower part of the fixed electrode to have a filter effect. Since it is necessary to
provide through the agent, the flatness of the fixed electrode will be dispersed because the
thickness of the adhesive or sheet, the thickness of the member (usually paper or cloth) =, the
thickness of the fixed electrode A1,. It was easy to bring about the undesirable situation of the
dispersion of sensitivity and the adsorption of the diaphragm. And while such a structure to
obtain unidirectionality is basically required to cancel the sound source of 180 'phase difference,
it is a system replaced with a 90 ° phase difference, so a very good directivity can be obtained.
It was nothing. For this reason, eliminating the above-mentioned drawbacks is an urgent issue
especially for the inner microphone as well as for the condenser microphone in general, and in
the case of the inner microphone, it is strongly desired to exert its function more organically.
Therefore, this invention was made in view of the above points, and in particular, for the purpose
of providing a very storm-like capacitor type microphone that can more efficiently exhibit its
function as an inner microphone. There is. That is, the feature of the present invention is to press
the conical circuit element into the tapered recess of the mounting structure: "; one point, which
makes it possible to eliminate the sound leakage and make the press-in operation easy. It is a
thing. Hereinafter, the basic configuration to which the inch-microphone according to the present
invention is applied will be described in detail with reference to the drawings, that is, in FIG. And
a plurality of sound receiving holes 12 formed at the bottom thereof, and a diaphragm assembly
IJJ3 is disposed on the inner bottom portion of the case 1 to face the sound receiving holes 12. It
will be set up. Here, the diaphragm assembly Lλ is formed by stretching the diaphragm 15 made
of a metal foil such as aluminum in advance under the metal ring 14 which is fitted to the inner
bottom portion of the case 11 to make an electrical contact. Also, the above-mentioned
diaphragm assembly 13 is held in the case 11 in the case 11 without using a sensor and a
predetermined gap f (for example, about 0.1 sn A fixed attachment 17 made of stainless steel
having a plurality of fixed pieces 16b and fixed mounts r6c and the like for facing the fixed
electrode 17 in advance. Here, the fixed piece 16b of the woven structure L "is protruded from
the recessed portion 16d serving as an air chamber as shown in FIG. 2 (b), one of which is shown.
Have an elastic effect, and In this case, it is determined that a total of four are formed at intervals
of 90 degrees, and the fixed electrode 17 is tightly fitted on the pedestal 16e of the fixed piece
16b of the assembly frame using its elastic effect. In this case, the fixed electrode 17 itself does
not have a vent, as in the prior art.
Further, the predetermined gap provided between the fixed electrode 12 and the diaphragm 15
is set by the difference in height between the periphery 116m of the mounting structure and the
pedestal 16c, whereby the predetermined gap is made as in the prior art. It does not use a
speaker to obtain. Furthermore, the mounting structure L1 described above is formed with a vent
hole 16 for obtaining directivity at the bottom of the mounting structure L1 at the bottom and in
communication with the recessed portion 16d, that is, the air chamber. Circuit elements for
forming a pre-amplifier, for example, field effect transistor (FET) for impedance conversion,
recess J6 f for press-fitting and storing 1 g and well-embedded FITl & 's gate press-fitted in the
recess 16 f A guide hole 16g for electrically contacting the contact electrode J8g with the back
surface of the fixed electrode 17 is formed as shown in FIG. Correspondingly, the printed wiring
board 19 in which the vent hole J9a is formed is mounted in the case 1] in a state where the
damper 20 is sandwiched between the mounting structure ↓-(and the bottom portion thereof. In
this case, the printed wiring board 19 is positioned by having the guide pins 16 b protruding
from the bottom of the mounting structure 16 and the four portions 19 b to be mounted on an
iron base. In addition, the drain / fon electrode J8d of the FET 18 thus projected like the back of
the printed wiring board 19: → or so 7M! lIRm is soldered to its turn 19C11 sdt5. After that, as
the inner end of the open end of the XTX is narrowed inward, the contour microphone is
completed with 1-7, in particular, the modified internal microphone is completed, where:-the
open end of the snow The part is in electrical contact with the ground (common) pattern 19 e of
the printed wiring board 19 by being indented / swept as if it were bitten. Thus, the patterns 19c
and 19t1.19e may be used as external lead terminals. The above-described configuration for
