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JP2006319626

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2006319626
To widen the reproduction frequency band of a screen speaker system without changing the
structure significantly. A screen speaker system 10 having a screen 12 for projecting an image in
a projector and driving the screen 12 to emit sound from the screen 12 includes a driver 50 for
driving the screen 12 and the screen 12. And at least one or more piezoelectric elements 70 for
reproducing in a frequency band higher than the reproduction frequency band in the driving
body 50. [Selected figure] Figure 11
スクリーンスピーカシステム
[0001]
The present invention relates to a screen speaker system that emits sound from a screen that
projects an image projected from the outside.
[0002]
In recent years, in order to provide a more powerful image, in a home theater system, a screen
for projecting the image is being enlarged, and an accompanying acoustic system is also
required.
In order to meet the demand, in the sound system, a 5.1 channel system capable of obtaining a
more three-dimensional and realistic sound effect than stereo output is adopted. In the case of a
screen speaker system, a signal for center speaker is added to a voice coil disposed at the center
08-05-2019
1
of the screen corresponding to a 5.1 channel system, and signals for left and right channels are
applied to voice coils disposed on the left and right thereof. In addition, sound is emitted from
the front of the screen. As such a type of screen speaker system, for example, one disclosed in
Patent Document 1 is known.
[0003]
JP 2005-64932 A (FIGS. 21 to 23)
[0004]
In the screen speaker system described in Patent Document 1, the screen is held by a housing,
the housing is divided into three areas by a central frame, and a voice coil is disposed on the back
surface of the screen in the divided areas, The screen is driven by arranging a magnetic circuit
for driving the voice coil on the housing side.
[0005]
However, in the screen speaker system described in Patent Document 1, each divided area is
driven by one voice coil.
For this reason, the driving power alone has a disadvantage that the reproduced sound in the
high frequency range in the reproduction frequency band is insufficient.
In order to solve this drawback, side speakers must be used in combination on the left and right
of the screen speaker system in order to compensate for the reproduction of the high range.
[0006]
In addition, when the screen is required to be large and the screen external dimensions are
increased, the side speakers are disposed at a position away from the center of the screen,
resulting in high-pitched sound reproduction in the center of the screen. It can not compensate
enough. Therefore, the central part of the screen has a problem that the reproduction capability
of the high range is insufficient.
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[0007]
The present invention has been made in view of the above problems, and an object of the present
invention is to provide a screen speaker system which is high performance and driven in a wide
reproduction frequency band.
[0008]
In order to solve the above problems, the present invention has a screen that projects an image
with a projector, and drives the screen to emit sound from the screen. A piezoelectric element for
driving the screen, comprising at least one or more piezoelectric elements for reproducing in a
frequency band higher than a reproduction frequency band in the driving body.
[0009]
In addition to the above-described invention, in addition to the above-described invention, the
drive includes a voice coil and a magnetic circuit, and the voice coil and the piezoelectric element
have an input signal shared, and the voice coil The first signal amplified by the second amplifier
is input, and the second signal amplified by the second amplifier different from the first amplifier
is input to the piezoelectric element, and the input side of the piezoelectric element is input. A
filter circuit is provided which passes at least the high frequency side of the frequency band of
the input signal.
[0010]
According to another invention, in addition to the above-mentioned invention, the filter circuit
has a band filter which passes only a predetermined frequency band within the frequency band
of the input signal.
[0011]
Also, in another invention, in addition to the above-mentioned invention, the output of the filter
circuit is connected to the input of the second amplifier.
[0012]
Further, according to another invention, in addition to the above-described inventions, at least
two or more piezoelectric elements are connected in parallel on the output side of the second
amplifier.
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[0013]
According to the present invention, it is possible to provide a screen speaker system which is
high performance and driven in a wide frequency band.
[0014]
Hereinafter, a screen speaker system 10 according to an embodiment of the present invention
will be described based on FIGS. 1 to 13.
FIG. 1 is a perspective view showing a screen speaker system 10 according to an embodiment of
the present invention, and FIG. 2 is a perspective view showing the screen speaker system 10
with the screen 12 removed.
