JPS5369628

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DESCRIPTION JPS5369628
Loudspeaker of the Invention In the case of a flat plate type speaker having a diaphragm square
diaphragm, the length of one side of the diaphragm is set to 1, and an air load mass and a driving
system mass Mv such as a voice coil and a coil bobbin are included. The ratio μ = Mv / Me is
calculated with the moving system equivalent mass as 鵬, and the diameter dl of the voice coil to
drive the diaphragm. Sunuka characterized by having set to d ten (0, 767 + 、, 01) a.
Claims
DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the improvement
of loudspeakers, and in particular to flat-plate loudspeakers. First, in order to facilitate the
understanding of the present invention, general considerations will be described for this type of
flat plate loudspeaker. When using a flat plate as a speaker diaphragm. It is known that, in a
circular 4 ti moving plate, when it is driven by a voice coil of a diameter corresponding to the
diameter of the diaphragm, it is known that specific divided vibration can be suppressed
according to the driving position. The present inventors have confirmed that the divided
vibration tube can be suppressed by driving with a voice coil of the same diameter. And 1 circle
and square and its physical 4? Sex is different. It can be said that the square is more
advantageous if the two are compared. So both directions i! Ｉ１． In the case of the same
diaphragm area, it is possible to make the frequency which is 13 dB at 30 DEG and 110 dB at 60
DEG with respect to the linear axis approximately 13% higher than that of the square shape in
the same diaphragm area. いま。 -As an example, in the case of a 34aljl circular diaphragm, the
above-mentioned frequency is 10kHz, but in the case of a square of the same area, it is 30ss X
30-, so the frequency is 11.3kl (z Can. Furthermore, if the diameter of the voice coil in the
axisymmetric divided vibration is made appropriate and the lowest order mode is removed and
the mode on it is considered, when the diaphragm of the same material is used, the frequency at
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which this mode stands is circular The square is slightly higher than the square, and therefore,
the Bist EndPage: the square is better than the circular in terms of expansion of the vibration
area. The present invention is based on one or more reasons for proposing a flat plate type
speaker having a base plate and a square diaphragm. The purpose of the purpose is to analyze
mainly the relationship between the size of the above-mentioned diaphragm and the diameter of
the voice coil for driving the diaphragm in the speaker of this rice. もってそのｌｌ！ I Improve
the quality with all things improved. The configuration of a speaker to which the present
invention can be applied will be described below. FIG. 1 and FIG. 2 are a top view like a route
which shows the example, and its principal part longitudinal side view. In the figure, (1) shows a
square top plate, and (2) shows a square opening provided at the center of the plate, and an
aluminum skin is deposited on both sides of the alumino-two-cam plate facing the opening. A flat
diaphragm (3) (composite plate) is disposed via an edge (4), and a bobbin (61) on which a voice
coil (5) is wound is attached to the lower surface thereof.
(7) is a frame provided on the lower side of the upper tooth plate (1). (8) Magnet? 191 U ball
member 11 (l is a plate for forming a magnetic gap with the central projection of this ball
member, al) indicates a damper, and these members are covered with a circular cover (134c)
However, the structure itself is not particularly novel, and the gist of the present invention is the
size of the diaphragm of this type of flat plate type speaker by the analysis as described below
and the experiment based on the analysis. And, the diameter of the driving voice coil is properly
set, and the final conclusion is that the frequency custom-design of the speaker is improved.
Therefore, if the optimal driving position of the square diaphragm is 1 in the case of a free
square plate and the length of one side is a, (0, 2) and (2, 0) are degenerated in the lowest mode
of axisymmetric division vibration Because it is a thing, the shape of the clause is a circle. The
diameter of this nodal circle is equal to 0.767a. Therefore, although the (0, 2 + 2.0) mode
described above should be suppressed if driven by a voice coil of this diameter, the mass of the
voice coil is actually added, so the position of the nodal circle moves. The amount of movement is
related to the ratio of the combined mass of the drive system, that is, the voice coil, coil bobbin,
and other mass to the total vibration system mass including the air load mass, and the node circle
when μ is zero, The diameter d of is 0.767 g, but as μ becomes large, d also increases. If this is
expressed in an approximate expression, d + (0,767 + 0.09 μ) a-m **-e (1) That is, if driven by a
voice coil having a diameter represented by this expression, the lowest-order divided vibration of
axisymmetric is If it is suppressed and therefore the loss in the diaphragm is small, this drive
position must be made quite accurate, but in practice the loss of the edge etc. will be added, so a
margin of about ± 5% with respect to d determined by the above equation There is. Within this
range, almost no disturbance occurs in frequency% injection. Thus, according to the present
invention, a flat plate type loudspeaker having a wide piston taking area and a good% note can be
constructed by satisfying the condition of the above equation (1). Next, with reference to FIG. 3,
experimental results will be briefly described for each frequency characteristic when the
diameter of the voice coil is changed. However, type 1 dimensions and weight of the shooting
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plate are as follows. Skin 30μ aluminum alloy core cell size / 16 aluminum honeycomb 4
diaphragm size 46x46x4 'diaphragm weight 0.9gr Curve IIA voice coil diameter 38': drive system
mass 0.43gr (μ = 0.249) Optimal voice on calculation Coil diameter 39.6 j 'curve ll11 B voice
coil diameter 40 tick drive system mass 0.45 gr (μ = 0.260) calculated optimum voice coil
diameter 39.81 "curve 1i IC voice coil diameter 42 J11: drive system mass 0.47 gr According to
(μ = 0.272) calculated optimal voice coil diameter 40.0j ', fO, 2 + 2.0 is the frequency at which
the (0, 2 + 2.0) mode is present, and the shape of B is almost optimal voice At the coil position,
the C (0, 2 + 2.0) mode is suppressed.
On the other hand, the state of A! 1 is that the voice coil diameter is smaller than the optimum
value (0, 2 + 2.0) The effect of the mode appears in the order of valley-mountain on EndPage: 2
frequency custom order and also. Since the state of C is opposite to that of the human being and
the voice coil diameter is larger than the optimum value, the influence of the (0, 2 + 2.0) mode is
also covered in the order of mountain and valley. As described above, the effects that can be
exerted by the present invention are already apparent, and it can be highly appreciated that the
characteristics of this type of speaker can be significantly improved.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are a plan view plan view showing a
flat plate type loudspeaker to which the present invention can be applied and a longitudinal
sectional side view of the main part thereof, and FIG. 3 shows each when voice coil diameter is
changed. It is a curve figure which shows a characteristic. (1) is a top plate, (21 is an opening
thereof, (3) is a diaphragm, (5) is a voice coil, (61 is a bobbin, (8) is a magnet. (9) is a ball
member, and is a plate. Patent assignee Sony Corporation Attorney Docket ・ In Fig. 2 = =: 第 3 vj
Aj 1%, IIL (Hz)-◆ EndPage: ３
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