obtaining single-directionality by the explanation company is shown, and in the case of obtaining
nondirectionality. The condenser type microphone according to the above-described
configuration can be provided with the diaphragm which is the center portion of the condenser
structure microphone and the above-described configuration. In the fixed electrode mounting
structure, the vibration plate 15 is stretched on the lower side of the ring 14 instead of simply
tracing the vibration on the perforated fixed electrode as in the prior art. The fixed plate 16b and
the base 16eK of the plate structure having the peripheral portion 16a for clamping the installed
diaphragm assembly to the case without using the squeezer The fixed electrode 17 having a
diameter smaller than 15 is fitted to the diaphragm 15 with a predetermined gap O. With this,
first, the fixed electrode 1i1y is made smaller in diameter than the diaphragm 15, that is, fixed
Since the diaphragm 15 is not placed on the electrode 17, only the portion of the entire area of
the diaphragm 15 which can be driven flat as much as possible without using the conventional
edge effect is used. As a result, the effective utilization rate of the diaphragm 15 and the fixed
electrode 11 becomes high, and it becomes possible to improve the distortion characteristics as a
result. In addition, the material cost due to the small area of the fixed electrode 17 In particular,
it is effective when using a elective electret, and only 4 in that case there is nothing to contact the
surface, preventing the reduction of the charge in that part by 0 over -r. Contribute the total
charge to the drive Can be used efficiently, and since the non-porous fixed electrode 17 can be
used, there is no Paris or warpage caused by the presence of the perforated portion as in the
past, and the process of forming grooves is omitted. For example, it is possible to easily
manufacture with the original mold and to improve the conversion efficiency by increasing the
volume k of the portion without holes and further improving the efficiency k.
In particular, this is effective when using electrets and is extremely advantageous because it can
maintain the uniformity of the surface charge, where it can be a non-porous fixing tm in this case
by fixing the fixed electrode 17. This is because the fixing piece 16b is protruded from the inside
of the concave portion Jbd serving as the air chamber, and the air for removing the suppressing
effect on the vibration of the diaphragm 15 even if the fixed 117 itself is not provided with the
vent. This is because the chamber, that is, the recessed portion 16 d is present. The air chamber
as the compensation volume is sufficiently secured by a concave portion having 11 volumes as
illustrated. In other words, it is meaningless to make the volume of the air chamber larger than
necessary, and it is not preferable because it is also a factor to inhibit the dust reduction, and
from this point of view, the one by the recessed portion J15d is rational In addition, since it is not
necessary to use a spacer, it is possible to reduce the number of operation steps as much as the
number of parts. This is advantageous because it eliminates the ineffective capacity generated in
the shear-ser portion, that is, the capacity that does not contribute to the drive of the diaphragm,
leaving only the truly necessary effective capacity. In particular, in the case of an electret fixed
electrode, it is effective because there is no voltage deterioration caused by the spacer contacting
the electret surface. Furthermore, although the fixed electrode 17 is sandwiched by the fixing
pieces 16b which are projected from the inside of the recessed portion 16 of the mounting
structure 16 at its circumferential part, the # fixing piece 16b may also have an elastic effect. ,
111. Since the concave portion 16421 which is required as an air chamber without being fixed
and the needle is secured by being formed so as to project from the inside, it is extremely
convenient in manufacturing and is rationally organic and the fixed electrode is firmly fixed. In
addition, since the air chamber is not formed immediately below the fixed electrode, the air
chamber is not limited by the length of the electrode electrically contacting the back surface of
the fixed electrode. It can be formed arbitrarily, and it becomes possible to improve the
sensitivity. Furthermore, in order to obtain unidirectionality, the condenser microphone
according to the above-described configuration is not provided with lateral holes in the case and
the frame as in the prior art, and in addition with a dan / mother under the fixed electrode.
Between the vertical air vents 16 · · · and the printed wiring board 190 air vents 19 &
corresponding to the vertical air vents 16 · · · provided in the bottom of the 1 g in communication
with the recess 1 g & to be the air chamber It consists of 20 pieces.