FIG. 3 shows a portion in the vicinity of the driving body 50, where (a) is a cross-sectional view
showing a state in which the driving body 50 is disassembled and (b) is a cross-sectional view
showing a state in which the driving body 50 is assembled. It is.
4 is a perspective view showing the case 14 constituting the screen speaker system 10, and FIG.
5 is a perspective view showing the back plate 15 constituting the case 14 in FIG.
6 is an exploded perspective view showing a state in which the back plate 15 is attached to the
frame 16, and FIG. 7 is an enlarged view of a portion shown by arrow E in FIG.
8 is a partial cross-sectional view of a portion cut along the line K-K in FIG. 1, and FIG. 9 is a
perspective view of the magnetic circuit housing 40 as viewed from above.
FIG. 10 is a view showing the configuration of the drive body 50, where (a) is an exploded
perspective view of the drive body 50, and (b) is a view from the side of the back plate 15 with
the drive body 50 assembled. It is a perspective view at the time of seeing.
FIG. 11 is a cross-sectional view taken along line N-N in FIG. FIG. 12 is a schematic view showing
the positional relationship between the voice coil 52 and the piezoelectric element 70 used in the
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screen speaker 10. FIG. 13 is a diagram showing the configuration of the drive circuit 74 of the
screen speaker system 10. As shown in FIG. FIG. 14 is a diagram showing frequency
characteristics of the screen speaker system 10, where (a) is a diagram showing the case where
the screen speaker system 10 is driven by only the driver 50, and (b) is a screen speaker system.
10 is a view showing a case where only the piezoelectric element 70 drives 10, and (c) is a view
showing a case where the screen speaker system 10 is driven using a drive circuit 74. In
addition, in FIG.1, FIG.4, FIG.5, one end side points out the left diagonal upper direction, and the
other end side points out the diagonally lower right. Further, in FIG. 2 and FIG. 3, one end side
indicates the left side, and the other end side indicates the right side. Further, in the present
embodiment, a driver 50 having a magnetic circuit 30 and a voice coil 52 is adopted as a driver
for driving the screen, and a housing for holding the magnetic circuit 30 is used. The magnetic
circuit housing 40 is adopted.
[0015]
The screen speaker system 10 is a direct drive screen speaker system, and as shown in FIGS. 1, 2,
3 and 12, a screen 12 for projecting an image from the outside, a housing 14 for holding the
screen 12, and A driving body 50 for vibrating the screen 12, a magnetic circuit 30 constituting
the driving body 50, a magnetic circuit housing 40 for holding the magnetic circuit 30, and a
piezoelectric for vibrating the screen 12 in a high frequency band in comparison with the driving
body 50. The element 70 is mainly composed of:
[0016]
As shown in FIG. 4, the housing 14 is composed of three back plates 15 and a frame 16
surrounding the three back plates 15.
The back plate 15 is a plate-like member having a rectangular shape, and is made of plywood
having a thickness of 4 mm, with Lauan as a core material, on which the china is superimposed,
and on the surface, aluminum having a thickness of 1 mm. The board is glued. Therefore, the
back plate 15 is a plywood of 5 mm in thickness which has an aluminum plate on the surface.
Further, the frame 16 is composed of a side frame 17 which is a frame member having a
rectangular shape, and a middle cross 18 arranged inside the side frame 17 along the short
direction of the rectangle. The side frame 17 and the middle cross 18 are made of plywood in
which three pieces of ash material are cut out and laminated.
[0017]
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As shown in FIG. 4, the side frame 17 is disposed above the outer edge of the back plate 15, and
includes two longitudinal side frames 17 a and 17 a constituting the longitudinal direction of the
side frame 17, and the side frame 17. It is comprised from two short side frames 17b and 17b
which comprise the short direction of. In the drawing, the longitudinal side frame 17a and the
short side frame 17b are shown by 17 (17a) and 17 (17b) respectively. As described above, the
middle crosspieces 18 are arranged inside the side frame 17 in the lateral direction, and divide
the inside area of the side frame 17 into three at equal intervals along the longitudinal direction.