As a result, there is no need to form a horizontal hole in the case 11 first, thereby reducing the
processing cost, and there is no need to align with the horizontal hole to be formed in the frame
31 → simple and easy to automate It becomes. In addition, since a sound source with a 180 °
phase difference can be canceled essentially, a better unidirectionality can be obtained, and the
damper 20 is held by the printed wiring board 19 at the bottom of the mounting structure
opening. Since it is provided, it is possible to reduce the cost without the need for an adhesive
and to facilitate automation easily. Also, since this does not affect the flatness of the fixed
electrode in any way as in the prior art, it can be prevented in advance from the undesirable
situation of variations in sensitivity and adsorption of the diaphragm. is there. Also, in this case,
the printed wiring board 19 is mounted on the bottom of the mounting structure L1 in a state
where the printed circuit board 19 is positioned by fitting the guide pin 16b protruding from the
bottom of the mounting structure opening into the recess 19b. 217) When caulking the open
end, it is considered to eliminate the positional deviation and to take a regular position. By this, 4
inch for electrode connection. It is convenient because it is possible to prevent the position 2 of
the notches 19c and 19d from being displaced and block the air hole 16 @ of the mounting
structure 16 in advance. That is, where it would be ensured to obtain good unidirectionality
without variation, the FET lg in the above is embedded so that its main body portion is press-fit in
the recess 161 provided in the bottom of the mounting structure. At the same time, the source
electrode 18g is inserted into the guide hole 76g and electrically contacted to the back surface of
the fixed electrode 17. Therefore, the date electrode 18g of the FET 1B has an elastic effect so as
to be more flexible than the other drain electrode 18d and the source electrode 18S, and is in
elastic contact with the back surface of the fixed electrode 17 desired. That is, without such a
consideration, the electrical contact between the gate electrode 18g and the fixed electrode 17
may not be obtained. Further, since the drain / electrode J8d and the source electrode 113s are
soldered to the printed wiring board 19 and sometimes used as a 5I-.tau. External lead-out
terminal in some cases, it is preferable to be as strong as possible. That is, the FET J & used in
this type of deformed substrate type is required to form the electrode structure in a
distinguishable manner in terms of strength and application, and FIG. 3 responds to such a
demand. This is an example of the FET Jlt, and (a) the figure shows that the dirt electrode igg is
made thinner with respect to the source electrode 18m and the drain electrode 18d or the
material is changed to have flexibility.
Also, in FIG. 6B, by bending the r-t electrode jJg into a waveform, as shown in FIG. 6E, the contact
is made more in contact with the back surface of the fixed electrode 17 and a better contact is
obtained. It is as obtained. Thus, by using the r-t electrode 18g with such consideration, the
contact with the back surface of the fixed electrode 17 can be made simply and favorably, and
the use of welding, soldering, and an adhesive is essential. Since it is not possible to reduce the
number of operation steps, it is possible to reduce cost and yield by 61. In this case, FETI & is
pressed into the recess 16f whose main body is formed in the bottom of the brazed structure 1g.
Because it is embedded as such, in the normal case, the undesirable phenomenon of so-called
sound leakage can be avoided. However, the FETI & is generally in the form of a rectangular
parallelepiped main body, and if there is a variation in dimensional tolerance of the
corresponding recess 161 of the mounting structure opening, sound leakage tends to occur
through the gap. This is more likely to be promoted when the mounting structure port is
manufactured by molding, since the concave portion J6f needs to be given a slight amount of die
for die-cutting. In some cases, it is likely that the FET JJl can not be pressed into the recess 16f,
depending on circumstances. Furthermore, in the case of automation, if the cross-sectional shape
is rectangular, positioning is required at the time of press-fitting, which makes automation
difficult. For this reason, the attachment structure of Frr18 which is easy to press-fit is desired
with 7) A2 'which can prevent that the flatness of the frequency characteristic produced by
sound leakage is disturbed beforehand. FIG. 4 shows the mounting structure of the FET J8
according to the feature of the present invention according to such a request, in which case the
shape of FKTJB itself is formed into a cone (especially cone) fall and the dirt electrode on the
small diameter portion side The source electrode 18s and the drain electrode 18d are disposed
on the side of the large diameter portion 18g. Then, the concave portion 16 of the mounting
structure 16 is also formed in a Chie shape corresponding to the conical FE 71 g. According to
this, it is possible to easily press-in regardless of the respective dimensional tolerances, and the
sound leakage can be completely prevented. One can obtain good jIIIIIL inertia, and positioning
at the time of press-fitting is unnecessary, so it will be extremely easy to automate. Also, mold the
mounting structure holiday! Even in the case of It11, the concave portion J6f is tapered in
advance, which may be advantageous. Therefore, according to the present invention, as described
in detail above, it spread on the lower surface of the fixed electrode and spread like a chisel. In
particular, the function as an inner microphone can be more organically exhibited by forming a
pyramidal circuit element into the recess of the mounting structure having the concave 8 by
press-fitting. It becomes possible to provide a condenser microphone which is extremely good.