Further, the end faces of both ends of the middle cross piece 18 are both bonded to the
longitudinal side frame 17a by an adhesive and play a role of improving the strength of the
frame 16 (see FIG. 4).
[0018]
Further, the frame 16 is formed by attaching the center cross 18 to the inside of the side frame
17, and thereafter, as shown in FIG. 6, three back plates 15 from the back side of the frame 16
are formed by the center cross. It arrange | positions respectively in the form which block |
closes the back side of three area | regions divided | segmented. The portion indicated by arrow
E in FIG. 6 indicates the cross-sectional shape of the side frame 17. As shown in FIG. 7, on the
front side of the side frame 17 on the side where the screen 12 is attached to the housing 14,
grooving is performed to a predetermined position on the way from the inner peripheral surface
17 c to the outer peripheral surface 17 d of the side frame 17. The provided step 17e is formed
along the longitudinal direction. The back side of the side frame 17 to which the back plate 15 is
attached is a flat surface and is not particularly processed. Further, at a predetermined position
on the inner side of the longitudinal side frame 17a, a groove portion (not shown) for the middle
bar 18 to be fitted in is formed.
[0019]
The screen 12 is attached so as to be fitted in a step 17 e provided on the side frame 17. Further,
the back plate 15 is attached by screwing to a plurality of locations of the frame 16. As described
above, when the screen 12 and the back plate 15 are attached to the frame 16, the cross section
of the outer edge portion of the screen speaker system 10 is as shown in FIG.
[0020]
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Furthermore, in the center of each back plate 15, an insertion hole 15m for inserting a magnetic
circuit 30 described later is provided in the screen speaker system 10 from the back side of the
screen speaker system 10 (see FIG. 5). ). In addition, mounting holes 15r (see FIG. 3) for fixing
the magnetic circuit housing 40 for holding the magnetic circuit 30 to the back plate 15 are
provided on the outer peripheral edge of the insertion hole 15m at an interval of 45 degrees
along the circumferential direction. There are eight provided. Further, in the vicinity of the lower
end face 15p in each back plate 15, two terminal holes 15q are provided so as to be symmetrical
with respect to a center line passing through the center of the insertion hole 15m and going in
the lateral direction. (See Figure 5). The terminal hole 15 q is a hole for arranging an input
terminal substrate (not shown) for transmitting a voltage to the voice coil 52 and the
piezoelectric element 70. That is, two terminal holes 15 q are provided on each back surface 15.
[0021]
In the present embodiment, as shown in FIG. 2, a magnetic circuit housing 40 for holding the
magnetic circuit 30 in each of the divided portions 14 a divided into three equal volumes by two
hollows 18 in the housing 14. Is arranged.
[0022]
The magnetic circuit 30 is comprised from the holder 31 and the magnet 32 used as magnetism
generation means, as shown to Fig.3 (a).
The holder 31 includes a mounting holder 31a and a holding holder 31b. In the drawing, the
placement holder 31a and the holding holder 31b are shown by 31 (31a) and 31 (31b),
respectively. As shown in FIG. 3 (a), the placement holder 31a is formed so that a cylindrical
portion 31d having a cylindrical shape protrudes downward in FIG. 3 (a) from the center of the
bottom 31c having a bottom with a bottom. . Further, the holding holder 31b has a shape having
a circular hole 31e of a size that allows insertion of the cylindrical portion 31d at the center of
the disc. Then, the ring-shaped magnet 32 is inserted through the cylindrical portion 31 d, and
the holding holder 31 b is inserted through the cylindrical portion 31 d of the mounting holder
31 from below to engage the magnet 32 with the bottom portion 31 c of the mounting holder 31
a. Stop it. In addition, a gap 30d is formed between the inner peripheral surface of the circular
hole 31e formed in the holding holder 31b and the outer peripheral surface of the cylindrical
portion 31d. The magnetic circuit 30 is formed as described above.
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[0023]
The magnetic circuit housing 40 is a holder for arranging the magnetic circuit 30 therein and
holding the magnetic circuit 30 with respect to the housing 14. Further, the magnetic circuit
housing 40 is disposed above the insertion hole 15m provided in the back plate 15, and screwed
from the back side of the back plate 15 through the mounting hole 15r to the frame 16 It is
fixed. Since one magnetic circuit housing 40 is disposed for each back plate 15, a total of three
magnetic circuit housings 40 are disposed inside the housing 14. The outer shape of the
magnetic circuit housing 40 is, as shown in FIG. 9, a regular octahedron whose front is a regular
octagon. In FIG. 9, assuming that the upper surface is the upper surface 40a and the lower
surface is the lower surface 40b, a total of eight protrusions 40c are separated by grooves at the
outer edge of the upper surface 40a to correspond to the sides of the regular octagon. It is
provided. A tapered portion 40d is formed on the inner side of each projecting portion 40c so as
to form a circumference centered on the central axis M-M of the magnetic circuit housing 40.
[0024]
Further, as shown in FIG. 3A and FIG. 9, the magnetic circuit housing 40 is provided with a
circular hole 41 centered on the central axis M-M. The circular hole 41 has a diameter smaller
than the small diameter circular hole 41a, a medium diameter circular hole 41b having a larger
diameter than the small diameter circular hole 41a, and a diameter larger than the medium
diameter circular hole 41b in order from the upper surface 40a to the lower surface 40b. And a
large diameter circular hole 41c. The large diameter circular hole 41c is formed substantially
inside the circumferential protrusion 41d, and the outside of the protrusion 41d is scraped off
over the entire circumference. Further, the portion that has been scraped off is a step 41e. The
stepped portion 41e is formed above the boundary surface 41f which is a boundary between the
medium diameter circular hole portion 41b and the large diameter circular hole portion 41c in
FIG. 3A. Further, a portion serving as a boundary between the small diameter circular hole
portion 41a and the medium diameter circular hole portion 41b is a boundary surface 41g. A
taper 41 h is formed over the entire circumference at a corner where the inner peripheral
surface of the small diameter circular hole portion 41 a and the boundary surface 41 g meet.
[0025]
Further, eight screw holes 41 j are formed in the step portion 41 e so as to correspond to the
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mounting holes 15 r provided in the back plate 15. Furthermore, eight screw holes 41k are
provided at intervals of 45 degrees along the circumferential direction on the boundary surface
41f. Each of the screw holes 41k is formed to be shifted by 22.5 degrees along the
circumferential direction with respect to the respective screw holes 41j.
[0026]
Further, as shown in FIG. 9, the magnetic circuit housing 40 has eight outer peripheral surfaces
40f forming an octahedron. Also, the magnetic circuit housing 40 is made of aluminum, and the
distance between the opposing sides of the octagon is 150.8 mm. However, the distance is not
limited to 150.8 mm.
[0027]
As shown in FIG. 12, three voice coils 52 are arranged on the back surface 12 a of the screen 12
so as to correspond to the position of the magnetic circuit housing 40. The voice coil 52
constitutes a part of the driving body 50 for driving the screen 12 and is formed by winding a
coil wire around a coil bobbin 53 of a predetermined size. Further, as shown in FIG. 3, a terminal
flange 55 for fixing the input terminal 54 is attached to the back surface 12 a of the screen 12.
Then, the coil bobbin 53 around which the voice coil 52 is wound is mounted in the recess 55 a
provided in the terminal flange 55. As described above, the voice coil 52 is disposed on the back
surface 12 a of the screen 12. Further, as shown in FIGS. 11 and 12, four piezoelectric elements
70 are disposed at positions corresponding to the vicinity of the four corners of each divided
portion 14 a on the back surface 12 a of the screen 12. That is, in the screen speaker system 10,
a total of 12 piezoelectric elements 70 are arranged in each of the division parts 14a, four each.
[0028]
Further, the input terminal substrate is attached (not shown) to each of the two terminal holes 15
q formed in the back plate 15, and input to the voice coil 52 and the piezoelectric element 70
attached to the back surface 12 a of the screen 12. The lead wire (not shown) for the input signal
of is attached to the surface of the back plate 15. One end of one lead wire (not shown) is
connected to the input terminal 54 of the voice coil 52, and one end of the other lead wire (not
shown) is connected to the input terminal 72 of the piezoelectric element 70. Further, the other
ends of the lead wires (not shown) are connected to respective input terminal substrates (not
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shown).
[0029]
As shown in FIG. 3A, with the magnetic circuit housing 40 disposed in the housing 14 and the
screen 12 attached to the housing 14, as shown in FIG. 3B, the back side of the back plate 15 is
shown. Then, the magnetic circuit 30 is inserted into the circular hole 41 of the magnetic circuit
housing 40 until the corner 31 f of the magnet 32 abuts on the boundary surface 41 g of the
magnetic circuit housing 40. Thus, the voice coil 52 is disposed inside the air gap 30 d formed in
the magnetic circuit 30. Next, in the state where the magnetic circuit 30 is disposed at the
predetermined position as described above, the disk-shaped holding plate 33 having the central
hole for holding the magnetic circuit 30 is shown in FIG. It is fitted into the large diameter
circular hole 41 c of the magnetic circuit housing 40 from above. The holding plate 33 is
provided with eight screw holes 33 a in the circumferential direction so as to correspond to the
screw holes 41 k formed in the magnetic circuit housing 40. Therefore, a screw can be inserted
into the screw hole 33a, and the holding plate 33 can be screwed to the magnetic circuit housing
40 by the screw hole 41k. As described above, as shown in FIG. 3 (b), the magnetic circuit 30 is
housed in the housing 14.
[0030]
Next, a drive system of the screen speaker system 10 will be described.
[0031]
As shown in FIG. 12, in the screen speaker system 10, one voice coil 52 and four piezoelectric
elements 70 in each divided portion 14a, for a total of three voice coils 52 and twelve
piezoelectric elements 70. It is arranged.
The voice coil 52 is driven in a low frequency band in comparison with the piezoelectric element
70 and drives the piezoelectric element 70 in a high frequency band (in the following
description, driving the voice coil 52 drives the driver 50 The meaning of that is also included.).
Thus, the screen speaker system 10 is driven in a wide frequency band by using the voice coil 52
and the piezoelectric element 70 in combination.
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[0032]
In the configuration of the drive circuit 74 of the screen speaker system 10, as shown in FIG. 13,
a signal is output from the common input means 75 for the voice coil 52 and the piezoelectric
element 70, and the voice coil 52 and the piezoelectric element 70 It is connected in parallel to
the means 75. The signal for the voice coil 52 is amplified by the signal amplifier (first amplifier)
76 and then input to the voice coil 52. On the other hand, the signal for the piezoelectric element
70 is input to a filter circuit (band filter) 77 having a high pass filter and a low pass filter, and the
filter circuit 77 sets the signal to a suitable frequency band. Thereafter, the signal output from
the filter circuit 77 is input to the signal amplifier (second amplifier) 78, amplified by the signal
amplifier 78, and input to the piezoelectric element 70. Here, the filter circuit 77 passes a
relatively high frequency band among the frequency bands of the original signal. For this reason,
the piezoelectric element 70 is used in a high sound reproduction band as compared to the voice
coil 52.
[0033]
In the present embodiment, four piezoelectric elements 70 are arranged in each divided portion
14 a. Therefore, in order to correspond to the configuration of the screen speaker 10, four
piezoelectric elements 70 are disposed on the back surface 12a of the screen 12, and the input of
each piezoelectric element 70 is connected in parallel with the output of the signal amplifier 78.
In addition, one drive circuit 74 is provided for each of the divisions 14 a.
[0034]
As shown in FIG. 14, when the voice coil 52 alone is driven, the frequency characteristics of the
screen speaker system 10 have stable output sound pressure over a frequency band of 200 Hz to
10 kHz as shown in FIG. Indicates Further, when only the piezoelectric element 70 is driven,
stable output sound pressure is shown over a frequency band of 2 kHz to 15 kHz as shown in
FIG. And when it drives using these together, as shown in FIG.14 (c), the relatively stable output
sound pressure is shown over the frequency band of 200 Hz-15 kHz. Therefore, as compared
with the case where the screen 12 is driven only by the voice coil 52 in the screen speaker
system 10, the frequency characteristic in the high frequency range is obtained by driving the
screen 12 using the voice coil 52 and the piezoelectric element 70 in combination. It will be
possible to improve.
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[0035]
In the screen speaker system 10 configured as described above, by disposing the piezoelectric
element 70 on the back surface 12 a of the screen 12 and using it in combination with the voice
coil 52, the high frequency is higher than that when driven by the voice coil 52 alone. It is
possible to extend the side frequency band by nearly 40%. Therefore, stable sound pressure can
be obtained in the high tone range, and a three-dimensional, realistic sound effect can be
obtained.
[0036]
In the screen speaker system 10, the screen speaker system 10 can be driven only by the
piezoelectric element 70 without driving the voice coil 52 in the high sound range.
[0037]
Further, in the screen speaker system 10, the voice coil 52 is disposed at the center of each of
the divisions 14 a of the screen 12.
Accordingly, the voice coil 52 can be vertically oscillated with respect to the magnetic circuit 30.
Therefore, the voice coil 52 can be prevented from swinging obliquely with respect to the
magnetic circuit 30. Therefore, the size of the air gap 30d can be reduced, and the magnetic
circuit 30 can be miniaturized. Furthermore, the voice coil 52 can easily obtain a large amplitude
in the reproduction of the low tone range.
[0038]
In the screen speaker system 10, the high frequency range is reproduced by driving the
piezoelectric element 70. Further, compared to the amount of heat generated when the voice coil
52 is driven in the high sound range, the amount of heat generated when the piezoelectric
element 70 is driven in the high sound range is small. Therefore, the thermal expansion of the
screen 12 can be suppressed.
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[0039]
Further, in the screen speaker system 10, the piezoelectric element 70 is connected in parallel to
the voice coil 52, and the signal amplifiers 76 and 78 are separately provided on the input sides
of the voice coil 52 and the piezoelectric element 70, respectively. Reproduction of the sound
range is performed by driving the piezoelectric element 70. Therefore, adjustment of the sound
pressure and the frequency band of the piezoelectric element 70 can be performed
independently of the voice coil 52. Therefore, it is possible to improve the driving efficiency and
to reduce the cost.
[0040]
As mentioned above, although one embodiment of the present invention was described, the
present invention can be variously deformed besides this. Below, we will discuss that.
[0041]
In the above-described embodiment, four piezoelectric elements 70 are arranged near the four
corners of each divided portion 14a to drive the high frequency band, but the invention is not
limited thereto. For example, a circle outside the voice coil 52 is used. The piezoelectric element
70 may be disposed at another desired position, such as circumferentially disposed. Further, the
number of piezoelectric elements 70 is not limited to four, and may be five or more, or three or
less.
[0042]
Further, although the drive circuit 74 of the screen speaker system 10 is driven in the abovedescribed embodiment, the present invention is not limited to such a circuit configuration. For
example, as shown in FIG. 15, the output of signal amplifier 82 is connected to the input of voice
coil 52, the output of signal amplifier 84 is connected to capacitor 90, and the output of
capacitor 90 is connected to the input of piezoelectric element 70. A drive circuit 80 having such
a configuration may be employed. Also, when the screen 12 is driven using the drive circuit 80,
the signal amplifier 84 is provided, so that the input signal to the piezoelectric element 70 is
amplified independently of the input signal to the voice coil 52. It becomes possible. Also, low
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frequency may be removed by disposing a filter circuit 77 instead of the capacitor 90.
[0043]
For example, the output side of one signal amplifier may be branched to connect the voice coil
52 and the piezoelectric element 70 in parallel, and a circuit including a capacitor immediately
before the piezoelectric element 70 may be considered. When a high frequency current is
supplied to the element 70, the impedance of the capacitor is lowered, and an excessive current
flows to the piezoelectric element 70, which may break the piezoelectric element 70. Therefore, it
is necessary to provide a signal amplifier 78 separate from the voice coil 52 on the input side of
the piezoelectric element 70.
[0044]
Moreover, in the above-mentioned embodiment, although the piezoelectric element 70 which has
the same frequency characteristic as all is employ | adopted as four piezoelectric elements 70, it
is not restricted to this, The piezoelectric element 70 which has a different frequency
characteristic is By using together, the configuration of the drive circuit 74 may be so-called 3
WAY, 4 WAY or more.
[0045]
Moreover, in the above-mentioned embodiment, although three division parts 14a are provided
in the inside of case 14, it is good also as not only this but two or four or more.
Furthermore, it is not necessary to divide. Alternatively, a plurality of middle bars 18 may be
arranged in the lateral direction and the longitudinal direction of the side frame 17, and a portion
surrounded by only the middle bars 18 may be used as a divided portion.
[0046]
Moreover, in the above-mentioned embodiment, although the suspension function is not
provided between the screen 12 and the back plate 15, for example, a cushioning material made
of an independent foam rubber or the like between the screen 12 and the back plate 12 is used.
08-05-2019
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You may arrange it. By providing the suspension function between the screen 12 and the back
plate 15, the screen 12 can perform more stable vibration.
[0047]
In the above embodiment, the four piezoelectric elements 70 are connected in parallel to the
signal amplifier 78. However, the present invention is not limited to this. Four signal amplifiers
may be connected to correspond to the number of piezoelectric elements 70. 78 may be
provided, and the piezoelectric element 70 may be connected to each signal amplifier 78.
Further, not only the signal amplifier 78 but also the filter circuit 77 may be disposed to
correspond to the number of piezoelectric elements 70.
[0048]
The screen speaker of the present invention can be used in an acoustic conversion device such as
a speaker that emits sound from the entire surface of the screen.
[0049]
It is a perspective view showing a screen speaker concerning a 1 embodiment of the present
invention.
It is a perspective view which shows the state which removed the screen from the screen speaker
which concerns on one embodiment of this invention. It is a figure which shows the part of the
drive body vicinity used for the screen speaker which concerns on one embodiment of this
invention, (a) is sectional drawing which shows the state which decomposed | disassembled the
drive body, (b) is a drive It is sectional drawing which shows the state which assembled the body.
It is a perspective view which shows the housing | casing of the screen speaker which concerns
on one embodiment of this invention. It is a perspective view which shows the back plate which
comprises the housing | casing in FIG. It is a disassembled perspective view which shows the
state which mounts a backplate to a frame in the housing | casing of the screen speaker which
concerns on one embodiment of this invention. It is an enlarged view of the part shown by arrow
B in FIG. It is a fragmentary sectional view of the part cut by the KK line in FIG. It is a perspective
view at the time of seeing a magnetic circuit housing shown from FIG. 2 from upper direction. It
is a figure which shows the structure of a drive body, (a) is a disassembled perspective view
before assembling a drive body, (b) is a perspective view at the time of seeing from the back side
08-05-2019
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of a back plate in the state which assembled a drive body. FIG. It is sectional drawing cut |
disconnected by the NN line | wire in FIG. It is the schematic which shows the positional
relationship of the voice coil and piezoelectric element which are used in a screen speaker. It is a
figure which shows the structure of the drive circuit of a screen speaker system shown in FIG. It
is a figure which shows the frequency characteristic of a screen speaker system shown in FIG. 1,
(a) is a figure which shows the case where a screen speaker system is driven only by a voice coil,
(b) shows a screen speaker system. It is a figure which shows the case where it drives by only a
piezoelectric element, and (c) is a figure which shows the case where a screen speaker system is
driven by the drive circuit shown in FIG. It is a figure which shows the modification of the drive
circuit of the screen speaker system of this invention.
Explanation of sign
[0050]
DESCRIPTION OF SYMBOLS 10 ... Screen speaker system 12 ... Screen 30 ... Magnetic circuit 50 ...
Driver 52 ... Voice coil 70 ... Piezoelectric element 76, 82 ... Signal amplifier (1st amplifier) 77 ...
Filter circuit 78, 84 ... Signal amplifier (2nd amplifier)
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